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