熔融制样-X射线荧光光谱法测定铝矿中15种组分

铝矿中主、次及微量成分含量对生产工艺及产品质量具有重要影响,传统的检测方法操作过程繁琐,分析周期长,已难以满足检测需求。实验采用熔融法制样,样品经硝酸锂预氧化后,选择质量比为12∶22的Li₂B₄O₇和LiBO₂混合试剂作为熔剂,熔剂与样品比例为10∶1,以NH₄I为脱模剂,在1050℃下熔融10min制备熔片。采用有证标准物质及其与高纯Al₂O₃的人工合成样品为校准样品,对谱线重叠情况进行了考察,并通过变化的理论α系数法校正元素间的吸收增强效应,建立了铝矿中Al₂O₃、SiO₂、Fe₂O₃、CaO、MgO、P₂O₅、Na₂O、K₂O、TiO₂、MnO、Ga₂O₃、ZrO₂、V₂O₅、Cr₂O₃及S等15种组分的X射线荧光光谱法(XRF)。精密度实验表明,各组分测定结果的相对标准偏差(RSD,n=9)在0.18%~12%之间;对标准样品进行正确度考察,测定值与认定值一致。方法可同时满足铝土矿、叶蜡石、莫来石、矾土、高岭土等多种铝矿的测定。

Determination of fifteen components in aluminum ore by X-ray fluorescence spectrometry with fusion sample preparation

The contents of major, minor and micro components in aluminum ores have important influence on the production process and product quality. However, traditional analysis method cannot satisfy the detection requirements due to the tedious operation and long determination period. The sample was prepared by the fusion method. The samples were pre-oxidized by lithium nitrate for sample preparation under the following conditions: Li₂B₄O₇-LiBO₂ mixture [m(Li₂B₄O₇)∶m(LiBO₂)=12∶22] was selected as flux; the ratio between flux and sample was 10∶1; NH₄I was employed as the releasing agent; the sample was fused at 1050℃ for 10min. The certified reference materials and their mixture with high purity aluminum oxide was used as calibrations sample. The spectral overlapping was investigated. The absorption enhancement effect among elements was corrected by variable theoretical α influence coefficient method. The simultaneous determination method of fifteen elements in aluminum ores (including Al₂O₃, SiO₂, Fe₂O₃, CaO, MgO, P₂O₅, Na₂O, K₂O, TiO₂, MnO, Ga₂O₃, ZrO₂, V₂O₅, Cr₂O₃ and S) by X-ray fluorescence spectrometry (XRF) was developed. The precision test showed that relative standard deviations (RSD, n=9) were between 0.18% and 12%. The accuracy test was conducted using standard samples, and the found results were consistent with the certified values. The proposed method could simultaneously meet the determination requirements of various aluminum ores such as bauxite, pyrophyllite, mullite, aluminite and kaolin.