DETERMINATION OF WORK INDEX OF FAYACLAY TOWARDS EFFECTIVE COMMUNITION

Abstract

The work index of Faya clay ore in Faya Village, Plateau State, Nigeria was determined for effective communition design using Berry and Bruce method. Samples of bentonite ore were collected from three veins. The samples were homogenized, crushed and ground and further sampled using conning and quartering to obtain 5 kg representative fraction of the ore. 1kg was used for compositional study while 4 kg for laboratory work. Azara barite from Nassarawa State, with work index 6.24 kwh/ton was used as the reference ore sample. The studied Faya clay and reference ore samples were subjected to particle size analysis under the same condition. The chemical analysis of test sample (Faya clay) shows that it contains 35.6% SiO2, 16.6% Al2O3, 0.559% K2O, 0.084% CaO, 6.133% Fe2O3, 0.912% TiO2 and 38.7% BaO. The mineralogical analysis of Faya clay was determined by the use of the X-ray diffraction (XRD) analysis. The major mineral phases in the ore sample are; 61.7% wt. quartz (SiO2) 28.59% wt. dickite (Al2 Si2O5 (OH)), 8.89% wt. geothite (FeO (OH)4) and 0.83% wt. muscovite (K0.92 Na0.08) (Al1.86 Fe0.07 Ti0.02) (Si3.03 Al0.97) 010(OH)2. The result of the particle size analyses of the mill feeds and products of milling further indicated that the mesh of grinds from the semi-log plots were 180 μm and 125 μm for the test sample; while 250 μm and 180 μm for the reference sample. The result of the particle size analyses was validated by calculation using the Guadin- schuhman logarithm equation. The value of the work index of the test sample (Faya clay) was found to be 4.83 kwh/ton. It can therefore be concluded that 4.83 kwh/ton is the energy required for Faya clay to be comminuted from an infinite size to 80% passing 100 μm sieve size.