JPS58176127A - Preparation of stabilized zirconia fine powder - Google Patents

Abstract

PURPOSE:To prepare stabilized zirconia fine powder in high purity, at a low cost, by spraying and calcining an aqueous solution of a zirconium salt and a specific stabilizer under specific condition. CONSTITUTION:The zirconium salt is preferably zirconium oxychloride, zirconium sulfate, zirconium nitrate and basic zirconium carbonate, and examples of the stabilizer are salts of calcium, magnesium and yttrium. An aqueous solution or slurry of a zirconium salt and a stabilizer, containing 1-15pts.wt. of Ca, 1- 10pts.wt. of Mg or 2-20pts.wt. of Y per 100pts.wt. of Zr, is sprayed and calcined at 600-2,000 deg.C. The linear velocity of the solution in the spray calcination is 10-500m/min. Stabilized zirconia fine powder having particle size of about <=1mu can be prepared by this process.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing high-purity stabilized zirconia fine powder used in sensors, refractories, ceramics, electronic industries, etc.

Conventionally, stabilized zirconia powder has been used in refractories for continuous casting of steel, electronic materials, and exhaust gas sensors for automobiles. In these fields, stabilized zirconia powders of 1 to several microns have been used, but in recent years, with the demand for higher functionality of products used, submicron stabilized zirconia powders have been required.

The method for producing this submicron stabilized zirconia powder is as follows: 1) zircon sand is roasted with alkali and then treated with acid to form a zirconium salt, to which compounds such as calcium, magnesium and yttrium are added as a stabilizer; After neutralizing with an alkali and then crushing, the baddeleyite is treated with an acid, and the zirconium salt is treated in the same way.

(A method in which a stabilizer is added to zirconium oxychloride or zirconium alkoxide, heated for a long time, hydrolyzed, and the hydroxide is calcined and crushed.

and so on.

In method (1), when neutralizing with alkali,
Since the stabilizer and the zirconium salt have significantly different solubility in the hydroxide solution, it is difficult to obtain a homogeneous stabilized zirconia powder because the stabilizer is uniformly dispersed in the zirconium hydroxide.

Method 0) using hydrolysis can obtain stabilized zirconia mold powder of extremely high purity, but in order to produce in large quantities, the raw materials are expensive and the equipment is also huge, making the production cost high. Become. An electric method may be considered as a simple method, but it is not suitable for obtaining fine powder.

In these alkali neutralization or hydrolysis methods, the hydroxide of zirconium and the hydroxide of the stabilizer are present on or near the respective particles, and during the calcination process, the hydroxide of zirconium and the stabilizer are diffused. It seems that the mechanism is that stabilized zirconia is generated. Therefore, if the pH and temperature control of the solution in the hydroxide coprecipitation step and the calcination step are not sufficient, there is a drawback that some products do not contain the stabilizer as a solid solution.

In addition, although pulverization is currently done mechanically,
This method is not satisfactory in terms of contamination with impurities, difficulty in controlling particle size distribution, etc.

As a result of intensive study to solve the problems of this manufacturing process, the present inventors have developed a method that does not use alkali and does not require pulverization.
An aqueous solution or slurry of lamb salt has been found to produce a low-cost method of producing high-purity stabilized zirconia fine powder directly from a solution.

That is, the present invention provides zirconium salt and carunium,
The present invention provides a method for producing stabilized zirconia fine powder, which comprises spraying and roasting an aqueous solution or slurry solution of a magnesium or yttrium salt at a temperature of 600°C to 2000°C.

The zirconium salt of the present invention is not particularly limited and may be any salt, but preferably zirconium oxychloride, zirconium sulfate, zirconium nitrate or basic zirconium carbonate.

Particularly preferred is zirconium oxychloride.

Calcium, magnesium or yttrium salts can be used as stabilizers. Combinations of these salts and zirconium salts may be selected as appropriate, but preferred are combinations in which the acids produced as by-products from the spray roasting process are the same.

The mixing ratio of the zirconium salt and the stabilizer is not particularly limited as long as the stabilizer is uniformly dispersed, but preferably 100 parts by weight of zirconium is mixed with 1 part of calcium.
~15 parts by weight, 1 to 10 parts by weight of magnesium, or 2 to 20 parts by weight of yttrium. If the mixing ratio of these stabilizers to zirconium is too low, no stabilizing effect will be produced, and if it is too large, the properties of zirconia as a fine powder will be deteriorated, which is not preferable.

