Method for modifying powder properties and method for producing sintered ore

Abstract

The present invention provides a powder property modification technique capable of performing heating with good productivity when granulating and heating an aqueous bulk material. The powder property modification method of the present invention includes: when granulating and heating an aqueous bulk material, adding a medicament in which any one or more selected from a high-molecular condensing agent, an inorganic condensing agent, and a high-molecular water-absorbing material is / are a main component to the aqueous bulk material before or during the granulation process, and at this time, adjusting the amount of the medicament to be added in accordance with the moisture content of the aqueous bulk material or an operation index related to the moisture content of the aqueous bulk material. The sinter manufacturing method of the present invention includes: a powder property modification process in which the amount of the medicament to be added is adjusted in accordance with the moisture content of a sintering raw material or an operation index related to the moisture content of the aqueous bulk material according to the powder property modification method; a granulation process in which the sintering raw material whose properties have been modified is granulated using a granulator; and a sintering process in which the granulated sintering raw material is sintered using a sintering machine.

Description

Technical Field

[0001] This invention relates to a method for modifying the properties of water-containing powders to eliminate undesirable conditions caused by moisture generated during granulation and heating of water-containing bulk materials. Furthermore, this invention relates to a method for manufacturing sinter using this modification method. Background Technology

[0002] Powders and granules of various ores, byproducts of ore refining or steelmaking, slag, and byproducts of petroleum distillation / rectification are called bulk materials. Bulk materials mostly contain fine powders. Therefore, they are granulated, sintered, and adjusted to a given particle size for use as raw materials. In the steel industry, powdered iron ore is mixed with limestone and coke powder, and after adding water, it is granulated into pseudo-particles of a given particle size. It is known that feeding pseudo-particles of appropriate size and shape to the sintering machine can ensure permeability and improve the productivity of sintered ore.

[0003] On the other hand, bulk materials are stored in open areas or transported under conditions exposed to the atmosphere. Consequently, continuous rainfall can cause these bulk materials to retain a large amount of moisture. This state is called hydrated bulk material. It is known that when granulating such hydrated bulk materials, it is necessary to manage the appropriate moisture content; excessive moisture in the granules reduces permeability, thus decreasing the productivity of the granules and causing a decline in quality. Furthermore, removing moisture sometimes requires excessive equipment investment. For example, methods such as mixing with pre-stored dry raw materials in silos can be used.

[0004] In the past, the methods disclosed in patent documents 1 to 3 have been used to address this problem.

[0005] Patent Document 1 discloses a method for processing sintering raw materials. This method inhibits the adhesion of low-alumina content ores to each other by uniformly mixing high-alumina content ores with low-alumina content ores, thereby suppressing the uneven presence of alumina. This technology involves adding an adhesion inhibitor to the low-alumina content ores during granulation to obtain a mixed powder in which at least the low-alumina content ores and the high-alumina content ores are uniformly dispersed.

[0006] Patent Document 2 discloses a method for handling water-containing bulk materials, which eliminates unloading obstacles on belt conveyors caused by unavoidable slurry-like water inrush during the unloading of water-containing bulk materials. In this technology, by attaching a coagulant to the water-containing bulk materials, the generation of water inrush during the unloading of the bulk materials can be suppressed, thereby improving operability.

[0007] Patent document 3 discloses a technique for adding coagulants and water-absorbing materials to water-containing bulk materials to retain moisture in the powder and suppress equipment stoppages, spillage during transportation, backflow, and collapse of storage piles caused by adhesion. Since the granulation method applied to sintering raw materials can suppress the solidification of small-diameter powder particles in water-containing bulk materials while maintaining an uneven state, the strength of the granules is not reduced, and it contributes to improving the yield, uniformity of mineral structure, and productivity during sintering.

