阅读说明：本技术 高水分散性钛白浆的制备方法 (Preparation method of high-water-dispersibility titanium dioxide slurry ) 是由 刘琦 淦文军 袁立军 罗静 徐庭敏 于 2021-10-22 设计创作，主要内容包括：本发明公开了一种高水分散性钛白浆的制备方法,属于钛白生产领域。高水分散性钛白浆的制备方法包括如下步骤：a.将砂磨后的浆料过筛；b.加入分散剂搅拌分散；c.升温加入硅酸盐溶液,并流加入铝盐溶液；d.降温加入稀酸溶液、磷酸盐溶液、铝盐溶液；e.加入铝盐溶液调节pH得到高水分散性钛白浆。本发明可以明显提高钛白浆料的水分散性和流动性,本发明的制备发明简单,生产成本低,制得的钛白浆可直接以钛白浆的形式用于造纸体系,可有效解决现有钛白浆水分散性较低的问题。(The invention discloses a preparation method of high-water-dispersibility titanium dioxide slurry, belonging to the field of titanium dioxide production. The preparation method of the high-water-dispersibility titanium dioxide slurry comprises the following steps: a. sieving the sanded slurry; b. adding a dispersing agent, stirring and dispersing; c. heating, adding silicate solution, and adding aluminum salt solution in parallel; d. cooling and adding dilute acid solution, phosphate solution and aluminum salt solution; e. adding an aluminum salt solution to adjust the pH value to obtain the high-water-dispersibility titanium white slurry. The invention can obviously improve the water dispersibility and the fluidity of the titanium white slurry, the preparation method of the invention is simple, the production cost is low, the prepared titanium white slurry can be directly used for a papermaking system in the form of the titanium white slurry, and the problem of lower water dispersibility of the existing titanium white slurry can be effectively solved.)

1. The preparation method of the high-water-dispersibility titanium dioxide slurry is characterized by comprising the following steps of:

a. sieving the slurry after sanding, and controlling TiO in the slurry after sieving₂The concentration of (b) is 400-550 g/L;

b. b, adding a dispersing agent into the slurry treated in the step a, and stirring and dispersing for 30-60 min;

c. b, heating the slurry treated in the step b to 70-100 ℃, then adding a silicate solution, adding an aluminum salt solution in parallel to adjust the pH value to 9-10, and curing for 60-120 min;

d. c, cooling the slurry treated in the step c to 30-70 ℃, adding a dilute acid solution to adjust the pH value to 3-6, curing for 30-45min, then adding a phosphate solution, adding an aluminum salt solution in parallel to adjust the pH value to 4-7, and curing for 90-120 min;

e. and d, adding the aluminum salt solution into the slurry treated in the step d, adjusting the pH to 5-8 by using a pH regulator, and curing for 90-180min to obtain the high-water-dispersibility titanium white slurry.

2. The method for preparing high-water-dispersibility titanium white slurry according to claim 1, characterized in that: in the step a, the mesh number of the screened mesh is 500 meshes, and the temperature of the screened slurry is controlled to be 30-70 ℃.

3. The method for preparing high-water-dispersibility titanium white slurry according to claim 1, characterized in that: in the step b, the dispersant comprises nitrate, and the addition amount of the nitrate is TiO in the slurry₂0.2-0.4% of the total amount.

4. The method for preparing high-water-dispersibility titanium white slurry according to claim 3, characterized in that: the dispersing agent also comprises at least one of polycarboxylate, phosphate salt, amide salt and stearate, and the adding amount of the dispersing agent is TiO in the slurry₂0.2-0.6% of the total amount.

5. The method for preparing high-water-dispersibility titanium white slurry according to claim 1, characterized in that: in the step c, the concentration of the silicate is 50-150g/L and SiO is used₂The addition amount is calculated as TiO in the slurry₂1-5% of the total amount.

6. The method for preparing high-water-dispersibility titanium white slurry according to claim 1, characterized in that: in the step c, the aluminum salt solution is an acidic aluminum salt solution, and the concentration is 50-150 g/L.

7. The method for preparing high-water-dispersibility titanium white slurry according to claim 1, characterized in that: in the step d, the phosphate is at least one of sodium phosphate, sodium monohydrogen phosphate, sodium dihydrogen phosphate and phosphoric acid, the concentration of the phosphate is 30-150g/L, and P is used₂O₅The addition amount of the TiO in the slurry is counted₂0.5-3% of the total amount.

8. The method for preparing high-water-dispersibility titanium white slurry according to claim 1, characterized in that: in the step d, the aluminum salt solution is an acidic aluminum salt solution or a basic aluminum salt solution, and the concentration is 50-150 g/L.

9. The method for producing a high-water-dispersibility titanium white slurry according to claim 1The preparation method is characterized by comprising the following steps: in step e, the aluminum salt solution is acidic aluminum salt solution or alkaline aluminum salt solution, the concentration is 50-150g/L, and Al is used₂O₃The addition amount of the TiO in the slurry is counted₂1-6% of the total amount.

10. The method for preparing high-water-dispersibility titanium white slurry according to claim 1, characterized in that: in the step e, the pH regulator is dilute acid or dilute alkali.

Technical Field

The invention belongs to the field of titanium dioxide production, relates to a preparation method of titanium dioxide slurry, and particularly relates to a preparation method of high-water-dispersibility titanium dioxide slurry.

Background

The production field of decorative paper has high requirements on the performance of titanium dioxide, so that the titanium dioxide needs to be subjected to surface treatment, one or more film layers are densely coated on the surface of the titanium dioxide to isolate direct irradiation of ultraviolet light on the surface of the titanium dioxide, the photochemical activity of the titanium dioxide is effectively delayed, the light resistance of the titanium dioxide is remarkably increased, and the performances such as covering power, whiteness and the like of the titanium dioxide are ensured so as to achieve excellent application performance in the decorative paper.

Modern paper making process includes diluting paper pulp suitable for paper quality with water to certain concentration, dewatering in the wire of paper making machine to form wet paper sheet, squeezing to dewater and stoving to produce paper. Therefore, the titanium dioxide is required to be well mixed with the paper pulp, and the titanium dioxide is required to have good water dispersibility while ensuring good covering power, whiteness and light fastness. The titanium white pigment has the defects of high surface hydroxyl content, strong hydrophilicity, high density and the like, so the titanium white slurry is very easy to have a sedimentation phenomenon in the long-term storage process. The surface of the titanium white needs to be modified so as to achieve the aim of preparing the titanium white slurry with high water dispersibility.

7/18/2012 CN102585559A discloses a preparation method of a high-light-resistance titanium dioxide pigment, which adopts a silicon-phosphorus-aluminum coating, and the Si content of the coating is Si₂0.5-4% of O, 1-5% of P-containing amount (P2O 5), and Al-containing amount (Al)₂O₃Calculated as 1 to 8 percent, and is coated on the surface of the titanium dioxide particles in the form of silicon dioxide and aluminum phosphate.

10.10/10/2012 CN101857736A discloses a production method of high-light-resistance rutile titanium dioxide, which adopts a zirconium-phosphorus-aluminum coating, wherein the Zr content is 0.2-2 percent calculated by ZrO, and the P content is P₂O₅Calculated as 0.2-4%, and the amount of Al contained is Al₂O₃Calculated as 0.6 to 4.7 percent, and is coated on the surface of the titanium dioxide particles in the forms of zirconium phosphate, aluminum phosphate and hydrated alumina.

Year 2013, month 5 and day 22CN103113762A discloses a preparation method of high-light-resistance decorative laminated paper titanium dioxide, which adopts a phosphor-aluminum coating, and the amount of P is P₂O₅Calculated as 1-5 percent, and the amount of Al contained is Al₂O₃3 to 10 percent of the total weight of the composite material, and adopts a mode of repeatedly coating aluminum, wherein one layer and three layers are hydrated aluminum oxide, and the other layer is aluminum phosphate and is coated on the surface of titanium dioxide particles, belonging to heavy aluminum-coated light phosphorus coating.

Disclosure of Invention

The invention aims to solve the technical problem of low water dispersibility of the existing titanium white slurry.

The technical scheme adopted by the invention for solving the technical problems is as follows: the preparation method of the high-water-dispersibility titanium dioxide slurry comprises the following steps:

a. sieving the slurry after sanding, and controlling TiO in the slurry after sieving₂The concentration of (b) is 400-550 g/L;

b. adding a dispersing agent into the slurry treated in the step a, and stirring for 30-60 min;

c. b, heating the slurry treated in the step b to 70-100 ℃, then adding a silicate solution, adding an aluminum salt solution in parallel to adjust the pH value to 9-10, and curing for 60-120 min;

d. c, cooling the slurry treated in the step c to 30-70 ℃, adding a dilute acid solution to adjust the pH value to 3-6, curing for 30-45min, then adding a phosphate solution, adding an aluminum salt solution in parallel to adjust the pH value to 4-7, and curing for 90-120 min;

e. and d, adding the aluminum salt solution into the slurry treated in the step d, adjusting the pH to 5-8 by using a pH regulator, and curing for 90-180min to obtain the high-water-dispersibility titanium white slurry.

In the step a, the mesh number of the screened mesh is 500 meshes, and the temperature of the screened slurry is controlled to be 30-70 ℃.

In the step b, the dispersant comprises nitrate, and the addition amount of the nitrate is TiO in the slurry₂0.2-0.4% of the total amount.

Further, the dispersant also comprises at least one of polycarboxylate, phosphate ester salt, amide salt and stearate, and the addition amount of the dispersant is TiO in the slurry₂0.2-0.6% of the total amount.

Furthermore, the adding time of the dispersing agent is controlled to be 10min-30 min.

In the step c, the concentration of the silicate is 50-150g/L and SiO is used₂The addition amount is calculated as TiO in the slurry₂1-5% of the total amount.

Further, the silicate is sodium silicate, potassium silicate, or the like.

In the step c, the aluminum salt solution is an acidic aluminum salt solution, and the concentration is 50-150 g/L.

Further, the adding time of the silicate and the aluminum salt in the step c is controlled to be 60-120 min.

In the step d, the phosphate is at least one of sodium phosphate, sodium monohydrogen phosphate, sodium dihydrogen phosphate and phosphoric acid, the concentration of the phosphate is 30-150g/L, and P is used₂O₅The addition amount of the TiO in the slurry is counted₂0.5-3% of the total amount.

In the step d, the aluminum salt solution is an acidic aluminum salt solution or a basic aluminum salt solution, and the concentration is 50-150 g/L.

Further, the adding time of the phosphate and the aluminum salt in the step d is controlled to be 30-60 min.

In the step e, the aluminum salt solution is an acidic aluminum salt solution or a basic aluminum salt solution, the concentration is 50-150g/L, and Al is used₂O₃The addition amount of the TiO in the slurry is counted₂1-6% of the total amount.

Further, the adding time of the aluminum salt in the step e is controlled to be 60-90 min.

In the step e, the pH regulator is dilute acid or dilute alkali.

Further, the dilute acid is hydrochloric acid, sulfuric acid, etc., and the dilute alkali is sodium hydroxide, potassium hydroxide, etc.

The invention has the beneficial effects that: the invention adopts a small amount of dispersant to increase the dispersibility and stability of the titanium dioxide in a water-based system; the phosphate can better isolate the migration of ultraviolet light to electrons in titanium dioxide particles, and the photochemical activity of the titanium dioxide is effectively reduced; the titanium white slurry can be better coated with silicon and phosphorus by controlling the pH value and the curing time, and the fluidity of the titanium white slurry is obviously improved by the coating layer.

At present, no titanium white slurry in the market is directly applied to the papermaking industry, the titanium white slurry prepared by the method can be directly applied to a papermaking system, and a new application method of titanium white pigment is added. Meanwhile, the preparation method can save the subsequent procedures of flash drying, gas powder, packaging and the like for manufacturers producing titanium white, thereby saving a large amount of labor and material cost; for papermaking customers, the titanium white pulp can be better mixed with paper pulp, and has the advantages of convenient use, no dust pollution, better particle size control, less coarse particles, low price and the like.

Detailed Description

The technical solution of the present invention can be specifically implemented as follows.

The preparation method of the high-water-dispersibility titanium dioxide slurry comprises the following steps:

a. sieving the slurry after sanding, and controlling TiO in the slurry after sieving₂The concentration of (b) is 400-550 g/L;

b. adding a dispersing agent into the slurry treated in the step a, and stirring for 30-60 min;

c. b, heating the slurry treated in the step b to 70-100 ℃, then adding a silicate solution, adding an aluminum salt solution in parallel to adjust the pH value to 9-10, and curing for 60-120 min;

d. c, cooling the slurry treated in the step c to 30-70 ℃, adding a dilute acid solution to adjust the pH value to 3-6, curing for 30-45min, then adding a phosphate solution, adding an aluminum salt solution in parallel to adjust the pH value to 4-7, and curing for 90-120 min;

e. and d, adding the aluminum salt solution into the slurry treated in the step d, adjusting the pH to 5-8 by using a pH regulator, and curing for 90-180min to obtain the high-water-dispersibility titanium white slurry.

For better experimental purposes, it is therefore preferred that in step a, the mesh number of the screen is 500, and the temperature of the slurry after screening is controlled to be 30-70 ℃.

In order to increase the dispersibility and stability of titanium dioxide in the aqueous system, it is therefore preferable that in step b above, the dispersant comprises nitrate in an amount of TiO in the slurry₂0.2-0.4% of the total amount; more preferably, the aboveThe dispersing agent also comprises at least one of polycarboxylate, phosphate salt, amide salt and stearate, and the adding amount of the dispersing agent is TiO in the slurry₂0.3-0.6% of the total amount, and in order to ensure that the reaction is more complete, the adding time of the dispersing agent is controlled to be 10-30 min.

For better coating titanium dioxide, therefore, in the step c, the concentration of the silicate is preferably 50-150g/L, and SiO is used₂The addition amount is calculated as TiO in the slurry₂1-5% of the total amount, wherein the silicate is sodium silicate, potassium silicate and the like; the aluminum salt solution is acidic aluminum salt solution, the concentration is 50-150g/L, and the adding time of silicate and aluminum salt in the step c is controlled to be 60-120 min.

For better coating titanium dioxide, it is preferable that in the step d, the phosphate is at least one of sodium phosphate, sodium monohydrogen phosphate, sodium dihydrogen phosphate and phosphoric acid, the concentration of the phosphate is 30-150g/L, and P is used₂O₅The addition amount of the TiO in the slurry is counted₂0.5-3% of the total amount, wherein the aluminum salt solution is an acidic aluminum salt solution or a basic aluminum salt solution, the concentration is 50-150g/L, and the adding time of the phosphate and the aluminum salt in the step d is controlled to be 30-60 min.

For better coating titanium dioxide, it is preferable that in step e, the aluminum salt solution is an acidic aluminum salt solution or a basic aluminum salt solution, the concentration is 50-150g/L, and Al is used₂O₃The addition amount of the TiO in the slurry is counted₂1-6% of the total amount, and the adding time of the aluminum salt in the step e is controlled to be 60-90 min; more preferably, the pH regulator is a dilute acid or a dilute alkali, the dilute acid is hydrochloric acid, sulfuric acid, or the like, and the dilute alkali is sodium hydroxide, potassium hydroxide, or the like.

The technical solution and effects of the present invention will be further described below by way of practical examples.

Examples

The present invention provides 3 groups of examples for preparing high water dispersibility titanium white slurry by the preparation method of the present invention.

Example 1 the specific experimental procedure was as follows:

a. after sanding, the slurry passes through a 500-mesh screen to obtain slurry to be used, the concentration of the titanium dioxide slurry is 450g/L, the temperature is raised to 55 ℃, and the initial pH value is 10.1;

b.10min later, a mixture of 0.3% potassium nitrate and 0.2% sodium polycarboxylate (in the form of TiO)₂Gross amount), stirring and dispersing for 30 min;

c. heating to 80 deg.C, and adding 2.5% sodium silicate (TiO) within 60min₂Gross amount), adding aluminum sulfate, maintaining pH value at 9-10, aging for 60 min;

d. adding water, cooling to 55 deg.C, adding dilute sulfuric acid, maintaining pH at 4.5-5.5, aging for 30min, and adding 1.5% mixed solution of phosphoric acid and sodium dihydrogen phosphate (TiO) within 45min₂Gross amount), adding sodium metaaluminate in parallel, maintaining pH value at 5.0-6.0, and aging for 90 min.

e. Keeping the temperature constant, adding 4.0% aluminum sulfate solution (in TiO) for 60min₂Gross amount), adding sodium hydroxide solution to maintain the pH value between 6.0 and 6.5, curing for 120min, and obtaining the high-water-dispersibility titanium white slurry after the curing is finished.

