Method for supplying raw materials to a sintering plant

Abstract

The present invention relates to a method for supplying raw materials to a sintering plant (20), the method comprising the step of supplying raw materials using a mixed material (7, 8) to facilitate the sintering process with reduced consumption of fossil fuels, the mixed material (7, 8) comprising a granular iron-bearing material (1) and a granular pyrolyzed biomass (2) in a mixed form, the iron-bearing material (1) being preferably iron ore (1) and the pyrolyzed biomass (2) being preferably charcoal (2).

Description

Technical Field

[0001] The present invention relates to a method for supplying raw materials to a sintering plant.

Background Art

[0002] Various iron-containing raw materials can be used for charging into blast furnaces, direct reduction and / or electric furnaces, etc. One option is iron ore pellets, i.e., typically spheres with a diameter of 6 - 16 mm, mainly in the form of Fe2O3, containing about 63 - 72% Fe and various additional materials for adjusting the chemical composition and metallurgical properties. Binders such as bentonite are also included to maintain the cohesion of the pellets. Generally, the production of pellets in a pelletizing plant includes grinding ores, additives, and solid fuels, i.e., anthracite and petroleum coke. After mixing the raw materials, pellets are formed and heat treatment, i.e., a so-called sintering process in a kiln for example, is carried out. Pellets are standardized materials that can be transported without significant loss chemically and can be used in blast furnaces without pretreatment such as crushing. Another option is sintered products, which consist of lumps of irregular and porous materials produced by sintering fine powder materials (powders with a particle size of 0 - 5 mm) and disintegrating or crushing the sintered bulk materials. Since the bonding of sintered products is provided by the sintering process itself, they may not contain a dedicated binder. The sintering of iron-containing fine powder may only be possible at high temperatures around 1000 - 1300 °C, sometimes reaching temperatures of 1500 °C, so sintering plants require a large amount of solid fuel mixed with the iron-containing material. The sinter mixture used in the sintering process may include, for example, iron ore fines, fluxes, solid fuels, and recycled fines from the sintering plant itself or blast furnaces. Currently, sintered products are the cheapest iron-containing charges for blast furnaces. They are generally cheaper than pellets because the preparation of the raw materials is simpler than that for pellets. However, given the CO2 emission reduction requirements imposed on the steel industry, the sintering method has the disadvantage of producing far more CO2 emissions than pellet production. This is due to the solid fuels (such as powdered coke and anthracite) and gaseous fuels (such as steelmaking gases) required to maintain the high temperatures necessary for the sintering process. [Overview of the Initiative] [Problems that the invention aims to solve]

[0003] Therefore, the object of the present invention is to facilitate a sintering process that reduces the consumption of fossil fuels. This object is achieved by the method according to claim 1. [Means for solving the problem]

[0004] The present invention provides a method for supplying raw materials to a sintering plant. The raw materials can also be called feed material or feedstock, i.e., materials supplied / used in a sintering plant for sintering. The type of sintering plant is not limited within the scope of the present invention. In particular, a sintering plant may be configured as a sintering plant or a pelletizing plant. The sintered products, i.e., the sintered products or pellets of each sintering plant, are typically intended as ferrous burden materials for charging into blast furnaces, etc.

[0005] According to the method of the present invention, the mixed material is used to supply an iron-based loading material, in which case the mixed material comprises a mixture of granular iron-containing material, generally iron ore, and pyrolised granular biomass. In other words, the mixed material is used to provide at least some of the material used in a sintering process. As described below, the mixed material may in some cases not be used as is, but only after mechanical treatment. In other cases, the mixed material can be used in the sintering process in its original form.

[0006] In other words, the present invention proposes the use of a mixture of granular iron-containing material and pyrolyzed granular biomass as a feed material (feed raw material) for a sintering plant (particularly a sintering plant or pelletizing plant). The expression "mixture of granular iron-containing material and pyrolyzed granular biomass" means that the two types of granules are mixed rather than transported and supplied to the sintering plant individually. Mixing can be performed at the point of use, i.e., hundreds or thousands of kilometers away from the sintering plant, and transporting the particles as a mixture of iron and biomass offers many advantages, detailed below. Generally, a mixture of granular iron-containing material and pyrolyzed granular biomass can be a bulk mixture, i.e., the granules are simply bound / mixed together, possibly by some mechanical agitation in a container. However, the term mixture also includes cases where the mixture of granular iron-containing material and pyrolyzed granular biomass is processed to form agglomerates. In the former case, the supply material supplied to the sintering plant is bulk / powdered material of granular iron-containing material and pyrolyzed granular biomass. In the latter case, the supply material supplied to the sintering plant takes the form of agglomerates (or agglomerates) containing granular iron-containing material and pyrolyzed granular biomass.

[0007] The type of sintering plant is not limited within the scope of this invention. The term “sintering plant” is used here to include machines or plants that perform material sintering (or frittage), i.e., heating granular materials to their liquefaction point without melting them, thereby forming solid masses. Sintering plants and pelletizing plants, as known in the steel industry, are two types of sintering plants that involve “sintering processes.”

