Method for preparing high-quality sodium pyroantimonate by ultrasonic strengthening

Abstract

The present application relates to the field of nonferrous metallurgy, and provides a method for preparing high-quality sodium pyroantimonate by ultrasonic strengthening, comprising the following steps: preparing a mixed solution with the concentration of sodium hydroxide being 200-400 g / L and the concentration of an additive being 10-40 g / L; the additive is potassium hydroxide and / or glycerol; adding antimony oxide into the mixed solution at a proportion of 150-250 kg / m 3 , and heating and performing ultrasonic treatment to obtain a mixed slurry; adding hydrogen peroxide into the mixed slurry, continuing to react for 10-120 min after the hydrogen peroxide is completely added, then performing liquid-solid separation to obtain a solid product; drying the solid product after washing to obtain a sodium pyroantimonate product. The essence of the present application is that the oxidation diffusion process is strengthened by using ultrasonic waves and an additive, and the high-quality sodium pyroantimonate product is prepared by the combined action. The sodium pyroantimonate product prepared by the method has the advantages of good quality, low consumption of oxidizing agent, stable technical indexes, etc.

Description

[0001] This invention is a divisional application based on the application filed on October 31, 2023, with application number 202311432545.5, entitled "A method for preparing high-quality sodium pyroantimonate by ultrasonic enhancement". Technical Field

[0002] This invention relates to heavy metal metallurgical processes in the field of non-ferrous metallurgy, and in particular to a hydrometallurgical method for preparing high-quality sodium pyroantimonate using ultrasonic enhancement. Background Technology

[0003] Antimony is a brittle, silvery-white metal with poor electrical and thermal conductivity. It is mainly used in alloys, military industry, flame retardants, and glass manufacturing. The main mineral raw materials for antimony smelting include stibnite, antimony-gold ore, and brittle pyrolusite. Antimony flue dust is a byproduct of heavy metal smelting and an important secondary raw material for antimony recovery.

[0004] The main products of antimony include metallic antimony ingots, antimony white, and sodium pyroantimonate. Sodium pyroantimonate is mainly used as a clarifying and decolorizing agent for industrial glass. Glass products made from it have the advantages of high transparency, no discoloration under light, and low toxicity. It is widely used in television picture tubes, high-grade glass, enamel industry, and semiconductor industry. It accounts for a high proportion of antimony products and is a fine chemical product with broad economic prospects.

[0005] Based on their chemical properties, the raw materials used in the production of sodium pyroantimonate can be divided into two categories: one is high-purity antimony products, represented by industrial pure antimony and industrial antimony white; the other is high-impurity antimony mineral raw materials, represented by stibnite and antimony ash. Existing methods for preparing sodium pyroantimonate mainly include the sodium nitrate oxidation method, the chlorination method, the oxidation reflux method, the potassium salt method, and the air oxidation method. Among these, only the sodium nitrate oxidation method belongs to pyrometallurgical processes, while the others belong to hydrometallurgical processes.

[0006] The sodium nitrate oxidation method is a traditional method for preparing sodium antimonate by oxidizing metallic antimony or antimony trioxide under high-temperature alkaline conditions. First, metallic antimony is mixed with an excess of sodium nitrate and calcined at high temperature in a rotary kiln to oxidize the antimony to its pentavalent state. Finally, the sodium nitrate is washed away with water, and the product is dried and pulverized to produce sodium antimonate pyrophosphate. While the sodium nitrate oxidation method has advantages such as simple process, short flow, and easy operation, it cannot effectively remove impurities during production, and the waste gas generated during production cannot be completely eliminated, resulting in low-quality products. Therefore, it has been phased out.

[0007] The chlorination process involves oxidizing and leaching antimony-containing raw materials with chlorine gas in a hydrochloric acid system. The leachate is then neutralized and hydrolyzed with sodium hydroxide to produce sodium pyroantimonate precipitate. After washing and drying, the sodium pyroantimonate product is obtained. The chlorination process has the advantages of low raw material requirements and good product quality, but it also has disadvantages such as a long process flow, severe equipment corrosion, and large wastewater volume.

[0008] The oxidation reflux method is a one-step process for preparing sodium antimonate by directly oxidizing antimony trioxide with hydrogen peroxide in a sodium hydroxide solution. In this method, antimony trioxide, sodium hydroxide, and water are added to a reactor in a specific ratio. After the slurry is heated to a certain temperature, hydrogen peroxide solution is added dropwise to initiate the oxidation reflux reaction. The reaction product is washed with water and then dried to obtain sodium antimonate. The oxidation reflux method has advantages such as simple process, short flow, and easy operation, but it also has disadvantages such as high Sb(III) content in the product, large hydrogen peroxide consumption, and poor product quality. Current research focuses on solving problems related to raw material adaptability, process impurity removal capabilities, and reducing Sb(III) content.

[0009] The potassium salt method is based on the property that potassium pyroantimonate has high solubility in aqueous solution, while sodium pyroantimonate is almost insoluble in water. First, Sb(III) is oxidized to Sb(V) in a potassium hydroxide system using hydrogen peroxide and dissolved. After liquid-solid separation, the solution reacts with sodium hydroxide to produce the sodium pyroantimonate product. The main advantage of the potassium salt method is the high quality of the sodium pyroantimonate product. The disadvantage is the significant loss of potassium salts in the intermediate products, resulting in excessively high production costs.

[0010] The air oxidation method uses stibnite concentrate or brittle lead-stigmine concentrate as raw material, leaching with sodium sulfide and sodium hydroxide. Antimony is introduced into the solution as sodium thioantimonite. Air is bubbled in to oxidize the sodium thioantimonite to sodium pyroantimonite precipitate. After washing and drying, sodium pyroantimonite product is obtained. The oxidized solution is neutralized, impurity removed, concentrated, and crystallized to recover sodium thiosulfate as a byproduct. The air oxidation method directly produces sodium pyroantimonite from sulfide ore, significantly reducing costs, but it suffers from drawbacks such as a long process flow and poor product quality. Some researchers have proposed using pressure oxidation to shorten the air oxidation time, achieving better results.

[0011] Based on the advantages and disadvantages of the above methods, and addressing the shortcomings of the currently widely used oxidation reflux method, a method for preparing high-quality sodium pyroantimonate by ultrasonic enhancement is proposed. Summary of the Invention

[0012] To overcome the shortcomings of the traditional oxidation reflux method, this invention provides a hydrometallurgical method for preparing high-quality sodium pyroantimonate by using ultrasound and additives to jointly enhance oxidation diffusion control, resulting in high-quality products at low cost.

[0013] To achieve the above objectives, the technical solution adopted in this invention is as follows: First, a mixed solution of sodium hydroxide and additives of the required concentration is prepared. Second, antimony oxide of the required mass is directly added and the temperature is raised. Then, ultrasound is initiated and the required frequency and power density are controlled. Finally, hydrogen peroxide is added to the mixed slurry at the required rate. After the hydrogen peroxide is added, the reaction continues for a certain period of time, followed by liquid-solid separation. The solid product is washed and dried, and the mother liquor is recycled. The essence of this invention is that it uses both ultrasound and additives to enhance the control of oxidation diffusion, achieving the goal of ultrasound-enhanced preparation of high-quality sodium antimonate pyroantimonate products.

[0014] The specific process and parameters are as follows: First, prepare a mixed solution with sodium hydroxide concentration of 200-400 g / L and additive concentration of 10-40 g / L. Then, add antimony oxide at a rate of 150-250 kg per cubic meter. Raise the temperature to 60-90℃, then start the ultrasonic treatment and control the ultrasonic frequency at 40-80 kHz and the power density at 0.5-1.2 W / cm³. 2 Finally, hydrogen peroxide is added to the mixed slurry at a rate of 15.0-25.0 kg / min. After all the hydrogen peroxide has been added, the reaction continues for 10-120 min. The liquid and solid are separated by vacuum filtration. The solid product is dried to obtain sodium pyroantimonate, and the mother liquor is recycled.

[0015] The main chemical reactions that occur are as follows: Sb2O3+2NaOH+2H2O2+3H2O=2NaSb(OH)6 (1) The hydrogen peroxide solution of this invention has a H2O2 content of greater than 27.5% by mass.

[0016] The antimony content in the antimony oxide of this invention is greater than 80.0% by weight.

[0017] The additive described in this invention is one or both of potassium hydroxide and glycerol.

