Calix (ASX:CXL) restarted the development of the midstream demonstration pilot plant project in partnership with Pilbara Minerals (ASX:PLS), according to a Wednesday Australian bourse filing.

The restart followed a AU$15 million grant funding from the state government of Western Australia which will be used to reduce the construction costs of the partners in the venture, the filing said.

Construction and commissioning are slated for completion in the December quarter.

The project is designed to demonstrate the potential of lower cost of electrification and lower carbon in lithium processing.

The firm's shares soared 19% on market close on Thursday.