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Method for recycling silica powder and carborundum powder from cut waste mortar

A technology for cutting waste sand and silicon carbide powder, used in metal processing equipment, grinding/polishing equipment, grinding/polishing safety devices, etc. Purity requirements of bulk materials, inability to achieve particle separation, etc., to achieve the effect of high yield

Inactive Publication Date: 2008-02-27
XI AN JIAOTONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In the airflow separation process used in the process, the final sedimentation velocity of the particles is the main factor affecting the airflow separation. In theory, in a stable upflow, the separation of particles based on density cannot be achieved.
Therefore, the purity of the silicon powder recovered by the invention is only 98% by weight, mixed with 2% by weight of silicon carbide, and the obtained silicon powder cannot reach the purity requirements for preparing monocrystalline silicon or polycrystalline silicon block materials, which reduces the recovery of silicon powder ability to use

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0015] Multi-wire cutting manufactures silicon wafers for solar energy and integrated circuits. The dispersant in the abrasive mortar used is oily. The composition of the waste mortar is 44% by weight of dispersion liquid, 48% by weight of silicon carbide abrasive grains, 6.4% by weight of silicon, and 1.6% by weight of metal. weight%. Take 1 ton of waste cutting mortar, first centrifuge the waste mortar, put 550 kg of the obtained sediment into a container, soak and wash with acetone, and obtain 540 kg of powder through centrifugation. Roll the obtained powder and pass it into the air flow flotation machine to obtain 63kg of silicon powder and 470kg of silicon carbide-metal mixed powder. Put the silicon powder into the container further, add dibromomethane-alcohol mixed solution (density is 2.40g / cm 3 ), and use ultrasonic vibration for 10 minutes, stand still for 20 minutes, recover the floating matter above, and carry out washing and separation. The obtained silicon powde...

Embodiment 2

[0017] Multi-wire cutting manufactures silicon wafers for solar energy and integrated circuits. The dispersant in the abrasive mortar used is oily. The composition of the waste mortar is 44% by weight of dispersion liquid, 48% by weight of silicon carbide abrasive grains, 6.4% by weight of silicon, and 1.6% by weight of metal. weight%. Take 1 ton of waste cutting slurry, first centrifuge the waste, put 550 kg of the obtained sediment into a container, soak and wash with acetone, and obtain 540 kg of powder through centrifugation. Roll the obtained powder and pass it into the air flow flotation machine to obtain 63kg of silicon powder and 470kg of silicon carbide-metal mixed powder. Put the silicon powder into the container further, add calcium bromide aqueous solution (density is adjusted to 2.40g / cm 3 ), and use ultrasonic vibration for 10 minutes, stand still for 15 minutes, recover the floating matter above, and carry out washing and separation. Put the obtained silicon p...

Embodiment 3

[0019] Multi-wire cutting manufactures silicon wafers for solar energy and integrated circuits. The dispersant in the abrasive mortar used is oily. The composition of the waste mortar is 44% by weight of dispersion liquid, 48% by weight of silicon carbide abrasive grains, 6.4% by weight of silicon, and 1.6% by weight of metal. weight%. Take 1 ton of waste cutting slurry, first centrifuge the waste, put 540 kg of the obtained sediment into a container, soak and wash with acetone, and obtain 530 kg of powder through centrifugation. Roll the obtained powder and pass it into the air flow flotation machine to obtain 62kg of silicon powder and 460kg of silicon carbide-metal mixed powder. Put the silicon powder into the container further, add tribromomethane-alcohol mixed solution (density is adjusted to 2.45g / cm 3 ), and use ultrasonic vibration for 10 minutes, stand still for 30 minutes, recover the floating matter above, and carry out washing and separation. Put the obtained sil...

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PUM

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Abstract

The invention discloses an extracting method of high-purity silicon powder and carborundum powder from waste slurry of monocrystalline silicon cutting or grinding course, which comprises the following steps: separating solid from liquid for the waste slurry; using organic solvent to remove suspending agent and adhesive; doing gas float for solid sand; obtaining certain purity silicon powder; doing liquid float and gravity sorting for the silicon powder further; acidifying the silicon powder through acid; obtaining high-purity silicon powder; doing magnetic float for the composite powder of carborundum-metal through gravity; obtaining the pure carborundum powder. The invention can recycle high-purity silicon from waste slurry in the silicon bar cutting manufacturing course effectively, which changes waste into value with high receiving rate to solve the problem of resource shortage of high-purity silicon.

Description

technical field [0001] The invention relates to a method for extracting high-purity silicon powder and silicon carbide powder from waste mortar produced by cutting or grinding silicon wafers of monocrystalline silicon or polycrystalline silicon rods. Background technique [0002] The cutting and preparation of thin sheet products of substrates for integrated circuits and solar cell substrates adopts the principle of multi-wire cutting, and steel wires are used to drive a mortar composed of silicon carbide abrasives to cut high-purity monocrystalline silicon or polycrystalline silicon rods. Although this kind of mortar can be recycled, as the cutting process progresses, silicon shavings and a small amount of steel wire shavings are mixed into the mortar, which reduces the cutting performance of the mortar and deteriorates the precision of the obtained silicon wafer. Mortar, and add new mortar. These old mortars are generally discarded. But the precious high-purity silica fu...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B24B55/12
Inventor 杨建锋高积强陈畅杨军张文辉
Owner XI AN JIAOTONG UNIV
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