lime-soda method
Quick Summary
The lime-soda method is a process used for water softening, which removes dissolved calcium and magnesium salts that cause water hardness. Hard water can lead to scale buildup in pipes and interfere with cleaning agents like soap.12
In this method, chemicals are added to precipitate hardness-causing minerals. Specifically, lime (calcium hydroxide) is used to precipitate calcium as carbonate and magnesium as hydroxide. Then, sodium carbonate (soda ash) is added to remove any remaining calcium salts. The process requires subsequent sedimentation and filtration to remove the precipitates.12
Soda lime itself is a mixture of calcium hydroxide with sodium or potassium hydroxide, primarily used as an absorbent for moisture and gases like carbon dioxide.34
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