AU2021238175A1 - Treatment method of moisture-containing bulk material, and flocculant adding device - Google Patents

Abstract

A method is provided which, even when continuously adding a polymer flocculant to moisture-containing bulk material conveyed on a conveyor belt, enables using simpler equipment to more uniformly add the polymer flocculant to moisture-containing bulk material.　This treatment method of moisture-containing bulk material, which involves adding a flocculant to moisture-containing bulk material conveyed on a conveyor belt, involves: using as the aforementioned flocculant a liquid dispersion that contains a polymer flocculant in a salt solution in a dispersed state; using a tube-shape member installed above the conveyor belt and having outlets which are provided in the peripheral wall along the long axis direction and which let the liquid dispersion flow out in the width direction of the conveyor belt; and adding the liquid dispersion from the outlets in the tube-shape member onto the moisture-containing bulk material on the conveyor belt.

Description

DESCRIPTION

Title of Invention TREATMENT METHOD OF MOISTURE-CONTAINING BULK MATERIAL, AND FLOCCULANT ADDING DEVICE

Technical Field

[0001] The present invention relates to a method for treating a water-containing bulk materials and a flocculant adding apparatus.

Background Art

[0002] Bulk materials such as iron ores and coal mined in mines are conveyed to storage sites called yards, processing facilities for bulk materials, facilities for use, and the like in the mining sites by conveyance means such as a belt conveyor, a wagon, and a truck. In addition, bulk materials such as iron ores and coal are conveyed and loaded onto ships from the mining sites by the above-described conveyance means, transported outside the mining sites, and unloaded outside the mining sites. Bulk materials unloaded outside the mining sites are again conveyed by conveyance means to storage sites, bulk material processing facilities, usage facilities, and the like (for example, steel works, power plants, and factories) outside the mining sites.

[0003] Bulk materials such as iron ores and coal are often in contact with water in mining fields, storage sites inside and outside the mining sites, and conveyance means such as a belt conveyor, a truck, and a ship (for example, on a belt conveyor and truck bed, and in a hold of a ship) by, for example, rainfall or sprinkling for dust prevention. Therefore, by the contact between the bulk materials and water, the bulk materials in the state of containing water (described herein as "water-containing bulk materials") are generated.

[0004] In addition, while a water-containing bulk material is transported by ship from the mining site outside the mining site, water in the water-containing bulk material separates from the bulk material due to the agitation, vibration, or the like of the ship and retains on the floor of the hold of the ship, and the water and the powder of the bulk material may be mixed to generate suspended free water. In this case, when the water-containing bulk material whose water content and fluidity have been further increased by containing suspended free water is unloaded from the ship and loaded onto the belt conveyor outside the mining site from where the water-containing bulk material has been transported, and conveyed with the belt conveyor, the water containing bulk material may cause a loading obstacle such as being likely to flow out from the belt conveyor.

[0005] In order to solve the loading obstacle in the case as described above, Patent Literature 1 has proposed a method including adding a chemical solution containing a polymer flocculant as a main component to a water-containing bulk material on a belt conveyor to make a floc composed of the water-containing bulk material and suspended free water, and then conveying the floc on a belt conveyor.

Citation List Patent Literature

[0006]Patent Literature 1: International Publication No. WO 2014/058074

Summary of Invention Technical Problem

[0007] According to the method disclosed in Patent Literature 1, even if suspended free water is generated in the hold of a ship during unloading and the water content of a bulk material increases, it is described in the literature that the bulk material can be conveyed without overflowing from the belt conveyor. Further, Patent

Literature 1 describes that the above-described chemical solution is sprinkled in the form of shower or sprayed in the form of mist on the water-containing bulk material on the belt conveyor to mix the water-containing bulk material and the chemical solution at a drop part of the junction part of the belt conveyor and thereby mixing of thereof and flocculation action of the polymer flocculant are accelerated, which can further improve unloading efficiency.

[00081 However, as a result of studies conducted by the present inventors, in the case where a chemical solution containing a polymer flocculant as a main component is added to a water-containing bulk material in the form of shower or in the form of mist, when continuous operation for a long time in an actual machine is assumed, it has been found that the discharge port of the member used for adding the chemical solution is likely to clog due to the chemical solution, and it may be difficult to add the chemical solution uniformly.

[00091 In addition, the presence or absence of a junction part of the belt conveyor, the installation position of the junction part, the height of the drop part of the junction part, the length of the belt conveyor, and the like vary depending on the facility, equipment, and the like. Therefore, for example, in equipment that does not have a junction part in the belt conveyor, equipment in which a junction part is almost free of a drop part or has a low drop part, and equipment in which the distance of the belt conveyor is short, it is considered that mixing of the water-containing bulk material and the chemical solution is insufficient and the water-containing bulk material and the chemical solution are unlikely to be mixed uniformly.

[0010] Accordingly, the present invention intends to provide a method by which even when a polymer flocculant is continuously added to a water-containing bulk material being conveyed with a belt conveyor, the polymer flocculant is likely to be added more uniformly to the water containing bulk material using simpler equipment. Further, the present invention intends to provide a flocculant adding apparatus that can be used for the method.

Solution to Problem

[0011] The present invention provides a method for treating a water-containing bulk material, including adding a flocculant to the water-containing bulk material being conveyed with a belt conveyor, the method including: using a dispersion liquid containing, as the flocculant, a polymer flocculant in the form of dispersion in an aqueous salt solution; using a tubular member wherein an outlet or outlets that allow the dispersion liquid to flow out over a width direction of the belt conveyor are provided in a peripheral wall along a major axis direction, the tubular member installed above the belt conveyor; and adding the dispersion liquid to the water-containing bulk material on the belt conveyor from the outlet or outlets of the tubular member. In addition, the present invention provides a method for treating a water-containing bulk material including adding a dispersion liquid containing a polymer flocculant in the form of dispersion in an aqueous salt solution to a water-containing bulk material.

[0012] Further, the present invention provides a flocculant adding apparatus that adds a flocculant to a water-containing bulk material being conveyed with a belt conveyor, the apparatus including: a tank that stores a dispersion liquid comprising, as the flocculant, a polymer flocculant in the form of dispersion in an aqueous salt solution; a tubular member that is installed above the belt conveyor, wherein an outlet or outlets that allow the dispersion liquid allowed to flow in an inside of the tubular member to flow out over a width direction of the belt conveyor are provided in a peripheral wall along a major axis direction; and a pump that transfers the dispersion liquid into the tubular member from the tank.

Advantageous Effects of Invention

[0013] The present invention can provide a method by which even when a polymer flocculant is continuously added to a water-containing bulk material being conveyed with a belt conveyor, the polymer flocculant is likely to be added more uniformly to the water-containing bulk material using simpler equipment. Further, the present invention can provide a flocculant adding apparatus that can be used for the method.

Brief Description of Drawings

[0014] [Figure 1] Figure 1 is a schematic side view showing one example of a configuration of a tubular member that can be used for a method for treating a water-containing bulk material and a flocculant adding apparatus of one embodiment of the present invention.

[Figure 2] Figure 2 is a partially enlarged diagram of a schematic plan view viewed from the front of outlets of the tubular member shown in Figure 1.

[Figure 3A] Figure 3A is a diagram for describing one example of installing a tubular member and is a schematic top view showing the tubular member together with a belt conveyor.

[Figure 3B] Figure 3B is a diagram for describing another example of installing a tubular member and is a schematic top view showing the tubular member together with a belt conveyor.

[Figure 4] Figure 4 is a schematic diagram showing one example of a configuration of a flocculant adding apparatus of one embodiment of the present invention.

[Figure 5] Figure 5 is a schematic plan view corresponding to Figure 2 and showing another example of the configuration of the tubular member that can be used for a method for treating a water-containing bulk material and a flocculant adding apparatus of one embodiment of the present invention.

[Figure 6] Figure 6 is a schematic side view corresponding to Figure 1 and showing still another example of the configuration of the tubular member that can be used for a method for treating a water-containing bulk material and a flocculant adding apparatus of one embodiment of the present invention.

Description of Embodiments

[00151 Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the following embodiments.

[0016] <Method for Treating Water-containing Bulk Material> A method for treating a water-containing bulk material of one embodiment of the present invention (hereinafter, sometimes simply referred to as "method for treating a water-containing bulk material") includes adding a flocculant to a water-containing bulk material being conveyed with a belt conveyor. This method includes using a dispersion liquid containing, as the flocculant, a polymer flocculant in the form of dispersion in an aqueous salt solution (hereinafter, sometimes simply referred to as "dispersion liquid"). In addition, this method includes using a tubular member installed above the belt conveyor. The tubular member is a tubular member wherein an outlet or outlets that allow the dispersion liquid to flow out over a width direction of the belt conveyor are provided in a peripheral wall along a major axis direction. Then, this method includes adding the dispersion liquid to the water containing bulk material on the belt conveyor from the outlet or outlets of the tubular member.

