recovery of gold from ores with chlorine in 1898

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recovery of gold from ores with chlorine in 1898

Postby Traveller11 » November 25th, 2012, 7:37 pm

From "Getting Gold: A practical treatise for prospectors, miners and students" Written by J.C.F. Johnson, F.G.S. (1898)


The most scientific and perfect mode of gold extraction (when the conditions are favourable) is lixiviation by means of chlorine, potassium cyanide, or other aurous solvent, for by this means as much as 98 per cent of the gold contained in suitable ores can be converted into its mineral salt, and being dissolved in water, re-deposited in metallic form for smelting; but lode stuff containing much lime would not be suitable for chlorination, or the presence of a considerable proportion of such a metal as copper, particularly in metallic form, would be fatal to success, while cyanide of potassium will also attack metals other than gold, and hence discount the effect of this solvent.

The earlier practical applications of chlorine to gold extraction were known as Mears' and Plattner's processes, and consisted in placing the material to be operated on in vats with water, and introducing chlorine gas at the bottom, the mixture being allowed to stand for a number of hours, the minimum about twelve, the maximum forty-eight. The chlorinated water was then drawn off containing the gold in solution which was deposited as a brown powder by the addition of sulphate of iron.

Great improvements on this slow and imperfect method have been made of late years, among the earlier of which was that of Messrs. Newbery and Vautin. They placed the pulp with water in a gaslight revolving cylinder, into which the chlorine was introduced, and atmospheric air to a pressure of 60 lb. to the square inch was pumped in. The cylinder with its contents was revolved for two hours, then the charge was withdrawn and drained nearly dry by suction, the resultant liquid being slowly filtered through broken charcoal on which the chloride crystals were deposited, in appearance much like the bromo-chlorides of silver ore seen on some of the black manganic oxides of the Barrier silver mines. The charcoal, with its adhering chlorides, was conveyed to the smelting-house and the gold smelted into bars of extremely pure metal. Messrs. Newbery and Vautin claimed for their process decreased time for the operation with increased efficiency.

At Mount Morgan, when I visited that celebrated mine, they were using what might be termed a composite adaptation process. Their chlorination works, the largest in the world, were putting through 1500 tons per week. The ore as it came from the mine was fed automatically into Krom roller mills, and after being crushed and sifted to regulation gauge was delivered into trucks and conveyed to the roasting furnaces, and thence to cooling floors, from which it was conveyed to the chlorinating shed. Here were long rows of revolving barrels, on the Newbery-Vautin principle, but with this marked difference, that the pressure in the barrel was obtained from an excess of the gas itself, generated from a charge of chloride of lime and sulphuric acid. On leaving the barrels the pulp ran into settling vats, somewhat on the Plattner plan, and the clear liquid having been drained off was passed through a charcoal filter, as adopted by Newbery and Vautin. The manager, Mr. Wesley Hall, stated that he estimated cost per ton was not more than 30s., and he expected shortly to reduce that when he began making his own sulphuric acid. As he was obtaining over 4 oz. to the ton the process was paying very well, but it will be seen that the price would be prohibitive for poor ores unless they could be concentrated before calcination.

The Pollok process is a newer, and stated to be a cheaper mode of lixiviation by chlorine. It is the invention of Mr. J. H. Pollok, of Glasgow University, and a strong Company was formed to work it. With him the gas is produced by the admixture of bisulphate of sodium (instead of sulphuric acid, which is a very costly chemical to transport) and chloride of lime. Water is then pumped into a strong receptacle containing the material for treatment and powerful hydraulic pressure is applied. The effect is stated to be the rapid change of the metal into its salt, which is dissolved in the water and afterwards treated with sulphate of iron, and so made to resume its metallic form.

It appears, however, to me that there is no essential difference in the pressure brought to bear for the quickening of the process. In each case it is an air cushion, induced in the one process by the pumping in of air to a cylinder partly filled with water, and in the other by pumping in water to a cylinder partly filled with air.
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I'm a bit short of time right now but tomorrow or the next day I would like to explore how the HCl/Clorox process evolved from this method. I also believe that a very basic mistake was made and that the HCl/Clorox method has far more potential for dealing with black sand concentrates than has been believed up to this point. Read this article very carefully and check back in a couple of days. There are several very important clues in this article.
"He was always cold, but the land of gold seemed to hold him like a spell....Though he'd often say, in his homely way, that he'd "sooner live in Hell"....." ~~Robert W. Service~~

"When you live beside the graveyard, you can't cry for every funeral." - Russian Proverb

"Good judgement comes from experience, and a lot of that comes from bad judgement." ~~Will Rogers~~


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Re: recovery of gold from ores with chlorine in 1898

Postby Traveller11 » December 8th, 2012, 10:37 pm

I would like to begin a discussion of the various ways of leaching gold with chlorine and the similarities between them. I would first like to re-post the post that first started me wondering about the possibility of using a chlorine leach with an iron rich ore. Here, once again, from james122964, and hats off to this rebel and independent thinker:

From james122964:

I would try the HCL/chlorox leach first, but use a sealed container, cut way down on the HCL, and use enough chlorox to convert nearly all of the HCL to chorine gas.
DO not use a glass container, use a 5gl bucket with lid.

I use this for IC chips. I put the ground chips in to about 1/3 of the bucket deep, then I use HCL which the amount depends on the expected metal content, to much does not hurt but is wastefull, I put this in a plastic drink cup (disposable) and force it down into the ground material (so it does not spill) I then add the chlorox which is also in a plastic cup and force down so it will not spill.

I drill a 1/2 inch hole in the lid (relief valve, kinda thing) that I have a rubber stopper to fit. snap the lid on tight. Now here is the tricky part, tip the bucket so the HCL and chlorox mix, then set the bucket back level and test for chlorine gas coming out of the hole with a q-tip that has been dipped in ammonia, white fumes will tell that the bucket is full of chlorine, once this happens cork the hole and roll the bucket around to mix the chlorine gas with the "ore" leave this set for at least 24 hours, rolling again to mix about every six hours or so.

When this is done you can extract the gold by rinsing with water and draining, I reuse the water several times to get a high enough concentration to drop the gold from.
You can then extract your silver chloride with the thiosulfate, I do not bother because of the low value of silver and low content in my IC powder. If your ore has higher then it may be worth it.

The HCL is what reacts with the iron oxides, by eliminating the excess HCL and using chlorine gas, hardly any of the iron compounds are reacted with.

I think if you get the process above down, then you will not really want to use the thio, as you skip many steps involved in the thio process.

This is my adaptation of the Plattners Process that has been used for 100 or so years.

Jim
~~end quote~~

What surprised me the most is that when james posted this, it was completely ignored (except for myself). And yet, if his reports are accurate, he seems to have solved the age old problem of separating ultra fine gold from ores rich in iron oxides, using nothing but solutions available at any hardware store.

The gist of what james is saying seems to boil down to using way less HCl than usual in the HCl/NaOCl process, ultimately leading to a leach with a much higher, though still acidic, ph. I have read many times on this forum that it requires a very low ph to put iron oxides into solution. I wonder if this is what prompted james to try using less HCl in his process?

Let's take a look at what actually happens when HCl is added to NaOCl bleach.

