ABSTRACT
Sulfation is the conversion of mineral values in an ore into sulfates by dry methods. This method is applied to minerals that yield water-soluble sulfates so that it can be followed by leaching with water. The decomposition vapor pressure of some sulfates. It can be seen that the thermal stability is spread over a wide temperature range, that is, some sulfates are more stable than others. Therefore, the thermal stability can be roughly predicted from the heat of decomposition, or more exactly from the free energy of decomposition. The thermal stability of sulfates vary greatly. Alkali sulfates are fairly stable; when heated they melt and then evaporate with only a slight decomposition to an oxide which dissolves in the remaining sulfate. The fact that the decomposition temperature of sulfates varies was suggested to achieve selectivity in sulfation, that is, sulfating a certain mineral in the ore in preference to others.
