Method for selectively recovering heavy metals in electroplating sludge by using chlorination roasting approach

Abstract

The invention belongs to the technical field of solid waste treatment and discloses a method for selectively recovering heavy metals in electroplating sludge by using a chlorination roasting approach.The method comprises the followings steps that the electroplating sludge and a chlorinating agent are mixed and then roasted at 159-400 DEG C, volatile chromium chloride is collected through tail gasand absorbed by water to obtain a chromium chloride solution, water is added to dissolve residual solid materials, and solid-solution separation is carried out to obtain a metal chloride mixed solution and solid sludge slag. According to the method, the electroplating sludge is treated in combination with a chlorination roasting technology in industrial metallurgy, through using hydrochloric acidas the chlorinating agent, the recovery rate of chromium in the electroplating sludge can reach more than 85% or above, the recovery rate of nickel and the recovery rate of copper can reach more than90% or above, the process is simple, the recovery effect is good, and the method has relatively high environment and economic benefits, and is beneficial to resource utilization of the electroplatingsludge.

Description

technical field [0001] The invention belongs to the technical field of solid waste treatment, and in particular relates to a method for selectively recovering heavy metals in electroplating sludge by a chlorination roasting method. Background technique [0002] Electroplating sludge is a toxic and harmful hazardous solid waste produced in the production process of the electroplating industry, including the sludge produced by the dissolution of anodes in the electrolytic cell, the sludge obtained by filtration, and the sludge produced when the chemical-precipitation method is used to treat wastewater. The content of nickel, copper, chromium, zinc and other metals in electroplating sludge is very high, so it is very necessary to recover valuable metals from electroplating sludge. At present, the treatment method of electroplating sludge is inappropriate, and it is discarded in the open field. Because the physical and chemical properties of these sediments are not very stable,...

AI Technical Summary

Problems solved by technology

[0004] Chinese patent "treatment method of electroplating sludge" (CN201810278358.9) Add compound additives to electroplating sludge, stir under ultraviolet light, then add coke powder, mix well, press filter, crush and dry the mud cake , placed at a temperature of 1100-1200°C for smelting treatment, the exhaust gas produced by smelting is purified and discharged, and the smelted materials are refined and separated to obtain molten slag and metal alloys; but this method requires Consumes a lot of heat energy, and the process is complicated

The Chinese patent "A Method for Recovering Copper and Nickel from Electroplating Sludge" (CN201710900663.2) uses ammonia method and solvent extraction method to recover heavy metal copper and nickel in electroplating sludge. The process is relatively complicated, and Less than 90% copper recovery and less than 10% nickel recovery

The Chinese patent "A Method for Separately Recovering Copper, Nickel, and Zinc from Electroplating Sludge" (CN201710541111.7) directly obtained calcium sulfate, sponge copper, polyferric chloride, Zinc oxide, nickel sulfate ammonia and sodium sulfate industrial grade products, it is not possible to judge whether the electroplating sludge with high heavy metal content has a high recovery rate, and the process is complicated

The Chinese patent "A Method for Classifying and Recycling Iron, Copper, Nickel, and Chromium in Electroplating Sludge" (CN201710612163.9) provides a method for classifying and recycling iron, copper, nickel, and chromium in electroplating sludge, which can be realized from a technical point of view The recovery of iron, copper, nickel and chromium, but the method of ammonia immersion plus electrolysis to obtain nickel-copper alloy uses too much ammonia solution, the electrolysis time is long, and a large amount of acid is required to recover iron, aluminum and chromium, the process is relatively cumbersome, and the obtained The quality of chromium sulfate is not high