Preparation method of chrome tanning solution

Abstract

The invention discloses a preparation method of a chrome tanning solution and relates to the technical field of environmental protection. According to the preparation method of the chrome tanning solution, reducing agents such as sodium pyrosulfite, sodium hydrogen sulfite, sodium thiosulfate and the like are reasonably selected for use, high-toxicity sexivalent chromium ions which are not prone to settling separation in chrome mordanting liquid waste are reduced into trivalent chromic ions with lower toxicity under the acidic condition, and the chrome mordanting liquid waste can be environmentally treated simply and effectively; further, the chrome mordanting liquid waste structure obtained after reduction is adjusted by sulfuric acid, formic acid, acetic acid, sodium carbonate and the like, so that the chrome tanning solution with good masking performance and acid and alkali resistant stability is prepared from the chrome mordanting liquid waste, resourceful treatment of the chrome mordanting liquid waste is realized, environmental pollution caused by toxicity of the chrome mordanting liquid waste is reduced, and the preparation method meets the time requirement of sustainable development.

Description

technical field [0001] The invention relates to the technical field of environmental protection, in particular to a preparation method of chrome tanning liquor. Background technique [0002] Chromium mordant dyeing is the most commonly used mordant dyeing method in fur processing. It uses dichromate (sodium dichromate or potassium dichromate) as a mordant, of which potassium dichromate (K 2 Cr 2 o 7 ), commonly known as potassium red alum, is an important oxidant in industrial production and laboratories. [0003] After chrome mordant dyeing is used to process fur, the chrome mordant waste liquid often contains 0.5~2g / L potassium dichromate, 30~50g / L sodium chloride and a small amount of organic weak acid. Among them, the chromium in potassium dichromate mainly exists in the form of hexavalent chromium, if discharged directly, it will cause 5.2×10 5 ~2.7×10 6 mg of hexavalent chromium (calculated on the basis of 4 tons of mordant waste liquid per day), the pollution to ...

AI Technical Summary

Problems solved by technology

Among them, the chromium in potassium dichromate mainly exists in the form of hexavalent chromium, if discharged directly, it will cause 5.2×10 5 ~2.7×10 6 mg of hexavalent chromium emissions (calculated on the basis of 4 tons of mordant waste liquid per day), the pollution to the environment is extremely serious

[0004] Since chromium in chrome mordant waste liquid mainly exists in the form of hexavalent chromium, which is highly toxic, difficult to settle, and has strict emission limits, currently ferrous sulfate is mostly used to reduce hexavalent chromium in chrome mordant waste liquid to trivalent chromium, and then use lime , caustic soda, etc. to make it precipitate, so as to separate it from the water, so as to carry out environmental protection treatment of chromium mordant waste liquid. However, the use of ferrous sulfate can easily lead to an increase in the sludge production of the treated chrome mordant waste liquid. The follow-up sludge treatment caused by this is more difficult and costly. In addition, ferrous salts and iron salts dissolved in water will also increase the chroma of the supernatant of chromium mordant waste liquid sewage, and direct discharge will greatly affect the environment. water quality

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