Preparation process of silicon metal powder with high chemical activity and low fine powder rate and special equipment

Abstract

The invention particularly relates to a preparation process of silicon metal powder with high chemical activity and low fine powder rate specific to the photovoltaic industry, and belongs to the field of processing of silicon materials. In the preparation process, a jaw crusher is firstly used for crushing raw materials for the first time till the diameter of the crushed raw materials reaches 2 to 5 centimeters; after the materials is deironization, the materials are conveyed to a cyclone mill and crushed for the second time to prepare semi-finished silicon powder with the particle size of 700 to 50 Mum; after re-deironization, according to the requirement on particle size of a finished product, the semi-finished silicon powder is screened by a vibrating screen of a screening machine into a larger-particle-size powder section, a finished product section and a smaller-particle-size powder section in terms of particle size sections; the powder of the larger-particle-size powder section is re-crushed; and the semi-finished powder of the finished product section and the smaller-particle-size powder section are proportioned to prepare the finished product finally. In the preparation process of the silicon metal powder disclosed by the invention, a revolving type silicon metal crushing technology is adopted, a wind power-mechanical power combined method is utilized to drive the silicon metal to move at a high speed automatically and be crushed mutually into powder, thus the specific surface area of metal silicon powder reaches 0.69 square meters per gram, and the fine powder rate is reduced within 8 percent simultaneously.

Description

technical field [0001] The invention relates to a preparation process of metal silicon powder, in particular to a preparation process and special equipment of metal silicon powder with high chemical activity and low fine powder rate for the solar photovoltaic industry, belonging to the field of silicon material processing. Background technique [0002] For the solar photovoltaic industry, the specific surface area of ​​metal silicon powder is an important indicator of the activity of silicon powder. The specific surface area of ​​powder particles is the surface area occupied by unit mass in ㎡ / g. The larger the specific surface area of ​​silicon powder, the faster the reaction speed, the more perfect the reaction, the higher the silicon utilization rate, the more ideal fluidized state in the reaction area, and the lower the silicon consumption rate, which shows that its activity is higher. In the prior art, there are many methods for preparing silicon powder from silicon bloc...

AI Technical Summary

Problems solved by technology

The first three kinds of processing equipment prepare metal silicon powder, there is direct friction and extrusion movement between metal and silicon, so it is easy to over-powder and seriously cause the fine powder rate to be too high, generally exceeding 15%, or even 25%, the fine powder rate is too high lead to high production costs

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