Method for producing titanium dioxide with high covering power at low cost

Abstract

The invention discloses a low-cost method for producing titanium dioxide with high covering power, and belongs to the technical field of titanium dioxide production. The invention solves the problem of how to reduce the production cost of the titanium dioxide with high covering power. In the process of salt treatment of metatitanic acid slurry, the addition amount of salt treatment is as follows: the addition amount of phosphorus salt is 0.15% of the mass of TiO2 in the metatitanic acid slurry according to the mass of P2O5; based on the mass of K2O, the addition amount of the potassium salt is 0.18-0.2% of the mass of TiO2 in the metatitanic acid slurry; on the basis of the mass of Al2O3, the addition amount of the aluminum salt is 0.25-0.3% of the mass of TiO2 in the metatitanic acid slurry. The morphology of titanium dioxide particles is optimized by reducing the addition amount of the salt treatment agent, so that the obtained titanium dioxide particles are spherical, the particle size distribution of calcined titanium dioxide is regulated and controlled, the covering power of titanium dioxide is enhanced, and the production cost is effectively reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of titanium dioxide production, and particularly relates to a method for producing high-hiding titanium dioxide at low cost. Background Art

[0002] When producing pigment titanium dioxide, in order to form smooth, regular and excellent pigment particles during the calcination of rutile-type titanium dioxide, and to meet the special requirements of this grade of titanium dioxide, some regulators need to be added to metatitanic acid. Through salt treatment, not only can the calcination temperature be reduced, the calcination process of metatitanic acid be controlled, and the morphology of titanium dioxide particles be adjusted to make the calcined product have good hue, gloss, coloring power, oil absorption, as well as appropriate crystal grain shape, dispersion performance and hiding power.

[0003] The invention with the patent number CN106395893B discloses a method for preparing titanium dioxide for high-hiding laminated paper, and its hiding rate reaches more than 96% by adding phosphate, potassium salt and aluminum salt as salt treatment agents. On this basis, how to further reduce the production cost of high-hiding titanium dioxide is a problem to be solved in this field. Summary of the Invention

[0004] Aiming at the problem of how to further reduce the production cost of high-hiding titanium dioxide in the prior art, the present invention provides a method for producing high-hiding titanium dioxide at low cost.

[0005] The technical solution adopted by the present invention is as follows:

[0006] A method for producing high-hiding titanium dioxide at low cost, during the salt treatment process of metatitanic acid slurry, the addition amounts of salt treatment are as follows:

[0007] Calculated by the mass of K 2 O, the addition amount of potassium salt is 0.18 - 0.2% of the mass of TiO 2 in the metatitanic acid slurry;

[0008] Calculated by the mass of P 2 O 5 , the addition amount of phosphate is 0.15% of the mass of TiO 2 in the metatitanic acid slurry;

[0009] Calculated by the mass of Al 2 O 3 , the addition amount of aluminum salt is 0.25 - 0.3% of the mass of TiO 2 in the metatitanic acid slurry.

[0010] After adopting this technical solution, the particle morphology of titanium dioxide mainly has three types: spherical, conical, and plate-shaped. Among them, the spherical particles have a relatively small surface area of the particles, good light scattering and reflection properties, so they perform well in the manufacture of high-quality paints, and can improve their gloss and hiding power. The present invention optimizes the morphology of titanium dioxide particles by reducing the addition amount of the salt treatment agent, so that the obtained titanium dioxide particles are spherical, thereby controlling the particle size distribution of calcined titanium dioxide, enhancing the hiding power of titanium dioxide, and effectively reducing the production cost after reducing the amount of the salt treatment agent.

[0011] Preferably, the concentration of TiO 2 in the metatitanic acid slurry is 40 - 370 g / L.

[0012] Preferably, the phosphate salt is phosphoric acid, the potassium salt is potassium hydroxide, and the aluminum salt is aluminum sulfate.

