阅读说明：本技术 一种高比表面积的氧化锌的生产方法 (Production method of zinc oxide with high specific surface area ) 是由 林德 陈晓 钟湘兵 龙文建 于 2021-09-03 设计创作，主要内容包括：本发明公开了一种高比表面积的氧化锌的生产方法,将纯碱直接加入硫酸锌溶液中,经过浸出、净化、中和、水洗、闪蒸煅烧步骤,使硫酸锌溶液与纯碱直接接触而发生化学反应,并将加纯碱时间严格控制在8h,反应速度快,不易生成大颗粒；同时本发明的中和反应温度控制在42℃,反应温度低,物料反应快,生成的物料较细。本发明具有粒径小、分散性好、比表面积高以及制备方法简单的优点。(The invention discloses a production method of zinc oxide with high specific surface area, which comprises the steps of directly adding sodium carbonate into a zinc sulfate solution, carrying out leaching, purification, neutralization, washing, flash evaporation and calcination, directly contacting the zinc sulfate solution with the sodium carbonate to carry out chemical reaction, strictly controlling the time for adding the sodium carbonate to be 8 hours, and having high reaction speed and difficult generation of large particles; meanwhile, the neutralization reaction temperature of the invention is controlled at 42 ℃, the reaction temperature is low, the reaction of the materials is fast, and the generated materials are fine. The invention has the advantages of small particle size, good dispersibility, high specific surface area and simple preparation method.)

1. A production method of zinc oxide with high specific surface area comprises the following steps:

the method comprises the following steps: leaching: preparing 800kg of pure water, 200kg of concentrated sulfuric acid and 300kg of zinc hypoxide, adding water into a leaching reaction tank, adding concentrated sulfuric acid, uniformly adding the zinc hypoxide twice when the temperature of liquid rises to 65 ℃, adding 150kg of zinc hypoxide each time, uniformly stirring, reacting for 1.5 hours, discharging and filtering when the zinc sulfate solution in the leaching reaction tank reaches 110 g/l;

step two: primary purification: pumping the zinc sulfate solution filtered in the step one into a purification tank to purifyHeating the liquid in the melting tank to 85 ℃, adding heavy calcium carbonate and sulfuric acid to adjust the pH value of the solution to 5.0, then adding potassium permanganate with the concentration of 0.1mol/l while stirring, and detecting Mn by adopting an atomic absorption method²⁺Content up to Mn²⁺Content (wt.)<1mg/l, then, filtering iron and manganese residues in the solution in the purification tank, wherein the filtrate is the primary purified zinc sulfate solution;

secondary purification: pumping the primary purified zinc sulfate solution into a displacement tank, heating to 52 ℃, adding concentrated sulfuric acid to adjust the pH value of the solution, adding metallic zinc powder when the pH value is 3.5, stopping adding when the pH value reaches 5.4, stirring for 2 hours after the addition is finished, and filtering out precipitated heavy metal ions to prepare a pure zinc sulfate solution;

step three: neutralizing: pumping the purified zinc sulfate solution formed by secondary purification in the step two into a neutralization reaction tank, keeping the temperature at 42 ℃, adding sodium carbonate into the neutralization reaction tank by adopting a blanking machine, controlling the frequency of the blanking machine to be 4Hz, stirring for 6h, and when Zn is formed²⁺Content (wt.)<When the concentration of the zinc carbonate is 1.5g/l, heating the solution to 85 ℃, stirring for 1.5h to generate a mixed material of basic zinc carbonate and sodium sulfate, and separating the mixed material by using a filter press;

step four: washing with water: washing the separated basic zinc carbonate solution with water to remove SO in the mixed material₄ ^2-Thoroughly washing, and performing pressure filtration on the thoroughly washed materials through a pressure filter to obtain a basic zinc carbonate filter cake with the water content of 35%, wherein the standard of thorough washing is as follows: sampling, filtering, titrating by using BaCl2 solution, and completely washing without white precipitate;

step five: flash evaporation and calcination: and (3) feeding the basic zinc carbonate filter cake into a dryer, dispersing and drying to form powdery basic zinc carbonate, feeding the powdery basic zinc carbonate into a dynamic calcining furnace, heating by hot air at 700 ℃, decomposing the basic zinc carbonate into zinc oxide, and trapping by a trap to obtain the finished product of the nano zinc oxide with high specific surface area.

