阅读说明：本技术 一种利用氯化铝生产勃姆石微钠米粉末的方法 (Method for producing boehmite micro-nano powder by using aluminum chloride ) 是由 王兆文 杨酉坚 郑晏辰 陶文举 石忠宁 高炳亮 胡宪伟 刘风国 于江玉 刘爱民 于 2020-07-15 设计创作，主要内容包括：一种利用氯化铝生产勃姆石微钠米粉末的方法,属于无机化学技术领域。该方法通过直接将AlCl<Sub>3</Sub>.6H<Sub>2</Sub>O晶体置于200～550℃中,进行水解,得到的无定型氧化铝中间产物采用常压水溶液溶出或加压高温水溶液溶出,溶出温度为70～300℃,得到的含有勃姆石晶体粉末的胶体溶液进行固液分离,分离后的勃姆石晶体粉末,用pH值<10的弱碱液洗涤后,在用清水洗涤、烘干,得到利用氯化铝生产的勃姆石微米粉末；分离后的胶体溶液进行聚沉,将得到的固相产品进行洗涤、烘干,得到利用氯化铝生产的勃姆石纳米粉末。该方法制备的勃姆石微钠米粉末,产品附加值较高,能量消耗低。(A method for producing boehmite micro-nano powder by utilizing aluminum chloride, belonging to the technical field of inorganic chemistry. The method is realized by directly mixing AlCl 3 .6H 2 Hydrolyzing the O crystal at 200-550 deg.C to obtain amorphous alumina intermediate, dissolving out with normal pressure water solution or pressurized high temperature water solution at 70-300 deg.C to obtain colloidal solution containing boehmite crystal powder, performing solid-liquid separation to obtain boehmite crystal powder, and adjusting pH to obtain boehmite crystal powder<10, washing with weak alkali liquor, washing with clear water, and drying to obtain boehmite micron powder produced by using aluminum chloride; and (3) coagulating the separated colloidal solution, washing and drying the obtained solid-phase product to obtain boehmite nano powder produced by using aluminum chloride. The boehmite micro-nano powder and product prepared by the methodThe added value is high, and the energy consumption is low.)

1. A method for producing boehmite micro-nano powder using aluminum chloride, comprising the steps of:

step 1: mixing AlCl₃.6H₂Placing the O crystal at 200-550 ℃ for hydrolysis to obtain an amorphous alumina intermediate product; al contained in amorphous alumina intermediate₂O₃In percentage by mass of>90 percent, and the mass percent of Cl is 0.8-8 percent;

step 2: dissolving an amorphous alumina intermediate product by adopting a normal-pressure aqueous solution or a pressurized high-temperature aqueous solution, wherein the dissolving temperature is 70-300 ℃, so as to obtain a colloidal solution containing boehmite crystal powder;

and step 3: carrying out solid-liquid separation on the colloidal solution containing the boehmite crystal powder to obtain boehmite crystal powder and the colloidal solution;

and 4, step 4:

(1) washing boehmite crystal powder with weak alkaline solution with the pH value of less than 10, washing with clear water, and drying to obtain boehmite micron powder produced by using aluminum chloride;

(2) and (3) coagulating the colloidal solution, washing and drying the obtained solid-phase product to obtain the boehmite nano powder produced by using aluminum chloride.

2. The method for producing boehmite micro-nano powder according to claim 1, wherein in step 1, the AlCl is added₃.6H₂The O crystal is a product produced by treating the fly ash by a hydrochloric acid method.

3. The method for producing boehmite micro-nano powder using aluminum chloride according to claim 1, characterized in that in the step 2, the boehmite is eluted in an aqueous solution at normal pressure at an elution temperature of 70 to 100 ℃ for 1 to 5 hours; dissolving out the mixture in a pressurized high-temperature water solution at the temperature of 100-300 ℃ for 30 min-2 h; wherein, the pressurized high-temperature aqueous solution is dissolved, and the pressure is determined according to the dissolution temperature of the aqueous solution.

4. The method for producing boehmite micro-nano powder using aluminum chloride according to claim 1, characterized in that in the step 2, stirring is accompanied during the dissolution.

5. The method for producing boehmite micro-nano powder using aluminum chloride according to claim 1, wherein in the step 2, the ratio of amorphous alumina intermediate product: water (63-125) g: 1000 mL.

6. The method for producing boehmite micro-nano powder according to claim 1, wherein in the step 3, the solid-liquid separation is one of centrifugal separation and pressure filtration.

