MOUND HOUSE (AP) - A fire at a plant in Mound House didn't get the usual water-hosing - crews say it took the chemical argon to put out the flames.Bob Kielty of the Central Lyon County fire district says nobody was injured when the fire broke out about 4 a.m. Friday at the Kemet plant in Mound House. The company produces a metal called tantalum, which is used in electronics.Kielty says workers were reducing solid sodium into tantalum when some of the sodium got out of a boiler and started a fire.Officials say about 15 employees evacuated, and a built-in …