Hydrated Lime is a dry powder mainly composed of calcium hydroxide Ca(OH)2. It is a colorless or white powder, which is obtained by hydrating Quicklime (Calcium Oxide) using specific equipment called hydrator in a process called ration. The process converts CaO to Ca(OH)2. Actually, hydration is a chemical process in which water molecules combine with Quicklime. CaO + H2O → Ca(OH)2 + Heat Hydrated Lime has other common names like Slaked Lime, Caustic Lime, Builder’s Lime, and Slack Lime.