Harmless treatment method for multi-metal coexisting chromium-containing waste

Abstract

The invention discloses a harmless treatment method for multi-metal coexisting chromium-containing waste. The harmless treatment method comprises the following steps: (1) preparing the multi-metal coexisting chromium-containing waste raw material; (2) pulping the prepared material to prepare mixed pulp, and then adding concentrated sulfuric acid into the mixed pulp; (3) adjusting the pH (potential of Hydrogen) to be 3.5-3.8 by using calcium carbonate to produce iron-chromium-alum precipitate, filtering, wherein the content of Fe in the filtrate is 0.05-0.1 g / L, and the content of the Cr in the filtrate is 0.1-0.5 g / L, and finally recovering other metals by using a conventional means; (4) washing the iron-chromium-alum precipitate under the condition of pH of 6-9 to obtain stable iron, chromium and alum, and detecting leaching toxicity to make sure that the leaching toxicity of total chromium is less than 5 mg / L, the leaching toxicity of Cu is less than 10 mg / L, the leaching toxicity of Zn is less than 10 mg / L, and the leaching toxicity of Ni is less than 5mg / L so as to reach the national harmless standard.

Description

technical field [0001] The invention relates to a harmless recycling method for multi-metal polluted waste, in particular to a harmless treatment method for chromium-containing waste where multi-metal coexists. Background technique [0002] The existing non-ferrous metal hazardous waste treatment technologies include solidification landfill, throwing into the sea, incineration and other technologies. These technologies have disadvantages such as occupying cultivated land, wasting resources, high cost, and potential long-term secondary environmental pollution. The harmless resource treatment technology of non-ferrous metal hazardous waste has always been the focus of research at home and abroad. There are two types of fire technology and wet technology in the prior art. The cost of the former is relatively high, and the main process steps of the existing wet technology include: leaching-solid-liquid separation-purification and enrichment-extraction of metals or compounds. L...

AI Technical Summary

Problems solved by technology

At present, the treatment methods of chromium-containing waste include: wet reduction, fire reduction, solidification and landfill, etc., but they are all mainly for chromium, which will cause waste of resources and increase environmental pressure when multiple metals coexist.

Images