JP2023006287A - Method for collecting titanium component, method for manufacturing titanium oxide and method for manufacturing alkali metal titanate - Google Patents

Abstract

To provide a method for collecting a titanium component or a method for manufacturing titanium oxide from a waste solution including a titanium compound, capable of reducing the collected titanium component or a calcium content in the titanium oxide even when using calcium hydroxide as a neutralizer.SOLUTION: A method for collecting a titanium component comprises: a step (1) of contacting a waste solution including a titanium compound to water to hydrolyze the titanium compound; an aggregation step (2) of performing primary neutralization of adding calcium hydroxide or calcium oxide as a neutralizer to the hydrolyzed treatment solution to be a pH of 1.5 or more and less than 2.5 and performing secondary neutralization so as to be a pH 6.5 or more and 7.5 or less to aggregate titanium hydroxide; and a step (3) of performing acid treatment of contacting the titanium hydroxide aggregate to hydrochloric acid to obtain titanium oxide.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a method for recovering a titanium component, a method for producing titanium oxide, and a method for producing alkali metal titanate.

Conventionally, the polymerization of olefins such as propylene is carried out using a solid catalyst component for olefin polymerization containing magnesium, titanium, an electron-donating compound, halogen and the like. It is produced by contacting a magnesium compound in the form of a magnesium compound and a titanium compound in the form of a solution, optionally in the presence of an electron-donating compound.

When preparing such a solid catalyst component for olefin polymerization or when preparing a catalyst for olefin polymerization from the solid catalyst component, excess titanium compounds not supported on the solid catalyst component and side reactions during preparation A waste liquid containing other titanium compounds produced in the above process is generated.

In the past, titanium compounds were recovered from the waste solution by distillation under reduced pressure, but with this method, solids precipitated on the distillation mother liquor or trays, making it difficult to discharge the distillation still residue and generating differential pressure within the column. Since it is difficult to continue the distillation due to this, the distillation was stopped without sufficiently recovering the titanium compound, and the distillation still residue was discarded.

However, from the viewpoint of effective use of resources and reduction of waste, there are methods for recovering more titanium compounds from distillation bottoms containing titanium compounds that could not be recovered, and methods for reusing the recovered titanium compounds. is now required.

As a method for recovering a titanium compound from a distillation still residue containing these titanium compounds, for example, in Patent Document 1, one titanium compound is recovered from a waste solution containing a titanium compound generated during the preparation of a catalyst component for polymer production. After flash-distilling and recovering a portion, the recovered residue is brought into contact with water to hydrolyze the titanium compound in the recovered residue, the aqueous phase is separated and recovered, neutralized with a base, and the solid matter is aggregated with a flocculant or the like. - A method has been proposed in which the sediment is collected, the water content is reduced to form a press cake, and the press cake is calcined to recover crude titanium oxide.

As a base used for neutralizing the aqueous phase after the separation and recovery, usually, inexpensive and easy-to-handle ammonia water and calcium hydroxide are suitably used.

However, the method described in Patent Document 1 cannot recover a titanium compound of high purity because nitrogen and calcium are mixed in the recovered crude titanium oxide.

Therefore, in the examples of Patent Document 2, a waste liquid containing titanium tetrachloride, diethoxymagnesium, toluene and butane generated when preparing a solid catalyst component for olefin polymerization is brought into contact with water for hydrolysis. Then, sodium hydroxide is added so that the pH becomes 2 to perform a primary neutralization treatment, and then sodium hydroxide is added so that the pH becomes 6.5 to perform a secondary neutralization treatment, Titanium oxide is obtained by aggregating titanium oxide.

Japanese Patent Application Laid-Open No. 2001-261340 JP 2018-80086 A

In the method of Patent Document 2, rutile-type titanium oxide is easily produced instead of anatase-type titanium oxide, and a highly pure titanium compound is obtained at a high yield.

Here, in paragraph number 0035 of Patent Document 2, "In order to obtain high-purity titanium oxide, in order to suppress contamination of foreign substances such as nitrogen and calcium in the obtained titanium oxide, ammonia water or water is used as a neutralizing agent. It is preferable not to use calcium oxide or the like.” As described in Patent Document 2, sodium hydroxide is used as a neutralizing agent in order to obtain a highly pure titanium compound.

Industrially, however, it is necessary to use calcium hydroxide or calcium oxide as a neutralizing agent in order to reduce wastewater treatment costs. Therefore, the inventors of the present invention have investigated and found that when the neutralizing agent used in the method of the example of Patent Document 2 is changed from sodium hydroxide to calcium hydroxide, the resulting titanium hydroxide aggregates. It was found that calcium hydroxide or calcium carbonate with low water solubility remained in the product, and the calcium component could not be removed by subsequent washing.

As a method of utilizing the recovered titanium oxide, it is possible to use it as a raw material for the production of alkali metal titanate. When used, it becomes a source of calcium titanate, which is an impurity. Therefore, it is desired that the content of calcium in the recovered titanium oxide is low.

Accordingly, an object of the present invention is to recover a titanium component from a waste liquid containing a titanium compound, preferably from a waste liquid containing a titanium compound generated during the preparation of a solid catalyst component for olefin polymerization or a catalyst for olefin polymerization. A method for recovering a recovered titanium component or a titanium component having a low calcium content in titanium oxide obtained even if calcium hydroxide or calcium oxide is used as a neutralizing agent in a method or a method for producing titanium oxide, or a method for producing titanium oxide It is to provide a method.

In order to solve the above technical problems, the inventors of the present invention conducted intensive studies and found that a waste liquid containing a titanium compound is brought into contact with water to hydrolyze the titanium compound, and then calcium hydroxide or calcium oxide is used. The calcium content is reduced by contacting the titanium hydroxide aggregates produced by aggregating the titanium hydroxide with hydrochloric acid having a pH of 5.9 or less. The present inventors have found that an aggregate of titanium hydroxide can be obtained, and have completed the present invention based on this finding.

That is, the present invention
(1) A method for recovering a titanium component from a waste liquid containing a titanium compound, comprising:
a step (1) of contacting the waste liquid containing the titanium compound with water to hydrolyze the titanium compound;
The hydrolyzed treatment liquid is subjected to primary neutralization treatment by adding calcium hydroxide or calcium oxide as a neutralizing agent so that the pH becomes 1.5 or more and less than 2.5, and then the primary neutralization. The treated solution is subjected to secondary neutralization treatment by adding calcium hydroxide or calcium oxide as a neutralizing agent so that the pH becomes 6.5 or more and 7.5 or less, and then titanium hydroxide is aggregated. a step (2) of obtaining an aggregate of titanium hydroxide by performing an aggregation treatment to
a step (3), after the step (2), of subjecting the aggregates of titanium hydroxide to acid treatment by contacting the aggregates of titanium hydroxide with hydrochloric acid to obtain an acid-treated product of the aggregates of titanium hydroxide;
having
A method for recovering a titanium component, characterized by;
(2) After the step (2) is performed to obtain the titanium hydroxide aggregate concentrate, the titanium hydroxide aggregate concentrate is separated, and then the titanium hydroxide aggregate is concentrated. (1), characterized in that it has a step (3A) of contacting the substance with hydrochloric acid to acid-treat the aggregate of titanium hydroxide to obtain an acid-treated product of the aggregate of titanium hydroxide. A method for recovering the titanium component;
(3) In the step (3A), a concentrate of the titanium hydroxide agglomerates is obtained by allowing the agglomerates of the titanium hydroxide produced by performing the step (2) to settle (2 ), a method for recovering the titanium component of
(4) In the step (3A), after the step (2) is performed to precipitate the titanium hydroxide aggregate, the precipitate of the titanium hydroxide aggregate is separated, and then the titanium hydroxide is Dehydration treatment is performed to remove the liquid phase from the sediment of the aggregates of ( 2) the method for recovering the titanium component;
(5) After the step (2) is performed to precipitate the titanium hydroxide agglomerate, the sediment of the titanium hydroxide agglomerate is brought into contact with hydrochloric acid to acidify the titanium hydroxide agglomerate. The method for recovering a titanium component according to (1), characterized by having a step (3B) of obtaining an acid-treated titanium hydroxide aggregate;
(6) The titanium according to any one of (1) to (5), characterized by having a washing step of washing the acid-treated aggregate of titanium hydroxide with washing water of 6.0 or more and 9.0 or less. method of recovering the component;
(7) A method for producing titanium oxide from a waste liquid containing a titanium compound, comprising:
a step (1) of contacting the waste liquid containing the titanium compound with water to hydrolyze the titanium compound;
The hydrolyzed treatment liquid is subjected to primary neutralization treatment by adding calcium hydroxide or calcium oxide as a neutralizing agent so that the pH becomes 1.5 or more and less than 2.5, and then the primary neutralization. The treated solution is subjected to secondary neutralization treatment by adding calcium hydroxide or calcium oxide as a neutralizing agent so that the pH becomes 6.5 or more and 7.5 or less, and then titanium hydroxide is aggregated. a step (2) of obtaining an aggregate of titanium hydroxide by performing an aggregation treatment to
a step (3), after the step (2), of subjecting the aggregates of titanium hydroxide to acid treatment by contacting the aggregates of titanium hydroxide with hydrochloric acid to obtain an acid-treated product of the aggregates of titanium hydroxide;
an oxidation step of obtaining titanium oxide by oxidizing the acid-treated aggregate of titanium hydroxide;
having
A method for producing titanium oxide, characterized by;
(8) After obtaining the concentrate of the titanium hydroxide agglomerate produced by performing the step (2), the concentrate of the titanium hydroxide agglomerate is separated, and then the titanium hydroxide agglomerate is separated. (7) comprising a step (3A) of bringing the concentrate into contact with hydrochloric acid to acid-treat the aggregate of titanium hydroxide to obtain an acid-treated product of the aggregate of titanium hydroxide; A method for recovering the titanium component of;
(9) In the step (3A), a concentrate of the titanium hydroxide agglomerate is obtained by allowing the agglomerate of the titanium hydroxide produced by performing the step (2) to settle (8 ) recovery method for the titanium component;
(10) In the step (3A), after the step (2) is performed to precipitate the titanium hydroxide aggregate, the precipitate of the titanium hydroxide aggregate is separated, and then the titanium hydroxide is Dehydration treatment is performed to remove the liquid phase from the sediment of the aggregates of ( 8) the method for recovering the titanium component;
(11) After the step (2) is performed to precipitate the titanium hydroxide agglomerate, the precipitate of the titanium hydroxide agglomerate is brought into contact with hydrochloric acid to acidify the titanium hydroxide agglomerate. The method for producing titanium oxide according to (7), which comprises the step (3B) of obtaining an acid-treated aggregate of titanium hydroxide by treating the aggregate;
(12) The oxidation according to any one of (7) to (11), characterized by including a washing step of washing the acid-treated aggregate of titanium hydroxide with washing water of 6.0 or more and 9.0 or less. a method for producing titanium;
(13) Titanium hydroxide recovered by the method for recovering a titanium component according to any one of (1) to (6) or titanium oxide obtained by the method for producing titanium oxide according to any one of (7) to (12) as a raw material A method for producing an alkali metal titanate characterized by using as;
It provides

According to the present invention, a method for recovering a titanium component from a waste liquid containing a titanium compound, preferably a waste liquid containing a titanium compound generated during the preparation of a solid catalyst component for olefin polymerization or a catalyst for olefin polymerization, or A method for recovering a recovered titanium component or a titanium component having a low calcium content in titanium oxide or a method for producing titanium oxide even when calcium hydroxide or calcium oxide is used as a neutralizing agent in a method for producing titanium oxide can be provided.

1 is a flow diagram of an example of a method for recovering a titanium component according to the present invention; FIG. 1 is a flow diagram of an example of a method for recovering a titanium component according to the first embodiment of the present invention; FIG. FIG. 2 is a flow diagram of an example of a method for recovering a titanium component according to the first embodiment of the present invention, in which a washing step is performed; FIG. 4 is a flow diagram of another embodiment in which a cleaning step is performed in the method for recovering a titanium component according to the first embodiment of the present invention. FIG. 2 is a flow diagram of an example of a method for recovering a titanium component according to the second embodiment of the present invention. FIG. 4 is a flow diagram of an example of a method for recovering a titanium component according to the second embodiment of the present invention, in which a washing step is performed. FIG. 4 is a flow chart of another embodiment in which a cleaning step is performed in the method for recovering the titanium component according to the second embodiment of the present invention. 1 is a scanning electron micrograph of potassium titanate obtained in Example 1. FIG. 1 is a scanning electron micrograph of commercially available potassium titanate analyzed for comparison in Example 1. FIG. 4 is a scanning electron micrograph of potassium titanate obtained in Example 2. FIG. 2 is a scanning electron micrograph of commercially available potassium titanate analyzed for comparison in Example 2. FIG.

First, the method for recovering the titanium component of the present invention will be described.
A method for recovering a titanium component of the present invention is a method for recovering a titanium component from a waste liquid containing a titanium compound, comprising:
a step (1) of contacting the waste liquid containing the titanium compound with water to hydrolyze the titanium compound;
The hydrolyzed treatment liquid is subjected to primary neutralization treatment by adding calcium hydroxide or calcium oxide as a neutralizing agent so that the pH becomes 1.5 or more and less than 2.5, and then the primary neutralization. The treated solution is subjected to secondary neutralization treatment by adding calcium hydroxide or calcium oxide as a neutralizing agent so that the pH becomes 6.5 or more and 7.5 or less, and then titanium hydroxide is aggregated. a step (2) of obtaining an aggregate of titanium hydroxide by performing an aggregation treatment to
a step (3), after the step (2), of subjecting the aggregates of titanium hydroxide to acid treatment by contacting the aggregates of titanium hydroxide with hydrochloric acid to obtain an acid-treated product of the aggregates of titanium hydroxide;
having
characterized by

A method for recovering a titanium component according to the present invention will be described with reference to FIG. Here, a form in which calcium hydroxide is applied as a neutralizing agent will be described as an example. effect is obtained. FIG. 1 is a flow diagram of an embodiment of the method for recovering a titanium component of the present invention. In FIG. 1, a waste liquid 10 containing a titanium compound is transferred to a water receiving tank 1, water 11 is supplied into the water receiving tank 1, and the water 11 is mixed with the waste liquid 10 containing a titanium compound for hydrolysis treatment. Apply. Next, the hydrolyzed treated liquid is transferred to the primary neutralization tank 2, the calcium hydroxide suspension 12 is supplied to the primary neutralization tank 2, and the treated liquid in the primary neutralization tank 2 is A primary neutralization treatment is performed so that the pH of is 1.5 or more and less than 2.5. Next, the treated liquid subjected to the primary neutralization treatment is transferred to the secondary neutralization treatment tank 3, the calcium hydroxide suspension 13 is supplied to the secondary neutralization treatment tank 3, and the secondary neutralization treatment tank is A secondary neutralization treatment is performed so that the pH of the treatment liquid in 3 becomes 6.5 or more and 7.5 or less. Next, the treated liquid subjected to the secondary neutralization treatment is transferred to the flocculation tank 4, and a flocculating agent is added to the flocculation tank 4 to flocculate titanium hydroxide, thereby forming aggregates 19 of titanium hydroxide. give rise to Then, after the titanium hydroxide aggregates 19 are generated, the obtained titanium hydroxide aggregates 19 are brought into contact with hydrochloric acid 14 to acid-treat the titanium hydroxide aggregates 19 to remove the titanium hydroxide. An acid-treated aggregate 20 is obtained.

In the method for recovering a titanium component of the present invention, the object to be subjected to the method for recovering a titanium component is waste liquid containing a titanium compound, and is not particularly limited as long as it contains a titanium compound. As the waste liquid containing a titanium compound, "a waste liquid containing titanium" generated during preparation of a solid catalyst component for olefin polymerization or a catalyst for olefin polymerization is preferable.

In the method for recovering a titanium component of the present invention, when the waste liquid containing a titanium compound is a waste liquid containing titanium generated during the preparation of a solid catalyst component for olefin polymerization or a catalyst for olefin polymerization, it is suitable for olefin polymerization. The solid catalyst component or catalyst for olefin polymerization is not particularly limited as long as it is a solid catalyst component or catalyst containing a titanium component that is used for the polymerization of olefins. , Postmetallocene, catalysts such as solid titanium catalysts for polyethylene terephthalate production, and one or more selected from solid catalyst components constituting these catalysts. Among them, Ziegler-Natta catalysts used for polyolefin production , metallocene catalysts, post-metallocene catalysts, and solid catalyst components constituting these catalysts are preferable, and Ziegler-Natta catalysts or solid catalyst components constituting Ziegler-Natta catalysts are more preferable.

The Ziegler-Natta catalyst or the solid catalyst component constituting the Ziegler-Natta catalyst includes, among the above, a magnesium compound, a titanium compound, a halogen compound, and, if necessary, an electron-donating compound. is preferred.

As the magnesium compound used for the preparation of the above-mentioned solid catalyst component for polymerization of olefins, it is preferable to use a magnesium compound containing halogen or a magnesium compound which can be converted into a halogen-containing magnesium compound by contact reaction with a halogen-containing compound.
Examples of such magnesium compounds include one or more selected from magnesium dihalides such as magnesium chloride, dialkylmagnesium such as alkoxymagnesium halides, dialkoxymagnesium such as alkylmagnesium halides and diethoxymagnesium, and magnesium chloride. Or diethoxymagnesium is preferred.

As the titanium compound related to the method for recovering the titanium component of the present invention, for example, the following general formula (1):
Ti(OR)Nx4 _{-N (} 1)
(In the formula, R is a hydrocarbon group, X is a halogen atom, and when there are multiple Xs, each X may be the same or different, and N is an integer of 0 to 4. ) and titanium compounds represented by

In the titanium compound represented by the general formula (1), R is preferably a hydrocarbon group having 1 to 10 carbon atoms, more preferably a hydrocarbon group having 1 to 6 carbon atoms. ∼4 hydrocarbon groups are more preferred.

Specific examples of the titanium compound represented by the general formula (1) include titanium tetrahalides such as titanium tetrachloride, titanium tetrafluoride, titanium tetrabromide, titanium tetraiodide, methoxytitanium trichloride, ethoxy Alkoxytitanium trihalides such as titanium trichloride, propoxytitanium trichloride and N-butoxytitanium trichloride, dialkoxytitanium dihalides such as dimethoxytitanium dichloride, diethoxytitanium dichloride, dipropoxytitanium dichloride and di-N-butoxytitanium dichloride , tetraalkoxytitanium such as alkoxytitanium halide such as trimethoxytitanium chloride, triethoxytitanium chloride, tripropoxytitanium chloride, tri-N-butoxytitanium chloride and other trialkoxytitanium halides.

Among the above titanium compounds, halogen-containing titanium compounds are preferred, titanium tetrahalides selected from titanium tetrachloride, titanium tetrafluoride, titanium tetrabromide, titanium tetraiodide and the like are more preferred, and titanium tetrachloride is even more preferred.
The titanium compound may be diluted with a hydrocarbon compound, a halogenated hydrocarbon compound, or the like.

The electron-donating compound used for preparing the solid catalyst component for olefin polymerization is not particularly limited, but alcohols, phenols, ketones, aldehydes, carboxylic acids, acid halides, organic acids or inorganic acids. One or more selected from esters, ethers, acid amides, acid anhydrides, ammonia, amines, nitriles, isocyanates, nitrogen-containing cyclic compounds, oxygen-containing cyclic compounds, organosilicon compounds, and the like.

In the method for recovering the titanium component of the present invention, the waste liquid containing the titanium compound is used in the preparation process of the solid catalyst component for olefin polymerization. , hexane, heptane, octane, nonane, decane, dodecane, kerosene, cyclopentane, cyclohexane, methylcyclopentane, methylcyclohexane, ethylcyclohexane, 1,2-diethylcyclohexane, methylcyclohexene, decalin, saturated hydrocarbon compounds such as mineral oil , benzene, toluene, xylene, ethylbenzene and other aromatic hydrocarbon compounds, ortho-dichlorobenzene, methylene chloride, 1,2-dichlorobenzene, carbon tetrachloride, dichloroethane, ethylene chloride, chlorobenzene, dichloromethane and other halogenated hydrocarbons Compounds may contain one or more organic solvent components selected from aluminum compounds, silicon compounds and the like.

In the method for recovering a titanium component of the present invention, the waste liquid containing a titanium compound contains magnesium chloride or diethoxymagnesium as a magnesium compound, an alkoxytitanium halogen compound or a titanium halide compound as a titanium compound, and is electron-donating. Those containing compounds and organic solvent components are preferred.

In the method for recovering a titanium component of the present invention, the waste liquid containing titanium compounds contains titanium compounds produced by various reactions and the like. The waste liquid containing a titanium compound is preferably a waste liquid generated during preparation of a solid catalyst component for olefin polymerization or a catalyst for olefin polymerization. It includes other titanium compounds newly generated by reactions in the preparation process. In the method for recovering a titanium component of the present invention, the waste liquid containing a titanium compound preferably contains 0.01 to 35.0% by mass, more preferably 0.05 to 10.0% by mass, of the titanium compound. More preferably, it contains 0.10 to 5.0% by mass.

A method for recovering a titanium component according to the present invention includes a step (1) of contacting a waste liquid containing a titanium compound with water to hydrolyze the titanium compound. In the step (1), the method of hydrolysis is not particularly limited, and examples thereof include a method of bringing the wastewater into contact with separately injected water in a water receiving tank.

In step (1), when the titanium compound is a titanium halide, the titanium compound is hydrolyzed by contacting the effluent containing the titanium compound with water to produce hydrogen halide and titanium hydroxide. .

In the hydrolysis treatment according to step (1), the pH of the mixture of the titanium compound-containing waste liquid and water is preferably 0.5 or more and 2.0 or less, more preferably 0.7 or more and 1.5 or less. It is more preferable that it is about 1.0. When the pH of the mixed liquid of the waste liquid containing the titanium compound and water is within the above range, the titanium hydroxide produced in the mixed liquid is less likely to precipitate, and the subsequent treatment can be performed smoothly.

In the step (1), the amount of water to be brought into contact with the titanium compound-containing waste liquid is preferably 3 to 10 m ³ , more preferably 4 to 7 m ³ per 1 m ³ of the titanium compound-containing waste liquid. , 5 to 6 m ³ .

In step (1), the temperature during the hydrolysis treatment is not particularly limited, but is preferably 10 to 90°C, more preferably 20 to 70°C, and even more preferably 30 to 60°C. .

In step (1), the contact time between the waste liquid containing the titanium compound and water is preferably 30 to 60 minutes, more preferably 35 to 55 minutes, and further preferably 40 to 50 minutes. preferable.

In the step (2) of the method for recovering a titanium component of the present invention, the wastewater that has been hydrolyzed in the step (1) is subjected to primary neutralization treatment, then secondary neutralization treatment, and then 2) is a step of performing an agglomeration treatment for aggregating titanium hydroxide to obtain an agglomerate of titanium hydroxide.

In the step (2), first, a primary neutralization treatment in which calcium hydroxide or calcium oxide is added to the treated solution hydrolyzed in the step (1) so that the pH becomes 1.5 or more and less than 2.5. apply.

In the primary neutralization treatment, the pH of the treatment liquid subjected to the hydrolysis treatment in step (1) is 1.5 or more and less than 2.5, preferably 1.8 or more and 2.3 or less. Calcium hydroxide or calcium oxide is added so that the pH becomes 1.8 or more and 2.2 or less. When the pH in the primary neutralization treatment is within the above range, aggregation and sedimentation are likely to occur, making it easy to recover a high-purity titanium component from the titanium compound-containing waste liquid. On the other hand, if the pH during the primary neutralization treatment is less than 1.5, smooth neutralization treatment becomes difficult, and if the pH is 2.5 or more, gel-like titanium hydroxide is produced, Sedimentation and filterability are reduced.

The neutralizing agent used in the primary neutralization treatment is calcium hydroxide or calcium oxide. By using calcium hydroxide or calcium oxide as a neutralizing agent in the primary neutralization treatment, the cost of the neutralizing agent can be suppressed, and the sedimentation and filterability of the titanium compound obtained by neutralization are improved. has the advantage of On the other hand, when the neutralizing agent used in the primary neutralization treatment is, for example, sodium hydroxide or potassium hydroxide, the cost of the neutralizing agent increases, and the sedimentation and filterability of the titanium compound obtained by neutralization deteriorate. deteriorate and become industrially disadvantageous.

In the primary neutralization treatment, a suspension of calcium hydroxide or calcium oxide dispersed in water is brought into contact with a hydrolyzed treatment liquid. The content of calcium hydroxide or calcium oxide in the suspension is appropriately selected according to the pH setting value of the aqueous phase in the primary neutralization treatment, and is preferably 10 to 300 g/L. When the content of calcium hydroxide or calcium oxide in the suspension is within the above range, the pH of the hydrolyzed waste liquid can be easily controlled within the desired range. On the other hand, if the content of calcium hydroxide in the suspension exceeds the above range, it will be difficult to control the pH of the hydrolyzed waste liquid, and if it is less than the above range, smooth neutralization will occur. difficult to perform.

The temperature during the primary neutralization treatment is not particularly limited, but is preferably 10° C. or higher.

In the primary neutralization treatment, the contact time between the hydrolyzed treatment solution and calcium hydroxide or calcium oxide is not particularly limited, but is usually about 60 to 120 minutes.

In the step (2), the primary neutralization treatment is performed by contacting calcium hydroxide or calcium oxide in a neutralization tank (primary neutralization treatment tank) with respect to the hydrolyzed treatment liquid. It is preferable to carry out, and the primary neutralization treatment tank may be one tank, or a plurality of tanks may be connected.

In step (2), secondary neutralization is then performed by adding calcium hydroxide or calcium oxide to the treated liquid that has been subjected to primary neutralization so that the pH becomes 6.5 or more and 7.5 or less.

During the secondary neutralization treatment in step (2), calcium hydroxide or calcium oxide is added to the treatment liquid that has been subjected to the primary neutralization treatment so that the pH becomes 6.5 or more and 7.5 or less. Then, during the secondary neutralization treatment in step (2), calcium hydroxide or calcium oxide is added to the treatment liquid subjected to the primary neutralization treatment so that the pH becomes 6.5 or more and 7.5 or less. Preferably, calcium hydroxide or calcium oxide is added so that the pH is 6.4 or more and 7.5 or less, and calcium hydroxide or calcium oxide is added so that the pH is 6.3 or more and 7.5 or less. More preferably, calcium is added.

When the pH in the secondary neutralization treatment is within the above range, the calcium content in the aggregates of titanium hydroxide obtained through the aggregation treatment is reduced, and aggregation and sedimentation are likely to occur, resulting in titanium compounds. It becomes easy to recover the titanium component with high purity from the contained waste liquid. On the other hand, if the pH during the secondary neutralization treatment is less than the above range, the precipitation of titanium hydroxide becomes difficult. Too much content.

A neutralizing agent used in the secondary neutralization treatment is calcium hydroxide or calcium oxide. By using calcium hydroxide or calcium oxide as a neutralizing agent in the secondary neutralization treatment, the cost of the neutralizing agent can be suppressed, and the sedimentation and filterability of the neutralized titanium compound are improved. have the advantage of On the other hand, if the neutralizing agent used in the secondary neutralization treatment is, for example, sodium hydroxide or potassium hydroxide, the cost of the neutralizing agent increases, and the sedimentation and filterability of the titanium compound that can be neutralized. becomes worse and is industrially disadvantageous.

In the secondary neutralization treatment, a suspension of calcium hydroxide or calcium oxide dispersed in water is brought into contact with the treatment liquid that has undergone the primary neutralization treatment. The content of calcium hydroxide or calcium oxide in the suspension is appropriately selected according to the pH setting value of the aqueous phase in the secondary neutralization treatment, and is preferably 10 to 300 g/L. When the content of calcium hydroxide or calcium oxide in the suspension is within the above range, it is easy to control the pH of the treatment liquid that has undergone the primary neutralization treatment within the desired range. On the other hand, if the content of calcium hydroxide or calcium oxide in the suspension exceeds the above range, it becomes difficult to control the pH during the primary neutralization treatment. Neutralization becomes difficult.

The temperature during the secondary neutralization treatment is not particularly limited, but is preferably 10° C. or higher.

In the secondary neutralization treatment, the contact time between the treatment liquid subjected to the primary neutralization treatment and calcium hydroxide or calcium oxide is not particularly limited, but is usually about 60 to 120 minutes.

In the step (2), as a method of performing the secondary neutralization treatment, calcium hydroxide or calcium oxide is added to the treated liquid that has undergone the primary neutralization treatment in a neutralization tank (secondary neutralization treatment tank). It is preferable to carry out by contact, and the secondary neutralization treatment tank may be one tank, or a plurality of tanks may be connected.

Moreover, it is preferable that calcium hydroxide is not contained in the treatment liquid after the secondary neutralization treatment. The content of calcium hydroxide in the treated liquid after the secondary neutralization treatment is adjusted by the amount of neutralizing agent added in the secondary neutralization treatment, the pH setting value in the secondary neutralization treatment, and the like. be.

In the step (2), aggregating treatment is then performed to aggregate titanium hydroxide in the treatment liquid that has undergone the secondary neutralization treatment. The flocculation treatment may be chemical treatment using a flocculant such as an anionic polymer flocculant, or mechanical treatment (dehydration) using various devices such as a filter press, liquid cyclone, and centrifugal separation processing) may be applied. The method of coagulation treatment may be appropriately selected according to the components and concentration of the waste liquid. By applying the flocculation treatment, it is possible to shorten the time required for the filtration treatment in the post-process.

In the step (2), the aggregation of titanium hydroxide is preferably carried out in the aggregation tank by feeding the treatment liquid that has undergone the secondary neutralization treatment into the same tank. Aggregates of titanium hydroxide are produced by carrying out the aggregating treatment.

In step (2), by aggregating titanium hydroxide, agglomerates of titanium hydroxide are generated. The latter step may be performed after part or all of the liquid phase is separated, or the latter step may be performed without separating the liquid phase from the agglomeration treatment liquid containing the resulting titanium hydroxide aggregates. may be performed.

In the step (2) or a step subsequent to the step (2), the aqueous phase separated from the aggregation treatment liquid containing the aggregates of titanium hydroxide is adjusted to have a neutral acidity (pH 6.5 to 7.5). After that, it is preferable to appropriately treat the waste liquid.

For example, in the method for recovering a titanium component of the present invention, after step (2) is performed, the resulting titanium hydroxide aggregates are allowed to settle in a sedimentation tank, and the titanium hydroxide aggregates in the sedimentation tank are By withdrawing the sediment, the titanium hydroxide agglomerate is separated in the form of a sediment of titanium hydroxide agglomerate. This sediment of titanium hydroxide aggregates contains a liquid phase derived from the treatment up to that point. may be provided after removing the liquid phase, or may be provided without removing the liquid phase in the sediment of titanium hydroxide aggregates.

In the method for recovering a titanium component of the present invention, in the treatment step subsequent to step (2), the aggregate of titanium hydroxide is subjected to an acid treatment in which hydrochloric acid is brought into contact. In the method for recovering a titanium component of the present invention, the timing of acid treatment is not particularly limited as long as it is after the step (2). In the method for recovering the titanium component of the present invention, the calcium content in the titanium hydroxide aggregate can be reduced by bringing the titanium hydroxide aggregate into contact with hydrochloric acid.

In the acid treatment according to the method for recovering the titanium component of the present invention, the aggregates of titanium hydroxide obtained by the step (2) are brought into contact with hydrochloric acid. At this time, the pH of the liquid phase becomes 5.9 or less. contact with hydrochloric acid. When the pH of the liquid phase during the acid treatment is within the above range, the calcium content in the aggregates of titanium hydroxide can be reduced. On the other hand, when the pH of the liquid phase during the acid treatment exceeds the above range, it becomes difficult to obtain the effect of reducing the calcium content in the aggregates of titanium hydroxide. The upper limit of the pH of the liquid phase during acid treatment is preferably 5.7 or less, more preferably 5.5 or less, and still more preferably 5.3 or less. The lower limit of the pH of the liquid phase during acid treatment is preferably 2.0 or higher, more preferably 3.0 or higher.

The acid used for acid treatment is hydrochloric acid. Hydrogen chloride is volatilized and removed from the product during drying or oxidation of the titanium hydroxide agglomerate after the acid treatment, so the chlorine content derived from the hydrochloric acid used for the acid treatment is removed. , is difficult to remain in the product.

The concentration of hydrochloric acid used for the acid treatment is not particularly limited, but is preferably 1.0 to 8.5 mol/L, preferably 1.5 to 7.0 mol/L, and 2.7 to 5.5 mol/L. 5 mol/L is more preferred. When the concentration of hydrochloric acid used for the acid treatment is within the above range, the pH of the liquid phase during the acid treatment can be easily controlled within the desired range. If the concentration of hydrochloric acid used for the acid treatment exceeds the above range, it becomes difficult to control the pH of the liquid phase during the acid treatment, and if it is below the above range, it becomes difficult to carry out the acid treatment smoothly.

The temperature during the acid treatment is not particularly limited, but is preferably 10 to 50°C, more preferably 15 to 45°C, even more preferably 20 to 40°C.

In the acid treatment, the contact time between the titanium hydroxide aggregate obtained by the step (2) and hydrochloric acid is preferably 60 to 120 minutes, more preferably 60 to 100 minutes, more preferably 60 to 80 minutes. Minutes is more preferred.

In the method for recovering the titanium component of the present invention, the titanium hydroxide produced by acid treatment is Ti(OH) ₄ . That is, in the method for recovering the titanium component of the present invention, the titanium component is recovered from the waste liquid containing the titanium compound in the form of aggregates of titanium hydroxide. After drying and oxidation, the recovered aggregate of titanium hydroxide (acid-treated product) is converted to titanium oxide and used as a raw material for producing various titanium compounds.

In the method for recovering a titanium component of the present invention, after hydrolysis treatment of wastewater containing a titanium compound, using calcium hydroxide as a neutralizing agent, primary neutralization treatment and secondary neutralization treatment are performed at a specific pH, The calcium content in the titanium hydroxide agglomerate obtained by the acid treatment can be reduced by subjecting the titanium hydroxide agglomerate obtained by successive agglomeration treatments to an acid treatment in which hydrochloric acid is brought into contact with the agglomerate. From this, titanium hydroxide having a low calcium content can be recovered in high yield. In the method for recovering the titanium component of the present invention, the titanium hydroxide aggregates are acid-treated to dissolve and remove poorly water-soluble unreacted substances such as calcium hydroxide remaining in the titanium hydroxide aggregates. , the calcium content in the aggregates of titanium hydroxide can be reduced. From the above, it is considered that the titanium component recovery method of the present invention can recover titanium hydroxide having a low calcium content.

In the method for recovering the titanium component of the present invention, the method of performing the acid treatment is not particularly limited and may be appropriately selected. Also, the method of acid treatment may be any method as long as it brings the aggregate of titanium hydroxide into contact with hydrochloric acid. The method for recovering the titanium component of the present invention includes the following modes.

In the method for recovering a titanium component according to the first aspect of the present invention, after the step (2) is performed to obtain a concentrate of titanium hydroxide aggregates, the concentrate of titanium hydroxide aggregates is separated, and then and a step (3A) of contacting a concentrate of titanium hydroxide aggregates with hydrochloric acid to acid-treat the titanium hydroxide aggregates to obtain an acid-treated product of the titanium hydroxide aggregates. be.

That is, a method for recovering a titanium component according to a first aspect of the present invention is a method for recovering a titanium component from a waste liquid containing a titanium compound, comprising:
a step (1) of contacting the waste liquid containing the titanium compound with water to hydrolyze the titanium compound;
The treated water subjected to hydrolysis treatment is subjected to primary neutralization treatment by adding calcium hydroxide as a neutralizing agent so that the pH becomes 1.5 or more and less than 2.5, and then the primary neutralization treatment is performed. The treated solution is subjected to a secondary neutralization treatment by adding calcium hydroxide as a neutralizing agent so that the pH becomes 6.5 or more and 7.5 or less, and then a flocculation treatment to flocculate titanium hydroxide, a step (2) of obtaining an aggregate of titanium hydroxide;
After the step (2) is performed to obtain the resulting titanium hydroxide aggregate concentrate, the titanium hydroxide aggregate concentrate is separated, and then the titanium hydroxide aggregate concentrate is a step (3A) of bringing the aggregate of titanium hydroxide into contact with hydrochloric acid to acid-treat the aggregate of titanium hydroxide to obtain an acid-treated product of the aggregate of titanium hydroxide;
having
A method for recovering a titanium component characterized by In the method for recovering a titanium component according to the first aspect of the present invention, after producing aggregates of titanium hydroxide in step (2), a concentrate of aggregates of titanium hydroxide is separated from the aggregation treatment liquid, In this embodiment, the concentrate of titanium oxide aggregates is subjected to an acid treatment.

A method for recovering a titanium component according to the first embodiment of the present invention will be described with reference to FIG. FIG. 2 is a flow diagram of an example of a method for recovering a titanium component according to the first embodiment of the present invention. Here, too, an embodiment in which calcium hydroxide is applied as a neutralizing agent will be described as an example. effect is obtained. In FIG. 2, a waste liquid 10 containing a titanium compound is transferred to a water receiving tank 1, water 11 is supplied into the water receiving tank 1, and the water 11 and the waste liquid 10 containing a titanium compound are mixed to perform a hydrolysis treatment. Apply. Next, the hydrolyzed treated liquid is transferred to the primary neutralization tank 2, the calcium hydroxide suspension 12 is supplied to the primary neutralization tank 2, and the treated liquid in the primary neutralization tank 2 is A primary neutralization treatment is performed so that the pH of is 1.5 or more and less than 2.5. Next, the treated liquid subjected to the primary neutralization treatment is transferred to the secondary neutralization treatment tank 3, the calcium hydroxide suspension 13 is supplied to the secondary neutralization treatment tank 3, and the secondary neutralization treatment tank is A secondary neutralization treatment is performed so that the pH of the treatment liquid in 3 becomes 6.5 or more and 7.5 or less. Next, the treated liquid subjected to the secondary neutralization treatment is transferred to the flocculation tank 4, and a flocculating agent is added to the flocculation tank 4 to flocculate the titanium hydroxide, thereby producing an agglomerate of titanium hydroxide. Let Next, the coagulation treatment liquid containing the resulting titanium hydroxide aggregates is transferred to the sedimentation tank 5, where the titanium hydroxide aggregates are allowed to settle. The precipitate of titanium hydroxide agglomerates is withdrawn. Next, the sediment of titanium hydroxide agglomerates extracted from the sedimentation tank 5 is transferred to the sediment storage tank 6 . Next, the precipitate of titanium hydroxide aggregates is filtered using the filter press device 7 to remove the liquid phase from the precipitate of titanium hydroxide aggregates, and the titanium hydroxide aggregates are separated by filtration. , to obtain a presscake of titanium hydroxide agglomerates. Next, the press cake of titanium hydroxide aggregates is transferred to an acid treatment tank 8, hydrochloric acid 14 is supplied to the acid treatment tank 8, and the titanium hydroxide aggregates and hydrochloric acid 14 are mixed and acid treated. . Next, the acid-treated titanium hydroxide agglomerate is filtered using a filter press device 9 to remove the liquid phase from the acid-treated titanium hydroxide agglomerate. The treated material is filtered to obtain a press cake 21 of an acid-treated aggregate of titanium hydroxide.

A method for recovering a titanium component according to the first embodiment of the present invention includes steps (1), (2), and (3A). The steps (1) and (2), the waste water to be used, the treatment, the treatment method, and the like in the method for recovering a titanium component according to the first embodiment of the present invention are common to those of the method for recovering a titanium compound of the present invention, and the details thereof are described below. are as described in the explanation of the method for recovering the titanium component of the present invention.

In the step (3A) relating to the method for recovering a titanium component according to the first embodiment of the present invention, after the step (2) is carried out to obtain a concentrate of titanium hydroxide agglomerates, the obtained agglomerates of titanium hydroxide are A concentrate of substances is separated from the flocculant treatment liquid.

In the step (3A), the method for obtaining the concentrate of the titanium hydroxide aggregates from the aggregating treatment liquid containing the titanium hydroxide aggregates after performing the step (2) is not particularly limited. For example, first, (i) the aggregating treatment liquid containing titanium hydroxide agglomerate after step (2) is transferred to a sedimentation tank, and the titanium hydroxide agglomerate is allowed to settle in the sedimentation tank. Next, (ii) extracting the precipitate of titanium hydroxide aggregates from the bottom or bottom of the sedimentation tank, separating the precipitate of titanium hydroxide aggregates from the coagulation treatment liquid, The titanium agglomerate sediment is transferred to a sediment storage tank to obtain a titanium hydroxide agglomerate sediment, ie, a titanium hydroxide agglomerate concentrate.

Further, in the step (3A), other methods for obtaining a concentrate of titanium hydroxide agglomerates from the aggregating treatment liquid containing the agglomerates of titanium hydroxide after performing the step (2) include, for example, , the aggregating treatment liquid containing titanium hydroxide agglomerates after the step (2) is treated with a liquid cyclone, a screw decanter, or the like to separate the water phase from the aggregating treatment liquid to obtain titanium hydroxide agglomerates. and a method of obtaining a concentrate of

Further, in the step (3A), as a method for obtaining a concentrate of titanium hydroxide aggregates from the aggregation treatment liquid containing the titanium hydroxide aggregates after the step (2) is performed, first, the step (2 ) to settle the titanium hydroxide agglomerate, the sediment of the titanium hydroxide agglomerate is separated from the aggregating treatment liquid, and then the liquid phase is removed from the sediment of the titanium hydroxide agglomerate. dehydration treatment to obtain a dehydrated titanium hydroxide aggregate, that is, a method for obtaining a dehydrated titanium hydroxide aggregate, that is, a concentrate of the titanium hydroxide aggregate. Examples of the dehydration method include a method of filtering using a solid-liquid separation device such as a filter press device, a centrifugal separator, or a liquid cyclone device.

In step (3A), the concentrated titanium hydroxide aggregate is then brought into contact with hydrochloric acid to acid-treat the titanium hydroxide aggregate.

In the acid treatment in step (3A), the dehydrated titanium hydroxide aggregate is brought into contact with hydrochloric acid. At this time, the pH of the liquid phase is 5.9 or less, preferably 2.0 or more and 5.5. Thereafter, contact is made with hydrochloric acid so as to more preferably be 3.5 or more and 5.0 or less. When the pH of the liquid phase during the acid treatment is within the above range, the calcium content in the aggregates of titanium hydroxide can be reduced. On the other hand, if the pH of the liquid phase during the acid treatment exceeds 5.9, it becomes difficult to obtain the effect of reducing the calcium content in the aggregates of titanium hydroxide.

The acid used for the acid treatment in step (3A) is hydrochloric acid. Hydrogen chloride is volatilized and removed from the product during drying or oxidation of the titanium hydroxide agglomerate after acid treatment, so the chlorine content derived from hydrochloric acid is removed in the product. difficult to remain.

The concentration of hydrochloric acid used for the acid treatment in step (3A) is not particularly limited, but is preferably 1.0 to 8.5 mol/L, preferably 1.5 to 7.0 mol/L. .7 to 5.5 mol/L is more preferable. When the concentration of hydrochloric acid used for the acid treatment is within the above range, the pH of the liquid phase during the acid treatment can be easily controlled within the desired range. If the concentration of hydrochloric acid used for the acid treatment exceeds the above range, it becomes difficult to control the pH of the liquid phase during the acid treatment, and if it is below the above range, it becomes difficult to carry out the acid treatment smoothly.

The temperature during the acid treatment in step (3A) is not particularly limited, but is preferably 10 to 50°C, more preferably 15 to 45°C, and even more preferably 20 to 40°C.

In the acid treatment in step (3A), the contact time between the dehydrated titanium hydroxide aggregate and hydrochloric acid is preferably 60 to 120 minutes, more preferably 60 to 100 minutes, and more preferably 60 minutes. More preferably ∼80 minutes.

In the step (3A), the acid treatment is preferably carried out by bringing the dehydrated aggregate of titanium hydroxide into contact with hydrochloric acid in an acid treatment tank.

In the step (3A), after the acid treatment, a liquid phase is removed from the acid-treated titanium hydroxide aggregates using a solid-liquid separator to obtain an acid-treated titanium hydroxide aggregates. and further dried at 60 to 200° C. to obtain an acid-treated aggregate of titanium hydroxide. Water and hydrogen chloride are removed from the acid-treated titanium hydroxide agglomerate by removing the liquid phase from the acid-treated titanium hydroxide agglomerate and drying the acid-treated titanium hydroxide agglomerate. is obtained.

In the method for recovering a titanium component according to the first aspect of the present invention, the titanium hydroxide obtained by carrying out the step (3A) is Ti(OH) ₄ . That is, in the method for recovering the titanium component of the present invention, the titanium component is recovered from the waste liquid containing the titanium compound in the form of aggregates of titanium hydroxide. After drying and oxidation, the recovered aggregate of titanium hydroxide (acid-treated product) is converted to titanium oxide and used as a raw material for producing various titanium compounds.

In the method for recovering a titanium component according to the first aspect of the present invention, after hydrolysis treatment of wastewater containing a titanium compound, calcium hydroxide or calcium oxide is used as a neutralizing agent to perform primary neutralization at a specific pH. Treatment, secondary neutralization treatment, and flocculation treatment are sequentially performed to generate aggregates of titanium hydroxide, then the aqueous phase is separated, and the obtained concentrate of titanium hydroxide aggregates is brought into contact with hydrochloric acid. Since the calcium content in the aggregates of titanium hydroxide obtained by the acid treatment can be reduced by the acid treatment, titanium hydroxide with a low calcium content can be recovered. In the method for recovering a titanium component according to the first aspect of the present invention, the concentrate of titanium hydroxide aggregates produced in the step (2) is acid-treated, thereby acid-treating the titanium hydroxide aggregates. By carrying out the treatment, the hardly water-soluble unreacted substances such as calcium hydroxide remaining in the titanium hydroxide aggregates are dissolved, so that the calcium content in the titanium hydroxide aggregates can be reduced. From the above, it is considered that the titanium component recovery method of the first embodiment of the present invention can recover titanium hydroxide having a low calcium content.

The method for recovering a titanium component according to the first aspect of the present invention comprises the steps (1), (2) and (3A), and in addition to the step (3A), an acid-treated aggregate of titanium hydroxide obtained by performing the step (3A). can be washed with washing water having a pH of 6.0 or more and 9.0 or less. In the washing step, washing is carried out by bringing washing water into contact with the acid-treated titanium hydroxide agglomerate obtained in step (3A). The contact method is not particularly limited, and includes, for example, the following methods.

FIG. 3 is a flow diagram showing an example of a mode in which a cleaning step is performed in the method for recovering a titanium component according to the first mode of the present invention. Here, too, an embodiment in which calcium hydroxide is applied as a neutralizing agent will be described as an example. effect is obtained. In FIG. 3, a waste liquid 10 containing a titanium compound is transferred to a water receiving tank 1, water 11 is supplied into the water receiving tank 1, and the water 11 and the waste liquid 10 containing a titanium compound are mixed to perform a hydrolysis treatment. Apply. Next, the hydrolyzed treated liquid is transferred to the primary neutralization tank 2, the calcium hydroxide suspension 12 is supplied to the primary neutralization tank 2, and the treated liquid in the primary neutralization tank 2 is A primary neutralization treatment is performed so that the pH of is 1.5 or more and less than 2.5. Next, the treated liquid subjected to the primary neutralization treatment is transferred to the secondary neutralization treatment tank 3, the calcium hydroxide suspension 13 is supplied to the secondary neutralization treatment tank 3, and the secondary neutralization treatment tank is A secondary neutralization treatment is performed so that the pH of the treatment liquid in 3 becomes 6.5 or more and 7.5 or less. Next, the treated liquid subjected to the secondary neutralization treatment is transferred to the flocculation tank 4, and a flocculating agent is added to the flocculation tank 4 to flocculate the titanium hydroxide, thereby producing an agglomerate of titanium hydroxide. Let Next, the coagulation treatment liquid containing the resulting titanium hydroxide aggregates is transferred to the sedimentation tank 5, where the titanium hydroxide aggregates are allowed to settle. The precipitate of titanium hydroxide agglomerates is withdrawn. Next, the sediment of titanium hydroxide agglomerates extracted from the sedimentation tank 5 is transferred to the sediment storage tank 6 . Next, the precipitate of titanium hydroxide aggregates is filtered using the filter press device 7 to remove the liquid phase from the precipitate of titanium hydroxide aggregates, and the titanium hydroxide aggregates are separated by filtration. , to obtain a presscake of titanium hydroxide agglomerates. Next, the press cake of titanium hydroxide aggregates is transferred to an acid treatment tank 8, hydrochloric acid 14 is supplied to the acid treatment tank 8, and the titanium hydroxide aggregates and hydrochloric acid 14 are mixed and acid treated. . Next, the acid-treated titanium hydroxide agglomerate is filtered using a filter press device 9 to remove the liquid phase from the acid-treated titanium hydroxide agglomerate. By filtering the treated product, a press cake of an acid-treated aggregate of titanium hydroxide is obtained. Next, the press cake of the acid-treated aggregate of titanium hydroxide is transferred to the cleaning tank 31, and the cleaning water 15 is supplied to the cleaning tank 31 to produce the acid-treated aggregate of titanium hydroxide and the cleaning water. 15 are mixed and washed. Next, the washed product of the acid-treated aggregate of titanium hydroxide is filtered using a filter press device 33 to remove the liquid phase from the washed product of the acid-treated aggregate of titanium hydroxide. By filtering the acid-treated titanium agglomerates, a press cake 22 of the acid-treated agglomerates of titanium hydroxide is obtained.

That is, in the first embodiment of the washing step, the acid-treated product of titanium hydroxide aggregate obtained by performing the step (3A) is subjected to a solid-liquid separation device such as a filter press device, a centrifugal separation device, or a liquid cyclone device. to separate the acid-treated aggregate of titanium hydroxide from the liquid phase to obtain a dehydrated product such as press cake, then remove the dehydrated product such as press cake from the solid-liquid separator, and then dehydrate. In this mode, washing is performed by bringing washing water into contact with the object to be treated.

In the washing step of the first embodiment, after contacting the acid-treated titanium hydroxide agglomerate with washing water, using a solid-liquid separation device such as a filter press device, a centrifugal separator, or a liquid cyclone device, The acid-treated aggregate of titanium hydroxide and the washing water are separated to obtain the acid-treated aggregate of titanium hydroxide.

FIG. 4 is a flow chart showing an example of another embodiment in which a cleaning step is performed in the method for recovering titanium components according to the first embodiment of the present invention. Here, a mode in which calcium hydroxide is applied as a neutralizing agent will be described as an example, but in the present invention, even if calcium oxide is applied, the same effect as when calcium hydroxide is applied can be obtained. . In FIG. 4, a waste liquid 10 containing a titanium compound is transferred to a water receiving tank 1, water 11 is supplied into the water receiving tank 1, and the water 11 and the waste liquid 10 containing a titanium compound are mixed to perform a hydrolysis treatment. Apply. Next, the hydrolyzed treated liquid is transferred to the primary neutralization tank 2, the calcium hydroxide suspension 12 is supplied to the primary neutralization tank 2, and the treated liquid in the primary neutralization tank 2 is A primary neutralization treatment is performed so that the pH of is 1.5 or more and less than 2.5. Next, the treated liquid subjected to the primary neutralization treatment is transferred to the secondary neutralization treatment tank 3, the calcium hydroxide suspension 13 is supplied to the secondary neutralization treatment tank 3, and the secondary neutralization treatment tank is A secondary neutralization treatment is performed so that the pH of the treatment liquid in 3 becomes 6.5 or more and 7.5 or less. Next, the treated liquid subjected to the secondary neutralization treatment is transferred to the flocculation tank 4, and a flocculating agent is added to the flocculation tank 4 to flocculate the titanium hydroxide, thereby producing an agglomerate of titanium hydroxide. Let Next, the coagulation treatment liquid containing the resulting titanium hydroxide aggregates is transferred to the sedimentation tank 5, where the titanium hydroxide aggregates are allowed to settle. The precipitate of titanium hydroxide agglomerates is withdrawn. Next, the sediment of titanium hydroxide agglomerates extracted from the sedimentation tank 5 is transferred to the sediment storage tank 6 . Next, the precipitate of titanium hydroxide aggregates is filtered using the filter press device 7 to remove the liquid phase from the precipitate of titanium hydroxide aggregates, and the titanium hydroxide aggregates are separated by filtration. , to obtain a presscake of titanium hydroxide agglomerates. Next, the press cake of titanium hydroxide aggregates is transferred to an acid treatment tank 8, hydrochloric acid 14 is supplied to the acid treatment tank 8, and the titanium hydroxide aggregates and hydrochloric acid 14 are mixed and acid treated. . Next, the acid-treated titanium hydroxide agglomerate is filtered using a filter press device 9 to remove the liquid phase from the acid-treated titanium hydroxide agglomerate. Washing is performed by supplying washing water 15 pressurized to 0.2 to 0.5 MPa to the filtered matter and contacting the filtered matter with the washing water 15 at high pressure to perform washing by penetrating washing, and acidifying the aggregates of titanium hydroxide. A press cake 23 of the processed material is obtained.

That is, in the second form of the washing step, the acid-treated product of the titanium hydroxide aggregates obtained by performing the step (3A) is filtered using a filter press to separate the titanium hydroxide aggregates from the liquid phase. Further, washing is performed by supplying washing water pressurized to 0.2 to 0.5 MPa to the filtered matter in the filter press device and contacting the filtered matter with the washing water at high pressure by penetrating washing. be.

The pH of the washing water used in the washing step may be any pH that allows washing without altering the properties of the titanium hydroxide, and is usually 6.0 or more and 9.0 or less. The washing water that can wash the titanium hydroxide without deteriorating its properties is not particularly limited. .

Although the temperature during washing is not particularly limited, it is preferably 10 to 50°C, more preferably 15 to 45°C, even more preferably 20 to 40°C.

After the washing step, a solid-liquid separator is used to separate the liquid phase from the washing treatment liquid containing the acid-treated titanium hydroxide aggregates after washing, and the titanium hydroxide aggregates are dehydrated. Then, the dehydrated product is dried at 60 to 200° C. to obtain an acid-treated aggregate of titanium hydroxide.

In the method for recovering a titanium component according to the first aspect of the present invention, when the waste liquid containing the titanium compound generated during the preparation of the solid catalyst component for olefin polymerization or the catalyst for olefin polymerization contains chlorine, By performing the washing step, the chlorine content in the aggregates of titanium hydroxide can be reduced.

In the method for recovering a titanium component according to the second aspect of the present invention, after the step (2) is performed to precipitate the titanium hydroxide aggregate, the precipitate of the titanium hydroxide aggregate is brought into contact with hydrochloric acid, This embodiment has a step (3B) of acid-treating the aggregates of titanium hydroxide to obtain an acid-treated product of the aggregates of titanium hydroxide.

That is, a method for recovering a titanium component according to a second aspect of the present invention is a method for recovering a titanium component from a waste liquid containing a titanium compound, comprising:
a step (1) of contacting the waste liquid containing the titanium compound with water to hydrolyze the titanium compound;
The hydrolyzed treatment liquid is subjected to primary neutralization treatment by adding calcium hydroxide or calcium oxide as a neutralizing agent so that the pH becomes 1.5 or more and less than 2.5, and then the primary neutralization. The treated solution is subjected to secondary neutralization treatment by adding calcium hydroxide or calcium oxide as a neutralizing agent so that the pH becomes 6.5 or more and 7.5 or less, and then titanium hydroxide is aggregated. a step (2) of obtaining an aggregate of titanium hydroxide by performing an aggregation treatment to
After the step (2) is carried out to precipitate the titanium hydroxide agglomerate, the sediment of the titanium hydroxide agglomerate is brought into contact with hydrochloric acid to acid-treat the titanium hydroxide agglomerate. a step (3B) of obtaining an acid-treated titanium oxide aggregate;
having
A method for recovering a titanium component characterized by In the method for recovering a titanium component according to the second aspect of the present invention, after producing aggregates of titanium hydroxide in the step (2), the sediment of the aggregates of titanium hydroxide is separated from the aggregation treatment liquid, In this mode, the sediment of titanium hydroxide aggregate is subjected to acid treatment without removing the liquid phase in the sediment of titanium oxide aggregate.

A method for recovering a titanium component according to the second embodiment of the present invention will be described with reference to FIG. FIG. 5 is a flow diagram of an example of a method for recovering a titanium component according to the second embodiment of the present invention. Here, too, an embodiment in which calcium hydroxide is applied as a neutralizing agent will be described as an example. effect is obtained. In FIG. 5, a waste liquid 10 containing a titanium compound is transferred to a water receiving tank 1, water 11 is supplied into the water receiving tank 1, and the water 11 and the waste liquid 10 containing a titanium compound are mixed to perform a hydrolysis treatment. Apply. Next, the hydrolyzed treated liquid is transferred to the primary neutralization tank 2, the calcium hydroxide suspension 12 is supplied to the primary neutralization tank 2, and the treated liquid in the primary neutralization tank 2 is A primary neutralization treatment is performed so that the pH of is 1.5 or more and less than 2.5. Next, the treated liquid subjected to the primary neutralization treatment is transferred to the secondary neutralization treatment tank 3, the calcium hydroxide suspension 13 is supplied to the secondary neutralization treatment tank 3, and the secondary neutralization treatment tank is A secondary neutralization treatment is performed so that the pH of the treatment liquid in 3 becomes 6.5 or more and 7.5 or less. Next, the treated liquid subjected to the secondary neutralization treatment is transferred to the flocculation tank 4, and a flocculating agent is added to the flocculation tank 4 to flocculate the titanium hydroxide, thereby producing an agglomerate of titanium hydroxide. Let Next, the coagulation treatment liquid containing the resulting titanium hydroxide aggregates is transferred to the sedimentation tank 5, where the titanium hydroxide aggregates are allowed to settle. The precipitate of titanium hydroxide agglomerates is withdrawn. Next, the precipitate of titanium hydroxide agglomerates extracted from the sedimentation tank 5 is transferred to an acid treatment tank 18, and hydrochloric acid 14 is supplied to the acid treatment tank 18 to remove the precipitate of titanium hydroxide agglomerates and hydrochloric acid. 14 are mixed and acid-treated. Next, the acid-treated titanium hydroxide agglomerate is filtered using the filter press device 7 to remove the liquid phase from the acid-treated titanium hydroxide agglomerate, and the titanium hydroxide agglomerate is acidified. By filtering the treated material, a press cake 24 of an acid-treated aggregate of titanium hydroxide is obtained.

A method for recovering a titanium component according to the first embodiment of the present invention includes steps (1), (2), and (3B). The steps (1) and (2), the waste water to be used, the treatment, the treatment method, etc. in the method for recovering a titanium component according to the second aspect of the present invention are the same as those of the method for recovering a titanium compound of the present invention. are as described in the explanation of the method for recovering the titanium component of the present invention.

In the step (3B) of the method for recovering a titanium component according to the second aspect of the present invention, the titanium hydroxide aggregates produced by the step (2) are allowed to settle, and then the resulting titanium hydroxide aggregates are precipitated. The substance is brought into contact with hydrochloric acid to acid-treat the aggregate of titanium hydroxide to obtain an acid-treated product of the aggregate of titanium hydroxide.

In step (3B), the method for obtaining a precipitate of titanium hydroxide aggregates from the aggregating treatment liquid containing titanium hydroxide aggregates after step (2) is not particularly limited. For example, first, (i) the aggregating treatment liquid containing titanium hydroxide agglomerate after step (2) is transferred to a sedimentation tank, and the titanium hydroxide agglomerate is allowed to settle in the sedimentation tank. Next, (ii) a method of extracting the precipitate of titanium hydroxide aggregates from the bottom or bottom of the sedimentation tank and transferring the precipitate of titanium hydroxide aggregates extracted from the sedimentation tank to an acid treatment tank. be done.

Further, in the step (3B), the method for obtaining the sediment of the titanium hydroxide aggregates from the aggregating treatment liquid containing the titanium hydroxide aggregates after the step (2) is performed includes the step (2). A method of obtaining a sediment of titanium hydroxide aggregates by treating the coagulation treatment liquid containing titanium hydroxide aggregates after the treatment with a liquid cyclone, a screw decanter, or the like to separate the aqueous phase from the aggregation treatment liquid. is mentioned.

In the step (3B), the precipitate of the titanium hydroxide aggregate is then brought into contact with hydrochloric acid to acid-treat the titanium hydroxide aggregate to obtain an acid-treated titanium hydroxide aggregate.

In the acid treatment in step (3B), the sediment of titanium hydroxide aggregates is brought into contact with hydrochloric acid. At this time, the pH of the liquid phase is 5.0 or less, preferably 2.5 or more and 4.5 or less. , more preferably 3.0 or more and 4.0 or less. When the pH of the liquid phase during the acid treatment is within the above range, the calcium content in the aggregates of titanium hydroxide can be reduced. On the other hand, when the pH of the liquid phase during the acid treatment exceeds the above range, it becomes difficult to obtain the effect of reducing the calcium content in the aggregates of titanium hydroxide.

The acid used for the acid treatment in step (3B) is hydrochloric acid. Since hydrochloric acid is volatilized and removed from the product when the titanium hydroxide is dried or oxidized after the acid treatment, the acid used for the acid treatment hardly remains in the product.

The concentration of hydrochloric acid used for the acid treatment in step (3B) is not particularly limited, but is preferably 1.0 to 8.5 mol/L, preferably 1.5 to 7.0 mol/L, More preferably 2.7 to 5.5 mol/L. When the concentration of hydrochloric acid used for the acid treatment is within the above range, the pH of the liquid phase during the acid treatment can be easily controlled within the desired range. If the concentration of hydrochloric acid used for the acid treatment exceeds the above range, it becomes difficult to control the pH of the liquid phase during the acid treatment, and if it is below the above range, it becomes difficult to carry out the acid treatment smoothly.

The temperature during the acid treatment in step (3B) is not particularly limited, but is preferably 10 to 50°C, more preferably 15 to 45°C, and even more preferably 20 to 40°C.

In the acid treatment in step (3B), the contact time between the precipitate of titanium hydroxide aggregates and hydrochloric acid is preferably 60 to 120 minutes, more preferably 60 to 100 minutes, and more preferably 60 to 100 minutes. More preferably 80 minutes.