NaOCl bleach (6%) is a mixture of 94% water and 6% NaOCl. It is often produced by the electrolysis of NaCl and water but it can also be produced by mixing hypochlorous acid (HOCl) and sodium hydroxide (NaOH). HOCl + NaOH = NaOCl + H2O. When NaOCl is produced by the electrolysis method, NaOH is added to it until the ph of the NaOCl bleach is raised over 12. This stops NaOCl from becoming HOCl.

So, what happens in the HCl/NaOCl leach when HCl is added to NaOCl? First, the ph drops below the critical 11.86 point and hypochlorous acid (HOCl) and sodium hydroxide (NaOH) are formed. NaOH and HCl react to form NaCl + H2O, neutralizing each other. More HCl is added, negating more NaOH until an acidic solution of HOCl and H2O is achieved. The question is, just how low does the ph have to go to put gold into solution? And an even better question is, do we have to keep lowering the ph until Cl2 gas is formed or can we use the acidic solution of HOCl and H2O at a higher ph, to dissolve gold, without making Cl2 gas?

This is what makes james' process of using so much less HCl so interesting. By doing so, he obviously does not achieve a ph of 1 or 2 but is likely more in the range of 5-6. Looking at the Plattner's Process in my first post, I believe these fellows in 1898 were achieving exactly the same objective, just starting out with different compounds. By introducing Cl2 gas, under pressure, to a mixture of water and ore, they caused the Cl2 to be dissolved in water that began with a neutral ph of 7. Once dissolved, Cl2 combines with water to make HOCl and HCl. As the water was ph 7 to begin with, and a limited amount of these two acids would be formed by adding Cl2 to water, would the final ph of the leach solution not be identical to the james122964 variation of the HCl/NaOCl leach solution, likely in the range of 5-6? Have they not made exactly the same thing at almost the same ph?

I know this post is getting a bit long but, carefully read this material below from the 1890's and tell me if the sodium hypochlorite solution (ultimately becoming hypochlorous acid) produced by this electrolytic method does not ultimately become the same solution as james122964's variation of HCl/NaOCl or the original Plattner's Process in my first post. Remember, NaOCl produced electrolytically does not have the 12+ ph of NaOCl sold as bleach (no NaOH added to it) and does not require copious amounts of HCl to bring its ph under 7.

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Electrolytic Precipitation of Gold








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In order to perform the electrolytic precipitation of gold, from the filtration vessel the gold chloride solution was conducted into the outer or battery jar of an electrolytic cell. The electrode of the outer cell was connected with the negative pole of a dynamo and the electrode on the inner cell was connected with positive pole or terminal of the dynamo. The gold solution was sent into the jar near the bottom and slowly circulated upwards, and at the same time a current of electricity was passes through the cell. When the reaction was produced, the gold chloride was decomposed and felt like a shower of fine spangles to the bottom, while the liberated chlorine passed into the inner cell where it was absorbed by the water circulating and formed a chlorine solution.

The receiver was charged with chlorine solution generated by the electrolysis of salt. The unit comprised a battery, a conductor from the electrode in the large battery jar to the negative pole of the electrical generator, the conductor from the electrode in the porous cell to the positive pole of the generator, a reservoir containing a saturated solution of sodium chloride, which passed to the battery through a pipe and a reservoir containing water connected by a pipe with a porous cell.

In order to treat the ore more effectually with the chlorine solution it was advantageous to expel the air from the chlorinator. For this purpose the chlorinator was provided with a valve, so that the air contained in the chlorinator passed out as the chlorine solution passed in. the valve was closed immediately the air was expelled. The chlorinator after disconnected was slowly revolved by means of a pulley and strap from an engine, or in other suitable way until the gold was dissolved as a gold chloride. The time required for treatment in the chlorinator varied from one to two hours according to the characteristics of the gold ore treated. The ore and solution were discharged into a suitable filtration vessel placed beneath the chlorinator. The vessel was a shallow vat constructed of oak or other material, the lower part was made cone-shaped and of the same capacity of the chlorinator.

The vat was closed by a cover bolted down. In the center of the cover there was hopper-shaped inlet for receiving the ore and solution from the chlorinator. A perforated diaphragm covered with asbestos cloth, over which was advantageously placed a layer of other suitable filtration media such as ground asbestos, which was fixed from one to two inches below the top of the vat. The gold chloride was washed out of the ore by a stream of water from a tank. The water entered the vat through a pipe at the lowest part and percolated upwards through the ore until the gold content in the solution was extremely low. It was important to take samples of the solution to determine the presence of gold. A sliding door in the bottom of the vat was opened and the residue from the ore as discharged by means of a large outlet opened into a truck placed underneath.

The gold chloride and water descended through a pipe into a receiver and was conducted from the receiver into the outer or battery jar of the electrolytic cell. The gold solution flowed into and entered the jar at the bottom and slowly circulated upwards and at the same time a current of electricity was passé through the cell to reduce and precipitate gold from the solution into a perfectly pure state, upon the bottom of the jar, from where it was removed. The chlorine was liberated at the same time at the electrode in the inner or porous cell and in contact with the water circulating and formed a chlorine solution, which was sent to receiver vessel.
"He was always cold, but the land of gold seemed to hold him like a spell....Though he'd often say, in his homely way, that he'd "sooner live in Hell"....." ~~Robert W. Service~~

"When you live beside the graveyard, you can't cry for every funeral." - Russian Proverb

"Good judgement comes from experience, and a lot of that comes from bad judgement." ~~Will Rogers~~

butcher
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Re: recovery of gold from ores with chlorine in 1898

Postby butcher » December 9th, 2012, 2:09 pm

Roasting the ore would be a very important step, no only to drive off sulfates but also to help form acid resistant iron hydroxide, to help keep from leaching iron as much as possible in the acidic leach (as you described in your other post).

Hypochlorite is basic (with NaOH keeping the chlorine in the water) to generate chlorine gas we need to make it acidic (if electrolysis is not involved), if electrolysis is involved we can generate chlorine by splitting a chloride salt, the sodium Na+ to the cathode, the chlorite CLO- to the anode to generate chlorine, water in the solution will also split to hydrogen H+ and hydroxides OH- hydrogen gas would gas off of cathode.

In electrolysis salts of chlorides the anode can form chlorine, the cathode can form hydroxides (one reason for the split cell salt bridge, or asbestos sheet membrane separating these two compartments of the cell to assist to keep these from mixing back together) to keep the negative hydroxides from moving to the anode and also to help to keep a rich sodium chloride solution around the anode to generate chlorine gas from.

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Re: recovery of gold from ores with chlorine in 1898

Postby Traveller11 » December 9th, 2012, 3:30 pm

butcher wrote:Roasting the ore would be a very important step, no only to drive off sulfates but also to help form acid resistant iron hydroxide, to help keep from leaching iron as much as possible in the acidic leach (as you described in your other post).

Hypochlorite is basic (with NaOH keeping the chlorine in the water) to generate chlorine gas we need to make it acidic (if electrolysis is not involved), if electrolysis is involved we can generate chlorine by splitting a chloride salt, the sodium Na+ to the cathode, the chlorite CLO- to the anode to generate chlorine, water in the solution will also split to hydrogen H+ and hydroxides OH- hydrogen gas would gas off of cathode.

In electrolysis salts of chlorides the anode can form chlorine, the cathode can form hydroxides (one reason for the split cell salt bridge, or asbestos sheet membrane separating these two compartments of the cell to assist to keep these from mixing back together) to keep the negative hydroxides from moving to the anode and also to help to keep a rich sodium chloride solution around the anode to generate chlorine gas from.