[0017] The dispersion liquid containing a polymer flocculant is used in this method for treating a water containing bulk material, and therefore clogging in the outlet or outlets of the member (tubular member) which is used for adding the dispersion liquid is unlikely to occur and the polymer flocculant is likely penetrate into the water-containing bulk material. In addition, the outlet or outlets that allow the dispersion liquid to flow out over the width direction of the belt conveyor are provided along the major axis direction in the peripheral wall of the tubular member which is used for adding the dispersion liquid, and therefore the dispersion liquid (polymer flocculant) can be added to the water-containing bulk material present over the width direction of the belt conveyor (the direction perpendicular to the running direction of the belt conveyor).

[0018] As described above, the dispersion liquid and the tubular member are used in the method for treating a water-containing bulk material, thereby the outlet or outlets of the tubular member are unlikely to clog, and the polymer flocculant is added to the water-containing bulk material present over the width direction of the belt conveyor and is likely to penetrate into the water containing bulk material, so that the polymer flocculant is likely to be added to the water-containing bulk material more uniformly. Specifically, even when the polymer flocculant is continuously added to the water-containing bulk material by continuous operation for a long time in an actual machine, or even if mixing of the water-containing bulk material and the polymer flocculant is not sufficiently secured owing to the circumstances of the equipment to which a belt conveyor is installed, a method by which the polymer flocculant is likely to added to the water-containing bulk material more uniformly can be provided.

[0019] When the dispersion liquid is added to the water-containing bulk material, the polymer flocculant in the dispersion liquid spreads over the entire water containing bulk material and the bulk material is flocculated due to the flocculation action by the polymer flocculant, so that water can be trapped in the gaps between the flocculated bulk materials. As a result, the fluidity of the water-containing bulk material can be lowered and the appearance of the water-containing bulk material can be modified into the state of aggregation or lump.

[0020] Therefore, for example, when a water-containing bulk material is conveyed with a belt conveyor at the mining site and is loaded onto a ship or the like, or when a water-containing bulk material that has been transported outside the mining site by a ship or the like is loaded on a belt conveyor and is conveyed, or when a water-containing bulk material is conveyed to storage sites, processing facilities, and usage facilities inside and outside the mining site, the method for treating a water-containing bulk material can suitably be utilized. As a result, effects such as facilitating loading operation for a water containing bulk material onto a ship or the like, suppression of collapse of the loaded water-containing bulk material, suppression of occurrence of a loading obstacle in loading the water-containing bulk material onto a belt conveyor or the like, suppression of occurrence of a conveyance obstacle caused by a belt conveyor or the like, suppression of occurrence of collapse of a conveyed and stacked water-containing bulk material, and suppression of dust generation by wind from a stacked water-containing bulk material can be expected.

[0021] (Water-containing Bulk Material) In the method for treating a water-containing bulk material of one embodiment of the present invention, a water containing bulk material being conveyed with a belt conveyor is the object of the treatment. Examples of the bulk material include iron ores, coal, limestone, coke, bauxite, and scrap iron. Among these, iron ores and coal are suitable, and iron ores are more suitable.

[0022] Water that causes the water-containing state in the water-containing bulk material is not particularly limited, and examples thereof include rainfall, sprinkling for dust prevention, suspended free water separated from the bulk material due to shaking, vibration, or the like of a ship transporting the bulk material, and retained on the floor of the hold of the ship. The water content (content of water) of the bulk material is preferably 1 to 50% by mass, more preferably 2 to 30% by mass, and still more preferably 5 to 20% by mass, based on the total mass of the water-containing bulk material.

[0023] Examples of the aspect of the water-containing bulk material being conveyed with a belt conveyor include bulk materials conveyed from the mining fields of the bulk materials in the mines to storage sites (yards), processing facilities, usage facilities, and the like in the mining sites with a belt conveyor; bulk materials conveyed from the mining fields (mines), storage sites, processing facilities, usage facilities, and the like to a ship and the like with a belt conveyor in the mining sites; and bulk materials transported outside the mining sites by ship or the like and conveyed to storage sites (yards), processing facilities, usage facilities, and the like (for example, steel works, power plants, and factories) outside the mining sites with a belt conveyor.

[0024] (Dispersion Liquid) In the method for treating a water-containing bulk material of one embodiment of the present invention, a dispersion liquid containing, as the flocculant to be added to the water-containing bulk material, a polymer flocculant in the form of dispersion in an aqueous salt solution is used. The product form of a chemical solution containing a polymer flocculant as a main component mainly includes a water-in-oil (W/O) type emulsion and a dispersion liquid. As a result of studies by experiments conducted by the present inventors, it has been found that the dispersion liquid is more likely to lower the fluidity of a water- containing bulk material than the W/O type emulsion even when the condition of mixing with the water-containing bulk material is calm. From this result, it is considered that the dispersion liquid is more likely to penetrate into the water-containing bulk material than the W/O type emulsion and thereby a polymer flocculant in the dispersion liquid is more likely to be dispersed into the water-containing bulk material than a polymer flocculant in the W/O type emulsion. In addition, it is considered that the dispersion liquid is more likely to be dissolved into water in the water-containing bulk material than the W/O type emulsion in which the dispersion medium contains oil in that the dispersion medium in the dispersion liquid is an aqueous salt solution, and therefore it is considered that the dispersion liquid is more likely to penetrate deep into the water-containing bulk material on a belt conveyer than the W/O type emulsion.

[0025] Further, as a result of studies by experiments conducted by the present inventors, it has been found that the dispersion liquid is more unlikely to cause clogging in the outlet or outlets in the tubular member, which will be described later, than the W/O type emulsion. From this result, it is considered that when the dispersion liquid is used, the polymer flocculant is more likely to be added uniformly to the water-containing bulk material than when the W/O type emulsion is used.

[0026] The dispersion liquid can be produced by, for example, dissolving a monomer for forming a polymer (polymer flocculant) and a polymer dispersant in an aqueous salt solution to perform a dispersion polymerization method. The dispersion liquid is preferably a dispersion liquid obtained by such a dispersion polymerization method and is more preferably a dispersion liquid containing, in an aqueous salt solution, a polymer flocculant and a polymer dispersant for dispersing the polymer flocculant. Examples of the polymer dispersant include, but not limited to, (co)polymers of anionic monomers such as (meth)acrylic acid, maleic acid, itaconic acid, acrylamide 2 methylpropanesulfonic acid, and styrenesulfonic acid, or salts thereof. Further, copolymers of any of the above described anionic monomers or the salts thereof with acrylamide, N-vinylformamide, N-vinylacetamide, N vinylpyrrolidone, N,N-dimethylacrylamide, acrylonitrile, diacetone acrylamide, and 2-hydroxyethyl (meth)acrylate, or the like, which is a nonionic monomer, can also be used. Besides, anion-modified polyvinyl alcohols, styrene/maleic anhydride copolymers, butene/maleic anhydride copolymers, or partially amidated products thereof can also be used.

[0027] Examples of the anion that forms a salt in the aqueous salt solution include halide ions, a sulfonate ion, a sulfite ion, a nitrate ion, a nitrite ion, and a phosphate ion. Examples of the cation that forms a salt include a sodium ion, a potassium ion, a magnesium ion, a calcium ion, and an ammonium ion. The aqueous salt solution is preferably an aqueous ammonium sulfate solution or an aqueous magnesium sulfate solution, and is more preferably an aqueous ammonium sulfate solution.

[0028] The polymer flocculant refers to a polymer compound that functions as a flocculant, and a water soluble polymer (including a copolymer) having such a function is suitably used. The polymer flocculant can contain any of an anionic structural unit derived from an anionic monomer, a cationic structural unit derived from a cationic monomer, and a nonionic structural unit derived from a nonion, and can contain one, or two or more of these. As the polymer flocculant, anionic polymer flocculants, cationic polymer flocculants, nonionic polymer flocculants, and amphoteric polymer flocculants can be used. One of these may be used singly, or two or more of these may be used together. Among these, the polymer flocculant is preferably an anionic polymer dispersant or a nonionic polymer dispersant, and is more preferably an anionic polymer flocculant.

[0029] Examples of the anionic monomer include (meth)acrylic acid, (meth)acrylic acid salts such as sodium (meth)acrylate, and 2-methylpropanesulfonic acid. Examples of the cationic monomer include dimethylaminoethyl (meth)acrylate, dimethylaminopropyl (meth)acrylate, and dimethylaminopropyl (meth)acrylamide, and quaternized products thereof. Examples of the quaternized products include acryloyloxyethyltrimethylammonium chloride and methacryloyloxyethyltrimethylammonium chloride. Examples of the nonionic monomer include (meth)acrylamide and N,N' dimethyl (meth)acrylamide.

