162 / | HD | PAPER MAKING AND FIBER LIBERATION |
1 | DF | PROCESSES OF CHEMICAL LIBERATION, RECOVERY OR PURIFICATION OF NATURAL CELLULOSE OR FIBROUS MATERIAL {33} |
70 | DF | .~ Treatment with particular chemical {9} |
90 | .~.~ Alkali metal, ammonium, alkaline earth metal or magnesium hydroxide or carbonate |