Method for recovering one or more valuable compounds by flotation

Abstract

The present invention relates to a method for recovering one or more valuable compounds by separating solid particles by flotation, this method comprising the addition of a water-soluble polymer having a specific composition.

Description

[0001] Method for recovering one or more valuable compounds by flotation

[0002] Technical field of the invention

[0003] The present invention relates to a method for separating minerals by flotation, comprising the addition of a water-soluble polymer.

[0004] Prior art

[0005] The industrial growth of the 20th century has required considerable quantities of metals and has pushed mining operators to turn to new sources of raw material, such as metal deposits with a low concentration of ores or release mesh rocks requiring further grinding and for which conventional enrichment methods based on the exploitation of the physical properties (density, magnetic susceptibility, etc.) of minerals are not applicable.

[0006] Mining operators have thus had to develop new techniques for treating these ores, like flotation, which calls upon particular affinities of a physical or chemical nature between a hydrophobising compound and a mineral. The mineral can thus be physically separated using bubbling. Furthermore, the affinity between the hydrophobising compound and the mineral can be modulated in order to create a selective hydrophobisation of certain minerals.

[0007] EP 0 830 208 Bl teaches a method comprising beneficiating value sulfide minerals from ores with selective rejection of non-sulfide silicate gangue minerals. The polymers of EP 0 830 208 Bl are free of any hydrophobic monomer.

[0008] US 4 888 106 teaches a method of using polymeric sulfide mineral depressants.

[0009] US 4 866 150 teaches polymeric sulfide mineral depressants.

[0010] The principle of treating ores by flotation is as follows: an ore is crushed, then ground, generally in a wet process, to reach the release mesh of the valuable compounds and thus form a mineral pulp. The mineral pulp is usually conditioned with pH or redox potential modifiers, as well as different surface modifiers, such as depressants and collectors. These chemical reagents make it possible to modulate the surface physico-chemical properties and thus make it possible to selectively float the particle of interest, whether these are valuable compounds, like a mineral carrying valuable chemical elements or gangue (non-valuable material contained in an ore). The mineral pulp thus conditioned is introduced into a flotation apparatus into which air is injected, in order to generate bubbles which, as they rise, collect the hydrophobised particles of interest. Generally, a foaming agent is also introduced, in order to assist in the formation of small bubbles and to stabilise them to obtain better flotation of the hydrophobised particles of interest. A supernatant foam loaded with hydrophobised particles of interest is thus obtained, which is collected by passive overflow or mechanical scraping. The solid particles, whether they are located in the supernatant foam or whether they have remained in the flotation cell coming at the end of the flotation, then generally undergo one or more solid-liquid separation steps, in particular, thickening and filtration steps.

[0011] Flotation can be adapted to a wide range of compounds. Indeed, according to the choice of collector and of the preconditioning steps with other flotation reagents, it is possible to selectively hydrophobise the surfaces of the material to be floated, which can, in particular, be gangue (reverse flotation) or valuable compounds such as minerals carrying valuable chemical elements such as metals (direct flotation).

[0012] However, the performance of flotation separation depends on numerous parameters (temperature, flotation pH, particle size, mineral proportions, air flow rate, pulp solid rate, choice of flotation reagents, addition sequences and dosages of flotation reagents, etc.). Modifying one of these parameters impacts the other parameters, and it is extremely difficult to study the effects of one single parameter in isolation, and to offer universal treatments.

[0013] In the interest of manufacturers and in the scope of environmental protection, it is necessary to develop new flotation methods, enabling an improvement of the quantity of recovered particles of interest. The Applicant has discovered that the addition, between the addition of the collector and the air bubbling, of a water-soluble polymer having a specific monomer composition, made it possible to improve the quantity of particles of interest recovered during the flotation.

[0014] The method according to the invention is universal and, in particular, makes it possible to improve the recovery of fine or ultra-fine particles, meeting the current constraints of the mining industry, in which ores are ground more and more finely. The method of the invention also enables an improvement in the flotation kinetics of fine and ultra-fine particles.

[0015] Improving the flotation kinetics, enables an increase in the treatment capacity of the flotation equipment already in place, and in the case of new projects, makes it possible to reduce the footprint of the equipment in terms of size, floor space, air consumption and electricity consumption.

[0016] The method according to the invention falls under a principle of environmental awareness and of the impact of industries and man on the planet. The method of the invention makes it possible to reduce the environmental impact of the extraction of valuable compounds coming from the extractive industry (mines and quarries) by reducing the quantity of air and electricity consumed, thus reducing the quantity of greenhouse gases, such as carbon dioxide, released during the extraction of these valuable compounds.

[0017] Furthermore, the present invention is advantageously implemented by means of materials of a biological origin, for example biomass, or recycled. The synthesis of the monomers used is advantageously a biological synthesis, for example, by enzymatic catalysis. The energy used to implement the flotation method according to the invention advantageously comes from a heat pump or from a renewable origin, for example wind power, photovoltaics, or, in particular for mobile installations, of the fuel cell or lithium battery type.

[0018] Disclosure of the invention

[0019] The present invention relates to a method for the flotation of solid particles coming from mines and / or quarries, comprising the addition of a specific water-soluble polymer between the addition of the collector and the air bubbling.