In the step (3B), as a method for acid treatment, it is preferable to bring the sediment of titanium hydroxide aggregates into contact with hydrochloric acid in an acid treatment bath.

In step (3B), after the acid treatment is performed to obtain the acid-treated aggregate of titanium hydroxide, a liquid phase is separated from the acid-treated aggregate of titanium hydroxide using a solid-liquid separator. After removal, a dehydrated product of acid-treated titanium hydroxide aggregate is obtained, and the dehydrated product is dried at 60 to 200° C. to obtain an acid-treated titanium hydroxide aggregate. Water and hydrogen chloride are removed from the acid-treated titanium hydroxide agglomerate by removing the liquid phase from the acid-treated titanium hydroxide agglomerate and drying the acid-treated titanium hydroxide agglomerate. is obtained.

In the method for recovering a titanium component according to the second aspect of the present invention, the titanium hydroxide obtained by carrying out the step (3B) is Ti(OH) ₄ . That is, in the method for recovering the titanium component of the present invention, the titanium component is recovered from the waste liquid containing the titanium compound in the form of aggregates of titanium hydroxide. After drying and oxidation, the recovered aggregate of titanium hydroxide (acid-treated product) is converted to titanium oxide and used as a raw material for producing various titanium compounds.

In the method for recovering a titanium component according to the second aspect of the present invention, wastewater containing a titanium compound is hydrolyzed, then primary neutralized at a specific pH using calcium hydroxide as a neutralizing agent, and secondary Secondary neutralization treatment and flocculation treatment are successively performed to generate and precipitate titanium hydroxide agglomerates, and the resulting precipitates of titanium hydroxide agglomerates are subjected to an acid treatment in which hydrochloric acid is brought into contact with the acid. Since the calcium content in the aggregates of titanium hydroxide obtained by the treatment can be reduced, titanium hydroxide with a low calcium content can be recovered. In the method for recovering a titanium component according to the second aspect of the present invention, the precipitate obtained by settling the aggregates of titanium hydroxide produced in the step (2) is treated with an acid to form the aggregates of titanium hydroxide. Since the water-insoluble unreacted substances such as calcium hydroxide remaining in the titanium hydroxide are dissolved, the calcium content in the aggregate of titanium hydroxide can be reduced. From the above, it is considered that the titanium component recovery method of the second aspect of the present invention can recover titanium hydroxide having a low calcium content and low chlorine content.

The method for recovering a titanium component according to the second aspect of the present invention comprises the steps (1), (2), and (3B), and in addition to the step (3B), an acid-treated titanium hydroxide agglomerate. can be washed with washing water having a pH of 6.0 or more and 9.0 or less. In the washing step, washing is carried out by bringing washing water into contact with the acid-treated titanium hydroxide agglomerate obtained in step (3B). The contact method is not particularly limited, and includes, for example, the following methods.

FIG. 6 is a flow diagram showing an example of a mode in which a cleaning step is performed in the method for recovering a titanium component according to the second mode of the present invention. In FIG. 6, a waste liquid 10 containing a titanium compound is transferred to a water receiving tank 1, water 11 is supplied into the water receiving tank 1, the waste liquid 10 containing a titanium compound and water 11 are mixed, and hydrolysis treatment is performed. Apply. Next, the hydrolyzed treated liquid is transferred to the primary neutralization tank 2, the calcium hydroxide suspension 12 is supplied to the primary neutralization tank 2, and the treated liquid in the primary neutralization tank 2 is A primary neutralization treatment is performed so that the pH of is 1.5 or more and less than 2.5. Next, the treated liquid subjected to the primary neutralization treatment is transferred to the secondary neutralization treatment tank 3, the calcium hydroxide suspension 13 is supplied to the secondary neutralization treatment tank 3, and the secondary neutralization treatment tank is A secondary neutralization treatment is performed so that the pH of the treatment liquid in 3 becomes 6.5 or more and 7.5 or less. Next, the treated liquid subjected to the secondary neutralization treatment is transferred to the flocculation tank 4, and a flocculating agent is added to the flocculation tank 4 to flocculate the titanium hydroxide, thereby producing an agglomerate of titanium hydroxide. Let Next, the coagulation treatment liquid containing the resulting titanium hydroxide aggregates is transferred to the sedimentation tank 5, where the titanium hydroxide aggregates are allowed to settle. The precipitate of titanium hydroxide agglomerates is withdrawn. Next, the precipitate of titanium hydroxide agglomerates extracted from the sedimentation tank 5 is transferred to an acid treatment tank 18, and hydrochloric acid 14 is supplied to the acid treatment tank 18 to remove the precipitate of titanium hydroxide agglomerates and hydrochloric acid. 14 are mixed and acid-treated. Next, the acid-treated titanium hydroxide agglomerate is filtered using the filter press device 7 to remove the liquid phase from the acid-treated titanium hydroxide agglomerate, and the titanium hydroxide agglomerate is acidified. By filtering the treated product, a press cake of an acid-treated aggregate of titanium hydroxide is obtained. Next, the press cake of the acid-treated aggregate of titanium hydroxide is transferred to the cleaning tank 32, and the cleaning water 15 is supplied to the cleaning tank 32 to remove the acid-treated aggregate of titanium hydroxide and the cleaning water. 15 are mixed and washed. Next, the washed product of the acid-treated aggregate of titanium hydroxide is filtered using a filter press device 33 to remove the liquid phase from the washed product of the acid-treated aggregate of titanium hydroxide. By filtering the acid-treated titanium agglomerate, a press cake 25 of the acid-treated agglomerate of titanium hydroxide is obtained.

That is, in the first embodiment of the washing step, the acid-treated product of titanium hydroxide aggregate obtained by performing the step (3B) is subjected to a solid-liquid separation device such as a filter press device, a centrifugal separation device, or a liquid cyclone device. to separate the acid-treated aggregates of titanium hydroxide from the liquid phase to obtain a dehydrated product such as press cake; Next, washing is performed by bringing washing water into contact with the dehydrated material.

In the washing step of the first embodiment, after contacting the acid-treated titanium hydroxide agglomerate with washing water, using a solid-liquid separation device such as a filter press device, a centrifugal separator, or a liquid cyclone device, The acid-treated aggregate of titanium hydroxide and the washing water are separated to obtain the acid-treated aggregate of titanium hydroxide.

FIG. 7 is a flow diagram showing another example of a form in which a cleaning step is performed in the method for recovering the titanium component according to the second form of the present invention. In FIG. 7, a waste liquid 10 containing a titanium compound is transferred to a water receiving tank 1, water 11 is supplied into the water receiving tank 1, and the water 11 and the waste liquid 10 containing a titanium compound are mixed to perform a hydrolysis treatment. Apply. Next, the hydrolyzed treated liquid is transferred to the primary neutralization tank 2, the calcium hydroxide suspension 12 is supplied to the primary neutralization tank 2, and the treated liquid in the primary neutralization tank 2 is A primary neutralization treatment is performed so that the pH of is 1.5 or more and less than 2.5. Next, the treated liquid subjected to the primary neutralization treatment is transferred to the secondary neutralization treatment tank 3, the calcium hydroxide suspension 13 is supplied to the secondary neutralization treatment tank 3, and the secondary neutralization treatment tank is A secondary neutralization treatment is performed so that the pH of the treatment liquid in 3 becomes 6.5 or more and 7.5 or less. Next, the treated liquid subjected to the secondary neutralization treatment is transferred to the flocculation tank 4, and a flocculating agent is added to the flocculation tank 4 to flocculate the titanium hydroxide, thereby producing an agglomerate of titanium hydroxide. Let Next, the coagulation treatment liquid containing the resulting titanium hydroxide aggregates is transferred to the sedimentation tank 5, where the titanium hydroxide aggregates are allowed to settle. The precipitate of titanium hydroxide agglomerates is withdrawn. Next, the precipitate of titanium hydroxide agglomerates extracted from the sedimentation tank 5 is transferred to an acid treatment tank 18, and hydrochloric acid 14 is supplied to the acid treatment tank 18 to remove the precipitate of titanium hydroxide agglomerates and hydrochloric acid. 14 are mixed and acid-treated. Next, the acid-treated titanium hydroxide agglomerate is filtered using the filter press device 7 to remove the liquid phase from the acid-treated titanium hydroxide agglomerate, and the titanium hydroxide agglomerate is acidified. After removing the liquid phase from the acid-treated titanium hydroxide agglomerate by filtering the treated material, the filtered material in the filter press device 7 was further pressurized to 0.2 to 0.5 MPa. Washing is performed by supplying washing water 15 and contacting the filtered matter with the washing water 15 at high pressure to perform washing, thereby obtaining a press cake 26 of an acid-treated aggregate of titanium hydroxide.

That is, in the second embodiment of the washing step, the acid-treated titanium hydroxide aggregate obtained by performing the step (3B) is filtered using a filter press to separate the titanium hydroxide aggregate from the liquid phase. Further, washing is performed by supplying washing water pressurized to 0.2 to 0.5 MPa to the filtered matter in the filter press device and contacting the filtered matter with the washing water at high pressure by penetrating washing. be.

The pH of the washing water used in the washing step may be any pH that allows washing without altering the properties of the titanium hydroxide, and is usually 6.0 or more and 9.0 or less. The washing water that can wash the titanium hydroxide without deteriorating its properties is not particularly limited. .

Although the temperature during washing is not particularly limited, it is preferably 10 to 50°C, more preferably 15 to 45°C, even more preferably 20 to 40°C.

After the washing step, a solid-liquid separator is used to separate the liquid phase from the washing treatment liquid containing the acid-treated titanium hydroxide aggregates after washing, and the titanium hydroxide aggregates are dehydrated. Then, the dehydrated product is dried at 60 to 200° C. to obtain an acid-treated aggregate of titanium hydroxide.

In the method for recovering a titanium component according to the second aspect of the present invention, when the waste liquid containing the titanium compound generated during the preparation of the solid catalyst component for olefin polymerization or the catalyst for olefin polymerization contains chlorine, By performing the washing step, the chlorine content in the aggregates of titanium hydroxide can be reduced.

Thus, in the method for recovering a titanium component of the present invention, the titanium compound in the waste liquid containing the titanium compound generated during the preparation of the solid catalyst component for olefin polymerization or the catalyst for olefin polymerization is treated as titanium hydroxide. As a result, titanium hydroxide having a low calcium content can be easily recovered with a high yield.

Next, a method for producing titanium oxide according to the present invention will be described.
The method for producing titanium oxide of the present invention is a method for producing titanium oxide from a waste liquid containing a titanium compound,
A step (1) of contacting the waste liquid containing the titanium compound with water to hydrolyze the titanium compound;
The hydrolyzed treatment liquid is subjected to primary neutralization treatment by adding calcium hydroxide or calcium oxide as a neutralizing agent so that the pH becomes 1.5 or more and less than 2.5, and then the primary neutralization. The treated solution is subjected to secondary neutralization treatment by adding calcium hydroxide or calcium oxide as a neutralizing agent so that the pH becomes 6.5 or more and 7.5 or less, and then titanium hydroxide is aggregated. a step (2) of obtaining an aggregate of titanium hydroxide by subjecting it to an aggregation treatment;
a step (3) after the step (2), in which the aggregate of titanium hydroxide is subjected to an acid treatment by contacting the aggregate with hydrochloric acid to obtain an acid-treated product;
an oxidation step of oxidizing the aggregate of titanium hydroxide to obtain titanium oxide;
having
characterized by Further, the method for producing titanium oxide of the present invention has a washing step of washing the acid-treated titanium hydroxide aggregate obtained by performing the step (3) with washing water having a pH of 6.0 or more and 9.0 or less. be able to.

The method for producing titanium oxide of the present invention comprises step (1), step (2) and step (3), except that it comprises an oxidation step of obtaining titanium oxide by oxidizing an acid-treated titanium hydroxide aggregate. ), step (3A), step (3B), washing step, waste water to be used, treatment, treatment method, etc. are common to the method for recovering the titanium compound of the present invention. It is as described in the description of the method.

The oxidation step in the method for producing titanium oxide of the present invention is a step of obtaining titanium oxide by oxidizing an acid-treated aggregate of titanium hydroxide.

The oxidation conditions in the oxidation step are not particularly limited as long as the conditions are such that titanium hydroxide is oxidized and converted into titanium oxide. For example, the oxidation reaction temperature in the oxidation step is preferably 60 to 1000°C. Also, the oxidation reaction time is appropriately selected. The oxidation reaction atmosphere is an oxidizing atmosphere such as an air atmosphere or an oxygen gas atmosphere. Also, in the oxidation step, the oxidation may be performed only once, or the oxidation may be performed two or more times at the same temperature or at different temperatures.

