Mixer-settler operations

Recent work has emphasised the need to consider the combined mixer-settler operation, particularly in metal extraction systems where the throughput may be very large. Thus... 

In the example shown in Fig. 7.6, using an alkylphosphoric acid, about 60 stages are required to give a Co/Ni ratio of about 100. So many stages would be too many for mixer-settler operation, and other types of contactors would have to be considered. In this particular example, a sieve plate pulsed column has been shown to be very effective [3]. Flowever, with the development of the alkylphosphonic and alkylphosphinic acids, the separation of cobalt and nickel can be achieved in very few stages, owing to the high rejection of nickel (see Chapter 11). 

The use of a series of mixer/settlers, operating in countercurrent flow, between -20 and +5 C, at OJ to 0.4.10 Pa, to absorb the butadiene and to achieve the progressive enrichment of the ammonium solution by liquid/liquid contact. Butadiene desorption by heating around 80°C at 0.12.10 Pa. 

The liquid membrane process will become accepted not only when it offers economic advantages over the traditional solvent extraction process but also if sufficient basic information is available for a reliable prediction of its performance. A cost comparison of the liquid membrane process and mixer-settler operation has been conducted for the extraction of uranium and copper (10) and the results are presented in Tables 2 and 3 (SX denotes mixer-settler operation, LM liquid membrane process). 

Liquid solutions, where the solute to be removed is adsorbed relatively strongly compared with the remainder of the solution, are treated in batch, semicontinuous, or continuous operations in a maimer analogous to the mixer-settler operations of liquid extraction (contact filtration). Continuous countercurrent cascades can be simulated or actually realized by use of such techniques as fluidized beds. 

You want to extract 99% of a new anti-inflammatory drug from a dilute reaction mixture. You will do this with mixer-settlers operated countercurrently, using pure solvent feed. The equilibrium line is... 

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