Thermodynamics Calculation and Experimental Study on Separation of Bismuth from a Bismuth Glance Concentrate Through a L
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A is the largest producer of bismuth in the world. Current estimates place the bismuth output of China at more than 60 pct of the total global output.[1] Bismuth deposits are found in Hunan,Guangxi, and in many other provinces throughout China; of these, Hunan has the richest deposits. In particular, Shizhuyuan, near Chenzhou City, has been celebrated for a long time for the quality and quantity of its bismuth.[2–4] The commercial route to extract bismuth from its sulfide mineral bismuth glance at Shizhuyuan Nonferrous Co. Ltd. (Chenzhou, Hunan Province), is a pyrochemical process (more than 1473 K (1200 C), which involves reducing the bismuth sulfide to a metallic bismuth in reverberatory furnaces and recovering valuable associated metals such as molybdenum and tungsten from slag via a hydrometallurgy process.[5] However, smelting bismuth under this high smelting temperature causes two serious problems in the form of JIAN-GUANG YANG and MO-TANG TANG, Professors, DE-WEN HE, CHAO-BO TANG, YONG-MING CHEN, Associated Professors, and YA-HUI SUN, Undergraduate, are with the Department of Metallurgical Science and Engineering, Central South University, Changsha 410083, P.R. China, and with the Post-doctoral Scientific Research Center of Guanxi Tanghan Zinc & Indium Co., Ltd., Nandan 547200, P.R. China. Contact e-mail: jianguang_yang@ hotmail.com Manuscript submitted December 9, 2010. Article published online April 14, 2011. 730—VOLUME 42B, AUGUST 2011
serious environmental pollution and large energy consumption. A. Serious Environmental Pollution During the pyrochemical smelting process, considerable quantities of associated large-vaporization-pressure metals, such as lead, arsenic, and cadmium, together with low concentrations of SO2 are emitted as a result of volatilization. At present, the smelting of nearly all nonferrous metals has overcome the problem of low concentrations of SO2 emission by adopting an enhanced oxygen-rich smelting technology such as the Ausmelt process, Noranda process, Mitsubishi process, and so on. However, because it is a comparatively small industry, it is not economical to apply the enhanced, oxygen-rich smelting technology to bismuth smelting. Therefore, large numbers of low-concentration SO2, together with some escaped heavy metals, result in serious environmental pollution in the areas surrounding the bismuth smelting plants caused by the use of obsolete technology. In addition, beryllium is typically found within bismuth glance in the form of beryl (Be3Al2(SiO3)6). At these high smelting temperatures (>500 K [1227 C]), this compound can be decomposed and produce virulent BeO and other active beryllide. To date, not a single known method for bismuth recovery can ensure an adequate environmental control at the positions of the operator and in areas adjoining such bismuth-recovering enterprises.[6–10] METALLURGICAL AND MATERIALS TRANSACTIONS B
B. High-Energy Consumption To sustain this pyrochemical process (>1500 K [1227 C]), large quantities of high-quality coal are consumed. Currently, m
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