Determination of Chromium in Copper Concentrate by Inductively Coupled Plasma Atomic Emission Spectrometry with High Temperature Alkali Fusion

In order to solve the problem that copper concentrate is difficult to be dissolved by acid dissolution method, a method for the determination of chromium in copper concentrate by inductively coupled plasma atomic emission spectrometry with high temperature alkali fusion was proposed. The sample (0.300 0 g) was taken and placed into an iron crucible, and 3.0 g of potassium hydroxide was covered on the surface of the sample. After the potassium hydroxide was heated to a fluid shape at 300 ℃, the iron crucible was put into a muffle furnace at (700±10)℃ to melt the sample for 15 min, and then 20 mL of hydrochloric acid was added. The mixture was heated at 300 ℃ for 5 min for acidification. After the mixture was cooled to room temperature, its volume was made up to 200 mL with water. An aliquot (5 mL) was taken, and 5 mL of hydrochloric acid was added. The above mixed sdution was made its volume up to 50 mL. After shaking well, the solution obtained was determined according to the operating conditions of the inductively coupled plasma atomic emission spectrometer. It was shown that linear relationship between the mass concentration and the emission intensity of chromium was found within 2.00 mg·L^-1, with detection limit (3s) of 0.92 mg·kg^-1. The method was applied to the analysis of 4 copper concentrate samples. RSDs (n=12) of the determined values were in the range of 3.4%-7.0%, and the determined results of this method were basically consistent with those of other laboratories accredited by CNAS.