A kind of utilization method of industrial by-product fluosilicic acid

Abstract

The invention discloses a utilization method of industrial by-product fluosilicic acid, i.e. a method for preparation of calcium fluoride and co-production of white carbon black or solica sol with the phosphorus fertilizer industry and fluorine chemical industry by-product fluosilicic acid as the raw material. The method includes: reacting calcium carbonate with fluosilicic acid to obtain calcium fluoride precipitate and a silicic acid solution, conducting filtering, washing and drying to obtain a calcium fluoride product with CaF2% greater than or equal to 97% and SiO2% of smaller than or equal to 1.4%, and concentrating the filtrate by membrane filtration to obtain a high concentration silica sol product, or conducting spray granulation drying to obtain a nanoscale white carbon black product. According to the invention, the calcium fluoride product has good quality, the process is simpler, reduces energy consumption, improves the economical efficiency, also has no adverse effect on the environment, and can achieve co-production of a variety of SiO2 products to meet the needs of different markets. And the obtained white carbon black product has fineness reaching the nanoscale, thus being able to satisfy higher use requirements of users.

Description

Technical field [0001] The invention relates to the utilization of the by-product fluorosilicic acid in the inorganic chemical industry, in particular to a method for preparing calcium fluoride and co-producing white carbon black or silica sol by using the fluorosilicic acid by-product in the phosphate fertilizer industry and the fluorochemical industry as raw materials. Background technique [0002] In both the phosphate fertilizer industry and the hydrogen fluoride industrial production process, a large amount of fluorine and silicon compounds are produced, and these by-products are mainly SiF 4 , HF gas escapes in the form of, in order to ensure that the environment is not polluted, usually water is used to absorb the fluorosilication of these gases and make it a fluorosilicic acid solution. In 2012, my country's phosphate fertilizer industry was converted to 100% content P 2 O 5 The output is 19.559Mt, according to the production of 1 ton P 2 O 5 Calculating that it can produc...

AI Technical Summary

Problems solved by technology

[0010] But there are following problems in these routes: at first, calcium hydroxide raw material is obtained by calcining calcium carbonate in lime kiln, and the decomposition rate of calcium carbonate is generally 94~96%, promptly contains ~88% CaO, ~9% CaCO in quicklime 3 , when reacting with ammonium fluoride, it needs to be heated to a temperature exceeding 90°C, and the reaction time exceeds 2 hours to complete the reaction. Secondly, the recycling of ammonia adopts the method of distillation, which is the same as the process of making soda ash by the ammonia-soda method. Usually, the ammonia-soda method In the ammonia distillation process, the unit product consumes 1641kg of steam with an enthalpy of 2.7MJ / kg; at the same time, due to leakage and waste liquid discharge, the ammonia consumption per unit product is 3kg, which will have an impact on the environment. Therefore, this technical route has high energy consumption , poor economic benefits, problems affecting the environment