Method for cleaning circulation tailings generated in polycrystalline-silicon ingot-casting half-melting technology

Abstract

The invention discloses a method for cleaning circulation tailings generated in the polycrystalline-silicon ingot-casting half-melting technology, and relates to the solar silicon material cleaning technology. The method includes the following steps that a, impurities with which the surfaces of the tailings are covered are cleanly removed with compressed air; b, soaking is carried out with cleaning liquid, wherein hydrofluoric acid, hydrogen peroxide and pure water are prepared into the cleaning liquid; c, after impurities in tailing gaps are cleaned and removed, the surface covered substances are washed down with pure water; d, cleaning is carried out with acid mixed liquid, wherein nitric acid and electronic-grade hydrofluoric acid are prepared into the acid mixed liquid, acid cleaning is carried out, and then rinsing is carried out with pure water; e, ultrasonic cleaning is carried out, wherein dirt in the surfaces, dirt in silicon material gaps and acid liquid residues are cleaned and removed, and clean tailings are obtained. The method has the advantages that according to preparing of different kinds of acid liquid and multiple-time cleaning, waste cutting liquid and impurities generated in the on-line cutting process in the circulation tailing gaps in the ingot-casting half-melting technology are thoroughly removed, the quality level of the half-melting tailings is improved, the ingot-casting production cost is reduced, the furnace putting quantities of the circulation materials are increased accordingly, and the aims of reducing the cost and improving the efficiency are achieved.

Description

technical field [0001] The invention relates to the technical field of solar polysilicon chip manufacturing, in particular to the polysilicon cycle material washing technology. Background technique [0002] With the mature development of polysilicon ingot semi-melting process and a large number of imports into production, there are a large number of unmelted voids at the bottom of the tailing (bottom material) produced by this process. liquid, silicon carbide powder, and copper-iron metal impurities. Pickling in the market is generally done by knocking or raising the drying temperature. Incomplete treatment of tailing impurities after pickling treatment will have a great impact on the quality of the ingot. In severe cases, it can only be downgraded. Use for purification. [0003] Through a large number of tests, the present invention has explored the method of soaking with hydrofluoric acid and hydrogen peroxide cleaning solution (this step is the focus of improving the qua...

AI Technical Summary

Problems solved by technology

[0002] With the mature development of polysilicon ingot semi-melting process and a large number of imports into production, there are a large number of unmelted voids at the bottom of the tailing (bottom material) produced by this process. liquid, silicon carbide powder, and copper-iron metal impurities. Pickling in the market is generally done by knocking or raising the drying temperature. Incomplete treatment of tailing impurities after pickling treatment will have a great impact on the quality of the ingot. In severe cases, it can only be downgraded. Purification and use