Method for modifying powder properties, method for producing water-containing bulk material, water-containing bulk material, and method for granulating raw material for sintering

Abstract

The invention provides a method for solving various problems caused by moisture when powder containing moisture is processed. Provided is a powder property modification method in which, when treating a water-containing bulk material such as ore, coal, and limestone, an active ingredient of a reagent containing, as a main component, at least one substance selected from the group consisting of polymeric flocculants, inorganic flocculants, and polymeric absorbent materials is added in a range of 0.001-0.07 mass% with respect to the mass of the bulk material, and the active ingredient of the reagent containing, as a main component, at least one substance selected from the group consisting of the polymeric flocculants, inorganic flocculants, and polymeric absorbent materials. The moisture in the bulk material is maintained in a cross-linked structure formed between the reagent and the powder constituting the bulk material. A method for manufacturing a water-containing bulk material which is transported by at least one member selected from the group consisting of a ship, a transport vehicle, a loading heavy-duty machine, an unloading heavy-duty machine, a belt conveyor, and a storage tank, said method being characterized in that the water-containing bulk material is modified by the modification method.

Description

Technical Field

[0001] The present invention relates to a method for modifying the properties of a water-containing powder developed to eliminate the hindrance caused by water generated when handling water-containing bulk materials such as ore, coal and limestone. In addition, it relates to a method for producing a water-containing bulk material using the modification method and a method for granulating the water-containing bulk material and a raw material for sintering using the water-containing bulk material. Background Art

[0002] For bulk materials such as powders, such as ore and coal, if the moisture content increases during mining and transportation, failures caused by adhesion to equipment and ore falling often occur. When the moisture content increases further, the bulk material becomes muddy, which not only cannot be handled, but also sometimes causes equipment damage due to spraying at the transfer point and collapse of the stockpile. In addition, most of these bulk materials are transported by sea to all parts of the world. Due to the liquefaction phenomenon during marine transportation, the transport ship capsizes due to the destruction of the hull balance, failures in loading and unloading operations at the unloading port side, and equipment damage may occur.

[0003] In addition, the frequency of these failures will increase further due to repeated rainfall during operations, which will cause the bulk material to have high moisture content, and the impact of the failures that occur will become greater.

[0004] To solve this problem, methods such as those disclosed in Patent Documents 1 and 2 have been used in the past. Specifically, methods that emphasize water removal, such as a method of first sucking up the water with drainage equipment (suction machine) when water surge occurs and then restarting unloading, have been proposed.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 60-204526

[0008] Patent Document 2: Japanese Utility Model Publication No. 50-13339

[0009] Patent Document 3: Japanese Patent Application Laid-Open No. 61-60784

[0010] Patent Document 4: Japanese Patent Application Laid-Open No. 61-164658 Summary of the invention

[0011] Problems to be solved by the invention

[0012] However, the above-mentioned prior art has the following problems.

[0013] That is, for the pumping drainage methods proposed in Patent Documents 1 and 2, in order to draw water, the ship needs to be moved to the place where the drainage, that is, the pumping equipment is located each time. Or, the drainage equipment itself needs to be moved to draw water from the cabin, etc. Therefore, there is a problem that the operation time becomes longer.

[0014] In particular, the gushing water is often generated in the pits formed after the grab bucket is used to grab the water during the unloading process. Therefore, the above-mentioned pumping out drainage method requires repeated operation of pumping out the gushing water. Therefore, due to repeated interruption and restart of the unloading operation, there is a problem of greatly reduced operation efficiency.

[0015] In recent years, especially, as existing mines have been gradually closed due to the exhaustion of ore and coal resources, the proportion of inferior ore and coal, such as ore and coal with high moisture content, has increased. Therefore, this problem has become more prominent.

[0016] In addition, when the moisture content of the unloaded ore or coal is high, the bulk material becomes easy to flow before the water surge occurs. Therefore, it causes obstacles to the transportation using the belt conveyor during unloading. In addition to transportation failures, maintenance problems of belt conveyor equipment often occur.

[0017] In addition, the prior art proposed in Patent Documents 1 and 2 assumes that only gushing water is sucked out. However, in the pit portion generated after grabbing with a grab bucket, powder with a small particle size separated from bulk materials with a large particle size flows in, and most of them become muddy, that is, slurry. In the case of sucking out such a muddy fluid, it is difficult to suck out using existing drainage equipment, and the operating efficiency is further reduced each time a gushing water occurs. In the case of direct unloading, as mentioned above, the bulk materials after unloading are highly fluid, so they sometimes flow out from the belt conveyor or spray out at the transition part. As a result, unloading obstacles occur.

