What is solid phase reaction?

Chemical reactions involving solids are solid-phase reactions, including reactions between solids and gases, reactions between solids and liquids, etc.

Solid-phase reactions include: reactions of a single solid substance, such as thermal decomposition of limestone; gas-solid phase reactions, such as the burning of magnesium strips; liquid-solid phase reactions, such as hydrochloric acid dissolving limestone; solid-solid phase reactions, such as calcium sulfate and calcium sulfate

Preparation of calcium sulfide from charcoal; reactions on the surface of solid materials, such as platinum-catalyzed organic chemical reactions.

If a reaction must involve a solid substance in a certain environment to occur, the reaction is a solid-phase reaction.