mixing {TAIL ~ the ammonia containing solution} with the recovered solid phase to neutralize {HEAD ~ the solid phase} and to enrich it in nitrogen 
mixing { TAIL ~ the ammonia containing solution } with the recovered solid phase to neutralize { HEAD ~ the solid phase } and to enrich it in nitrogen
OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH