Method for enriching and recycling cadmium from lead smelting system

Abstract

The invention belongs to a non-ferrous metal metallurgy industry and particularly relates to a method for enriching and recycling cadmium from a lead smelting system. The method comprises the following steps: matching a lead concentrate with auxiliary materials and returned low-cadmium smoke and dust, and adding desulfurization smelting lea of a bottom blowing furnace; circularly enriching the cadmium in electric dust-collection smoke and dust in a form of cadmium sulfate; when the cadmium content of the electric dust-collection smoke and dust is 5%-28%, leaching by using water or dilute sulfuric acid to separate the cadmium; displacing a leaching solution by using zinc powder to produce cadmium sponge and further producing rough cadmium and fine cadmium; and taking a solution obtained by displacing the cadmium as a raw material for producing nano zinc oxide, zinc sulfate monohydrate and zinc sulfate heptahydrate to recycle zinc. The lead is enriched in leached dreg in a leaching process so that the lead can be conveniently returned back to a lead system to be smelted and recycled. According to the method, a bottom blowing smelting technology is adopted; when the lead is smelted, the cadmium in the raw material is efficiently enriched and converted into a water-soluble cadmium salt; a technological process is shortened and conditions for directly enriching, separating and recycling the lead and the cadmium are provided; the dispersion of the lead when the cadmium is recycled by a wet method is avoided and the production cost is reduced.

Description

technical field [0001] The invention belongs to the nonferrous metal smelting industry, in particular to a method for enriching and recovering cadmium from a lead smelting system. Background technique [0002] At present, cadmium metal is mainly recovered comprehensively from the zinc smelting system. The main recovery process is: the zinc sulfide concentrate is roasted, so that zinc and cadmium enter the calcine in the form of oxide and sulfate, and when the calcine is acid leached, the zinc and Cadmium enters the solution in the form of sulfate. Harmful metals in the solution need to be removed before zinc electrowinning. The main method for removing cadmium is to add zinc powder for replacement, and produce copper and cadmium replacement slag; then use dilute sulfuric acid or zinc electrowinning solution for oxidative leaching Copper cadmium replacement slag, the output copper cadmium slag leaching solution is replaced twice with zinc powder to remove cadmium, the first s...

AI Technical Summary

Problems solved by technology

It can be seen that when recovering cadmium from the lead smelting system, the traditional process is long, the cadmium is seriously dispersed, the enrichment and separation are difficult, the heavy metal pollution is large, a large number of chemical reagents are used, the production cost is high, and the metal recovery rate is low.

[0004] At present, bottom-blowing furnace oxidation-blast furnace (reduction furnace) reduction lead smelting process is widely used in China. Most of the cadmium-containing materials produced by high-temperature smelting are rich in lead and zinc. Some companies sell this part of cadmium-containing materials to zinc smelters to recover cadmium. , when this kind of high-cadmium-containing lead-zinc soot is sold, neither cadmium nor zinc is priced, only the price of lead is calculated, which makes this method of recycling cadmium poor in economic benefits, economically unreasonable, and loses a certain amount of lead metal , zinc smelters also bear the risk of heavy metal lead pollution

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