May 18 (Reuters) - Compass Minerals plans to jump back into the lithium market by partnering with technology startup EnergyX to extract the battery metal from Utah's Great Salt Lake, a move that comes as prices rise for the critical mineral alongside a broader push to boost U. The companies have signed a memorandum of understanding that, if finalized, would see General Motors-backed EnergyX invest more than $400 million and use its direct lithium extraction (DLE) technology to filt