| 502 / | HD | CATALYST, SOLID SORBENT, OR SUPPORT THEREFOR: PRODUCT OR PROCESS OF MAKING |
| 60 | DF | ZEOLITE OR CLAY, INCLUDING GALLIUM ANALOGS {13} |
| 80 | DF | .~ Clay {2} |
| 81 | | .~.~ Acid treating {2} |
| 82 | DF | .~.~.~> Plural acid treatment |
| 83 | DF | .~.~.~> Sulfuric or hydrochloric acid |