Novel method for chrome tanning wastewater treatment and chrome recycling

Abstract

A novel method for chrome tanning wastewater treatment and chrome recycling comprises two parts of chrome tanning wastewater treatment and chrome recycling, wherein chrome tanning wastewater treatment is implemented as follows: the chrome tanning wastewater is subjected to homogenization and quantification in a collection tank and then pumped by a pump into a pretreatment system for removal of fur residues, leather chips, protein, dyes and other impurities; the chrome tanning wastewater after impurity removal enters an ionic exchange fiber system for exchange and adsorption, and effluent with total chrome and hexavalent chrome up to the standard is recycled as washing water for the leather tanning procedure or enters a follow-up treatment system for up-to-standard discharge; ionic exchange fibers are regenerated with a regeneration solution after being adsorbed and saturated, and the regenerated ionic exchange fibers are used for circularly treating the chrome tanning wastewater. Recycling of chrome is implemented as follows: a chrome sulphate solution obtained through regeneration and a sodium bichromate concentrated solution are taken as raw materials for preparation of a chrome tanning agent, namely, basic chrome sulphate; the prepared chrome tanning agent is used for leather tanning, so that chrome in the chrome tanning wastewater is effectively recycled. By means of the process, chrome in the chrome tanning wastewater is effectively recycled while stable and up-to-standard discharge of total chrome and hexavalent chrome is guaranteed. The process adopts a simple route, is low in energy consumption and high in chrome recycling rate, causes no secondary pollution and has good economic and social benefits.

Description

technical field [0001] The invention belongs to the technical field of industrial wastewater treatment and recycling, and relates to a method for treating wastewater containing hexavalent chromium and total chromium and recycling chromium, in particular to a new method for treating wastewater from chrome tanning and recycling chromium. Background technique [0002] Chrome tanning wastewater is defined as "waste chrome liquor and corresponding washing process wastewater generated in chrome tanning, chrome retanning and subsequent processes". Chrome tanning wastewater is one of the most polluted wastewater in tannery (skimming wastewater, dehairing and liming wastewater and chrome tanning wastewater), and it is the only heavy metal pollution among them. [0003] In the actual production process, there are three main streams of chrome tanning wastewater: the chromium-containing wastewater produced by the chrome tanning process contains 3000-4000 mg / L of chromium, accounting for...

AI Technical Summary

Problems solved by technology

The application of the first two methods is relatively mature, but there are limitations: one is that the alkali precipitation method occupies a large area, the dosage of chemicals is large, and it is difficult to reach the standard stably; the other is that it will produce a large amount of waste chromium residue. Cause secondary pollution; the third is that metal chromium cannot be effectively recovered, resulting in waste of resources

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