Study of a foam flotation process assisted by cationic surfactant for the separation of soil clay particles: processing parameters and scaling-up sensitivity

Anouar Ben Said (1) , Fabien Frances (1) , Agnès Grandjean (1) , Christelle Latrille (2) , Sylvain Faure (1)

1 CEA-DES (ex-DEN) - CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire)
2 L3MR - Laboratoire de Mesures et Modélisation de la Migration des Radionucléides

Continuous froth flotation process assisted by cationic surfactant was employed in this study, as cost-effective and environmentally friendly technology, to separate fine phyllosilicates particles of soil. A continuous flotation column was specifically designed for soil flotation. The effects of processing parameters, including collector concentration expressed as collector/soil ratio (0.1-0.4%), froth residence time (45–150 s), suspension concentration (50–125 g/L) and air flow rate (0.5–2.5 L/min), upon separation performance were investigated in order to define the operating conditions which led to the best performance. The ability of the process to separate fine phyllosilicates particles was investigated and scale-up studies were performed at pilot scale. Flotation results showed that fine particles separation (<100 $\mu$m) from soil is feasible: separation rates between 15% and 40% are reached with low concentration of surfactant. Granulometric studies showed peak densities around 3, 10 and 40 μm, attributed to phyllosilicates, phyllosilicate aggregates and quartz particles. The mineralogical composition of the extracted particles were identified and discussed. Finally, the results obtained both at lab and pilot scales emphasized good agreement which provides valuable evidence to support the technical viability of the soil flotation process for future exploitation at industrial scale.

Keywords: Flotation technology; soil remediation; separation; surfactant; phyllosilicates; colloidal particle 2

Domains: Physics [physics]; Nuclear Experiment [nucl-ex]

Anouar Ben Said, Fabien Frances, Agnès Grandjean, Christelle Latrille, Sylvain Faure. Study of a foam flotation process assisted by cationic surfactant for the separation of soil clay particles: processing parameters and scaling-up sensitivity. Chemical Engineering and Processing: Process Intensification, 2019, 142, pp.107547. ⟨10.1016/j.cep.2019.107547⟩. ⟨cea-02517876⟩