Help building a Aqua Regia System

[sohan]

I want to build a aquaregia system for refining gold jewellery of 18k to 23k ranging from 500gms to 2kg. I generally cast a bar and than make a strip roll and put in aqua regia solution and than manual stir, than filter and than precipitate. There is loss of gold dissolved solution in manual process.
I was thinking if any one has build a system could help me build one. I have borosilicate beakers.
Components i need help regarding :
● stirrer and heater (now i am using a induction with iron plate)
● pump to transfer AR solution for filtering.
● pump to tranfer gold precipitated solution with gold powder for filtering.

I have seen systems available in market starting from 5,00,000 Indian Rupees. I am thinking of building a system myself as i like DIY's and save some money. Any help, suggestions or advice would be helpful.

 

[4metals]

What is the percentage of Silver in your alloy?
Is nitric acid available and affordable in your area?


Your answer will determine the best path for you to follow.

 

[sohan]

What is the percentage of Silver in your alloy?
Is nitric acid available and affordable in your area?


Your answer will determine the best path for you to follow.

5-10% of silver and nitric is available 3000 INR for 40 litres

 

[4metals]

Your losses were probably because of Silver Chloride in aqua regia. Especially if you approach 10% Silver.

I think your best bet will be inquartation and double parting with nitric acid. That can get your purity in excess of .995 without dissolving the gold in aqua regia. And you will recover all of the Silver you need to add for the process plus all of the Silver in the alloy.

The benefit of nitric parting is it can be done in stainless steel so no glass breakage worries. We have had members here measuring gold refined this way by XRF and getting results of .999+ (specifically a refiner in Vietnam).

The volumes you are working with can be easily transferred by vacuum and the final rinses with Distilled Water can be easily lifted and poured.

 

[4metals]

This approach is easy for a DIY refiner. Your most important equipment will be your melt furnace which you have, a good fume hood and a strong vacuum system. A scrubber will be beneficial if you are in an inner city location.

 

[4metals]

This thread will be useful to you. His feed had a high Silver content and he originally wanted to use aqua regia. He tried both aqua regia and nitric acid and decided in the end to use nitric. It was a good thread because he got back to us with his results and was able to see it both ways.