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CN-121974390-A - High-weather-resistance titanium dioxide prepared by chlorination process and preparation method

CN121974390ACN 121974390 ACN121974390 ACN 121974390ACN-121974390-A

Abstract

The application discloses high-weather-resistance titanium dioxide prepared by a chlorination method and a preparation method thereof, wherein the titanium dioxide comprises a titanium dioxide substrate and a coating layer positioned on the surface of the titanium dioxide, the coating layer at least comprises a compact silicon film layer, a zinc silicate film layer and a magnesium titanate film layer from inside to outside, the compact silicon film layer is formed by adding a soluble silicic acid source and a pH regulator into the chlorination method titanium dioxide substrate slurry for homogenization, and the pH value of the slurry is kept to be more than or equal to 10.0 in the preparation process of the chlorination method titanium dioxide substrate slurry. The titanium dioxide provided by the application has extremely high weather resistance, and can completely meet the use of scenes with high weather resistance requirements, such as outdoors.

Inventors

  • CHEN JIANLI
  • LIU XIAOJIE
  • WANG LIPING
  • HOU JIE
  • ZHOU WENJING
  • HU JIETAO
  • LIU SHUANG
  • GUO YONGYANG
  • CAO QINGXI
  • DU JINGWEI
  • LI RUIRUI
  • SHI WENCHEN
  • WANG YABO
  • GU JUNLING
  • ZHAI LELE
  • Zhao Yuang

Assignees

  • 河南佰利联新材料有限公司

Dates

Publication Date
20260505
Application Date
20251231

Claims (11)

  1. 1. The high weather-resistant titanium dioxide by using the chlorination process is characterized by comprising a titanium dioxide substrate and a coating layer positioned on the surface of the titanium dioxide, wherein the coating layer at least comprises a compact silicon film layer, a zinc silicate film layer and a magnesium titanate film layer from inside to outside; The compact silicon film layer is formed by adding a soluble silicic acid source and a pH regulator into the titanium dioxide substrate slurry of the chlorination process for homogenization, and the pH value of the slurry is kept to be more than or equal to 10.0 in the preparation process of the titanium dioxide substrate slurry of the chlorination process.
  2. 2. The high weather resistance titanium dioxide powder according to claim 1, The coating amount of the compact silicon film layer is 2-4% of the mass of the titanium dioxide base material in terms of silicon dioxide; preferably, the coating amount of the zinc silicate film layer is 2-4% of the mass of the titanium dioxide base material in terms of zinc oxide; Preferably, the coating amount of the magnesium titanate film layer is 0.5-2% of the mass of the titanium dioxide base material in terms of magnesium oxide.
  3. 3. The high weather resistance titanium dioxide powder according to claim 1, The compact silicon film layer is obtained through two-step deposition, wherein the first step is to firstly add part of the silicic acid source into titanium dioxide substrate slurry with the pH value more than or equal to 10.0, then slowly adjust the pH value to 9.0-9.7, and homogenize, and the second step is to continuously add the rest silicic acid source, then slowly adjust the pH value to 7.5-8.5, and homogenize to form the compact silicon film layer.
  4. 4. The high weather resistance titanium dioxide powder according to claim 1, The zinc silicate film layer is formed by the following steps: Adding a soluble silicic acid source, a soluble zinc source and a pH buffering agent into the slurry coated with the compact silicon film layer in parallel flow, and keeping the pH of the slurry at 8.0-10.0 to obtain a hydrated zinc silicate film layer; And after all the coating is finished, removing the moisture of the hydrated zinc silicate film layer through calcination to obtain the zinc silicate film layer.
  5. 5. The high weather resistance titanium dioxide powder according to claim 1, The magnesium titanate film layer is formed by the following steps: Adding a soluble titanium source, a soluble magnesium source and a pH buffering agent into the slurry coated with the compact silicon film layer and the hydrated zinc silicate film layer in parallel flow, and keeping the pH of the slurry at 8.0-10.0 to obtain an amorphous magnesium titanate precursor film layer; And after all the coating is finished, calcining to obtain the magnesium titanate film layer.
  6. 6. The high weather resistance titanium dioxide powder according to claim 1, The coating layer further comprises an aluminum oxide film layer positioned on the outer side of the magnesium titanate film layer; preferably, the coating amount of the alumina film layer is 1-3% of the mass of the titanium dioxide substrate.
  7. 7. A method for preparing the high weather resistance titanium dioxide according to any one of claims 1 to 6, which is characterized by comprising the following steps: S1, preparing titanium dioxide substrate slurry by a chlorination method, wherein the pH value of the slurry is kept to be more than or equal to 10.0 in the preparation process of the titanium dioxide substrate slurry by the chlorination method; s2, adding a soluble silicic acid source and a pH regulator into the titanium dioxide substrate slurry, and homogenizing to form a compact silicon film layer; s3, zinc silicate coating and magnesium titanate coating are carried out.
  8. 8. The method for preparing the high weather-resistant titanium dioxide by using the chlorination process as set forth in claim 7, wherein, The titanium dioxide substrate slurry prepared by the chloridizing method in the step S1 is prepared by the following steps: Adding water into a titanium dioxide base material of a chlorination method to prepare slurry before sanding, wherein the concentration of the slurry before sanding is 500-550 g/L calculated by titanium dioxide, and then mixing and sanding with a dispersing agent and a pH regulator to control the pH of the slurry to be more than or equal to 10; Preferably, the dispersing agent is at least one selected from the group consisting of sodium citrate, potassium citrate, sodium silicate, potassium silicate, sodium tripolyphosphate, sodium hexametaphosphate, sodium gluconate, sodium polyacrylate, and polycarboxylate.
  9. 9. The method for preparing the high weather-resistant titanium dioxide by using the chlorination process as set forth in claim 7, wherein, Step S2 further comprises: Firstly, adding part of the silicic acid source into titanium dioxide substrate slurry with the pH value of more than or equal to 10, wherein the adding amount of the part of the silicic acid source is 30-70% of the mass of all the silicic acid sources, then slowly adjusting the pH value to 9.0-9.7, and homogenizing; Continuously adding the rest silicic acid source, slowly adjusting the pH to 7.5-8.5, and homogenizing to form the compact silicon film layer; preferably, the zinc silicate coating film in step S3 further comprises: Adding a soluble silicic acid source, a soluble zinc source and a pH buffering agent into the slurry coated with the compact silicon film layer in parallel flow, and keeping the pH of the slurry at 8.0-10.0 to obtain a hydrated zinc silicate film layer; after all the coating is finished, removing the moisture of the hydrated zinc silicate film layer through calcination to obtain the zinc silicate film layer; preferably, the magnesium titanate coating in step S3 further comprises: adding a soluble titanium source, a soluble magnesium source and a pH buffering agent into the slurry coated with the compact silicon film layer and the hydrated zinc silicate film layer in parallel flow, and keeping the pH of the slurry at 8.0-10.0 to obtain an amorphous magnesium titanate precursor film layer; after all the coating is finished, calcining to obtain the magnesium titanate film layer; preferably, the pH buffer is NH 4 + /NH 3 buffer.
  10. 10. The method for preparing the high weather-resistant titanium dioxide by using the chlorination process as set forth in claim 7, wherein, Step S3 is followed by step S4: s4, adding a soluble aluminum source and a pH regulator in parallel flow, and keeping the pH value of the parallel flow at 7.0-8.0 to obtain the aluminum oxide film layer.
  11. 11. The method for preparing high weather resistance titanium dioxide according to claim 7, wherein the method further comprises: S1, taking titanium dioxide base materials of a chlorination method, adding water for pulping to obtain slurry before sanding, wherein the concentration of the slurry before sanding is 500-550 g/L calculated by titanium dioxide, then mixing with a dispersing agent and a pH regulator for sanding, controlling the pH of the slurry to be more than or equal to 10, adding alkaline water for dilution until the concentration of the slurry is 250-350 g/L calculated by titanium dioxide after sanding, and ensuring the pH of the slurry to be more than or equal to 10; s2, firstly adding part of the silicic acid source into titanium dioxide substrate slurry with the pH value of more than or equal to 10, wherein the adding amount of the part of the silicic acid source is 30-70% of the mass of all the silicic acid sources, then slowly adjusting the pH value to 9.0-9.7, and homogenizing; Continuously adding the rest silicic acid source, slowly adjusting the pH to 7.5-8.5, and homogenizing to form the compact silicon film layer; s3, adding a soluble silicic acid source, a soluble zinc source and a pH buffering agent in parallel, and keeping the pH of slurry at 8.0-10.0 to obtain a hydrated zinc silicate film layer; s4, adding a soluble titanium source, a soluble magnesium source and a pH buffering agent in parallel, and keeping the pH of the slurry at 8.0-10.0 to obtain an amorphous magnesium titanate precursor film layer; s5, adding a soluble aluminum source and a pH regulator in parallel flow, and keeping the pH value of the parallel flow at 7.0-8.0 to obtain an aluminum oxide film layer; S6, calcining to dehydrate the hydrated zinc silicate to obtain a zinc silicate film layer, and converting the amorphous magnesium titanate precursor film layer to generate a magnesium titanate film layer.

