JP2702200B2 - Method for producing titanium oxide - Google Patents

Description

The present invention relates to the production of titanium oxide.

BACKGROUND OF THE INVENTION When producing titanium dioxide by the sulfuric acid method, it is known to raise the temperature of ilmenite materials such as ilmenite (ilmenite, anatase) or titanium slag. In addition to obtaining mainly ferrous sulfate, ferric sulfate and titanyl sulfate by contacting with sulfuric acid which is high in area and concentrated, it consists of magnesium sulfate, chromium sulfate, manganese sulfate, vanadium sulfate and sulfates of other elements In addition, a solid containing predominantly titanyl sulfate containing unreacted substances is produced. Next, this solid is poured into water or a sulfuric acid solution, and a reducing agent such as iron scrap is added to the leached sulfuric acid solution to convert ferric sulfate in the solution to ferrous sulfate. By further cooling the solution, crystals of ferrous sulfate (FeSO ₄ .7H ₂ O) are precipitated, and the iron content in the solution is reduced to produce a titanium iron solution containing titanyl sulfate.

In the hydrolysis method of titanyl sulfate, a high-concentration titanyl sulfate was added to a low-concentration titanyl sulfate kept almost in a boiling state, and after gradually increasing the titanyl sulfate-iron solution concentration,
This is done by adding about 1/4 of the water to 90-95 ° C. elevated water. Although the total sulfuric acid concentration of the aqueous solution after hydrolysis is slight density difference by operating 35g / ~400g / H ₂ SO
₄ , 4-6% titanyl sulfate is present in the solution, while 94-95% of the titanyl sulfate precipitates with the hydroxide;
There was a drawback that titanium hydroxide could not be used and was discarded.

[Means for Solving the Problems] The object of the present invention is to provide a solution obtained by extracting the sulfate complex of titanium according to the present invention according to claim 1 and then back-extracting with water or dilute sulfuric acid to obtain titanyl sulfate. Repeatedly used for hydrolysis or for leaching titanyl sulfate, it could not be recovered because it was previously contained in the solution after hydrolysis, causing Ti pollution
It prevents O ₂ loss and is solved by converting the total amount of titanyl sulfate to titanium hydroxide and then calcining it to produce titanium oxide.

That is, one or two selected from the group of oxygen-containing organic extractants, the group of alkylamines and the group of alkylarylamines are added to a sulfuric acid solution obtained by separating titanium hydroxide obtained by hydrolyzing a titanyl sulfate solution. By contacting the organic solvent containing the above, Ti ions in the sulfuric acid solution are extracted as a sulfate complex. Next, water or dilute sulfuric acid is brought into contact with an organic solvent containing Ti and then extracted, whereby titanium in the organic phase is back-extracted into the aqueous solution and the organic solvent is regenerated. The problem is solved by a method for producing titanium oxide, which comprises repeatedly using an aqueous solution containing titanium by back-extraction for the hydrolysis of a titanyl sulfate solution or the leaching of titanyl sulfate.

In addition, the titanyl sulfate solution is hydrolyzed, and the obtained sulfuric acid solution from which the titanium hydroxide is separated is led to a reduced-pressure or normal-pressure evaporation and concentration step.Before obtaining concentrated sulfuric acid, a group of oxygen-containing organic extractants, alkyl Contacting an organic solvent containing one or more selected from the group of amines and alkylarylamines to reduce the amount of titanium sulfate produced in the evaporative concentration step; Is solved.

In the present invention, the back-extraction effect can be enhanced by adding a reducing substance to water or sulfuric acid used to back-extract titanium extracted into the organic phase. Also, by contacting the reducing substance with an organic solvent before back extraction and then contacting water or dilute sulfuric acid to enhance the back extraction effect of titanium in the organic phase, the concentration of titanium in the back extraction solution can be increased. Even if it is used for hydrolysis of titanyl sulfate solution or for leaching of titanium sulfate, sufficient water balance can be obtained, so that the total amount of titanium dissolved in the separated solution after completion of hydrolysis is converted to titanium hydroxide. In this method, the total amount of titanium in the titanyl solution is changed to titanium dioxide.

