Silica powder coated with passivating layer on surface and passivation processing method of silica powder

Abstract

The invention relates to the photovoltaic field, providing silica powder coated with a passivating layer on the surface, in particular providing silica powder with the passivating layer on the surface in the field of production and processing of silicon chips. The invention also relates to a passivation processing method of silica powder. The invention provides silica powder coated with a passivation layer on the surface, wherein the surface of the silica powder is coated with a layer of compact passivating layer which is silicon dioxide. The invention also provides a passivation processing method of silica powder coated with a passivation layer, comprising the following steps: adding strong oxidizing agent into the silica powder; and leading the strong oxidizing agent to react with the surface of the silica powder to generate a compact silicon dioxide layer. In the invention, strong oxidizing agent is added to carry out passivation processing on the silica powder to obtain silica powder coated with a passivation layer on the surface, thus meeting the condition that silica powder can be stored in water or air for a long time, while the oxidation ratio of silica powder is maintained at a lower range, thus greatly improving storage limits of the silica powder and simultaneously improving utilization ratio of silica powder.

Description

technical field [0001] The invention relates to a silicon powder covered with a passivation layer on the surface in the field of photovoltaics, especially a silicon powder covered with a passivation layer on the surface in the field of production and processing of silicon wafers. The invention also relates to the passivation layer of the silicon powder. treatment method. Background technique [0002] The surface atoms of clean silicon are highly unstable, so oxides are easily formed on the surface of silicon in air, water and aqueous solutions. During the preparation of solar-grade high-purity silicon and the cutting of silicon ingots, a large amount of crystalline silicon exists in the form of silicon powder. In purification technology, silicon powder crushed from metallurgical grade silicon blocks is generally used as raw material; in the process of band sawing and multi-wire cutting of crystalline silicon, a large amount of high-purity silicon powder enters water or cutt...

AI Technical Summary

Problems solved by technology

These silica powders have a large specific surface area, a large number of dangling bonds, and long-term contact with oxidizing media such as air and water, resulting in serious oxidation of silica powder.