Process for recycling waste mortar during solar silicon wafer slicing

Abstract

The invention relates to a process for recycling waste mortar during solar silicon wafer slicing, comprising the following steps of: carrying solid-liquid separation, weighing and adding sand obtained by the solid-liquid separation into a mixed solution of polyethylene glycol containing 2-6% cleaning fluid, stirring for 60-180 minutes according to a program at different mixing speeds, carrying out solid-liquid separation on the mortar, preparing a new cleaning fluid by the separated liquid, adding the separated sand into the mixed solution of polyethylene glycol containing 5-20% surface modifier, fully stirring for 1-2 hours, standing for 6-8 hours in a special storage tank to be subjected to surface modification treatment, packaging with special wet sand packaging bags, and sealing; and carrying out mortar slicing on the separated sand in the packaging bag according to the technological requirement. By adopting the process provided by the invention, the conventional sand washing process is changed, no sewage is discharged, and a green and cyclic regeneration production ideal is met; and the particle size of the recycled separated sand is easy to control, no drying is required, less broken sands are produced in a sorting process, the yield is high, and the application cost is low.

Description

technical field [0001] The invention relates to a process for recycling waste materials in industrial production, in particular to a process for recycling waste mortar from cutting solar silicon wafers. Background technique [0002] With the development of the photovoltaic industry in recent years, solar-grade polysilicon wafers have become upstream resources that major photovoltaic companies are vying for, and the production of polysilicon wafers has become the primary link affecting the photovoltaic industry. The amount of cutting mortar necessary for the production of monocrystalline and polycrystalline silicon wafers has increased significantly. According to statistics, it was 140,000 tons in 2009, and it is expected to reach 200,000-300,000 tons in 2010. [0003] The cutting of solar silicon wafers for photovoltaics generally uses silicon carbide micropowder with high hardness, small particle size and concentrated particle size distribution as the main cutting medium. ...

AI Technical Summary

Problems solved by technology

Among them, the biggest treatment cost is in the treatment process of recycled sand: one is to use several times the weight of recycled sand for acidic / alkaline water washing and multiple rinses, which will generate a large amount of sewage treatment and other environmental protection costs; second, recycled sand The increase in product cost caused by a large amount of investment in environmental protection equipment and operating expenses caused by the large amount of investment in environmental protection equipment and the pollution of surrounding air and environment caused by the grading treatment of sand