Powder Technology and Application

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Authors: Zheng Xu, Shou Ci Lu
Abstract: A new electrostatic dispersion device was designed to reduce the agglomeration of fine powder in the air. This device is using the repulse force between particles which charged the same charge to prevent the particles from reuniting. The effects of charge voltage, particle size, the distant between electrode, and moisture content on the dispersion degree of the powder are discussed. The invalidation time of the electrostatic dispersion is also highlighted in the paper. The results show that the electrostatic dispersion is an effective method for the fine powders in the air. The charge voltage is the most important parameter for the dispersion. Middle size particle got best dispersion. When the distance between the electrodes is 24cm, the dispersion degree reaches the maximum. The humidity of the powder not only affects the charge of the powder, but also affects the dispersion degree of the powder.
Authors: Xiang Zhong Ren, Pei Xin Zhang, Jian Hong Liu, Qian Ling Zhang
Abstract: Ag/polypyrrole(PPy) composite nanoparticles within 100 to 150nm diameter were successfully synthesized. Fourier transform infrared spectroscopy(FTIR) and X-ray diffraction patterns(XRD) data suggested that the nanoparticles were composed of Ag and PPy. An amperometric glucose biosensor was fabricated by adsorbing of glucose oxidase(GOx) to an Ag/PPy nanoparticle-ethyl cellulose composite material modified platinum electrode. The biosensor exhibited a super highly sensitive response to the analyte with a detection limit of 1.0×10-7mol/L. Moreover, the biosensor showed quick current response. The effects of some factors, such as working voltage, pH value , mensuration temperature and mass ratio of Ag/PPy nanoparticles to ethyl cellulose, were also studied.
Authors: Xiao Hua Liu, Xing Dong Lv, Jian Xia Fu, Peng Peng, Guo Sheng Gai
Abstract: Silica fume is the dust recovered from the smoke released while smelting Si or Si-Fe alloy. The papers gives an overview of silica fume application in concrete, refractory, metallurgy and cement in China, along with some projects as examples; To contrast the situation at abroad, the producing, application, and price of silica fume in China was analyzed, and base on this predicted the future market. It is significant to promote deep research and application for silica fume.
Authors: Yu Liang An, Yan Qiu Liu, Xia Yuan
Abstract: A novel and practical route for preparing carbon nanocapsules using biomass – starch as the starting materials was presented. Carbon nanocapsules can be effectively synthesized by catalytic carbonizing starch in hydrogen flow. The carbohydrate was carbonized in a controllable way that leads to a large amount of carbon cages nanoparticles under Fe catalyst. Transmission electron microscopy (TEM), energy dispersive X-ray (EDX) and X-ray diffraction (XRD) were employed to characterizing carbon nanomaterials. The growth mechanism of carbon nanocapsules is briefly discussed in term of composition of precursor.
Authors: Zhen Fu Lu, Wan Zhong Yin, Xiao Liang Chang, Yue Xin Han
Abstract: A lager amount of iron ore is to be exploited in Yezhugou region, Liaoning Province. Analysis indicated that the main valuable mineral was fine-grained hematite and the total iron content was 28.22%. A process flowsheet of gravity concentrtion - high intensity magnetic separartion – reverse flotation was established, and operating conditions of each operation were also determined through batch tests. In closed-circut tests under the same operation conditions, the following results were obtained: iron content of the concentrate 64.95%, concentrate recovery 81.04%, and iron content of the tailings 8.26%.
Authors: Qing Guo Tang, Jin Sheng Liang, Jun Ping Meng, Fei Wang, Li Wei Li, Yang Xian Li
Abstract: Mineral attapulgite powders were heat treated at different temperature from 100°C to 800°C. The effect of heat treatment on properties of attapulgite were studied by particle size distribution, surface free energy, and water vapor adsorption performance. The results show that the medium particle size and surface free energy of attapulgite increase and hygroscopic capacity promptly reduce with the increase of heat temperature .The medium particle size of the raw palygorskite is 3.09 μm, and it becomes 14.12 μm after heat treatment at 800 °C. The surface free energy, polarity component and dispersion component of the natural attapulgite are 45.16mN•m-1, 13.92mN•m-1, 31.24mN•m-1, respectively, and they become 116.22 mN•m-1,116.22 mN•m-1,0.0 mN•m-1 after heat treatment at 800°C. Moreover, the hygroscopic capacity of attapulgite in 24h decreases from 17.1 % to 5.6% after heat treatment at 800°C.
Authors: Gang Xue, Xiao Ming Wu, Jin Sheng Liang, Yan Ding, Li Hua Liu
Abstract: The powders of mineral materials with far infrared radiation (CTTP) were prepared using rare earth cerium nitrate, tourmaline and transition metal oxide by coprecipitation, and calcination at 1073K for 3h. The inorganic-organic mineral composite materials with far infrared radiation (CTTR) were prepared from CTTP and resin according to the weight ratio of 4:6. It was found by characterization with scanning electron microscope (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscope (FTIR), that the infrared radiance of the CTTR was 93%. The effects of the CTTR on the surface tension and the kinematic viscosity of diesel oil as well as the effects of the CTTR on oil consumption and air pollutant emissions of oil-burning boiler were investigated in this paper. The results showed that the diesel oil dealted with the CTTR resulted in the strengthenty of molecular movement and the decrease of intermolecular contacts. In laboratory, the surface tension of diesel oil was reduced from 27.287 to 27.254 mN/m and the kinematic viscosity of diesel oil was reduced from 2.85 to 2.81 mm2s-1. The oil-saving rate of the RBS•VH-1.5 boiler treated with the CTTR could reach 4.57%, and the reducing rates of CO and NO in the exhaust gas were 1.30 and 4.08%, respectively.
Authors: Jing Hui Wang, Xin Li, Jun Wei Ye, Yuan Lin, Gui Ling Ning
Abstract: In this paper, magnesium hydroxide (Mg(OH)2) nanoparticles with tunable morphologies have been selectively synthesized via a facile template-free solvothermal route. The as-synthesized samples were characterized by instrumental analyses such as transmission electron microscopy (TEM) and X-ray powder diffraction (XRD). It was found that the morphology and size of the final products strongly depended on the reaction temperature and duration time. By manipulating the temperature and time in the solvothermal treatment, fiber-like, sphere-like and garland-like magnesium hydroxide nanoparticles were obtained. The described method without any catalysts or templates for preparing magnesium hydroxide nanoparticles is promising for industrial production in competition with other approaches.

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