Sorption of Heavy Metals on a Coal Beneficiation Tailing Material: II. Adsorptive Particulate Flotation

A Brazilian coal jigging tailing was employed as sorbing material for heavy metal ions removal, and the flotation (DAF and Column) was used in the solid/liquid separation stage of the loaded "carrier" (adsorptive particulate flotation process--APF). Process efficiency was evaluated analyzing the residual content of metals, the supernatants turbidity, residence time, and the superficial flow rates of the solid/solution interface. Main results showed that the coal jigging tailing possesses good sorbing characteristics for heavy metal ions such as copper, zinc, and nickel and both flotation techniques were highly efficient. Ions removal (more than 90%) was higher in synthetic effluent when compared to an industrial one because the presence of complexed ions and organic reagents in actual wastewater decreases the metal ions uptake by the coal tailings. Results are discussed in terms of operating parameters, sorption mechanisms, and differences between the flotation cells and the type of wastewater.