Method for recovering titanium component, method for producing titanium oxide, method for producing alkali titanate, method for producing friction material, and method for producing titanium tetrachloride raw material

Abstract

To provide a method for recovering titanium components capable of reducing the chlorine content in recovered titanium components.SOLUTION: A method for recovering titanium components includes: a primary step of supplying a suspension containing the acid-treated titanium hydroxide aggregate into the space in a compression section of a filter press apparatus, filling the suspension containing the acid-treated titanium hydroxide aggregate in the compression section, and compressing the compression section and the suspension at 0.10 to 1.00 MPa by a pressurized filtration chamber to remove water from the suspension to obtain a primary pressed material; a through washing step of performing through washing on the primary pressed material to obtain a through-washed product; and a secondary pressing step of pressing the compression section and the through-washed product through the pressurized filtration chamber to remove water from the through-washed product to obtain an acid-treated cake of titanium hydroxide aggregates.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a method for recovering titanium components from waste liquid.

Background Art

[0002] Conventionally, titanium oxysulfate and polymerized silicic acid are used in combination, and after adding and mixing them to the sludge to be treated at a ratio such that the molar ratio of silicon to titanium in the titanium oxysulfate is 1 or more and 10 or less to aggregate inorganic particles, mechanical dehydration treatment is performed using a filter press or the like. A method for dehydrating sludge mainly composed of inorganic particles is known.

[0003] In this method, after adding and mixing titanium oxysulfate to drainage or sludge mainly composed of inorganic particles generated in water purification treatment of tap water and civil engineering work, etc., the pH is adjusted to 8 to 11 using an alkaline agent such as caustic soda or soda ash. Thereby, titanium hydroxide hydrate is generated to cause an aggregation action of inorganic particles. Next, polymerized silicic acid is added in a range where the molar ratio to titanium in the previously added titanium oxysulfate is 1 or more and 10 or less, and after sufficiently mixing and stirring to form flocs, dehydration is performed using a filter press or a centrifuge.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, in order to recover titanium components from a drainage containing titanium tetrachloride instead of titanium oxysulfate, it is common to go through the following steps. That is, titanium tetrachloride in the drainage containing titanium tetrachloride is hydrolyzed, and then a calcium hydroxide suspension is supplied to the hydrolyzed drainage to adjust the pH of the drainage to approximately 1 to 6. After adding a flocculant to flocculate titanium hydroxide, the titanium hydroxide flocculates are sedimented in a sedimentation tank. Next, the sedimented titanium hydroxide flocculates are transferred to an acid treatment tank, hydrochloric acid is supplied into the acid treatment tank, the titanium hydroxide flocculates and hydrochloric acid are mixed, and the acid treatment of the titanium hydroxide flocculates is carried out. Next, the treatment liquid containing the acid-treated product of the titanium hydroxide flocculates is filtered using a filter press device to separate the acid-treated product of the titanium hydroxide flocculates, and by obtaining a press cake of the acid-treated product of the titanium hydroxide flocculates, the titanium components are recovered. At this time, since chlorine remains in the recovered titanium components due to calcium chloride generated in the neutralization step or hydrochloric acid used for acid washing, there is a demand to reduce the content of chlorine remaining from calcium chloride or hydrochloric acid in the recovered titanium components.

[0006] Therefore, an object of the present invention is to provide a method for recovering titanium components capable of reducing the content of chlorine in the recovered titanium components.

Means for Solving the Problems

[0007] In order to solve the above technical problems, the inventors of the present invention conducted intensive studies and arrived at the following configuration.

[0008] That is, the present invention is (1) A method for recovering titanium components from a drainage containing a titanium compound, comprising: performing at least a hydrolysis treatment, a primary neutralization treatment using calcium hydroxide or calcium oxide as a neutralizing agent, a secondary neutralization treatment using calcium hydroxide or calcium oxide as a neutralizing agent, and a flocculation treatment for flocculating titanium hydroxide on the drainage containing the titanium compound to obtain titanium hydroxide flocculates, a titanium hydroxide flocculation treatment step; After the titanium hydroxide agglomeration treatment step, an acid treatment is performed in which hydrochloric acid or titanium chloride is brought into contact with the titanium hydroxide agglomerate to obtain a suspension containing the acid-treated product of the titanium hydroxide agglomerate; A suspension containing the acid-treated product of the titanium hydroxide agglomerate is fed into the space inside the compression part of a filter press device having a pressure filtration chamber and a compression part provided inside the pressure filtration chamber, having a filtration membrane and filled with the material to be filtered. The suspension containing the acid-treated product of the titanium hydroxide agglomerate is filled into the compression part. Then, the compression part and the suspension are squeezed at 0.10 to 1.00 MPa by the pressure filtration chamber to remove moisture from the suspension, and a primary squeezed product of the acid-treated product of the titanium hydroxide agglomerate is obtained; a primary squeezing step; Washing water is supplied inside the pressure filtration chamber and outside the compression part, and a washing liquid is caused to flow so as to penetrate the compression part and the primary squeezed product of the acid-treated product of the titanium hydroxide agglomerate inside it, and the primary squeezed product of the acid-treated product of the titanium hydroxide agglomerate is washed through, and a through-washed product of the acid-treated product of the titanium hydroxide agglomerate is obtained; a through-washing step; The compression part and the through-washed product of the acid-treated product of the titanium hydroxide agglomerate are squeezed by the pressure filtration chamber to remove moisture from the through-washed product of the acid-treated product of the titanium hydroxide agglomerate, and a cake of the acid-treated product of the titanium hydroxide agglomerate is obtained; a secondary squeezing step; A method for recovering a titanium component, characterized by comprising the above; (2) The method for recovering a titanium component according to (1), wherein in the through-washing step, the insertion pressure of the washing water is 0.10 to 0.60 MPa and the washing time is 17 to 60 minutes; (3) The method for recovering a titanium component according to (1) or (2), wherein the squeezing pressure in the secondary squeezing step is 0.10 to 1.00 MPa; (4) The method for recovering a titanium component according to any one of (1) to (3), wherein the squeezing time in the secondary squeezing step is longer than the squeezing time in the primary squeezing step; (5) The method for recovering a titanium component according to any one of (1) to (4), wherein the pressure of the washing water in the through-washing step is 0.10 to 0.60 MPa; A method for producing titanium oxide from a waste liquid containing a titanium compound, comprising: performing at least a hydrolysis treatment, a primary neutralization treatment using calcium hydroxide or calcium oxide as a neutralizing agent, a secondary neutralization treatment using calcium hydroxide or calcium oxide as a neutralizing agent, and a flocculation treatment for flocculating titanium hydroxide on the waste liquid containing the titanium compound to obtain a titanium hydroxide flocculate in a titanium hydroxide flocculation treatment step; performing an acid treatment of contacting the titanium hydroxide flocculate with hydrochloric acid or titanium chloride at a stage subsequent to the titanium hydroxide flocculation treatment step to obtain a suspension containing an acid-treated product of the titanium hydroxide flocculate in an acid treatment step; feeding the suspension containing the acid-treated product of the titanium hydroxide flocculate into a space inside a compression part of a filter press apparatus having a pressurized filtration chamber and the compression part provided inside the pressurized filtration chamber and having a filtration membrane and filled with a material to be filtered, filling the space inside the compression part with the suspension containing the acid-treated product of the titanium hydroxide flocculate, and then squeezing the compression part and the suspension at 0.10 to 1.00 MPa by the pressurized filtration chamber to remove moisture from the suspension to obtain a primary squeezed product of the acid-treated product of the titanium hydroxide flocculate in a primary squeezing step; supplying washing water inside the pressurized filtration chamber and outside the compression part, flowing a washing liquid so as to penetrate the compression part and the primary squeezed product of the acid-treated product of the titanium hydroxide flocculate inside thereof to perform through-washing of the primary squeezed product of the acid-treated product of the titanium hydroxide flocculate to obtain a through-washed product of the acid-treated product of the titanium hydroxide flocculate in a through-washing step; squeezing the compression part and the through-washed product of the acid-treated product of the titanium hydroxide flocculate by the pressurized filtration chamber to remove moisture from the through-washed product of the acid-treated product of the titanium hydroxide flocculate to obtain a cake of the acid-treated product of the titanium hydroxide flocculate in a secondary squeezing step; firing the acid-treated product of the titanium hydroxide flocculate after performing the secondary squeezing step to obtain titanium oxide in a firing step; characterized by comprising the above steps. A method for producing an alkali titanate, characterized by using titanium hydroxide recovered by the method for recovering any one of the titanium components (1) to (5) or titanium oxide obtained by the method for producing titanium oxide (6) as a raw material; A method for producing a friction material, characterized by using the alkali titanate obtained by the method for producing an alkali titanate (7) as a raw material; A method for producing a titanium tetrachloride raw material, characterized by using titanium hydroxide recovered by the method for recovering any one of the titanium components (1) to (5) as a raw material; is provided.

Effects of the Invention

[0009] According to the present invention, a method for recovering a titanium component capable of reducing the chlorine content in the recovered titanium component can be provided.

Brief Description of the Drawings

[0010]

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Mode for Carrying Out the Invention

[0011] The method for recovering a titanium component of the present invention is a method for recovering a titanium component from a drainage containing a titanium compound, for the drainage containing the titanium compound, at least a hydrolysis treatment, a primary neutralization treatment using calcium hydroxide or calcium oxide as a neutralizing agent, a secondary neutralization treatment using calcium hydroxide or calcium oxide as a neutralizing agent, and an aggregation treatment for aggregating titanium hydroxide are performed to obtain a titanium hydroxide aggregate in a titanium hydroxide aggregation treatment step, in a subsequent stage from the titanium hydroxide aggregation treatment step, an acid treatment is performed by bringing hydrochloric acid or titanium chloride into contact with the titanium hydroxide aggregate to obtain a suspension containing an acid-treated product of the titanium hydroxide aggregate in an acid treatment step, a suspension containing an acid-treated product of the titanium hydroxide aggregate is fed into a space inside the compression part of a filter press device having a pressurized filtration chamber and a compression part provided inside the pressurized filtration chamber, having a filtration membrane and filled with a material to be filtered, the suspension containing the acid-treated product of the titanium hydroxide aggregate is filled into the compression part, and then the compression part and the suspension are squeezed at 0.10 to 1.00 MPa by the pressurized filtration chamber to remove moisture from the suspension to obtain a primary squeezed product of the acid-treated product of the titanium hydroxide aggregate in a primary squeezing step, washing water is supplied inside the pressurized filtration chamber and outside the compression part, and a washing liquid is caused to flow so as to penetrate the compression part and the primary squeezed product of the acid-treated product of the titanium hydroxide aggregate inside it to perform through-washing of the primary squeezed product of the acid-treated product of the titanium hydroxide aggregate to obtain a through-washed product of the acid-treated product of the titanium hydroxide aggregate in a through-washing step, A secondary pressing step of pressing the compressed portion and the through-washed product of the acid-treated product of the titanium hydroxide aggregate through the pressurized filtration chamber to remove moisture from the through-washed product of the acid-treated product of the titanium hydroxide aggregate to obtain a cake of the acid-treated product of the titanium hydroxide aggregate; It is characterized by having.

[0012] The overall image of the method for recovering the titanium component of the present invention will be described with reference to FIG. 1. Here, a form in which calcium hydroxide is applied as a neutralizing agent will be described as an example. However, in the present invention, even if calcium oxide is applied as a neutralizing agent, the same effect as when calcium hydroxide is applied can be obtained. FIG. 1 is a flowchart of a form example of the method for recovering the titanium component of the present invention. In FIG. 1, the drainage 10 containing the titanium compound is transferred to the receiving water tank 1, water 11 is supplied into the receiving water tank 1, the drainage 10 containing the titanium compound and water 11 are mixed, and a hydrolysis treatment is performed. Next, the treated liquid of the hydrolyzed drainage is transferred to the primary neutralization treatment tank 2, and a calcium hydroxide suspension 12 is supplied to the primary neutralization treatment tank 2 to perform a primary neutralization treatment so that the pH of the drainage in the primary neutralization treatment tank 2 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, and a calcium hydroxide suspension 13 is supplied to the secondary neutralization treatment tank 3 to perform a secondary neutralization treatment so that the pH of the drainage in the secondary neutralization treatment tank 3 is 2.5 or more and 7.5 or less. Next, the treated liquid subjected to the secondary neutralization treatment is transferred to the coagulation tank 4, a coagulant is added to the coagulation tank 4 to coagulate titanium hydroxide, and then transferred to the sedimentation tank 5 to sediment the titanium hydroxide aggregate in the sedimentation tank 5. Next, the sedimented titanium hydroxide aggregate is transferred to the sediment storage tank 6. Next, the sediment is transferred to the acid treatment tank 7, hydrochloric acid 14 is supplied to the acid treatment tank 7 to perform acid treatment on the titanium hydroxide aggregate, and a suspension containing the acid-treated product of the titanium hydroxide aggregate is obtained. Next, a primary pressing step, a through-washing step, and a secondary pressing step are performed on the suspension containing the acid-treated product of the titanium hydroxide aggregate using a filter press device 8 to obtain a press cake 20 of the titanium hydroxide aggregate. In the form example shown in FIG. 1, among the above steps, the step of obtaining the titanium hydroxide aggregate from the drainage containing the titanium compound is defined as the titanium hydroxide aggregation treatment step. The details of the titanium hydroxide aggregation treatment step and the acid treatment step will be described later.

[0013] In the method for recovering a titanium component of the present invention, the object to which the method for recovering a titanium component is applied is a drainage containing a titanium compound, and there is no particular limitation as long as it contains a titanium compound. As the drainage containing a titanium compound, "titanium-containing drainage" generated when preparing a solid catalyst component for olefin polymerization or a catalyst for olefin polymerization is preferable.

