Effects of Potassium Propyl Xanthate Collector and Sodium Sulfite Depressant on the Floatability of Chalcopyrite in Seawater and KCl Solutions

This study demonstrates the effects of a potassium propyl xanthate (PPX) collector and sodium sulfite (Na2SO3) depressant on pure chalcopyrite in synthetic seawater (SSW) and potassium chloride (KCl) solutions. SSW solutions with 35 g/L of salt and 0.01-M KCl were used for microflotation and zeta potential tests. Particles sized between 200# and 100# (75–150 µm) were used, and the pH was between 8.0 and 8.5. The surface of the mineral and its interaction with the collector were characterized using Raman spectrometry. The zeta potential of the chalcopyrite was measured in KCl solution at a pH range of 3–12 using the collector and depressant at a monodispersed particle size of 635# (20 µm). The results indicate that the floatability of chalcopyrite is not affected by the presence of PPX collectors in SSW solutions. SSW provides better recoveries than KCl solutions with values of 91.42% and 88.15%, respectively. The Na2SO3 depressant does not hinder the mineral floatability throughout the entire concentration range used; however, special care must be taken when adjusting the pH range to avoid increasing the zeta potential.

Direct Coupling Between Eulerian and Lagrangian Approaches in Turbulent Gas-Solid Flows

The purpose of this paper is both to present and validate the methodology of a hybrid method coupling a Eulerian and a Lagrangian approaches in turbulent gas-particle flows. The knowledge of the dispersed phase is displayed in terms of a joint fluid-particle probability density function (pdf) which obeys a Boltzmann-like equation. We chose two different ways of resolution of this equation, depending on the required level of description. The first one is a stochastic Lagrangian approach which embeds a Langevin equation for the fluid velocity seen along the particle path. The second one is a Eulerian second-order momentum approach derived in the same frame as the preceding one. These two approaches are then coupled through half-fluxes. This procedures allows well-posed boundary conditions stemmed from previous time-step statistics for the two approaches. The aim is to provide a methodology able to take into account physical phenomena such as particle bouncing on rough walls or deposition in inhomogeneous flows with a reasonable numerical cost. The paper present the methodology and validations in the case of inert monodispersed particle in a turbulent shear flow without two-way coupling. Comparisons of the results of the hybrid method with each approach and LES/DPS results indicate that the hybrid method could become a powerful simulation tool for gas-particle flows.