Spontaneous Surface Convection and Extraction (Stripping) Rate in Systems with Tributyl Phosphate and Di(2-ethylhexyl) Hydrogen Phosphate

Extraction of rare earth elements with solutions of di(2-ethylhexyl) hydrogen phosphate or tributyl phosphate in heptane, toluene, or tetrachloromethane is accompanied by the origination and development of spontaneous surface convection. The spontaneous surface convection is manifested in the form of interfacial oscillation but can also lead to its break. The spectral composition of spontaneous surface convection in the systems with tributyl phosphate and di(2-ethylhexyl) hydrogen phosphate was studied. The motion of liquid elements is more intense in the system with heptane. The modulus of the surface motion velocity of the liquid elements in the systems with tributyl phosphate is higher than in those with di(2-ethylhexyl) hydrogen phosphate. Local oscillatory action on the interfacial layer at the resonance frequency increases the extraction rate.