# what is the best reducing agent to precipitate gold



## Anonymous (Jul 12, 2009)

hi everybody 
so i use ferrous sulphate feso4 but i have some problem in my solution (gold is contamined by sulfate ) .what is the best and esiest reducing agent :

*sodium nitrite 
*fesso4
*hydroquinone
*sulfite sodium
*smb
*oxalic acid 

thanx for help.


----------



## 4metals (Jul 13, 2009)

If refining gold was that simple, everybody would do it! The answer to your question is it depends. To get a good answer you need to answer a few questions. 
1. What was your source of gold? Electronics, ore, jewelry?
2. What did you digest it in? How much scrap and how much acid.
3. How much ferrous sulfate did you add?
4. How do you know your gold is contaminated with sulfates? 

Answer these questions and you'll get better answers.


----------



## Anonymous (Jul 13, 2009)

ok . this is a very good question : 

i prepare aqua regia 3:1 hcl (22%) hno3(42%) color (yellow orange).
* so my source gold is ores . 
*i use a lot of aqua regia 1 liter per 100 g ore .(of couse eliminte hno3 by evporation or using urea).
and i prepare sulfate solution with addittion a littel hcl until the color change(apple green) then i add a lot of(20g feso4 per 100g ore) in mother solution.


----------



## 4metals (Jul 13, 2009)

How about some history of the ore? Is it a concentrate, black sands, do you know how much gold you're going after? Generally aqua regia is used for metals based material, as in placer nuggets. Not necessarily high grade but high metals percentage. Depending on the matrix of the ore there may be salts interfering with the action of the acid. Have you successfully done this process with aqua regia in the past? Have you roasted the ore? 
Your technique to make the ferrous is correct and you are using a lot of acid for 100 grams. What do the insolubles look like when you filter before evaporation or urea?


----------



## Harold_V (Jul 13, 2009)

Considering the source of your solution, I question if you have any gold to recover. Removing values from ores with AR isn't the best approach, especially if the ore is of low value. 

If your solution is yellow/orange after being exposed to the ore, I expect you have iron in solution, not gold. 

Does it test positive with stannous chloride? If not, you have the answer.

Harold


----------



## Anonymous (Jul 14, 2009)

i dont know . but suposons this ores contains very very low grade of gold ,they are any method or i must use cyanidation (cip carbon in pulp or cil carbon in leach). 

thanks.♥


----------



## 4metals (Jul 14, 2009)

Acid refining is way too expensive for ores, unless we're talking concentrates. Search for leach procedures on the forum and you'll be better informed.


----------



## Harold_V (Jul 14, 2009)

Carbon isn't a requirement. Assuming you are successful in extracting values by one of the leach systems, you can effect a good recovery using zinc flour (dust), which is exactly what I'd recommend. Dealing with carbon requires a stripping and reactivation system, or incineration. The carbon is generally quite hard and does not incinerate well.

Harold


----------



## Anonymous (Jul 14, 2009)

ok thank you very much for this informations .


----------

