(1)3000t*97%=2910t (铁的质量),2910t/(56*3/(56*3+16*2))=3464.3t(二氧化三铁的质量),3464.3t/70%=4949t(赤铁矿质量)
(2)2910t/(56*3/(56*3+16*4))=4019.3t(二氧化三铁的质量),4019.3t/70%=5742t(赤铁矿质量)