Method for processing chrome-containing tanned wastewater and recycling chrome metal

Abstract

The invention discloses a method for processing chrome-containing tanned wastewater and recycling chrome metal. The method comprises the steps of simply preprocessing the tanned wastewater to remove solid impurities; putting a chrome-containing tanned waste liquor with the solid impurities removed in a hull cell, adding a small amount of carbamide, a proper amount of boric acid and methyl alcohol to adjust pH; taking an iridium-plated DSA (Dimensionally Stable Anode) polar plate as a positive pole, taking a plated part which is deoiled and polished before the plated is plated as a negative pole, and placing the positive pole and the negative pole in an electroplating bath; connecting a pulse power supply; adjusting the space between polar plates to be 7.5cm and adjusting voltage so that the potential of the negative pole electrode is kept between -0.96V and -1.1V, and the current density is 8-35A / dm<2>; and mechanically stirring and electrolyzing. Compared with the existing alkali precipitation technology, the method provided by the invention has the advantages that the content of Cr in produced water of the chrome-containing tanned wastewater processed by the method is obviously reduced; the content of chrome in the wastewater can be greatly reduced; the metal chrome can be recycled; and the problems of a large amount of chrome-containing sludge and high treatment cost in the existing tanned wastewater alkali precipitation technology can be solved.

Description

technical field [0001] The invention relates to a method for treating chromium-containing tanning wastewater and recovering metal chromium. Background technique [0002] The wastewater produced in the leather tanning section is acidic and contains a large amount of trivalent chromium, chloride, formate and other masking agents, as well as hydrolyzed products of collagen. Since chromium belongs to a class of priority pollutants, the chromium-containing tanning wastewater must be treated separately, and can only enter the comprehensive wastewater for centralized treatment after reaching the corresponding discharge standards. The resulting chromium-containing sludge must be handed over as hazardous solid waste. Departments with processing qualifications conduct specialized harmless disposal. The existing tanning wastewater treatment technology is mainly alkali precipitation method. This method has low treatment cost and simple operation. This method can effectively remove chro...

AI Technical Summary

Problems solved by technology

[0003] In recent years, with the continuous innovation of tanning technology and the market's demand for leather products, the types of new chemicals in the chrome tanning process have gradually increased. Complex, in which a large number of organic compounds will form stable chelates with chromium ions, so that the precipitation of chromium ions and alkali cannot effectively remove the chromium in the tanning wastewater, and there will still be a certain amount of chromium in the waste liquid. After treatment, the effluent is difficult to meet the standard, resulting in excessive chromium content in the sludge generated in the subsequent wastewater treatment process, which turns general solid waste into hazardous waste, and the resulting environmental risks increase sharply. It is urgent to develop new types of chromium-containing tanning wastewater Treatment technology to achieve a substantial reduction in chromium sludge, directly realize resource utilization of chromium in the wastewater treatment process, and reduce disposal costs