Pure bauxite is the best raw material for the manufacture of high alumina refractories, in which maximum alumina content can be as high as _____________ percent?

Pure bauxite is the best raw material for the manufacture of high alum

1.	Pure bauxite is the best raw material for the manufacture of high alumina refractories, in which maximum alumina content can be as high as _____________ percent?
A.	55
B.	70
C.	80
D.	90
Answer» E.