KR102505186B1 - Method for recovering titanium(Ti) selectively from hydrometallurgical extraction process - Google Patents

Abstract

The present invention comprises the steps of obtaining a raw material by removing iron (Fe) from a mineral containing iron (Fe), silicon (Si), niobium (Nb) and titanium (Ti); removing impurities by first removing silicon (Si) from the raw material and performing solid-liquid separation to obtain a residue containing Na ₂ TiO ₃ ; A leaching step of obtaining a leaching solution containing titanium (Ti) by adding a leaching solution to the residue; an extraction step of obtaining valuable metals in the organic phase from which iron (Fe) and zinc (Zr) are removed by adding an acid extractant and a diluent to the leaching solution; A method for selectively recovering titanium (Ti) through hydrometallurgy including a recovery step of obtaining titanium (Ti) from which silicon (Si), niobium (Nb), and sodium (Na) are removed by adding a stripping solution to the valuable metal. It is about.

Description

Method for recovering titanium (Ti) selectively from hydrometallurgical extraction process}

The present invention relates to a selective recovery method of titanium (Ti) through hydrometallurgy.

The titanium (Ti) smelting industry can be largely divided into metal titanium (Ti) production and synthetic rutile titanium dioxide (TiO ₂ ) production. Titanium (Ti) alloys are widely used in the aerospace, automobile, and biopharmaceutical industries due to their high strength, low density, high temperature resistance, corrosion resistance, and excellent biocompatibility.

Titanium dioxide (TiO ₂ ), another industrial source of titanium (Ti), is applied to the pigment, rubber, filter paper, catalyst, and plastic industries. The main ores of titanium (Ti) are natural rutile (TiO ₂ ) and ilmenite (FeTiO ₃ ), which contain 90% titanium (Ti) and 30% to 65% Ti, respectively.

Rutile has the highest content of titanium (Ti) among titanium (Ti) ores, but its conservation area and reserves are limited. On the other hand, 94% of ilmenite is found worldwide. Therefore, since the use of ilmenite ore is easy, ilmenite is used more as a raw material for smelting titanium (Ti) than rutile.

Commercial titanium (Ti) smelting processes from Ilmenite are known, such as the slag process, the UGS process, the Becher process, and the Benelite process, and these processes can concentrate TiO ₂ to 86%, 95%, 90%, and 95%, respectively. .

Concentrated TiO ₂ is produced from sponge metal titanium (Ti) or TiO ₂ (synthetic rutile) by the Kroll process or the chlorination method. That is, the main commercial processes for refining Ti are mainly pyrolysis processes. On the other hand, in the case of the hydrometallurgical process, although the sulfuric acid method is widely known, only titanium dioxide (TiO ₂ ) can be produced and the purity of the product is low.

Because of the above problems, the commercial hydrometallurgical process is mainly used as a process to remove impurities from ilmenite minerals. In order to solve the problems of the sulfuric acid method and the direct leaching method during the hydrometallurgical process of titanium (Ti), many studies on producing titanium dioxide (TiO ₂ ) through a wet separation and refining process have been reported.

However, in the leaching process, the leaching rate of titanium (Ti) was low, so the separation and purification process of titanium (Ti) from a solution containing low concentration titanium (Ti) was studied. In the stripping process, a problem in which the recovery rate of titanium (Ti) is low occurs.

Korean Patent Registration No. 10-1790128 (registered on October 19, 2017)

The present invention has been made to solve the above problems, to provide a selective recovery method of titanium (Ti) through hydrometallurgy, specifically, from a leaching solution containing high concentration of titanium (Ti) to the hydrometallurgical process It is an object of the present invention to provide a method for producing high purity titanium dioxide (TiO ₂ ).

The above object is to obtain a raw material by removing iron (Fe) from a mineral containing iron (Fe), silicon (Si), niobium (Nb) and titanium (Ti); removing impurities by first removing silicon (Si) from the raw material and performing solid-liquid separation to obtain a residue containing Na ₂ TiO ₃ ; A leaching step of obtaining a leaching solution containing titanium (Ti) by adding a leaching solution to the residue; an extraction step of obtaining valuable metals in the organic phase from which iron (Fe) and zinc (Zr) are removed by adding an acid extractant and a diluent to the leaching solution; and a recovery step of adding a stripping solution to the valuable metal to obtain titanium (Ti) from which silicon (Si), niobium (Nb), and sodium (Na) are removed. achieved by the method

In the step of removing impurities, at least one salt selected from sodium hydroxide (NaOH), sodium carbonate (Na ₂ CO _{3 )} , sodium nitrate (NaNO _{3 )} and sodium sulfate (Na ₂ SO _{4 )} is added to the raw material to form a soluble compound. changing soda roasting step; and a water leaching step of removing impurities by adding distilled water after the soda roasting, wherein the soda roasting step and the water leaching step may be repeated at least twice.

In the impurity removal step, the residue may further contain silicon dioxide (SiO ₂ ), niobium pentoxide (Nb ₂ O ₅ ), zirconium dioxide (ZrO ₂ ) and iron oxide (Fe ₂ O ₃ ). can

In the extraction step, the acid extractant is composed of bis-(2-ethylhexyl) phosphoric acid (D2EHPA), 2-ethylhexyl phosphonic acid mono-2-ethylhexyl phosphoric ester, Tri-alkyl phosphine oxide and Tri-octyl phosphine oxide group, and the diluent may be characterized in that it includes xylene and kerosene.

The concentration of titanium (Ti) in the organic phase in the extraction step can be obtained through the following concentration formula,

[formula]

(Titanium (Ti) initial concentration x extraction rate) ÷ O/A ratio

(The O/A ratio represents the ratio of the organic phase to the aqueous phase.)

It may be characterized in that the number of stages for extracting the titanium (Ti) from the valuable metal in the organic phase is changed according to the O/A ratio in the above formula.

The stripping solution in the recovery step may be characterized in that it is selected from the group consisting of distilled water, hydrochloric acid (HCl) and sodium chloride (NaCl).

In the recovery step, the titanium (Ti) stripping is performed through a countercurrent multi-stage stripping process by stripping solution treatment, and the titanium (Ti) stripping rate obtained through the stripping process can be obtained through the following formula can do.

[formula]

(Concentration of valuable metals removed ÷ O/A ratio) ÷ Concentration of valuable metal titanium (Ti) in the organic phase

(The O/A ratio represents the ratio of the organic phase to the aqueous phase.)

A drying step of drying titanium (Ti) precipitated through the countercurrent multi-stage stripping process to form a precipitate: a washing step of treating the precipitate with a washing solution having a pH of 2 to 5, wherein the washing solution includes distilled water, and the washing Remove the chloride ion (Cl ^- ) in the precipitate through; And it may be characterized in that it further comprises a calcination step of calcining at 600 ~ 700 ℃ after the washing step.

According to the present invention, a method for selectively recovering titanium (Ti) through hydrometallurgy is provided, and specifically, a method for producing high purity titanium dioxide (TiO ₂ ) from a leaching solution containing a high concentration of titanium (Ti) by a hydrometallurgical process is provided.

1 is a process chart for a selective recovery method of titanium (Ti) through hydrometallurgy according to an embodiment of the present invention,
Figure 2 is a result showing the McCabe-Thiele diagram according to the O / A ratio in the selective recovery method of titanium (Ti) through hydrometallurgy according to an embodiment of the present invention,
Figure 3 shows the removal behavior of titanium (Ti) in the experimental example of the present invention,
Figure 4 shows the recovery efficiency of titanium (Ti) according to the hydrolysis (hydrolysis) experiment in the experimental example of the present invention,
Figure 5 shows the color change of titanium dioxide (TiO ₂ ) recovered in the experimental example of the present invention,
6 is an XRD analysis result of titanium dioxide (TiO ₂ ) prepared in an experimental example of the present invention,
7 is a SEM analysis result of titanium dioxide (TiO ₂ ) prepared in an experimental example of the present invention.

The present invention will be described in more detail with reference to the following drawings.

Since the accompanying drawings are only examples shown to explain the technical spirit of the present invention in more detail, the spirit of the present invention is not limited to the accompanying drawings. In addition, in the accompanying drawings, sizes and intervals may be exaggerated unlike actual ones in order to explain the relationship between each component.

Referring to FIG. 1, a method for selectively recovering valuable metals through hydrometallurgy according to the present invention will be described.

1 is a process chart for a method for selectively recovering valuable metals through hydrometallurgy according to an embodiment of the present invention.

First, a raw material is obtained by removing iron (Fe) from a mineral containing iron (Fe), silicon (Si), niobium (Nb), and titanium (Ti). (S1)

In this step, iron (Fe) is removed through the chlorination method, and in the raw material from which iron (Fe) is removed, FeO, SiO ₂ , Nb ₂ O ₅ , Al ₂ O ₃ , ZrO ₄ , V ₂ O ₅ , Impurities such as MgO, MnO and CaO may be further included.

