JPH0220587B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a crusher member, and more particularly to a crusher member such as a lining material and a media used in a dry or wet crusher that pulverizes particles. Currently, fine grinders include ball mills, sand mills, attritors, vibration mills, hammer mills,
Various types of mills, such as jet mills, rod mills, roller mills, mortar and pestle combinations, etc., are widely used. These crushers are devices that use crushing media such as balls and rolls to crush mainly by friction and impact crushing force, and devices that move particles at high speed and crush them using the impact and crushing force. It is broadly divided into different types of equipment. Conventionally, these materials that are easily worn, such as lining materials and media, are
Depending on the type of object to be crushed, natural stone, porcelain, alumina, glass, rubber, plastic, steel, agate, etc. are used, but since these materials are generally prone to abrasion, there is no possibility of wear during the crushing process. Powder is often mixed in, and it is difficult to separate this mixed wear powder, which is a major obstacle in terms of process simplification and product purity. Therefore, for example, when using steel, a de-ironization process is added, or when alumina is crushed, alumina parts are used, or materials that allow a small amount of abrasion powder to be mixed in (rubber Efforts have been made, such as using members made of plastic, plastic, etc. However, in the latest technological fields, such as ceramics, electronic materials, coating materials, powder materials, etc., trace components and their microstructures in the crushed materials that are mixed in during the pulverization process are important in determining the physical properties and quality of the crushed materials. It has become clear that this has a significant impact on management, reliability, etc. In view of the above-mentioned current situation, the inventor of the present invention has conducted various studies to obtain a member that is not easily worn in a crusher, and has found that a zirconia sintered body containing a specific amount of Y ₂ O ₃ satisfies the requirements. With this discovery, we have finally completed the present invention. That is, the present invention provides the following member for a crusher. "It consists of a zirconia sintered body containing 2.0 to 4.5 mol% of Y ₂ O ₃ , and the crystalline phase of the sintered body consists essentially of 10% or more of tetragonal zirconia and the remainder is equiaxed zirconia. The zirconia sintered body is substantially free of monoclinic zirconia, has an average crystal grain size of 4 μm or less, and has a bulk density of 5.8 g/cm ³ or more. Component for a crusher.'' In the component for a crusher of the present invention, it is essential to use a zirconia sintered body that meets the requirements detailed below. (i) The content of Y ₂ O ₃ is 2.0 to 4.5 mol%.
If the content of Y ₂ O ₃ is less than 2.0 mol%,
Monoclinic ZrO ₂ is easily generated during the production of sintered bodies.
When this monoclinic ZrO ₂ is generated, a large volume change occurs due to dislocation, and cracks occur in the sintered body. Therefore, when using such a sintered body as a part for a crusher, it is preferable because it has insufficient resistance to friction, impact, crushing, etc., resulting in low wear resistance and large amounts of wear. do not have. On the other hand, when the content of Y ₂ O ₃ exceeds 4.5 mol%, equiaxed ZrO ₂ becomes excessive, the toughness decreases, the amount of wear on the sintered member itself becomes large, and the diameter of the wear particles also decreases. Since it becomes coarse, it is not suitable as a crusher member. (ii) The crystalline phase of the sintered body contains 10% or more of tetragonal ZrO ₂ . The content of tetragonal _ZrO2 is 20%
It is preferably above, and more preferably in the range of 30 to 70%, but there is no practical problem even if it exceeds this range. If the content of tetragonal _ZrO2 is less than 10%, equiaxed _ZrO2
Since monoclinic ZrO ₂ is produced in an excessive amount or to the extent that it impairs the physical properties of the sintered body, the problems shown in (i) above occur. In addition, since it is generally difficult to accurately separate the tetragonal crystal and the equiaxed crystal, the tetragonal ZrO ₂ in the present invention
The content was measured by the following method. (a).
After grinding the surface of the sintered body with a 600-mesh diamond grindstone, it is finished to a mirror surface with diamond grains of 1 to 5 μm, and the content of monoclinic ZrO ₂ is determined from the intensity ratio (area ratio) of the surface by X-ray diffraction. Measure. The content of monoclinic _ZrO2 was determined by R.C. Garvie et al. in the Journal of American Ceramics Society (J.
