wherein the pH of the slurry is not adjusted in {HEAD ~ any} of {TAIL ~ steps}  
wherein the pH of the slurry is not adjusted in { HEAD ~ any } of { TAIL ~ steps }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH