Texas said:
Hi Harold, well. gold is not precipitated
To practice, I start to work about 4 grams of gold with copper and other impurities, including lead and tin:
step by step:
1-treatment with nitric acid and heat for remove base metals
2-rinse and wash
3 -more nitric with heat to boil
4-rinsing and washing
5-wash and rinse with hcl
Step 5---rinse with hcl. That is a mistake. Regardless of what you may read or hear, do NOT go from nitric to hcl without incineration. The best rinsing won't totally eliminate nitric, so you risk dissolving some gold.
6-dissolved with aqua regia, at this point, it seems that copper had been trapped in gold, for the aqua regia is dyed green
7- add 5oz sulfuric to 10 oz of aqua regia :shock:
Say what?
At the most, ten drops of sulfuric would have been adequate. I'd likely have used only a couple. As for AR----you used enough to dissolve two ounces of gold or more. That, too, is a mistake. Remember, you must eliminate any unused nitric before recovering the values. Using too much is not a wise thing to do.
8 - warmed to make a syrup and added hcl and not bubbling brown!
Likely because you have not evaporated enough, but in this case you should stop the process and recover the values by other means.
For the amount of gold you have in solution, at best, you would have only 50 ml of gold chloride. I expect you have a great deal more.
I'm tired, frustrated, angry ... I've refined fine gold 1 / 10 oz,
and still again I was wrong by not following to Hokes literally,
What do I do with my solution?........
As long as you haven't discarded anything, you still have the gold. The valuable lesson that I hope you've learned is that you should read Hoke before trying to refine. A huge amount of your trouble would have been avoided by doing so. Of uppermost importance is that you gain the understanding that you must allow acid to do its work. Never use more than is required, and allow time for that which is applied to dissolve the metals involved. An excess of acid may work faster, but you'll lose more time attempting to eliminate the acid than the time you'll gain by using too much.
Right now I expect your solution is very acidic---may have a pH of 1. It will digest some copper that will go to waste, but if this mess was mine, I'd filter the solution, making sure there's no solids involved, then I'd cement the traces of values using copper. The recovered gold will require re-refining, but you will have eliminated the majority of the garbage that got included with the values, and you'll have effectively eliminated all of the excess acid.
Keep in mind, one ounce of nitric mixed with four ounces of HCl will dissolve a troy ounce of gold. Use a corresponding amount of AR when you dissolve small amounts of gold, so you don't have a huge amount of nitric to expel. You are far better served to use too little, then add more, that to use too much, then try to eliminate the excess.
Using ferrous sulfate, an ounce of ferrous sulfate will precipitate an ounce of gold, although using a small excess is good insurance, and causes no harm.
Harold
, I read Hokes, and her says, if use excess of sulphuric, the solution gets too much acid, ad that prevents the gold carry down :shock: ....Help!!! now what I doing ?