[0014] In the method for recovering a titanium component of the present invention, when the drainage containing a titanium compound is a titanium-containing drainage generated when preparing a solid catalyst component for olefin polymerization or a catalyst for olefin polymerization, the solid catalyst component for olefin polymerization or the catalyst for olefin polymerization is not particularly limited as long as it is a solid catalyst component or a catalyst containing a titanium component used for the polymerization of olefins. For example, a Ziegler-Natta catalyst used for the production of polyolefins, a metallocene catalyst, a post-metallocene, a solid titanium catalyst for the production of polyethylene terephthalate, etc., and one or more selected from the solid catalyst components constituting these catalysts can be mentioned. Among these, one or more selected from the Ziegler-Natta catalyst, metallocene catalyst, and post-metallocene catalyst used for the production of polyolefins and the solid catalyst components constituting these catalysts are preferable, and a Ziegler-Natta catalyst or a solid catalyst component constituting a Ziegler-Natta catalyst is more preferable.

[0015] As the Ziegler-Natta catalyst or the solid catalyst component constituting the Ziegler-Natta catalyst, among the above, a solid catalyst component for olefin polymerization prepared by bringing a magnesium compound, a titanium compound, a halogen compound, and further, an electron-donating compound as necessary, into contact with each other is suitable.

[0016] As the magnesium compound used for the preparation of the solid catalyst component for olefin polymerization, those containing a halogen and those that change into a halogen-containing magnesium compound by contact reaction with a halogen-containing compound are preferable. Examples of such magnesium compounds include one or more selected from magnesium dihalides such as magnesium chloride, dialkylmagnesiums such as alkoxymagnesium halide, alkylmagnesium halide, and dialkoxymagnesiums such as diethoxymagnesium. Magnesium chloride or diethoxymagnesium is preferred.

[0017] Examples of the titanium compound according to the method for recovering a titanium component of the present invention include, for example, the following general formula (1): Ti(OR) N X 4-N (1) (In the formula, R represents a hydrocarbon group, X represents a halogen atom. When a plurality of Xs are present, each X may be the same or different, and N is an integer of 0 to 4.) Titanium compounds represented by the formula are exemplified.

[0018] 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, and even more preferably a hydrocarbon group having 1 to 4 carbon atoms.

[0019] Specific examples of the titanium compound represented by the general formula (1) include titanium tetrahalides such as titanium tetrachloride, titanium tetrafluoride, titanium tetrabromide, and titanium tetraiodide, alkoxytitanium trihalides such as methoxytitanium trichloride, ethoxytitanium trichloride, propoxytitanium trichloride, and N-butoxytitanium trichloride, dialkoxytitanium dihalides such as dimethoxytitanium dichloride, diethoxytitanium dichloride, dipropoxytitanium dichloride, and di-N-butoxytitanium dichloride, and alkoxytitanium halides such as trialkoxytitanium halides such as trimethoxytitanium chloride, triethoxytitanium chloride, tripropoxytitanium chloride, and tri-N-butoxytitanium chloride. One or more selected from tetraalkoxytitanium are exemplified.

[0020] Among the above titanium compounds, halogen-containing titanium compounds are preferred, tetrahalogenated titaniums selected from titanium tetrachloride, titanium tetrafluoride, titanium tetrabromide, titanium tetraiodide, etc. are more preferred, and titanium tetrachloride is even more preferred. The above titanium compound may be diluted with a hydrocarbon compound or a halogenated hydrocarbon compound, etc.

[0021] The electron-donating compound used in the preparation of the solid catalyst component for olefin polymerization is not particularly limited, but includes one or more selected from alcohols, phenols, ketones, aldehydes, carboxylic acids, acid halides, esters of organic or inorganic acids, ethers, acid amides, acid anhydrides, ammonia, amines, nitriles, isocyanates, nitrogen-containing cyclic compounds, oxygen-containing cyclic compounds, organosilicon compounds, etc.

[0022] In the method for recovering the titanium component of the present invention, the drainage containing a titanium compound is an organic solvent component used during washing, heat contact, etc. in the preparation process of the solid catalyst component for olefin polymerization, specifically, saturated hydrocarbon compounds such as pentane, hexane, heptane, octane, nonane, decane, dodecane, kerosene, cyclopentane, cyclohexane, methylcyclopentane, methylcyclohexane, ethylcyclohexane, 1,2-diethylcyclohexane, methylcyclohexene, decalin, mineral oil, etc., aromatic hydrocarbon compounds such as benzene, toluene, xylene, ethylbenzene, etc., halogenated hydrocarbon compounds such as orthodichlorobenzene, methylene chloride, 1,2-dichlorobenzene, carbon tetrachloride, dichloroethane, ethylene chloride, chlorobenzene, dichloromethane, etc., and may contain one or more organic solvent components selected from aluminum compounds, silicon compounds, etc.

[0023] In the method for recovering the titanium component of the present invention, as the drainage containing a titanium compound, those containing magnesium chloride or diethoxymagnesium as the magnesium compound, an alkoxytitanium halogen compound or a halogenated titanium compound as the titanium compound, and further containing an electron-donating compound and an organic solvent component are preferred.

[0024] In the method for recovering a titanium component of the present invention, the drainage containing a titanium compound is drainage generated by various reactions, etc., for example, drainage generated during the preparation of a solid catalyst component for olefin polymerization or a catalyst for olefin polymerization, and is not particularly limited as long as it contains a titanium compound. The drainage containing a titanium compound is preferably drainage generated during the preparation of a solid catalyst component for olefin polymerization or a catalyst for olefin polymerization, and such drainage contains a titanium compound not supported on the solid catalyst component and other titanium compounds newly generated by reactions in its preparation process. In the method for recovering a titanium component of the present invention, the drainage containing a titanium compound preferably contains the titanium compound in an amount of 0.01 to 35.0% by mass, more preferably 0.05 to 10.0% by mass, and even more preferably 0.10 to 5.0% by mass.

[0025] Hereinafter, with reference to FIG. 2, the details of the method for recovering a titanium component of the present invention will be described. In the method for recovering a titanium component according to the present invention, a suspension containing an acid-treated product of titanium hydroxide aggregates in the acid treatment tank 7 is treated in a filter press device 8. Then, as shown in FIG. 2, in the method for recovering a titanium component according to the present invention, in the filter press device 8, a suspension containing an acid-treated product of titanium hydroxide aggregates is subjected to a primary pressing step, a through washing step, and a secondary pressing step without performing positive washing to wash the titanium hydroxide aggregates and obtain a cake of the acid-treated product of titanium hydroxide aggregates. Next, a cake discharging step of taking out the obtained titanium hydroxide aggregates outside the filter press device is performed. That is, the method for recovering a titanium component of the present invention subjects the drainage containing a titanium compound to a titanium hydroxide aggregation treatment step and an acid treatment step, and performs a primary pressing step, a through washing step, and a secondary pressing step on the suspension containing the acid-treated product of the obtained titanium hydroxide aggregates without performing positive washing.

[0026] As the suspension containing the acid-treated product of titanium hydroxide aggregates according to the method for recovering titanium components of the present invention, at least hydrolysis treatment, primary neutralization treatment using calcium hydroxide or calcium oxide as a neutralizing agent, secondary neutralization treatment using calcium hydroxide or calcium oxide as a neutralizing agent, and aggregation treatment for aggregating titanium hydroxide are performed on the drainage containing the titanium compound, whereby a titanium hydroxide aggregation treatment step for obtaining titanium hydroxide aggregates is carried out. In a subsequent stage after the titanium hydroxide aggregation treatment step, an acid treatment is performed in which hydrochloric acid or titanium chloride is brought into contact with the titanium hydroxide aggregates, and a suspension containing the acid-treated product of the titanium hydroxide aggregates, which is an aggregate of titanium hydroxide, is obtained. It is obtained by performing an acid treatment step. The titanium hydroxide aggregation treatment step and the acid treatment step will be described later.

[0027] The primary pressing step according to the method for recovering titanium components of the present invention is to send a suspension containing the acid-treated product of titanium hydroxide aggregates into the space inside the compression part of a filter press device having a pressurized filtration chamber and a compression part provided inside the pressurized filtration chamber, having a filtration membrane and filled with the material to be filtered, fill the compression part with the suspension containing the acid-treated product of titanium hydroxide aggregates, and then press the compression part and the suspension at 0.10 to 1.00 MPa by the pressurized filtration chamber to remove moisture from the suspension, obtaining a primary pressed product of the acid-treated product of titanium hydroxide aggregates.

[0028] As shown in FIG. 3, the filter press device 8 includes a filtration chamber 31, a compression part 36 provided inside the pressurized filtration chamber 31 and having a filtration membrane 32, a filter plate 33 that forms part of the partition wall of the filtration chamber 31, another part 35 of the partition wall of the filtration chamber 31, and a squeezing membrane 34 provided in the filtration chamber 31 and configured to be movable to pressurize the inside of the filtration chamber 31. The compression part 36 has a filtration membrane 32. The filtration membrane 32 is located at a position where it sandwiches a suspension containing an acid-treated product of titanium hydroxide aggregates during at least the primary squeezing process, that is, at a position between the suspension and the filter plate 33, and is arranged at a position where washing water is supplied or discharged to the primary squeezed product of the acid-treated product of titanium hydroxide aggregates during through washing. The filtration membrane 32 is a general filtration membrane for a filter press device and is formed of materials such as polyester, nylon-6, and polypropylene.

[0029] The filter plate 33 and the squeezing membrane 34 may have uneven surfaces at the locations where they contact the filtration membrane 32. The squeezing membrane 34 can move forward and backward by means of a diaphragm mechanism (not shown). By driving the diaphragm mechanism to move the squeezing membrane 34 forward with respect to the filtration membrane 32, the suspension containing the acid-treated product of titanium hydroxide aggregates inside the filtration membrane 32 can be squeezed and filtered to remove moisture from the suspension. Thereby, a primary squeezed product of the acid-treated product of titanium hydroxide aggregates can be obtained.

[0030] In the primary squeezing process, first, a suspension containing an acid-treated product of titanium hydroxide aggregates is sent into the space inside the compression part of a filter press device having a pressurized filtration chamber and a compression part provided inside the pressurized filtration chamber, and the space inside the compression part is filled with the suspension containing the acid-treated product of titanium hydroxide aggregates. The compression part has a filtration membrane. The filtration membrane is located at a position where it sandwiches a suspension containing an acid-treated product of titanium hydroxide aggregates during at least the primary squeezing process, that is, at a position between the suspension containing the acid-treated product of titanium hydroxide aggregates and the member applying a squeezing force to the suspension containing the acid-treated product of titanium hydroxide aggregates, and is arranged at a position where washing water is supplied or discharged to the primary squeezed product of the acid-treated product of titanium hydroxide aggregates during through washing.

[0031] The filling of the suspension of the acid-treated product of titanium hydroxide aggregates into the compression section is carried out so that the acid-treated product of titanium hydroxide aggregates is in an overall homogeneous state in the filtration chamber. In the case of a suspension containing the acid-treated product of titanium hydroxide aggregates, the suspension (cake) of the acid-treated product of titanium hydroxide aggregates often fills the filtration chamber (compression section). In such a state where the suspension (cake) of the acid-treated product of titanium hydroxide aggregates is filled, it is impossible to secure the washing water flow path necessary for the subsequent positive washing in the suspension (cake) of the acid-treated product of titanium hydroxide aggregates. Therefore, in the case of a suspension (cake) containing the acid-treated product of titanium hydroxide aggregates, it is suitable to first perform primary pressing on the suspension of the acid-treated product of titanium hydroxide aggregates to form the acid-treated product of titanium hydroxide aggregates into a cake shape, and then perform the through washing described below. Generally, the through washing has the advantage that less washing water is required compared to the positive washing.

[0032] In the primary pressing step, next, the compression section and the suspension are pressed at 0.10 to 1.00 MPa by a pressure-type filtration chamber to remove moisture from the suspension, and a primary pressed product of the acid-treated product of titanium hydroxide aggregates is obtained. The pressing pressure in the primary pressing step is 0.10 to 1.00 MPa, preferably 0.20 to 1.00 MPa, and more preferably 0.30 to 1.00 MPa. The pressing time in the primary pressing step is 30 seconds to 10 minutes, preferably 1 to 5 minutes, and most preferably 2 to 4 minutes.

[0033] The filter press device used in the primary pressing step is not particularly limited as long as it has a pressure-type filtration chamber, can press the compression section filled with the object to be filtered in the filtration chamber, separate the filtrate in the object to be filtered by filtration through the filter membrane in the compression section, and can perform the through washing described below on the object to be filtered in the filtration chamber after the primary pressing. Examples of such filter press devices include the HJMF type manufactured by Kurita Machinery Works, Ltd. and the ISD type manufactured by Ishigaki Co., Ltd.

[0034] As the filter membrane of the compression part provided in the filter press device, there is no particular limitation as long as it can separate the filtrate from the object to be filtered by filtration during the first and second pressings, and can supply or discharge washing water to enable through washing during through washing. Examples of the material include polyester, nylon, and polypropylene.

[0035] The through washing step according to the method for recovering titanium components of the present invention is a step of supplying washing water inside the pressurized filtration chamber and outside the filter membrane of the compression part, flowing the washing liquid so as to penetrate the compression part and the primary press cake of the acid-treated product of titanium hydroxide aggregates inside it, performing through washing on the primary press cake of the acid-treated product of titanium hydroxide aggregates, and obtaining a through-washed product of the acid-treated product of titanium hydroxide aggregates.

[0036] Referring to FIG. 3, the through washing in the through washing step will be described. In through washing, as shown by the arrow in FIG. 3, the supply of washing water is performed, for example, from the filter membrane 32 on the side of the pressing membrane 34. At this time, the washing water passes through the filter membrane 32 and the primary press cake (cake) of the acid-treated product of titanium hydroxide aggregates as shown by the arrow in the figure. As a result, the mother liquor of the primary press cake of the acid-treated product of titanium hydroxide aggregates is replaced with washing water. The washing water replaced in the primary press cake of the aggregates is discharged into the filtration chamber 31 from the filter membrane 32 on the side of the filter plate 33 opposite to the side of the pressing membrane 34 as shown by the arrow in the figure. The washing water discharged into the filtration chamber 31 is appropriately discharged outside the filtration chamber 31 through the discharge channel.

[0037] As the cleaning water in the through cleaning process, any water that can clean without altering titanium hydroxide is acceptable and not particularly limited. Examples include ion-exchanged water, pure water, ultrapure water, industrial water, well water, tap water, etc. The pressure of the cleaning water in the through cleaning process is 0.10 - 1.00 MPa, preferably 0.20 - 0.70 MPa, and more preferably 0.30 - 0.70 MPa. The cleaning time in the through cleaning process is 17 - 60 minutes, preferably 18 - 27 minutes, and most preferably 20 - 25 minutes. Even if the cleaning time is 60 minutes or more, the cleaning effect can be ensured. However, from the perspectives of industrial cost reduction and water resource protection, 60 minutes of cleaning is sufficient.

[0038] The pH of the cleaning water used in the through cleaning process may be any pH that can clean without altering titanium hydroxide and is usually 6.0 or more and 9.0 or less.

[0039] The temperature during through cleaning is not particularly limited, but is preferably 10 - 50°C, more preferably 15 - 45°C, and even more preferably 20 - 40°C.

[0040] Next, with reference to Figure 4, the normal cleaning as a comparative example to the through cleaning will be described. In normal cleaning, the cleaning water is supplied using the supply line that supplies the suspension containing the acid-treated product of titanium hydroxide aggregates into the filtration chamber 31. In normal cleaning, while the inside of the filtration membrane 32 is not completely filled with the suspension (cake) of the acid-treated product of titanium hydroxide aggregates, cleaning water is supplied to the central part inside the filtration membrane 32 to form a flow path for the cleaning water in the center of the cake. Thereby, the cleaning water is passed in the same direction as filtration. As shown by the arrow in Figure 4, the cleaning water passes through the cake in the direction of the filtration membrane and is discharged into the filtration chamber 31 from the filtration membrane 32 on the side of the pressing membrane, for example, or the filtration membrane 32 on the side of the filter plate 33 opposite to the pressing membrane 34 side. The cleaning water discharged into the filtration chamber 31 is appropriately discharged outside the filtration chamber 31 through the discharge flow path. Since the thickness of the cake becomes thinner in normal cleaning, if the cleaning pressure and the flow rate of the cleaning water are the same, the cleaning time will be shorter than that of through cleaning.

[0041] The secondary pressing step in the method for recovering titanium components according to the present invention is a step of pressing the compressed part and the through-washed product of the acid-treated product of titanium hydroxide aggregates by a pressure filtration chamber to remove moisture from the through-washed product of the acid-treated product of titanium hydroxide aggregates, thereby obtaining a cake of the acid-treated product of titanium hydroxide aggregates.

[0042] For example, after performing through-washing, further, the compressed part 36 and the through-washed product of the acid-treated product of titanium hydroxide aggregates are pressed by a pressure filtration chamber 31 to remove moisture from the through-washed product of the acid-treated product of titanium hydroxide aggregates, thereby obtaining a cake of the acid-treated product of titanium hydroxide aggregates.

[0043] The pressing pressure in the secondary pressing step is equal to or higher than the pressing pressure in the primary pressing step. More specifically, the pressing pressure in the secondary pressing step of the present invention is preferably 0.10 to 1.00 MPa, more preferably 0.20 to 1.00 MPa, and even more preferably 0.30 to 1.00 MPa.

[0044] The pressing time in the secondary pressing step is preferably longer than the pressing time in the primary pressing step. More specifically, the pressing time in the secondary pressing step is preferably 3 to 14 minutes, more preferably 5 to 12 minutes, even more preferably 6 to 11 minutes, and most preferably 7 to 10 minutes.

[0045] In the secondary pressing step, similar to the primary pressing step, the pressing membrane 34 can move forward and backward by a diaphragm mechanism (not shown) or the like. By driving the diaphragm mechanism, the pressing membrane 34 moves forward with respect to the compression part 36, thereby pressing and filtering the through-washed product of the acid-treated product of titanium hydroxide aggregates in the compression part 36 to remove moisture from the acid-treated product of titanium hydroxide aggregates. Thereby, a cake of the acid-treated product of titanium hydroxide aggregates can be obtained.

[0046] Next, each step in the titanium hydroxide aggregation treatment process will be described. In the method for recovering the titanium component of the present invention, the suspension of the acid-treated product of the titanium hydroxide aggregate treated in the primary pressing step is a suspension of the acid-treated product of the titanium hydroxide aggregate obtained by subjecting the drainage containing the titanium compound to the titanium hydroxide aggregation treatment step and the acid treatment step. The titanium hydroxide aggregation treatment step has a step A of bringing the drainage containing the titanium compound into contact with water and subjecting the titanium compound to a hydrolysis treatment. In step A, the hydrolysis method is not particularly limited, and examples thereof include a method of bringing it into contact with water separately injected into a receiving tank for receiving the drainage.

[0047] In step A, when the titanium compound is titanium halide, by bringing the drainage containing the titanium compound into contact with water, the titanium compound is hydrolyzed to produce hydrogen halide and titanium hydroxide.

[0048] In the hydrolysis treatment according to step A, the pH of the mixed solution of the drainage containing the titanium compound and water is preferably 0.5 or more and 2.0 or less, more preferably 0.7 or more and 1.5 or less, and even more preferably about 1.0. When the pH of the mixed solution of the drainage containing the titanium compound and water is within the above range, it becomes difficult for the titanium hydroxide generated in the mixed solution to precipitate, and the subsequent treatment can be carried out smoothly.

[0049] In step A, the amount of water brought into contact with the drainage containing the titanium compound is preferably 3 to 10 m 3 per 1 m of the drainage containing the titanium compound, more preferably 4 to 7 m 3 and even more preferably 5 to 6 m 3 of water. 3

[0050] In step A, 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.

[0051] In Project A, the contact time between the effluent containing the titanium compound and water is preferably 30 to 60 minutes, more preferably 35 to 55 minutes, and even more preferably 40 to 50 minutes.

[0052] The titanium hydroxide flocculation treatment step has Step B. Step B related to the titanium hydroxide flocculation treatment step is a step of subjecting the effluent that has undergone hydrolysis treatment in Step A to primary neutralization treatment and then secondary neutralization treatment to obtain titanium hydroxide.

[0053] In Step B, first, a primary neutralization treatment is performed by adding calcium hydroxide or calcium oxide to the treatment liquid of the effluent that has undergone hydrolysis treatment in Step A so that the pH becomes 1.5 or more and less than 2.5.

[0054] In the primary neutralization treatment, calcium hydroxide or calcium oxide is added to the treatment liquid of the effluent that has undergone hydrolysis treatment in Step A so that the pH becomes 1.5 or more and less than 2.5, preferably so that the pH becomes 1.8 or more and 2.3 or less, and more preferably so that the pH becomes 1.8 or more and 2.2 or less. When the pH during the primary neutralization treatment is within the above range, flocculation and sedimentation are likely to occur, and it becomes easier to recover the titanium component from the effluent containing the titanium compound with high purity. On the other hand, when the pH during the primary neutralization treatment is less than the above range, it becomes difficult to perform smooth neutralization treatment, and when the pH exceeds the above range, gel-like titanium hydroxide is generated, and the sedimentation property and filterability decrease.

[0055] The neutralizing agent used in the primary neutralization treatment is calcium hydroxide or calcium oxide. By using calcium hydroxide or calcium oxide as the neutralizing agent in the primary neutralization treatment, the cost of the neutralizing agent can be suppressed, and there is an advantage that the sedimentation property and filterability of the titanium compound obtained by neutralization are improved. 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 property and filterability of the titanium compound obtained by neutralization deteriorate, which is industrially disadvantageous.

[0056] In the primary neutralization treatment, a suspension in which calcium hydroxide or calcium oxide is dispersed in water is brought into contact with the treatment liquid of the effluent subjected to the hydrolysis treatment. The content of calcium hydroxide or calcium oxide in the suspension is appropriately selected according to the set value of the pH 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, it is easy to control the pH in the effluent subjected to the hydrolysis treatment within a desired range. On the other hand, when the content of calcium hydroxide in the suspension exceeds the above range, it becomes difficult to control the pH in the effluent subjected to the hydrolysis treatment, and when it is less than the above range, it becomes difficult to perform a smooth neutralization treatment.

[0057] The temperature during the primary neutralization treatment is not particularly limited, but is preferably 10°C or higher.

[0058] In the primary neutralization treatment, the contact time between the treatment liquid of the effluent subjected to the hydrolysis treatment and calcium hydroxide or calcium oxide is not particularly limited, but is usually about 60 to 120 minutes.

[0059] In step B, as a method for performing the primary neutralization treatment, it is preferable to bring calcium hydroxide or calcium oxide into contact in a neutralization tank (primary neutralization treatment tank) with respect to the treatment liquid of the effluent subjected to the hydrolysis treatment. The primary neutralization treatment tank may be a single tank or a plurality of tanks connected in communication.

[0060] In step B, then, a secondary neutralization treatment is performed in which 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.

[0061] In the secondary neutralization treatment related to Process B, calcium hydroxide or calcium oxide is added to the treated liquid that has undergone the primary neutralization treatment so that the pH becomes 2.5 or more and 7.5 or less. And in the secondary neutralization treatment related to Process B, calcium hydroxide or calcium oxide is added to the treated liquid that has undergone the primary neutralization treatment so that the pH becomes 2.5 or more and 7.5 or less, preferably so that the pH becomes 3.0 to 7.5, more preferably so that the pH becomes 3.5 to 7.5, and even more preferably so that the pH becomes 6.5 to 7.5.

[0062] Since the pH in the secondary neutralization treatment is within the above range, the calcium content in the titanium hydroxide aggregate obtained through the flocculation treatment is reduced, and flocculation and sedimentation are likely to occur, making it easier to recover the titanium component from the titanium compound-containing drainage with high purity. On the other hand, if the pH during the secondary neutralization treatment is less than the above range, it becomes difficult for titanium hydroxide to precipitate, and if it exceeds the above range, the calcium content in the obtained titanium hydroxide becomes too high.

[0063] The neutralizing agent used in the secondary neutralization treatment is calcium hydroxide or calcium oxide. By using calcium hydroxide or calcium oxide as the neutralizing agent in the secondary neutralization treatment, the cost of the neutralizing agent can be suppressed, and there is also the advantage that the sedimentation property and filterability of the titanium compound that can be neutralized are improved. 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 becomes large, and the sedimentation property and filterability of the titanium compound that can be neutralized become poor, which is industrially disadvantageous.

[0064] In the secondary neutralization treatment, a suspension in which calcium hydroxide or calcium oxide is dispersed in water is brought into contact with the treated 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 set value of the pH 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 in the drained liquid subjected to the hydrolysis treatment within the desired range. On the other hand, when the content of calcium hydroxide in the suspension exceeds the above range, it becomes difficult to control the pH in the drained liquid subjected to the hydrolysis treatment, and when it is less than the above range, it becomes difficult to perform a smooth neutralization treatment.

[0065] The temperature during the secondary neutralization treatment is not particularly limited, but is preferably 10°C or higher.

[0066] In the secondary neutralization treatment, the contact time between the treated liquid that has undergone the primary neutralization treatment and calcium hydroxide or calcium oxide is not particularly limited, but is usually about 60 to 120 minutes.

[0067] In step B, as a method for performing the secondary neutralization treatment, it is preferable to bring calcium hydroxide or calcium oxide into contact in a neutralization tank (secondary neutralization treatment tank) with respect to the treated liquid that has undergone the primary neutralization treatment. The secondary neutralization treatment tank may be a single tank or a plurality of tanks connected in communication.

[0068] Further, it is preferable that the treated liquid after the secondary neutralization treatment does not contain calcium hydroxide. The content of calcium hydroxide in the treated liquid after the secondary neutralization treatment is adjusted by the amount of the neutralizing agent added in the secondary neutralization treatment, the set value of the pH in the secondary neutralization treatment, etc.

[0069] The titanium hydroxide aggregation treatment step includes step C. Step C related to the titanium hydroxide aggregation treatment step is a step of subjecting the treated liquid that has undergone the secondary neutralization treatment in step B to an aggregation treatment for aggregating titanium hydroxide in the treated liquid to obtain aggregates of titanium hydroxide. The aggregation treatment is preferably performed using a flocculant such as an anionic polymer flocculant.

[0070] In Process C, when titanium hydroxide in the treated liquid subjected to secondary neutralization treatment is aggregated using a flocculant, a flocculant such as an anionic polymer flocculant is added to the treated liquid subjected to secondary neutralization treatment to aggregate titanium hydroxide, whereby titanium hydroxide is obtained in the form of titanium hydroxide aggregates. The aggregation of titanium hydroxide is preferably carried out in an aggregation tank by feeding the treated liquid subjected to secondary neutralization treatment into the tank. Then, by performing the aggregation treatment, titanium hydroxide aggregates are formed.

[0071] Regarding the aqueous phase obtained after separating titanium hydroxide in Process C, it is preferable to adjust the acidity to neutral (pH 6.5 to 7.5) and then appropriately perform waste liquid treatment.

[0072] In the method for recovering the titanium component of the present invention, for the wastewater containing a titanium compound, after hydrolysis treatment, calcium hydroxide or calcium oxide is used as a neutralizing agent, and primary neutralization treatment and secondary neutralization treatment are sequentially performed at a specific pH, whereby the calcium content in the obtained titanium hydroxide can be reduced, and since it becomes easier to aggregate or precipitate titanium hydroxide, titanium hydroxide with a low calcium content can be recovered. In the method for recovering the titanium component of the present invention, by setting the pH of the secondary neutralization treatment to be 2.5 or more and 7.5 or less, preferably 3.0 to 7.5, more preferably 3.5 to 7.5, and even more preferably 6.5 to 7.5, unreacted calcium hydroxide is reduced, and titanium hydroxide with good aggregability or sedimentation property is formed, so that the calcium content in titanium hydroxide or titanium hydroxide aggregates can be reduced, and titanium hydroxide can be easily aggregated or precipitated. From the above, it is considered that the method for recovering the titanium component of the present invention can recover titanium hydroxide with a low calcium content.

[0073] In the method for recovering the titanium component of the present invention, after performing the titanium hydroxide aggregation treatment step, the resulting titanium hydroxide aggregate is sedimented in a sedimentation tank, and the sediment of the titanium hydroxide aggregate in the sedimentation tank is extracted, whereby the titanium hydroxide aggregate is separated in the state of the sediment of the titanium hydroxide aggregate. Although the sediment of this titanium hydroxide aggregate contains the liquid phase derived from the previous treatment, in the acid treatment step performed after the titanium hydroxide aggregation treatment step, it may be subjected to the treatment after removing the liquid phase in the sediment of the titanium hydroxide aggregate, or it may be subjected to the treatment without removing the liquid phase in the sediment of the titanium hydroxide aggregate.

[0074] In the method for recovering the titanium component of the present invention, in the treatment step after the titanium hydroxide aggregation treatment step and before the primary pressing step, an acid treatment step is performed in which hydrochloric acid or titanium chloride is brought into contact with the titanium hydroxide aggregate. In the method for recovering the titanium component of the present invention, the timing of performing the acid treatment step is not particularly limited as long as it is after the titanium hydroxide aggregation treatment step and before the primary pressing step. And, in the method for recovering the titanium component of the present invention, by bringing hydrochloric acid or titanium chloride into contact with the titanium hydroxide aggregate, the calcium content in the titanium hydroxide aggregate can be reduced.

[0075] In the acid treatment step according to the method for recovering the titanium component of the present invention, hydrochloric acid or titanium chloride is brought into contact with the titanium hydroxide aggregate obtained by performing the titanium hydroxide aggregation treatment step. At this time, however, hydrochloric acid or titanium chloride is brought into contact so that the pH of the liquid phase becomes 5.9 or less. When the pH of the liquid phase during the acid treatment is within the above range, the calcium content in the titanium hydroxide aggregate 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 titanium hydroxide aggregate. Regarding the upper limit of the pH of the liquid phase during the acid treatment, it is preferably 5.7 or less, more preferably 5.5 or less, and still more preferably 5.3 or less. Also, regarding the lower limit of the pH of the liquid phase during the acid treatment, it is preferably 2.0 or more, more preferably 3.0 or more.

[0076] The acid used in the acid treatment is hydrochloric acid or titanium chloride. Since titanium chloride hydrolyzes to produce hydrochloric acid and titanium hydroxide when the pH of the liquid phase is 2.0 or higher, using titanium chloride in the acid treatment can obtain the same acid treatment effect as contacting the titanium hydroxide aggregate with hydrochloric acid. As the titanium chloride, a waste liquid containing a titanium compound whose titanium compound is titanium chloride is preferable in terms of reducing the production cost.

[0077] The concentration of hydrochloric acid used in the acid treatment is not particularly limited, but it is preferably 1.0 to 13.0 mol / L, more preferably 1.5 to 12.0 mol / L, and even more preferably 2.7 to 12.0 mol / L. When the concentration of hydrochloric acid used in 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 in 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 less than the above range, it becomes difficult to perform a smooth acid treatment.

[0078] The concentration of titanium chloride used in the acid treatment is not particularly limited, but the concentration of hydrochloric acid generated by hydrolysis is preferably 1.0 to 13.0 mol / L, more preferably 1.5 to 12.0 mol / L, and even more preferably 2.7 to 12.0 mol / L.

[0079] The temperature during the acid treatment is not particularly limited, but it is preferably 10 to 50 °C, more preferably 15 to 45 °C, and even more preferably 20 to 40 °C.

[0080] In the acid treatment, the contact time between the titanium hydroxide aggregate obtained by performing the titanium hydroxide aggregation treatment step and hydrochloric acid or titanium chloride is preferably 10 minutes or more, more preferably 20 minutes or more, even more preferably 30 minutes or more, and even more preferably 60 minutes or more.

[0081] In the method for recovering the titanium component of the present invention, any method may be used as long as it involves bringing the titanium hydroxide aggregate into contact with hydrochloric acid in the acid treatment step. Examples of the acid treatment step include the following forms.

[0082] The method for recovering the titanium component according to the first embodiment of the present invention includes an acid treatment step (A) in which, after obtaining a concentrate of the titanium hydroxide aggregate produced by performing the titanium hydroxide aggregation step, the concentrate of the titanium hydroxide aggregate is separated, and then the concentrate of the titanium hydroxide aggregate is brought into contact with hydrochloric acid to perform acid treatment on the titanium hydroxide aggregate to obtain an acid-treated product of the titanium hydroxide aggregate.

[0083] Regarding the form example having a titanium hydroxide aggregation step and an acid treatment step (A) according to the method for recovering a titanium component in the first form of the present invention, it will be described with reference to FIG. 5. FIG. 5 is a flowchart of a form example of the titanium hydroxide aggregation step and the acid treatment step (A) according to the method for recovering a titanium component in the first form of the present invention. Here, a form in which calcium hydroxide is applied as a neutralizing agent will be described as an example. However, in the present invention, even if calcium oxide is applied as a neutralizing agent, the same effect as when calcium hydroxide is applied can be obtained. In FIG. 5, the drainage 10 containing a titanium compound is transferred to the receiving tank 1, and water 11 is supplied into the receiving tank 1 to mix the drainage 10 containing a titanium compound and the water 11, and a hydrolysis treatment is performed. Next, the hydrolyzed treatment liquid is transferred to the primary neutralization treatment tank 2, and a calcium hydroxide suspension 12 is supplied to the primary neutralization treatment tank 2 to perform a primary neutralization treatment so that the pH of the treatment liquid in the primary neutralization treatment tank 2 is 1.5 or more and less than 2.5. Next, the treatment liquid subjected to the primary neutralization treatment is transferred to the secondary neutralization treatment tank 3, and a calcium hydroxide suspension 13 is supplied to the secondary neutralization treatment tank 3 to perform a secondary neutralization treatment so that the pH of the treatment liquid in the secondary neutralization treatment tank 3 is 2.5 or more and 7.5 or less. Next, the treatment liquid subjected to the secondary neutralization treatment is transferred to the aggregation tank 4, and a flocculant is added to the aggregation tank 4 to aggregate titanium hydroxide, thereby generating a titanium hydroxide aggregate. Next, the aggregation treatment liquid containing the generated titanium hydroxide aggregate is transferred to the sedimentation tank 5, and in the sedimentation tank 5, the titanium hydroxide aggregate is sedimented, and the sediment of the titanium hydroxide aggregate is extracted from the lower part or the bottom of the sedimentation tank 5. Next, the sediment of the titanium hydroxide aggregate extracted from the sedimentation tank 5 is transferred to the sediment storage tank 6. Next, the sediment of the titanium hydroxide aggregate is filtered using a filter press device 81 to remove the liquid phase from the sediment of the titanium hydroxide aggregate, and the titanium hydroxide aggregate is filtered off to obtain a press cake of the titanium hydroxide aggregate. Next, the press cake of the titanium hydroxide aggregate is transferred to the acid treatment tank 7, and hydrochloric acid 14 is supplied to the acid treatment tank 7 to mix the titanium hydroxide aggregate and the hydrochloric acid 14, and an acid treatment is performed.Next, a primary pressing step, a through-washing step, and a secondary pressing step are performed on a suspension containing an acid-treated product of titanium hydroxide aggregates using a filter press apparatus 82 to wash the acid-treated product of titanium hydroxide aggregates and remove the liquid phase, filter the acid-treated product of titanium hydroxide aggregates, and obtain a press cake 21 of the acid-treated product of titanium hydroxide aggregates.

[0084] The method for recovering a titanium component according to the first aspect of the present invention includes a titanium hydroxide aggregation treatment step and an acid treatment step (A). The neutralization treatment, primary neutralization treatment, secondary neutralization treatment, and aggregation treatment in the titanium hydroxide aggregation treatment step according to the method for recovering a titanium component of the first aspect of the present invention are common to the method for recovering a titanium compound of the present invention, and the details thereof are the same as the description of the method for recovering a titanium component of the present invention.

[0085] In the acid treatment step (A) according to the method for recovering a titanium component of the first aspect of the present invention, after obtaining a concentrate of titanium hydroxide aggregates produced by performing the titanium hydroxide aggregation treatment step, the obtained concentrate of titanium hydroxide aggregates is separated from the aggregation treatment liquid.

[0086] In the acid treatment step (A), the method for obtaining a concentrate of titanium hydroxide aggregates from the aggregation treatment liquid containing titanium hydroxide aggregates after performing the titanium hydroxide aggregation treatment step is not particularly limited. For example, first, (i) the aggregation treatment liquid containing titanium hydroxide aggregates after performing the titanium hydroxide aggregation treatment step is transferred to a sedimentation tank, and the titanium hydroxide aggregates are sedimented in the sedimentation tank. Next, (ii) the sediment of titanium hydroxide aggregates is extracted from the lower part or bottom of the sedimentation tank to separate the sediment of titanium hydroxide aggregates from the aggregation treatment liquid, and the sediment of titanium hydroxide aggregates extracted from the sedimentation tank is transferred to a sediment storage tank to obtain the sediment of titanium hydroxide aggregates, that is, a concentrate of titanium hydroxide aggregates.

[0087] In addition, in the acid treatment step (A), as a method for obtaining a concentrate of titanium hydroxide aggregates from the agglomeration treatment liquid containing titanium hydroxide aggregates after the titanium hydroxide agglomeration treatment step, for example, the agglomeration treatment liquid containing titanium hydroxide aggregates after the titanium hydroxide agglomeration treatment step is treated with a liquid cyclone, a screw decanter, etc. to separate the aqueous phase from the agglomeration treatment liquid, and a method for obtaining a concentrate of titanium hydroxide aggregates can be mentioned.

[0088] In addition, in the acid treatment step (A), as a method for obtaining a concentrate of titanium hydroxide aggregates from the agglomeration treatment liquid containing titanium hydroxide aggregates after the titanium hydroxide agglomeration treatment step, first, the titanium hydroxide aggregates generated by performing the titanium hydroxide agglomeration treatment are allowed to settle, and then the sediment of the titanium hydroxide aggregates is separated from the agglomeration treatment liquid. Next, a dehydration treatment for removing the liquid phase from the sediment of the titanium hydroxide aggregates is performed to obtain a dehydrated product of the titanium hydroxide aggregates, that is, a method for obtaining a concentrate of the titanium hydroxide aggregates can be mentioned. As the dehydration treatment method, for example, a method of filtering using a solid-liquid separation device such as a filter press device, a centrifugal separation device, or a liquid cyclone device can be mentioned.

[0089] In the acid treatment step (A), then, hydrochloric acid or titanium chloride is brought into contact with the concentrate of the titanium hydroxide aggregates to perform acid treatment on the titanium hydroxide aggregates.

[0090] In the acid treatment according to the acid treatment step (A), hydrochloric acid or titanium chloride is brought into contact with the dehydrated product of the titanium hydroxide aggregates. At this time, hydrochloric acid is brought into contact so that the pH of the liquid phase is 5.9 or less, preferably 2.0 or more and 5.5 or less, more preferably 3.5 or more and 5.0 or less. When the pH of the liquid phase during acid treatment is within the above range, the calcium content in the titanium hydroxide aggregates can be reduced. On the other hand, when the pH of the liquid phase during acid treatment exceeds 5.9, it becomes difficult to obtain the effect of reducing the calcium content in the titanium hydroxide aggregates.

[0091] The acid used in the acid treatment according to the acid treatment step (A) is hydrochloric acid or titanium chloride.

[0092] The concentration of hydrochloric acid used in the acid treatment related to the acid treatment step (A) is not particularly limited, but is preferably 1.0 to 13.0 mol / L, more preferably 1.5 to 12.0 mol / L, and even more preferably 2.7 to 12.0 mol / L. When the concentration of hydrochloric acid used in 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 in 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 less than the above range, it becomes difficult to perform a smooth acid treatment.

[0093] The concentration of titanium chloride used in the acid treatment step (A) is not particularly limited, but is preferably a concentration such that the concentration of hydrochloric acid generated by hydrolysis is preferably 1.0 to 13.0 mol / L, more preferably 1.5 to 12.0 mol / L, and even more preferably 2.7 to 12.0 mol / L.

[0094] The temperature during the acid treatment related to the acid treatment step (A) 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.

[0095] In the acid treatment related to the acid treatment step (A), the contact time between the concentrate of titanium hydroxide aggregates and hydrochloric acid is appropriately selected, but is preferably 10 minutes or more, more preferably 20 minutes or more, and even more preferably 30 minutes or more.

