Methods for aggregating anionic gangue

Abstract

Methods of aggregating particles of anionic gangue by contacting said particles with an aggregating agent are provided. The aggregating agent comprises a compound including at least one polycyclic oxonium arene core substituted with at least one substituent comprising a linear or branched alkyl chain having a chain length of at least 6 carbon atoms.

Description

Methods for aggregating anionic gangueCross-reference to related applications

[0001] This application claims the benefit of priority from Australian provisional application no. 2024903537, filed on 30 October 2024, the contents of which is incorporated herein by reference in its entirety.Field of the disclosure

[0002] The present disclosure relates to methods of aggregating particles of anionic gangue by contacting said particles with an aggregating agent. The aggregating agent comprises a compound including at least one polycyclic oxonium arene core substituted with at least one substituent comprising a linear or branched alkyl chain having a chain length of at least 6 carbon atoms. The present disclosure also relates to aggregating agents and composites comprising particles of anionic gangue and said aggregating agents.Background of the disclosure

[0003] The mining industry uses techniques such as froth flotation for the separation of valuable minerals from waste “gangue”. In froth flotation, chemical additives are used to modify the surface properties of the different ore components. Surfactants are utilised to generate froths that facilitate the attachment of hydrophobic particles to the air-solution interface, resulting in the flotation of the hydrophobic species.

[0004] Current reagents for flotation of anionic gangue (e.g., quartz and clays) include quaternary ammonium surfactants, such as cetylammonium bromide. These reagents are composed of a small positively charged hydrophilic head group and a long-chain hydrophobic hydrocarbon component. These structures are problematic, as they will associate electrostatically with any anionic surface and render it hydrophobic with very little driving force to differentiate based on the chemistry of the surface.

[0005] Aggregation can also be achieved using inorganic salts, such as alum (Al2(SC>4)3) or ferric chloride (FeCh). These salts are susceptible to displacement by other ions in the high ionic strength conditions typically found in mineral processing situations and therefore limit their viability.1006207079

[0006] Polymeric materials are also widely used (e.g., high molecular weight polyacrylamide) due to their ability to neutralise charge and make contacts with numerous particles, resulting in flocculation. However, these degrade slowly and result in ‘sludgy’ aggregates that are difficult to process further.

[0007] There has been essentially no development of the chemistry to achieve the selective collection and flotation of clay as it has traditionally been viewed as a waste material due to it being exceptionally difficult to beneficiate in a cost-effective manner. Consequently, clays are typically flocculated, sedimented and sent to tailings dams. Therefore, there is a need to improve mineral recovery from these tailings while also minimising environmental impact.

[0008] Reference to any prior art in the specification is not an acknowledgment or suggestion that this prior art forms part of the common general knowledge in any jurisdiction or that this prior art could reasonably be expected to be understood, regarded as relevant, and / or combined with other pieces of prior art by a skilled person in the art.Summary of the disclosure

[0009] In a first aspect, the present disclosure provides a method of aggregating particles of anionic gangue in an aqueous anionic gangue suspension, the method comprising contacting the aqueous anionic gangue suspension with an aggregating agent, thereby forming an anionic gangue aggregating agent composite, wherein the aggregating agent comprises at least one polycyclic oxonium arene core substituted with at least one substituent comprising a linear or branched alkyl chain, said alkyl chain having a chain length of at least 6 carbon atoms.

[0010] In a further aspect, the present disclosure provides a method of concentrating particles of anionic gangue in an aqueous anionic gangue suspension, the method comprising subjecting the anionic gangue aggregating agent composite formed by the method according to any one of the herein disclosed embodiments to one or more physical separation processes.

[0011] In some embodiments, the one or more physical separation processes comprise one or more of filtration, evaporation, centrifugation, sedimentation and froth flotation.1006207079

[0012] In a further aspect, the present disclosure provides a composite comprising particles of anionic gangue and an aggregating agent, said aggregating agent comprising at least one polycyclic oxonium arene core substituted with at least one substituent comprising a linear or branched alkyl chain, said alkyl chain having a chain length of at least 6 carbon atoms.

[0013] In some embodiments, the concentration of aggregating agent in the aqueous anionic gangue suspension is from about 0.2 ppm to about 200 ppm, ppm defined as weight / volume.

[0014] In some embodiments, the amount of aggregating agent to anionic gangue is from about 0.1 pmol to about 100 pmol of aggregating agent per gram of anionic gangue.

[0015] In some embodiments, the at least one substituent comprising a linear or branched alkyl chain is attached directly to the polycyclic oxonium arene core.

[0016] In some alternative embodiments, the at least one substituent comprising a linear or branched alkyl chain is attached to the polycyclic oxonium arene core through a heteroatom, through an arene ring, or a combination thereof.

[0017] In some embodiments, the heteroatom is selected from the group consisting of O, N and S.

[0018] In some embodiments, the aggregating agent is a compound of Formula (I) or a salt thereof:Formula (I), wherein,X" is an anion;1006207079L is an aryl group, or a covalent bond between the oxonium arene and R1;R1and R2are independently selected from -Cnalkyl, -OCnalkyl and -N(R3)Cnalkyl;R3is selected from H and -Cnalkyl; in at least one instance n is a number greater than or equal to 6; and wherein the alkyl groups are independently straight-chained or branched.

[0019] In some alternative embodiments, the aggregating agent is a compound of Formula (II) or a salt thereof:Formula (II), wherein,X" is an anion; each L is an aryl group or a covalent bond between the oxonium arene and the nitrogen; each R1is independently selected from H and -Cnalkyl; each R2is independently selected from -Cnalkyl, -OCnalkyl and -N(R1)Cnalkyl;R3is -Cnalkyl; in at least one instance n is a number greater than or equal to 6; and wherein the alkyl groups are independently straight-chained or branched.

[0020] In some alternative embodiments, the aggregating agent is a compound of Formula (la) or a salt thereof;1006207079Formula (la) wherein,X" is an anion;R1and R2are independently selected from -Cnalkyl, -OCnalkyl and -N(R3)Cnalkyl;R3is selected from H and -Cnalkyl; and in at least one instance n is a number greater than or equal to 6; and wherein the alkyl groups are independently straight-chained or branched.

[0021] In some alternative embodiments, the aggregating agent is a compound of Formula (Ila) or a salt thereof;Formula (Ila), wherein,X" is an anion; each R1is independently selected from H and -Cnalkyl; each R2is independently selected from -Cnalkyl, -OCnalkyl and -N(R1)Cnalkyl;R3is -Cnalkyl; in at least one instance n is a number greater than or equal to 6; and1006207079wherein the alkyl groups are independently straight-chained or branched.

[0022] In some alternative embodiments, the aggregating agent is a compound of Formula (lb) or a salt thereof;Formula (lb) wherein,X" is an anion;R1and R2are independently selected from -Cnalkyl, -OCnalkyl and -N(R3)Cnalkyl;R3is selected from H and -Cnalkyl; in at least one instance of n is a number greater than or equal to 6; and wherein the alkyl groups are independently straight-chained or branched.

[0023] In some alternative embodiments, the aggregating agent is a compound of Formula (lib) or a salt thereof;Formula (lib), wherein,X" is an anion;1006207079each R1is independently selected from H and -Cnalkyl; each R2is independently selected from -Cnalkyl, -OCnalkyl and -N(R1)Cnalkyl;R3is -Cnalkyl; in at least one instance n is a number greater than or equal to 6; and wherein the alkyl groups are independently straight-chained or branched.

[0024] In a further aspect, the present disclosure provides a compound according to any one of Formulae (I), (II), (la), (lb), (Ila) and (lib).

[0025] In some embodiments, in at least one instance n is an integer from 6 to 15, or from 7 to 13.

[0026] In some embodiments, X" is selected from one or more of halide, for example chloride, hydrogen sulfate, hexafluorophosphate and trifluoroacetate.

[0027] In some embodiments, R1is -N(R3)Cnalkyl.

[0028] In some embodiments, R2is -N(R3)Cnalkyl.

[0029] In some embodiments, the aggregating agent is a compound selected from one or more of the following:1006207079

[0030] In some embodiments, the anionic gangue comprises one or more of silica (for example, quartz), clay, carbonate minerals, sulphate minerals or phosphate minerals.

[0031] In some embodiments, the clay comprises one or more of kaolinite, illite, smectites and vermiculite.

[0032] In some embodiments, the silica comprises quartz.

[0033] In some embodiments, the particles of anionic gangue have a mean diameter from about 5 pm to about 100 pm, or from about 5 pm to about 50 pm, or from about 5 pm and about 15 pm.

[0034] In some embodiments, the particles of anionic gangue are constituents of a mineral mixture or mineral tailings.

[0035] In some embodiments, the aqueous anionic gangue suspension is a saline aqueous anionic gangue suspension.

[0036] In another aspect the present disclosure provides a method of selectively aggregating particles of clay from particles of quartz the method comprising contacting1006207079an aqueous suspension comprising clay and quartz particles with an aggregating agent, wherein the aggregating agent is in an amount sufficient to form a clay aggregating agent composite, thereby selectively aggregating the particles of clay from the particles of quartz, and wherein the aggregating agent comprises at least one polycyclic oxonium arene core substituted with at least one substituent comprising a linear or branched alkyl chain, said alkyl chain having a chain length of at least 6 carbon atoms.

[0037] In some embodiments, the aqueous suspension comprising clay and quartz has a clay:quartz weight ratio of about 1:1.

[0038] In embodiments, the aggregating agent comprises an aggregating agent according to any one of the herein disclosed embodiments.

[0039] In some embodiments, the aggregating agent is present in the aqueous suspension in an amount less than about 0.1 wt.%.

[0040] In some embodiments of any one of the herein disclosed methods, the methods further comprise adding a frother to the aqueous anionic gangue suspension or the aqueous suspension comprising clay and quartz.

[0041] In some embodiments, the frother is added in an amount from about 0.001% to about 0.1% v / v.

[0042] In some embodiments, the frother comprises one or more alcohols, glycols, ethers, heterocyclic compounds, or surfactants.

[0043] In some embodiments, the frother is methyl isobutyl carbinol.

[0044] In a further aspect, the present disclosure provides a method of preparing an aggregating agent according to Formula (I), (la), or (lb), the method comprising contacting a compound of Formula XFormula X, with a compound of Formula Y,1006207079Formula Y, in the presence of a strong acid and / or Lewis acid, thereby forming the aggregating agent according to Formula (I), (la) or (lb), whereinR1is selected from -Cnalkyl, or an aryl group optionally substituted by -Cnalkyl, - OCnalkyl or -N(R3)Cnalkyl;R2is selected from -Cnalkyl, -OCnalkyl and -N(R3)Cnalkyl;R3is selected from H and -Cnalkyl; in at least one instance of n is a number greater than or equal to 6; and wherein the alkyl groups are independently straight-chained or branched.

[0045] In a further aspect, the present disclosure provides a method of preparing an aggregating agent according to Formula (la), or (lb), the method comprising contacting a compound of Formula XFormula X, with a compound of Formula Z,Formula Z, in the presence of a strong acid and / or Lewis acid, thereby forming the aggregating agent according to Formula (la) or (lb), whereinR1and R2are independently selected from -Cnalkyl, -OCnalkyl and -N(R3)Cnalkyl;1006207079R3is selected from H and -Cnalkyl; in at least one instance of n is a number greater than or equal to 6; and wherein the alkyl groups are independently straight-chained or branched.

