A method for separating arsenic and selenium from copper anode slime alkaline leaching solution

Abstract

The invention discloses a method for separating arsenic and selenium from copper anode slime alkaline leach liquor. The method comprises the following steps: 1) oxidation, namely adding an oxidizing agent or introducing oxidizing gas into the copper anode slime alkaline leach liquor, so that oxidized copper anode slime alkaline leach liquor is obtained; 2) arsenic precipitation, namely adding a calcium salt into the oxidized copper anode slime alkaline leach liquor, stirring the obtained mixture so as to produce a precipitate, and carrying out filtration and separation on the precipitate so as to obtain a calcium arsenate precipitate and arsenic post-precipitation liquid; and 3) selenium precipitation, namely adding a barium salt into the arsenic post-precipitation liquid obtained in the step 2), stirring the obtained mixture so as to produce a precipitate, carrying out filtration and separation on the precipitate so as to obtain a barium selenate precipitate and selenium post-precipitation liquid, and carrying out evaporative crystallization on the selenium post-precipitation liquid so as to recycle alkali, or directly returning to a leaching process. The method disclosed by the invention is short in technological process, less in equipment and simple in operation, and can be used for realizing the separation and enrichment of arsenic and selenium, the precipitation rate of arsenic is higher than 96%, and the precipitation rate of selenium is higher than 99%; by virtue of carrying out evaporative crystallization on a solution for recycling or directly returning the solution to a leaching process, the recovery of alkali is realized.

Description

technical field [0001] The invention relates to a method for separating arsenic and selenium, in particular to a method for separating arsenic and selenium from copper anode slime alkaline leaching solution. Background technique [0002] Copper anode slime is a type of intermediate product produced in the copper electrolytic refining process that contains valence elements such as copper, lead, antimony, selenium, tellurium and noble metals, as well as harmful element arsenic. After the copper anode slime is treated by alkaline metallurgical processes such as soda roasting leaching, alkaline smelting leaching, and pressurized alkaline leaching, arsenic and selenium are separated from heavy and precious metals and enriched in the alkaline leaching solution. [0003] At present, the separation methods of arsenic in alkaline solution mainly include crystallization precipitation method and acidification precipitation method. Among them, the crystallization precipitation method us...

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Problems solved by technology

[0003] At present, the separation methods of arsenic in alkaline solution mainly include crystallization precipitation method and acidification precipitation method. Among them, the crystallization precipitation method uses the solubility difference of arsenate at different temperatures to separate arsenic, and can only deal with high-concentration arsenic-containing solutions. The precipitation method is to acidify the solution and then oxidize it, and then add reagents such as iron salts to form insoluble arsenate. The process is long and the reaction process requires a lot of acid

The separation method of selenium in alkaline solution is mainly the reduction method, that is, using sulfur dioxide, sodium sulfite and other reducing agents to reduce selenium to elemental selenium in a strong acid system and recover it. The main problem is that the acid consumption and waste water are large, and there is low concentration of sulfur dioxide pollution.

At the same time, the above-mentioned separation methods for arsenic and selenium are generally only aimed at a single alkaline solution containing arsenic or selenium, without considering the separation and enrichment of arsenic and selenium and the recovery of alkali

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