M Kor - faculty of mining ,petroleum and Geophysics,shahrood university of technology;shahrood.Iran
E Abkhoshk - islamic azad university,research and science campus , tehran,Iran
Kh Gharibie - faculty of mining ,petroleum and Geophysics,shahrood university of technology;shahrood.Iran
S.Z shafaei - faculty of mining ,petroleum and Geophysics,shahrood university of technology;shahrood.Iran

An attempt has been made in this paper to investigate the effect of particle size distribution on coal flotation kinetics.the effect of particle size (Ps) on kinetics constant (K) and maximum theopetical flotation recovery (RI) was investigated while other operational parameters were kept constant.the relationship between flotation kinetics constant and theoretical flotation recovery with particle size was estimated with ninlinear equations.Analysis of variance showed taht the effect of particle size on the kinetics constant was statistically significant at 95% confidence level.However ,it was not significant on maximum theoretical flotation recovery (RI).different regression methods were conducted in order to model the effect of coal particle size on flotation kinetics.results indicated taht the quadric regression method gave better prediction of the cummulative recovery for different particle size fractions.the correlation coefficient (R2) values of this model were 0.99,0.996,0.98,0.98 and 0.97 for average of particle size of 37.5 Mm , 112.5 Mm,225Mm,400Mm and 625 Mm respectively.

caoal flotation,particle size,flotation kinetics,multivariable regression