I fail to understand why you are so stuck on the idea of making chlorine gas.
"He was always cold, but the land of gold seemed to hold him like a spell....Though he'd often say, in his homely way, that he'd "sooner live in Hell"....." ~~Robert W. Service~~

"When you live beside the graveyard, you can't cry for every funeral." - Russian Proverb

"Good judgement comes from experience, and a lot of that comes from bad judgement." ~~Will Rogers~~

butcher
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Re: recovery of gold from ores with chlorine in 1898

Postby butcher » December 9th, 2012, 5:07 pm

I do not know I guess to get the gold to form a gold chloride.

I was under the assumption that was the purpose to get the gold in an state of oxidation through electrolysis (or with chlorine in the case of HCl/NaCLO with chlorine dissolved in solution) and then get the gold to form a gold chloride from the attaching the ion to the free chloride ions in solution.

Without oxidizing the gold how would you get the gold to form chlorides, chlorides alone will not oxidize elemental gold, the chloride have all of their electrons and will not take an electron from the gold atom, unless we can remove an atom from the gold first it will not form gold chloride (this is why gold will not dissolve in HCl alone, the acid is not a strong enough oxidizer, but when we add chlorine gas dissolved in solution the chlorine in its elemental form is missing electrons, it will easily take an electron form the gold, the chlorine now with a full shell of electrons now forms a salt of chloride ion, this gold ion with the missing electron can now be joined to three chloride ions to form a solution of gold chloride.

You will need to oxidize the gold before it can join with chloride ions, how would you oxidize the gold without an oxidizer like chlorine or nitric acid?
In a salt cell we generate chlorine at the anode when we split the salt, and the salt also supply's a ready supply of chloride ions for the gold to attach to.

I guess I am missing something here with where you are going with this idea, but at this point I do not understand what it is.

Maybe I am just missing the point completely?


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Re: recovery of gold from ores with chlorine in 1898

Postby Traveller11 » December 9th, 2012, 5:34 pm

butcher wrote:I do not know I guess to get the gold to form a gold chloride.
I was under the assumption that was the purpose to get the gold in an state of oxidation through electrolysis (or chlorine in the case of HCl/NaCLO with chlorine in solution) and then get the gold to form a gold chloride from the attaching chloride ions in solution.

Maybe I am missing the point?


I believe the words "chlorine in solution" pretty much sum up what I am trying to say. In the thread "Salt Water Electrolytic Cell", I quoted a description, from the 1890's, of an electrolytic cell that created, from salt water, a chlorine solution that would, in a separate chlorinator, put gold into solution as a chloride. The same cell would also dissociate this gold chloride into gold and chlorine gas. BUT, the recycled chlorine gas existed only briefly at the anode before it became a chlorine solution and was returned to the chlorinator to dissolve more gold.

The electrolytic cell described in the article can only be one thing; a sodium hypochlorite generator. It may also have produced sodium chlorate in solution, depending on the temperature the cell ran at, but I believe the main product was sodium hypochlorite. We know it was not making chlorine gas because nowhere in the article does it mention a membrane separating the anode and the cathode. Also, from the cell, it says a chlorine solution, and not chlorine gas, is sent to the chlorinator to dissolve gold. There is also no mention of HCl being added to the NaOCl to allow the release of Cl2 gas. We can only assume this solution had a ph of 5-6, created when sodium hypochlorite in water at a ph of less than 11.86 becomes hypochlorous acid.

In other words, the chlorine solution from this cell was able to put gold into solution without making one wisp of Cl2 gas.
"He was always cold, but the land of gold seemed to hold him like a spell....Though he'd often say, in his homely way, that he'd "sooner live in Hell"....." ~~Robert W. Service~~

"When you live beside the graveyard, you can't cry for every funeral." - Russian Proverb

"Good judgement comes from experience, and a lot of that comes from bad judgement." ~~Will Rogers~~

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Re: recovery of gold from ores with chlorine in 1898

Postby butcher » December 9th, 2012, 8:42 pm

OK from the sounds of it, we can still be talking the same language,

I did not necessarily mean the chlorine had to leave solution as a gas,
But the chlorine will still be generated at the anode from the solution, the chloride is reduced at the anode to chlorine, Gas whether it leaves as gas or reacts with gold or other salts acids or bases in solution and stays in solution as another form, the electrical current is taking electrons from the chloride to make elemental chlorine at the anode. the chlorine can now take electrons from the gold so the gold can be bound to three free chlorides in solution. or the chlorine could mix with water in a basic solution and make chlorides or chlorates, or if solution was acidic leave as a gas, Much of whether the chlorine generated at the anode will leave the cell as gas or stay in the cell to react, can be several factors, temperature, pH, dilution, reaction with other metals (acids or hydroxides or other salts in the cell), current and voltage and so on.

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Re: recovery of gold from ores with chlorine in 1898

Postby Traveller11 » December 9th, 2012, 9:26 pm

butcher wrote:OK from the sounds of it, we can still be talking the same language,

I did not necessarily mean the chlorine had to leave solution as a gas,
But the chlorine will still be generated at the anode from the solution, the chloride is reduced at the anode to chlorine, Gas whether it leaves as gas or reacts with gold or other salts acids or bases in solution and stays in solution as another form, the electrical current is taking electrons from the chloride to make elemental chlorine at the anode. the chlorine can now take electrons from the gold so the gold can be bound to three free chlorides in solution. or the chlorine could mix with water in a basic solution and make chlorides or chlorates, or if solution was acidic leave as a gas, Much of whether the chlorine generated at the anode will leave the cell as gas or stay in the cell to react, can be several factors, temperature, pH, dilution, reaction with other metals (acids or hydroxides or other salts in the cell), current and voltage and so on.


Precisely. But, if the ph of the water is close to 7 before the NaCl is added to it, electrolyzing the brine should give you a mildly acidic solution of water and hypochlorous acid. Adding a limited amount of HCl to a basic solution of NaOCl in water should give us the same thing. I believe this is what james122964 tumbled to about the HCl/Clorox method; the fact that far too much HCl was being added, reducing the ph to 1-2, and iron and its oxides were being dissolved along with the gold (as well as copious amounts of CL2 gas being given off).

I'm waiting for a ph meter to arrive from an Ebay site I ordered it from. I have a great deal of black sand gathered from a place assayed many times over and found to have goodly amounts of microscopic gold. I plan to prepare a leach solution from Clorox by slowly adding minute amounts of HCl to it until the ph is just below 7. I will prepare similar solutions at 6.5, 6, 5.5, 5 and 4.5. Each will be applied to an equal amount of black sand concentrate, filtered and the resulting solution tested with SnCl.
"He was always cold, but the land of gold seemed to hold him like a spell....Though he'd often say, in his homely way, that he'd "sooner live in Hell"....." ~~Robert W. Service~~

"When you live beside the graveyard, you can't cry for every funeral." - Russian Proverb

"Good judgement comes from experience, and a lot of that comes from bad judgement." ~~Will Rogers~~

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Re: recovery of gold from ores with chlorine in 1898

Postby butcher » December 9th, 2012, 10:04 pm

we could start an electrolytic with neutral pH salt, but as we ran the cell the pH could change drastically during operation.

