Document Type : Original Research Paper
Authors
1 Department of mining engineering, Arak university of technology, Arak, Iran.
2 Mineral Processing Research and Development, Golgohar Mining and Industrial Company, Sirjan, Kerman, Iran
3 Department of Mineral Processing, Tarbiat Modares University, Tehran, Iran
4 Department of Mining Engineering, Arak University of Technology, Markazi, Iran
Abstract
The main objective of the present study is to evaluate the feasibility of using gravity separation methods, including heavy bromoform liquid, spiral, and shaking table, for the primary concentration of gold from low-grade Siah Jangal ore (Sistan and Baluchistan Province, Iran). Characterization studies indicated that gold is mainly present as inclusions or within the lattice of pyrite and siderite minerals. For this reason, the potential of gravity separation methods using bromoform heavy liquid with a density of 2.89 g/cm³ was initially investigated in three size fractions: +1180, -1180+500, and -500 µm, where the maximum grade of 2.78 g/t with a recovery of 76.7% was obtained. The results showed that in coarser size ranges, both the grade and recovery of gold decreased. In spiral tests, the highest grade and recovery of gold were 2.33 g/t and 62.58%, respectively. The results of the shaking table experiments showed that, given a concentrate-to-feed weight ratio of 12%, a grade of 2.54 g/t could be achieved with a recovery of 73.81%, which, by eliminating a significant amount of tailings (about 88% of the feed), significantly reduces the operating expenses of subsequent processes (including flotation, oxidation, and leaching). It can be concluded that gravity methods, especially the shaking table, can serve as low-risk, low-cost, and environmentally friendly approaches for concentrating low-grade gold ores.
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