CONTROL OF LEAD NITRATE ADDITION IN GOLD RECOVERY

摘要

A method for controlling the extraction of gold from a goldore by the cyanidation process in which a leaching step includingthe addition of a lead compound, which is typically lead nitrateor other lead salt, is used. In order to maintain stableconditions in the leaching process, and to use the leachingreagents efficiently, an analysis step is used to monitor theconcentration of thiocyanate in the cyanidation step. This valuehas been found to be directly related to the rate of addition ofthe lead compound in the pre-leaching or leaching step. Further,the rate of addition of lead compound is also directly related toboth the time required for, and the efficiency of, thecyanidation step. By establishing a target value, and apreferred range, for the thiocyanate concentration based on theproperties of the ore being processed, optimal extractionconditions can be established in the leaching process andmaintained by monitoring the thiocyanate concentration. By theuse of an automated potassium permanganate titration procedure asthe analysis step, the thiocyanate concentration can be measuredon line with only a short delay.