[0018] In addition to the examples described above, when handling powders containing water, various problems may arise during loading and unloading, storage, transportation, use, that is, when the powder is put into equipment and during handling due to the adhesion, fluidity and other characteristics caused by the water. As a problem arising during use, for example, in the process of adding water to the powder for granulation, when water is excessively exposed on the surface of the granulated material in the middle of the granulation, the small-particle powder that is easily aggregated due to the surface tension of the water sometimes preferentially adheres and granulates. In this way, sometimes coarse and low-strength granules mainly composed of small-particle powders are produced. In addition, in the stage before the process of adding water to the powder for granulation, the small-particle powder has already solidified due to the influence of water, that is, naturally granulated, and sometimes coarse and low-strength granules mainly composed of small-particle powders are produced.

[0019] In addition, the particle size of powders that become problematic due to moisture is usually 3 mm or less. However, even if the bulk material has a maximum particle size of more than 3 mm, if it contains particles with a particle size of less than 3 mm or has particles with a particle size of less than 3 mm due to impact during transportation, the adhesion and fluidity caused by moisture may become problematic. Powders with a particle size of less than 3 mm and bulk materials containing more than 10% by mass of powders with a particle size of less than 3 mm are problematic for adhesion and fluidity caused by moisture.

[0020] In view of these problems, the inventors have focused on the methods for reducing the water content proposed in Patent Documents 3 and 4 and have repeatedly conducted research. However, in the methods described in Patent Documents 3 and 4, since a solid water-absorbent resin is used, there is a problem that it is difficult to uniformly contact the bulk material during unloading. In addition, it is known that since the water-absorbent resin swells when it contains water, the swollen water-absorbent resin or the bulk material containing the water-absorbent resin itself may fail during handling. In addition, it takes tens of seconds to tens of minutes for the water-absorbent resin to exert its effect after contacting with water as an object, so it is extremely difficult to obtain the desired effect without reducing productivity in existing equipment.

[0021] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a technology for solving various problems caused by the properties such as adhesion and fluidity caused by the water when handling powder containing water.

[0022] Methods used to solve problems

[0023] The method for modifying the properties of a powder of the present invention, which advantageously solves the above-mentioned problems, is characterized in that, when treating a water-containing bulk material such as ore, coal and limestone, an effective ingredient of a reagent having one or more selected from a polymer flocculant, an inorganic flocculant and a polymer water-absorbing material as a main component is added in a range of 0.001 to 0.07 mass % relative to the mass of the bulk material, and optionally, when or after the reagent is added to the bulk material, the bulk material is stirred and mixed, and the reagent is diffused in the powder by stirring using existing equipment such as a dedicated mixer or crusher, stirring using heavy machinery, or stirring using the impact at the transfer drop of a conveyor belt conveyor, so that the moisture in the bulk material is maintained in the cross-linked structure formed between the reagent and the powder constituting the bulk material, or the form or movement of the moisture in the bulk material is controlled by the cross-linked structure formed between the reagent and the powder constituting the bulk material.

[0024] It should be noted that, for the powder property modification method of the present invention, the following means are more preferred solutions:

[0025] (a) diluting, dispersing or dissolving the active ingredient in an aqueous or organic liquid to prepare a reagent, and adding the reagent to the bulk material as the object, and optionally adding an aqueous or organic liquid separately from the reagent when adding the reagent or during the stirring;

[0026] (b) determining the required amount of the active ingredient to be added based on the mass of the bulk material and the moisture content of the bulk material, and adjusting the amount of the reagent to be added in a manner that satisfies the required amount;

[0027] (c) in the reagent, the ratio of the active ingredient to the sum of the active ingredient and the liquid is 5 to 60% by mass;

[0028] (d) In the reagent, a ratio of the active ingredient to the sum of the active ingredient and the liquid is 10 to 45% by mass.

[0029] The method for producing a hydrated bulk material of the present invention, which advantageously solves the above-mentioned problems, is a method for producing a hydrated bulk material that is transported by any one or more selected from a ship, a transport vehicle, a loading heavy machinery, an unloading heavy machinery, a belt conveyor and a storage tank, and is characterized in that the hydrated bulk material is modified by any one of the above-mentioned modification methods.

