Papers by Author: Hao Ding

Abstract: To obtain a kind of composite particles material which has the property of both fly ash glass beads (FA) and titanium dioxide (TD), chemical hydrolysis precipitation method was adopted. Each process condition was investigated and the results were characterized by titanyl sulfate hydrolysis rate and the effect of FA coated TD. Composite structure and properties were characterized by means of X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), Fourier Transform Infrared Spectroscopy (FTIR) and testing physical properties of FA/TD. The results show that the surface of FA has been coated with TD uniformly and compactly after titanyl sulfate hydrolysis and cladding content roasted. The optimal preparation conditions are hydrolysis cladding temperature 100°C, time 180min, matrix slurry concentration 0.5%, titanyl sulfate solution dosage 0.5g/g and titanyl sulfate solution drop way for the graded way. The hiding power and whiteness of the composite powder are respectively 35.47 g/m2 and 54.43. The results also show that the composite powder has similar pigment performances with TD and it is much whiter than material.

Abstract: The structure of sericite is very stable, so it is hard to peel it directly using traditional methods. In this article, the sericite which was processed through thermal activation, acid treatment, Na-modification and CTAB intercalation was used as raw material to do the exfoliation. The mechanical exfoliation method and ultrasonic method were used respectively to exfoliate the modified sericite. The grain size of final product using mechanical exfoliation method reached 16.6nm and the grain size of final product using ultrasonic method reached 8.1nm. Alongside with the result of TEM images, the ultrasonic method is thought to be better.

Abstract: Stellerite was activated and organic modified by calcination and hexadecyl trimethyl ammonium chloride (CTAC) to improve its adsorpability of formaldehyde which was one of the iconic pollutants of indoor air pollution. Results showed that the optimum calcining temperature and calcining time were 300 °C and 1.5 h. The optimum amount of anticoagulant, alcohol addition, CTAC addition, bathing temperature and reaction time were 0.5%, 0.7ml, 3 times, 70 °C and 2h, respectively. The organic modified effects of stellerite were characterized by hygroscopicity test, formaldehyde adsorption experiment, scanning electron microscopy (SEM) and fourier transform infrared spectroscopy (FT-IR). All data indicated that CTAC had entered into the internal of stellerite and the adsorbability of formaldehyde had a huge improvment after organic modification.

Abstract: Although sericite belongs to 2:1 clay minerals, it hardly has intercalation properties because it has high layer charge density, which produces pretty strong electrostatic force. Therefore, the purpose of activation is to permanently reduce the layer charge of sericite and obtain numbers of exchangeable cations. The original sericite (S₀) was sintered at 800 °C for 1 h. After that, thermal-treated sericite (S₁) was activated with sodium fluosilicate and nitric acid, whose effects were characterized by X-ray diffraction (XRD) analysis, chemical analysis and zeta electric potential analysis. The dissolving-out amount of Al³⁺ of acid-treated product (S₂) reached circa 65 mg/g at the optimal processing conditions. After sodium modification with NaCl, CEC of final resulting product (S₃) was increased to 14.34 meq/100g compared with that of original sericite (4.94 meq/100g). The results of chemical analysis and zeta electric potential analysis indicated that acid activation with sodium fluosilicate and nitric acid decreased the layer charge of sericite.

Abstract: Sericite-TiO₂ composite particle material was prepared via mechano-chemical method. SEMEDS and XPS ananlysis indicates that the surface of the sericite were coated by the TiO₂ layers and the Ti⁴⁺ cations were anchored by formation of SiOTi bonds. Otherwise, the TiO₂-coated sericite powders have higher light scattering indexes and other more outstanding properties than the naked sericite powders. Especially, the whiteness, adsorbed value, and hiding power indexes of the rutile TiO₂-coated sericite powders were higher than those of the anatase TiO₂-coated sericite powders. Hence, rutile TiO₂-coated sericite powders can be substitute for the titanium dioxide pigment.

Abstract: The structure of sericite is stable, and it is hard to prepare polymer layered silicate nanocomposites (PLSN). Therefore, structural modification was employed to activate sericite to reduce the layer charger. The thermal treated sericite (S₁) was prepared by thermal modification at 800 for one hour. Then, the resulting product was modified with sodium fluorosilicate, whose effect was characterized by X-ray diffraction (XRD) analysis. The dissolving-out amount of Al³⁺ of salt-treated product (S₂) reached circa 2.55 mg/g at the optimal processing conditions. CEC of S₂ was increased to 10.52 meq/100g compared with that of original sericite (4.94 meq/100g). The results of XRD analysis indicated that mica-type phase persisted after salt modification with sodium fluosilicate.

Abstract: The dispersity of nanosized calcium carbonate modified by alkyl amine dimethyl phosphonic acid (WTP-08) through mechano-chemical method in different media was investigated. The modification mechanism was investigated by analyzing the surface energy and its thermodynamic effect on dispersity of nanosized calcium carbonate. The results show that the free energies of nanosized calcium carbonate modified by WTP-08 and its interfacial free energies in air and non-polar media decrease significantly, while the interfacial free energy in water increases remarkably. It can be concluded that modification by WTP-08 improves the dispersion tendency of nanosized calcium carbonate in air and non-polar medium, while it decreases in water. Therefore, modification by WTP-08 makes the dispersity of nanosized calcium carbonate increase in air and non-polar medium and decrease in water.

Abstract: The reaction mechanism between Zn²⁺ and diatomite in preparation of Zn²⁺/diatomite antibacterial agent by diatomite adsorbing and solidifying Zn²⁺ in its pores was studied. Microporous adsorption, characterized by hydrated Zn²⁺ adsorbed in the micropores of diatomite, and surface coordinate adsorption, featured with coordination of Zn²⁺ with functional groups on the surfaces of diatomite, were the main adsorption ways accompanied by ion exchange adsorption and physical adsorption. SEM was used to observe the morphologies of diatomite before and after adsorption. Due to the dehydration between OH groups on the surfaces of diatomite when heat treated at high temperature, Si-O-Zn bonds were formed, combining Zn²⁺ with diatomite together. Reaction model between Zn²⁺ and diatomite was established.

Abstract: Preparation of amorphous silica using Zr-containing silica residue and the properties of the product have been studied. The results show that the separation of amorphous silica from Zr component can be realized using a process flow that pulping, grinding, washing and solid-liquid separation. The main constituent of the product is amorphous state, the content of SiO₂ in the product comes up to 94.3%, the content of ZrO₂ comes up to 7.48%, the grain size is 2-3 μm, the surface area is 494.3 m²/g. The quality of the recovery can meet the requirement of white carbon black standards ISO 5794-1 and HG/T 3061.

Abstract: The amorphous silica was prepared from the alkali wastewater rich in Na₂O•nSiO₂ produced in manufacturing process of zirconium oxychloride (ZrOCl₂). The composition and microstructure of amorphous silica were studied by X-ray diffraction, X-ray fluorescence and scanning electron microscope, respectively. The results showed that the amorphous silica was mainly composed of uncrystallized substance, and the silica content was 96.4%. Its whiteness was 97.5% and the particle size was between 100nm and 200nm without agglomeration. The specific surface area of the amorphous silica was 531.9 m²/g, and its pore volume and diameter were 0.945 cm³/g and 4.94 nm, respectively.