Cementing with Zinc didn't go as planned.

[4metals]

The flux we use is borax.

When melting karat scrap I have found an excellent flux to use is this flux

Standard Karat Thinning flux. Used to prevent beads in slag. Used on karat gold so as not to hang up beads in the slag.

1 part Anhydrous borax
1 part soda ash
1/8 part fluorspar

This flux will thin out the flux so it does not hold up beads. When a lot comes in for refining it should be melted with this type of flux to assure all of the values are in one place and not mixed in the slag. During this melt the Pin dip sample is taken before pouring the bar, then the bar is cleaned up for a weight and the sample is assayed. Some refiners have trouble with samples disappearing so they institute a policy of taking the pin sample and, while the lot is still in the furnace, quenching the sample to break the hot glass and cutting a piece about 2.5 cm long to serve as sample and reserve sample and the remainder of the pin goes back into the melt before it is poured. This assures enough sample is taken for assay and the balance of the value is in one place..... the bar!

When you put together a refining lot, all of the bars in the lot are melted together and poured into water to make cornflake shot which digests easier. Usually this can be accomplished without flux. Occasionally a small amount of karat remains in the crucible. This can, when the crucible cools, be removed and put in with the material to digest.

 

[4metals]

Do you suggest smelting the pure gold with the filter paper or do you advise against this? and if its smelted with filter paper is borax necessary?

The gold sponge is gently scooped off of the filter paper until it has mostly been removed, then the paper is carefully lifted and the remaining gold can be brushed off the paper into the crucible. This is often easier with dry filter paper.

Refined gold is typically melted without flux. This can be accomplished by adding the gold to the crucible first before the filter paper. Then, on top of the gold, the filter paper is placed so it can burn completely.

If using a gas furnace a cover on the crucible helps to keep the ash from flying out, not always necessary with induction furnaces but it never hurts.

The gold will melt and the paper will be fine ash when you remove the crucible cover. If there is any remnant of paper ash a trick is to add a small pinch of borax to the molten pool of gold. The borax will sizzle about and settle on the wall of the crucible. The purpose of this borax is to make a sticky spot where the ash can collect. Not a lot of borax, you only want enough to make a spot a few cm long. Then sparingly add pinches of niter (potassium nitrate) it usually is available as prills (little beads). This will sputter all across the molten pool and scrub the surface. It will collect any bits of ash from the paper and as a bonus oxidize any small amounts of copper on the gold's surface making it of a higher purity. Do not add too much niter, you will see the effect on the surface of the molten gold. Don't over do it. This process is a very old technique that was called "toughening" the gold.

After pouring the gold, the small patch of borax can be scraped off a cold crucible.

 

[4metals]

I do take blame for not noticing this step, a lesson that was learned the hard way.

A good sign is you are paying attention, that is how you learn. When your staff realizes you know what you are doing and what you are seeing makes sense to you, they will change their ways and respect you because you have shown them that you do have refining knowledge.

If you have any questions or want to get a second opinion about information you get from the local talent, feel free to post here and we will give our perspective freely.

 

[Nouran Alaa]

The gold sponge is gently scooped off of the filter paper until it has mostly been removed, then the paper is carefully lifted and the remaining gold can be brushed off the paper into the crucible. This is often easier with dry filter paper.

Refined gold is typically melted without flux. This can be accomplished by adding the gold to the crucible first before the filter paper. Then, on top of the gold, the filter paper is placed so it can burn completely.

If using a gas furnace a cover on the crucible helps to keep the ash from flying out, not always necessary with induction furnaces but it never hurts.

The gold will melt and the paper will be fine ash when you remove the crucible cover. If there is any remnant of paper ash a trick is to add a small pinch of borax to the molten pool of gold. The borax will sizzle about and settle on the wall of the crucible. The purpose of this borax is to make a sticky spot where the ash can collect. Not a lot of borax, you only want enough to make a spot a few cm long. Then sparingly add pinches of niter (potassium nitrate) it usually is available as prills (little beads). This will sputter all across the molten pool and scrub the surface. It will collect any bits of ash from the paper and as a bonus oxidize any small amounts of copper on the gold's surface making it of a higher purity. Do not add too much niter, you will see the effect on the surface of the molten gold. Don't over do it. This process is a very old technique that was called "toughening" the gold.

After pouring the gold, the small patch of borax can be scraped off a cold crucible.

