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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.
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.
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.
Calcium hydroxide (traditionally called slaked lime) is an inorganic compound with the chemical formula Ca 2. It is a colorless crystal or white powder and is produced when quicklime (calcium oxide) is mixed with water. Annually, approximately 125 million tons of calcium hydroxide are produced worldwide. [8]
Alkali soils owe their unfavorable physico-chemical properties mainly to the dominating presence of sodium carbonate, which causes the soil to swell [1] and difficult to clarify/settle. They derive their name from the alkali metal group of elements, to which sodium belongs, and which can induce basicity .
In the lime industry, limestone is a general term for rocks that contain 80% or more of calcium or magnesium carbonate, including marble, chalk, oolite, and marl.Further classification is done by composition as high calcium, argillaceous (clayey), silicious, conglomerate, magnesian, dolomite, and other limestones. [5]
An 1836 lithograph of tortilla production in rural Mexico Bowl of hominy (nixtamalized corn kernels). Nixtamalization (/ ˌ n ɪ ʃ t ə m ə l ɪ ˈ z eɪ ʃ ən / nish-tə-mə-lih-ZAY-shən) is a process for the preparation of maize (corn), or other grain, in which the grain is soaked and cooked in an alkaline solution, usually limewater (but sometimes aqueous alkali metal carbonates), [1 ...
He became known for the discovery of the phosphate of soda, and the process of lime softening of hard water the 'Clark process'. A Clark degree (°Clark) of water hardness is defined as one grain (64.8 mg) of CaCO 3 per Imperial gallon (4.55 litres) of water, equivalent to 14.254 ppm. and 10^5 parts of water