A kind of method for recycling chromium in tannery wastewater

A technology for tanning wastewater and chromium recovery, applied in chemical instruments and methods, water/sewage multi-stage treatment, water/sludge/sewage treatment, etc., can solve the problems of inherited gene defects, sensitivity, slow oxidation, etc. The effect of accelerating the sedimentation rate and reducing the sedimentation volume

Active Publication Date: 2017-01-25
CHANGZHOU UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Chromium has high corrosion resistance. In the air, even in the red hot state, it oxidizes very slowly and is insoluble in water; especially hexavalent chromium is a poisonous substance for ingestion / extreme inhalation, and skin contact may Causes sensitivity, more likely to cause hereditary genetic defects, may cause cancer if inhaled, persistent danger to the environment

Method used

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Examples

Experimental program
Comparison scheme
Effect test

example 1

[0028] Firstly, the tannery wastewater is passed into the wastewater with a volume of 5m 3 In the reservoir, filter, precipitate and separate, remove the meat and hair produced in the tannery wastewater, and obtain the wastewater after the preliminary separation; then pass ozone into the wastewater after the preliminary separation, and at the same time add a mass concentration of 30% The hydrogen peroxide is oxidized for 1 hour, so that the chromium salt in the wastewater is oxidized and exists in the form of chromium ions; after being oxidized for a period of time, add 500g of calcium oxide and stir for 10 minutes, and control the temperature at 20°C, stop the stirring reaction for more than 2 hours, and precipitate , stand still; then the above-mentioned sediment and waste water are separated to obtain a wet chromium salt precipitate; then, sulfur dioxide gas is introduced into the above-mentioned chromium salt precipitate, and heated and dried at a temperature of 1000°C; fin...

example 2

[0030] Firstly, the tannery wastewater is passed into the wastewater with a volume of 5m 3 In the reservoir, filter, precipitate and separate, remove the meat and hair produced in the tanning wastewater, and obtain the wastewater after the preliminary separation; then pass ozone into the wastewater after the preliminary separation, and add a mass concentration of 40% at the same time Hydrogen peroxide was oxidized for 2 hours, so that the chromium salt in the wastewater was oxidized and existed in the form of chromium ions; after being oxidized for a period of time, 700g of calcium oxide was added and stirred for 20 minutes, and the temperature was controlled at 30°C, and the stirring reaction was stopped for more than 2.5 hours to precipitate , stand still; then the above-mentioned sediment and waste water are separated to obtain a wet chromium salt precipitate; then, sulfur dioxide gas is introduced into the above-mentioned chromium salt precipitate, and heated and dried at a...

example 3

[0032] Firstly, the tannery wastewater is passed into the wastewater with a volume of 5m 3 In the reservoir, filter, precipitate and separate, remove the meat and hair produced in the tannery wastewater, and obtain the wastewater after the preliminary separation; then pass ozone into the wastewater after the preliminary separation, and add a mass concentration of 50% Hydrogen peroxide is oxidized for 3 hours, so that the chromium salt in the wastewater is oxidized and exists in the form of chromium ions; after being oxidized for a period of time, add 1000g of calcium oxide and stir for 30 minutes, and control the temperature at 40°C, stop the stirring reaction for more than 3 hours, and precipitate , stand still; then the above-mentioned sediment and waste water are separated to obtain a wet chromium salt precipitate; then, sulfur dioxide gas is introduced into the above-mentioned chromium salt precipitate, and heated and dried at a temperature of 1200 °C; finally, the waste wa...

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Abstract

The invention discloses a method for recycling and utilizing chromium in tannery waste water, and belongs to the field of recycling and utilizing of chemical waste water. The method comprises the steps of oxidizing the tannery waste water through an oxidization and aeration mode, and obtaining free-state chromium ions; then enabling the waste water to be alkaline under the action of calcium oxide, generating negative ions OH<->, and quickening the sedimentation speed of the chromium ions; enabling the sedimentary chromium salt mixture to be subjected to reduction reaction under the action of sulfur dioxide gas. According to the method disclosed by the invention, the chromium in the waste water can be effectively recycled, and meanwhile, the waste water which is drained after chromium recycling treatment can meet the national sewage comprehensive emission standard that the concentration of the waste water is less than or equal to 0.1000mg / L.

Description

technical field [0001] The invention discloses a method for recycling chromium in tanning wastewater, belonging to the field of recycling of chemical wastewater. Background technique [0002] Tannery wastewater is the wastewater discharged during the tannery production process. Usually animal hides are salted or soaked in water to make them swell, add lime, remove flesh, dealkalize, and then use tannins or chromium to tan and fatliquify to soften, and finally Dyeing and processing to make leather. The production of tanning industry generally includes degreasing, liming and depilation, softening, tanning, dyeing, drying, finishing and other stages. During the processing, a variety of chemicals need to be added, so that the wastewater contains oil, collagen, animals and plants Fibers, organic and inorganic solids, sulfides, chromium, salts, surfactants, dyes and other pollutants and toxic substances. [0003] Chromium is a silvery-white metal that is extremely hard and resis...

Claims

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Application Information

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Patent Type & AuthorityPatents(China)
IPC IPC(8): C02F9/04
Inventor黄勇余静
OwnerCHANGZHOU UNIV