Don't you hate waiting millenia and wasting stacks of precious coal that could fuel your steel just to make a few bricks or ashlar?
This could be a solution:The Shaft Lime Kiln
Faster,and a bit less wasteful perhaps.A multi block structure that uses fire clay bricks or refractory,maybe 5 blocks tall.
Grates on it's bottom,and stacks of coal above it.Ignite and place stacks of lime inside.Wait a day.And there you go.
Wikipedia:
A lime kiln is a kiln used for the calcination of limestone (calcium carbonate) to produce the form of lime called quicklime
Shaft kilns
The theoretical heat (the standard enthalpy) of reaction required to make high-calcium lime is around 3.15 MJ per kg of lime, so the batch kilns were only around 20% efficient. The key to development in efficiency was the invention of continuous kilns, avoiding the wasteful heat-up and cool-down cycles of the batch kilns. The first were simple shaft kilns, similar in construction to blast furnaces. These are counter-current shaft kilns. Modern variants include regenerative and annular kilns. Output is usually in the range 100–500 tonnes per day.