As the mixed solution of zirconium salt and stabilizer to be subjected to spray roasting, an aqueous solution or a slurry solution can be used. The aqueous solution may be prepared by a conventional method, and the stabilizer is dissolved in the zirconium salt aqueous solution. It is adjusted by mixing different aqueous solutions. The concentration of these salt aqueous solutions is preferably set to a sufficiently high concentration in a range that does not cause precipitation of salts from the viewpoint of heat balance, and for this purpose, suitable acids such as hydrochloric acid, sulfuric acid, organic acids, etc. may be added.

For spray roasting, use a commonly used spray roasting furnace.
It may be carried out at a temperature of 00°C to 2000°C.

This temperature can be achieved with an oxyhydrogen flame by passing oxygen and hydrogen gas through a burner, but a combustion flame of oxygen-acetylene gas or oxygen-proton gas may also be used. In addition, in order to fully exhibit the features of the present invention, it is necessary to apply a mixed solution of zirconium salt and stabilizer at a rate of 10 to 500 m/m.
It is preferable to perform spray roasting at a linear velocity of 91 in.
Stabilized zirconia fine powder of sub-micron size can be obtained.

In addition, the spray roasting produces acid, which can be easily separated from the product stabilized zirconia mold powder and treated by providing a recovery step.

As described above, the present invention achieves uniform stabilization in any ratio by spray roasting a uniform solution of zirconium salt and a stabilizer, without using alkali, using simple equipment and a simple process. It is possible to obtain stabilized zirconia fine powder in which the agent is dispersed and dissolved.

EXAMPLES The present invention will be explained below with reference to Examples, but the present invention is not limited thereto. All parts and - in the examples are parts by weight and -.

Example 1 Zirconium oxychloride (ZrOClm・8ru0) 24
0 parts and 10 parts of calcium chloride (Call, ) were dissolved in 500 parts KM of water. The mixed solution prepared in this manner was roasted by spray roasting using an oxyhydrogen flame at 1200°C and an Is speed of 70 m+/win to obtain a calcia-stabilized zirconium fine powder having a particle size distribution of α1 to 1 micron.
, the chemical analysis value of this product is ZrOdo9L6chi.

OaO: 4.7chi, sto, :αo s L F
'll, o, : α1 excellent.

The spray roasting furnace includes a 70 mm diameter x 2000-mm roasting furnace equipped with a 20 mm diameter double-tube burner, and a 30 mm diameter roasting furnace.
Use a 0-φx5000 seaweed scrubber.

Example 2 Yttrium chloride (
YOI, ) 15 parts were used, and the roasting temperature was 1500°C.

Linear speed 100I11/! Spray roasting was carried out in the same manner as in Example 1 at 1 Iin to obtain an ittria-stabilized zirconia fine powder having a particle size distribution of α1 to α5 microns. The chemical analysis values of this product are ZrO: 91.4%, Y, Oj:
7.8-, sto,; (L 01 %, Fe, O
, :α01−.

Example 3 In place of the calcium chloride in Example 1, 10 ml of magnesium chloride (Mg01d) was used and spray roasted in the same manner as in Example 1 to obtain magnesia-stabilized zirconia fine powder.

The chemical analysis value of this product is ZrO,:9'j>2%
, MgO: 40 LAG,, 810*
: α 02 TA G , Fe, O, : [103
It was Chi.

Example 4 Zirconium sulfate (Zr(So, ), -4H,O) 2
80 parts and yttrium sulfate (y, (so,),) 15
Spray roasting was carried out in the same manner as in Example 2, except that 500 parts of water was dissolved in 500 parts of water to obtain ittria-stabilized zirconia fine powder with a particle size distribution of α1 to α5 microns. The chemical analysis values of this product are: ZrO,: 92.9%, Y, O,: &8%
, 810. :C1,025G,We,O,:
It was α005-.

Patent applicant: Toyo Soda Kogyo Co., Ltd.

Claims (1)

[Claims] α) Calcium as a zirconium salt and a softening agent,
ff Danesium is a large amount of water made of yztrium salt iw
The method for producing stabilized zirconia mold powder is characterized in that slurry Toryo is heated at a temperature of 400 to 2000°C. (2) The zirconium salt is zirconium oxychloride. The manufacturing method according to claim (1), wherein zirconium sulfate, zirconium nitrate, or basic zircarbonate is used. (2) The mixing ratio of the zirconium salt and the nitriding agent is 110 parts by weight of zirconium to 1 to 1 parts by weight of calcium.
5 parts by weight, 1 to 10 parts by weight of madanesium, or 2 to 20 parts by weight of yttrium. (2) The linear velocity of the solution during spray roasting is 10 to 500 II
/! The manufacturing method according to any one of claims (1) to (2), which is nin.