Method for preparing white carbon black from silicon slags containing fluorine

Abstract

The invention discloses a method for preparing white carbon black from silicon slag containing fluorine. The method comprises the steps of: adding silicon slag containing fluoride and measured alkaline solution according to the proportion into a reaction kettle provided with a stirrer and a heating device; heating the mixture to 40-80 DEG C under fully stirring condition for maintaining for 20-50 min, so that the fluosilicic acid in the silicon slag containing fluoride is reacted completely to prepare a mixed solution of silicon dioxide and fluoride salt; heating or cooling the prepared liquid-solid mixture of silicon dioxide and fluoride salt to 50 DEG C or less, then filtering or centrifuging the mixture for liquid-solid separation so as to prepare a wet cake of silica and a filtrate of fluoride salt; backwashing the prepared wet cake of silica for 4-6 times, merging the first washing solution with fluoride salt to prepare a fluoride salt solution for other uses, and putting the second to the sixth washing solution into the first to the fifth washing solution tank respectively for the next first to fifth washing; drying the wet filter cake of silica to obtain white carbon black products. The method has the advantages of simplicity in processing, less equipment, simplicity and convenience in operation, and low production cost, and is convenient to realize industrial production.

Description

technical field [0001] The invention belongs to the field of chemical production, and in particular relates to a method for preparing white carbon black from fluorine-containing silicon slag. [0002] Background technique [0003] A large amount of fluorosilicic acid is by-produced in the production process of phosphate fertilizer industry. When anhydrous hydrogen fluoride is produced from fluorosilicic acid, most of the fluorine is recovered, but a large amount of fluorine-containing silicon slag is produced by-product. Among them, fluorine (including free fluorine and lattice fluorine) is represented by fluorosilicic acid (H 2 SiF 6 ) in the form of silicon dioxide (SiO 2 ) exists in the form of This kind of silica has poor activity and contains fluorine, so it cannot be directly used as a filler in rubber or other fields, and stacking will cause environmental pollution due to fluorine content. Therefore, how to make good use of silicon and fluorine resources in fluor...

AI Technical Summary

Problems solved by technology

The dissolution process of the latter fluorine-containing silica gel consumes more heat and higher energy consumption; the dissolution and precipitation reaction process involves ammonia gas, and due to the volatility of ammonia, the loss of ammonia in actual production is relatively large;