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Silicon wafer processing wastewater treatment method and device thereof

A technology for processing wastewater and treatment methods, which is applied to the treatment of sewage or sludge, water, and wastewater, and can solve problems such as high treatment costs, waste of resources, and consumption of acid-base resources.

Pending Publication Date: 2020-07-14
JIANGSU JIUWU HITECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This will cause a large consumption of acid and alkali resources, waste of resources, high processing costs and other problems

Method used

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  • Silicon wafer processing wastewater treatment method and device thereof
  • Silicon wafer processing wastewater treatment method and device thereof
  • Silicon wafer processing wastewater treatment method and device thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0070] The silicon wafer alkali etching liquid flushing waste water is 100m³, the KOH concentration in the feed is 6%-7%, and the potassium silicate concentration is 13000mg / L. Enter the microfiltration membrane system at a temperature of 30°C, adopt cross-flow filtration, control the membrane surface flow velocity at 3-5m / s, the pore size of the microfiltration membrane is 200nm, and the operating pressure is controlled at 0.2Mpa. The recovery rate is 95%, and the microfiltration membrane supernatant enters the first-stage nanofiltration membrane system with an operating pressure of 2MPa and a temperature of 30-40°C. When the concentration of potassium silicate is above 30000 mg / L, the concentrated liquid enters the secondary nanofiltration membrane system to continue separation and concentration. The operating pressure of the secondary nanofiltration membrane is 3MPa and the temperature is 35-40°C. The membrane filtrate of the first-level membrane separation system and the s...

Embodiment 2

[0072] The silicon wafer alkali etching liquid flushing wastewater is 100m³, the KOH concentration in the feed is 6%-7%, and the potassium silicate concentration is 13500mg / L. Enter the microfiltration membrane system at a temperature of 35°C, adopt cross-flow filtration, control the membrane surface flow velocity at 3-5m / s, the pore size of the microfiltration membrane is 50nm, and the operating pressure is controlled at 0.3Mpa. The recovery rate is 92%, and the microfiltration membrane supernatant enters the first-stage nanofiltration membrane system with an operating pressure of 2MPa and a temperature of 30-40°C. When the concentration of potassium silicate is above 30000 mg / L, the concentrated liquid enters the secondary nanofiltration membrane system to continue separation and concentration. The operating pressure of the secondary nanofiltration membrane is 3MPa and the temperature is 35-40°C. The membrane filtrate of the first-level membrane separation system and the sec...

Embodiment 3

[0074]The silicon wafer alkali etching liquid flushing waste water is 100m³, the KOH concentration in the feed is 6%-7%, and the potassium silicate concentration is 13000mg / L. First, add flocculant polyacrylamide 75mg / L to carry out flocculation reaction. After the reaction, after natural settlement, the settled clear liquid enters the microfiltration membrane system at a temperature of 30°C, adopts cross-flow filtration, and the flow velocity of the membrane surface is controlled at 3-5m / s, the pore size of the microfiltration membrane is 200nm, and the operating pressure is controlled at 0.2Mpa. The recovery rate is 95%, and the microfiltration membrane supernatant enters the first-stage nanofiltration membrane system with an operating pressure of 2MPa and a temperature of 30-40°C. When the concentration of potassium silicate is above 30000 mg / L, the concentrated liquid enters the secondary nanofiltration membrane system to continue separation and concentration. The operati...

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Abstract

The invention relates to a process for recycling silicon wafer alkaline etching solution flushing wastewater and a method thereof, in particular to a process for purifying alkali liquor containing potassium hydroxide, potassium silicate and organic matters, which belongs to the technical field of three-waste treatment. The device comprises a solid-liquid separation membrane filtration system and ananofiltration membrane filtration system. The solid-liquid separation membrane filtration system is positioned at the front end of the nanofiltration membrane filtration system. The solid-liquid separation membrane filtration system comprises but is not limited to a ceramic solid-liquid separation membrane, a tubular solid-liquid separation membrane, a plate-type solid-liquid separation membrane, a hollow fiber membrane and the like. The nanofiltration membrane filtration system comprises but is not limited to a roll type nanofiltration membrane. Two stages of nanofiltration membranes are arranged. The membrane filtration system is provided with a plurality of valves for adjusting the operation pressure and the water inlet and outlet flow of the system and backwashing, chemical cleaningand the like of the solid-liquid separation membrane. The device has the advantages of being good in filtering effect, high in automation degree, high in adaptability, small in occupied area and the like, and therefore the device is particularly suitable for recycling silicon wafer alkaline etching solution flushing wastewater.

Description

technical field [0001] The present invention relates to a recovery process and method of silicon wafer alkali etching liquid washing wastewater, more specifically relates to a silicon wafer alkaline etching liquid washing wastewater treatment process containing potassium hydroxide, potassium silicate, silicon powder and organic matter, belonging to The technical field of treatment of water, waste water, sewage or sludge. Background technique [0002] In the production process of monocrystalline and polycrystalline silicon wafers, it is necessary to cut the ingot into required silicon wafers. After the silicon wafer is cut, it needs to be marked, chamfered and polished. Before the silicon wafer can be polished, the slice damage must be removed. Next, the silicon wafer needs to be etched to remove the damage caused by the grinding wafer. Grinding is the use of abrasive sand to remove material and damage from the previous step on the surface of the silicon wafer. During th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F9/04C01D1/28C01D1/38C01B33/037C01B33/02C02F101/10C02F101/30
CPCC02F1/44C02F1/442C02F1/66C02F1/444C02F9/00C01D1/28C01D1/38C01B33/02C01B33/037C02F2101/10C02F2101/30C02F1/56
Inventor 罗小勇吴正雷王磊刘乐天董凯钟志君庄力杨晓明彭文博范克银党建兵
Owner JIANGSU JIUWU HITECH