Decolorization method of polyethylene glycol for crystal silicon wafer cutting fluid

Abstract

The invention belongs to the field of regeneration technology of wafer cutting liquid polyethylene glycol and in particular relates to a decolorizing method of wafer cutting liquid polyethylene glycol. The decolorizing method comprises the following steps: (1) adding the wafer cutting waste liquid and active carbon into a container; (2) heating, controlling the liquid temperature to be 30-60 DEG C, while continuously stirring and continuously introducing compressed air into the container to uniformly mix cutting waste liquid with active carbon to obtain mixed liquid; (3) introducing the mixed liquid into a filter tank for filtering, and collecting filter liquor to obtain finished polyethylene glycol after recovery. According to the decolorizing method, the electrical conductivity and the chromaticity of recovered polyethylene glycol are greatly reduced; the decolorizing method has the advantages of low energy consumption, low pollution, short treatment cycle, high decolorizing speed, low raw and auxiliary material consumption and high efficiency; the loss of polyethylene glycol is avoided.

Description

technical field [0001] The invention belongs to the technical field of regeneration of polyethylene glycol for crystal silicon wafer cutting fluid, and in particular relates to a method for decolorizing polyethylene glycol for crystal silicon wafer cutting fluid. Background technique [0002] Polyethylene glycol (PEG), as one of the main components of crystalline silicon wafer cutting fluid used in the current photovoltaic industry, plays the role of dispersing, lubricating, cooling, and suspending in the multi-wire sawing process of solar crystalline silicon wafers, and can effectively reduce silicon It prevents wafer cutting damage and makes silicon wafers easy to clean. However, when the cutting fluid is used to a certain extent, it needs to be separated and purified to remove impurities such as metal particles and silicon sawdust produced during the cutting process of the wire saw, improve the purity of the regenerated cutting fluid, reduce its chroma and conductivity, a...

AI Technical Summary

Problems solved by technology

But the scheme still has the following problems: (1) It needs to add acid and pickle with water, that is, first artificially add water to make it mix, and finally use distillation to remove the previously added water, and distillation is a kind of high energy consumption. measures, and in today's increasingly scarce water resources, this technical solution is also a big problem for water consumption; (2) In fact, in the process of distillation, part of polyethylene glycol also evaporates with water vapor, resulting in polyethylene glycol The loss of diol reduces the recovery rate of polyethylene glycol; (3) After distillation, the COD content in the water increases (polyethylene glycol is an organic polymer, and it is miscible with water, causing the COD content in the water to be extremely high. Even reach COD10000mgO 2 / L or more, while the national standard stipulates that COD in water should not exceed 50mgO 2 / L is regarded as reaching the standard), forming waste water, and the simple treatment of the waste water according to its method cannot make the COD in the water reach the standard, causing water pollution and serious environmental protection pressure; (4) ion exchange resin will cause consumption, Coupled with the use of acid, alkali and water, the consumption of raw and auxiliary materials is high and the cost is high; even if the ion exchange resin can be regenerated, resin regeneration usually requires a large amount of water or even pure water and additional acid and alkali , salt and other auxiliary materials to regenerate them will also cause high consumption of raw and auxiliary materials and the generation of waste water; (5) Even if the technical plan mentions that water can be recycled as industrial production water, it will not be recycled infinitely in industry Use, to a certain extent, must also treat wastewater, causing water pollution or bringing pressure on environmental protection, and industrial production water itself is a kind of wastewater; (6) The distillation process usually takes a long time, resulting in a decline in production efficiency ; (7) Long process, complex process, long production processing cycle, slow speed and low efficiency