[0013] Preferably, based on the mass of K 2 O, the addition amount of the potassium salt is 0.19% of the mass of TiO 2 in the metatitanic acid slurry, and based on the mass of Al 2 O 3 the addition amount of the aluminum salt is 0.27% of the mass of TiO 2 in the metatitanic acid slurry.

[0014] Preferably, the order of adding the phosphate salt, potassium salt, and aluminum salt is potassium salt, phosphate salt, and aluminum salt in sequence.

[0015] Preferably, when adding the phosphate salt, potassium salt, and aluminum salt, different salt treatment agents are added at an interval of 8 - 12 minutes.

[0016] After adopting this technical solution, in the salt treatment process of producing anatase-type pigment titanium dioxide, the potassium salt is used as a mineralizer to promote the crystal form transformation of anatase-type to rutile-type TiO 2 and affect the crystal growth rate. If added first, it may preferentially participate in lattice adjustment at the high-temperature stage, but if other salts are added subsequently, it may interfere with its function; the phosphate salt is mainly used as a dispersant to inhibit particle agglomeration and adjust the pH value. Adding it prematurely may wrap the particle surface in advance and hinder the reaction of subsequent salts; adding it later may optimize the dispersibility; the aluminum salt is used for surface coating to improve weather resistance and dispersibility. Adding it first may form an aluminum hydroxide coating layer, hindering the penetration of other ions; adding it later is more likely to modify the surface charge. The time interval for adding the salt treatment agent is set to be 8 - 12 minutes, which is the most reasonable. Too long a time will affect the production output, and too short a time will result in uneven stirring of the added salts, affecting the product quality.

[0017] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0018] 1. The present invention optimizes the morphology of titanium dioxide particles by reducing the addition amount of salt treatment agents, so that the obtained titanium dioxide particles are spherical, thereby controlling the particle size distribution of calcined titanium dioxide, enhancing the hiding power of titanium dioxide, and reducing the amount of salt treatment agents used effectively reduces the production cost.

[0019] 2. The present invention further improves the quality of titanium dioxide by controlling the time intervals of various salt treatment agents. Specific Embodiments

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments.

[0021] Example 1

[0022] A method for producing high-hiding-power titanium dioxide at low cost. During the salt treatment process, the following salt treatment agents are sequentially added to the metatitanic acid slurry, and the time interval between the addition of adjacent two salt treatments is 10 minutes:

[0023] Based on the mass of K 2 O, the addition amount of potassium hydroxide is 0.19% of the mass of TiO 2 in the metatitanic acid slurry;

[0024] Based on the mass of P 2 O 5 the addition amount of phosphoric acid is 0.15% of the mass of TiO 2 in the metatitanic acid slurry;

[0025] Based on the mass of Al 2 O 3 the addition amount of aluminum sulfate is 0.26% of the mass of TiO 2 in the metatitanic acid slurry.

[0026] Example 2

[0027] A method for producing high-hiding-power titanium dioxide at low cost. During the salt treatment process, the following salt treatment agents are sequentially added to the metatitanic acid slurry, and the time interval between the addition of adjacent two salt treatments is 10 minutes:

[0028] Based on the mass of K 2 O, the addition amount of potassium hydroxide is 0.18% of the mass of TiO 2 in the metatitanic acid slurry;

[0029] Based on the mass of P 2 O 5 the addition amount of phosphoric acid is 0.15% of the mass of TiO 2 in the metatitanic acid slurry;

[0030] Using Al 2 O 3 as a mass meter, the addition amount of aluminum sulfate is 0.26% of the mass of TiO in the metatitanic acid slurry. 2

[0031] Example 3

[0032] A method for producing high hiding power titanium dioxide at low cost. During the salt treatment process, the following salt treatment agents are sequentially added to the metatitanic acid slurry, and the time interval between the addition of adjacent two salt treatments is 10 minutes:

[0033] Using K 2 O as a mass meter, the addition amount of potassium hydroxide is 0.2% of the mass of TiO in the metatitanic acid slurry; 2

[0034] Using P 2 O 5 as a mass meter, the addition amount of phosphoric acid is 0.15% of the mass of TiO in the metatitanic acid slurry; 2

