Lime and Limestone

Abstract Limestone is a widely distributed sedimentary rock composed principally of calcium carbonate. It underpins major industrial sectors, notably construction materials, metallurgy, agriculture, water treatment, and chemical manufacture. This entry reviews limestone formation, classification, and key physical and chemical properties relevant to processing and end use. The manufacture of lime products, such as quicklime (CaO) and slaked/hydrated lime (Ca(OH) 2 ), is described with a focus on raw material requirements, kiln technologies, energy performance, product reactivity, and processing to final products. Major applications and specifications are summarized for building limes, steelmaking fluxes, environmental remediation, and high‐purity chemical uses such as precipitated calcium carbonate. Health, safety, and environmental considerations are included, such as novel routes for abatement of production‐related CO 2 emissions. Emerging low‐carbon alternatives to conventional thermal calcination (electrochemical and alkaline conversion pathways) are introduced as potential decarbonization options for lime and limestone processing.