CN-121974385-A - Method for deeply removing impurities in acidic primary metastannic acid product by combining neutralization and ultrasonic

Abstract

The invention relates to a method for deeply removing impurities in an acidic primary product of metastannic acid by combining neutralization and ultrasonic waves, belonging to the technical field of purification of the acidic primary product of metastannic acid. Aiming at the problems of high acidity and serious impurity wrapping of a primary product of metastannic acid prepared by a nitric acid method, the invention adds ammonium bicarbonate solution into the primary product of metastannic acid prepared by the nitric acid method for neutralization reaction, carries out solid-liquid separation to obtain a neutralized metastannic acid product, adds the neutralized metastannic acid product into washing water for ultrasonic sectional strengthening washing, carries out solid-liquid separation and dries to obtain a qualified metastannic acid product with the pH value of 5-7, and sequentially comprises ultrasonic pre-dispersion (preliminary crushing of metastannic acid particle aggregates) and ultrasonic strengthening stripping (deep removal of adsorbed impurity ions). The invention efficiently removes residual acid by neutralization of ammonium bicarbonate, strengthens mass transfer and particle dispersion by utilizing ultrasonic cavitation effect, realizes deep removal of impurity ions, and can reach the standard by only one-time washing.

Inventors

• LI SHIQIONGCHUN
• ZHANG LIBO
• ZHANG QIAN
• XIA HONGYING
• WANG DONGBIN
• WANG TIAN

Assignees

• 昆明理工大学

Dates

Publication Date

20260505

Application Date

20260210

Claims (8)

1. 1. A method for deeply removing impurities in an acidic primary metastannic acid product by combining neutralization and ultrasonic is characterized by comprising the following specific steps: (1) Adding ammonium bicarbonate solution into a primary product of metastannic acid prepared by a nitric acid method for neutralization reaction, and carrying out solid-liquid separation to obtain a neutralized metastannic acid product; (2) And adding the neutralized metastannic acid product into washing water for ultrasonic sectional strengthening washing, carrying out solid-liquid separation, and drying to obtain a qualified metastannic acid product with the pH value of 5-7, wherein the ultrasonic sectional strengthening washing sequentially comprises ultrasonic pre-dispersion and ultrasonic strengthening stripping.
2. 2. The method for deeply removing impurities in an acidic metastannic acid primary product by combining neutralization and ultrasonic treatment according to claim 1, wherein the pH value of the metastannic acid primary product in the step (1) is 1-2, and the acid content is 2.6-4.0 mmol/g.
3. 3. The method for deeply removing impurities in an acidic primary product of metastannic acid by combining neutralization and ultrasonic waves according to claim 1, wherein the concentration of the ammonium bicarbonate solution in the step (1) is 1.0-2.0 mol/L, and the addition amount of the ammonium bicarbonate is 0.5-1.0 times of the stoichiometric amount required by theoretical total acid in the primary product of metastannic acid.
4. 4. The method for deeply removing impurities in acidic metastannic acid primary products by combining neutralization and ultrasonic treatment according to claim 1, wherein the neutralization reaction temperature in the step (1) is 20-30 ℃ and the reaction time is 5-10 min.
5. 5. The method for deeply removing impurities in an acidic metastannic acid primary product by combining neutralization and ultrasonic waves according to claim 1, wherein the solid-to-liquid ratio g/mL of the neutralized metastannic acid product to the washing water in the step (2) is 1:2-4 based on the dry matrix of the neutralized metastannic acid product.
6. 6. The method for deeply removing impurities in an acidic metastannic acid primary product by combining neutralization and ultrasonic according to claim 1, wherein the ultrasonic power density of ultrasonic pre-dispersion in the step (2) is 2-5W/mL, the frequency is 20-28 kHz, the temperature is 20-30 ℃ and the time is 4-8 min.
7. 7. The method for deeply removing impurities in an acidic metastannic acid primary product by combining neutralization and ultrasonic according to claim 6, wherein the ultrasonic power density of ultrasonic enhanced stripping in the step (2) is 6-9W/mL, the frequency is 30-40 kHz, the temperature is 20-30 ℃ and the time is 3-5 min.
8. 8. The method for deeply removing impurities in acidic metastannic acid primary products by combining neutralization and ultrasonic treatment according to claim 1, wherein the drying temperature in the step (2) is 70-90 ℃ and the time is 5-7 h.

