How to Test Gold Content in Leaching Solution Using Zinc Wire？

A customer from India recently purchased our leaching chemicals to perform gold leaching tests. He asked how to determine when the gold content in the pregnant solution has reached its lowest point, so he can begin the next batch.

I consulted our engineer, and the recommendation was to use zinc wire testing. Below is the step-by-step testing procedure:

Step-by-Step Zinc Wire Testing Process
Step 1
Take 1000 ml of the pregnant solution. Adjust the concentration of the leaching agent to 15–20 parts per 10,000. Heat the solution to boiling, then add 5–10 grams of zinc wire (zinc content ≥ 99%).

Step 2
Add 10–20 ml of standard silver nitrate solution to the boiling mixture. Continue heating for 10–15 minutes. After heating, remove the zinc wire and rinse it thoroughly with clean water.

Step 3
Place the rinsed zinc wire into a dilute sulfuric acid solution (prepared by mixing 20 ml of concentrated sulfuric acid with 200 ml of clean water). Wait for the zinc wire to fully dissolve. Then, boil the solution to precipitate the gold mud.

Step 4
Once the gold mud settles, pour off the dilute sulfuric acid solution and rinse the residue, leaving only the gold mud. Add 20–30 ml of concentrated sulfuric acid and boil for 1–2 minutes. This final step helps purify the gold. Stir or shake gently to allow the gold particles to clump together.

 

Customer Follow-Up
I have already shared this procedure with the customer. He has purchased zinc wire locally and will send me a video of his testing process next week.

He also mentioned that if this test is successful, he plans to place a new order.

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