When melting karat scrap I have found an excellent flux to use is this flux

This flux will thin out the flux so it does not hold up beads. When a lot comes in for refining it should be melted with this type of flux to assure all of the values are in one place and not mixed in the slag. During this melt the Pin dip sample is taken before pouring the bar, then the bar is cleaned up for a weight and the sample is assayed. Some refiners have trouble with samples disappearing so they institute a policy of taking the pin sample and, while the lot is still in the furnace, quenching the sample to break the hot glass and cutting a piece about 2.5 cm long to serve as sample and reserve sample and the remainder of the pin goes back into the melt before it is poured. This assures enough sample is taken for assay and the balance of the value is in one place..... the bar!

When you put together a refining lot, all of the bars in the lot are melted together and poured into water to make cornflake shot which digests easier. Usually this can be accomplished without flux. Occasionally a small amount of karat remains in the crucible. This can, when the crucible cools, be removed and put in with the material to digest.

Excuse my language barrier, what do you mean by pin sample?

Is it a sample taken from the smelt for fire assay and assesing the karat?

What we usually do in my refinery is we ***** each bar separately first by fire assay and then once we get back to the customer with the results from fire assay we smelt for granulation and a sample from the granulation step is taken and retested to ensure that the karat matches the first fire assay of each bar separately.

While smelting for the granulation process, the gold is mixed properly to ensure it's homogeneous.

 

[4metals]

What we call pin samples here in the USA and in most of Europe as well, is a glass tube that is sealed and it has a vacuum inside the glass cylinder. On one end is a bubble that is much thinner glass. When a melt is ready to pour, a pin tube is held in a holder made for it so the thin bubble is down. The glass is immersed into the molten. metal and you can feel a slight snap as the thin bubble melts first and the vacuum sucks up a small diameter rod of melt sample. The pin is quickly removed from the melt and once the metal sample cools, the glass is broken off with a small hammer and what remains is a very representative sample which can be cut into 2 cm segments and passed through a rolling mill to make a thin ribbon which can be cut into short pieces with a scissors for fire assay. Much easier than drillinng a bar and more representative of the melt. This is a website from one supplier who sells them, the company is Legend I am quite sure they are available in Europe as well.

 

[4metals]

The first picture is what the sample looks like when cut into smaller pieces. and the second photo is what the cut segment looks like when a rolling mill flattens it into a long thin ribbon.

 

[4metals]

whoops one more, this is the pieces when cut to assay. Simply pick up separate pieces to weigh into the lead for cupellation.

 

[Nouran Alaa]

whoops one more, this is the pieces when cut to assay. Simply pick up separate pieces to weigh into the lead for cupellation. View attachment 64115

This seems like a very convenient method.
The Sample pins are sold here in my country, I'll buy them and give them a try

 

[jakson]

Yes, Zinc is not the best solution in most cases,
it will however after its use have concentrated your values alongside other elements into a much more manageable size.


How did you arrive at these conclusions?


Is this a clear indication or may it be other metals?
As far as I understand, Hydrazine drops most all metals and as such is almost as Cementing with Zinc.


Comment in Bold inside quote

Can you describe the Hydrazine test for Gold in detail?

Carefully siphon off the liquid in the tanks, making sure not to disturb the sediments and add the sediments and liquid to a new and smaller tank.
Repeat after a day or two until you have concentrated the sediment to a thicker layer.
Dissolve the layer in HCl/Peroxide and drop with SMB, Ascorbic acid, Oxalic acid or other preferred method.

As to turbidity, it may be suspended particles, add Sulfuric acid and heat the solution to a simmer, this should agglomerate the particles.

Hello sir, I put sulfide mineral soil in aqua regia, after one day I filtered the solution and neutralized the excess nitric and added sodium metabisulfite to the solution and half an hour later I applied zinc powder, a black deposit accumulated on the top of the human body. I cleaned the stainless steel bowl, then I put them in nitric acid, the sediment did not dissolve in nitric acid, then I washed it with water and put it in hydrochloric acid, the sediment did not dissolve in hydrochloric acid, then I melted it with air gas, it had a white glow when it melted, and it was scattered in the plant and It did not turn into metal and brown slag was formed. Can you find my problem? Sorry, the explanation is too long. I am not in a good financial situation. For several months, I have been pouring dirt in Aqua Regia to get gold, but I have not succeeded.

 

[Yggdrasil]

Hello sir, I put sulfide mineral soil in aqua regia, after one day I filtered the solution and neutralized the excess nitric and added sodium metabisulfite to the solution and half an hour later I applied zinc powder, a black deposit accumulated on the top of the human body. I cleaned the stainless steel bowl, then I put them in nitric acid, the sediment did not dissolve in nitric acid, then I washed it with water and put it in hydrochloric acid, the sediment did not dissolve in hydrochloric acid, then I melted it with air gas, it had a white glow when it melted, and it was scattered in the plant and It did not turn into metal and brown slag was formed. Can you find my problem? Sorry, the explanation is too long. I am not in a good financial situation. For several months, I have been pouring dirt in Aqua Regia to get gold, but I have not succeeded.

First Sulfides needs to be roasted first.
Next we do not neutralize Nitric we deNOx or decompose as SMB needs to be done in an acidic milieu.

No need for Zinc after SMB.
If you really want to use Zinc there will be no need for SMB.
Do you have an assay?
Or at least test for Gold with Stannous.
I'm afraid you are just wasting time and money.

You really need to study more.
I'm on night shift so I haven't time to post more now.

 

[jakson]

First Sulfides needs to be roasted first.
Next we do not neutralize Nitric we deNOx or decompose as SMB needs to be done in an acidic milieu.

No need for Zinc after SMB.
If you really want to use Zinc there will be no need for SMB.
Do you have an assay?
Or at least test for Gold with Stannous.
I'm afraid you are just wasting time and money.

You really need to study more.
I'm on night shift so I haven't time to post more now.

Thank you for your answer, I'm not in a hurry, please answer whenever you have time. There are many disturbing metals in the Aqua Regia solution, and as long as metabisulfite and zinc powder do not mix and hydrogen sulfide gas is not released, no metal precipitates from the solution. I tested with zinc powder. It doesn't work alone. Meanwhile, I took tin chloride test solution, first it turns pale purple and then brown

 

[Yggdrasil]

Hello sir, I put sulfide mineral soil in aqua regia, after one day I filtered the solution and neutralized the excess nitric and added sodium metabisulfite to the solution and half an hour later I applied zinc powder, a black deposit accumulated on the top of the human body. I cleaned the stainless steel bowl, then I put them in nitric acid, the sediment did not dissolve in nitric acid, then I washed it with water and put it in hydrochloric acid, the sediment did not dissolve in hydrochloric acid, then I melted it with air gas, it had a white glow when it melted, and it was scattered in the plant and It did not turn into metal and brown slag was formed. Can you find my problem? Sorry, the explanation is too long. I am not in a good financial situation. For several months, I have been pouring dirt in Aqua Regia to get gold, but I have not succeeded.

I expect you now has had an assay done, right?
If not, what you are doing now is not only dangerous, but even without purpose.

Did you at least do a Stannous test before adding SMB or Zinc.

I recommend you to study these links:

We ask our new members to do 3 things.
1. Read C.M. Hokes book on refining jewelers scrap, it gives an easy introduction to the most important chemistry regarding refining.
It is free here on the forum: https://goldrefiningforum.com/phpBB3/viewtopic.php?f=54&t=19798
2. Then read the safety section of the forum: https://goldrefiningforum.com/forums/safety.47/
3. And then read about "Dealing with waste" in the forum: https://goldrefiningforum.com/threads/dealing-with-waste.10539/

Suggested reading:
https://goldrefiningforum.com/forums/the-library.101/
https://goldrefiningforum.com/threads/when-in-doubt-cement-it-out.30236/
https://goldrefiningforum.com/threa...le-read-this-before-you-post-about-ore.33333/


Forum rules is here.
https://goldrefiningforum.com/threads/gold-refining-forum-rules.31182/

 

[Yggdrasil]

Thank you for your answer, I'm not in a hurry, please answer whenever you have time. There are many disturbing metals in the Aqua Regia solution, and as long as metabisulfite and zinc powder do not mix and hydrogen sulfide gas is not released, no metal precipitates from the solution. I tested with zinc powder. It doesn't work alone. Meanwhile, I took tin chloride test solution, first it turns pale purple and then brown

If Zinc do not work, there are too much Nitric in the solution or maybe no metals dissolved?
It will drop all metals dissolved as long as thew pH are high enough or low enough, ie the solution is not neutral.
Are there anything of value in the ore at all?

 

[jakson]

If Zinc do not work, there

If Zinc do not work, there are too much Nitric in the solution or maybe no metals dissolved?
It will drop all metals dissolved as long as thew pH are high enough or low enough, ie the solution is not neutral.
Are there anything of value in the ore at all?

Hello, before adding metabisulfite, I took a stannous test, first it turns pale purple and after a few seconds it turns brown. I have completely read the free version of Hook's book, I removed nitric acid with sulfamic acid at 70 degrees Celsius. There are many disturbing metals in the ore, which disturbs the performance of metabo and zinc powder. Fortunately, with the combination of metabo sulfite and zinc powder, the metals are precipitated from the solution, but I have problems in the stages of purifying the gold powder and melting it.

 

[Yggdrasil]

Hello, before adding metabisulfite, I took a stannous test, first it turns pale purple and after a few seconds it turns brown. I have completely read the free version of Hook's book, I removed nitric acid with sulfamic acid at 70 degrees Celsius. There are many disturbing metals in the ore, which disturbs the performance of metabo and zinc powder. Fortunately, with the combination of metabo sulfite and zinc powder, the metals are precipitated from the solution, but I have problems in the stages of purifying the gold powder and melting it.

If the Stannous fades and become brown it means that there are still Nitric in solution.
Excess Oxidizer (Nitric) may lead to the Zinc working but still redissolve the Zinc and cement and present no result.

But seriously answer my questions now.
Have you had an assay?
Have you roasted your ore first?
By using Zinc you drop all metals. It then need to be refined again.
Anyway the best would be to use Copper in stead of Zinc as Copper will only drop the precious metals not all the other "junk".

But get an assay first so you know what you are dealing with.
By the way what do you do with tour waste?

 

[jakson]

اگر Stannous محو شود و قهوه ای شود به این معنی است که هنوز نیتریک در محلول وجود دارد.
اکسید کننده اضافی (نیتریک) ممکن است منجر به عملکرد روی شود، اما همچنان روی و سیمان را دوباره حل می کند و نتیجه ای ندارد.

اما حالا به سوالات من جدی جواب بده.
آیا آزمایشی انجام داده اید؟
آیا ابتدا سنگ معدن خود را برشته کرده اید؟
با استفاده از روی تمام فلزات را رها می کنید. سپس باید دوباره اصلاح شود.
به هر حال بهترین کار این است که از مس به جای روی استفاده شود زیرا مس فقط فلزات گرانبها را از بین می برد و نه همه "آشغال" های دیگر.

اما ابتدا یک آزمایش انجام دهید تا بدانید با چه چیزی سر و کار دارید.
به هر حال با زباله های تور چه کار می کنید؟

I have roasted the ore, but still much sulfur is liberated in the Aqua Regia solution, which makes cement with iron or copper difficult, only hydrogen sulphide gas can precipitate the metals.

 

[Yggdrasil]

من سنگ معدن را بو داده ام، اما هنوز مقدار زیادی گوگرد در محلول Aqua Regia آزاد می شود که سیمان را با آهن یا مس می شکند، فقط گاز سولفید هیدروژن قادر به رسوب دادن فلزات است.

English if you want answers.

 

[jakson]

English if you want

English if you want answers.

Excuse me I edited the post

 

[Yggdrasil]

I have roasted the ore, but still a great deal of sulfur is liberated in the Aqua Regia solution, which breaks down the cement with iron or copper, only hydrogen sulphide gas being able to precipitate the metals.

Then my question is how do you deal with the H₂S?
It would be better to complete the roasting as H₂S is an very unforgiving and lethal gas, probably as bad as HCN.
Better to deal with the SO₂ from roasting, it is unpleasant but not lethal in the same way.

I have asked a few questions to you and you are either avoiding them or do not want to answer.
It is much easier to help people that give the information needed voluntarily, instead of having to drag it out of them.
So can you please answer my questions now?

 

[jakson]

Then my question is how do you deal with the H₂S?
It would be better to complete the roasting as H₂S is an very unforgiving and lethal gas, probably as bad as HCN.
Better to deal with the SO₂ from roasting, it is unpleasant but not lethal in the same way.

I have asked a few questions to you and you are either avoiding them or do not want to answer.
It is much easier to help people that give the information needed voluntarily, instead of having to drag it out of them.
So can you please answer my questions now?

Yes, if you have any questions, please let me know. I don't hide any answers. I do the work outdoors. Hydrogen sulfide gas, which is created from the combination of sodium metabisulfite and zinc powder, does not harm me.