[0008] Existing technical documents

[0009] Patent documents

[0010] Patent Document 1: Japanese Patent Application Publication No. 2017-125247

[0011] Patent Document 2: International Publication No. 2015 / 151524

[0012] Patent Document 3: International Publication No. 2024 / 004298 Summary of the Invention

[0013] The problem the invention aims to solve

[0014] However, the aforementioned conventional technologies have the following problems. For example, regarding countermeasures such as mixing pre-stored dry raw materials in silos or the like when the bulk material containing moisture contains excessive moisture, there are problems with the limited size of the silos, the short duration of operation, and the limited effectiveness. As for countermeasures such as storing all raw materials in a roofed space for extended periods to reduce moisture content, the increased land and equipment costs required for constructing necessary plant facilities become a problem.

[0015] Furthermore, Patent Document 1 does not demonstrate that managing reagent concentration contributes to the productivity of sintered ore. There is a problem that it does not consider applications for single-variety varieties with no difference in alumina content.

[0016] Furthermore, the technology described in Patent Document 2 focuses on the operability of the powder and does not consider the correlation between sintering productivity, granulation, and permeability. Additionally, the technology described in Patent Document 3 only describes features that improve sintering productivity and does not consider appropriate reagent concentrations.

[0017] In these prior art technologies, the improvement effect on air permeability caused by water from the raw material source or rainfall in the ironmaking plant exceeding the operating range of suitable moisture content for granulation is insufficient. This technology improves sintering productivity or grade by improving air permeability at moisture levels exceeding the suitable moisture content for granulation, which these existing technologies cannot handle.

[0018] This invention was made in view of the above circumstances, and its object is to provide a powder property modification technology that enables productive heating during granulation of hydrated bulk materials and during heating processes ranging from heating for the purpose of evaporating water to high-temperature heating processes accompanied by reactions. In particular, this invention achieves improved permeability in a high moisture range that was previously unattainable with conventional technologies, and its object is to provide a method for manufacturing sintered ore using hydrated bulk materials as raw materials and improving productivity.

[0019] Problem Solving Methods

[0020] The powder property modification method of the present invention advantageously solves the above problems by comprising: when granulating or heating a water-containing bulk material, adding an agent with one or more of the following as main components to the water-containing bulk material before granulation or during the granulation process. At this time, the amount of the agent added is adjusted according to the moisture content of the water-containing bulk material or an operating index related to the moisture content of the water-containing bulk material.

[0021] It should be noted that, in the powder property modification method of the present invention, it is more preferable that the above-mentioned water-containing bulk material is at least one of ore, ore refining or steel manufacturing by-product slag, and petroleum distillation / rectification by-product.

[0022] The present invention advantageously solves the above-mentioned problems by providing a method for manufacturing sintered ore that granulates and heats a sintering raw material containing iron-containing raw material, carbon-containing raw material, and CaO-containing raw material as a water-containing bulk material. The method includes: a powder property modification step, in which the amount of the above-mentioned agent added is adjusted according to the moisture content of the sintering raw material or an operating index related to the moisture content of the above-mentioned water-containing bulk material according to any of the above-mentioned powder property modification methods; a granulation step, in which the morphology-modified sintering raw material is granulated using a granulator; and a sintering step, in which the granulated sintering raw material is sintered using a sintering machine.

[0023] It should be noted that, in the method for manufacturing sintered ore of the present invention, adjusting the amount of reagent added in the powder property modification process according to the permeability index or the operating condition index related to permeability in the above-mentioned sintering process is a more preferred solution.

[0024] The effects of the invention

[0025] According to the powder property modification method of the present invention, when granulating and heating water-containing bulk materials, a coagulant and a water-absorbing material are added accordingly based on the moisture content of the bulk materials. Therefore, the deterioration of air permeability during heating caused by excessive moisture can be suppressed, thus preventing the resulting deterioration in productivity. Furthermore, by improving the diffusivity of the raw materials, effects such as product homogenization can also be achieved. Attached Figure Description

[0026] Figure 1 The graph shows the effect of adding the agent on the relationship between the blended average particle size and moisture content of the granulated particles during the granulation of sintering raw materials.

[0027] Figure 2 The graph shows the effect of adding the agent on the relationship between the air permeability index and the moisture content when the granulated particles are heated.

[0028] Figure 3 The graph shows the effect of adding the agent on the relationship between heating time and moisture content of the granulated particles.

[0029] Figure 4 The graph shows the effect of adding reagents on the productivity of sinter and the moisture content of granulated particles.

[0030] Figure 5 It is a graph showing the relationship between the sinter production rate of the actual equipment and the reagent concentration relative to the moisture content.

[0031] Figure 6 It is a graph showing the relationship between the productivity ratio relative to the suitable moisture value and the agent concentration relative to the moisture content.

[0032] Figure 7 In the figure, (a) is a graph showing the relationship between the amount of water added during granulation of sintering raw materials and the blended average particle size and air permeability during heating, and (b) is a schematic diagram of particle morphology.

[0033] Symbol Explanation

[0034] 1. Iron ore powder

[0035] 2 moisture

[0036] 3. Water film

[0037] 4 water droplets Detailed Implementation

[0038] Hereinafter, embodiments of the present invention will be described in detail. Furthermore, the following embodiments exemplify methods for embodying the technical concept of the present invention and do not limit the structure of the present invention to the following content. That is, various modifications can be made to the technical concept of the present invention within the scope of the claims.

[0039] In this embodiment, a method for manufacturing sintered ore using a powder property modification method will be described as an example. The equipment suitable for the sintered ore manufacturing method of this embodiment includes a reagent addition device, a granulator, and a sintering device. The sintering device includes a sintering machine, a crusher, and a control device. In this embodiment, examples of bulk materials containing water include ores, ore refining, slag (a byproduct of steelmaking), and byproducts of petroleum distillation / rectification. Examples of ores include iron ore, coal, limestone, dolomite, silica, magnesite (a MgO source), and ores containing nickel and manganese.

[0040] For pharmaceutical additive equipment, it is preferable to use a dedicated mixer to mix the powdered bulk materials after spraying liquid or spreading the powdered agent. Alternatively, a crusher or heavy machinery-based mixer, or the impact of the conveyor's drop, can be used instead of a dedicated mixer. This mixing process allows the agent to diffuse into the powder. This step is a powder property modification step.

[0041] A granulator granulates sintering raw materials containing iron, carbon, and CaO to produce granulated particles. Granulation water is added to the sintering raw materials during the granulation process. This is the granulation process. The granulated particles produced by the granulator are then transported to the sintering machine. It should be noted that iron-containing raw materials include, for example, iron ore and dust generated in iron smelting plants. Carbon-containing raw materials include, for example, pulverized coke and anthracite. CaO-containing raw materials include, for example, quicklime, limestone, and slag. Furthermore, only the necessary components need to be added.

[0042] Sintering machines, such as Dwight-Lloyd type sintering machines, are equipped with a raw material feeding device, a sintering carriage, a scraper, an ignition furnace, a gas fuel supply device, and a bellows. The raw material feeding device loads the granulated particles into the sintering carriage.

[0043] The sintering carriage is a ring-belt moving sintering carriage. When granulated particles are loaded into the sintering carriage from the raw material supply device, a loading layer of sintering raw material is formed inside the sintering carriage. A scraper smooths the surface of the loading layer and makes the thickness of the loading layer consistent with the preset target layer thickness. This process is the loading layer formation step.

[0044] An ignition furnace is located downstream of the raw material supply unit to ignite the carbonaceous raw materials contained in the surface layer of the charging bed. A gaseous fuel supply unit supplies gaseous fuel to the surface layer of the charging bed. For example, city gas (LNG) is supplied as the gaseous fuel. The gaseous fuel supplied from the gaseous fuel supply unit is not limited to city gas; any combustible gas selected from blast furnace gas, coke oven gas, blast furnace-coke oven mixed gas, converter gas, natural gas, methane gas, ethane gas, propane gas, shale gas, and mixtures thereof can be used.

[0045] A bellows is positioned below the sintering carriage to draw air downwards from the loading layer formed within the carriage. As the bellows draws air downwards, the combustion and melting zones within the loading layer move downwards. Simultaneously, by drawing air downwards, gaseous fuel supplied from the gas fuel supply device is introduced from the surface of the loading layer into it. As the sintering carriage moves, the combustion and melting zones within the loading layer move downwards, thereby sintering the sintering material in the loading layer. Through the sintering of the sintering material, a sintered cake is obtained. This process is the sintering step.

[0046] The crusher breaks down the sinter cake discharged from the sintering machine to produce crushed sinter cake. The crushed sinter cake is then cooled and granulated to produce sintered ore. This process is the crushing step. The above-mentioned loading layer formation step, sintering step, and crushing step together constitute the sintering process.

[0047] The control device is a general-purpose computer, such as a workstation or personal computer, that has a control unit and a storage unit. The control unit, such as a CPU, controls the operation of the pharmaceutical dosing equipment, granulator, sintering machine, and crusher by executing programs read from the storage unit. The storage unit is, for example, an updatable flash memory, a hard drive (built-in or connected via a data communication terminal), a memory card, or other information recording media and their read / write devices. The storage unit stores the programs used by the control unit to perform its various functions, as well as the data used in those programs.

[0048] The control unit calculates permeability indices, such as air permeability resistance, of the sintering raw materials stacked on the sintering cart based on the suction air volume and back pressure of the sintering cart. The control unit then adjusts the granulation conditions of the granulator and the amount of reagent added to the reagent addition equipment based on the calculated permeability index.

[0049] When the granulation conditions of the granulator are changed, the control unit alters the granulation conditions to narrow the particle size distribution width of the granulated particles. When the particle size distribution width narrows, the packing density of the granulated particles loaded into the sintering carriage decreases, thus reducing the packing density of the loading layer. To determine the granulation conditions that narrow the particle size distribution width, granulation tests can be conducted by changing the granulator speed, the amount of sintering raw material fed into the granulator, and the amount of granulation water added. The particle size distribution width of the granulated particles can then be confirmed, and the granulation conditions that narrow the particle size distribution width can be determined.

[0050] Furthermore, the control unit can also increase the amount of CaO-containing raw material incorporated into the sintering raw materials. CaO acts as a binder, thus allowing ungranulated powder that is difficult to granulate to adhere to the granulated particles, reducing the fine particles in the particle size distribution. Therefore, when the amount of CaO-containing raw material is increased, the particle size distribution width of the granulated particles narrows. It should be noted that in the sintering ore manufacturing method of this embodiment, the increase in the amount of CaO-containing raw material is also included in the change of granulation conditions.

[0051] When adjusting the amount of reagent added, the control unit adjusts the amount of reagent added in a way that brings the permeability index of the granulated particles during heating close to a given value. For the amount of reagent added to bring the permeability index, or the operating condition index related to permeability, close to a given value, for example, the moisture content of the bulk material, or the operating index related to the moisture content of the bulk material, can be measured in advance and determined based on that value. Operating conditions related to permeability can also be evaluated using the heat exchange index. During sintering, the index of heat exchange between the high-temperature gas and the target powder or water during the pre-drying process of the coke raw material coal can be used.

[0052] <Granulation and Moisture Content>

[0053] Figure 7 The diagram schematically illustrates the effect of moisture content on the particle size of granulated particles during the granulation of sintering raw materials and on air permeability during heating. In the water-absorbing region shown in Zone I, the sintering raw materials, particularly iron ore 1, absorb moisture 2, resulting in small particle sizes and small gaps between particles, thus leading to low air permeability during heating. In the granulation region shown in Zone II, moisture 2 that is not completely absorbed by the iron ore 1 appears on the surface of the iron ore, causing the iron ore to adhere to each other, thereby granulation. Therefore, the particle size of the granulated particles increases, the gaps between the particles widen during stacking, and the air permeability during heating improves. In the excess moisture region of Zone III, excess moisture exists in the form of liquid water (water film 3) in the gaps between the granulated particles, which hinders air permeability during stacking. Figure 7 In the example, the granulation limit was reached at a water content of approximately 7.5% by mass. In the region IV, where water was in further excess, the iron ore 1 was in a state of floating in water droplets 4 and became a slurry, resulting in smaller granules and poorer permeability.

[0054] Figure 1 This is a graph showing the effect of adding the reagent used in this embodiment on the relationship between the particle size and moisture content of the granulated particles. Here, Kurisat C333L (registered trademark) manufactured by Kurita Kogyo Co., Ltd. was used as the polymeric coagulant. In reagent addition level 1, the reagent addition amount was set to 0.4% by mass relative to a moisture content of 7.5% by mass. In reagent addition level 2, the reagent addition amount was set to 1.0% by mass relative to a moisture content of 7.5% by mass. The same sintering raw materials were used, except for the addition of the reagent. Regardless of whether the reagent was added, in… Figure 1 Within the specified moisture content range, the blended average particle size of the granulated particles increases with increasing moisture content. However, at a moisture content of 12% by mass, without the addition of the reagent, the excessive water film makes it difficult to form granulated particles, resulting in a significantly smaller blended average particle size compared to the case with the reagent. It can be assumed that in the case with the reagent, the moisture is effectively used for granulation without the formation of a water film.

[0055] Figure 2 This is a graph showing the results of filling the above-mentioned granulated particles into a test firing furnace, adjusting the moisture content, and measuring the air permeability index (JPU). The graph confirms the effect of added chemicals. A higher air permeability index indicates lower air resistance and greater air permeability under the same back pressure. Without added chemicals, the results are compared to... Figure 7 The results were consistent, with a peak at 7.5% moisture content. Regardless of the moisture content, the air permeability index decreased during firing. At 6% moisture content, the air permeability index was lower than in the case without added reagent in both reagent addition level 1 and level 2. On the other hand, in reagent addition level 1, the air permeability index was higher than in the case without added reagent when the moisture content exceeded the granulation limit of 7.5%. In reagent addition level 2, no decrease in air permeability index was observed even at moisture contents exceeding 10% by mass.

[0056] It should be noted that the permeability index is defined as the flow rate of gas passing through a raw material layer of a certain layer thickness per unit area at a location with a pressure gradient of a certain suction negative pressure. Boyce et al. defined the Bed Permeability Unit (BPU) in pounds. Currently, Japan uses the Japan Permeability Unit (JPU) expressed by the following formula (1) and converted to CGS units. The permeability index JPU of the raw material is at a level of 20 to 60, and the permeability index JPU during firing is at a level of 10 to 30.

[0057] Formula (1)

[0058] JPU=(F / A)×(h / s) n

[0059] In the formula, JPU represents the permeability index, F represents the flow rate m 3 / min, A represents the area m 2 , h represents the layer thickness in mm, s represents the negative pressure in mm water column, and n represents the index.

[0060] n is a value that varies in the range of 0.5<n<1.0 depending on the flow state. In the case of iron ore sintering, the average value is n=0.6 in many measurement examples. Since n=1 corresponds to laminar flow and n=0.5 corresponds to turbulent flow, this indicates that the turbulent flow factor of ventilation in the sintered layer is strong.

[0061] Figure 3 is a graph of the results obtained by similarly filling granulated particles into a test firing furnace, determining the firing time based on the temperature change during firing, and investigating the effects of moisture content and added chemicals. The time from the moment when the thermometer directly above the raw material surface of the test apparatus starts to rise in temperature to the moment when the thermometer at the lower part of the apparatus is observed to decrease after the temperature rises is taken as the firing time. It can be seen that when no chemical is added, the firing time is prolonged as the permeability index decreases. It can be seen that by adding the chemical, even if the moisture content increases, the prolongation of the firing time is reduced. Especially when the moisture content exceeds 10%, the firing time of level 2 is shorter than that of level 1.