2. The method for producing zinc oxide with high specific surface area according to claim 1, wherein: in the second step, Mn is detected by adopting an atomic absorption method every 5min for one-time purification²⁺Content (wt.)。

3. The method for producing zinc oxide with high specific surface area according to claim 1, wherein: in the third step, the stirring adopts a double-layer flat paddle, the elevation angle of the paddle is 17 degrees, and the frequency of the stirrer is 18 Hz.

4. The method for producing zinc oxide with high specific surface area according to claim 1, wherein: the time for adding soda ash in the third step is 8 h.

Technical Field

The invention relates to the field of zinc oxide processing, in particular to a production method of zinc oxide with high specific surface area.

Background

Zinc oxide is a commonly used chemical additive, and is widely applied to the manufacture of products such as plastics, silicate products, synthetic rubber, lubricating oil, paint, coating, ointment, adhesive, food, batteries, flame retardant and the like. The nano zinc oxide is a multifunctional novel inorganic material, and the particle size of the nano zinc oxide is about 1-100 nanometers. Due to the fine grain, the surface electronic structure and the crystal structure of the crystal grain are changed, and the characteristics of surface effect, volume effect, quantum size effect, macroscopic tunnel effect, high transparency, high dispersibility and the like which are not possessed by macroscopic objects are generated. In recent years, the zinc oxide has been found to show a plurality of special functions in the aspects of catalysis, optics, magnetism, mechanics and the like, so that the zinc oxide has important application values in a plurality of fields of ceramics, chemical engineering, electronics, optics, biology, medicine and the like, and has specificity and application which can not be compared with common zinc oxide. The nano zinc oxide can be used for ultraviolet light shielding materials, antibacterial agents, fluorescent materials, photocatalytic materials and the like in the fields of textiles, coatings and the like.

At present, there are many methods for preparing zinc oxide nano-materials, such as indirect methods and direct methods such as vapor deposition, sol-gel method, precipitation method, combustion method, hydrothermal method and template method. The obtained zinc oxide nano-rod material has a relatively large diameter ratio, a particle size of 0.1 to several millimeters, a relatively small specific surface area, non-uniform size, poor dispersibility and poor adsorption effect on dyes.

Disclosure of Invention

The invention aims to provide a production method of zinc oxide with high specific surface area, which solves the problems of large particle size, poor dispersibility and small length-diameter ratio of nano zinc oxide, thereby improving the specific surface area and chemical activity of the nano zinc oxide.

The technical problem solved by the invention can be realized by adopting the following technical scheme:

a production method of zinc oxide with high specific surface area comprises the following steps:

the method comprises the following steps: leaching: preparing 800kg of pure water, 200kg of concentrated sulfuric acid and 300kg of zinc hypoxide, adding water into a leaching reaction tank, adding concentrated sulfuric acid, uniformly adding the zinc hypoxide twice when the temperature of liquid rises to 65 ℃, adding 150kg of zinc hypoxide each time, uniformly stirring, reacting for 1.5 hours, discharging and filtering when the zinc sulfate solution in the leaching reaction tank reaches 110 g/l;

step two: primary purification: pumping the zinc sulfate solution filtered in the step one into a purification tank, heating the liquid in the purification tank to 85 ℃, adding heavy calcium carbonate and sulfuric acid to adjust the pH value of the solution to 5.0, then adding potassium permanganate with the concentration of 0.1mol/l while stirring, and detecting Mn by adopting an atomic absorption method²⁺Content up to Mn²⁺Content (wt.)<1mg/l, then, filtering iron and manganese residues in the solution in the purification tank, wherein the filtrate is the primary purified zinc sulfate solution;

secondary purification: pumping the primary purified zinc sulfate solution into a displacement tank, heating to 52 ℃, adding concentrated sulfuric acid to adjust the pH value of the solution, adding metallic zinc powder when the pH value is 3.5, stopping adding when the pH value reaches 5.4, stirring for 2 hours after the addition is finished, and filtering out precipitated heavy metal ions to prepare a pure zinc sulfate solution;

step three: neutralizing: pumping the purified zinc sulfate solution formed by secondary purification in the step two into a neutralization reaction tank, keeping the temperature at 42 ℃, adding sodium carbonate into the neutralization reaction tank by adopting a blanking machine, controlling the frequency of the blanking machine to be 4Hz, stirring for 6h, and when Zn is formed²⁺Content (wt.)<When the concentration of the zinc carbonate is 1.5g/l, heating the solution to 85 ℃, stirring for 1.5h to generate a mixed material of basic zinc carbonate and sodium sulfate, and separating the mixed material by using a filter press;

step four: washing with water: washing the separated basic zinc carbonate solution with water to remove SO in the mixed material₄ ²Thoroughly washing, and press-filtering the thoroughly washed material by a filter press to obtain a basic zinc carbonate filter cake with the water content of 35%, wherein the standard for thoroughly washing is as follows: sampling, filtering, titrating by using BaCl2 solution, and completely washing without white precipitate;

step five: flash evaporation and calcination: and (3) feeding the basic zinc carbonate filter cake into a dryer, dispersing and drying to form powdery basic zinc carbonate, feeding the powdery basic zinc carbonate into a dynamic calcining furnace, heating by hot air at 700 ℃, decomposing the basic zinc carbonate into zinc oxide, and trapping by a trap to obtain the finished product of the nano zinc oxide with high specific surface area.

Preferably, in the second step, the Mn is detected by adopting an atomic absorption method every 5min for one-time purification²⁺And (4) content.

Preferably, the stirring in the third step adopts a double-layer flat paddle, the elevation angle of the paddle is 17 degrees, and the frequency of the stirrer is 18 Hz.

Preferably, the soda ash adding time in the third step is 8 hours.

According to the invention, the soda ash is directly added into the zinc sulfate solution, so that the zinc sulfate solution is directly contacted with the soda ash to generate a chemical reaction, the soda ash adding time is strictly controlled at 8h, the reaction speed is high, and large particles are not easy to generate; meanwhile, the neutralization reaction temperature of the invention is controlled at 42 ℃, the reaction temperature is low, the material reaction is fast, the generated material is fine, and the product has the advantages of small particle size, good dispersibility and high specific surface area.

Detailed Description

The present invention will be described in further detail with reference to examples, but the embodiments of the present invention are not limited thereto.

A production method of zinc oxide with high specific surface area comprises the following steps in sequence:

(1) leaching out

Preparing 800kg of pure water, 200kg of concentrated sulfuric acid and 300kg of zinc hypoxide, adding all the water into a leaching reaction tank, slowly adding the concentrated sulfuric acid, uniformly adding the zinc hypoxide twice when the temperature is raised to 65 ℃, namely adding 150kg of zinc hypoxide each time, reacting for 1.5 hours after uniformly stirring, discharging and filtering when the zinc sulfate solution in the leaching reaction tank reaches 110 g/l.

In the process, the zinc hypoxide powder and the sulfuric acid are fully reacted to generate zinc sulfate which is remained in the solution, and impurities which do not participate in the reaction can be filtered and recovered to recover downstream residual elements.

The equation of the leaching reaction is ZnO + H₂SO₄＝ZnSO₄+H₂O

The reaction formula of the reaction process of other main metal oxides and sulfuric acid in the raw materials is as follows:

PbO+H₂SO₄＝PbSO₄↓+H₂O

FeO+H₂SO₄＝FeSO₄+H₂O

Fe₂O₃+3H₂SO₄＝Fe₂(SO₄)₃+3H₂O

CuO+H₂SO₄＝CuSO₄+H₂O

CdO+H₂SO₄＝CdSO₄+H₂O。

(2) purification

One-time purification

Pumping the zinc sulfate solution filtered in the step (1) into a purification tank, heating the liquid in the purification tank to 85 ℃, and adding heavy calcium carbonateAnd sulfuric acid, adjusting the pH value of the solution to 5.0, and uniformly stirring. Then potassium permanganate with the concentration of 0.1mol/1 is added while stirring, and Mn is detected by an atomic absorption method every 5min²⁺Content up to Mn²⁺Content (wt.)<1mg/1, then filtering iron and manganese residues in the solution in the purifying tank by a filter press, and obtaining the primary purified zinc sulfate solution after filtering.

Second purification

Pumping the primary purified zinc sulfate solution into a displacement tank, heating to 52 ℃, adding concentrated sulfuric acid to adjust the pH value of the solution, adding metallic zinc powder when the pH value is 3.5, and stopping adding when the pH value is 5.4. Stirring for 2h after the addition is finished, and then filtering out heavy metal ions such as copper, cadmium and the like which are precipitated to prepare a pure zinc sulfate solution.

The displacement equation is:

Zn+Meⁿ⁺+SO₄ ^2-→Me↓+ZnSO₄wherein Me is a harmful metal impurity.

(3) Neutralization

Pumping the purified zinc sulfate solution formed by secondary purification into a neutralization reaction tank, keeping the temperature at 42 ℃, adding soda ash into the neutralization reaction tank by adopting a blanking machine, controlling the frequency of the blanking machine to be 4HZ, controlling the soda ash adding time to be 8h, adopting a double-layer flat paddle for stirring, controlling the paddle elevation angle to be 17 degrees and the frequency of a stirrer to be 18Hz, stirring for 6 hours, sampling and testing every 5min, and when Zn is detected²⁺Content (wt.)<And when the concentration is 1.5g/1, heating the solution to 85 ℃, stirring for 15 hours to generate a mixed material of basic zinc carbonate and sodium sulfate, and separating the mixed material by adopting a vertical filter press to form a basic zinc carbonate solution and a sodium sulfate finished product.

The reaction formula of the process is as follows:

3ZnSO₄+3Na₂CO₃+3H₂O→ZnCO₃·2Zn(OH)₂·H₂O↓+3+2CO₂↑

and (4) feeding the separated sodium sulfate solution into a triple-effect evaporator to generate a sodium sulfate product, packaging and warehousing.

(4) Washing with water

Washing the separated basic zinc carbonate solution with water, and mixing the obtained solutionsSO in the material₄ ²Thoroughly washing, and press-filtering the thoroughly washed material by a filter press to obtain a basic zinc carbonate filter cake with the water content of 35%, wherein the standard for thoroughly washing is as follows: sampling, filtering, and purifying with BaCL₂The solution is titrated, and no white precipitate is obtained, namely the solution is washed thoroughly.

(5) Flash calcination

And (2) feeding the basic zinc carbonate filter cake into a Sde dryer, dispersing and drying to form powdery basic zinc carbonate, feeding the powdery basic zinc carbonate into a dynamic calcining furnace, heating the basic zinc carbonate by hot air at 700 ℃ to rapidly decompose the basic zinc carbonate into zinc oxide, and trapping the decomposed zinc oxide by a trap and feeding the zinc oxide into a storage bin to obtain the finished product of the nano zinc oxide with high specific surface area.

The reaction during calcination is:

ZnCO₃·2Zn(OH)₂·H₂O→3ZnO+3H₂O+CO₂↑。

tests show that the content of the high-activity nano zinc oxide prepared by the preparation method can reach more than 95 percent, and the specific surface area is not less than 100 square meters per gram, so that the high-activity nano zinc oxide is high in activity and easy to disperse, is extremely suitable for production of tires, conveyer belts, shoes, ceramics, coatings, EVA foaming and the like, and has a good effect.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the technical scope of the present invention, so that any minor modifications, equivalent changes and modifications made to the above embodiments according to the technical spirit of the present invention still belong to the protection scope of the present invention.