The operations of alchemy are the stages of the Great Work: calcination, dissolution, separation, conjunction, fermentation, distillation, coagulation and their variants. Each names a physical process at the bench (burning to ash, dissolving in liquid, separating the parts, rejoining them), and, at the same time, a stage in the transformation of the alchemist's own soul.
Different authors list different numbers of operations (seven, twelve, or others), and the same name does not always mean the same thing from one text to another, so the sequence is less a fixed recipe than a family of related schemes.