CA2630236A1 - Method for manufacturing metallic iron - Google Patents

Abstract

A process for producing metallic iron from a charge stock mixture containing a carbonaceous reducing agent and an iron-oxide-containing substance, characterized by including the steps of determining, corresponding to a preselected target carbon concentration in metallic iron, a target formation temperature of an initial molten slag first formed in the charge stock mixture by heating the charge stock mixture, the initial molten slag containing gangue components, unreduced iron oxide and ash of the reducing agent; preparing the charge stock mixture for forming of the composition of the initial molten slag corresponding to the target formation temperature; and heating the charge stock mixture to thereby accomplish not only reduction/melting of the charge stock mixture but also forming of the initial molten slag. The metallic iron having the target carbon concentration can be efficiently produced by this process.

Claims (10)

1. A method for manufacturing metallic iron from a raw material mixture containing a carbonaceous reducing agent and an iron oxide-containing material, comprising:

a step of determining a target temperature of initial molten slag formation corresponding to a predetermined target carbon concentration in the metallic iron, the initial molten slag containing a gangue component, an unreduced iron oxide, and an ash component of the carbonaceous reducing agent, and being first produced in the raw material mixture by heating thereof;

a step of preparing the raw material mixture producing a composition of the initial molten slag corresponding to the target temperature; and a step of heating the raw material mixture to reduce and melt the raw material mixture and to produce the initial molten slag.

2. The method according to Claim 1, wherein in the preparation step, a slag-forming component is mixed with the iron oxide-containing material.

3. The method according to Claim 1 or 2, wherein in the preparation step, a slag-forming component is mixed with the carbonaceous reducing agent.

4. The method according to one of Claims 1 to 3, wherein the raw material mixture further contains an additional raw material, and in the preparation step, a slag-forming component is mixed with the additional raw material.

5. The method according to one of Claims 1 or 4, further comprising a step of charging an additive containing a slag-forming component before the heating step.

6. The method according to one of Claims 1 to 5, wherein in the heating step, a slag-forming agent containing a slag-forming component is added.

7. The method according to one of Claims 1 to 6, wherein the target temperature is determined by a multi-component phase diagram composed of a gangue component, unreduced iron oxide remaining in reduction, and an ash component of a carbonaceous reducing agent.

8. The method according to one of Claims 1 to 7, wherein a relationship between a temperature forming the initial molten slag and a carbon concentration in the metallic iron is evaluated beforehand, and the target temperature is determined by the target carbon concentration in accordance with the relationship.

9. The method according to one of Claims 1 to 8, further comprising, before the heating step, a step of setting a target content of the unreduced iron oxide in the initial molten slag and calculating a target reduction degree of the iron oxide-containing material corresponding to the target content, wherein in the heating step, until a reduction degree of the iron oxide-containing material reaches the target reduction degree, a heating temperature pattern or a reduction potential is adjusted, and simultaneously heating is performed.

10. The method according to one of Claims 1 to 9, wherein in the heating step, heating is performed based on a melting point of slag containing unreduced iron oxide in reduction.