METHOD FOR SUPPLYING RAW MATERIAL TO A SINTER PLANT

Abstract

A method for supplying raw material to a sinter plant and facilitating a sinter process with reduced consumption of fossil fuels, provides that a mixed material is used to supply raw material, wherein the mixed material includes particulate iron-containing material and particulate pyrolised biomass in mixed form. The iron-containing material is preferably iron ore and/or the pyrolised biomass is preferably charcoal.

Claims

1. A method for supplying raw material to a sinter plant, wherein a mixed material is used to supply raw material, wherein the mixed material comprises particulate iron-containing material and particulate pyrolised biomass in mixed form.

2. The method according to claim 1, wherein said mixed material is transported over a long distance, said long distance being 100 km, preferably at least 500 km.

3. The method according to claim 1, wherein said mixed material is transported over a long distance by train or ship.

4. The method according to claim 1, wherein the mixed material is used in the form of compound bodies, wherein each compound body is solid and coherent and comprises particulate iron-containing material and pyrolised biomass.

5. The method according to claim 4, further including prior to supplying the raw material: providing particulate iron-containing material and particulate pyrolised biomass; mixing at least the iron-containing material and the pyrolised biomass to obtain a mixture; and forming the compound bodies from the mixture.

6. The method according to claim 5, it further comprising the step of providing at least one binder and the mixture is obtained by mixing at least the iron-containing material, the pyrolised biomass and the at least one binder said binder comprising organic binder or mineral binder.

7. The method according to claim 4, wherein the agglomerates are formed by briquetting.

8. The method according to claim 1, wherein the mixed material is supplied in bulk form to the sinter plant.

9. The method according to claim 1, wherein the mixed material comprises at least 1 wt.-% of pyrolised biomass, and at least 20 wt.-% of iron-containing material.

10. The method according to claim 1, wherein the mixed material comprises 1 wt.-% of pyrolised biomass and at least 30 wt.-% of iron-containing material.

11. The method according to claim 1, wherein the volumetric proportion of the particulate iron-bearing material in the mixed material is between 5 and 80 vol %.

12. The method according to claim 1, wherein the particulate pyrolised biomass has a D90 sieve size below 10 mm.

13. The method according to claim 1, wherein the particulate iron-containing material comprises sinter feed particles, which have a sieve size at least mostly between 0.1 mm and 6.3 mm.

14. The method according to claim 1, wherein the particulate iron-containing material comprises pellet feed particles, which have a sieve size at least mostly below 0.15 mm.

15. The method according to claim 1, wherein the compound bodies have a maximum dimension between 1 mm and 500 mm.

16. The method according to claim 1, wherein the compound bodies are fragmented before being used in the sinter plant.

17. The method according to claim 1, wherein the mixed material provides at least 10 wt.-% of the iron-containing material and at least 5 wt.-% of the carbon-containing material for a sintering process in the sinter plant.

18. The method according to claim 1, wherein said iron-containing material is iron ore and/or said pyrolised biomass is charcoal and/or said compound body is an agglomerate or a conglomerate.

19. A method of operating a sinter plant, wherein iron-containing material and carbon containing material are supplied to said sinter plant, and they are heated in a furnace to support a sinter process in order to form solid iron containing products, wherein the sinter plant is supplied with mixed material according to the method of claim 1.

20. The method according to claim 19, wherein the mixed material is a bulk mixture of particulate iron-containing material and particulate pyrolised biomass.

21. The method according to claim 19, wherein the mixed material comprises agglomerates of particulate iron-containing material and particulate pyrolised biomass.

22. The method according to claim 19, wherein the sinter plant is configured as a sintering plant, the mixed material being optionally crushed and/or combined with additional components, and optionally agglomerated, before being fired in a furnace under an oxidizing atmosphere, and crushing the resulting sinter product.

23. The method according to claim 19, wherein the sinter plant is configured as a pelletizing plant, the method comprising the steps of, at the sinter plant, grinding the mixed material and forming therefrom iron ore green pellets, and charging and firing said green pellets in an indurating furnace under an oxidizing atmosphere to form hardened pellets.

24. The method according to claim 23, wherein the mixed material and additional material including binder material are ground at a crushing unit of the pelletizing plant, and green pellets are formed from the grinded materials.

25. The method according to claim 24, wherein the mixed material and additional material including binder material are ground at a crushing unit of the pelletizing plant to a particle size of D80<0.045 mm, and green pellets are formed from the grinded materials into spheres of about 6 to 16 mm diameter.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Preferred embodiments of the disclosure will now be described, by way of example, with reference to the accompanying drawings, in which:

[0039] FIG. 1 is a material flow diagram illustration of a method according to a first embodiment of the present disclosure related to a sintering plant;

[0040] FIG. 2 is a process flow chart of the method from FIG. 1;

[0041] FIG. 3 is a material flow diagram illustration of a method according to a first embodiment of the present disclosure related to a pelletizing plant;

[0042] FIG. 4 is a process flow chart of the method from FIG. 3

[0043] FIG. 5 is a material flow diagram illustration of a method according to a second embodiment of the present disclosure related to a sintering plant; and

[0044] FIG. 6 is a process flow chart of the method from FIG. 5.

[0045] FIG. 7 is a material flow diagram illustration of a method according to a second embodiment of the present disclosure related to a pelletizing plant; and

[0046] FIG. 8 is a process flow chart of the method from FIG. 7.

DETAILED DESCRIPTION OF THE DRAWINGS

[0047] FIG. 1 is a material flow diagram illustrating a first embodiment of the inventive method applied for a sintering plant, while FIG. 2 is a process flow chart of this method. The method will now be explained with reference to both figures. In a first step of the method, at 100, particulate iron-containing material iron ore 1, particulate pyrolised biomass charcoal 2 and a binder 3 are provided. For the sake of simplicity, the present description will use iron ore 1 as iron-containing material 1 and charcoal 2 as pyrolised biomass 2. This is however not to be understood as limiting.

[0048] The particulate iron ore 1 is provided from an iron-containing material source such as e.g. an ore mine 5, while the particulate charcoal is provided from a charcoal plant 6. In this embodiment, the particulate iron ore 1 comprises sinter feed, having a particle size between 1 and 6.3 mm, as well as pellet feed, having a particle size below 1.5 mm. Alternatively, it would be possible to use only sinter feed or pellet feed, respectively. The charcoal 2, which may have been produced by slow pyrolysis of plant material, e.g. wood, may have a D90 sieve size below 3.5 mm. The charcoal particles may have a relatively high carbon content, e.g. above 65 wt.-%, above 70 wt.-% or even above 75 wt.-%. The binder 3 can be a mineral binder like bentonite or an organic binder like sugarcane molasses. It could also be a combination of a mineral binder and an organic binder.

[0049] In a next step, at 110, the particulate iron ore 1, the particulate charcoal 2 and the binder 3 are mixed to form a mixture. The mixture may also comprise at least one liquid component, which may be part of the binder 3 or which could be added to facilitate the mixing process. From this mixture, agglomerates 7 are formed (at 120) in an agglomerating unit 4, in which mixing may also be carried out. The agglomerating unit 4 may be disposed close to or even at the charcoal plant 6, in order to minimize the transport distance for the charcoal 2. If more convenient, however, it may also be conceivable to place the agglomerating unit 4 close to the iron ore mine or the shipping harbor. Optionally, the formed agglomerates 7 may be subjected to an elevated temperature to cure the binder 3 or to evaporate liquid components. The agglomerates 7 thus formed comprise particulate iron ore 1, particulate charcoal 2 and the binder 3, which may possibly be chemically altered from its initial form by a curing process or the like. The agglomerates 7 may be e.g. cuboid with a maximum dimension of 10 cm.

[0050] The agglomerates 7 in their finished state represent solid, coherent compound bodies that are well suited for storage and transport. In particular, since the charcoal 2 is bound in the agglomerates, they necessitate no special safety precautions and the inflammation risk associated with pure charcoal 2 is mostly eliminated. The finished agglomerates 7 are transported (at 130) by a first land transport 11 (e.g. by railway or truck) to a first harbour 12, where they are transferred to a ship for a long-distance overseas transport 13 (at 140). Optionally, the first land transport 11 may be unnecessary, if the briquetting unit is near the first harbour 12. After the ship has reached its destination, a second harbour 14, the agglomerates 7 are unloaded and transferred again. Subsequently, they may be transported by another land transport 15 (at 150) to a steel plant 16 that comprises a crushing unit 17 and a sinter plant 20. As a preparation for the use in the sinter plant 20, the agglomerates 7 are crushed (at 160) in a crushing unit 17, whereby a mixture of smaller particles as crushed material 18 is obtained. In some cases, crushing may be omitted, e.g. if the size of the agglomerates 7 is very small. Most of this crushed material 18 will be pure iron ore particles or pure charcoal particles, normally with at least small amounts of binder, while other particles could comprise at least one charcoal particle bound together with an iron ore particle. There could be a dedicated bin (not shown) in the stock house of the sinter plant 20 where the agglomerates 7 are stored. They can then be dosed, crushed and put on a conveying system (e.g. belt conveyor) feeding the mixing drum or the like of the sinter plant 20. Alternatively to the addition of the mix material in the stock house of the sinter plant, they can also be added further downstream or upstream directly in the sinter mix bedding pile.

