How did Antoine Lavoisier explain calcination?

Antoine Lavoisier explained calcination by demonstrating that it is a process of oxidation rather than the release of a hypothetical substance called phlogiston.12

Through precise measurements of weight, Lavoisier observed that when metals were converted into powders known as calxes, they gained weight rather than losing a "fiery substance". He hypothesized that this weight gain resulted from the metal chemically combining with a specific gas from the atmosphere.12

After learning of Joseph Priestley's discovery of "dephlogisticated air," Lavoisier identified this gas as the active component in the air responsible for calcination, combustion, and respiration. He named this gas oxygen, meaning "acid producer," and established that during calcination, the metal absorbs oxygen to form a calx. This theory successfully replaced the phlogiston hypothesis by providing an experimentally grounded, quantitative explanation for the chemical changes observed in these reactions.123