Method of producing nanometallic silicon powder from silicon sludge

Abstract

The invention discloses a method of producing nanometallic silicon powder from silicon sludge. According to the method, the raw material silicon sludge is subjected to pre-dewatering or airing treatment and then is crushed and dried, and finally the nanometallic silicon powder is prepared after bagging. The grain fineness of the obtained nanometallic silicon powder accounts for 80% or above withinthe range of 5.5-10.5 micrometers; the water content is 1% or less; the content of impurities including SiO<2> is 1-7%; and the content of elemental silicon is 92-98%. Through the method, the technological production process is thoroughly changed, low energy consumption and low pollution are achieved through a pure physical process, the potential value of the industrial byproduct silicon sludge is utilized practically and efficiently, the silicon sludge is deeply processed into the nanometallic silicon powder, energy conservation, emission reduction and recycling are achieved to the maximum extent, and the method has a certain economical value and social benefit when transformed into industrial production.

Description

technical field [0001] The invention belongs to the technical field of silicon material preparation, and in particular relates to a method for producing nanometer metal silicon powder from silicon mud. Background technique [0002] When diamond cuts silicon rods or silicon ingots, in order to ensure processing accuracy and improve the surface quality of silicon wafers, auxiliary cutting fluid is needed to lubricate and rinse the cutting surface to form silicon mud. Silicon mud includes silicon powder and diamond abrasive shedding residue produced by diamond wire in the process of cutting silicon rods or silicon ingots. The average size of the silicon powder is 5.5-12 μm. The liquid components in silicon mud include water, diethylene glycol or ethylene Cutting fluid emulsifiers such as glycol or polyethylene glycol, and surfactants, etc. Due to the small size of silicon powder in "silicon mud" and containing moisture and non-silicon impurities, it is difficult to recycle and...

AI Technical Summary

Problems solved by technology

Generally, it is used as a refractory material after drying and dehydration, or as a raw material for iron and steel smelting after simple sintering, resulting in a large amount of silica mud that cannot be effectively recycled and used in polysilicon processing.

Due to the low price of silicon mud and the inability to effectively reuse it in silicon wafer processing, the production cost of polysilicon is limited and energy is wasted

[0003] At present, the application method of the by-product silicon mud in the photovoltaic industry in the market is: use an intermediate frequency furnace to melt and recrystallize into silicon ingots, and this process requires high standards for the raw materials of the silicon mud, that is, the elemental silicon content of the silicon mud after drying is 95%. -98%, which leads to limited selection of silicon mud, and the processing and production of silicon ingots will generate a large amount of dust whether it is in the drying process or in the melting process of entering the melting furnace, which will cause serious dust pollution to the environment. At the same time, the production of this process belongs to An industry with high energy consumption and high pollution, which conflicts with the industrial upgrading, energy conservation and environmental protection advocated by the current government

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