高镁磷尾矿制备二水硫酸钙晶须的研究探讨

Study on Preparation of Calcium Sulfate Dichloride Whisker from High Magnesium Phosphate Tailings

以高镁磷尾矿为原料,采用常压酸化法制备二水硫酸钙晶须,通过单因素条件试验考察了H+浓度、Mg2+浓度、PO43-浓度及Fe3+浓度等因素对晶须长径比的影响,并通过对比试验探究了滴加方法及酸解液陈化的影响。结果表明,制备硫酸钙晶须的最佳工艺条件为:在反滴且酸解液陈化的前提下,H+浓度为3 mol/L,Mg2+浓度为3.27 mol/L,PO43-为1.112 mol/L,同时尽量除去Fe3+,在此条件下制备而成的硫酸钙晶须长径比达到50以上,且形貌均一。

Calcium sulfate dihydrate whiskers were prepared from high magnesium phosphate tailings by acidizing at atmospheric pressure.The effects of H+concentration,Mg2+concentration,PO43-concentration and Fe3+concentration on the length to diameter ratio of whiskers were investigated by single factor test.The effects of drop addition method and aging of acid hydrolysate were also investigated by comparative experiments.The results showed that the optimum technological conditions for preparing calcium sulfate whiskers were as follows:the concentration of H+,Mg2+and PO43-were 3 mol/L,3.27 mol/L and 1.112 mol/L,respectively,while Fe3+was removed as far as possible under the condition of reverse drop and aging of acid solution.Under these conditions,the length-diameter ratio of calcium sulfate whisker is more than 50,and the morphology is uniform.