[0008] According to this method, the mixed material includes pyrolysis biomass, the latter generally being charcoal. Typical pyrolysis temperatures are between 250 and 550°C, and therefore the term “pyrolysis” as used herein also includes milder pyrolysis known as torefaction. However, the biomass may be any plant or animal material. For simplicity, this specification generally refers only to charcoal. Throughout this specification, it will be understood that the term “charcoal” may be replaced with “pyrolysis biomass.” Similarly, the term “iron ore” may be replaced hereafter with “iron-containing material.”

[0009] Iron ore and charcoal are present in the mixed material in particulate form, i.e., as particles or pieces. While particle size is generally not limited within the scope of this invention, certain particle sizes are preferred, as will be discussed below. Iron ore as used in this application generally includes any iron-containing material, such as iron oxides like magnetite (Fe3O4) or hematite (Fe2O3), usually along with gangue minerals and waste or residual materials. Charcoal can be any carbon-containing material produced by removing water and volatile components from plant materials such as biomass, usually wood, organic waste and / or residual biomass, and / or SRF material (solid recovered fuel). Charcoal particles can have a relatively high carbon content, for example, 65% or more by weight, 70% or more by weight, or 75% or more by weight.

[0010] To obtain a mixed material, at least granular iron ore and granular charcoal are provided and then mixed to obtain the mixed material. Mixing can be carried out in various ways, such as actively by mechanically mixing the iron ore and charcoal particles (plus any other components) in a suitable container. Suitable apparatus includes pin mixers, paddle mixers, or rotary drum mixers. Mixing may also be carried out more or less passively, for example, by pouring the iron ore particles and charcoal particles into a container simultaneously, at least some mixing can be achieved. Other suitable mixing methods known in the art can also be used. If necessary, mixing can be combined with loading into a transport container such as a truck, container, train wagon, or ship. This may be in the form of passive mixing described above, or in combination with active mixing immediately before or after loading the granular material into the transport container.

[0011] In several embodiments, the volume percentage of the granular iron-supported material in the mixed material may be between 5 and 80 volume%.

[0012] The method of the present invention has several advantages. Firstly, since charcoal is produced without the use of (usually) fossil fuels, it can be considered CO2 neutral. At least a portion of the fuel required for the sintering process is provided by the charcoal contained in the mixed material, so effective CO2 emissions can be significantly reduced. Other advantages relate to the handling and transportation of the charcoal-containing mixed material. Because charcoal production requires a large amount of biomass, it is almost impossible to have charcoal production facilities and sintering plants in the same geographical location. Therefore, charcoal needs to be transported. In this regard, using a mixed material containing iron ore particles and charcoal particles reduces the necessary safety precautions compared to charcoal itself. Charcoal is a combustible product and usually requires high safety procedures and precautions. The combustibility can be significantly reduced, partly depending on the proportion of charcoal contained in the mixed material. Of course, this also depends on any other components of the mixed material. Furthermore, pure charcoal has a very low density (approximately 0.25 g / cm³).3 Typically, the high proportion of fine particles makes handling complicated due to dust discharge at discharge points. After the charcoal particles are mixed with iron ore particles and other components as needed, the amount of fine particles and dust discharge can be reduced. This is due to different factors, such as the fact that denser iron ore particles prevent embedded charcoal particles from being blown away, and the iron ore particles become wet, which can at least partially restrain the charcoal fine particles in the mixture by the liquid contained in the iron ore particles.

[0013] This makes charcoal usable as a mixed material for long-distance transport. This long distance can be defined as including distances of at least 100 km, preferably at least 500 km, and most preferably several thousand km. Therefore, charcoal can be transported, for example, from Brazil or Canada to the United States, or from Brazil, Canada, the United States, Indonesia, or Russia to Europe. Long-distance transport is preferably carried out by train or ship.

[0014] According to one embodiment, the mixed material is used in the form of compound bodies, where each compound is solid and coherent and contains granular iron ore and granular charcoal. Each compound is solid and coherent, meaning that the individual particles are bound together to form a compound, but the method of binding these particles is not limited thereto. In particular, each compound can be considered as an aggregate or conglomerate containing these particles. The iron ore particles and charcoal particles are bound together as part of the compound. To that extent, the compound is not homogeneous but is at least a combination of granular iron ore and granular charcoal. When charcoal particles are bound as part of the compound, the amount of fine powder and the amount of dust discharged are significantly reduced. Even if the fine powder cannot be completely eliminated, its proportion is usually less than 10% or less than 5%, with the remainder being the unprocessed compound. As described below, the compound may in some cases be used only after mechanical processing, rather than as is. In this case, the raw material exists only in the form of a composite during a certain stage of the supply process, but may be transformed into another form just before being used in the sintering plant. In other cases, the composite can be used for the sintering process in its original form.

[0015] This method may also include the production of a composite. In this case, it includes the following steps prior to supplying the raw materials. In the first step, granular iron ore and granular charcoal are provided. Typically, the iron ore and charcoal need to be broken, crushed, or fragmented, and possibly ground, to obtain a granular form. Similarly, the particles may be sieved to obtain a range of particle sizes. Crushing and / or sieving may be part of providing each granular material.

[0016] In another step, at least iron ore and charcoal are mixed to obtain a mixture. Mixing can be carried out in various ways, such as by actively mechanically mixing the iron ore and charcoal particles (plus any other components) in a suitable container. Suitable apparatus includes pin mixers, paddle mixers, or rotary drum mixers. Mixing may also be carried out more or less passively, for example, by pouring the iron ore particles and charcoal particles into a container simultaneously, at least some mixing can be achieved. Other suitable mixing methods known in the art can also be used.

[0017] In a separate process, composites are formed from the mixture. Each composite can be considered an aggregate or mass containing both iron ore particles and charcoal particles. Depending on the size of the composite, these are called simple aggregates in the form of, for example, blocks, briquettes, pellets, or filter cakes. All composites may be the same size and shape, or they may be of various sizes and / or shapes. This is determined in part by the method of forming the composites. The shape of a single composite may be irregular or regular, for example, spherical, cylindrical, or rectangular. Mixing and forming may be carried out in a single apparatus. The composition of the mixture may be the same as the composition of the mixed material, i.e., the composite. However, its composition may differ, for example, due to liquid components that evaporate during the formation of the composite. Therefore, the terms “mixture” and “mixed material” are not used as synonyms in this context.

[0018] In some embodiments, sufficient bonding of the complex can be achieved, for example, by applying pressure and / or high temperature to a mixture of iron ore and charcoal. In other cases, the degree of bonding achievable by this approach is insufficient. Therefore, this method may further include providing at least one binder, and the mixture is obtained by mixing at least iron ore, charcoal and at least one binder. Even if the manufacturing is not considered as part of this method, each complex contains at least one binder. Each binder serves to enhance the overall bonding of the individual complex. When the mixture is formed, the binder may be present in liquid form and / or dissolved or suspended in the liquid. Once the complex is formed, heat may be applied to the complex to evaporate or chemically transform the liquid component. In some cases, a certain amount of liquid introduced by the binder may be present in the complex.

[0019] According to one embodiment, at least one organic binder is provided. Suitable organic binders include, but are not limited to, various types of cellulose, dairy waste (such as lactose or whey), natural gums (such as guar or xanthan gum), wood-related products (such as hemicellulose or lignin sulfonates), starch, dextrose, molasses (such as sugarcane molasses), and those based on polyacrylamide or polyacrylate structures. Most organic binders are combustible with little to no solid residue during the sintering process. Since they are primarily derived from biomass, they can also be considered CO2 neutral.

[0020] Alternatively or additionally, at least one mineral binder can be provided. Examples of mineral binders, but not limited to, include bentonite, lime, quicklime (CaO), and slaked lime (Ca(OH)2). Generally, mineral binders (i.e., inorganic binders) do not burn during the sintering process but remain as part of the sintered or pelletized product, possibly in a chemically altered form. These binder residues may be irrelevant, harmful, or even beneficial depending on their application in blast furnaces, direct reduction, and / or electric furnaces. In some cases, mineral binders may be more effective than organic binders.

[0021] Preferably, the composite is formed by briquetting. In this context, “briquette” refers to press agglomerating. Pressure is applied to a certain amount of mixture, thereby causing or assisting the aggregation of particles (and possibly other components). Various types of briquetting may be carried out, for example, by extrusion or roll pressing. If extrusion is performed, the primary product will be continuous strands of material that need to be cut or separated to form the composite. Apart from applying pressure, high temperatures can be applied by heating the mixture or a specific part of the briquetting machine in contact with the mixture. Alternatively or additionally, heat can be generated by friction or compression. As described above, the composite obtained from the briquetting process may be called brick, block, briquette or pellet.

[0022] In several embodiments, the mixed material is not aggregated to form a composite, but is used as a bulk mixture of granular iron ore and granular charcoal, and is therefore transported and supplied to a sintering plant in that form. In this case as well, the previously disclosed crushing / crushing / fragmentation / grinding and / or (passive or active) mixing processes would be applied.

[0023] As already mentioned, the locations of charcoal production and sintering plants are usually far apart. They may be in different countries or on different continents. Since charcoal can be transported more easily and safely when combined with iron ore particles in a mixed material, especially when bound together with the iron ore particles in the form of a composite, the mixed material (possibly in the form of a composite) should be formed at or near the charcoal plant. This can greatly avoid the combustion risks and dust generation problems associated with charcoal transport. According to a typical embodiment of the present invention, the mixed material (and in particular, the composite) is formed at a first location, and this method further includes transporting the mixed material to a second location at least 100 km away from the first location. The second location may be the location of a sintering plant. The distance between the first and second locations may be even longer, for example, at least 500 km or several thousand km. In particular, the mixed material can be transported at least partially by train or ship. Under these conditions, the cost-effectiveness of transport largely depends on the total mass being transported. Since charcoal and iron ore (plus any additional components) are transported together, the total mass transported for a given amount of charcoal increases significantly. In other words, by using less charcoal, cost-effective transport (e.g., 200,000 tons) can be achieved. For example, if a sintering plant has a production rate of 6 million TPY and requires 60 kg of charcoal per ton of sintered product, then a total of 360,000 TPY of charcoal is required. If the mixture contains 30% charcoal, cost-effective transport can be carried out once every two months. Such a relatively high transport frequency is beneficial because it reduces the storage capacity required at the first and second locations. To reduce the flammability of the charcoal, it is mixed with an iron-supported material that is not flammable itself. The proposed volume percentage of the iron-supported material in the mixture roughly corresponds to the void volume (volume between charcoal particles) of the charcoal, and is usually between approximately 30 and 55 volume percent. To further reduce flammability, a higher volume ratio of iron ore, even 55% or more, may be preferable. Those skilled in the art will determine the minimum amount on a case-by-case basis, taking into account specific flammability and explosion tests, and based on the properties of the iron-supported material and charcoal.

[0024] However, although there are the above-described advantages due to a charcoal content that is not too high, considering the use of several ore sources and / or charcoal sources in production, for the sintering process, it is desirable for charcoal and iron ore to be present in more or less appropriate ratios, so the charcoal content should not be too low. Therefore, it is desirable for the mixed material to contain at least 1 wt% or 10 wt% charcoal, preferably at least 20 wt%, more preferably at least 30 wt% charcoal. Particularly preferred ranges are 1 - 30 wt%, 5 - 20 wt%, and possibly 10 - 20 wt%. If the mixed material is in the form of a composite, the weight percentage in the mixture forming it may be somewhat lower, for example, because the mixture contains a liquid component that evaporates in the method of forming the composite.

[0025] To benefit from the above-described advantages associated with the reduction of the charcoal content and to provide a sufficient amount of iron ore for the sintering process, it is advantageous for the mixed material to contain at least 20 wt%, preferably at least 30 wt%, more preferably at least 50 wt% iron ore. Again, if this refers to a composite, the weight percentage in the mixture forming these composites may be somewhat lower, for example, due to the evaporation of the liquid component.

[0026] Generally, the formation of coherent compound bodies, which can be regarded as aggregates or agglomerates, is easier when the charcoal particles are relatively small. Also, the smaller the size of the individual charcoal particles, the more the effectiveness of the charcoal in the sintering plant process can be enhanced, regardless of whether the mixed material is in the form of a composite. Therefore, it is preferable for the granular charcoal to have a size of less than 10 mm, preferably less than 5 mm, more preferably less than 3.5 mm for the D90 sieve. In other words, at least 90% of the charcoal particles have a maximum size of less than 10 mm (or 5 mm or 3.5 mm respectively).

[0027] In the method of the present invention, various types of iron-containing materials, generally iron ore, can be used as mixed materials (for example, in composites or aggregates). According to one embodiment, the granular iron-containing material includes sinter feed particles, which have a sieve size of at least a large portion between 0.1 mm and 6.3 mm. "Sinter feed" is a term commonly used for iron-containing raw materials having relatively large / coarse particle sizes as described above. It is generally produced from iron ore and, due to its chemical properties, is suitable for operation in blast furnaces, direct reduction and / or electric furnaces without further modification. In other words, the iron content in iron ore is relatively high from the start, i.e., the gangue material is relatively well separated from the iron compounds, so the gangue material content is low. When we say "at least a large portion" for sieve sizes between 0.1 mm and 6.3 mm, this means that at least 80% or at least 90% of the particles have a maximum size of 0.1 mm to 6.3 mm.

[0028] Alternatively, in the case of a pelletizing plant, or additionally in the case of a sintering plant, the granular iron ore may include iron-containing material with smaller particle sizes, such as concentrate and / or pellet feed particles (hereinafter simply referred to as "pellet feed"), which have a sieve size of at least 0.15 mm or less. Here again, this refers to at least 80% or at least 90% of the particles having a maximum size of less than 0.15 mm. "Pellet feed" is a high-purity iron ore material resulting from the improvement of low-grade iron ore, which has a low iron content and poor separation of iron compounds from gangue material. However, by grinding the iron ore or separating it by other means to reduce the particle size, it becomes possible to separate particles with a sufficiently high iron content from particles with a low (or no) iron content. The particles with a high iron content can be used as pellet feed. As is common in sintering plants, the quality of sintered feed is deteriorating because suitable iron ore is no longer readily available. This can be compensated for by including at least a portion of the pellet feed.

[0029] As described above, the size of the composite is generally not limited within the scope of the present invention. However, preferably, the maximum size of the composite is between 1 mm and 500 mm. If the maximum size is below or above this range, the production and / or handling of the composite becomes difficult. Small composites, for example, those with a maximum size of less than 15 mm, can be called "pellets", while larger composites, for example, those with a maximum size between 15 mm and 100 mm, can be called "briquettes", and even larger composites can be called "blocks" or "bricks". As described above, the individual composites can be spherical, cylindrical, cuboid, flat or irregular in shape.

[0030] Particularly when the maximum size of an individual composite is small, it is conceivable that the composite can be used as such, i.e., without further processing, in a sintering plant. According to another embodiment, the composite is fragmented before being used in a sintering plant. The fragmentation can be carried out, in particular, by pressing and crushing the composite. The fragmentation process can also effect a partial or complete separation of the iron ore particles from the charcoal particles and possibly also the fragmentation of the individual charcoal and / or iron ore particles. In particular, when using the material in a pelletizing plant, the material is usually crushed before entering the sintering process.

[0031] In sintering plants, there are two main methods for adding a charcoal / iron ore mixture to the sintering process. The charcoal / iron ore mixture can be added to a sintered bedding pile. A sintered bedding pile typically consists of horizontal layers of different materials. When using a sintered bedding pile, reclaimers usually remove the material perpendicular to the layers. This allows for good mixing of the materials, and longer mixing periods (e.g., 1 to several weeks). In this case, the charcoal / iron ore mixture can be easily added directly. Precautions regarding segregation of charcoal and iron ore particles during stacking are thus limited. Nevertheless, in cases of stacking, especially involving dosing bins, the effects of segregation described below must also be considered. A second possibility for introducing a charcoal / iron ore mixture into a sintering plant process is in the sintering plant stockhouse. In this case, the mixture is administered during the sintering process using special dosing systems such as loss-in-weight feeders, weighing belt conveyors, and screw feeders. It is crucial that the charcoal / iron ore mixture is not segregated, as segregation can lead to uncontrollable compositional problems in the sintered mixture during the sintering process.

[0032] In the case of pelletizing plants using charcoal / iron ore mixtures, the second possibility does not apply because the material needs to be ground before the sintering process. Therefore, the effects of segregation as described above are irrelevant.

[0033] Therefore, fragmentation of the composite is preferably carried out shortly before the fragmented material is introduced into the sintering process of the sintering plant, thereby avoiding or minimizing any problems related to the generation or combustion of charcoal dust. Preferably, crushing of the composite may be carried out at the outlet of the storage silo just upstream of the dosing device. Rarely, the mixed material may be fragmented even if it is not in the form of a composite. On the other hand, regarding the fragmentation of the composite when introduced into a pelletizing plant, all components are ground separately or together in a grinding unit before the sintering process.

[0034] The mixed material can preferably be used in the sintering process with little to no additional material. That is, the mixed material can be the main component of the raw material supply for the sintering process. However, in practice, the mixed material can provide at least 10% by weight of iron-containing material and at least 5%, preferably at least 10, and more preferably at least 20% by weight of carbon-containing material (fixed carbon) for the sintering process in a sintering and pelletizing plant. Particularly in a sintering plant, it is preferable that the amount of pellet feed to be added to the raw material is only a small amount, which corresponds to, for example, 90% by weight or less, and possibly less than 60% by weight of iron-containing material. The mixed material can provide at least 10% by weight, preferably at least 40% by weight, or more preferably at least 60% by weight of carbon-containing material. It is also preferable that anthracite and / or powdered coke do not need to be added to the raw material, or 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.

[0035] In this specification, the term "sintered" refers to an aggregate of ore formed by heat treatment, or so-called sintering. The resulting product may be, for example, pellets or sintered products.

[0036] As already stated, the term "sintering plant" in this specification encompasses sintering processes, particularly ore agglomeration plants including pelletizing plants and sintering plants in general.

[0037] This can typically be achieved by providing a mixture to maintain the sintering process during heat treatment in a furnace, typically at 1000-1400°C and typically in an acidic atmosphere (where a considerable amount of O2 is still present in the gas atmosphere), similar to conventional pelletizing and sintering processes. [Brief explanation of the drawing]

[0038] Next, preferred embodiments of the present invention will be described by reference to the accompanying drawings. [Figure 1] This diagram illustrates the material flow of a method according to the first embodiment of the present invention related to a sintering plant. [Figure 2] This is a processing flow chart of the method shown in Figure 1. [Figure 3] This is an explanatory diagram of the material flow of a method according to the first embodiment of the present invention related to a pelletizing plant. [Figure 4] Figure 3 is a processing flow diagram of the method. [Figure 5] This is an explanatory diagram of the material flow of a method according to a second embodiment of the present invention related to a sintering plant. [Figure 6] Figure 5 is a processing flow chart of the method. [Figure 7] This is an explanatory diagram of the material flow of a method according to a second embodiment of the present invention related to a pelletizing plant. [Figure 8] Figure 7 is a processing flow chart of the method. [Modes for carrying out the invention]

[0039] Figure 1 is a material flow diagram showing a first embodiment of the present invention applied to a sintering plant, and Figure 2 is a processing flow diagram of this method. Next, the present method will be described with reference to both figures. In the first step of this method, granular iron-containing material iron ore 1, thermally decomposed granular biomass char 2, and binder 3 are provided at 100. For the sake of simplification, this explanation uses iron ore 1 as the iron-containing material 1 and charcoal 2 as the thermally decomposed biomass 2. However, it should not be understood as being limited to these examples.

