Determination of Total Mercury in Gold-loaded Carbon by Solid Mercury Analyzer

Gold-loaded carbon has a strong adsorption ability of mercury, which will result in the pollution of the gold extraction process and reduce the absorption of gold by activated carbon. Therefore, it's necessary to determine the mercury content in gold-loaded carbon to monitor the hazards of mercury. In the available method for Hg determination, the carbon matrix should be removed by high temperature ashing, but the mercury is readily lost due to volatilization. Total mercury can be directly determined by Solid Mercury Analyzer without sample preparation and the addition of other reagents. The best pyrolysis conditions for gold-loaded carbon are defined that air flow is 0.8-1.2 L/min, evaporation temperature is 680-740℃, and the recovery of mercury is up to 99%. Carbon matrix in samples will be changed into carbon dioxide and the interferences of carbon dioxide can be automatically eliminated by Solid Mercury Analyzer, so that carbon matrix has little effect on the determination of total mercury. The pipeline length is less than 50 cm with high temperature. It is easy to eliminate the residual mercury rapidly on the pipe and reduce memory effects. The method has a relative standard deviation (RSD) of less than 8.0% and the minimum detection limit of 0.014 μg/g, which is consistent with the AFS's results.