In this embodiment, it is shown that iron (Fe) is first removed from impurities and then the remaining impurities (Si, Nb, etc.) are removed to obtain final titanium dioxide (TiO ₂ ), but this process may vary depending on the type of mineral, Depending on the composition of the valuable metal contained in the mineral, the process of treating impurities may also vary.

Next, an impurity removal step is performed in which silicon (Si) in the raw material is first removed, and a residue containing Na ₂ TiO ₃ is obtained by solid-liquid separation. (S2)

Although not limited thereto, at least one salt (Na series salt) selected from sodium hydroxide (NaOH), sodium carbonate (Na ₂ CO ₃ ), sodium nitrate (NaNO ₃ ) and sodium sulfate (Na ₂ SO ₄ ) to remove impurities. Soda roasting, which is phase-changed into a soluble compound by adding

During soda roasting, the mixing ratio of minerals and Na-based salts may be carried out under conditions of 0.5-3% by weight and 300-700 ° C.

Through the soda roasting process through Na-based salts as above, insoluble titanium dioxide (TiO ₂ ) is phase-changed into leachable Na ₂ TiO ₃ into a soluble compound. Raw material that was not leached is changed to leachable form. In addition, in the impurity removal step, after soda roasting, distilled water is added to perform water leaching to remove impurities, and a large amount of impurities can be removed through the water leaching.

In this step, soda roasting and water leaching are repeated at least twice, and through these repetitions, the content of silicon (Si) in the raw material is greatly reduced, and vanadium (V) and aluminum (Al), which were found in small amounts in the raw material, ) can also be removed.

After the soda roasting and water leaching steps, a residue containing Na ₂ TiO ₃ can be obtained through solid-liquid separation, and the residue contains silicon dioxide (SiO ₂ ), niobium pentoxide (Nb ₂ O ₅ ), zirconium dioxide ( ZrO ₂ ) and iron oxide (Fe ₂ O ₃ ) may be further contained.

Next, a leaching step is performed to obtain a leaching solution containing titanium (Ti) by adding a leaching solution to the residue. (S3)

The leaching solution in the leaching step includes hydrochloric acid (HCl), and the leaching solution may further contain silicon (Si), niobium (Nb), sodium (Na), zinc (Zr), and iron (Fe).

In this step, 1M-7M hydrochloric acid (HCl) may be used, and it may be performed under conditions between room temperature and 90 ° C. At this time, the concentration of titanium (Ti) in the leaching solution is 10 g / L to 35 g / L may contain

Optimal titanium (Ti) leaching conditions according to the temperature in this step will be described through specific examples below.

Next, an extraction step of obtaining valuable metals in the organic phase from which iron (Fe) and zinc (Zr) are removed by adding an acid extractant and a diluent to the leaching solution is performed. (S4)

The acid extracting agent may be selected from the group consisting of bis-(2-ethylhexyl) phosphoric acid (D2EHPA), 2-ethylhexyl phosphonic acid mono-2-ethylhexyl phosphoric ester, tri-alkyl phosphine oxide and tri-octyl phosphine oxide, As the diluent, xylene and kerosene may be used.

The diluent addition in this step is performed for a smooth solvent extraction process because the viscosity of the leaching solution obtained through the previous leaching step (S3) is quite high. explain through

At this stage, the concentration of titanium (Ti) in the organic phase can be obtained through the following concentration formula,

[formula]

(Titanium (Ti) initial concentration x extraction rate) ÷ O/A ratio

The O/A ratio represents the ratio of the organic phase and the aqueous phase, and the ratio is 10, 8, 6, 4, 2, 1, 0.5 and 0.25, and is performed under the conditions of 1, 0.5 and 0.25. The number of stages for extracting titanium (Ti) may be changed. That is, the extraction rate of valuable metals varies according to the counterflow multi-stage extraction process according to the conditions of each O/A, which affects the removal of impurities in the leaching solution.

Next, a recovery step of obtaining titanium (Ti) from which silicon (Si), niobium (Nb), and sodium (Na) are removed by adding a stripping solution to the valuable metal is performed. (S5)

The stripping solution in this step may be selected from the group consisting of distilled water, hydrochloric acid (HCl), and sodium chloride (NaCl), and the amount of valuable metals removed varies depending on the stripping solution and the number of times the stripping solution is treated.

Specifically, titanium (Ti) stripping is performed through a countercurrent multi-stage stripping process by stripping solution treatment, and the titanium (Ti) stripping rate obtained through the stripping process can be obtained through the following formula.

[formula]

(Concentration of valuable metals removed ÷ O/A ratio) ÷ Concentration of valuable metal titanium (Ti) in the organic phase

The O/A ratio represents the ratio of the organic phase to the aqueous phase, and the ratio is carried out under conditions of 10, 8, 6, 4, 2, 1, 0.5 and 0.25.