[0040] Granular iron ore 1 is provided from an iron-containing material source such as an ore mine 5, while granular charcoal is supplied from a charcoal plant 6. In this embodiment, granular iron ore 1 includes sintered feed having a particle size between 1 and 6.3 mm, and pellet feed having a particle size of less than 1.5 mm. Alternatively, only sintered feed or pellet feed may be used, respectively. Charcoal 2 may be produced by the slow thermal decomposition of plant material, such as wood, and may have a D90 sieve size of less than 3.5 mm. The charcoal particles may have a relatively high carbon content, for example, 65% by weight or more, 70% by weight or more, or even 75% by weight or more. The binder 3 may be a mineral binder such as bentonite, or an organic binder such as sugarcane molasses. Alternatively, a combination of a mineral binder and an organic binder may be used.

[0041] In the next step, at 110, granular iron ore 1, granular charcoal 2, and binder 3 are mixed to form a mixture. The mixture may contain at least one liquid component, which may be part of the binder 3 or may be added to facilitate the mixing process. At 120, aggregates 7 (agglomerates) are formed from the mixture in an aggregate unit 4, which may also perform the mixing. The aggregate unit 4 may be located near or even inside the charcoal plant 6 to minimize the transport distance of the charcoal 2. However, more preferably, the aggregate unit 4 may be located near an iron ore mine or a transport port. If necessary, the formed aggregates 7 may be exposed to high temperatures to harden the binder 3 or to evaporate the liquid component. The aggregates 7 thus formed contain granular iron ore 1, granular charcoal 2, and binder 3 and may potentially undergo chemical changes from their initial form due to the hardening process, etc. The aggregates 7 may be, for example, rectangular parallelepipeds with a maximum size of 10 cm.

[0042] The completed aggregate 7 is a solid, cohesive composite that is well-suited for storage and transport. In particular, since the charcoal 2 is bound to the aggregate, no special safety precautions are required, and the risk of combustion related to pure charcoal 2 is virtually eliminated. The completed aggregate 7 is transported by a first land transport vehicle 11 (e.g., by rail or truck) to a first port 12 (130), where it is transferred to a ship for long-distance overseas transport 13 (140). If necessary, the first land transport vehicle 11 may not be required if the briquetting units are located near the first port 12. After the ship arrives at the destination, a second port 14, the aggregate 7 is unloaded and transported again. Subsequently, they are transported by another land transport vehicle 15 to a steel mill 16, which includes crushing units 17 and a sintering plant 20 (150). The aggregate 7 is crushed (160) in the crushing unit 17 as a preparation for use in the sintering plant 20, thereby obtaining a mixture of smaller particles as crushed material 18. Crushing may be omitted in some cases, for example, when the size of the aggregate 7 is very small. The majority of the crushed material 18 is usually pure iron ore particles or pure charcoal particles with at least a small amount of binder, while other particles may include at least one charcoal particle bound together with the iron ore particles. There may be dedicated bins (not shown) in the storage facility of the sintering plant 20 where the aggregates 7 are stored. They can then be placed on a conveying system (e.g., a belt conveyor) that dispenses a quantitative amount, crushes it, and supplies it to the mixing drum of the sintering plant 20. Instead of adding the mix material in the storage facility of the sintering plant, they can also be added directly to the sintered body mixing bedding pile further downstream or upstream.

[0043] The crushing unit 17 can be located relatively close to the sintering plant 20, and special precautions can be taken for the transport of the crushed material 18 from the crushing unit 17 to the sintering plant 20 to avoid problems of dust generation or combustion risk associated with charcoal particles. Additional components 19 are added at 170, which may include, for example, pellet feed and / or sintering feed to supplement iron ore from the aggregate 7, fossil fuels such as anthracite and / or powdered coke, non-fossil fuels, or a combination of both to meet energy requirements for the sintering process, lime, water, or other suitable additives. Then, a sinter bed is formed at 180, and sintering is carried out at 190. It is worth noting that the crushed material 18 is supplied to a storage facility for mixing with the additional components 19. Alternatively, the crushed material 18 may be added directly to the sintering bed. The charcoal from the aggregate 7 may be all of the fixed carbon-containing material for the sintering process. However, this is usually only a portion of the carbon-containing material, for example, a carbon-containing material between 20% and 90% by weight. In any case, the amount of fossil fuels is significantly reduced, if not eliminated, and therefore the sintering process is close to CO2 neutral. As a result of the sintering process, a sintered product 21a of specified quality is delivered at 200, which can then be used for steelmaking in blast furnaces, direct reduction, electric furnaces, etc. In the same context as the first embodiment of the method of the present invention, Figure 3 shows a material flow diagram, where, at a second location 31, the compound mix 7 is introduced into a sintering plant 20, which has pellets as product 21b instead of sintered product 21a, while Figure 4 is a corresponding processing flow diagram of this method. The two inventive methods of the first embodiment are similar, except that the main difference is that all components for sintering, additional material 19 and crushed material 18 or composite, aggregate 7 must undergo further fragmentation, more specifically grinding 171. All components are then ground in a crushing unit 17 to a particle size typically D80 < 0.045 mm, and spherical pellets typically 6 to 16 mm in diameter are formed before sintering 190 is carried out 180.After sintering 190, pellet products 21b of specified quality are delivered in 200, which can then be used for steelmaking in blast furnaces, direct reduction furnaces and / or electric furnaces, etc.

