阅读说明：本技术 一种高耐光高遮盖造纸用钛白粉的制备方法 (Preparation method of high-light-resistance high-coverage titanium dioxide for papermaking ) 是由 陈建立 王莉萍 王永珊 周文静 李瑞瑞 冯亚阳 曹青喜 王欢欢 于 2019-04-30 设计创作，主要内容包括：本发明属于钛白粉制备技术领域,一种高耐光高遮盖造纸用钛白粉的制备方法,包括以下步骤：1)制备钛白粉料浆；2)将钛白粉料浆升温至60℃,加入铈盐溶液和TiOCl<Sub>2</Sub>溶液,同时加入磷酸盐溶液,然后均化；3)将步骤2)均化后料浆的pH值调节为2-4,再均化,同时加入FeSO<Sub>4</Sub>溶液和稀碱溶液,并维持料浆的pH值为2-4,然后均化；4)同时加入铝盐溶液和稀酸或稀碱溶液,包覆铝膜；5)包覆铝膜后的料浆经水洗、闪蒸、汽粉,得到钛白粉成品。采用本发明方法制得的造纸用钛白粉遮盖力、耐光性较优,且不影响最终产品的色相。(The invention belongs to the technical field of titanium dioxide preparation, and discloses a preparation method of high-light-resistance high-coverage titanium dioxide for papermaking, which comprises the following steps: 1) preparing titanium dioxide slurry; 2) heating the titanium dioxide slurry to 60 ℃, and adding cerium salt solution and TiOCl 2 Adding phosphate solution into the solution, and homogenizing; 3) adjusting the pH value of the homogenized slurry obtained in the step 2) to 2-4, and then homogenizing, and simultaneously adding FeSO 4 Solution and dilute alkali solution, and the pH value of the slurry is maintained to be 2-4, and then homogenization is carried out; 4) simultaneously adding an aluminum salt solution and a dilute acid or a dilute alkali solution to coat the aluminum film; 5) and washing the slurry coated with the aluminum film with water, flashing, and performing vapor powdering to obtain a titanium dioxide finished product. The titanium dioxide for papermaking prepared by the method has excellent covering power and light resistance, and does not influence the hue of the final product.)

1. The preparation method of the titanium dioxide for papermaking with high light resistance and high covering power is characterized by comprising the following steps:

1) preparing titanium dioxide slurry;

2) heating the titanium dioxide slurry to 60 ℃, and adding cerium salt solution and TiOCl₂Adding phosphate solution into the solution, and homogenizing;

3) adjusting the pH value of the homogenized slurry obtained in the step 2) to 2-4, and then homogenizing, and simultaneously adding FeSO₄Solution and dilute alkali solution, and the pH value of the slurry is maintained to be 2-4, and then homogenization is carried out;

4) simultaneously adding an aluminum salt solution and a dilute acid or a dilute alkali solution to coat the aluminum film;

5) and washing the slurry coated with the aluminum film with water, flashing, and performing vapor powdering to obtain a titanium dioxide finished product.

2. The method of claim 1, wherein: in step 1), TiO is used₂The concentration of the titanium dioxide slurry is 250-800 g/L.

3. The method of claim 1, wherein: the cerium salt solution is Ce (NH)₄)₂(NO₃)₆Solution or Ce (SO)₄)₂Solution of CeO₂The cerium salt accounts for TiO₂0.10-0.30wt% of the total amount.

4. The method of claim 1, wherein: with TiO₂Meter, TiOCl₂The addition amount of the titanium pigment accounts for TiO in the titanium pigment slurry₂0.15-0.60wt% of the total amount.

5. The production method according to any one of claims 1 to 4, characterized in that: the phosphate solution is Na₂HPO₄Solution, NaH₂PO₄Solution and Na₃PO₄One or more of the solutions as P₂O₅The amount of phosphate added is calculated according to the amount of TiO₂2-4wt% of the total amount.

6. The method of claim 1, wherein: in step 3), dilute H is used₂SO₄Adjusting the pH value of the homogenized slurry in the step 2) to 2-4, and homogenizing for 20 min; the FeSO₄The concentration of the solution is 80-200g/L, and Fe is used₂O₃The addition amount of the catalyst is calculated according to the TiO₂Adding for 45min, and homogenizing for 30min, wherein the total amount is 1-3 wt%.

7. The method of claim 1, wherein: in the step 4), dilute alkali is used for adjusting the pH value of the slurry to 8.0-9.0, the adjustment is carried out for 30min, and the homogenization is carried out for 30 min; adding NaAlO at the same time ₂Solution and dilute acid solution or Al₂(SO₄)₃Keeping pH value of the solution and dilute alkali solution at 8.0-9.0, adding for 90min, and homogenizing for 30 min.

8. The method of claim 7, wherein: with Al₂O₃Meter, the NaAlO₂The concentration of the solution is 80-200g/L, and the Al is₂(SO₄)₃The concentration of the solution is 80-200g/L, NaAlO₂Or Al₂(SO₄)₃In an amount of TiO₂1-3wt% of the total amount.

9. The method according to claim 1, wherein the reaction mixture is heated to a temperature in the reaction mixtureThe method comprises the following steps: in step 5), before washing with water, dilute H is used₂SO₄Adjusting pH to 6, adjusting for 30min, and homogenizing for 120 min.

Technical Field

The invention belongs to the technical field of titanium dioxide preparation, and particularly relates to a preparation method of high-light-resistance high-coverage titanium dioxide for papermaking.

Background

Titanium dioxide is a very important white pigment and is widely applied to the industries of paint, plastics, papermaking, printing ink and the like. Paper making is the third largest user of titanium dioxide. Titanium dioxide is used as a paper filler and is mainly used in high-grade paper and thin paper. The titanium dioxide is added into the paper, so that the paper has better whiteness, good gloss, high strength, thinness, smoothness, no penetration during printing and light weight. However, the manufacturing process is the same for any kind of paper, and the main reason for determining which kind of titanium white is selected by the paper mill is the cost of paper making. Because the cost proportion of the titanium white in the paper making is as high as 30% -50%, the selection of the titanium white can be considered as a weight comparison under the condition that a paper mill meets the requirements of users.

For titanium dioxide, the key indexes are the light resistance and the covering power of the titanium dioxide in paper. In the prior art, two methods are generally used for improving the light resistance, namely, a titanium salt or a cerium salt is added respectively, and both can achieve better light resistance; titanium salt (chlorination by-product TiOCl) is added₂) The volatility is strong, the coating technology difficulty is high, the light resistance is good when the cerium salt is added, but the cost is high, and the color phase of the final product can be influenced after the cerium salt is yellow.

Disclosure of Invention

Aiming at the situation, the invention aims to provide a preparation method of titanium dioxide for papermaking with high light resistance and high covering power₂O₃The film layer is helpful for increasing scattering centers, and the ferric oxide has space separation effect and reduces TiO₂Agglomeration of the particles to make more TiO₂The particles get intoAnd the action of light scattering center is irradiated, so that the covering power of the titanium dioxide is improved.

The invention provides a preparation method of high-light-resistance high-coverage titanium dioxide for papermaking, which comprises the following steps:

1) Preparing titanium dioxide slurry;

2) heating the titanium dioxide slurry to 60 ℃, and adding cerium salt solution and TiOCl₂Adding phosphate solution into the solution, and homogenizing;

3) adjusting the pH value of the homogenized slurry obtained in the step 2) to 2-4, and then homogenizing, and simultaneously adding FeSO₄Solution and dilute alkali solution, and the pH value of the slurry is maintained to be 2-4, and then homogenization is carried out;

4) simultaneously adding an aluminum salt solution and a dilute acid or a dilute alkali solution to coat the aluminum film;

5) and washing the slurry coated with the aluminum film with water, flashing, and performing vapor powdering to obtain a titanium dioxide finished product.

