Flotabilidade de hematita e quartzo com amina e amido dosados em microemulsões e nanoemulsões

Abstract

The proper use of low-grade iron ore and its wastes is imperative to obtain a reasonable development for sustainable industrial growth. Reverse cationic flotation is an effective process when used in iron ore beneficiation. In this process, quartz, which is the main gangue mineral, is floated with cationic collectors (amines). Starch is usually used in iron oxide depression. Surfactant adsorption at the liquid / air and solid / liquid interfaces plays an important role in many technological and industrial applications such as emulsification, mineral flotation, and solid dispersion. In this work quartz and hematite microflotation was performed using microemulsion and nanoemulsion systems. Microemulsion and nanoemulsions systems were composed by: surfactant (Flotigam EDA or Ultramine 150 ), co-surfactant (n-butyl alcohol), oil phase (kerosene), and aqueous phase or depressant solutions (Maizena , soluble starch, amylose, or amidex). The influence of operational parameters, such as concentration and type of surfactant, concentration and type of depressant, and pH were evaluated. The results show that the performance of nanoemulsions is superior to that of microemulsions, as well as the use of monoamine alkyl ether solutions (conventional method). Maizena , soluble starch, amidex, and amylose depressants in nanoemulsified systems containing Flotigam EDA , kerosene, and n-butyl alcohol showed high floatability for quartz even at the highest concentrations of depressors tested and were able to depress hematite, showing no evidence for clathrate formation. Nanoemulsions with Ultramine 150 nonionic surfactant reached the maximum floatability percentages for quartz (99.16%) and optimal hematite depression (89.10%). These results show that the use of nanoemulsions in the reverse flotation process has potential application in iron ore concentration, simplifying and leading to an improvement of the conventional stepwise process.