[0035] Using Al 2 O 3 as a mass meter, the addition amount of aluminum sulfate is 0.26% of the mass of TiO in the metatitanic acid slurry. 2

[0036] Example 4

[0037] A method for producing high hiding power titanium dioxide at low cost. During the salt treatment process, the following salt treatment agents are sequentially added to the metatitanic acid slurry, and the time interval between the addition of adjacent two salt treatments is 10 minutes:

[0038] Using K 2 O as a mass meter, the addition amount of potassium hydroxide is 0.19% of the mass of TiO in the metatitanic acid slurry; 2

[0039] Using P 2 O 5 as a mass meter, the addition amount of phosphoric acid is 0.15% of the mass of TiO in the metatitanic acid slurry; 2

[0040] Using Al 2 O 3 as a mass meter, the addition amount of aluminum sulfate is 0.25% of the mass of TiO in the metatitanic acid slurry. 2

[0041] Example 5

[0042] ​​​​​​​A method for producing titanium dioxide with high hiding power at low cost. During the salt treatment process, the following salt treatment agents are sequentially added to the metatitanic acid slurry, and the time interval between the addition of adjacent two salt treatments is 10 minutes:

[0043] Calculated based on the mass of K 2 O, the addition amount of potassium hydroxide is 0.19% of the mass of TiO 2 in the metatitanic acid slurry;

[0044] Calculated based on the mass of P 2 O 5 the addition amount of phosphoric acid is 0.15% of the mass of TiO 2 in the metatitanic acid slurry;

[0045] Calculated based on the mass of Al 2 O 3 the addition amount of aluminum sulfate is 0.28% of the mass of TiO 2 in the metatitanic acid slurry.

[0046] Example 6

[0047] A method for producing titanium dioxide with high hiding power at low cost. During the salt treatment process, the following salt treatment agents are sequentially added to the metatitanic acid slurry, and the time interval between the addition of adjacent two salt treatments is 10 minutes:

[0048] Calculated based on the mass of K 2 O, the addition amount of potassium hydroxide is 0.19% of the mass of TiO 2 in the metatitanic acid slurry;

[0049] Calculated based on the mass of P 2 O 5 the addition amount of phosphoric acid is 0.15% of the mass of TiO 2 in the metatitanic acid slurry;

[0050] Calculated based on the mass of Al 2 O 3 the addition amount of aluminum sulfate is 0.3% of the mass of TiO 2 in the metatitanic acid slurry.

[0051] Example 7

[0052] A method for producing titanium dioxide with high hiding power at low cost. During the salt treatment process, the following salt treatment agents are sequentially added to the metatitanic acid slurry, and the time interval between the addition of adjacent two salt treatments is 8 minutes:

[0053] Calculated based on the mass of K 2 O, the addition amount of potassium hydroxide is 0.19% of the mass of TiO 2 in the metatitanic acid slurry;

[0054] Calculated based on the mass of P 2 O5 Mass meter, the addition amount of phosphoric acid is 0.15% of TiO in the metatitanic acid slurry; 2

[0055] By Al 2 O 3 Mass meter, the addition amount of aluminum sulfate is 0.26% of TiO in the metatitanic acid slurry; 2

[0056] Example 8

[0057] A method for producing titanium dioxide with high hiding power at low cost. During the salt treatment process, the following salt treatment agents are sequentially added to the metatitanic acid slurry, and the time interval between the addition of adjacent two salt treatments is 12 minutes:

[0058] By K 2 Mass meter, the addition amount of potassium hydroxide is 0.19% of TiO in the metatitanic acid slurry; 2

[0059] By P 2 O 5 Mass meter, the addition amount of phosphoric acid is 0.15% of TiO in the metatitanic acid slurry; 2

[0060] By Al 2 O 3 Mass meter, the addition amount of aluminum sulfate is 0.26% of TiO in the metatitanic acid slurry; 2

[0061] Comparative Example 1

[0062] This comparative example is basically the same as Example 1, the difference is:

