OPTIMIZED MELTING OF COMPACTED DRI

Abstract

A method for melting DRI consisting at least partly of HBI and/or HCI using a melting process, wherein the HBI and/or the HCI is comminuted before being supplied to the melting process, and HBI or HCI fragments obtained during the comminuting process are supplied to the melting process.

Claims

1-5. (canceled)

6. A method for melting sponge iron (DRI) consisting entirely of at least one of hot-briquetted sponge iron (HBI) and hot-compacted sponge iron (HCI), comprising: comminuting the at least one of the hot-briquetted sponge iron (HBI) and the hot-compacted sponge iron (HCI) prior to being supplied to a melting process; wherein fragments of the at least one of the hot-briquetted sponge iron (HBI) and the hot-compacted sponge iron (HCI) obtained during comminution are supplied to the melting process.

7. The method as claimed in claim 6, wherein the comminution is a crushing operation.

8. The method as claimed in claim 7, wherein the crushing operation is performed in at least two stages.

9. The method as claimed in claim 6, wherein the comminution is to a size of the fragments within a range of from 3.35 mm to 31.5 mm.

10. The method as claimed in claim 9, wherein the comminution is to the size of the fragments within another range of from 3.35 mm to 25 mm.

11. The method as claimed in claim 10, wherein the comminution is to the size of the fragments within a further range of from 6.3 mm to 16 mm.

12. The method as claimed in claim 6, wherein the melting process comprises at least one of the following methods: melting in an electric arc furnace (EAF); melting in a submerged arc furnace (SAF); melting in an open slag bath furnace (OSBF); melting in a melting unit; and melting in a converter vessel.

13. The method as claimed in claim 6, wherein: a minimum size is defined for the fragments formed during comminution; and the fragments formed during comminution that are below the minimum size are removed.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The above-described properties, features, and advantages of this invention and the manner in which they are achieved will become clearer and more clearly comprehensible in conjunction with the following description of embodiments, which are elucidated more particularly in conjunction with the schematic and exemplary drawings. In the figures:

[0043] FIG. 1 illustrates schematically the execution of an embodiment of the method of the invention with HBI.

[0044] FIG. 2 illustrates schematically the execution of an embodiment of the method of the invention with HCI.

DETAILED DESCRIPTION

[0045] FIG. 1 shows how DRI 20, in the present case HDRI, produced in a reduction unit 10 based on direct reduction in a fixed bed or fluid bed or fluidized bed is compacted into HBI 40 in a briquetting device 30. The HBI is supplied to a melting process in a melting device 50, optionally after transport to another site, for example by rail or by ship. The melting device is for example a device suitable for performing one of the group of methods consisting of [0046] melting in an electric arc furnace (EAF), [0047] melting in a submerged arc furnace (SAF), [0048] melting in an open slag bath furnace (OSBF), [0049] melting in a melting unit [0050] melting in a converter vessel.

[0051] Upstream of the supply, which in the example shown takes place via an intermediate bunker 60, but can also take place directly, i.e. without an intermediate bunker, the HBI 40 is crushed in the comminution device 70, which can be single-stage or multistage, for example two-stage. In the example shown, the comminution device is a crusher. Fragments of the HBI 40 obtained during comminution are supplied to the melting device 50 via the intermediate bunker 60.

[0052] FIG. 2 shows how DRI 90, in the present case HDRI, produced in a reduction unit 80 based on direct reduction in a fluid bed or fluidized bed is compacted into HCI 110 in a compacting device 100. The HCI 110 is then supplied to a melting process in a melting device 120, where appropriate close to the site of compaction in a plant network. The melting device is for example a device suitable for performing one of the group of methods consisting of [0053] melting in an electric arc furnace (EAF), [0054] melting in a submerged arc furnace (SAF), [0055] melting in an open slag bath furnace (OSBF), [0056] melting in a melting unit, [0057] melting in a converter vessel.

[0058] Upstream of the supply, which in the example shown takes place via an intermediate bunker 130, but can also take place directly, i.e. without an intermediate bunker, the HCI 110 is crushed in the comminution device 140, which can be single-stage or multistage, for example two-stage. In the example shown, the comminution device is a crusher. The fragments 150a, 150b of the HCI 110 that are obtained during comminution are sieved in a sieving device 160. Only the fragments 150a above a minimum size are supplied to the melting device 120 via the intermediate bunker 130. The fragments 150b below the minimum size are supplied to the compacting device 100, where they are compacted together with HDRI.

[0059] Although the invention has been illustrated and described more particularly by the preferred exemplary embodiments, the invention is not limited by the examples disclosed and other variations can be derived therefrom by a person skilled in the art without departing from the scope of protection of the invention.

LIST OF REFERENCE NUMERALS

[0060] 10 Reduction unit [0061] 20 DRI [0062] 30 Briquetting device [0063] 40 HBI [0064] 50 Melting device [0065] 60 Intermediate bunker [0066] 70 Comminution device [0067] 80 Reduction unit [0068] 90 DRI [0069] 100 Compacting device [0070] 110 HCI [0071] 120 Melting device [0072] 130 Intermediate bunker [0073] 140 Comminution device [0074] 150a,150b Fragments [0075] 160 Sieving device