Micro-silica fume is the dust formed by the Si and SiO gas produced in the process of producing ferrosilicon alloy and metallic silicon in the submerged arc furnace, oxidized with air and rapidly condensed in the flue, also known as silica fume (or condensed silica fume). In recent years, with the strengthening of environmental protection, the output of micro-silica powder has been increasing year by year. If it is directly discharged or dumped, it will cause environmental pollution and waste of resources. Therefore, how to use these huge amounts of micro-silica powder as a resource has become a ferrosilicon smelting Problems that enterprises need to solve urgently.
The main chemical component of micro-silica powder is SiO2, the SiO2 mainly exists in the amorphous phase (or amorphous SiO2), the content is ≥80%, the impurity component is less, the specific surface area is 20-28m2/g, and the particles with the particle size less than 10μm account for Above 80%, it has high chemical activity, easily reacts with alkali, and has the characteristics of light weight, high refractoriness, and strong activity. It is widely used in construction, refractory materials, metallurgy, ceramics, chemical industry and other fields. This paper analyzes the physical and chemical properties of micro-silica fume, a by-product of ferrosilicon smelting, and analyzes the status of comprehensive recycling and utilization of micro-silica fume from the aspects of production, recovery and application, and points out the direction of high-value utilization of micro-silica fume .
In recent years, with the rapid development of the ferrosilicon industry and the country's efforts to improve the environment, the output of ferrosilicon smelting dust has also increased year by year. Microsilica fume is widely used in extensive fields such as special cement, special concrete, refractory materials, metallurgical pellets, etc. However, there is little research on the comprehensive utilization of microsilica fume with high added value.
Silica powder prepared from silica is mostly precipitated silica, with low added value, and it is necessary to further improve the performance of silica. The quality of metal silicon prepared by micro-silica powder is better than that of metallurgical silicon, and it is a high-quality raw material for preparing solar-grade silicon. The adsorption material made of micro-silica powder has a good adsorption effect on heavy metals, CO2 and oil and gas, and is expected to be widely used in environmental treatment. The preparation of silicon aerogel with micro-silica powder as the silicon source has excellent performance, especially non-toxic characteristics and more practical value.
The use of micro-silica powder should focus on the resource utilization, comprehensive and high-value utilization of micro-silica powder, and deep processing of micro-silica powder to improve its physical and chemical properties, making it widely used in electronics, aerospace, medicine, color tires, toothpaste, Rubber and other fields.
