ISSN: 1003-6326
CN: 43-1239/TG
CODEN: TNMCEW

Vol. 27    No. 5    May 2017

Reducing and sulfur-fixing smelting of stibnite to produce antimony by one-step using iron materials as sulfur-fixing agent
XU Kang-ning1, CHEN Yong-ming2, WANG Yue-jun1, XUE Hao-tian2, YE Long-gang2, ZHANG Wen-bo1
(1. Science Department, Hetao College, Bayannur 015000, China;
2. School of Metallurgy and Environment, Central South University, Changsha 410083, China
)
Abstract: In the views of the shortcomings in the current antimony smelting process which are high energy consumption and a long flow, a new process was proposed to smelt antimony directly from stibnite by reducing and sulfur-fixing reaction in NaCl-Na2CO3 molten salt. The reaction mechanism of reductive sulfur-fixation process of Sb2S3 was investigated. The results show that, for Sb2S3-FeO-C system, Sb2O3 and FeS are generated by sulfur-fixation reaction between Sb2S3 and FeO. And then, Sb2O3 can be consecutively reduced to Sb by reductive agent. The influencing parameters during smelting process are comprehensively investigated, including sodium salt content and composition, ferric oxide dosage, smelting temperature and smelting time. The optimum conditions are determined as follows: =1.0, mC:mconcentrate=40%, smelting temperature of 850 ℃ and smelting time of 60 min. Under the optimal smelting conditions, the average direct recovery rate of antimony and grade of crude antimony are 91.48% and 94.31%,respectively. Comparing to the traditional pyro-metallurgical process, the smelting temperature of present process is reduced at least 300 ℃. And sulfur is fixed in the form of FeS in the smelting process, so low concentration of SO2 emission could be avoided completely.
Key words: antimony metallurgy; molten salt smelting; sulfur-fixing mechanism; ferric oxide slag
Superintended by The China Association for Science and Technology (CAST)
Sponsored by The Nonferrous Metals Society of China (NFSOC)
Managed by Central South University (CSU)