Treatment method for molybdenum-containing acid wastewater generated in production of ammonium molybdate

Abstract

The invention discloses a treatment method for molybdenum-containing acid wastewater generated in production of ammonium molybdate, belonging to the technical field of wastewater treatment. The method comprises the following steps of: leading the molybdenum-containing acid wastewater to pass through an amino methylene phosphonic chelating resin column; collecting to obtain an effluent 1; sequentially adding ammonia water and slag into the effluent 1; naturally setting to obtain a supernatant; leading the supernatant to pass through the amino methylene phosphonic chelating resin column; collecting to obtain an effluent 2; evaporating and crystallizing the effluent 2; naturally cooling and filtering to obtain a filtering liquid and a filtering cake; drying the filtering cake to obtain ammonium nitrate; adding the filtering liquid into the effluent 2; and recycling the filtering liquid to realize treatment of the molybdenum-containing acid wastewater generated in production of the ammonium molybdate. According to the method, molybdenum and copper in the wastewater can be comprehensively recovered to obtain by-product ammonium nitrate, zero emission of the wastewater is realized, and the method has wide application prospect.

Description

technical field [0001] The invention relates to a treatment method for molybdenum-containing acidic wastewater produced in the production process of ammonium molybdate, belonging to the technical field of wastewater treatment. Background technique [0002] Ammonium molybdate is an important raw material for catalysts in the petrochemical industry and polymer synthesis industry, ceramic glazes and pigments, special analytical reagents and drugs, and the production of metal molybdenum wires and sheets. The traditional production process of ammonium molybdate generally adopts a series of processes such as molybdenum concentrate roasting, nitric acid leaching, ammonia leaching, purification and acid precipitation. During the nitric acid leaching process, a large amount of acidic wastewater (pH value < 1.5) will inevitably be produced, which contains many and complex metal ion components, especially the average molybdenum content is 1.2g / L. For a long time, due to the lack of...

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Problems solved by technology

Among them, the precipitation method has high requirements on equipment, complicated process, relatively high cost and the chemicals used (such as sodium sulfide, etc.) are generally dangerous, which is not suitable for industrial applications; the extraction method has the problems of pollution and long treatment period; The exchange method mainly uses anion exchange resins such as D314. Before the acidic wastewater passes through the column, it is necessary to adjust the pH value above 2.5 with alkali to ensure that molybdenum exists in the form of anions.

However, when the pH value is neutralized to 2.5~3.0, 70% of the molybdenum in the wastewater is co-precipitated in the environmental residue, which has a great impact on the production cost and comprehensive recovery rate of molybdenum; The treatment is feasible, and the waste liquid can be concentrated and treated, but the investment and operation costs are high, the concentration ratio is limited, and the concentrated liquid still needs final treatment, etc.

In summary, these methods have failed to reach the technical and economic indicators of industrialized treatment due to single means, low treatment efficiency, and high treatment costs.

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