[0030] The water-containing bulk material of the present invention which advantageously solves the above-mentioned problems is a water-containing bulk material transported by at least one selected from a ship, a transport vehicle, a loading heavy machine, an unloading heavy machine, a belt conveyor and a storage tank, and is characterized in that it is modified by any of the above-mentioned modification methods. The granulation method of the raw material for sintering of the present invention is characterized in that the above-mentioned water-containing bulk material is used as a part or all of the raw material.

[0031] Effects of the Invention

[0032] The powder property modification method according to the present invention has the following effects in mines, harbors, stockpiles, ship transportation, and unloading ports. It is applied when the moisture value of bulk materials such as ore, coal, and limestone increases, that is, when processing water-containing powders that constitute water-containing bulk materials. In this way, problems such as equipment stoppage caused by adhesion, ejection during transportation, backflow, and collapse of storage piles will not occur. Therefore, there is no need to interrupt the operation as in the past, and continuous operation can be carried out. Therefore, the productivity in each process is improved, so it is useful in industry. If stirring and mixing are implemented when adding the reagent to the bulk or after adding the reagent, the diffusion of the reagent in the powder can be achieved, and the modification effect of the powder properties is further improved, so it is preferred. If the reagent is made into an aqueous or organic diluent, dispersion, or solution, the handleability of the reagent is improved. Moreover, when the reagent is added to the bulk and stirred, the diffusibility of the reagent in the powder is improved, so it is preferred. It is preferred to add an aqueous or organic liquid separately when adding the reagent or stirring the bulk material because the dispersibility of the reagent is improved.

[0033] In the method for producing a hydrated bulk material and the hydrated bulk material of the present invention, the above-mentioned modification method is applied to the hydrated bulk material transported by ships, transport vehicles, loading heavy machinery, unloading heavy machinery, belt conveyors, storage tanks, etc. In this way, the hydrated bulk material is modified, and problems in storage and transportation are reduced, which is preferred.

[0034] The granulation method of the raw material for sintering of the present invention can suppress the direct solidification of small-particle powder of a water-containing bulk material in a non-uniform state, so that the strength of the granulated material is not reduced, the yield during sintering, the uniformity of the mineral structure, the productivity, etc. are improved, and it is industrially useful. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 This is a graph showing the relationship between the reagent concentration and FMP relative to the water content of the bulk material.

[0036] Figure 2 This is a graph showing the relationship between the reagent concentration and the unit consumption of the ore drop relative to the water content of the bulk material.

[0037] Figure 3 This is a graph showing the relationship between the reagent concentration (mass percentage) relative to the water content of the bulk material, the number of failures related to belt conveyor transportation, and the failure processing time.

[0038] Figure 4 This is a graph showing the relationship between the concentration of the active ingredient in the reagent and FMP.

[0039] Figure 5 This is a diagram showing an example of the concentration of the added reagent according to the water content of the bulk material.

[0040] Figure 6 The figures show the influence of whether or not a reagent is added to the bulk material on various sintering parameters of the sintering raw material, (a) shows air permeability, (b) shows sintering time, (c) shows yield, and (d) shows finished product productivity. DETAILED DESCRIPTION

[0041] The following is a detailed description of the embodiments of the present invention. In addition, the following embodiments illustrate the method for implementing the technical concept of the present invention, and do not limit the composition to the following content. That is, the technical concept of the present invention can be variously modified within the technical scope described in the claims.

[0042] [Agent containing at least one selected from a polymer flocculant, an inorganic flocculant and a polymer water-absorbing material as a main component]

[0043] In the present embodiment, a reagent having any one or more selected from a polymer flocculant, an inorganic flocculant and a polymer water-absorbing material as a main component is used. From the viewpoint of the addition efficiency and dispersibility of the reagent, it is preferred to use a diluent, a solution or a dispersion obtained by diluting, dissolving or dispersing the reagent in an aqueous or organic solvent or dispersion medium as a liquid medicine (reagent). Here, the "aqueous or organic" solvent or dispersion medium is respectively a "solvent or dispersion medium containing more than 50% by mass of water or an organic compound", for example, water containing 1% by mass of a surfactant, alcohol (organic compound) containing 30% by mass of water, etc.

[0044] In addition, the above-mentioned main component uses a substance that produces adsorption activity on the powder through the electrostatic force or hydrogen bond possessed by the polymer and plays a cross-linking effect between the powders. As long as the main component has the effect of forming a solid granulated structure to form condensed particles (aggregates), it can be used. For example, powder, granular or liquid organic flocculants can be used appropriately. Polyacrylamide (a substance obtained by copolymerizing acrylamide and sodium acrylate), polyethylene amidine, amphoteric polymer flocculants, etc. not only play a coagulation effect, but also play a flocculation effect, so they are preferred. It should be noted that known inorganic flocculants (aluminum sulfate, polyaluminum chloride, sodium aluminate, ferric chloride, ferrous sulfate, aluminum sulfate, etc.), organic flocculants, and polymer water-absorbing materials can be further used in combination.

