在炼丹的过程中，炼丹术士们围绕着丹砂以及与丹砂有关的物质进行了各种可能性的探索和实验，并了解到了许多相关的化学知识。

During the process of refining pills, some alchemists had understood chemical knowledge by various kinds of possible experiments and exploration on cinnabar and related materials.