engleski

Fluid-bed granulation of dolomite

Agrochemical substance, dolomite was formulated in fluid-bed granulation process. In this work, the effect of the liquid-to-solid ratio and rate of binder addition on the granule size distribution (GSD) have been investigated. Mechanistic approach to process integrates application of a discretised population balance model (Hounslow et al., 1988) and the size independent kernel model (Kapur and Fuerstenau, 1969). Integral method was used for coalescence rate parameter estimation. Dolomite powder was granulated in a laboratory, batch process unit with a three component binder formulation, water-molasses-polyvinylpyrrolidone. Experiments were performed in a top-spray mode. GSD was determined by sieving and displayed as a normalised mass density function. Series of experiments were repeated at the identical process conditions in order to investigate reproducibility of the granulation experiments. Derived monomodal GSD's are evidently influenced by liquid-to-solid ratio and rate of binder addition. Model predictions using the size independent kernel indicate the presence of the preferential coalescence growth regime. Generated kinetic considerations represent a valuable step towards comprehensive perspective of dolomite granulation.

Fluid-bed granulation; Dolomite; Granule size distribution; Population balance

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