Papers by Author: Hong Shun Hao

Abstract: Silicon carbide powders were prepared by the carbothermal reduction method. The starting powders used were iron tailings and graphite. The XRD results showed that the main crystal phase was SiC and the main impurity was FexSiy in as-fabricated silicon carbide. The SEM results revealed that the grains of SiC-phase in as-fabricated silicon carbide were flaky-like or globular-like. It is found that the carbon addition and the reaction temperature play a key role to obtain SiC-phase, while the holding time and argon flow rate had a little effect on the yield of SiC as the excessive carbon addition are used. The optimum sintering temperature, holding time, argon flowing rate, the ratio of n(C): n(SiO2) are 1500 °C, 8 h, 0.6 L/min, 5:1, respectively.

Abstract: The output quantity of iron tailings increases rapidly with the development of metallurgical industry and the growth of the requirement for minerals in the world, which could cause severe hazard to our environment. Therefore, it is very important to recover and reuse these tailings to protect the environment and use natural resources effectively. In this paper, the Fe-Si-Ti multiphase composite ceramic has been synthesized from the Iron ore tailings of Panzhihua region with the carbothermal reduction nitridation (CRN) method. The phases and microstructures of sintered body were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FSEM) and energy dispersive spectroscopy (EDS). The XRD pattern indicates that the main phases of the samples are Fe3Si and Ti(C0.3, N0.7). Meanwhile, FSEM and EDS show that Fe3Si is surrounded by Ti(C0.3, N0.7). Besides, the physical properties of the sample are tested, especially the wear resistance. The test results show that the synthesized Fe3Si-Ti(C0.3, N0.7) composite ceramic has good wear resistant property, high hardness and larger thermal expansion coefficient, which indicates it can be used as the abrasion-proof material or transition layer between the metal and inorganic coating. At last, based on FSEM and EDS, the microstructure and elements of the abraded surface of sample is analyzed.

Abstract: In this paper, the research mainly focused on utilization of iron ore tailing of Panzhihua region. Based on the analysis of its components, Carbothermal Reduction Nitridation (CRN) method was selected to synthesize eco-friendly composite material. Different additives were tried to improve the property of the samples. The influence of different sintering temperature, holding time and contents of additives were taken into account, and orthogonal design was employed to obtain the optimal parameters. It indicated that only when the temperature was 1450°C and the holding time was 5 hours, the samples with the bulk density of 3.42g/cm3 was obtained. The phase and surface morphology were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Experimental results showed that the phases of the product were Fe3Si and TiC0.3N0.7. The research provided a novel recycling process for ore tailings.

Abstract: O'-SiAlON/SiC ecomaterials were synthesized by using the Yangtze River sand that containing abundant Si and Al elements as the major raw material with minor additives through the carbothermal reduction nitridation route combined with colloidal process. This study realized the conversion of ecomaterials from non-traditional resources, Yangtze River sand. Orthogonal design was adopted to optimize the colloidal process parameters. The green compact with the largest bulk density was obtained when the solid volume loading is 50%, the addition mass fraction of SL is 0.8%, the addition mass fraction of CMC is 0.05%, the ball milling time is 10 h, the pH value is 9 and particle size distribution is multi-peak in the colloidal process. The effects of reduction agent, flowing rate of N2, sintering temperature during carbothermal reduction nitridation process on the microstructure of as-fabricated SiAlON materials were explored. The XRD results indicated that when sintering temperature is 1450°C, maintaining time is 6 h, flowing rate of N2 is 1.0 L/min and carbon black is selected as reduction agent, O-SiAlON/SiC composites was successfully synthesized. The SEM images showed the densificated microstructure and uniform grains with the short column shape.

Abstract: Silt from the Yellow River was mixed with a certain amount of SiO2 powder to fabricate eco-friendly silica bricks and different amounts of TiO2 were added to ameliorate the thermal conductivity of the bricks. Results showed that the phases of as-fabricated silica bricks are cristobalite and tridymite with cristobalite predominating. With increasing amounts of TiO2, the bulk density and thermal conductivity of the samples increase. Although the bulk density (1.65~1.76 g/cm3 ) than the ideal density 1.85 g/cm3, the thermal conductivity is significantly ameliorated. The thermal conductivity of the sample with 1.5% TiO2 addition is 2.11 W/m.°C, which is nearly three times higher than that of commercial silica bricks (0.8 W/m.°C).

Abstract: This presented a route to utilize the Tungsten Molybdenum Bismuth Polymetallic Tailings in Shizhuyuan of Hunan province to fabricate Ca-substitued α-Sialon eco-materials. The reaction mechanism in carbothermal reduction nitridation process was widely studied by separately considering the effect of sintering temperature and soaking time. Based on the optimized conditions, a composite containing 78% Ca-based α-Sialon has been fabricated at 1600°C for 8h.