Investigation on the selectivity in the inverse flotation of iron ores by infrared spectrometry

Selectivity in the flotation of itabiritic iron ores was studied by FTIR spectrometry, after adsorption of corn starch and decyletheramine acetate, from aqueous solutions, onto the surfaces of hematite and quartz, at pH 10.5. Initially the reagents were tested separately; afterwards, they were used sequentially, starch being added first. The two reagents were found adsorbed onto the surfaces of both minerals. Selectivity occurs because, for hematite, the low amine adsorption density does not change the hydrophilic surface, previously assured by intense starch adsorption; for quartz, a higher amount of amine adsorbs onto its surface, thus changing to hydrophobic the previous hydrophilic character.