Silica Grinding and Classifying Process

Description：silica powder, inclusive of X- ray amorphous silica and silicate powder products, mainly refers to precipitated silica, fumed silica, silica gel and superfine aerogel, powdered synthetic aluminum silicate and calcium silicate. Silica is a porous material, with the general composition of SiO₂ • nH₂O, where nH₂O is the form of present surface hydroxyl groups. Silica is soluble in caustic alkali and hydrofluoric acid, insoluble in water, solvents and acids (except hydrofluoric acid). In addition, silica has high temperature and flame resistant properties, tasteless, odorless, and good electrical insulation.

Silica powder production process： silica can be divided into precipitated silica and fumed silica according to production methods. Generally, fumed silica production method is half of precipitated silica. These transparent solid colloidal nanoparticles (particle size less than 100nm) are non-toxic and have a large surface area. All fumed nano-silica powder can achieve 99% purity with particle sizes down to 10 - 20nm, but the preparation process is complex and expensive. Precipitated silica preparation has both traditional and special precipitation methods. The former refers to using sulfuric acid, hydrochloric acid, CO₂ and glass as the basic raw materials to produce silica, which is the use of gravity technology, sol - gel method, chemical crystallography, secondary crystallization special methods or micelles microemulsions and monolayers method for production of silica. Precipitated silica is mainly used as a natural rubber and synthetic rubber reinforcing agent, toothpaste friction agent. Fumed silica is mainly used as a reinforcing agent for silicone rubber, coatings and unsaturated resin thickener, ultrafine silica gel and aerogel coatings are mainly used as matting agents, thickeners, plastic film opening agent.

Silica applications：as an environmentally friendly, high performance additive, silica is mainly used for fabricating rubber products (including high temperature vulcanized silicone rubber), textiles, paper, pesticides, and food additives fields. Silica boasts a four-year compound annual growth rate of 13.3% from 2004-2008. In 2009, China has more than 60 silica manufacturing enterprises with a production capacity of about 1 million tons, producing 750,000 tons, leading the global domestic sales. With the development of tire manufacturing, silicon rubber industry, paint industry, new energy and other fields demand growth expected in the future of precipitated silica (silicon dioxide) the average annual demand growth rate of about 10%. By 2015, Asia will become the largest market of highly grinded silica, with the growth in demand much higher than the global average growth of 9%, 15% or higher. China accounts for 40% of the Asian market, becoming the world’s largest single market.

Applicable grinding & classifying processes：FQW / FWL series jet mill, FFW / FFL series air classifier, FJW / FJL series pulverizer.