Am.Ceram.Soc), 55 [6], 1972, No. 303-305
It was determined by Xm (%) shown in the formula below as reported on page 1. Xm = Im (111) + Im (111/-) / Im (111) + Im (111)
+Ict(111) ×100 (b). Next, the above sample was heated at 1500℃ in an electric furnace.
After holding for 300 hours, it was slowly cooled and crushed in a mortar.
The grain size is 10 μm or less, and the content of monoclinic ZrO ₂ is measured using the same X-ray diffraction method as in (a) above. (c).
Next, the particles with a diameter of 10 μm or less are heated at 500°C in an electric furnace.
After holding for 1000 hours, cool slowly and grind to 5 μm in a mortar.
It is pulverized as follows, and the content of monoclinic ZrO ₂ is measured by the same X-ray diffraction method as in (a) above. (d). Then,
Subtract the value in (a) from the larger value of the monoclinic ZrO ₂ contents obtained in (b) and (c), and use the obtained value to determine the tetragonal ZrO ₂ content. shall be.
This is because the monoclinic ZrO ₂ increased by the treatments (b) and (c) was generated by the transition of most of the tetragonal ZrO ₂ contained in the sintered body before the treatment. It is based on the presumption that it is a thing. (iii) The average grain size of the ZrO ₂ crystals constituting the sintered body is
It should be 4μm or less. When the average grain size of the crystals exceeds 4 μm, the driving force for the transition from tetragonal to monoclinic crystals increases during the cooling process after sintering, and the amount of monoclinic ZrO ₂ increases, and accordingly, the tetragonal crystal becomes larger. As the amount of ZrO ₂ in the system decreases, the stability of the tetragonal system decreases, and even the slightest impact causes a transition from tetragonal to monoclinic, resulting in a decrease in resistance to friction, impact, crushing, etc. , it is difficult to use it as a part for a crusher. For materials of the same composition,
Considering the general principle in ceramics that the smaller the crystal grain size, the stronger the strength,
The average grain size of the ZrO ₂ crystals is more preferably 3 μm or less. (iv) The bulk density of the sintered body shall be 5.8 g/cm ³ or more.
If the bulk density is less than 5.8g/ ^cm3 , friction,
The fracture energy of the sintered body against external stress such as impact becomes smaller, and the stability of the tetragonal ZrO ₂ tends to be lowered. The bulk density of the sintered body is more preferably 5.9 g/cm ³ or more. The crusher member of the present invention, which is used as a lining material, media, etc., is usually manufactured in the following manner.
A Zr compound solution and a Y compound solution are mixed uniformly in a proportion such that 2.0 to 4.5 mol% of Y ₂ O ₃ is contained in ZrO ₂ , dehydrated and dried, and then heated at 400 to 1200 °C.
to obtain ZrO ₂ primary crystal powder with an average particle size of 0.5 μm or less. Next, after dispersing the primary crystal powder by wet pulverization, a wax emulsion,
By adding molding aids such as PVA and CMC, mechanical press, isostatic press, cast molding,
It is molded into a predetermined shape using known ceramic product molding methods such as extrusion molding, injection molding, and granulation molding, and is processed if necessary. The density of the molded body is approximately 2.0 g/cm ³ or more, more preferably approximately 2.5 g/cm ³ or more. The molded body is fired at about 1350 to 1800°C, more preferably at about 1400 to 1750°C, under normal pressure or under pressure to form a sintered body having a bulk density of 5.8 g/cm ³ or more.
