The move is part of the company's efforts to increase its footprint beyond beyond Burundi, where it runs the continent's only producing rare earths mine.
Under a new supply deal signed with Freeport-McMoRan, major Chinese smelters have accepted the lowest processing fees to turn mined ore into finished metal seen since 2011.
Before the 2011 Arab Spring uprising, Tunisia was one of the world’s largest producers of the fertilizer component, creating as much as 8.2 million tons per year.