Method for preventing adhesion and clogging of mineral raw material

Abstract

To provide a method for preventing adhesion and clogging of a mineral raw material, which exhibits an excellent modification effect (reduction in adhesion) even when an excessive amount of a w / o emulsion polymer is brought into contact with the mineral raw material.SOLUTION: A method for preventing adhesion and clogging of a mineral-derived material in a transporting and processing facility, the method comprising: transporting and / or processing a material mixture in the transporting and processing facility, the material mixture being obtained by contacting the mineral-derived material with a W / O emulsion polymer, wherein the W / O emulsion polymer has an intrinsic viscosity of 10. 0dL / g or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for preventing adhesion and clogging of mineral raw materials, and more particularly to a method for preventing adhesion and clogging of mineral raw materials that exhibits an excellent modification effect (reduced adhesion) even when an excessive amount of w / o emulsion polymer is brought into contact with the mineral raw materials. [Background technology]

[0002] Mineral raw materials, including coal and iron ore, are extracted from mines and transported by conveyor belts, freight cars, cargo ships, trucks, and other transport and processing equipment to storage and processing facilities inside and outside the mining site, where they are stored, stored, and processed.The mineral raw materials are then transported by transport and processing equipment to facilities that use the mineral raw materials (steel mills, thermal power plants, factories, etc.), where they are used. At such mining sites, storage facilities, processing facilities, and utilization facilities, mineral raw materials are usually stored in raw material yards as inventory. Mineral raw materials stored in raw material yards may contain rainwater or water sprayed as a dust prevention measure during storage and cleaning, and therefore tend to have a high moisture content.

[0003] For example, when coal, a type of mineral raw material stored in a raw material yard, is supplied to a boiler at a thermal power plant, the coal is generally transported to the boiler via a series of lines, including a belt conveyor, a coal pulverizer, and a bucket conveyor. If the coal being transported to the boiler is wet, the wet coal is likely to adhere to the contact surfaces of the piping (coal feed pipe) that supplies the coal to the boiler, and the belt conveyor, chute, hopper, and other processing equipment, and may further adhere and clog the piping.

[0004] When such adhesion or clogging occurs, it has conventionally been necessary to stop operation of the line and remove the clogged coal or disassemble the transfer and processing equipment to clear the adhesion or clogging, which reduces the efficiency of coal transfer and further reduces the power generation efficiency at thermal power plants.

[0005] To address this problem, a known method is to bring a modifier (such as a polymer (high molecular weight compound) with excellent water absorption and water retention properties) into contact with the mineral raw material (spraying, adding, etc.) to modify the properties of the mineral raw material (reducing adhesion, reducing fluidity, etc.). Methods for contacting mineral raw materials with modifiers include spraying the modifier onto mineral raw materials piled up in a raw material yard or spraying a fixed amount of modifier from above the mineral raw materials as they are transported on a conveyor belt or other transport equipment. However, these methods often fail to ensure that a given amount of modifier is always in contact with a given quality (e.g., moisture content) and quantity of mineral raw materials. That is, some portions of the mineral raw materials may be in contact with an excess amount of modifier compared to other portions. Furthermore, when a polymer (high molecular weight compound) is used as a modifier, contacting an excessive amount of polymer (high molecular weight compound) with the mineral raw materials can cause spinnability due to the polymer's properties, which can actually increase the adhesiveness of the mineral raw materials. Therefore, a method for preventing adhesion and clogging of mineral raw materials by contacting a modifier with a mineral raw material is desired to exhibit excellent modification effects (reduced adhesiveness) even when an excessive amount of modifier is in contact with the mineral raw materials.

[0006] Patent Document 1 discloses that by adding a water-soluble polymer compound (anionic w / o emulsion polymer: modifier) ​​to a coal and / or iron ore slurry and mixing it, the fluidity of the coal and / or iron ore slurry can be reduced, and the resulting modified product is stable and easy to handle. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-214292 Summary of the Invention [Problem to be solved by the invention]

[0008] However, the above-mentioned Patent Document 1 had a problem in that when an excessive amount of a water-soluble polymer compound (anionic w / o emulsion polymer: modifier) ​​was brought into contact with the mineral raw material, it did not exhibit an excellent modifying effect (reduction in adhesion).

[0009] The present invention has been made in view of the above circumstances, and aims to provide a method for preventing adhesion and clogging of mineral raw materials, which shows an excellent modification effect (reduced adhesion) even when an excessive amount of w / o emulsion polymer comes into contact with the mineral raw materials. [Means for solving the problem]

[0010] The present invention is based on the finding that a cationic w / o emulsion polymer having a predetermined intrinsic viscosity exhibits an excellent modifying effect (reduced adhesion) even when contacted with an excessive amount of mineral raw material.

