A.30%~40%B.20%~30%C.40%~50%
A.密封B.潤滑C.磨損嚴(yán)重
A.細(xì)粒級(jí)物料得不到有效分選B.精煤質(zhì)量下降C.精煤質(zhì)量提高D.無影響