A method for synchronous leaching and separation of antimony, arsenic and alkali in arsenic-alkali slag

Abstract

A method for synchronous leaching and separation of antimony, arsenic and alkali in arsenic-alkali slag, comprising the following steps: adding water, glycerin and caustic soda to the crushed and ground arsenic-alkali slag or powdering the arsenic-alkali slag together with water, glycerin and caustic soda The milled slurry is sent to the leaching tank, the pH value is controlled, leaching and extraction are carried out, and solid-liquid separation is carried out to obtain silicon-aluminum mineral slag and alkali glycerin aqueous solution; After purification and precipitation treatment, arsenate crystals, lead slag, antimony oxide, phytate precipitates and glycerin soda ash aqueous solution are obtained; the obtained glycerin soda ash aqueous solution is subjected to nanofiltration or reverse osmosis membrane analysis to obtain nanofiltration concentrate and dialysate glycerin aqueous solution; The obtained dialysate glycerin aqueous solution is returned to soak the arsenic-alkali slag; the obtained nanofiltration concentrated solution is spray-dried to make soda ash or causticized with lime to produce caustic soda; the obtained antimony oxide is used for returning antimony to refining or processing antimony or refining antimony oxide and antimony acid Salt. The antimony, arsenic and alkali in the arsenic-alkali slag of the invention can be leached and separated synchronously, and the solvent can be recycled.

Description

technical field [0001] The invention relates to the technical field of comprehensive utilization of environmental protection waste resources, in particular to a resource utilization method for synchronous leaching and separation of antimony, arsenic and alkali in arsenic-alkali slag. Background technique [0002] Arsenic-alkali slag is a kind of arsenic-containing sodium arsenate, sodium antimonate, sodium carbonate and a certain amount of aluminosilicate minerals and compounds such as lead and bismuth produced during the antimony refining and arsenic removal process of antimony by fire method. Smelting waste residue, because sodium arsenate and sodium arsenite is highly toxic and easily soluble in water, can easily lead to environmental pollution incidents. It has been difficult to properly handle solid hazardous waste, which has restricted the healthy development of the antimony smelting industry to a certain extent. [0003] For the arsenic-alkali slag that is difficult t...

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Problems solved by technology

[0017] The above-mentioned fire treatment method requires harsh conditions for thermal reduction treatment, requiring a closed vacuum electric arc furnace, vacuuming with a vacuum pump, and forced vacuuming under high temperature conditions for 1 to 8 hours. The control requirements for this intermittent fire reduction treatment are very strict. , has high requirements for equipment and operation control, and may only be suitable for laboratory or small-batch metallurgical treatment, and the adaptability of large-scale industrial production is doubtful; it is also not suitable for processing arsenic-alkali slag containing a large amount of antimony, which uses a vacuum pump to continuously Under the condition of strong vacuuming at ≥800°C, the volatilization of antimony vapor will occur simultaneously with the sublimation of arsenic (arsenic sublimates at 615°C), and often only arsenic-antimony alloys are obtained; and it is difficult to deal with arsenic acid containing antimonate in large quantities Salt, using carbon as a reducing agent to smelt arsenic-alkali slag, the overall reducing ability is still extremely weak when the reducing temperature is lower than 800°C, and the reducing ability will be better when the temperature is above 900°C, and the higher the treatment temperature for hazardous waste, the less It’s just a problem of high energy consumption and higher equipment requirements, and the potential risk of accidents is even greater, and because the closed reduction furnace is used to rest the carbon powder to reduce the vacuum process, the crude antimony and lead still contains arsenic, and the reduction slag still contains arsenic. Not a small amount of arsenic (including soluble arsenate and insoluble arsenate) still only achieves the purpose of partial reduction and separation. Whether it is the return of crude antimony to refining or the return of reducing slag as arsenic removal agent, it has caused the cycle of arsenic

Even under strict control of the reaction conditions, the water leached slag separated from the reduced slag after water leaching still contains a certain amount of arsenic, which is still a hazardous solid waste that needs to be treated; the arsenic vapor or arsenic flue gas or elemental arsenic It is easy to be oxidized, especially in the process of forcibly pumping out from the high-temperature furnace with a vacuum pump to cooling. Even if a mixed atmosphere of inert gas and / or nitrogen and hydrogen and / or carbon monoxide is used, it is extremely difficult to recycle and reuse, which will easily lead to economical pollution. Poor performance or air pollution, and the vacuum pump relied on for vacuuming arsenic flue gas has extremely poor adaptability to metal particles or flue gas dust, making it difficult to ensure normal production and operation; or it is necessary to strictly control the equivalent ratio of sodium and phosphate The reaction conditions for the generation of trisodium phosphate are to simultaneously reduce the antimonate and arsenate in the arsenic-alkali slag to elemental antimony and elemental arsenic, but the production control habits of actual antimony smelting enterprises are difficult to guarantee the seemingly simple reaction conditions , and its processing energy consumption is high, and the potential pollution hazard is large, especially the arsenic-containing trisodium phosphate scum can easily flow into the agricultural fertilizer market quietly, resulting in uncontrollable spread of pollution

[0018] In summary, the separation of arsenic, antimony, and alkali in the existing treatment processes for various types of arsenic-alkali slag is relatively difficult, and problems such as environmental protection and economy are prominent.

The current domestic wet process is all focused on hot water leaching or oxidative water leaching, but there is no report on the research or practice of separating arsenic-alkali slag by leaching with aqueous glycerin