Carbothermic reduction of alumina with carbon in vacuum

Abstract

Carbothermic reduction alumina in vacuum was conducted, and the products were analysed by means of XRD and gas chromatography. Thermodynamic analysis shows that in vacuum the initial carbothermic reduction reaction temperature reduces compared with that under normal pressure, and the preferential order of products is Al₄O₄C, Al₄C₃, Al₂OC, Al₂O and Al. Experiment results show that the carbothermic reduction products of alumina are Al₄O₄C and Al₄C₃, and neither Al₂OC, Al₂O or Al was found. During the carbothermic reduction process, the reaction rate of Al₂O₃ and carbon decreases gradually with increasing time. Meanwhile, lower system pressure or higher temperature is beneficial to the carbothermic reduction of alumina process. Al₄O₄C is firstly formed in the carbothermic reaction, and then Al₄C₃ is formed in lower system pressure or at higher temperature.

Keywords

alumina / carbothermic reduction / vacuum / aluminum

References

[1] KaiG., HalvorK., LiQ.-f., QiuZ.-xian.Metal production by molten salt electrolysis especially aluminum and magnesium [M], 1998BeijingChina University of Mining and Technology Press73-75

[2] SteinfeldA., ThompsonG.. Solar combined thermochemical processes for CO₂ mitigation in the iron, cement, and syngas industries [J]. Energy, 1994, 19(10): 1077-1081

[3] LiJ., FangZ., LaiY.-q., LüX.-j., TianZ.-lian.. Electrolysis expansion performance of semigraphitic cathode in [K₃AlF₆/Na₃AlF₆]-AlF₃-Al₂O₃ bath system [J]. Journal of Central South University of Technology, 2009, 16: 422-428

[4] MYKLEBUST H, RUNDE P. Greenhouse gas emission from aluminum carbothermic technology compared to Hall-Héroult technology [J]. Light Metals, 2005: 519-522.

[5] CHOATE W, GREEN J. Technoeconomic assessment of the carbothermic reduction process for aluminum production [J]. Light Metals, 2006: 445-450.

[6] WANG Ping-yan, DAI Yong-nian, JIANG Shi-xin, ZHONG Hong-quan. Study on production of aluminum by carbothermic reduction and subhalide decomposition under vacuum [J]. Nonferrous Metals (Metallurgy), 2005(2): 11–13. (in Chinese)

[7] JeanP. M.. Aluminum production using high temperature solar process heat [J]. Solar Energy, 1999, 66(2): 133-142

[8] FabiolaJ. A., AnaE. B.. Direct chlorination of nickel-containing materials. Recovery of the metal from different sources [J]. Industry Engineering Chemistry Research, 2008, 47: 8184-8191

[9] YangF., HlavacekV.. Carbochlorination of tantalum and niobium oxides, Thermodynamic simulation and kinetic modeling [J]. Journal of AIChE, 1999, 45: 581-589

[10] WangP.-y., YangB.-z., DaiY.-n., LiuY.-cheng.. Test equipment for the production of aluminum by carbothermic reduction of aluminum-bearing materials with the aid of subhalide decomposition under vacuum [J]. Mining and Metallurgical Engineering, 2005, 25(2): 43-45

[11] MattigodS. V., McgrailB. P.. Estimating the standard free energy of formation of zeolites using the polymer model [J]. Microporous and Mesoporous Materials, 1999, 27: 41-47

[12] AlbertyR. A.. Use of standard Gibbs free energies and standard enthalpies of adenosine(aq) and adenine(aq) in the thermodynamics of enzyme-catalyzed reactions [J]. Journal of Chemistry Thermodynamics, 2004, 36: 593-601

[13] ChoyK. L.. Chemical vapour deposition of coatings [J]. Progress of Material Science, 2003, 48: 57-170

[14] LihrmannJ. M.. Thermodynamic of the Al₂O₃-Al₄C₃ system I. Thermochemical functions of Al oxide, carbide and oxycarbides between 298 and 2 100 K [J]. Journal of the European Ceramic Society, 2008, 28: 633-642

[15] ChaseM. W.NIST-JANAF thermochemical tables [M], 19984th EdNew YorkAmerican Chemical Society and the American Institute of Physics for the National Institute of Standards and Technology98-143

[16] HalmannM., FreiA., SteinfeldA.. Carbothermal reduction of alumina: Thermochemical equilibrium calculations and experimental investigation [J]. Energy, 2007, 32: 2420-2427

[17] MiaoC.-sheng.X-ray quantitative analysis method and its application [M], 1988BeijingGeography Press10-20

[18] QiuZ.-xian.Physical chemistry of aluminum metallurgy [M], 1985ShanghaiShanghai Science and Technology Press340-360

[19] FolomeikinY. K., DemonisI. M., KablovE. N., LopatinS. I., StolyarovaV. L.. Investigation into the Vaporization of Al₂O₃ in the Presence of Carbon at High Temperatures [J]. Glass Physics and Chemistry, 2006, 32(2): 191-195