Leaching of pyrrhotite with hydrochloric acid

AbstractWhen nonstoichiometric pyrrhotite is leached under nonoxidizing conditions in warm aqueous solutions containing HCl, both hydrogen sulphide and elemental sulphur are formed. The amount of sulphur is proportional to the nonstoichiometry of the pyrrhotite. The leaching reaction is rapid (only seconds required to completion) but, when minimum conditions of acidity and/or temperature are not met, the sulphur coating becomes protective and the reaction ceases. When the reaction is begun rapidly, all of the acid or all of the pyrrhotite will be consumed, depending upon which is in excess. In hydrochloric acid, pentlandite dissolves more slowly than pyrrhotite but chalcopyrite is almost insoluble. Resume A des temperatures au-dessous de 100°C quand les pyrrhotines de composition non stoichiometriques sont lixiviees par des solutions d'acide chlorhydrique en milieu non-oxydant, les produits de la reaction sont l'hydrogene sulfure et le soufre. La quantite de soufre produit est proportionnelle au degre de ...