Uses of limestone 1. Limestone is mainly calcium carbonate 2. Limestone can be quarried and used as a building material. 3. It is used in the making of glass, cement, concrete, toothpaste, bread and is used to neutralise lakes and soil Uses of limestone Heating limestone 1. When limestone is heated in a kiln it breaks down into quicklime (calcium oxide) 2. This reaction is called thermal decomposition 3. Quicklime reacts with water to produce slaked lime (calcium hydroxide) which is used to reduce the acidity of soil Making Quicklime Making Quicklime Making Slaked lime Making Slaked lime Limestone Cycle Limestone Cycle Limestone Cycle Limestone – Benefits/Problems