In the method for producing titanium oxide of the present invention, the step (3) is performed on the titanium hydroxide aggregates obtained by performing the steps (1) and (2). Therefore, the titanium component is removed from the waste liquid containing the titanium compound. Even if calcium hydroxide is used as a neutralizing agent when recovering and obtaining titanium hydroxide, titanium hydroxide with a low calcium content can be obtained, so titanium oxide with a low calcium content can be obtained. . Further, in the method for producing titanium oxide of the present invention, the chlorine content in the titanium oxide can be reduced by further performing a washing step when the waste liquid containing the titanium compound contains chlorine.

Thus, in the method for producing titanium oxide of the present invention, the titanium compound in the waste liquid containing the titanium compound can be recovered as titanium oxide, and the titanium oxide having a low calcium content can be removed by the washing step. When it is carried out, titanium oxide having a low calcium content and a low chlorine content can be easily recovered.

Next, the method for producing the alkali metal titanate of the present invention will be described.
In the method for producing an alkali metal titanate of the present invention, titanium hydroxide recovered by the method for recovering a titanium component of the present invention or titanium oxide obtained by the method for producing titanium oxide of the present invention is used as a raw material. It is characterized.

The method for producing an alkali metal titanate of the present invention uses, as a raw material, titanium hydroxide recovered by the method for recovering a titanium component of the present invention, or titanium oxide obtained by the method for producing titanium oxide of the present invention. A well-known method can be adopted except for the use of

For example, when titanium hydroxide recovered by the method for recovering a titanium component of the present invention is used as the titanium raw material, the titanium oxide obtained after oxidizing the titanium hydroxide and converting it into titanium oxide by an appropriate method. is used as a titanium raw material, and a potassium compound is used as an alkaline raw material, and a raw material mixture containing both is calcined and pulverized to produce an alkali metal titanate. Further, when titanium oxide obtained by the method for producing titanium oxide of the present invention is used as the titanium raw material, the titanium oxide obtained by the method for producing titanium oxide of the present invention is used as the titanium raw material, and an alkali An alkali metal titanate can be produced by using a potassium compound as a raw material and firing and pulverizing a raw material mixture containing both.

The resulting alkali metal titanate is suitable as a friction material for friction sliding members such as brake linings, disc pads, and clutch fadings, which constitute braking devices in automobiles, railway vehicles, aircraft, industrial machinery, and the like. Used.

According to the method for producing an alkali metal titanate of the present invention, high Since a pure titanium compound is used as a raw material, a highly pure alkali metal titanate can be produced at low cost.

EXAMPLES Next, the present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to the following examples.

(Example 1)
<Synthesis of titanium oxide>
Using the processing flow shown in FIG. 2, titanium oxide was obtained from the waste liquid containing the titanium compound.
That is, in a Ziegler-Natta catalyst manufacturing plant, wastewater containing titanium tetrachloride, diethoxymagnesium, toluene and heptane generated when preparing a solid catalyst component for olefin polymerization and having a liquid temperature of 25 ° C. The effluent was mixed by being fed into a water receiving tank 1 having a capacity of 250 m ³ and hydrolyzed. At this time, water 11 for hydrolysis was fed into the water receiving tank so that the pH of the waste liquid in the water receiving tank became 1.
The hydrolyzed treatment liquid is fed into the primary neutralization treatment tank 2 with a capacity of 10 m ³ at a rate of 10 m ³ /h, and a 12.5 mol / L calcium hydroxide aqueous solution at a liquid temperature of 25 ° C. is used to The primary neutralization treatment was carried out so that the pH of the treatment liquid fed into the primary neutralization treatment tank 2 was 2.0.
Next, the treated liquid subjected to the primary neutralization treatment is fed into the secondary neutralization treatment tank 3 having a capacity of 10 m ³ at a rate of 10 m ³ /h, and 12.5 mol / L calcium hydroxide at a liquid temperature of 25 ° C. A secondary neutralization treatment was performed using an aqueous solution so that the pH of the treatment liquid sent into the secondary neutralization treatment tank 3 was 7.2.
The liquid temperature of 25°C that has been subjected to the secondary neutralization treatment is sent into a coagulation tank 4 with a capacity of 10 m ³ at a rate of 10 m ³ /h, and a coagulant (Kurita Chemical Hokuriku Co., Ltd. After flocculation using Farm PA-833) to obtain the flocculation treatment liquid, the flocculation treatment liquid was transferred to the sedimentation tank 5, sedimented in the sedimentation tank 5, and the sediment was extracted from the sedimentation tank 5. . Next, the sediment extracted from the sedimentation tank 5 is transferred to the sediment storage tank 6, the sediment is filtered using the filter press device 7, the liquid phase is removed from the sediment, and the aggregate is filtered. to obtain a press cake of the agglomerates. Then, 530 kg of the press cake of the aggregate was transferred to the acid treatment tank 8 and diluted with 26,500 kg of deionized water. Hydrochloric acid 14 was supplied to the acid treatment tank 8 so that the obtained liquid phase had a pH of 5.0, and the aggregate and the hydrochloric acid 14 were mixed and acid treated. Next, the acid-treated product obtained by the acid treatment is filtered using a filter press device 9 to remove the liquid phase from the acid-treated product, filter the acid-treated product, and of presscake 21 was obtained. The press cake 21 was dried using a hot air circulation dryer at 180° C. for 16 hours to obtain a dried press cake 21 (titanium hydroxide). Next, the dried product (titanium hydroxide) of the obtained press cake 21 is subjected to heat treatment at 850° C. for 2 hours in an air atmosphere using a shuttle kiln, and then further heat treatment at 950° C. for 2 hours. , the desired titanium oxide was obtained.
When the crystal structures of the obtained titanium hydroxide and titanium oxide were measured using an X'PERT-PRO-MPD multipurpose X-ray diffractometer (manufactured by PANalytical), the obtained titanium hydroxide contained a small amount of rutile. Although it contains titanium oxide, it was confirmed that the main crystal system was amorphous, whereas titanium oxide was of the rutile type.

<Synthesis of potassium titanate>
52.16 kg of the obtained titanium oxide, 52.23 kg of titanium ore, 32.28 kg of potassium carbonate powder, 2.87 kg of titanium powder, and 5.7 kg of wood chips (wood pellets) were placed in a vibration rod mill (manufactured by Chuo Kakoki Co., Ltd.). 0.6 kg of a lower alcohol was further added thereto and treated at an amplitude of 5 mm for 15 minutes to obtain a raw material mixture.
145 kg of the above raw material mixture was supplied to a rotary kiln at a temperature of 1170° C. at a flow rate of 14.4 kg/hr. A synthesis reaction to potassium titanate occurred in this rotary kiln, and the fired product was discharged from the rotary kiln. The fired product discharged was rapidly cooled to room temperature.
After that, the cooled baked product is pulverized with a vibrating rod mill (manufactured by Chuo Kakoki Co., Ltd.), and then pulverized with an impact type pulverizer (manufactured by Hosokawa Micron Co., Ltd., ACM Pulverizer) with a built-in classifier to obtain potassium titanate particles. rice field. Table 1 shows the physical properties of the obtained potassium titanate particles. Moreover, the scanning electron microscope observation result (SEM) is shown in FIG.
For comparison, Table 1 also shows physical properties of commercially available potassium titanate particles (TOFIX-SNR-S manufactured by Toho Titanium Co., Ltd.). Moreover, the scanning electron microscope observation result (SEM) is shown in FIG.
The measuring devices and measuring methods used for measuring each physical property are as follows.
<Measuring device>
XRD: X'PERT-PRO-MPD multipurpose X-ray diffractometer (manufactured by PANalytical)
SEM: JSM-7800 (manufactured by JEOL Ltd.)
Specific surface area: monosorb (manufactured by Quantachrome)
Average particle size: PITA-3 (manufactured by Seishin Enterprise Co., Ltd.)

１）６ＫＴＯ：６チタン酸カリウム

1) 6KTO: Potassium hexatitanate

As shown in Table 1, it was confirmed that the potassium titanate particles of Example 1 had the same phase structure and powder shape as those of the commercially available product. Further, the specific surface area (standard value: 2 to 3 m ² /g) and the average particle size (standard value: 25 to 60 µm) were also within the standard values of commercial products.

(Test Examples 1 to 5)
Aggregate press cake (PC) obtained in the same manner as in Example 1 was transferred to acid treatment tank 8 and diluted with ion-exchanged water. Hydrochloric acid 14 is supplied to the acid treatment tank 8 so that the pH of the obtained diluted solution becomes the predetermined value shown in Table 2, and the mixture is stirred for a predetermined time to mix the aggregates and the hydrochloric acid 14, and acid treatment is performed. (Test Examples 3 to 5). In Test Examples 1 and 2, hydrochloric acid was not mixed.
Next, the acid-treated product obtained by the acid treatment is filtered using a filter press device 9 to remove the liquid phase from the acid-treated product, filter the acid-treated product, and of presscake 21 was obtained. The press cake 21 was dried under predetermined conditions to obtain a dried press cake 21 (titanium hydroxide). Table 2 shows the conditions for synthesizing the dried product (titanium hydroxide) of the press cake 21 from the aggregate press cake. In addition, the dried product (titanium hydroxide) of the obtained press cake 21 was subjected to ICP emission spectrometry (Inductivity coupled plasma optical emission spectrometer; ICP-OES) to determine the content of chlorine (Cl) and calcium (Ca). Table 2 also shows the results of measuring the

As shown in Table 2, it was confirmed that the chlorine and calcium contents can be reduced by adjusting the amounts of water and hydrochloric acid added during dilution to make the pH of the liquid phase during acid treatment 5.9 or less. did it.

(Example 2)
<Synthesis of titanium oxide>
Using the processing flow shown in FIG. 6, titanium oxide was obtained from the waste liquid containing the titanium compound.
That is, in a Ziegler-Natta catalyst manufacturing plant, wastewater containing titanium tetrachloride, diethoxymagnesium, toluene and heptane generated when preparing a solid catalyst component for olefin polymerization and having a liquid temperature of 25 ° C. The waste liquid D was mixed by being fed into a water receiving tank 1 having a capacity of 250 m ³ and hydrolyzed. At this time, water 11 for hydrolysis was fed into the water receiving tank so that the pH of the waste liquid in the water receiving tank became 1.
The hydrolyzed treatment solution is fed into the primary neutralization treatment tank 2 with a capacity of 10 m ³ at a rate of 10 m ³ /h, and using a 12.5 mol / L sodium hydroxide aqueous solution at a liquid temperature of 25 ° C., The primary neutralization treatment was carried out so that the pH of the treatment liquid fed into the primary neutralization treatment tank 2 was 2.0.
Next, the treated liquid subjected to the primary neutralization treatment is fed into the secondary neutralization treatment tank 3 having a capacity of 10 m ³ at a rate of 10 m ³ /h, and 12.5 mol / L calcium hydroxide at a liquid temperature of 25 ° C. A secondary neutralization treatment was performed using an aqueous solution so that the pH of the treatment liquid sent into the secondary neutralization treatment tank 3 was 7.2.
The liquid temperature of 25°C that has been subjected to the secondary neutralization treatment is sent into a coagulation tank 4 with a capacity of 10 m ³ at a rate of 10 m ³ /h, and a coagulant (Kurita Chemical Hokuriku Co., Ltd. After flocculation using Farm PA-833) to obtain the flocculation treatment liquid, the flocculation treatment liquid was transferred to the sedimentation tank 5, sedimented in the sedimentation tank 5, and the sediment was extracted from the sedimentation tank 5. . Next, 4000 kg of sediment extracted from sedimentation tank 5 is transferred to acid treatment tank 18, hydrochloric acid 14 is supplied to acid treatment tank 18, the sediment and hydrochloric acid 14 are mixed, and the liquid in acid treatment tank 18 is Acid treatment was applied so that the pH of the phase was 3.5. Next, the obtained acid-treated aggregate is filtered using a filter press device 7 to remove the liquid phase from the acid-treated aggregate, and the acid-treated aggregate is separated by filtration. Thus, a presscake of the acid-treated product of the agglomerates was obtained. Next, the obtained press cake of the acid-treated agglomerates is transferred to the washing tank 32, and 4000 kg of washing water 15 is supplied to the washing tank 32 to wash the acid-treated agglomerates of titanium hydroxide. Washing was performed by mixing 15 parts of water. Next, the obtained washed product of the acid-treated aggregate is filtered using a filter press device 33 to remove the liquid phase from the washed product of the acid-treated aggregate. A press cake 25 of the acid-treated aggregate was obtained by filtering the treated product. The press cake 25 was dried using a hot air circulation dryer at 180° C. for 16 hours to obtain a dried press cake 25 (titanium hydroxide). Next, the dried product (titanium hydroxide) of the obtained press cake 25 is subjected to heat treatment at 850° C. for 2 hours in an air atmosphere using a shuttle kiln, and then further heat treatment at 950° C. for 2 hours. , the desired titanium oxide was obtained.
When the crystal structures of the obtained titanium hydroxide and titanium oxide were measured using an X'PERT-PRO-MPD multipurpose X-ray diffractometer (manufactured by PANalytical), the obtained titanium hydroxide contained a small amount of rutile. Although it contains titanium oxide, it was confirmed that the main crystal system was amorphous, whereas titanium oxide was of the rutile type.

