The foam generated in iron ore flotation is usually pumped via pipeline to a tailings reservoir. However, pumping foamy slurry reduces the system efficiency and also increases maintenance costs (pump wear). Quartz, the main waste mineral contained in iron ore, is generally floated by means of cationic reverse flotation at alkaline pH. In this process the etheramine is used as a collector and as a foaming agent. These functions are due to amine dissociation in aqueous solution, in which the molecular and ionic species co-exist. In this chemical equilibrium, acidity favors the dissociated form and alkalinity favors the molecular form. The work focuses on reducing aeration of slurry, targeting an improvement in tailings pipeline operation by improving centrifugal pump performance. Initially, alternatives were analyzed to reduce foam stability, through slurry neutralization – pH 7.5. After neutralization, bubbles still exist, but with less stability. After acid dosing, high pressure water is sprayed on the treated slurry. The water spray to reduce bubble stability is a complementary treatment to neutralization. The lab tests show reduced foaming factor, when the treatment is used (neutralization combined with water spray).
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