The method 1 wherein the heating in step is from {TAIL ~ about 1100° C.} to {HEAD ~ about 1360° C} 
The method 1 wherein the heating in step is from { TAIL ~ about 1100 ° C. } to { HEAD ~ about 1360 ° C }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD