Influence of water hardness, substrate nature and temperature on heterogeneous calcium carbonate nucleation

We studied the effect of water hardness, temperature and the nature of walls on CaCO3 heterogeneous nucleation, which is the main condition of scale. The probability of CaCO3 heterogeneous precipitation increased for weak water hardness and weak temperatures. The wall nature did not influence the precipitation kinetics for hard water and high temperatures, but it had an important effect on the type of nucleation. The determination of the precipitate scale amount following heterogeneous nucleation by means of a weighted method showed that plastic materials have a greater scaling susceptibility than metallic materials.

The parameters influencing calcium carbonate precipitation, a major constituent of scale, remain difficult to master. We were interested in the effect of water hardness, temperature and the nature of cell walls on CaCO3 heterogeneous nucleation, which is the main condition of scale deposits. The present survey showed that the probability of CaCO3 heterogeneous precipitation was increased for weak water hardness, low supersaturations and low temperatures. The nature of the wall did not influence the precipitation kinetics for hard water or elevated temperatures. On the other hand, it had an important effect on nucleation and precipitation conditions. The determination of the precipitate quantity of scale following heterogeneous nucleation by means of a weighted method showed that plastic materials have a greater scaling affinity than metallic materials.