<Synthesis of potassium titanate>
52.16 kg of the obtained titanium oxide, 52.23 kg of titanium ore, 32.28 kg of potassium carbonate powder, 2.87 kg of titanium powder, and 5.70 kg of wood chips (wood pellets) were placed in a vibration rod mill (manufactured by Chuo Kakoki Co., Ltd.). 0.6 kg of a lower alcohol was further added thereto and treated at an amplitude of 5 mm for 15 minutes to obtain a raw material mixture.
Approximately 140 kg of the above raw material mixture was supplied to a rotary kiln at a temperature of 1170° C. at a flow rate of 14.4 kg/hr. A synthesis reaction to potassium titanate occurred in this rotary kiln, and the fired product was discharged from the rotary kiln. The fired product discharged was rapidly cooled to room temperature.
After that, the cooled baked product is pulverized with a vibrating rod mill (manufactured by Chuo Kakoki Co., Ltd.), and then pulverized with an impact type pulverizer (manufactured by Hosokawa Micron Co., Ltd., ACM Pulverizer) with a built-in classifier to obtain potassium titanate particles. rice field. Table 3 shows the physical properties of the obtained potassium titanate particles. Moreover, the scanning electron microscope observation result (SEM) is shown in FIG.
For comparison, Table 3 also shows physical properties of commercially available potassium titanate particles (TOFIX-SNR-S manufactured by Toho Titanium Co., Ltd.). Moreover, the scanning electron microscope observation result (SEM) is shown in FIG.
The measuring devices and measuring methods used for measuring each physical property are as follows.
≪Measuring device≫
XRD: X'PERT-PRO-MPD multipurpose X-ray diffractometer (manufactured by PANalytical)
SEM: JSM-7800 (manufactured by JEOL Ltd.)
Specific surface area: monosorb (manufactured by Quantachrome)
Average particle size: PITA-3 (manufactured by Seishin Enterprise Co., Ltd.)

１）６ＫＴＯ：６チタン酸カリウム

1) 6KTO: Potassium hexatitanate

As shown in Table 3, it was confirmed that the potassium titanate particles of Example 2 had the same phase structure and powder shape as those of the commercially available product. Further, the specific surface area (standard value: 2 to 3 m ² /g) and the average particle size (standard value: 25 to 60 µm) were also within the standard values of commercial products.

(Test Examples 6 to 8)
The precipitate extracted from the sedimentation tank 5 obtained in the same manner as in Example 2 is transferred to an acid treatment tank 18, and hydrochloric acid 14 is supplied to the acid treatment tank 18 and stirred for a predetermined time to remove the precipitate and hydrochloric acid. 14 were mixed, and acid treatment was performed so that the pH of the mixed liquid in the acid treatment tank 18 reached the predetermined value shown in Table 4 (Test Examples 7 and 8). In Test Example 6, hydrochloric acid was not mixed.
Next, the obtained acid-treated aggregate is filtered using a filter press device 7 to remove the liquid phase from the acid-treated aggregate, and the acid-treated aggregate is separated by filtration. Thus, a presscake of the acid-treated product of the agglomerates was obtained. The press cake was dried under predetermined conditions to obtain a dried press cake (titanium hydroxide). Table 4 shows the conditions for synthesizing the dried press cake (titanium hydroxide) from the sediment extracted from the sedimentation tank 5 . In addition, the result of measuring the calcium (Ca) content of the dried presscake (titanium hydroxide) using ICP optical emission spectrometer (ICP-OES) is also included. are shown in Table 4.

As shown in Table 4, it was confirmed that the calcium content can be reduced by adjusting the amount of water and hydrochloric acid added at the time of dilution to set the pH of the liquid phase at the time of acid treatment to 5.9 or less. .

From Tables 1 and 3, in Examples 1 and 2, the waste liquid containing the titanium compound was brought into contact with water, and the titanium compound was subjected to hydrolysis treatment after hydrolysis treatment. The aqueous phase of the waste liquid is subjected to primary neutralization treatment by adding a neutralizing agent so that the pH becomes 1.5 or more and less than 2.5. A secondary neutralization treatment is carried out by adding a neutralizing agent to a pH of 6.5 or more and 7.5 or less, and then the titanium hydroxide aggregates produced by aggregating the titanium hydroxide are treated with hydrochloric acid having a pH of 5.9 or less. By contacting with, a titanium compound can be easily obtained without using a neutralizing agent such as ammonia water or sodium hydroxide, and a high-purity titanium compound in which impurities such as calcium are suppressed can be obtained. It is understood that

Further, from Tables 2 and 4, in Test Examples 4, 7 and 8, the aggregates of titanium hydroxide produced by aggregating titanium hydroxide after the secondary neutralization treatment had a pH of 5.9 or less. It can be seen that impurities such as calcium in the obtained titanium compound are removed by contacting with hydrochloric acid.
On the other hand, in Test Examples 1 to 3, 5 and 6, hydrochloric acid having a pH of 5.9 or less was not brought into contact with the aggregates of titanium hydroxide produced by aggregating the titanium hydroxide after the secondary neutralization treatment. Therefore, it can be seen that impurities such as calcium are not removed from the resulting titanium compound.

According to the present invention, a waste liquid containing a titanium compound, for example, a waste liquid containing a titanium compound such as a titanium compound-containing waste liquid generated during the preparation of a solid catalyst component for olefin polymerization or a catalyst for olefin polymerization. Therefore, even if calcium hydroxide or calcium oxide is used as a neutralizing agent, it is possible to provide a method for easily recovering a titanium compound with high purity, and a waste liquid containing a titanium compound, for example, for olefin polymerization Even if calcium hydroxide or calcium oxide is used as a neutralizing agent, a titanium compound can be removed from a waste liquid containing a titanium compound, such as a waste liquid containing a titanium compound generated during the preparation of a solid catalyst component or a catalyst for olefin polymerization. It is possible to provide a method for easily producing a highly pure titanate, and further to provide a method for producing a highly pure alkali metal titanate at low cost.

1 Receiving tank 2 Primary neutralization tank 3 Secondary neutralization tank 4 Coagulation tank 5 Sedimentation tank 6 Sediment storage tank 7, 9, 33 Filter press device 8, 18 Acid treatment tank 10 Waste liquid containing titanium compound 11 Water 12, 13 Calcium hydroxide suspension 14 Hydrochloric acid 15 Wash water 19 Titanium hydroxide compound aggregate 20 Titanium hydroxide compound aggregate 21, 22, 23, 24, 25, 26 Titanium hydroxide compound Aggregate acid-treated press cakes 31, 32 Washing tank

Claims (13)

A method for recovering a titanium component from a waste liquid containing a titanium compound, comprising:
a step (1) of contacting the waste liquid containing the titanium compound with water to hydrolyze the titanium compound;
The hydrolyzed treatment liquid is subjected to primary neutralization treatment by adding calcium hydroxide or calcium oxide as a neutralizing agent so that the pH becomes 1.5 or more and less than 2.5, and then the primary neutralization. The treated solution is subjected to secondary neutralization treatment by adding calcium hydroxide or calcium oxide as a neutralizing agent so that the pH becomes 6.5 or more and 7.5 or less, and then titanium hydroxide is aggregated. a step (2) of obtaining an aggregate of titanium hydroxide by performing an aggregation treatment to
a step (3), after the step (2), of subjecting the aggregates of titanium hydroxide to acid treatment by contacting the aggregates of titanium hydroxide with hydrochloric acid to obtain an acid-treated product of the aggregates of titanium hydroxide;
having
A method for recovering a titanium component, characterized by: After the step (2) is carried out to obtain the titanium hydroxide aggregate concentrate, the titanium hydroxide aggregate concentrate is separated, and then the titanium hydroxide aggregate concentrate is and a step (3A) of bringing the aggregate of titanium hydroxide into contact with hydrochloric acid to acid-treat the aggregate of titanium hydroxide to obtain an acid-treated product of the aggregate of titanium hydroxide. Ingredient recovery method. 3. The method according to claim 2, wherein in the step (3A), a concentrate of the titanium hydroxide agglomerates is obtained by allowing the agglomerates of the titanium hydroxide produced by performing the step (2) to settle. A method for recovering a titanium component. In the step (3A), after the agglomerate of titanium hydroxide produced by performing the step (2) is allowed to settle, the sediment of the agglomerate of titanium hydroxide is separated, and then the agglomerate of titanium hydroxide is separated. 3. A concentrate of the titanium hydroxide agglomerate is obtained by dehydration treatment for removing the liquid phase from the precipitate to obtain a dehydrated product of the agglomerate of titanium hydroxide. method for recovering the titanium component of After the step (2) is carried out to precipitate the titanium hydroxide aggregate, the precipitate of the titanium hydroxide aggregate is brought into contact with hydrochloric acid to acid-treat the titanium hydroxide aggregate. 2. The method for recovering a titanium component according to claim 1, further comprising a step (3B) of obtaining an acid-treated aggregate of titanium hydroxide. The titanium component according to any one of claims 1 to 5, further comprising a washing step of washing the acid-treated titanium hydroxide aggregate with washing water of 6.0 or more and 9.0 or less. collection method. A method for producing titanium oxide by producing titanium oxide from a waste liquid containing a titanium compound,
a step (1) of contacting the waste liquid containing the titanium compound with water to hydrolyze the titanium compound;
The hydrolyzed treatment liquid is subjected to primary neutralization treatment by adding calcium hydroxide or calcium oxide as a neutralizing agent so that the pH becomes 1.5 or more and less than 2.5, and then the primary neutralization. The treated solution is subjected to secondary neutralization treatment by adding calcium hydroxide or calcium oxide as a neutralizing agent so that the pH becomes 6.5 or more and 7.5 or less, and then titanium hydroxide is aggregated. a step (2) of obtaining an aggregate of titanium hydroxide by performing an aggregation treatment to
a step (3), after the step (2), of subjecting the aggregates of titanium hydroxide to acid treatment by contacting the aggregates of titanium hydroxide with hydrochloric acid to obtain an acid-treated product of the aggregates of titanium hydroxide;
an oxidation step of obtaining titanium oxide by oxidizing the acid-treated aggregate of titanium hydroxide;
having
A method for producing titanium oxide, characterized by: After the step (2) is carried out to obtain the titanium hydroxide aggregate concentrate, the titanium hydroxide aggregate concentrate is separated, and then the titanium hydroxide aggregate concentrate is 8. The titanium according to claim 7, further comprising a step (3A) of bringing the aggregate of titanium hydroxide into contact with hydrochloric acid to acid-treat the aggregate of titanium hydroxide to obtain an acid-treated product of the aggregate of titanium hydroxide. Ingredient recovery method. 9. The method according to claim 8, wherein in the step (3A), the titanium hydroxide agglomerates are allowed to settle by performing the step (2) to obtain a concentrate of the titanium hydroxide agglomerates. A method for recovering a titanium component. In the step (3A), after the agglomerate of titanium hydroxide produced by performing the step (2) is allowed to settle, the sediment of the agglomerate of titanium hydroxide is separated, and then the agglomerate of titanium hydroxide is separated. 9. A concentrate of the titanium hydroxide agglomerate is obtained by performing a dehydration treatment to remove the liquid phase from the sediment and obtaining a dehydrated product of the agglomerate of titanium hydroxide. method for recovering the titanium component of After the step (2) is carried out to precipitate the titanium hydroxide aggregate, the precipitate of the titanium hydroxide aggregate is brought into contact with hydrochloric acid to acid-treat the titanium hydroxide aggregate. 8. The method for producing titanium oxide according to claim 7, further comprising a step (3B) of obtaining an acid-treated aggregate of titanium hydroxide. 12. The titanium oxide according to any one of claims 7 to 11, further comprising a washing step of washing the acid-treated titanium hydroxide aggregate with washing water of 6.0 or more and 9.0 or less. Production method. Titanium hydroxide recovered by the method for recovering a titanium component according to any one of claims 1 to 6, or titanium oxide obtained by the method for producing titanium oxide according to any one of claims 7 to 12, as a raw material A method for producing an alkali metal titanate, characterized by using

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