Quicklime is made from calcium carbonate stones at a kiln using the smelting labor. It can be processed into milk of lime at an ashery, which is further used to create parchment.
The reaction needs 1 calcium carbonate stone and 1 unit of fuel except when using a magma kiln. It also needs an empty bag.
Source: commons.wikimedia.org/wiki/File:Calcium_oxide_powder.JPG