摘要：铝土矿具有较强的化学稳定性，常含有少量刚玉，属于比较难处理的样品。常用的四酸溶解法对不含刚玉的铝土矿能取得较好的效果，但对高铝及含刚玉的样品分解不完全且无法同时测定硅。本文对含刚玉的铝土矿样品在镍坩埚中用氢氧化钠-过氧化钠熔融，盐酸酸化后用电感耦合等离子体发射光谱法同时测定硅铝铁钛四种元素。对氢氧化钠-过氧化钠的熔样效果、过氧化钠用量、熔样温度、共存离子的影响及基体干扰进行了试验，结果表明，加入3.0 g氢氧化钠和1.0 g过氧化钠在650~700℃保温10 min，能较好地熔解含少量刚玉的铝土矿样品。利用铝土矿标准物质制备标准溶液，可消除镍坩埚和熔融试剂产生的镍盐和钠盐基体对硅铝铁钛测定的干扰。方法检出限为0.0025%～0.063%，精密度小于4%。铝土矿国家标准物质的测定值与标准值相符，实际样品的测定值与其他分析方法的测定值相吻合。本方法样品分解完全，消解时间短，分析步骤简单，适用于高铝及含少量刚玉的铝土矿样品分析。

Determination of Si, Al, Fe and Ti in Bauxite by Inductively Coupled Plasma-Atomic Emission Spectrometry

ABSTRACT Bauxite has strong chemical stability, which often contains a small amount of corundum. Therefore, samples are classified to refractory samples by the method of inductive coupled plasma-optical emission spectrometry. The routine 4 acids digestion system works well for non-corundum bearing bauxite, but cannot completely digest the high Al and corundum bearing bauxite and simultaneously determine Si. Four elements of Si, Al, Fe and Ti in bauxite were simultaneously quantified by Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES) after the samples were digested in a Nickel Crucible with NaOH-Na₂O₂ and acid treated. The melting effect, dosage of Na₂O₂, temperature, elementary spectral lines, coexisting ions, matrix interference and elimination of melting samples are discussed in this paper. The results show that corundum bearing bauxite samples are completely melted with 3.0 g NaOH and 1.0 g Na₂O₂ at 650-700℃ for 10 minutes. The standard solution prepared by national bauxite standard material is good to eliminate the matrix interferences for Si, Al, Fe and Ti measurements. The detection limits are 0.0025%-0.063%, and the precisions (RSD, n=11) are 0.15%-3.05%. The measured values of national standard materials were consistent with the certified values, and the measured values of actual samples were consistent with the values by the other methods. This method has the advantages of completely decomposing the sample, having a short digesting time, is simple for analysis procedure, rapid, accurate, has a wide range for determination content and is especially suitable for high Al or corundum bearing bauxite samples.