A comprehensive recovery process for arsenic, copper and bismuth in copper-bismuth slag

Abstract

The present invention is a comprehensive recovery process of arsenic, copper and bismuth in copper-bismuth slag, taking the copper-bismuth slag produced by sulfidation and step-by-step precipitation of copper-bismuth-containing acidic waste liquid produced by copper smelting flue gas acid production as the research object, and the copper-bismuth slag Oxygen pressure leaching is carried out in a sulfuric acid system, and then copper bismuth slag is added to the leaching slurry, the copper sulfate in the slurry replaces the arsenic sulfide in the copper bismuth slag, and the copper bismuth slag reduces pentavalent arsenic to trivalent arsenic, and is filtered The trivalent arsenic solution and slag phase can be obtained; the trivalent arsenic solution can be evaporated, concentrated and cooled to crystallize to obtain white arsenic products. Sodium chlorate and hydrochloric acid are added to the slag phase under normal pressure to leaching copper and bismuth. The leaching solution is first added with a dilute alkali solution for hydrolysis reaction to generate bismuth oxychloride, which is separated from solid and liquid, and solid alkali is added to the filtrate to make the solution neutral. Recycled copper. The leached slag is returned to the lead smelting system to recover lead, and the hydrolyzed solution is returned to the copper-bismuth leaching process. The invention has the advantages of short technological process, economical applicability, no pollution, low energy consumption, and realizes efficient separation and comprehensive recovery of arsenic, copper and bismuth.

Description

technical field [0001] The invention belongs to the technical field of resource and waste recycling, in particular to a comprehensive recovery process for arsenic, copper and bismuth in copper-bismuth slag. Background technique [0002] A large amount of sulfur-containing flue gas produced by the pyro-smelting of copper is mainly used for the preparation of sulfuric acid. The large amount of polluted acid wastewater produced after the flue gas washing in the acid production process contains about 10-30 mg / L of metal rhenium, 600-800 mg / L of copper, and 500 of bismuth. ~1000 mg / L, arsenic 13~20g / L, copper, bismuth and arsenic are first precipitated by controlled potential sulfide precipitation, and then rhenium precipitation is carried out. enrichment. The process of precipitating copper, bismuth and arsenic produces a large amount of copper and bismuth slag. At present, copper is recovered by returning to the furnace for smelting. However, arsenic and bismuth have been circ...

AI Technical Summary

Problems solved by technology

The copper, bismuth, and arsenic precipitation process produces a large amount of copper, bismuth and arsenic slag. At present, copper is recovered by remelting, and arsenic and bismuth have been circulating in the system in a closed circuit, which not only increases the equipment load, but also increases the concentration of arsenic and bismuth in the copper electrolyte. , which seriously affects the quality of cathode copper

In addition, when copper-bismuth slag is treated by pyrotechnics alone, the smelting slag contains high bismuth, the separation of arsenic and bismuth is not complete, the direct recovery rate of bismuth refining is low, and the environmental pollution is large

In the wet treatment process, the copper sulfate replacement method, alkali leaching method, oxygen pressure leaching method and ferric sulfate method can all achieve the removal of arsenic and the enrichment of copper and bismuth, but the copper sulfate replacement method consumes a lot of copper powder and costs high

The alkaline leaching method consumes a lot of alkali and is difficult to recycle. The alkaline leaching solution needs to go through an oxidation-reduction process to prepare arsenic products with low environmental risks.

The ferric sulfate method is complex and costly, and the iron in the prepared arsenic trioxide tends to exceed the standard, making it difficult to meet the purity requirements

Using oxygen pressure leaching-sulfur dioxide / sodium sulfite reduction process to treat copper bismuth slag can obtain arsenic trioxide with better quality, but the whole process returns more materials, and the ratio of arsenic entering the final product is relatively low