关键词: 含氟底泥, 氟化钙, 二氧化硅, 盐酸

Abstract: A large amount of sediment，which mainly consists of CaF2，Ca（OH）2，and CaCO3，was generated when disposing industrial fluoride wastewater by lime-chemical precipitation method.A new technology to extract CaF2 from sediment by using hydrochloric acid，sodium carbonate，and caustic soda as the raw materials was studied.This technology mainly consisted of five procedures including first acidification，transformation of precipitation，silicon removing by caustic soda， second acidification，and drying and calcining.The process was relatively simple，and the process conditions and the requirement for the equipment material were both easy to meet；and the production was easy to control.During the process， there was no wastewater，waste gas，and waste residue to pollute the environment.The recovery rate of the product，CaF2，can reach above 96%，and the mass fraction of CaF2 was above 90%，while the mass fraction of silica was below 1.2%.It effectively resolved the land occupation issue and environmental issue caused by stacking the sediment in the open，and made the fluorine resource get fully cyclic utilization.

Key words: F-containing sediment, calcium fluoride, silicon dioxide, hydrochloric acid