Method and apparatus removing undesirable metals from iron-containing materials

Abstract

The present invention relates to a method and apparatus for separating undesired toxic metals, such as Zn, Pb and Cd, from iron-containing materials by: sintering a mixture of such materials (typically including EAF dust and mill scale) with carbonaceous particles to form sturdy sinter lumps; preheating such lumps in a non-reducing atmosphere, if needed, to achieve an elevated temperature generally above the vaporization temperature of the undesired metals, but below the sticking temperature of iron-containing lumps (which is typically below the vaporization temperatures of such undesired metals in their oxide form), feeding the lumps at such elevated temperature into a reduction reactor; flowing hot reducing gas through lumps to volatilize undesired reduced metals and carry the volatilized metals out of reduction reactor leaving the iron-containing lumps largely stripped of the undesired metals and ready for discharge and safe and/or useful disposal or re-use, and finally cooling the off gas from the reactor to separate out the resulting solidified unwanted metals (typically in their oxide form resulting from a water quench cooling).