磷石膏中主要元素的分布特征分析

对新鲜和堆存1~4年磷石膏进行了采样,分析了Ti、Cr等15种元素随时间的变化规律及其产生的主要原因。研究结果表明,F、Mg、Na、K等元素含量较高,Cd、I、Co等的含量较低。F、K、Fe、Zn、Mg、Cr等元素的流失率很高,范围为69.2%~100%,其在磷石膏中主要以可溶性离子存在;随堆存时间的增长,Ti、Ni元素的含量有所增加,分析认为其在磷石膏中分别以难溶于水的H2TiO3和Mi2Ni(SO4)2·6H2O(Mi为碱金属离子)存在,并且随着可溶性元素的流失,相对含量有所增加;Na、Co、Sr、Pb略微下降,Na生成难溶于水的Na2SiF6,Co在磷石膏中主要以CoSO4·7H2O存在,Sr、Pb在磷石膏中主要以微溶水的SrSO4、PbSO4存在,其流失量较小;Cd和I在磷石膏中的含量极低,几乎均低于检测值。

Analysis of the Distribution Characteristics of Major Elements in Phosphogypsum

The distribution and variation causes of the 15 elements'' contents were studied in fresh and 1~4 years'' stored phosphogypsum. The results showed that the contents of F, Mg, Na and K are higher while those of Cd, I and Co are lower. The loss rates of the seven elements, including F, K, Fe, Zn, Mg, etc., whose existing forms are water-soluble ions in the phosphogypsum, are relatively high and range from 69.2% to 100%. The relative contents of Ti and Ni tend to increase with increasing stored time and the loss of water-soluble elements, mainly because the existing states of Ti and Ni in the phosphogypsum are H₂TiO₃ and Mi₂Ni(SO₄)₂·6H₂O, the insoluble substances. Besides, the contents of Na, Co, Sr and Pb in 4 years'' stored phosphogypsum are slightly lower than in fresh phosphogypsum, and their existing forms are Na₂SiF₆, CoSO₄·7H₂O, SrSO₄ and PbSO₄, respectively. The contents of Cd and I in phosphogypsum are extremely low, almost of which are below the detection limit.