Comprehensive utilization of silicon powder

Published: 07th March 2012
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Because of the great attention of environmental protection, many countries require that electric furnace flue of silicon and industrial silicon ferroalloy should be released after removing dust. In this way, the silica fume increased, and it encourages people to find ways for silica fume application. Development and utilization work of silicon powder resources began in the 1950s. There are existing engineering applications in the late sixties and early seventies. In Northern Europe, Western Europe, North America, Japan, Australia, South Africa and the Soviet Union, silica powders are widely used in cement, concrete, fire-resistant, injection materials, rubber and chemical industry. It has developed a number of excellent new products.
The powder is produced in an electric furnace containing silica fume in more than 75% of silicon ferroalloys and industrial silicon, resulting in a large number of highly volatile SiO2 and Si gas and air is rapid oxidation and condensation from, and generally produce 10-20 % of silica fume. Norway, Iceland, Canada and other countries of the ferroalloy plant to recover part of the silica fume are used as cement raw materials. Its application method are as follows: for the cement material ingredient in the production of the raw material of Portland blended with 18 to 25% silica fume, cement kilns can increase the yield and quality of cement kiln capacity increased by 10-20%; cement health after 28 days, from 47Pa to improve to 54-56Mpa. Cement by silica fume, special admixtures plus cement clinker from the preparation. Caused by the high density concrete made using it, enhanced 2-3 times strength than ordinary concrete, good corrosion resistance, insulation, abrasion resistance, impermeability, frost resistance and chloride ion barrier properties. Denmark has been the cement used for corrosion, wear food factories and heavy machinery ground and requirements of insulation and blocking the chloride ion corrosion layer, hydraulic concrete works, you can also replace part of the metal nickel powder products. Denmark is the Institute for steel corrosion protection coatings with cement; Atomic energy research institute is working on it for the protection of radioactive waste isolation materials.
Application of silica fume in construction, building materials operations is the main use way. Since 1983, in North America, Europe, Japan has a lot of silica fume concrete. Each year there are about 40,000 tons of silica fume used in concrete, the equivalent of 500,000 tons of cement mixed with silica fume. Canada 1981-1985 using a total of 1 million m3 of silica fume concrete.
Silica fume can be applied to the water glass of Health. With silica fume in the case of simplify the process to produce the modulus is greater than 4 water glass. Above the water glass modulus 4 is neutral, can be used in high temperature boron powder coating, steel and other aspects. Shanghai has been the use of this water glass. Fill cuisine of the silica fume used as organic compounds, silicon containing silica and similar Sio2 content, both similar and other physical properties, and thus silica fume can be used as the filler material of rubber, resins and other organic compounds. For varieties of agricultural fertilizer and soil improvement, silicon and potassium hydroxide or potassium carbonate mixed heating can be made to slow agricultural fertilizer potassium silicate, it is less volatile loss, protect the soil to promote crop root development, inhibition of pests and diseases. Silica fume can also be used as a fertilizer anti-caking agent, Norway, France and Italy using this method to prevent the fertilizer particle agglomeration effect is very good.
In short, the silica fume once was considered as a dust and smoke serious polluting the environment. Now the use by the national research has proven that it is a valuable commodity. With the deepening and development of people's understanding and practice, new ways of use will be found and it will continuously improve its use value.Source:http://www.mhcmp.com


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