Impact of solution hydrodynamics on the deposition of CaSO₄ on brass

An investigation was conducted to study the impact of solution hydrodynamics on the deposition of calcium sulfate scale on commercial brass by using a rotating cylinder electrode system at various pre-set rotational speeds, at 60 and 70°C on 120 and 600 grits polished cylindrical specimens. The effects of temperature, surface roughness, and flow conditions on the deposition of calcium sulfate scale on brass are presented. The results indicate the influence of solution hydrodynamics on the rate of calcium sulfate scale deposition on brass specimens by delineating the competing effect between the scale deposition and scale removal process that is occurring simultaneously under the fluid flow conditions generated in the study. The morphology of deposited crystals was obtained from scanning electron microscope (SEM) micrographs and composition was determined with energy dispersive X-ray spectrometer (EDS) method. The SEM analysis revealed prismatic needle- and rod-like crystals growth structure at nucleation sites branching out randomly over the substrate. The secondary growth on the already existing primary crystals of CaSO₄ was also noticed. The EDS analysis confirmed the composition of crystals comprising of Ca, S, and O as expected because of the purity of chemicals used.