JPS6011268A - Member for crusher - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a member for a pulverizer that causes less contamination of pulverized materials during pulverization.

In recent years, there has been an increasing demand for pulverization of metals, ceramics, etc. in various industrial fields, and most of them are made using ball mills, tube mills,
Processed by a crusher such as a rod mill, conical mill, tricone mill, jet mill, centrifugal roller mill, centrifugal ball mill, ring roll mill, high-speed ball mill, low-speed ball mill, high-swing ball mill, mortar and pestle, etc., or a friction crushing type. However, because the crushing media such as the inner walls or balls and rolls of this crusher are composed of materials such as steel balls, alumina, glass, porcelain, natural stone, ceramics, plastic, and rubber, there is a The inner walls of the pulverizer and the grinding media wear out or peel off, which causes them to mix into the pulverized material, resulting in a reduction in the purity of the pulverized material.

In view of these circumstances, the inventors of the present invention conducted intensive studies to find a crusher member with excellent impact resistance and abrasion resistance. The present inventors have discovered that the powder has excellent properties, and when used as a part for a pulverizer, there is almost no decrease in the purity of the pulverized product, leading to the completion of the present invention.

That is, the present invention comprises a sintered body of a zirconia solid solution containing 8 to 15 mol % of Ce 01, the average crystal grain size of the sintered body is 2μ or less, the bulk density is 6, and Q B /ca
To provide a member for a crusher, which is characterized by using a zirconia sintered body having a crystalline size of 1 or more, 70% or more of the crystal phase being tetragonal, and the remainder being monoclinic.

The present invention will be explained in more detail below.

The pulverizer member of the present invention is mainly composed of Ce02B to 15 mol% and the remainder 92 to 85 mol% ZrO2. When the amount of C e O2 in the sintered body is less than 8 mol%, monoclinic crystals increase and a crystalline phase with mechanical strength such as impact resistance and physical properties such as abrasion resistance is formed. A sintered body having a substantially tetragonal structure of 70% or more cannot be obtained, and if the proportion of CeO2 exceeds 15 mol%, the sintered body is composed of tetragonal crystals that are stable at room temperature. This is not preferable because the wear resistance of the sintered member itself decreases as the mechanical strength decreases.

Therefore, by simply mixing zirconia powder and cerium oxide in the amounts specified in the present invention and sintering, a sintered body with a crystal structure with monoclinic crystal as the main vibration can be obtained, and the crystal particles are mainly tetragonal at room temperature. It is not possible to obtain a sintered body consisting of

As a method for obtaining a zirconia ceramic exhibiting a tetragonal structure at room temperature within the CeO2/ZrO2 mixing molar ratio range of the present invention, the average particle size of the tetragonal structure may be set to 2 μ or less, preferably 1 μ or less. If, CeO2
The relative density to the theoretical density of the ZrO2 composition sintered body is 90
% or more (beating porosity of 10% or less), preferably 95% or more, by controlling the raw material particle size, particle size distribution, agglomerated particle size, and sintering conditions.

Regarding the above manufacturing conditions, the specific values cannot be determined uniquely depending on the form of the raw materials used, such as solid oxide powder or powder obtained by coprecipitation method, etc., and the pulverization conditions, etc. However, as for the manufacturing method, the average value is Fine zirconia powder with a particle size of 1 μm or less and cerium oxide powder in an amount of 8 to 15 mol % based on the entire mixture are thoroughly mixed, calcined at a temperature of 800 to 1200° C., and then pulverized with a vibration mill. Next, the pulverized raw material particles are sieved to obtain a raw material powder with a particle size of 2μ or less, preferably 1μ or less, and this powder is processed using known methods such as rubber press method, mold molding method, extrusion molding method, injection molding method, etc. After molding according to the molding method described above, the material is placed in a heating furnace and the temperature is gradually raised to 1,350 to 1,650° C., and then held for several hours and fired to obtain a sintered body having a bulk density of 6.0 g/cJ or more.

The zirconia sintered body thus obtained has a tetragonal crystal structure, and its average crystal grain size is 2 μm or less.