[0045] Also usable are acrylic acid-based or acrylamide-based cationic polymers, methacrylic acid-based polymers, methacrylic acid amino ester cationic polymers, amidine polymers, anionic W / O type emulsion polymers, and the like.

[0046] In this embodiment, the main component is selected from any one or more of a polymer flocculant, an inorganic flocculant, and a polymer water-absorbing material. Generally, it means that the reagent contains more than an amount considered to have a flocculation effect, and is selected from any one or more of a polymer flocculant, an inorganic flocculant, and a polymer water-absorbing material. As an example, it is a reagent with a polymer flocculant content of about 20% by mass or more. Of course, a substance with a main component of 100% can also be directly used as a reagent.

[0047] It should be noted that, when the reagent is solid or diluted for use, water and organic liquids can be cited as solvents and dispersion media, and polymers containing C, H, N, and O can be cited as solutes and dispersions. As organic liquids, hydrocarbon solvents, i.e., compounds composed of C and H, or C, H and other elements, can be cited. When low-viscosity organic liquids are used as solvents and dispersion media, there is an advantage that dispersion into bulk materials is improved.

[0048] [Powder property modification method]

[0049] In the powder property modification method of the present embodiment, when processing water-containing bulk materials such as ore, coal and limestone, only the effective component of a reagent with one or more selected from polymer flocculants, inorganic flocculants and polymer water-absorbing materials as the main component is added in a specified amount relative to the mass of the bulk. In addition, the moisture in the bulk is maintained in the cross-linked structure formed between the reagent and the powder constituting the bulk, or the form or movement of the moisture in the bulk is controlled by the cross-linked structure formed between the reagent and the powder constituting the bulk. It is believed that the mechanism for solving various problems caused by the adhesion, fluidity and other characteristics generated by moisture when processing powders containing moisture is as follows. Since the moisture is maintained in the gaps of the bulk by the reagent, the moisture does not flow freely, and the bulk layer is polarized into parts filled with water and voids, and the powder is secondary particle-formed (agglomerated) due to the moisture and the reagent, thereby generating voids that are not filled with water.

[0050] In addition to retaining the water in the bulk in the cross-linked structure, the free flow of water can be inhibited and the fluidity of the powder can be inhibited by converting the water into compounds or increasing the viscosity, retaining the water in the polymer absorbent, and aggregating the particles due to the charge given by the inorganic flocculant. In addition, since the powder is secondary particles (agglomerated) by the water and the reagent, and voids are generated, it becomes a so-called "well-drained" state, and part of the water flows into the layer of the bulk, which sometimes alleviates various problems caused by the characteristics such as adhesion and fluidity caused by the water.

[0051] The amount of the active ingredient of the reagent added relative to the amount of the bulk material can be determined according to the brand of the bulk material. It is further preferred that if the moisture content of the bulk material is measured and determined based on the measured moisture content of the bulk material, the effect of the reagent can be enjoyed while reducing the amount of reagent used. This is particularly effective when the moisture content of the bulk material varies.

[0052] As a method for measuring the mass of bulk materials, the following methods can be cited. First, there is the linemetric method, that is, a method of measuring the passing mass of the transported object based on the speed and load of the belt conveyor. In addition, there is also a method of calculating the passing mass based on the object volume estimation performed by a TOF (time of flight: non-contact distance meter) sensor, that is, measuring the passing volume of the transported object based on the speed of the belt conveyor and the stacking height on the belt conveyor and multiplying it by the stacking density. This non-contact distance meter can measure the height of the transported object on the conveyor. It is also possible to use the driving current value of the belt conveyor, the observation of the shape based on image analysis, etc.

[0053] As a method for measuring the moisture content of bulk materials, a "neutron moisture meter", "electrical resistance moisture meter", "continuous infrared moisture meter", "observation of color etc. by image analysis" can be used.

[0054] Regarding the method of adding only the active ingredient of the reagent in a predetermined amount relative to the mass of the bulk material, either or both of a method of adjusting the reagent addition rate according to the passing speed of the bulk material and a method of adjusting the ratio of the reagent addition time to the non-addition time can be used.

