company name: gansu lixinyuan microsilica co. ltd
contact person: manager sun
email address: [email protected]
address: no. 2599, yanbei road, chengguan district, lanzhou city, gansu province
in industrial silicon and ferrosilicon production with cloth bag dust remover from the furnace smoke received dust dust is generally known as micro silicon powder, its particle size is very fine, the composition is mainly silicon oxide, small density, greater than resistance, strong adhesion, adhesion, not easy settlement. with the increase of industrial silicon and ferrosilicon output, the production of micro-silicon powder is also increasing. it is estimated that the potential resource of micro-silicon powder in china is more than 400,000 t per year, but many domestic manufacturers do not have dust recovery devices, a large number of micro-silicon powder because there is no recycling, flowing everywhere, severe environmental pollution.
the research on the comprehensive development and utilization of micro-silicon powder resources started in the 1950s, and has been applied in engineering by the end of the 1960s. after long-term research and practice at home and abroad, micro-silicon powder has been applied in cement, chemical industry, rubber and other fields, achieving good results and developing a batch of new products with excellent performance.
form of silica powder
when smelting industrial silicon and ferrosilicon in electric furnace, silica in silica is reduced by carbon reducing agent:
formation of silica powder
in fact, the reaction is not in accordance with the above general equation, but step by step reduction, sir into the intermediate product:
silica powder reaction formula
sio2 generates intermediate products sio and sic in the reduction process, and some of the intermediate products sio escape from the furnace in the gaseous state, thus resulting in the loss of silicon. when sio evaporates to select the material surface, in the presence of oxygen, it will be burned to generate fine scattered sio2 and emit white flame:
formation of silica powder
at this time, due to sudden cooling, the temperature gradient changes greatly, and the generated sio2 has no time to crystallize, while the generated amorphous phase sio2, namely silica powder, has extremely small particle size. in the actual production, the silicon volatilization loss is related to the raw material size, feeding mode and operation level. under normal production conditions, 1t industrial silicon is smelted to produce 120 ~ 190kg micro silica powder. in the micro silica powder, besides sio2 micro powder generated by furnace gas oxidation and dismutation-reaction, it also contains fine powder that escapes with furnace gas, such as 10% ~ 20% silica and carbon reducing agent.
the factors that affect the formation of silica powder mainly include the ratio of coke to sio2 in the charge, the resistivity of the charge and the temperature of the charge.