Rectified spirit can be converted into absolute alcohol by distilling with

Absolute alcohol is created in the laboratory by exposing the rectified spirit to a calculated amount of quick lime ($CaO$) for a few hours before refluxing and distilling it.
$$\begin{gathered} \Rightarrow \underset{\downarrow }{\mathrm{Rectified} \mathrm{spirit} \mathrm{contain}} \approx 95\% \mathrm{ethanol} \\ \mathrm{destilling} \mathrm{with} \mathrm{CaO} (\mathrm{Quick} \mathrm{lime}) \end{gathered}$$