Method for supplying raw materials to a sintering plant and method of operating a sintering plant

Abstract

METHOD FOR SUPPLYING RAW MATERIAL FOR A SINTER PLANT AND METHOD OF OPERATING A SINTER PLANT. The present invention relates to a method for supplying raw material for a sinter plant (20). In order to facilitate a sintering process with reduced consumption of fossil fuels, the invention provides that a mixed material (7, 8) is used to supply raw material, wherein the mixed material (7, 8) comprises particulate iron-containing material (1) and particulate pyrolyzed biomass (2) in mixed form, wherein said iron-containing material (1) is preferably iron ore (1) and / or said pyrolyzed biomass (2) is preferably charcoal (2).

Description

1 / 24 DESCRIPTIVE REPORT “METHOD FOR SUPPLYING RAW MATERIALS TO A SINTER PLANT AND METHOD OF OPERATING A SINTER PLANT” FIELD OF THE ART

[001] The invention relates to a method for supplying raw material to a sinter plant. BACKGROUND OF THE TECHNIQUE

[002] Various iron-containing raw materials can be used to charge a blast furnace, direct reduction furnace and / or electric furnace or similar. One option is iron ore pellets, i.e., spheres typically 6-16 mm in diameter and comprising approximately 63-72% Fe, mainly in the form of Fe2O3, and various additional materials to adjust the chemical composition and metallurgical properties. Also, a bentonite-type binder is included to maintain the cohesion of the pellet. Overall, pellet production in the pelletizing plant includes grinding the ore, additives and solid fuel, i.e., anthracite coal, petroleum coke. After mixing the raw materials, the pellet is formed and thermally treated, thus called the sintering process, for example in a furnace.Pellets are a standardized, chemically stable material that can be transported without significant loss and can be used in the blast furnace without preliminary processing such as crushing or similar. Another option is sinter product, which consists of irregular porous lumps of material produced by sintering fine material (powder with 0-5 mm particle size) and disintegrating or crushing the sintered bulk material. Since the cohesion of the sinter product is achieved by the sintering process itself, it may not contain a dedicated binder. Sintering of fine iron-containing particles can only be achieved at high temperatures of around 1,000-1,300°C, sometimes even up to 1,500°C, so a sintering plant needs considerable amounts of solid fuel, which is mixed with the iron-containing material. A sinter mixture used for the sintering process can... Petition 870220094536, dated 10 / 14 / 2022, pp. 74 / 110 2 / 24 For example, it may contain fine particles of iron ore, fluxes, solid fuel, and recycled fine particles from the sintering plant itself, a blast furnace, or similar equipment. Currently, sinter is the most economical iron-containing feedstock for a blast furnace. Overall, it is more economical than pellets, as the preparation of the raw material is simpler than for pellets. However, in view of CO2 emission reduction requirements imposed on the steel industry, a disadvantage is that the sintering method leads to much higher CO2 emissions than pellet production. These are due to the solid fuel (such as coke fragments and anthracite coal) and gaseous fuel (e.g., steelmaking gases) required to withstand the high temperatures of the sintering process. PROBLEM WITH THE TECHNIQUE

[003] Thus, it is an objective of the present invention to facilitate a sintering process with reduced consumption of fossil fuels. This objective is achieved by a method according to claim 1. SUMMARY

[004] The invention provides a method for supplying raw material to a sinter plant. The raw material may also be referred to as feedstock or input material, i.e., material that is supplied / used in the sinter plant for the sintering process. The type of sinter plant is not limited within the scope of the invention. In particular, the sinter plant may be configured as a sintering plant or as a pelletizing plant. Typically, the sinter, i.e., the sinter product or pellet from the respective sinter plant, is intended to be ferrous charge material for charging a blast furnace or similar equipment.

[005] According to the inventive method, a blended material is used to supply the ferrous feedstock, wherein the blended material comprises particulate iron-containing material, generally iron ore, and particulate pyrolyzed biomass in blended form. In other words, the blended material is used to provide at least part of the material that is used for the sintering process. As Petition 870220094536, dated 10 / 14 / 2022, pp. 75 / 110 As explained below, the mixed material may, in some cases, not be used as is, but only after mechanical processing. In other cases, the mixed material may be used for the sintering process in its original form.

[006] In other words, the present invention proposes the use of a mixture of material containing particulate iron and particulate pyrolyzed biomass as a feed material (input) for a sinter plant (in particular, a sintering plant or pelletizing plant). The expression 'mixture of material containing particulate iron and particulate pyrolyzed biomass' means that the two types of particulates are not transported and fed individually into the sinter plant, but are mixed. The mixing can occur hundreds or thousands of kilometers away from the place of use, i.e., the sinter plant, and transporting the iron particles and biomass as a mixture provides numerous advantages detailed below. In general, the mixture of material containing particulate iron and particulate pyrolyzed biomass can be a bulk mixture, i.e., the particulates are simply combined / mixed in a container, possibly with some mechanical agitation.The term mixture, however, also covers the case where the mixture of material containing particulate iron and particulate pyrolyzed biomass is processed to form agglomerates. In the first case, the feed material supplied to the sinter plant is a bulk / powdered material of particulate iron-containing material and particulate pyrolyzed biomass. In the latter case, the feed material supplied to the sinter plant takes the form of agglomerates (or lumpy products) comprising particulate iron-containing material and particulate pyrolyzed biomass.

