Hcl Acceptable strength

Gold Refining Forum

Help Support Gold Refining Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

martymcfly

Well-known member
Joined
Jul 20, 2013
Messages
64
Location
Scotland
Ive been looking locally for a cheap source of hcl and as everybody knows brick cleaner is the stuff, My only problem is the strongest stuff i can find is 17-%20%.
I plan on using this for ap/ar so my question would be is this too weak to work and if so could i use the equilibriam method to bring this up to an acceptable strength, And also if i did use the equilibriam method what would be the final strength.


many thanks
 
McFly,

It should be fine, but you must also be aware of the following:

1) The volume of your solutions will increase due to the extra water in the acids ( it takes a certain amount of acid at 30%+, and thus it requires more acid at the lower concentrations).

2) There may be unwanted additives in many of the 'lower proof' acids. Check the manufacturer's MSDS on the product when possible and avoid products with inhibitors and other new fangled additives.

Steve
 
The best source I have for HCl (Hydrochloric acid) is from swimming pool supply shops as Muriatic Acid 37% which is full strength for us.
Only pay around $4,00 USD per gallon for it and it has no additives. I've been using it for years with no problems.
 
Thanks guys,

I can get 5 litres of 17-20% for £10 here but had concerns over the strength. I was thinking of trying this http://www.youtube.com/watch?v=jv1Ms6Subg4 to purify it but cant find an equation to work out what strength i would be left with.

Also could this method be used to make an infinate supply of hcl by simply replacing the distilled water with fresh every week or so? I would think not Since surely the gas is being used up from the original hcl.
 
So after waiting a week or so with this method (in the video) the HCl would be around half the strength of your original muriatic acid, and both containers in the larger tub would be about that strength, the one of the original muriatic (reduced in strength, and the one the water which absorbed the HCl fumes (which would be more purer).
That method would work when using 32 % muriatic acid but not with your acid, see below.

He used about 10 molar acid and ended up with about 5 molar acid in both containers.
His goal was to get a more pure HCl from a less pure HCl, which also reduced the strength of his acid.

We do not need pure acid, as long as your acid does not contain inhibitors or other major contaminates, regular muriatic will work just fine, if it is diluted it can be heated (while dissolving metals or just by itself) to concentrate the acid if heated to drive off water, if without metals you could concentrate the acid to about 20% HCl and about 80% water that is where HCl azeotropes at normal atmospheric pressure, so normal evaporation would not make it any stronger.

HCl sold as muriatic is just fine for refining the minor impurity is no problem, muriatic is normally sold as about 32% HCl, note this is stronger than azeotropic acid, this is why when you open a jug it fumes off HCl gas (the acid is trying to get back to the 20% azeotrope, this is also why what you see in the video works the HCl gas fumes are absorbed by the distilled water in the tubs.

This muriatic acid sold as concrete cleaner or for swimming pools may have a little iron contamination, coloring it yellow from the process in its manufacture, but that is no harm in our procedures.

Hydrogen chloride gas (HCl) is a clear gas, when this gas is absorbed into water it makes Hydrochloric acid (HCl acid),
HCl (g) + H2O(l) --> H3O + Cl
(Or HCl acid, also called muriatic acid).

Muriatic is just another name for this acid, the brick cleaner HCl is not of High purity like reagent grade but with what we are using it for it is pure enough, the little iron or other minor impurity does not effect the outcome of our processes, that is as long as there has not been inhibitors added to the HCl.

We Can make HCl gas and dissolve it into water, to make HCl acid, NaCl sodium chloride (salt) and H2SO4 sulfuric acid heated gives off HCl gas, distilling these fumes into distilled water will give us HCl acid, the water will absorb these gases until it gets to be about 20% HCl and about 80% water the azeotrope of HCl at normal conditions, which is about as concentrated as we could make it under these conditions.

If the acid is lower than 20% HCl, as you say your acid is, you would not have much luck with the reaction in the video, why?, because your acid will not fume of HCl gas off as it is below azeotropic HCl concentration, notice he was using 32% impure HCl which will fume on its own, and these fume were absorbed by water in the other container of water, since his acid was above azeotrope his method worked.

One way you could get more pure acid and a higher concentration would be to heat your dilute solution and concentrate it up to 20% then, put this 20% HCl into a distilling rig to purify it by distillation, (not needed in our case but if you want it pure), continue heating to drive off HCl gas from the 20% acid now at azetrope, distilling your acid now 20% impure acid to get more pure 20% HCl in the receiver flask, but you would not be able to get the acid any stronger, in fumes or in the acid mix, you will need a glass distilling rig, which could be a laboratory equipment, or you can make a homemade distilling rig using a glass coffee pot homemade Teflon seal-able lid (turned on lath or a drill and cut to tight fit) and a hose suitable for the acid, coiled in a bucket of ice water to make the condenser, with the end of your hose would bubble HCl gas into a small amount of distilled water.
For HCl a lab round or flat bottom lab flask and a rubber cork and hose would also work as the distilling rig (but for nitric acid do not use rubber corks they melt to a gooey jell).

I can distill from an old gallon pickle jar using a sand bath and using proper procedures.
I like the wide mouth of the jar. You could also use a beaker, just cut your Teflon lid to fit it tight, this lid will need to be taped with Teflon tape for a good seal, electrical tape on the outside, and cloth tape, I hold the lid on tight with a wire tie down, here is a description of how I make nitric acid by distilling H2SO4 a nitrate salt and DE-plate gold flakes from copper pins plated in gold, in one operation of distilling in the pickle jar, the byproduct is also saved which also makes an electrolyte I use in a cells (to recover silver from silver soldered copper, but that is another story) so basically I have no waste from this.

In the link below I describe a process using a home made pickle jar distilling rig and give some safety advice in its use, since then I have also made some other distilling rigs made of old second hand coffee pots like in the picture by cutting Teflon lids to fit them.

To kill two birds one stone, to get gold, nitric acid, and copper sulfate electrolyte, all in one process:
http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?f=38&t=6199


Off topic:
For miners in Australia I found this tidbit interesting, and we thought those wood eating pests were only good for eating up our houses, maybe I will think twice before trying to poisoning them, and think more about following them around.

A recent study by Australian scientists found that termites have been found to excrete trace deposits of gold. According to the CSIRO, the termites burrow beneath eroded subterranean material, which typically masks human attempts to find gold, and ingest and bring the new deposits to the surface. They believe that studying termite nests may lead to less invasive methods of finding gold deposits.
 

Attachments

  • $(KGrHqZ,!q4FDmR6ijbiBRCDMOJPm!~~60_57.jpg
    $(KGrHqZ,!q4FDmR6ijbiBRCDMOJPm!~~60_57.jpg
    555.2 KB · Views: 213
  • Picture%204.png
    Picture%204.png
    76.6 KB · Views: 213
I do use concrete cleaner HCl without any problem. Mostly with 17-20% HCl but sometimes I used even 10% HCl strength and again it was working quite good.
 
Back
Top