摘要 |
<p>The invention relates to a method for the heat treatment of residues containing heavy metals, carried out in a multiple-hearth furnace which is divided into three zones, each of which comprises several stacked levels. Said method consists of the following steps: continuous feeding of the heavy-metal residues into the top level of the first zone of the multiple-hearth furnace, the residues being gradually transferred to the second zone and dried during the transfer; continuous feeding of reducing agents and desulfurizers into the top level of the second zone, whereby the reducing agents and desulfirizers are mixed with the dried residues and the mixture is heated to approximately 800° C., calcined during heating and gradually transferred to the third zone; heating of the mixture to approximately 1000° C. in the third zone, whereby the metals are reduced and the waste gases resulting in said third zone are drawn off and treated separately; and discharge of the mixture from the multiple-hearth furnace.</p> |