Behavioral and Mechanistic Analyses of Thermal Bursting of Low-Grade Limestones

Thermal bursting and pulverization during calcination adversely affect the production of quicklime from low-grade limestones. This study investigates the mechanisms of these phenomena across different temperature stages by integrating thermogravimetric, microstructural, and phase composition analyses. During low-temperature calcination, bound water decomposition induces self-propagating cracks in both the matrix and boundary regions. During mid-temperature calcination, carbonate decarbonation causes pore formation and shrinkage, promoting crack propagation from the boundary into the matrix. When calcined at high-temperature, complete phase transformation and the anisotropic structure of boundary dolomite collectively led to through-crack development. The differing thermal properties and microstructures of calcite and dolomite are thus identified as the primary factors governing crack evolution and thermal bursting behavior.