Description

Method for deeply removing impurities in acidic primary metastannic acid product by combining neutralization and ultrasonic Technical Field The invention relates to a method for deeply removing impurities in an acidic primary product of metastannic acid by combining neutralization and ultrasonic waves, belonging to the technical field of purification of the acidic primary product of metastannic acid. Background The metastannic acid (H 2SnO3) is used as a tin deep processing chemical product, has wide application, is a key precursor for preparing tin dioxide (SnO 2), and is also an important material in the front-edge fields of gas sensors, lithium ion batteries, aerospace, new energy sources and the like. At present, the nitric acid method is mainly adopted in industry to produce the metastannic acid, namely, tin reacts with concentrated nitric acid at normal pressure. The reaction is severe, and a large amount of nitric acid and nitrate impurities are adsorbed in the product along with the generation of a large amount of nitrogen oxides, so that a compact acid wrapping structure is formed, and the pH value of the product is usually 1-2. The acidic impurities not only corrode equipment, but also have stronger specific adsorption effect on the surfaces of nitrate ions (NO 3-) and the metastannic acid colloid, so that stable acid shells are formed, and the quality of the metastannic acid (tin dioxide) product is seriously reduced. The traditional acid removal method such as ammonium bicarbonate neutralization-water washing (HNO 3＋NH4HCO3=NH4NO3＋H2O＋CO2 ∈) is difficult to destroy a special compact package structure of the metastannic acid by the nitric acid method, a large amount of new impurity ions such as ammonium radical (NH 4+) and the like are introduced into an excessive neutralizing agent to cause secondary pollution, and the reaction can be accelerated at high temperature, but the metastannic acid colloid is easy to gelatinize or peptize, so that the packaged impurities are plugged again, are difficult to diffuse to a liquid phase, and the packaged internal acidic impurities cannot be effectively removed. The sulfuric acid process disclosed in patent document CN108285170a adopts ammonium bicarbonate for neutralization and washing, but the sulfuric acid and tin react gently, the generated metastannic acid has a loose structure, the sulfate ion combination adsorbed on the surface is weaker, and the sulfate ion is easy to remove by conventional washing, so the process cannot be directly applied to a nitric acid system. Disclosure of Invention Aiming at the initial product of the metastannic acid prepared by the nitric acid method and having strong adsorption and inclusion acidic impurities, the invention provides a method for deeply removing the impurities in the initial product of the acidic metastannic acid by combining neutralization and ultrasonic treatment, residual acid is efficiently removed by neutralization of ammonium bicarbonate (free acid on the surface is quickly neutralized, peptization risks caused by high-temperature decomposition and local pH sudden rise are avoided), mass transfer and particle dispersion are enhanced by utilizing ultrasonic cavitation effect (agglomeration and inclusion layer are broken by low-intensity ultrasonic waves and internal impurities are exposed), deep removal of impurity ions is realized (micro-jet flow and shock waves are generated by high-intensity ultrasonic waves through cavitation effect, and impurity stripping and desorption are enhanced). A method for deeply removing impurities in an acidic primary metastannic acid product by combining neutralization and ultrasonic comprises the following specific steps: (1) Adding ammonium bicarbonate solution into a primary product of metastannic acid prepared by a nitric acid method for neutralization reaction, and carrying out solid-liquid separation to obtain a neutralized metastannic acid product; (2) And adding the neutralized metastannic acid product into washing water for ultrasonic sectional strengthening washing, carrying out solid-liquid separation, and drying to obtain a qualified metastannic acid product with the pH value of 5-7, wherein the ultrasonic sectional strengthening washing sequentially comprises ultrasonic pre-dispersion and ultrasonic strengthening stripping. Preferably, the pH value of the initial product of the metastannic acid in the step (1) is 1-2, and the acid content is 2.6-4.0 mmol/g. Preferably, the concentration of the ammonium bicarbonate solution in the step (1) is 1.0-2.0 mol/L, and the addition amount of the ammonium bicarbonate is 0.5-1.0 times of the stoichiometric amount required for theoretically neutralizing the total acid in the primary product of the metastannic acid. Preferably, the neutralization reaction temperature in the step (1) is 20-30 ℃, and the reaction time is 5-10 min. Preferably, the solid-to-liquid ratio g of the neutralized metastannic acid product to the wa