Method for rapidly improving resistivity of titanium dioxide

Abstract

The invention discloses a method for rapidly improving the resistivity of titanium dioxide, and particularly relates to the technical field of titanium dioxide production. The method comprises the steps that a sulfuric acid method titanium dioxide production technology is adopted, an obtained product is pulped and washed, an aluminum-containing substance is added in the pulping and washing process to serve as an additive, and the adding amount of the aluminum-containing additive accounts for 1.0-3.0 wt% of the content of titanium dioxide. Compared with titanium dioxide produced in the prior art, the average resistivity value of the titanium dioxide produced by the method disclosed by the invention is maximally improved by 180 omega.m, meanwhile, the lightening power, the covering power, the whiteness, the oil absorption and the pH of the titanium dioxide are not influenced, and the titanium dioxide meets the application requirements. The resistivity of the obtained titanium dioxide is 200-240 omega.m, the pH value is 6.5-7.5, and the lightening power is greater than or equal to 105.

Description

Technical Field

[0001] The present invention relates to the technical field of titanium dioxide production, and particularly relates to a method for rapidly increasing the resistivity of titanium dioxide. Background Art

[0002] Titanium dioxide is an important inorganic chemical pigment, and its main component is titanium dioxide. The production processes of titanium dioxide include two process routes: the sulfuric acid method and the chlorination method. It has important uses in industries such as coatings, inks, papermaking, plastics, rubber, chemical fibers, and ceramics.

[0003] The sulfuric acid method has the characteristics of mature process route, low requirements for equipment and devices, and low requirements for raw materials. Moreover, it can produce two products: rutile type and anatase type. The production of titanium dioxide by the sulfuric acid method mainly includes steps such as hydrolysis of concentrated titanium liquid, washing, bleaching, salt treatment, and rotary kiln calcination. The resistivity of titanium dioxide produced by the existing sulfuric acid method is 23 - 30 Ω·m, and indexes such as pH value, whiteness, oil absorption, and water dispersibility basically meet the application requirements. Due to the low resistivity of titanium dioxide produced by the existing method, the wide application of titanium dioxide in some industries is restricted.

[0004] Chinese Patent CN102515267A, a method for producing titanium dioxide with high resistivity, adopts the sulfuric acid method titanium dioxide production process, including the following steps: hydrolysis of titanium liquid, washing, salt treatment, and calcination to produce powder. Among them: in the salt treatment step, a potassium-containing substance is added, and the addition amount of the potassium-containing substance accounts for 0.39 - 0.47 wt% of the titanium dioxide content. Among them, the potassium-containing substance is a potassium-containing base or salt. Using the method of the present invention to produce titanium dioxide, the resistivity of the obtained titanium dioxide is 900 Ω·cm higher than that of titanium dioxide produced by the prior art. However, the increased resistivity of titanium dioxide is limited, which restricts the wide application of titanium dioxide in some industries. Summary of the Invention

[0005] Therefore, the present invention provides a method for rapidly increasing the resistivity of titanium dioxide to solve the problems in the prior art.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] According to a method for rapidly increasing the resistivity of titanium dioxide provided by the present invention, the method includes adopting the sulfuric acid method titanium dioxide production process, and the obtained product is subjected to pulping and washing. Among them, an aluminum-containing substance is added as an additive during the pulping and washing process, and the addition amount of the aluminum-containing additive accounts for 1.0 - 3.0 wt% of the titanium dioxide content.

[0008] Further, the aluminum-containing additive is an aluminum-containing base or salt.

[0009] Further, the aluminum-containing additive is one or more of aluminum carbonate, aluminum sulfate, sodium metaaluminate, and alum.

[0010] Further, in the beating and washing process, the concentration of titanium dioxide is adjusted to 40-50 wt%.

[0011] Further, in the beating and washing process, a neutralizing agent is also added.

[0012] Further, in the beating and washing process, an aluminum-containing additive is added first, and then a neutralizing agent is added.

[0013] Further, the neutralizing agent is a common acid-base neutralizing agent.

