-Drinking Water and process
In both drinking and process water preparation, lime is mainly used for pH adjustment and/or water purification.
Milk of lime, among other products, is a cost-effective reagent which reduces the water's hardness by precipitating the bicarbonates dissolved in it, thus preventing the formation of scale.
Drinking water must be pure. The elimination of undesirable components such as organic matters and metallic trace elements with the aid of lime milk is an integral part of the water purification process.
Lime milk is also used for softening or remineralizing drinking waters
If the water is too soft, lime neutralizes the corrosive action of the dissolved carbonic acid by transforming it into calcium by the chemical reaction below:
H2O + Ca(OH)2 lime milk + 2O2
-> Ca(HCO3)2 dissolved + H2O
If the water is too hard, it forms scale, lime decarbonizes by the chemical reaction below:
Ca(OH)2 lime milk + Ca(HCO3)2 dissolved
-> 2CaCO3 insoluble + 2 H2O
Lime is more effective than any other alkaline products in producing underground drinking water. PH adjustment using lime milk is the most important use of lime
Many industries need softened water. This is very important in cooling water for circuits and
boilers, to prevent the formation of scale.
Most process water preparation techniques use lime milk. By precipitating the bicarbonates dissolved in the water, this cost-effective treatment softens the water, restricting the formation of scale.
The chemical reaction is as below:
Ca(HCO3)2 dissolved + Ca(OH)2 -> 2CaCO3 insoluble + 2 H2O