Lewatit® TP 272 is a crosslinked polystyrene based macroporous resin which contains bis-(2,4,4-trimethylpentyl-) phosphonic acid. This liquid extraction agent is directly incorporated during the formation of the copolymer, fixed by adsorption and homogenously distributed within the bead in high concentration. Generally it can be assumed that ions which can be removed with bis-(2,4,4-trimethylpentyl-) phosphonic acid will also be adsorbed by Lewatit TP 272. However, it is preliminary designed for the following application:- Nickel electrolyte purification (cobalt extraction from nickel solution)
Moreover, the Lewatit TP 272 also extracts other metal cations and can be used for various other applications. The selectivity order fro the extraction of cations from sulfate containing solutions can be set as follows: Fe3>V4>Zn2>Al3>Cu2>Mn2>Co2>Mg2>Ca2>Ni2 Advantages of Lewatit TP 272 compared to solvent extraction are:- No organic solvent for the dilution of the liquid extractant is required
- No phase separation problems
- Simple equipment similar to conventional ion exchange resins
- Very low leakage of the cations to be removed due to sharp plug flow exhaustion along the direction of flow
Advice:- No activation prior to use is required because the active ingredient of the shipped resin is already in the form of its free acid.
- Exposure to any alkaline media (e.g. sodium/potassium hydroxide or sodium/potassium carbonate) should be avoided because the active ingredient might be rinsed. It is crucial to maintain the pH below 6 at all times (even during backwash and rinsing processes)
- since the resins density is lower than water it tends to float to the water surface. Therefore, the resin layer is recommended to be covered by inert material (e.g. Lewatit IN 42) and to be used in columns with strainers at the bottom and at the top. Loading should be done up flow and regeneration down flow.
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