Neometals (ASX:NMT) said that Reed Advanced Materials agreed with Livent USA, a unit of the Rio Tinto Group (ASX:RIO), to extend the term of their memorandum of understanding establishing a non‑binding framework for Reed and Rio Tinto to collaborate on validating and advancing Reed's lithium processing technology, according to a Thursday Australian bourse filing.

Reed is 70:30 co-owned by Neometals with Mineral Resources (ASX:MIN).

The process includes optimization test work, process‑design updates, and field trials on Rio Tinto's lithium brine assets, the filing said. The memorandum had an initial term of eight months, and the companies agreed to extend it for a further 12 months.

This will allow time for the completion of testing of new brine feedstock from Rio Tinto's existing brine operations, and the incorporation of Industrie De Nora and its unit, De Nora Permelec, into the ELi Process pilot-scale validation program, including integration of De Nora's electrolysis equipment into Reed's process flowsheet, the filing said.

Neometals' shares fell past 3% in recent trading on Thursday, while Rio Tinto's shares shed about 1%.