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Abstract

The present invention relates to a process for recovery of particulate calcium fluoride from a waste solution containing soluble fluoride. More specifically, the invention relates to a process for removal of soluble fluoride from and recovery of fluorspar-grade calcium fluoride from an aqueous waste solution using calcium sulfate to form the calcium fluoride. One aspect of the present invention is a process for removing soluble fluoride from a solution containing such soluble fluoride, the process including: (A) mixing the waste solution with an aqueous slurry containing seed calcium fluoride particles to form a first aqueous composition; (B) mixing the first aqueous composition with a calcium containing reagent to form a second aqueous composition; (C) advancing the second aqueous composition through a tubular reactor for an effective period of time and at a velocity sufficient to permit the soluble fluoride and the calcium containing reagent to react and attach to the seed particles of calcium fluoride, the seed particles of calcium fluoride thereby increasing in size to become enhanced particles; and (D) removing from the second aqueous composition a portion of the enhanced particles of calcium fluoride.

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First Claim