H+ + OH- --> H2O water is neutral pH at the cathode in the electrolytic cell the H+ will move to the cathode, The OH- will move to the anode, the H+ is reduced at the cathode as hydrogen gas leaving the cell as H2 gas, now the pH of the cell becomes basic.

I Know now I am so stuck on hydrogen gas :lol:

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Re: recovery of gold from ores with chlorine in 1898

Postby Traveller11 » December 10th, 2012, 2:12 am

butcher wrote:we could start an electrolytic with neutral pH salt, but as we ran the cell the pH could change drastically during operation.

H+ + OH- --> H2O water is neutral pH at the cathode in the electrolytic cell the H+ will move to the cathode, The OH- will move to the anode, the H+ is reduced at the cathode as hydrogen gas leaving the cell as H2 gas, now the pH of the cell becomes basic.

I Know now I am so stuck on hydrogen gas :lol:



LOL :lol: Well, you do bring up a good point. Not one of these 100+ year old articles I've been reading ever once state, "...and when the chlorine solution came out of the electrolytic cell, on its way to the chlorinator, it had a ph of (__) ..." or "......and when the chlorine gas was forced into the chlorinator at 60 psi and dissolved in the water contained there, the resulting ph of the chlorine solution was (__)...". Even james122964, with his variation of the HCl/Clorox process that used a greatly reduced volume of HCl, does not tell us what the resulting ph of his solution is.

This leads me to ask, does a chlorine leach actually have to be acidic to be able to put gold into solution as auric chloride? Any idea what the best ph would be to dissolve gold and avoid dissolving iron oxides?
"He was always cold, but the land of gold seemed to hold him like a spell....Though he'd often say, in his homely way, that he'd "sooner live in Hell"....." ~~Robert W. Service~~

"When you live beside the graveyard, you can't cry for every funeral." - Russian Proverb

"Good judgement comes from experience, and a lot of that comes from bad judgement." ~~Will Rogers~~

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Re: recovery of gold from ores with chlorine in 1898

Postby Platdigger » December 10th, 2012, 2:39 am

No, I have heard of it being done on the alkaline side (with chlorine) as well.

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Re: recovery of gold from ores with chlorine in 1898

Postby Traveller11 » December 10th, 2012, 2:53 am

Platdigger wrote:No, I have heard of it being done on the alkaline side (with chlorine) as well.


Thanks for that, Platdigger. I guess this means I'll have to expand my experiment to include basic solutions of chlorine, as well.
"He was always cold, but the land of gold seemed to hold him like a spell....Though he'd often say, in his homely way, that he'd "sooner live in Hell"....." ~~Robert W. Service~~

"When you live beside the graveyard, you can't cry for every funeral." - Russian Proverb

"Good judgement comes from experience, and a lot of that comes from bad judgement." ~~Will Rogers~~

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Re: recovery of gold from ores with chlorine in 1898

Postby Gratilla » December 10th, 2012, 6:35 am

james122964, I believe, is the same James that has been sharing his chlorine method for some years over on MicronGold Yahoo Group. Also, Art, the late founder of the group, did quite a bit of work on a salt cell some years ago. A search of the message and file archives should turn up some interesting hits.

BTW, has anyone considered corresponding directly with the SALTEM patent holders? As a semi-govt org committed to stamping out artisinal mercury use, I doubt they would be secretive about their system. I would be interested in details of any up-and-running systems. If they require parties nearby artisinal mercury users in order to correspond, I'll volunteer (in return for an email address) - lots of kampung Hg users in these parts.

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Re: recovery of gold from ores with chlorine in 1898

Postby Traveller11 » December 10th, 2012, 11:01 am

Gratilla wrote:james122964, I believe, is the same James that has been sharing his chlorine method for some years over on MicronGold Yahoo Group. Also, Art, the late founder of the group, did quite a bit of work on a salt cell some years ago. A search of the message and file archives should turn up some interesting hits.

BTW, has anyone considered corresponding directly with the SALTEM patent holders? As a semi-govt org committed to stamping out artisinal mercury use, I doubt they would be secretive about their system. I would be interested in details of any up-and-running systems. If they require parties nearby artisinal mercury users in order to correspond, I'll volunteer (in return for an email address) - lots of kampung Hg users in these parts.


I have made an effort to contact people within SALTEM to find out more information about this process. It does not seem to be something that is being actively pursued by them at this time. No one there is able to provide me with anything more than the sketchiest details.

All things considered, the SALTEM electrolytic process is so simple, I think the easiest thing to do is just go out and build a cell. It seems graphite or titanium electrodes would be most suitable.

I just wish it had been stated whether the cell was making sodium hypochlorite or sodium chlorate. The same cell can make either compound, depending on the current applied and the resulting cell temperature. Below, 50° C., sodium hypochlorite is produced. Between 50-70° C., sodium chlorate is produced. I was a bit concerned that, once sodium chlorate (NaClO-3) was made, that the cell could then go on to make sodium perchlorate (NaClO-4, and ultimately perchloric acid - a very dangerous substance to have around) but I found, through further study, that making perchlorate in a cell is a fairly complicated thing to do and not something that would happen by accident.
"He was always cold, but the land of gold seemed to hold him like a spell....Though he'd often say, in his homely way, that he'd "sooner live in Hell"....." ~~Robert W. Service~~

"When you live beside the graveyard, you can't cry for every funeral." - Russian Proverb

"Good judgement comes from experience, and a lot of that comes from bad judgement." ~~Will Rogers~~

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Re: recovery of gold from ores with chlorine in 1898

Postby NoIdea » December 11th, 2012, 12:18 am

Anyone see this, might point to something a little different, too many assumptions though for my liking. 8

http://labmem.unsl.edu.ar/Publicados/Ojeda_09.pdf

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Re: recovery of gold from ores with chlorine in 1898

Postby Traveller11 » December 31st, 2012, 11:35 pm

Platdigger wrote:No, I have heard of it being done on the alkaline side (with chlorine) as well.


Here is confirmation of what you have heard. I found this on the Prospector's Paradise. Unfortunately, the guy who wrote it passed away a while ago. I would have loved to discuss this with him.

"Remember chlorine is very slow. You will have to maintain this system for several hours to a day or more.

Like all of the halides, if you allow the solution to go acid, the chlorine will rapidly boil off and if you are close by will be extremely uncomfortable. Bromine and iodine are not so bad. They are not nearly so volatile and will give you a little more time to rectify the situation by addition of a little lye water.

If you are extracting with halides, in particular, chlorine where you have no visual reference as to what is happening, you should have some hydrochloric (muriatic) or sulfuric acid at hand. If your reaction should start to slow down and you are sure you have an excess of halide in solution you might have to add a little acid in order to liberate the halide from it’s salt form in order to keep sufficient free halide to ensure a good extraction. If you can keep the pH at say 8.5 you will be about right.

If chlorine production should get out of hand, you probably should have some solution of sodium thiosulfate on hand. It can be bought from any chemical supply. This is the stuff that tropical fish freaks use to treat tap water to destroy chlorine. You will need much more than they use however. This is a good way to neutralize any solution you wish to dump. Your neighbors will probably appreciate your thoughtfulness."
"He was always cold, but the land of gold seemed to hold him like a spell....Though he'd often say, in his homely way, that he'd "sooner live in Hell"....." ~~Robert W. Service~~

"When you live beside the graveyard, you can't cry for every funeral." - Russian Proverb

"Good judgement comes from experience, and a lot of that comes from bad judgement." ~~Will Rogers~~

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Re: recovery of gold from ores with chlorine in 1898

Postby Barren Realms 007 » January 1st, 2013, 9:53 am

Would the use of slow dissolving chlorine tablets keep a supply of chlorine in the solution and just keep a check on the PH?
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Re: recovery of gold from ores with chlorine in 1898

Postby Traveller11 » January 1st, 2013, 12:38 pm

Barren Realms 007 wrote:Would the use of slow dissolving chlorine tablets keep a supply of chlorine in the solution and just keep a check on the PH?


