Advanced Materials Research Vol. 813

Abstract: A new model based on least square support vector machines (LSSVM) and capable of forecasting mechanical and electrical properties of Cu-15Ni-8Sn alloys has been proposed. Data mining and artificial intelligence techniques of copper alloys are used to examine the forecasting capability of the model. In order to improve predictive accuracy and generalization ability of LSSVM model, leave-one-out-cross-validation (LOOCV) technique is adopted to determine the optimal hyper-parameters of LSSVM automatically. The forecasting performance of the LSSVM model and the artificial neural network (ANN) has been compared with the experimental values. The result shows that the LSSVM model provides slightly better capability of generalized prediction compared to ANN. The present calculated results are consistent with the experimental values, which suggest that the proposed LSSVM model is feasible and efficient and is therefore considerd to be a promising alternative method to forecast the variation of the hardness and electrical conductivity with aging temperature and aging time.

Abstract: A new process was provided for decomposition of ilmenite by ammonium hydroxide under hydrothermal process. The significant effects of reaction temperature, NH₄OH concentration, NH₄OH-to-ilmenite mass ratios on titanium extraction were studied. The temperature showed significant influence on titanium extraction. The experimental data of the extraction rates under the relevant operating variables were well interpreted with the shrinking core model under chemically controlled process.

Abstract: The progress of the application of microwave pyrolysis in China and oversea is reviewed. Introduce the methods and mechanism of produce high value-added chemicals through microwave heating of biomass, sludge and fossil fuel. And there should non-thermal effect existing in the microwave pyrolysis, and is worth to explore a way for the efficient fast pyrolysis of resources utilization of validity.

Abstract: Precipitation phase and impurities distribution of MG-silicon were investigated by vacuum refining followed by slag treatment, and the CaO-SiO₂-CaF₂ system was adopted for slag treatment. Contrasting the microstructure of precipitated phase in slag treatment with and without vacuum refining pretreated, it could be concluded that the composition of precipitated phases, obtained in MG-Si after vacuum refining followed slag treatment, only consisted of Ca-rich intermetallic silicide phases such as Si-Ca-Ni, Si-Ca-Fe and main impurity phase Si-Ca. And the vacuum refining could make an increase in concentration of the impurity Ti due to its low saturated vapor pressure and silicon loss, which was in favor of the interaction with the impurity B, resulting in the formation of TiB₂ that could stay at the slag. Consequently, the vacuum refining could be regarded as an effective method for facilitating the removal of B from MG-Si with slag treatment.

Abstract: A new slag system, Y2O3-SiO2-CaF2 system, was adopted in purification of Si for photovoltaic application. The partition ratio of boron (LB) between slag and silicon was studied under different mass ratio of slag to silicon and varying basicity at 1873K. Scanning electron scope and electron probe micro analysis were used to detect the distribution of impurity elements in silicon after slag refining. The experimental results show that the mass ratio of slag to silicon did not affect the trend of slag basicity with LB, and high mass ratio of slag to silicon would decrease LB. Silicon was surrounded by amorphous slag. Impurity elements are concentrated in slag. Yttrium oxide’s role in slag and kinetic analysis of boron removal are also discussed.

Abstract: Porous mullite ceramics were prepared using an industrial grade mullite powder by foaming and starch consolidation method. The influence of solid loading of suspension and sintering temperature on the porosity of samples was evaluated. The sintered mullite ceramic with porosity from 73 to 86 vol% contained the microstructure with spherical pores and a larger mean pore size. Thermal conductivity measurements were carried out by the hot-disk technique at room temperature resulted in values as low as 0.09 W/(m·K).

Abstract: The purpose of the present study was to demonstrate the feasibility of adsorbent IRN77 resin for removal of Cr (III) from acid-dissolution water of chromium sludge. Extractions of Cr (III) from a model solution and a acid-dissolution water of chromium sludge were studied by IRN77 cation-exchange resin, respectively. The results suggested that extraction of Cr (III) with this resin followed the Lagergren first-order kinetics. The resin was high selective for Cr (III) sorption in the pH range 1-5 from a model solution containing 150 mg/L Cr (III), and a Cr (III) extraction above 99% was obtained. The studies further showed that 80% Cr (III) from a diluted acid-dissolution water containing about 150 mg/L Cr (III) could be removed which validated the process developed with model waste solution. At the same time, from the loaded resin 99% Cr (III) was eluted with 10% H₂SO₄. Therefore, this cation-exchange resin could be used as an efficient adsorbent material for the removal of chromium from acid-dissolution water of chromium sludge.

Abstract: The objective of this study was to increase flux and decomposition speed through the development of a multi-type electrical field decomposition facility that employs a more complex modulated electromagnetic field than that used in existing decomposition facilities where recalcitrant organics or heavy metals are combined together. Further, in this study, optimized foundational data was derived from the results obtained following field work. As a result, when an electrical field was applied to an electrolyzer, decomposition of the electrolyzer was carried out quickly, thereby showing higher efficiency because an electrical field was permeated to the contaminant faster compared to the case where an electrolyzer was not added. Keywords: Electromagnetic field, Heavy metal, Electrolyzer, Electrical field

Abstract: A purpose of the present study is to derive optimum study factors for removal of heavy metals using combined alternating current electric/magnetic field and electric membranes for the area contaminated with heavy metals in soil or underground water. ORP (Oxidation Reduction Potential) analysis was conducted to determine an intensity of tendency for oxidation or reduction of the samples contaminated with heavy metals, and electrical membrane treatment was used with adjustment of concentrations and voltages of liquid electrode (Na₂SO₄) to derive a high removal rate. Removal constants were analyzed to be 0.0417, 0.119, 0.1594 when the voltages were 5V, 10V, 15V, respectively, and treatment efficiency was shown to increase as the liquid electrode concentration was increased. Keywords: heavy metals, electric/magnetic field, ORP, electrical membrane