▁reduced ▁( i . e . ▁the ▁sor b ent ▁can ▁be ▁made ▁to ▁work ▁more ▁efficiently ), ▁the ▁reduction ▁in ▁material ▁consumption ▁and ▁waste ▁can ▁lower ▁feed stock ▁demand ▁and ▁operating ▁costs . ▁ ▁C ement ▁production ▁Finally , ▁favor able ▁econom ics ▁can ▁be ▁achieved ▁by ▁using ▁the ▁p urg ed ▁material ▁from ▁the ▁calci um ▁looping ▁cycle ▁in ▁c ement ▁production . ▁The ▁raw ▁feed ▁for ▁c ement ▁production ▁includes ▁~ ▁ 8 5   wt % ▁lim estone ▁with ▁the ▁remaining ▁material ▁consisting ▁of ▁cl ay ▁and ▁add it ives ▁( e . g . ▁Si O 2 , ▁Al 2 O 3 ▁etc .). ▁The ▁first ▁step ▁in ▁the ▁process ▁involves ▁cal cin ating ▁lim estone ▁to ▁produce ▁Ca O , ▁which ▁is ▁then ▁mixed ▁with ▁other ▁materials ▁in ▁a ▁kil n ▁to ▁produce ▁cl ink er . ▁ ▁Using ▁p urg ed ▁material ▁from ▁a ▁Ca - loop ing ▁system ▁would ▁reduce ▁the ▁raw ▁material ▁costs ▁for ▁c ement ▁production . ▁W aste ▁Ca O ▁and ▁ash ▁can ▁be ▁used ▁in ▁place ▁of ▁Ca CO 3 ▁( the ▁main ▁constitu ent ▁c ement ▁feed ). ▁The ▁ash ▁could ▁also ▁ful fill ▁the ▁al um inos il icate ▁requirements ▁otherwise ▁supplied ▁by ▁add it ives . ▁Since ▁over ▁ 6 0 % ▁of ▁the ▁energy ▁used ▁in ▁c ement ▁production ▁goes ▁into ▁heat ▁input ▁for ▁the ▁pre calc iner , ▁this ▁integration ▁with ▁Ca - loop ing ▁and ▁the ▁consequ ent ▁reduced ▁need ▁for ▁a ▁calc ination ▁step