JP5242366B2 - Zirconium oxide, precursor thereof, and production method thereof - Google Patents

Description

  The present invention relates to a zirconium oxide, a precursor thereof and a production method thereof, a zirconium composite oxide, a precursor thereof and a production method thereof. More specifically, it has excellent heat resistance and corrosion resistance, and has a high melting point, and is a zirconium oxide that can be applied to many fields such as recent catalysts, refractories, fine ceramics, and precursors thereof. Bodies and their production methods, zirconium composite oxides, precursors thereof, and production methods thereof.

  Conventionally, using a zirconium aqueous solution as a starting material, (1) a method of coprecipitation by adding ammonia water, etc., (2) a method of hydrolyzing and replacing the precipitate in an organic solvent, (3) hydrolysis at a high temperature and high pressure And (4) a method of synthesizing an alkoxide compound and hydrolyzing it.

  However, in the case of the above method (1), the obtained hydroxide is hard and requires a considerable pulverization treatment to make a fine powder. In the case of the method (2), the hydrolysis rate is slow, Processing for several tens to hundreds of hours is required, and organic solvent recovery equipment and explosion-proof equipment are required, resulting in high energy costs. In the case of method (3), an autoclave is required. In the case of the method (4), there are serious problems such as high energy costs and the necessity of a process for synthesizing an organometallic compound, which requires considerable chemical costs.

  With regard to such problems, first, the method (1) is mainly improved, and at least one stabilizing element selected from the group consisting of yttrium, calcium, magnesium, aluminum and rare earth elements, sulfate radical and zirconium is added. A first step of obtaining a slurry in which a precipitate of zirconium basic sulfate adsorbed with a part of the stabilizing element is deposited by raising the temperature of the dissolved raw material aqueous solution to 50 ° C. or higher; In the second step, the pH is increased to 8 or more to elute the sulfate radicals in the precipitate, and the stabilizing element dissolved in the slurry is coprecipitated as a hydroxide in the precipitate. A third step of solid-liquid separation of the obtained slurry to obtain a fine powder of zirconium hydroxide containing the hydroxide of the stabilizing element; That a fourth step of roasting the powder has been disclosed (Patent Document 1).

JP 2003-206137 A

  However, in the method described in Patent Document 1, impurities such as Na of alkali metal atoms and S derived from alkali metal hydroxide and sulfate radicals, which are impurities contained in the fine powder of zirconium hydroxide, are included. If contained in electronic components, etc., there is a risk of adverse effects, and a large amount of pure water or ammonia water is required to clean this impurity, and as a result, a large amount of industrial wastewater may be discharged during the manufacturing process. .

  In view of the above-described conventional problems, the present invention provides a high-purity zirconium oxide having a low impurity content and powder thereof without performing cleaning using a large amount of pure water or ammonia water found in conventional manufacturing methods. A precursor and a method for producing a zirconium oxide obtained by firing the precursor are provided.

  The method for producing a zirconium oxide powder precursor according to the present invention includes (1) heating a raw material solution in which a water-soluble zirconium salt and a sulfate radical are dissolved, and a slurry in which a precipitate of a basic zirconium sulfate salt is deposited. A reaction step to be obtained; (2) a neutralization step in which alkali is added to the slurry and the pH is set to 11 or more to completely elute the sulfate radical; and (3) solid-liquid separation of the slurry obtained in the neutralization step And a cleaning step of obtaining a zirconium hydroxide powder by performing cleaning with an acid at a pH of 9 or less.

  The raw material in which the reaction step (1) dissolves a water-soluble zirconium salt, a sulfate group, and a water-soluble salt containing at least one selected from the group consisting of alkaline earth metal elements and rare earth elements as stabilizing elements. The step is preferably a step of heating the solution to obtain a slurry in which a precipitate of the basic zirconium sulfate salt on which a part of the stabilizing element is adsorbed is deposited.

  The alkali in the neutralization step (2) is preferably sodium hydroxide, and the pH in the neutralization step (2) is preferably 11-12.

  The acid in the washing step (3) is preferably hydrochloric acid, and the pH in the washing step (3) is preferably 7-8.

  The zirconium oxide powder precursor according to the present invention is a zirconium oxide powder precursor obtained by the above production method.

  The zirconium composite oxide of the present invention is produced by firing the zirconium composite oxide powder precursor obtained by the above production method.

  According to the present invention, there is provided a high-purity zirconium oxide having a low impurity content, a precursor thereof, and a method for producing them without performing the cleaning using a large amount of pure water or ammonia water found in a conventional production method. can do.