[0096] In the acid treatment step (A), as a method of performing the acid treatment, it is preferable to bring hydrochloric acid or titanium chloride into contact with the concentrate of titanium hydroxide aggregates in an acid treatment tank.

[0097] And by performing the acid treatment step (A), a suspension of the acid-treated product of titanium hydroxide aggregates is obtained.

[0098] In the titanium hydroxide aggregation treatment step and the acid treatment step (A) according to the method for recovering a titanium component in the first embodiment of the present invention, after hydrolysis treatment of wastewater containing a titanium compound, calcium hydroxide or calcium oxide is used as a neutralizing agent, and primary neutralization treatment, secondary neutralization treatment, and aggregation treatment are sequentially performed at a specific pH to produce a titanium hydroxide aggregate. Then, the aqueous phase is separated, and an acid treatment step of bringing hydrochloric acid or titanium chloride into contact with the concentrate of the obtained titanium hydroxide aggregate is performed to reduce the calcium content in the titanium hydroxide aggregate obtained by the acid treatment. Therefore, titanium hydroxide with a low calcium content can be recovered. In the method for recovering a titanium component in the first embodiment of the present invention, by performing acid treatment on the concentrate of the titanium hydroxide aggregate generated in the titanium hydroxide aggregation treatment step, that is, by performing acid treatment on the titanium hydroxide aggregate, hardly water-soluble unreacted substances such as calcium hydroxide remaining in the titanium hydroxide aggregate are dissolved, so that the calcium content in the titanium hydroxide aggregate can be reduced. From the above, it is considered that the method for recovering a titanium component in the first embodiment of the present invention can recover titanium hydroxide with a low calcium content.

[0099] The method for recovering a titanium component in the second embodiment of the present invention is a form having an acid treatment step (B) in which after the titanium hydroxide aggregate generated by performing the titanium hydroxide aggregation treatment step is sedimented, hydrochloric acid or titanium chloride is brought into contact with the sediment of the titanium hydroxide aggregate to perform acid treatment on the titanium hydroxide aggregate to obtain an acid-treated product of the titanium hydroxide aggregate.

[0100] A morphological example having a titanium hydroxide aggregation treatment step and an acid treatment step (B) according to the method for recovering a titanium component in the second form of the present invention will be described with reference to FIG. 6. FIG. 6 is a flowchart of a morphological example of the titanium hydroxide aggregation treatment step and the acid treatment step (B) according to the method for recovering a titanium component in the second form of the present invention. Here, a form in which calcium hydroxide is applied as a neutralizing agent will be described as an example. However, in the present invention, even if calcium oxide is applied as a neutralizing agent, the same effect as when calcium hydroxide is applied can be obtained. In FIG. 6, the drainage liquid 10 containing a titanium compound is transferred to the receiving tank 1, water 11 is supplied into the receiving tank 1, the drainage liquid 10 containing a titanium compound and the water 11 are mixed, and a hydrolysis treatment is performed. Next, the hydrolyzed treatment liquid is transferred to the primary neutralization treatment tank 2, a calcium hydroxide suspension 12 is supplied to the primary neutralization treatment tank 2, and a primary neutralization treatment is performed so that the pH of the treatment liquid in the primary neutralization treatment tank 2 becomes 1.5 or more and less than 2.5. Next, the treatment liquid subjected to the primary neutralization treatment is transferred to the secondary neutralization treatment tank 3, a calcium hydroxide suspension 13 is supplied to the secondary neutralization treatment tank 3, and a secondary neutralization treatment is performed so that the pH of the treatment liquid in the secondary neutralization treatment tank 3 becomes 2.5 or more and 7.5 or less. Next, the treatment liquid subjected to the secondary neutralization treatment is transferred to the aggregation tank 4, a flocculant is added to the aggregation tank 4, and titanium hydroxide is aggregated to generate a titanium hydroxide aggregate. Next, the aggregation treatment liquid containing the generated titanium hydroxide aggregate is transferred to the sedimentation tank 5, and in the sedimentation tank 5, the titanium hydroxide aggregate is sedimented, and the sediment of the titanium hydroxide aggregate is extracted from the lower part or the bottom of the sedimentation tank 5. Next, the sediment of the titanium hydroxide aggregate extracted from the sedimentation tank 5 is transferred to the acid treatment tank 7, hydrochloric acid 14 is supplied to the acid treatment tank 7, the sediment of the titanium hydroxide aggregate and the hydrochloric acid 14 are mixed, and an acid treatment is performed. Next, a primary pressing step, a through washing step, and a secondary pressing step are performed on the acid-treated product of the titanium hydroxide aggregate using a filter press device 83 to wash the acid-treated product of the titanium hydroxide aggregate and remove the liquid phase, filter the acid-treated product of the titanium hydroxide aggregate, and obtain a press cake 24 of the acid-treated product of the titanium hydroxide aggregate.

[0101] The method for recovering the titanium component according to the second aspect of the present invention includes a titanium hydroxide agglomeration treatment step and an acid treatment step (B). The neutralization treatment, primary neutralization treatment, secondary neutralization treatment, and agglomeration treatment in the titanium hydroxide agglomeration treatment step according to the method for recovering the titanium component of the second aspect of the present invention are common to the method for recovering the titanium compound of the present invention, and for details thereof, it is the same as the description of the method for recovering the titanium component of the present invention.

[0102] In the acid treatment step (B) according to the method for recovering the titanium component of the second aspect of the present invention, after the titanium hydroxide agglomerate produced by performing the titanium hydroxide agglomeration treatment step is sedimented, hydrochloric acid or titanium chloride is brought into contact with the sediment of the obtained titanium hydroxide agglomerate to perform acid treatment on the titanium hydroxide agglomerate, and an acid-treated product of the titanium hydroxide agglomerate is obtained.

[0103] In the acid treatment step (B), the method for obtaining the sediment of the titanium hydroxide agglomerate from the agglomeration treatment liquid containing the titanium hydroxide agglomerate after performing the titanium hydroxide agglomeration treatment step is not particularly limited. For example, first, (i) the agglomeration treatment liquid containing the titanium hydroxide agglomerate after performing the titanium hydroxide agglomeration treatment is transferred to a sedimentation tank, and the titanium hydroxide agglomerate is sedimented in the sedimentation tank. Next, (ii) a method of extracting the sediment of the titanium hydroxide agglomerate from the lower part or bottom of the sedimentation tank and transferring the sediment of the titanium hydroxide agglomerate extracted from the sedimentation tank to an acid treatment tank can be mentioned.

[0104] Also, in the acid treatment step (B), as a method for obtaining the sediment of the titanium hydroxide agglomerate from the agglomeration treatment liquid containing the titanium hydroxide agglomerate after performing the titanium hydroxide agglomeration treatment step, a method of treating the agglomeration treatment liquid containing the titanium hydroxide agglomerate after performing the titanium hydroxide agglomeration treatment with a thickener, a liquid cyclone, a screw decanter, etc. to separate the aqueous phase from the agglomeration treatment liquid and obtaining the sediment of the titanium hydroxide agglomerate can be mentioned.

[0105] In the acid treatment step (B), then, hydrochloric acid or titanium chloride is brought into contact with the sediment of the titanium hydroxide agglomerate to perform acid treatment on the titanium hydroxide agglomerate, and a suspension of the acid-treated product of the titanium hydroxide agglomerate is obtained.

[0106] In the acid treatment according to the acid treatment step (B), hydrochloric acid or titanium chloride is brought into contact with the precipitate of titanium hydroxide aggregates. At this time, hydrochloric acid or titanium chloride is brought into contact so that 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. By the pH of the liquid phase during the acid treatment being within the above range, the calcium content in the titanium hydroxide aggregates 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 titanium hydroxide aggregates.

[0107] The acid used in the acid treatment according to the acid treatment step (B) is hydrochloric acid or titanium chloride.

[0108] The concentration of hydrochloric acid used in the acid treatment according to the acid treatment step (B) is not particularly limited, but is preferably 1.0 to 13.0 mol / L, more preferably 1.5 to 12.0 mol / L, and even more preferably 2.7 to 12.0 mol / L. By the concentration of hydrochloric acid used in the acid treatment being within the above range, the pH of the liquid phase during the acid treatment can be easily controlled within the desired range. When the concentration of hydrochloric acid used in the acid treatment exceeds the above range, it becomes difficult to control the pH of the liquid phase during the acid treatment, and when it is less than the above range, it becomes difficult to perform a smooth acid treatment.

[0109] The concentration of titanium chloride used in the acid treatment step (B) is not particularly limited, but the concentration of hydrochloric acid generated by hydrolysis is preferably 1.0 to 13.0 mol / L, more preferably 1.5 to 12.0 mol / L, and even more preferably 2.7 to 12.0 mol / L.

[0110] The temperature during the acid treatment according to the acid treatment step (B) 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.

[0111] In the acid treatment according to the acid treatment step (B), the contact time between the precipitate of titanium hydroxide aggregates and hydrochloric acid or titanium chloride is appropriately selected, preferably 10 minutes or more, more preferably 20 minutes or more, and even more preferably 30 minutes or more.

[0112] In the acid treatment step (B), as a method of performing the acid treatment, it is preferable to bring hydrochloric acid or titanium chloride into contact with the precipitate of titanium hydroxide aggregates in an acid treatment tank.

[0113] And by performing the acid treatment step (B), a suspension of the acid-treated product of titanium hydroxide aggregates is obtained.

[0114] In the titanium hydroxide aggregation treatment step and the acid treatment step (B) according to the method for recovering a titanium component in the second embodiment of the present invention, for the waste water containing a titanium compound, after hydrolysis treatment, calcium hydroxide is used as a neutralizing agent, and primary neutralization treatment, secondary neutralization treatment, and aggregation treatment are sequentially performed at a specific pH to produce and precipitate titanium hydroxide aggregates. By subjecting the precipitate of the obtained titanium hydroxide aggregates to an acid treatment in which hydrochloric acid or titanium chloride is brought into contact therewith, the calcium content in the titanium hydroxide aggregates obtained by performing the acid treatment can be reduced. Therefore, titanium hydroxide having a low calcium content can be recovered. In the titanium hydroxide aggregation treatment step and the acid treatment step (B) according to the method for recovering a titanium component in the second embodiment of the present invention, since the acid treatment step is performed on the precipitate obtained by precipitating the titanium hydroxide aggregates generated in the titanium hydroxide aggregation treatment step, 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 in the method for recovering a titanium component in the second embodiment of the present invention, titanium hydroxide having a low calcium content can be recovered.

[0115] In the method for recovering the titanium component of the present invention, the titanium hydroxide obtained by performing the secondary pressing step 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 drainage containing the titanium compound in the state of titanium hydroxide aggregates. Then, the recovered titanium hydroxide aggregates (acid-treated product) are converted into titanium oxide after drying and firing, and are used as a raw material for producing various titanium compounds.

[0116] In this way, in the method for recovering the titanium component of the present invention, the titanium compound in the drainage containing the titanium compound, preferably in the drainage containing the titanium compound generated when preparing the solid catalyst component for olefin polymerization or the catalyst for olefin polymerization, can be recovered as titanium hydroxide, and titanium hydroxide with a low calcium content and a low chlorine content can be easily recovered in a high yield.

[0117] According to the present invention, the following can be said. The present invention provides a filter press apparatus having a pressurized filtration chamber and a compression part provided inside the pressurized filtration chamber, having a filter membrane and filled with a material to be filtered. A suspension containing the acid-treated product of titanium hydroxide aggregates is sent into the space inside the compression part of the filter press apparatus, the compression part is filled with the suspension containing the acid-treated product of titanium hydroxide aggregates, and then the compression part and the suspension are pressed at 0.10 to 1.00 MPa by the pressurized filtration chamber to remove moisture from the suspension to obtain a primary pressed product of titanium hydroxide aggregates; a through-washing step of supplying washing water inside the pressurized filtration chamber and outside the compression part, flowing the washing liquid so as to penetrate the compression part and the primary pressed product of the acid-treated product of titanium hydroxide aggregates inside it, and performing through-washing on the primary pressed product of the acid-treated product of titanium hydroxide aggregates to obtain a through-washed product of the acid-treated product of titanium hydroxide aggregates; and a secondary pressing step of pressing the compression part and the through-washed product of the acid-treated product of titanium hydroxide aggregates by the pressurized filtration chamber to remove moisture from the through-washed product of the acid-treated product of titanium hydroxide aggregates to obtain a cake of the acid-treated product of titanium hydroxide aggregates. It is a method for recovering a titanium component, characterized by having these steps.

[0118] The inventors have found that when forward cleaning, which involves sending cleaning water from the same feed port that feeds the suspension containing the acid-treated product of titanium hydroxide aggregates to clean the suspension, is performed before the first pressing step, cracks occur in the suspension or cake containing the acid-treated product of titanium hydroxide aggregates. Once a crack occurs in the cake, the cleaning water flows intensively into the cracked part with low flow resistance, resulting in a significant decrease in the overall cleaning efficiency. Therefore, the inventors have found that by performing the first pressing step without forward cleaning and then cleaning the suspension (cake) containing the acid-treated product of titanium hydroxide aggregates by through cleaning, it is possible to prevent cracks from occurring in the suspension (cake) and improve the cleaning efficiency of the cake. As a result, the method for recovering the titanium component of the present invention can achieve higher cleaning efficiency and significantly reduce the chlorine content remaining in the cake of titanium hydroxide aggregates compared to the case where forward cleaning is performed.

[0119] Further, an exemplary embodiment of the present invention is a method for recovering a titanium component, characterized in that in the through cleaning step, the insertion pressure of the cleaning water is 0.10 to 0.60 MPa and the cleaning time is 17 to 60 minutes. According to this configuration, a sufficient cleaning effect of the cake can be obtained in the through cleaning step.

