| 423 / | HD | CHEMISTRY OF INORGANIC COMPOUNDS |
| 1 | DF | TREATING MIXTURE TO OBTAIN METAL CONTAINING COMPOUND {15} |
| 155 | DF | .~ Alkaline earth metal (Mg, Ca, Sr, or Ba) {11} |
| 157.2 | DF | .~.~ Phosphate rock or ore {1} |
| 157.3 | | .~.~.~ Acid treatment {1} |
| 157.4 | DF | .~.~.~.~> Sulfating |