The idea never occurred to me but, thinking it over, it might be an incredibly effective way of mimicking the original Pattner's & Mears' Process in which chlorine gas was bubbled up through a mixture of ground ore and water and, once enough Cl2 was in solution, the vessel was turned for several hours to leach the gold out of the ore. They found, of course, that the Cl2 gas went into solution quicker if the vessel was pressurized with air to 60 psi. The Cl2 put into solution combined with the water to make hydrochloric and hypochlorous acid (HCl + HOCl).

I've never encountered slow dissolving chlorine tablets before. Do you know the chemical compound for them? Do they release Cl2 gas or Cl2 in solution? I'm wondering if they are not calcium hypochlorite (Ca(ClO)2) tablets for making swimming pool chlorine. I think calcium hypochlorite would be more effective than using sodium hypochlorite (NaClO) bleach because you can make a stronger solution than what is available as bleach in the store. Also, as I mentioned earlier, because it has sodium hydroxide (NaOH) added as a preservative, household bleach has a ph of over 12 and requires the addition of an acid to bring it down to a lower ph.

Let me know what you find out about these tablets. I'm still waiting for my ph meter to show up so I can begin experimenting with NaClO and HCl.

*NOTE*

Additional research has proven me wrong about calcium hypochlorite making a solution near neutral in ph. In truth, a 1% solution of calcium hypochlorite in water has a ph of up to 10.8. It makes sense; if the solution was at a ph of 7, it would be hypochlorous acid instead of calcium hypochlorite.
Last edited by Traveller11 on January 3rd, 2013, 3:10 am, edited 1 time in total.
"He was always cold, but the land of gold seemed to hold him like a spell....Though he'd often say, in his homely way, that he'd "sooner live in Hell"....." ~~Robert W. Service~~

"When you live beside the graveyard, you can't cry for every funeral." - Russian Proverb

"Good judgement comes from experience, and a lot of that comes from bad judgement." ~~Will Rogers~~

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Re: recovery of gold from ores with chlorine in 1898

Postby Barren Realms 007 » January 1st, 2013, 4:50 pm

For the small pool tablets they are 99% Trichlor-S-Triazinetrine.

http://www.intheswim.com/Pool-Chemicals ... e-Tablets/

Or you can go with the large ones that are 79%.

http://www.intheswim.com/Pool-Chemicals ... mmer-Tabs/

Graular chlorine Contains premium-quality 56% available stabilized chlorine. 99% Sodium Dichloro-S-Triazinetrione Dihydrate.

http://www.intheswim.com/Pool-Chemicals ... -Chlorine/

But don't mix the granular and the tablets together in an inclosed container.

I have used the granular chlorine in some applications but have not used the tablets.

They are desighned the dissolve in the water and mix the chlorine with the water.
Give a man a fish and you feed him for a day, teach a man to fish and you feed him for life.
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Re: recovery of gold from ores with chlorine in 1898

Postby Traveller11 » January 1st, 2013, 6:10 pm

Barren Realms 007 wrote:For the small pool tablets they are 99% Trichlor-S-Triazinetrine.

http://www.intheswim.com/Pool-Chemicals ... e-Tablets/

Or you can go with the large ones that are 79%.

http://www.intheswim.com/Pool-Chemicals ... mmer-Tabs/

Graular chlorine Contains premium-quality 56% available stabilized chlorine. 99% Sodium Dichloro-S-Triazinetrione Dihydrate.

http://www.intheswim.com/Pool-Chemicals ... -Chlorine/

But don't mix the granular and the tablets together in an inclosed container.

I have used the granular chlorine in some applications but have not used the tablets.

They are desighned the dissolve in the water and mix the chlorine with the water.


Interesting. I wonder if they end up producing hypochlorous acid once dissolved.

Once I get my ph meter and get the experiment up and running, I'll purchase some of these tablets and see if they are reactive with gold.

Happy New Year!
"He was always cold, but the land of gold seemed to hold him like a spell....Though he'd often say, in his homely way, that he'd "sooner live in Hell"....." ~~Robert W. Service~~

"When you live beside the graveyard, you can't cry for every funeral." - Russian Proverb

"Good judgement comes from experience, and a lot of that comes from bad judgement." ~~Will Rogers~~

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Re: recovery of gold from ores with chlorine in 1898

Postby Traveller11 » January 1st, 2013, 6:39 pm

Hi Realms

I did a little searching and found this site:

http://www.stabilised-chlorine-tablet.co.uk/

The formula for this compound, trichloro-s-triazinetrione (trichloroisocyanuric acid), is C3Cl3N3O3 and this article states that, when mixed with water, the chlorine becomes hypochlorous acid. It does have a tendency to lower ph as it also produces isocyanuric acid, which may or may not be a good thing, depending on what my experiments turn up.

The only disadvantage I can see is the slow release thing. It might be just as easy to buy dry calcium hypochlorite and mix it with water, again giving us the hypochlorous acid.
"He was always cold, but the land of gold seemed to hold him like a spell....Though he'd often say, in his homely way, that he'd "sooner live in Hell"....." ~~Robert W. Service~~

"When you live beside the graveyard, you can't cry for every funeral." - Russian Proverb

"Good judgement comes from experience, and a lot of that comes from bad judgement." ~~Will Rogers~~

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Re: recovery of gold from ores with chlorine in 1898

Postby Traveller11 » January 5th, 2013, 11:25 pm

Interesting article about the hypochorous acid <--> hypochlorite shift (HOCl <--> OCl) that is mandated by the ph of the chlorine solution.

http://www.poolhelp.com/HOCI_OCI.aspx

As HOCl is the most active oxidiser of the two (80-120 x more so than OCl) it is desirable to maximise the HOCL, which happens at a ph of 5 (see chart on link). However, as ph 5 is acidic, it may be necessary to compromise for a lower percentage of HOCl, by raising the ph closer to 7, to avoid the release of chlorine gas and the dissolving of iron and its oxides at the lower ph's.
"He was always cold, but the land of gold seemed to hold him like a spell....Though he'd often say, in his homely way, that he'd "sooner live in Hell"....." ~~Robert W. Service~~

"When you live beside the graveyard, you can't cry for every funeral." - Russian Proverb

"Good judgement comes from experience, and a lot of that comes from bad judgement." ~~Will Rogers~~

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Re: recovery of gold from ores with chlorine in 1898

Postby Traveller11 » January 7th, 2013, 2:43 pm

Chlorination. I - from the "Australian Town and Country Journal (NSW)" January 31, 1891

