Qinbo Cao

Synergistic effect of dodecyl sulfonate on apatite flotation with fatty acid collector

ABSTRACT The synergistic effects between sodium dodecyl sulfonate (SDS) and a mixed fatty acids collector for apatite flotation were investigated. SDS benefitted the apatite flotation at pH 9.5. The TOC measurements showed that the addition of SDS improved the surfactants adsorption at the apatite surface. The colloidal size measurements suggested that the utilizing of SDS prevented the over-packing of fatty acids in the solution. Additionally, SDS did not adsorb/co-adsorb at the apatite surface as revealed by the FTIR and XPS results, because of the strong electrostatic repulsion between the apatite surface and the SDS ions.

Dissolution kinetics of cerussite in an alternative leaching reagent for lead

The dissolution kinetics of cerussite was investigated using methanesulphonic acid (MSA) as an alternative leaching reagent. The effects of particle size, stirring speed, acid concentration, and reaction temperature on the lead dissolution rate were determined. The dissolution process followed the kinetic law of the shrinking-core model, and a corresponding mixed control model was found suitable for representing the rate-controlling step. The mixed kinetic model comprised two stages: surface chemical reaction (283 K to 303 K) and diffusion through the product layer (303 K to 323 K). The activation energies of these sequential stages were 43.20 kJ mol−1 and 17.20 kJ mol−1, respectively. The corresponding dissolution kinetic equations are also presented to describe the dissolution reaction. The results indicated that methanesulphonic acid could be used as an effective leaching reagent for extracting lead from cerussite minerals.