Description

High-weather-resistance titanium dioxide prepared by chlorination process and preparation method Technical Field The invention belongs to the technical field of titanium dioxide preparation, and particularly relates to high weather-resistant titanium dioxide prepared by a chlorination process and a preparation method. Background Titanium dioxide (TiO 2), commonly known as titanium dioxide, has excellent optical properties and stable chemical properties, is an important white pigment with the most wide application, and is known as monosodium glutamate in the white industry. The core value is extremely high refractive index, excellent hiding power, bright whiteness and good dispersibility. Titanium dioxide is widely applied to various fields such as paint (especially building exterior wall paint, automobile paint and industrial paint), plastics (outdoor products and building materials), printing ink, papermaking, chemical fiber, rubber, ceramics, cosmetics and the like. In many key application scenarios (especially outdoor), weather resistance becomes one of the most core performance indexes of titanium dioxide. Weather resistance refers to the ability of a pigment to resist long-term attack by natural environmental factors (mainly ultraviolet radiation, moisture, oxygen, temperature changes, atmospheric pollutants, etc.) while maintaining its color, luster, hiding power, and chalking degree. Titanium dioxide without surface treatment (called as a crude product or a base material) has some lattice defects, a plurality of photoactivation points exist on the surface of the titanium dioxide, the titanium dioxide has slight absorption to the visible ultraviolet spectrum, under the irradiation of water and other catalysts and long-term ultraviolet light, the titanium dioxide can generate continuous oxidation-reduction reaction to generate hydroxyl and peroxy hydroxyl free radicals, the hydroxyl and peroxy hydroxyl free radicals have high activity, can oxidize organic polymers in products, generate chain scission and degradation of high molecular chains, and destroy the continuity of the products, and can lead to chalking (surface loosening and powdery shedding), light loss (surface gloss reduction), discoloration/yellowing (yellowing or change of color) and cracking/peeling (seriously damage the structure of the coating or the material), thus not only seriously affecting the appearance and service life of the products, but also greatly reducing the protection function and value of the products. At present, the conventional method for improving the weather resistance of titanium dioxide mainly depends on coating a compact silicon film layer, but aluminum powder is required to be added in an oxidation section and reacts in a chlorine environment to generate AlCl 3 vapor, alCl 3 is taken as a crystal form conversion promoter and uniformly dispersed in TiCl 4 gas, and TiO 2 crystal nuclei are induced to directionally grow into a rutile structure at the high temperature of an oxidation furnace due to the special process of the titanium dioxide. And Al 2O3 microcrystalline nuclei are formed in the oxidation process, heterogeneous nucleation sites are provided, and particle agglomeration is avoided. The chloridizing process base stock is generally dry powder base stock obtained through an oxidation working section, wherein the Al 2O3 is about 0.8-1.5% of the TiO 2, so that the chloridizing process base stock has a higher isoelectric point (7.5-9.5). When the wet coating is adopted, the base material (containing adsorbed Cl 2/HCl) is firstly mixed with water for pulping, and the base material contains adsorbed Cl 2/HCl, so that the slurry is acidic (pH is usually 1-4), and the pH of the compact silicon coating is above 10, so that the slurry needs to cross isoelectric points in the coating process, the viscosity of the slurry can be increased, agglomeration is caused, coating is incomplete, weather resistance is reduced, and the conventional silicon-aluminum coating cannot meet the high weather resistance requirement which is required in the day-to-day. Therefore, it is necessary to develop a preparation method of high weather-resistant titanium dioxide by a chlorination process so as to solve the problems in the prior art. Disclosure of Invention The invention aims to provide high weather-resistant titanium dioxide prepared by a chlorination process and a preparation method thereof for solving the defects of the prior art. The invention aims at realizing the following technical scheme: The high weather-resistant titanium dioxide comprises a titanium dioxide substrate and a coating layer positioned on the surface of the titanium dioxide, wherein the coating layer at least comprises a compact silicon film layer, a zinc silicate film layer and a magnesium titanate film layer from inside to outside; The compact silicon film layer is formed by adding a soluble silicic acid source and a pH regulator into the titanium dioxide s