Froth flotation

A method of recovering a mineral comprising at least one of arsenopyrite and pyrrhotite, while selectively rejecting pyrite, from a material containing said material together with pyrite, said method comprising the steps of

• providing a slurry containing said material, said slurry having an upper surface,
• adding as a collector for said mineral a dialkyl-dithiophosphate of formula (I) ##STR5## wherein R=alkyl of 3 to 8 carbon atoms;
• and
• M=alkali metal or ammonium
• to the slurry, passing a gas through the slurry causing the mineral to be selectively carried to the surface of said slurry and report in a first float concentrate while leaving a portion of said mineral and most of said pyrite in the resultant slurry,
• adding a water soluble copper salt to the resultant slurry to activate the remaining mineral and also adding as a collector for said mineral a monoalkyl-dithiocarbamate of formula (II) ##STR6## wherein R'=alkyl of 3 to 10 carbon atoms, and
• M=alkali metal or ammonium.
• passing a gas through the slurry to cause the remaining mineral to be selectively carried to the resultant slurry surface and report in a second float concentrate while the pyrite remains in the second resultant slurry, and
• recovering the minerals from said first and second concentrates.