[0014] Further, the beating and washing process requires heating and stirring first, then adding an aluminum-containing additive, and finally adding a neutralizing agent.

[0015] Further, after the beating and washing, solid-liquid separation is carried out, and then washing is carried out until the resistivity of the washing water is qualified.

[0016] Further, the resistivity of the titanium dioxide is 200-240 Ω·m, pH = 6.5-7.5, and the tinting strength ≥ 105.

[0017] As an example, a method for quickly increasing the resistivity of titanium dioxide specifically comprises the following steps:

[0018] S1. Pulp preparation and dispersion: Take the titanium dioxide base material, add deionized water and disperse it evenly to prepare a 40-50 wt% titanium dioxide slurry;

[0019] S2. Heating treatment: Place it on a heating plate, heat the slurry under stirring, add an aluminum-containing additive, and then add a neutralizing agent;

[0020] S3. Plate-frame filtration: Pump the titanium dioxide slurry into a small plate-frame filter press for solid-liquid separation, and wash until the resistivity of the washing water is qualified.

[0021] The present invention has the following advantages:

[0022] The average value of the resistivity of the titanium dioxide produced by the method of the present invention is increased by up to 180 Ω·m compared with the titanium dioxide produced by the prior art. At the same time, its tinting strength, covering power, whiteness, oil absorption, and pH are not affected, and the present invention meets the application requirements. The resistivity of the titanium dioxide obtained by the present invention is 200-240 Ω·m, pH = 6.5-7.5, and the tinting strength ≥ 105.

[0023] The production method of the present invention is simple and easy to implement, has low energy consumption, and strong feasibility. Specific embodiments

[0024] The following specific embodiments illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0025] A method for rapidly increasing the resistivity of titanium dioxide, the specific steps are as follows:

[0026] S1. Pulp making and dispersion: Take the titanium dioxide base material, add deionized water and disperse it evenly to prepare a 40 - 50wt% titanium dioxide slurry.

[0027] S2. Heat treatment: Place it on a heating plate, heat the slurry under stirring, add an aluminum-containing additive, and then add a neutralizing agent.

[0028] S3. Plate and frame filtration: Pump the titanium dioxide slurry into a small plate and frame filter press for solid-liquid separation, and wash until the resistivity of the washing water is qualified.

[0029] In the process of making pulp in the present invention, high-speed mechanical stirring is adopted to make titanium dioxide disperse evenly in deionized water. Preferably, in step S1, the titanium dioxide base material is pigment-grade anatase titanium dioxide, and the average particle size of the titanium dioxide base material is ≤0.250μm. Preferably, in step S1, the titanium dioxide base material is added to deionized water for pulp making, and the slurry concentration is controlled at 40 - 50wt%. Preferably, in step S2, the slurry is heated to near boiling under stirring, and the holding time is preferably 20 - 30min, and then the aluminum-containing additive is added. Preferably, in step S2, the addition amount of the aluminum-containing additive is calculated as Al 2 O 3 and is 1.0 - 3.0wt% of the titanium dioxide content. Preferably, in step S2, the aluminum-containing additive is at least one of aluminum carbonate, aluminum sulfate, sodium metaaluminate, and alum. Preferably, in step S2, a neutralizing agent is added until the pH of the slurry is 6.5 - 7.5. Preferably, in step S3, the water content of the slurry after being filtered by the small plate and frame filter press is 18 - 21%, and the washed filter cake is dried and pulverized after removing a large amount of soluble ions.

[0030] Example 1

[0031] This example provides a method for rapidly increasing the resistivity of titanium dioxide:

[0032] (1) Take 2000g of SWA-100 type titanium dioxide, add 2000ml of 90°C deionized water, and stir at high speed to make it disperse evenly to obtain a 50wt% titanium dioxide slurry.

[0033] (2) Place the above-mentioned slurry on a graphite heating plate, heat it to near boiling under stirring, add 1.0% sodium metaaluminate (0.2 mol / L), and the addition time is 10 min. Then add 1.6 wt% H 2 SO 4 Adjust the pH of the slurry to 7.0;

[0034] (3) Pump the above-prepared slurry into a small plate and frame filter press through a diaphragm pump, add 6000 ml of deionized water for washing, and dry it with compressed air until the water content is 18 - 20%;

[0035] (4) Put the above filter cake into a blast drying oven at 105 °C and dry it for 4 h, then crush it to obtain the product.