[007] The type of sinter plant is not limited within the scope of the invention. The term 'sinter plant' is used here to cover a machine or plant that involves the sintering (or frying) of material, that is, the formation of a solid mass of particulate material by heat without melting it to the point of liquefaction. Sintering plants and pelletizing plants, as known in the industry of Petition 870220094536, dated 10 / 14 / 2022, pp. 76 / 110 4 / 24 iron production, there are two types of sintering plants that involve a 'sintering process'.

[008] According to the present method, the mixed material comprises pyrolyzed biomass, wherein the latter is generally charcoal. Typical pyrolysis temperatures are between 250 and 550°C, whereby the term 'pyrolysis' herein also covers mild pyrolysis known as torrefaction. The biomass, however, may also be any plant or animal material. For simplicity, this document will hereafter generally refer to charcoal only. It is understood that throughout this document, the term “charcoal” may be replaced by “pyrolyzed biomass”. Similarly, the term “iron ore” may hereafter be replaced by “iron-containing material”.

[009] Iron ore and charcoal are present in the mixed material in particulate form, i.e., as particles or chunks. The particle size is generally not limited within the scope of the invention, although certain particle sizes are preferred, as will be discussed below. The iron ore referred to in this application may generally comprise any iron-containing material, for example, iron oxides such as magnetite (Fe3O4) or hematite (Fe2O3), usually together with mineral gangue and also loss or residual materials. Charcoal may be any carbon-containing material produced by the removal of water and volatile constituents from biomass, typically from plant materials such as wood, organic residue and / or residual biomass, and / or SRF material (solid recovery fuels).Charcoal particles can have a relatively high carbon content, for example, above 65% by weight, above 70% by weight, or above 75% by weight.

[010] To obtain the blended material, at least particulate iron ore and particulate charcoal are provided and can then be mixed to obtain the blended material. The mixing can be carried out in various ways, such as actively by mechanically mixing the iron ore and charcoal particles (plus other optional components) in a suitable container. Petition 870220094536, dated 10 / 14 / 2022, pp. 77 / 110 5 / 24 Suitable devices include a pin mixer, a paddle mixer, or a rotary drum mixer. Mixing can also be carried out more or less passively, for example, by pouring iron ore particles and charcoal particles into a container simultaneously, which will also result in at least some degree of mixing. Other suitable mixing methods known in the technology can also be used. Optionally, mixing can be combined with loading onto a transport container, such as a truck, container, train wagon, ship, or similar. This can be a form of passive mixing, as indicated above, or it can be combined with active mixing immediately before or after loading the particulate material into the transport container.

[011] In embodiments, the volumetric proportion of particulate iron-bearing material in the mixed material can be between 5 and 80% by vol.

[012] The inventive method has several advantages. First, charcoal can be considered CO2 neutral, since it is (usually) generated without the use of fossil fuels. Since at least part of the fuel needed for the sintering process is provided by the charcoal contained in the blended material, the actual CO2 emissions can be significantly reduced. Other advantages relate to the handling and transport of the blended material containing charcoal. Since charcoal production requires large quantities of biomass, it is almost impossible to have a charcoal production facility and a sinter plant in the same geographical location. Therefore, the charcoal needs to be transported. In this context, using blended material containing iron ore particles and charcoal particles reduces the necessary safety precautions compared to charcoal as such.Charcoal is a flammable product that typically requires high safety procedures and precautions. Depending in part on the percentage of charcoal contained in the mixed material, flammability can be significantly reduced. Of course, this also depends on other factors. Petition 870220094536, dated 10 / 14 / 2022, pp. 78 / 110 6 / 24 optional components of the mixed material. Furthermore, pure charcoal has a very low density (about 0.25 g / cm3) and usually contains a high percentage of fine particles, which makes its handling complicated due to dust emissions at discharge points. After the charcoal particles have been mixed with iron ore particles and, optionally, other components, the quantities of fine particles, as well as dust emissions, can be reduced. This is due to different factors, such as, for example, the higher density of the iron ore particles protecting the embedded charcoal particles from being extirpated and the iron ore particles being wetted, so that, in the mixed material, fine charcoal particles can be at least partially bound by the liquid contained in the iron ore particles.

[013] As a mixed material, charcoal is thus available for long-distance transport. Such long distance may be defined as comprising a distance of at least 100 km, preferably at least 500 km, most preferably even several thousand kilometers. Charcoal may thus, for example, be transported from Brazil or Canada to the United States of America or from Brazil, Canada, the United States, Indonesia or Russia to Europe. Long-distance transport is preferably carried out by rail or ship.

[014] According to one embodiment, the mixed material is used in the form of composite bodies, wherein each composite body is solid and coherent and comprises particulate iron ore and particulate charcoal. Each of the composite bodies is solid and coherent, that is, the individual particles are linked to form the composite body, while the method of linking these particles is not limited in this context. In particular, each composite body can be considered as an agglomerate or conglomerate comprising these particles. The iron ore particles and the charcoal particles are linked as parts of the composite body. To a certain extent, the composite body is not Petition 870220094536, dated 10 / 14 / 2022, pp. 79 / 110 7 / 24 homogeneous, but it is a combination of at least particulate iron ore and particulate charcoal. When charcoal particles are bound as part of the composite bodies, the amounts of fine particles, as well as dust emissions, are significantly reduced. Even if fine particles cannot be completely eliminated, their percentage is usually below 10%, or even below 5%, with the rest being intact composite bodies. As will be explained below, composite bodies may, in some cases, not be used as is, but only after mechanical processing. In this case, the raw material is only in the form of composite bodies during a certain stage of the supply process, although it may be in another form immediately before being used in the sinter plant. In other cases, composite bodies may be used for the sintering process in their original form.

[015] The method may also include the production of composite bodies. In this case, the process includes the following steps before the supply of raw materials. Firstly, particulate iron ore and particulate charcoal are provided. Typically, iron ore, as well as charcoal, need to be broken, crushed, or fragmented and possibly ground to obtain particulate form. Also, the particles may be sieved to obtain a certain particle size range. Crushing and / or sieving may be part of the provision of the respective particulate material.

[016] In another step, at least the iron ore and charcoal are mixed to obtain a mixture. Mixing can be carried out in several ways, such as actively by mechanically mixing the iron ore and charcoal particles (plus other optional components) in a suitable container. Suitable devices include a pin mixer, a paddle mixer, or a rotary drum mixer. Mixing can also be carried out more or less passively, for example, by pouring the iron ore particles and charcoal particles into a container at the same time, which will also result in at least some degree of mixing. Other methods Petition 870220094536, dated 10 / 14 / 2022, pp. 80 / 110 Suitable 8 / 24 mixtures known in the technology can also be used.

[017] In a further step, the composite bodies are formed from the mixture. Each of the composite bodies can be considered as an agglomeration or conglomerate containing both iron ore particles and charcoal particles. Depending on the size of the composite bodies, they can be referred to, for example, as blocks, briquettes or pellets, or also simple agglomerates in the form of filter cakes or similar. All composite bodies can have the same size and shape or have various sizes and / or shapes. This depends partly on the method of forming the composite bodies. The shape of a single composite body can be irregular or regular, for example spherical, cylindrical or cuboid. Mixing and formation can be carried out by a single device. The composition of the mixture can be identical to the composition of the mixed material, i.e., of the composite bodies.However, their composition may differ, for example, due to liquid components that evaporate during the formation of the composite bodies. Therefore, the terms "mixture" and "mixed material" are not used synonymously in this context.

[018] In some embodiments, sufficient cohesion of the composite bodies can be achieved, for example, by applying high pressure and / or temperature to the mixture of iron ore and charcoal. In other cases, the degree of cohesion achievable by this approach is not sufficient. Therefore, the method may further comprise providing at least one binder, and the mixture is obtained by mixing at least iron ore, charcoal, and at least one binder. Even if production is not considered part of the method, each composite body contains at least one binder. The respective binder serves to increase the overall cohesion of the individual composite body. As the mixture is formed, the binder may be present in liquid form and / or resolved or suspended in a liquid. Once composite bodies have been formed, liquid components may be evaporated or chemically converted by applying heat to the composite bodies.In some cases, it may be acceptable if... Petition 870220094536, dated 10 / 14 / 2022, pp. 81 / 110 9 / 24 a certain amount of the liquid introduced by the binder is present in the compound body.

[019] According to an embodiment, at least one organic binder is provided. Examples of suitable organic binders include, but are not limited to, various types of cellulose, dairy residue (such as lactose or whey), natural gum (such as guar or xanthan gum), wood-related products (such as hemicellulose or lignin sulfonate), starches, dextrose, molasses (such as sugarcane molasses), and those based on polyacrylamide or polyacrylate structures. Most organic binders can be burned during the sintering process with little or no solid residue. Also, since they originate mostly from biomass, they can be considered CO2 neutral.

[020] Alternatively or additionally, at least one mineral binder may be provided. Examples of mineral binders include, but are not limited to, bentonite, lime, quicklime (CaO), slaked lime (Ca(OH)2). In general, mineral binders (i.e., inorganic binders) do not burn during the sintering process but remain, possibly in a chemically altered form, as part of the sinter or pellet product. Depending on the intended use in the blast furnace, direct reduction furnace and / or electric furnace or similar, these binder residues may be irrelevant, harmful or even beneficial. In some cases, mineral binders may be more effective than organic binders.

[021] Preferably, the composite bodies are formed by briquetting. In this context, "briquetting" refers to agglomeration by pressure. A certain quantity of the mixture is subjected to pressure, whereby the agglomeration of the particles (and possibly other components) is caused or supported. Several types of briquetting can be carried out, for example, extrusion or roller pressing. If extrusion is carried out, the primary product is a continuous strip of material that needs to be cut or otherwise separated into composite bodies. In addition to the application of pressure, a high temperature may be applied, or by Petition 870220094536, dated 10 / 14 / 2022, pp. 82 / 110 10 / 24 Heating of the mixture or certain parts of the briquetting machine that come into contact with the mixture. Alternatively or additionally, heat may be generated by friction or compression. In the manner described above, the composite bodies resulting from the briquetting process may be referred to as bricks, blocks, briquettes, or pellets.

[022] In embodiments, the mixed material is not subjected to agglomeration to form composite bodies, but is used as a bulk mixture of particulate iron ore and particulate charcoal and therefore transported and supplied to the sinter plant in this form. In this case, too, the previously disclosed steps of crushing / crushing / fragmentation / grinding and / or mixing (passive or active) may apply.

[023] As mentioned above, the charcoal production site and the sinter plant site are usually separate. They may be in different countries or even on different continents. Since charcoal can be transported much more easily and safely than when it is combined with iron ore particles in the mixed material, especially when it is bound in the form of composite bodies together with the iron ore particles, the mixed material (possibly in the form of composite bodies) should be formed at or near the charcoal plant. This largely avoids any risk of ignition or dust generation problems associated with the transport of charcoal.According to a typical embodiment of the invention, the mixed material (and, in particular, the composite bodies) is formed at a first location, and the method further comprises transporting the mixed material to a second location, which is at least 100 km from the first location. The second location could be the sinter plant site. The distance between the first and second locations could be even greater, for example, at least 500 km or several thousand kilometers. In particular, the mixed material could be transported at least partially by train or ship. Under these conditions, the cost-effectiveness of the transport largely depends on the total mass transported. Since... Petition 870220094536, dated 10 / 14 / 2022, pp. 83 / 110 11 / 24 Charcoal and iron ore (plus optional additional components) are transported together, significantly increasing the total mass to be transported for a given quantity of charcoal. In other words, a cost-effective transport (of, for example, 200,000 t) can be carried out with a smaller quantity of charcoal. For example, if a sintering plant has a production rate of 6 million TPA and requires 60 kg of charcoal for 1 t of sinter product, a total quantity of 360,000 TPA of charcoal is needed. If the mixed material contains 30% charcoal, a cost-effective transport can be carried out every two months. Such a relatively high transport frequency is beneficial as it reduces the storage capacity required at both the first and second locations.In order to reduce the flammability of charcoal, it will be mixed with iron-bearing material that is not flammable by itself. The proposed volumetric ratio of iron-bearing material in the mixture corresponds approximately to the void volume of the charcoal (volume between the charcoal particles), which will normally be between approximately 30 and 55% by volume. Higher volumetric ratios of iron ore, even above 55% by volume, may be preferred to further reduce flammability. Those skilled in the art can determine the minimum quantity depending on the characteristics of the iron-bearing material and the charcoal, on a case-by-case basis, in consideration of specific flammability and explosion tests.

[024] Despite the aforementioned advantages of a charcoal content that is not too high, the charcoal content should also not be too low, since it is desirable that charcoal and iron ore be present in a ratio that is more or less appropriate for the sintering process, considering, however, that production may use various sources of ore and / or sources of charcoal. It is therefore desirable that the mixed material comprise at least 1% by weight or 10% by weight of charcoal, preferably at least 20% by weight, more preferably at least 30% by weight. Petition 870220094536, dated 10 / 14 / 2022, pp. 84 / 110 12 / 24 by weight. Particularly preferred ranges are 1 to 30% by weight, 5 to 20% by weight, and possibly 10 to 20% by weight. If the mixed material is in the form of composite bodies, the percentage by weight in the mixture from which they are formed may be somewhat lower, for example, because the mixture contains liquid components that are evaporated in the method of forming the composite bodies.

[025] In order to benefit from the aforementioned advantages connected with a reduction in charcoal content and in order to provide a sufficient quantity of iron ore for the sintering process, it is advantageous if the mixed material comprises at least 20% by weight of iron ore, preferably at least 30% by weight, more preferably at least 50% by weight. Again, if this refers to composite bodies, the percentage by weight in the mixture from which these composite bodies are formed may be somewhat lower, for example, due to the evaporation of the liquid components.

[026] The formation of coherent composite bodies, which can usually be considered as agglomerates or conglomerates, is usually easier if the charcoal particles are relatively small. Also, a smaller individual charcoal particle size can enhance the effectiveness of the charcoal in the sintering process plant, regardless of whether the mixed material is in the form of composite bodies or not. It is therefore preferred that the particulate charcoal have a D90 sieve size below 10 mm, preferably below 5 mm, more preferably below 3.5 mm. In other words, at least 90% of the charcoal particles have a maximum dimension below 10 mm (or 5 mm or 3.5 mm, respectively).

[027] Various types of iron-containing material, generally iron ore, can be used for the blended material (e.g., in composite bodies or agglomerates) in the inventive method. According to one embodiment, the particulate iron-containing material comprises sinter feed particles, which have a sieve size at least predominantly between 0.1 mm and 6.3 mm. “Sinter feed” is a term that is commonly used for a raw material. Petition 870220094536, dated 10 / 14 / 2022, pp. 85 / 110 13 / 24 containing iron with the aforementioned relatively large / coarse grain size. It is generally produced from iron ores whose chemical properties make it suitable for blast furnace, direct reduction furnace and / or electric reduction furnace or similar operation without further refinement. In other words, the iron content in the iron ore is relatively high from the start, i.e., the gangue material content is low, since the iron compound(s) and gangue material are relatively well separated. If reference is made to a sieve size of “at least mostly” between 0.1 mm and 6.3 mm, this may refer to at least 80% or at least 90% of the particles having a maximum dimension between 0.1 mm and 6.3 mm.

