[01] B. P. Ravi, Mineral Processing Department, VSKU PG Centre, Nandihalli Sandur, Karnataka State, India. [02] M. R. Patil, Mineral Processing Department, VSKU PG Centre, Nandihalli Sandur, Karnataka State, India. [03] M. V. Rudramuniyappa, Mineral Processing Department, VSKU PG Centre, Nandihalli Sandur, Karnataka State, India. [04] G. Viswanath, Mineral Processing Department, VSKU PG Centre, Nandihalli Sandur, Karnataka State, India. [05] M. D. Khandali, Mineral Processing Department, VSKU PG Centre, Nandihalli Sandur, Karnataka State, India.

The objective of the investigation was to carryout flotation studies on fly ash sample analyzing 26.62 % LOI. 19.92% FC, 67.17 % ash and 2.17 % Moisture, containing mainly silicates and carbonaceous matter with subordinate to minor amounts of iron oxides and alumina minerals, to separate carbon from fly ash, with the non float fly ash concentrate assaying 5% max. fixed carbon (F.C.)/ 7% max LOI focusing on reagent consumption reduction from present 10kg/t 1:1:1mix of LDO, Kerosene and MIBC to as low dosage as possible. Flotation test on – 100 Mesh size ground fly ash sample [D80 100 microns] at29% Solids with 2 stages of cleaning by reverse flotation using1.5 kg/ t LDO as collector and 1.5 kg/t MIBC as frother, yielded a II cleaner carbon float assaying 51.9% LOI with 86% LOI recovery at wt % Yield of 51.3 which can be reused as fuel , while the composite ash concentrate [ Non float] assaying 6.62% LOI, and 4.25 %FC with 14% LOI recovery at wt % yield of 48.7 meeting the specifications. Dewatering studies [1] on carbon float yielded unit thickener area of 0.16m2/t/day at 0.4 kg/t SUFFLOC–A 1155 [2] on non float ash concentrate yielded unit thickener area of 0.26m2/t/day at 1.5 kg/t SUFFLOC – A 1155. The pressure filtration studies at 50% solids on both concentrate and tails thickened pulps yielded cakes of 18% moisture with 0.5t/h/m2. The work index of the sample was 9 Kwh/short ton. The sample is amenable to processing as the non float may be used in concrete block pavement industries and the float may be re used back after cleaner flotation in columns to reduce ash content. The evolved process mitigates the problem of vexed disposal of fly ash by reprocessing reusing and recycling besides, reducing reagent consumption during processing. The bulk concentrate produced was found suitable for tile-brick manufacture after evaluation.

Fly Ash, Flotation, LDO and Optimisation of Fly Ash Process

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