[Operation] The ferrous titanyl sulfate solution used as a starting material in the present invention is not limited in terms of the use of the present invention regardless of the method used, but generally, ilmenite (ilmenite or anatase) or titanite is used. A concentrated titanium component such as slag is finely pulverized, concentrated sulfuric acid is added thereto, the mixture is stirred, heated and aged, and then leached with water or diluted sulfuric acid in a leaching step. Then added iron scrap to reduce ferric sulfate to ferrous, further solution was cooled, after removal of the ferrous sulfate _{(FeSO 4 · 7H 2 O)} , titanium sulfate excluding solids Iron solutions are often used.

240 to 260 g / as TiO ₂ as an example of a titanium iron solution,
Fe ²⁺ 40-50g / Free sulfuric acid 200-300g / Total sulfuric acid 500-800g /
As metal ions, Mn, V, Mg, Al, Cr and Nb are contained.

From a titanium iron solution that is a titanyl sulfate solution, a method for producing insoluble titanium hydroxide by a hydrolysis method,
There are various methods other than those disclosed in U.S. Pat.No. 2,253,595 and British Patent No. 558,285.In general, it is obtained by leaching the raw material into a low-concentration titanyl sulfate solution kept almost in a boiling state. Titanium iron solution is added with stirring gradually to make a high concentration of iron titanyl sulfate solution once. Then 95
Insoluble titanium hydroxide is obtained by adding about 1/4 volume of 90-95 ° C. water of the iron-titanium solution at 105 ° C. to 105 ° C. At the end of the hydrolysis, the total sulfuric acid concentration in the solution was 320 to 450 g / range, and the Ti ions that could not be hydrolyzed and were present in the aqueous solution were Ti
₇ to 10 g / range as O ₂ , and 94 to 90% of total titanyl sulfate
It means that 95% was converted to titanium hydroxide.

In the present invention, the Ti ion remaining in the hydrolysis-finished solution is brought into contact with an organic solvent containing one or more selected from the group of oxygen-containing organic extractants, the group of alkylamines and the group of alkylarylamines. In particular, the Ti ions in the sulfuric acid solution can be separated from other metals by extracting them as a complex into the organic phase as shown in the following formula.

TiSO ₄ + Org → TiOSO ₄・ Org TiSO ₄ + H ₂ SO ₄ + nOrg → H ₂ TiO (SO ₄ ) ₂・ nOrg + H ₂ O The above equation is only an example of the extraction reaction, and
SO ₄ roasted by the concentration and the anion concentration coexisting metal ions, and also by extraction agent used, Ti is extracted
It is to be understood that the species of

The sulfuric acid complex of titanium extracted into an organic solvent selected from the group of oxygen-containing organic solvents and alkylamines and alkylarylamines is transferred to the aqueous phase as shown in the following formula by contacting with water or dilute sulfuric acid, The organic solvent is regenerated.

TiOSO ₄ · nOrg + water _{→ TiOSO 4 + nOrg ...... TiOSO 4} · nOrg + dilute sulfuric _{→ TiOSO 4 + H 2 SO 4} + nOrg ...... used for back extraction water or dilute hydrazine sulfate, hydrazine sulfate _{Na 2 SO 3, NaHSO 3,} Na By adding ₂ S ₂ O ₄ , (COOH) _2, etc., the effect of back extraction is increased and high concentration of Ti
Can be recovered in concentration.

TiOSO ₄ · Org + N ₂ H ₄ · SO ₄ → 1 / 2Ti ₂ (SO ₄ ) ₃ + 1 / 2H ₂ SO ₄ + H ₂ O + H ⁺ + Org The above formula is only an example of the reverse extraction reaction, and is a reducing substance. Depending on the amount of Ti, not all of the Ti ions are converted to Ti ³⁺ ions, and also depends on the state of contacting the organic phase with the reducing substance before back-extraction, and also on the type of extractant used. Will change.

The acid value of the aqueous solution containing the back-extracted titanium is as low as 2.2 or less, and can be recovered as titanium hydroxide repeatedly in the hydrolysis step.

