Selected Aspects of Fertilizer-Grade Magnesium Sulfate Crystallization from Solution after Flue Gas Desulfurization

The presented paper deals with the discussion concerning both technological and process aspects connected with the production of a magnesium sulfate fertilizer from a solution obtained as a result of a flue gas desulfurization by means of the magnesium method. The experimental research was carried out on a laboratory scale in the MgSO4–MgCl2–H2O system. The paper took into account: (i) the kinetics of MgSO4·7H2O crystallization, (ii) the relation between the efficiency and the particle size, (iii) the influence of MgCl2 concentration in the solution, and (iv) solution pH and its viscosity on the process. The degree of solution supersaturation discharge during crystallization was also analyzed. As a result, a number of practical conclusions regarding the process in industrial conditions were presented.