Mobile Nano-Filtering

How to wash

Leach Liquid Conditions

The Gold must be in a gold chloride form

Liquid must be clean and contain no solids/dirt or fine particles

pH must be in the range of 2.5 to 4

ORP must be in the range of 900 to 1200

We suggest that the salt content be between 50 to 200g/L to help keep the gold in solution (If silver is present in liquid it must be close to 200g/L or it will not stay in solution)

The pregnant leach liquid should be stored in a dark container, light can precipitate the gold out of the solution

The leach liquid should be shipped quickly after being made to ensure we can test it before the gold falls out of the solution


Suggestions on Leaching the concentrate with the chloride-hypochlorite solution:

Keep a 1:5 (kg:L) solid to liquid ratio

Concentrate should be ground to 150 mesh or less

Mix the solution and concentrate to keep solids in suspension and not on the bottom of the tank 

Mix the solution and concentrate for at least 2 hours

Need to monitor the pH, ORP and Temperature and keep them in the range of 3-4, 1000-1200 and 20 C – 35 C respectively

If the pH increases above 4:

Add HCL to lower the pH

If the pH decreases below 3:

Add NaOCL to raise the pH

If the ORP decreases below 1000

Add NaOCL to raise the ORP 


Tips

Always make sure you have proper ventilation when making the chloride-hypochlorite solution, if you add the HCL to quickly to the solution, localized chlorine gas will come up from the solution.


If the concentrate has a high sulfide concentration, it will lower the pH and outgas the chlorine gas in solution, to counter act this start the solution at a higher pH between 6-7. The sulfides will turn to sulfuric acid and lower the pH and increase the ORP to the required range to leach the gold from the concentrate. 


Keep the pressure of the leach solution above 1 atm to maintain best leaching conditions and as little outgas as possible.