铝土矿有效铝含量测定影响因素研究

研究了影响铝土矿中有效铝含量测定的主要影响因素。主要探讨了样品粒度、均匀性对有效铝溶出效果的影响及样品组成对有效铝含量大小的影响。利用电感耦合等离子体原子发射光谱(ICP-AES)法测定铝土矿中有效铝含量、X射线荧光光谱(XRF)法测定铝土矿中总氧化铝含量和其它杂质成分含量,借助X射线衍射光谱(XRD)法对样品进行物相组成分析,确定各主要组成的结构和占比。将样品制备至0.106mm以下,均匀性好,精密度高,有效铝溶出率高。样品物相组成中三水铝石占比高,一水铝石占比低,与氢氧化钠低温条件更易反应,使溶出率高。通过加标回收实验验证方法的加标回收率为99.1%～101%,实验标准偏差为0.14%,相对标准偏差为0.003%,可对铝土矿有效铝的监控提供技术支撑。

Study on Influencing Factors of determination of effective aluminum content in bauxite

The main factors affecting the determination of effective aluminum content in bauxite were studied. The effect of sample size and uniformity on the dissolution of available aluminum and the effect of sample composition on the content of available aluminum were discussed. The content of effective aluminum in bauxite was determined by inductively coupled plasma atomic emission spectrometry(ICP-AES). The content of total alumina and other impurities in bauxite was determined by X-ray fluorescence spectrometry (XRF). The phase composition of samples was analyzed by X-ray diffraction spectrometry (XRD). The structure and proportion of main components were determined, so as to dissolve and measure the effective aluminum. The sample uniformity is good and the effective aluminum dissolution rate is high because of the sample size less than 0.106mm. And the precision of the testing is high. The proportion of gibbsite is high and monohydrate is low for the saomples. So It is easier to react with sodium hydroxide at low temperature, resulting in high dissolution rate. The experimental accuracy is from 99.10 to 100.80% and the experimental standard deviation is 0.14% and the relative standard deviation is 0.003%. It plays an important guiding role and provides technical support for the monitoring of effective aluminum in bauxite.