Definition of calcining:
(v) :
(transitive) (physical chemistry) To heat (a substance) without melting in order to drive off water, etc., and to oxidize or reduce it; specifically, to decompose (carbonates) into oxides, and, especially, to heat (limestone) to form quicklime.
(v) :
(transitive) (by extension) To heat (something) to dry and sterilize it.
(v) :
(transitive) (figuratively) To purify or refine (something).
(v) :
(transitive) (figuratively) To burn up (something) completely; to incinerate; hence, to destroy (something).
(v) :
(intransitive, physical chemistry) Of a substance: to undergo heating so as to oxidize it.
(n) :
Something calcined; also, material left over after burning or roasting.