Browsing by Author "Kobatake, Hidekazu"

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    Effect Of Aluminum Carbide Additives On Carbothermic Reduction Process From Alumina To Aluminum
    (Oum-El-Bouaghi University, 2018) Chahtou, Amina; Benioub, Rabie; Boucetta, Abderahmane; Zenga, Lihaowen; Kobatake, Hidekazu; Itaka, Kenji
    In terms of electricity consumption, the carbothermic reduction process of alumina (Al2O3) represents one of the promising candidates to overcome the current industrial Hall-Héroult process for the production of aluminum (Al) from Al2O3. The yield of the carbothermic reduction process of Al2O3, however, is not high enough to be considered as a substitute for the present industrial process. The calculation of the gas phase diagram of Al-O-C system suggests the possibility of the enhancement of the Al product yield by the increase of the ratio of the partial pressure Al2O/CO. An increase in the ratio of the partial pressure Al2O/CO can be expected by the reaction of aluminum carbide (Al4C3) and Al2O3. We investigated the effect of adding Al4C3 on the enhancement of the final Al yield in the production process. In the case without Al4C3 additive, the Al yield was only 1.4 %, while, in the case of adding Al4C3 additive with Al2O3: Al4C3 = 1:0.05 in molar ratio, the Al yield increased drastically up to 21.3 %.
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    Optimization Of The Raw Material Input Molar Ratio On The Carbothermal Production Of Solar-grade Silicon
    (Oum-El-Bouaghi University, 2017) Benioub, Rabie; Adnane, Mohamed; Boucetta, Abderahmane; Chahtou, Amina; Kobatake, Hidekazu; Furuya, Yasubumi; Itaka, Kenji
    With the fast growth of solar cells market, it is strongly required to improve the fabrication process of solar-grade silicon, which is the base material for more than 93% of solar cells technology. Conventionally, solar-grade silicon is produced via the direct reduction of silica stone to metal-grade silicon by arc furnace followed by the Siemens method with chemical treatment and hydrogen. However, in this technique, a low yield of solar-grade silicon is obtained with high energy cost due to its multiple complex processes. Meanwhile, it has been turned out that, the direct reduction process from silica sand to solar-grade silicon via induction furnace simplify the fabrication process with low energy and cost consumption with higher yield. In this study, the optimum partial pressure and temperature conditions of this process were based on the stability phase diagram for reduction reaction process. Using the simulation results, we succeeded to increase the reduction yield by ten times.