阅读说明：本技术 一种多孔氧化铝微球粉体的制备方法 (Preparation method of porous alumina microsphere powder ) 是由 徐强 杨辉 樊先平 熊林 吴海文 张正林 李冬云 于 2019-10-24 设计创作，主要内容包括：本发明涉及催化剂载体制备技术,旨在提供一种多孔氧化铝微球粉体的制备方法。包括：以除钠剂和去离子水配制成酸液,加入工业氢氧化铝,搅拌均匀后静置；过滤、清洗,获得低钠氢氧化铝粉；将低钠氢氧化铝粉与烧结助剂混合均匀后煅烧,冷却后得到多孔氧化铝微球粉体。本发明原料较少,工艺简单,无需复杂的设备；操作方便,耗时短、能耗低、投资少,成本低；可以制备出充分满足负载催化剂实际需要的多孔氧化铝微球粉体,并且产品制备成本低,具有推广意义。(The invention relates to a preparation technology of a catalyst carrier, and aims to provide a preparation method of porous alumina microsphere powder. The method comprises the following steps: preparing acid liquor by using a sodium removing agent and deionized water, adding industrial aluminum hydroxide, stirring uniformly and standing; filtering and cleaning to obtain low-sodium aluminum hydroxide powder; and uniformly mixing the low-sodium aluminum hydroxide powder with a sintering aid, calcining, and cooling to obtain the porous alumina microsphere powder. The invention has the advantages of less raw materials, simple process and no need of complex equipment; the operation is convenient, the time consumption is short, the energy consumption is low, the investment is less, and the cost is low; can prepare porous alumina microsphere powder which fully meets the actual needs of the supported catalyst, has low preparation cost and has popularization significance.)

1. A preparation method of porous alumina microsphere powder is characterized by comprising the following steps:

(1) preparing acid liquor by using a sodium removing agent and deionized water, adding industrial aluminum hydroxide, and uniformly stirring to obtain suspension; standing for 15 minutes, filtering the suspension, and washing the solid with deionized water to obtain low-sodium aluminum hydroxide powder;

the sodium removing agent is one or more of hypochlorous acid, oxalic acid or sulfuric acid, and the adding amount of the sodium removing agent accounts for 1-5% of the total weight of the suspension; the addition amount of the deionized water is equal to 100-200% of the weight of the industrial aluminum hydroxide; in the sodium-removed low-sodium aluminum hydroxide powder, Na₂The content of O is less than or equal to 0.12 percent;

(2) taking a sintering aid accounting for 0.5-1% of the mass of the low-sodium aluminum hydroxide powder, and uniformly mixing the low-sodium aluminum hydroxide powder and the sintering aid; then calcining the mixture for 1 to 3 hours at 1100 to 1300 ℃, and cooling the calcined mixture to obtain the porous alumina microsphere powder.

2. The method according to claim 1, wherein the step (1) is performed by washing with deionized water until the eluate has a pH of 8 or less.

3. The method according to claim 1, wherein the sintering aid in step (2) is at least one of ammonium fluoride and aluminum fluoride.

Technical Field

The invention belongs to a catalyst carrier preparation technology, and particularly relates to a preparation method of porous alumina microsphere powder.

Background

The spherical alumina has the excellent characteristics of corrosion resistance, high temperature resistance, high hardness, high strength, abrasion resistance, oxidation resistance, good insulativity, large surface area and the like, and is widely applied to high-tech fields such as metallurgy, chemical industry, electronics, national defense, aerospace, nuclear industry and the like. The spherical micro powder has good fluidity and sintering property, and is very beneficial to the tape casting of ceramic products; as a grinding and polishing material, the spherical alumina can avoid generating scratches; for injection-molded ceramics, the used spherical alumina can improve the fluidity of a melt, reduce the abrasion to a die, prolong the service life of the die and reduce the production cost; in the petrochemical industry, increasingly higher requirements are put on the pore size distribution and pore structure of an alumina carrier, and the pore size and the distribution of catalyst carrier particles formed by spherical alumina powder can be regulated and controlled by adjusting the particle size distribution.