If the sintered body is a media, its surface is smoothed if necessary. In the case of a lining material, it is attached or fitted with an adhesive to the inner surface of the pulverizer with which the material to be crushed is to come into contact. When the crusher member of the present invention satisfies the requirements (i) to (iv) above, it can contain HfO, which is usually included in Zr-containing ores and is treated as part of ZrO ₂ unless otherwise specified. In addition, various components ( _{Al 2 O 3} ,
SiO ₂ , TiO ₂ , Fe ₂ O ₃ , MgO, CaO, Na ₂ O, etc.) may be contained up to about 1% each. The reason why the lining material, media, and other parts of a crusher made of the sintered body of the present invention have excellent wear resistance, impact crushing strength, etc. is not clear, but it is presumed to be as follows. Ru. b) The mechanical strength of the sintered body itself is high. (b) Because tetragonal ZrO ₂ is uniformly dispersed,
High fracture toughness. C. Since the hardness is relatively low (H _RA about 89 to 91) and the elastic modulus is low, the mating members that come into contact with each other (for example, media to lining material, media to media, etc.) will not be damaged or worn out. D. Since it has a high specific gravity, when used as a media, it exhibits high crushing ability due to high kinetic energy. (e) It has excellent chemical stability, so corrosion and fatigue are minimal even when stress is applied while in contact with powder or solvents. Example 1 Zirconia powder containing Y ₂ O ₃ in the proportions shown in Table 1-A below and having an average particle size of 0.03 μm or less was wet-dispersed and ground, and wax emulsion 3 was added as a forming aid. % by weight is added and molded using an isostatic press method at a pressure of 1 ton/cm ² .
Table 1 shows the physical properties of the media having a diameter of 15 mm obtained by sintering the compact under the conditions shown in Table 1-B. Samples Nos. 1 to 4 are products of the present invention that satisfy all of the conditions (i) to (iv) above, and samples 5 to 8 are comparative products that do not satisfy at least one of these conditions. Note that only No. 6 uses primary crystal grains with an average grain size of 0.8 μm.

【table】

【table】

[Table] Put 520g of each of the obtained media into a 400ml capacity alumina ball mill, add 160ml of water,
Perform a dry slip test at 100 rpm. After 48 hours of operation,
After the media were taken out, washed and dried, their weight was measured, and the wear rate was calculated from the loss of wear. The results are shown in Table 2.

[Table] As is clear from the results in Table 2 above, it is clear that the media of the present invention has excellent wear resistance. In addition, the particle size of the wear powder generated from sample No. 3 is
It was only 0.1 μm or less. Comparative Examples 1-2 Made of 92% Al ₂ O ₃ , bulk density 3.6 g/cm ³ , diameter 15
When a commercially available media of mm was subjected to the same tear test as in Example 1, the wear rate was 0.35%. Also, bulk density 3.92 made of commercially available 99.5% Al ₂ O ₃
When the same drying test as above was carried out using a media of 15 mm in diameter and g/cm ³ , the wear rate reached as high as 1.2%. Incidentally, the diameter of the abrasion powder generated from these Al ₂ O ₃ media was 0.2 to 0.7 μm. Example 2 A medium was obtained in the same manner as Sample No. 3 of Example 1, except that the diameter of the sintered body was 20 mm. Put 3 kg of the obtained media into an alumina ball mill with a capacity of 2, and add 1 kg of silica (40 to 80 mesh).
Kg and 700 ml of water are added and wet milled at 95 rpm for 24 hours. The weight of crushed silica particles with a particle size of 3 μm or less reaches 45%. Comparative Example 3 Made of 92% Al ₂ O ₃ , bulk density 3.6 g/cm ³ , diameter 20
Example 2 except that a commercially available media of mm was used.
The silica stone is crushed in the same manner. The weight of particles with a particle size of 8 μm or less of the crushed silica was only 27%. Comparative Example 4 A media is obtained in the same manner as in Example 2, except that the content of Y ₂ O ₃ is 1.9 mol %. Many cracks had already occurred on the surface of the media upon completion of firing, and when this was used for wet crushing of silica stone, many fallen zirconia fragments were mixed into the silica powder. Example 3 A molding raw material was prepared using the same primary crystal powder as No. 2 of Example 1, and molded using the eye test press method at a pressure of 1 ton/cm ² to reduce the outer diameter.
Manufactures a mortar with a diameter of 120 mm and an inner diameter of 91 mm, as well as a matching pestle. The surface of the mortar and pestle that comes in contact with the crushed material is
Polish it with a GC whetstone. The firing time and temperature of the compact, as well as the crystal grain size, bulk density, and tetragonal content after firing are the same as those of sample No. 2 in Table 1. Using the mortar and pestle obtained above, 100~
150 mesh fused alumina ( _SiO2 content 0.02%)
Crush 10g by hand until you can't feel any particles on your fingertips. When the ZrO ₂ content in the crushed material was determined by chemical analysis, it was 0.01% or less. Comparative Example 5 When the same crushing operation as in Example 3 was carried out using a commercially available agate mortar and pestle (both dimensions are the same as in Example 3), the main component of agate was found in the crushed material. It contained 0.05% _SiO2 . Example 4 A molding raw material was prepared using the same primary crystal powder as No. 2 of Example 1, and a molding material was prepared using a rotary granulator to form a powder with a diameter of 6 mm.
After forming it into a mm ball, it is baked at 1600℃ for 2 hours.
Media. The grain size of the obtained media is
0.8μm, bulk density 6.01g/cm ³ , tetragonal content
It is 58%. Charge 5 kg of the media to an attritor with a capacity of 4.9 (manufactured by Mitsui Miike Seisakusho), add 1.3 kg of water and 1.3 kg of silica sand, and increase the rotation speed of the agitator.
Grinding is carried out for 4 hours at 200 rpm. In this case, the media loss rate was 0.01%/hr, and the average particle size of the crushed material was 1.5 μm. or,
No iron content from the steel tank was found in the crushed material. Comparative Example 6 Silica sand was crushed in the same manner as in Example 4, except that a commercially available mullite medium with a diameter of 6 mm was used. The media loss rate was 0.58%/hr, and the average particle size of the crushed material was 2.3 μm. Comparative Example 7 Silica sand was crushed in the same manner as in Example 4, except that a commercially available alumina media (Al ₂ O ₃ purity 92%) with a diameter of 6 mm was used. The media loss rate was 0.11%/hr, and the average particle size of the crushed material was 1.8 μm. In addition, iron content from the steel tank was visually observed in the crushed material. Example 5 Using the same zirconia primary crystal powder as No. 2 of Example 1, a tubular shape with an outer diameter of 15.5 mm, a length of 45 mm, a circumferential wall thickness of 4 mm, and a tip end of 10 mm thick was sealed at one end. manufactures lining materials for The obtained tubular body is fitted into the agitator arm of an attritor similar to that in Example 4, fixed with epoxy resin, and silica sand is crushed in the same manner as in Example 4. Even after a total of 100 hours of use, the surface of the zirconia arm lining material was smooth and shiny, and no dimensional change was observed when measuring the outer diameter with a caliper. Comparative Example 8 A tubular lining material was produced in the same manner as in Example 5, except that 92% Al ₂ O ₃ was used, and silica sand was crushed in the same manner as in Comparative Example 7. After a total of 100 hours of use, 0.6 at the circumference
A decrease in wall thickness of mm was observed. Example 6 A central shaft with a blade-shaped swing hammer is rotated at high speed inside a cylinder, and the material to be crushed is supplied from above the cylinder, crushed by the impact of the hammer and centrifugal force, and crushed from a screen placed below the cylinder. In a type of hammer mill that discharges objects, the outer surface of the tip of the 12 hammers has a thickness of 8 mm and a width.
Zirconia sintered lining materials with a length of 45 mm and a length of 26 mm are each bonded with epoxy resin, and glass powder is crushed at 8000 rpm. The sintered body was formed using the same zirconia primary crystal powder as No. 1 in Example 1 at a pressure of 1 ton/cm ² by a mechanical press method, processed into a predetermined shape, and then heated at 1600°C for 2 hours. It is baked for hours,
It has various physical properties similar to Sample No. 1 in Table 1. Even after a total of 300 hours of use, the lining material of the present invention shows extremely little wear and tear, and it is estimated that it can be used for an even longer period of time. Comparative Example 9 A lining material was produced in the same manner as in Example 6, except that 92% Al ₂ O ₃ was used, and it was joined to the hammer of a hammer mill. After a total of 300 hours of use, the wear and tear is significant.
Therefore, it was determined that further use was impossible due to the high risk of damage and vibration caused by the shift of the center of gravity.

Claims (1)

[Claims] 1 Consisting of a zirconia sintered body containing 2.0 to 4.5 mol% of Y ₂ O ₃ , the crystal phase of the sintered body is substantially composed of 10% or more of tetragonal zirconia and the remainder is equiaxed zirconia. The zirconia sintered body is substantially free of monoclinic zirconia, has an average crystal grain size of 4 μm or less, and has a bulk density of 5.8 g/cm ³ or more. Parts for crushers.