The chlorination process of extracting gold From its matrix, and from from concentrates, is freely alluded to in newspapers and amongst miners; and yet, as a rule, the principle is but vaguely understood, even by men who make mining their business. Our explanation will be principally for persons who understand but little, if anything, of chemistry. To the scientific man, the great affinity of chlorine for the precious metals has been known almost ever since the distinguished German chemist, Schule, first discovered chlorine, about the year 1774. Chlorine, then, is an element, that is a simple substance, out of which nothing can be produced but itself. It is a gas, and has many remarkable properties- bleaching almost all colored substances, and being very heavy as compared with common air, and being also very deleterious to breathe. It is largely consumed by man and the lower animals in food as common salt, which contains a little more than half of pure chlorine. It conies into uso in mining in consequence chiefly of its great affinity or liking for gold and silver. If it can get sufficiently near it will seize hold of them, appropriating a certain portion to itself, making what is called chloride of gold ot silver. It being so abundant in nature, salt being so common, it is made cheaply-a little dilute sulphuric acid put on salt liberates chlorine gas, and its attraction for silver can be witnessed by the curious any day in the Sydney Mint by watching the chlorine gas being put into the bottom of the molten gold in the pot, and as it bubbles up to top seeing it seize hold of the silver, carrying it to the top of the gold as a chloride of silver. In using chlorine to extract gold you simply crush the stone or matrix so fine that it can get at the gold and take hold of it as a chloride. The easiest way to do this is to'put the chlorine in a solution in water, and so powerful is its action on gold that it dissolves that metal, holding it in
solution as water holds sugar. There is no difficulty in making a solution of chlorine, as at ordinary temperatures water dissolves about twice its volume of chlorine. Thus then having liberated the gold from the stone by crushing, and having made chlorine gas, as can be done cheaply, say from common salt, and having passed the chlorine so made through water, and thus made a solution of chlorine, and bringing it and the crushed stone together, in a short time you have your chlorine solution, containing all the gold in solution that was in the crushed stone. Having then the auriferous chlorine solution decanted or run off from the sludge or crushed stone or pyrites, you put some thing into it which will deposit or throw down the gold. Either one of two things, both of them very cheap and easily obtained, will do this effectuality, viz., a solution of sulphate of iron, common green vitrol, or pieces of common wood charcoal. The first will throw all the gold down as a powder ; the other, wood charcoal, will take to itself the gold out of the solution as a brown film, and upon the charcoal being burned away the pure gold remains. This is the rationale or reason of what is called the chlorination process, and any person of ordinary capacity, upon reflecting upon the foregoing, will not fail to comprehend the method used through the aid of certain machinery, which we will presently describe. It may help to understand this subject if we remind the reader that each of the three chief processes of extracting gold from its matrix or stone or pyritous matter consists in bringing it into contact with some substance which has so great an affinity or liking for it that it is taken up or amalgamated, and then the amalgamating substance got rid of or the gold taken from it. Thus in the common stamper battery or grinding mill mercury is the amalgamat ing material, as all miners know, which takes up the gold. In smelting, matter containing gold is put by intense heat, often assisted by fluxes of various kinds, into a state of fusion, and then brought in contact with molten lead, which, like mercury, has an intense affinity for gold, and it is thus extracted-the lead in the one case and the mercury in the other being ultimately taken from the gold by evaporation, or as regards the lead by cupellation, which is in effect evaporation. As regards the third great process, viz., extracting by chlorine, we have explained upon what principle that is carried out, being, in fact, like the other two, merely making use of a substance which, by its great affinity, will seize hold of the gold and collect it, so to speak.
Of the three processes, the crushing and amalgamating with mercury, the smelting and amalgamating with lead, and the crushing and absorption by a solution of chlorine, each is suitable according to the way the gold is found in the stone or auriferous material. Rich pyrites or black sand, or concentrates, require smelting as a rule, because all the grinding, to whatever degree of fineness it may be carried, will not liberate all the gold from the iron and metals, so that mercury can act on it." Again, crushing by stampers or grinding in mills will be suitable where much of the gold is fairly coarse, and, as it is called, free in the stone. Arid chlorination comes in and is useful where gold is free in the stone, but is so very fine that in crushing in the ordinary way the mercury can't take hold of it but is carried away in the sludge or tailings. Chlorination also is useful in extracting the precious metal from concentrates, though in this case it may be found more suitable to sell them to the smelting works than to treat them by
chlorine at the mine.
Having thus described what may be termed the principles of chlorination, we now describe the appliances by which they are carried into effect. First, the stone is crushed dry, arid, as in the case of the iron-clad reef at Cargo where chlorination is carried on, by heavy steel rollers driven by steam power. Next the crushed stone is calcined in anordinary reverberatory calcining furnace to eliminate all the sulphur and arsenic which it is advisable to get rid of before treatment by chlorine. Then the calcined crushed stone is put into a large iron barrel about 8 ft long by about 3 ft in diameter* and lined with lead, because chlorine acts powerfully on iron as it does on gold and silver, but will not touch lead.

On page 25

A sufficient quantity of water is put in the barrel to make a thin sludge, then a quantity of chloride lime-that stuff much used as a disinfectant, and which is simply common lime saturated with chlorine gas-is put to the sludge, and upon that a small quantity of sulphuric acid. The barrel is then closed down air-tight, and made to
revolve very slowly. The acid acting on the lime evolves the chlorine, which is taken up by the water, and the chlorine solution takes up the gold in the stone. After some hours of the barrel revolving, the whole contents are turned out into
a cask or receptacle and allowed to settle. The clear liquor is then drawn off, and made to pass through a cask or vessel partly packed with common wood charcoal, which, as the auriferous chlorine solution passes through it, takes the gold
to itself; and upon tho charcoal being burned away, say in an iron pot, the pure gold remains. , This, then, is the chlorination process, which, we
think; our readers-even those quite unacquainted with chemistry-will clearly comprehend.
"He was always cold, but the land of gold seemed to hold him like a spell....Though he'd often say, in his homely way, that he'd "sooner live in Hell"....." ~~Robert W. Service~~

"When you live beside the graveyard, you can't cry for every funeral." - Russian Proverb

"Good judgement comes from experience, and a lot of that comes from bad judgement." ~~Will Rogers~~

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Re: recovery of gold from ores with chlorine in 1898

Postby Traveller11 » February 4th, 2013, 7:07 pm

Found this on the Clorox site:

What’s in Clorox® Regular Bleach?

Ingredients that make up one percent or more of the contents of a product by weight are listed in descending order of concentration. Those that make up less than one percent — like fragrances, dyes and preservatives — are listed in alphabetical order.


Water

Sodium hypochlorite

Sodium chloride

Sodium carbonate

Sodium hydroxide

Sodium polyacrylate

--------------------------------------------------------------------------------------

From this list and the preamble to it, we can deduce that sodium hydroxide (NaOH) makes up less than 1% of the weight of a solution of bleach. The sodium carbonate is slightly basic and would contribute to the high ph of a bleach solution, as well.

If one unit of added hydrochloric acid (HCl) would neutralize one unit of NaOH according to the following formula:

NaOH + HCl = NaCl + H2O

and, using regular 34% muriatic acid for HCl it was a one to one tradeoff (it may be necessary to dilute the HCl to a much lower percentage while trying to establish the needed volume), in a litre of bleach it might require as little as 2 to 3 millilitres of HCL to adjust the ph to the desired 7-7.5.