[0018] Compared with the traditional method for preparing sodium pyroantimonate from antimony oxide, this invention has the following advantages: 1. The use of additives can effectively improve the solubility of antimony oxide in sodium hydroxide solution, transforming the original solid-solid reaction into a liquid-solid reaction, thus significantly improving the subsequent oxidation effect; 2. The use of ultrasonic enhancement improves the diffusion effect, promotes the oxidation process, and reduces the trivalent antimony content in the sodium pyroantimonate product to less than 0.3%; 3. The use of ultrasonic enhancement can effectively reduce the oxidation temperature requirements and oxidant consumption; 4. This invention has the advantages of stable process technical indicators, low labor intensity, and low production cost. Attached Figure Description

[0019] Figure 1 : Schematic diagram of the process flow of this invention. Detailed Implementation

[0020] Example 1: The antimony oxide contains 83.30% antimony by weight, the sodium hydroxide contains 96.5% NaOH by weight, and the hydrogen peroxide contains 28.0% H2O2 by weight. First, a mixed solution with sodium hydroxide concentrations of 300 g / L and potassium hydroxide concentrations of 28 g / L is prepared. Then, antimony oxide is added at a rate of 180 kg per cubic meter, and the temperature is raised to 82°C. Ultrasonic testing is then initiated, with the ultrasonic frequency controlled at 40 kHz and the power density at 0.6 W / cm³. 2 Finally, hydrogen peroxide was added to the mixed slurry at a rate of 20.0 kg / min. After all the hydrogen peroxide was added, the reaction continued for 60 min. The liquid and solid were separated by vacuum filtration. The solid product was dried to obtain sodium pyroantimonate. The content of trivalent antimony in the sodium pyroantimonate product was 0.08%. The mother liquor was recycled.

[0021] Example 2: The antimony oxide contains 83.30% Sb₂O₃ by weight, the sodium hydroxide contains 96.5% NaOH by weight, and the hydrogen peroxide contains 28.0% H₂O₂ by weight. First, a mixed solution with sodium hydroxide and glycerol concentrations of 300 g / L and 30 g / L, respectively, is prepared. Then, antimony oxide is added at a rate of 190 kg per cubic meter, and the temperature is raised to 82°C. Ultrasonic testing is then initiated, with the ultrasonic frequency controlled at 40 kHz and the power density at 0.6 W / cm². 2 Finally, hydrogen peroxide was added to the mixed slurry at a rate of 20.0 kg / min. After all the hydrogen peroxide was added, the reaction continued for 60 min. The liquid and solid were separated by vacuum filtration. The solid product was dried to obtain sodium pyroantimonate. The content of trivalent antimony in the sodium pyroantimonate product was 0.06%. The mother liquor was recycled.

Claims

1. A method for preparing high-quality sodium pyroantimonate using ultrasonic enhancement, characterized in that, Includes the following steps: (1) Prepare a mixed solution with sodium hydroxide and additive concentrations of 200-400 g / L and 10-40 g / L, respectively; the additive is potassium hydroxide and / or glycerol; (2) Add 150-250 kg / m³ to the mixed solution 3 Antimony oxide was added in a certain proportion and heated to undergo ultrasonic treatment to obtain a mixed slurry; (3) Add hydrogen peroxide to the mixture slurry, and continue the reaction for 10-120 minutes after all the hydrogen peroxide has been added. Then, perform liquid-solid separation to obtain a solid product. (4) The solid product is washed and dried to obtain sodium pyroantimonate product.

2. The method for preparing high-quality sodium pyroantimonate by ultrasonic enhancement according to claim 1, characterized in that, In step (2), the heating is to raise the temperature to 60-90°C.

3. The method for preparing high-quality sodium pyroantimonate by ultrasonic enhancement according to claim 1, characterized in that, The ultrasonic treatment in step (2) has a frequency of 40-80 kHz and a power density of 0.5-1.2 W / cm². 2 .

4. The method for preparing high-quality sodium pyroantimonate by ultrasonic enhancement according to claim 1, characterized in that, The hydrogen peroxide is added at a rate of 15.0-25.0 kg / min in step (3).

5. The method for preparing high-quality sodium antimonate pyroantimonate by ultrasonic enhancement according to any one of claims 1-4, characterized in that, The hydrogen peroxide contains more than 27.5% H2O2 by mass. The antimony oxide contains more than 80.0% antimony by mass.

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