Alternatively, the aqueous solution containing the back-extracted titanium may be heated to produce titanium hydroxide, separated and then subjected to the hydrolysis step.

Since the aqueous solution containing the back-extracted titanium does not contain other metal ions, an alkali can be added to produce ultrafine titanium hydroxide.

The oxygen-containing organic extractant used in the present invention is selected from the following group.

(A) Group of esters In the formula, R ₁ , R ₂ and R ₃ represent various alkyl groups and aryl groups, and those having 4 to 18 carbon atoms are used. In addition, each alkyl group and aryl group are those having different alkyl groups and aryl groups of R ₁ RR ₂ RR ₃ , R ₁ RR ₂ ≠ R ₃ or R ₁ ≠ R ₂ ≠ R ₃ , or an alkyl group and an aryl group. Are mixed.

(B) Group of alcohols Various (n-, second, and tertiary) alcohols having 6 to 18 carbon atoms.

(C) amide group In the formula, R, R 'and R "represent an alkyl group and an aryl group, and those having 4 to 22 carbon atoms can be used.

R = R '= R ", R = R' ≠ R" or R ≠ R '≠
R ″ or a mixture of an alkyl group and an aryl group can also be used.

The alkylamine and alkylarylamine used in the present invention are used from the following groups.

(A) a primary amine, represented in the form of RNH _2, R is carbon atoms refers to the 4-24 alkyl group or an aryl group.

 An example used in the experiment is shown below.

(B) Secondary amines represented by the form of R ₂ NH, wherein R represents an alkyl group or an aryl group, and those having 4 to 24 carbon atoms are used.

 An example used in the experiment is shown below.

The petroleum hydrocarbon used for diluting the extractant in the present invention is an aromatic hydrocarbon, an aliphatic hydrocarbon, or a mixture thereof.

Miscellaneous hydrocarbon mixtures such as kerosene are also often used.

The reducing substance used in the present invention is selected from the following group,
Only one type may be used, or two or more types may be mixed and used.

H ₂ , CO, CO ₂ , SO ₂ , H ₂ S, Na ₂ S, NaHS, NaC ₂ O ₄ , NH ₄ C ₂ O ₄ , CH ₃ COO
H, CH ₃ COONH ₄ , CH ₃ COONa, NaHSO ₃ , Na ₂ SO ₃ , Na ₂ S ₂ O ₄ , NH ₄ HS
O ₃ , KHSO ₃ , (NH ₄ ) ₂ SO ₃ , Na ₂ S ₂ O ₃ , K ₂ S ₂ O ₃ , (NH ₄ ) ₂ S ₂ O ₃ ,
Metallic iron, metallic zinc, hydrazine hydrate, hydrazine sulfate,
Citric acid, malic acid, gluconic acid and urea (NH ₄ ) ₂ CO ₃ ,
NH ₄ HCO _{3 There are} metallic iron, metallic zinc and mascarobolic acid.

Also the dilute sulfuric acid used for inverse extraction in the present invention refers to the case 250g / H ₂ SO ₄ concentration below that used alone without the addition of a reducing agent. However, when the extraction concentration is 5% or less, up to 300 g / H ₂ SO ₄ can be used for back extraction.

When reducing materials are mixed and used for back extraction, the H ₂ SO ₄ concentration is not limited.

Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings. It should be understood that the present invention is not so limited.

FIG. 1 is a flow sheet showing the basic operation of the present invention. In the hydrolysis step B, a titanyl sulfate solution A containing a large amount of impurity metal ions is kept in a boiling state in water or a dilute titanyl sulfate solution. To reduce the total sulfuric acid concentration of the titanyl sulfate solution, to produce an insoluble titanium hydroxide. In the filtration step C, in addition to titanium hydroxide D and Ti ions, Fe, Mn, Al, Cr, V After separating the sulfuric acid solution containing Mg, Mg, and Nb, the solution is led to an extraction step E, where it is brought into contact with an organic solvent containing an oxygen-containing organic extractant, an alkylamine and an alkylarylamine to thereby form Ti ions in the sulfuric acid solution. To the organic phase as a sulfuric acid complex. The organic solvent that extracts and contains titanium is led to the back-extraction step F, where it is brought into contact with water or dilute sulfuric acid to back-extract Ti into the aqueous solution side, and the organic solvent is regenerated and used repeatedly. Also, a reducing substance is added to water or dilute sulfuric acid to be back-extracted to obtain a back-extraction solution having a high Ti concentration. The liquid after the back extraction is led to the hydrolysis step B, and the titanium is recovered as titanium hydroxide, which is produced as titanium dioxide after firing.

