▁provide ▁heat ▁to ▁a ▁building ▁or ▁used ▁to ▁m elt ▁subst ances ▁such ▁as ▁glass ▁or ▁metal ▁for ▁further ▁processing . ▁A ▁bl ast ▁furn ace ▁is ▁a ▁particular ▁type ▁of ▁furn ace ▁generally ▁associated ▁with ▁metal ▁sm el ting ▁( part icular ly ▁steel ▁manufact ure ) ▁using ▁ref ined ▁co ke ▁or ▁similar ▁hot - burn ing ▁subst ance ▁as ▁a ▁fuel , ▁with ▁air ▁p ump ed ▁in ▁under ▁pressure ▁to ▁increase ▁the ▁temperature ▁of ▁the ▁fire . ▁A ▁black sm ith ▁uses ▁a ▁tempor arily ▁blow n ▁furn ace , ▁the ▁sm ith ' s ▁heart ▁to ▁heat ▁iron ▁to ▁a ▁g low ing ▁red ▁to ▁yellow ▁temperature . ▁ ▁A ▁kil n ▁is ▁a ▁high - temper ature ▁o ven ▁used ▁in ▁wood ▁dry ing , ▁cer am ics ▁and ▁c ement ▁manufact uring ▁to ▁convert ▁min eral ▁feed stock ▁( in ▁the ▁form ▁of ▁cl ay ▁or ▁calci um ▁or ▁al umin um ▁rocks ) ▁into ▁a ▁glass ier , ▁more ▁solid ▁form . ▁In ▁the ▁case ▁of ▁cer am ic ▁kil ns , ▁a ▁sh aped ▁cl ay ▁object ▁is ▁the ▁final ▁result , ▁while ▁c ement ▁kil ns ▁produce ▁a ▁subst ance ▁called ▁cl ink er ▁that ▁is ▁cr ushed ▁to ▁make ▁the ▁final ▁c ement ▁product . ▁( C ertain ▁types ▁of ▁dry ing ▁o vens ▁used ▁in ▁food ▁manufact ure , ▁especially ▁those ▁used ▁in ▁mal ting , ▁are ▁also ▁referred ▁to ▁as ▁kil ns .) ▁ ▁An ▁aut oc lave ▁is ▁an