[028] Alternatively, in the case of the pelletizing plant or, additionally, in the case of the sintering plant, the particulate iron ore may comprise iron-containing material with a smaller grain size, such as concentrate and / or pellet feed particles (hereinafter simply referred to as “pellet feed”), which have a sieve size at least predominantly below 0.15 mm. Again, this may refer to at least 80% or at least 90% of the particles having a maximum dimension below 0.15 mm. “Pellet feed” is a fine iron ore material resulting from the refinement of low-grade iron ores. In such low-grade iron ores, the iron content is low and the iron compounds and gangue material are not well separated.However, if the iron ore is ground or otherwise separated so that the particle size is reduced, it becomes possible to separate particles with a sufficiently high iron content from those with a lower (or non-existent) iron content. The particles with the high iron content can then be used as pellet feed. As a general trend for sintering plants, the quality of sinter feed is deteriorating, as suitable iron ores are no longer readily available. This can be compensated for by at least partially including pellet feed. Petition 870220094536, dated 10 / 14 / 2022, pp. 86 / 110 14 / 24

[029] As described above, the dimensions of the composite bodies are, in general, not limited within the scope of the invention. Preferably, however, the composite bodies have a maximum dimension between 1 mm and 500 mm. If the maximum dimension is below or above this range, the production and / or handling of the composite bodies becomes difficult. Small composite bodies, for example, with a maximum dimension below 15 mm, can be referred to as “pellets”, while larger composite bodies, for example, with a maximum dimension between 15 mm and 100 mm, can be referred to as “briquettes”, and even larger composite bodies can be referred to as “blocks” or “bricks”. As described above, the individual composite body can be spherical, cylindrical, cuboid, flat, or even irregularly shaped.

[030] Especially if the maximum dimension of the individual composite body is small, it is conceivable that the composite bodies are used in the sinter plant as is, i.e., without further processing. According to another embodiment, the composite bodies are fragmented before being used in the sinter plant. Fragmentation can, in particular, be carried out by crushing the composite bodies. The fragmentation process can lead to a partial or complete separation of the charcoal particles from the iron ore particles and possibly also to a fragmentation of individual charcoal and / or iron ore particles. Especially during the use of the material in a pelletizing plant, the material is usually ground before entering the sintering process.

[031] In the sintering plant, there are mainly two methods of adding the charcoal / iron ore mixture to the sintering process. The charcoal / iron ore mixture can be added to a sinter mix bed pile. The sinter mix bed pile typically consists of horizontal layers of different raw materials. When a sinter mix bed pile is used, reclaimers typically remove the material in a vertical manner perpendicular to the layers. This allows for good mixing of the material, also, during Petition 870220094536, dated 10 / 14 / 2022, pp. 87 / 110 15 / 24 longer time periods (e.g., one to several weeks). In this case, it is easily possible to add the charcoal / iron ore mixture directly. Precautions regarding its segregation into charcoal and iron ore particles during stacking are thus limited. However, depending on the stacking process and whether dosing containers are included, the segregation effect described below also needs to be considered. The second possibility of introducing the carbonized charcoal / iron ore mixture into the sintering plant is in the sintering plant's storage building. In this case, the mixture will be dosed into the sintering process by special dosing systems, such as loss-in-weight feeders, weighing conveyors, screw feeders, or others.In this case, it is important that the charcoal / iron ore mixture is not segregated, as segregation will lead to uncontrolled composition of the sinter mixture, resulting in problems during the sintering process.

[032] In the case of a pelletizing plant using a charcoal / iron ore mixture, the second possibility does not apply, since the material needs to be ground before entering the sintering process. Therefore, the segregation effects, as described above, are not relevant.

[033] The fragmentation of compounds is therefore preferably carried out shortly before the fragmented material is introduced into the sintering process of a sintering plant, thereby avoiding or minimizing any problems associated with dust generation or charcoal ignition. Preferably, the crushing of the compounds can be carried out at the outlet of the storage silo, just upstream of the dosing device. Although this is not usual, it is also conceivable that the mixed material is fragmented even if it is not in the form of compound bodies. On the other hand, in the fragmentation of compounds when introduced into the pelletizing plant, all components must be ground, separately or together in a grinding unit, before the sintering process. Petition 870220094536, dated 10 / 14 / 2022, pp. 88 / 110 16 / 24

[034] It is desirable that the blended material can be used in the sintering method with no or only a minimum of additional material. That is, the blended material can represent the majority of the feedstock in the sintering process. However, in practice, the blended material can provide at least 10% by weight of the iron-containing material and at least 5%, preferably at least 10%, and more preferably at least 20% by weight of the carbon-containing material (fixed carbon) for a sintering process in the sintering and pelletizing plant. In particular, in the case of the sintering plant, it is preferred that only a small amount of pellet feed needs to be added to the feedstock, for example, corresponding to 90% by weight or less of the iron-containing material, possibly less than 60% by weight.The blended material may provide at least 10%, preferably at least 40% by weight, or more preferably at least 60% by weight of the carbon-containing material. It is also preferred that neither anthracite and / or coke fragments need to be added to the feedstock nor that the amount of this additional fuel corresponds to 80% by weight or less of the carbon-containing material, for example, less than 60% by weight or less than 40% by weight.

[035] In this document, the word sintering means an agglomeration of ores formed by heat treatment, the so-called sintering process. The resulting product may, for example, be a pellet or sinter.

[036] As indicated before, the term sinter plant, in this document, covers an ore agglomeration plant, in general, involving a sintering process, in particular, a pelletizing plant and a sintering plant.

[037] This can typically be achieved by subjecting the mixture to heat treatment in a furnace to support the sintering process, typically at 1,000 to 1,400°C, and typically under an oxidizing atmosphere (O2 still contained in the gas atmosphere in considerable quantity), similar to conventional pelletizing and sintering processes. BRIEF DESCRIPTION OF THE DRAWINGS Petition 870220094536, dated 10 / 14 / 2022, pp. 89 / 110 17 / 24

[038] Preferred embodiments of the invention will now be described, by way of example, in relation to the accompanying drawings, in which: Figure 1 is a material flowchart illustration of a method according to a first embodiment of the present invention related to a sintering plant; Figure 2 is a process flowchart of the method in Figure 1; Figure 3 is a material flowchart illustration of a method according to a first embodiment of the present invention related to a pelletizing plant; Figure 4 is a process flowchart of the method in Figure 3; Figure 5 is a material flowchart illustration of a method according to a second embodiment of the present invention related to a sintering plant; and Figure 6 is a process flowchart of the method in Figure 5; Figure 7 is a material flowchart illustration of a method according to a second embodiment of the present invention related to a pelletizing plant; and Figure 8 is a process flowchart of the method in Figure 7. DESCRIPTION OF PREFERRED MODALITIES

[039] Figure 1 is a material flowchart illustrating a first embodiment of the inventive method applied to a sintering plant, while Figure 2 is a process flowchart of this method. The method will now be explained in relation to both figures. In a first step of the method, in 100, iron ore in particulate iron-containing material 1, charcoal in particulate pyrolyzed biomass 2 and a binder 3 are provided. For simplicity, the present description will use iron ore 1 as iron-containing material 1 and charcoal 2 as pyrolyzed biomass 2. This, however, should not be understood as limiting.

[040] Particulate iron ore 1 is provided from a material source Petition 870220094536, dated 10 / 14 / 2022, pp. 90 / 110 18 / 24 containing iron, such as, for example, an ore mine 5, while the particulate charcoal is supplied from a charcoal plant 6. In this embodiment, the particulate iron ore 1 comprises sinter feed, with a particle size between 1 and 6.3 mm, as well as pellet feed, with 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 the slow pyrolysis of the plant material, for example, wood, may have a D90 sieve size below 3.5 mm. The charcoal particles may have a relatively high carbon content, for example, above 65% by weight, above 70% by weight or even above 75% by weight. Binder 3 can be a mineral binder, such as bentonite, or an organic binder, such as sugarcane molasses.It can also be a combination of a mineral binder and an organic binder.

[041] In a subsequent step, at 110, particulate iron ore 1, particulate charcoal 2, and 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 may be added to facilitate the mixing process. From this mixture, agglomerates 7 are formed (at 120) in an agglomeration unit 4, where mixing may also be carried out. The agglomeration unit 4 may be located near 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 agglomeration unit 4 near the iron ore mine or the shipping port. Optionally, the formed agglomerates 7 may be subjected to a high temperature to cure the binder 3 or to evaporate the liquid components.The resulting agglomerates 7 comprise particulate iron ore 1, particulate charcoal 2, and binder 3, which may possibly be chemically altered from their initial form by a curing process or similar means. The agglomerates 7 may be, for example, cuboids with a maximum dimension of... Petition 870220094536, dated 10 / 14 / 2022, pp. 91 / 110 19 / 24 cm.

[042] The agglomerates 7 in their finished state represent coherent solid composite bodies that are well suited for storage and transport. In particular, since charcoal 2 is bound in the agglomerates, they require special safety precautions and the risk of ignition associated with pure charcoal 2 is largely eliminated. The finished agglomerates 7 are transported (in 130) by a first land transport 11 (e.g., by rail or truck) to a first port 12, where they are transferred to a ship for long-distance overseas transport 13 (in 140). Optionally, the first land transport 11 may be unnecessary if the briquetting unit is close to the first port 12. After the ship has reached its destination, a second port 14, the agglomerates 7 are unloaded and transferred again.Subsequently, the same can be transported by another land transport 15 (in 150) to a steel mill 16 comprising a crushing unit 17 and a sinter plant 20. As a preparation for use in the sinter plant 20, the agglomerates 7 are crushed (in 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, for example, 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 may comprise at least one charcoal particle bound together with an iron ore particle.There may be a dedicated container (not shown) in the storage house of the sinter plant 20 where the agglomerates 7 are stored. These can then be dosed, crushed, and placed in the transport system (e.g., conveyor belt) that feeds the mixing drum or similar equipment of the sinter plant 20. Alternatively to adding the mixing material in the storage house of the sinter plant, they can also be added. Petition 870220094536, dated 10 / 14 / 2022, pp. 92-110 20 / 24 additionally downstream or upstream directly in the sinter mixture bed pile.