I must say I am quite surprised that less than 1% NaOH in a bleach solution is sufficient to maintain the ph of the bleach over 12.
"He was always cold, but the land of gold seemed to hold him like a spell....Though he'd often say, in his homely way, that he'd "sooner live in Hell"....." ~~Robert W. Service~~

"When you live beside the graveyard, you can't cry for every funeral." - Russian Proverb

"Good judgement comes from experience, and a lot of that comes from bad judgement." ~~Will Rogers~~

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Re: recovery of gold from ores with chlorine in 1898

Postby Barren Realms 007 » February 4th, 2013, 8:15 pm

If you have a PH meter and do some testing you will be surprised how little of an amount of solution it takes to change the PH.
Give a man a fish and you feed him for a day, teach a man to fish and you feed him for life.
You have to crawl before you can walk.
Patience is a virtue.
A man has got to know his limitations.

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Re: recovery of gold from ores with chlorine in 1898

Postby Traveller11 » February 4th, 2013, 9:23 pm

I'm patiently waiting for the ph meter I ordered on Ebay to arrive in the mail. I look forward to using it when it arrives.

Thinking over what you said, I looked again at one of the 1890's recipes for making a gold leaching chlorine solution. In this case, chlorine gas was introduced into a cylinder containing ground ore and water. Following, compressed air was introduced to a pressure of 60 psi, dissolving Cl2 gas in the water.

Once dissolved, the following happened:

Cl2 + H2O = HOCl + HCl

I had assumed the HCl produced would be of such low volume as to not alter the ph of the water (assumed to be 7) much below 5-6 but, I am not so sure anymore. Any ideas?

I know, from reading these older papers, that there was not much worry of the chlorine solutions dissolving iron (instead of gold) from iron oxides and, for this reason, I have to assume the ph of their chlorine solutions was not overly acidic. This, they claim, was one of the reasons for roasting ores; to convert iron and other base metals into oxides that would be impervious to their chlorine solution. Accordingly, it takes a very low ph (1-2?) to break the bond between the base metal and the oxygen.

This information is in contrast to an experiment I did with a sample of magnetite sand (Fe3O4). In a plastic container, I covered the magnetite with 1/2" of HCl. Within seconds, the HCl turned a dark amber colour; indicating I had made ferric chloride (FeCl3).
"He was always cold, but the land of gold seemed to hold him like a spell....Though he'd often say, in his homely way, that he'd "sooner live in Hell"....." ~~Robert W. Service~~

"When you live beside the graveyard, you can't cry for every funeral." - Russian Proverb

"Good judgement comes from experience, and a lot of that comes from bad judgement." ~~Will Rogers~~

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Re: recovery of gold from ores with chlorine in 1898

Postby butcher » February 5th, 2013, 7:55 am

Traveller11,

I am not sure what you are working towards here,or where you are at, but figured I would add a thought and some equation’s I stole from Wikipedia.

Chlorine in water forms Hypochlorous acid and hydrochloric acid
Cl2 + H2O <--> HOCl +HCl
Notice the above reaction is reversible
HOCl + HCl <--> Cl2 +H2O

In acid Hypochlorous acid forms chlorine gas and water (remember the Chlorine gas reacts with metals to form metal chlorides or escapes the solution)
HCL + HOCl -->H2O +CL2 (gas)

Light or metal oxide’s (like copper oxide can break down the chlorine also
2Cl2 + H2O ---light--> 4HCl + H2O
(If copper oxide we would get copper chlorides)

Common Bleach sodium hypochlorite NaClO is a sodium salt of Hypochlorous acid HOCl
There are a couple ways bleach is made electrolysis of salt brine or chlorine gas dissolved in cold sodium hydroxide, both will contain salt NaCl and be caustic with NaOH (the caustic helps to keep chlorine gas in solution dissolved in the water) household bleach sodium hydroxide is mostly water around 92 to 97% H2O.

Cl2 +2 NaOH --> NaCl +H2O + NaClO

NaOH can help to keep the chlorine in the water as a basic solution, and as we know acid and a metal base will form a salt of that metal:
HCl + NaOH --> NaCl + H2O

Sodium hypochlorite and acid can form chlorine gas:
NaClO + HCl --> NaCl + H2O + CL2 (gas)

Now we also need to consider the sodium hypochlorite is actually a basic solution of salt and sodium hypochlorite and sodium hydroxide so adding acid not only generates chlorine gas which reacts with metals or escapes as gas from solution, the reaction of the base and acid also brings pH closer to neutral as well as forming more salts and water in solution.

As we stated bleach can me mostly water which can dilute an acidic solution as well as act to adjust it pH toward neutral forming salts of our acid as the chlorine gases off or reacts with metals in solution to form metal chlorides.

Also if bleach is heated or evaporated from solution it can form salts of sodium chloride NaCl and sodium chlorate's NaClO3.

Bleach and hydrogen peroxide give off oxygen and form chlorine gas and salt water
4NaClO + 2H2O2 --> 4NaOH + 2Cl2 +O2
(again we see where this would be adjusting pH of our acidic solutions)

So with this we can see how these solutions not only dilute our acid but also can work to neutralize it forming a lot of salt in solution as the chlorine or other gases react or escape from the leach solution,

Many bleach solutions also dilute the leach.
Alternatives are dry bleach powders or using gases to do the same job without the side reactions.

Iron hydroxide is very un-reactive; to acids the red rouge powder is almost impossible to dissolve into acid, you can dissolve gold from this red powder and not dissolve the iron or put it into solution (as an iron chloride) even with acids as strong as aqua regia, roasting techniques are very important steps, your goal is to remove sulfides and other unwanted compounds and convert the oxide or iron compounds to the most desirable state for your next leach, if we are leaching iron first we want the iron to go into solution, but in a chlorination of acid solution where your trying to leach gold were too much iron in solution would re-precipitate the leached gold and put iron into solution ,with gold depending on conditions, we would not want the iron is a state easily dissolved.
How you roast can help quite a bit of what state the iron is in, also most of the soluble iron can also be leached before going after the gold.

But concentrating the of the ore down to a very high percentage of gold to ore or base metals is also important, as you not only will have more trouble and cost and waste, trying to process a low gold to ore or base metal ratio your loses will be higher and the likelihood of success is reduce with the more ore or base metals involved.

As I said I am not sure where you are at on this or if this will even help any.

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Re: recovery of gold from ores with chlorine in 1898

Postby modtheworld44 » February 5th, 2013, 3:29 pm

butcher wrote:Traveller11,

I am not sure what you are working towards here,or where you are at, but figured I would add a thought and some equation’s I stole from Wikipedia.

Chlorine in water forms Hypochlorous acid and hydrochloric acid
Cl2 + H2O <--> HOCl +HCl
Notice the above reaction is reversible
HOCl + HCl <--> Cl2 +H2O

In acid Hypochlorous acid forms chlorine gas and water (remember the Chlorine gas reacts with metals to form metal chlorides or escapes the solution)
HCL + HOCl -->H2O +CL2 (gas)

Light or metal oxide’s (like copper oxide can break down the chlorine also
2Cl2 + H2O ---light--> 4HCl + H2O
(If copper oxide we would get copper chlorides)

Common Bleach sodium hypochlorite NaClO is a sodium salt of Hypochlorous acid HOCl
There are a couple ways bleach is made electrolysis of salt brine or chlorine gas dissolved in cold sodium hydroxide, both will contain salt NaCl and be caustic with NaOH (the caustic helps to keep chlorine gas in solution dissolved in the water) household bleach sodium hydroxide is mostly water around 92 to 97% H2O.