[0063] By P 2 O 5 Mass meter, the addition amount of phosphate salt is 0.18% of TiO in the metatitanic acid slurry; 2

[0064] Comparative Example 2

[0065] This comparative example is basically the same as Example 1, the difference is:

[0066] By K 2 Mass meter, the addition amount of potassium hydroxide is 0.3% of TiO in the metatitanic acid slurry; 2

[0067] Comparative Example 3

[0068] This comparative example is basically the same as Example 1, the difference is:

[0069] By Al​​​​​​​2 O 3 Quality meter, the addition amount of aluminum sulfate is 0.36% of the mass of TiO in the metatitanic acid slurry. 2 by mass.

[0070] Comparative Example 4

[0071] This comparative example is basically the same as Example 1, the difference is that:

[0072] The addition order of the salt treatment agent is: phosphate salt, potassium salt, aluminum salt.

[0073] Comparative Example 5

[0074] This comparative example is basically the same as Example 1, the difference is that:

[0075] The addition order of the salt treatment agent is: aluminum salt, phosphate salt, potassium salt.

[0076] Comparative Example 6

[0077] This comparative example is basically the same as Example 1, the difference is that:

[0078] The three salt treatment agents are added simultaneously.

[0079] Comparative Example 7

[0080] This comparative example is basically the same as Example 1, the difference is that:

[0081] The time interval between the addition of adjacent two salt treatments is 5 minutes.

[0082] Comparative Example 8

[0083] This comparative example is basically the same as Example 1, the difference is that:

[0084] The time interval between the addition of adjacent two salt treatments is 20 minutes.

[0085] For the other processes of Examples 1-8 and Comparative Examples 1-8 that are not mentioned, they are the same as the existing process. The hiding power of the titanium dioxide obtained from Examples 1-8 and Comparative Examples 1-3 was detected, and the detection results are shown in Table 1:

[0086] Table 1

[0087]

[0088] From the perspective of cost, after reducing the dosage of the salt treatment agent, it can save 1.1 million yuan per year compared with CN106395893B when producing the same amount of titanium dioxide and the calcination temperature remains unchanged.

[0089] The above-described embodiments merely represent the specific implementation manners of the present application. The description thereof is relatively specific and detailed, but it should not be construed as a limitation to the protection scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the technical solution of the present application, several variations and improvements can still be made, and these all fall within the protection scope of the present application.

Claims

1. A method for producing high hiding power titanium dioxide at low cost, characterized in that: The amount of salt treatment agent added during the salt treatment of metatitanic acid slurry is: Calculated by the mass of P2O5, the amount of phosphate added is 0.15% of the mass of TiO2 in the metatitanic acid slurry; The amount of potassium salt added is 0.18-0.2% of the mass of TiO2 in the metatitanic acid slurry, calculated on the mass of K2O; Calculated by the mass of Al2O3, the amount of aluminum salt added is 0.25-0.3% of the mass of TiO2 in the titanate slurry.

2. The method for producing high hiding power titanium dioxide at low cost according to claim 1, characterized in that: The concentration of TiO2 in the titanic acid slurry is 40-370g / L.

3. The method for producing high hiding power titanium dioxide at low cost according to claim 1, characterized in that: The phosphate salt is phosphoric acid, the potassium salt is potassium hydroxide, and the aluminum salt is aluminum sulfate.

4. The method for producing high hiding power titanium dioxide at low cost according to claim 1, characterized in that: The amount of potassium salt added is 0.19% of the mass of TiO2 in the titanate slurry, calculated on the mass of K2O. The amount of aluminum salt added is 0.27% of the mass of TiO2 in the titanate slurry, calculated on the mass of Al2O3.

5. The method for producing high hiding power titanium dioxide at low cost according to claim 1, characterized in that: The order of adding phosphate salt, potassium salt and aluminum salt is potassium salt, phosphate salt, aluminum salt.

6. The method for producing high hiding power titanium dioxide at low cost according to claim 5, characterized in that: When adding phosphate, potassium and aluminum salts, different salt treatment agents are added at intervals of 8-12 minutes.

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