[0120] Also, an exemplary embodiment of the present invention is characterized in that the pressing pressure in the second pressing step is 0.10 to 1.00 MPa. According to this configuration, sufficient pressing and dehydration can be performed in the second pressing step.

[0121] Further, an exemplary embodiment of the present invention is a method for recovering a titanium component, characterized in that the pressing time in the second pressing step is longer than the pressing time in the first pressing step. According to this configuration, sufficient pressing and dehydration can be performed in the second pressing step.

[0122] Further, in the exemplary embodiment of the present invention, there is provided a method for recovering a titanium component, characterized in that the pressure of the washing water in the through-washing step is 0.10 to 0.60 MPa. According to this configuration, it is possible to prevent the cake from cracking, improve the washing efficiency, and significantly reduce the chlorine content remaining in the cake of titanium hydroxide aggregates.

[0123] Next, a method for producing titanium oxide according to the present invention will be described. The method for producing titanium oxide according to the present invention is a method for producing titanium oxide from a waste liquid containing a titanium compound, wherein the waste liquid containing the titanium compound is subjected to at least a hydrolysis treatment, a primary neutralization treatment using calcium hydroxide or calcium oxide as a neutralizing agent, a secondary neutralization treatment using calcium hydroxide or calcium oxide as a neutralizing agent, and a flocculation treatment for aggregating titanium hydroxide, thereby obtaining a titanium hydroxide aggregate in a titanium hydroxide aggregation treatment step; in a subsequent stage after the titanium hydroxide aggregation treatment step, an acid treatment is performed by bringing the titanium hydroxide aggregate into contact with hydrochloric acid or titanium chloride to obtain a suspension containing an acid-treated product of the titanium hydroxide aggregate in an acid treatment step; a suspension containing the acid-treated product of the titanium hydroxide aggregate is fed into a space inside the compression part of a filter press device having a pressurized filtration chamber and a compression part provided inside the pressurized filtration chamber, having a filtration membrane and filled with a material to be filtered, the compression part is filled with the suspension containing the acid-treated product of the titanium hydroxide aggregate, and then the compression part and the suspension are pressed at 0.10 to 1.00 MPa by the pressurized filtration chamber to remove moisture from the suspension, thereby obtaining a primary press cake of the acid-treated product of the titanium hydroxide aggregate in a primary pressing step; washing water is supplied inside the pressurized filtration chamber and outside the compression part, and a washing liquid is caused to flow through the compression part and the primary press cake of the acid-treated product of the titanium hydroxide aggregate inside it so as to penetrate the primary press cake of the acid-treated product of the titanium hydroxide aggregate, thereby performing through-washing of the primary press cake of the acid-treated product of the titanium hydroxide aggregate to obtain a through-washed product of the acid-treated product of the titanium hydroxide aggregate in a through-washing step; A secondary pressing step of pressing the compressed part and the through-washing product of the acid-treated product of the titanium hydroxide aggregate through the pressurized filtration chamber to remove moisture from the through-washing product of the acid-treated product of the titanium hydroxide aggregate to obtain a cake of the acid-treated product of the titanium hydroxide aggregate; A firing step of firing the acid-treated product of the titanium hydroxide aggregate after the secondary pressing step to obtain titanium oxide; It is characterized by having.

[0124] The method for producing titanium oxide of the present invention is the same as the method for recovering titanium compounds of the present invention in terms of the titanium hydroxide aggregation treatment step, acid treatment step, primary pressing step, through-washing step, secondary pressing step, etc., except that it has a firing step of firing the acid-treated product of the titanium hydroxide aggregate to obtain titanium oxide.

[0125] The firing step according to the method for producing titanium oxide of the present invention is a step of obtaining titanium oxide by firing the acid-treated product of the titanium hydroxide aggregate.

[0126] The firing conditions in the firing step are not particularly limited as long as the conditions under which titanium hydroxide is converted into titanium oxide are satisfied. For example, the firing temperature in the firing step is preferably 60 to 1300 °C. Also, the firing time is appropriately selected. Further, the firing atmosphere is an oxidizing atmosphere such as an air atmosphere or an oxygen gas atmosphere. Also, in the firing step, the firing may be performed only once, or the firing may be performed two or more times at the same temperature or different temperatures.

[0127] In the method for producing titanium oxide of the present invention, since the acid treatment step is performed on the titanium hydroxide aggregate obtained by performing the titanium hydroxide aggregation treatment step, when recovering the titanium component from the drainage containing the titanium compound to obtain titanium hydroxide, even if calcium hydroxide is used as the neutralizing agent, 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 content of chlorine in titanium oxide can be lowered by further performing the primary pressing step, the through-washing step, and the secondary pressing step.

[0128] Thus, in the method for producing titanium oxide of the present invention, the titanium compound in the drainage containing the titanium compound can be recovered as titanium oxide, and titanium oxide with a low calcium content and chlorine content can be easily recovered. Further, the amount of calcium hydroxide and / or calcium oxide used as the neutralizing agent can be reduced.

[0129] Next, the method for producing an alkali titanate of the present invention will be described. The method for producing an alkali titanate of the present invention is characterized in that titanium hydroxide (cake of the acid-treated product of the titanium hydroxide aggregate obtained by performing the secondary pressing step) recovered by the method for recovering a titanium component of the present invention, or titanium oxide obtained by performing the method for producing titanium oxide of the present invention is used as a raw material.

[0130] The method for producing an alkali titanate of the present invention can employ a known method except that titanium hydroxide (cake of the acid-treated product of the titanium hydroxide aggregate obtained by performing the secondary pressing step) recovered by the method for recovering a titanium component of the present invention, or titanium oxide obtained by performing the method for producing titanium oxide of the present invention is used as a raw material.

[0131] For example, when using titanium hydroxide (cake of the acid-treated product of titanium hydroxide aggregates obtained by performing the secondary pressing step) recovered by the method for recovering titanium components of the present invention as a titanium raw material, the titanium hydroxide (cake of the acid-treated product of titanium hydroxide aggregates obtained by performing the secondary pressing step) is oxidized by an appropriate method to be converted into titanium oxide, and then the obtained titanium oxide is used as a titanium raw material. As an alkali raw material, a potassium compound is used, and an alkali titanate can be produced by subjecting a raw material mixture containing both to a firing treatment and a pulverization treatment. Further, when using titanium oxide obtained by performing the method for producing titanium oxide of the present invention as a titanium raw material, the titanium oxide obtained by performing the method for producing titanium oxide of the present invention is used as a titanium raw material. As an alkali raw material, a potassium compound is used, and an alkali titanate can be produced by subjecting a raw material mixture containing both to a firing treatment and a pulverization treatment. In addition to potassium compounds, as the alkali raw material, compounds containing alkali metals such as lithium compounds, sodium compounds, rubidium compounds, cesium compounds, and francium compounds, and compounds containing alkaline earth metals such as magnesium compounds, barium compounds, and calcium compounds can also be applied.

[0132] The obtained alkali titanate is suitably used, for example, as a friction material for friction sliding members such as brake linings, disk pads, and clutch facings, which constitute braking devices in automobiles, railway vehicles, aircraft, and industrial machines.

[0133] For example, when using the alkali titanate obtained by the method for producing an alkali titanate of the present invention as a material for a brake friction material, the alkali titanate is 15 to 25% by mass, the phenolic resin is 9 to 11% by mass, graphite (artificial graphite) is 7 to 9% by mass, barium sulfate (barite) is 25 to 30% by mass, zirconium silicate is 6 to 8% by mass, antimony trisulfide is 2 to 4% by mass, copper fiber and powder are 0 to 9% by mass, cashew dust is 4 to 6% by mass, rubber powder is 1 to 3% by mass, aramid fiber is 3 to 5% by mass, mica is 4 to 6% by mass, and chromite is 0 to 2% by mass. A raw material mixture for a friction material is formed into the shape of a brake friction material, and the surface pressure is 10 to 400 kgf / cm 2 , and it is pressurized at a temperature of 70 to 250 °C by hot forming to obtain a brake friction material.

[0134] According to the method for producing an alkali titanate of the present invention, since a high-purity titanium compound with a low calcium content obtained from the titanium compound-containing drainage generated when preparing a solid catalyst component for olefin polymerization or a catalyst for olefin polymerization is used as a raw material, a high-purity alkali titanate can be produced at low cost.

[0135] Metallic titanium is obtained through the following steps. Using natural rutile, synthetic rutile, and high-purity slag, which are high-purity titanium oxide raw materials, as raw materials, titanium oxide is chlorinated in a chlorination furnace to produce titanium tetrachloride. Next, titanium tetrachloride is reduced with metallic magnesium in a sealed container to produce a sponge titanium mass. The sponge titanium mass is extruded from the container using a high-pressure cylinder, cut and crushed according to the quality of the mass part to obtain sponge titanium crushed material. In order to use titanium for various metal material applications, it is necessary to dissolve and roll the sponge titanium crushed material and purify an ingot of 1 to 15 t according to the application. Thus, titanium oxide becomes, for example, a titanium tetrachloride raw material. That is, titanium oxide is a raw material for producing titanium tetrachloride by chlorination of titanium oxide.

[0136] The titanium hydroxide obtained by performing the method for recovering the titanium component of the present invention (the cake of the acid-treated product of the titanium hydroxide aggregate obtained by performing the secondary pressing step) becomes titanium oxide having appropriate hardness by firing at a predetermined temperature, and the titanium oxide can be used as a raw material for producing titanium tetrachloride. The firing temperature when firing the titanium hydroxide aggregate is 1100 ° C or higher, preferably 1200 ° C or higher. The upper limit of the firing temperature is not particularly limited, but for example, it is appropriately selected in the range of 1200 to 1300 ° C, and the firing temperature is, for example, 1300 ° C or lower. When the firing temperature is less than 1100 ° C, it does not become titanium oxide having appropriate hardness, which is not preferable. Here, the hardness of titanium oxide means the hardness that can maintain a particle size that can stay in the fluidized bed and be subjected to chlorination treatment after charging a titanium tetrachloride raw material (about 2t in general) into a chlorination furnace (fluidized bed). Specifically, the hardness of titanium oxide is 10.0 N / mm 2 (1000 gf / mm 2 ) or more, preferably 20.0 N / mm 2 (2000 gf / mm 2 ) or more. The upper limit of the hardness of the titanium oxide is not particularly limited, but for example, 20.0 N / mm 2 (2000 gf / mm 2 ) or more and 50.0 N / mm 2 (5000 gf / mm 2 ) or less. When the hardness of the titanium oxide is less than 10.0 N / mm 2 (1000 gf / mm 2 ), it is not preferable because it is not possible to maintain a particle size that can stay in the fluidized bed and be subjected to chlorination treatment. In the present invention, the firing atmosphere is not particularly limited. For example, it may be fired in an oxidizing atmosphere such as an air atmosphere or an oxygen gas atmosphere. Further, the firing may be performed only once, or the firing may be performed two or more times at the same temperature or different temperatures.

[0137] That is, the method for producing a titanium tetrachloride raw material according to the present invention is a method for obtaining titanium oxide, which is a raw material for producing titanium tetrachloride, using titanium hydroxide (cake of the acid-treated product of the titanium hydroxide aggregate obtained by performing the secondary pressing step) recovered by the method for recovering a titanium component of the present invention as a raw material. Titanium hydroxide (cake of the acid-treated product of the titanium hydroxide aggregate obtained by performing the secondary pressing step) recovered by the method for recovering a titanium component of the present invention is calcined at 1100 ° C or higher in an oxidizing atmosphere to obtain titanium oxide, which is a raw material for producing titanium tetrachloride. The calcination temperature when calcining titanium hydroxide recovered by the method for recovering a titanium component of the present invention is preferably 1200 ° C or higher. The upper limit of the calcination temperature is not particularly limited, but is appropriately selected, for example, in the range of 1200 to 1300 ° C, and the calcination temperature is, for example, 1300 ° C or lower.

Example

[0138] Next, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited by the following examples.

[0139] According to the flowcharts shown in FIGS. 1 and 2, the titanium component was recovered. As the filter press apparatus for performing the flow of FIG. 2, a Krit type HJMF-2B-A manufactured by Kurita Machinery Works was used.

[0140] (Production Example 1) <Preparation of Suspension of Acid-Treated Product of Titanium Hydroxide Aggregate> In a Ziegler-Natta catalyst production plant, the drainage liquid at a liquid temperature of 25 ° C containing titanium tetrachloride, diethoxymagnesium, toluene and heptane generated when preparing a solid catalyst component for olefin polymerization was used as the treatment target, and the drainage liquid was placed in a receiving tank 1 with a capacity of 250 m 3 was fed into and mixed, and hydrolysis was performed. At this time, water 11 for hydrolysis was fed into the receiving tank so that the pH of the drainage liquid in the receiving tank became 1. The above hydrolysis-treated liquid was added at a rate of 10 m 3 / h to a capacity of 10 m 3It was fed into the primary neutralization treatment tank 2, and primary neutralization treatment was carried out using a 12.5 mol / L calcium hydroxide aqueous solution at a liquid temperature of 25°C so that the pH of the treatment liquid fed into the primary neutralization treatment tank 2 became 2.0. Next, the treatment liquid that had undergone the above primary neutralization treatment was fed into a secondary neutralization treatment tank 3 with a volume of 10 m 3 at a rate of 10 m / h, and secondary neutralization treatment was carried out using a 12.5 mol / L calcium hydroxide aqueous solution at a liquid temperature of 25°C so that the pH of the treatment liquid fed into the secondary neutralization treatment tank 3 became 7.2. 3 The treatment liquid at a liquid temperature of 25°C that had undergone secondary neutralization treatment was fed into a coagulation tank 4 with a volume of 10 m at a rate of 10 m / h, and coagulated using a coagulant (Clifarm PA-833 manufactured by Krita Chemical Hokuriku Co., Ltd.) to obtain a coagulated treatment liquid. Then, the coagulated treatment liquid was transferred to a 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 was transferred to a sediment storage tank 6. 3 Next, the sediment was fed into an acid treatment tank 7, diluted with ion-exchanged water, and then hydrochloric acid 14 was supplied to the acid treatment tank 7 so that the pH of the obtained liquid phase became 5.0. The titanium hydroxide aggregate and hydrochloric acid 14 were mixed and acid treatment was carried out to obtain a suspension of the acid-treated product of the titanium hydroxide aggregate. 3 (Example 1) Then, the sediment was fed into an acid treatment tank 7, diluted with ion-exchanged water, and then hydrochloric acid 14 was supplied to the acid treatment tank 7 so that the pH of the obtained liquid phase became 5.0. The titanium hydroxide aggregate and hydrochloric acid 14 were mixed and acid treatment was carried out to obtain a suspension of the acid-treated product of the titanium hydroxide aggregate.

