A method for preparing white carbon black from fluorine-containing silicon slag

Abstract

The invention discloses a method for preparing white carbon black from fluorine-containing silicon slag. Heating the mixed material to 40~80℃ under certain conditions, maintaining the reaction for 20~50 minutes, so that the fluorosilicic acid in the fluorine-containing silicon slag reacts completely, and a mixed solution of silicon dioxide and fluoride salt is obtained; the obtained silicon dioxide and fluoride salt liquid-solid mixture while hot or cooled to ≤? 50°C, send to filter or centrifuge for liquid-solid separation to obtain silica wet cake and fluoride salt filtrate; carry out countercurrent washing on the obtained silica wet cake for 4 to 6 times, and combine the washing liquid and fluoride salt filtrate The fluoride salt solution is used for other purposes, and the second to sixth times of washing liquid are respectively entered into the first to fifth washing liquid storage tanks for the first to fifth washing of the next time; the silicon dioxide wet filter cake is dried to obtain Silica products. The invention has the advantages of simple technological process, less equipment, simple and convenient operation, low production cost and easy realization of industrialized 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. Background technique [0002] 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 fluorine-contai...

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; comprehensively higher energy consumption and higher ammonia consumption, the production cost of this method is higher; during the washing process, the impurities in the silica wet filter cake are not easy to wash clean, and the quality of the silica product obtained after drying is unstable