Recycling Chlorine: A Recycled Idea
SWIMMERS PLUNGING INTO public pools often feel reassured by a whiff of chlorine. But the chemical is an environmental nightmare. American makers of plastics, paints, and other materials consume 12 million tons of it each year. During production, as much as half of that may combine with hydrogen to form a corrosive waste, hydrogen chloride, which turns into hydrochloric acid when dissolved in water.
Soon, companies may be able to recover the chlorine from waste hydrogen chloride and reuse it, thanks to a refinement of a 130-year-old catalytic technique for cleaving chlorine and hydrogen bonds. The original approach converted only 70% of the hydrogen chloride. And the high costs of handling the hot, corrosive mixtures prevented commercialization. But University of Southern California researchers have broken the catalytic process into two steps that run cooler. Based on 18 months of tests with Carburos Metlicos in Barcelona, USC chemical engineer Ronald G. Minet says they can recover chlorine for just $80 per ton. The chemical costs as much as $250 per ton on the open market. Chemical giant ICI and others have expressed interest.