[0046] In a further aspect, the present disclosure provides a method of preparing an aggregating agent according to Formula (II), (Ila), or (lib), the method comprising contacting a compound of Formula XFormula X, with a compound of Formula A,Formula A, in the presence of a strong acid and / or Lewis acid, thereby forming the aggregating agent according to Formula (II), (Ila) or (lib), wherein each L is an aryl group or a covalent bond; each R1is independently selected from H and -Cnalkyl; each R2is independently selected from -Cnalkyl, -OCnalkyl and -N(R1)Cnalkyl;R3is -Cnalkyl; in at least one instance of n is a number greater than or equal to 6; and wherein the alkyl groups are independently straight-chained or branched.1006207079

[0047] In a further aspect, the present disclosure provides a method of preparing an aggregating agent according to Formula (Ila), or (lib), the method comprising contacting a compound of Formula XFormula X, with a compound of Formula B,Formula B, in the presence of a strong acid and / or Lewis acid, thereby forming the aggregating agent according to Formula (Ila) or (lib), wherein each R1is independently selected from H and -Cnalkyl; each R2is independently selected from -Cnalkyl, -OCnalkyl and -N(R1)Cnalkyl;R3is -Cnalkyl; in at least one instance of n is a number greater than or equal to 6; and wherein the alkyl groups are independently straight-chained or branched.

[0048] In some embodiments, the method of preparing an aggregating agent according to Formula (II), (Ila), or (lib) further comprises preparing the compound of Formula A or the compound of Formula B by contacting a compound of Formula C or Formula D,Formula C1006207079Formula D with an alkyl group including a leaving group and a base, thereby forming the compound of Formula A or the compound of Formula B, wherein each L is an aryl group or a covalent bond; andR3is straight-chained or branched -Cnalkyl.

[0049] In some embodiments, the leaving group comprises a halide, for example bromide.

[0050] In some embodiments, the method of preparing an aggregating agent according to Formula (Ila), or (lib) further comprises preparing the compound of Formula D by contacting a compound of Formula EFormula E with a compound of Formula F,H2N NH \2R3'Formula F in the presence of a copper (I) salt and a base, thereby forming the compound ofFormula D, whereinX is a leaving group; andR3is straight-chained or branched -Cnalkyl.1006207079

[0051] In some embodiments, the leaving group comprises a halide, for example iodide.

[0052] In some embodiments, R1is -N(R3)Cnalkyl.

[0053] In some embodiments, R2is -N(R3)Cnalkyl.

[0054] In some embodiments, the strong acid is selected from one or more of HCI, HPFe, H2SO4 or HBF4. Preferably, the strong acid is H2SO4.

[0055] In some embodiments, the Lewis acid is selected from BF3*Et2O.

[0056] In embodiments, advantages of the presently disclosed methods and composites include one or more of the following:• The aggregating agent is “potentially” biodegradable / recoverable.• The aggregating agent has a strong binding affinity for anionic gangue (for example clays of various types (kaolin and smectite)) resulting in utility in highly saline water (which is not possible for a range of current reagents, such as alum).• The hydrophobic groups of the aggregating agent achieve significant flocculation while rendering the particles hydrophobic when compared to, for example, polyacrylamide, simplifying the dewatering process (reducing the energy and water required).• The aggregating agent may allow access to valuable minerals that do not bind in prior methods.

[0057] Further aspects of the present invention and further embodiments of the aspects described in the preceding paragraphs will become apparent from the following description, given by way of example and with reference to the accompanying drawings.Brief description of the drawings

[0058] Figure 1 . Scheme showing the reaction pathway and conditions for the synthesis of M8Flav (compound 6; R=CsHi7), M12Flav (compound 7; R=Ci2H2s), and D8Flav (compound 10; R=CsHi7).1006207079

[0059] Figure 2. Scheme showing an exemplary reaction pathway and conditions for the synthesis of selected compounds of the present disclosure.

[0060] Figure 3. Adsorption of aggregating agent on kaolinite particles as a function of dosage, conducted under conditions in Table 1 , at pH 6.5.

[0061] Figure 4. FTIR spectra of (a) kaolinite (K-1) and M12Flav treated kaolinite (K- M12Flav-8), dotted line box indicates the expanded section shown in Figure 4(b); (b) Expanded FTIR spectrum of M12Flav treated kaolinite in the range of 3500-1200 cm-1(c) FTIR spectrum of M12Flav dry powder.

[0062] Figure 5. Single crystal structures of (A) M12Flav (B) M8Flav, (C) D8Flav, and (D) (a) and (b) possible interactions between the kaolinite surface and oxonium.

[0063] Figure 6. Length weighted (a) and cube-weighted (b) chord length distributions of kaolinite treated with different concentrations of M12Flav under 200 rpm, 2.1 g / L kaolinite concentration at pH 6.4 measured by Blaze probe. Traces in the length weighted chord length distribution data are K-M12Flav-2, K-1, K-M12Flav-3, K-M12Flav- 4, K-M12Flav-6 and K-M12Flav-5 in order from highest to lowest peak height. Traces in the cube-weighted chord length distribution data are K-M12Flav-5, K-M12Flav-6, K- M12Flav-4, K-M12Flav-3, K-M12Flav-2 and K-1 in order from highest to lowest peak height.

[0064] Figure 7. (a) Median cube-weighted chord length as a function of Flav dosage at 200 rpm stirring, 2.1 g / L kaolinite concentration and pH 6.4. (b) Effect of Flav type and dosage on the turbidity of supernatant and comparison with commercial hydrophobic modifier, CTAB. Traces in the median particle size graph K-M12Flav, K- D8Flav and K-M8Flav in order from top to bottom. Traces in turbidity graph are K- M8Flav, K-CTAB, K-M12Flav and K-D8Flav (K-M12Flav and K-D8Flav essentially overlapping) in order from top to bottom.

[0065] Figure 8. Real time Blaze probe images of kaolinite aggregates after treating with different concentrations of D8Flav under the conditions in Table 1.

[0066] Figure 9. Real time Blaze probe images of kaolinite aggregates after treating with different concentrations of M12Flav under the conditions in Table 1.1006207079

[0067] Figure 10. Variation of water contact angle of kaolinite after treating with M8Flav, M12Flav and D8Flav dosage under the conditions in Table 1.

[0068] Figure 11. Graph showing the normalised height of the solid liquid interface of kaolinite slurry as a function of time, before and after treating with M12Flav, D8Flav and M8Flav.

[0069] Figure 12. (a) PXRD patterns of pure kaolinite and quartz. Characteristic peaks used for phase quantification are labelled (kaolinite; 12.4°, quartz; 26.7°), (b) PXRD patterns of the feed; kaolinite-quartz mixture (1:1), flotation concentrate (C), and the tailings (T). Peaks corresponding to kaolinite; 12.4° 20 (♦) and quartz; 26.7° 20 (o) are labelled. The relative intensities highlight the selective separation achieved during flotation. All graphs were normalized to the intensity of the quartz peak at 26.7° 20.

[0070] Figure 13. Graph showing the variation of the peak integration ratio (IR) of flotation concentrate and tailings as a function of M12Flav dosage. The IR values were calculated from PXRD peak areas of kaolinite (001) and quartz (101). Cumulative mineral mass recovery (Rc) (%) is also plotted to show flotation performance with increasing aggregating agent dosage.

[0071] Figure 14. Graph showing the recovery and grade of kaolinite and quartz in concentrate vs M12Flav dosage (wt%).

[0072] Figure 15. Graph showing length-weighted (solid lines, left y-axis) and cube- weighted (dashed lines, right y-axis) counts against chord lengths for quartz in the absence of M12Flav and after two minutes conditioning with M12Flav aggregating agent (0.2wt%).Detailed description of the embodiments

[0073] It will be understood that the invention disclosed and defined in this specification extends to all alternative combinations of two or more of the individual features mentioned or evident from the text or drawings. All of these different combinations constitute various alternative aspects of the invention.

[0074] One skilled in the art will recognize many methods and materials similar or equivalent to those described herein, which could be used in the practice of the present disclosure. The present disclosure is in no way limited to the methods and materials1006207079described. It will be understood that the disclosure described and defined in this specification extends to all alternative combinations of two or more of the individual features mentioned or evident from the text or drawings. All of these different combinations constitute various alternative aspects of the disclosure.

[0075] For the purposes of interpreting this specification, terms used in the singular will also include the plural and vice versa.

[0076] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present disclosure belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present disclosure, preferred methods and materials are described. For the purposes of the present disclosure, the following terms are defined below.

[0077] The articles “a” and “an” are used herein to refer to one or to more than one (i.e. to at least one) of the grammatical object of the article. By way of example, “a membrane surface” means one surface of a membrane or more than one surface of a membrane.

[0078] As used herein, the term “and / or”, e.g., “X and / or Y” will be understood to mean either “X and Y” or “X or Y” and shall be taken to provide explicit support for both meanings or for either meaning.

[0079] As used herein, the term “about” refers to a quantity, value, dimension, size, or amount that varies by as much as 10%, 5%, 1% or 0.1 % to a reference quantity, value, dimension, size, or amount.

[0080] Throughout the present disclosure, various aspects of the disclosure can be presented in a range format. It should be understood that the description in range format is merely for convenience and brevity and should not be construed as an inflexible limitation on the scope of the disclosure. Accordingly, the description of a range should be considered to have specifically disclosed all the possible subranges as well as individual numerical values within that range. For example, description of a range such as from 1 to 6 should be considered to have specifically disclosed subranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 31006207079to 6 etc., as well as individual numbers within that range, for example, 1 , 2, 2.7, 3, 4, 5, 5.3, and 6. This applies regardless of the breadth of the range.

[0081] As used herein, except where the context requires otherwise, the term “comprise” and variations of the term, such as “comprising”, “comprises” and “comprised”, are not intended to exclude further additives, components, integers or steps.

[0082] The term “polycyclic oxonium arene” refers to a class of compounds that is composed of multiple aromatic rings, at least one of those aromatic rings containing an oxonium cation. An oxonium cation is any cation containing a trivalent oxygen atom with a 1+ formal charge.

[0083] “Alkyl” refers to an unbranched (straight-chained) or branched saturated hydrocarbon chain. For example, CnAlkyl refers to an alkyl chain comprising n number of carbon atoms. Examples of suitable alkyl groups include, but are not limited to, 1-hexyl (-CH2CH2CH2CH2CH2CH3), 2-hexyl (-CH(CH3)CH2CH2CH2CH3),3-hexyl (-CH(CH2CH3)(CH2CH2CH3)), 2-methyl-2-pentyl (-C(CH3)2CH2CH2CH3), 3-methyl-2-pentyl (-CH(CH3)CH(CH3)CH2CH3), 4-methyl-2-pentyl (-CH(CH3)CH2CH(CH3)2), 3-methyl-3-pentyl (-C(CH3)(CH2CH3)2), 2-methyl-3-pentyl (- CH(CH2CH3)CH(CH3)2), 2,3-dimethyl-2-butyl (-C(CH3)2CH(CH3)2), and 3,3-dimethyl-2- butyl (-CH(CH3)C(CH3)3, 1 -heptyl (-CH2CH2CH2CH2CH2CH2CH3), 2-heptyl (-CH(CH3)CH2CH2CH2CH2CH3), 3-heptyl (-CH(CH2CH3)(CH2CH2CH2CH3)), 1-octyl (-CH2CH2CH2CH2CH2CH2CH2CH3), 1-nonyl (-CH2CH2CH2CH2CH2CH2CH2CH2CH3), 1- decyl (-CH2CH2CH2CH2CH2CH2CH2CH2CH2CH3) and the like.

[0084] Disclosed herein are new methods of aggregating and / or concentrating anionic gangue particles using an aggregating agent comprising at least one polycyclic oxonium arene core substituted with at least one substituent comprising a linear or branched alkyl chain, said alkyl chain having a chain length of at least 6 carbon atoms. Also disclosed are composites comprising anionic gangue and said aggregating agent.Methods of aggregating and / or concentrating anionic gangue

[0085] The present disclosure relates to a method of aggregating particles of anionic gangue in an aqueous anionic gangue suspension, the method comprising contacting the aqueous anionic gangue suspension with an aggregating agent, thereby forming an1006207079anionic gangue aggregating agent composite, wherein the aggregating agent comprising at least one polycyclic oxonium arene core substituted with at least one substituent comprising a linear or branched alkyl chain, said alkyl chain having a chain length of at least 6 carbon atoms.

[0086] The present disclosure also relates to a method of concentrating particles of anionic gangue in an aqueous anionic gangue suspension, the method comprising subjecting the anionic gangue aggregating agent composite formed by the method according to any one of the herein disclosed embodiments to one or more physical separation processes.

[0087] In embodiments, the one or more physical separation processes comprise one or more of filtration, evaporation, centrifugation, sedimentation or froth flotation.

[0088] In some embodiments, the physical separation process is froth flotation. Froth flotation is a separation process for selectively separating hydrophobic materials from hydrophilic materials. The process employs bubbling a gas (typically air) through a suspension / solution in a general flotation tank, Jameson flotation cell, or flotation column. The gas bubbles bring suspended particles to the solutions surface, where they can be separated from the bulk solution.

[0089] In some embodiments, the aqueous anionic gangue suspension may be a saline aqueous anionic gangue suspension.Methods of separating clay from quartz

[0090] In another aspect, the present disclosure provides a method of selectively aggregating particles of clay from particles of quartz the method comprising contacting an aqueous suspension comprising clay and quartz particles with an aggregating agent, wherein the aggregating agent is in an amount sufficient to form a clay aggregating agent composite, thereby selectively aggregating the particles of clay from the particles of quartz, and wherein the aggregating agent comprises at least one polycyclic oxonium arene core substituted with at least one substituent comprising a linear or branched alkyl chain, said alkyl chain having a chain length of at least 6 carbon atoms.

[0091] In some embodiments, the aqueous suspension comprising clay and quartz has a clay: quartz ratio of about 1:1.1006207079

[0092] In some embodiments, the aggregating agent comprises an aggregating agent according to any one of the herein disclosed embodiments.

[0093] In some embodiments, the aggregating agent is present in the aqueous suspension in an amount less than about 0.1 wt%.Frothers

[0094] In some embodiments of any one of the herein disclosed methods, the methods may further comprise adding a frother to the aqueous anionic gangue suspension or the aqueous suspension comprising clay and quartz.

[0095] As used herein, a frother is a compound or mixture of compounds that act to stabilise air bubbles so they remain well-dispersed in the slurry and form a stable frother layer which can be removed before the bubbles burst.

[0096] In some embodiments, the frother may be added in an amount from about 0.001% to about 0.1% v / v.

[0097] In some embodiments, the frother may comprises one or more alcohols, glycols, ethers, heterocyclic compounds or surfactants.

[0098] Examples of alcohols may include one or more of methyl isobutyl carbinol, polyglycol ethers (eg Dowfroth), terpineol or cresylic acid.

[0099] Examples of glycols may include one or more of propylene glycol, polyethylene glycol or polypropylene glycol.

[0100] Examples of ethers may include one or more of diethylene glycol monobutyl ether (DGMBE), dipropylene glycol monomethyl ether (DPGME) or polyethylene glycol monobutyl ether (PEGMBE).

[0101] Examples of heterocyclic compounds may include methylpyridine, methylpyrrolidone or furfuryl alcohol.

[0102] Examples of surfactants may include sodium dodecyl sulphate (SDS), polyoxyethylene alkyl ethers or alkyl sulphates.1006207079

[0103] In some embodiments, the frother is methyl isobutyl carbinol. Other frothers known in the art are contemplated.Aggregating agent

[0104] The present disclosure further provides a composite comprising particles of anionic gangue and an aggregating agent, said aggregating agent comprising at least one polycyclic oxonium arene core substituted with at least one substituent comprising a linear or branched alkyl chain, said alkyl chain having a chain length of at least 6 carbon atoms.

[0105] As used herein, the term aggregating agent refers to a compound that facilitates the combining of smaller particles to form a larger aggregate. The aggregating agents described by the present disclosure are able to form composites with particles of anionic gangue.

[0106] In some embodiments, the concentration of aggregating agent in the aqueous anionic gangue suspension may be from about 0.2 ppm to about 200 ppm, ppm defined as weight / volume.

[0107] In some embodiments, the amount of aggregating agent to anionic gangue may be from about 0.1 pmol to about 100 pmol per gram of anionic gangue, or from about 0.1 pmol to about 90 pmol per gram of anionic gangue, or from about 0.1 pmol to about 80 pmol per gram of anionic gangue, or from about 0.1 pmol to about 70 pmol per gram of anionic gangue, or from about 0.1 pmol to about 60 pmol per gram of anionic gangue, or from about 0.1 pmol to about 50 pmol per gram of anionic gangue.

[0108] In some embodiments, at least one substituent comprising a linear or branched alkyl chain may be attached directly to the polycyclic oxonium arene core.

[0109] In some alternative embodiments, at least one substituent comprising a linear or branched alkyl chain may be attached to the polycyclic oxonium arene core through a heteroatom, through an arene ring, or a combination thereof.

[0110] In some embodiments, the heteroatom may be selected from the group consisting of O, N and S. Preferably, the heteroatom is selected from the group consisting of O and N. Most preferably, the heteroatom is N.1006207079

[0111] In some embodiments, the polycyclic oxonium arene core comprises a pyrylium ion, a chromenylium ion, a flavylium ion or a naphthoxanthenium ion. Preferably, the polycyclic oxonium arene core is a flavylium ion.

[0112] In some embodiments, the aggregating agent may be a compound of Formula (I) or a salt thereof:Formula (I), wherein,X" is an anion;L is an aryl group, or a covalent bond between the oxonium arene and R1;R1and R2are independently selected from -Cnalkyl, -OCnalkyl and -N(R3)Cnalkyl;R3is selected from H and -Cnalkyl; in at least one instance n is a number greater than or equal to 6; and wherein the alkyl groups are independently straight-chained or branched.

[0113] In some alternative embodiments, the aggregating agent may be a compound of Formula (II) or a salt thereof:Formula (II),1006207079wherein,X" is an anion; each L is an aryl group or a covalent bond between the oxonium arene and the nitrogen; each R1is independently selected from H and -Cnalkyl; each R2is independently selected from -Cnalkyl, -OCnalkyl and -N(R1)Cnalkyl;R3is -Cnalkyl; in at least one instance n is a number greater than or equal to 6; and wherein the alkyl groups are independently straight-chained or branched.

[0114] In some alternative embodiments, the aggregating agent may be a compound of Formula (la) or a salt thereof;Formula (la) wherein,X" is an anion;R1and R2are independently selected from -Cnalkyl, -OCnalkyl and -N(R3)Cnalkyl;R3is selected from H and -Cnalkyl; and in at least one instance n is a number greater than or equal to 6; and wherein the alkyl groups are independently straight-chained or branched.

[0115] In some alternative embodiments, the aggregating agent may be a compound of Formula (Ila) or a salt thereof;1006207079Formula (Ila), wherein,X" is an anion; each R1is independently selected from H and -Cnalkyl; each R2is independently selected from -Cnalkyl, -OCnalkyl and -N(R1)Cnalkyl;R3is -Cnalkyl; in at least one instance n is a number greater than or equal to 6; and wherein the alkyl groups are independently straight-chained or branched.

[0116] In some alternative embodiments, the aggregating agent may be a compound of Formula (lb) or a salt thereof;Formula (lb) wherein,X" is an anion;R1and R2are independently selected from -Cnalkyl, -OCnalkyl and -N(R3)Cnalkyl;R3is selected from H and -Cnalkyl;1006207079in at least one instance of n is a number greater than or equal to 6; and wherein the alkyl groups are independently straight-chained or branched.

[0117] In some alternative embodiments, the aggregating agent may be a compound of Formula (lib) or a salt thereof;Formula (lib), wherein,X" is an anion; each R1is independently selected from H and -Cnalkyl; each R2is independently selected from -Cnalkyl, -OCnalkyl and -N(R1)Cnalkyl;R3is -Cnalkyl; in at least one instance n is a number greater than or equal to 6; and wherein the alkyl groups are independently straight-chained or branched.

[0118] In a further aspect, the present disclosure provides a compound according to Formula (I), (II), (la), (lb), (Ila) or (lib).

[0119] In some embodiments, in at least one instance n may be an integer from 6 to 15, or from 7 to 13.

[0120] In some embodiments, R1may be -N(R3)Cnalkyl.

[0121] In some embodiments, R2may be -N(R3)Cnalkyl.

[0122] In some embodiments, the aggregating agent is a compound selected from one or more of the following:1006207079Anions

[0123] Any anion, X", may be used in the present disclosure. The selection of the anion is not critical to the invention and specific anions may be selected for several reasons. For example, the anion may be selected to improve the stability of the aggregating agent upon storage or make handling the aggregating agent easier due to the morphology of the material when solid.1006207079

[0124] In some embodiments, X" may be selected from one or more of halides, for example, chloride, hydrogen sulfate, hexafluorophosphate and trifluoroacetate. Other suitable anions known in the art are contemplated.Anionic gangue

[0125] Anionic gangue refers to materials that are a type of mineral impurity that can be found in mining operations. These materials have a negative electrical charge and can be problematic in the extraction and processing of valuable minerals.

[0126] In some embodiments, the anionic gangue comprises one or more of silica, clay, carbonate minerals, sulphate minerals or phosphate minerals.

[0127] In some embodiments, the silica comprises quartz, chalcedony or other silica- rich minerals. Other types of silica are contemplated.

[0128] In some embodiments, the carbonate minerals comprise calcite or dolomite. Other types of carbonate minerals are contemplated.

[0129] In some embodiments, the sulphate minerals comprise gypsum or barite. Other types of sulphate minerals are contemplated.

[0130] In some embodiments, the phosphate minerals comprise apatite. Other types of phosphate are contemplated.

[0131] The particles of anionic gangue may have a mean diameter from about 5 pm to about 100 pm, or from about 5 pm to about 50 pm, or from about 5 pm and about 15 pm.

[0132] In some embodiments, the particles of anionic gangue may be constituents of a mineral mixture or mineral tailings.Clay

[0133] In the present disclosure, the anionic gangue may be a clay. The clay may comprise any swelling clay or non-swelling clay.

[0134] The clay may comprise one or more of kaolinite, illite, smectites or vermiculite. Other clay types are contemplated.1006207079

[0135] Kaolinite is typically formed by the decomposition of orthoclase feldspar (in granite) and is the principal constituent of China clay. Examples of Kaolinite clay includes dickite and nacrite. Other examples known in the art are contemplated.

[0136] Illite is one of the most common clay minerals and is typically formed by the decomposition of some micas and feldspars. A predominant source of illite clays are marine clays and shales. Examples of illite clays include glauconite. Other examples known in the art are contemplated.

[0137] Smectites (are typically formed by the alteration of mafic igneous rock that is rich in calcium and magnesium. Smectites typically have high swelling / shrinking potential. Examples include montmorillinite, bentonite (of which montmorillinite is a main constituent) and vermiculite. Other examples known in the art are contemplated.

[0138] The particles of clay may have a mean diameter from about 5 pm to about 100 pm, or from about 5 pm to about 50 pm, or from about 5 pm and about 15 pm.

[0139] In some embodiments, the particles of clay may be constituents of a mineral mixture or mineral tailings.Methods of preparing aggregating agents

[0140] In a further aspect, the present disclosure provides a method of preparing an aggregating agent according to Formula (I), (la), or (lb), the method comprising contacting a compound of Formula XFormula X, with a compound of Formula Y,Formula Y,1006207079in the presence of a strong acid and / or Lewis acid, thereby forming the aggregating agent according to Formula (I), (la) or (lb), whereinR1is selected from -Cnalkyl, or an aryl group optionally substituted by -Cnalkyl, - OCnalkyl or -N(R3)Cnalkyl;R2is selected from -Cnalkyl, -OCnalkyl and -N(R3)Cnalkyl;R3is selected from H and -Cnalkyl; in at least one instance of n is a number greater than or equal to 6; and wherein the alkyl groups are independently straight-chained or branched.

[0141] In a further aspect, the present disclosure provides a method of preparing an aggregating agent according to Formula (la), or (lb), the method comprising contacting a compound of Formula XFormula X, with a compound of Formula Z,Formula Z, in the presence of a strong acid and / or Lewis acid, thereby forming the aggregating agent according to Formula (la) or (lb), whereinR1and R2are independently selected from -Cnalkyl, -OCnalkyl and -N(R3)Cnalkyl;R3is selected from H and -Cnalkyl; in at least one instance of n is a number greater than or equal to 6; and1006207079wherein the alkyl groups are independently straight-chained or branched.

[0142] In a further aspect, the present disclosure provides a method of preparing an aggregating agent according to Formula (II), (Ila), or (lib), the method comprising contacting a compound of Formula XFormula X, with a compound of Formula A,Formula A, in the presence of a strong acid and / or Lewis acid, thereby forming the aggregating agent according to Formula (II), (Ila) or (lib), wherein each L is an aryl group or a covalent bond; each R1is independently selected from H and -Cnalkyl; each R2is independently selected from -Cnalkyl, -OCnalkyl and -N(R1)Cnalkyl;R3is -Cnalkyl; in at least one instance of n is a number greater than or equal to 6; and wherein the alkyl groups are independently straight-chained or branched.

[0143] In a further aspect, the present disclosure provides a method of preparing an aggregating agent according to Formula (Ila), or (lib), the method comprising contacting a compound of Formula X1006207079Formula X, with a compound of Formula B,Formula B, in the presence of a strong acid and / or Lewis acid, thereby forming the aggregating agent according to Formula (Ila) or (lib), wherein each R1is independently selected from H and -Cnalkyl; each R2is independently selected from -Cnalkyl, -OCnalkyl and -N(R1)Cnalkyl;R3is -Cnalkyl; in at least one instance of n is a number greater than or equal to 6; and wherein the alkyl groups are independently straight-chained or branched.

[0144] In some embodiments, the method of preparing an aggregating agent according to Formula (II), (Ila), or (lib) further comprises preparing the compound of Formula A or the compound of Formula B by contacting a compound of Formula C or Formula D,1006207079Formula D with an alkyl group including a leaving group and a base, thereby forming the compound of Formula A or the compound of Formula B, wherein each L is an aryl group or a covalent bond; andR3is straight-chained or branched -Cnalkyl.

[0145] In some embodiments, the leaving group comprises a halide, for example bromide.

[0146] In some embodiments, the method of preparing an aggregating agent according to Formula (Ila), or (lib) further comprises preparing the compound of Formula D by contacting a compound of Formula EFormula E with a compound of Formula F,H2N NH2R3Formula F in the presence of a copper (I) salt and a base, thereby forming the compound ofFormula D, whereinX is a leaving group; andR3is straight-chained or branched -Cnalkyl.

[0147] In some embodiments, the leaving group comprises a halide, for example iodide.

[0148] In some embodiments, R1may be -N(R3)Cnalkyl.

[0149] In some embodiments, R2may be -N(R3)Cnalkyl.1006207079

[0150] In some embodiments, the strong acid may be selected from one or more of HCI, HPFe, H2SO4 or HBF4. Preferably, the strong acid is H2SO4. Other strong acids known in the art are contemplated.

[0151] In some embodiments, the Lewis acid is selected from BF3*Et2O. Other Lewis acids known in the art are contemplated.

[0152] Without being bound by theory, the stronger the acid used (lower pH value) the higher the conversion of the starting materials to the compounds described by the present disclosure. Improved conversion may result in higher yield or higher purity of the end product.ExamplesExample 1 - materials and methodsMaterials

[0153] Unless otherwise stated, all chemicals were used as received. 4- (diethylamino)salicylaldehyde, sulphuric acid, trifluoroacetic acid, potassium hexafluorophosphate, potassium carbonate, potassium iodide, copper iodide, potassium phosphate and 2-(2,6-dimethylphenylamino)-2-oxoacetic acid (DMPAO) were purchased from Sigma Aldrich, Merck and ChemSupply. 4’-Aminoacetophenone, 4’- lodoacetophenone, 1 -bromooctane, 1 -bromododecane, and dioctylamine were purchased from Combi-blocks. All the solvents used for the synthesis (dimethyl formamide, dimethyl sulfoxide, and acetic acid), and characterization were of analytical or HPLC grade. Kaolinite was purchased from Sigma Aldrich.

[0154] Quartz was obtained from Unimin Australia Ltd. Methyl isobutyl carbinol (98%) was purchased from Sigma Aldrich. Ethanol (analytical grade) was purchased from Thermo Fisher Scientific .Kaolinite characterization

[0155] The particle size distribution of kaolinite was measured by a particle size analyser (Malvern Mastersizer 3000). The mean value of the diameter, D[4,3], was determined by the average median value of three parallel measurements.Environmental scanning electron microscopy (ESEM) was employed using a FEI1006207079Quanta 450 ESEM to characterize the morphology of the kaolinite particles in aqueous conditions. PXRD patterns were measured at room temperature using a Bruker D8 Advance diffractometer with Cu Ka radiation (A = 1.54184 A), operated in the 20 range from 5 to 50°.Adsorption studies

[0156] Aqueous kaolinite suspensions (2.1 g / L, 475 mL) were sonicated for 1 minute and then stirred at 500 rpm for 4 minutes. Different dosages of aggregating agent (M8Flav, M12Flav, and D8Flav) dissolved in ethanol were added while keeping the ethanol concentration in each suspension at 0.6% (v / v) (Table 1). After adding the aggregating agent, the aqueous clay suspension was stirred at 200 rpm for 5 minutes at room temperature. Afterward, the supernatant was separated and centrifuged for 1 minute at 6000 rpm. The concentration of aggregating agent remaining in the supernatant was determined by absorbance measurements performed using a UV / vis spectrophotometer (Agilent Technologies Cary 60). Calibration curves were plotted and used for quantification.Table 1. Aggregating agent dosages used in the analysis expressed as pmoles of aggregating agent per 1 g of kaolinite and weight percentage of aggregating agent in each sample (weight of aggregating agent (g) per 100 g of kaolinite)1006207079Fourier transform infrared spectroscopy (FTIR)

[0157] Fourier transform infrared spectroscopy (FTIR) analysis was carried out for the kaolinite before and after adsorbing the aggregating agent. (Samples- K-1, M12Flav-8). Before the analysis, the kaolinite samples were oven dried at 60 °C for 18 hours, after treatment with the aggregating agents. The FTIR-ATR analysis was conducted (Agilent Carey 630 with diamond ATR accessory) with spectrum wavenumber ranging from 600- 4000 cm-1.X-ray diffraction analysis

[0158] X-ray diffraction analysis was performed on a Bruker D8 Advance diffractometer with Cu Ka radiation (A = 1.54184 A), operated in the 20 range from 5 to 50° and was employed for the aggregating agent (K-M8Flav-6, K-D8Flav-6, and K-M12Flav-6) samples to investigate possible structural alterations in clay resulting from the intercalation of the aggregating agent.NMR Spectroscopy

[0159] NMR spectra were recorded using a Bruker 400 Neo NMR spectrometer. Aggregating agents were dissolved in deuterated methanol at approximately 3000 ppm. The data were processed and analysed by Mnova software package.Aggregate size analysis under stirring conditions

[0160] The effect of aggregate agent concentration on the aggregate size distributions of kaolinite was evaluated by comparing different dosages from Table 1 in aqueous kaolinite suspensions (shown in Table 2 in ppm). The unbuffered kaolinite suspensions1006207079(pH 6.5) with solid concentration of 2.1 g / L (475 mL) were sonicated for 1 minute and maintained at 500 rpm stirring speed for 4 min in a baffled tank with a Rushton impeller (corresponding to 1200 s-1effective average shear rate) to homogenize the samples. Aggregating agent (Table 1) was added while stirring at 500 rpm to ensure adequate mixing, and following treatment (30 s), the stirring rate was reduced to 200 rpm (corresponding to 750 s-1effective average shear rate) and the sample was conditioned for a further 4.5 min. At this time, particle size distribution measurements were conducted using a Blaze Metrics 900 probe, which acquired high-resolution images that were then analysed computationally to derive particle sizes in the 10-700 pm range. The image plane, which relates to the distance into the suspension where the probe was focused, was set to 40 pm to achieve the best focus to ensure that aggregates were as clearly visible as possible. The probe emits a 532 nm laser beam, which captured 58 images per second. The size measurements reported are a running average of the 58 images taken every second.. A comparison with a commercial hydrophobic modifier, CTAB, was also performed. As this technique is limited to particles greater than 10 pm, the size of untreated kaolinite was determined using light scattering measurements conducted on a Mastersizer 3000. The median diameter, D50, was determined to be approximately 7.48 pmTurbidity analysis

[0161] Varying dosages of each aggregating agent from Flav-2 to Flav-6 (Table 1) were introduced into aqueous kaolinite suspensions (475 mL) which were maintained at a solid concentration of 2.1 g / L. Before aggregating agent addition, the suspensions were subjected to stirring at 500 rpm for 5 minutes in a baffled tank with a Rushton impeller. After the addition of aggregating agent, the suspension was stirred for 5 minutes, before being allowed to settle under non-stirring conditions. A syringe was used to withdraw the supernatant (10 mL) after 1 minute of settling from a depth of 1 cm below the air-liquid interface to ensure a representative sample was obtained. Before the turbidity analysis, the sample container was gently inverted three times to achieve uniform particle distribution. The turbidity was measured within two hours of collecting the sample using an AQUAfast AQ4500 turbidimeter.Table 2. Aggregating agent dosages used in the analysis expressed as pmoles of aggregating agent per 1 g of kaolinite and dosage of the aggregating agent in each sample in ppm.1006207079Surface hydrophobicity analysis

[0162] The Washburn capillary rise method was utilized to determine the wettability of the kaolinite surface before and after treatment with the aggregating agent (M12Flav,1006207079D8Flav, and M8Flav) at different concentrations from Flav-2 to Flav-6 (Table 1). The treated kaolinite powder was oven dried at 60 °C for 24 hours and then gently mixed in a closed vial to ensure homogeneity and to break any large aggregates. A clean sample tube with a filter base was filled with a known weight of powder. The sample tube was tapped about 100 times until it reached the same height at each repeating test in order to keep the powder density constant between the same sample. Each experiment was repeated three times, and the average value was taken. n-Hexane (y = 18.43 mN / m) which has a low surface tension, was used as the complete wetting liquid assuming Qadv = 0°. Distilled water was used as the test liquid. The experiment was conducted by a Force tensiometer (K100).Gravitational sedimentation analysis

[0163] The sedimentation performance of kaolinite particles under non-stirring conditions was studied in the absence and presence of aggregating agent. Different dosages of aggregating agent from Flav-2 to Flav-6 (Table 1) were added to aqueous kaolinite suspensions (1 g / L, 100 mL). Before the addition of aggregating agent, the kaolinite suspensions were stirred at 500 rpm for 5 minutes in a baffled tank with a Rushton impeller. Post aggregating agent addition, the suspensions were stirred at 200 rpm for 5 minutes and the suspensions were transferred to cylindrical glass cells and left to settle under gravity to monitor the settling behaviour. The normalized height of the solid-liquid interface was determined by expressing the interface height as a percentage of the initial height.Flotation tests

[0164] Flotation experiments were carried out at room temperature using a 500 mL laboratory scale Denver flotation cell. For each test, a total of 10.0 g of mineral (comprising 5.0 g each of kaolinite and quartz) was initially dispersed in 300 mL of KCI (0.01 M) solution within a 500 mL polypropylene vessel. The resulting mineral suspension was then transferred into the flotation cell, and additional 0.01 M KCI was added to bring the total volume to 500 mL. The impeller speed was set to 1500 rpm, and the suspension was allowed to homogenize for 1 minute. Subsequently, the aggregating agent (M12Flav) and the frother (methyl isobutyl carbinol (MIBC), dosed at 0.004% v / v) were introduced.1006207079

[0165] The aggregating agent stock solution was freshly prepared in ethanol and added to the suspension such that the final ethanol concentration was maintained at 3% v / v. Conditioning times were fixed at 3 minutes for the aggregating agent and 1 minute for MIBC. Following conditioning, flotation was initiated, and the concentrate was collected for a duration of 3 minutes. Throughout the experiments, the impeller speed (1500 rpm) and air flow rate (2 L / min) were kept constant to ensure reproducible hydrodynamic conditions. All flotation tests were conducted at the suspension’s natural pH, measured at 5.1. After flotation, both concentrate and tailing fractions were oven dried at 80 °C for four days and subsequently weighed to determine the recovery. Cumulative mass recovery (Rc) was calculated using Eq.1 and the recovery of kaolinite or quartz (RKaoi / Quartz) was calculated using Eq.2. The dosages of aggregating agent (M12Flav) used are provided in Table 3.Rc = ,mc, X 100% Eq.1 ( mc+mt) mcX PKaol / Quartz nnn / r n^Kaol / Quartz ~ r m * 100 X) Eq.2 c PKaol / QuartzyP Kaol / Quartz)

[0166] mc(g) and mt (g) are the mass of the concentrate and the tailings respectively. The ^Kaoi / Quartz (wt%) is the grade of kaolinite or quartz. The [3 Kaoi / Quartz (wt %) was determined by elemental analysis using a Bruker S2 PUMA X-ray fluorescence (XRF) spectrophotometer.

[0167] Single mineral flotation experiments were performed under comparable conditions, with and without the addition of 0.2 wt% M12Flav. Recovery values were determined according to Eq.1.Table 3. Aggregating agent dosages used in flotation experiments1006207079*Dosages are expressed as wt% of aggregating agent per 100 g of dry kaolinite.Powder x-ray diffraction (PXRD)

[0168] The powder X-ray diffraction (PXRD) patterns of kaolinite and quartz were acquired at room temperature using a Bruker D8 Advance diffractometer with Cu Ka radiation (A = 1.54184 A), operated in the 20 range from 5 to 80°.Quartz aggregate size analysis

[0169] The quartz suspension with a solid concentration of 8.4 g / L (475 mL) was sonicated for one minute and maintained at 400 rpm stirring speed for four minutes in a baffled tank with a Rushton impeller (corresponding to 975 s-1effective average shear rate) to homogenize the samples. Aggregating agent stock solution was freshly prepared in ethanol and was added (0.2% wt) to the quartz suspension while stirring (400 rpm), and conditioned at a stirring speed of 200 rpm for two minutes after aggregating agent addition.

[0170] At this time, particle size measurements were conducted using a Blaze Metrics 900 probe, which acquires high-resolution images that were then analysed computationally to derive chord length distributions in the 10-700 pm range. The image plane, which relates to the distance into suspension where the probe was focused, was set to 80 pm to achieve the best focus to ensure that aggregates were as clearly visible as possible. The probe featured a 5 mm diameter sapphire window and emitted a 532 nm laser beam, capturing 58 images per second. The reported chord length distribution values were derived from a running average of these 58 images captured every secondExample 2 - synthesis of aggregating agentsPreparation of 1-(4-octylaminophenyl)ethanone (1 in Figure 1)

[0171] To a solution of 4-aminoacetophenone (2.0 g, 14.8 mmol) in 15 mL of N,N- dimethylformamide (DMF), 1-bromooctane (5.9 g, 30.6 mmol), K2CO3 (4.1 g, 29.6 mmol), KI (5.1 g, 30.6 mmol) were added and stirred at 100 °C for 24 hours. The1006207079reaction mixture was cooled to room temperature and quenched with a mixture of ice and water. The crude product was extracted into ethyl acetate from water and was purified by passing through a column of silica gel and eluting with ethyl acetate / hexane (10 %v / v). The pure product was obtained as a pale-yellow solid with a yield of 75%. The product was identified by1H NMR. (400 MHz, CDCh) 5 (ppm) 7.81 (d, J = 8.8 Hz, 2H), 6.54 (d, J = 8.8 Hz, 2H), 4.22 (s, 1 H), 3.16 (td, J = 7.2, 3.5 Hz, 2H), 2.49 (s, 3H), 1.63 (p, J = 7.1 Hz, 2H), 5 = 1.43 - 1.25 (m, 10H), 0.89 (t, J = 6.9 Hz, 3H).Preparation of 1-(4-dodecylaminophenyl)ethanone (2 in Figure 1)

[0172] To a solution of 4-aminoacetophenone (2.0 g, 14.8 mmol) in 15 mL of N,N- dimethylformamide (DMF), 1 -bromododecane (6.3 g, 32.6 mmol), K2CO3 (4.4 g, 31.5 mmol), KI (5.3 g, 32.0 mmol) were added and stirred at 100 °C for 24 hours. The reaction mixture was cooled to room temperature and quenched with a mixture of ice and water. The crude product was extracted into ethyl acetate from water and was purified by passing through a column of silica gel and eluting with ethyl acetate / hexane (10 %v / v). The pure product was obtained as a pale-yellow solid with a yield of 70% The product was identified by1H NMR. (400 MHz, CDCh) 5 (ppm) 7.81 (d, J = 8.9 Hz, 2H), 6.54 (d, J = 8.9 Hz, 2H), 4.24 (s, 1 H), 3.16 (t, J = 7.2 Hz, 2H), 2.49 (s, 3H), 1.62 (p, J = 7.6 Hz, 2H), 1 .43 - 1 .22 (m, 20H), 0.88 (t, J = 6.6 Hz, 3H).Preparation of 1-(4-dioctylaminophenyl)ethanone (5 in Figure 1)

[0173] To a solution of 4-iodoacetophenone (2.0 g, 8.5 mmol) in 10 mL of dimethyl sulfoxide (DMSO), dioctyl amine (3.1 g, 12.75 mmol), K3PO4 (3.61 g, 17.0 mmol), Cui (0.16 g, 0.84 mmol) and DMPAO (0.33 g, 1.7 mmol) were added and stirred at 100 °C for 48 hours. The reaction mixture was cooled to room temperature and quenched with a mixture of ice and water. The crude product was extracted into ethyl acetate from water and was purified by passing through a column of silica gel and eluting with ethyl acetate / hexane (10 %v / v). The pure product was obtained as a pale-yellow oil with a yield of 50%. The product was identified by1H NMR. (400 MHz, CDCh) 5 (ppm) 7.83 (d, J = 9.03 Hz, 2H), 6.58 (d, J = 8.89 Hz, 2H), 3.31 (t, J = 7.58 Hz, 4H), 2.49 (s, 3H), 1.60 (p, J = 7.6 Hz, 4H), 1 .43 - 1.22 (m, 20H), 0.88 (t, J = 7.02 Hz, 6H).1006207079Preparation of 1, 1 '-((propane- 1, 3-diylbis(azanediyl))bis(4, 1-phenylene))bis(ethan-1-one)

[0174] To a nitrogen purged solution of 4-iodoacetophenone (2.5 g, 10.2 mmol) in 100 mL of anhydrous dimethylformamide (DMF), L-proline (234 mg, 2.0 mmol), K2CO3 (2.809 g, 20.3 mmol), Cui (194 mg, 1.0 mmol) and 1 ,3-diaminopropane (385.6 pL, 4.6 mmol) were added and stirred at 80 °C for 40 hours. The reaction mixture was cooled to room temperature, filtered and quenched with water. The crude product was extracted into ethyl acetate from water and was purified by passing through a column of silica gel and eluting with ethyl acetate / hexane (10 %v / v). The pure product was obtained as a colourless solid with a yield of 18%. The product was identified by1H NMR. (400 MHz, CDCI3) 5 (ppm) 7.83 (d, J = 8.79 Hz, 4H), 6.57 (d, J = 8.85 Hz, 4H), 4.24 (t, J = 5.31 Hz, 2H), 3.35 (td, J = 6.72, 5.63 Hz, 4H), 2.50 (s, 6iH), 2.00 (p, J = 6.86 Hz, 2H). Mass spectrum for Chemical Formula: CigH22N2O2Na1+m / z: 333.1569.Preparation of 1-(4-( (3-( (4-acetyl phenyl) (octyl)amino)propyl)amino)phenyl)ethan- 1-one

[0175] To a solution of 1 ,1'-((propane-1 ,3-diylbis(azanediyl))bis(4,1- phenylene))bis(ethan-1-one (60 mg, 0.19 mmol) in 2 mL of acetonitrile, 1 -bromooctane (134 pL, 0.58 mmol) and CS2CO3 (189 mg, 0.58 mmol) were added and stirred at 82 °C for 48 hours. The reaction mixture was cooled to room temperature and quenched with water. The crude product was extracted into ethyl acetate from water and was purified by passing through a column of silica gel and eluting with ethyl acetate / hexane (10 %v / v). The pure product was obtained as a pale-yellow solid with a yield of 18%. The product was identified by1H NMR. (400 MHz, CDCI3) 5 (ppm) 7.83 (dd, J = 8.9, 2.2 Hz,10062070794H), 6.61 (d, J = 9.0 Hz, 2H), 6.56 (d, J = 8.6 Hz, 2H), 4.19 (s, 1 H), 3.49 (t, J = 7.2 Hz, 2H), 3.33 (t, J = 7.6 Hz, 2H), 3.27 (m, 2H), 2.50 (s, 3H), 2.49 (s, 3H), 1.97 (p, J = 7.0 Hz, 2H), 1.59 (m, J = 7.0 Hz, 2H), 1.27 (m, 10H), 0.88 (t, J = 6.6 Hz, 3H). Mass spectrum for Chemical Formula: C27H3sN2O2Na1+m / z: 445.2820.Preparation of N 1, N8-diphenyloctane- 1, 8-diamine

[0176] To a solution of 1 ,8-dibromooctane (5.03 mL, 27.4 mmol) in aniline (10.0 mL, 110 mmol), K2CO3 (7.56 g, 54.8 mmol) and KI (910 mg, 5.5 mmol) were added and stirred at 80 °C for 18 hours. The crude product was extracted to ethyl acetate from water and was purified by passing through a column of silica gel and eluting with ethyl acetate / hexane (10 %v / v). The pure product was obtained as a colourless solid with a yield of 67%. The product was identified by1H NMR. (400 MHz, CDCI3) 5 (ppm) 7.29 (m, 4H), 6.81 (tt, J = 7.3, 1.1 Hz, 2H), 6.78 - 6.68 (m, 4H), 3.66 (s, 2H), 3.19 (td, J = 7.1 , 1.7 Hz, 4H), 1.71 (m, 4H), 1.46 (m, 8H). Mass spectrum for Chemical Formula: C2OH29N21+m / z: 297.2312.Preparation of N 1, N8-dioctyl-N 1, N8-diphenyloctane- 1, 8-diamine

[0177] To a solution of N1 ,N8-diphenyloctane-1 , 8-diamine (148 mg, 0.5 mmol), 1 ,- bromooctane (256 pL, 1.5 mmol), K2CO3 (207 mg, 1.5 mmol) and KI (249 mg, 1.5 mmol) were added in DMF (4 mL) and stirred at 100 °C for 20 hours. The crude product was extracted into ethyl acetate from water and was purified by passing through a1006207079column of silica gel and eluting with ethyl acetate / hexane (2 %v / v). The pure product was obtained as a colourless oil with a yield of 77%. The product was identified by1H NMR. (400 MHz, CDCh) 5 (ppm) 7.34 (dd, J = 8.8, 7.1 Hz, 4H), 6.78 (m, 6H), 3.39 (m, 8H), 1.73 (m, 8H), 1.47 (m, 28H), 1.05 (m, 6H). Mass spectrum for Chemical Formula: C36H6ON21+m / z: 521.4845.Preparation of 1, 1 '-((octane-1, 8-diylbis(octylazanediyl))bis(4, 1-phenylene))bis(ethan-1- one)

[0178] To a solution of N1 ,N8-dioctyl-N1 ,N8-diphenyloctane-1 ,8-diamine (1.75 g, 3.4 mmol), aluminium chloride (1.35 g, 10.1 mmol) and acetyl chloride (0.72 mL, 10.1 mmol) were added in anhydrous dichloromethane (30 mL) at 0 °C and stirred at room temperature for 20 hours. The crude product was quenched in ice water, filtered and extracted into dichloromethane from water and was purified by passing through a column of silica gel and eluting with ethyl acetate / hexane (20 %v / v). The pure product was obtained as a pale yellow solid with a yield of 1%. The product was identified by1H NMR. (400 MHz, CDCh) 5 (ppm) 7.82 (d, J = 9.1 Hz, 4H), 6.57 (d, J = 9.2 Hz, 4H), 3.31 (t, J = 7.8 Hz, 8H), 2.48 (s, 6H), 1.65 (m, 8H), 1.58 (m, 28H) 1.13 (m, 6H). Mass spectrum for Chemical Formula: C4oH6sN2C>21+m / z: 605.5037.Preparation of 7-diethylamino-4'-octylaminoflavylium hexafluorophosphate (6 in Figure 1) - M8Flav

[0179] 4-(diethylamino)salicylaldehyde (1.7 g, 8.7 mmol) and 4-N- octylaminoacetophenone (2.1 g, 8.4 mmol) were dissolved in glacial acetic acid (8 mL) and concentrated sulphuric acid (1.5 mL). The reaction was allowed to proceed for 18 hours at room temperature. The product was extracted into dichloromethane (DCM) as1006207079a hydrogen sulphate salt and washed with water. Afterward, the product was purified by passing through a column of silica in acidic conditions using ethyl acetate / hexane (20 %v / v), and the pure flavylium was recovered from the fraction eluted with methanol / DCM (10 %v / v). Anion exchange was carried out by adding potassium hexafluorophosphate into flavylium dissolved in ethyl acetate, followed by crystallization in a mixture of ethyl acetate / hexane (1 :1) to yield metallic green colour needle-shaped crystals of flavylium hexafluorophosphate with a yield of 50%. The product was identified by1H NMR, (400 MHz, MeOD) 5 (ppm) 8.31 (d, J = 8.6 Hz, 1 H), 8.12 (d, J = 9.2 Hz, 2H), 7.74 (d, J = 9.2 Hz, 1 H), 7.63 (d, J = 8.7 Hz, 1 H), 7.21 (dd, J = 9.3, 2.5 Hz, 1 H), 7.07 (d, J = 2.4 Hz, 1 H), 6.79 (d, J = 9.0 Hz, 2H), 3.67 (q, J = 7.1 Hz, 4H), 3.36 - 3.24 (m, 8H, overlapped with the solvent peak), 1.68 (p, J = 7.2 Hz, 2H), 1.49 - 1 .25 (m, 18H), 0.95 - 0.87 (m, 3H). Mass spectrum of M8Flav: Chemical Formula: C27H37N2O+ m / z: 405.29, 406.29 , 407.30. Elemental analysis (%) calculated for C27H37N2OPF6: C 58.90, H 6.77, N 5.09: found: C 58.93, H 6.74, N 5.0. The purity of the crystals was evaluated by comparing the experimental powder XRD pattern with the simulated pattern derived from the single crystal XRD data. The experimental pattern closely matched the simulated pattern which suggested good crystal purity.). TGA analysis confirmed that the M8Flav was free of solvents in its crystal structure and remained thermally stable up to 200°C.Preparation of 7-diethylamino-4'-dodecylaminoflavylium hexafluorophosphate (7 in Figure 1) - M12FlavThe same procedure as mentioned above for 7-diethylamino-4'-octylaminoflavylium hexafluorophosphate was carried out by mixing 4-(diethylamino)salicylaldehyde (1.7 g, 8.7 mmol) and 4-N-dodecylaminoacetophenone (2.6 g, 8.6 mmol) in glacial acetic acid (8 mL) and concentrated sulphuric acid (1.5 mL). The reaction was allowed to proceed for 18 hours at room temperature. After the purification and anion exchange process, pure flavylium hexafluorophosphate was obtained as green metallic colour needle- shaped crystals with a yield of 35%. The product was identified by1H NMR, (400 MHz, MeOD) 5 (ppm) 8.22 (m, 1 H), 7.97 (m, 2H), 7.64 (m, 1 H), 7.51 (m, 1 H), 7.10 (m, 1 H), 6.92 (m, 1 H), 6.69 (m, 2H), 3.58 (m, 4H), 3.17 (m, 2H), 1.61 (p, J = 7.0 Hz, 2H), 1.31 (m, 27H), 0.84 (t, J = 6.6 Hz, 3H). Elemental analysis (%) calculated for C31H45N2OPF6: C 61.37, H 7.48, N 4.62: found: C 61.59, H 7.42, N 4.61. The purity of the crystals was evaluated by comparing the experimental powder XRD pattern with the simulated1006207079pattern derived from the single crystal XRD data. The experimental pattern closely matched the simulated pattern, which suggested good crystal purity. TGA analysis confirmed that the M12Flav was free of solvents in its crystal structure and remained thermally stable up to 200°C.Preparation of 7-diethylamino-4'-dioctylaminoflavylium trifluoroacetate (10 in Figure 1) - D8Flav

[0180] 4-(Diethylamino)salicylaldehyde (1.7 g, 8.7 mmol) and 4-N,N- dioctylaminoacetophenone (3.1 g, 8.6 mmol) was dissolved in glacial acetic acid (8 mL) and concentrated sulphuric acid (1.5 mL). The reaction was allowed to proceed for 18 hours at room temperature. The product was extracted to dichloromethane (DCM) as a hydrogen sulphate salt and washed with water. Afterward, the product was purified by passing through a column of silica in acidic conditions using ethyl acetate / hexane (20 %v / v), and the pure flavylium was recovered from the fraction eluted with methanol / DCM (10 %v / v). Anion exchange was carried out by adding trifluoroacetic acid into flavylium dissolved in methanol, followed by crystallization in a mixture of methanol / water (1 :1) to yield metallic green colour needle-shaped crystals of flavylium trifluoroacetate with a yield of 35%. The product was identified by1H NMR, (400 MHz, MeOD) 5 (ppm) 8.34 (d, J = 8.6 Hz, 1 H), 8.18 (d, J = 9.3 Hz, 2H), 7.77 (d, J = 9.2 Hz, 1 H), 7.67 (d, J = 8.6 Hz, 1 H), 7.24 (dd, J = 9.2, 2.5 Hz, 1 H), 7.09 (d, J = 2.4 Hz, 1 H), 6.92 (d, 2H), 3.69 (q, J = 7.1 Hz, 4H), 3.57 - 3.50 (m, 4H), 1.74 - 1.64 (m, 4H), 1.45 - 1.27 (m, 27H), 0.94 - 0.87 (m, 6H). Mass spectrum of D8Flav: Chemical Formula: C35H53N2O+ m / z: 517.42, 518.42, 519.42. TGA analysis revealed that D8Flav contained 5.76% solvent, consistent with single-crystal data that identified a similar proportion of hexane incorporated within the crystal structure. Additionally, D8Flav exhibited thermal stability up to 160°C.Preparation of 2,2'-((propane- 1,3-diylbis(azanediyl))bis(4, 1-phenylene))bis(7- (diethylamino) chromenylium) hexafluorophosphate1006207079

[0181] 4-(diethylamino)salicylaldehyde (1.145 g, 5.93 mmol) and 1 ,1'-((propane-1 ,3- diylbis(azanediyl))bis(4,1-phenylene))bis(ethan-1-one) (0.46 g, 1.48 mmol) were dissolved in glacial acetic acid (15 mL) and concentrated sulphuric acid (3.0 mL). The reaction was allowed to proceed for 18 hours at room temperature. The product was extracted into 10 % v / v methanol in dichloromethane (DCM) with 1% v / v trifluoroacetic acid (TFA) as a trifluoroacetate salt and washed with 1% v / v TFA in water. Afterward, the product was purified by passing through a column of silica in acidic conditions using methanol / dichloromethane (10 %v / v), and the pure flavylium was recovered from the fraction eluted with methanol / DCM (10 %v / v) with a yield of 16%. Anion exchange was carried out by adding potassium hexafluorophosphate into flavylium dissolved in methanol, followed by crystallization in a mixture of methanol / dichloromethane (1:1) to yield metallic green colour needle-shaped crystals of flavylium hexafluorophosphate. The product was identified by1H NMR, (400 MHz, MeOD) 5 (ppm) 8.18 (d, J = 8.6 Hz, 2H), 7.97 (d, J = 9.2 Hz, 4H), 7.63 (d, J = 9.3 Hz, 2H), 7.53 (d, J = 8.6 Hz, 2H), 7.13 (dd, J = 9.3, 2.4 Hz, 2H), 6.89 (d, J = 2.2 Hz, 2H), 6.74 (d, J = 9.2 Hz, 4H), 3.63 (q, J = 7.2 Hz, 8H), 3.45 (t, J = 6.5 Hz, 4H), 2.04 (p, J = 6.6 Hz, 2H), 1.30 (t, J = 6.6 Hz, 12H). Mass spectrum for Chemical Formula: C4iH46N4C>22+m / z: 313.1801.Preparation of 7-(diethylamino)-2-(4-((3-((4-(7-(diethylamino)chromenylium-2- yl)phenyl)(octyl)amino)propyl)amino)phenyl)chromenylium trifluoroacetate

[0182] 4-(diethylamino)salicylaldehyde (9 mg, mmol) and 1-(4-((3-((4- acetylphenyl)(octyl)amino)propyl)amino)phenyl)ethan-1-one (5 mg, mmol) were dissolved in glacial acetic acid (1 mL) and concentrated sulphuric acid (6 drops). The reaction was allowed to proceed for 48 hours at room temperature. The product was extracted into 10 % v / v methanol in dichloromethane (DCM) with 1% v / v trifluoroacetic acid (TFA) as a trifluoroacetate salt and washed with 1% v / v TFA in water. Afterward,1006207079the product was purified by passing through a column of silica in acidic conditions using methanol / dichloromethane (10 %v / v), and the pure flavylium was recovered from the fraction eluted with methanol / DCM (10 %v / v) with a yield of 26%. The product was identified by1H NMR, (400 MHz, MeOD) 5 (ppm) 8.25 (dd, J = 8.6, 3.9 Hz, 2H), 8.06 (m, 4H), 7.72 (d, J = 9.2 Hz, 1 H), 7.65 (d, J = 9.3 Hz, 1 H), 7.61 (dd, J = 8.6, 6.4 Hz, 2H), 7.22 (dd, J = 9.3, 2.4 Hz, 1 H), 7.16 (dd, J = 9.3, 2.4 Hz, 1 H), 7.00 (t, J = 2.5 Hz, 2H), 6.94 (d, J = 9.3 Hz, 2H), 6.77 (d, J = 9.0 Hz, 2H), 4.58 (s, 1 H), 3.75 (t, J = 7.0 Hz, 2H), 3.66 (p, J = 7.2 Hz, 8H), 3.57 (t, J = 7.7 Hz, 2H), 3.42 (t, J = 6.4 Hz, 2H), 2.11 (p, J = 6.6 Hz, 2H), 1.68 (m, 2H), 1.30 (m, 22H), 0.88 (t, J = 6.4 Hz, 3H). Mass spectrum for Chemical Formula: C49HeiN4O21+m / z: 737.4797.Preparation of 2,2'-((octane- 1, 8-diylbis(octylazanediyl))bis(4, 1 -phenylene)) bis(7- (diethylamino) chromenylium) trifluoroacetate

[0183] 4-(diethylamino)salicylaldehyde (20.4 mg, 0.11 mmol) and 1 ,1'-((octane-1 ,8- diylbis(octylazanediyl))bis(4,1-phenylene))bis(ethan-1-one) (16 mg, 0.03 mmol) were dissolved in glacial acetic acid (0.5 mL) and concentrated sulphuric acid (10 drops). The reaction was allowed to proceed for 48 hours at room temperature. The product was extracted into 10 % v / v methanol in dichloromethane (DCM) with 1 % v / v trifluoroacetic acid (TFA) as a trifluoroacetate salt and washed with 1 % v / v TFA in water. Afterward, the product was purified by passing through a column of silica in acidic conditions using methanol / dichloromethane (10 %v / v), and the pure flavylium was recovered from the fraction eluted with methanol / DCM (10 %v / v) with a yield of 3%. The product was identified by1H NMR, (400 MHz, MeOD) 5 (ppm) 8.32 (d, J = 8.6 Hz, 2H), 8.15 (d, J = 9.3 Hz, 4H), 7.75 (d, J = 9.3 Hz, 2H), 7.63 (d, J = 8.7 Hz, 2H), 7.22 (dd, J = 9.3, 2.5 Hz, 2H), 7.05 (d, J = 2.3 Hz, 2H), 6.91 (d, J = 9.4 Hz, 4H), 3.67 (q, J = 7.1 Hz, 8H), 3.53 (m,10062070798H), 1.69 (m, 8H), 1.30 (m, 36H), 0.90 (m, 6H). Mass spectrum for Chemical Formula: C62H88N4O22+m / z: 460.3453.Example 3 - Characterisation of Kaolinite

[0184] The initial particle size distribution of kaolinite was analysed. The mean diameter, D[4,3], was determined to be 10.1 pm, calculated as the average median value from three parallel measurements. Additional size parameters include D [3,2]: 4.82 pm, D10: 2.35 pm, D50: 7.48 pm, D90: 21.6 pm. The solid concentration was recorded at 0.01 %, with a span of 2.566, uniformity of 0.798, and a specific surface area of 1244 m2 / kg.

[0185] Environmental scanning electron microscopy (ESEM) was employed to investigate the morphology of kaolinite particles under 100% humid conditions at room temperature. Before treatment with the aggregating agent, the particles exhibited a predominantly uniform orientation of stacked clay sheets with face-to-face arrangements.

[0186] The X-ray diffraction (XRD) pattern of the kaolinite sample revealed several distinctive peaks indicative of its mineralogical identity. The most prominent peak at 12.36° 20 (7.14 A) corresponds to the (001) plane, which reflects the basal spacing of the kaolinite layers. Additionally, a peak at 24.84° 20 (3.57 A) was observed, associated with the (002) plane. Further support for the presence of kaolinite was provided by peaks at 20.04° 20 (4.43 A) and 38.40° 20 (2.34 A).Example 4 - Adsorption studies

[0187] Based on the absorbance measurements of the supernatants (as described in Table 1), it was observed that all the aggregating agent present in the solution was effectively adsorbed onto kaolinite within the dosage range from Flav 2 to Flav 5 after five minute conditioning periods. Beyond the dosage level of Flav 5, the adsorption behaviour varied among different types of Flavs. M8Flav and D8Flav exhibited a consistent adsorption trend that followed an approximately linear relationship with increasing dosage, indicating a proportional increase in adsorption. In contrast, M12Flav approached saturation, as evidenced by a plateau in its adsorption capacity beyond this dosage level. This suggests that the adsorption sites on kaolinite for M12Flav were1006207079becoming fully occupied, thereby limiting further adsorption with higher dosages (Figure 3).

[0188] Based on the powder X-ray diffraction (XRD) measurements, the d-spacing of kaolinite clay did not show significant alterations upon adsorption of the aggregating agents. This observation suggests that these molecules likely interact with the external surface of the kaolinite particles rather than intercalating into the interlayer spaces. However, the d-spacing may remain unchanged even if intercalation occurs, particularly for molecules with small dimensions that might not significantly alter the interlayer distance.

[0189] The FTIR spectrum of kaolinite (K1) before treatment with aggregating agent, (Figure 4 (a)) shows the characteristic absorption bands of kaolinite. The well-defined adsorption bands at 3683.4 cm1, 3651.8 cm-1and 3620.6 cm-1correspond to the ordered structure of kaolinite and the stretching frequencies of OH groups. Two of them at 3683.4 cm-1, and 3651.8 cm-1were attributed to the stretching modes of the outer Al- OH groups, and the band at 3620.6 cm-1was attributed to the stretching of inner AI-OH groups. The bands observed at 1114.0, 1023.8, and 994.0 cm-1are attributed to the Si- O-Si stretching vibrations. The AI-OH bending vibrations were observed at 910.3 and 936.1 cm-1. The band at 788.2 cm-1could be attributed to the Si-O-AI stretching vibrations.

[0190] M12Flav adsorbed kaolinite (K-M12Flav-8) showed the characteristic peaks of M12Flav in the FTIR spectrum (Figure 4-(c)). In the IR spectrum of M12Flav, symmetric and asymmetric C-H stretching vibrations of alkyl chains were observed at 2921.2 and 2851.5 cm-1. The bands at 1637.4, 1607.5, 1551.9, and 1498.0 cm-1were assigned to 0=0 stretching in benzopyrylium and phenyl rings. A few medium bands around 1446 cm-1could be attributed to the C-H bending vibrations. The band at 1403.6 cm-1was assigned to the C-0 stretching in the benzopyrylium ring. The bands at 1334.2 and 1243.3 cm-1were assigned to the C-N stretching vibrations. The medium band between 1200-1000 cm-1was related to C-C and C-0 deformations in the pyrylium ring. After adsorption onto kaolinite, the shifts in the C-N stretching vibrations of M12Flav from 1334 cm-1to 1349 cm-1and from 1243 cm-1to 1246 cm-1in the FTIR spectrum (Figure 4(b)) could indicate an interaction between M12Flav and the kaolinite surface. However, the increase in wavenumber correspond to a stronger C-N bond, which may result from breaking the ion pair H--F interactions in M12Flav with counter ion, resulting in greater1006207079positive charge delocalization. This evidence supports electrostatic interactions being the dominant interactions between M12Flav and kaolinite surface rather than hydrogen bonding. However, it does not rule out hydrogen bonding interactions with the surface, it only suggests that they are weaker than those observed in crystal structures.

[0191] The single crystal structures of M12Flav, M8Flav, and D8Flav (Figure 5) illustrate that the alkyl chains of these molecules can adopt different orientations potentially extending in multiple directions. According to the bond length values obtained from the crystal structures, the C-N bonds show double bond characteristics, likely attributed to their delocalized positive charge. The C-C bond between the benzopyrylium and the benzene ring exhibits single bond characteristics, facilitating torsional twisting of the benzene ring. Based on the characteristics of these molecules, it is hypothesized that the positively charged oxonium moiety may interact with the electronegative surface of kaolinite. Additionally, hydrogen bonds can be formed between the H-atoms of the hydroxyl surface of kaolinite and the N-atom of the two amine groups. The H-atom attached to the secondary amine in M12Flav and M8Flav could also form hydrogen bonds with O-atoms in both silicate and aluminol (hydroxylated alumina) surfaces, which may facilitate the tilting of the benzene ring and extend the alkyl chains outwards the kaolinite surface.Example 5 - Real-time aggregate size measurements under stirring conditions

[0192] Focused beam reflectance measurements were taken by Blaze probe, which is an image derived chord length distribution measuring technique, to obtain real time edge to edge chord length distribution of aggregates. In this method, the number of chords measured is proportional to their probability in Blaze chord length distribution measurements. For instance, the shorter chords at the edges of a sphere, have a lower probability as there is less area compared to those near the diameter as there is more area, hence a greater probability of measurements. All the chord measurements in the Blaze probe are weighted by their chord length for this reason and the data is innately length weighted. The length-weighted measurements provided insight into the changes in the small particles or aggregates in the system. Once the small particles or aggregates formed larger aggregates, the number of measured chords (counts) for a given chord length changed accordingly. The cube-weighted (CW) chord length distribution is the number of counts at each chord length multiplied by the square of its1006207079length, and it is more closely related to the volume-based particle size distribution. This gave insight into aggregation more effectively. The cube-weighted chord length distribution shifts toward larger chord lengths, with an increase in counts as the aggregate size increases.

[0193] Length-weighted chord length distributions are more sensitive to the smaller particles or aggregates present in the suspension and show how the increment in the aggregating agent dosage from Flav-2 to Flav-6 (Table 1) affected the progressive reduction in counts, with some evidence of an increase in aggregate size (Figure 6, (a)). Cube-weighted chord length distribution gave more insight into the larger aggregate size, and it showed a peak shift to larger chord length values as the dosage was increased from Flav-2 to Flav-5 (Figure 6 (b)). At the highest dosage considered (Flav-6), the chord length distributions of all three aggregating agents deviated from the expected trend, which typically showed an increase in cube-weighted chord length counts while increasing aggregating agent dosage. This decrease in the aggregate sizes may be attributed to the restabilisation of the colloidal suspension, due to the formation of aggregating agent multilayer coating on the clay particles, which leads to enhanced electrostatic repulsion between particles. This suggested that the system had exceeded the optimum dosage required for the effective aggregation.

[0194] At higher dosages, the median cube-weighted chord lengths of kaolinite aggregates formed by M12Flav were larger compared to those formed by D8Flav and M8Flav (Figure 7 (a)). Conversely, at lower dosages, D8Flav resulted in larger median cube-weighted chord lengths than M12Flav and M8Flav. M8Flav formed smaller aggregates, which could be explained by the presence of a shorter alkyl chain, which leads to the formation of smaller or less stable aggregates at the shear conditions used. Both M12Flav and D8Flav showed considerably larger aggregate sizes, likely due to the presence of long or dual alkyl chains. CTAB resulted in smaller kaolinite aggregates, indicating that the presently disclosed aggregating agents are more efficient in promoting larger aggregate formation. The real-time images of the particles showing the size and morphology of kaolinite before and after treatment with D8Flavand M12Flav are presented in Figures 8 and 9.1006207079Example 6 - Surface hydrophobicity analysis

[0195] The Washburn capillary rise method was employed to assess the wettability of Flav-treated and untreated kaolinite powder. This method assumes that the porous powder materials can be conceptualised as a collection of parallel capillaries with constant radius. The Washburn equation, which delineates a linear relationship between the squared mass (m2) and the measurement time (t), was used to determine the contact angles of kaolinite. 0 = contact angle, C = capillary constant of the powder, p = density of the liquid, q = viscosity of the liquid, yi = surface tension of the liquid, m2 / t = slope of the curve. The slope of the wetting curves of kaolinite with distilled water and n- hexane was used to calculate the contact angle by using the Washburn equation.Cos 0adv = T] / (Cp2yi) *m2 / t

[0196] The capillary constant is contingent upon the geometry and characteristics of the capillary network within the porous material. These parameters determine the rate at which liquid ascends the capillary network and is influenced by factors such as pore size distribution, surface chemistry, and structure of the porous material. Therefore, a variation in the capillary constants across the samples was observed due to the discrepancies in particle size and surface hydrophobicity resulting from the surface adsorption of the aggregating agent. The initial contact angle of kaolinite (K-1) measured was around 60°and upon treatment with 1.735 pmoles / L of aggregating agent the contact angle of kaolinite with water rapidly increased (77.08° with M8Flav, 78.19° with M12Flav and 83.24° with D8Flav) and exhibited a continual rise, before reaching a plateau at even higher dosages (Figure 10). At low dosages (Flav-2 to Flav- 3), kaolinite treated with D8Flav, M12Flav, and M8Flav exhibited contact angle values in decreasing order, which might be explained by the combined effect of the length and the number of alkyl chains. At higher dosages (Flav-4 to Flav-6), all the aggregate agent-treated kaolinite showed approximately similar contact angle values, presumably due to the surface saturation of kaolinite by the aggregating agent. D8Flav may be inclined to interact predominantly with the negatively charged siloxane surface via electrostatic interactions, while M12Flav exhibits interactions with both surfaces including the aluminol (hydroxylated alumina) surface, forming stronger hydrogen bonds. For these three aggregating agents it is proposed that the presence of a distributed positive charge on a planar aromatic structure due to the electron donor-1006207079acceptor nature of these molecules facilitates strong and stable electrostatic interactions with the negatively charged planar siloxane surface of kaolinite. Moreover, the amine nitrogens attached to the cationic flavylium moiety may form hydrogen bonds with the hydroxyl groups on the kaolinite surface(Figure 5).Example 7 - Gravitational sedimentation analysis

[0197] A series of cylinder settling experiments were conducted to evaluate the sedimentation performance of kaolinite with M8Flav, M12Flav and D8Flav at the same concentration. This method is widely employed to study and evaluate the settling rate of aggregates. The main objective of these tests was to obtain a general idea of the fundamental effect of aggregating agent type and concentration on the settling efficiency of kaolinite.