[0055] The active ingredient of the reagent refers to a compound other than the solvent and the dispersion medium that has any one or more of the cross-linking effect between powders, the water absorption effect and the particle flocculation effect. The active ingredient of the reagent is added in the range of 0.001 to 0.07 mass % relative to the mass of the bulk. When the addition is below the lower limit, the amount of water retained by the cross-linking between powders may be insufficient. Excess water may cause problems such as equipment stoppage caused by the adhesion of powders, spraying, backflow during the transportation of powders, and collapse of the storage pile. On the other hand, even if it is added in excess of the upper limit, the effect will be saturated, and the reagent cannot be evenly dispersed, and the uniformity of the water-containing bulk may be reduced. It is preferred to add more than 0.004 mass % of the active ingredient of the reagent relative to the mass of the bulk, and it is preferred to add less than 0.05 mass % of the active ingredient of the reagent.

[0056] It is preferred that the bulk material is stirred and mixed when or after the reagent is added. Existing equipment such as a dedicated mixer or crusher can be used for stirring and mixing. For example, the reagent can be added to the yard and stirred and mixed using heavy machinery. The reagent can also be added to the bulk material on the conveyor belt conveyor and mixed by the drop impact at the transfer chute of the conveyor belt conveyor. In addition, a mixer, a kneading machine, a screen, etc. can also be used for stirring and mixing. Through these stirring and mixing, it is expected to improve the diffusibility of the reagent in the powder and improve the modification effect. It should be noted that at this time, in the stirring and mixing performed by the transfer of the conveyor belt conveyor, within the range of at least 1 transfer to about 6 transfers, as the number of transfers increases, the modification effect of the powder properties increases.

[0057] When adding reagents, when the active ingredient of the reagent is solid (solid substance), it is preferred to disperse or dissolve the active ingredient of the reagent in water, organic liquid, etc. to form a dispersion or solution. The liquid reagent can also be diluted for use. By adding liquid to the bulk, the handling property and addition efficiency of the reagent can be improved, and the dispersibility of the reagent in the powder constituting the bulk is improved. When dispersed or dissolved in water, organic liquid, etc., whether the active ingredient of the reagent as a solid substance remains in a solid state, or a part or all of it becomes liquid and becomes a suspension (emulsion), the dispersibility of the reagent in the powder constituting the bulk is improved.

[0058] Even in the case where the active ingredient of the reagent is a liquid, it is possible to prepare a diluent, a dispersion or a solution by diluting, dispersing or dissolving the active ingredient of the reagent in water, an organic liquid or the like. By adding the reagent in the form of a solution having a viscosity lower than that of the active ingredient of the reagent, evaporation caused by the vaporization of the active ingredient of the reagent can be suppressed, thereby achieving an improvement in the addition efficiency and improving the dispersibility of the reagent in the powder constituting the bulk material.

[0059] Even when the active ingredient of the reagent is a gas, the active ingredient of the reagent can be dispersed or dissolved in water, an organic liquid, etc. to prepare a dispersion or a solution, thereby suppressing the loss of the active ingredient of the reagent, thereby achieving improved addition efficiency.

[0060] When the concentration of the active ingredient of the reagent is diluted, dispersed or dissolved in water, an organic liquid, etc., as expressed by the ratio of the active ingredient mass to the sum of the active ingredient mass and the liquid mass, the concentration is preferably 5 to 60% by mass, and more preferably 10 to 45% by mass. By setting the active ingredient concentration in the reagent to above the lower limit, the effect of the reagent is improved by reducing the disadvantages of the fluidization of the bulk material caused by the liquid itself used for dilution, dissolution or dispersion of the reagent. By setting the active ingredient concentration in the reagent to below the upper limit, the viscosity of the dilution, dispersion or solution obtained by diluting, dispersing or dissolving the active ingredient of the reagent in water, an organic liquid, etc. is further reduced. Due to this effect, the penetration rate of the reagent into the layer of the bulk material is further improved, and the uneven presence of the reagent is further reduced.

[0061] In addition, in the present embodiment, it is preferred that an aqueous or organic liquid is added separately from the reagent when the reagent is added to the bulk material or when the reagent is stirred. The dispersibility of the active ingredient of the reagent in the powder constituting the bulk material is improved.

[0062] By applying the powder property modification method of the present embodiment, the following effects can be expected when handling water-containing bulk materials such as ore, coal, and limestone. Since the adhesion of powder to equipment and devices, spraying and backflow during transportation, etc. are suppressed, the handleability of the bulk material is improved. Since the water content is controlled by the cross-linked structure of the reagent and the powder, and the specific surface area or air permeability of the bulk material is increased, the dryness of the bulk material is improved. By fixing the water content, the liquefaction of the bulk material can be suppressed. In addition, the collapse of the piled material stockpile can be suppressed. The influence of flooding by rainwater, etc. can be suppressed. The freezing of the stockpile can be suppressed.