[0036] The resistivity of the product is 240 Ω·m, pH = 7.0, and the tinting strength is 107.

[0037] Example 2

[0038] This example provides a method for rapidly increasing the resistivity of titanium dioxide:

[0039] (1) Take 2000 g of SWA-100 type titanium dioxide, add it to 3000 ml of 85 °C deionized water, and stir it at high speed to make it disperse evenly to obtain a 40 wt% titanium dioxide slurry;

[0040] (2) Place the above-mentioned slurry on a graphite heating plate, heat it to near boiling under stirring, add 1.0% sodium metaaluminate (0.2 mol / L), and the addition time is 10 min. Then add 1.6 wt% H 2 SO 4 Adjust the pH of the slurry to 7.0;

[0041] (3) Pump the above-prepared slurry into a small plate and frame filter press through a diaphragm pump, add 6000 ml of deionized water for washing, and dry it with compressed air until the water content is 18 - 20%;

[0042] (4) Put the above filter cake into a blast drying oven at 105 °C and dry it for 4 h, then crush it to obtain the product.

[0043] The resistivity of the product is 240 Ω·m, pH = 7.0, and the tinting strength is 111.

[0044] Example 3

[0045] This example provides a method for rapidly increasing the resistivity of titanium dioxide:

[0046] (1) Take 2000 g of SWA-100 type titanium dioxide, add it to 3000 ml of 85 °C deionized water, and stir it at high speed to make it disperse evenly to obtain a 45 wt% titanium dioxide slurry;

[0047] (2) Place the above-mentioned slurry on a graphite heating plate, heat it to near boiling under stirring, add 1.0% aluminum sulfate (0.1 mol / L), and the addition time is 10 min. Then add 1.6 wt% H 2 SO 4 Adjust the pH of the slurry to 6.5;

[0048] (3) Pump the above-prepared slurry into a small plate-and-frame filter press through a diaphragm pump, add 6000 ml of deionized water for washing, and dry it with compressed air until the water content is 18 - 20%;

[0049] (4) Put the above filter cake into a blast drying oven at 105 °C and dry it for 4 h, and then crush it to obtain the product.

[0050] The resistivity of the product is 240 Ω·m, pH = 6.6, and the tinting strength is 108.

[0051] Comparative Example 1

[0052] This comparative example provides a method for quickly increasing the resistivity of titanium dioxide, which treats titanium dioxide without heating and without additives. Specifically:

[0053] (1) Take 2000 g of SWA-100 type titanium dioxide, add it to 2000 ml of normal-temperature deionized water, and stir it at high speed to make it evenly dispersed to obtain a 50 wt% titanium dioxide slurry;

[0054] (2) Pump the above slurry into a small plate-and-frame filter press through a diaphragm pump, add 6000 ml of deionized water for washing, and dry it with compressed air until the water content is 18 - 20%;

[0055] (3) Put the above filter cake into a blast drying oven at 105 °C and dry it for 4 h, and then crush it to obtain the product.

[0056] The resistivity of the product is 55 Ω·m, pH = 7.4, and the tinting strength is 107.

[0057] Comparative Example 2

[0058] This comparative example provides a method for quickly increasing the resistivity of titanium dioxide, which treats titanium dioxide under heating conditions without additives. Specifically:

[0059] (1) Take 2000 g of SWA-100 type titanium dioxide, add it to 2000 ml of 90 °C deionized water, and stir it at high speed to make it evenly dispersed to obtain a 50 wt% titanium dioxide slurry;

[0060] (2) Place the above slurry on a graphite heating plate, heat it to near boiling under stirring, and keep it for 30 min;

[0061] (3) Pump the slurry prepared above into a small plate and frame filter press through a diaphragm pump, add 6000 ml of deionized water for washing, and dry it with compressed air until the water content is 18 - 20%;

[0062] (4) Put the above filter cake into a blast drying oven at 105 °C and dry it for 4 h, and obtain the product after pulverization.

