Olemedia/E+ via Getty Images Arcadium Lithium (NYSE:ALTM) +38.3% post-market Friday after Reuters reports Rio Tinto (RIO) is in talks to buy the lithium miner, in a deal that would make Rio the third-largest producer of the electric vehicle battery metal. Talks reportedly have been ongoing and continued in London this week during the LME Week conference. Arcadium (ALTM) could be valued at $4B-$6B in a sale, according to the report, which also says an offer is expected in the near future. Arcadium (ALTM) shares already had surged 10% in regular trading after The Australian reported Rio Tinto may be pursuing a major M&A deal in the lithium space. The severe slump in lithium prices, which is due in part to Chinese oversupply, has pushed Arcadium (ALTM) shares down more than 50% since January, making it an attractive takeover target.