Method for recycling and utilizing chromium in tannery waste water

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

Active Publication Date: 2015-10-07
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] First, pass the tanning wastewater into the wastewater with a volume of 5m 3 In the reservoir, filtering, precipitation and separation are carried out to remove the meat pieces and hairs produced in the tannery wastewater to obtain the wastewater after preliminary separation; then, ozone is introduced into the wastewater after the preliminary separation, and the mass concentration is 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 a period of oxidation, 500 g of calcium oxide is added and stirred for 10 minutes, and the temperature is controlled at 20 ° C, the stirring reaction is stopped for more than 2 hours, and the precipitate is precipitated. , let stand; then separate the above-mentioned precipitate and waste water to obtain a wet chromium salt precipitate; then pass sulfur dioxide gas into the above-mentioned chromium salt precipitate, and heat and dry at a te...

example 2

[0030] First, pass the tanning wastewater into the wastewater with a volume of 5m 3 In the reservoir, filtering, precipitation and separation are carried out to remove the meat pieces and hairs produced in the tannery wastewater to obtain the wastewater after preliminary separation; then, ozone is introduced into the wastewater after the preliminary separation, and the mass concentration is 40%. The hydrogen peroxide is oxidized for 2 hours, so that the chromium salt in the waste water is oxidized and exists in the form of chromium ions; after a period of oxidation, 700 g of calcium oxide is added and stirred for 20 minutes, and the temperature is controlled at 30 ° C, the stirring reaction is stopped for more than 2.5 hours, and precipitation , let stand; then separate the above-mentioned precipitate and waste water to obtain a wet chromium salt precipitate; then pass sulfur dioxide gas into the above-mentioned chromium salt precipitate, and heat and dry at a temperature of 11...

example 3

[0032] First, pass the tanning wastewater into the wastewater with a volume of 5m 3 In the reservoir, filtering, precipitation and separation are carried out to remove the meat pieces and hairs produced in the tannery wastewater to obtain the wastewater after preliminary separation; then, ozone is introduced into the wastewater after the preliminary separation, and the mass concentration is 50%. The hydrogen peroxide is oxidized for 3 hours, so that the chromium salt in the waste water is oxidized to exist in the form of chromium ions; after a period of oxidation, 1000 g of calcium oxide is added and stirred for 30 minutes, and the temperature is controlled at 40 ° C, the stirring reaction is stopped for more than 3 hours, and the precipitate is precipitated. Then, the above-mentioned precipitate 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 at a temperature ...

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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 tannery wastewater, which belongs to the field of chemical wastewater recycling. Background technique [0002] Tanning wastewater is the wastewater discharged from the tanning production process. Usually animal skins are salted or soaked in water to make them swell, limed, fleshed, dealkalized, then softened with tannin or chrome, tanned and fatliquored. Dyed to make leather. The production of tanning industry generally includes degreasing, liming, dehairing, softening, tanning, dyeing, drying, finishing and other sections. During the processing, various 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 silver-white metal that is extremely hard and corrosion-resistant. Density 7.20g / cm3. Soluble in s...

Claims

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Application Information

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