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Lime softening (also known as lime buttering, lime-soda treatment, or Clark's process) [1] is a type of water treatment used for water softening, which uses the addition of limewater (calcium hydroxide) to remove hardness (deposits of calcium and magnesium salts) by precipitation.
Lime mortar or torching [1] [2] is a masonry mortar composed of lime and an aggregate such as sand, mixed with water. It is one of the oldest known types of mortar, used in ancient Rome and Greece , when it largely replaced the clay and gypsum mortars common to ancient Egyptian construction.
The conditions and compounds present during each step of the lime cycle have a strong influence of the end product, [8] thus the complex and varied physical nature of lime products. An example is when slaked lime (calcium hydroxide) is mixed into a thick slurry with sand and water to form mortar for building purposes. When the masonry has been ...
Water softening is the removal of calcium, magnesium, and certain other metal cations in hard water. The resulting soft water requires less soap for the same cleaning effort, as soap is not wasted bonding with calcium ions. Soft water also extends the lifetime of plumbing by reducing or eliminating scale build-up in pipes
Feebly hydraulic lime (NHL 2) is used for internal work and external work in sheltered areas. Feebly hydraulic lime contains up to 10% clay / clay mixed with other impurities. It might take one week or more to set after the addition of water. Setting is the process of permanently taking the shape into which lime has been moulded.
Lime plastering is composed of lime, sand, hair and water in proportions varying according to the nature of the work to be done. The lime mortar principally used for internal plastering is that calcined from chalk , oyster shells or other nearly pure limestone , and is known as fat, pure, chalk or rich lime.
If the water is acidic (lower than 7), lime, soda ash, or caustic soda (sodium hydroxide) can be added to raise the pH during water purification processes and is especially common practice for water softening. The choice of chemical used for raising the pH often depends on the carbonate alkalinity in the water.
The lime industry is a significant carbon dioxide emitter. The manufacture of one tonne of calcium oxide involves decomposing calcium carbonate, with the formation of 785 kg of CO 2 in some applications, such as when used as mortar ; this CO 2 is later re-absorbed as the mortar goes off.