[0011] That is, the present invention provides the following [1] to [8]. [1] A method for preventing adhesion and clogging of mineral raw materials, comprising at least one of transporting and processing a raw material mixture in which a cationic w / o emulsion polymer is contacted with a mineral raw material in a transport processing facility, and preventing adhesion and clogging in the transport processing facility for the mineral raw materials, The method for preventing adhesion and clogging of mineral raw materials, wherein the cationic w / o emulsion polymer has an intrinsic viscosity of 10.0 dL / g or less. Here, the intrinsic viscosity of the cationic w / o emulsion polymer is determined according to the following procedures (i) to (v). (i) Immerse five Cannon-Fenske viscometers (No. 75, manufactured by Kusano Chemical Co., Ltd.) in a neutral detergent for glassware for at least one day, then wash thoroughly with water and dry. (ii) A cationic w / o emulsion polymer is diluted with water to prepare an aqueous solution with a polymer concentration of 0.2% by mass. (iii) 50 mL of a 2 mol / L sodium nitrate solution was added to 50 mL of the 0.2% polymer solution prepared in (ii) above, and the mixture was stirred at 500 rpm for 20 minutes using a magnetic stirrer to obtain a 1 mol / L sodium nitrate solution with a 0.1% polymer concentration. This solution was then diluted with 1 mol / L sodium nitrate to prepare five polymer solution samples with concentrations of 0.02, 0.04, 0.06, 0.08, and 0.1% by mass. A 1 mol / L sodium nitrate solution without added polymer served as a blank solution. (iv) Install the five viscometers prepared in (i) vertically in a thermostatic water bath adjusted to a temperature of 30°C (within ±0.02°C). Add 10 mL of blank solution to each viscometer using a volumetric pipette, then leave the viscometer to stand for approximately 30 minutes to stabilize the temperature. Then, use a dropper to draw up the solution, allow it to fall naturally, and measure the time it takes to pass the marked line with a stopwatch to the nearest 1 / 100 second. This measurement is repeated five times for each viscometer, and the average value is taken as the blank value (t0). (v) 10 mL of each of the polymer solution samples with five polymer concentrations prepared in (iii) is placed in the five viscometers used to measure the blank solution, and allowed to stand for approximately 30 minutes to stabilize the temperature. The same procedure as for measuring the blank solution is then repeated three times, and the average value of the transit time for each concentration is taken as the measured value (t). From the blank value t0, the measured value t, and the concentration of the polymer solution sample [mass / volume %] (= C [g / dL]), the relative viscosity η is calculated from the following equations (II) and (III): rel , specific viscosity η SP and reduced viscosity η SP Calculate / C [dL / g]. η rel =t / t0 (II) η SP =(t-t0) / t0=η rel -1···(III) From these values, the intrinsic viscosity [η] of each polymer is calculated according to the following method of calculating the intrinsic viscosity [η] based on the Huggins equation. The method of calculating the intrinsic viscosity [η] is to prepare a plurality of polymer solution samples with different polymer concentrations, and calculate the specific viscosity η of the polymer solution samples with each concentration. SP Calculate the vertical axis as η SPThis refers to a method of plotting the viscosity on a graph with the horizontal axis at C and the horizontal axis at C, and then extrapolating C to 0 to determine the intercept (intrinsic viscosity [η]). η SP / C=[η]+k'[η] 2 ×C···Huggins formula k' = Huggins constant [2] The method for preventing adhesion and clogging of mineral raw materials according to [1] above, wherein the colloid equivalent value of the cationic w / o emulsion polymer is 5.0 meq / g or less. Here, the colloid equivalent value of the cationic w / o emulsion polymer is determined at pH 4 according to the following procedures (1) to (8). (1) At room temperature (25°C), using a magnetic stirrer, deionized water is stirred at 1500 rpm. The cationic w / o emulsion polymer is quickly poured into the vortex along the inner surface of the vortex to achieve a polymer concentration of 0.2% by mass, and the mixture is stirred for 1 hour. If the polymer is not fully dissolved, the mixture is stirred for an additional hour. The mixture is then left to stand overnight at room temperature until it dissolves. (2) Measure 25 mL of the aqueous solution with a polymer concentration of 0.2% by mass prepared in (1) using a volumetric pipette, place it in a 200 mL measuring cylinder, fill it up with deionized water, and stir by inversion to prepare an aqueous solution with a polymer concentration of 250 mg / L (measurement sample). (3) Prepare four conical beakers, pour 80 mL of deionized water into each conical beaker, add 20 mL of the measurement sample prepared in (2), and stir thoroughly with a magnetic stirrer to prepare each sample for titration. (4) Adjust the pH of each sample to 3, 5, 7, or 9 by adding aqueous hydrochloric acid or aqueous sodium hydroxide solution while checking with a pH meter. (5) Immediately add 1 to 2 drops of toluidine blue as an indicator to each of the samples to be titrated, which have been adjusted to pH 3, 5, 7, and 9, and stir for 10 seconds. (6) Immediately afterwards, titrate with stirring at a rate of 2 mL / min using a 0.0025 mol / L (1 / 400N) standard solution of potassium polyvinyl sulfate as the titrant. Determine the titration volume D mL when the color changes from blue to pink and remains pink for 10 seconds or more. (7) On the other hand, titration is also performed on deionized water in the same manner as for the titration sample, and the blank titration volume E mL is determined. The colloid equivalent values ​​of the titration samples adjusted to pH 3, 5, 7, and 9 are calculated from the titration volume D mL and the blank titration volume E mL using the following formula. Colloid equivalent value [meq / g] = (titrant concentration (0.0025 mol / L) × (DmL - EmL)) / polymer amount in the measurement sample (g) (8) After the titration, measure the pH value of each of the titration samples adjusted to pH 3, 5, 7, and 9, and plot the measured pH values ​​on the X-axis of the graph and the colloid equivalent value calculated from the above formula on the Y-axis of the graph. Read the colloid equivalent value at the value corresponding to pH 4 from the curve connecting the four plotted points on the graph, and use this as the colloid equivalent value (meq / g) at pH 4. [3] The method for preventing adhesion and clogging of mineral raw materials according to [1] or [2] above, wherein the ratio of the colloid equivalent value to the intrinsic viscosity of the cationic w / o emulsion polymer (colloid equivalent value / intrinsic viscosity) is 0.5 meq / dL or more when the colloid equivalent value is 3.0 meq / g or more and the intrinsic viscosity is 4.0 to 10.0 dL / g. [4] A method for preventing adhesion and clogging of mineral raw materials according to any one of [1] to [3] above, wherein the transport processing equipment is at least one selected from the group consisting of a ship's hold, an unloader, a stacker, a raw material yard, a reclaimer, a pipe, a belt conveyor, a belt conveyor transfer section, a conveyor chain, a chute, a hopper, a silo, a blending tank, a crusher, a moisture-control coal facility, and a coal-loading car. [5] The method for preventing adhesion and clogging of mineral raw materials according to any one of [1] to [4] above, wherein the mineral raw material is at least one selected from the group consisting of coal, ore, dust, coke, and limestone. [6] The mineral raw material contains water; The method for preventing adhesion and clogging of mineral raw materials according to any one of [1] to [5] above, wherein the content of the water is 1.0 mass % or more relative to 100 mass % of the mineral raw materials. [7] A method for preventing adhesion and clogging of mineral raw materials described in any of [1] to [6] above, comprising a step of spraying the cationic w / o emulsion polymer onto the mineral raw materials at least either before or during transport in the transport processing equipment, thereby obtaining the raw material mixture. [8] A method for preventing adhesion and clogging of mineral raw materials described in any of [1] to [7] above, comprising the step of adding the cationic w / o emulsion polymer into a container containing the mineral raw materials, stirring and mixing, and obtaining the raw material mixture. [Effects of the Invention]

