The refinery, located on Teeside, is intended to produce up to 2,810tpa of neodymium praseodymium oxide and is expected to cost US$160 million to construct.
"The Teesside location provides a major competitive advantage with its "plug and play" infrastructure, skilled labour force and proximity to potential customers, while its freeport status provides tangible tax and other benefits," said Peak's managing director Bardin Davis.
A bankable feasibility study was completed on Ngualla in 2017.
However, the Ngualla project has been stuck in licencing limbo for four years and cannot advance until Peak is granted a special mining licence (SML) by Tanzania's government.
Davis told Mining Journal in April that Peak was "very well positioned to secure that approval in the not too distant future", following positive noises from Tanzania's new president.
The company plans to update its BFS once it has secured the SML.