Method for recycling valuable metal in waste circuit board

Abstract

The invention discloses a method for recycling valuable metal in a waste circuit board. The method includes the following steps that the waste circuit board is subject to smashing and reselection to prepare multi-metal powder; a dilute acid solution is added into the multi-metal powder, agitation leaching is carried out, filtering is carried out, and leaching slag I and leaching liquid I are obtained; an acid solution is added into the leaching slag I according to the liquid-solid mass ratio of the acid solution to the leaching slag I being 10-40:1, then an oxidizing agent is added, agitation leaching is carried out, filtering is carried out after leaching is finished, and leaching slag II and leaching liquid II are obtained; the leaching liquid II is subject to cyclone electrodeposition to obtain cathode copper and an after-electrolysis solution; alkali and a reducing agent are added into the leaching slag II, smelting is carried out under the condition that the temperature ranges from 400 DEG C to 600 DEG C, water leaching is carried out, filtering is carried out, and lead bullion containing precious metal and leaching liquid III are obtained; and the leaching liquid III is purified and is subject to evaporation and concentration to obtain a concentrated alkali solution and sodium stannate crystals. According to the method for recycling the valuable metal in the waste circuit board, the procedure is short, the efficiency is high, the cost is low, cleanness is achieved, and pollution is avoided.

Description

technical field [0001] The invention belongs to the technical field of secondary resource recovery, and in particular relates to a method for recovering valuable metals in waste circuit boards. Background technique [0002] In recent years, with the acceleration of the replacement of electronic products, my country has produced a large amount of electronic waste. Printed circuit boards are the core components of electronic products, and their scrap volume is also increasing. According to a report released by the United Nations Environment Program in 2010, my country produces more than 2.3 million tons of electronic waste every year, and the growth rate of discarded circuit boards is 14.4%. The circuit board contains about 30% metal materials (mainly copper, tin, iron, lead, aluminum, zinc and precious metals, etc.), 40% organic resin materials, and 30% glass materials as reinforced resin fibers. These metal elements Rich in variety, high in grade, and highly recyclable. T...

AI Technical Summary

Problems solved by technology

This method uses nitric acid leaching, the reagents are expensive, the requirements for equipment performance are high, the cost of tail gas treatment is high, and the copper with high value in the circuit board is not recovered.

[0006] The Chinese patent application with the patent number CN102747229A discloses a method for separating and recycling valuable metals in multi-metal enriched powders of waste circuit boards, using low-temperature alkaline smelting, water leaching, Na 2 S leaching realizes the efficient separation of amphoteric metals and copper, but the amphoteric metals are not selectively separated in the low-temperature alkaline smelting process, and the composition of the leachate is complex, which is not conducive to the subsequent separation process, and in an oxidizing atmosphere, dioxins, etc. may be produced. Toxic and harmful gas, high cost of environmental treatment

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