The flow sheet shown in FIG. 2 is basically the same as that shown in FIG. 1, except that the organic solvent containing the extracted Ti is led to the reduction step G before the organic solvent is led to the back extraction step F, and H ₂ gas, SO ₂ gas, etc. After contacting the reducing substance to reduce a part or all of the titanium in the organic phase, the organic solvent is regenerated while the titanium in the organic phase is back-extracted into the aqueous phase by contact with water or dilute sulfuric acid in the back-extraction step F. This is a method for producing titanium oxide which is repeated in the extraction step E again.

The flow sheet of FIG. 3 is basically the same as FIG. 1, but shows that the present invention is also effective for the treatment of a sulfuric acid solution in which titanium is extracted and removed in the extraction step E. . The raffinate is led to an evaporative concentration step H under reduced pressure and normal pressure,
This is a method for producing titanium oxide, which has the advantage of reducing the amount of metal sulfate J that must be discharged when producing high-concentration sulfuric acid that can be used repeatedly.

The flow sheet of FIG. 4 is basically the same as that of FIG. 3, except that the organic solvent containing the Ti is contacted with water or dilute sulfuric acid in the back-extraction step F or a reducing substance is added. In the heating step H ', before the aqueous solution obtained by contacting the back-extraction solution and the organic phase titanium is back-extracted into the aqueous phase in the hydrolysis step B, the titanium contained in the aqueous solution is obtained as titanium hydroxide D'. This is a method for producing titanium oxide in which an aqueous solution ′ is repeated in a hydrolysis step B.

The flow sheet of FIG. 5 is the same as that of FIG. 3, except that concentrated sulfuric acid obtained in the evaporative concentration step H under reduced pressure or normal pressure is repeatedly used in the sulfation step K to form ilmenite (ilmenite or anatase) or titanium concentrated slag M. To make the titanium contained in the raw material into titania sulfate. Next, this is a method for producing titanium oxide in which the process is led to a leaching step L to produce a titanyl sulfate solution A containing impurities by water or a back extraction solution.

The flow sheet of FIG. 6 shows a method of manufacturing titanium oxide by combining FIGS. 2 and 5.

[Example] The present invention will be described below with reference to examples.

Example (1) The composition of the stock solution used in the experiment is shown in Table 1 below.

[Extraction test of TiOSO ₄ ] The organic solvent used in the test was selected from TOPO (tri-octyl phosphine oxide) and THPO (tri-hexal phosphine oxide) from the group of alkyl phosphine oxides, and tested at a concentration of 25% for each. Was done. Table 2 shows the results.

 All extraction conditions were O / A = 1/1 extraction time 5 minutes.

[Back extraction test] The results of the back extraction test of the organic solvents shown in Table 2 are shown in Table 3.

Reverse extraction conditions CO ₂ gas is sealed in a separatory funnel and shaken for a contact time of 10 minutes.

The precipitate formed in the aqueous phase was sufficiently dissolved by adding H ₂ SO ₄ and then Ti was measured. The measurement is based on ICP (ion chromatography emission spectrometer).

No precipitation occurred in either the organic phase or the aqueous phase with the addition of the reducing agent.

Example (2) [Extraction experiment] A continuous extraction experiment was performed using the stock solution shown in Table 1 using an organic solvent obtained by diluting 25% TOPO with an aromatic hydrocarbon.

 Four extraction stages, O / A = 1/1 extraction time 10 minutes.

[Back extraction experiment] A continuous back extraction experiment was performed by selecting NaHSO ₃ as a reducing agent.

The number of back extraction stages is 6, and the back extraction time is 10 minutes.

