Calcium carbonate scale formation and control

This paper focuses on the complex problem of calcium carbonate scale formation on heated surfaces and the possibilities of controlling or reducing this problem. The development of scale is a multistage process and is affected by a number of factors, these include supersaturation, pH, temperature and flow velocity. Calcium carbonate deposition can be ameliorated by chemical, physical or biological methods with various level of effectiveness. These controls can be divided into three main categories: those that affect solubility, those that alter the growth mechanism of crystals, and those that change the potential of a surface to foul. One of the most effective methods of controlling crystallization fouling is the addition of chemical inhibitors to potentially scaling waters. There are a number of alternative non-chemical treatment options available, amongst these are the use of magnetic, electronic and electrolytic treatment devices. Scale formation is affected by the physical nature of the material on which it is forming, therefore it is possible to choose material to reduce scale formation. Each of these scale controlling methods has their advantages and a number of factors have to be considered before choosing the right option.