A fully enclosed process for treating hazardous waste-tungsten slag and recovering valuable metals

Abstract

The invention discloses a fully enclosed process for treating hazardous waste-tungsten slag and recovering valuable metals, comprising the following steps: step 1, neutralizing HCl; step 2, precipitating iron and manganese; step 3, separating solid and liquid; step 4 , recycle WO 3 Step 5, evaporation and concentration; Step 6, cooling and flaking; Step 7, drying and packaging; this invention, no waste water is discharged to the outside, realizes a fully enclosed process, and truly achieves zero discharge and zero pollution; Compared with the remaining liquid treatment process, the processes of sulfide removal of heavy metals, electrochemical treatment, activated carbon adsorption, electrodialysis concentration treatment and other processes are omitted, the process is greatly shortened, the cost is greatly reduced, and it is simpler and easier; not only greatly reduces the cost, but also The concentration of calcium chloride is also improved; the recovered CaCl2·2H2O can be directly sold as a chlorination agent, and its quality can fully meet the requirements of chlorination metallurgy, and has a broad demand market.

Description

technical field [0001] The invention relates to the technical fields of circular economy and non-ferrous metals, in particular to a fully enclosed process for treating hazardous waste-tungsten slag and recovering valuable metals. Background technique [0002] my country is a country with a large amount of tungsten resources, as well as the production and import and export of tungsten smelting products. Over the past decades, the residues after tungsten smelting (including scheelite slag and black tungsten slag) have accumulated up to millions of tons, and there are new tungsten slags every year. produce. In the past, the treatment method of tungsten slag was "taking the essence and discarding the dross". The secondary pollution caused by the tungsten slag is far more harmful to the environment than the tungsten smelting process itself. Therefore, in 2016, the State Council included tungsten slag in the "National Hazardous Waste List" for strict management, and tungsten slag ...

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Problems solved by technology

[0003] There is an existing method of decomposing tungsten slag with hydrochloric acid, further comprehensively recovering valuable tungsten and scandium, and recovering a large amount of iron and manganese, and obtaining enriched substances such as tin and tantalum, which provide raw materials for other industries and make non-ferrous metal resources It has been fully recycled. The main disadvantage of this process is that the waste water after extracting scandium raffinate plus soda to precipitate iron carbonate and manganese needs multi-stage process treatment to meet the requirements of effluent. The waste water treatment process of this process is too long and the treatment cost It is very high, and the treatment is not thorough, and the amount of wastewater discharged is large. Calculated by recycling 100 tons of tungsten slag per day, the wastewater that needs to be discharged into the river every day is as high as 350-400t / d; in addition, the quality of the recovered sodium chloride is not up to Requirements for industrial raw materials that must be further processed before they can be sold

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