| When crude lead containing lead, bismuth, antimony, gold, silver, platinum and palladium is determined by fire assay gravimetric method, the content data of platinum and palladium cannot be obtained at the same time. The sample is wrapped with lead foil and placed in an ash dish. The composite particles of precious metals (containing a small amount of bismuth and lead) are obtained by direct soot blowing at 860 ℃. The composite particles can be dissolved in silver with nitric acid, supplemented with excess hydrochloric acid to dissolve gold, platinum and palladium. The contents of gold, platinum, palladium and main impurity elements (bismuth and lead) in the test solution are measured by inductively coupled plasma atomic emission spectrometry (ICP-AES). The content of silver can be obtained by subtraction. The simultaneous determination of gold, silver, platinum and palladium was realized. The relative standard deviation (RSD) of the determination results of gold, silver, platinum and palladium are less than 2.95%, and the recovery is between 98.0% ~ 99.8%, which meets the requirements of production determination. |
