Determination of Gold in Crude Lead by ICP-AES after Separation with Low Temperature Ethanol

A method for determination of gold in crude lead by ICP-AES after separation with low temperature ethanol was established. Crude lead sample (2.0-10.0 g) was taken and dissolved with 33% (volume fraction) nitric acid solution, and then completely dissolved with hydrochloric acid. 1-3 mL of liquid bromine (chloroauric acid protector) was added, and the acid in the solution was driven out by boiling slightly, and the volume of the solution was concentrated to about 20 mL. Liquid bromine (2 mL) and water (50 mL) were added to drive out the acid repeatedly, thus to reduce the acidity of the system. Ethanol (60 mL) was added to the above system, and the solution was placed at 0℃ for 2 h and filtered. The precipitation was discarded, liquid bromine (1-3 mL) was added into the filtrate, and the solution was heated to remove ethanol until the volume reached about 10 mL and then diluted to 10-50 mL with 5% (volume fraction) hydrochloric acid solution for ICP-AES analysis. The results showed that linear relationship between mass concentration of gold and its respective spectral intensity was kept in the range of 0.5-8.0 mg·L^-1, with detection limit (3.143s) of 0.026 g·t^-1. The spiked recovery test was made on pure lead, giving values of recovery more than 96.0%. The prescribed method was applied to the analysis of actual sample and compared with YS/T 248.6-2007, the determined value was basically consistent, and the standard deviation (0.085 g·g^-1) was lower than the repeatability limit (0.5 g·t^-1) calculated by the interpolation method in YS/T 248.6-2007.