Flotation behavior and kinetic characteristics of trace elements in coal

Abstract

ABSTRACT Flotation is considered as an efficient method for removing hazardous trace elements from coal. However, the flotation kinetic characteristics of trace elements in coal are still missing. This research presents a detailed investigation into the flotation behavior of As, Se, Pb, Be, and Hg in coal, using coal samples from TX and FGZ coal preparation plants. Six kinetic models were employed to describe their flotation behavior and separation efficiency was introduced to assess the removability of trace elements. Most of the coal floats within the first 2 minutes of flotation, with the highest yield observed in product C1, followed by C4. The trace elements content (excluding Pb) exhibited an increasing trend from C1 to C6, and trace elements were primarily distributed in the tailing. There is a strong positive correlation between cumulative trace elements and ash content, and the inorganic-affinity of trace elements in FGZ coal is stronger compared to that of TX coal. The second-order model with a rectangular distribution of floatability provides the most appropriate description of trace elements’ flotation behavior. Kinetic analysis and separation efficiency assessments demonstrated that As and Hg in FGZ coal are relatively easier to discharge, while Pb and Be in TX coal exhibit higher removability.