Alumina Health Dictionary

The term applied to water that contains a large amount of calcium and magnesium salts (lime salts). These form an insoluble curd with soap and thus interfere with the use of the water for washing. Hard water is especially found in districts where the soil is chalky. Temporary hardness, which is due mainly to the presence of bicarbonates of lime, can be remedied by boiling, when the lime is precipitated as carbonate of lime. Permanent hardness is not remedied by boiling, and is due to the presence of a large amount of sulphate of lime. It may be removed by the addition of sodium carbonate (washing soda) or by the Permutit process which involves the use of various combinations of silicate of alumina and soda. In the past, hard water was often blamed for many ills – without any convincing evidence. Epidemiologists suggest that drinking soft water may lead to a greater risk of heart disease.... hard water