用含氟污泥和含氟硫酸生产氟化钙的工艺研究

Research on the Technology of Producing CaF_2 with Fluoride Sludge and Fluoride Sulfuric Acid

含氟污泥,指的是用石灰化学沉淀法处理含氟废水后产生的底泥。含氟硫酸,指的是分解钽、铌矿石后排出的废液。研究了以含氟污泥和含氟硫酸为原料生产氟化钙的新工艺。该工艺由常压蒸馏、一次酸化、沉淀转化、二次酸化和烘干煅烧五个工序组成。工艺流程简单,生产易于控制。工艺过程中没有废水、废气和废渣对环境的二次污染。产品氟化钙的收率可达97%以上,氟化钙的质量分数在91%以上,二氧化硅的质量分数在1.0%以下。产品的质量完全可以满足生产氢氟酸等以萤石作原料的企业的要求。该工艺不但减轻了生产钽、铌企业处理含氟废水的负荷,而且有效的解决了含氟污泥露天堆放的占地问题以及对地下水源造成的二次污染问题,同时还使氟资源得到了充分的循环利用。

Fluoride sludge generated in the process of treating F -containing wastewater by lime chemical sediment , and much waste liquid generated in the other process of decomposing tantalum and niobium ore , which was fluoride sulfuric acid.A new technology that producing CaF 2 with fluoride sludge and fluoride sulfuric acid was studied , which included five processes of the atmospheric distillation , the first acidification , precipitation transformation , secondary acidification and drying calcination.There was no secondary pollution to environment that caused by waste water , waste gas and waste residue.What＇s more, the process was simple and easy to control , and the quality of CaF 2 had completely met the requirement of enterprises that producing hydrofluoric acid with fluorite.The yield of CaF 2 and the mass fraction was greater than 97%and 91%respectively , meanwhile , the mass fraction of silicon dioxide was lesser than 1.0%.Not only much load of treating F -containing wastewater tremendously reduced , but also solved the fluoride sludge covering problem and the secondary pollution for the underground water which caused by fluoride sludge deposited in the open air , and fluorine got fully recycling of resources.