Membrane‐liquid emulsion membrane process using a liquid emulsion membrane process using methane sulfonic acid as a strippant

Abstract

A dvanced extraction proceses, and particularly, the liquid emulsion membrane (LEM) process, have considerable economic .potential in hydrometallurgy operations where an enrichment of the extracted metal is desired despite its low levels of concentration, (Frankenfeld et at., 1981; Weiss and Crigoriev, 1982;Hayworth et at., 1983). The LEM process involves extraction and stripping in one step.The organic emulsion membrane provides a very large interfacial area for the transport of a given component, thereby enhancing the volumetric mass transfer rate. The block diagram of LEM process is depicted in Figure 1.To develop and design the LEM process, it is important to elucidate the role of the stripping agent (hereon referred to as the strippant) in the behavior of LEM. The LEM process, like any other process, has some drawbacks, such as the instability of the membrane due to swelling and breakaqe of the emulsion qlobule. Thus, the selection of a strippant is key to ihe success of the LE?M process. 'Author to whom correspondence m a y be addressed. E-moil address:The application of a liquid emulsion membrane (LEM) process in the recovery of zinc from aqueous solutions is discussed. The role of a stripping agent is very important in the LEM extraction process. Various stripping agents, such as hydrochloric, sulfuric, nitric and methane sulfonic acids, were tested for the stability of membrane. Methane sulfonic acid outperforms the other acids as a strippant. Further importance was given to the stability of the liquid emulsion membrane during the extraction process. The important variables affecting the LEM permeation process of zinc in a mechanically agitated contactor (MAC), such as residence time for extraction, speed of agitation, organic diluents, surfactant concentration and internal strip acid concentration, were systematically investigated. Emulsion swelling and breakage that occurred during these investigations were also described. Finally, the static mixer (SM) device was shown to have a very good potential for LEM extraction of zinc as it outperforms MAC.On a etudie I'application d'un procede de membrane a emulsion liquide (EM) dans la rkup6ra-tion du zinc B partir de solutions aqueuses. Le r61e de I'agent d'bpuisement est tres important dam le procede d'extraction LEM. La stabilite de la membrane a ete testee pour divers agents d'epuisement comme les acides hydrochlorique, sulfurique, nitrique et sulfonique de methane. L'acide sulfonique de methane surpasse les autres acides en tant qu'agent d'epuisement. Une plus grande importance a 6te accordee B la stabilite de la membrane a emulsion liquide lors du procede d'extraction. Les variables jouant un rde important dans le proc6de de permeation LEM du zinc dans un contacteur agite mhniquement (MAC), telles que le temps de sejour pour I'extraction, la vitesse d'agitation, les diluants organiques, la concentration de surfactant et la concentration d'acide d'epuisement interne, ont B e systematiquement etudiees. Le gonflement et la rupture de I'emulsion survenant l...

Selective separation of copper and nickel ions from aqueous solutions containing calcium by emulsion liquid membranes using central composite design

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Liquid Emulsion Membrane (LEM) Process for Vanadium (IV) Enrichment: Process Intensification

“…The increase turbulence level in both phases might result in emulsion formation, which necessitate de-emulsification/coalescence vessel or result in higher residence time in the separation vessel. The liquid emulsion membrane (LEM) process overcomes above deficiencies and results in process intensification by providing interfacial area say, a thousand times and carrying out extraction and stripping operation simultaneously in the same contactor (1).…”