Browsing by Author "Engin, VT"

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    Technical and economical applicability study of centrifugal force gravity separator (MGS) to Kef chromite concentration plant
    Çiçek, T; Cöcen, I; Engin, VT; Cengizler, H; Sen, S
    The results of multigravity separator (MGS) upgrading tests on fine chromite gravity tailings using -100 and -100+150 mu m fractions of the initial sample (-1 mm) with 24.7% Cr2O3 grade were presented. The metal screen analysis revealed that 20.66% of the total Cr2O3 content was present in the -106 mu m size fraction. Under optimal operational conditions, a concentrate with 43.7% Cr2O3 content and 65.0% chromite yield for the size fraction of -100 mu m and a concentrate with 30.5% Cr2O3 and 83.3% yield for the size fraction of -100+150 mu m could be produced. Shaking table test results revealed that the coarse fraction of the tailings could not be enriched any further owing to the high concentration of interlocked particles. However, a saleable concentrate could be obtained by MGS when the coarse tailings were ground down to -100 mu m and used as the feed. The results of the study suggested that multigravity separation of the Kef tailings was technically feasible and economically viable. The payback time of two alternatives suggested for the utilisation of MGS in Kef concentrator was calculated to be <7 months.
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    An efficient process for recovery of fine coal from tailings of coal washing plants
    Çiçek, T; Cöcen, I; Engin, VT; Cengizler, H
    Gravity concentration of hard lignites using conventional jigs and heavy media separation equipment is prone to produce coal-rich fine tailings. This study aims to establish a fine coal recovery process of very high efficiency at reasonable capital investment and operational costs. The technical feasibility to upgrade the properties of the predeslimed fine refuse of a lignite washing plant with 35.9% ash content was investigated by employing gravity separation methods. The laboratory tests carried out with the combination of shaking table and Mozley multi-gravity separator (MGS) revealed that the clean coal with 18% ash content on dry basis could be obtained with 58.9% clean coal recovery by the shaking table stage and 4.1% clean coal recovery by MGS stage, totaling to the sum of 63.0% clean coal recovery from a predeslimed feed. The combustible recovery and the organic efficiency of the shaking table + MGS combination were 79.5% and 95.5%, respectively. Based on the results of the study, a flow sheet of a high-efficiency fine coal recovery process was proposed, which is also applicable to the coal refuse pond slurry of a lignite washing plant.