After reducing the advance Ti by contacting Example (3) Ti organic solvent reducing gas is extracted containing sulfuric acid complex, tested for back-extracted TiOSO ₄ by contact with water or dilute sulfuric acid, Table 6 shows the results.

Example (4) [Production of titanyl sulfate solution] TiO ₂ 44.2%, FeO 34.1%, Fe ₂ O ₃ 12.7%, MnO 0.3
%, Cr ₂ O ₃ 0.01%, V ₂ O ₅ 0.15%, P ₂ O ₅ 0.03%, Al ₂ O ₃
2.7 kg of ilmenite having a chemical composition of 1.2%, CaO 0.25%, MgO 4.72%, SiO ₂ 3.1% is pulverized into a -325 mesh 90
4.5% 95.1% H ₂ SO ₄ was mixed with the% -pass particles and preheated to a temperature of 80 ° C.

Next, a small amount of water is added to accelerate the sulfation reaction. The reaction temperature rises to 210 ° C. After aging for 5 hours in this state, a solution obtained by back-extracting TiOSO ₄ shown in Table 3 (initial 20 g / H
₂ SO ₄ + 5.2g / NaHSO ₃ containing solution with Ti concentration of 3.62g /)
To dissolve the TiOSO ₄ was put into.

Since the reducing agent remains, it was confirmed that the entire amount of Fe ions was present with ferrous sulfate even without introducing Fe scrap.

Insoluble residue 0.31kg Leachate (titanyl sulfate) 5.31 Next, the mixture is cooled to 10 ° C. to separate iron sulfate crystals.

Generated FeSO ₄・ 7H ₂ O 3.6kg A hydrolysis test was performed using the liquid having the above composition.

First, the back extraction liquid 0.5 (60 g / H ₂ SO ₄ +10.4 g)
/ NaHSO ₃ Ti 6.96 g /) is heated to 95 ° C in advance,
The titanyl sulfate solution is continuously added therein.

The back extract 1.1 is heated to 95 ° C. in a liquid adjusted to a certain concentration and maintained at a liquid temperature of 95 to 98 ° C., and then added.

The liquid temperature is raised to the boiling point, and when precipitation is confirmed, heating and stirring are stopped to ripen.

When about 30 minutes had elapsed, stirring was started and the liquid temperature was again raised to the boiling point. In this state, 3 hours were allowed to elapse, and then 60 g / H ₂ SO ₄ +10.4 g / NaHSO ₃ Ti obtained in Table 3 were obtained. 6.96g /
1.51 was added, and the end of the hydrolysis was confirmed by analysis, and then stopped.

Dehydrate, wash and pickle the resulting insoluble titanium hydroxide,
Further, the mixture was mixed with 0.5% (wt) K ₂ SO _4, 0.1% (wt) Al ₂ (SO ₄ ) ₃ and 0.1% (wt) ZnSO ₄ and then fired at 870 ° C. for 60 minutes.

The obtained TiO _{2 was} 1.06 kg. The collection rate from the dissolved titanyl sulfate solution was 100.9%, and the entire amount of TiO ₂ supplied from the back extract was recovered.

The value of 9.1 g / TiO ₂ is normal as remaining in the sulfuric acid solution after hydrolysis, and confirms that the total amount of TiO ₂ in the back extract used for hydrolysis has become a product. .

The yield of titanium oxide as a product from titanyl sulfate solution was 100.9% compared to 94-95% of the conventional method, indicating a clear recovery effect.

[Brief description of the drawings]

