In Malang Regency, there is an area that produces quicklime (CaO), which is widely used in the building materials industry. Quicklime is made from burning limestone (CaCO₃), which is a hard rock formed from the sedimentation of marine organisms such as shells, snails, shells, and corals. The burning process is carried out at high temperatures using fuel, and some even use plastic waste. However, the use of plastic waste as fuel causes environmental problems because it can produce toxic gases and CO₂, which contribute to global warming and have a negative impact on health.

  To obtain high-quality quicklime with a CaO content of around 90%, limestone must be continuously burned at a temperature of 900–1000°C for 16–50 hours. Burning cannot be done in a short time because the process of decomposing limestone into quicklime requires a large amount of heat energy and sufficient time for the decomposition reaction to take place completely.

  Why must limestone be burned continuously to produce pure lime?