Recycling process for recycling granulated metallic materials containing surface impurities

Abstract

The present invention relates to a recycling process for recycling granulated metallic materials containing surface impurities combining a subprocess 1 and a subprocess 2, where the contaminating material is partially removed in subprocess 1 by means of heating the starting material to a temperature less than or equal to 300° C. in a controlled oxidizing atmosphere; and the material is heated to 400-550° C. in an inert atmosphere in subprocess 2 and the remaining residues of contaminating material are removed by a combined thermal-mechanical action.

1 . A process for recycling granulated metallic materials containing surface impurities, the process comprising:
 combining a subprocess  1  and a subprocess  2 ;   wherein a contaminating material is partially removed in subprocess  1  by means of heating a starting material to a temperature less than or equal to 300° C. in a controlled oxidizing atmosphere; and   wherein the starting material with the contaminating material partially removed is heated to 400-550° C. in an inert atmosphere and the remaining residues of contaminating material are removed by a combined thermal-mechanical action in subprocess  2 .   
     
     
         2 . The process according to  claim 1 , wherein the starting material is kept in motion during subprocess  1  and the starting material with the contaminating material partially removed is kept in motion during subprocess  2 . 
     
     
         3 . The process according to  claim 1 , wherein the material coming from subprocess  2  is a granulated clean metal suitable for being used as a secondary raw material in industrial applications. 
     
     
         4 . The process according to  claim 1 , wherein the process is completed by subjecting a decontaminated granulated metal originating from subprocess  2  to a sintering process, wherein the sintering process comprises heating the decontaminated granulated metal to a temperature less than a melting point of the decontaminated granulated metal, wherein the decontaminated granulated metal adopts a semi-solid state for being pressed subsequently into the form of briquettes, said sintering process taking place in a subprocess  3 .