Papers by Author: Ke Qiang Xie

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Authors: Yi Mai, Wen Hui Ma, Ke Qiang Xie, Tong Wang, Hu Zhang, Qiang Liu
Abstract: In order to find the most effective hydrometallurgical method of removing iron, aluminum and calcium from MG-Si, a variety of acid leaching methods were presented. The research results show that the order of capacity of metallic impurity removal is HF, HCl, HNO3 and H2SO4. The most effective hydrometallurgical method is the leaching by mixed acid with hydrofluoric acid and sulfuric acid. Removal efficiency of hydrochloric acid pressure leaching can improved as the pressure increases. Sulfuric acid and nitric acid even using high pressure leaching cannot obtain high impurity removal rate. The leaching by hydrofluoric acid or mixed acid containing hydrofluoric acid and sulfuric acid is very effective on removal of iron and aluminum, but less effective on calcium.
Authors: Yang Zhou, Shi Xing Wang, Ke Qiang Xie, Yong Nian Dai, Wen Hui Ma
Abstract: Chemical modified silica fume by polyaniline was studied as a sorbent for removal of chromium (VI) determined by flame atomic absorption spectrometer. TEM analysis confirmed that the mean diameter of silica fume before and after treatment was of the order of 120 nm. The functionalized nanoparticles showed an extremely high efficiency towards chromium (VI) in the pH range of 4-5. Adsorption of chromium (VI) from water using functionalized silica fume was both a simple and efficient approach compared to the traditional adsorbents from the angle of integrated utilization of the secondary resources.
Authors: Kui Xian Wei, Wen Hui Ma, Yang Zhou, Ke Qiang Xie, Bin Yang, Da Chun Liu, Yong Nian Dai
Abstract: Vacuum evaporation is usually utilized to remove volatile impurities in metallurgical grade silicon to prepare solar grade silicon by metallurgical routes. Especially phosphorus needs to be removed by vacuum evaporation. And the removal efficiency of impurities strongly influenced the quality and performance of products. In this paper, the removal efficiency of impurities is studied by using different raw material. The results indicated that the content of impurities in raw material had deep effect on the removal efficiency of vacuum evaporation. The high quality product can be obtained by vacuum evaporation only once from raw materials with the lower content of impurities whereas it is not for high content of impurities in raw material. This is due to the vapor-liquid equilibrium in the vacuum furnace. The impurities can be removed effectively by vacuum evaporation many times.
Authors: Ke Qiang Xie, Zhan Liang Yu, Wen Hui Ma, Yang Zhou, Yong Nian Dai
Abstract: In this paper, removal of iron from metallurgical grade silicon with pressure leaching is carried out. We investigated the factors such as the concentration of hydrochloric, particle size of raw material ground, temperature, pressure and reaction time, which influenced on the removal of iron. The results show that the optimum operating conditions for pressure leaching in hydrochloride are: acid concentration 4 mol/L, diameter for raw material less than 50 μm, leaching temperature 160 0C,leaching pressure 2.0 MPa, leaching time 2.0 h. The content of iron residual in MG-Si powder was reduced to about 200 ppmw. The removal efficiency of iron is up to 90.90 %.
Authors: Ke Qiang Xie, Jian Wen Tang, Xiu Min Chen, Wen Hui Ma, Bin Yang, Zi Li Liu
Abstract: Ab initio molecular dynamics (MD) calculations had been performed in this work to simulate the interactions of B with Fe, Al or Ca in metallurgical-grade silicon (MG-Si). The temperature of the MD simulations is 0K, the simulation time is 1ps. All the calculations were performed by using the CASTEP module of Materials Studio 4.3 software package. The geometry optimizations of impurities B with Fe, Al and Ca in MG-Si were performed with density functional theory (DFT) calculation. The Density of States of the optimized structures was calculated and the results have the potential application in guiding the boron removal from MG-Si by acid leaching.
Authors: Zi Liang Liu, Ke Qiang Xie, Wen Hui Ma, Yang Zhou, Yi Wang
Abstract: Coal fly ash (CFA), as a major solid waste of coal-fired power plants in China, is widely applied in building materials, pavement, and soil improvement. However, its potential value hasn’t been fully utilized yet. In recent years, CFA has received attractive attention as a potential raw material to prepare Al-Si alloy because of the main components of SiO2, Al2O3 and a small amount of iron in it. The presence of iron in CFA will benefit the process of carbothermic reduction which can be carried out at lower temperature for preparing Al-Si alloys. On the other hand, the content of iron in the Al-Si alloys products need to be controlled strictly, otherwise it will have the significant influence on the mechanical properties of the alloys and lead to the formation of excessive shrinkage defects. In this paper, we studied the necessity for deironing from Al-Si alloys prepared by CFA via hydrometallurgy pretreatment. Results indicate that the optimal route to prepare the qualified Al-Si alloys products is to remove most of the iron from CFA using hydrometallurgical pretreatment before carbothermic reduction. Other pyrometallurgy refining methods are applied to further deironing if necessary after the primary Al-Si alloys are obtained.
Authors: Ming Ming Li, Wen Jie Zhu, Wen Hui Ma, Yang Zhou, Ke Qiang Xie
Abstract: The high-quality MCM-41 was synthesized from silica fume with Citric acid and cetyltrimethylammonium bromide (CTAB) as template agents. Silica fume entered into liquid system in silicate and matched with CTA+. Mesoporous phase formed with the help of Citric and PEG-6000 in an acidic process followed. The structure and morphology of mesoporous silica material so-prepared was investigated based on the analysis of X-ray diffraction (XRD), N2 sorption/desorption (BET) and transmission electron microscopy (TEM). The results indicated that MCM-41 was successfully prepared by substituting silica fume for the traditional silica source of tetraethyl orthosilicate, and the MCM-41 displayed high quality with the pore sizes 4.3 nm, the BET areas 1058 m2/g, the total pore volume 0.862 cm3/g.
Authors: Zhe Ning, Ke Qiang Xie, Wen Hui Ma, Kui Xian Wei, Yang Zhou, Yang Yang
Abstract: The high ash coke breeze was leaching by two-stage chemical leaching. X-ray diffraction (XRD) and X-Ray Fluorescence (XRF) were employed to characterize the mineral phase and the element content respectably. More than 80% ash has been removed from the coke breeze by two-stage leaching. The removal of Si and Al was significantly affected by the temperature of alkali leaching. The mineral phase of the result coke breeze is similar to that of the raw ash except with cristobalite and sodium mica.
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