LEWATIT® TP 272

Lewatit® TP 272 is a crosslinked polystyrene based macroporous solvent impregnated resin (SIR) which contains bis-(2,4,4-trimethylpentyl-) phosphinic acid. This liquid extractant is directly incorporated during the formation of the copolymer. It was preliminary developed for nickel electrolyte purification (cobalt extraction from nickel solution). Generally it can be assumed that ions which can be removed with bis-(2,4,4-trimethylpentyl-) phosphinic acid will also be adsorbed by Lewatit® TP 272. The selectivity order for the extraction of cations from sulfate containing solutions can be assumed as follows:

Fe3+ > V4+ > Zn2+ > Al3+ > Cu2+ > Mn2+ > Co2+ > Mg2+ > Ca2+ > Ni2+

Advantages of this product compared to conventional solvent extraction are:

• Higher efficiency for the removal of trace impurities and less costs
  Very low leakage of the cations to be removed
• No organic solvent for the dilution of the liquid extractant is required
• No phase separation problems
• Simple equipment similar to conventional ion exchange resins with a smaller plant footprint

• Exposure to any alkaline media (e.g. sodium/potassium hydroxide or sodium/potassium carbonate) should be avoided because the active ingredient might be washed out. It is crucial to maintain the pH
  below 6 at all times (even during backwash and rinsing operations)!
• Since the resin density is lower than water it tends to float. Therefore, the resin layer is recommended to
  be covered by inert material (e.g. Lewatit® IN 42).