[0012] According to the present invention, a method for preventing adhesion and clogging of mineral raw materials can be provided, which shows an excellent modification effect (reduced adhesion) even when an excessive amount of w / o emulsion polymer comes into contact with the mineral raw materials. The method of the present invention may contribute to the efficient transportation or processing of mineral raw materials. DETAILED DESCRIPTION OF THE INVENTION

[0013] The present invention will be described in detail below. In this specification, the preferred definitions can be adopted arbitrarily, and it can be said that a combination of preferred definitions is more preferred. In this specification, the expression "XX to YY" as a range of values ​​means "XX or more and YY or less." In this specification, for preferred numerical ranges (e.g., ranges of content, etc.), the lower and upper limits described in stages can be independently combined. For example, the description "preferably 10 to 90, more preferably 30 to 60" can be combined with the "preferable lower limit (10)" and the "more preferable upper limit (60)" to form "10 to 60." Furthermore, in the numerical ranges described in this specification, the upper or lower limit of the numerical range may be replaced with a value shown in the examples. In this specification, the term "prevention of adhesion and clogging" is used to mean not only the case where adhesion and clogging do not occur at all, but also the case where adhesion and clogging occur partially, but the adhesion and clogging are sufficiently suppressed to the extent that the transport of the mineral raw material is not hindered. In this specification, the term "excessive amount" in "when an excessive amount of w / o emulsion polymer is brought into contact with a mineral raw material" refers to an amount at which spinnability can be confirmed (stringiness can be visually recognized) when Modifier 4 (anionic w / o emulsion polymer) of Synthesis Example 4 disclosed in this specification is brought into contact with the mineral raw material.

[0014] [Method for preventing adhesion and clogging of mineral raw materials] A method for preventing adhesion and clogging of mineral raw materials according to an embodiment of the present invention comprises transporting and / or processing a raw material mixture obtained by contacting a cationic w / o emulsion polymer with a mineral raw material, particularly a wet mineral raw material or a slurry-like mineral raw material, in a transport and processing facility, thereby preventing adhesion and clogging of the mineral raw material in the transport and processing facility, wherein the intrinsic viscosity of the cationic w / o emulsion polymer is 10.0 dL / g or less. The surface of the mineral raw materials is modified by contacting the cationic w / o emulsion polymer, which reduces adhesion of the mineral raw materials to the contact surfaces of the transporting and processing equipment, thereby preventing adhesion and clogging of the mineral raw materials in the transporting and processing equipment.

[0015] (mineral raw materials) The type of mineral raw material is not particularly limited, and examples thereof include coal, ore, dust, coke, limestone, oil coke, semi-coke, etc. These may be used alone or in combination of two or more. Among these, coal, ore, dust, coke, and limestone are preferred, coal and ore are more preferred, coal and iron ore are even more preferred, and coal is particularly preferred. The ore is not particularly limited, and examples thereof include gold ore, silver ore, copper ore, lead ore, iron ore, bismuth ore, bell ore, antimony ore, mercury ore, zinc ore, chromium ore, etc. These may be used alone or in combination of two or more.

[0016] The shape of the mineral raw material is not particularly limited, and examples thereof include granular and powder forms.

[0017] The particle size of the mineral raw material is not particularly limited, but is preferably 10.0 mm or less, more preferably 0.1 to 7.0 mm, and particularly preferably 1.0 to 5.0 mm. The particle size of the mineral atoms can be determined by the measurement method described in the Examples.

[0018] In this specification, "wet mineral raw material" means a mineral raw material in which moisture is present on the particle surface, and "slurry mineral raw material" means a fluid mineral raw material in which particles are suspended in a liquid. The moisture content (moisture content) of wet mineral raw materials and slurry mineral raw materials varies depending on the type and properties of the mineral raw materials and cannot be generally determined, but when the moisture content is 1 to 10 mass% out of 100 mass% of the mineral raw materials, it can be said to be in a wet state, and when it is more than 10 mass%, it can be said to be in a slurry state. When the mineral raw material is coal, a moisture content of 1 to 12 mass% in 100 mass% coal can be said to be in a wet state, and a moisture content of more than 12 mass% can be said to be in a slurry state. When the mineral raw material is iron ore, it can be said to be in a wet state when the moisture content is 1 to 9 mass% in 100 mass% of iron ore, and in a slurry state when it exceeds 9 mass%. The origin of the water in the mineral raw materials is not particularly limited, and may be derived from the mineral raw materials themselves, or from water that comes into contact with the mineral raw materials during transportation or storage, or water that is sprayed to prevent dust.

[0019] The moisture content of the mineral raw material is not particularly limited, but from the viewpoint of fully achieving the effect of the present invention (providing a method for preventing adhesion and clogging of mineral raw materials that exhibits an excellent modification effect (reduced adhesion) even when an excessive amount of w / o emulsion polymer comes into contact with the mineral raw material), conditions requiring an excessive amount of w / o emulsion polymer, i.e., conditions with a high moisture content, are said to be suitable, and the moisture content is preferably 1 mass% or more, more preferably 7 mass% or more, even more preferably 10 mass% or more, and particularly preferably 15 mass% or more, based on 100 mass% of the mineral raw material. Furthermore, when the mineral raw material is coal, the moisture content of the coal is not particularly limited. However, from the viewpoint of fully achieving the effect of the present invention (i.e., providing a method for preventing adhesion and clogging of mineral raw materials that exhibits an excellent modification effect (reduced adhesion) even when an excessive amount of w / o emulsion polymer comes into contact with the mineral raw material), conditions requiring an excessive amount of w / o emulsion polymer, i.e., conditions with a high moisture content, are considered to be suitable, and the moisture content is preferably 10% by mass or more, more preferably 15% by mass or more, and particularly preferably 20% by mass or more, based on 100% by mass of coal. Furthermore, when the mineral raw material is iron ore, the moisture content of the iron ore is not particularly limited. However, from the viewpoint of fully achieving the effect of the present invention (i.e., providing a method for preventing adhesion and clogging of mineral raw materials that exhibits an excellent modification effect (reduced adhesion) even when an excessive amount of w / o emulsion polymer comes into contact with the mineral raw material), conditions requiring an excessive amount of w / o emulsion polymer, i.e., conditions with a high moisture content, are considered to be suitable, and the moisture content is preferably 5% by mass or more, and more preferably 8% by mass or more, based on 100% by mass of iron ore. The moisture content of mineral raw materials, coal, etc. can be determined by the measurement method described in the Examples.

[0020] (cationic w / o emulsion polymer) The cationic w / o emulsion polymer is not particularly limited, and examples thereof include homopolymers and copolymers composed of (i) nonionic monomers such as (meth)acrylic acid esters, (meth)acrylamides, and oxyalkylenes; and (ii) cationic monomers such as alkyleneimines, (meth)acrylic acid N-alkylaminoalkyl esters, and (meth)acrylic acid N-alkylaminoalkyl ester quaternary salts. In this specification, "(meth)acrylic" means "acrylic" or "methacrylic".

[0021] The (meth)acrylic acid ester is not particularly limited, and examples thereof include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, hydroxyethyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. The oxyalkylene is not particularly limited, and examples thereof include ethylene oxide and propylene oxide. The (meth)acrylamide is not particularly limited, and examples thereof include (meth)acrylamide, N-ethyl(meth)acrylamide, etc. Among these, (meth)acrylamide is preferred, and acrylamide is more preferred. The alkyleneimine is not particularly limited, and examples thereof include ethyleneimine and methylethyleneimine. The monomer constituting the (meth)acrylic acid N-alkylaminoalkyl ester is not particularly limited, and examples thereof include 2-dimethylaminoethyl (meth)acrylate. The monomer constituting the (meth)acrylic acid N-alkylaminoalkyl ester quaternary salt is not particularly limited, and examples thereof include 2-(meth)acrylic acid trimethylammonium ethyl chloride, 2-(meth)acrylic acid dimethylethylammonium ethyl chloride, etc. Among these, 2-(meth)acrylic acid trimethylammonium ethyl chloride is preferred. The above monomers may be used alone or in combination of two or more.

[0022] The cationic w / o emulsion polymer is not particularly limited, but from the viewpoint of availability, a polymer composed of a (meth)acrylic acid N-alkylaminoalkyl ester quaternary salt and a copolymer composed of (meth)acrylamide and a (meth)acrylic acid N-alkylaminoalkyl ester quaternary salt are preferred, a polymer composed of a methacrylic acid N-alkylaminoalkyl ester quaternary salt and a copolymer composed of acrylamide and an acrylic acid N-alkylaminoalkyl ester quaternary salt are more preferred, and a polymer composed of 2-methacrylic acid trimethylammonium ethyl chloride and a copolymer composed of 2-acrylic acid trimethylammonium ethyl chloride and acrylamide are particularly preferred. The cationic w / o emulsion polymer may be used alone or in combination of two or more kinds.

[0023] The cationic w / o emulsion polymer may or may not have a crosslinked structure. Such a crosslinked structure can be formed by using a crosslinking agent, if necessary, during the production of the cationic w / o emulsion polymer. The crosslinking agent is not particularly limited, and examples thereof include N,N'-methylenebis(meth)acrylamide, triallylamine, ethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, 1,3-butylene glycol di(meth)acrylate, triallylamine, ethoxylated isocyanuric acid tri(meth)acrylate, etc. These may be used alone or in combination of two or more.

[0024] The amount of cationic w / o emulsion polymer to be brought into contact with the mineral raw material is adjusted appropriately depending on the water content of the mineral raw material, the type of cationic w / o emulsion polymer, etc., and is not particularly limited, but is preferably 0.005 to 0.500 mass%, more preferably 0.010 to 0.300 mass%, and particularly preferably 0.020 to 0.200 mass%, relative to 100 mass% of the mineral raw material. Furthermore, when the mineral raw material is coal, the amount of cationic w / o emulsion polymer to be brought into contact with the coal is not particularly limited, but is preferably 0.005 to 0.500 mass%, more preferably 0.010 to 0.300 mass%, and particularly preferably 0.020 to 0.200 mass%, relative to 100 mass% of the coal. Furthermore, when the mineral raw material is iron ore, the amount of cationic w / o emulsion polymer to be brought into contact with the iron ore is not particularly limited, but is preferably 0.005 to 0.500 mass%, more preferably 0.010 to 0.300 mass%, and particularly preferably 0.020 to 0.200 mass%, relative to 100 mass% of the iron ore. When the content is equal to or greater than the lower limit of the above range, the effect of reducing the adhesion of mineral raw materials is easily exhibited, whereas when the content is equal to or less than the upper limit of the above range, it is economically advantageous and adhesion is easily reduced.

[0025] The intrinsic viscosity of the cationic w / o emulsion polymer is not particularly limited as long as it is 10.0 dL / g or less, but is preferably 1.0 to 10.0 dL / g, more preferably 2.0 to 9.0 dL / g, and particularly preferably 3.0 to 8.0 dL / g. When the content is equal to or greater than the lower limit of the above range, the effect of reducing the adhesion of mineral raw materials is easily exhibited, and when the content is equal to or less than the upper limit of the above range, the occurrence of spinnability due to the polymer is less likely to occur. The intrinsic viscosity of the cationic w / o emulsion polymer can be determined by the measurement method described in the Examples.

[0026] The colloid equivalent value of the cationic w / o emulsion polymer is not particularly limited, but is preferably 5.0 meq / g or less, more preferably 0.1 to 5.0 meq / g. When the content is equal to or greater than the lower limit of the above range, the effect of reducing the adhesion of mineral raw materials is easily exhibited. The colloid equivalent value of the cationic w / o emulsion polymer can be determined by the measurement method described in the Examples.

[0027] The ratio of the colloid equivalent to the intrinsic viscosity of the cationic w / o emulsion polymer (colloid equivalent / intrinsic viscosity) is not particularly limited, but when the colloid equivalent is 3.0 meq / g or more and the intrinsic viscosity is 4.0 to 10.0 dL / g, it is preferably 0.5 meq / dL or more, more preferably 0.5 to 1.7 meq / dL.

[0028] The method for producing the cationic w / o emulsion polymer is not particularly limited, and examples thereof include reverse phase suspension polymerization, aqueous solution polymerization, and emulsion polymerization. Inverse phase suspension polymerization, a monomer mixture containing the above-mentioned monomers, a polymerization catalyst, an aqueous solution containing a crosslinking agent, etc., is suspended in an organic solvent (hexane, toluene, etc.) with a dispersant, and polymerization is carried out at a constant temperature (e.g., 60 to 80°C). After polymerization, the organic solvent is removed by centrifugal dehydration or the like, and then water is removed using a dryer or the like to obtain a pearl-like cationic w / o emulsion polymer. On the other hand, aqueous solution polymerization methods include an adiabatic polymerization method in which water is used as a solvent and a mixed solution containing the above-mentioned monomers, a polymerization catalyst, a crosslinking agent, etc. is polymerized in a reaction vessel, and a belt polymerization method in which the mixed solution is polymerized on a continuously moving belt conveyor. After polymerization, the polymer obtained by aqueous solution polymerization is dried to remove moisture and then pulverized (crushed) to adjust the particle size distribution. The emulsion polymerization method is a method in which an oil phase containing an oily solvent and a surfactant is prepared, an aqueous solution of a monomer is added to the oil phase, and the mixture is stirred and mixed to emulsify the mixture for polymerization. If the polymerization initiator is water-soluble, it may be mixed in the aqueous solution of the monomer, or if it is oil-soluble, it may be added after emulsification.

[0029] (Transportation and processing equipment) The term "transportation and processing equipment" as used herein is not particularly limited, and refers to, for example, equipment in a transfer line that sends mineral raw materials along a predetermined line from a ship's hold, through a storage location for mineral raw materials such as a raw material yard, to equipment that uses the mineral raw materials. Specific examples include ship's hold, unloader, stacker, raw material yard, reclaimer, piping, belt conveyor, belt conveyor transfer section, conveyor chain, chute, hopper, silo, blending tank, crusher, moisture-controlled coal equipment, and coal loading car. These may be used alone or in combination of two or more. Note that this also includes chutes, hoppers, silos, and other equipment that have a temporary storage function, and is to be distinguished from transportation by ship or truck, transport by bucket, etc. The present invention provides an excellent prevention effect against adhesion and clogging in areas of transport and processing equipment that are particularly prone to problems due to adhesion and clogging, specifically, piping, belt conveyors, conveyor chains, chutes, hoppers, silos, etc. Mineral raw materials are prone to adhesion and clogging in these transport and processing facilities, and if a blockage occurs, as described above, it is necessary to stop operation of the line and clear the blockage, which is time-consuming. In contrast, according to the present invention, mineral raw materials are less likely to adhere to the contact surfaces of the transport processing equipment, which makes it possible to easily prevent clogging of the transport processing equipment with mineral raw materials without stopping line operation, thereby efficiently and stably improving transportability.

[0030] (raw material mixture) The raw material mixture is a mixture of a mineral raw material and a cationic w / o emulsion polymer obtained by contacting a mineral raw material with a cationic w / o emulsion polymer. When the cationic w / o emulsion polymer comes into contact with the mineral raw material, at least a portion of the moisture in the mineral raw material is absorbed by the cationic w / o emulsion polymer, reducing the moisture content on the surface of the mineral raw material and reducing the adhesiveness of the mineral raw material to the contact surfaces of the transfer and treatment equipment. Note that it is not necessary for the entire amount of moisture in the mineral raw material to be absorbed by the cationic w / o emulsion polymer, as long as the adhesiveness to the contact surfaces of the transfer and treatment equipment is suppressed.

[0031] The method for contacting the mineral raw material with the cationic w / o emulsion polymer to obtain a raw material mixture is not particularly limited, but it is preferable to obtain a raw material mixture in which the mineral raw material and the cationic w / o emulsion polymer are uniformly mixed and in contact with each other. The position where the cationic w / o emulsion polymer is brought into contact is not particularly limited, and examples thereof include before, during, and after the mineral raw material is transferred by a transfer treatment facility such as a belt conveyor. These may be carried out at one location alone or at two or more locations in combination. For example, a raw material mixture can be obtained by spraying the cationic w / o emulsion polymer onto the mineral raw materials at least either before or during transport (before, during, or both before and during transport) on a transport treatment facility such as a belt conveyor. Among these, from the viewpoints of reducing the number of steps and convenience, it is preferable to spray the cationic w / o emulsion polymer onto the mineral raw materials before or during transport, and it is more preferable to spray the cationic w / o emulsion polymer onto the mineral raw materials from above during transport on a transport treatment facility such as a belt conveyor. Alternatively, the raw material mixture can be obtained by adding the cationic w / o emulsion polymer to a predetermined container containing the mineral raw materials and stirring and mixing them. Furthermore, the raw material mixture can also be obtained by scattering the cationic w / o emulsion polymer in a yard where raw materials are stored and mixing them with heavy machinery, a kneader, or the like.

[0032] The method for contacting the cationic w / o emulsion polymer with the mineral raw material is not particularly limited, and examples thereof include spraying, air pressure feeding, and screw feeder. The method for mixing the cationic w / o emulsion polymer with the mineral raw material is not particularly limited, and examples thereof include a method of mixing the mineral raw material with the cationic w / o emulsion polymer using heavy machinery; a mixing method utilizing the impact of a transfer point on a belt conveyor; and a mixing method using a mixing device such as a mixer. [Example]

[0033] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0034] <Measurement of moisture content in mineral raw materials> The moisture content of the mineral raw material was calculated by measuring the mass (A) of approximately 5 g of the mineral raw material, drying it in a dryer at 105°C for 2 hours, and then measuring the mass (B).The weight loss (AB) was considered to be the moisture content and calculated using the following formula. Moisture content [mass%]=(AB) / A×100

[0035] <Measuring particle size in mineral raw materials> The particle size of the mineral atoms was measured using the sieving test method (dry sieving method) of JIS Z 8815:1994.

[0036] <Measurement of intrinsic viscosity of cationic w / o emulsion polymer> The intrinsic viscosity of the cationic w / o emulsion polymer was determined according to the following procedures (i) to (v). (i) Five Cannon-Fenske viscometers (No. 75, manufactured by Kusano Chemical Co., Ltd.) were immersed in a neutral detergent for glassware for at least one day, then thoroughly washed with water and dried. (ii) A cationic w / o emulsion polymer was diluted with water to prepare an aqueous solution with a polymer concentration of 0.2% by mass. (iii) 50 mL of a 2 mol / L aqueous solution of sodium nitrate was added to 50 mL of the 0.2% polymer solution prepared in (ii) above, and the mixture was stirred at 500 rpm for 20 minutes using a magnetic stirrer to obtain a 1 mol / L aqueous solution of sodium nitrate with a 0.1% polymer concentration. This was then diluted with a 1 mol / L aqueous solution of sodium nitrate to prepare polymer solution samples with five different polymer concentrations: 0.02, 0.04, 0.06, 0.08, and 0.1% by mass. A 1 mol / L aqueous solution of sodium nitrate without added polymer was used as a blank solution. (iv) Five viscometers prepared in (i) were installed vertically in a thermostatic water bath adjusted to a temperature of 30°C (within ±0.02°C). 10 mL of blank solution was added to each viscometer using a volumetric pipette, and the viscometers were left to stand for approximately 30 minutes to stabilize the temperature. The liquid was then drawn up using a dropper and allowed to fall naturally. The time it took for the liquid to pass the marked line was measured to the nearest 1 / 100 second using a stopwatch. This measurement was repeated five times for each viscometer, and the average value was taken as the blank value (t0). (v) 10 mL of each of the polymer solution samples with five polymer concentrations prepared in (iii) was placed in the five viscometers used to measure the blank solution, and allowed to stand for approximately 30 minutes to stabilize the temperature. The same procedure as for measuring the blank solution was then repeated three times, and the average value of the transit time for each concentration was taken as the measured value (t). From the blank value t0, the measured value t, and the concentration of the polymer solution sample [mass / volume %] (= C [g / dL]), the relative viscosity η was calculated from the following equations (II) and (III): rel , specific viscosity η SP and reduced viscosity η SP / C [dL / g] was calculated. η rel =t / t0 (II) η SP =(t-t0) / t0=η rel -1···(III) From these values, the intrinsic viscosity [η] of each polymer was calculated according to the following Huggins equation: The intrinsic viscosity [η] was calculated by preparing a plurality of polymer solution samples with different polymer concentrations and calculating the specific viscosity η of each polymer solution sample. SP Calculate the vertical axis as η SPThis refers to a method of plotting the viscosity on a graph with the horizontal axis at C and the horizontal axis at C, and then extrapolating C to 0 to determine the intercept (intrinsic viscosity [η]). η SP / C=[η]+k'[η] 2 ×C···Huggins formula k' = Huggins constant

[0037] <Measurement of colloid equivalent value of cationic w / o emulsion polymer> The colloid equivalent value of the cationic w / o emulsion polymer was determined at pH 4 according to the following procedures (1) to (8). (1) At room temperature (25°C), deionized water was stirred at 1500 rpm using a magnetic stirrer. The cationic w / o emulsion polymer was quickly poured into the vortex along the inner surface of the vortex to a polymer concentration of 0.2% by mass, and the mixture was stirred for 1 hour. If the polymer was not fully dissolved, the mixture was stirred for another hour. The mixture was then left to stand overnight at room temperature until it was dissolved. (2) 25 mL of the aqueous solution with a polymer concentration of 0.2% by mass prepared in (1) was measured using a volumetric pipette and placed in a 200 mL measuring cylinder. The cylinder was then filled up to the desired volume with deionized water and stirred by inversion to prepare an aqueous solution with a polymer concentration of 250 mg / L (measurement sample). (3) Four conical beakers were prepared, and 80 mL of deionized water was placed in each conical beaker. 20 mL of the measurement sample prepared in (2) was then added, and the mixture was thoroughly stirred with a magnetic stirrer to prepare the titration samples. (4) The pH of each sample to be titrated was adjusted to 3, 5, 7, or 9 by adding an aqueous solution of hydrochloric acid or an aqueous solution of sodium hydroxide while checking with a pH meter. (5) To each of the samples to be titrated, which had been adjusted to pH 3, 5, 7, and 9, 1 to 2 drops of toluidine blue were immediately added as an indicator and the samples were stirred for 10 seconds. (6) Then, immediately, titration was carried out with stirring at a rate of 2 mL / min using a 0.0025 mol / L (1 / 400N) standard solution of potassium polyvinyl sulfate as the titrant. The endpoint was the point at which the color changed from blue to pink and remained pink for 10 seconds or more, and the titer (D mL) was calculated. (7) On the other hand, deionized water was titrated in the same manner as the titration sample, and the blank titration volume E mL was calculated. The colloid equivalent values ​​of the titration samples adjusted to pH 3, 5, 7, and 9 were calculated from the titration volume D mL and the blank titration volume E mL using the following formula. Colloid equivalent value [meq / g] = (titrant concentration (0.0025 mol / L) × (DmL - EmL)) / polymer amount in the measurement sample (g) (8) After the titration, the pH values ​​of the titration samples adjusted to pH 3, 5, 7, and 9 were measured, and the measured pH values ​​were plotted on the X-axis of the graph, and the colloid equivalent values ​​calculated from the above formula were plotted on the Y-axis of the graph. The colloid equivalent value at a value corresponding to pH 4 was read from the curve connecting the four plotted points on the graph, and this was taken as the colloid equivalent value (meq / g) at pH 4.

[0038] <Colloid equivalent value measurement of anionic w / o emulsion polymer> The colloid equivalent value of the anionic w / o emulsion polymer was determined at pH 10.5 according to the following procedures (1) to (8). (1) At room temperature (25°C), deionized water was stirred at 1500 rpm using a magnetic stirrer. The anionic w / o emulsion polymer was quickly poured into the vortex along the inner surface of the vortex to achieve a polymer concentration of 0.2% by mass, and the mixture was stirred for 1 hour. If the polymer was not fully dissolved, the mixture was stirred for another hour. The mixture was then left to stand overnight at room temperature until it was dissolved. (2) 25 mL of the aqueous solution with a polymer concentration of 0.2% by mass prepared in (1) was measured using a volumetric pipette and placed in a 200 mL measuring cylinder. The cylinder was then filled up to the desired volume with deionized water and stirred by inversion to prepare an aqueous solution with a polymer concentration of 250 mg / L (measurement sample). (3) Conical beakers were prepared, and 80 mL of deionized water was placed in each conical beaker. Sodium hydroxide solution was added using a pH meter to adjust the pH to 10-11. (4) 10 mL of 0.0025 mol / L (1 / 400N) methyl glycol chitosan solution was added dropwise and stirred for 1 minute. (5) While stirring, 20 mL of the sample was added, and after stirring for 5 minutes, it was confirmed that the pH of the solution was 10 or higher. (6) One to two drops of toluidine blue as an indicator was immediately added to each of the prepared titration samples, and the mixture was stirred for 10 seconds. (7) Immediately after the titration, the solution was titrated with 0.0025 mol / L (1 / 400N) standard solution of potassium polyvinyl sulfate as the titrant at a rate of 2 mL / min while stirring. The endpoint was the point at which the color changed from blue to pink and remained pink for 10 seconds or more, and the titer (F mL) was calculated. The pH after titration was confirmed to be 10 or higher. (8) On the other hand, deionized water was titrated at pH 10 in the same manner as for the titration sample, and the blank titration volume (GmL) was calculated. The colloid equivalent value of the titration sample adjusted to pH 10 or higher was calculated from the titration volume (FmL) and the blank titration volume (GmL) using the following formula. Colloid equivalent value [meq / g] = (titrant concentration (0.0025 mol / L) × (FmL - GmL)) / polymer amount in the measurement sample (g)

[0039] [Synthesis of cationic w / o emulsion polymers and anionic w / o emulsion polymers] Cationic w / o emulsion polymers (modifiers 1 to 3, 6, and 7) and anionic w / o emulsion polymers (modifiers 4 and 5) were synthesized using the following monomers as shown in the synthesis examples below. The following syntheses were also carried out using emulsion polymerization.

[0040] (monomer) DAA: 2-acrylic acid trimethylammonium ethyl chloride (2-(acryloyloxy)ethyltrimethylammonium chloride): structural formula (1) [ka] DAM: 2-methacrylic acid trimethylammonium ethyl chloride (2-(methacryloyloxy)ethyltrimethylammonium chloride): structural formula (2) below [ka] AAM: Acrylamide AAN: Ammonium acrylate

[0041] (Synthesis Example 1) 40 parts by mass of DAM, 30 parts by mass of normal paraffin, and 30 parts by mass of water were mixed and emulsified with stirring. The mixture was adjusted to 50°C while stirring, and nitrogen gas was bubbled through for 30 minutes. Under a nitrogen gas stream, a 4% by mass toluene solution of 2,2'-azobis(2-methylpropionamidine) dihydrochloride was added as a polymerization initiator, and polymerization was carried out at 45 to 55°C for 8 hours to obtain Modifier 1. Table 1 shows the monomers used in the synthesis of Modifier 1 and their physical properties.

[0042] (Synthesis Example 2) DAA and AAM were used in a mass ratio of 60 / 40 instead of DAM in Synthesis Example 1. In addition, a crosslinking agent (N,N'-methylenebisacrylamide) that was not used in Synthesis Example 1 was stirred and mixed with DAA and AAM to form an emulsion. Except for the above, Modifier 2 was obtained in the same manner as in Synthesis Example 1. Table 1 shows the monomers used in the synthesis of Modifier 2 and various physical properties.

[0043] (Synthesis Examples 3 to 7) Modifiers 3 to 7 were obtained in the same manner as in Synthesis Example 1, except that the monomers and mass ratios shown in Table 1 were used instead of DAM in Synthesis Example 1. Table 1 shows the monomers used in the synthesis of Modifiers 3 to 7 and their various physical properties.

[0044] [Table 1]

[0045] [Mineral raw materials] Coal 1: Moisture content: adjusted to 15% by mass in 100% coal, particle size: adjusted to 5 mm or less, moist coal (moist mineral raw material), granular Coal 2: Moisture content: adjusted to 20% by mass in 100% coal by mass, particle size: adjusted to 5 mm or less, slurry coal (slurry mineral raw material), granular Iron ore 1; moisture content: adjusted to 8.5% by mass in 100% iron ore; particle size: adjusted to 5 mm or less; wet iron ore (wet mineral raw material), granular

[0046] [Vibration test equipment] The "Adhesion Evaluation Test" and "Modification Ability Evaluation Test" described below were measured and evaluated using the following vibration tester. The vibration test equipment was equipped with a simulated hopper (feed inlet: 140 mm × 180 mm, discharge outlet: 30 mm × 60 mm, inverted square truncated pyramidal outer shape (length: 160 mm, vertical distance: 110 mm, internal surface area: 65600 mm) mounted on top of an electric sieve (manufactured by Nitto Kagaku Co., Ltd., ANF-30) instead of the vibrating sieve. 2 , angle: 70°, made of steel).

[0047] Example 1 <Adhesion evaluation test> A raw material mixture was prepared by adding 1 g of modifier 1 to 500 g of mineral raw material, Coal 1 or Coal 2, or by adding 2 g of modifier 1 to 1,000 g of mineral raw material, Iron Ore 1, and uniformly stirring and mixing. Note that the amount of modifier 1 added above is based on the assumption that an excessive amount of modifier is added, and depending on the type of modifier and mineral raw material, spinnability due to the modifier may occur, which is a condition that raises concerns about increased adhesiveness of the mineral raw material. The adhesion evaluation test was carried out using the vibration tester described above. The adhesion was evaluated by charging the raw material mixture into the simulated hopper of the vibration tester, and measuring the time required for the raw material mixture to be completely discharged from the simulated hopper when vibration was applied (discharge time). The shorter the discharge time, the better the modification effect (reduced adhesion) even when an excessive amount of w / o emulsion polymer comes into contact with the mineral raw material. The discharge times for only Coal 1 (500 g), Coal 2 (500 g), or Iron Ore 1 (1000 g) were undetectable. The above-mentioned non-detection means that due to adhesion and clogging, some or all of the raw material mixture or mineral raw materials could not be discharged even after 60 seconds, and the adhesion evaluation test was interrupted, so the discharge time could not be measured. The discharge time was used to evaluate whether clogging occurred or not according to the following evaluation criteria 1. The results are shown in Table 2. Furthermore, the appearance of the raw material mixture prepared above was visually inspected, and the presence or absence of spinnability due to the modifier was evaluated according to the following evaluation criteria 2. The results are shown in Table 2. [Evaluation Criteria 1 (presence or absence of clogging)] None: Discharge time less than 13.0 seconds Some: Ejection time 13.0~20.0 seconds Yes: Ejection time over 20.0 seconds When the evaluation is "no" to "slightly present," it can be said that the occurrence of clogging is suppressed. On the other hand, when the evaluation is "present," it cannot be said that the occurrence of clogging is suppressed. [Evaluation Criteria 2 (Appearance)] A: No stringiness (no visible stringiness or no visible stringiness) B: Stringiness present (stringiness was confirmed to the extent that it was visible) <Modification ability evaluation test> Using the vibration test device described above, the minimum amount (mass %) of modifier 1 required to achieve a discharge time of 10 seconds or less for a raw material mixture consisting of 500 g of mineral raw material (Coal 1, Coal 2, or Iron Ore 1) and modifier 1 was verified. The preparation of the raw material mixture (except for the amount of modifier 1 added) and measurement of the discharge time were performed using the same methods as those described in the above <Adhesion Evaluation Test>. The verification results (minimum amount (mass %) of modifier 1 required to achieve a discharge time of 10 seconds or less for 100 mass % of mineral raw material (Coal 1, Coal 2, or Iron Ore 1) are shown in Table 2. The smaller the amount of modifier required to achieve a discharge time of 10 seconds or less, the higher the modification ability. The appearance of the raw material mixture consisting of coal 1, coal 2, or iron ore 1 and the minimum required amount of modifier 1 was visually inspected, and the presence or absence of spinnability due to the modifier was evaluated according to the following evaluation criteria 3. The results are shown in Table 2. [Evaluation Criteria 3 (Appearance)] A: No stringiness (no visible stringiness or no visible stringiness) B: Stringiness present (stringiness was confirmed to the extent that it was visible)