[0141] (Example 1) According to the processing flow shown in FIG. 1, the space in the compression part of the filter press device was filled with a suspension of the acid-treated product of titanium hydroxide aggregates sent from the acid treatment tank 7. In Example 1, without performing forward washing on the suspension of the acid-treated product of titanium hydroxide aggregates, the diaphragm was driven to advance the squeezing membrane toward the compression part, and the suspension of the acid-treated product of titanium hydroxide aggregates in the compression part was subjected to primary squeezing. The primary squeezing was performed at a pressure of 0.68 MPa for a squeezing time of 3 minutes. Next, after releasing the primary squeezing, the primary squeezed product in the compression part squeezed by the primary squeezing was subjected to through washing using washing water composed of water. The through washing was performed by injecting the washing water at a pressure of 0.36 MPa for 22 minutes. Next, the diaphragm was driven to advance the squeezing membrane toward the compression part, and the through-washed product in the compression part was subjected to secondary squeezing. The secondary squeezing was performed at a pressure of 0.68 MPa for a squeezing time of 10 minutes. After releasing the secondary squeezing, a press cake of the acid-treated product of titanium hydroxide aggregates was obtained by taking it out from the compression part.

[0142] The Cl content in the press cake was analyzed by elemental quantification by the FP method using a fluorescent X-ray analyzer (EDXL300 manufactured by Rigaku Corporation). The content of Cl in atomic conversion remaining in the press cake was 0.10 mass% or less. The analysis results are shown below.

[0143] (Example 2) In accordance with the processing flow shown in FIG. 1, the space in the compression section of the filter press device was filled with a suspension of the acid-treated product of titanium hydroxide aggregates sent from the acid treatment tank 7. In Example 2, without performing forward washing on this suspension of the acid-treated product of titanium hydroxide aggregates, the diaphragm was driven to advance the pressing membrane toward the compression section, and the suspension of the acid-treated product of titanium hydroxide aggregates in the compression section was subjected to primary pressing. The primary pressing was performed at a pressure of 0.68 MPa for a pressing time of 3 minutes. Next, after releasing the primary pressing, the primary pressed product in the compression section pressed by the primary pressing was subjected to through washing using washing water composed of water. The through washing was performed by injecting the washing water at a pressure of 0.36 MPa for 25 minutes. Next, the diaphragm was driven to advance the pressing membrane toward the compression section, and the through washed product in the compression section was subjected to secondary pressing. The secondary pressing was performed at a pressure of 0.68 MPa for a pressing time of 7 minutes. After releasing the secondary pressing, a press cake of the acid-treated product of titanium hydroxide aggregates was obtained by taking it out from the compression section.

[0144] The Cl content in the press cake was analyzed. The Cl content in terms of atoms remaining in the press cake was 0.10 mass% or less.

[0145] (Example 3) According to the processing flow shown in FIG. 1, the space in the compression part of the filter press device was filled with a suspension of the acid-treated product of titanium hydroxide aggregates sent from the acid treatment tank 7. In Example 3, without performing forward washing on the suspension of the acid-treated product of titanium hydroxide aggregates, the diaphragm was driven to advance the pressing membrane toward the compression part, and the suspension of the acid-treated product of titanium hydroxide aggregates in the compression part was subjected to primary pressing. The primary pressing was performed at a pressure of 0.68 MPa for a pressing time of 3 minutes. Then, after releasing the primary pressing, the primary pressed product in the compression part pressed by the primary pressing was subjected to through washing using washing water composed of water. The through washing was performed by injecting the washing water at a pressure of 0.36 MPa for 20 minutes. Then, the diaphragm was driven to advance the pressing membrane toward the compression part, and the through washed product in the compression part was subjected to secondary pressing. The secondary pressing was performed at a pressure of 0.68 MPa for a pressing time of 10 minutes. After releasing the secondary pressing, a press cake of the acid-treated product of titanium hydroxide aggregates was obtained by taking it out from the compression part.

[0146] The Cl content in the press cake was analyzed. The Cl content in terms of atoms remaining in the press cake was 0.10% by mass.

[0147] (Comparative Example 1) According to the processing flow shown in Fig. 1, the space in the compression part of the filter press device was filled with a suspension of the acid-treated product of titanium hydroxide aggregates sent from the acid treatment tank 7. In Comparative Example 1, positive washing was performed on this suspension of the acid-treated product of titanium hydroxide aggregates. The positive washing was carried out by injecting washing water at a pressure of 0.36 MPa for 10 minutes. Then, the diaphragm was driven to advance the pressing membrane toward the compression part, and the suspension of the acid-treated product of titanium hydroxide aggregates in the compression part was subjected to primary pressing. The primary pressing was carried out at a pressure of 0.68 MPa for a pressing time of 5 minutes. Then, after releasing the primary pressing, through washing was performed on the primary pressed product in the compression part pressed by the primary pressing using washing water composed of water. The through washing was carried out by injecting washing water at a pressure of 0.36 MPa for 5 minutes. Then, the diaphragm was driven to advance the pressing membrane toward the compression part, and the through-washed product in the compression part was subjected to secondary pressing. The secondary pressing was carried out at a pressure of 0.68 MPa for a pressing time of 15 minutes. After releasing the secondary pressing, a press cake of the acid-treated product of titanium hydroxide aggregates was obtained by taking it out from the compression part.

[0148] The Cl content in the press cake was analyzed. The Cl content in terms of atoms remaining in the press cake was 0.50% by mass.

[0149] (Comparative Example 2) According to the processing flow shown in Fig. 1, the space in the compression part of the filter press device was filled with a suspension of the acid-treated product of titanium hydroxide aggregates sent from the acid treatment tank 7. In Comparative Example 2, positive cleaning was performed on the suspension of the acid-treated product of titanium hydroxide aggregates. The positive cleaning was carried out by injecting cleaning water at a pressure of 0.36 MPa for 5 minutes. Then, the diaphragm was driven to advance the pressing membrane toward the compression part, and the suspension of the acid-treated product of titanium hydroxide aggregates in the compression part was subjected to primary pressing. The primary pressing was carried out at a pressure of 0.68 MPa for a pressing time of 5 minutes. Then, after the release of the primary pressing, the primary pressed product in the compression part pressed by the primary pressing was subjected to through cleaning using cleaning water composed of water. The through cleaning was carried out by injecting cleaning water at a pressure of 0.36 MPa for 10 minutes. Then, the diaphragm was driven to advance the pressing membrane toward the compression part, and the through-cleaned product in the compression part was subjected to secondary pressing. The secondary pressing was carried out at a pressure of 0.68 MPa for a pressing time of 15 minutes. After the release of the secondary pressing, the press cake of the acid-treated product of titanium hydroxide aggregates was obtained by taking it out from the compression part.

[0150] The Cl content in the press cake was analyzed. The Cl content in atomic conversion remaining in the press cake was 0.60% by mass.

[0151] (Comparative Example 3) In accordance with the processing flow shown in FIG. 1, the space in the compression section of the filter press device was filled with a suspension of the acid-treated product of titanium hydroxide aggregates sent from the acid treatment tank 7. In Comparative Example 3, forward washing was performed on this suspension of the acid-treated product of titanium hydroxide aggregates. The forward washing was carried out by injecting washing water at a pressure of 0.36 MPa for 1 minute. Next, the diaphragm was driven to advance the pressing membrane toward the compression section, and the suspension of the acid-treated product of titanium hydroxide aggregates in the compression section was subjected to primary pressing. The primary pressing was performed at a pressure of 0.68 MPa for a pressing time of 3 minutes. Next, after releasing the primary pressing, through washing was performed on the primary pressed product in the compression section pressed by the primary pressing using washing water composed of water. The through washing was carried out by injecting washing water at a pressure of 0.36 MPa for 16 minutes. Next, the diaphragm was driven to advance the pressing membrane toward the compression section, and the through-washed product in the compression section was subjected to secondary pressing. The secondary pressing was performed at a pressure of 0.68 MPa for a pressing time of 15 minutes. After releasing the secondary pressing, a press cake of the acid-treated product of titanium hydroxide aggregates was obtained by taking it out from the compression section.

[0152] The Cl content in the press cake was analyzed. The Cl content in terms of atoms remaining in the press cake was 0.60% by mass.

[0153] (Comparative Example 4) According to the processing flow shown in Fig. 1, the space in the compression part of the filter press device was filled with a suspension of the acid-treated product of titanium hydroxide aggregates sent from the acid treatment tank 7. In Comparative Example 4, forward washing was performed on this suspension of the acid-treated product of titanium hydroxide aggregates. The forward washing was carried out by injecting washing water at a pressure of 0.36 MPa for 1 minute. Then, the diaphragm was driven to advance the pressing membrane toward the compression part, and the suspension of the acid-treated product of titanium hydroxide aggregates in the compression part was subjected to primary pressing. The primary pressing was performed at a pressure of 0.68 MPa for a pressing time of 5 minutes. Then, after releasing the primary pressing, the primary pressed product in the compression part pressed by the primary pressing was subjected to through washing using washing water composed of water. The through washing was carried out by injecting washing water at a pressure of 0.36 MPa for 1 minute. Then, the diaphragm was driven to advance the pressing membrane toward the compression part, and the through-washed product in the compression part was subjected to secondary pressing. The secondary pressing was performed at a pressure of 0.68 MPa for a pressing time of 15 minutes. After releasing the secondary pressing, a press cake of the acid-treated product of titanium hydroxide aggregates was obtained by taking it out from the compression part.

[0154] The Cl content in the press cake was analyzed. The Cl content remaining in the press cake in terms of the original conversion was 1.2 mass%.

[0155] (Comparative Example 5) In accordance with the processing flow shown in FIG. 1, the space inside the compression part of the filter press device was filled with a suspension of the acid-treated product of titanium hydroxide aggregates sent from the acid treatment tank 7. In Comparative Example 5, a positive cleaning was performed on this suspension of the acid-treated product of titanium hydroxide aggregates. The positive cleaning was carried out by injecting cleaning water at a pressure of 0.36 MPa for 2 minutes. Next, the diaphragm was driven to advance the squeezing membrane toward the compression part, and the suspension of the acid-treated product of titanium hydroxide aggregates inside the compression part was subjected to primary squeezing. The primary squeezing was performed at a pressure of 0.68 MPa for a squeezing time of 1 minute. Next, after the release of the primary squeezing, the primary squeezed product inside the compression part that had been squeezed in the primary squeezing was subjected to through washing using cleaning water composed of water. The through washing was carried out by injecting cleaning water at a pressure of 0.36 MPa for 20 minutes. Next, the diaphragm was driven to advance the squeezing membrane toward the compression part, and the through-washed product inside the compression part was subjected to secondary squeezing. The secondary squeezing was performed at a pressure of 0.68 MPa for a squeezing time of 12 minutes. After the release of the secondary squeezing, a press cake of the acid-treated product of titanium hydroxide aggregates was obtained by taking it out from inside the compression part.

[0156] The Cl content in the press cake was analyzed. The content of Cl in atomic conversion remaining in the press cake was 1.0% by mass.

[0157]

Table 1

[0158] In Examples 1 to 3, since the through-washing step was performed after the primary pressing step without performing the forward washing, the suspension (cake) of the acid-treated product of the titanium hydroxide aggregates could be aggregated and compression-molded in advance, and thereby it is presumed that the suspension (cake) of the acid-treated product of the titanium hydroxide aggregates did not crack during the through-washing. As a result, it is presumed that the washing efficiency as a whole of the cake in the through-washing was improved and the Cl concentration in the press cake was significantly decreased. On the other hand, in Comparative Examples 1 to 5, since the forward washing was performed before the primary pressing step, there is a high possibility that the suspension (cake) of the acid-treated product of the titanium hydroxide aggregates cracked during the forward washing, and thereby it is presumed that the washing water concentratedly flowed into the cracked portion during the through-washing and the washing efficiency as a whole of the cake was decreased. As a result, it is presumed that the Cl content in the press cake in Comparative Examples 1 to 5 did not sufficiently decrease.

[0159] (Example 4) The press cake of the acid-treated product of the titanium hydroxide aggregates obtained in Example 1 was heat-treated at 850°C for 2 hours in an air atmosphere using a shuttle kiln, and then further heat-treated at 950°C for 2 hours to obtain the target titanium oxide. When the crystal structures of the obtained titanium hydroxide and titanium oxide were measured using an X’PERT-PRO-MPD multi-purpose X-ray diffractometer (manufactured by PANalytical), it was confirmed that the obtained titanium hydroxide contained a small amount of rutile-type titanium oxide but the main crystal system was amorphous, whereas the titanium oxide was of the rutile type.