7. The method for producing boehmite micro-nano powder according to claim 1, wherein in step 4(1), the weak alkaline solution is one or more of an aqueous solution of sodium hydroxide, an aqueous solution of potassium hydroxide, an aqueous solution of sodium carbide and an aqueous solution of potassium carbonate.

8. The method for producing boehmite micro-nano powder by using aluminum chloride according to claim 1, wherein in the step 4(2), the coagulation method is: adjusting pH to not less than 8, centrifuging, and adding electrolyte.

9. The method for producing boehmite micro-nano powder using aluminum chloride according to claim 1, characterized in that the coagulation method is: adding one or more of sodium hydroxide aqueous solution, potassium hydroxide aqueous solution, sodium carbide aqueous solution and potassium carbonate aqueous solution into the colloidal solution, and performing coagulation.

10. The method for producing boehmite micro-nano powder using aluminum chloride according to claim 1, wherein the boehmite micro-powder is produced with a particle size of 0.5 to 1.0 μm; the particle size of the prepared boehmite nano-powder is less than or equal to 100 nm.

Technical Field

The invention particularly relates to a method for producing boehmite micro-nano powder by using aluminum chloride, belonging to the technical field of inorganic chemistry.

Background

A large amount of fly ash solid waste is generated in China every year and needs to be treated, wherein the content of alumina in the high-alumina fly ash is higher than 40%, and the high-alumina fly ash has great recycling value. At present, a plurality of industrial methods for producing alumina by using fly ash exist, but a series of problems need to be solved, and the processes mainly comprise two main types of alkaline sintering and acid leaching; for the limestone sintering method in the alkaline sintering, although the process is simple and the alkali consumption is small, the temperature is high, the energy consumption is high, the dissolution rate of alumina is low, the limestone consumption is large, and the slag yield is also large; for the soda lime sintering method, the energy consumption is relatively lower than that of the limestone sintering method, but the production flow is long, the sintering process is unstable, and the dissolution rate of alumina is not high; therefore, there is a need for an improved technique for the alkaline process to achieve solid waste abatement treatment; for the acid leaching method, the flow is simple, the energy consumption is low, but the cost for removing impurities by the acid solution is too high, the equipment corrosion is serious, and the quality of the aluminum oxide is difficult to guarantee. Therefore, there are many problems in preparing alumina using fly ash.

And the alumina is prepared by adopting a fly ash acid method, so that the economic benefit is low. In the existing technology for preparing boehmite by hydrolyzing aluminum chloride hexahydrate, the hydrolysis is carried out in aqueous solution, and a precipitator, an organic acid reagent and the like are added for assistance, so that the cost is high, the subsequent treatment is complex, and waste liquid is generated and is unfavorable for the environment.

Disclosure of Invention

In view of the problems in the prior art, the present invention provides a method for producing boehmite micro-nano powder using aluminum chloride. The method utilizes an aluminum chloride product produced by high-alumina fly ash, aluminum chloride hexahydrate is hydrolyzed at low temperature to obtain an amorphous alumina intermediate product, the amorphous alumina intermediate product is dissolved out at high temperature under normal pressure or pressurization condition, so that the amorphous alumina intermediate product is subjected to lattice rearrangement crystallization at high temperature to form a boehmite (gamma-AlOOH) crystal structure, a colloidal solution containing boehmite crystal powder is obtained, the high-quality boehmite product is obtained through the procedures of precipitation, separation, washing, drying and the like, the granularity and the crystallization morphology of boehmite crystals can be controlled by controlling process conditions, can obtain 1 micron-sized and 100 nanometer-sized boehmite micro-nano-powder, has higher added value, can meet the requirements of industries such as high-grade molecular sieves, electronic ceramics, flame-retardant fillers, lithium batteries and the like, and has important significance for the development of the aluminum industry and the treatment of solid waste of fly ash in China. The method has the advantages of low energy consumption and high product quality.