[0063] Example

[0064] (Example 1)

[0065] The reagent of the above embodiment was added to the carajás powder ore, and the change of FMP (Flow Moisture Point) was confirmed. FMP is also called the flow moisture value, which is a value measured by the method specified by the BC CODE (Code of Safe Practice for Solid Bulk Cargoes) of the International Maritime Organization (IMO). FMP is represented by the moisture content (mass percentage) at which fluidity begins to be shown. When loading bulk materials onto ships, there is a danger of capsizing of the ship when the bulk materials show fluidity, so loading onto the ship is implemented at a moisture content lower than FMP (generally less than 90% of FMP). The disadvantages caused by the bulk materials showing fluidity occur not only on ships, but also in the form of flow on belt conveyors, transport vehicles, loading heavy machinery, unloading heavy machinery, etc., and outflow from storage tanks.

[0066] exist Figure 1 The relationship between the reagent concentration (mass percentage) and FMP relative to the water content of the bulk is shown in . From the results, it can be seen that when the water content of the bulk exceeds 9.90% by mass without adding the reagent (○ mark), fluidity is shown. On the other hand, it can be seen that when the reagent concentration relative to the water content of the bulk is within an appropriate range (● mark), when the reagent concentration is increased, the FMP also increases together, and the fluidity of the bulk can be suppressed even if the water content of the bulk increases compared to before the addition of the reagent. On the other hand, it can be seen that when the reagent concentration relative to the water content of the bulk is 0.72% by mass (▲ mark), the effect reaches the upper limit. Therefore, by setting the reagent concentration relative to the water content of the bulk to 0.01-0.45% by mass, that is, setting the reagent concentration relative to the mass of the water-containing bulk to 0.001-0.07% by mass, the water content (FMP) at which the bulk begins to show fluidity can be effectively increased. Therefore, it is possible to reduce adverse conditions such as flow in belt conveyors and storage tanks, represented by the capsizing of ships.

[0067] (Example 2)

[0068] When transporting bulk materials by belt conveyor, reagents were added to investigate the effect of reducing ore drops and transport failures caused by adhesion. Here, ore drops mainly refer to ore drops after the folding position instead of the folding position of the conveyor due to adhesion to the conveyor belt. Bulk materials with a water content of 8 to 8.5% by mass and a particle size of 0.125 mm or less with a weight ratio of 17 to 19% by mass were taken as the objects for totalization.

[0069] exist Figure 2The relationship between the reagent concentration (mass percentage) relative to the water content of the bulk material and the unit consumption of the ore (kg / (t·m)) is shown in FIG. Here, the unit consumption of the ore is expressed as the ratio of the mass (kg) of the bulk material lost during the belt conveyor transportation to the total transport mass (t) and the transport distance (m). Figure 3 The relationship between the reagent concentration (mass percentage) relative to the bulk moisture content and the number of failures and failure processing time related to belt conveyor transportation is shown in FIG. Figure 3 In the bar graph showing the failure occurrence frequency on the left axis, A represents the frequency of the belt conveyor tilting, B represents the frequency of unplanned cleaning due to attachment, and C represents the frequency of other causes. Figure 3 The line in the middle represents the fault handling time on the right axis. Figure 2 The results clearly show that when the reagent concentration relative to the bulk water content is 0.1 mass %, the ore drop is reduced by 55%, and when the reagent concentration relative to the bulk water content is 0.5 mass %, the ore drop is reduced by 84%. Figure 3 The results clearly show that when the reagent concentration relative to the water content of the bulk material is 0.1-0.5 mass %, the frequency of failures related to belt conveyor transportation is roughly halved, and the failure processing time is reduced to less than 1 / 3. In particular, the failures that are reduced are the tilting of the belt conveyor (A) and unplanned cleaning caused by attachments (B). In addition, in the case of more than 40 mm of rainfall during storage in the stockyard of open-air bulk materials and transportation by belt conveyors, when no reagent is added (0 mass %), ejection from the storage hopper caused by fluidization in the storage hopper occurs repeatedly. On the other hand, when the reagent concentration relative to the water content of the bulk material is set to 0.1 mass % to 0.5 mass %, ejection from the storage hopper will not occur even if there is 80 mm of rainfall.

