Determination of Gold by Inductively Coupled Plasma Atomic Emission Spectrometry in Cyaniding Deplating Solution Treated by Alkaline Chlorination and Tellurium Co-Precipitation Method

The alkaline chlorination method was used to oxidize and decompose cyanide, and the tellurium co-precipitation method was used for the separation and enrichment of gold in the cyanide-breaking solution. The method of determination of gold in cyaniding deplating solution by inductively coupled plasma atomic emission spectrometry (ICP-AES) has been established. Under alkaline conditions, sodium hypochlorite was used to oxidize and decompose the cyanide in the deplating solution and convert it into carbon dioxide and nitrogen: sodium sulfite solution was used to neutralize the residual chlorine in the cyanide-breaking solution and eliminate the effect of oxides on the cyanide test package. The cyanide-breaking effect of deplating solution can be easily and quickly judged. In the acid medium of 3.6 mol/L hydrochloric acid, the 12.5 mL tellurium solution of 2.5 g/L and 11 mL stannous chloride solution of 1mol/L could quantitatively precipitate 5~500 μg Au, and 50 times excess ion/Au(w/w) interfering ions does not interfere determination. The mass concentration of gold was linear with its emission intensity in the range of 0.05~25.00 mg/L. The calibration equation was y=46.487x+0.343, the correlation coefficient (r) was greater than 0.999 9, and the detection limit was 0.004 4 mg/L. The accuracy of the actual sample was investigated, the relative standard deviation (RSD, n=7) was less than 1.0%, and the recoveries were 96.9%~103.1%. The measurement result of experiment method is in good agreement with the comparison of the fire assay method.