On the application of liquid-membrane principle in a system of mixing-settling extractors

The paper is devoted to the possibilities of applying the liquid-membrane technique in extraction processes in a cascade of mixing-settling apparatuses. The process is performed in the cascade of N mass-exchange stages, each of which contains two mixing-settling extractors, one of which is used in the extraction of a component from the starting water solution, while the other is used in the its reextraction by the second (pure) water solution. Calculation dependences between the input and output concentrations in flows are represented. Experimental investigations were carried out on a laboratory plant consisting of eight glass cylindrical mixing-settling apparatuses with a standard extraction system water-acetone-toluene at two schemes of the stage assemblage: with the internal (between the stages of extraction and reextraction) and external (extractant flow passes first through all extraction stages and next reextraction those) extractant circulation. The efficiency of the first variant (liquid membrane scheme) was found to be two times higher than that of the second variant.