[0070] In addition, when the reagent concentration relative to the water content of the bulk material is set to 0.1 to 0.5% by mass, when other bulk materials are mixed in the bulk material, the bulk materials will not be unevenly distributed but will be evenly dispersed, so the quality of the mixed bulk material is improved. For example, when the reagent is added to the sintering raw material, the uniformity of the sintered ore is increased, the strength deficiency of the uneven part that has been generated in the past is reduced, and the powdering is reduced, thereby improving the yield rate. In addition, when the reagent concentration relative to the water content of the bulk material is set to 0.1 to 0.5% by mass, there is also an effect that the bulk material does not agglomerate but is evenly dispersed. For example, the efficiency is improved in the drying of coal.

[0071] (Example 3)

[0072] In Examples 1 and 2, the reagent is added on the belt conveyor that transports the bulk. In contrast, when a mixer is used for the purpose of improving the mixing of the reagent into the bulk, the same effect can be obtained even if the amount of reagent added is reduced to 9 / 10. For bulk brands that are difficult to use a mixer, the same effect can be obtained by adding the reagent at the transition section of the belt conveyor or just before the transition section, even if the amount of reagent added is reduced to 19 / 20.

[0073] (Example 4)

[0074] Under the same conditions as in Example 1, a reagent is added to the carajas powder ore. At this time, as the form of the reagent, a substance obtained by dissolving a solid active ingredient of the reagent in water is used, and the ratio of the mass of the active ingredient to the sum of the mass of the active ingredient and the mass of the water used for the dissolution, that is, the concentration of the active ingredient in the reagent is changed. The reagent is continuously added on the belt conveyor, and samples are taken from the top, middle and bottom of the pile of carajas powder ore to which the reagent has been added, which falls from the terminal of the belt conveyor. The FMP of the sample is measured, and the lowest FMP value among the three places is taken as the lowest FMP value. Figure 4 The relationship between the concentration of the active ingredient in the reagent and the minimum value of FMP is shown in FIG. Figure 4 It can be seen that when the concentration of the active ingredient in the reagent is in the range of 5 to 60 mass %, the minimum FMP value is higher, and the local decrease in the FMP increase effect caused by the uneven presence of the reagent is suppressed. This tendency is more significant when the concentration of the active ingredient in the reagent is in the range of 10 to 45 mass %.

[0075] (Example 5)

[0076] Due to the influence of weather and other factors, the moisture content of the bulk material may deviate from the range of 8 to 8.5% by mass. The moisture content of the bulk material is measured under the same conditions as in Example 2 except for the moisture content of the bulk material, and the amount of reagent added is adjusted. The moisture content of the bulk material is measured by collecting the bulk material in advance at the storage yard. When it is predicted that the moisture content of the bulk material may fluctuate in a short period of time due to rainfall during transportation on a belt conveyor, an infrared moisture meter installed on the belt conveyor is used to continuously measure the moisture content. When adjusting the amount of reagent added according to the measured moisture content of the bulk material, such as Figure 5As shown in the figure, the reagent concentration relative to the bulk moisture content (bulk mass × bulk moisture content) is set, and the reagent addition rate is adjusted. At this time, when the bulk moisture content is low, for example, 5% by mass, and the reagent addition rate is small, the reagent addition rate can be adjusted by repeatedly adding the reagent intermittently, for example, adding for 2 seconds and then stopping for 1 second. By more accurately grasping the bulk moisture content in this way and adjusting the reagent addition amount accordingly, even if the reagent concentration relative to the bulk moisture content is reduced to 9 / 10 of that in Example 2, the same effect can be obtained.

[0077] (Example 6)

[0078] In an ironworks, the following process is used: lime, carbon material and water are added to powder ore stored in a raw material yard to granulate, and then sintered in a sintering furnace to produce sintered ore, which is used as a blast furnace raw material. At this time, a comparison was made between the case where a reagent was added during bulk transportation and the case where a reagent was not added. In the case where a reagent was added, 0.3% by mass of the reagent was added to the powder ore before being stored in the raw material yard relative to the water content contained in the powder ore.