  The method for producing a zirconium oxide precursor of the present invention includes (1) a reaction step of heating a raw material solution in which a water-soluble zirconium salt and a sulfate group are dissolved to obtain a slurry in which a precipitate of a basic zirconium sulfate salt is deposited; (2) a neutralization step in which alkali is added to the slurry and the pH is set to 11 or more to completely elute the sulfate radical; and (3) the slurry obtained in the neutralization step is subjected to solid-liquid separation, It is characterized by comprising a washing step of carrying out washing at a pH of 9 or less to obtain zirconium hydroxide powder.

  Hereinafter, each process will be described in more detail.

  First, the step (1) is a step in which a raw material solution in which a water-soluble zirconium salt and a sulfate radical are dissolved is heated to obtain a slurry in which a precipitate of a basic zirconium sulfate salt is deposited. Here, zirconium oxychloride, zirconium nitrate, etc. can be used as the water-soluble zirconium salt, but zirconium oxychloride is preferred from the viewpoint of industrial and drainage load. As the sulfate radical, sulfuric acid, sodium sulfate, ammonium sulfate and the like can be used, but sodium sulfate is preferable from the viewpoint of industrial and drainage load. Regarding the blending of the zirconium and the sulfate radical, the sulfate radical is preferably in a molar ratio of about 0.4 to 0.6 with respect to the mole of zirconium. When the molar ratio is less than 0.3, there is a problem that a basic zirconium sulfate salt is not formed. When the molar ratio exceeds 0.8, there is a problem that unintended precipitation (zirconium sulfate or the like) occurs. The temperature of the raw material solution is preferably about 60 to 90 ° C. When the temperature is less than 60 ° C., there is a problem that the generation is extremely slow. The heating time is preferably about 1 to 2 hours. When the heating time is less than 0.5 hour, there is a problem that unreacted substances remain, and when the heating time exceeds 2 hours, there is a problem in that it is economically undesirable because most of the reaction has already been completed.

  The step (1) comprises a raw material solution in which a water-soluble zirconium salt, a sulfate group, and a water-soluble salt containing at least one selected from the group consisting of alkaline earth metal elements and rare earth elements as stabilizing elements are dissolved. The step is preferably a step of heating to obtain a slurry in which a precipitate of a basic zirconium sulfate salt on which a part of the stabilizing element is adsorbed is deposited.

  Here, the stabilizing element is used to stabilize the crystal structure of zirconia and improve physical properties such as strength of the sintered body. These elements can be appropriately selected for the kind and amount of addition depending on the required physical properties.

  Examples of the stabilizing element include Be, Mg, Ca, Sr, Ba, Sc, Y, La, Ce, Pr, Nd, Eu, Gd, and Yb. Among these, Y is used from the viewpoint of improving mechanical strength. Mg and Ca are preferable from the viewpoint of improving heat resistance, and Ba, Ce, Sr and their composite systems are preferable from the viewpoint of catalyst performance.

  The above-mentioned conditions can be applied to the temperature and time for heating the raw material solution.

  Next, the step (2) is a neutralization step in which an alkali is added to the slurry obtained in the step (1) to make the pH 11 or higher and the sulfate radicals are completely eluted. Here, sodium hydroxide, potassium hydroxide, ammonia or the like can be used as the alkali, but sodium hydroxide is preferable from the viewpoint of industrial and drainage load. Moreover, the said pH should just be 11 or more, and it is preferable that it is 11-12. When the pH is less than 11, there is a problem that the sulfate radical remains. Moreover, when pH exceeds 12, there exists a tendency for the residue of a large excess Na to occur. It should be noted that the determination of whether the sulfuric acid has completely eluted can be made when the pH reaches equilibrium. Furthermore, it can be confirmed with a pH meter whether the slurry has been neutralized.

  Next, in the step (3), the neutralized slurry obtained in the step (2) is subjected to solid-liquid separation, and the pH is adjusted to 9 or less with an acid to obtain a zirconium hydroxide powder. It is a cleaning process. Here, hydrochloric acid, nitric acid and the like can be used as the acid, but hydrochloric acid is preferable from the viewpoint of industrial and drainage load. Moreover, it is preferable that the said pH in the process of (3) is 7-8. When pH is less than 7, there exists a problem that a useful component elutes, and when pH exceeds 8, there exists a problem that the residue of Na occurs. Solid-liquid separation and washing can be performed by various methods obvious to those skilled in the art. The pH can be confirmed with a pH meter. In the case of an oxide precursor, it is often provided in a squeezed state (wet powder), and the oxide can be obtained by baking with the wet powder.

  A zirconium oxide precursor can be manufactured by the above process.

  Next, the manufacturing method of the zirconium oxide of this invention is demonstrated.

  The zirconium oxide of the present invention can be obtained by firing the zirconium oxide powder precursor obtained by the above production method. The firing temperature can be changed depending on the target powder physical properties, but the firing temperature is preferably about 500 to 1200 ° C. When the firing temperature is less than 500 ° C., there is a problem that it is not oxidized, and when it exceeds 1200 ° C., there is a problem that strong aggregation occurs due to grain growth. Furthermore, although the firing time varies depending on the type of electric furnace, gas furnace, etc., the size of the firing furnace, etc., it is preferable to perform firing until the temperature in the system becomes uniform.

  EXAMPLES Hereinafter, although an Example demonstrates this invention more concretely, this invention is not limited to these.

Example 1
As a zirconium solution, zirconium oxychloride was dissolved in pure water to prepare an aqueous solution with a ZrO ₂ concentration of 10 wt%, and anhydrous sodium sulfate powder as a sulfate radical adjuster.

To 2000 g of the zirconium aqueous solution, 100 g corresponding to 0.6 mol of ZrO ₂ mol of anhydrous sodium sulfate powder as a sulfate radical adjusting agent was added to obtain a raw material aqueous solution.

  This raw material aqueous solution was heated to 80 ° C. and held for 1 hour in a heated state to obtain a slurry in which zirconia basic sulfate was precipitated. A 48% aqueous sodium hydroxide solution was added to the slurry as a pH adjuster until the pH reached 11.5, and then maintained for 15 minutes to obtain a slurry in which zirconium hydroxide was precipitated.

  The obtained slurry was subjected to suction filtration with a Nutsche, and washed with 10 L of pure water per kg of oxide. The obtained hydroxide was further reslurried with 2.5 L of pure water per oxide-kg, the pH was adjusted to 7.0 with hydrochloric acid, suction filtered with Nutsche, and 7. After washing with 5 L of pure water, drying was performed in the air in a 110 ° C. constant temperature bath to obtain a precursor hydroxide. The amount of impurities in the obtained precursor hydroxide is shown in Table 1.

  The precursor hydroxide was calcined at 1000 ° C. in the atmosphere with an electric furnace to obtain zirconia powder.

Example 2
As a zirconium solution, an aqueous solution in which zirconium oxychloride is dissolved in pure water to a ZrO ₂ concentration of 10 wt%, an aqueous solution in which yttrium oxide is dissolved in hydrochloric acid as a stabilizer solution to a Y ₂ O ₃ concentration of 15 wt%, sulfuric acid Anhydrous sodium sulfate powder was prepared as a root adjuster.

The zirconium aqueous solution was mixed with 2000 g, and the stabilizer aqueous solution was mixed with 60 g of an aqueous solution corresponding to 3.0 mol% per ₂ mol of ZrO, and anhydrous sodium sulfate powder as a sulfate radical adjusting agent was mixed with ZrO. 90 g corresponding to 0.5 mol per ₂ mol was added to obtain a raw material aqueous solution.

  This raw material aqueous solution was heated to 80 ° C. and held for 1 hour in a heated state to obtain a slurry in which zirconia basic sulfate was precipitated. A 48% aqueous sodium hydroxide solution was added to the slurry as a pH adjuster until the pH reached 11.5, and then maintained for 15 minutes to obtain a slurry in which the stabilizing element was coprecipitated.

  The obtained slurry was subjected to suction filtration with a Nutsche, and washed with 10 L of pure water per kg of oxide. The obtained hydroxide was further reslurried with 2.5 L of pure water per oxide-kg, the pH was adjusted to 8.0 with hydrochloric acid, suction filtered with Nutsche, and 7. After washing with 5 L of pure water, drying was performed in the air in a 110 ° C. constant temperature bath to obtain a precursor hydroxide. The amount of impurities in the obtained precursor hydroxide is shown in Table 1.

  The precursor hydroxide was calcined at 1000 ° C. in the atmosphere with an electric furnace to obtain partially stabilized zirconia powder.

