What is meant by quicklime that has been “drowned”?
To understand this it’s important to keep in mind that then when quicklime (CaO) reacts with water it forms hydrated lime (calcium hydroxide) which is only slightly soluble in water. (0.159 grams per 100 grams of saturated solution at 25o C.) A “pebble” of quicklime, when exposed to water, will readily react and break apart due to the swelling that occurs as a result of the larger sized crystals of calcium hydroxide that are formed. As this occurs, more water enters the pebble, producing more hydrated lime, and so on. If the quicklime “pebble” is in the presence of too much water a phenomenon known as “drowning” can occur. What happens is that, although the quicklime (calcium oxide) on the surface of the pebble converts to calcium hydroxide (hydrated lime), the excess water can absorb the heat generated in the reaction and result in a delay in the hydration process. In addition, the calcium hydroxide on the surface, because of it’s limited solubility in water, will tend to block the ex
