A Study of Kinetics on Oily-Bubble Flotation for a Low-Rank Coal

摘要

The flotation performance and kinetics for a low-rank coal were investigated using air bubbles and oily bubbles. Five flotation kinetic models were applied to the test data to estimate the relationships between the flotation rate constant, the maximum recovery, and the collector dosage. The results showed that the oily-bubble flotation (OBF) obtained lower ash content and higher combustible recovery with less collector dosage than the air-bubble flotation (ABF). But this advantage of OBF gradually diminished with the collector dosage. It was found that the flotation of a low-rank coal in ABF and OBF can be best described with the second-order kinetic model and classical first-order model, respectively. The OBF had higher maximum combustible recovery values and lower maximum ash recovery values. The flotation rate constants of OBF were higher in all the models except the fully mixed reactor model. Furthermore, the effect of collector dosage on the low-rank coal flotation kinetics was evaluated. It was indicated that the maximum recovery values and modified rate constants increased with the collector dosage. The similar trend was observed in the flotation rate constants for all of the models except the fully mixed reactor model.