[0063] The resistivity of the product is 62 Ω·m, pH = 7.3, and the tinting strength is 107.

[0064] Comparative Example 3

[0065] Existing titanium dioxide manufacturer: Sansheng Titanium; batch number SA50: resistivity is 65 Ω·m, pH = 7.25, and tinting strength is 108.

[0066] Comparative Example 4

[0067] The product prepared by the preparation method of Example 1 of Patent CN102515267A, the resistivity of the product is 34 Ω·m, pH = 7.2, and the tinting strength is 108.

[0068] Experimental Example 1

[0069] Measure the indexes such as whiteness, oil absorption, and water dispersibility of the products of Examples 1 - 3 and Comparative Examples 1 - 4, and the results are shown in Table 1.

[0070] Table 1

[0071] Whiteness Oil absorption Water dispersibility Example 1 98.90 18 80 Example 2 98.95 19 80 Example 3 99.01 18 80 Comparative Example 1 98.50 18 80 Comparative Example 2 98.67 18 80 Comparative Example 3 99.00 2.65 91.81 Comparative Example 4 98.91 2.67 91.77

[0072] It can be seen that the resistivity of the products obtained in Examples 1 - 3 of the present invention reaches 240 Ω·m, which is greatly improved compared with the titanium dioxide produced by the existing process, and the indexes such as pH value, whiteness, oil absorption, and water dispersibility basically meet the application requirements. Although Comparative Examples 1 - 2 cannot quickly improve the resistivity of titanium dioxide, they can be used as a reference for washing away soluble salt ions.

[0073] Although the present invention has been described in detail with general descriptions and specific embodiments above, based on the present invention, some modifications or improvements can be made, which are obvious to those skilled in the art. Therefore, these modifications or improvements made without departing from the spirit of the present invention all belong to the scope protected by the present invention.

Claims

1. A method for rapidly increasing the resistivity of titanium dioxide, characterized in that: The method comprises adopting a sulfuric acid method titanium dioxide production process, and beating and washing the obtained product, wherein aluminum-containing substances are added as additives during the beating and washing process, and the amount of the aluminum-containing additive added accounts for 1.0-3.0wt% of the titanium dioxide content.

2. A method for rapidly increasing the resistivity of titanium dioxide according to claim 1, characterized in that: The aluminum-containing additive is an aluminum-containing alkali or salt.

3. A method for rapidly increasing the resistivity of titanium dioxide according to claim 2, characterized in that: The aluminum-containing additive is one or more of aluminum carbonate, aluminum sulfate, sodium metaaluminate, and alum.

4. A method for rapidly increasing the resistivity of titanium dioxide according to claim 1, characterized in that: During the beating and washing, the concentration of titanium dioxide is adjusted to 40-50 wt %.

5. A method for rapidly increasing the resistivity of titanium dioxide according to claim 1, characterized in that: During the beating and washing, a neutralizing agent is also added.

6. A method for rapidly increasing the resistivity of titanium dioxide according to claim 5, characterized in that: In the pulping and washing, the aluminum-containing additive is added first, and then the neutralizing agent is added.

7. A method for rapidly increasing the resistivity of titanium dioxide according to claim 6, characterized in that: The neutralizer is a common acid-base neutralizer.

8. A method for rapidly increasing the resistivity of titanium dioxide according to claim 7, characterized in that: The pulping and washing process requires heating and stirring first, then adding the aluminum-containing additive, and finally adding the neutralizing agent.

9. A method for rapidly increasing the resistivity of titanium dioxide according to claim 8, characterized in that: After the pulping and washing, solid-liquid separation is performed and then washing is performed until the resistivity of the washing water is qualified.

10. A method for rapidly increasing the resistivity of titanium dioxide according to claim 6, characterized in that: The titanium dioxide has a resistivity of 200-240Ω·m, a pH of 6.5-7.5, and a decolorizing power of ≥105.