A Multi-Stream Microchip for Process Intensification of Liquid-Liquid Extraction

Solvent extraction is a critical step in many industrial mineral-processing circuits and is affected by chemical (e.g., metal ions, extractant, pH, reaction rate) and physical (e.g., interfacial phenomena, mass transport, temperature) factors. Here, a new type of microfluidic contactor is presented that enables higher volumetric throughputs and straightforward counter-current operation compared with Y-Y chips. A single chip design can handle a wide range of organic/aqueous phase ratios, thereby enabling stable operation for non-ideal solutions and fluctuating flow. An expression defining this widened operational window has been derived based on the relative stream geometries and liquid viscosities. A two-stage counter-current circuit is demonstrated for the extraction of platinum(IV) chloride.