{HEAD ~ Addition} of up to 60 wt% organic acid to the calcium hydroxide solution or {TAIL ~ suspension} is preferred 
to
{ HEAD ~ Addition } of up to 60 wt% organic acid to the calcium hydroxide solution or { TAIL ~ suspension } is preferred
HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH REL OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH