PHYSICAL SEPARATION PROCESSING OF A BULK TIN-TUNGSTEN PRE-CONCENTRATE INTO ITS INDIVIDUAL CONSTITUENTS FOR COMMERCIAL APPLICATIONS

摘要

The steel and most base-metal industries are currently experiencing low prices in the international market, due to a global economic recession that has resulted in low production. On the other hand, tin and tungsten metal prices are showing an upward trend, giving a scope to the processing of tin & tungsten ores for production of these metals, which will result in their higher prices, aside from maintaining their strategic importance. The mineral sectors in India have been opened to multi-national companies and to the international market, due to the liberalization of the mineral policies of the Indian Government. Likewise, outside opportunities have been opened for Indian mining companies, as well as international mining companies based in India (Indian Minerals Yearbook, 1997). Keeping these aspects in mind, an international mining company, based in India, with the intention to make a mining lease outside India, sponsored a beneficiation study for tin-tungsten bulk pre-concentrate in the modern mineral-processing laboratory of the Indian Bureau of Mines in Nagpur. The objective of the study was to separate the bulk pre-concentrate into two sellable components, one containing more than 40% Sn for tin smelting and the other one containing 44% WO_3 for producing ammonium para tungstate (APT). A combination of gravity, magnetic and electrostatic separation yielded a tin concentrate assaying 61.0% Sn with Sn recovery of 78% and a tungsten concentrate assaying 44.21% WO_3, with WO_3 recovery of 71.4%, meeting the stipulated chemical specifications, including the tolerance limit of impurities. This paper deals with the details of test work in developing a suitable beneficiation processing flowsheet, to produce individual concentrates of tin and tungsten for possible commercial application.