[0062] Figure 4 is a graph showing the results obtained by calculating the sinter productivity of the actual equipment based on the above firing test results. It can be seen that by adding the chemical, the decrease in sinter productivity caused by excessive moisture can be suppressed. In particular, it can be seen that from the viewpoint of sinter productivity, it is effective to increase the chemical addition amount as the moisture content increases. Figure 5 is a graph showing the relationship between the sinter productivity of the actual equipment and the chemical concentration relative to the moisture content. By increasing the chemical concentration, the productivity at high moisture can be ensured. Figure 6 The relationship between productivity relative to a suitable moisture content of 7.5% and the agent concentration relative to the moisture content is shown. At an unmodified agent concentration of 0%, productivity is only about 10% of the productivity at the suitable moisture content. In contrast, by increasing the agent concentration relative to the moisture content, productivity can be increased to the level of the suitable moisture content.

[0063] Based on the above results, the powder property modification method of this embodiment is as follows: When granulating and heating any one or more water-containing bulk materials selected from ore, coal, and limestone, an agent with any one or more of polymeric coagulants, inorganic coagulants, and polymeric water-absorbing materials as main components is added to the water-containing bulk materials before granulation. At this time, the amount of agent added is adjusted according to the moisture content of the water-containing bulk materials. When the moisture content of the water-containing bulk materials is an excessive amount of moisture that exceeds the granulation limit that would reduce air permeability during heating, it is preferable to increase the amount of active ingredient added of the agent accordingly based on the increase in the excess moisture content. In the above description, the manufacturing method of sintered ore is used as an example of granulating and heating water-containing bulk materials selected from ore, coal, and limestone. In addition to sintered ore, it can also be applied to the manufacturing methods of pellets and coke made from ore, coal, and limestone.

[0064] The following is a detailed explanation of the limiting requirements.

[0065] [A reagent whose main components are selected from one or more of polymeric coagulants, inorganic coagulants, and superabsorbent polymers]

[0066] In this embodiment, a reagent with one or more of the following as its main components is used: a polymeric coagulant, an inorganic coagulant, and a polymeric water-absorbing material. From the viewpoint of reagent addition efficiency and dispersibility, it is preferable to use a diluted solution, a liquid, or a dispersion obtained by diluting the reagent in an aqueous or organic solvent or dispersion medium as the reagent solution (reagent). Here, "aqueous or organic solvent or dispersion medium" refers to a solvent or dispersion medium containing 50% by mass or more of water or an organic compound, such as water containing 1% by mass of a surfactant, or an alcohol (organic compound) containing 30% by mass of water, etc.

[0067] Furthermore, the aforementioned main components utilize the electrostatic forces or hydrogen bonds inherent in polymers to induce adsorption activity in the powder and cause bridging between powder particles. Any main component capable of forming a solidified granular structure and creating agglomerated particles (agglomerates) can be used. For example, powdered, granular, or liquid organic coagulants can be appropriately used. Polyacrylamide-based coagulants (products obtained by copolymerizing acrylamide and sodium acrylate), polyvinyl amidine-based coagulants, and amphoteric polymer coagulants are preferred as they not only exhibit coagulation but also agglomeration effects. It should be noted that known inorganic coagulants (aluminum sulfate, polyaluminum chloride, sodium aluminate, ferric chloride, ferrous sulfate, aluminum sulfate, etc.), organic coagulants, and superabsorbent polymers can also be used in combination.

[0068] In addition, acrylic or acrylamide cationic polymers, methacrylic acid polymers, amino methacrylate cationic polymers, amidine polymers, anionic W / O emulsion polymers, etc. can also be used.

[0069] In this embodiment, "using one or more of the following as the main component" means that the agent contains an amount or more of the following selected from polymeric coagulants, inorganic coagulants, and superabsorbent polymers that is generally considered to have a coagulating effect. As an example, the agent contains approximately 20% by mass or more of the polymeric coagulant. Of course, a substance with 100% of the main component can also be used directly as the agent.

[0070] It should be noted that when the pharmaceutical agent is in solid form or is used in diluted form, the solvent and dispersion medium can be water or organic liquids, and the solute or dispersed phase can be, for example, a polymer composed of C, H, N, and O. Examples of organic liquids include hydrocarbon solvents, i.e., compounds composed of C and H, or C, H, and other elements. Using low-viscosity organic liquids as solvents and dispersion media has the advantage of improving the dispersion of bulk materials.

[0071] [Powder property modification effect]

[0072] The powder property modification method of this embodiment is as follows: When granulating water-containing bulk materials such as ore, coal, and limestone, a given amount of an active ingredient, whose main component is selected from one or more polymeric coagulants, inorganic coagulants, and polymeric water-absorbing materials, is added relative to the mass of the bulk material before granulation. Furthermore, the moisture in the bulk material is retained in the bridging structure formed between the agent and the powder constituting the bulk material, or the form or movement of moisture in the bulk material is controlled. The mechanism by which various problems caused by properties such as adhesion and flowability resulting from moisture sources are solved when granulating water-containing powders can be considered as follows: The agent retains moisture in the gaps between the bulk material, thus preventing free flow; the bulk material layer is polarized into water-filled portions and voids; the powder undergoes secondary particle formation (agglomeration) through moisture and the agent, creating voids not filled with water; and so on. In particular, it is possible to suppress the formation of water films in the gaps between granulated particles, thus preventing impaired air permeability.

[0073] Furthermore, by not only retaining moisture within the bulk material in the aforementioned bridging structure but also converting moisture into compounds or increasing viscosity, retaining moisture in superabsorbent polymers, and using inorganic coagulants to impart charge and cause particle agglomeration, the free flow of moisture can be suppressed, and sometimes the flowability of the powder can also be inhibited. In addition, by using moisture and agents to induce secondary particle formation (agglomeration) in the powder, voids are created, resulting in a so-called "well-drained" state. Some of the moisture flows downwards within the bulk material layer, which can sometimes alleviate various problems caused by properties such as adhesion and flowability resulting from moisture.

[0074] As a method for determining the moisture content of bulk materials, one can use a neutron moisture meter, a resistance moisture meter, a continuous infrared moisture meter, or observation based on image analysis, color, etc.

[0075] The method of adding only a given amount of the active ingredient of the agent relative to the moisture content of the bulk material can be any one or both of the following methods: adjusting the agent addition rate according to the throughput of the bulk material, and adjusting the ratio of agent addition time to non-addition time.

[0076] The active ingredient of the agent refers to a compound, excluding solvents and dispersion media, that has one or more of the following effects: inter-powder bridging, moisture absorption, and particle agglomeration. It is preferable to add the active ingredient of the agent in the range of 0.001 to 0.07% by mass relative to the mass of the bulk material. If added below the lower limit, there is a risk of insufficient moisture retained by inter-powder bridging. On the other hand, even if added above the upper limit, the effect will saturate, and the agent cannot be uniformly dispersed, potentially reducing the uniformity of the water-containing bulk material. It is preferable to add 0.004% or more of the active ingredient of the agent relative to the mass of the bulk material, and more preferably 0.05% or less. Furthermore, from the viewpoint of granulation, it is preferable to add 0.1% or more and 1% or less of the active ingredient of the agent relative to the moisture content of the bulk material.

[0077] It is preferable to mix the bulk materials during or after the addition of the reagent. Existing equipment such as dedicated mixers or crushers can be used for mixing. For example, the reagent can be added on-site and mixed using heavy machinery. Alternatively, the reagent can be placed on the bulk materials on a belt conveyor and mixed by the impact of the falling material in the conveyor's transfer chute. Additionally, mixers, kneaders, and sieves can be used for mixing. These mixing methods improve the diffusion of the reagent relative to the powder, and are expected to enhance the modification effect. It should be noted that, in the case of mixing via belt conveyor transfer, the modification effect on powder properties increases with the number of transfers, up to approximately six times.

[0078] When adding a pharmaceutical agent, if the active ingredient is a solid, it is preferable to disperse or dissolve the active ingredient in water, organic liquids, etc., to form a dispersion or solution. Alternatively, the liquid agent can be diluted before use. By adding liquid to bulk materials, the operability and addition efficiency of the agent can be improved, as well as its dispersibility in the powder constituting the bulk material. When dispersed or dissolved in water, organic liquids, etc., even if the active ingredient of the agent, which was originally a solid, remains in a solid state, or if some or all of it becomes liquid to form a suspension (emulsion), the dispersibility of the agent in the powder constituting the bulk material will be improved.

[0079] Even when the active ingredient of the agent is a liquid, by diluting, dispersing or dissolving the active ingredient in water, organic liquids or the like to make a diluted solution, dispersion or solution, the agent can be added in the form of a solution with a viscosity lower than that of the active ingredient. This can suppress evaporation caused by the vaporization of the active ingredient, thus improving the addition efficiency and the dispersibility of the agent in the powder that constitutes the bulk material.

[0080] Even when the active ingredient of the drug is a gas, by dispersing or dissolving the active ingredient in water, organic liquids, etc., to form a dispersion or solution, the escape of the active ingredient can be suppressed, thus improving the addition efficiency.

[0081] When the concentration of the active ingredient in a pharmaceutical agent during dilution, dispersion, or dissolution in water, organic liquids, etc., is expressed as the ratio of the mass of the active ingredient to the sum of the mass of the active ingredient and the mass of the liquid, this concentration is preferably 5-60% by mass, more preferably 10-45% by mass. By setting the concentration of the active ingredient in the agent above the lower limit, the adverse effects of the liquid itself used for dilution, dissolution, or dispersion, such as fluidization of bulk materials, can be mitigated, thereby improving the efficacy of the agent. By setting the concentration of the active ingredient in the agent below the upper limit, the viscosity of the diluted solution, dispersion, or solution obtained by dilution, dispersion, or dissolution of the active ingredient in water, organic liquids, etc., can be further reduced. As a result, the penetration rate of the agent into the bulk material layer is further increased, and the non-uniformity of the agent is further reduced.

[0082] Furthermore, in this embodiment, it is preferable to add an aqueous or organic liquid different from the pharmaceutical agent when adding the agent to the bulk material or during stirring. This improves the dispersibility of the active ingredient of the agent in the powder constituting the bulk material.

[0083] Industrial applicability

[0084] According to the powder property modification method and sinter manufacturing method of the present invention, when granulating and heating hydrated bulk materials, a coagulant and a water-absorbing material are added accordingly based on the moisture content of the bulk material. Therefore, the decrease in air permeability during heating caused by excessive moisture can be suppressed. This shortens the heating time and improves productivity, making it industrially useful. Furthermore, the powder property modification method of the present invention can be used to manufacture granules such as sinter, reduced iron, and pellets.

Claims

1. A method for modifying the properties of powder, the method comprising: When granulating and heating bulk materials containing moisture... Before granulation or during the granulation process, an agent with one or more of the following as the main components is added to the water-containing bulk material. At this time, the amount of the agent added is adjusted according to the moisture content of the water-containing bulk material or the operating indicators related to the moisture content of the water-containing bulk material.

2. The powder property modification method according to claim 1, wherein, The water-containing bulk material is at least one of the following: ore, slag (a byproduct of ore refining or steel manufacturing), and byproduct of petroleum distillation / rectification.

3. A method for manufacturing sintered ore, comprising granulating and heating sintered ore containing iron-containing raw materials, carbon-containing raw materials, and CaO-containing raw materials as water-containing bulk materials, the method comprising: In the powder property modification process, according to the powder property modification method of claim 1 or 2, the amount of the agent added is adjusted accordingly based on the moisture content of the raw material for sintering or the operating index related to the moisture content of the water-containing bulk material. In the granulation process, a granulator is used to granulate the modified sintering raw materials. as well as In the sintering process, the granulated raw materials for sintering are sintered using a sintering machine.

4. The method for manufacturing sintered ore according to claim 3, wherein, The amount of reagent added in the powder property modification process is adjusted accordingly based on the air permeability index in the sintering process or the operating condition index related to air permeability.

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