Abstract: A process for calcining a feed material can include passing a solid particulate material through a burner or adjacent a burner for being pass through a flame formed by the burner to facilitate calcination of the material. The material can be emitted from the flame of the burner within a calciner for passing through a body of the calciner to an outlet for further calcination of the material so the material has a pre-selected residence time as it is passed through the flame and calciner to an outlet. The residence time can be 20 seconds to 30 seconds, 1-3 minutes, less than 5 minutes in some embodiments. Some embodiments can facilitate calcination of a CaCO3 material so the calcined solid material output from a calciner is comprised of Ca(OH)2 (e.g. is mostly Ca(OH)2, is over 90 weight percent Ca(OH)2, etc.).