Reuters: China’s quest for a green future built on rare earths metals seems a world away from Ren Limin as he casts lumps of one of the metals in a chemical-spattered shed thick with acrid fumes. Ren tends cauldrons of sputtering acid, additives and ore in a shed in north China’s Inner Mongolia region, smelting lanthanum, one of the 17 rare earths that Beijing hopes will power the nation up the clean technology ladder. Yet Ren and a workmate use few safety protections as they stir and poke the red-hot…