Lime is a commonly used name for two slightly different substances. One is Calcium oxide with chemical formula Cao and the other is Calcium Hydroxide with chemical formula CaOH. Calcium oxide is also called quicklime and calcium hydroxide is also called slaked lime of hydrated lime.
Quicklime is produced by crushing and heating limestone, which chiefly consists of calcium carbonate with the chemical formula CaCO3. On being heated temperature of 1204 degrees centigrade, the calcium carbonate releases carbon dioxide and turns in to quicklime.
When Quicklime is mixed with water it combines with water releasing lot of heat, On drying up the residual remaining is slaked lime.
If extra water is added to quicklime during process of slaking, part lime gets dissolved in water producing a milky white slurry. This mixture is called milk of lime. If still more water is added the lime gets completely dissolved and a clear solution is obtained which is called lime water.
Cements are of different types. Portland cement, the most common type of cement contains about 60% lime, 25% silica, 5% alumina and some additional material like iron oxide and gypsum. cement is made by crushing together raw material containing the required ingredient in right proportion in heating them to a very high temperature. This process produces lumps of cement, which are then crushed to make fine powder.