Determination of gold in ore by ethyl acetate extraction injection-inductively coupled plasma atomic emission spectrometry

Abstract

In order to enhance the analysis efficiency and reduce the analysis cost, and ensure the health of analyst, the selection of one determination method for gold in ore with short analysis time, low reagent toxicity and easy operation is very important. The sample was dissolved with aqua regia followed by quantitative extraction in separating funnel with cheap ethyl acetate which had low toxicity. The extract liquor was directly injected into inductively coupled plasma atomic emission spectrometer (ICP-AES) equipped with organic injection system. Au I 242.795 nm was selected as the analytical line for the determination of gold in ore. Consequently the determination of gold in ore by inductively coupled plasma atomic emission spectrometry (ICP-AES) was established. The interference of matrix and coexisting elements was eliminated by extraction separation method. The optimum experimental conditions were obtained by the conditional tests of extraction acidity, extracting agent, extraction method, working conditions of instrument and analytical lines. The mass concentration of gold in range of 0.10-16.00 mg/L showed linearity to the corresponding emission intensity. The linear correlation coefficient of calibration curve was 0.999 8. The detection limit of gold was 0.02 mg/L. The content of gold in five certified reference materials of ore was determined according to the experimental method. The relative standard deviations (RSD, n=10) of results were less than 3%. The found results were consistent with the certified values. The proposed method could be applied for the ore detection with gold content in range of 0.25-38.0 g/t. The detection time for single sample was about 4 h. The proposed method could be used for batch inspection.