| 摘要 |
<p>PURPOSE:To recover a good-quality steel sheet scrap for a melting raw material as the main product and metallic zinc as the by-product by preheating a galvanized steel sheet scrap and then heating the scrap to a specified temp. in a specified vacuum to vaporize and separate zinc, which is cooled and solidified. CONSTITUTION:A galvanized steel sheet scrap is preheated to 400-450 deg.C at atmospheric pressure to remove depositing oil, moisture, dust, etc. The preheated scrap is then heated to 500-900 deg.C in a vacuum at 0.16Torr. Consequently, the zinc is not liquefied but vaporized, and the scrap and zinc are separated. The vaporized zinc is cooled and solidified at <=400 deg.C from the vapor phase to the solid phase while keeping the vacuum. As a result, the devices are not corroded by liq. zinc, zinc is removed from the scrap, the scrap as the main product is recycled as a good-quality melting raw material, and metallic zinc is recovered as the by-product.</p> |