[0044] Figure 5 is a material flow diagram showing a second embodiment of the present invention applied to a sintering plant, and Figure 6 is a processing flow diagram of this method. Since this embodiment is similar to the first embodiment to some extent, it will not be described in detail again. In the first step, granular iron ore 1 from an iron ore mine 5 and granular charcoal 2 from a charcoal plant are provided in 100. The particle size and composition may be the same as in the first embodiment.

[0045] If necessary, at 105, granular iron ore 1 and / or granular charcoal 2 may be transported by (first) land transport 9 to the location 30 of the mixing container 10. At 110, the granular iron ore 1 and granular charcoal 2 are mixed in the mixing container 10 to obtain a binder-free particle mixture 8. The mixing can be carried out in an active or passive manner by simply pouring the granular iron ore 1 and granular charcoal 2 into the mixing container 10 simultaneously. In this way, the particle mixture 8 is a bulk mixture of two types of granular material (iron and charcoal) and is transported in this bulk form. This embodiment is distinguished from that of Figure 1 in that no aggregates are formed (and therefore there are no aggregate units 4). However, the particle mixture 8 may contain some liquid introduced along with the iron ore 1 if necessary. Such a liquid helps to temporarily bind some charcoal powder and dust, thus reducing the risk of combustion associated with the otherwise resulting granular charcoal 2. In this way, the particulate mixture 8 is transported in bulk particle form to a first port 12 by land transport 11 (e.g., by rail or truck) (130), where it is transported to a ship for long-distance overseas transport 13 (140). The mixing container 10 may be part of a railcar, truck, etc., used in the land transport 11. Land transport 11 may be unnecessary if necessary when the mixing container 4 is at the first port 12. At the second port 14, the particulate mixture 8 is unloaded and transported again. Subsequently, it is transported (at 150) by another land (or river or other) transport 15 to a steel mill 16, which includes a sintering plant 20 where the particulate mixture 8 is provided as raw material / supply material. The particulate mixture 8 does not need to be crushed and can be used as is. Additional mixing materials can be added in the storage facility (not shown) of the sintering plant, or they can be added further downstream or further upstream directly to the sintered body mixing bedding pile.

[0046] The additional component 19 is added at 170 as described in relation to the first embodiment, the sintering bed is formed at 180, and sintering takes place at 190. It is again worth noting that the particle mix 8 can be supplied to the stockpile for mixing with the additional component 19. Alternatively, the particle mix 8 may be added directly to the sintering bed. The sintered product 21a of specified quality is delivered at 200 and can now be used for steelmaking in blast furnaces, direct reduction, electric furnaces, etc.

[0047] In the same context as the second embodiment of the method of the present invention, Figure 7 shows a material flow diagram, where, at the second location 31, the particle mixture 8 is introduced into a sintering plant 20, which has pellets as product 21b instead of sintered product 21a, while Figure 8 is a corresponding processing flow diagram of this method. The two inventive methods of the second embodiment are similar, except that all components for sintering, additional materials 19 and particle mixture 8 must be further fragmented, more specifically ground 171. In this case, all components are ground at the crushing unit 17 to a particle size typically D80 < 0.045 mm, and spherical pellets typically 6 to 16 mm in diameter are formed before sintering 190 is performed. After sintering 190 is performed, pellet product 21b of specified quality is delivered 200, which can then be used for steelmaking in a blast furnace, direct reduction furnace or electric furnace, etc.

