Investigating the thermodynamics and adsorption mechanisms of alkaline gelatinised novel depressants on pyrite surface

The depressant-pyrite adsorption thermodynamics, adsorption isotherms, and depression were investigated using adsorption and microflotation studies. The adsorption studies showed that the adsorption of CMC (carboxymthyl cellulose) and LBG (locust bean gum) fit the Freundlich isotherms while CTG (cassia tora gum) fit the Langmuir isotherms as demonstrated by their respective R². Therefore, CMC and LBG adsorbed onto the pyrite surface by forming both single and multilayer, while CTG adsorbed onto the pyrite surface by creating a monolayer. In addition, the cumulative adsorption densities onto pyrite surfaces were 539, 443, and 372 mg/m² for CTG, LBG, and CMC, respectively. Furthermore, the thermodynamics studies revealed that all three depressants' adsorption onto the pyrite surface was nonspontaneous and occurred via physisorption, as demonstrated by positive ΔG^O and ΔH values < 80 kJmol⁻¹, respectively. Lastly, the percentage of pyrite depression achieved in the microflotation studies decreased in the order LBG > CTG > CMC; their respective values were 87% > 60% > 38%.