presipitation questions

[goldencad]

Hello, Her is a topic i know has many answers!!! But i need to make some forward movement!

1. so2 (sulfur dioxide) for gold
2. Platinum ???
3. pladadium
4. Rhodium

I would like to know the sucess rates for reducing nitric with Urea and what type?
is there another device or easier way to reduce nitric on a medium scale?

You all have answered these questions a thousand times! but once again please! I use recovery from mineing not scrap as a source for my metals.

I use a nitric wash first to remove silver base metals etc and drop my silver with hcl

I next would use cold aqua regia for gold

I next would use hot aqua regia for plat.

I'm not sure for a which places for pladium extraction Nitric stage or hot ar

Thanks for some help

Carl

 

[nickvc]

Carl im no expert on PGMS but i think the palladium will dissolve in the nitric along with the base metals and silver, the platinum i think will partially dissolve in the cold AR. Read Hokes book it covers all these subjects it will save you much time and give you a better understanding of the refining processes.

 

[goldsilverpro]

I would like to know the sucess rates for reducing nitric with Urea and what type?
is there another device or easier way to reduce nitric on a medium scale?

If you don't use an excess of nitric, there is no need for urea or boiling down. I've been preaching this from day one.

Cold or hot, you're going to dissolve some Pt.

 

[goldencad]

Do you have a technique to determine how much nitric to use in ar. I have heard before that you do not like excess nitric. Do you have some report or something that you have done to share your experience available, it would sure be a great help.

Do you have any suggestions on recovery of the pt dissolved in nitric or cold ar, or a way to limit its loss.

Carl

 

[Harold_V]

Do you have any suggestions on recovery of the pt dissolved in nitric or cold ar, or a way to limit its loss.

For all practical purposes, there is no reason to even consider that you might lose values when they are found sparsely in solutions. Also, take note, platinum group metals, unlike silver and gold, can not be recovered by conventional methods from dilute solutions, and it's usually not cost effective to reduce the solutions until values can be recovered. However, there is a simple way to extract them.

You have been handed a bit of advice that is worth its weight in gold. Read Hoke's book. You can spend a week asking questions that have already been answered, not only here, but in the book. If you find yourself involved with precious metals, as you suggest, there is no reason you can provide that is good enough to have me believe you don't have need to read the book. Get after it as quickly as you can. Once you start reading, you will understand why it is being promoted as it is.

Harold

 

[lazersteve]

Hoke states that 30 mL of 70% HNO3 + 120mL of 36% HCl will dissolve 31.1 grams of gold.

This works out to roughly 1 mL HNO3 + 4 mL HCl is needed per gram of gold. Of course, you'll want to add an equal volume of water to the solution also. The water gives the dissolved metal salts somewhere to go as they are formed and also reduces the off gassing by adsorbing some of the gases produced as by products or the reaction (NOx and Chlorine). Lastly the extra water prevents your expensive acids form being boiled away as the reaction proceeds.

Steve