Example 3
As a zirconium solution, an aqueous solution in which zirconium oxychloride is dissolved in pure water to have a ZrO ₂ concentration of 10 wt%, an aqueous solution in which strontium chloride is dissolved in pure water to have a SrO concentration of 10 wt%, and yttrium oxide as a stabilizer solution Was dissolved in hydrochloric acid to prepare an aqueous solution with a Y ₂ O ₃ concentration of 15 wt%, and anhydrous sodium sulfate powder was prepared as a sulfate radical conditioner.

1000 g of the zirconium aqueous solution, 1000 g of the strontium aqueous solution, and 120 g of an aqueous solution equivalent to 6.0 mol of ZrO ₂ mol per mole of ZrO are mixed, and this mixture is mixed with anhydrous sulfate radical adjuster. 90 g of sodium sulfate powder corresponding to 0.5 mol per ₂ mol of ZrO was added to prepare a raw material aqueous solution.

  This raw material aqueous solution was heated to 80 ° C. and held for 1 hour in a heated state to obtain a slurry in which zirconia basic sulfate was precipitated. A 48% aqueous sodium hydroxide solution was added to the slurry as a pH adjusting agent until the pH reached 11.5, and then maintained for 15 minutes to obtain a slurry in which strontium hydroxide and a stabilizing element were coprecipitated.

  The obtained slurry was subjected to suction filtration with a Nutsche, and washed with 10 L of pure water per kg of oxide. The obtained hydroxide was further reslurried with 2.5 L of pure water per oxide-kg, the pH was adjusted to 8.0 with hydrochloric acid, suction filtered with Nutsche, and 7. After washing with 5 L of pure water, drying was performed in the air in a 110 ° C. constant temperature bath to obtain a precursor hydroxide. The amount of impurities in the obtained precursor hydroxide is shown in Table 1.

  The obtained precursor hydroxide was calcined in the same manner as in Example 1 to obtain a zirconia composite oxide powder.

Comparative Example 1
As a zirconium solution, zirconium oxychloride was dissolved in pure water to prepare an aqueous solution with a ZrO ₂ concentration of 10 wt%, and anhydrous sodium sulfate powder as a sulfate radical adjuster.

2000 g of the zirconium aqueous solution and 100 g corresponding to 0.6 mol of ZrO ₂ mol of anhydrous sodium sulfate powder as a sulfate radical adjusting agent were added to the aqueous solution to obtain a raw material aqueous solution.

  This raw material aqueous solution was heated to 80 ° C. and held for 1 hour in a heated state to obtain a slurry in which zirconia basic sulfate was precipitated. A 48% aqueous sodium hydroxide solution was added to the slurry as a pH adjuster until the pH reached 11.0 and then held for 15 minutes to obtain a slurry in which zirconium hydroxide was precipitated.

  The obtained slurry was subjected to suction filtration with Nutsche, and washed with pure water equivalent to 20 L per oxide-kg. The obtained hydroxide was dried in the air at 110 ° C. in a constant temperature bath to obtain a precursor hydroxide. The amount of impurities in the obtained precursor hydroxide is shown in Table 1. Table 1 shows the amount of cleaning water required when additional cleaning was performed until the amount of impurities was the same as in the examples.

  The obtained precursor hydroxide was calcined in the same manner as in Example 1 to obtain zirconia powder.

Comparative Example 2
As a zirconium solution, zirconium oxychloride was dissolved in pure water to prepare an aqueous solution with a ZrO ₂ concentration of 10 wt%, and anhydrous sodium sulfate powder as a sulfate radical adjuster.

2000 g of the zirconium aqueous solution and 100 g corresponding to 0.6 mol of ZrO ₂ mol of anhydrous sodium sulfate powder as a sulfate radical adjusting agent were added to the aqueous solution to obtain a raw material aqueous solution.

  This raw material aqueous solution was heated to 80 ° C. and held for 1 hour in a heated state to obtain a slurry in which zirconia basic sulfate was precipitated. A 48% aqueous sodium hydroxide solution was added to the slurry as a pH adjusting agent until the pH reached 9.5, and then maintained for 15 minutes to obtain a slurry in which zirconium hydroxide was precipitated.

  The obtained slurry was subjected to suction filtration with Nutsche, and washed with pure water equivalent to 20 L per oxide-kg. The obtained hydroxide was dried in the air at 110 ° C. in a constant temperature bath to obtain a precursor hydroxide. The amount of impurities in the obtained precursor hydroxide is shown in Table 1. Table 1 shows the amount of cleaning water required when additional cleaning was performed until the amount of impurities was the same as in the examples.

  The obtained precursor hydroxide was calcined in the same manner as in Example 1 to obtain zirconia powder.

Comparative Example 3
As a zirconium solution, an aqueous solution in which zirconium oxychloride is dissolved in pure water to a ZrO ₂ concentration of 10 wt%, an aqueous solution in which yttrium oxide is dissolved in hydrochloric acid as a stabilizer solution to a Y ₂ O ₃ concentration of 15 wt%, sulfuric acid Anhydrous sodium sulfate powder was prepared as a root adjuster.

The zirconium aqueous solution was mixed with 2000 g, and the stabilizer aqueous solution was mixed with 60 g of an aqueous solution corresponding to 3.0 mol% per ₂ mol of ZrO, and anhydrous sodium sulfate powder as a sulfate radical adjusting agent was mixed with ZrO. 90 g corresponding to 0.5 mol per ₂ mol was added to obtain a raw material aqueous solution.

  This raw material aqueous solution was heated to 80 ° C. and held for 1 hour in a heated state to obtain a slurry in which zirconia basic sulfate was precipitated. A 48% aqueous sodium hydroxide solution was added to the slurry as a pH adjuster until the pH reached 11.5, and then maintained for 15 minutes to obtain a slurry in which the stabilizing elements were coprecipitated.

  The obtained slurry was subjected to suction filtration with Nutsche, and washed with pure water equivalent to 20 L per oxide-kg. The obtained hydroxide was dried in the air at 110 ° C. in a constant temperature bath to obtain a precursor hydroxide. The amount of impurities in the obtained precursor hydroxide is shown in Table 1. Table 1 shows the amount of cleaning water required when additional cleaning was performed until the amount of impurities was the same as in the examples.

  The obtained precursor hydroxide was calcined in the same manner as in Example 1 to obtain partially stabilized zirconia powder.

Comparative Example 4
As a zirconium solution, an aqueous solution in which zirconium oxychloride is dissolved in pure water to a ZrO ₂ concentration of 10 wt%, an aqueous solution in which yttrium oxide is dissolved in hydrochloric acid as a stabilizer solution to a Y ₂ O ₃ concentration of 15 wt%, sulfuric acid Anhydrous sodium sulfate powder was prepared as a root adjuster.

The zirconium aqueous solution was mixed with 2000 g, and the stabilizer aqueous solution was mixed with 60 g of an aqueous solution corresponding to 3.0 mol% per ₂ mol of ZrO, and anhydrous sodium sulfate powder as a sulfate radical adjusting agent was mixed with ZrO. 90 g corresponding to 0.5 mol per ₂ mol was added to obtain a raw material aqueous solution.

  This raw material aqueous solution was heated to 80 ° C. and held for 1 hour in a heated state to obtain a slurry in which zirconia basic sulfate was precipitated. A 48% aqueous sodium hydroxide solution was added to the slurry as a pH adjuster until the pH was 8.5, and then maintained for 15 minutes to obtain a slurry in which the stabilizing element was coprecipitated.

  The obtained slurry was subjected to suction filtration with Nutsche, and washed with pure water equivalent to 20 L per oxide-kg. The obtained hydroxide was dried in the air at 110 ° C. in a constant temperature bath to obtain a precursor hydroxide. The amount of impurities in the obtained precursor hydroxide is shown in Table 1. Table 1 shows the amount of cleaning water required when additional cleaning was performed until the amount of impurities was the same as in the examples.

  The obtained precursor hydroxide was calcined in the same manner as in Example 1 to obtain partially stabilized zirconia powder.

Comparative Example 5
As a zirconium solution, an aqueous solution in which zirconium oxychloride is dissolved in pure water to have a ZrO ₂ concentration of 10 wt%, an aqueous solution in which strontium chloride is dissolved in pure water to have a SrO concentration of 10 wt%, and yttrium oxide as a stabilizer solution Was dissolved in hydrochloric acid to prepare an aqueous solution with a Y ₂ O ₃ concentration of 15 wt%, and anhydrous sodium sulfate powder was prepared as a sulfate radical conditioner.

1000 g of the zirconium aqueous solution, 1000 g of the strontium aqueous solution, and 120 g of an aqueous solution equivalent to 6.0 mol of ZrO ₂ mol per mole of ZrO are mixed, and this mixture is mixed with anhydrous sulfate radical adjuster. 90 g of sodium sulfate powder corresponding to 0.5 mol per ₂ mol of ZrO was added to prepare a raw material aqueous solution.

