dissolution

In this paper, the dissolution kinetics of cement copper powder in sulfuric acid solutions containing cupric ions was examined. It was observed that the dissolution rate of copper increased with increasing the acid concentration, temperature, and stirring speed. It was determined that the dissolution rate of copper enhanced with increasing the cupric ion concentration up to 0.025 M. It was found that the temperature and concentration of cupric ion had more considerable effects on the dissolution of copper powder.

The dissolution process of potassium chloride particles in the apparatus with two-blade mechanical stirrer was investigated and the mass transfer coefficient was determined. The experimental results were generalized by criterion dependence. The independence of the mass transfer coefficient from the solid particles diameter was confirmed. A countercurrent process of potassium salt dissolution in two apparatuses with a mechanical stirring was considered. A mathematical model for countercurrent dissolution was developed and the efficiency of this process was determined.

The experimental investigation of the solubility of the prolonged-action nitroamophos obtained with the use of modified polyethylene terephthalate (PET) waste is presented. The kinetic coefficients of the diffusion process of the substances inside the shell are determined. The possibility of applying a theoretical model to predict the agro-ecological properties of encapsulated ammonium nitrate phosphate is demonstrated.

The study of the extraction process of the target components contained in the layer of grain material is presented. The process concerns the dissolution of solids from the outer surface of the solids and the extraction of the dissolved material from the layer of inert grain material in the stationary layer.

The technological and economic evaluation of two processes of langbeinite concentrate processing in a conditioned fertilizer was carried out with using mineral acids (nitric and phosphatic acid) for its dissolution. The first process allows to obtain non-chloride fertilizer (potassium-magnesium), and the second one allows to obtain not only potassium-magnesium, but such complex nitrogen-phosphorus fertilizer as diammophos.

The dissolution kinetics of potassium sulfate dissolved in water under pneumatic mixing has been investigated. The mass transfer coefficients were determined by the experiments, as well as on the basis of the local isotropic turbulence theory. The ratio between theoretical and experimental data was found to be satisfying that allows to determine the theoretical mass transfer coefficient to calculate the mentioned process.