IONIC-STRENGTH EFFECTS IN DIAMINE FLOTATION OF QUARTZ AND MAGNETITE

The flotation of quartz and magnetite was studied as a function of pH when using N-alkyl-1, 3 diaminopropanes and n-dodecylamine as collectors. The alkyl chains of the diamines were 8, 12 and 16 carbons in length. Two collector concentrations were used and flotation sludged in the absence of additives and in the presence of NaCl. The chain length effect on flotation using the diamines is comparable to that observed in flotation using monoamines. All the amines are relatively stronger collectors for quartz than for magnetite. The NaCl, in the concentration studied, 0.6 kmol/m3, function as a depressant for the minerals. The 12 C diamine is a stronger collector for the minerals than the 12 C monoamine. Probable surface chemical phenomena giving rise to the observed experimental results are discussed.