Method for inhibiting hydrolysis of leached low-concentration titaniferous solution

Abstract

The invention discloses a method for inhibiting hydrolysis of a leached low-concentration titaniferous solution. The method comprises the steps that the F value of the low-concentration titaniferous solution is adjusted to be 1.70-1.98, the total titanium concentration is 87.72 g / L to 150 g / L according to the mass of titanium dioxide, and the temperature is 0 DEG C to 55 DEG C. On the basis of an existing sulfuric acid method titanium dioxide process technology, indexes and system properties for leaching the low-concentration titanium solution are regulated and controlled by regulating and controlling the total titanium concentration, the titanium solution temperature and the titanium solution reducibility, hydrolysis of the low-concentration titanium solution is inhibited, poor crystals and colloidal particles are prevented from being formed, a high-quality dilute titanium solution raw material is provided for a hydrolysis section, and the production cost is reduced. The method is simple in process, low in cost and good in hydrolysis inhibition effect when the low-concentration titanium solution is leached.

Description

Technical Field

[0001] The present application relates to the technical field of titanium dioxide preparation, and in particular to a method for inhibiting the hydrolysis of leached low-concentration titanium solution. Background Art

[0002] China leads the world in titanium resource processing, with the Panzhihua region boasting the largest reserves. However, due to its high calcium and magnesium content, titanium dioxide production primarily relies on the sulfuric acid process. Titanium concentrate undergoes acid hydrolysis to produce an acid-solidified solid phase, which is then leached to produce a low-concentration dilute titanium solution with a total titanium concentration generally ranging from 100 to 150 g / L. This solution undergoes filtration, iron removal, and concentration to achieve a hydrolyzed titanium solution that meets production requirements. Due to the low total titanium concentration, free sulfuric acid concentration, and system viscosity, the leached solution can be susceptible to concentration fluctuations, local saturation, impurity ion induction, and temperature fluctuations. This can enhance the tendency of titanium oxide clusters (Ti-O-Ti) to form condensation, triggering hydrolysis nucleation. This leads to premature hydrolysis during leaching and subsequent processing, resulting in undesirable crystallization and colloidal particles, posing a threat to the titanium dioxide production process. These hazards are mainly reflected in the following aspects: (1) These early hydrolysis products will interfere with the hydrolysis crystallization process, forming irregular crystal nuclei, resulting in uneven particle size distribution of TiO2 products, increased lattice defects, and reduced product brightness and pigment performance; (2) Because the early hydrolysis products have small particles, large specific surface area, and strong adsorption capacity, they will adsorb other particles or colloidal impurities, hindering the crystallization of TiO2. 2+ Ions diffuse to the surface of H2TiO3 particles, affecting the uniformity of the hydrolysis reaction, forming local supersaturated zones, triggering disordered nucleation, and resulting in uneven composition and structure of the TiO2 product; (3) Early hydrolysis products also reduce the stability of the TiOSO4 solution and accelerate the premature hydrolysis of the TiOSO4 solution, thereby forming products with enhanced colloidal properties, which increases the difficulty of subsequent washing; (4) Early hydrolysis products will also aggravate calcination defects, because impurities remaining during the calcination process (such as iron, silicon, etc.) will cause lattice distortion, leading to sintering and hardening of TiO2 particles, thereby reducing the dispersibility and optical properties of the TiO2 product.

[0003] Therefore, it is necessary to adopt effective methods to inhibit the hydrolysis of leached low-concentration titanium liquid, avoid the production of undesirable crystals and colloidal particles, and promote the high-quality development of the titanium dioxide industry. Summary of the Invention

[0004] In view of this, the present application provides a method for inhibiting the hydrolysis of low-concentration titanium liquid during leaching, which adopts the methods of regulating the total titanium concentration, controlling the temperature of the titanium liquid, controlling the reducibility of the titanium liquid, adding stabilizers, etc. to regulate the indicators and system properties of the low-concentration titanium liquid during leaching, inhibit the hydrolysis of the low-concentration titanium liquid, avoid the formation of undesirable crystals and colloidal particles, and provide high-quality dilute titanium liquid raw materials for the hydrolysis section.

