阅读说明：本技术 一种高热震低蠕变刚玉加工工艺 (High-thermal-shock low-creep corundum processing technology ) 是由 张恒网 华志高 曹超 于 2021-01-26 设计创作，主要内容包括：本发明提供了一种高热震低蠕变刚玉加工工艺,原料处理步骤,将氧化铝粉粉碎,并对其进行一次除杂,漂洗和一次烘干后形成中间料；母球生长步骤,将所述中间料置于种球成球机中成长为种球后,将所述种球置于母球成球机中继续长大为母球；烧结料预备步骤,将所述母球置于干燥箱内进行二次烘干,形成烧结料；烧结步骤,将所述烧结料送入立式烧结炉中煅烧,改变其晶相结构,形成板状刚玉；粉碎筛选步骤,将板状刚玉进行粉碎,二次除杂后按粒径大小包装存储,完毕。制得的刚玉经显微观测其晶界处杂质更少,晶体之间结合的更加充分,晶体表面微裂纹少,从而致使烧结板状刚玉的热震稳定性和抗蠕变性得到有效提高。(The invention provides a high thermal shock low creep corundum processing technology, which comprises the steps of raw material treatment, crushing alumina powder, removing impurities for one time, rinsing and drying for one time to form an intermediate material; a step of mother ball growth, which is to place the intermediate material in a ball forming mill to grow into a ball, and place the ball in the ball forming mill to continue to grow into a mother ball; a sintered material preparation step, namely placing the mother balls in a drying box for secondary drying to form a sintered material; a sintering step, namely feeding the sintering material into a vertical sintering furnace for calcination, and changing the crystal phase structure of the sintering material to form plate-shaped corundum; and a crushing and screening step, namely crushing the tabular corundum, and packaging and storing the tabular corundum according to the particle size after secondary impurity removal. The prepared corundum has less impurities at the grain boundary through microscopic observation, the bonding between crystals is more sufficient, and the microcracks on the surface of the crystals are less, so that the thermal shock stability and the creep resistance of the sintered plate-shaped corundum are effectively improved.)

1. A high thermal shock low creep corundum processing technology is characterized in that:

a raw material processing step, namely crushing the alumina powder, and carrying out primary impurity removal, rinsing and primary drying on the crushed alumina powder to form an intermediate material;

a step of mother ball growth, which is to place the intermediate material in a ball forming mill to grow into a ball, and place the ball in the ball forming mill to continue to grow into a mother ball;

a sintered material preparation step, namely placing the mother balls in a drying box for secondary drying to form a sintered material;

a sintering step, namely feeding the sintering material into a vertical sintering furnace for calcination, and changing the crystal phase structure of the sintering material to form plate-shaped corundum;

and a crushing and screening step, namely crushing the tabular corundum, and packaging and storing the tabular corundum according to the particle size after secondary impurity removal.

2. The method for producing corundum with high thermal shock and low creep according to claim 1, wherein the method comprises the following steps: in the step of raw material treatment, the grinding material is alumina micro powder with the particle size of 400 meshes.

3. A method for producing corundum of high thermal shock and low creep according to claim 2, characterized in that: in the step of raw material treatment, the first impurity removal is to put the abrasive into an acid solution to be soaked for 3-5 hours to dissolve sodium oxide and ferric oxide impurities, the pH value of the acid solution is 5-6, the acid solution is discharged after dissolution, and the abrasive is rinsed for 3-4 times by using clean water, wherein the rinsing time is 20-30min each time.

4. The production method of the high-thermal-shock low-creep corundum according to claim 1 or 3, wherein in the step of raw material treatment, the step of primary drying is to place the rinsed abrasive in a dryer for drying for 1-2 hours, and the temperature of the dryer is 380 ℃.

5. The method for producing high thermal shock low creep corundum according to claim 1, wherein in the step of mother ball growth, the grain size of the seed ball is 7.5-8.5 mm, the time required by the seed ball is 0.5-1 h, the grain size of the mother ball is 20mm, and the time for mother ball growth is 2-3 h.

6. The method for producing corundum with high thermal shock and low creep according to claim 1, wherein in the step of preparing the sintering material, the secondary drying temperature is 200-260 ℃ and the drying time is 1-2 h.

7. The method for producing corundum with high thermal shock and low creep according to claim 1, wherein the method comprises the following steps: the calcination temperature of the vertical sintering furnace in the sintering step is 1800-2000 ℃, and the sintering time is increased by 1 hour for every 2 tons of the alumina balls.

8. The method for producing corundum with high thermal shock and low creep according to claim 1, wherein the method comprises the following steps: and dust-containing airflow generated in the primary drying and the secondary drying is discharged into the air after being dedusted by the bag-type dust remover.

Technical Field

The invention relates to the technical field of corundum abrasive production processes, in particular to a high thermal shock low creep corundum processing process.

Background

Corundum is a gem stone formed of crystals of alumina, which is inferior in hardness to diamond only, and is mainly used for high-grade abrasive materials due to its low price. Under the condition of meeting production requirements, the size of a lining body is reduced as much as possible, the complexity of the structure is avoided, and the like, so that the thermal shock resistance and the creep resistance of the material can be effectively improved.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention provides a high thermal shock low creep corundum processing technology for reducing impurities of sodium oxide and aluminum oxide.

The invention is realized by adopting the following technical scheme: a high thermal shock low creep corundum processing technology, raw material processing step, pulverize alumina powder, and carry on its impurity removal once, rinse and form the intermediate charge after oven drying once; a step of mother ball growth, which is to place the intermediate material in a ball forming mill to grow into a ball, and place the ball in the ball forming mill to continue to grow into a mother ball; a sintered material preparation step, namely placing the mother balls in a drying box for secondary drying to form a sintered material; a sintering step, namely feeding the sintering material into a vertical sintering furnace for calcination, and changing the crystal phase structure of the sintering material to form plate-shaped corundum; and a crushing and screening step, namely crushing the tabular corundum, and packaging and storing the tabular corundum according to the particle size after secondary impurity removal.

Preferably, in the raw material processing step, the grinding material is alumina micro powder with the particle size of 400 meshes.

Preferably, in the step of raw material treatment, the first impurity removal is to put the abrasive into an acid solution to be soaked for 3-5 hours to dissolve sodium oxide and ferric oxide impurities, the pH value of the acid solution is 5-6, the acid solution is discharged after dissolution, and the abrasive is rinsed with clean water for 3-4 times, wherein the rinsing time is 20-30min each time.

Preferably, in the step of processing the raw materials, the step of primary drying is to place the rinsed abrasive in a dryer for drying for 1-2 hours, and the temperature of the dryer is 380 ℃.

Preferably, in the step of the growth of the cue ball, the grain diameter of the cue ball is 7.5-8.5 mm, the required time of the cue ball is 0.5-1 h, the grain diameter of the cue ball is 20mm, and the growth time of the cue ball is 2-3 h.

Preferably, in the sintering material preparation step, the secondary drying temperature is 200-260 ℃, and the drying time is 1-2 hours.

Preferably, the calcination temperature of the vertical sintering furnace in the sintering step is 1800-2000 ℃, and the sintering time is increased by 1 hour for every 2 tons of the alumina balls.

Preferably, the dust-containing air flow generated in the primary drying and the secondary drying is discharged into the air after being dedusted by the bag-type deduster.

Compared with the prior art, the invention provides a high thermal shock low creep corundum processing technology for preparing low-impurity corundum by using the following steps, alumina powder is crushed, and subjected to primary impurity removal, rinsing and primary drying to form an intermediate material; a step of mother ball growth, which is to place the intermediate material in a ball forming mill to grow into a ball, and place the ball in the ball forming mill to continue to grow into a mother ball; a sintered material preparation step, namely placing the mother balls in a drying box for secondary drying to form a sintered material; a sintering step, namely feeding the sintering material into a vertical sintering furnace for calcination, and changing the crystal phase structure of the sintering material to form plate-shaped corundum; and a crushing and screening step, namely crushing the tabular corundum, and packaging and storing the tabular corundum according to the particle size after secondary impurity removal. The prepared corundum has less impurities at the grain boundary through microscopic observation, the bonding between crystals is more sufficient, and the microcracks on the surface of the crystals are less, so that the thermal shock stability and the creep resistance of the sintered plate-shaped corundum are effectively improved.

Detailed Description

The present invention is further described below with reference to specific embodiments, and it should be noted that, without conflict, any combination between the embodiments or technical features described below may form a new embodiment.

The method comprises the following steps:

1) pulverizing alumina powder

The method comprises the steps of feeding industrial alumina powder with the particle size of 100 meshes (the main component is alumina containing a small amount of sodium oxide and iron oxide impurities), feeding the industrial alumina powder into a ball mill by using a screw feeder, crushing the industrial alumina powder and grinding the industrial alumina powder into a grinding material with the particle size of 400 meshes, wherein in order to avoid generating excessive impurities, a grinding medium in the ball mill does not use a traditional steel ball, the iron impurities can be increased by using the traditional steel ball, the size of the alumina ball is 20-50 mm, and the lining of the ball mill is made of wear-resistant ceramic.

2) Removing impurities at one time

The method comprises the steps of putting a grinding material into a soaking tank for soaking to remove impurities of sodium oxide and iron oxide, wherein the soaking time is 3-5 hours, tap water is put into the soaking tank, the impurities of the sodium oxide enter the water to react to generate NaOH, so that the water is alkaline, the alkaline water can destroy an aluminum oxide structure, boric acid needs to be added into the tap water in advance, the adding amount of the boric acid is 0.05-0.15% of the mass of the tap water, the tap water added with the boric acid is weakly acidic, the pH value of the tap water is 5-6, the impurities of the sodium oxide and the iron oxide react with hydrogen ions in an acidic solution in the interval to produce salt and water, and the aluminum oxide structure cannot be damaged while the impurities of the sodium oxide and the iron oxide are dissolved.

