Preparation method of titanium dioxide for chemical fiber

Abstract

The application discloses a preparation method of titanium white powder for chemical fibers, and comprises the following steps: S1, preparing a titanium dioxide base material slurry: taking titanium white base material, adding an organic dispersing agent, and preparing a titanium dioxide base material slurry; S2, coating: taking the titanium dioxide base material slurry, and sequentially performing zirconium silicate coating and trihydroxy aluminum stone coating; S3, steam powdering: taking the coated material, adding a titanate additive for steam powdering, and obtaining titanium white powder. The application improves the compatibility with spinning raw materials by using an organic dispersing agent in the coating and slurry preparation process, and then improves the weather resistance of the titanium white powder by zirconium silicate coating, and further improves the water dispersibility of the titanium white powder by the condensation of trihydroxy aluminum stone coating and the titanate additive, so that the extinction effect and weather resistance of the chemical fibers are improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of titanium dioxide preparation, and particularly relates to a preparation method of titanium dioxide for chemical fibers. BACKGROUND

[0002] Titanium dioxide is an important inorganic chemical pigment, and the main component is titanium dioxide. Titanium dioxide is a good chemical fiber matting additive in the market in terms of hiding power, whiteness and other comprehensive performance. When the particle size of titanium dioxide is about half of the wavelength of visible light (i.e. the particle size distribution is about half of the wavelength range of light), the matting effect is best (at this time, the scattering and diffraction performance is basically balanced).

[0003] The conventional titanium dioxide for chemical fibers is generally anatase type. Compared with rutile titanium dioxide, the anatase titanium dioxide is softer and will not damage the spinneret. The rutile titanium dioxide has relatively high particle hardness, and if there are large particles or poor sphericity of particle morphology, the service life of the spinneret will be affected. However, the particle size of the anatase titanium dioxide produced industrially is large, and the best matting effect cannot be achieved. Moreover, the anatase titanium dioxide has photocatalytic activity, which will degrade the aging problem of the fiber, and needs to be coated and modified to obtain a more stable product with better dispersibility. If the ultrafine titanium dioxide powder is directly used, it is easy to agglomerate (even to block the spinneret), and the spinnability is poor. At the same time, the direct use of titanium dioxide is easy to cause photocatalysis.

[0004] In addition, the wet dispersion of the titanium dioxide is difficult at present, and has the characteristics of easy settlement and agglomeration, which limits the application of the titanium dioxide. In the process of manufacturing chemical fibers, due to the low water dispersibility of the titanium dioxide, the matting effect and weather resistance of the chemical fibers are difficult to improve. Therefore, the application provides a titanium dioxide for chemical fibers with good water dispersibility and a preparation method thereof. SUMMARY

[0005] The purpose of the application is to solve the problems in the prior art and provide a preparation method of titanium dioxide for chemical fibers.

[0006] The purpose of the application is achieved by the following technical scheme:

[0007] A preparation method of titanium dioxide for chemical fibers, comprising the following steps:

[0008] S1. Preparing a titanium dioxide-based material slurry: taking a titanium dioxide base material, adding an organic dispersant, and preparing a titanium dioxide-based material slurry;

[0009] S2. Coating: taking the titanium dioxide-based material slurry, and sequentially coating with zirconium silicate and aluminum trihydroxide;

[0010] S3. Steam powdering: taking the coated material, adding a titanate additive for steam powdering, and obtaining titanium dioxide.

[0011] Preferably, the titanium dioxide base material in step S1 is rutile titanium dioxide; the organic dispersing agent is monoisopropanolamine, and the addition amount is 0.05-0.1% of the mass of the titanium dioxide base material.

[0012] Preferably, after adding the organic dispersing agent in step S1, the titanium dioxide base material slurry is obtained by beating, grinding and grading, and the average particle size is ≤0.305 μm.

[0013] Preferably, the zirconium silicate coating in step S2 further comprises the following steps:

[0014] The pH of the titanium dioxide base material slurry is adjusted to 9.5-10, a silicon source and a zirconium source are added, and a zirconium silicate coating layer is obtained after maturation.

[0015] Preferably, the silicon source and the zirconium source are used in an amount of 0.6-0.8% and 0.4-0.6% of the mass of the titanium dioxide base material, respectively, in terms of SiO2 and ZrO2.

[0016] Preferably, the aluminum trihydroxide coating in step S2 further comprises the following steps:

[0017] The pH of the titanium dioxide base material slurry coated with the zirconium silicate coating layer is adjusted to 10.0-10.5, an aluminum source and a pH adjuster are added in parallel flow, the parallel flow pH is maintained at 10.0-10.5, and an aluminum trihydroxide coating layer is obtained after maturation.

[0018] Preferably, the aluminum source is used in an amount of 2-3% of the mass of the titanium dioxide base material in terms of Al2O3.

[0019] Preferably, the amount of the titanate additive is 0.5-1% of the mass of the titanium dioxide base material.

[0020] Preferably, the titanate additive is an alcohol amine chelated titanate.

[0021] Preferably, after the aluminum trihydroxide coating in step S2, the slurry pH is adjusted to 6.0-6.5, and then the slurry is pressure filtered and washed with water, and the water-washed filter cake is subjected to step S3 of steam powdering.

[0022] The present application improves the compatibility with spinning raw materials by using an organic dispersing agent in the coating slurry process, and then improves the weather resistance of titanium dioxide by zirconium silicate coating, and further improves the water dispersibility of titanium dioxide by the condensation of aluminum trihydroxide coating and a titanate additive, so that the extinction and weather resistance of the chemical fiber are improved. BRIEF DESCRIPTION OF DRAWINGS

[0023] Fig. 1is a weather resistance test picture of the product of Example 1;

[0024] Fig. 2 is a weather resistance test picture of the product of Example 2;

[0025] Fig. 3 is a weather resistance test picture of the product of Example 3;

[0026] Fig. 4 is a weather resistance test picture of the product of Comparative Example 4;

[0027] Fig. 5 is a weather resistance test picture of the product of Comparative Example 5;

[0028] Fig. 6 is a weather resistance test picture of the product of Comparative Example 6. DETAILED DESCRIPTION

[0029] The application provides a preparation method of titanium white powder for chemical fibers, comprising the following steps:

[0030] S1. preparing a titanium dioxide-based material slurry: taking titanium white powder base material, adding an organic dispersant to prepare a titanium dioxide-based material slurry;

[0031] S2. coating: taking the titanium dioxide-based material slurry, sequentially performing zirconium silicate coating and trihydroxy aluminum stone coating;

[0032] S3. steam powdering: taking the coated material, adding a titanate additive to perform steam powdering to obtain titanium white powder.

[0033] In the slurry preparation process, the application adds an organic dispersant, which improves the uniformity of the coating and the compatibility with the spinning raw material; then zirconium silicate coating is adopted, zirconium and titanium are homologous elements, so the affinity and adhesion of zirconium to TiO2 particles are relatively strong, and the zirconium silicate is an amorphous body, which can be uniformly and stably deposited on the surface of TiO2 particles, and the zirconium silicate has strong oxidation resistance, which can improve the weather resistance of the titanium white powder; the outermost layer of trihydroxy aluminum stone coating has more hydroxyl groups on the surface compared with boehmite aluminum oxide and amorphous aluminum oxide, the hydroxyl groups can perform a chemical condensation reaction with the alkoxy groups in the titanate dispersant added in the steam powdering stage at high temperature, which increases the double electric layer and reduces the specific surface energy, and further improves the dispersibility of the titanium white powder. Moreover, the hydrophilic groups contained in the titanate can interact with water molecules in the water-soluble natural fibers in the chemical fiber, improving the dispersibility of the titanium white powder in water.

[0034] Therefore, the application improves the compatibility with the spinning raw material by using the organic dispersant in the envelope pulping process, and then improves the weather resistance of the titanium dioxide by using the zirconium silicate envelope, and further improves the water dispersibility of the titanium dioxide by the condensation of the trihydroxy aluminum stone envelope and the titanate additive, so that the extinction and weather resistance of the chemical fiber are improved.

[0035] Preferably, the titanium dioxide base material in step S1 adopts the rutile titanium dioxide with better weather resistance and stability. However, it is necessary to note that the rutile titanium dioxide particles need to be fully ground and classified, and preferably ground to an average particle size of ≤0.305 μm.

[0036] Preferably, the organic dispersant is monoisopropanolamine, and the addition amount is 0.05-0.1% of the mass of the titanium dioxide base material. The monoisopropanolamine is a small-molecule organic dispersant, which can better improve the compatibility with the downstream customer chemical fiber system.

[0037] Preferably, after the addition of the organic dispersant in step S1, the titanium dioxide base material slurry is obtained by beating, grinding and classification; and the grinding is to an average particle size of ≤0.305 μm.

[0038] Preferably, step S2 of the zirconium silicate envelope further comprises the following steps:

[0039] The pH of the titanium dioxide base material slurry is adjusted to 9.5-10, and the pH adjustment time is preferably 5-10 min, then the silicon source and the zirconium source are added, and the zirconium silicate envelope layer is obtained after aging.

