Separation Of Copper,Nickel And Cobalt From Ammonia Medium Using Supported Liquid Membrane

High efficient separation of copper,nickel and cobalt has been a hot topic of metallurgy due to they always associated existence in mineral deposit and similar physicochemical properties.Ammoniacal leaching supports selective extraction of copper,nickel and cobalt as their ammine complexes,and simultaneously separates them from a mass of calcite and magnesia in order to avoid subsequent purification in hydrometallurgy.In this paper,separation of copper,nickel and cobalt from ammonia-ammonium chloride medium by supported liquid membrane containing Acorga M5640 was investigated through simulating of ammoniacal leaching system.Three ions could be separated with each others using different methods.Then,the influences of experimental variables on metal ion transfer and separation,such as stirring speed,carrier concentration,the H2SO4 concentration of stripping phase and so on were studied.1.Copper and nickel were co-extracted by Acorga M5640,but they can be separated after adding TRPO into Acorga M5640.In the supported liquid membrane,almost all of copper were transfered into the stripping phase after 12 h with a permeability coefficient of 1.56×10-5 m/s under the conditions:100 Mg/L each of the copper and nickel dissolved in 1.0 mol/L each of ammonia and ammonium chloride solution as feed phase,stirring speed of 1000 rpm,20 vol.%Acorga M5640-10 vol.%TRPO-kerosene as the carrier and 50 g/L H2SO4 in the stripping phase.While 90.6%of nickel were left in feed phase,and the separation coefficient of copper and nickel reaches 10.64.2.Cobalt could not be extracted by Acorga M5640 after that bivalent cobalt was oxidized into trivalence in ammonia solution,so nickel and copper can be separated over cobalt.In the supported liquid membrane,96.8%of nickel were transfered into the stripping phase after 16 h with a permeability coefficient of 9.31×10-6 m/s under the conditions:100 mg/L each of the nickel and cobalt dissolved in 1.0 mol/L each of ammonia and ammonium chloride solution as feed phase,stirring speed of 1000 pm,20 vol.%Acorga M5640-kerosene as the carrier and 10 g/L H2SO4 in the stripping phase.While the transfer rate of cobalt is only 1.8%,and the separation coefficient of nickel and cobalt reaches 80.67.In addition,almost all of copper were transferted from the feed fase to the stripping phase after 12 h with a permeability coefficient of 1.94×10-5 m/s under similar conditions.Only 0.8%cobalt was transferred into the stripping phase,the separation coefficient of copper and cobalt reaches 125.3.The Sandwich supported liquid membrane model was designed and used to simultaneously separate of copper,nickel and cobalt in ammonia-ammonium chloride medium.When the concentration of copper,nickel and cobalt both are 100 mg/L,and the concentration of ammonia and ammonium chloride both are 1 mol/L in the mixed feed fase,the 99.5%of cobalt,98%of nickel and 98.9%of copper were separated to three different compartments after 36 h under the conditions:stirring speed of 1000 rpm,20 vol.%Acorga M5640-kerosene as the carrier in two membranes,10 and 50 g/L H2SO4 in two stripping phases.4.The mass transfer dynamics model of nickel ion through supported liquidmembrane(P= 9.3×104+8.74×103/[HL]2)-1was presented by Fick first law.The factorscaused instability and the prospect of new supported liquid membrane was discussed.