[0048] In both embodiments, long-distance transport is carried out by ship. However, the present invention also includes long-distance transport by train. In this case, transport can be carried out in a single journey directly from a first location to a second location. [Explanation of Symbols]

[0049] 1. Iron-containing materials, iron ore 2. Pyrolytically decomposed biomass, charcoal 3 Binders 4 Collective Units 5 Iron Ore Mine 6 Charcoal Plant 7 Complex, aggregate 8 particle mixture 9. Land transport 10 Mixing container 11. Land transport 13. Land transport 12 ports 13 Long distance overseas transportation 14 port 15 Means of transportation 16 Steelworks 17. Crushing or grinding unit 18. Crushed or ground material 19 Additional materials 20. Sintering plant (sintering plant or pelletizing plant) 21a Sintered Products 21b Pellet Products 30 First Place 31. Second Place

Claims

1. A method for supplying raw materials to a sintering plant (20) that performs material sintering, characterized in that a mixed material (7, 8) is used to supply raw materials, the mixed material (7, 8) comprises granular iron-containing material (1) and pyrolyzed granular biomass (2), the granular iron-containing material (1) and pyrolyzed granular biomass (2) exist in a mixed form in which they are mixed with each other, the mixed material (7, 8) is transported to the sintering plant (20) over a long distance of at least 100 km, and the mixed material (7, 8) contains at least 20% by weight of iron-containing material (1).

2. The method according to claim 1, characterized in that the long distance is at least 500 km.

3. The method according to claim 1 or 2, characterized in that the mixed materials are transported over long distances by train or ship.

4. The method according to any one of claims 1 to 3, characterized in that the mixed material is used in the form of a composite (7), each composite (7) is solid and cohesive and contains granular iron-containing material (1) and pyrolyzed biomass (2).

5. Prior to supplying raw materials, The present invention provides granular iron-containing material (1) and thermally decomposed granular biomass (2) (100); To obtain a mixture, at least an iron-containing material (1) and thermally decomposed biomass (2) are mixed (110); and A complex (7) is formed from the mixture (120). The method according to claim 4, characterized by including the following.

6. The method according to claim 5, further comprising providing at least one binder (3) (100), and the mixture being obtained by mixing at least an iron-containing material (1), pyrolyzed biomass (2), and at least one binder (3) (110).

7. The method according to any one of claims 4 to 6, characterized in that the aggregate is formed by briquettes.

8. The method according to any one of claims 1 to 7, characterized in that the mixed material is supplied to a sintering plant in bulk form.

9. The method according to any one of claims 1 to 8, characterized in that the mixed material (7, 8) contains at least 1% by weight of pyrolysis biomass (2).

10. The method according to any one of claims 1 to 9, characterized in that the mixed material (7, 8) contains at least 30% by weight of an iron-containing material (1).

11. The method according to any one of claims 1 to 10, characterized in that the volume percentage of granular iron-supported material in the mixed material is between 5 and 80 volume%.

12. The method according to any one of claims 1 to 11, characterized in that the pyrolyzed granular biomass (2) has a D90 sieve size of less than 10 mm.

13. The method according to any one of claims 1 to 12, characterized in that the granular iron-containing material (1) comprises sintered feed particles having a sieve size between 0.1 mm and 6.3 mm, at least for the majority of the particles.

14. The method according to any one of claims 1 to 13, characterized in that the granular iron-containing material (1) comprises pellet feed particles having a sieve size of at least a majority of less than 0.15 mm.

15. The method according to any one of claims 4 to 12, characterized in that the composite (7) has a maximum size between 1 mm and 500 mm.

16. The method according to any one of claims 4 to 13, characterized in that the composite (7) is fragmented (160) before being used in a sintering plant (20).

17. The method according to any one of claims 1 to 16, characterized in that the mixed materials (7, 8) provide at least 10% by weight of an iron-containing material and at least 5% by weight of a carbon-containing material for a sintering process (190) in a sintering plant (20).

18. The method according to any one of claims 1 to 17, characterized in that the iron-containing material (1) is iron ore (1), and / or the pyrolyzed biomass (2) is charcoal (2), and / or the composite (7) is an aggregate (7) or agglomerate.

19. A method for operating a sintering plant, characterized in that iron-containing material and carbon-containing material are supplied to the sintering plant, and they are heated in a furnace to maintain the sintering process in order to form a solid iron-containing product, and the sintering plant receives the mixed material in a manner described in any one of claims 1 to 18.

20. The method according to claim 19, wherein the mixed material (8) is a bulk mixture of granular iron-containing material (1) and thermally decomposed granular biomass.

21. The method according to claim 19, wherein the mixed material (7) comprises a granular iron-containing material (1) and an aggregate of thermally decomposed granular biomass.

22. The method according to any one of claims 19, 20, or 21, wherein, before being fired in a furnace under an oxidizing atmosphere, the mixed materials (7, 8) are crushed and / or combined with additional components and assembled as necessary, and the resulting sintered product is crushed.

23. The sintering plant is configured as a pelletizing plant, and the method according to any one of claims 19, 20, or 21 includes the steps of grinding a mixed material to form raw iron ore pellets therefrom, and charging the raw pellets into an indurating furnace under an oxidizing atmosphere and firing them to form hardened pellets.

24. The method according to claim 23, wherein additional materials, including a mixed material and a binder material, are ground in a crushing unit (17) of a pelletizing plant, and from the ground materials, raw pellets with a diameter of approximately 6 to 16 mm are formed in a spherical shape.

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