  This raw material aqueous solution was heated to 80 ° C. and held for 1 hour in a heated state to obtain a slurry in which zirconia basic sulfate was precipitated. A 48% aqueous sodium hydroxide solution was added to the slurry as a pH adjuster until the pH was 9.0, and then maintained for 15 minutes to obtain a slurry in which strontium hydroxide and a stabilizing element were coprecipitated.

  The obtained slurry was subjected to suction filtration with a Nutsche, and washed with 20 L of pure water per kg of acid red product. The obtained hydroxide was dried in the air at 110 ° C. in a constant temperature bath to obtain a precursor hydroxide. The amount of impurities in the obtained precursor hydroxide is shown in Table 1. Table 1 shows the amount of cleaning water required when additional cleaning was performed until the amount of impurities was the same as in the examples.

  The obtained precursor hydroxide was calcined in the same manner as in Example 1 to obtain a zirconia composite oxide powder.

Comparative Example 6
As a zirconium solution, an aqueous solution in which zirconium oxychloride is dissolved in pure water to have a ZrO ₂ concentration of 10 wt%, an aqueous solution in which strontium chloride is dissolved in pure water to have a SrO concentration of 10 wt%, and yttrium oxide as a stabilizer solution Was dissolved in hydrochloric acid to prepare an aqueous solution with a Y ₂ O ₃ concentration of 15 wt%, and anhydrous sodium sulfate powder was prepared as a sulfate radical conditioner.

1000 g of the zirconium aqueous solution, 1000 g of the strontium aqueous solution, and 120 g of an aqueous solution equivalent to 6.0 mol of ZrO ₂ mol per mole of ZrO are mixed, and this mixture is mixed with anhydrous sulfate radical adjuster. 90 g of sodium sulfate powder corresponding to 0.5 mol per ₂ mol of ZrO was added to prepare a raw material aqueous solution.

  This raw material aqueous solution was heated to 80 ° C. and held for 1 hour in a heated state to obtain a slurry in which zirconia basic sulfate was precipitated. A 48% aqueous sodium hydroxide solution was added to the slurry as a pH adjusting agent until the pH reached 11.5, and then maintained for 15 minutes to obtain a slurry in which strontium hydroxide and a stabilizing element were coprecipitated.

  The obtained slurry was subjected to suction filtration with Nutsche, and washed with pure water equivalent to 20 L per oxide-kg. The obtained hydroxide was dried in the air at 110 ° C. in a constant temperature bath to obtain a precursor hydroxide. The amount of impurities in the obtained precursor hydroxide is shown in Table 1. Table 1 shows the amount of cleaning water required when additional cleaning was performed until the amount of impurities was the same as in the examples.

  The obtained precursor hydroxide was calcined in the same manner as in Example 1 to obtain a zirconia composite oxide powder.

  As described above, according to the zirconium oxide, the precursor thereof, and the production method thereof, the zirconium composite oxide, the precursor, and the production method of the present invention, cleaning using a large amount of pure water or ammonia water is not performed. Further, it is possible to provide a high-purity zirconium oxide having a low impurity content, a precursor thereof and a production method thereof, a zirconium composite oxide, a precursor thereof and a production method thereof.

Claims (4)

(1) a reaction step of heating a raw material solution in which a water-soluble zirconium salt and a sulfate group are dissolved to obtain a slurry in which a precipitate of a basic zirconium sulfate salt is deposited;
(2) a neutralization step in which an alkali is added to the slurry, the pH is set to 11 or more, and the sulfate radical is completely eluted;
(3) The slurry obtained in the neutralization step is subjected to solid-liquid separation, and the pH is adjusted to 7 to 8 with hydrochloric acid to perform washing, thereby obtaining a zirconium hydroxide powder. A method for producing a zirconium oxide powder precursor. The raw material in which the reaction step (1) dissolves a water-soluble zirconium salt, a sulfate group, and a water-soluble salt containing at least one selected from the group consisting of alkaline earth metal elements and rare earth elements as stabilizing elements. The method for producing a zirconium oxide powder precursor according to claim 1, which is a step of heating the solution to obtain a slurry in which a precipitate of a basic zirconium sulfate salt on which a part of the stabilizing element is adsorbed is obtained. The zirconium oxide powder according to claim 1 or 2, wherein the alkali in the neutralization step (2) is sodium hydroxide and the pH in the neutralization step (2) is 11 to 12. A method for producing a precursor. A method for producing a zirconium oxide, comprising calcining a zirconium oxide powder precursor obtained by the production method according to any one of claims 1 to 3.