[0051] The crushing unit 17 can be disposed relatively close to the sinter plant 20 and special precautions can be taken for the transfer of the crushed material 18 from the crushing unit 17 to the sinter plant 20 to avoid any problems with dust generation or inflammation risk associated with the charcoal particles. Additional components 19 are added at 170, which may comprise e.g. pellet feed and/or sinter feed to supplement the iron ore from the agglomerates 7, fossil fuel like anthracite and/or coke breeze, non-fossil fuel or a combination of both to complete the energy requirement for the sintering process, lime, water or other suitable additives. Then, a sinter bed is formed at 180 and sintering is performed at 190. It is worth noting that the crushed material 18 may be fed to a stock house for mixing with the additional components 19. Alternatively, the crushed material 18 may be added directly to the sinter bed. The charcoal from the agglomerates 7 may represent all of the fixed carbon-containing material for the sinter process. Normally though, it represents only a portion, e.g. between 20 wt.-% and 90 wt.-%, of the carbon-containing material. Either way, the amount of fossil fuel is greatly reduced if not eliminated, wherefore the sinteri process is close to CO.sub.2 neutral. As a result of the sinter process, a sinter product 21a with a defined quality is delivered at 200, which in turn can be used for steelmaking in a blast furnace, direct reduction and/or electric furnace or the like.ln the same context of the first embodiment of the inventive method, FIG. 3 illustrates a material flow diagram, where at the second location 31, the compound mix 7, is introduced into a sinter plant 20, having pellet as a product 21b, instead of sinter product 21a, while FIG. 4 is the corresponding process flow chart of this method. The two inventive methods of the first embodiment are alike, with the main difference that all components for the sintering, the additional material 19 and crushed material 18 or the compound body, agglomerate 7 have to be fragmented further, more specifically grinded 171. All components are then ground at a crushing unit 17, typically to a particle size of D80<0.04 mm, and pellets are formed 180, spheres of typically 6-16 mm diameter, before the sintering can be performed 190. After the sintering is performed 190, the pellet product 21b of a defined quality is delivered at 200, which in turn can be used for steelmaking in a blast furnace, direct reduction and or furnace electric furnace or the like.

[0052] FIG. 5 is a material flow diagram illustrating a second embodiment of the inventive method applied for a sintering plant, while FIG. 6 is a process flow chart of this method. To some degree, this embodiment resembles the first one and therefore will not be described again in full detail. In a first step, at 100, particulate iron ore 1 from an iron ore mine 5 and particulate charcoal 2 from a charcoal plant are provided. Particle sizes and composition can be the same as in the first embodiment.

[0053] Optionally, at 105, the particulate iron ore 1 and/or the particulate charcoal 2 may be transported by a (first) land transport 9 to the location 30 of a mixing vessel 10. At 110, the particulate iron ore 1 and the particulate charcoal 2 are mixed in the mixing vessel 10 to obtain a particle mix 8, which does not comprise a binder. Mixing may be performed actively or in a passive way, by simply pouring the particulate iron ore 1 and the particulate charcoal 2 simultaneously into the mixing vessel 10. The particle mix 8 is thus a bulk mixture of the two kinds of particulate material (iron and charcoal), that is transported in this bulk form. This embodiment distinguishes from that of FIG. 1 in that no agglomerates are formed (hence no agglomerating unit 4). The particle mix 8 may however optionally comprise some liquid, introduced with the iron ore 1. Such liquid may help to temporarily bind some charcoal fines and dust, thus reducing the inflammation risk otherwise associated with particulate charcoal 2. The particle mix 8 is thus transported in bulk particulate form (at 130) by a (first or second, respectively) land transport 11 (e.g. by railway or truck) to a first harbour 12, where they are transferred to a ship for a long-distance overseas transport 13 (at 140). It should be noted that the mixing vessel 10 may be part of a railway wagon, a truck or the like used for the land transport 11. Optionally, the land transport 11 may be unnecessary, if the mixing vessel 4 is at the first harbour 12. At a second harbour 14, the particle mix 8 is unloaded and transferred again. Subsequently, it may be transported by another land (or fluvial or other) transport 15 (at 150) to a steel plant 16 that comprises a sinter plant 20, to which the particle mix 8 is provided as raw material/feedstock. No crushing of the particle mix 8 is required and it can be used as it is. The addition of the mix material can be in the stock house (not shown) of the sintering plant or they can be added also further downstream, or even further upstream directly in the sinter mix beding pile.

[0054] Additional components 19 are added at 170 as described with respect to the first embodiment, a sinter bed is formed at 180 and sintering is performed at 190. It is again worth noting that the particle mix 8 may be fed to a stock house for mixing with the additional components 19. Alternatively, the particle mix 8 may be added directly to the sinter bed. A sinter product 21a with a defined quality is delivered at 200, which in turn can be used for steelmaking in a blast furnace, direct reduction and/or electric furnace or the like.

[0055] In the same context of the second embodiment of the inventive method, FIG. 7 illustrates a material flow diagram, where at the second location 31, the particle mix 8, is introduced into a sinter plant 20, having pellet as a product 21b, instead of sinter product 21a, while FIG. 8 is the corresponding process flow chart of this method. The two inventive methods of the second embodiment are alike, with the main difference that all components for the sintering, the additional material 19 and particle mix 8 have to be fragmented further, more specifically grinded 171. All components are then ground at a crushing unit 17, typically to a particle size of D80<0.045 mm, and pellets are formed, spheres of typically 6-16 mm diameter, before the sintering can be perform 190. After the sintering is performed 190, the pellet product 21b a defined quality is delivered at 200, which in turn can be used for steelmaking in a blast furnace, direct reduction and or furnace electric furnace or the like.

[0056] In both embodiments above, long-distance transportation is performed by ship. However, the present disclosure also covers long-distance transportation by train. In this case, the transport may be carried out in one stage, directly from the first location to the second location.