MISA's Romelt process is a simple, one-step process for direct iron smelting (Table IV). It has been proven capable of smelting a wide range of ores and metallurgical waste materials. It utilizes simple coal fines as both the fuel and the reductant. Because there is no pre-reducer, Zn bearing materials are perfectly acceptable as a feed material. Essentially all of the zinc becomes reduced to metallic Zn vapor, which then escapes and reoxidized to ZnO in the fine dust of the offgas cleaning system. This dust either can be recycled for further concentration of Zn or directed to a Zn recovery operation, if the Zn level is sufficiently high. All of this is accomplished in a process that relies on the use of a large volume, highly agitated slag as both the heat transfer and containment medium (Table V). The process uses minimal refractories as most of the reactor is composed of slag-coated, water-cooled panels. The process operates under slight negative pressure, which greatly contributes to its simplicity of design. Capital equipment costs are estimated to be much lower than any presently utilized or proposed alternatives.
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