[0160] (Example 5) 52.16 kg of the titanium oxide obtained in Example 4, 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 filled into a vibration rod mill (manufactured by Chuo Kako Co., Ltd.), and further 0.6 kg of a lower alcohol was 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 1200 °C at a flow rate of 17.5 kg / hr. In this rotary kiln, a synthesis reaction to potassium titanate occurred, and the fired product was discharged from the rotary kiln. The discharged fired product was rapidly cooled to room temperature. Subsequently, the cooled fired product was pulverized with a vibration rod mill (manufactured by Chuo Kakoki Co., Ltd.), and then pulverized with an impact pulverizer (ACM Pulverizer, manufactured by Hosokawa Micron Corporation) equipped with a classifier to obtain potassium titanate particles. The physical properties of the obtained potassium titanate particles are shown in Table 2. Also, the XRD measurement results are shown in Figure 7, and the SEM observation results are shown in Figure 8, respectively. For comparison, Table 2 also shows the physical properties of commercially available potassium titanate particles (manufactured by Toho Titanium Co., Ltd., TOFIX-SNR-S). Also, the SEM observation results are shown in Figure 9. The measuring devices or measuring methods used for measuring each physical property are as follows. ≪Measuring Devices≫ XRD: X’PERT-PRO-MPD multi-purpose X-ray diffractometer (manufactured by PANalytical) SEM: Scanning electron microscope, JSM-7800 (manufactured by JEOL Ltd.) Specific surface area: Specific surface area meter, monosorb (manufactured by Quantacrome)

[0161]

Table 2

[0162] As shown in Table 2, it was confirmed that the potassium titanate particles of Example 5 had the same phase composition and powder shape as the commercially available product. Also, regarding the specific surface area, it was within the standard value of the commercially available product (standard value: 2.0 - 3.0 m 2 / g).

[0163] (Example 6) 52.16 kg of titanium oxide obtained in Example 4, 52.23 kg of titanium ore, 24.65 kg of sodium carbonate powder, 2.87 kg of titanium powder, and 5.70 kg of wood chips (wood pellets) were filled into a vibration rod mill (manufactured by Chuo Kako Co., Ltd.), and 0.6 kg of lower alcohol was further added thereto, followed by treatment at an amplitude of 5 mm for 15 minutes to obtain a raw material mixture. Sodium titanate particles were obtained in the same manner as in Example 5, except that approximately 140 kg of the above raw material mixture was supplied to a rotary kiln at a temperature of 1200°C at a flow rate of 17.5 kg / hr. The physical properties of the obtained sodium titanate particles are shown in Table 3. The XRD measurement results are shown in Figure 10. For comparison, Table 3 also shows the physical properties of commercially available sodium titanate particles (manufactured by Toho Titanium Co., Ltd., TOFIX-NTO). The measuring apparatus or measuring method used for measuring each physical property is the same as in Example 5.

[0164]

Table 3

[0165] As shown in Table 3, it was confirmed that the sodium titanate particles of Example 6 had the same phase composition and powder shape as the commercially available product. Also, regarding the specific surface area, it was within the standard value of the commercially available product (standard value: 2.5 to 4.5 m 2 / g).

[0166] (Example 7) 52.16 kg of titanium oxide obtained in Example 4, 52.23 kg of titanium ore, 275.40 kg of barium carbonate powder, 2.87 kg of titanium powder, and 5.70 kg of wood chips (wood pellets) were filled into a vibration rod mill (manufactured by Chuo Kakoki Co., Ltd.), and 0.6 kg of lower alcohol was further added thereto, followed by treatment at an amplitude of 5 mm for 15 minutes to obtain a raw material mixture. Barium titanate particles were obtained in the same manner as in Example 5, except that approximately 390 kg of the above raw material mixture was supplied to a rotary kiln at a temperature of 1,200°C at a flow rate of 17.5 kg / hr. The physical properties of the obtained barium titanate particles are shown in Table 4. The XRD measurement results are shown in FIG. 11. The measuring apparatus or measuring method used for measuring each physical property is the same as in Example 5.

[0167] (Example 8) 52.16 kg of titanium oxide obtained in Example 4, 52.23 kg of titanium ore, 139.68 kg of calcium carbonate powder, 2.87 kg of titanium powder, and 5.70 kg of wood chips (wood pellets) were filled into a vibration rod mill (manufactured by Chuo Kakoki Co., Ltd.), and 0.6 kg of lower alcohol was further added thereto, followed by treatment at an amplitude of 5 mm for 15 minutes to obtain a raw material mixture. Calcium titanate particles were obtained in the same manner as in Example 5, except that approximately 250 kg of the above raw material mixture was supplied to a rotary kiln at a temperature of 1,200°C at a flow rate of 17.5 kg / hr. The physical properties of the obtained calcium titanate particles are shown in Table 4. The XRD measurement results are shown in FIG. 12. The measuring apparatus or measuring method used for measuring each physical property is the same as in Example 5.

[0168]

Table 4

[0169] (Example 9) A friction material was produced using the alkali titanate (6 potassium titanate; 6KTO) obtained in Example 5. As a friction material raw material, together with the alkali titanate produced in Example 5, phenol resin, artificial graphite, barium sulfate, zirconium silicate, antimony trisulfide, copper fiber, copper powder, cashew dust, rubber powder, aramid fiber, mica, and chromite ore were mixed at the mixing ratios shown in Table 5 to obtain a mixed powder of friction material raw materials. The obtained mixed powder of friction material raw materials was preformed at 200 kgf / cm 2 and the obtained preform was preheated at 70 °C for 2 hours, then hot formed at 180 °C and 400 kgf / cm 2 and then heat treated at 250 °C and 10 kgf / cm 2 for 3 hours to obtain a formed body, and a friction material with a length of 10 mm, a width of 50 mm, and a thickness of 10 mm was obtained from the obtained formed body.

[0170] <Brake Test> Regarding the friction material obtained in Example 9, the friction coefficient of the friction material was measured in accordance with JASO-C406, which is a standard of the Japan Society of Automotive Engineers. The average value of the friction coefficient in the second fade test of the second fade recovery test was 0.36.

[0171]

Table 5

[0172] (Comparative Example 6, Examples 10 to 12) The press cake of the acid-treated product of the titanium hydroxide aggregate obtained in Example 1 was dried at 120 °C for 16 hours in an air atmosphere using a constant temperature dryer (manufactured by Yamato Scientific Co., Ltd., DX602), then lightly crushed, and heat treated in an air atmosphere at the firing temperature shown in Table 6 for 10 minutes using an MS electric furnace (Motoyama Co., Ltd., SC-2035D-SP), and sieved (mesh opening 500 - 710 μm) to obtain the target titanium oxide. The obtained titanium oxide was measured for hardness using a fully automatic granular hardness tester "Better Hardness Tester" (manufactured by Seishin Enterprise Co., Ltd., BHT-500). The results are shown in Table 6. Note that the oil coke in Table 6 is the softest among the raw materials charged into the fluidized bed in the production of general titanium chloride, and it is described in order to use this hardness as a reference value. From the hardness of the oil coke, those suitable as the hardness of the titanium oxide of the present invention are 10.0 N / mm 2 (1000 gf / mm 2 ) or more, preferably 20.0 N / mm 2 (2000 gf / mm 2 ) or more. "◎: 20.0 Nmm 2 or more, suitable, good hardness", "〇: 10.0 Nmm 2 or more and less than 20.0 Nmm 2 , suitable", "×: 10.0 Nmm 2 less than, unsuitable" was noted.

[0173]

Table 6

Explanation of Symbols

[0174] 1 Water receiving tank 2 Primary neutralization treatment tank 3 Secondary neutralization treatment tank 4 Coagulation tank 5 Sedimentation tank 6 Sediment storage tank 7 Acid treatment tank 8, 81, 82, 83 Filter press device 10 Drainage containing titanium compound 11 Water 12, 13 Calcium hydroxide suspension 14 Hydrochloric acid 20, 21, 24 Press cake of acid-treated product of titanium hydroxide aggregate 31 Filtration chamber 32 Filter membrane 33 Filter plate 34 Squeezing membrane 36 Compression part

Claims

1. A method for recovering a titanium component from a drainage containing a titanium compound, comprising: subjecting the drainage containing the titanium compound to at least a hydrolysis treatment, a primary neutralization treatment using calcium hydroxide or calcium oxide as a neutralizing agent, a secondary neutralization treatment using calcium hydroxide or calcium oxide as a neutralizing agent, and a flocculation treatment for aggregating titanium hydroxide, thereby obtaining a titanium hydroxide aggregate in a titanium hydroxide flocculation treatment step; in a subsequent stage from the titanium hydroxide flocculation treatment step, performing an acid treatment in which hydrochloric acid or titanium chloride is brought into contact with the titanium hydroxide aggregate to obtain a suspension containing an acid-treated product of the titanium hydroxide aggregate in an acid treatment step; feeding the suspension containing the acid-treated product of the titanium hydroxide aggregate into a space inside the compression part of a filter press device having a pressurized filtration chamber and a compression part provided inside the pressurized filtration chamber, having a filtration membrane and filled with a material to be filtered, filling the compression part with the suspension containing the acid-treated product of the titanium hydroxide aggregate, and then, without performing a forward wash, squeezing the compression part and the suspension at 0.10 to 1.00 MPa by the pressurized filtration chamber to remove moisture from the suspension and obtaining a primary squeezed product of the acid-treated product of the titanium hydroxide aggregate in a primary squeezing step; supplying washing water inside the pressurized filtration chamber and outside the compression part, flowing the washing liquid so as to penetrate the compression part and the primary squeezed product of the acid-treated product of the titanium hydroxide aggregate inside thereof, performing a through-washing of the primary squeezed product of the acid-treated product of the titanium hydroxide aggregate, and obtaining a through-washed product of the acid-treated product of the titanium hydroxide aggregate in a through-washing step; squeezing the compression part and the through-washed product of the acid-treated product of the titanium hydroxide aggregate by the pressurized filtration chamber to remove moisture from the through-washed product of the acid-treated product of the titanium hydroxide aggregate and obtaining a cake of the acid-treated product of the titanium hydroxide aggregate in a secondary squeezing step; A method for recovering a titanium component, characterized by comprising the above steps.

2. The method for recovering a titanium component according to claim 1, characterized in that in the through-washing step, the insertion pressure of the washing water is 0.10 to 0.60 MPa and the washing time is 17 to 60 minutes.

3. The method for recovering a titanium component according to claim 1, wherein the pressing pressure in the secondary pressing step is 0.10 to 1.00 MPa.

4. The method for recovering a titanium component according to claim 1, wherein the pressing time in the secondary pressing step is longer than the pressing time in the primary pressing step.

5. The method for recovering a titanium component according to claim 1, wherein the pressure of the washing water in the through-washing step is 0.10 to 0.60 MPa.

6. A method for producing titanium oxide from a drainage containing a titanium compound, comprising: a titanium hydroxide agglomeration treatment step of obtaining a titanium hydroxide agglomerate by performing at least a hydrolysis treatment, a primary neutralization treatment using calcium hydroxide or calcium oxide as a neutralizing agent, a secondary neutralization treatment using calcium hydroxide or calcium oxide as a neutralizing agent, and an agglomeration treatment for agglomerating titanium hydroxide on the drainage containing the titanium compound; an acid treatment step of performing an acid treatment of bringing hydrochloric acid or titanium chloride into contact with the titanium hydroxide agglomerate at a stage subsequent to the titanium hydroxide agglomeration treatment step to obtain a suspension containing an acid-treated product of the titanium hydroxide agglomerate; a primary pressing step of feeding the suspension containing the acid-treated product of the titanium hydroxide agglomerate into a space inside a compression part of a filter press device having a pressurized filtration chamber and a compression part provided inside the pressurized filtration chamber, having a filtration membrane and filled with a material to be filtered, filling the compression part with the suspension containing the acid-treated product of the titanium hydroxide agglomerate, and then pressing the compression part and the suspension at 0.10 to 1.00 MPa by the pressurized filtration chamber to remove moisture from the suspension to obtain a primary pressed product of the acid-treated product of the titanium hydroxide agglomerate without performing positive washing; Supply cleaning water inside the pressurized filtration chamber and outside the compression part, and flow the cleaning liquid so as to penetrate the compression part and the primary press cake of the acid-treated product of the titanium hydroxide agglomerates therein, thereby performing through-washing on the primary press cake of the acid-treated product of the titanium hydroxide agglomerates to obtain a through-washed product of the acid-treated product of the titanium hydroxide agglomerates; a through-washing step Pressurize the compression part and the through-washed product of the acid-treated product of the titanium hydroxide agglomerates by the pressurized filtration chamber to remove moisture from the through-washed product of the acid-treated product of the titanium hydroxide agglomerates to obtain a cake of the acid-treated product of the titanium hydroxide agglomerates; a secondary pressing step After performing the secondary pressing step, bake the acid-treated product of the titanium hydroxide agglomerates to obtain titanium oxide; a baking step A method for producing titanium oxide, characterized by comprising the above steps.

7. A method for producing an alkali titanate, characterized by using titanium hydroxide recovered by the method for recovering a titanium component according to Claim 1 or titanium oxide obtained by the method for producing titanium oxide according to Claim 6 as a raw material.

8. A method for producing a friction material, characterized by using the alkali titanate obtained by the method for producing an alkali titanate according to Claim 7 as a raw material.

9. A method for producing a titanium tetrachloride raw material, characterized by using titanium hydroxide recovered by the method for recovering a titanium component according to Claim 1 as a raw material.

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