[0040] Preferably, the amount of the silicon source and the zirconium source is respectively 0.6-0.8% and 0.4-0.6% of the mass of the titanium dioxide base material, calculated as SiO2 and ZrO2. The silicon source is preferably an alkaline silicon source such as Na2SiO3 and K2SiO3, and the zirconium source is preferably an acidic zirconium source such as ZrOCl2. The silicon source and the zirconium source are preferably added in sequence, the silicon source is added for 5-10 min, and the zirconium source is added for 20-30 min. By slowly adding the acidic zirconium source, the pH of the slurry gradually decreases, and the zirconium silicate gradually precipitates on the surface of the titanium dioxide particles to form a zirconium silicate envelope layer.

[0041] Preferably, step S2 of the trihydroxy aluminum stone envelope further comprises the following steps:

[0042] The pH of the titanium dioxide base material slurry with the zirconium silicate envelope layer is adjusted to 10.0-10.5, and the pH adjustment time is preferably 5-10 min, then the aluminum source and the pH adjusting agent are added in parallel flow, the parallel flow pH is maintained at 10.0-10.5, and the parallel flow time is 30-40 min; under the condition of pH 10.0-10.5, the formed aluminum oxide crystal type is trihydroxy aluminum stone, and therefore the trihydroxy aluminum stone envelope layer is obtained after aging.

[0043] Preferably, the amount of aluminum source is 2-3% of the mass of the titanium dioxide substrate, calculated as Al2O3.

[0044] Preferably, the zirconium silicate coating and the bayerite coating are performed at 70-80°C; the coating slurry concentration is 300-350 g / L.

[0045] The silicon source, the zirconium source and the aluminum source are preferably added in the form of a solution, the solution concentration being 100-150 g / L, 100-150 g / L and 100-200 g / L, respectively, calculated as the respective oxide.

[0046] Preferably, the amount of titanate additive is 0.5-1% of the mass of the titanium dioxide substrate.

[0047] Preferably, the aluminum source can be NaAlO2 and KAlO2, etc.

[0048] Preferably, the titanate additive is an alcohol amine chelated titanate with good water solubility.

[0049] Preferably, after the bayerite coating of step S2, the process further comprises the step of adjusting the pH of the slurry to 6.0-6.5, then the slurry is pressure filtered and washed with water, and the water-washed filter cake is then subjected to the step S3 of steam powdering.

[0050] The processes not defined in the present application, such as water washing and steam powdering, are all performed by using the conventional methods in the art.

[0051] Example 1

[0052] (1) Base material

[0053] ① After the titanium dioxide base material is crushed, 0.05% of monoisopropanolamine is added for slurry preparation;

[0054] ② The slurry is introduced into a sand mill for grinding to PS = 0.302 μm;

[0055] ③ The ground slurry is subjected to classification and removal of large particles and impurities by a cyclone and a vibrating screen, and if necessary, by a multi-stage cyclone.

[0056] (2) Coating

[0057] ① The slurry concentration of the titanium dioxide material prepared in (1) is adjusted to 340 g / L, the temperature is raised to 75°C and the stirring is started;

[0058] ② The pH of the slurry is adjusted to 9.5 by NaOH, and the pH adjustment time is 5 min;

[0059] ③ 0.6% of Na2SiO3 solution is added to the slurry, and the addition time is 5 min;

[0060] (4) Adding 0.4% ZrOCl2 solution to the slurry, and the adding time is 20 min;

[0061] (5) Adjusting the pH of the slurry to 10.0 by NaOH, and the pH adjusting time is 5 min;

[0062] (6) Adding 3% NaAlO2 and H2SO4 in parallel flow, and the parallel flow pH is 10.0, and the parallel flow adding time is 40 min;

[0063] (7) Adjusting the pH to 6.0-6.5 by H2SO4.

[0064] (3) The filter cake after water washing of the above slurry is fed into a flash dryer, and 1.0% alcohol amine chelated titanate is added at the same time;

[0065] (4) Steam powdering, and the titanium dioxide product is obtained.

[0066] Example 2

[0067] (1) Base material

[0068] (1) Base material

[0069] (1) Base material

[0070] (1) Base material

[0071] (2) Coating

[0072] (1) Base material

[0073] (1) Base material

[0074] (1) Base material

[0075] (1) Base material

[0076] (1) Base material

[0077] (1) Base material

[0078] ⑦ Adjust the pH to 6.0–6.5 with H2SO4.

[0079] (3) The filter cake after the above slurry is washed with water is fed into a flash dryer, and 0.5% alcoholamine chelate titanate is added at the same time;

[0080] (4) Gas powder is used to obtain titanium dioxide finished product.

[0081] Example 3

[0082] (1) Base material

[0083] ① After the solid material is crushed, 0.1% monoisopropanolamine is added for pulping;

[0084] ② The slurry is fed into a sand mill for grinding until PS = 0.300 μm;

[0085] ③ The ground slurry is graded and large particles and impurities are removed by passing it through hydrocyclones and vibrating screens. If necessary, multi-stage hydrocyclones can be used.

[0086] (2) Encapsulation

[0087] ① Adjust the concentration of the titanium dioxide slurry prepared in (1) to 308 g / L, raise the temperature to 70°C and start stirring;

[0088] ② The pH of the slurry was adjusted to 10.0 using NaOH for 5 minutes;

[0089] ③ Add 0.7% Na2SiO3 solution to the slurry over a period of 5 minutes;

[0090] ④ Add 0.5% ZrOCl2 solution to the slurry over a period of 20 minutes;

[0091] ⑤ The pH of the slurry was adjusted to 10.5 using NaOH for 5 minutes;

[0092] ⑥ Add 2.5% NaAlO2 and H2SO4 in a co-current flow at a pH of 10.5 for 30 min.

[0093] ⑦ Adjust the pH to 6.0–6.5 using H2SO4.

[0094] (3) The filter cake after the above slurry is washed with water is fed into a flash dryer, and 0.7% alcoholamine chelate titanate is added at the same time;

[0095] (4) Gas powder is used to obtain titanium dioxide finished product.

[0096] Comparative Example 1 (Normal Base Material)

[0097] (1) Base material

[0098] The inorganic dispersant (sodium hexametaphosphate) is used instead of the organic dispersant monoisopropanolamine for beating, and other steps are the same as in Example 3.

[0099] (2) Coating

[0100] ① The concentration of the titanium white slurry prepared in (1) is adjusted to 308 g / L, the temperature is raised to 70°C, and stirring is started;

[0101] ② The pH of the slurry is adjusted to 10.0 using NaOH, and the pH adjustment time is 5 min;

[0102] ③ 0.7% Na2SiO3 solution is added to the slurry, and the addition time is 5 min;

[0103] ④ 0.5% ZrOCl2 solution is added to the slurry, and the addition time is 20 min;

[0104] ⑤ The pH of the slurry is adjusted to 10.5 using NaOH, and the pH adjustment time is 5 min;

[0105] ⑥ 2.5% NaAlO2 and H2SO4 are added in parallel flow, the parallel flow pH is 10.5, and the parallel flow addition time is 30 min;

[0106] ⑦ The pH is adjusted to 6.0-6.5 using H2SO4.

[0107] (3) The filter cake after water washing of the above slurry is fed into a flash dryer, and 0.7% titanium chelate acid ester of alcohol amine is added at the same time;

[0108] (4) Steam powdering, and the finished product of titanium white powder is obtained.

[0109] Comparative Example 2 (without adding titanium chelate acid ester dispersant)

[0110] (1) Base material

[0111] ① The solid material is crushed, and 0.1% monoisopropanolamine is added for beating;

[0112] ② The beaten material is introduced into a sand mill for grinding, and the grinding is performed to PS = 0.300 μm;

[0113] ③ The ground slurry is classified and the large particles and impurities are removed by a cyclone and a vibrating screen, and if necessary, a multi-stage cyclone can be used.

[0114] (2) Coating

[0115] ① The concentration of the titanium white slurry prepared in (1) is adjusted to 308 g / L, the temperature is raised to 70°C, and stirring is started;

[0116] (2) Adjusting the pH of the slurry to 10.0 with NaOH, the pH adjusting time being 5 min;

[0117] (3) Adding 0.7% Na2SiO3 solution to the slurry, the adding time being 5 min;

[0118] (4) Adding 0.5% ZrOCl2 solution to the slurry, the adding time being 20 min;

[0119] (5) Adjusting the pH of the slurry to 10.5 with NaOH, the pH adjusting time being 5 min;

[0120] (6) Adding 2.5% NaAlO2 and H2SO4 in parallel flow, the parallel flow pH being 10.5, the parallel flow adding time being 30 min;

[0121] (7) Adjusting the pH to 6.0-6.5 with H2SO4.

[0122] (3) The above slurry is washed with water, flash dried and steam pulverized to obtain the finished product of titanium dioxide.

[0123] Comparative Example 3

[0124] Foreign Standard Sample S.

