Method for preparing fumed silica and anhydrous hydrofluoric acid by utilizing phosphatic fertilizer by-product fluosilicate as raw material

Abstract

The invention discloses a method for preparing fumed silica and anhydrous hydrofluoric acid by utilizing phosphatic fertilizer by-product fluosilicate as raw material. The method comprises the steps as follows: performing pyrolysis on the phosphatic fertilizer by-product fluosilicate at the temperature of 200-400 DEG C to obtain silicon tetrafluoride, utilizing a filter to remove dust containing in the silicon tetrafluoride, washing the silicon tetrafluoride by 93-98 percent of concentrated sulfuric acid to remove the moisture and impurities, mixing the silicon tetrafluoride, air with hydrogen in a hydrolysis reactor via the volume ratio of 1:2:(0.05-0.3) and performing high-temperature hydrolysis reaction, and then performing aggregation, separation, dust removal, condensation and distillation to obtain the fumed silica and the anhydrous hydrofluoric acid respectively. The method has the advantages that the technical process is simple, the raw material is easy to get, the utilization rate of the raw material is high, energy conservation and environmental protection are realized, the corrosion to the equipment is less, the production cost is reduced, and the produced white carbon black is high in purity.

Description

technical field [0001] The invention relates to a method for preparing gas-phase white carbon black and anhydrous hydrofluoric acid, in particular to a method for preparing gas-phase white carbon black and anhydrous hydrofluoric acid by using fluorosilicate, a by-product of phosphate fertilizer, as a raw material. Background technique [0002] Fumed white carbon black is white amorphous flocculent translucent solid colloidal extremely fine particles, and its chemical formula can be written as SiO 2 ·nH 2 O, the appearance is fluffy white powder, non-toxic and tasteless, insoluble in water and acid, chemically stable, high temperature resistant, non-combustible, and has high electrical insulation. Fumed silica has been widely used in many industrial fields such as rubber, paint, medicine, papermaking, etc. due to its superior stability, reinforcement, thickening and thixotropy, and has provided new opportunities for the development of many industrial fields. Material and te...

AI Technical Summary

Problems solved by technology

[0005] The name of the Chinese invention patent is a method for preparing hydrogen fluoride and co-producing white carbon black with silicon tetrafluoride (application number: CN201110192918.7), which discloses a method for preparing hydrogen fluoride and co-producing white carbon black with silicon tetrafluoride, and the by-product of phosphate fertilizer After the crude silicon tetrafluoride gas is dedusted and dehumidified, it undergoes a hydrolysis reaction with the reaction amount of water vapor under the condition of 200-800 ° C, and the obtained product is separated from the gas and solid to obtain hydrogen fluoride and white carbon black. The raw materials are easy to obtain, The price is low, and the raw material utilization rate is high, but the white carbon black particle that this method produces is big, does not possess fumed white carbon black, is white amorphous flocculant translucent solid colloidal nanoparticle (particle diameter is less than 100nm) under normal state. features

Images