[0005] The present application provides a method for inhibiting hydrolysis of leached low-concentration titanium solution, the method comprising:

[0006] Adjust the F value of the low-concentration titanium solution to 1.70 to 1.98, the total titanium concentration (based on the mass of titanium dioxide) to 87.72 g / L to 150 g / L, and the temperature to 0°C to 55°C. The F value is (sulfuric acid concentration bound to titanium + free sulfuric acid concentration) / TiO2 concentration.

[0007] In some specific implementations, the trivalent titanium concentration of the adjusted low-concentration titanium liquid is 2.14 g / L to 5.20 g / L.

[0008] In some specific implementations, the adjustment method includes adding waste titanium dioxide acid. The waste titanium dioxide acid acts as a stabilizer, adding it to the low-concentration titanium solution to achieve a free acid concentration of 65 g / L or above, thereby inhibiting hydrolysis of the titanium solution. In some specific implementations, the volume of the waste titanium dioxide acid is 2% to 14% of the volume of the low-concentration titanium solution. In some specific implementations, the mass concentration of the waste titanium dioxide acid is 18% to 22%.

[0009] In some specific implementations, the temperature is 20°C to 55°C.

[0010] In some specific implementations, the F value of the low-concentration titanium liquid is 1.65 to 1.95.

[0011] In some specific implementations, the total titanium concentration of the low-concentration titanium liquid is 80 g / L to 150 g / L based on the mass of titanium dioxide.

[0012] In some specific implementations, the trivalent titanium concentration of the low-concentration titanium liquid is 0.1 g / L to 5 g / L.

[0013] In some specific implementations, the concentration of free sulfuric acid in the adjusted low-concentration titanium solution is 65 g / L to 300 g / L.

[0014] Based on the existing sulfuric acid method titanium dioxide process technology, the present application adopts the method of controlling the total titanium concentration, controlling the titanium liquid temperature, and controlling the reducibility of the titanium liquid to control the indicators and system properties of the leaching of low-concentration titanium liquid, inhibiting the hydrolysis of the low-concentration titanium liquid, avoiding the formation of undesirable crystals and colloidal particles, and providing high-quality dilute titanium liquid raw materials for the hydrolysis stage. The method is simple in process, low in cost, and has a good hydrolysis inhibition effect on the leaching of low-concentration titanium liquid. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a fitting curve diagram of absorbance and hydrolyzed TiO2 concentration in Example 1 of the present application. DETAILED DESCRIPTION

[0016] It should be understood that the expression "one or more of" includes individually each of the items recited after the expression and various combinations of two or more of the recited items, unless otherwise apparent from the context and usage. The expression "and / or" in conjunction with three or more recited items should be understood to have the same meaning, unless otherwise apparent from the context.

[0017] The terms "comprising", "having" or "containing", including their grammatical synonyms, should generally be understood as open and non-restrictive, e.g., not excluding other unrecited elements or steps, unless otherwise specifically stated or understood from the context.

[0018] It should be understood that the order of steps or the order in which certain actions are performed is not important as long as the application remains operable. Additionally, two or more steps or actions may be performed simultaneously.

[0019] The use of any and all examples or exemplary language such as "for example" or "including" herein is intended only to better illustrate the present application and does not limit the scope of the present application. No language in this specification should be construed as indicating any non-claimed element is essential to the practice of the present application.

[0020] In addition, the numerical ranges and parameters used to define this application are approximate values. The relevant numerical values ​​in the specific examples have been presented as accurately as possible. However, any numerical value inherently inevitably contains standard deviations due to individual testing methods. Therefore, unless otherwise expressly stated, it should be understood that all ranges, amounts, values, and percentages used in this disclosure are modified by the word "about." As used herein, "about" generally means that the actual value is within plus or minus 10%, 5%, 1%, or 0.5% of a particular value or range.

[0021] The present application provides a method for inhibiting hydrolysis of leached low-concentration titanium solution, the method comprising:

[0022] Adjust the F value of the low concentration titanium solution to 1.70 to 1.98 (can be 1.70, 1.72, 1.74, 1.76, 1.78, 1.80, 1.82, 1.84, 1.86, 1.88, 1.90, 1.92, 1.94, 1.95, 1.98), and the total titanium concentration is 87.72 g / L to 150 g / L (can be 87.72 g / L, 90 g / L, 95 g / L, 100 g / L, 110 g / L, 120 g / L, 130 g / L, 132 g / L, 133 g / L, 135 g / L, 138 g / L, 140 g / L, 142 g / L, 144 g / L, 146 g / L, 148 g / L, 150g / L), and the temperature is 0°C to 55°C (can be 0°C, 1°C, 5°C, 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C). The F value is (sulfuric acid concentration bound to titanium + free sulfuric acid concentration) / TiO2 concentration.

[0023] The total titanium concentration, the temperature and the reducibility of the titanium liquid are controlled to regulate the indicators and system properties of the leaching of low-concentration titanium liquid, inhibit the hydrolysis of the low-concentration titanium liquid and avoid the formation of undesirable crystals and colloidal particles.

[0024] In some specific implementations, the trivalent titanium concentration of the adjusted low-concentration titanium liquid is 2 g / L to 5 g / L, which can be 2 g / L, 2.5 g / L, 3 g / L, 3.5 g / L, 4 g / L, 4.5 g / L, 5 g / L, and is preferably 2.14 g / L to 3.42 g / L.

[0025] In some specific implementations, the adjustment method includes adding titanium dioxide waste acid. The titanium dioxide waste acid acts as a stabilizer and is added to the low-concentration titanium solution to obtain a free acid concentration of 65 g / L or more to inhibit the hydrolysis of the titanium solution. In some specific implementations, the volume of the titanium dioxide waste acid is 2% to 14% of the volume of the low-concentration titanium solution, and can be 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 12%, 13%, 14%, and preferably 2.5% to 14%. In some specific implementations, the mass concentration of the titanium dioxide waste acid is 18% to 22%, and can be 18%, 18.2%, 18.5%, 18.8%, 19%, 19.2%, 19.5%, 19.8%, 20%, 21%, 21.2%, 21.5%, 21.8%, 22%, and preferably 20%.

[0026] In some specific implementations, the temperature is 20° C. to 55° C., and can be 20° C., 25° C., 30° C., 35° C., 40° C., 45° C., 50° C., or 55° C. During storage and transportation of the extracted low-concentration titanium solution, its temperature is maintained at ≤ 55° C. The lower the temperature, the better the hydrolysis inhibition effect.

[0027] In some specific implementations, the F value of the low-concentration titanium liquid is 1.65 to 1.95, and can be 1.65, 1.68, 1.7, 1.75, 1.78, 1.8, 1.85, 1.88, 1.9, 1.92, or 1.95.

[0028] In some specific implementations, the total titanium concentration of the low-concentration titanium liquid is 80 g / L to 150 g / L based on the mass of titanium dioxide, and can be 80 g / L, 85 g / L, 90 g / L, 95 g / L, 100 g / L, 105 g / L, 110 g / L, 115 g / L, 120 g / L, 125 g / L, 130 g / L, 135 g / L, 140 g / L, 145 g / L, or 150 g / L. Controlling the trivalent titanium (TiO2) content in the low-concentration titanium liquid 3+ ) concentration, maintain the reducing property of titanium liquid system, avoid Fe 2+ Oxidized to Fe 3+ Induce hydrolysis to inhibit hydrolysis of titanium liquid.

[0029] In some specific implementations, the trivalent titanium concentration of the low-concentration titanium liquid is 0.1 g / L to 5 g / L, which can be 0.1 g / L, 0.15 g / L, 0.2 g / L, 0.25 g / L, 0.3 g / L, 0.35 g / L, 0.4 g / L, 0.45 g / L, or 0.5 g / L.

[0030] In some specific implementations, the concentration of free sulfuric acid in the adjusted low-concentration titanium liquid is 65 g / L to 300 g / L, and can be 65 g / L, 70 g / L, 75 g / L, 80 g / L, 85 g / L, 90 g / L, 95 g / L, 100 g / L, 120 g / L, 130 g / L, 150 g / L, 160 g / L, 180 g / L, 200 g / L, 210 g / L, 250 g / L, 260 g / L, 270 g / L, 280 g / L, 290 g / L, 295 g / L, or 300 g / L.