Next, a drying step of forming a precipitate by drying the titanium (Ti) precipitated through the countercurrent multi-stage stripping process is performed. (S6)

The stripping solution recovered in this step is subjected to hydrolysis under conditions of 20 to 24 hours, 80 to 120 RPM and 80 to 100 ° C, and titanium dioxide (TiO ₂ ) precipitated through hydrolysis is stored in a dryer at about 60 to 70 ° C. It can be obtained by drying under

Next, a washing step of treating the precipitate with a washing solution of pH 2-5 and a calcination step of calcining it under specific temperature conditions are performed. (S7)

The washing liquid used in this step includes distilled water, and chloride ions (Cl ^- ) in the precipitate are removed through washing. The washing step as described above is performed by repeated washing step by step, and the color of titanium dioxide (TiO ₂ ) is changed to white through repeated washing.

After the washing step, a calcination step of calcining under 600 to 700 ° C conditions is performed for 20 to 24 hours, and high-quality titanium dioxide (TiO ₂ ) is produced as a final product.

Hereinafter, the present invention will be described in more detail through experimental examples. The following experimental examples are only for explaining the present invention in more detail, and it is to those skilled in the art that the scope of the present invention is not limited by these comparative examples and examples according to the gist of the present invention. It will be self-explanatory.

[Experiment 1: Acquisition of raw material from which iron (Fe) is removed by chlorination method]

Experimental Example The raw material used was a domestic high-quality Pyeongtaek sander with a high content of titanium dioxide (TiO ₂ ), and a raw material containing more than 87% of titanium dioxide (TiO ₂ ) was used through the selective chlorination process.

The composition of the raw material from which a large amount of iron (Fe) was removed by the chlorination method is shown in Table 1 below. As can be seen from Table 1, it can be seen that even though iron (Fe) is removed, about 5-6% of iron (Fe) is contained.

In the case of the remaining impurities, it can be seen that silicon (Si) and niobium (Nb) are contained as impurities, although at low concentrations.

In the case of silicon (Si) and niobium (Nb), when recovering titanium (Ti), it is quite difficult to purify by wet and dry smelting methods, so silicon (Si) and niobium (Nb) ) was tried to control, and at the same time, insoluble titanium dioxide (TiO ₂ ) was phase-changed into Na ₂ TiO ₃ to be changed into a soluble compound.

[ to the chloride method raw material from which iron (Fe) has been removed by Furtherance] unit:[%] Element TiO ₂ FeO SiO ₂ Nb ₂ O ₅ Al ₂ O ₃ ZrO ₂ V ₂ O ₅ MgO MnO CaO High grade TiO ₂ 87.1 5.97 4.28 0.50 0.82 0.35 0.02 0.34 0.39 0.18

In order to check whether leaching is possible due to phase change, the results are shown in Table 2 below when insoluble titanium (Ti)-containing raw materials are leached with hydrochloric acid.

[Composition in leach solution after hydrochloric acid leaching] Unit: [mg/L] Element Ti Si Nb Na Zr Fe hydrochloric acid leach solution 8 - - - - 676

As can be seen in Table 2, only 8 mg/L of titanium (Ti) was leached, and only 676 mg/L of iron (Fe) was leached, and the remaining impurities were not analyzed. Therefore, in the present invention, soda roasting was performed to change the phase to soluble Na ₂ TiO ₃ , and subsequent water leaching was performed.

[Experiment 2: Na through impurity removal step ₂ TiO ₃ Acquisition of residues containing

The raw material from which iron (Fe) was removed by the chlorination method in Table 1 was roasted in N-order soda at 300-700 ° C, followed by water leaching, and the results are shown in Table 3 below.

About 0.96% (water leaching removal amount: 2.2g/L) of silicon (Si) was removed in the first round, 0.4% (water leaching removal amount: 1.59g/L) was removed in the second round, and 0.32% in the third round (water leaching removal amount: 1.2 g/L), and 0.18% (water leaching removal amount: 0.54 g/L) was removed in the fourth round. This shows a Si removal rate of about 40-50% for each cycle.

