Differences in Etheramines Froth Properties and the Effects on Iron Ore Flotation. Part II: Three-Phase Systems

Part I of this investigation, addressing two-phase systems, showed that etherdiamine produces more stable and dryer foams, whereas smaller bubbles are formed with faster kinetics by ethermonoamine. These remarkable differences in foam stability, attributed to the distinct chain length and consequent hydrophilic-lipophilic balance, influence froth properties, and may affect the selectivity of reverse cationic flotation of iron ores. The investigations conducted in this paper evaluated the effect of froth properties on the selective flotation recovery of a Brazilian iron ore from the Iron Quadrangle. The results showed that etherdiamine presented faster kinetics of froth formation but the recovery of water and solids in the froth was lower than that achieved with ethermonoamine. The water recovery was closely related to nonselective transport of solid particles in the froth by entrainment. The etherdiamine ability to form more stable and dryer froth reduced the entrainment of fine iron-bearing particles in the froth (tailings), improving the metal recovery in the concentrate (bulk), as the iron loss was directly proportional to the water recovery in the froth and the reagent presented lower entrainment factor than the ethermonoamine. In addition, the drier froth from etherdiamine is responsible for greater quartz true flotation, rendering this collector a more selective effect on flotation in spite the more powerful effect of ethermonoamine.

Automated summary

The investigation showed significant differences in foam stability between etherdiamine and ethermonoamine, with etherdiamine producing more stable and drier foams while ethermonoamine forming smaller bubbles with faster kinetics. These differences in foam properties affect the selectivity of reverse cationic flotation of iron ores, with water and solids recovery rates showing a significant impact on froth properties.