HU Zhangfu，LIU Yang，GAO  Youliang，OU Keying

(Engineering Department)

Abstract :  A test on chemical  bleaching of longyan  and Jiangxi Tonggu's  kaolins which are weathering residual ores was carried out, the result of which shows that the whiteness of samples was increased from  78%  to 88%, and a new bleaching technique  with oxalic acidsodium  hydrosulfite and single oxalic  acid  was determined.  This  technique  possessed  a  good  bleaching  effect. And  the  product quality is stable.

Keywords:  Kaolin, de-ironing, bleaching, hydrosulfite, oxalic acid.