[0048] (Examples 2 to 3, Comparative Examples 1 to 4) The <Adhesion evaluation test> and the <Modifying ability evaluation test> were carried out in the same manner as in Example 1, except that Modifiers 2 to 7 shown in Table 2 were used instead of Modifier 1 in Example 1.

[0049] The results of the above examples and comparative examples are summarized in Table 2.

[0050] [Table 2]

[0051] As can be seen from the results shown in Table 2, the Examples of the present invention (Examples 1 to 3, which used a cationic w / o emulsion polymer with an intrinsic viscosity of 10.0 dL / g or less) had a shorter discharge time in the adhesion evaluation test than the Comparative Examples not of the present invention (Comparative Examples 4 and 5, which used an anionic w / o emulsion polymer, and Comparative Examples 6 and 7, which used a cationic w / o emulsion polymer with an intrinsic viscosity of more than 10.0 dL / g). In other words, it was confirmed that even when an excessive amount of w / o emulsion polymer came into contact with the mineral raw material, an excellent modification effect (reduced adhesion) was exhibited. In addition to the above, it was confirmed that the Examples of the present invention (Examples 1 to 3 using a cationic w / o emulsion polymer with an intrinsic viscosity of 10.0 dL / g or less) had a lower mass % in the modification ability evaluation test when using Coal 2 (slurry-like mineral raw material (coal)) than the Comparative Examples not of the present invention (Comparative Examples 4 to 5 using an anionic w / o emulsion polymer and Comparative Examples 6 to 7 using a cationic w / o emulsion polymer with an intrinsic viscosity of more than 10.0 dL / g), i.e., had a higher modification ability. Coal is anionic, mainly consisting of aromatic structures, and contains phenolic hydroxyl groups and carbonyl groups. Therefore, we speculate that the cationic w / o emulsion is more likely to exhibit a reforming effect by being adsorbed onto coal through charge neutralization (the mass % of coal 2 in Examples 1 and 2 in the reforming ability evaluation test was 0.08 to 0.12). It is presumed that when the intrinsic viscosity of the cationic w / o emulsion polymer exceeds 10 dL / g, the intermolecular interactions increase, causing the molecules to become entangled, increasing the viscosity of the polymer solution and resulting in spinnability (the appearance of coal 1 in Comparative Examples 3 and 4 in the adhesion evaluation test was graded B).

Claims

1. A method for preventing adhesion and clogging of mineral raw materials, comprising at least one of transporting and processing a raw material mixture in which a cationic w / o emulsion polymer is contacted with a mineral raw material in a transport processing facility, and preventing adhesion and clogging of the mineral raw material transport processing facility, comprising: The method for preventing adhesion and clogging of mineral raw materials, wherein the cationic w / o emulsion polymer has an intrinsic viscosity of 10.0 dL / g or less.

2. 2. The method for preventing adhesion and clogging of mineral raw materials according to claim 1, wherein the colloid equivalent value of the cationic w / o emulsion polymer is 5.0 meq / g or less.

3. 3. The method for preventing adhesion and clogging of mineral raw materials according to claim 1 or 2, wherein the ratio of the colloid equivalent value to the intrinsic viscosity of the cationic w / o emulsion polymer (colloid equivalent value / intrinsic viscosity) is 0.5 meq / dL or more when the colloid equivalent value is 3.0 meq / g or more and the intrinsic viscosity is 4.0 to 10.0 dL / g.

4. 3. The method for preventing adhesion and clogging of mineral raw materials according to claim 1 or 2, wherein the transport processing equipment is at least one selected from the group consisting of a ship's hold, an unloader, a stacker, a raw material yard, a reclaimer, a pipe, a belt conveyor, a belt conveyor transfer section, a conveyor chain, a chute, a hopper, a silo, a blending tank, a crusher, a moisture-control coal facility, and a coal-loading car.

5. 3. The method for preventing adhesion and clogging of mineral raw materials according to claim 1 or 2, wherein the mineral raw materials are at least one selected from the group consisting of coal, ore, dust, coke, and limestone.

6. The mineral raw material contains water, 3. The method for preventing adhesion and clogging of mineral raw materials according to claim 1 or 2, wherein the content of the water is 1.0 mass % or more relative to 100 mass % of the mineral raw materials.

7. 3. A method for preventing adhesion and clogging of mineral raw materials as described in claim 1 or 2, comprising a step of spraying the cationic w / o emulsion polymer onto the mineral raw materials at least either before or during transportation in the transportation processing equipment, thereby obtaining the raw material mixture.

8. 3. The method for preventing adhesion and clogging of mineral raw materials according to claim 1, further comprising the step of adding the cationic w / o emulsion polymer into a container containing the mineral raw materials and stirring and mixing the mixture to obtain the raw material mixture.

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