Zero-emission process of nickel hydrometallurgy wastewater containing heavy metals, oil and high-concentration mixed salts

Abstract

The invention discloses a zero-emission process of nickel hydrometallurgy wastewater containing heavy metals, oil and high-concentration mixed salts. The wastewater contains the heavy metals, the high-concentration mixed salts (carbonates and sulfates) and a small amount of oil substances (solvent oil and an extracting agent). The method comprises the following steps: firstly, removing oil by carrying out adsorption by special resin, then preliminarily adjusting the pH value of the wastewater, removing heavy metal ions which are mainly nickel ions in the wastewater through a heavy metal capturing agent, removing precipitations, adjusting the pH value of the wastewater to be acidic to completely convert the carbonates in the wastewater into sulfates, then carrying out precise filtering to remove insoluble fine particles in the wastewater to obtain a relatively pure sodium sulfate solution, finally, concentrating the wastewater by high-pressure reverse osmosis, reusing the water producedby a membrane for production, and recovering anhydrous sodium sulfate from the obtained concentrated brine by mechanical vapor recompression (MVR) or multi-effect evaporation. According to the invention, the treatment problem of the nickel hydrometallurgy wastewater which has a complex system and contains heavy metals, high-concentration composite salts and a small amount of oil is effectively solved, and meanwhile, recycling and zero emission of the salts in the wastewater are realized.

Description

technical field [0001] The invention belongs to the technical field of treatment of complex high-salt system industrial wastewater, salt recovery and zero discharge, and specifically relates to a complex system nickel hydrometallurgy containing heavy metals, oily substances and high-concentration mixed salts (carbonates and sulfates) Wastewater resource recovery and zero discharge process. Background technique [0002] Industrial wastewater containing heavy metals, oil and high-concentration mixed salts (carbonates and sulfates) comes from the leaching-extraction stripping-electrowinning hydrometallurgical extraction process of metallic nickel. process, especially the nickel sulfate solution containing organic matter obtained through extraction and stripping, and in the nickel electrowinning process, due to the increase in acidity of the anolyte, to maintain production, it is necessary to adjust the alkali and neutralize it. After a large amount of recycling, the sodium in t...

AI Technical Summary

Problems solved by technology

[0009] For the problems existing in the prior art, the object of the present invention is to provide a kind of complex system nickel wet method containing heavy metal, high concentration mixed salt (carbonate and sulfate) and a small amount of oily substance (solvent oil and extraction agent) Zero discharge process of metallurgical wastewater. This process not only effectively solves the problem of nickel hydrometallurgical wastewater treatment in complex systems containing heavy metals, high-concentration compound salts and a small amount of oil, but also truly realizes the resource utilization and zero discharge of salt in wastewater.

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