The invention concerns a method of utilizing dusts which are produced during the reduction of iron ore with a reduction gas and are deposited in the form of slurries in a scrubber. According to the method the slurries are then dewatered and used as starting material for the production of cement.

Method of utilizing dusts produced during the reduction of iron ore

Disclosed is a method for steel making which includes charging a direct reduction reactor (DRR) with iron ore from a charging system. The iron ore is reduced to hot direct reduced iron (DRI) in the DRR and discharged to rotary kiln(s). The rotary kiln(s) does not process the DRI, but transports the hot DRI to one or more electric arc furnaces (EAF). Top gas (i.e., spent reducing gas) is drawn off of a top section of the DRR. A portion of the top gas is used to pressurize the rotary kiln to prevent air from entering the rotary kiln. Another portion of the top gas flows to a pressure swing adsorber or a vacuum pressure swing adsorber (PSA/VPSA) for CO2 and H2O removal. A cool reducing gas exits the PSA/VPSA. A plasma torch burns natural gas and oxygen to form a hot reducing gas. The hot reducing gas is mixed with the cool reducing gas to form a final reducing gas. The final reducing gas is delivered to the DRR. Also disclosed is a mini-mill to perform the method of steel making.

Integrated mini-mill for iron and steel making

A method of manufacturing hot metal from iron oxide in a shaft furnace by means of reduction with CO and H 2 is described in the case of which iron oxide and coke are placed in the shaft furnace. For the purpose of the coke combustion, oxygen or a gas containing oxygen is introduced together with a reduction gas having a temperature ranging from approximately 1300° to 1500° C., comprising for the most part CO and H 2 and introduced from the hot metal zone of fusion into the furnace shaft. The flue gas of the shaft furnace is purified at least partly, whereby a backflow gas comprising for the most part CO and H 2 is formed and introduced back into the shaft furnace. This method is characterized by the fact that it is especially economical.

Method of manufacturing hot metal

A charge of ore, pellets, sinter and the like is admitted into the top of a shaft furnace. In the upper region of the furnace, there are provided inlets through which a reducing gas is introduced into the furnace. Direct reduction of the charge takes place in the upper region of the furnace and yields iron sponge. The iron sponge forms a column in the furnace which extends from the upper region of the furnace into the lower region of the latter. A burner extends into the lower region of the furnace and continuously directs a flame against the lower end of the sponge column. As the iron sponge in the lower portion of the column melts, fresh iron sponge descends through the furnace and becomes exposed to the flame so that the iron sponge is continuously melted. The molten material is continuously withdrawn from the furnace. The charge may include alloying elements so as to permit alloying of the molten material to produce a steel having a desired composition.

Process for steel production

A method for reducing particulate iron oxide and/or other iron units to molten iron utilizing gaseous hydrogen as reductant in a reducing furnace, in which the ore freely falls during the melting and reduction process Reacted top gas is purified and recirculated through the reduction furnace, establishing a counter-flow relationship to the particulate iron oxide, thereby heating and reducing the oxide The heat for reduction is generated by combusting a fraction of the hydrogen reductant with oxygen Heat may also be supplied via the use of electric arc heating Oxygen may be partially or wholly replaced with water in order to maintain reaction oxidizer ratios while reducing heat supplied to the reaction

Method for reducing particulate iron ore to molten iron with hydrogen as reductant

Molten iron is produced directly from high grade iron oxide ore by the direct reduction in a vertical shaft furnace of preheated ore with hydrogen and carbon monoxide gaseous mixtures. The mixtures of hydrogen and carbon monoxide are adjusted to maintain a continuously increasing H2:CO ratio in the direction the charge passes through the vertical reduction zone while maintaining about the same temperature, below about 1,100* C., throughout the entire reduction zone.

H. Blanck Joachim

Papers

Direct gaseous reduction of iron oxide