Method for recycling exhausted exchange resin during recovering process of silicon wafer wire cutting liquid

Abstract

A method for recycling exhausted exchange resin during the recovering process of a silicon wafer wire cutting liquid belongs to the field of silicon wafer wire cutting, mainly comprises the following steps: 1) water washing, 2) acid soaking, 3) reagent mixture soaking, 4) oxidant soaking, and 5) water curing for standby application, and solves the problem that after being exhausted, rubber in the silicon wafer wire cutting liquid recovery industry is difficult to recover. Macromolecular organics in impurities are oxidized into micromolecular organics through the introduction of a strong oxidant, that is, NaClO, and under the high-speed mixing condition, the separation from resin is enabled to be relatively easy. Due to short contact time and reasonable temperature control, no damage on the body and exchange groups of the resin is caused. The method aims to obviously recover the ion exchange properties after ion exchanger resin is exhausted, which is caused by metal ions, soluble metal complexes, soluble silicide, organics and the like, and then is recovered. Through the experimental detection and the field practice, the properties of the recovered ion exchange resin are kept, and the exchange capacity reaches the new resin level basically.

Description

technical field [0001] The invention belongs to the field of silicon wafer wire cutting, and in particular relates to a method for reusing invalid ion exchange resins during the recovery process of silicon wafer wire cutting fluid. Background technique [0002] The main component of silicon wafer wire cutting fluid is polyethylene glycol 200, referred to as PEG. The main function in the photovoltaic industry is to mix it with SIC particles with high hardness and organic additives in a certain proportion to obtain silicon wafer wire cutting mortar. This mortar is adsorbed on the steel wire, and with the high-speed movement of the steel wire, it forms a strong cutting ability, and performs multi-wire cutting on the silicon wafer, so as to obtain monocrystalline silicon wafers or polycrystalline silicon wafers for solar energy. [0003] The silicon wafer cutting mortar mentioned above is mixed with tiny silicon powder cut from the silicon wafer, iron ions from the wear of the s...

AI Technical Summary

Problems solved by technology

It needs to be removed by ion exchange resin, otherwise the recovered cutting fluid can not meet the requirements for use. Usually, the recovery of 50-120 times the volume of the resin needs to be regenerated to restore the resin to the normal working level. However, due to the impurities contained in the recovered fluid After the accumulation of substances for a certain period of time, the resin exchange capacity will be reduced and cannot be regenerated and restored, making the ion exchange resin invalid

Especially the anion resin, the appearance of the gel resin becomes black or dark, and the appearance of the macroporous resin becomes gray, which basically has no exchange ability, which affects the index of the finished wire cutting fluid, thus affecting the cutting of silicon wafers

However, the resin regeneration and recovery methods recorded in the relevant materials have cumbersome operation steps and the resin that has failed in this industry has little effect after recovery. Usually, the resin needs to be replaced within 6-10 months, which will increase the purchase cost of the enterprise and cause environmental pollution