Sulfidation Kinetics of Natural Chromite Ore Using H 2 S Gas
- PDF / 1,842,601 Bytes
- 11 Pages / 593.972 x 792 pts Page_size
- 37 Downloads / 162 Views
ION
ILMENITE (FeTiO3) and associated high-TiO2 alteration products such as leucoxene and pseudorutile are feedstocks for the production of TiO2 pigment using either the sulfate or chloride processes. The presence of chromium in the TiO2-rich concentrates, most often occurring within the spinel group of minerals (e.g. chromite FeCr2O4), has a detrimental effect on the color of the normally bright white TiO2 pigment, and needs to be removed before processing.[1] The common practice to separate chromite from the ilmenite is through a magnetizing roast pre-treatment followed by magnetic separation. Ilmenite and chromite exhibit overlapping physical properties (magnetic, conductivity, specific gravity) and the magnetizing roast causes the ilmenite to change its magnetic properties while the chromite properties remain essentially unchanged.[2] This then allows the removal of chromite from ilmenite using magnetic separation. However, in situations where there is an extended range in overlapping physical properties, due to factors such as extreme chemical weathering of the ilmenite concentrate or multiple sources for chromite contamination, a magnetizing roast approach cannot always be implemented as clear separation is more
SAZZAD AHMAD, Ph.D. Candidate, is with the Department of Mechanical and Product Design, Swinburne University of Technology, Melbourne, VIC 3122, Australia, and also with the CSIRO Minerals Resources Flagship, Bayview Avenue, Clayton, VIC 3168, Australia. Contact e-mail: [email protected] M. AKBAR RHAMDHANI, Associate Professor, is with Department of Mechanical and Product Design, Swinburne University of Technology. MARK I. POWNCEBY, Principal Research Scientist, and WARREN J. BRUCKARD, Research Operations Manager, are with the CSIRO, Mineral Resources Flagship. Manuscript submitted August 15, 2014. METALLURGICAL AND MATERIALS TRANSACTIONS B
difficult.[3,4] The variability in both ilmenite and spinel compositions means that magnetically tight populations are not always achieved. This is the case with ilmenite deposits from the Murray Basin region in southeastern Australia where prolonged weathering has resulted in broad compositional variation in the ilmenite grains through oxidation, hydration, and leaching of iron and manganese.[5] Significant Cr, Fe, Mg, Al, and Ti compositional variation is present in associated spinel grains due to transport from multiple source regions.[6] There are a number of previous studies that focus on finding a feasible solution to separate the chromebearing spinel impurities from the Murray Basin ilmenite concentrates.[7,8] Fisher-White et al.[7] carried out a low temperature roasting at temperatures between 848 K and 1123 K (575 C and 850 C). They achieved 78 to 86 pct ilmenite recovery but found that the reaction conditions were sensitive to rutile (TiO2) formation and crystallization. The formation of crystalline rutile is unwanted for the sulfate-route pigment production process. They also observed that the same reaction conditions, applied to an ilmenite concentrate fro
Data Loading...
