Precipitation Characteristics of Crystallization Fouling on Metal Surface from 0.5mmol/l CaCO<sub>3</sub> Solution at 35°C

Abstract

The comparative experiments on CaCO3 crystallization fouling on brass, copper and stainless steel 304 and 316 at different pH at 35°C were carried out. The growing curves of fouling were got by direct weighing after static reaction experiments, and the morphology of crystals at different conditions was obtained by scanning electron microscope (SEM) and the parameters such as polymorphism, crystal size and so on were got, so the growing characteristics of CaCO3 crystallization fouling were known. The experimental results show the mass of crystallization fouling on stainless steeSubscript textl surfaces are almost equal and increasing a little when pH increased, but the mass of fouling on brass and copper surfaces are close and far less than on stainless steel and increasing a lot when pH increased; not only the homogeneous nucleation rate in bulk solution and heterogeneous nucleation rate on metal surface are increased to generate more new crystal nuclear but also square aragonite and calcite are formed more by higher pH, so the mass of metal surfaces is more and the phenomenon is more obvious that single crystal has a size extremum by higher pH.