3) Rinsing

Rinsing the soaked abrasive with clear water for 3-4 times (20-30 min each time) to remove iron and sodium ions attached on the surface of the abrasive.

4) One-time drying

And (3) drying the rinsed abrasive in a dryer for 1-2 hours, wherein the temperature of the dryer is 380 ℃. The surface of the material is kept dry to form an intermediate material. The dust-containing airflow for drying is discharged into the air after being dedusted by the bag-type dust remover.

A mother ball growing step:

1) intermediate material forming ball

And (3) feeding the intermediate material into a ball forming mill through a bottom screw feeder, wherein the intermediate material grows into balls through the ball forming mill, the ball growing time is 0.5-1 h, the particle size of the balls is 7.5-8.5 mm, and low-sodium water is required for the water used by the ball forming mill.

2) The ball is continuously grown to form a mother ball

When the ball is used, the size of the ball is controlled through an internal filter screen, the ball with qualified particle size enters a buffer bin, small balls (smaller than 7.5 mm) with unqualified particle size return to a ball forming mill to continue growing, the unqualified balls (larger than 8.5 mm) roll out of the ball forming mill and enter a bag, grinding materials are fed into one end of the ball forming mill, the ball is fed into the other end of the ball forming mill, the ball continues growing into the mother ball with the particle size of 20mm, the growth time of the mother ball is 2-3 h, circular rolling is formed, and high yield and ball forming efficiency are guaranteed.

Preparing a sintering material:

and (3) placing the mother balls with qualified particle sizes into a drying box for secondary drying, wherein the hot air required by flood drying is kiln gas provided by a cooling bin in the vertical sintering furnace, and the kiln gas in the cooling bin is heated and then introduced into the drying box. The drying time is 1-2 h, and the drying temperature in the drying oven is controlled to be 200-260 ℃. The dust-containing airflow for drying is discharged into the air after being dedusted by the bag-type dust remover.

Sintering:

and feeding the sintered material into a vertical sintering furnace for calcining, and changing the crystal phase structure of the sintered material to form the plate-shaped corundum.

And (4) conveying the dried mother balls to a vertical sintering furnace through a plate type lifter for high-temperature sintering by using the vertical sintering furnace. Specifically, after the mother ball enters the vertical sintering furnace, the fuel in the calcining zone of the vertical sintering furnace is combusted to generate high temperature, so that the mother ball is calcined, the calcining temperature is controlled to be 1800-2000 ℃, preferably 1930 ℃, the calcining time is increased by 1 hour for every 2 tons of materials, and the crystal phase structure of the calcined alumina ball is changed. The sintered alumina ball forms corundum with plate-shaped crystal structure.

The corundum produced by the production method has the following detection results of various components: more than or equal to 97.5 to 98.5 percent of alumina, less than or equal to 0.10 to 0.15 percent of SiO2, less than or equal to 0.05 to 0.15 percent of Fe2O3 and less than or equal to 0.1 to 0.2 percent of sodium oxide.

The crystal phase structure is observed under a microscope, the impurities at the crystal boundary of the corundum are less, the combination between crystals is more sufficient, and the microcracks on the surface of the crystals are less, so that the thermal shock stability and the creep resistance of the sintered plate-shaped corundum are effectively improved.

In order to improve the heat effect (the utilization rate of the heat generated by the natural gas), the air participating in calcination is divided into two parts, the first part of air is directly mixed with the natural gas to be directly combusted, the second part of air firstly passes through the material (high-temperature state) at the discharging position to carry out air cooling on the material, the air is heated at the high-temperature discharging position and then is dedusted by using a bag-type dust remover, then the second part of air enters the vertical sintering furnace to flow upwards from the bottom, and after being preheated by the overheated material bed, the air enters the calcination area to be converged with the first part of air and the fuel to be combusted. Therefore, the temperature of the material at the bottom of the vertical sintering furnace can be reduced, the air temperature at the calcining part is heated, the utilization efficiency of heat energy is improved, the material cooling speed is increased, and the production efficiency is improved.

The cooling bin is placed to the mother ball after calcining, uses the air-blower to cool the cooling bin, and in order to improve fuel utilization efficiency, the cooling bin passes through the ventilation pipe with the drying cabinet in the fifth step and is connected for hot-air in the cooling cabinet is blown by the air-blower, carries in the drying cabinet, lasts to cool off the material in the drying cabinet.

Crushing and screening step

1) Pulverizing tabular corundum

The plate-shaped corundum is crushed in a Bamark crusher, and the powder enters storage bins with different grain diameters after being screened. The airflow containing dust generated by crushing and screening is discharged into the air after being dedusted by the bag-type deduster.

2) Secondary impurity removal

Because the corundum has high hardness, when the Bamark crusher crushes, the corundum can generate iron-cutting impurities again due to the collision of the device and the corundum, and the simple substance iron impurities are removed by the magnetic separator again.

3) Packaging and storing

And packaging and storing the corundum after removing impurities according to the particle size.

The above embodiments are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited thereby, and any insubstantial changes and substitutions made by those skilled in the art based on the present invention are within the protection scope of the present invention.