Finally, the content of silicon (Si) in the raw material decreased from about 2% to 0.18%. In other words, through water leaching after nth soda roasting, the content of silicon (Si) in the raw material could be reduced to about 0.18% or less, and small amounts of impurities such as vanadium (V) and aluminum (Al) could also be removed. could

[ Nth Silicon in the raw material after soda roasting and water leaching ( Si ) content] unit:[%] Soda roasting and water leaching times Si content after soda roasting Si content in water leaching Si content in raw material 2.0 - 2 One 1.6 0.58 1.04 2 1.1 0.42 0.64 3 0.6 0.32 0.32 4 0.3 0.14 0.18

[Experiment 3: Obtaining leaching solution containing titanium (Ti) through leaching step]

The composition of the residue obtained after chlorination and water leaching according to [Experiment 2] is shown in Table 4 below, and a leaching step using hydrochloric acid was performed. The leaching reaction equation is shown in Equation (1) below.

Equation (1): Na ₂ TiO ₃ + 4HCl → TiOCl ₂ + 2NaCl +2H ₂ O

[leaching target residue my Furtherance] unit:[%] Element Ti Si Nb Ca V Na Al Zr Fe Mg Mn % 31.8 0.18 0.09 - - 9.5 - 0.15 2.3 0.18 0.02

The residue in Table 4 was leached by temperature using 5M hydrochloric acid. The results are shown in Table 5 below. As can be seen in Table 5, as the temperature increases, the leaching rate of titanium (Ti) increases, but at a temperature of 80 ° C. or higher, the leaching rate of titanium (Ti) tends to decrease over time.

[Titanium by temperature ( Ti )of leaching rate] (250 RPM, high-liquid ratio 1:10, 5M HCl), unit: [%] hour 30℃ 50℃ 60℃ 70℃ 80℃ 90℃ 100℃ 5 17.5 20.6 21.2 25.0 35.2 39.1 36.7 10 23.5 26.7 27.3 37.0 49.1 51.8 53.7 15 25.9 33.1 33.9 43.9 53.9 57.3 60.1 30 27.3 39.1 41.2 53.3 67.6 65.5 23.0 45 28.8 43.6 47.3 60.9 74.8 60.0 10.4 60 30.2 49.1 55.2 67.3 77.0 50.0 3.1 90 32.3 56.7 61.2 75.5 70.3 24.3 1.4 120 34.2 61.8 71.5 84.2 56.7 14.1 1.0 180 39.5 70.5 81.2 93.0 32.1 5.7 0.9 240 42.7 77.8 87.6 96.1 15.3 2.7 0.3

This is because the leached titanium (Ti) is hydrolyzed and reduced as time elapses and temperature increases. Therefore, it can be seen that the leaching rate of titanium (Ti) reached only 0.3% after 240 minutes at 100 ° C.

Therefore, the condition of 5M HCl and 70 ℃ in which titanium (Ti) was leached by 96.1% or more was selected as the optimal leaching condition.

[Experiment 4: Valuable metal acquisition through extraction step]

The leaching solution obtained in the leaching step (5M HCl, 70 ℃) of [Experiment 3] was used as a solvent extraction feed solution, and its composition is shown in Table 6 below.

[Composition of Valuable Metals in Solvent Extraction Feed Solution] Unit: [mg/L] Element Ti Si Nb Na Zr Fe Leaching solution after nth soda roasting 32050 110 88 9540 130 2614

Table 7 below shows the extraction rate of valuable metals according to tri-alkyl phosphine oxide concentration and diluent.

[ Tri -alkyl phosphine Valuable metal by oxide extraction rate] (O/A=1, 25℃ conditions), unit: [%] extraction system solvent concentration Fe Ti Zr Si Nb Tri-alkyl phosphine oxide, in kerosene 0.1 100.0 3.1 98.5 0.1 0.0 0.3 100.0 16.1 99.6 1.0 0.0 0.5 100.0 27.6 99.6 2.1 0.1 0.7 100.0 38.5 99.6 1.7 0.0 Tri-alkyl phosphine oxide, in xylene 0.1 100.0 0.0 47.7 2.3 0.00 0.3 100.0 6.9 100.0 0.2 0.00 0.5 100.0 15.9 100.0 0.00 0.00 0.7 100.0 22.5 100.0 0.00 0.00 One 100.0 34.5 100.0 0.00 0.35

As can be seen in Table 7, it can be seen that almost all of iron (Fe) and zinc (Zr) are extracted regardless of the extraction system.

In the case of titanium (Ti), it can be confirmed that the extraction rate of titanium (Ti) is higher when kerosene is used as a diluent depending on the concentration of tri-alkyl phosphine oxide than when xylene is used as a diluent. there is. However, it was not significantly related to the extraction rate of titanium (Ti).

Table 8 below shows the amount of stripping by 1M hydrochloric acid (HCl) from the loaded organic obtained from the extraction according to Table 7.

