Method of recycling cutting suspension

A suspension and solid-liquid separation technology, which is applied to the used abrasive processing device, abrasive, metal processing equipment, etc., can solve the problems that the cutting mortar cannot be recycled, the production efficiency is affected, and the performance of the cutting mortar cannot be used again.

Inactive Publication Date: 2007-09-12
PRECISION RECYCLING TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

First of all, this treatment method can only remove part of the finely divided silicon carbide particles and free silicon powder in the waste mortar system, but there are still a considerable proportion of finely divided particles in the recycled mortar obtained after treatment, and the added particles in the system cannot be removed. Moisture is removed so recycled mortar does not maintain the same performance and stability as brand new cutting mortar
Secondly, this treatment method cannot remove metal impurities in the system and silicon micropowder attached to the surface of silicon carbide particles, so the recycled silicon carbide mortar after treatment cannot be directly recycled, and 30-50% of new silicon carbide micropowder and 20-30% new suspension based on polyethylene glycol (PEG) can be used again for cutting
Third, although the recovered mortar can be used for cutting again after adding some new materials, but because it still contains a large amount of metal and silicon micropowder impurities and too much water, the cutting efficiency and the sanding ability of the suspension (system viscosity) Compared with the new cutting mortar

Method used

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  • Method of recycling cutting suspension

Examples

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Effect test

Embodiment 1

[0029] An example of using the present invention to process the cutting mortar prepared by JIS800 type silicon carbide micropowder and PEG300 type suspension in a ratio of 0.95:1 to complete the single crystal slicing process.

[0030] The uniformly stirred waste mortar is filtered out of the liquid suspension through a vacuum filter, and the filtrate is collected. Mix the filtrate with a polyacrylamide aqueous solution with a concentration of 0.1% at a ratio of 1:0.03 and stir evenly. After solid flocs appear in the mixed solution, input it into a disc centrifuge, and adjust the inlet pressure of the disc centrifuge at 0.15Mpa, the separation factor is set to 6500, so that the solid content is less than or equal to 5%, and the filtrate product is collected. Input the collected filtrate into a precision filter equipped with a filter element group of less than 1 μm, adjust the inlet pressure of the filter at 0.3Mpa so that the solid content is ≤0.01%, and collect the filtrate. ...

Embodiment 2

[0032] An example of using the present invention to process the cutting mortar prepared by JIS800 type silicon carbide micropowder and PEG400 type suspension in a ratio of 0.95:1 to complete the single crystal slicing process.

[0033] The uniformly stirred waste mortar is filtered out of the liquid suspension through a vacuum filter, and the filtrate is collected. Mix the filtrate and diatomaceous earth at a ratio of 1:0.3 and stir evenly, then input it into a plate filter to make the solid content ≤ 5%, and collect the filtrate product. Input the collected filtrate into a precision filter equipped with a filter element group of less than 1 μm, adjust the inlet pressure of the filter at 0.2Mpa so that the solid content is ≤0.01%, and collect the filtrate. Put the filtrate into a vacuum drying oven to fully dry and concentrate, the temperature is less than 160°C, take it out after the moisture reaches the specified ≤0.5%, and place it in a dry environment to cool to room tempe...

Embodiment 3

[0035] An example of using the present invention to treat cutting mortar prepared by JIS1200 type silicon carbide micropowder and PEG300 type suspension in a ratio of 0.95:1 to complete the single crystal slicing process.

[0036] The uniformly stirred waste mortar is filtered out of the liquid suspension through a vacuum filter, and the filtrate is collected. Mix the filtrate with a carboxymethylcellulose aqueous solution with a concentration of 3% in a ratio of 1:0.05 and stir evenly. After solid flocs appear in the mixed solution, it is input into a series connection composed of a filter press and a disc centrifuge. For the filter unit, adjust the inlet pressure of the disc centrifuge to 0.1Mpa, set the separation factor to 8000, make the solid content ≤ 5%, and collect the filtrate product. The collected filtrate is input into a precision filtration device equipped with a microfiltration membrane module, and the inlet pressure of the filtration device is adjusted to mainta...

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Abstract

The waste cutting suspension recovering process features that the waste linear cutting sand pulp from silicon chip processing is multiple stage treated through the steps of solid-liquid separation, initial filtering of the suspension, final filtering of the suspension, and concentrating and drying of the suspension. The process has recovered polyethylene glycol-base or oil-base suspension possess performance the same as or near that of new material and capacity of being reused. The present invention raises material using efficiency, lowers silicon chip producing cost and avoids environmental pollution caused by exhausting waste linear cutting sand pulp.

Description

technical field [0001] The invention relates to a method for recycling cutting waste suspension. Specifically, the wire-cutting waste mortar in the silicon wafer processing technology is treated by physical and chemical methods, and the suspension therein is recovered for the purpose of reuse. Background technique [0002] During the processing of silicon wafers, cutting silicon rods into sheets of different diameters and thicknesses through special wire cutting equipment is currently a common processing method in the world. In this cutting process, it is necessary to use silicon carbide micropowder with high hardness, small particle size and concentrated particle size distribution as the main cutting medium. In order to disperse the silicon carbide powder evenly during the cutting process and take away the huge frictional heat generated during the cutting process in time, it is usually necessary to add the silicon carbide powder to a polyethylene glycol (PEG) base or oil i...

Claims

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Application Information

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IPC IPC(8): B24C9/00
CPCY02P70/10
Inventor 张捷平
Owner PRECISION RECYCLING TECH CO LTD
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