Question

Metallurgy question:

Reagent addition is very important to the froth flotation process. In this regard, below are several reagent(mineral)/mineral combinations. Give the expected response the reagent will have on the mineral in terms of its surface chemistry and flotation behavior. In all cases identify the reagent in terms of its appropriate flotation term (i.e. collector, activator etc.).

a.       xanthate/FeS2 (pH 10)

b.       Cu++/ZnS

c.       dextrin/coal

d.       oleate (oleic acid)/ BaSO4 pH 10

e.       dodecylamine/SiO2 pH 5

f.       dodecylamine/SiO2 pH 1.5

g.       Fe2O3 particles (1 micron diameter)/ SiO2 particles (100 micron diameter), note desire to concentrate SiO2 with dodecylamine collector, pH 5.

Answer 1

xanthate/FeS2 (pH 10) The most widely-used collectors in sulphide mineral flotation are the xanthates. They are classified as Anionic reagents.

Cu++/ZnS – (Activators )There are a number of metal ions which can be used to activate sphalerite - a zinc mineral that does not respond well to xanthate collectors. Zinc xanthate is readily soluble so by replacing zinc in the crystal lattice at the mineral surface with a metal ion that can form stable xanthate salts, adsorption of collector is possible. Copper sulphate is readily soluble but is a very expensive reagent. No other controllable, cheap reagent has yet been found.

dextrin/coal – (depressants) can be used to prevent collector adsorption on specific minerals.

oleate (oleic acid)/ BaSO4 pH 10 – (collectors) salts of oleic acid, particularly sodium oleate, are among the collectors traditionally employed for the flotation recovery of Barite.

dodecylamine/SiO2 pH 5 and dodecylamine/SiO2 pH 1.5 (collectors) With increasing pH , recovery increases. pH 10 is the optimum condition for maximum recovery of quartz.