[ Tri -alkyl phosphine in oxide 1M by HCl Ti's stripping amount] Unit: [mg/L] Tri-alkyl phosphine oxide, M 0.1 0.3 0.5 0.7 One Kerosene 440 1540 1900 2200 - Xylene - 3060 4950 5490 6870

As can be seen in Table 8, in the case of titanium (Ti) extracted by tri-alkyl phosphine oxide using xylene as a diluent, the amount of removal of titanium (Ti) is significantly higher than that of using kerosene as a diluent. can know In particular, the removal amount was more than twice as high for each tri-alkyl phosphine oxide solvent concentration.

Therefore, since there is no significant difference in the extraction rate of titanium (Ti) according to the diluent, it is more advantageous to use xylene as a diluent in the stripping process to recover titanium (Ti) in an aqueous solution.

O/A isotherm experiments were performed using 1M tri-alkyl phosphine oxide diluted in xylene under conditions of O/A = 10, 8, 6, 4, 2, 1, 0.5, and 0.25. Through this experiment, the McCabe-Thiele diagram was drawn to determine the theoretical number of extraction stages of titanium (Ti).

Figure 2 is a result showing the McCabe-Thiele diagram according to the O / A ratio in the selective recovery method of titanium (Ti) through hydrometallurgy according to an embodiment of the present invention.

Through Figure 2, the operating line requires about 4 stages when Ti is extracted using 1M Tri-alkyl phosphine oxide diluted in xylene under O/A=3 conditions, and O/A= 5 to reduce the number of extraction stages. When the experiment is performed under the conditions of, it can be seen that about two stages are required.

Table 9 below shows simulation results based on the experimental results of FIG. 2 .

[O/ A star conditional Countercurrent Valuable metals in simulated multi-stage extraction process extraction rate ] Unit: [mg/L] O/A Element Ti Si Nb Fe Zr 3 1 stage 16.7 0.9 4.5 99.8 98.5 2 stages 65.1 5.5 6.8 0 0 3 stages 96.4 7.3 8.0 0 0 4 stages 99.6 8.2 9.1 0 0 5 1 stage 80.5 2.7 8.0 99.6 96.2 2 stages 98.7 7.3 18.2 0 0

As shown in Table 9, when the countercurrent 4-stage extraction experiment was performed under the condition of O / A = 3, 31.92 g / L, 99.6% of titanium (Ti) was extracted based on the aqueous solution. Since the experiment was conducted under the condition of O/A=3, applying O/A=3 corresponds to the extraction of 10640 mg/L Ti as the loaded organic.

In the case of the remaining impurities, about 8.2% of silicon (Si) was extracted as 3mg/L, which was extracted as an organic phase (loaded organic), niobium (Nb) was 9.1%, 2.7mg/L, and iron (Fe) was 99.8%, 870 mg/L. L was extracted, and zinc (Zr) was extracted at 42.7mg/L, which is 98.5%.

On the other hand, when the countercurrent two-stage extraction experiment was performed under the condition of O / A = 2, titanium (Ti) was extracted at 31.6 g / L, which is 98.7% based on the aqueous solution. Applying A=2, 15815 mg/L was extracted.

For the remaining impurities, when O/A=2 was applied, silicon (Si) was extracted at about 7.3%, 4 mg/L, niobium (Nb) was 18.2%, 8mg/L, and iron (Fe) was 99.6%, 1301. mg/L was extracted, and 62.5 mg/L, 96.2% of zinc (Zr), was extracted as the loaded organic.

That is, it can be seen that as the number of stages increases, the extraction rate of titanium (Ti) slightly increases, and the extraction rate of silicon (Si) and niobium (Nb), which are impurities, decreases. The formula for the concentration of valuable metals in the organic phase after extraction is shown in Equation (2).

Equation (2): Valuable metal concentration in the organic phase after extraction Formula: [(Ti initial concentration x extraction rate) ÷ O/A ratio]

Table 10 below shows an experiment for selecting the optimal stripping solution at O/A=2 using distilled water, 0.1M, 0.5M, 1M HCl, 0.1M, 0.5M, 1M NaCl, etc. from the loaded organic phase obtained. will be.