[043] The crushing unit 17 may be located relatively close to the sinter plant 20 and special precautions may 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 risk of ignition associated with charcoal particles. Additional components 19 are added in 170, which may comprise, for example, pellet feed and / or sinter feed to supplement the iron ore of the agglomerates 7, fossil fuel such as anthracite and / or coke fragments, non-fossil fuel or a combination of both to complete the energy requirement for the sintering process, lime, water or other suitable additives. So, a sinter bed is formed at 180 and sintering is carried out at 190. It is worth noting that the crushed material 18 can be fed into a storage house for mixing with the additional components 19.Alternatively, the crushed material 18 can be added directly to the sinter bed. The charcoal from the agglomerates 7 can represent all the fixed carbon-containing material for the sintering process. Normally, however, this represents only a part, for example between 20% and 90% by weight, of the carbon-containing material. In both ways, the amount of fossil fuel is enormously reduced, if not eliminated, so the sintering process is close to CO2 neutral. As a result of the sintering process, a sinter product 21a with a defined quality is distributed in 200, which, in turn, can be used for steelmaking in a blast furnace, direct reduction furnace and / or electric furnace or similar.In the same context as the first embodiment of the inventive method, Figure 3 illustrates a material flow diagram, in which, at the second location 31, the mixture of compounds 7 is introduced into a sinter plant 20, with the pellet as a product 21b, instead of the sinter product 21a, while Figure 4 is the corresponding process flow diagram of this method. The two inventive methods of the first embodiment are similar, with the main difference being that... Petition 870220094536, dated 10 / 14 / 2022, pp. 93 / 110 21 / 24 All components for sintering, the additional material 19 and the crushed material 18 or the agglomerated composite body 7 need to be further fragmented, more specifically ground 171. All components are then ground in a grinding unit 17, typically to a particle size of D80 < 0.045 mm, and pellets are formed 180, spheres typically 6 - 16 mm in diameter, before sintering can be carried out 190. After sintering is carried out 190, the pellet product 21b of a defined quality is distributed in 200, which, in turn, can be used for steelmaking in a blast furnace, direct reduction furnace and / or electric furnace or similar.

[044] Figure 5 is a material flow diagram illustrating a second embodiment of the inventive method applied to a sintering plant, while Figure 6 is a process flow diagram of this method. To some extent, this embodiment resembles the first 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. The particle sizes and composition can be the same as in the first embodiment.

[045] Optionally, in 105, particulate iron ore 1 and / or particulate charcoal 2 may be transported by a (first) land transport 9 to the location 30 of a mixing vessel 10. In 110, particulate iron ore 1 and particulate charcoal 2 are mixed in the mixing vessel 10 to obtain a particle mixture 8, which does not comprise a binder. The mixing may be carried out actively or in a passive manner, simply by the flow of particulate iron ore 1 and particulate charcoal 2 simultaneously inside the mixing vessel 10. The particle mixture 8 is thus a bulk mixture of the two types of particulate material (iron and charcoal), which is transported in this bulk form. This embodiment differs from that of figure 1 in that no agglomerate is formed (therefore, no agglomeration unit 4). The particle mixture 8 may, however, optionally comprise some Petition 870220094536, dated 10 / 14 / 2022, pp. 94 / 110 22 / 24 liquid, introduced with the iron ore 1. This liquid can help to temporarily bind some fine particles of charcoal and dust, thus reducing the risk of ignition otherwise associated with particulate charcoal 2. The particle mixture 8 is thus transported in bulk particulate form (in 130) by a (first or second, respectively) land transport 11 (e.g., by rail or truck) to a first port 12, where it is transferred to a ship for long-distance overseas transport 13 (in 140). It should be noted that the mixing container 10 may be part of a railway wagon, a truck or similar used for land transport 11. Optionally, land transport 11 may be unnecessary if the mixing container 4 is at the first port 12. At a second port 14, the particle mixture 8 is unloaded and transferred again.Subsequently, it can be transported by another land (or river or other) transport 15 (in 150) to a steel plant 16 comprising a sinter plant 20, in which the particle mixture 8 is provided as raw material / input. No grinding of the particle mixture 8 is required, and it can be used as is. The addition of the mixture material can be in the storage house (not shown) of the sinter plant or it can also be added downstream, or even upstream, directly to the sinter mixture bed pile.

[046] Additional components 19 are added at 170, in the manner described in relation to the first embodiment, a sinter bed is formed at 180 and sintering is carried out at 190. It is again worth noting that the particle mixture 8 can be fed into a storage house for mixing with the additional components 19. Alternatively, the particle mixture 8 can be added directly to the sinter bed. A sinter product 21a with a defined quality is distributed at 200, which, in turn, can be used for steelmaking in a blast furnace, direct reduction and / or electric furnace or similar.

[047] In the same context as the second modality of the inventive method, the figure Petition 870220094536, dated 10 / 14 / 2022, pp. 95 / 110 Figure 23 / 24 illustrates a material flow diagram, in which, at the second location 31, the particle mixture 8 is introduced into a sinter plant 20, having pellet as a product 21b, instead of the sinter product 21a, while Figure 8 is the corresponding process flow diagram of this method. The two inventive methods of the second embodiment are similar, with the main difference being that all components for sintering, the additional material 19 and the particle mixture 8 need to be further fragmented, more specifically ground 171. All components are then ground in a grinding unit 17, typically to a particle size of D80 < 0.045 mm, and pellets are formed, spheres typically 6-16 mm in diameter, before sintering can be carried out 190.After sintering is carried out 190, the pellet product 21 b of a defined quality is distributed in 200, which, in turn, can be used for steelmaking in a blast furnace, direct reduction furnace and / or electric furnace or similar.