[0030] Examples of a suitable polymer flocculant include a poly(meth)acrylic acid-based flocculant which is a polymer of a (meth)acrylic acid-based monomer, a poly(meth)acrylic acid ester-based flocculant which is a polymer of a (meth)acrylic acid ester-based monomer, a poly(meth)acrylamide-based flocculant which is a polymer of (meth)acrylamide, a polyalkylaminoalkyl (meth)acrylate quaternary salt-based flocculant which is a polymer of an alkylaminoalkyl (meth)acrylate-based monomer, and a polyvinyl amidine-based flocculant. In addition, examples of a suitable polymer flocculant include a copolymer-based flocculant containing a structural unit derived from one, or two or more monomers selected from the group consisting of a (meth)acrylic acid-based monomer, a (meth)acrylic acid ester-based monomer, (meth)acrylamide, and an alkylaminoalkyl (meth)acrylate-based monomer. Among these, the polymer flocculant is more preferably a copolymer-based flocculant containing an anionic structural unit derived from an anionic monomer and a structural unit derived from (meth)acrylamide.

[0031] As used herein, the term "(meth)acryl" means that it includes both of the terms, acryl and methacryl. In addition, the term "(meth)acryloyl" means that it includes both of the terms "acryloyl" and "methacryloyl."

Further, the "structural unit" means a monomer unit that forms a polymer flocculant (polymer). Examples of the "structural unit derived from a monomer" include a structural unit containing a single bond (-C-C-) as a result of cleavage of a polymerizable double bond (C=C) in the monomer.

[0032] Examples of the (meth)acrylic acid-based monomer include, but not limited to, (meth)acrylic acid and besides, metal salts of (meth)acrylic acid, such as sodium (meth)acrylate, potassium (meth)acrylate, and lithium (meth)acrylate; ammonium (meth)acrylate; and amine salts of (meth)acrylic acid. Hereinafter, such (meth)acrylic acid based monomers are sometimes referred to as "(meth)acrylic acid (salts)" including (meth)acrylic acid and salts thereof. In addition, examples of the (meth)acrylic acid ester-based monomer include, but not limited to, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate.

[0033] More suitable examples of the copolymer-based flocculant include a flocculant of a copolymer of (meth)acrylic acid or a (meth)acrylic acid salt, and (meth)acrylamide ((meth)acrylic acid (salt)/(meth)acrylamide copolymer); and a flocculant of a copolymer of (meth)acrylamide, (meth)acrylic acid or a salt thereof, and 2-acrylamide-2-methylpropanesulfonic acid or a salt thereof ((meth)acrylamide/(meth)acrylic acid (salt)/2 acrylamide-2-methylpropanesulfonic acid (salt) copolymer).

[0034] The copolymer-based flocculant may contain a structural unit derived from a monomer (additional monomer) other than the above-described monomers. Examples of the additional monomer include unsaturated dicarboxylic acids such as maleic acid, fumaric acid, and itaconic acid, and salts thereof; carboxylic anhydrides such as maleic anhydride and itaconic anhydrate; aromatic vinyl-based compounds such as styrene and a-methylstyrene; unsaturated sulfonic acids such as vinylsulfonic acid and styrene sulfonic acid, and salts thereof; vinyl acetate; acrylonitrile; and methacrylonitrile.

[00351 The weight average molecular weight (Mw) of the polymer flocculant is preferably 3000000 to 30000000, and more preferably 5000000 to 25000000. This weight average molecular weight can be measured by gel permeation chromatography (GPC).

[00361 The polymer flocculant preferably contains one, or two or more selected from the group consisting of a poly(meth)acrylic acid-based flocculant, a poly(meth)acrylic acid ester-based flocculant, a poly(meth)acrylamide-based flocculant, and a sodium (meth)acrylate/(meth)acrylamide copolymer-based flocculant. Among these, the dispersion liquid more preferably contains, as the polymer flocculant, at least one selected from the group consisting of a sodium (meth)acrylate/(meth)acrylamide copolymer (the above described sodium (meth)acrylate/(meth)acrylamide copolymer based flocculant), a polymer of acrylic acid or a salt thereof (the above-described poly(meth)acrylic acid-based flocculant), and an acrylamide polymer, and still more preferably contains a sodium acrylate/acrylamide copolymer.

[0037] As the dispersion liquid, a commercially available chemical solution containing a polymer flocculant in the form of dispersion in an aqueous salt solution can be used, and the commercially available chemical solution is preferably used as it is as an undiluted solution. It is often the case that such a commercially available chemical solution (dispersion liquid) has a polymer flocculant content of about 20% by mass. From these viewpoints, the polymer flocculant content in the dispersion liquid is preferably 10 to 40% by mass, more preferably 10 to 30% by mass, and still more preferably 15 to 25% by mass, based on the total mass of the dispersion liquid.

[00381 The amount of the dispersion liquid to be added to the water-containing bulk material, when expressed by a proportion in terms of the polymer flocculant in the dispersion liquid to be added, based on the total mass of the water-containing bulk material, is preferably 0.0001 to 0.1% by mass, more preferably 0.0002 to 0.02% by mass, and still more preferably 0.0005 to 0.012% by mass. The above described "total mass of the water-containing bulk material" refers to the sum of the mass of the solid content (bulk material) and the mass of water in the water containing bulk material to which the dispersion liquid is to be added. In addition, the proportion in terms of the polymer flocculant to be added, based on the total mass of the water-containing bulk material, is calculated by dividing the mass in terms of the polymer flocculant (active ingredient) in the dispersion liquid to be added by the total mass of the water-containing bulk material.

[0039] (Tubular Member) In the method for treating a water-containing bulk material of one embodiment of the present invention, a tubular member installed above a belt conveyor is used when the dispersion liquid is added to the water-containing bulk material. As this tubular member, a tubular member wherein an outlet or outlets that allow the dispersion liquid to flow out over the width direction of the belt conveyor are provided in the peripheral wall along the major axis direction is used. Hereinafter, description will be made on the tubular member with reference to the drawings.

[0040] Figure 1 is a schematic side view showing one example of a configuration of a tubular member 10 that can be used for the method for treating a water-containing bulk material of one embodiment of the present invention and that can be used for a flocculant adding apparatus of one embodiment of the present invention, which will be described later. Figure 2 is a partially enlarged diagram of a schematic plan view viewed from the front of outlets

13 of the tubular member 10 shown in Figure 1. Each of Figure 3A and Figure 3B is a diagram for describing an example of installing the tubular member 10 and is a schematic top view showing the tubular member 10 together with a belt conveyor 1, the schematic top view viewed from above the tubular member 10. Figure 4 is a schematic diagram showing one example of a configuration of a flocculant adding apparatus 100 of one embodiment of the present invention, which will be described later. Note that in the respective figures, the same reference signs are given to common constitutional units, and the description thereof may be omitted.

[0041] In the method for treating a water-containing bulk material of one embodiment of the present invention, the tubular member 10, wherein the outlets 13 that allow the dispersion liquid allowed to flow in an inside 10a of the tubular member 10 to flow out over a width direction X of the belt conveyor 1 are provided in a peripheral wall b along a major axis direction A, is used as shown in Figure 1 to Figure 4. Allowing the dispersion liquid to flow out over the width direction X of the belt conveyor 1 by the outlets 13 does not necessarily have to allow the dispersion liquid to flow out over the entire width in the width direction X. This is because a water-containing bulk material 2 is not necessarily mounted on the belt conveyor 1 over the entire width in the width direction X. Allowing the dispersion liquid to flow out from the outlets 13 is preferably performed in a width of approximately 50% or more, more preferably 60% or more, and still more preferably 70% or more, based on the entire width in the width direction X of the belt conveyor 1.

[0042] As shown in Figure 1, the tubular member 10 is a member formed into a tubular shape in which the longitudinal direction is the axial direction. Since the longitudinal direction of the tubular member 10 is the axial direction, this axis direction is referred to as the major axis direction A. As the material for the tubular member 10, for example, a polyvinyl chloride pipe; a lead pipe; a steel pipe; a stainless steel pipe; and resin or rubber blade hoses such as a polyvinyl chloride blade hose, a polyester blade hose, a polytetrafluoroethylene blade hose, a polyolefin-based resin blade hose, and a silicone rubber blade hose can suitably be used. Among these, the tubular member 10 is more preferably a polyvinyl chloride pipe.

[0043] In addition, the tubular member 10 has a tubular shape and therefore has an inside (space) 10a. In the inside 10a of the tubular member 10, the dispersion liquid flows. The dispersion liquid having flowed in the inside 10a of the tubular member 10 flows out from the outlets 13, which will be described later, and therefore the inside 10a of the tubular member 10 is also a flow channel of the dispersion liquid. The diameter (pipe inner diameter) of the inside 10a of the tubular member 10 is not particularly limited, but is preferably 10 to 500 mm, more preferably 20 to 50 mm, and still more preferably 20 to 50 mm.

