The formal sale agreement follows the signing of an exclusivity agreement last month.
The deal still remains subject to Foreign Investment Review Board approval and Chinese anti-trust approvals, and Western Australian ministerial consent.
MinRes managing director Chris Ellison said he was pleased to have completed the definitive documentation for the joint venture.
"It is very apparent to me that there is an extremely good fit between the corporate cultures and skill sets of our respective businesses," he said.
"Our proven local West Australian capability is extremely well complemented by Albemarle's proven technical downstream processing expertise and their international marketing capabilities in lithium.
"'Our organisations share the same vision to develop Wodgina, a Tier 1 asset, as a world-class, 30-plus year integrated lithium operation together."
MinRes will be responsible for funding and completing the three 250,000 tonne per annum plant modules, before handing them over to the JV.
The first train is due to start commissioning in the March quarter, followed by the second and third in the June quarters.
Capital costs are forecast at A$229.9 million.
MinRes will provide the JV with crushing services, camp and airport operations and maintenance, and mine-to-port haulage.
A planned 100,000tpa hydroxide plant, to likely be built at Wodgina in two stages, will be jointly funded by MinRes and Albemarle.
Albemarle will manage the marketing and sales of spodumene, and later, hydroxide.
Albemarle is already building its own hydroxide plant at Kemerton, south of Perth, to be fed by its 49% share of production from the Greenbushes mine.
Shares in MinRes rose 4% this morning to $14.87.