[0031] The comprehensive conditions that affect the hydrolysis of titanium liquid are defined as follows: as the temperature increases, the degree of hydrolysis increases; as the total titanium concentration decreases, the degree of hydrolysis increases; as the F value decreases, the degree of hydrolysis increases; as the trivalent titanium decreases, the degree of hydrolysis increases; adding titanium dioxide waste acid to the titanium liquid is mainly to increase the F value of the titanium liquid (increase the concentration of free sulfuric acid in the titanium liquid), thereby inhibiting the hydrolysis of the titanium liquid.

[0032] Based on the existing sulfuric acid method titanium dioxide process technology, the present application adopts the method of controlling the total titanium concentration, controlling the titanium liquid temperature, and controlling the reducibility of the titanium liquid to control the indicators and system properties of the leaching of low-concentration titanium liquid, inhibiting the hydrolysis of the low-concentration titanium liquid, avoiding the formation of undesirable crystals and colloidal particles, and providing high-quality dilute titanium liquid raw materials for the hydrolysis stage. The method is simple in process, low in cost, and has a good hydrolysis inhibition effect on the leaching of low-concentration titanium liquid.

[0033] The present application is further described below with reference to the following examples. The scope of protection of the present application is not limited by the following examples.

[0034] Example 1

[0035] This embodiment provides a method for inhibiting hydrolysis of leached low-concentration titanium solution, comprising:

[0036] The total titanium concentration is 100 g / L, the F value is 1.65, and the trivalent titanium (Ti 3+ ) concentration of 3.42 g / L leached low-concentration titanium solution, add 20% titanium dioxide waste acid (the volume of titanium dioxide waste acid is 14% of the low-concentration titanium solution), the F value is 1.97, trivalent titanium (Ti 3+ ) concentration is 3.00 g / L, the total titanium concentration is 87.72 g / L, and the titanium liquid temperature is maintained at 55℃.

[0037] Examples 2-8

[0038] Examples 2-8 respectively provide a method for inhibiting the hydrolysis of leached low-concentration titanium solution, and the parameters are shown in Table 2.

[0039] Comparative Examples 1-7

[0040] Comparative Examples 1-7 respectively provide a method for inhibiting the hydrolysis of leached low-concentration titanium solution, and the parameters are shown in Table 2.

[0041] The titanium liquid provided in Examples 1-8 and Comparative Examples 1-7 was stored for one day and the hydrolysis rate was tested. The test method was as follows:

[0042] The concentration of nanoparticles at low concentrations is determined by measuring absorbance, and an ISO standard has been established. The hydrolysis rate of low-concentration titanium solution is calculated using the equation relating absorbance to the concentration of early hydrolyzed particles.

[0043] Using low-concentration titanium dioxide leaching solution and hydrolyzed metatitanic acid from a titanium dioxide manufacturer as raw materials, with a total titanium concentration of 150 g / L, other indicators included an F value of 1.95, 2.78 g / L trivalent titanium, and a TiO2 content of 29.12% in the metatitanic acid. A standard curve comparing absorbance and hydrolyzed TiO2 concentration was established spectrophotometrically. The following steps were performed: 269.8 mg of metatitanic acid was weighed and added to 100 mL of the titanium dioxide solution of the aforementioned concentration. Ultrasonic dispersion (ultrasonic frequency 40 kHz, ultrasonic power 100 W) was performed and mixed to obtain a mixed titanium solution containing hydrolyzed metatitanic acid particles. At room temperature, a certain volume of the mixed titanium solution was transferred to a 100 mL volumetric flask. 2 mL of 84% (mass percent) aqueous sulfuric acid was added to inhibit hydrolysis of the diluted titanium solution. Water was then added in portions, shaken and mixed thoroughly, and the volume was brought to the mark on the flask. Using a UV-visible spectrophotometer, the absorbance of the diluted titanium solution was measured at a wavelength of 565 nm, using the same diluted titanium solution obtained by diluting the above titanium solution without metatitanic acid as a reference (the absorbance value was set to 0). An equation was established to determine the relationship between absorbance and hydrolyzed TiO₂ concentration. The absorbance of each diluted titanium solution was measured, as shown in Table 1.