[0044] The length of the tubular member 10 in the major axis direction A is preferably designed in such a way that the dispersion liquid that flows in the inside 10a of the tubular member 10 and flows out from the outlets 13 spreads over the width direction X of the belt conveyor 1. From this viewpoint, the length of the tubular member 10 in the major axis direction A is preferably 0.5 to 2 times, more preferably 0.6 to 1.5 times, and still more preferably 0.7 to 1.2 times, the width of the belt conveyor 1.

[0045] As shown in Figure 3A and Figure 3B, the tubular member 10 may be installed in such a way that the major axis direction A of the tubular member 10 faces the width direction X (the one end side and the other end side in the width direction X) of the belt conveyor 1 that conveys the water-containing bulk material 2.

Specifically, as shown in Figure 3B, the tubular member 10 may be provided in such a way that the major axis direction A of the tubular member 10 is oblique (non-parallel) with respect to the width direction X of the belt conveyor 1 (in other words, the tubular member 10 may be provided in such a way that the major axis direction A of the tubular member is oblique (non-vertical) with respect to the running direction Y of the belt conveyor 1). The tubular member 10 is preferably installed in such a way that the major axis direction A of the tubular member 10 is almost parallel with respect to the width direction X of the belt conveyor 1 (an angle formed by the major axis direction A of the tubular member 10 and the width direction X of the belt conveyor 1 falls within a range of 0° ± 100), as shown in Figure 3A.

[0046] As shown in Figure 4 showing a schematic configuration of the flocculant adding apparatus 100 which will be described later, the tubular member 10 is installed above the belt conveyor 1. On this occasion, in order to allow the dispersion liquid to flow out from the outlets 13 of the tubular member 10 and add the dispersion liquid to the water-containing bulk material 2 on the belt conveyor 1, the tubular member 10 can be installed in such a way that the outlets 13 face a mounting surface la of the belt conveyor 1. In addition, as for the installation height of the tubular member 10, the tubular member 10 is preferably installed at a position where height H from the mounting surface la of the belt conveyor 1 to the outlets 13 of the tubular member 10 is 10 to 300 cm (more preferably 10 to 250 cm, and still more preferably 10 to 200 cm) considering the height (thickness) of the water-containing bulk material 2 on the belt conveyor 1. However, the installation height of the tubular member 10 can be adjusted in such a way that the height from the highest point of the water-containing bulk material 2 to the outlets 13 of the tubular member 10 falls within the above- described range considering the height (thickness) of the water-containing bulk material 2 on the belt conveyor 1.

[0047] The tubular member 10 has the outlets 13 provided in the peripheral wall 10b along the major axis direction A. These outlets 13 are sites from which the dispersion liquid allowed to flow in the inside 10a of the tubular member 10 flows out. The outlets 13 are provided in the peripheral wall 10b of the tubular member 10 along the major axis direction A, and therefore, as described above, when the tubular member 10 is installed in the direction of intersecting (preferably, in the direction (width direction X) of orthogonally intersecting) the running direction Y of the belt conveyor 1 (see, Figure 3A and Figure 3B), thereby it is made possible to allow the dispersion liquid to flow out over the width direction X of the belt conveyor 1. The length of the outlets 13 along the major axis direction A, when expressed by the length from the edge on one end side (see, one end side inlet 14, which will be described later) to the edge on the other side (see, the other end side inlet 15, which will be described later) in the major axis direction A in the outlets 13, is preferably approximately 60 to approximately 100%, and more preferably approximately 70 to approximately %, of the length of the tubular member 10 in the major axis direction A.

[0048] As shown in Figure 1 and Figure 2, the outlets 13 are preferably formed by a plurality of outlet holes 13a provided in the peripheral wall 10b of the tubular member along the major axis direction A. Due to this, the dispersion liquid (polymer flocculant) is likely to be added more uniformly to the water-containing bulk material 2 present over the width direction X of the belt conveyor 1 (the direction orthogonal to the running direction Y of the belt conveyor 1). From this viewpoint, the addition of the dispersion liquid is preferably performed during driving the belt conveyor 1 (during running in the running direction Y) because the efficiency is higher. The addition of the dispersion liquid may be performed during stopping the belt conveyor 1 as long as it is performed to the water-containing bulk material 2 on the belt conveyor 1. In addition, a plurality of the outlet holes 13a is more preferably provided in such a way that the intervals between the respective outlet holes 13 are equal and is still more preferably formed in such a way that it is possible to allow the dispersion liquid to flow out in a straight rod-like shape from each outlet 13a.

[0049] In the tubular member 10, an example where 12 outlet holes 13a are provided is shown in Figure 1 and Figure 2, but the number and diameter of the outlet holes 13a can appropriately be determined according to, for example, the pipe inner diameter and length of the tubular member 10, and the flow rate and flow pressure of the dispersion liquid. As one aspect, the number of the outlet holes 13a is preferably 8 to 18 and more preferably 10 to 15. Further, in this case, the diameter of the outlet holes 13a is preferably 1 to 5 mm, and is, from the viewpoint of suppression of clogging of the dispersion liquid in the outlet holes 13a, more preferably 1.5 mm or larger, and still more preferably 2 mm or larger. On the other hand, from the viewpoint of equalization of (suppression of variation in) the amount of the dispersion liquid flowing out from each outlet hole 13a, the diameter of the outlet holes 13a is more preferably 4.5 mm or smaller, and still more preferably 4 mm or smaller.

[0050] The tubular member 10 may be formed in such a way that the dispersion liquid 10a can flow in the inside a, and the tubular member 10 including an inlet to allow the dispersion liquid to flow in the inside 10a can suitably be used. The inlet in the tubular member 10 may be provided on any one of the one end side and the other end side in the major axis direction A of the tubular member 10, or may be provided on both sides. In addition, a tubular member in which both ends in the major axis direction A are closed may be used, and in that case, the inlet for the dispersion liquid may be provided at a part (for example, the central part) in the major axis direction in the peripheral wall, or the inlet may be provided at plural parts in the major axis direction in the peripheral wall.

[0051] As shown in Figure 1 and Figure 2, the tubular member 10 preferably includes a one end side inlet 14 and the other end side inlet 15 for allowing the dispersion liquid to flow in the inside 10a at one end side and the other end side respectively in the major axis direction A. In this case, the dispersion liquid is preferably allowed to flow in the inside 10a from both of the one end side inlet 14 and the other end side inlet 15 in the tubular member 10, and the flow pressure of the dispersion liquid into the respective inlets 14, 15 is more preferably constant (equal). Due to these configurations, the amount of the dispersion liquid flowing out from the outlets 13 (a plurality of outlet holes 13a) provided in the peripheral wall 10b along the major axis direction A is likely to be equalized because occurrence of the differences in the amount between different positions of the outlets 13 (outlet holes 13a) in the major axis direction A is suppressed. For that reason, the dispersion liquid (polymer flocculant) is likely to be added more uniformly to the water-containing bulk material 2 present over the width direction X of the belt conveyor 1 (the direction orthogonal to the running direction Y of the belt conveyor 1).

[0052] The above-described tubular member 10 includes outlets 13 formed by a plurality of outlet holes 13a provided in the peripheral wall 10b along the major axis direction A, but the configuration of the outlets 13 in the tubular member 10 is not limited to a plurality of the outlet holes 13a. This is because, for example, as for the shape, size, number, position, and the like of the outlets of the tubular member, the adequate configuration of the outlet or outlets may change depending on the length, pipe inner diameter, and the like of the tubular member, and various factors such as the flow rate, flow pressure, and the like in allowing the dispersion liquid to flow in the inside of the tubular member. By adjusting the above described various factors, the adequate configuration of the outlet or outlets can be determined.

[00531 As a modification example of the tubular member, an outlet 23, such as one in a tubular member 20 shown in Figure 5, may be formed by a slit 23a provided in a peripheral wall 20b of the tubular member 20 along the major axis direction A. Due to this, it is possible to allow the dispersion liquid to flow out in a straight curtain-like shape from the slit 23a and the dispersion liquid (polymer flocculant) is likely to be added more uniformly to the water-containing bulk material 2 present over the width direction X of the belt conveyor 1.

[0054] The width of the slit 23a in the tubular member can appropriately be determined according to, for example, the length and pipe inner diameter of the tubular member 20, and the flow rate, flow pressure, and the like of the dispersion liquid, but is preferably 0.1 to 1 mm as one aspect. In this case, the width of the slit 23a is more preferably 0.2 mm or more from the viewpoint of suppression of clogging of the dispersion liquid in the slit 23a, and is, on the other hand, more preferably 0.8 mm or less, and still more preferably 0.5 mm or smaller, from the viewpoint of equalization of the amount of the dispersion liquid flowing out from the entire length of the slit 23a.

[00551 Further, as another modification example of the tubular member, outlets 33, such as those in a tubular member 30 shown in Figure 6, may be formed by a plurality of nozzles 33a provided in a peripheral wall 30b of the tubular member 30 along the major axis direction A. Due to this, it is possible to allow the dispersion liquid to flow out in a straight rod-like shape from the respective nozzle 33a (the tip openings of the respective nozzle 33a) and the dispersion liquid (polymer flocculant) is likely to be added more uniformly to the water-containing bulk material 2 present over the width direction X of the belt conveyor 1.

[00561 A plurality of the nozzles 33a in the tubular member 30 is preferably provided in such a way that the intervals between the respective nozzles 33a are equal. The length, number, tip opening diameter, and the like of the nozzles 33a that extend toward the conveyor 1 side can appropriately be determined according to, for example, the length, pipe inner diameter, and the like of the tubular member 30, and the flow rate, flow pressure, and the like in allowing the dispersion liquid to flow in the inside of the tubular member 30. As one aspect, the length of the nozzles 33a is preferably 1 to 30 cm, more preferably 2 to cm, and still more preferably 5 to 20 cm. Note that the size of the tip diameter of the nozzles 33a and the installation height of the tubular member 30 including the nozzles 33a can be described by replacing the outlet holes 13a (outlets 13) in the above description about the corresponding items of the tubular member 10 with the tip openings of the nozzles 33a.

[0057] (Pump) As shown in Figure 4, when the dispersion liquid is added to the water-containing bulk material 2 on the belt conveyor 1 from the outlets 13 of the tubular member 10, a pump 52 that transfers the dispersion liquid into the tubular member 10 is preferably used.

[00581 As the pump 52, a pump capable of transferring the dispersion liquid into the tubular member 10 by the action of pressure can be used. Examples of the pump 52 include non-positive displacement (turbo) pumps such as a centrifugal pump, a diffuser pump, a mixed flow pump, and an axial flow pump; and positive displacement pumps such as a diaphragm pump, a piston pump, a plunger pump, a gear pump, a screw pump, and a vane pump. Among these, the pump 52 is preferably a screw pump, and from the viewpoint that clogging of the dispersion liquid is more likely to be suppressed and thereby the dispersion liquid is likely to be added to the water-containing bulk material more uniformly, the pump 52 is still more preferably a uniaxial eccentric screw pump (Mohno Pump).

[00591 Note that piping, a joint, or the like can be used for connection or the like of the pump 52 and the tubular member 10, and these will be given in the description of a flocculant adding apparatus below.

[00601 In the method for treating a water-containing bulk material of one embodiment of the present invention, which is described above in detail, the dispersion liquid containing a polymer flocculant in the form of dispersion in an aqueous salt solution, and a particular tubular member are used. Thereby, a method by which even when a polymer flocculant is continuously added to a water containing bulk material being conveyed with a belt conveyor, the polymer flocculant is likely to be added more uniformly to the water-containing bulk material using simpler equipment such as a particular tubular member can be provided. It is considered that, as described above, following conceivable characteristics of the dispersion liquid contribute significantly to this: the characteristic such that the dispersion liquid is unlikely to cause clogging in the openings of the members which are used for the addition of the flocculant; and the characteristic such that the dispersion liquid is likely to be dissolved into water in the water-containing bulk material and is thereby likely to penetrate into the water-containing bulk material and disperse the polymer flocculant in the water-containing bulk material, because the dispersion liquid contains an aqueous salt solution as a dispersion medium.

[0061] Accordingly, examples of the method for treating a water-containing bulk material of another embodiment of the present invention include a method for treating a water-containing bulk material including adding a dispersion liquid containing a polymer flocculant in the form of dispersion in an aqueous salt solution to a water containing bulk material. According to this method, a method by which, for example, even when a polymer flocculant is continuously added to a water-containing bulk material being conveyed with a belt conveyor, the polymer flocculant is likely to be added more uniformly to the water-containing bulk material using simpler equipment can also be provided by the above-described characteristics of the dispersion liquid. As the simple equipment, any of the above-described tubular members or the like may be used, and another type of equipment other than those may be used. In this method, a dispersion liquid containing a polymer flocculant in the form of dispersion in an aqueous ammonium sulfate solution is preferably used. Further, the polymer flocculant in the dispersion liquid is more preferably a copolymer-based flocculant containing a structural unit derived from an anionic monomer and a structural unit derived from (meth)acrylamide, and is still more preferably a (meth)acrylic acid (salt)/(meth)acrylamide copolymer. As just described, any of preferred configurations described in the above-described method for treating a water containing bulk material of the above-described embodiment can also be adopted in this method.

[0062] <Flocculant Adding Apparatus> A flocculant adding apparatus of one embodiment of the present invention (hereinafter, sometimes simply referred to as "flocculant adding apparatus") is an apparatus that adds a flocculant to a water-containing bulk material being conveyed with a belt conveyor. This flocculant adding apparatus can suitably be utilized for the above-described method for treating a water-containing bulk material of one embodiment of the present invention. Hereinafter, description will be made on the flocculant adding apparatus with reference to Figure 4. Figure 4 is a schematic diagram of a flocculant adding apparatus 100 including the above-described tubular member 10. Note that, for reference, in Figure 4, the direction in which the dispersion liquid flows is shown by a one-directional arrow.

[00631 The flocculant adding apparatus 100 includes: a tank 51 that stores the above-described dispersion liquid; a tubular member 10 that is installed above a belt conveyor 1; and a pump 52 that transfers the dispersion liquid into the tubular member 10 from the tank 51. Although showing the dispersion liquid is omitted in the figure, the dispersion liquid containing a polymer flocculant in the form of dispersion in an aqueous salt solution is stored in the tank 51, as described above.

[0064] As described above, in the tubular member 10, the outlets 13 that allow the dispersion liquid allowed to flow in the inside 10a to flow out over the width direction X of the belt conveyor 1 are provided in the peripheral wall 10b along the major axis direction A, as shown in Figure 1 and Figure 2. In addition, the outlets 13 are formed by a plurality of outlet holes 13a provided at equal intervals in the peripheral wall 10b of the tubular member along the major axis direction A. Further, the tubular member 10 includes a one end side inlet 14 and the other end side inlet 15 for allowing the dispersion liquid to flow in the inside at one end side and the other end side respectively in the major axis direction A. For example, in the flocculant adding apparatus 100, any of the above described tubular members 20, 30 may be used in place of the tubular member 10, and a tubular member in which the number, diameter, shape, and the like of the outlets 13 (outlet holes 13a) in the tubular member 10, and the number, position, and the like of the inlets 14, 15 are changed may be used.

[00651 Any of the above-described various types of pumps can also be used as the pump 52 in the flocculant adding apparatus 100, and among those, the pump 52 is preferably a screw pump and is more preferably a uniaxial eccentric screw pump (Mohno Pump).

[00661 The flocculant adding apparatus 100 can include: first piping 61 that connects the tank 51 and the pump 52; and second piping 62 that connects the pump 52 and the tubular member 10. By the function of the pump 52, the dispersion liquid stored in the tank 51 is sucked through the first piping 61 to the pump 52 and is supplied to a supply port 52a of the pump 52. A joint 71 can be used for connection of the first piping 61 and the supply port 52a of the pump 52, and further, a valve 81 may be provided at the joint 71. Due to the valve 81, the flow rate and pressure of the dispersion liquid to be supplied to the pump 52 can be adjusted, and supplying the dispersion liquid and stopping the supply can be switched.

[0067] Further, by the function of the pump 52, the dispersion liquid supplied from the tank 51 is discharged from a discharge port 52b of the pump 52 and is transferred into the tubular member 10 through the second piping 62 connected to the discharge port 52b of the pump 52. A joint 72 can be used for connection of the second piping 62 and the ejection port 52b of the pump 52, and further, a valve 82 may be provided at the joint 72. Due to the valve 82, the flow rate and pressure of the dispersion liquid to be discharged from the pump 52 can be adjusted, and discharging the dispersion liquid and stopping the discharge can be switched.

[00681 Since the flocculant adding apparatus 100 includes the tubular member 10 having the one end side inlet 14 and the other end side inlet 15, the second piping 62 that connects the pump 52 and the tubular member 10 is branched into first branch piping 64 and second branch piping 65 through a three-way joint 73. The first branch piping 64 is connected to the one end side inlet 14 of the tubular member 10 by the joint 74. The second branch piping 65 is connected to the other end side inlet 15 of the tubular member 10 by the joint 75. A valve 83, 84, 85 may be provided at the three-way joint 73, the joint 74 which is on the one end side inlet 14 side, and the joint which is on the other end side inlet 15 side, respectively. Due to the valves 83, 84, 85, the flow rate and pressure of the dispersion liquid that is allowed to flow into the tubular member 10 can be adjusted, and allowing the dispersion liquid to flow in and the stopping thereof can be switched.

[00691 Note that for the above-described respective piping 61, 62, 64, 65, any of pipes, hoses, tubes, and the like of materials given in the above description of the tubular member 10 can be used, and among those, polyvinyl chloride pipes and various types of blade hoses are preferable. In addition, for the above-described joints 71 to 75, pipe joints and hose joints can be used.

[0070] With the flocculant adding apparatus 100, the above-described method for treating a water-containing bulk material of one embodiment of the present invention can be carried out by, for example, starting the pump 52; adjusting the flow rate, pressure, and the like in the pump 52 regarding the supply and discharge of the dispersion liquid; and adjusting the flow rate, pressure, and the like of the dispersion liquid that is allowed to flow into the tubular member 10.

[0071] Accordingly, by using the flocculant adding apparatus of one embodiment of the present invention, clogging in the outlets of the tubular member is suppressed, and the polymer flocculant can be added in a state where the polymer flocculant is likely to penetrate into the water-containing bulk material present over the width direction of the belt conveyer. Therefore, even when this flocculant adding apparatus is operated continuously for a long time, or even if mixing of the water-containing bulk material and the polymer flocculant is not sufficiently secured owing to the circumstances of the equipment to which a belt conveyor is installed, the polymer flocculant is likely to be added more uniformly to the water-containing bulk material.

[0072] Thus, the flocculant adding apparatus can suitably be used in an aspect such that the flocculant adding apparatus is installed in the vicinity of equipment including a belt conveyor for conveying a water-containing bulk material when the water-containing bulk material is loaded onto a ship or the like at a mining site; equipment including a belt conveyor for loading and conveying a water-containing bulk material that have been transported outside the mining site by ship or the like; equipment including a belt conveyor for conveying a water-containing bulk material to storage sites, processing facilities, usage facilities and the like inside and outside the mining site; or in an aspect such that the flocculant adding apparatus is installed to such equipment. As a result, effects such as facilitating loading operation for a water containing bulk material onto a ship or the like, suppression of collapse of the loaded water-containing bulk material, suppression of occurrence of a loading obstacle in loading the water-containing bulk material onto a belt conveyor or the like, suppression of occurrence of a conveyance obstacle caused by a belt conveyor or the like, suppression of occurrence of collapse of a conveyed and stacked water-containing bulk material, and suppression of dust generation by wind from a stacked water-containing bulk material can be expected.

[0073] As described above, in the techniques on the method for treating a water-containing bulk material of one embodiment of the present invention and the flocculant adding apparatus of one embodiment of the present invention, the following constitution and configuration can be adopted.

[1] A method for treating a water-containing bulk material, comprising adding a flocculant to the water containing bulk material being conveyed with a belt conveyor, the method comprising: using a dispersion liquid comprising, as the flocculant, a polymer flocculant in a form of dispersion in an aqueous salt solution; using a tubular member wherein an outlet or outlets that allow the dispersion liquid to flow out over a width direction of the belt conveyor are provided in a peripheral wall along a major axis direction, the tubular member installed above the belt conveyor; and adding the dispersion liquid to the water-containing bulk material on the belt conveyor from the outlet or outlets of the tubular member.

[2] The method for treating a water-containing bulk material according to [1], comprising transferring the dispersion liquid into the tubular member using a pump, and adding the dispersion liquid allowed to flow in an inside of the tubular member to the water-containing bulk material on the belt conveyor from the outlet or outlets in adding the dispersion liquid.

[3] The method for treating a water-containing bulk material according to [2], comprising using a uniaxial eccentric screw pump as the pump.

[4] The method for treating a water-containing bulk material according to any one of [1] to [3], wherein the outlet or outlets are formed by a plurality of outlet holes provided in the peripheral wall of the tubular member along the major axis direction.

[5] The method for treating a water-containing bulk material according to any one of [1] to [4], wherein the tubular member comprises a one end side inlet and the other end side inlet for allowing the dispersion liquid to flow in an inside of the tubular member at one end side and the other end side respectively in the major axis direction, and the method comprises allowing the dispersion liquid to flow in the inside from both of the one end side inlet and the other end side inlet in the tubular member.

[6] The method for treating a water-containing bulk material according to any one of [1] to [5], wherein the polymer flocculant is a copolymer-based flocculant comprising an anionic structural unit derived from an anionic monomer and a structural unit derived from (meth)acrylamide.

[7] The method for treating a water-containing bulk material according to [6], wherein the polymer flocculant is a copolymer of (meth)acrylic acid or a (meth)acrylic acid salt, and (meth)acrylamide.

[8] The method for treating a water-containing bulk material according to any one of [1] to [7], wherein the aqueous salt solution is an aqueous ammonium sulfate solution.

[9] A method for treating a water-containing bulk material, comprising adding a dispersion liquid comprising a polymer flocculant in a form of dispersion in an aqueous salt solution to the water-containing bulk material.

[10] A flocculant adding apparatus that adds a flocculant to a water-containing bulk material being conveyed with a belt conveyor, the apparatus comprising: a tank that stores a dispersion liquid comprising, as the flocculant, a polymer flocculant in a form of dispersion in an aqueous salt solution; a tubular member that is installed above the belt conveyor, wherein an outlet or outlets that allow the dispersion liquid allowed to flow in an inside of the tubular member to flow out over a width direction of the belt conveyor are provided in a peripheral wall along a major axis direction; and a pump that transfers the dispersion liquid into the tubular member from the tank.

[11] The flocculant adding apparatus according to

[10], wherein the outlet or outlets are formed by a plurality of outlet holes provided in the peripheral wall of the tubular member along the major axis direction.

[12] The flocculant adding apparatus according to

[10] or [11], wherein the tubular member comprises a one end side inlet and the other end side inlet for allowing the dispersion liquid to flow in the inside at one end side and the other end side respectively in the major axis direction.

[13] The flocculant adding apparatus according to any one of [10] to [12], comprising a uniaxial eccentric screw pump as the pump.

Examples

[0074] Hereinafter, the effects and the like of the method for treating a water-containing bulk material of one embodiment of the present invention will more specifically be described giving Test Examples.

[0075] <Test Example 1> In Test Example 1, dispersion liquids each containing a polymer flocculant in the form of dispersion in an aqueous salt solution and W/O type emulsions each containing a polymer flocculant in the form of emulsion were used to conduct tests for ascertaining differences in effects caused by the dispersion liquids and the W/O type emulsions.

[0076] Minas-Rio ore that is an iron ore having a grain size of 5 mm or smaller as a result of sieving and having a water content of 11.2% by mass was used as a water-containing bulk material. In the tests for checking fluidity, which will be described later, water was added to this water-containing bulk material to adjust the water content to 15% by mass.

[0077] In Test Example 1, the following agents A to F were each used as a chemical solution to be added to the water-containing bulk material.

Agent A: a dispersion liquid (trade name "NS Dry 709L," manufactured by NIPPON STEEL Eco-Tech Corporation) containing 20% by mass of a sodium acrylate/acrylamide copolymer, which is an anionic polymer flocculant, in an aqueous ammonium sulfate solution Agent B: a dispersion liquid containing 20% by mass of an acryloyloxyethyltrimethylammonium chloride/acrylamide copolymer, which is a cationic polymer flocculant, in an aqueous salt solution Agent C: a dispersion liquid containing 20% by mass of an acrylamide polymer, which is a nonionic polymer flocculant, in an aqueous salt solution Agent D: a W/O type emulsion containing 40% by mass of a sodium acrylate/acrylamide copolymer, which is an anionic polymer flocculant Agent E: a W/O type emulsion containing 40% by mass of an acryloyloxyethyltrimethylammonium chloride/acrylamide copolymer, which is a cationic polymer flocculant Agent F: a W/O type emulsion containing 40% by mass of an acrylamide polymer, which is a nonionic polymer flocculant

[0078] Water was added to 500 g of the Minas-Rio ore to adjust the water content to 15% by mass. In a 1 L volume plastic bottle, the Minas-Rio ore having a water content adjusted to 15% by mass and the chemical solution described above were placed, and then the plastic bottle was turned upside down 5 times to perform upside-down stirring on the resultant mixture (turning the plastic bottle upside down corresponds to one upside-down stirring), and thus a mixed sample of the water-containing Minas-Rio ore and the chemical solution was prepared. The amount of the chemical solution added, based on the amount of the water-containing Minas-Rio ore, was as described in "Proportion of chemical solution added to water-containing bulk material" shown in Table 1 below.