[1M Tri -alkyl phosphine from the loaded organic phase after extraction with oxide. stripping solution Valuable metals by star and number of times removal amount ] Unit: [mg/L] Ti Si Nb Zr Fe 1 distilled water 12460 1.189 3.9 0 2.77 2 times distilled water 5100 0.19 2.6 0 240 0.1M HCl 1 time 12190 1.26 3.9 0 2.09 0.1 M HCl 2 times 5190 0.19 2.9 0 108 0.5M HCl 1 time 11230 1.25 3.8 0 1.9 0.5M HCl twice 5015 0.3 0 0 7.94 1 M HCl 1 time 10320 0.9 3.8 0 0 1 M HCl 2 times 5000 0.1 5.9 0 0 0.1 M NaCl 1 time 8411 0.8 3.8 0 2.5 0.5 M NaCl 1 time 6506 0.8 3.4 0 2.5 1 M NaCl 1 time 4511 1.1 3.4 0 2.4 1 M NaCl twice 4667 0.4 2.1 0 2.6 undiluted 10640 6 2.7 42 871

Looking at the removal rate of titanium (Ti) shown in Table 10, the highest removal amount of 12460 mg / L was removed when distilled water was used, which corresponds to a removal rate of about 58.65%.

During the second stripping ^of distilled water, the amount of titanium (Ti) removed was about half of the first stripping amount, and 5100 mg/L was removed.

When stripping using hydrochloric acid, it can be seen that as the concentration of hydrochloric acid increases, the amount of titanium (Ti) removed slightly decreases. That is, as the concentration of Cl in the stripping solution increased, the removal rate of Ti decreased, but in all cases, more than 10 g/L of titanium (Ti) was removed.

When stripping was performed using sodium chloride (NaCl), which is not affected by acid at all and has only the effect of Cl ^- , it can be seen that the removal rate of titanium (Ti) decreases as the concentration of Cl ^- increases.

Based on this result, it can be determined that the concentration of Cl ^- and H ⁺ ion have the most influence on the removal rate of tri-alkyl phosphine oxide.

Looking at Table 10, it can be seen that the highest removal rate of titanium (Ti) requires distilled water to be selected as the stripping solution, but 240 mg / L of iron (Fe) is removed from the second stripping. And, iron (Fe) was removed under all other conditions, which would obviously reduce the purity of TiO ₂ by acting as an impurity in the hydrolysis process.

However, when only 1M hydrochloric acid (HCl) was used, iron (Fe) was not removed at all times of stripping, once and twice. Therefore, considering the selective stripping process of titanium (Ti), 1M hydrochloric acid (HCl) was selected as the optimal stripping solution.

Figure 3 below shows the stripping behavior of titanium (Ti) in the experimental example, using 1M hydrochloric acid (HCl), continuously anti-current 4-stage stripping experiment and cross stripping experiment at O / A = 2 O / A = It was performed under the conditions of 1.

As can be seen in FIG. 3, 13040 mg/L titanium (Ti) could be concentrated and stripped in the countercurrent multi-stage stripping process, which corresponds to a stripping rate of 61.2%.

Theoretically, titanium (Ti) remains at about 4120 mg/L in the loaded organic. In order to remove 4120 mg/L titanium (Ti) remaining in the loaded organic phase, cross stripping experiments were conducted twice in succession to remove 2690 mg/L and 490 mg/L Ti, respectively, at O/A=1. As a result, only 940 mg/L of titanium (Ti) was left in the loaded organic phase.

This is a value corresponding to the removal of 91.1% titanium (Ti) through the 4-stage countercurrent stripping and continuous cross stripping process. And as impurities in the stripping solution, only 1.2 mg/L and 1 mg/L of silicon (Si) and niobium (Nb) were contained in the stripping solution, and iron (Fe) and zinc (Zr) were not stripped at all. It didn't work. The titanium (Ti) removal rate formula from the loaded organic phase after extraction is shown in Equation (3) below.

Equation (3): Ti stripping rate Formula: [(Concentration of valuable metal stripped ÷ O/A ratio) ÷ Concentration of Ti valuable metal in organic phase]

[Experiment 5: Titanium (Ti) acquisition through recovery step]

Figure 4 shows the results of a hydrolysis experiment conducted under 100 RPM, 90 ℃ conditions for 24 hours for the stripping solution recovered through the extraction step of [Experiment 4], and Figure 5 shows the result through the recovery step It shows before and after washing the obtained titanium dioxide (TiO ₂ ).

As can be seen in FIG. 4, the precipitation rate of titanium (Ti) increased over time, and at about 720 minutes, more than 99% of Ti was recovered in the form of a precipitate.

The precipitated residue was dried in a dryer at about 70° C., and the color after drying was light ivory. Since impurities in the stripping solution were detected in very small amounts, the reason why the dried precipitate did not show a white color was determined to be due to Cl-. Therefore, it was washed with distilled water about 4 times to remove Cl-.

The pH of the washing solution increased to 2.53 for the first wash, 3.13 for the second wash, 4.44 for the third wash, and 4.98 for the fourth wash, and the color of the precipitate also changed to white. You can check.

