Process and device for treating and recycling chromium-containing waste liquor

Abstract

The invention discloses a process for treating and recycling chromium-containing waste liquor and belongs to the technical field of treatment of industrial sewage. The process comprises the following steps of: diluting organic amine (trialkyl tertiary amine) in a solvent, wherein the diluted organic amine is used as an extracting agent, adjusting the acidity of the pre-treated chromium-containing waste liquor to be appropriate, and performing counter-current extraction on a multi-stage mixing-clarification box type extraction tank; extracting chromium (VI) into an organic phase (an O phase), and after the content of chromium (VI) in raffinate (a water phase and an A phase) reaches the national wastewater discharge standard, namely the content of the chromium (VI) in raffinate is 0.2mg / L (which meets GB21900-2008 discharge limit requirement), discharging; and adjusting the phase ratio of the A phase to the O phase to ensure that the flow of the A phase is greater than that of the O phase so as to enrich the chromium (VI) in the organic phase in the extraction process, wherein the enrichment magnification can reach more than ten times. By the process, the chromium-containing waste liquor is treated and recycled. The environment-friendly problem that pollutant which does not reach the standard is discharged is solved for small and medium electroplating and tanning enterprises, equipment for treating waste liquid is eliminated, the running cost of the equipment is saved, and production cost is reduced, and clean production is realized.

Description

Technical field [0001] The invention belongs to the technical field of industrial sewage treatment, and specifically relates to a process for the disposal and recovery of waste liquid containing chromium (VI) and a disposal and recovery device thereof. Background technique [0002] Chromium (VI) is needed in industries such as cold-rolled sheet passivation, chemical electroplating, and leather tanning, which will produce a large amount of chromium (VI) waste liquid. Chromium (VI) is one of the highly toxic elements. Direct discharge can cause serious pollution to the environment. Human contact or ingestion can cause serious damage such as skin ulcers, respiratory inflammation, anemia, neuritis, etc. It is also one of the known carcinogens . [0003] At present, the harmless treatment of waste liquid containing chromium (VI) is mainly chemical reduction, sedimentation and then storage and landfill. If the treated waste slag containing chromium (III) is discharged or landfilled, in...

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Problems solved by technology

For some small and medium-sized electroplating and tanning enterprises, due to their small scale, the amount of chromium-containing waste liquid produced is relatively small. Therefore, the construction of sewage treatment equipment requires relatively large investment, high operation and management costs, and the pollution control burden of enterprises is relatively large. Heavy

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