What are the refining secrets of "elixir" summarized by ancient Ge Hong? What achievements did China make in the chemical experiment of alchemy at that time?

Ge Hong also introduced the five-spirit medicine method, Minshan Dan method, Wuchengzidan method, Xianmenzidan method, 50% Dan method, Vodafone method, Akamatsu Dan method, Cui Wenzi Dan method, Liu Yuandan method and Lechengzi method. It can be seen that the alchemist in China conducted a lot of alchemical chemistry experiments at that time, summed up a set of relatively complete operating procedures, widely used various mineral raw materials, made many chemical preparations, and observed many chemical changes.