introducing alumina into the tank at a slow rate CL which is from {HEAD ~ 15 to 50%} below {TAIL ~ the normal rate} of alumina consumption CN 
below
introducing alumina into the tank at a slow rate CL which is from { HEAD ~ 15 to 50 % } below { TAIL ~ the normal rate } of alumina consumption CN
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH