Abstract: The present invention relates to a novel process and to an installation for performing the process for calcining limestone for producing lime of different qualities, while being able to entirely or at least substantially do without conventional energy carriers such as coal, oil and natural gas. Instead waste energy carriers of different origins are used. According to the process the waste energy substances are firstly gasified in a suitable gasifier, which is constructed as a shaft reactor or fluidized bed reactor and at elevated temperature, the dust being then removed from the lean gas produced and subsequently passed into the combustion chambers of the gasification reactor where burning takes place. The pollutants in the waste energy carriers are destroyed or rendered harmless by the high temperature of approximately 1600.degree. C. in the gasification reactor. Dust and harmful components are then deposited in the coke filling or in the dust catchers.