Na2 O is then dispersed in the calcined starting mixture to form a final mixture, and {HEAD ~ the final mixture} is heated in an oxygen containing atmosphere to above {TAIL ~ 1100° C.} to produce β alumina 
Na2 O is then dispersed in the calcined starting mixture to form a final mixture , and { HEAD ~ the final mixture } is heated in an oxygen containing atmosphere to above { TAIL ~ 1100 ° C. } to produce β alumina
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH