[0001] Field of the invention

[0002] The disclosed technology generally provides for an iron-ore composite and method of preparing said iron-ore composite with a water-soluble polymer for agglomeration of iron ore fines and residues in the briquetting and/or pelletization process.

[0003] Background of the invention

[0004] Common briquetting and/or pelletizing processes require the use of mixed binders, such as lime, molasses, or bentonite. In turn, undesired elements, such as phosphorus, silicon, acid gangue, and/or additional slag are introduced into the briquette or pellet. Due to the current binding materials available in the pelletization and briquetting processes, these undesired elements that are introduced reduce the quality and the market value of the briquettes and pellets that are ultimately produced.

[0005] Thus, what is needed in the art is a composition and method for the briquetting and/or pelletization process which avoids the introduction of these undesired elements to improve briquette and/or pellet quality.

[0006] Summary of the invention

[0007] The disclosed technology generally provides for an iron-ore composite and method of preparing an iron-ore based composite.

[0008] In one aspect of the disclosed technology, an iron-ore based composite is provided.

[0009] The composite according to the invention may further include one or more of the following features taken in isolation or according to any possible technical combinations.

[0010] In some embodiments, the composite comprises:

- a plurality of iron ore particles, the iron ore particles comprising iron ore fines and/or iron ore residues; and

- at least one water-soluble polymer, said polymer being free of acrylamide and of acrylamide derivative, wherein said polymer is obtained by polymerizing:

- at least one anionic monomer (a) selected from acrylic acid, a salt of acrylic acid, methacrylic acid, a salt of methacrylic acid, and/or combinations thereof; and - at least one monomer (b) of formula I:

I wherein R ¹ and R ² independently represent a hydrogen atom or a CH3 group; wherein m and n independently represent a number between 0 and 250, the sum of m and n is equal to or greater than 10 and n is greater than m; and wherein [(EO) _n -(PO) _m ] represents a poly- alkoxyl chain comprising ethoxyl units EO, propoxyl units PO or combinations thereof that are distributed in blocks, alternately or randomly. In all the embodiments, it must be understood that the term “between” includes the limits of the range (for numbers n and m).

[0011] In some embodiments, the composite comprises a moisture content of less than about 15% wt. relative to the total weight of the composite.

[0012] In some embodiments, the composite is in the form of a pellet or in the form of a briquette.

[0013] In some embodiments, the composite does not comprise molasses, starch, and/or starch derivatives.

[0014] In some embodiments, the polymer has a M _w molecular weight from about 10,000 to 1,000,000 g/mol, preferably from about 15,000 to 500,000 g/mol, or from about 20,000 to 200,000 g/mol.

[0015] In some embodiments, the polymer is not neutralized. In an alternative embodiment, the polymer is totally or partially neutralized.

[0016] In some embodiments, the totally or partially neutralized polymer is neutralized by NaOH, KOH, ammonium derivatives, ammonia, amino-alkali substances, and/or combinations thereof. In particular embodiments, the amino-alkali substances comprise triethanolamine or 2-amino-2-methyl-propanol (AMP).

[0017] In some embodiments, the monomer (b) is selected from:

- monomer (bl) of formula I, wherein R ¹ represents a hydrogen atom, R ² represents a CH3 group, m represents 0, n represents a number between 10 and 250, and [(EO) _n ] represents a polyalkoxyl chain comprising ethoxyl units EO;

- monomer (b2) of formula I, wherein R ¹ represents a CH3 group, R ² represents a CH3 group, m represents 0, n represents a number between 10 and 250, and [(EO) _n ] represents a polyalkoxyl chain comprising ethoxyl units EO;

- monomer (b3) of formula I, wherein R ¹ represents a hydrogen atom, R ² represents a hy- drogen atom, m and n independently represent a number between 1 and 250, and the sum of m and n is equal to or greater than 10 and n is greater than m, and [(EO) _n - (PO)„,| represents a polyalkoxyl chain comprising ethoxyl units EO, propoxyl units PO or combinations thereof that are distributed in blocks, alternately or randomly; or

- monomer (b4) of formula I, wherein R ¹ represents a CEE group, R ² represents a hydrogen atom, m and n independently represent a number between 1 and 250, and the sum of m and n is equal to or greater than 10 and n is greater than m, and [(EO) _n - (PO)™] represents a polyalkoxyl chain comprising ethoxyl units EO, propoxyl units PO or combinations thereof that are distributed in blocks, alternately or randomly.

[0018] In yet another aspect of the disclosed technology, a method of preparing an iron-ore based composite is provided.

[0019] The method according to the invention may further include one or more of the following features taken in isolation or according to any possible technical combinations.

[0020] In some embodiments, the method comprises:

- contacting a plurality of iron ore particles, with at least one water-soluble polymer to form an agglomeration, and

- forming a composite; said iron ore particles comprising iron ore fines and/or iron ore residues; said polymer being prepared in the absence of acrylamide and of acrylamide derivative; said polymer being prepared by polymerizing at least one anionic monomer (a) selected from acrylic acid, a salt of acrylic acid, methacrylic acid, a salt of methacrylic acid, and/or combinations thereof; and at least one monomer (b) of formula I:

I

[0021] wherein R ¹ and R ² independently represent a hydrogen atom or a CEE group; wherein m and n independently represent a number between 0 and 250, the sum of m and n is equal to or greater than 10 and n is greater than m; and wherein [(EO) _n -(PO)™] represents a polyalkoxyl chain comprising ethoxyl units EO, propoxyl units PO or combinations thereof that are distributed in blocks, alternately or randomly.

[0022] In some embodiments, contacting the plurality of iron ore particles with the polymer does not increase the amount of phosphorus present in the composite. In some embodiments, contacting the plurality of iron ore particles with the polymer does not increase the amount of silicon present in the composite. [0023] In some embodiments, forming a composite comprises feeding the agglomeration into a mixer and press to form a plurality of briquettes and/or pellets.

[0024] In some embodiments, forming a composite is carried out in the absence of molasses, starch, and/or starch derivatives.

[0025] In some embodiments, the composite comprises a moisture content of less than about 15% wt. relative to the total weight of the composite.

[0026] In some embodiments, the polymer has a M _w molecular weight from about 10,000 to 1,000,000 g/mol, preferably from about 15,000 to 500,000 g/mol, or from about 20,000 to 200,000 g/mol.

[0027] In some embodiments, the polymer is not neutralized. In an alternative embodiment, the polymer is totally or partially neutralized.

[0028] In some embodiments, the totally or partially neutralized polymer is neutralized by NaOH, KOH, ammonium derivatives, ammonia, amino-alkali substances, and/or combinations thereof. In particular embodiments, the amino-alkali substances comprise triethanolamine or 2-amino-2-methyl-propanol (AMP).

[0029] In some embodiments, the monomer (b) is selected from:

- monomer (bl) of formula I, wherein R ¹ represents a hydrogen atom, R ² represents a CH3 group, m represents 0, n represents a number between 10 and 250, and [(EO) _n ] represents a polyalkoxyl chain comprising ethoxyl units EO;

- monomer (b2) of formula I, wherein R ¹ represents a CH3 group, R ² represents a CH3 group, m represents 0, n represents a number between 10 and 250, and [(EO) _n ] represents a polyalkoxyl chain comprising ethoxyl units EO;

- monomer (b3) of formula I, wherein R ¹ represents a hydrogen atom, R ² represents a hydrogen atom, m and n independently represent a number between 1 and 250, and the sum of m and n is equal to or greater than 10 and n is greater than m, and [(EO) _n - (PO),„| represents a polyalkoxyl chain comprising ethoxyl units EO, propoxyl units PO or combinations thereof that are distributed in blocks, alternately or randomly; or

- monomer (b4) of formula I, wherein R ¹ represents a CH3 group, R ² represents a hydrogen atom, m and n independently represent a number between 1 and 250, and the sum of m and n is equal to or greater than 10 and n is greater than m, and [(EO) _n - (PO)„,| represents a polyalkoxyl chain comprising ethoxyl units EO, propoxyl units PO or combinations thereof that are distributed in blocks, alternately or randomly.

[0030] Brief description of the drawings [0031] Other features, details and advantages of the invention will become apparent on reading the detailed description. The accompanying figure is given as a non-limiting example.

[0032] Fig.1 is a general schematic process diagram of a typical briquetting process in which the disclosed polymer composition may be utilized.

[0033] Detailed description of exemplary embodiments

[0034] The disclosed technology generally provides for an iron-ore composite and method of preparing a composite, and more specifically, an iron-ore composite and method of preparing a composite with a water-soluble polymer for agglomeration of iron ore fines and residues in the briquetting and/or pelletization process, where the resulting briquettes and/or pellets can be used as feed to the blast furnace.

[0035] In one aspect of the disclosed technology, an iron-ore based composite is provided. The composite comprises a plurality of iron ore particles and at least one water-soluble polymer. With the use of the polymer composition and method as disclosed herein, less moisture is present in the composite briquettes and/or pellets that are produced, resulting in less moisture being present in the blast furnace during production, and thus less energy is required. Since the energy requirement is reduced, the amount of carbon dioxide emissions is ultimately reduced as well. Further, by replacing the conventional binding materials with the disclosed water-soluble polymer composition, the quality of the briquettes/pellets are significantly improved.

[0036] The iron ore particles comprise iron ore fines and/or iron ore residues. It should be understood that the iron ore fines and/or residues as described herein can be obtained from a variety of different sources. The iron ore particles can be recovered from, for example, but not limited to, mini-mills (e.g. steel dust with electrostatic precipitation in electric arc furnace), integrated plants from raw material management (storage/transfer/grinding/sizing), from blast furnace (hydrocyclones) and from converters (coarse, dust).

[0037] The water-soluble polymer is prepared in the absence of acrylamide and of acrylamide derivative, said polymer being therefore free of acrylamide and of acrylamide derivative.

[0038] The water-soluble polymer as disclosed herein is obtained by polymerizing:

- at least one anionic monomer (a) selected from acrylic acid, a salt of acrylic acid, methacrylic acid, a salt of methacrylic acid, and/or combinations thereof, and

- at least one monomer (b) of formula I:

I wherein R ¹ and R ² independently represent a hydrogen atom or a CH3 group; wherein m and n independently represent a number between 0 and 250, the sum of m and n is equal to or greater than 10 and n is greater than m; and wherein [(EO) _n -(PO) _m ] represents a poly- alkoxyl chain comprising ethoxyl units EO, propoxyl units PO or combinations thereof that are distributed in blocks, alternately or randomly.

[0039] In some embodiments, the polymer has a M _w molecular weight from about 10,000 to 1,000,000 g/mol. In other embodiments, the polymer has a M _w molecular weight from about 15,000 to 500,000 g/mol, and in other embodiments, from about 20,000 to 200,000 g/mol.

[0040] In some embodiments, the polymer is not neutralized. In an alternative embodiment, the polymer is totally or partially neutralized.

[0041] In such embodiments, wherein the polymer is totally or partially neutralized, the polymer is neutralized by NaOH, KOH, ammonium derivatives, ammonia, amino-alkali substances, and/or combinations thereof. In some embodiments, the amino-alkali substances comprise triethanolamine or 2-amino-2-methyl-propanol (AMP).

[0042] In some embodiments, the monomer (b) of the disclosed polymer is:

- monomer (bl) of formula I, wherein R ¹ represents a hydrogen atom, R ² represents a CH3 group, m represents 0, n represents a number between 10 and 250, and [(EO) _n ] represents a polyalkoxyl chain comprising ethoxyl units EO.

[0043] In some embodiments, the monomer (b) of the disclosed polymer is:

- monomer (b2) of formula I, wherein R ¹ represents a CH3 group, R ² represents a CH3 group, m represents 0, n represents a number between 10 and 250, and [(EO) _n ] represents a polyalkoxyl chain comprising ethoxyl units EO.

[0044] In some embodiments, the monomer (b) of the disclosed polymer is:

- monomer (b3) of formula I, wherein R ¹ represents a hydrogen atom, R ² represents a hydrogen atom, m and n independently represent a number between 1 and 250, and the sum of m and n is equal to or greater than 10 and n is greater than m, and [(EO) _n - (PO)„,| represents a polyalkoxyl chain comprising ethoxyl units EO, propoxyl units PO or combinations thereof that are distributed in blocks, alternately or randomly.

[0045] In some embodiments, the monomer (b) of the disclosed polymer is:

- monomer (b4) of formula I, wherein R ¹ represents a CH3 group, R ² represents a hydrogen atom, m and n independently represent a number between 1 and 250, and the sum of m and n is equal to or greater than 10 and n is greater than m, and [(EO) _n - (PO) _m ] represents a polyalkoxyl chain comprising ethoxyl units EO, propoxyl units PO or combinations thereof that are distributed in blocks, alternately or randomly.

[0046] In a preferred embodiment, the iron-ore based composite is in the form of a pellet or in the form of a briquette.

[0047] In some embodiments, the composite does not comprise molasses, starch, and/or starch derivatives. Because the iron-ore composite of the disclosed technology does not include molasses, starch, and/or starch derivatives, undesired elements, such as, for example, phosphorus and silicon, are not introduced into the briquette or pellet, thus improving the quality of the briquettes and/or pellets obtained.

[0048] In some embodiments, the iron-ore based composite comprises a moisture content of less than about 15% wt. relative to the total weight of the composite. In some embodiments, the moisture content is less than about 12% wt. relative to the total weight of the composite, and in other embodiments, the moisture content is less than about 10% wt. relative to the total weight of the composite.

[0049] In yet another aspect of the disclosed technology, a method of preparing an iron-ore based composite is provided. The method comprises:

- contacting a plurality of iron ore particles with at least one water-soluble polymer to form an agglomeration, and

- forming a composite.

[0050] The iron ore particles comprise iron ore fines and/or iron ore residues.

[0051] The polymer is prepared in the absence of acrylamide and of acrylamide derivative.

[0052] The polymer is prepared by polymerizing at least one anionic monomer (a) selected from acrylic acid, a salt of acrylic acid, methacrylic acid, a salt of methacrylic acid, and/or combinations thereof; and at least one monomer (b) of formula I:

I wherein R ¹ and R ² independently represent a hydrogen atom or a CEE group; wherein m and n independently represent a number between 0 and 250, the sum of m and n is equal to or greater than 10 and n is greater than m; and wherein [(EO) _n -(PO) _m ] represents a polyalkoxyl chain comprising ethoxyl units EO, propoxyl units PO or combinations thereof that are distributed in blocks, alternately or randomly.

[0053] The method first provides for contacting a plurality of iron ore particles with at least one water-soluble polymer to form an agglomeration. The polymer may be applied to the iron ore particles by intimate mixing. Upon contact of the polymer and the iron particles, an agglomeration of these particles is facilitated.

[0054] In some embodiments, forming a composite is carried out in the absence of molasses, starch, and/or starch derivatives. Since formation of the composite does not include these substances, undesired elements, such as, for example, phosphorus and silicon, are not introduced into the briquette or pellet. It should be understood that any recovered iron ore composites may include trace amounts of phosphorus and/or silicon based on the source of the iron ore residues or recovered fines. However, the disclosed method does not increase the amount of phosphorus and/or silicon that is ultimately present in the final composite.

[0055] In some embodiments, contacting the plurality of iron ore particles with the polymer does not increase the amount of phosphorus present in the composite that is formed. In some embodiments, contacting the plurality of iron ore particles with the polymer does not increase the amount of silicon present in the composite that is formed.

[0056] In some embodiments, forming a composite comprises feeding the agglomeration into a mixer and press to form a plurality of briquettes and/or pellets.

[0057] The composite as described herein comprises a moisture content of less than about 15% wt. relative to the total weight of the composite. In other embodiments, the composite comprises a moisture content of less than about 12% wt. relative to the total weight of the composite, and in other embodiments, the moisture content is less than about 10% wt. relative to the total weight of the composite.

[0058] Examples

[0059] The present technology will be further described in the following examples, which should be viewed as being illustrative and should not be construed to narrow the scope of the disclosed technology or limit the scope to any particular embodiments.

[0060] The disclosed polymer Pl was prepared according to the invention . In a 1 -liter reactor under stirring, we loaded 382.5g of de-ionized water, 441.3g of monomer b (compound of formula I wherein R ¹ represents a CH3 group, R ² represents a hydrogen atom, m represents 16, n represents 48 and [(EO) _n - (PO)„,| represents a polyalkoxyl chain comprising ethoxyl units EO, propoxyl units PO) and 35.4g of monomer a (methacrylic acid). Then, two compositions of reagents in two different beakers were prepared: in the first beaker, 1.69g of ammonium persulfate solubilized in 7.5g of water; and in the second beaker, 2.033g of DMDO (l,8-dimercapto-3,6-di oxaoctane).

[0061] The reactor was heated to 64°C, and under stirring the reagents, firstly DMDO and secondly ammonium persulfate solution were introduced. The reactor was maintained under stirring for lh30min in a temperature range from 65°C to 69°C.

[0062] The polymer was neutralized with a water solution of sodium hydroxide to adjust pH at 5.0. Solid content was then adjusted by de-ionized water addition until reaching 50wt% solid content. Polymer Pl had a molecular weight of 130,000 g/mol (measured by SEC) and a polymolecularity (Ip) of 1.8.

[0063] Iron ore pellets according to the disclosed technology were then prepared while using polymer Pl. Comparative iron ore pellets were also prepared with comparative binders. For preparing the pellets, the various materials were thoroughly mixed with a planetary blender starting by introduction of the iron ore followed by water (added to obtain a constant humidity value of 12 wt% to 14 wt%) and the other ingredients. The components were blended for approximately 30 minutes.

[0064] The comparative binders that were used are: molasses with lime and starch; a sodium polyacrylate polymer having a molecular weight Mw of 5,000 g/mol (solids content = 55%); and a sodium polyacrylate polymer having a molecular weight Mw of 70,000 g/mol (solids content = 40%).

[0065] A small amount of the blended compositions was set aside to control humidity. With the remaining compositions, two sets of 3 pellets were produced with a hydraulic press in a cylindrical mold (inside diameter 41 mm) fitted with a piston. The pellets were prepared using a pressing device resulting in pellets having controlled cylindrical shape and size (41 mm diameter x 12 mm height). The weight of each pellet was 35 g. Components and amounts are presented in Table 1.

[0066] The pellets according to the disclosed technology and the comparative pellets were then subjected to evaluations of their mechanical properties.

[0067] Mechanical strength of the pellets was evaluated by a drop test whereby integrity of the pellets was controlled after 3 drops from a height of 1.5 meter. Elasticity of the pellets was evaluated by means of a 3-point bending apparatus allowing controlling the deformation of the pellets. The second test being the measure of the deformation of the pellets on a three points bending apparatus, a higher deformation giving a better resistance on impact.

[0068] For the drop testing, the pellets were pressed during one minute with a pressure of 4 tons, while for the deformation test a pressure of 2 tons was applied during 1 minute. Immediately after the pellets production the test was ran.

[0069] For the drop test, up to 4 drops were made and the appearance of the pellets was noted each time. For the deformation test, pellets were placed on two supporting rollers with a 30 mm span and pressure was applied in the center of the pellet with a third roller descending at a speed of 0. 1 mm per second. The resistance to pressure was then recorded and the displacement where resistance increases sharply was noted. The longer this displacement, the more deformable the pellet is and the less prone to breaking. Pellet composition and test results are presented in Table 1.

[0070] [Table 1]

[0071] The results confirmed the elimination of lime in order to further simplify the process and reduce the dose of the disclosed water-soluble polymer composition.

[0072] In the foregoing specification, the technology has been described with reference to specific embodiments thereof. While embodiments of the disclosed technology have been described, it should be understood that the present disclosure is not so limited and modifications may be made without departing from the disclosed technology. The scope of the disclosed technology is defined by the appended claims, and all devices, processes, and methods that come within the meaning of the claims, either literally or by equivalence, are intended to be embraced therein.