The influence of pipe geometry on scale growth rate for a super-saturated caustic-aluminate solution

Scale growth in alumina refineries occurs where supersaturated solutions come in contact with solid surfaces. Whilst some scale formations may prove beneficial in protecting equipment and pipe surfaces from chemical attack or abrasion, more commonly its deposition results in reduced equipment performance and plant productivity. It is estimated that the direct cost of scale removal may contribute as much as one quarter of the operational costs of an alumina refinery. The rate of scale growth in pipe work, consisting of straight pipes connected by reducers (contractions) located in the precipitation area of an alumina refinery, is approximately 60% higher in the reducers than it is in the straight pipes.