Preferably, in step 1), TiO is used₂The concentration of the titanium dioxide slurry is 250-800 g/L.

In the present invention, the titanium dioxide slurry is prepared from a sand mill obtained by sand milling a titanium dioxide base material, and the particle size of the sand mill can be selected according to the requirement, for example, the particle size can be 0.30-0.40 μm (obtained by Malvern 3000 test).

Preferably, the cerium salt solution is Ce (NH)₄)₂(NO₃)₆Solution or Ce (SO)₄)₂Solution of CeO₂The cerium salt accounts for TiO₂0.10-0.30wt% of the total amount.

Preferably, in TiO₂Meter, TiOCl₂The addition amount of the titanium pigment accounts for TiO in the titanium pigment slurry₂0.15-0.60wt% of the total amount.

In the present invention, the cerium salt solution and TiOCl₂The adding time of the solution is 30-60min,

Preferably, the phosphate solution is Na₂HPO₄Solution, NaH₂PO₄Solution and Na₃PO₄One or more of the solutions as P₂O₅The amount of phosphate added is calculated according to the amount of TiO₂Adding phosphate solution 2-4wt%, and homogenizing for 60 min.

According to the invention, in step 3), dilute H is used₂SO₄Adjusting the pH value of the homogenized slurry in the step 2) to 2-4, and homogenizing for 20 min.

Preferably, the FeSO₄The concentration of the solution is 80-200g/L, and Fe is used₂O₃The addition amount of the catalyst is calculated according to the TiO₂Adding for 45min, and homogenizing for 30min, wherein the total amount is 1-3 wt%.

Preferably, in the step 4), dilute alkali is used for adjusting the pH value of the slurry to 8.0-9.0, the adjustment is carried out for 30min, and the homogenization is carried out for 30 min; adding NaAlO at the same time₂Solution and dilute acid solution or Al₂(SO₄)₃Keeping pH value of the solution and dilute alkali solution at 8.0-9.0, adding for 90min, and homogenizing for 30 min.

Further preferably, Al₂O₃Meter, the NaAlO₂The concentration of the solution is 80-200g/L, and the Al is₂(SO₄)₃The concentration of the solution is 80-200g/L, NaAlO₂Or Al₂(SO₄)₃In an amount of TiO₂1-3wt% (in terms of Al) of the total amount₂O₃Meter).

The dilute acid in the invention is dilute H₂SO₄The solution is NaOH solution or KOH solution.

According to the invention, in step 5), before washing with water, dilute H is used₂SO₄Adjusting pH to 6, adjusting for 30min, and homogenizing for 120 min.

The processes not limited in the present invention are performed by conventional methods in the art, such as water washing, flash evaporation, vapor powder, etc.

Compared with the prior art, the preparation method of the titanium dioxide has the following beneficial effects:

1. according to the invention, the mixed film of titanium phosphate and cerium phosphate is prepared by doping cerium salt and titanium salt, so that the light resistance of the titanium dioxide is improved, and the hue is not influenced; then coating a layer of Fe on the surface of the titanium dioxide₂O₃A film layer for increasing scattering center and iron oxideHas steric separation effect and reduces TiO₂Agglomeration of the particles to make more TiO₂The particles play a role of incident light scattering centers, so that the covering power of the titanium dioxide is improved.

2. The method adopts the titanium oxychloride of the partial chlorination process waste byproduct as the titanium source, so that the light resistance of the titanium dioxide can be improved, the waste byproduct can be reused, and the cyclic utilization of resources is promoted.

3. The invention adopts the byproduct FeSO of the sulfuric acid method titanium dioxide process₄·7H₂And O is used as an iron source, so that the covering power of the product can be improved, the waste and the side products are recycled, and the cyclic continuous development of the sulfuric acid method chlorination method double processes is promoted.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the following embodiments of the present invention, and it should be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.