Cl2 +2 NaOH --> NaCl +H2O + NaClO

NaOH can help to keep the chlorine in the water as a basic solution, and as we know acid and a metal base will form a salt of that metal:
HCl + NaOH --> NaCl + H2O

Sodium hypochlorite and acid can form chlorine gas:
NaClO + HCl --> NaCl + H2O + CL2 (gas)

Now we also need to consider the sodium hypochlorite is actually a basic solution of salt and sodium hypochlorite and sodium hydroxide so adding acid not only generates chlorine gas which reacts with metals or escapes as gas from solution, the reaction of the base and acid also brings pH closer to neutral as well as forming more salts and water in solution.

As we stated bleach can me mostly water which can dilute an acidic solution as well as act to adjust it pH toward neutral forming salts of our acid as the chlorine gases off or reacts with metals in solution to form metal chlorides.

Also if bleach is heated or evaporated from solution it can form salts of sodium chloride NaCl and sodium chlorate's NaClO3.

Bleach and hydrogen peroxide give off oxygen and form chlorine gas and salt water
4NaClO + 2H2O2 --> 4NaOH + 2Cl2 +O2
(again we see where this would be adjusting pH of our acidic solutions)

So with this we can see how these solutions not only dilute our acid but also can work to neutralize it forming a lot of salt in solution as the chlorine or other gases react or escape from the leach solution,

Many bleach solutions also dilute the leach.
Alternatives are dry bleach powders or using gases to do the same job without the side reactions.

Iron hydroxide is very un-reactive; to acids the red rouge powder is almost impossible to dissolve into acid, you can dissolve gold from this red powder and not dissolve the iron or put it into solution (as an iron chloride) even with acids as strong as aqua regia, roasting techniques are very important steps, your goal is to remove sulfides and other unwanted compounds and convert the oxide or iron compounds to the most desirable state for your next leach, if we are leaching iron first we want the iron to go into solution, but in a chlorination of acid solution where your trying to leach gold were too much iron in solution would re-precipitate the leached gold and put iron into solution ,with gold depending on conditions, we would not want the iron is a state easily dissolved.
How you roast can help quite a bit of what state the iron is in, also most of the soluble iron can also be leached before going after the gold.

But concentrating the of the ore down to a very high percentage of gold to ore or base metals is also important, as you not only will have more trouble and cost and waste, trying to process a low gold to ore or base metal ratio your loses will be higher and the likelihood of success is reduce with the more ore or base metals involved.

As I said I am not sure where you are at on this or if this will even help any.


butcher

I think Traveller11 is wanting a way to generate the wet chlorine gas,so he can use it for ore leaching.I'm not 100% sure on that so please don't quote me on it.

If this is the reason then this needs to be looked at more carefully,it's a piece of the page that Traveller11 posted the link for up in his second post on this page.

The full equation may be represented like this:
Cl2 + H2O --> HOCl + HCl
HOCl --> OCl– + H+
HOCl is, of course, the “active ingredient”. The OCl– is a bank, or reservoir of less active chlorine.
A common pool industry myth is that when HOCl is used in a pool only OCl– remains. In reality, when HOCl is used, OCl– immediately converts back to HOCl to maintain the percentage division mandated by the pH.
Although the actual reactions in water may be complex, a few illustrations in simplified language may help to describe what happens.
For example, if a pool contained 3 ppm total chlorine at a pH of 7.5, there would be about 1.5 ppm HOCl and 1.5 OCl–. If 1 ppm chlorine demand is introduced into the water, the myth would have us believe that as the demand is met, the HOCl is lowered to 0.5 ppm with the OCl– remaining at 1.5 ppm. Assuming the pH to be unchanged, what actually happens is that the total chlorine is lowered to 2 ppm, the HOCl is lowered to 1 ppm, and the OCl– is lowered to 1 ppm. This happens even though it may have actually been only the faster and more potent HOCl that satisfied the chlorine demand. The subsequent shift of 0.5 OCl– to HOCl is virtually instantaneous.


The demand in his case would be ores,so basically it would keep generating chlorine wet gas until all the OCl- was shifted to HOCl.

This is why I use Bleach in my GEOMOD cell.I rejuvenate the chlorine by adding pool chlorine tablets and the anode turns the chlorine into gas,which eats the metals.So in theory this cell could do the same for ores.I plan to try ore in my cell real soon.If you haven't read the full article yet you should it might give you better insite on what he's wanting to do.I've read and reread it about 5-6 times now.Hope this adds something to the forum that is of use!



modtheworld44
KNOWLEDGE IS POWER & POWER IS THE KEY TO UNDERSTANDING!

Traveller11
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Re: recovery of gold from ores with chlorine in 1898

Postby Traveller11 » February 5th, 2013, 3:58 pm

Hello modtheworld44

I think we are working towards the same end but have slightly different interpretations of what is happening. Looking at some of these articles from the 1890's, I do not believe that producing chlorine gas in the presence of ore is what they were doing. Yes, the one process fed Cl2 gas into the cylinder with ore and water in it but, it was then immediately dissolved in the water and transformed into HOCl and HCl. I also believe this did not lower the ph of the water significantly and, if it was 7 to start with, would only be slightly lower than this with the Cl2 dissolved in it.

In other words, I believe these old timers ended up with a strong solution of hypochlorous acid/sodium hypochlorite in water with perhaps minute amounts of Cl2 gas being released. The evidence I give for this is that they did not bother trying to remove iron oxides such as magnetite and hematite from the ores prior to leaching. If this were attempted with the normal HCl/Clorox formula proscribing large amounts of HCl added to Clorox, the solution would be so acidic, it would break the bonds of the oxides and put iron into solution instead of gold.

It seems the oldtimers were dissolving gold with an almost neutral solution of HOCl/NaClO in water that, except for strength, differed very little from swimming pool water.
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Re: recovery of gold from ores with chlorine in 1898

Postby modtheworld44 » February 5th, 2013, 5:09 pm

Traveller11 wrote:Hello modtheworld44

I think we are working towards the same end but have slightly different interpretations of what is happening. Looking at some of these articles from the 1890's, I do not believe that producing chlorine gas in the presence of ore is what they were doing. Yes, the one process fed Cl2 gas into the cylinder with ore and water in it but, it was then immediately dissolved in the water and transformed into HOCl and HCl. I also believe this did not lower the ph of the water significantly and, if it was 7 to start with, would only be slightly lower than this with the Cl2 dissolved in it.

In other words, I believe these old timers ended up with a strong solution of hypochlorous acid/sodium hypochlorite in water with perhaps minute amounts of Cl2 gas being released. The evidence I give for this is that they did not bother trying to remove iron oxides such as magnetite and hematite from the ores prior to leaching. If this were attempted with the normal HCl/Clorox formula proscribing large amounts of HCl added to Clorox, the solution would be so acidic, it would break the bonds of the oxides and put iron into solution instead of gold.

It seems the oldtimers were dissolving gold with an almost neutral solution of HOCl/NaClO in water that, except for strength, differed very little from swimming pool water.


Traveller11

The point I'm trying to make is this,back in the old days bleach wasn't called bleach.What did they call it I'm not sure,but if I had to guess chlorine .They didn't use hcl with it because there was no need.

What do you smell the secant you open a bottle of bleach?
What is your guess as to why they pressurized the tank?
Why didn't they need hcl?

These are all the questions I have asked my self.



modtheworld44
KNOWLEDGE IS POWER & POWER IS THE KEY TO UNDERSTANDING!


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