6 and 7 show XRD analysis results and SEM analysis results of titanium dioxide (TiO ₂ ) prepared through the recovery step, and Table 11 below shows that the purity of the finally prepared titanium dioxide (TiO ₂ ) is 99.9%. that showed the result.

[Manufactured titanium dioxide ( TiO ₂ ) purity] Unit: [wt%] Element TiO ₂ SiO ₂ Nb ₂ O ₅ Ca V Na Al Zr Fe Mg Mn Content 99.9 0.03 - - - - - - - - -

The above-described embodiments are examples for explaining the present invention, but the present invention is not limited thereto. Those skilled in the art to which the present invention pertains will be able to practice the present invention with various modifications therefrom, so the technical protection scope of the present invention should be defined by the appended claims.

Claims (9)

Obtaining a raw material by removing iron (Fe) from a mineral containing iron (Fe), silicon (Si), niobium (Nb), and titanium (Ti);
removing impurities by first removing silicon (Si) from the raw material and performing solid-liquid separation to obtain a residue containing Na ₂ TiO ₃ ;
A leaching step of obtaining a leaching solution containing titanium (Ti) by adding a leaching solution to the residue;
an extraction step of obtaining valuable metals in the organic phase from which iron (Fe) and zinc (Zr) are removed by adding an acid extractant and a diluent to the leaching solution; and
A recovery step of obtaining titanium (Ti) from which silicon (Si), niobium (Nb), and sodium (Na) are removed by adding a stripping solution to the valuable metal;
In the impurity removal step,
A soda roasting step of phase-changing the raw material into a soluble compound by adding at least one salt selected from sodium hydroxide (NaOH), sodium carbonate (Na ₂ CO ₃₎ , sodium nitrate (NaNO ₃₎ and sodium sulfate (Na ₂ SO ₄₎ ; and
A water leaching step of removing impurities by adding distilled water after the soda roasting,
Repeating the soda roasting step and the water leaching step at least twice,
In the extraction step,
The acid extracting agent is selected from the group consisting of bis-(2-ethylhexyl) phosphoric acid (D2EHPA), 2-ethylhexyl phosphonic acid mono-2-ethylhexyl phosphoric ester, tri-alkyl phosphine oxide and tri-octyl phosphine oxide,
The diluent includes xylene and kerosene,
In the recovery step, titanium (Ti) is removed through a countercurrent multi-stage stripping process by stripping solution treatment,
The titanium (Ti) removal rate obtained through the stripping process can be obtained through the following formula,
[formula]
(Concentration of valuable metals removed ÷ O/A ratio) ÷ Concentration of valuable metal titanium (Ti) in the organic phase
(The O/A ratio represents the ratio of the organic phase to the aqueous phase.)
A drying step of hydrolyzing the recovery solution obtained through the countercurrent multi-stage stripping process and drying titanium (Ti) precipitated by the hydrolysis to form a precipitate;
A washing step of treating the precipitate with a washing solution having a pH of 2 to 5, wherein the washing solution includes distilled water and removes chloride ions (Cl ^- ) in the precipitate through the washing; and
Selective recovery method of titanium (Ti) through hydrometallurgy, characterized in that it further comprises a calcination step of calcining at 600 ~ 700 ℃ after the washing step. delete In paragraph 1,
In the impurity removal step,
Titanium through hydrometallurgy, characterized in that the residue further contains silicon dioxide (SiO ₂ ), niobium pentoxide (Nb ₂ O ₅ ), zirconium dioxide (ZrO ₂ ) and iron oxide (Fe ₂ O ₃ ) Ti) selective recovery method. In paragraph 1,
The leachate in the leaching step includes hydrochloric acid (HCl),
The selective recovery method of titanium (Ti) through hydrometallurgy, characterized in that the leaching solution further contains silicon (Si), niobium (Nb), sodium (Na), zinc (Zr) and iron (Fe). delete In paragraph 1,
The concentration of titanium (Ti) in the organic phase in the extraction step can be obtained through the following concentration formula,
[formula]
(Titanium (Ti) initial concentration x extraction rate) ÷ O/A ratio
(The O/A ratio represents the ratio of the organic phase to the aqueous phase.)
Selective recovery method of titanium (Ti) through hydrometallurgy, characterized in that the number of steps for extracting the titanium (Ti) in the organic phase is changed according to the O / A ratio in the formula. In paragraph 1,
The stripping solution in the recovery step is a selective recovery method of titanium (Ti) through hydrometallurgy, characterized in that selected from the group consisting of distilled water, hydrochloric acid (HCl) and sodium chloride (NaCl). delete delete

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