FIG. 1 is a flow sheet showing a basic type of operation of the present invention,
FIG. 2 shows a process in which titanium is extracted into the organic phase and a reducing substance is brought into contact with the titanium before the back-extraction step to enhance the back-extraction effect of titanium. FIG. 3 is completely different from FIG. FIG. 3 is the same, but showing that the present invention affects the concentration and recovery of the sulfuric acid solution after extraction and removal of Ti. FIG. 4 is the same as FIG. 1, but illustrates a method for recovering titanium hydroxide by heating and hydrolyzing a liquid in which titanium which is repeatedly returned to the hydrolysis step is recovered. FIG. 5 is basically the same as FIG. 3 except that the solution from which titanium has been removed is concentrated and the concentrated sulfuric acid is used. FIG. 6 is a diagram in which the processing methods of FIGS. 2 and 5 are combined. A: A starting material of the present invention in the form of a titanyl sulfate solution containing no impurities or containing a titanyl sulfate B: By mixing with a solution of titanyl sulfate in a heated state of water or dilute sulfuric acid at 90 to 105 ° C and stirring. Hydrolysis Step for Producing Insoluble Titanium Hydroxide This is a step of filtering and separating titanium hydroxide obtained by hydrolysis. D: Titanium oxide is formed by firing with filtered and dehydrated titanium hydroxide. E: Ti present in the sulfuric acid solution filtered off after hydrolysis
Step of extracting and removing ions as a sulfate complex F: Step of extracting titanium by contacting water or diluted sulfuric acid or a liquid obtained by adding water or diluted sulfuric acid with a reducing substance to an organic solvent containing titanium and back-extracting titanium into an aqueous phase G: Step of reducing titanium in the organic phase H: Step of evaporating and concentrating sulfuric acid from which titanium has been extracted and removed under reduced pressure or normal pressure J: Metal sulfate produced from the evaporative concentration step K: Titanium ore or titanium slag L: Leaching step M: Titanium raw material such as ilmenite or titanium-concentrated slag etc .... 1 selected from the group consisting of oxygen-containing organic solvents, alkylamines and alkylaryls Organic solvent containing one or more species …… Aqueous solution for back-extraction of sulfate complex of titanium… Reducing substance …… Complete solution for back-extraction of titanium… Concentrated sulfuric acid

Claims (7)

(57) [Claims] 1. The method of claim 1, wherein the titanyl sulfate solution is hydrolyzed, and the obtained titanium hydroxide is separated into a sulfuric acid solution, which is selected from a group of oxygen-containing organic extractants, a group of alkylamines, and a group of alkylarylamines. By contacting an organic solvent containing one or more kinds, a Ti ion in the sulfuric acid solution is extracted as a sulfate complex, and then water or diluted sulfuric acid is brought into contact with the organic solvent containing the extracted Ti. The feature is that titanium in the organic phase is back-extracted into the aqueous solution and the organic solvent is regenerated, and the aqueous solution containing the back-extracted titanium is used repeatedly for hydrolysis of the titanyl sulfate solution or for leaching of the titanyl sulfate. A method for producing titanium oxide. 2. An oxygen-containing organic extractant is obtained by hydrolyzing a titanyl sulfate solution and subjecting the obtained sulfuric acid solution from which titanium hydroxide has been separated to an evaporation / concentration step under reduced pressure or normal pressure to obtain concentrated sulfuric acid. Contact with an organic solvent containing one or more selected from the group consisting of, alkylamines and alkylarylamines to reduce the amount of titanium sulfate produced in the evaporative concentration step. The method for producing titanium oxide according to claim 1, wherein: 3. An organic solvent containing a sulfate complex of titanium in contact with a reducing substance, and then contacting water or dilute sulfuric acid to back-extract titanium in an organic phase into an aqueous solution and regenerate the organic solvent. The method for producing titanium oxide according to claim 1, wherein: 4. The method for producing titanium oxide according to claim 1, wherein a reducing substance is added to water or diluted sulfuric acid used for back-extraction of titanium extracted in the organic solvent. 5. A method in which a solution obtained by back-extracting titanium is led to a step of evaporating and concentrating under reduced pressure or normal pressure to obtain a solution obtained by hydrolyzing titanium in an aqueous solution, and the separated aqueous solution is repeatedly used for hydrolyzing a titanyl sulfate solution. The method for producing titanium oxide according to claim 1. 6. The method for producing titanium oxide according to claim 1, wherein an alkali is added to the solution from which titanium has been back-extracted and the titanium is recovered by hydrolysis. Method. 7. The method according to claim 1, wherein when the Ti ions extracted and contained in the organic solvent are back-extracted by using water or dilute sulfuric acid, the extraction is performed in a step of electrochemically forming a reduced region. Item 4. The method for producing titanium oxide according to Item 1.