| CHEN Jia-qi,CHEN Jian-li,ZHANG Yu-rong,WANG Yong-shan,LIU Ting-fu,CHEN Kui.Surface Modification and Establishment of Powder Flowability Evaluation Method of TiO2[J],52(7):325-335 |
| Surface Modification and Establishment of Powder Flowability Evaluation Method of TiO2 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2023.07.030 |
| KeyWord:titanium dioxide powder flowability surface modification pigment property principal component analysis |
| Author | Institution |
| CHEN Jia-qi |
School of Chemical Engineering, East China University of Science and Technology, Shanghai , China |
| CHEN Jian-li |
Longbai Group Co., Ltd., Henan Jiaozuo , China |
| ZHANG Yu-rong |
Longbai Group Co., Ltd., Henan Jiaozuo , China |
| WANG Yong-shan |
Longbai Group Co., Ltd., Henan Jiaozuo , China |
| LIU Ting-fu |
Anton Paar Shanghai Trading Co., Ltd., Shanghai , China |
| CHEN Kui |
School of Chemical Engineering, East China University of Science and Technology, Shanghai , China |
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| Abstract: |
| The flowability of TiO2 powder directly affects its pigment properties and application in subsequent fields. Currently, most of TiO2 products have the problem of poor flowability, which is manifested as bonding and agglomeration in blanking, packaging, transportation and subsequent application. The existing research on the flowability of powder mainly focuses on the flowability difference caused by particle size of micron powder such as food, medicine and pulverized coal, while there is little research on the flowability of submicron powder. To date, the research on the flowability of TiO2 powder has not been reported by scholars in China or abroad. The work aims to establish a comprehensive performance evaluation method of TiO2 based on powder flowability and pigment properties to guide the optimization of surface modification process and obtain titanium dioxide products with excellent flowability and pigment properties. The effects of the impact different surface properties on TiO2 flowability and pigment properties were compared with those on TiO2 of the same particle size and size distribution. With chloride rutile TiO2 as the base material, Zr/Al inorganic coating and organic coating were carried out in sequence. The effects of key coating parameters on the flowability and pigment properties of coated TiO2 products were investigated. By changing the alumina content (1.0%, 2.0%, 3.0%, 4.0%, 5.0% in terms of TiO2 mass) in Zr/Al inorganic coating, and maintaining the same organic coating conditions, the effect of inorganic coating on powder performance was explored. After the optimal inorganic coating was determined, the effect of organic coating on TiO2 powder performance was explored by maintaining the same inorganic coating condition and coating TiO2 samples with different additions of TMP and TME (0.0%, 0.2%, 0.4%, 0.6%, 0.8%, 1.0% based on the mass of TiO2). The compressibility, wall friction and shear action of TiO2 powder were tested by powder rheometer, and characteristic index parameters such as Hausner ratio, wall friction angle and internal friction angle were obtained to characterize flowability. The inorganic element content of TiO2 was measured by X-ray fluorescence diffractometer, the crystal form of TiO2 was determined by X-ray diffraction analyzer, the particle size and particle size distribution of powder were measured by laser particle size analyzer, and the surface morphology of powder was analyzed by scanning electron microscope. The pigment properties of TiO2 were evaluated by gloss, tint strength and coverage. Based on the above parameters, principal component analysis method was used to evaluate the comprehensive performance of TiO2. The experiment results indicated that the inorganic coating had great effect on the pigment properties of TiO2 powder, but small impact on its flowability. In contrast, the organic coating had great significance on the flowability of TiO2 powder. For Zr/Al inorganic coating, hydrated alumina firstly formed a continuous dense coating layer on the surface of powder particles due to heterogeneous nucleation and then homogeneously nucleated to form a loose and flocculent Boehmite-type coating layer. When aluminum content was 2.0%-3.0%, the powder had better pigment properties and flowability. For organic surface modification, when TMP content was 0.4% or TME content was 0.2%, the product maintained good pigment properties and excellent flowability, while the production cost was relatively low. In conclusion, for TiO2 with same base material (D50=0.354 μm), the amount of aluminum added in Zr/Al inorganic coating and the type and amount of organic coating agent will affect the surface properties, resulting in the difference in flowability and pigment properties. With the characteristic indicators selected in this paper, the comprehensive performance evaluation method of TiO2 powder established by principal component analysis can be used to guide the optimization of the coating process. |
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