阅读说明：本技术 一种耐磨高纯氧化铝研磨球的制备方法 (Preparation method of wear-resistant high-purity alumina grinding ball ) 是由 卢胜波 殷剑龙 刘瑾 李刚 王程民 王修慧 于 2020-07-30 设计创作，主要内容包括：本发明涉一种耐磨高纯氧化铝研磨球的制备方法：将醇盐水解法制备的高纯拟薄水铝石,通过一次低温焙烧、气流磨处理、二次高温焙烧制备高纯氧化铝粉体；然后研磨,干燥得到单分散纯相α-氧化铝超细粉体；采用高纯拟薄水铝石制备高纯铝溶胶,喷雾造粒制备球形氧化铝前驱体,焙烧得到球形氧化铝种子；进行一次滚动成型和二次等静压成型制备氧化铝球坯体；高温烧结、自磨抛光得到氧化铝研磨球；最后通过迭代方式操作,制备的氧化铝研磨球纯度不断提高升级,最终得到纯度4N以上的耐磨高纯氧化铝研磨球。(The invention relates to a preparation method of wear-resistant high-purity alumina grinding balls, which comprises the following steps: preparing high-purity alumina powder from the high-purity pseudoboehmite prepared by the alkoxide hydrolysis method through primary low-temperature roasting, airflow milling treatment and secondary high-temperature roasting; then grinding and drying to obtain monodisperse pure-phase alpha-alumina superfine powder; preparing high-purity alumina sol by using high-purity pseudo-boehmite, preparing a spherical alumina precursor by spray granulation, and roasting to obtain spherical alumina seeds; carrying out primary rolling forming and secondary isostatic pressing forming to prepare an alumina ball blank; sintering at high temperature, and autogenously grinding and polishing to obtain alumina grinding balls; and finally, operating in an iterative mode, and continuously improving and upgrading the purity of the prepared alumina grinding ball to finally obtain the wear-resistant high-purity alumina grinding ball with the purity of more than 4N.)

1. A preparation process of wear-resistant high-purity alumina grinding balls is characterized by comprising the following steps: the method comprises the following steps:

firstly, roasting the high-purity pseudo-thin diasphore prepared by an alkoxide hydrolysis method at the low temperature of 1100 ℃ for one time to prepare transition alumina, fluidizing by an airflow mill, and roasting at the high temperature of 1150 ℃ and 1300 ℃ for two times to obtain high-purity alumina;

secondly, adding 95 aluminum oxide grinding balls (the content of aluminum oxide is 95%) and the aluminum oxide powder into a grinding machine according to the mass ratio of 10-2:1, adding high-purity water and a dispersing agent, and carrying out wet grinding for 2-24 hours to obtain slurry;

thirdly, the slurry is sieved by a 100-mesh 325-mesh nylon sieve and then dried to obtain monodisperse pure-phase alpha-alumina superfine powder;

fourthly, preparing high-purity alumina sol from the high-purity pseudo-boehmite, then preparing a spherical alumina precursor by spray granulation, and then roasting at the temperature of 600-1150 ℃ to obtain spherical alumina seeds with the size of 40-100 mu m;

fifthly, rolling and forming are carried out, and firstly, small ball seeds are added; then continuously adding the prepared powder, spraying an adhesive, and continuously rolling and growing up to obtain an alumina sphere blank with the particle size of 1-20 mm;

sixthly, introducing the alumina ball blank into liquid rubber for dipping, taking out, airing and curing, then putting into cold isostatic pressing equipment for secondary pressure forming, and degumming at the temperature of 250-450 ℃;

seventhly, placing the mixture into a high-temperature kiln, sintering the mixture for 1 to 6 hours at 1450 and 1600 ℃, and then self-grinding and polishing the mixture to obtain a finished product;

and eighthly, using the prepared alumina grinding medium, and continuously improving and upgrading the purity of the prepared alumina through an iterative mode operation to finally obtain the wear-resistant high-purity alumina grinding ball with the purity of more than 4N.

2. The preparation process of the wear-resistant high-purity alumina grinding ball according to claim 1, which is characterized in that: the first step of preparing high purity pseudoboehmite by alkoxide hydrolysis method, the first low temperature sintering prepared transition alumina is gamma phase, theta phase or mixed phase, the first low temperature sintering temperature is 1050 ℃ for any crystal form except alpha phase, and the second high temperature sintering temperature is 1150-1300 ℃.

3. The preparation process of the wear-resistant high-purity alumina grinding ball according to claim 1, which is characterized in that: the first step is fluidized treatment by the jet mill, the adopted jet mill is one or more of a flat jet mill with a ceramic lining or a fluidized bed jet mill, the pressure is 0.5-1.3Mpa, and the apparent density of the obtained powder is less than or equal to 0.3g/cm³(ii) a The drying mode is one or two of spray drying, microwave drying or freeze drying.

4. The preparation process of the wear-resistant high-purity alumina grinding ball according to claim 1, which is characterized in that: the resistance of the high-purity water added in the grinding in the second step is more than 10 megohms, and the weight ratio of the high-purity water to the 5N high-purity alumina powder is 5: 1-2:1.

5. The preparation process of the wear-resistant high-purity alumina grinding ball according to claim 1, which is characterized in that: the second step is that the dispersant is: one or two of organic dispersing agents such as ammonium polyacrylate, OP-10, SPAN-80, polyoxyethylene ether, stearamide, oleic acid and the like are compounded, and the using amount is 0.01-0.5 percent of the weight of the high-purity water.

6. The preparation process of the wear-resistant high-purity alumina grinding ball according to claim 1, which is characterized in that: fourthly, the high-purity pseudo-boehmite is utilized to prepare the high-purity aluminum sol by self, the proportion of the high-purity pseudo-boehmite in the deionized water is 10-30%, then one or two or more of sulfuric acid, nitric acid, acetic acid and oxalic acid are added, and the mixture is stirred for 0.5-24h to form gel under the condition of 80-90 ℃.

7. The preparation process of the wear-resistant high-purity alumina grinding ball according to claim 1, which is characterized in that: the adhesive sprayed in the rolling balling process in the fifth step is organic adhesive such as PVA, hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl methyl cellulose, gelatin and the like, one or more of the organic adhesive is a mixture of the organic adhesive and high-purity aluminum sol, and the organic adhesive is: high-purity aluminum sol: 10-20% of deionized water: 0.5-10%: 70-85%; the rotating speed of the rolling ball is 20-100 r/min.

8. The preparation process of the wear-resistant high-purity alumina grinding ball according to claim 1, which is characterized in that: sixthly, performing secondary pressure molding by using cold isostatic pressing equipment, wherein the pressure is 80-120 Mpa; the liquid rubber is polyurethane rubber, butadiene rubber, styrene butadiene rubber, nitrile butadiene rubber and the like, and the viscosity is 20-50 Pa.s.

9. The preparation process of the wear-resistant high-purity alumina grinding ball according to claim 1, which is characterized in that: seventhly, sintering at 1450-1600 ℃ at high temperature for 1-6 hours; the self-grinding polishing is carried out by adding sintered alumina grinding balls into a self-grinding machine lined with polyurethane.

10. The preparation process of the wear-resistant high-purity alumina grinding ball according to claim 1, which is characterized in that: and the eighth step is to use the newly prepared grinding balls with higher purity to replace the grinding balls with lower purity of the previous generation for a new production operation until the product purity is stably over 4N.

Technical Field

The invention belongs to the technical field of preparation of high-purity alumina ceramics, and particularly relates to a preparation method of a wear-resistant high-purity alumina grinding ball.

Background

The invention relates to a grinding medium for grinding powder materials in a ball mill, in particular to a grinding medium for high-purity superfine alumina powder. Five different types of grinding media are currently commercially available, including: steel balls, glass balls, zirconia balls, alumina balls, composite zirconia-alumina balls. The key factor in selecting which materials to use for the grinding media is the materials used to make them. Each grinding media has its particular use. However, each grinding media has a problem that it is not suitable for some uses. Because the grinding medium itself is worn away during the grinding process, the object to be ground is contaminated to some extent. Such as: the steel ball is used for grinding alumina, iron impurities can be introduced, the zirconium ball is used for grinding alumina, and for introducing zirconium element, low-purity aluminum balls are used for grinding high-purity alumina, and impurities such as Na, Mg, Si and the like contained in the aluminum balls can be introduced, so that the purity of the high-purity alumina is reduced, the purity requirement of product preparation cannot be met, and the application of the high-purity alumina in the application field is influenced. If the high-purity alumina medium with the same material as the high-purity alumina powder is used, even if the grinding medium is introduced into the high-purity alumina powder due to abrasion, the purity of the product is not influenced. Meanwhile, with the gradually known superiority of the performance of the nano material, the high-purity superfine alumina powder is widely applied to the field of new materials such as semiconductor ceramics, transparent ceramics, lithium batteries and the like. Therefore, the preparation of the wear-resistant high-purity alumina grinding medium is a simple, quick and labor-saving way for preparing high-purity superfine alumina powder.

The alumina ball as grinding medium has the general technological processes of compounding, ball milling, pelletizing, rolling to form and sintering. However, the purity of the alumina balls prepared in the found patents cannot meet the market demand, the purity is low, the wear resistance is poor, and the purity requirement of the current customers cannot be met, for example, the invention contents of Chinese patents CN102491735A, CN104150882A and the like cannot solve the problems of product purity and strength, so that the grinding media cannot be applied to the application field of high-purity superfine alumina.

The invention adopts alkoxide hydrolysis method to prepare high-purity pseudo-boehmite as raw material, breaks through the technical problem of preparation of high-purity alumina balls through a large number of technical public relations, and provides a brand new idea for preparing wear-resistant high-purity alumina grinding medium.

Disclosure of Invention

The invention aims to solve the problems of low purity and poor wear resistance of the alumina grinding ball in the prior art by analyzing the problems of the alumina grinding ball prepared by the existing rolling forming method according to the powder characteristics, the forming and sintering mechanism, and provides the preparation method of the wear-resistant high-purity alumina grinding ball.

The preparation method of the wear-resistant high-purity alumina grinding ball comprises the following steps:

A) the high-purity pseudo-boehmite prepared by the alkoxide hydrolysis method is roasted at the low temperature of 1100 ℃ at 500-.

B) Adding 95 aluminum oxide grinding balls (the content of aluminum oxide is 95%) and the aluminum oxide powder into a grinding machine according to the mass ratio of 10-2:1, adding high-purity water and a dispersing agent, and carrying out wet grinding for 4-6 hours to obtain slurry;

C) the slurry is sieved by a 325-mesh nylon sieve and then dried to obtain monodisperse pure-phase alpha-alumina superfine powder;

D) preparing high-purity alumina sol from the high-purity pseudo-boehmite, then preparing a spherical alumina precursor by spray granulation, and then roasting at the temperature of 600-1150 ℃ to obtain spherical alumina seeds with the size of 40-100 mu m.

C) Rolling and forming, namely adding small ball seeds; then continuously adding the prepared powder, spraying an adhesive, and continuously rolling and growing up to obtain an alumina sphere blank with the particle size of 1-20 mm;

D) introducing the high-purity alumina ball blank into liquid rubber for dipping, taking out, airing, curing, then placing into cold isostatic pressing equipment for secondary pressure forming, and then degumming at the temperature of 250-450 ℃;

E) sintering in high temperature furnace at 1450-1600 deg.c for 1-6 hr, and polishing to obtain the product.

F) And then using the prepared alumina grinding medium, and continuously improving and upgrading the purity of the prepared alumina through an iterative mode operation to finally obtain the high-purity alumina grinding ball with the purity of more than 4N.

Preferably, the process conditions of the 5N high-purity alumina powder prepared by the alkoxide method in the step A) are as follows: the high-purity pseudo-boehmite prepared by hydrolyzing the aluminum isopropoxide is roasted at 1050 ℃ under 900-;

preferably, the weight ratio of the high-purity water and the 5N high-purity alumina powder in the step B) is 5: 1-2: 1;

preferably, the dispersant in the step B) is polyacrylic acid ammonia, OP-10, SPAN-80 and the like, and the using amount of the dispersant is 0.01-0.5 percent of the weight of the high-purity water;

preferably, the rotating speed of the rolling forming method in the step C) is 20-100 r/min;

preferably, the aqueous adhesive in the step C) is an organic adhesive which can be one or a mixture of more than two of PVA, hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxypropyl methylcellulose and gelatin, a composite binder of high-purity aluminum sol, and the organic adhesive: high-purity aluminum sol: 10-20% of deionized water: 0.5-10%: 70-85%; (ii) a

Preferably, the high-purity aluminum sol in the step C) is prepared by adding high-purity pseudo-boehmite prepared by alkoxide hydrolysis, wherein the proportion of the high-purity pseudo-boehmite in deionized water is 10-30%, then adding one or more of sulfuric acid, nitric acid, acetic acid and oxalic acid, stirring at 80-90 ℃ for 0.5-24h, and gelling.

Preferably, the cold isostatic pressure in the step D) is 80-120Mpa, secondary pressure forming is carried out, and then degumming is carried out at 350-450 ℃;

preferably, the sintering schedule in the step E) is sintering at 1450-1600 ℃ for 4-6 hours, and then slowly cooling to room temperature.

Preferably, the prepared and upgraded alumina balls are adopted to continuously grind the high-purity alumina powder, the operation is carried out in an iterative mode, the continuous upgrading and purification are carried out, and finally the wear-resistant high-purity alumina grinding balls with the purity of more than 4N are prepared.

The invention firstly adopts the alkoxide method to prepare monodisperse high-purity nano-alumina, single crystal pure alpha-Al₂O₃The grain size is less than 200nm, and the high sintering activity alumina raw material is provided; secondly, an organic binder and a high-purity aluminum sol composite binder are adopted, the organic binder improves the blank bonding strength at low temperature, and the aluminum sol improves the bonding performance of the ceramic at high temperature; thirdly, the spherical alumina prepared by spraying and granulating the alumina sol is used as a seed, and the seed prepared by the method has good fluidity, small and uniform size and easy control of the size; the method combining rolling preforming and cold isostatic pressing solves the defects of low density, low strength, poor wear resistance and the like of a green body after the green body is sintered by only using rolling forming at present; and finally, the purity of the final product is improved through an iterative and updated preparation idea. The process greatly improves the high density and the strength of the sintered alumina balls, finally prepares the high-purity alumina grinding balls with fine grains, low abrasion and high strength, and continuously upgrades the product purity along with iterative update.

The abrasion detection method comprises the following steps:

(1) the grinding tank adopts a 10L polyurethane tank;

(2) abrasion resistance impact testing machine: 3kg of alumina balls, 1kg of alumina powder and 3L of tap water are filled in the reactor, and the reactor is continuously operated at 100 r/min;

(3) grinding for 10h, taking out a sample, washing with water, and drying for later use;

(4) before and after grinding, weighing and calculating abrasion.

Detailed Description