The purpose of the invention is realized by adopting the following technical scheme:

a method for producing boehmite micro-nano powder using aluminum chloride, comprising the steps of:

step 1: mixing AlCl₃.6H₂Placing the O crystal at 200-550 ℃ for hydrolysis to obtain an amorphous alumina intermediate product; al contained in amorphous alumina intermediate₂O₃In percentage by mass of>90 percent, and the mass percent of Cl is 0.8-8 percent;

step 2: dissolving an amorphous alumina intermediate product by adopting a normal-pressure aqueous solution or a pressurized high-temperature aqueous solution, wherein the dissolving temperature is 70-300 ℃, so as to obtain a colloidal solution containing boehmite crystal powder;

and step 3: carrying out solid-liquid separation on the colloidal solution containing the boehmite crystal powder to obtain boehmite crystal powder and the colloidal solution;

and 4, step 4:

(1) washing boehmite crystal powder with weak alkaline solution with the pH value of less than 10, washing with clear water, and drying to obtain boehmite micron powder produced by using aluminum chloride;

(2) and (3) coagulating the colloidal solution, washing and drying the obtained solid-phase product to obtain the boehmite nano powder produced by using aluminum chloride.

In the step 1, the AlCl is adopted₃.6H₂The O crystal is a product produced by treating the fly ash by a hydrochloric acid method.

In the step 2, the mixture is dissolved out in a normal-pressure water solution, wherein the dissolving-out temperature is 70-100 ℃, and the dissolving-out time is 1-5 h; dissolving out the mixture in a pressurized high-temperature water solution at the temperature of 100-300 ℃ for 30 min-2 h. Wherein, the pressurized high-temperature aqueous solution is dissolved, and the pressure is determined according to the dissolution temperature of the aqueous solution.

In the step 2, in the process of dissolving out the aqueous solution at normal pressure, the boehmite crystal form is not completely generated and needs a long time. In pressure high temperature dissolution, the boehmite crystals are more complete at higher temperatures.

In the step 2, stirring may be carried out during the elution.

In the step 2, boehmite crystal powder has a boehmite crystal structure (γ -AlOOH) in the colloidal solution containing boehmite crystal powder.

In the step 2, according to the solid-liquid ratio, amorphous alumina intermediate products: water (63-125) g: 1000 mL.

In the step 3, the solid-liquid separation is performed by one of centrifugal separation and pressure filtration.

In the step 4(1), the weak alkali solution is one or more of a sodium hydroxide aqueous solution, a potassium hydroxide aqueous solution, a sodium carbide aqueous solution and a potassium carbonate aqueous solution.

In the step 4(2), the coagulation method comprises: adjusting pH to not less than 8, centrifuging, and adding electrolyte.

The coagulation method comprises the following steps: adding one or more of sodium hydroxide aqueous solution, potassium hydroxide aqueous solution, sodium carbide aqueous solution and potassium carbonate aqueous solution into the colloidal solution, and performing coagulation.

In the method for producing boehmite micro-nano powder by using aluminum chloride, the particle size of the prepared boehmite micro-powder is 0.5-1.0 mu m; the particle size of the prepared boehmite nano-powder is less than or equal to 100 nm.

The method for producing the boehmite micro-nano powder by using the aluminum chloride has the beneficial effects that:

by implementing the technical scheme of the invention, the aluminum chloride product produced by the fly ash can be effectively converted into the boehmite powder product with high added value, so that the method has great economic effect, and simultaneously utilizes solid wastes, thereby having great social benefit.

The method for producing the boehmite micro-nano powder by using the aluminum chloride has the following advantages:

1. in the process for producing aluminum chloride by using the hydrochloric acid method, the obtained aluminum chloride product contains high alkali metal (Li, Na, K) and alkaline earth metal (Mg, Ca) impurities. The intermediate product is dissolved out under high temperature and high pressure to generate boehmite crystals, and alkali metal and alkaline earth metal impurities in the boehmite crystals can be dissolved in water to remove the impurities.

2. By controlling the process conditions, 1 micron boehmite powder and 100 nanometer boehmite powder can be prepared, the product quality is improved, and the method has great economic effect.

3. AlCl of the invention₃.6H₂O crystals, which hydrolyze at high temperatures and which do not proceed in aqueous solution, by AlCl at high temperatures₃.6H₂The crystal water of the O crystal provides water molecules, so that hydrolysis is realized, and after hydrolysis, an amorphous alumina intermediate product is obtained, which provides a basis for the subsequent crystal lattice rearrangement and crystallization of the amorphous alumina intermediate product at high temperature to form a boehmite (gamma-AlOOH) crystal structure.

Drawings

Fig. 1 is an XRD pattern of boehmite prepared according to example 1 of the present invention.

Detailed Description

The present invention will be described in further detail with reference to examples.

AlCl adopted by the invention₃.6H₂The O crystal is a product produced by treating high-alumina fly ash by a hydrochloric acid method in a certain enterprise.