Ling Ke Zeng

Effect of Calcination Temperature on Mineral Composition of Carbide Slag, Lime Activity and Synthesized Xonotlite

The calcined carbide slag was used to prepare xonotlite by replacing quicklime as the calcareous materials. Effects of calcination temperature on the mineral composition of the carbide slag, lime activity and synthesized xonotlite were studied. The results indicated that carbide slag after proper calcination can be used to prepare xonotlite. Calcination temperature has no effect on the synthesized xonotlite, but has a great impact on lime activity and morphology of secondary particles of xonotlite.

Preparation of Nanoporous Super Thermal Insulation Material Compounded with Xonotlite-SiO2-Aerogel and Characterization of the Pore Structure

Ultra-light calcium silicate material constructed with fibrous xonotlite crystals has an advantage of low-thermal conduction coefficient. But the microporous structure can hardly make a better performance in terms of super thermal insulation. Although nanoporous structure of SiO2-aerogel satisfies the requirement, its tenacity is not strong enough to produce by itself blocky super thermal insulation material. This research, thus proposes to apply SiO2-aerogel as nanoporous carrier in the process of preparation, with Ultra-light calcium silicate material constructed with fibrous xonotlite crystals as the matrix so as to prepare nanoporous super thermal insulation material compounded with Xonotlite-SiO2-aerogel via so-gel method and ethanol supercritical drying. SEM and pore size distribution techniques were here applied to characterize the morphology and pore structure of the composite material. The results show that the SiO2-aerogels were better distributed in pore of calcium silicate matrix, with the pore size distribution of composite ranging from 10 nanometers to 50 nanometers, and average pore size less then 20 nm.

Hydrothermal Synthesis of Xonotlite Fibers and Investigation on their Thermal Property

A hydrothermal route for preparing large size xonotlite fibers without special instruments and synthesis conditions was development. Effect of pH values in system on the crystal phase and morphology of synthesized xonotlite fibers was studied by using XRD and SEM. The results indicated that the different pH systems have little effect on the crystallinity of synthesized xonotlite, but have great impact on the morphology of xonotlite fibers. The higher pH value is, the lager scale xonotlite fibers appear when the pH values are among 12.0, 12.5, 13.0 and 13.5. The formation of xonotlite fibers was promoted and xonotlite fibers with 10-30 μm in length and 100-200 nm in diameter were prepared at 220 °C for 15 h in the system of pH 13.5. The evaluation of thermal property revealed that synthesized fibers were excellent in thermal stability at high temperature, and could be potential candidate as reinforcement reagents in composite areas.

Photocatalytic Degradation of Methyl Orange on ZnO in Aqueous

The photocatalyst of nanometer ZnO powder was prepared by precipitation method with ZnSO4⋅7H2O and Na2CO3 as raw materials. Laboratory experiments with methyl orange (MO) as the model pollutant have been carried out to evaluate the photocatalytic activity of nanometer ZnO photocatalyst. A high-pressure mercury lamp was used as the energy source for the photocatalytic experiments. The effects of process parameters such as catalyst loading, initial methyl orange concentration, pH and electrolyte on the photodegradation have been investigated.

Microwave Synthesis of Nano-Titanium Carbide

A new synthesis technology of titanium carbide with microwave is introduced in this article. Microwave synthesis technology is a fast and relatively low temperature of synthesis method. Nano-titanium carbide powders were synthesized by carbothermal reduction of titanium dioxide and carbon black with the microwave synthesis method at 1100°C-1400°C in argon gas atmosphere. Nano-TiO2 powder and carbon black were used as raw materials. The TiC powders were characterized with the XRD and TEM. The experimental results show that the synthesis rate is quick, even at relatively low synthesis temperature. The average particle size of the TiC powders synthesized by the microwave synthesis technology under low temperature (<1300°C) is less than 50nm, and the average particle size augments with increasing the microwave synthesis temperature and time.

Thermal Energy Storage System of Sulfate / Fiber Matrix Composite

The K2SO4-Na2SO4 system was studied by differential scanning calorimetry (DSC) with the aim of developing a new phase-change thermal energy storage material. The temperature range of phase change is from 800°C to 1069°C according to the phase diagram. A new shape-stabilized phase-change material made of molten salts impregnated by capillary forces in a porous-fiber matrix was presented. These materials were characterized by X-ray diffraction analysis and differential scanning calorimetry analysis. The results indicated that the compound included 70~80% of molten salts, meanwhile the heat storage material could keep its shape without any leakage during the heating process.

Preparation and Structure Characterization of Mullite Fiber Porous Ceramic

Mullite fiber porous ceramic was prepared by forced liquid displacement forming and using Mullite precursor sols as binders. SEM studies have shown that the uniformity of integral ceramic is good although the binder and fiber congregate slightly. Mullite precursor sols spread to films or congregate together in miniature. The mullite sol binders between fibers limit to the contact points and the redundant binders form flat film even if they are superfluous, and the pores were not built up even where the binders congregate badly. The results from mercury porosimetry testing of the mullite fiber porous ceramic showed the relationship of cumulative intrusion and diameter for mullite fiber porous ceramic using colloidal mullite binder, and the mean pore size is 45.6μm. The pore size distribution is very broad, from about 0.2 to 174.9μm.

Sintering Shrinkage Anisotropy of Spherical Alumina Powder Compacts with Particle Orientation

Spherical alumina powder and dispersant were mixed with distilled and deionized water, and ball milled to make alumina slurry. The slurry was dried in a high magnetic field to make a compact. Subsequently, the compact was cold-isostatic-pressed (CIP) to enhance the homogeneity in particle packing density. Anisotropy of shrinkage during sintering was examined for the alumina compacts in detail. Particle orientation existed in the spherical alumina powder compacts prepared in 10T, and made them shrink anisotropically during sintering. Sintering shrinkage was larger in the direction parallel to magnetic field direction (i.e., the c-axis direction of alumina crystal) than that in its perpendicular direction. The particle orientation structure in the compacts was confirmed with the immersion liquid method of polarized light microscope, and the grain alignment structure in the sintered bodies was also observed with X-ray diffraction, the c-plane was perpendicular to the magnetic field direction. On the other hand, isotropic sintering shrinkage occurred in the spherical alumina powder compacts prepared in 0T, which did not hold the particle orientation. The experimental results indicate that sintering shrinkage of spherical alumina powder compact depends on alumina crystal axis direction. Origin of the sintering shrinkage anisotropy for the spherical alumina powder compacts can be attributed to the particle orientation caused by high magnetic field.

Preparation and Microstructure of Bauxite Ceramic Microsphere

In this paper, microspheres were prepared by using Chinese bauxite as raw materials through centrifugal spray drying method. The microstructure and composition of ceramic microsphere were investigated by X-ray diffraction, scanning electron microscope and X-ray energy spectrum. The particle size was 10~100#m. The XRD analysis reveals that the main crystalline phase of the ceramic microsphere were α-Al2O3 and mullite (3Al2O3•2SiO2). The Al2O3 content (chemical composition) of the microspheres was little more than 70%, and the molar ratio of Al2O3/SiO2 was near to the molar ratio of alumina and silica of mullite.

Resource Recycling of Waste Slag of Aluminum Factory

In the last decade, The government and scientific researchers have payed a lot of attention to waste slag of aluminum factory . Many scholars have done a great deal of research and put forward many valuable resource recycling methods,Especially in ceramics field. This paper has reviewed the aluminum slag application ways that researched by our team and some other related scholars,and mainly overviews the application in ceramic filed.