Hard Water and Water Scale Formation :
Rain water always contents carbon dioxide (CO2) in small concentrations, which is absorbed from air . Such water is then able to dissolve calcium carbonate (CaCO3) while is in contact with rock material and calcium bicarbonate is formed:
CaCO3 + H20 + CO2 ------ Ca2+ + 2HCO3-
Water with higher content of alkali earth (Ca, Mg) (bi)carbonates is called as hard water . Using of hard water bring some technical problems indeed. Thus calcium carbonate based water scale formation is very hard complication of hard water using. The scale formation is caused by precipitation of calcium carbonate from solution. Calcium bicarbonate dissolved in water is decomposed to carbon dioxide and calcium carbonate by treatment of higher temperature or by water saturation with air. In these cases the calcium carbonate is for the most part precipitated in its calcite form. This modification is liable to deposit in form of scale on water contacted surfaces.
Ca(HCO3)2 ----- CaCO3+CO2+H2O
Hard Water :
Hard water is water with high in mineral contents like calcium and magnesium carbonates, bicarbonates and sulfates.
Water Scaling Deposition :
Deposition of minerals present in the (Hard Water)water on production system, Bathroom tiles, pipe system ,etc. is called water scaling deposition.