铵盐钙盐除杂制备高纯二氧化硅

Producing High Purity Silicon Dioxide Using Ammonium Salt and Calcium Salt to Remove Impurities

以磷肥生产过程中的副产物氟硅酸为原料制备高纯二氧化硅。氟硅酸与氨水反应,得到氟硅酸铵溶液,加入铵盐沉淀钙镁离子,再加入钙盐沉淀铝铁离子,静置后过滤得到净化的氟硅酸铵溶液;将净化液氟硅酸铵与氨水反应生成二氧化硅沉淀,经过滤、热洗、干燥、煅烧,得到高纯二氧化硅。样品SiO_2符合国标要求。实验表明,以氟硅酸制备高纯二氧化硅工艺可行。工艺特点是将低附加值的氟硅酸转化为高附加值的高纯SiO_2,铵盐钙盐除杂适宜,反应步骤少、过程简单、操作条件温和。

High purity SiO2 was prepared with Fluosilicic acid as the raw material, which is the by- product of the production of phosphate fertilizer. Fluosilicic acid reacts with ammonia to obtain Ammonium fluosilicate solution, and add ammonium salt in it to precipitate calcium and magnesium ions, and calcium salt to precipitate iron and aluminum ions, after standing for a while, filter it to obtain national standard. The experiment result shows that it is feasible to use Fluosilicic acid to get high-purity silicon dioxide. The characteristics of this process are as follows, first it can convert low value-added fluorine acid to high value-added high-purity SiO2, then it is appropriate to remove impurities by ammonium salt and calcium salt; at last, there are just few steps, simole orocess and mild reaction condition.