Example 2 the specific experimental procedure was as follows:

a. after sanding, the slurry passes through a 500-mesh screen to obtain slurry to be used, the concentration of the titanium dioxide slurry is 500g/L, the temperature is raised to 50 ℃, and the initial pH is 10.5;

b.10min later, a mixture of 0.2% potassium nitrate and 0.25% sodium stearate (in the form of TiO)₂Gross amount), stirring and dispersing for 30 min;

c. heating to 85 deg.C, and adding 3.0% sodium silicate (TiO) within 90min₂Gross amount), adding aluminum sulfate, maintaining pH value at 9-10, aging for 90 min;

d. adding water, cooling to 50 deg.C, adding dilute sulfuric acid, maintaining pH at 5.0-5.5, aging for 30min, and adding 2.0% sodium phosphate (made of TiO) within 60min₂Gross amount), adding sodium metaaluminate at the same time, maintaining pH value between 5.0-5.5, and aging for 100 min.

e. Keeping the temperature constant, adding 4.5% aluminum sulfate solution (in TiO) for 90min₂Gross amount), adding sodium hydroxide solution to maintain the pH value between 6.0 and 6.5, curing for 150min, and obtaining the high-water-dispersibility titanium white slurry after the curing is finished.

Example 3 the specific experimental procedure was as follows:

a. after sanding, the slurry passes through a 500-mesh screen to obtain slurry to be used, the concentration of the titanium dioxide slurry is 500g/L, the temperature is raised to 55 ℃, and the initial pH value is 10.8;

b.10min adding 0.3% potassium nitrate and 0.35% mixed solution of sodium polycarboxylate and sodium stearate (made of TiO)₂Gross amount), stirring and dispersing for 45 min;

c. heating to 85 deg.C, and adding 2.5% sodium silicate (TiO) within 60min₂Gross amount), adding aluminum sulfate, maintaining pH value at 9-10, aging for 60 min;

d. adding water, cooling to 55 deg.C, adding dilute sulfuric acid, maintaining pH at 5.0-6.0, aging for 30min, and adding 2.0% mixed solution of sodium phosphate and sodium dihydrogen phosphate (TiO) within 45min₂Gross amount), adding aluminum sulfate in parallel, maintaining pH value between 5.5-6.5, and aging for 90 min.

e. Keeping the temperature constant, adding 4.0% sodium metaaluminate solution (in TiO) for 60min₂Gross amount), adding dilute sulphuric acid solution to maintain the pH value between 6.5 and 7.0, curing for 120min, and obtaining the high-water-dispersibility titanium white slurry after the curing is finished.

The high water dispersibility titanium white slurries prepared in examples 1 to 3 were tested by pouring the slurries prepared in examples 1 to 3 into a 100ml graduated cylinder with a mill, sealing and placing in a constant temperature oven, and recording the height of the slurries at intervals. To ensure the reliability of the results, three replicates of each example sample were performed, the results of which are shown in table 1:

table 1 example settling height (i.e. water dispersion stability) data at different times

The invention adopts the commercially available domestic and foreign papermaking titanium dioxide in the existing market as the comparative examples 1-3 (the comparative examples 1-3 are the purchased titanium dioxide which is currently used in the papermaking system in the market), and the application detection of the melamine resin system is carried out on the examples 1-3 and the comparative examples 1-3, and the results are shown in the table 2:

TABLE 2 comparison of examples with papermaking titanium dioxide application data at home and abroad

From the test data in tables 1 and 2, it can be seen that: the titanium white slurry prepared by the method has high water dispersion and good stability, does not have the problem of deposition in the subsequent use process, and can be used in the papermaking production process. The application performance of the embodiments 1, 2 and 3 is superior to that of the domestic titanium white 1 and 2 and is close to the best level of the current similar products, and the titanium white pulp prepared by the method has better indexes, and can be well used in a decorative laminated paper system.