Corresponding author:Serhii Haidai E-mail: GaidaiSS@i.ua DOI: 10.24263/2304-974X-2016-5-4-16 Introduction. The objective of this work is mathematical modeling of inhomogeneous hydrodynamic regime of fluidization, which will improve the efficiency of heat and mass transfer in processes of obtaining organic-mineral fertilizers, which include sunflower ash, stimulating and nutritional components.Materials and methods. The process of inhomogeneous fluidization, which causes an active volumetric mixing of granular material with the intensive circulation in bed, was held in camera of granulator, equipped with a special gas distribution device in the bottom and the directing insertion in the upper part. Measurements of pressure drop in the bed and videofixation of hydrodynamics have been done by using the special equipment.Results and discussion. An inhomogeneous regime of fluidization is implemented with applying the original gas-distributing device (with a factor of cross-section φ=4.9%) and the improved chamber of granulator. An intensive macro-mixing of a granular material (with an equivalent diameter D e =3.97 mm and density ρ p =1450 kg/m 3 ) is provided with ratio of nominal pressure drop to height of layer -ΔP b /H 0 ≥8500 Pa/m and frequency of pulsations f=1.67 Hz. The absence of stagnant zones provides the coefficient of granule formation ψ≥90%, and the average specific load of bed's surface by moisture a f =0.8÷0.9 kg wet /(m 2 ·h). A chosen mathematical model was modified what allowed to define the conditions of the process considering inhomogeneity in which 25% of the layer mass is in active phase above the bed with a frequency f=1.67 Hz. It confirms the results of research with accuracy of 94.8%.Conclusions. Hydrodynamics without formation of stagnant zones in chamber of granulator was implemented. Modified mathematical model allowed to determine the intensity of an active volumetric circulating mixing that will significantly improve the stability of a granule formation process in dewatering of liquid heterogenous systems.