Determination of Gold in Antimony Ores by Hydroquinone Volumetric Method with Antimony Tartrate as Complexing and Masking Agent

The traditional method of determining gold in antimony ores commonly includes sample digestion by aqua regia, preconcentration of gold by activated carbon, and measurement by hydroquinone volumetric technique. The traditional method suffers from the high contents of antimony, sulfur, arsenic, and mercury. Sulfur, arsenic, mercury, and carbon can be removed by stepwise heat, but antimony cannot be removed. In this study, tartaric acid is added to eliminate the interference of antimony. Adding tartaric acid to aqua regia during sample digestion can prevent proteolysis of antimony compounds as the acidity or temperature decreases. This step can ensure that the antimony quantity is less than 0.3 mg after the ashing of activated carbon that has adsorbed gold. After being ashed, tartaric acid is again added in aqua regia to dissolve gold, eliminating the interference of antimony on gold during hydroquinone volumetric determination of gold. The proposed method suggests adding tartaric acid at the sample digestion stage is simple and rapid relative to the method of antimony elimination by hydrobromic acid and hydrochloric acid. The relative standard deviation of natural sample analysis is less than 5% and standard-addition recovery is 92.0%-107.0%.