[0079] On the other hand, a test tank, which is a rectangular parallelepiped tank having inside dimensions of a width (depth) of 200 mm, a length of 400 mm, and a height of 100 mm, and having an opening at one end in the height direction, and in which silica sand for slip prevention was spread all over the bottom surface and fixed, was prepared. A plastic cylindrical member without a bottom, having inside dimensions of an inner diameter of 60 mm and a height of 100 mm, was placed near the center of the bottom surface of this test tank, and then the cylindrical member was fully filled with the mixed sample prepared up to its height. Subsequently, the cylindrical member was pulled up, and the degree of collapse of the mixed sample which had a columnar shape by having been filled in the cylindrical member was evaluated for the mixed sample left at the bottom surface of the test tank when the cylindrical member was pulled up. Specifically, the maximum length in the diameter direction of the mixed sample left in the test tank after the cylindrical member was pulled up (an x value; the length in the horizontal direction in the test tank) and the maximum height of the mixed sample left (a y value; the height in the vertical direction in the test tank) were measured. When the x value of the mixed sample left is closer to the original inner diameter (60 mm) of the cylindrical member and is smaller, and when the y value of the mixed sample left is closer to the original height (100 mm) of the cylindrical member and is larger, such x and y values indicate that the mixed sample left has a shape closer to the original columnar shape formed by the mixed sample which had been present in the cylindrical member, and indicate that the fluidity of the mixed sample is lowered.

[00801 Results of the test example 1 using the above described chemical solutions are shown in Table 1. Note that in the table, results of a blank test in which the same test was conducted without using a chemical solution are also shown together.

-0 0 Lf) C"] CD L H CD Cf 0O 0 CDLCD

H a) Lf) C\1 Ln Lf) CD C

CD CDO) Q CD C

CO ~C K( CO

CD C

COD CO>

-H CO

0~

~I~u 0 0)" CO~~ -H-0 f

-- H

00 CO1

5 HU)-0C A

0 u 0) -(P F 0 -1 CO -H CO 0CC

-H > H CO H C

CO -H CO]I -H -Hw 0 0 -0 CO CO

CO11: Q, -H A 0-H) Q w Q -0 CD co -(I -H -o c -] - w w ~ -~~ FAQ I HICO : IfL 0

[0082] From the results of the test example 1, it was ascertained that the dispersion liquids are more likely to lower the fluidity of the water-containing bulk material than the W/O type emulsions in the case where the mixing condition with the water-containing bulk material is calm. Further, it was ascertained that regarding the type of the polymer flocculant, anionic polymer flocculant is more likely to lower the fluidity of the water-containing bulk material than the cationic and nonionic polymer flocculants.

[0083] <Test Example 2> In Test Example 2, the dispersion liquid (agent A) used in Test Example 1 was used, the amount of the dispersion liquid added was changed in a range of 0.0020 to 0.040% by mass as the amount of the polymer flocculant based on the total mass of the water-containing bulk material to conduct the same tests for evaluating the fluidity as in Test Example 1. As for the water-containing bulk material too, the same one as used in Test Example 1 was used.

[0084] Results of Test Example 2 are shown in Table 2. Note that in Table 2, results of a blank test in which the same test was conducted without using a chemical solution are also shown together.

CD CD, -H

C -Q0 CC -HD

-H ( H CC)

0DQ

CDi 4- n-D

D 0 0 C CD -H

CDoCO

CH CO C) Q0

vHC) I C- vH

co C)

C))