[0044] Table 1

[0045]

[0046] The concentration of hydrolyzed TiO2 was plotted against absorbance, and the fitting curve of absorbance and hydrolyzed TiO2 concentration was as follows: Figure 1 As shown. At this concentration (total titanium concentration 150 g / L), the absorbance (A1) is linearly correlated with the TiO2 concentration (C), with a high degree of fit (R 2 =0.99921). The relationship between the two is as follows:

[0047] A1 = 0.00481 + 0.08211*C, R 2 =0.99921 (1)

[0048] The determination and calculation method of the hydrolysis rate of the titanium liquid at this concentration can be established from equation (1), as shown in equation (2).

[0049] Hydrolysis rate = (A1 - 0.00481) / 0.08211 × dilution factor / C 钛液1 × 100% (2)

[0050] Where, the dilution factor refers to the dilution ratio corresponding to the dilution of a certain concentration volume of titanium solution to 100 mL, C 钛液1 Refers to the total titanium concentration of the titanium liquid.

[0051] This method was also used for the leaching of other low-concentration titanium solutions with different concentrations and indicators. The relationship between the hydrolysis rate and absorbance was established by referring to equation (2). The corresponding hydrolysis rate was calculated by measuring the absorbance at a certain dilution multiple.

[0052] The test results are shown in Table 2.

[0053] Table 2

[0054]

[0055] It can be seen from the data in Table 2 that according to the method for inhibiting the hydrolysis of leached low-concentration titanium liquid as described in the present application, the hydrolysis rate of the low-concentration titanium liquid can be reduced to below 0.5%. In the method provided in Comparative Example 1, the F value is 1.65, and no titanium dioxide waste acid is added for adjustment. Its hydrolysis rate is 3.68, which is significantly worse than that in Example 1.

[0056] In the method provided in Comparative Example 2, the temperature was set to 70° C., and the hydrolysis rate was increased to 2.82%.

[0057] In the method provided in Comparative Example 3, the temperature was set to 65° C. and the hydrolysis rate was 1.88%, which was lower than that in Comparative Example 2 and significantly worse than that in Example.

[0058] In the method provided in Comparative Example 4, the temperature was adjusted to 58° C., and the hydrolysis rate was better than that of Comparative Examples 2 and 3, but significantly worse than that of the embodiment.

[0059] The F value in the method provided in Comparative Example 5 is 1.65, which does not meet the requirements of this solution, and the hydrolysis rate is 1.24%.

[0060] In the method provided in Comparative Example 6, the concentration of trivalent titanium is 0 g / L, and the hydrolysis rate is 0.86%, which does not meet the requirement of being less than 0.5%.

[0061] The F value in the method provided in Comparative Example 7 is 1.67, which does not meet the requirements of this solution. At the same time, the temperature is 60° C. and the hydrolysis rate is 2.03%.

[0062] The above is only a preferred specific implementation method of the present application, but the scope of protection of the present application is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes based on the technical solution and application concept of the present application within the technical scope disclosed in the present application, and they should be covered by the scope of protection of the present application.

Claims

1. A method for inhibiting hydrolysis of leached low-concentration titanium solution, characterized in that: The method comprises: The F value of the low-concentration titanium solution is adjusted to 1.70 to 1.98, the total titanium concentration is adjusted to 87.72 g / L to 150 g / L based on the mass of titanium dioxide, and the temperature is adjusted to 0°C to 55°C.

2. The method according to claim 1, characterized in that The trivalent titanium concentration of the adjusted low-concentration titanium solution is 2.14 g / L to 5.20 g / L.

3. The method according to claim 1, characterized in that The adjustment method includes adding titanium dioxide waste acid.

4. The method according to claim 3, characterized in that The volume of the titanium dioxide waste acid is 2% to 14% of the volume of the low-concentration titanium liquid.

5. The method according to claim 3, characterized in that The mass concentration of the titanium dioxide waste acid is 18% to 22%.

6. The method according to claim 1, characterized in that The temperature is 20°C to 55°C.

7. The method according to claim 1, characterized in that The F value of the low-concentration titanium liquid is 1.65 to 1.

95.

8. The method according to claim 1, characterized in that The total titanium concentration of the low-concentration titanium liquid is 80 g / L to 150 g / L based on the mass of titanium dioxide.

9. The method according to claim 1, characterized in that The trivalent titanium concentration of the low-concentration titanium liquid is 0.1 g / L to 5 g / L.

10. The method according to claim 1, characterized in that The concentration of free sulfuric acid in the adjusted low-concentration titanium solution is 65 g / L to 300 g / L.

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