A kind of preparation method of low-iron ultra-white fused silica ceramic crucible

Abstract

The invention discloses a method for preparing a low-iron ultra-white fused quartz ceramic crucible. By directly grinding quartz sand with a larger diameter, a high-moisture grinding slurry with a moisture content of 19-21% and a median particle size of 9-11um is obtained, replacing the original There is direct addition of fine powder in quartz sand, which can increase the proportion and amount of coarse sand in direct addition of quartz sand and improve the fluidity of the slurry; the small particle size grinding slurry + large span particle size fused quartz sand is used as the crucible body The basic raw material for molding avoids the main source of iron impurities in silicon ingots, while improving the whiteness and light transmittance of the crucible; reducing the introduction of iron impurities from multiple links, indirectly increasing the whiteness and light transmittance of the crucible body. On the one hand, it can improve the accuracy of crucible appearance and defect detection, facilitate the promotion of mechanical testing, and improve production efficiency. On the other hand, it can greatly reduce the contamination of silicon ingots by iron elements in the crucible body, improve conversion efficiency, reduce light attenuation, and improve solar cells. efficiency and service life.

Description

technical field [0001] The invention relates to the industry of polycrystalline ingots, in particular to a preparation method for reducing the iron content of a quartz crucible for polycrystalline ingots and improving the light transmittance and whiteness of finished crucibles. Background technique [0002] Traditional polysilicon ingots use fused silica crucible as the main container, and undergo heating, melting, crystal growth, annealing, cooling and other steps under harsh conditions of 1500-1600 °C. The preparation methods of quartz crucible are mainly divided into grouting and coagulation. Both of them need to add fused silica sand to the grinding slurry, or lose water in the plaster mold, or use monomers, initiators, etc. to achieve in-situ solidification. According to the principle of close packing of particles, the existing process ratio adopts the abrasive slurry with small median diameter, the particle size of coarse sand ranges from 10 mesh coarse sand to 40um fi...

AI Technical Summary

Problems solved by technology

[0003] The technical problem to be solved by the present invention is to overcome the grinding slurry with a small median diameter that is often used in the preparation of quartz crucibles in the prior art. The quality of the grinding slurry is not uniform, and it is easy to affect the final quartz due to impurities introduced in the production of the grinding slurry. The quality defect of the crucible provides a way to adjust the existing grinding slurry and directly add quartz sand, improve the process ratio, reduce the introduction of iron impurities from multiple links, and indirectly increase the whiteness and light transmission of the crucible body degree of preparation