[0079] The results of the sintering process are shown in Figure 6 middle. Figure 6 (c) is the yield of sintered ore. The yield is the ratio of the ore above the sieve when the ore is crushed into particles of about 20 mm in diameter after being fired in a sintering furnace and sieved through a sieve with a mesh of 10 mm. The undersize material that passes through the sieve with a mesh of 10 mm does not meet the standards and cannot become a finished product because it hinders the air permeability in the blast furnace when loaded into the blast furnace. From this result, it can be seen that when the reagent is added, the undersize material that passes through the sieve with a mesh of 10 mm decreases. It is believed that this is because, with respect to the powder ore stored in the raw material yard, the solidification (natural granulation) of the small-particle powder is suppressed due to the influence of moisture. That is, it is believed that this is due to the reduction in the production of coarse and low-strength granules mainly composed of small-particle powder. Figure 6 (a) is the air permeability after granulation. It is known that the air permeability is improved by adding the reagent. It is believed that the deterioration of the air permeability caused by the destruction of the low-strength granulated material before sintering in the sintering furnace is reduced. Since the air permeability affects the sintering time in the sintering furnace, Figure 6 As shown in (b), the firing time was shortened by about 20% by adding the reagent. Figure 6 (d) shows the product productivity. The product productivity increased by more than 20% due to the synergistic effect of the increase in the yield due to the addition of the reagent and the shortening of the firing time.

[0080] Industrial Applicability

[0081] According to the method for modifying powder properties, the method for producing a water-containing bulk material, and the water-containing bulk material of the present invention, since the handling properties of the water-containing bulk material during transportation and storage and the stability of the stockpile are improved, the bulk material can be effectively utilized and accidents can be prevented before they occur, which is useful in industry. In addition, according to the method for granulating a raw material for sintering of the present invention, the yield rate is improved, the sintering time is shortened, and the productivity is improved, which is useful in industry.

Claims

1. A method for modifying powder properties, wherein: When handling water-containing bulk materials such as ore, coal and limestone, An effective ingredient of a reagent having at least one selected from a polymer flocculant, an inorganic flocculant and a polymer water-absorbing material as a main component is added in a range of 0.001 to 0.07 mass % relative to the mass of the bulk material, Optionally, when or after the reagent is added to the bulk, the bulk is stirred and mixed, and the reagent is diffused in the powder by stirring using existing equipment such as a dedicated mixer or crusher, stirring using heavy machinery, or stirring using the impact of a transfer drop of a conveyor belt conveyor. The moisture in the bulk material is retained in a cross-linked structure formed between the reagent and the powder constituting the bulk material.

2. A method for modifying powder properties, wherein: When handling water-containing bulk materials such as ore, coal and limestone, An effective ingredient of a reagent having at least one selected from a polymer flocculant, an inorganic flocculant and a polymer water-absorbing material as a main component is added in a range of 0.001 to 0.07 mass % relative to the mass of the bulk material, Optionally, when or after the reagent is added to the bulk, the bulk is stirred and mixed, and the reagent is diffused in the powder by stirring using existing equipment such as a dedicated mixer or crusher, stirring using heavy machinery, or stirring using the impact of a transfer drop of a conveyor belt conveyor. The form or movement of water in the bulk material is controlled by the cross-linked structure formed between the reagent and the powder constituting the bulk material.

3. The method for modifying powder properties according to claim 1 or 2, wherein: The active ingredient is diluted, dispersed or dissolved in an aqueous or organic liquid to prepare a reagent, and the reagent is added to the target bulk. Optionally, an aqueous or organic liquid is added separately from the reagent during the addition of the reagent or during the stirring.

4. The method for modifying powder properties according to claim 3, wherein: The required amount of the active ingredient to be added is determined according to the mass of the bulk material and the moisture content of the bulk material, and the amount of the reagent to be added is adjusted in a manner to meet the required amount.

5. The method for modifying powder properties according to claim 3, wherein: In the reagent, a ratio of the active ingredient to the sum of the active ingredient and the liquid is 5 to 60% by mass.

6. The method for modifying powder properties according to claim 3, wherein: In the reagent, a ratio of the active ingredient to the sum of the active ingredient and the liquid is 10 to 45% by mass.

7. A method for producing a water-containing bulk material, which is a method for producing a water-containing bulk material that is transported by at least one selected from a ship, a transport vehicle, a loading heavy machine, an unloading heavy machine, a belt conveyor, and a storage tank, wherein: The water-containing bulk material is modified by the modification method according to any one of claims 1 to 6.

8. A water-containing bulk material transported by any one or more selected from a ship, a transport vehicle, a loading heavy machine, an unloading heavy machine, a belt conveyor and a storage tank, wherein: The aqueous bulk material is an aqueous bulk material modified by the modification method according to any one of claims 1 to 6.

9. A method for granulating a raw material for sintering, wherein: The water-containing bulk material according to claim 8 is used as a part or all of the raw material.

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