碱熔融-电感耦合等离子体原子发射光谱法测定铬矿石中铬铝铁镁硅

铬矿石样品经碱熔融和盐酸浸取后,选用SeaSpray雾化器和旋流雾室,选定了待测元素的分析线,以信号的稳定性为原则,优化了样品提升量、载气流量、冷却气流量和入射功率,实现了电感耦合等离子体原子发射光谱法对铬矿石中铬、铝、铁、镁和硅等主量成分的测定。研究了基体效应,认为钠浓度为3.1~4.0 mg/mL、锆浓度为20μg/mL时,它们分别对各待测元素的测定没有影响;在钠的浓度为3.5 mg/mL时,其它各共存元素间的相互影响可以忽略。考察了酸度效应,发现酸的体积分数为7%~11%时,酸度对各待测元素的影响可以不予考虑。该方法用于4种标准物质的分析,各待测元素的测定值与认定值相吻合,RSD(n=5)为0.2%~0.9%。

Determination of chromium, aluminum, iron, magnesium and silicon in chromium ore by alkali fusion-inductively coupled plasma atomic emission spectrometry

Chromium ore samples were fused by alkali and then leached out by hydrochloric acid. After the analytical lines of the elements were selected, the conditions of sample uptake, carrier gas flow, cooling gas flow and RF power were optimized with the system of SeaSpray nebulizer and cyclone spray chamber, based on the principle of best signal stability. The determination of chromium, aluminum, iron, magnesium and silicon in chromium ores was fulfilled. The matrix effect was discussed: When the concentrations of sodium was 3.1-4.0 mg/mL and zirconium was 20 μg/mL, they did not interfere with the determination of testing elements; When the concentration of sodium was 3.5 (mg/mL,) the interference among the coexisting elements could be ignored. The acidity effect was also investigated. When the volume fraction of acid was about 7 %-11 %, the effect of acidity on each testing element could be ignored. This method has been applied to the determination of four certified reference materials. The found values were in good agreement with the certified values. The relative standard deviation (RSD) was 0.2 %-0.9 % (n=5).