Engineering and Mining Journal - Whether the market is copper, gold, nickel, iron ore, lead/zinc, PGM, diamonds or other commodities, E&MJ takes the lead in projecting trends, following development and reporting on the most efficient operating pr
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MAY 2017 • E&MJ; 49 www.e-mj.com PROCESSING SOLUTIONS is treated by wet primary autogenous milling, LIMS (Low intensity magnet- ic separation) extraction of magnetite, WHIMS (Wet high-intensity magnetic separation/Jones-process) recovery and upgrading of hematite in combination with gravimetric methods, classifying, dewatering and storage of the fi nal prod- uct. The extracted magnetite is further treated to form high-purity concentrate by re-milling and subsequent multi- ple-step LIMS upgrading. Rio Tinto Seeks to Recover More Cu, Mo at Kennecott Operation Elsewhere, Eriez announced that recov- ery technology, including the patented HydroFloat technology from its Flotation Division (EFD), is being tested in a pilot plant jointly with Rio Tinto to evaluate the possibility of improving metals recovery at its Kennecott Copper (RTKC) operation near Salt Lake City. "RTKC's innovation and development portfolio has included projects to benefi t ore throughput and value recovery," noted David George-Kennedy, former director of the RTKC Innovation and Development Group. "HydroFloat is a technology of- fered by Eriez that has been successful- ly deployed at commercial scale in the phosphate and potash industries for over a decade. We think the concept has tre- mendous potential for RTKC." EFD and the RTKC Innovation and Development Group have jointly in- vestigated the applicability of the Hy- droFloat technology to ore containing valuable minerals that are not recovered conventionally at the RTKC Copperton concentrator. A study supported by a pilot facility supports the case that the HydroFloat is recovering up to 70% of coarse-particle copper and up to 90% of coarse-particle molybdenum that is not collected by conventional fl otation technology. Throughout its history, Kennecott Copper's Bingham Canyon mine has pro- duced more copper than any other US mine — more than 19 million tons, ac- cording to RTKC. Before testing the Hy- droFloat, RTKC was losing 10% of copper and 16% of moly to waste. The HydroFloat Separator is an aer- ated fl uidized-bed (or teeter-bed) sep- arator. The synergistic effect of combin- ing fl otation with gravity concentration results in an outcome that cannot be achieved by either approach alone, ac- cording to the company. Air bubbles, which are dispersed by the fl uidization system, percolate through the hindered-setting zone and attach to the hydrophobic component, altering its density and rendering it suf- fi ciently buoyant to fl oat and be recov- ered. The use of a dense phase, fl uidized bed eliminates axial mixing, increases coarse particle residence time and im- proves fl otation rate through enhanced bubble-particle interactions. As a result, the recovery rate is high for fully- and semi-liberated particles. Formerly known as Canadian Process Technologies, EFD is a wholly owned subsidiary of Eriez Manufacturing Co. EFD provides advanced testing and engineering services, in addition to sparging and column fl otation equip- ment for the mining and mineral pro- cessing industries. The results of testing the Refl ux system at a far-north iron ore operation showed that, while the ore grade of the feed to the classifi er was approximately 10% Fe, the concentrate produced by the Refl ux technology was more than 60% Fe, with a yield of more than 20% of the iron in the 0–150 µm size fraction that is currently lost to waste. At the Kennecott Copper operation, a study supported by a pilot facility indicates that Eriez EFD's HydroFloat tech- nology recovers up to 70% of coarse-particle copper and up to 90% of coarse-particle molybdenum that is not currently collected by conventional fl otation technology.