电感耦合等离子体原子发射光谱法测定多金属矿中二氧化硅

多金属矿具有重要的研究和开采价值,测定其中的二氧化硅含量,对于综合判断多金属矿石的化学组成、矿物组成具有重要意义,现有测定方法不能满足快速准确分析多金属矿石中二氧化硅的需求。实验称取0.100 0 g样品于银坩埚中,加1.0 g氢氧化钠,于马弗炉中从室温逐步升温至640 ℃熔融,在塑料烧杯中经水浸取后,将浸取液倒入热的盐酸(1+1)中,并不断搅拌,再将溶液加热至沸,冷却后定容于250 mL容量瓶中,最终控制溶液为5%盐酸酸度。选择Si 251.611 nm作为分析线,建立了使用电感耦合等离子体原子发射光谱法(ICP-AES)测定多金属矿石中二氧化硅的方法。结果表明,二氧化硅的质量浓度在1.00～50.00 μg/mL范围内与其发射强度呈线性关系,线性相关系数为0.999 8;方法检出限为0.01%(质量分数,下同),定量限为0.04%。按照实验方法测定多金属矿石样品中二氧化硅,结果的相对标准偏差(RSD,n=6)小于3%;测定多金属矿有证标准物质中二氧化硅,其相对误差绝对值小于3.1%,测定值与推荐值相吻合。

Determination of silicon dioxide in polymetallic ore by inductively coupled plasma atomic emission spectrometry

Polymetallic ore has important research and mining value. The determination of silicon dioxide content is of great significance for the comprehensive analysis of chemical composition and mineral composition of polymetallic ore. The existing measurement methods cannot meet the requirements of rapid and accurate analysis of silicon dioxide in polymetallic ore. In experiments, 0.100 0 g of sample was weighed and transferred into a silver crucible. After adding 1.0 g of sodium hydroxide, and mixture was fused in muffle furnace where the temperature was gradually increased from room temperature to 640 ℃. The melt was extracted with water in a plastic beaker. The leaching solution was poured into hot hydrochloric acid solution (1+1), and constantly stirred. Then the solution was heated to boiling. After cooling, the solution was diluted to 250 mL in a volumetric flask, and the acidity of final solution was controlled at 5% hydrochloric acid. Si 251.611 nm was selected as the analytical line. Thereafter a method for the determination of silicon dioxide content in polymetallic ore by inductively coupled plasma atomic emission spectrometry (ICP-AES) was established. The results showed that the mass concentration of silicon dioxide had a linear relationship with the corresponding emission intensity in the range of 1.00-50.00 μg/mL, and the linear correlation coefficient was 0.999 8. The limit of detection was 0.01% (mass fraction, similarly hereinafter). The limit of quantification was 0.04%. The content of silicon dioxide in polymetallic ore sample was determined according to the experimental method, and the relative standard deviation (RSD, n=6) of the determination results was less than 3%. The proposed method was applied for the determination of silicon dioxide in certified reference materials of polymetallic ore. The absolute value of relative error was less than 3.1%. The found results were consistent with the recommended values.