Midrex International, B.v., Rotterdam, Zurich Branch

Kyle J Shoop

David C Meissner

Glenn E Hoffman

Isao Kobayashi

Shoichi Kikuchi

Koji Tokuda

Shuzo Ito

Osamu Tsuge

Akira Uragami

Yasuhiro Tanigaki

Takuya Negami

An apparatus and method for the direct reduction of iron oxide utilizes a hearth furnace having a vitreous hearth layer of conditioning materials, with the vitreous hearth layer introduced onto a refractory surface of the furnace. The vitreous hearth layer may have upper layers of coating compounds including carbonaceous materials, onto which iron oxide feed material is placed with the carbonaceous materials assisting with segregating the reduced molten iron nuggets from the vitreous hearth layer. The conditioning materials may include compounds such as silicon oxide, magnesium oxide, iron oxides, and aluminum oxide. The conditioning materials are placed in solid or liquid form on the refractory surface, which allows the conditioning materials to raise the melting temperature of the vitreous hearth layer onto which the coating compounds and iron oxide materials are placed. The iron oxide materials form molten metal nuggets of high purity iron and residual carbon, which remains separate from the vitreous hearth layer due to the layer of coating compounds. The invented apparatus and method of operation provide a solid iron and carbon product having high iron purity, which is discharged from the furnace without significant loss of iron onto the interior surfaces of the hearth furnace, and with limited buildup of hardened films of metallized iron product within the hearth.

Furnace hearth for improved molten iron production and method of operation

The present invention is an apparatus and method for the direct reduction of iron oxide utilizing a rotary hearth furnace to form a high purity carbon-containing iron metal button. The hearth layer may be a refractory or a vitreous hearth layer of iron oxide, carbon, and silica compounds. Additionally, coating materials may be introduced onto the refractory or vitreous hearth layer before iron oxide ore and carbon materials are added, with the coating materials preventing attack of the molten iron on the hearth layer. The coating materials may include compounds of carbon, iron oxide, silicon oxide, magnesium oxide, and/or aluminum oxide. The coating materials may be placed as a solid or a slurry on the hearth layer and heated, which provides a protective layer onto which the iron oxide ores and carbon materials are placed. The iron oxide is reduced and forms molten globules of high purity iron and residual carbon, which remain separate from the hearth layer. An improved apparatus includes a cooling plate that is placed in close proximity with the refractory or vitreous hearth layer, cooling the molten globules to form iron metal buttons that are removed from the hearth layer. The improvements due to the present apparatus and method of operation provide high purity iron and carbon solid buttons, which are separate from slag particulates, and discharged without significant loss of iron product to the interior surfaces of the furnace.

Iron production method of operation in a rotary hearth furnace and improved furnace apparatus

A method for producing solid metal product is disclosed including the steps of providing carbon and metal bearing compounds in compacts, coating the compacts with treatment materials, encapsulating the compacts with carbonaceous containing materials to form a residual layer, and treating the residual layer before introduction of the compacts into a furnace. The compacts contain carbon containing metal bearing compounds, and are coated with mixtures of carbonaceous materials dispersed within a binder material such as a viscous liquid, molasses, alcohol, or fuel oil. The coated compacts are treated to form a hardened outer residual layer. The outer residual layer provides for a sacrificial outer coating on the compacts that reacts with any oxidizing gaseous components within the furnace, while the carbon containing metal bearing compounds within the compacts are heated and metallized inside the compounds. The outer residual layer provides for improved production of higher purity of metal and carbon nuggets with decreased furnace processing times. Therefore, an increase in purity of the metal product is produced at a lower cost, with minimization of the interaction of the molten metal and slag from nuggets with the furnace hearth surface.

Treatment of iron oxide agglomerates before introduction into furnace

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Pittsburg, PA, United States of America

Kyle J Shoop