One of the best ways to improve engine efficiency and reduce emissions is to make cars lighter. That's often achieved by replacing metal parts with plastics. Trouble is, many plastics are notoriously hard to recycle. At the moment, portions of dashboards, seat covers, and floor mats that contain certain harmful compounds must be segregated and treated with chemicals before petroleum derivatives can be recovered from them.
Now, Mazda Motor Corp. has a way to skip the costly presorting. First, the various plastic parts are vaporized together at a high temperature to produce a gas. Then, the gas is exposed to a catalyst made of metallic salts, which break the molecules down further for refining into gasoline and kerosene. Other companies have experimented with similar catalysts. But most have proved ineffective if the plastic contains polyvinyl chloride or other forms of chlorine. Mazda says its catalyst eliminates this problem but won't reveal its exact composition until more tests are done.