[0198] The treatment of kaolinite with aggregating agent resulted in enhanced settling rates and improved supernatant clarity compared to untreated kaolinite (K-1) (Figure 11). Increasing the dosage of M12Flav, led to a pronounced enhancement in settling rate and the clarity of the supernatant.Example 8 - Froth flotation

[0199] An exemplary aggregating agent of the present disclosure (M12Flav) was investigated for its ability to promote selective flotation of kaolinite from a synthetic 1 :1 kaolinite-quartz mixture. Elemental analysis was performed using X-ray fluorescence (XRF), while powder X-ray diffraction (PXRD) was used for quantitative phase identification of the flotation fractions. The Blaze Probe technique was employed to assess quartz aggregate size distribution in situ, providing insight into particle interactions induced by the aggregating agent.

[0200] PXRD spectra of pure kaolinite and quartz were recorded, and characteristic peaks corresponding to each phase were identified. For quantitative analysis, the most intense and well resolved diffraction peaks of kaolinite (d001 at 20 » 12.4°) and quartz (d101 at 20 » 26.7°) were selected (Figure 12(a)). The PXRD patterns of the initial kaolinite-quartz mixture (1 :1 by weight), was compared with the diffraction patterns of concentrate and tailings fractions obtained at each aggregating agent dosage (Figure 12(b)) to evaluate the mineralogical separation achieved through flotation. In the feed sample, characteristic diffraction peaks of both kaolinite and quartz were observed, with1006207079prominent reflections at around 12.4° 20 (kaolinite) and 26.7° 20 (quartz), showing a ratio between the peak integrations of kaolinite and quartz (001 / 101) at around 0.65.

[0201] In the absence of the aggregating agent, the flotation process resulted in an increase in the peak integration ratio (IR) of the concentrate to 1.195, indicating a slight unintended flotation of kaolinite. Conversely, the IR of the tailings was reduced to 0.51, suggesting that a substantial fraction of kaolinite remained in the tailings. These results imply that, under these conditions, kaolinite exhibits a degree of natural floatability. When flotation was conducted in the presence of the aggregating agent, the peak integration ratio (IR) of the concentrate fractions increased while that of the tailings decreased (Figure 13). Increasing the aggregating agent dosage up to 0.1 wt% led to a maximum separation, with the IR reaching 3.32 in the concentrate and 0.29 in the tailings, indicating effective separation between kaolinite and quartz. However, further increases in the aggregating agent dosage caused a decline of the IR in the concentrate. This behaviour, coupled with the observed increase in cumulative mass recovery, suggests that beyond a certain aggregating agent concentration (approximately 0.1 %wt M12Flav dosage), M12Flav begins to promote flotation of quartz as well, diminishing the selectivity and efficacy of kaolinite-quartz separation.

[0202] XRF analysis of the flotation fractions indicated that kaolinite recovery increased sharply, reaching approximately 70%, and then levelled off at around 0.2%wt of aggregating agent dosage. The kaolinite grade in the concentrate increased at low dosages but showed a slight decline at higher dosages. Consistent with the PXRD analysis, quartz was recovered to some extent across all aggregating agent dosages, with its flotation increasing notably beyond 0.1 %wt, indicating a reduced kaolinite grade in the concentrate fraction (Figure 14).

[0203] In the absence of the aggregating agent, quartz exhibited limited floatability, with a recovery of only 7.6%. However, upon the addition of 0.2 wt% M12Flav, quartz recovery increased markedly to 79.8%.Example 9 - Quartz aggregate size analysis

[0204] The macroscopic impact on particle-particle interactions following aggregating agent adsorption was analysed through particle size analysis using the Blaze probe technique. While this is unable to distinguish between particles smaller than 10 pm, it1006207079effectively characterizes the coarser fraction and aggregation behaviour. Analysis of the chord length distribution profiles within the measurable range revealed significant shifts in length-weighted and cube-weighted counts of quartz particle suspensions after M12Flav addition, indicating aggregation.

[0205] This method utilizes length-weighted chord length distributions to better resolve finer particle distributions, while cube-weighted distributions give more insight into the larger aggregates in the system. Following the addition of M12Flav, the length-weighted and cube-weighted chord length distributions of quartz exhibited a shift towards larger aggregates, accompanied by a decrease in overall length-weighted counts and an increase in cube-weighted counts (Figure 15). Treatment with M12Flav resulted in an increase in the median cube-weighted particle size of the quartz from 26.7 pm to 139.8 pm. Images of quartz particles captured in situ within the shear cell, both prior to and following treatment with M12Flav (0.2%wt), indicated that the aggregating agent induces aggregation of quartz particles.1006207079

Claims

CLAIMS1. A method of aggregating particles of anionic gangue in an aqueous anionic gangue suspension, the method comprising contacting the aqueous anionic gangue suspension with an aggregating agent, thereby forming an anionic gangue aggregating agent composite, wherein the aggregating agent comprises at least one polycyclic oxonium arene core substituted with at least one substituent comprising a linear or branched alkyl chain, said alkyl chain having a chain length of at least 6 carbon atoms.

2. A method of concentrating particles of anionic gangue in an aqueous anionic gangue suspension, the method comprising subjecting the anionic gangue aggregating agent composite formed by the method according to claim 1 to one or more physical separation processes.

3. The method according to claim 2, wherein the one or more physical separation processes comprise one or more of filtration, evaporation, centrifugation, sedimentation and froth flotation.

4. A composite comprising particles of anionic gangue and an aggregating agent, said aggregating agent comprising at least one polycyclic oxonium arene core substituted with at least one substituent comprising a linear or branched alkyl chain, said alkyl chain having a chain length of at least 6 carbon atoms.

5. The method according to claim 1 or claim 2, wherein the concentration of aggregating agent in the aqueous anionic gangue suspension is from about 0.2 ppm to about 200 ppm, ppm defined as weight / volume.

6. The method according to any one of claims 1 to 3 or 5, or the composite according to claim 4, wherein the amount of aggregating agent to anionic gangue is from about 0.1 pmol to about 100 pmol of aggregating agent per gram of anionic gangue.

7. The method according to any one of claims 1 to 3, 5 or 6, or the composite according to claim 4 or claim 6, wherein the particles of anionic gangue have a mean diameter from about 5 pm to about 100 pm, or from about 5 pm to about 50 pm, or from about 5 pm and about 15 pm.10062070798. The method according to any one of claims 1 to 3 or 5 to 7, or the composite according to any one of claims 4, 6 or 7, wherein the particles of anionic gangue are constituents of a mineral mixture or mineral tailings.

9. The method according to any one of claims 1 to 3 or 5 to 8, or the composite according to any one of claims 4 or 6 to 8, wherein the anionic gangue comprises one or more of silica (for example, quartz), clay, carbonate, sulphate, or phosphate.

10. The method or composite according to claim 9, wherein the clay comprises one or more of kaolinite, illite, smectite and vermiculite, and / or the silica comprises quartz.

11. A method of selectively aggregating particles of clay from particles of quartz, the method comprising contacting an aqueous suspension comprising clay and quartz particles with an aggregating agent, wherein the aggregating agent is in an amount sufficient to form a clay aggregating agent composite, thereby selectively aggregating the particles of clay from the particles of quartz, and wherein the aggregating agent comprises at least one polycyclic oxonium arene core substituted with at least one substituent comprising a linear or branched alkyl chain, said alkyl chain having a chain length of at least 6 carbon atoms.

12. The method according to any one of claims 1 to 3, or 5 to 11 , or the composite according to any one of claims 4 or 6 to 10, wherein the at least one substituent comprising a linear or branched alkyl chain is attached directly to the polycyclic oxonium arene core.

13. The method according to any one of claims 1 to 3 or 5 to 11 , or the composite according to any one of claims 4 or 6 to 10, wherein the at least one substituent comprising a linear or branched alkyl chain is attached to the polycyclic oxonium arene core through a heteroatom, through an arene ring, or a combination thereof.

14. The method or composite according to claim 13, wherein the heteroatom is selected from the group consisting of O, N and S.100620707915. The method according to any one of claims 1 to 3 or 5 to 11 , or the composite according to any one of claims 4 or 6 to 10, wherein the aggregating agent is a compound of Formula (I) or a salt thereof:Formula (I), wherein,X- is an anion;L is an aryl group, or a covalent bond between the oxonium arene and R1;R1and R2are independently selected from -Cnalkyl, -OCnalkyl and -N(R3)Cnalkyl;R3is selected from H and -Cnalkyl; in at least one instance n is a number greater than or equal to 6; and wherein the alkyl groups are independently straight-chained or branched.

16. The method according to any one of claims 1 to 3 or 5 to 11 , or the composite according to any one of claims 4 or 6 to 10, wherein the aggregating agent is a compound of Formula (II) or a salt thereof:Formula (II), wherein,1006207079X- is an anion; each L is an aryl group or a covalent bond between the oxonium arene and the nitrogen; each R1is independently selected from H and -Cnalkyl; each R2is independently selected from -Cnalkyl, -OCnalkyl and -N(R1)Cnalkyl;R3is -Cnalkyl; in at least one instance n is a number greater than or equal to 6; and wherein the alkyl groups are independently straight-chained or branched.

17. The method according to any one of claims 1 to 3 or 5 to 11 , or the composite according any one of claims 4 or 6 to 10, wherein the aggregating agent is a compound of Formula (la) or a salt thereof;Formula (la) wherein,X- is an anion;R1and R2are independently selected from -Cnalkyl, -OCnalkyl and -N(R3)Cnalkyl;R3is selected from H and -Cnalkyl; in at least one instance n is a number greater than or equal to 6; and wherein the alkyl groups are independently straight-chained or branched.100620707918. The method according to any one of claims 1 to 3 or 5 to 11 , or the composite according to any one of claims 4 or 6 to 10, wherein the aggregating agent is a compound of Formula (Ila) or a salt thereof;Formula (Ila), wherein,X- is an anion; each R1is independently selected from H and -Cnalkyl; each R2is independently selected from -Cnalkyl, -OCnalkyl and -N(R1)Cnalkyl;R3is -Cnalkyl; in at least one instance n is a number greater than or equal to 6; and wherein the alkyl groups are independently straight-chained or branched.

19. The method according to any one of claims 1 to 3 or 5 to 11 , or the composite according to any one of claims 4 or 6 to 10, wherein the aggregating agent is a compound of Formula (lb) or a salt thereof;Formula (lb) wherein,X- is an anion;1006207079R1and R2are independently selected from -Cnalkyl, -OCnalkyl and -N(R3)Cnalkyl;R3is selected from H and -Cnalkyl; in at least one instance of n is a number greater than or equal to 6; and wherein the alkyl groups are independently straight-chained or branched.

20. The method according to any one of claims 1 to 3 or 5 to 11 , the composite according to any one of claims 4 or 6 to 10, wherein the aggregating agent is a compound of Formula (lib) or a salt thereof;Formula (lib), wherein,X- is an anion; each R1is independently selected from H and -Cnalkyl; each R2is independently selected from -Cnalkyl, -OCnalkyl and -N(R1)Cnalkyl;R3is -Cnalkyl; in at least one instance n is a number greater than or equal to 6; and wherein the alkyl groups are independently straight-chained or branched.

21. The method or composite according to any one of claims 15 to 20, wherein in at least one instance n is an integer from 6 to 15, or from 7 to 13.

22. The method or composite according to any one of claims 15 to 21 , wherein X- is selected from halide, hydrogen sulfate, hexafluorophosphate and trifluoroacetate.100620707923. The method or composite according to any one of claims 15, 17, 19, 21 and 22, wherein R1is -N(R3)Cnalkyl.

24. The method or composite according to any one of claims 15 to 23, wherein R2is -N(R3)Cnalkyl.1006207079

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