If the average crystal grain size exceeds 2μ, it will not be possible to obtain a sintered body containing more than the desired amount of tetragonal blackbody crystals as described above, and the stability of the tetragonal crystals will decrease, and even a slight impact will cause the crystals to change from the tetragonal crystals. This is preferable because it transforms into a monoclinic crystal, which reduces mechanical strength and wear resistance, and when the bulk density of the sintered body does not reach 6.0 g/c111, the fracture energy of the sintered body against external stress is small. This is not preferable because the stability of the square product is also reduced.

The reason why the crusher member made of the zirconia sintered body of the present invention has excellent effects on mechanical strength such as wear resistance and impact resistance is not clear, but it has relatively low hardness and elasticity. According to the X-ray diffraction method, the zirconia sintered body having the physical properties of the present invention is stable at room temperature and contains 16% or more of CeO2. It exhibits a tetragonal diffraction pattern similar to that of a tetragonal crystal, but unlike the stable tetragonal crystal, it exhibits a so-called quasi-diffraction pattern that partially transforms from a tetragonal crystal to a monoclinic crystal due to external stress, such as mechanical stress or thermal stress. Because it is a stable tetragonal crystal, even if a crank occurs due to mechanical stress, a transition from tetragonal to monoclinic occurs at the same time, resulting in volumetric expansion, which absorbs fracture energy and improves mechanical strength. It is presumed that it has excellent effects.

Furthermore, this is a physical property unique to zirconia sintered bodies,
Since it has excellent chemical stability, there is almost no chemical reaction with the pulverized material, and it has the advantage that it can be used for a long time without corrosion of the pulverizer members.

As detailed above, the crusher member made of the zirconia sintered body having the specific physical properties of the present invention has excellent impact resistance and wear resistance, so there is significantly less chance of contamination of the crushed material during crushing. Its industrial value is enormous as it meets the requirements for grinding without contaminating impurities using parts for grinders in various industrial fields.

The present invention will be explained in more detail with reference to Examples below.

Example 1 To 87 mol % of zirconia dioxide powder with an average particle size of 0.03 μ, 13 mol % of cerium nitrate aqueous solution was added in terms of cerium dioxide, and the slurry was sufficiently stirred and mixed to form a slurry. This slurry was then dried and then heated at 100°C. Calcined, C
eO2-ZrO2 powder was obtained.

After pulverizing this powder to an average particle size of 0.1μ with a vibration mill, 1% by weight of polyvinyl alcohol was added to the powder, and it was molded into a sphere with 12 fin diameters using a rubber press (IT/c+J) and placed in an electric furnace. The ball was sintered at a temperature of 1500° C. for 4 hours to obtain a zirconia ball with a diameter of about 10 fins. The sintered ball had a sintered density of 6.20 g/cJ, an average crystal grain size of 1.0 μm, and was composed of substantially 100% tetragonal crystals.

Next, this zirconia sintered ball weighs 5 kg! The ball was inserted into an alumina pot with a capacity of 1, and a 12-hour dry-slip test was performed using a vibration mill with an amplitude of 5 to measure the wear amount of the ball. The results are shown in Table 1. For comparison, the wear amount of the ball was measured in the same manner as above, except that commercially available alumina balls (purity 92%) with a sintered density of 3.62 g/c+J were used instead of the zirconia sintered balls. The results are also shown in Table 1.

Table 1 Example 2 A calcined powder was obtained in the same manner as in the example except that the raw materials shown in Table 2 were used, and then it was molded into a ball and subjected to an abrasion resistance test in the same manner.

The results are shown in Table 2.

Claims (1)

[Claims] It consists of a sintered body of a zirconia solid solution containing 8 to 15 mol% of CeO2, and the average crystal grain size of the sintered body is 2μ.
Hereinafter, a pulverizer member characterized in that a zirconia sintered body having a bulk density of 6.0 g/Cnt or more and in which 70% or more of the crystal phase is tetragonal and the remainder is monoclinic is used.