# US 4,394,163 A · Process for the manufacture of crude iron and synthesis gas

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- Number: US 4,394,163 A
- Document ID: US4394163A
- Status: Granted
- Kind: A
- Application number: 06/275,325
- Filed: 1981-06-19
- Granted: 1983-07-19
- Earliest claimed: 1980-06-23
- Assignees: Asea AB
- Inventors: Per H. Collin
- Web page: https://patentgrep.com/patent/US4394163A

## CPC

- C21B 13/125: {By using plasma}
- Y02P 10/134: by avoiding CO2, e.g. using hydrogen
- Y02P 10/143: of methane [CH4]
- C21B: MANUFACTURE OF IRON OR STEEL (preliminary treatment of ferrous ores or scrap C22B1/00)
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

In a combined process crude iron and a synthesis gas particularly suitable for the preparation of methanol are prepared by supplying iron ore concentrate to the plasma zone between an electrode and a crude iron melt in an arc furnace, while injecting gaseous or volatile hydrocarbons, for example natural gas mainly consisting of methane, into the crude iron melt.

## Claims

### Claim 1

A process for converting an iron oxide into crude iron which comprises: I. introducing in an arc furnace, a fine-grained material essentially containing iron oxide into a plasma zone between an electrode and a melt surface of a crude iron melt, and II. injecting a gaseous or volatile hydrocarbon into said crude iron melt at a depth of at least 30 cm below the surface thereof, comprising:
a.1 preheating the iron oxide-containing material, or said iron oxide-containing material in admixture with adjusted quantities of slag formers, by means of combustion gases from burning the gases from the prereduction according to a.2 or supplementally with other fuels;
a.2 prereducing the preheated concentrate according to a.1;
a.3 introducing the concentrate prereduced according to a.2 in the plasma zone below the electrode in an arc furnace of a direct current type, said furnace containing a crude iron melt, the temperature of said melt, by means of adjused supply of electrical energy to the arc, is maintained over 1200.degree. C., and the content of dissolved carbon in said melt is maintained above 2% by injecting suitably preheated hydrocarbons into the crude iron melt at a depth exceeding 30 cm below the surface of the melt;
a.4 precooling the gases leaving the arc furnace by introducing directly into the leaving gases an adjusted flow of coolant, or a mixture of natural gas and water vapor, and
a.5 recovering a substantial part of the physical heat content of the precooled gases, and purifying from dust said precooled gases by scrubbing.

### Claim 2 (depends on 1)

A process as defined in claim 1 and wherein hydrocarbons are injected at a depth exceeding 50 cm below the surface of the melt.

### Claim 3 (depends on 1)

A process according to claim 1 and wherein the crude iron melt is agitated.

### Claim 4 (depends on 1)

A process as defined in claim 1 characterized in that the gases discharged from the arc furnace, or after adjustment of the ratio H.sub.2 :CO, cooling, and dust precipitation, are used as synthesis gases, such as for preparation of methanol.

### Claim 5 (depends on 1)

A process as defined in claim 1 wherein hydrocarbon natural gas mainly consisting of methane is employed.

### Claim 6 (depends on 1)

A process according to claim 1, and wherein the concentrate is prereduced with gases discharged from a synthesis plant.

### Claim 7 (depends on 1)

A process as defined in claim 1, wherein the recovery of a substantial part of the physical heat content of the precooled gases takes place by heat exchange with air, discharged gases and hydrocarbons.