[0125] 1. Water dispersibility test

[0126] The dispersibility of the products of Examples 1-3 and Comparative Examples 1-3 was determined by the following method, and the results are shown in Table 1.

[0127] Water dispersibility test method:

[0128] (1) 285 mL of deionized water and 15 g of titanium dioxide sample were placed in a 500 mL conical flask, and a magnetic stirrer was used for dispersion;

[0129] (2) 10 mL was immediately taken, dried and tested for solid content 1;

[0130] (3) After the slurry obtained in step (1) was allowed to stand for 5 h, the slurry at a height of 17 cm was taken, and after dispersion, 10 mL was immediately taken, dried and tested for solid content 2;

[0131] (4) The water dispersibility was calculated: water dispersibility = solid content 2 / solid content 1*100%

[0132] Table 1

[0133]

[0134] 2. Weather resistance test

[0135] The weather resistance of the products of Examples 1 to 3 and Comparative Examples 1 to 3 of the present application was tested in a PVC system, and the testing method was as follows: 50 g of PVC resin + 2 g of titanium white powder sample + 5 g of lead salt stabilizer were rolled at 180 °C for 3 min to form a sheet, which was then placed in a water-sealed bag to remove air, and then exposed to a xenon lamp for 2 to 4 h, after which the color of the sample sheet was observed. The results are shown in Table 1. Figs. 1-6 The higher the whiteness, the better the weather resistance.

[0136] As can be clearly seen from Table 1 and Figs. 1-6 The water dispersibility and weather resistance of the examples are both significantly better than those of the comparative examples.

[0137] Although preferred embodiments of the application have been described, those skilled in the art will be able to make additional changes and modifications to these embodiments once they have the basic inventive concept. Therefore, the appended claims are intended to be interpreted as including all the preferred embodiments and all changes and modifications falling within the scope of the present application. Obviously, those skilled in the art can make various modifications and changes to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and changes of the present application fall within the scope of the claims of the present application and equivalent technologies thereof, the present application is also intended to include these modifications and changes.

Claims

1. A method for producing titanium white for synthetic fibers, characterized by, The method comprises the following steps: S1. Preparing a titanium dioxide-based material slurry: taking a titanium white base material, adding an organic dispersant to prepare a titanium dioxide-based material slurry; the titanium white base material is rutile titanium dioxide; the organic dispersant is monoisopropanolamine, and the addition amount is 0.05-0.1% of the mass of the titanium white base material S2. Coating: taking the titanium dioxide-based material slurry, sequentially performing zirconium silicate coating and trihydroxy aluminum stone coating; The zirconium silicate coating further comprises the following steps: adjusting the pH of the titanium dioxide-based material slurry to 9.5-10, sequentially adding a silicon source and a zirconium source, and obtaining a zirconium silicate coating layer after aging; the silicon source is an alkaline silicon source, and the zirconium source is an acidic zirconium source; The trihydroxy aluminum stone coating further comprises the following steps: adjusting the pH of the titanium dioxide-based material slurry coated with the zirconium silicate coating layer to 10.0-10.5, then adding an aluminum source and a pH adjuster in parallel flow, keeping the parallel flow pH at 10.0-10.5, and obtaining a trihydroxy aluminum stone coating layer after aging; S3. Steam powder: taking the coated material, adding a titanate additive to steam powder, and obtaining titanium white; the titanate additive is an alcohol amine chelated titanate.

2. The method for preparing titanium white for chemical fibers according to claim 1, characterized in that, after adding the organic dispersant in step S1, the titanium dioxide-based material slurry is obtained through beating, grinding and grading; the grinding is performed to an average particle size of ≤0.305 μm.

3. The method for preparing titanium white for chemical fibers according to claim 1, characterized in that, the amounts of the silicon source and the zirconium source are 0.6-0.8% and 0.4-0.6% of the mass of the titanium dioxide-based material, respectively, calculated based on SiO2 and ZrO2.

4. The method for preparing titanium white for chemical fibers according to claim 1, characterized in that, the amount of the aluminum source is 2-3% of the mass of the titanium dioxide-based material, calculated based on Al2O3.

5. The method for preparing titanium white for chemical fibers according to claim 1, characterized in that, the amount of the titanate additive is 0.5-1% of the mass of the titanium dioxide-based material.

6. The method for preparing titanium white for chemical fibers according to claim 1, characterized in that, after the trihydroxy aluminum stone coating in step S2, the method further comprises the step of adjusting the pH of the slurry to 6.0-6.5, then filtering and washing the slurry, and performing the steam powder in step S3 on the water-washed filter cake.

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