The alumina catalyst carrier is low in price and easy to obtain, has the advantages of porosity, large specific surface area, high dispersibility, high thermal stability and the like, is the most widely used catalyst carrier and accounts for about 70% of industrial supported catalysts. The annual growth rate of the demand of the domestic and foreign markets for spherical alumina is continuously increased. The alumina carrier has various shapes such as spherical, columnar, bead-shaped, annular, cloverleaf-shaped, dentate spherical, hollow ring, multi-porous columnar and the like, and has quite good mechanical strength, surface structure, pore structure, specific surface area, solid acid-base property, grain size and the like required by different chemical reactions. Can be used for adsorbents, drying agents and various catalyst carriers, and is widely applied to the fields of petrochemical industry, hydrodesulfurization and low-temperature-change catalysts.

However, at present, the alumina carrier has more preparation raw materials, complex process and low success rate. In the CN108499552A patent, gibbsite, boehmite, fluoride, alkaline earth metal compound, silicon-containing compound, solid carbonaceous material, liquid organic compound, binder, etc. are prepared by molding, drying, and baking. The CN109201027A patent is made by molding, drying and roasting aluminum hydroxide with the grain size of 10 mu m or less and less than 100 mu m, aluminum hydroxide with the grain size of 100 mu m or less and less than 300 mu m, carbon-containing combustible with the grain size of 250 mu m or less and less than 800 mu m, a mixture of C15-C40 high-carbon alkane and high-carbon olefin, a mineralizer, an alkaline earth metal compound, a silicon-containing compound, a binder, water and the like. With the continuous expansion of the carrier application field, the preparation of the porous alumina carrier with low cost is particularly important.

Disclosure of Invention

The invention aims to solve the technical problem of overcoming the defects in the prior art and provides a preparation method of porous alumina microsphere powder.

In order to solve the technical problem, the solution of the invention is as follows:

the preparation method of the porous alumina microsphere powder comprises the following steps:

(1) preparing acid liquor by using a sodium removing agent and deionized water, adding industrial aluminum hydroxide, and uniformly stirring to obtain suspension; standing for 15 minutes, filtering the suspension, and washing the solid with deionized water to obtain low-sodium aluminum hydroxide powder;

the sodium removing agent is one or more of hypochlorous acid, oxalic acid or sulfuric acid, and the adding amount of the sodium removing agent accounts for 1-5% of the total weight of the suspension; the addition amount of the deionized water is equal to 100-200% of the weight of the industrial aluminum hydroxide; in the sodium-removed low-sodium aluminum hydroxide powder, Na₂The content of O is less than or equal to 0.12 percent;

(2) taking a sintering aid accounting for 0.5-1% of the mass of the low-sodium aluminum hydroxide powder, and uniformly mixing the low-sodium aluminum hydroxide powder and the sintering aid; then calcining the mixture for 1 to 3 hours at 1100 to 1300 ℃, and cooling the calcined mixture to obtain the porous alumina microsphere powder.

In the invention, the step (1) is washed by deionized water until the pH value of the eluent is less than or equal to 8.

In the present invention, the sintering aid in the step (2) is at least one of ammonium fluoride, aluminum fluoride, and the like.

Description of the inventive principles:

1. in the case of technical-grade aluminum hydroxide powders, a large number of lamellar structures are observed, despite the macroscopic spherical shape. The method can reduce the sodium content of the aluminum hydroxide by using the sodium removal process, improve the solid-liquid contact surface, strip impurities such as sodium salt and the like attached to the surface, and provide surface activated aluminum hydroxide particles for the subsequent sintering process.

2. The size of the industrial-grade aluminum hydroxide powder is about 50 mu m, and the method directly calcines aluminum hydroxide particles larger than 50 mu m after sodium removal at 1100-1300 ℃, so that more active sites are provided for the catalyst loading reaction, and the method is more favorable for adsorption; on the other hand, the lamellar structure is opened by utilizing thermal reaction, and the interface is activated by utilizing the auxiliary agent, so that phase transformation is generated, the lamellar structure is reduced and gelled, and larger pore microspheres are generated, thereby providing a channel for loading the catalyst. The product after calcination still keeps granular and can not be bonded, so the porous alumina microsphere powder can be obtained without grinding.

Compared with the prior art, the invention has the beneficial effects that:

1. the invention has the advantages of less raw materials, simple process and no need of complex equipment;

2. the method has the advantages of convenient operation, short time consumption, low energy consumption, less investment and low cost;

3. the invention can prepare the porous alumina microsphere powder which fully meets the actual requirement of the supported catalyst, and has low preparation cost and popularization significance.

Drawings

FIG. 1 is a photograph of porous alumina microsphere powder.

Detailed Description

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