a)) -HO

0 - -H

0C

5H Q~a) (fl I~C Ih 0) -P4) ! 0 0-4 f

~~~c 0 >1d ( v- ~ ~~ 5 4-Q On~- EH U HH

[00861 From the results of Test Example 2, it was ascertained that the amount of the polymer flocculant to be added is enough when it is about 0.0020 to about 0.040% by mass based on the total mass of the water-containing bulk material and that in order to perform a more stable and sufficient treatment considering economic efficiency, the amount of the polymer flocculant to be added may be set to, for example, 0.002 to 0.02% by mass.

[0087] <Test Example 3> In Test Example 3, comparison was made on the likelihood of clogging of the polymer flocculant due to the differences of the outlet holes of flocculant addition apparatuses. As the chemical solution containing a polymer flocculant, each of the dispersion liquid (agent A) and the W/O type emulsion (agent D), which were used in Test Example 1, was used. In addition, as the flocculant adding apparatus, each of testing apparatuses assembled in such a way that each of the members having different configurations of the shape or the like of the outlet holes (the members described by the following conditions A to E) was connected to the joint 73 in the flocculant adding apparatus 100 shown in Figure 4 was used. The flow-out situation of the polymer flocculant from the outlet holes of each member was observed using these testing apparatuses. When sustainable flow-out of the polymer flocculant was recognized, continuous operation for a long time was conducted to perform visual evaluation on the relationship between the member and the flow-out situation and evaluation of the flow-out speed by measurement of the amount of the polymer flocculant that flowed out.

[00881 Condition A: A shower head (having outlets that allow the dispersion liquid to flow out like a shower, the outlets each having a hole diameter of about 0.5 mm) was used as the member. Condition B: High-viscous fluid atomizing nozzles (large type) manufactured by KYORITSU GOKIN Co., Ltd. was used as the member, expecting mist-like flow-out. Condition Cl: A polyvinyl chloride pipe which has a length of 1 m (assuming the width of the belt conveyor), a pipe inner diameter of 25 mm, and an opening at both ends and which has outlets in the peripheral wall of the pipe along the major axis direction (1-m length direction), the outlets being such that they are formed by 5 holes each having a hole diameter of 5 mm at equal intervals, was used as the member (see, the tubular member 10 shown in Figure 1). Condition C2: A member which is the same one as the polyvinyl chloride pipe used in the condition Cl except that the number of holes is 8 and the hole diameter of each hole is 4 mm was used. Condition C3: A member which is the same one as the polyvinyl chloride pipe used for the condition Cl except that the number of holes is 12 and the hole diameter of each hole is 3 mm was used. Condition D: A member in which, as a nozzle, a rod shaped vinyl chloride pipe having a pipe length of 50 mm and a pipe inner diameter of 3 mm is connected to each hole in the polyvinylchloride pipe used in the condition C3 was used (see, the tubular member 30 shown in Figure 6). Condition E: A polyvinyl chloride pipe having a 0.5 mm-wide slit parallel to the major axis direction, a pipe length of 1 m, and an inner diameter of 25 mm was used as the member (see, the tubular member 20 shown in Figure 5). Note that in the conditions A and B, the chemical solution (agent A or agent D) was allowed to flow in from one inlet, and in the conditions other than the conditions A and B, each member was used according to an aspect of allowing the dispersion liquid to flow in from both openings (the one end side inlet and the other end side inlet) in each member (tubular member), and each testing apparatus was configured to match such an aspect.

[00891 In the above-described testing apparatuses, the flow rate of the polymer flocculant supplied was set to a condition of 2.5 L/min using Mohno Pump ("NY-20," manufactured by HEISHIN Ltd.) to conduct continuous circulating operation tests for 72 hours. In these tests, the extent of clogging (degree of blocking) in the outlets and the uniformity of the addition at the time of starting the tests were evaluated by checking the states of the outlets of each member with the lapse of time. Results are shown in Table 3.

o o o om o o o C C C C -~ ~ 0- 0- - - - - 0 e r *o* r r o r o o

o 4< 4< 4< 4

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[0091] From the results of Test Example 3, it was found that the dispersion liquid (agent A) is more unlikely to cause clogging in the outlets in the tubular members than the W/O type emulsion (agent D). From these results of Test Example 3 and the above-described results of Test Example 1, it was ascertained that when the dispersion liquids are used, the polymer flocculant is more likely to be added to the water-containing bulk material uniformly for a long time than when the W/O type emulsions are used. Note that there is a possibility that the above-described various conditions are changed according to the site, facility, situation, and the like in which the flocculant addition apparatuses are used, and thereby a suitable configuration of the member can be changed.

[0092] <Test Example 4> In Test Example 4, the members which are the same as those used in the conditions Cl to C3 in Test Example 3 were used to investigate the influences of the differences in the number and diameter of the outlet holes of the tubular members under a predetermined condition on the balance of the amount of the dispersion liquid flowing out from each outlet hole. The dispersion liquids and the water-containing bulk material which are the same as those used in Test Example 1 were used.

[0093] Specifically, a polyvinyl chloride pipe having a length of 1 m, which assumes the width of the belt conveyor, and having a pipe inner diameter of 25 mm was used for all the tubular members, and each tubular member in which the outlet holes are provided in the peripheral wall of the polyvinyl chloride pipe along the major axis direction (1-m length direction) according to the number and diameter of outlet holes shown in Table 4 below at equal intervals was used. In addition, any of the tubular members was used according to an aspect that the dispersion liquid was allowed to flow in from both end openings (the one end side inlet and the other end side inlet).

[0094]

Table 4

Tubular member used in Test Example 4 Condition Cl Condition C2 Condition C3 Number of outlet holes 5 8 12 Diameter of outlet holes (mm) 5 4 3

[0095] The same testing apparatus as used in Test Example 2 was used, and the amount (L/min) of the dispersion liquid flowing out from each outlet hole of each tubular member was measured 1 hour after the start of the circulating operation test setting the flow rate of the dispersion liquid supplied to 2.5 L/min. The measurement of the flow-out amount was conducted by receiving the liquid flowed out from each hole with a measuring cylinder for 1 minute and reading the scale on the measuring cylinder. Results of this measurement are shown in Table 5. The numerical value of "Hole No." shown in Table 5 is the number given to the outlet hole in order from the nearest outlet hole to the one end side inlet (see, for example, the reference sign 14 in Figure 1) for a plurality of outlet holes in the tubular member used in each Test Example.

0 o

C)

z

C)

z

C)

z C 0

0) C

0 0

0) C

0 0

.00

z) z

0 0 0 0

o z0 z

o o C

o o 0

C o o C

o o a

C D CD

[0097] In the condition C1, a maximum difference of about 0.20 L/min in the amount of the dispersion liquid flowing out from each outlet hole (hole Nos. 1 to 5) was observed. In the condition C2, a maximum difference of about 0.10 L/min in the amount of the dispersion liquid flowing out from each outlet hole (hole Nos. 1 to 8) was observed. In the condition C3, the amount of the dispersion liquid flowing out from each outlet hole (hole Nos. 1 to 12) was uniform, and the condition C3 gave excellent balance of the flow-out amount. From the above results, it was ascertained that under the conditions adopted in Test Example 4 and including: the conditions of the material, length, pipe inner diameter, and the like of the tubular members used in Test Example 4; the type and operation conditions of the used pump; the conditions such as the material, length, and pipe inner diameter of the piping used for the testing apparatuses; and the like, the tubular member used in the condition C3 was the most suitable. Note that there is a possibility that the above described various conditions are changed according to the site, facility, situation, and the like in which the flocculant addition apparatuses are used, and thereby a suitable configuration of the member can be changed.

[0098] <Test Example 5> In a usage facility where a belt conveyor (having a width of 1 m) that actually conveys an iron ore was installed, the same testing apparatus (flocculant adding apparatus) as used in the above-described condition C3 including the tubular member was installed. As for the installation height of the tubular member, the height from the mounting surface of the belt conveyor to the outlet holes in the tubular member was set to 100 cm. In addition, the installation position of the tubular member with respect to the running direction of the belt conveyor was set to a position at about 100 cm from the starting position of the belt conveyor (the position where the iron ore was mounted). The belt conveyor was configured in such a way that 5 conveyor parts are connected with connection parts (junction sites; 4 in total) interposed therebetween, and the difference in height between the connection parts was about 150 cm. Carajas ore powder having a water content of 10% by mass or more was used as the iron ore, and the dispersion liquid (agent A) used in Test Example 1 was used as the chemical solution to be added to this Carajas ore powder.

[00991 At the starting position on the mounting surface of the belt conveyor, 500 t of the Carajas ore powder was loaded under a condition of an ore loading of 2,000 to 3,000 t/hour. In addition, the Mohno Pump in the testing apparatus was driven setting the conditions in such a way that 50 kg of the dispersion liquid was added to 500 t of the Carajas ore powder. In this way, the dispersion liquid was added over the width direction of the belt conveyor from the outlets (respective outlet holes) of the tubular member to the water-containing Carajas ore powder which was being transferred with the belt conveyor. Then, the Carajas ore powder to which the dispersion liquid had been added was removed at the end point of the belt conveyor and was then stacked on the yard, and the radius, r value (m), of the bottom of the stacked Carajas ore powder having an approximately conical shape, and the height, z value (m) of the stacked Carajas ore powder were measured and recorded. Results of this test are shown in Table 6. In Table 6, results of a blank test in which the same test was conducted without using the dispersion liquid are also shown together.

[0100]

Table 6

Blank test Test Example 5 Chemical solution used Not used Agent A (dispersion liquid)

Proportion of chemical solution added to water-containing Caraj - 0.01 as ore powder (% by mass)

Proportion in terms of polymer flocculant added to water- 0.002 containing Carajas ore powder (% by mass)

Radius of bottom of stacked water-containing Carajas ore 7.5 3.5 powder, r value (m)

Height of stacked water containing Carajas ore powder, 4.5 5.0 z value (m)

[0101] From the results of Test Example 5, it was ascertained in the actual field that due to the method for treating a water-containing bulk material using the dispersion liquid and the flocculant adding apparatus including a particular tubular member and the like, spread of the bottom of the stacked water-containing Carajas ore powder is suppressed and the height of the stacked water containing Carajas ore powder is likely to be retained.

[0102] Further, the same test as Test Example 5 was conducted (Comparative Example 5) except that the dispersion liquid was changed to the W/O type emulsion (agent D) used in Test Example 1. As a result, in Comparative Example 5, clogging was ascertained after the completion of the test in 2 outlet holes out of 12 outlet holes in the tubular member, but in Test Example 5 where the dispersion liquid (agent A) was used, clogging of the outlet holes was not ascertained. In addition, in Test Example 5 where the dispersion liquid was used, the effect of about the same extent as in Comparative Example 5 was obtained at about half the proportion in terms of the polymer flocculant added to the water-containing Carajas ore powder as compared to the proportion in terms of the polymer flocculant added in Comparative Example 5. From this result, it is considered that the dispersion liquid is more likely to penetrate into the water-containing bulk material and the polymer flocculant in the dispersion liquid is more likely to be dispersed into the water containing bulk material than in the case of the W/O type emulsion.

Reference Signs List

[010311 Belt conveyor 2 Water-containing bulk material Tubular member 13 Outlet 13a Outlet hole 14 One end side inlet Other end side inlet 51 Tank 52 Pump 100 Flocculant adding apparatus A Major axis direction of tubular member X Width direction of belt conveyor

Claims (13)

1. [1] A method for treating a water-containing bulk material, comprising adding a flocculant to the water containing bulk material being conveyed with a belt conveyor, the method comprising: using a dispersion liquid comprising, as the flocculant, a polymer flocculant in a form of dispersion in an aqueous salt solution; using a tubular member wherein an outlet or outlets that allow the dispersion liquid to flow out over a width direction of the belt conveyor are provided in a peripheral wall along a major axis direction, the tubular member installed above the belt conveyor; and adding the dispersion liquid to the water-containing bulk material on the belt conveyor from the outlet or outlets of the tubular member.
2. [2] The method for treating a water-containing bulk material according to claim 1, comprising transferring the dispersion liquid into the tubular member using a pump, and adding the dispersion liquid allowed to flow in an inside of the tubular member to the water-containing bulk material on the belt conveyor from the outlet or outlets in adding the dispersion liquid.
3. [3] The method for treating a water-containing bulk material according to claim 2, comprising using a uniaxial eccentric screw pump as the pump.
4. [4] The method for treating a water-containing bulk material according to any one of claims 1 to 3, wherein the outlet or outlets are formed by a plurality of outlet holes provided in the peripheral wall of the tubular member along the major axis direction.
5. [5] The method for treating a water-containing bulk material according to any one of claims 1 to 4, wherein the tubular member comprises a one end side inlet and the other end side inlet for allowing the dispersion liquid to flow in an inside of the tubular member at one end side and the other end side respectively in the major axis direction, and the method comprises allowing the dispersion liquid to flow in the inside from both of the one end side inlet and the other end side inlet in the tubular member.
6. [61 The method for treating a water-containing bulk material according to any one of claims 1 to 5, wherein the polymer flocculant is a copolymer-based flocculant comprising an anionic structural unit derived from an anionic monomer and a structural unit derived from (meth)acrylamide.
7. [71 The method for treating a water-containing bulk material according to claim 6, wherein the polymer flocculant is a copolymer of (meth)acrylic acid or a (meth)acrylic acid salt, and (meth)acrylamide.
8. [81 The method for treating a water-containing bulk material according to any one of claims 1 to 7, wherein the aqueous salt solution is an aqueous ammonium sulfate solution.
9. [91 A method for treating a water-containing bulk material, comprising adding a dispersion liquid comprising a polymer flocculant in a form of dispersion in an aqueous salt solution to the water-containing bulk material.
10. [10] A flocculant adding apparatus that adds a flocculant to a water-containing bulk material being conveyed with a belt conveyor, the apparatus comprising: a tank that stores a dispersion liquid comprising, as the flocculant, a polymer flocculant in a form of dispersion in an aqueous salt solution; a tubular member that is installed above the belt conveyor, wherein an outlet or outlets that allow the dispersion liquid allowed to flow in an inside of the tubular member to flow out over a width direction of the belt conveyor are provided in a peripheral wall along a major axis direction; and a pump that transfers the dispersion liquid into the tubular member from the tank.
11. [11] The flocculant adding apparatus according to claim , wherein the outlet or outlets are formed by a plurality of outlet holes provided in the peripheral wall of the tubular member along the major axis direction.
12. [12] The flocculant adding apparatus according to claim 10 or 11, wherein the tubular member comprises a one end side inlet and the other end side inlet for allowing the dispersion liquid to flow in the inside at one end side and the other end side respectively in the major axis direction.
13. [13] The flocculant adding apparatus according to any one of claims 10 to 12, comprising a uniaxial eccentric screw pump as the pump.