Method for preparing zinc sulfate solution de-fluorination agent

Abstract

The invention discloses a method for preparing a zinc sulfate solution de-fluorination agent, which comprises the following steps: 99% glacial acetic acid reacts with lime slurry to produce a calcium acetate solution, the calcium acetate solution is evaporated and concentrated to obtain calcium acetate monohydrate, and the calcium acetate monohydrate is dried to obtain anhydrous calcium acetate; industrial sulphuric acid reacts with lime slurry to produce calcium sulfate dehydrate, and the calcium sulfate dehydrate is dried to obtain calcium sulfate; 60-80% of anhydrous calcium acetate, 15-30% of calcium sulfate and 5-10% of industrial polyalumi rlillm sulfate are mixed by mass percent, then crushed and packaged, so that the zinc sulfate solution de-fluorination agent is obtained. The de-fluorination agent prepared through the method is simple in production process, calcium of the de-fluorination agent exists in the soluble matter form, the de-fluorination efficiency is high, the high capability is realized, and the cost is low.

Description

technical field [0001] The invention relates to the field of nonferrous metal smelting, in particular to a method for preparing a zinc sulfate solution defluorination agent. Background technique [0002] In the wet zinc smelting process, when the fluoride ion impurities in the zinc sulfate electrolytic solution are high, the cathode plate will be severely corroded, making it difficult to peel off the zinc sheet. To remove fluoride ions in the solution, there are calcium salt precipitation method, goethite co-precipitation method, special activated alumina adsorption method, silica gel adsorption method, anion resin exchange method, organic polymer adsorption method, rare earth adsorption method, etc. [0003] The calcium salt precipitation method uses the reaction of calcium ions and fluoride ions to form calcium fluoride precipitates with low solubility and good stability. This method has the advantages of simple operation and stable defluorination products, but its disadva...

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Problems solved by technology

[0003] The calcium salt precipitation method uses the reaction of calcium ions and fluoride ions to form calcium fluoride precipitates with low solubility and good stability. This method has the advantages of simple operation and stable defluorination products, but its disadvantage is that the defluorination effect fluctuates greatly , the amount of reagent used is large, and when it is used in industrial production, the defluorination depth is low, especially when dealing with solutions containing less than 150 mg / L of fluorine, the defluorination efficiency is greatly reduced, and it is not suitable to treat solutions with low fluorine content

[0004] Goethite co-precipitation method, using the solution to precipitate iron, when goethite precipitates are formed, part of the fluoride ions replace and replace the hydroxide ions in goethite molecules, and together with goethite, form co-precipitation, This method has the advantages of low production cost and stable product, and is suitable for treating solutions with high iron content and low fluorine content. iron content solution

[0005] The special activated alumina adsorption method utilizes the reaction performance and adsorption performance of alumina at the same time. Polymeric ions are adsorbed by unreacted alumina, so that part of the fluoride ions in the solution are transferred to the surface or gap of alumina, and the purpose of defluorination of the solution is initially achieved; this method has the advantages of fast reaction speed and high defluorination efficiency. The disadvantage is that the special activated alumina has a small adsorption capacity and consumes a large amount, resulting in high production costs. Therefore, it cannot be popularized and applied on a large scale

[0006] Silica gel adsorption method: its principle is similar to that of special activated alumina adsorption method. At the same time, the reaction performance and adsorption performance of silicon oxide are used, and silicon oxide reacts with fluoride ions in the solution to generate hexafluorosilicon polymer ions, which reduces the fluoride ions in the solution. At the same time, silicon hexafluoride polymer ions are adsorbed by unreacted silicon oxide, so that part of the fluorine ions in the solution are transferred to the surface or gap of silicon oxide, and the purpose of defluorination of the solution is initially achieved; this method has lower production costs advantages, but its slow reaction speed and small adsorption capacity lead to low defluorination efficiency, and it is difficult to achieve 50% defluorination. Therefore, the degree of industrialization and application is smaller than that of special activated alumina adsorption method

[0007] Anion resin exchange method, this method is to use the specific functional group structure on the strong basic resin or modified strong basic resin to have the characteristic of preferential adsorption of fluoride ion than sulfate ion, when the solution flows through the resin, the fluorine in the solution The ions are adsorbed on the resin to achieve the purpose of removing fluoride ions. This method has the advantages of low production cost and large processing capacity. Affected by the chloride ions in the solution, when the chloride ions in the solution exist, they will also be adsorbed by the resin, resulting in a further reduction in the defluorination efficiency

[0008] The organic polymer adsorption method uses the specific functional group structure on the organic polymer to complex the fluorine ion. Under the action of the stirring facility, the fluoride ion in the solution is complexed or substituted into the organic polymer to achieve the removal of fluorine. The purpose of this method is high defluorination efficiency, large processing capacity, and small metal loss. There is a negative impact

[0009] The principle of rare earth adsorption method is similar to that of special activated alumina adsorption method. At the same time, the reaction performance and adsorption performance of rare earth are used. The activity of fluoride ions, while fluoride precipitation and hexafluoropolymerized alkali metal ions are adsorbed by unreacted rare earths, so that part of the fluoride ions in the solution is transferred to the surface or gap of rare earths, and the purpose of defluorination of the solution is initially achieved; this method has The advantages of fast defluorination speed and high defluorination efficiency, but the disadvantages are that rare earths are expensive and the cost of defluorination is high. At present, they have not been popularized and applied in industrialization

[0010] In theory, fluoride ions can react with calcium ions to produce calcium fluoride with good stability and small solubility. When the fluorine is lower than 150mg / L solution, the defluorination efficiency is greatly reduced

Through preliminary analysis, the main reason for the gap between practice and theory is that the reaction reagents are greatly disturbed by zinc ions and sulfate ions in the solution, and the movement of zinc ions and sulfate ions in the solution changes the movement law of calcium ions, resulting in calcium ions low activity

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