[048] In both of the described modes, long-distance transport is carried out by ship. However, the present invention also covers long-distance transport by rail. In this case, the transport can be carried out in one stage, directly from the first location to the second location. LEGEND FOR REFERENCE NUMBERS iron-containing material, iron ore pyrolyzed biomass, charcoal binder agglomeration unit iron ore mine charcoal plant composite body, agglomerate particle mixture land transport mixing container land transport Petition 870220094536, dated 10 / 14 / 2022, pp. 96 / 110 24 / 24 land transport port long-distance overseas transport port means of transport steel mill crushing or grinding unit crushed or ground material additional material sinter plant (sintering plant or pelletizing plant) 21a sinter product 21b pellet product first location second location Petition 870220094536, dated 10 / 14 / 2022, pp. 97 / 110

Claims

1 / 4 CLAIMS 1. Method for supplying raw material to a sinter plant (20), wherein a mixed material (7, 8) is used to supply raw material, wherein the mixed material (7, 8) comprises particulate iron-containing material (1) and particulate pyrolyzed biomass (2) in mixed form, characterized in that said mixed material (7, 8) is transported over a long distance, said long distance being at least 100 km, and wherein the mixed material (7, 8) comprises at least 20% by weight of iron-containing material (1).

2. Method according to claim 1, characterized in that said long distance is at least 500 km, preferably several thousand kilometers, and / or said mixed material (7, 8) is transported over a long distance by train or ship.

3. Method according to any one of claims 1 to 2, characterized in that the mixed material (7, 8) is used in the form of composite bodies (7), wherein each composite body (7) is solid and coherent and comprises material containing particulate iron (1) and pyrolyzed biomass (2); and preferably in that the composite bodies (7) have a maximum dimension between 1 mm and 500 mm; and preferably the composite bodies (7) are fragmented (160) before being used in the sinter plant (20).

4. Method according to claim 3, characterized in that it comprises, before the supply of raw material: - providing (100) material containing particulate iron (1) and particulate pyrolyzed biomass (2); - mixing (110) at least the iron-containing material (1) and the pyrolyzed biomass (2) to obtain a mixture; and - forming (120) the composite bodies (7) from the mixture; and preferably wherein the method further comprises providing (100) at least one binder (3) and the mixture is obtained by mixing (110) at least the iron-containing material (1), the pyrolyzed biomass (2) and at least one binder (3), wherein said at least one binder comprises an organic binder and a mineral binder.

5. Method according to any one of claims 3 to 4, characterized in that the agglomerates are formed by briquetting.

6. Method according to any of the preceding claims, characterized in that the mixed material (7, 8) is supplied in bulk form to the sinter plant (20).

7. Method according to any of the preceding claims, characterized in that the mixed material (7, 8) comprises at least 1% by weight of pyrolyzed biomass (2), preferably at least 5% by weight, more preferably at least 10% by weight.

8. Method according to any of the preceding claims, characterized in that the mixed material (7, 8) comprises at least 30% by weight of iron-containing material (1), preferably at least 50% by weight; and / or in that the volumetric proportion of particulate iron-containing material in the mixed material (7, 8) is between 5 and 80% by volume.

9. Method according to any of the preceding claims, characterized in that the particulate pyrolyzed biomass (2) has a D90 sieve size below 10 mm, preferably below 5 mm, more preferably below 3.5 mm.

10. Method according to any of the preceding claims, characterized in that the particulate iron-containing material (1) comprises sinter feed particles having a sieve size at least predominantly between 0.1 mm and 6.3 mm; and / or in that the particulate iron-containing material (1) comprises pellet feed particles having a sieve size predominantly at least below 0.15 mm.

11. Method according to any of the preceding claims, characterized in that the mixed material (7, 8) provides at least 10% by weight of the iron-containing material and at least 5% by weight of the carbon-containing material for Petition 870260031806, dated 06 / 04 / 2026, page 23 / 25 3 / 4 a sintering process (190) in the sinter plant (18).

12. Method according to any of the preceding claims, characterized in that said iron-containing material (1) is iron ore (1) and / or said pyrolyzed biomass (2) is charcoal (2) and / or said composite body (7) is an agglomerate (7) or a conglomerate.

13. Method of operating a sinter plant (20), wherein iron-containing material (1) and carbon-containing material are supplied to said sinter plant (20), and the same are heated in a furnace to undergo a sintering process in order to form solid iron-containing products, characterized in that the sinter plant (20) is supplied with mixed material (7, 8) according to a method as defined in any of the preceding claims.

14. Method according to claim 13, characterized in that the mixed material (8) is a bulk mixture of particulate iron-containing material (1) and particulate pyrolyzed biomass; or in that the mixed material (7) comprises agglomerates of particulate iron-containing material (1) and particulate pyrolyzed biomass.

15. Method according to any one of claims 13 to 14, characterized in that the sinter plant (20) is configured as a sintering plant, the mixed material (7, 8) being optionally crushed and / or combined with additional components, and optionally agglomerated, before being fired in a furnace under an oxidizing atmosphere, and grinding of the resulting sinter product; or in that the sinter plant is configured as a pelletizing plant, the method comprising the steps of, in the sinter plant (20), grinding the mixed material (7, 8) and forming, from the same, green iron ore pellets, and loading and firing said green pellets in a hardening furnace under an oxidizing atmosphere to form hardened pellets; wherein preferably the mixed material (7, 8) and the additional material including binder material are ground in a grinding unit (17) of the pelletizing plant, preferably Petition 870260031806, dated 06 / 04 / 2026, page.24 / 25 4 / 4 down to a particle size of D80 < 0.045 mm, and green pellets are formed from the ground materials, preferably in spheres of about 6 to 16 mm in diameter. Petition 870260031806, dated 06 / 04 / 2026, page 25 / 25.

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