[0020] More specifically, the invention relates to a method for recovering one or more valuable compounds by flotation of solid ore particles, comprising at least the following steps: a) Adding and mixing at least one collector to / with a mineral pulp, in order to form a conditioned pulp PCI, the mineral pulp coming from a mine or a quarry, the mineral pulp comprising water and particles of interest, the particles of interest being solid ore particles; b) Adding and mixing at least one water-soluble polymer to / with the conditioned pulp PCI, in order to form a conditioned pulp PC2, the water-soluble polymer comprising at least:

[0021] - a hydrophobic monomer A, representing between 0.1 and 50 mol% of the monomers of the water-soluble polymer;

[0022] - a hydrophilic monomer B, representing between 50 and 99.9 mol% of the monomers of the water-soluble polymer and chosen from the group consisting of:

[0023] * hydrophilic non-ionic monomers;

[0024] * hydrophilic anionic monomers; and

[0025] * their mixtures; c) Direct or reverse flotation by air bubbling in the conditioned pulp PC2 in order to obtain a charged foam and a treated pulp Pt; d) Recovering the charged foam and putting in an aqueous solution in order to obtain a pulp Pf; e) When step c) is a direct flotation, liquid / solid separation of the pulp Pf in order to obtain a solid SI containing one or more valuable compounds derived from the mineral pulp, or when step c) is a reverse flotation, liquid / solid separation of the treated pulp Pt in order to obtain a solid S2 containing one or more valuable compounds coming from the mineral pulp.

[0026] Description of the invention

[0027] “Solid ore particles” means any solid particles coming from the exploitation of primary mineral resources, but also material particles coming from urban mines, called secondary mineral resources. Consequently, solid particles coming from bituminous sand exploitation are excluded from the scope of the invention.

[0028] “Urban mines” means sites for treating waste electrical and electronic equipment leading to the recovery of material particles, for example the “black mass” obtained during the recycling of lithium-ion batteries or the phosphors of compact fluorescent bulbs.

[0029] “Gangue” means any mineral, crystalline or amorphous species, and non-mineral materials, in particular plastic materials (in the case of waste electrical and electronic equipment) present in an ore, but not valuable.

[0030] “Polymer” means a polymer prepared from at least two different monomers, at least one hydrophobic monomer A and at least one hydrophilic monomer B (chosen from among nonionic hydrophilic monomers and anionic hydrophilic monomers and their mixtures). This polymer can further comprise at least one other monomer chosen from among cationic hydrophilic monomers, zwitterionic hydrophilic monomers and their mixtures.

[0031] The term “hydrophilic monomer” should be understood to mean a monomer that has an octanol-water partition coefficient, log(Kow) less than or equal to 0, in which the partition coefficient Kowis determined at 25°C in an octanol-water mixture with a volume ratio of 1 / 1, at a pH of between 6 and 8.

[0032] The term “hydrophobic monomer” should be understood to mean a monomer that has an octanol-water partition coefficient, log(Kow) greater than 0, in which the partition coefficient Kow is determined at 25°C in an octanol-water mixture with a volume ratio of 1 / 1, at a pH of between 6 and 8.

[0033] The octanol-water partition coefficient, Kow, represents the ratio of concentrations (g / L) of a monomer between the octanol phase and the aqueous phase. It is defined as follows:

[0034] > [monomeroctanolow[monomer]water

[0035] The term "water-soluble polymer" means a polymer r which gives an aqueous solution without insoluble particles when it is dissolved under stirring at 25°C and with a concentration of 10g. L'1in deionised water.

[0036] “X and / or Y” means “X”, or “Y”, or “X and Y”, i.e. the group consisting of X, Y and their mixtures.

[0037] The invention also includes all possible combinations of the various embodiments disclosed, whether they are preferred embodiments or given by way of example. Furthermore, when ranges of values are indicated, the limit values are included in these ranges. The disclosure also includes all of the combinations between the limit values of these ranges of values. For example, the ranges of values “1-20, preferably 5-15”, imply the disclosure of the ranges “1- 20”, “1-5”, “1-15”, “5-20” and “15-20” and of the values 1, 5, 15 and 20.

[0038] Flotation method

[0039] “Particle of interest” means the solid particle that it is desirable to float. In other words, these can be valuable compounds in case of direct flotation, like a mineral contained in an ore, or thus this can be gangue in case of reverse flotation.

[0040] The mineral pulp is advantageously obtained following a comminution of solid particles from mines and / or from quarries. It is generally obtained, but not necessarily, after a crushing step followed by a grinding step, advantageously by a wet process. In the case of urban mines, the grinding step corresponds to the shredding step. These steps aim to reduce the size of the solid particles to reach the release mesh of the valuable compound(s).

[0041] Comminution can be carried out using any type of apparatus known to a person skilled in the art and enabling ore fragmentation. As an example, mention can be made of: a jaw crusher, a cone grinder, a ball grinder or also a (semi-)autogenous grinder.

[0042] The particles of interest are generally obtained after the different comminution steps.

[0043] Thus, the particles of interest of step a) advantageously have a D80 of between 10 and 150 pm, preferably a D80 of between 10 and 63 pm, preferably a D80 of between 10 and 44 pm, more preferably between 10 and 25 pm. Ores with a D80 of less than 10 pm are considered non-treatable by flotation by persons skilled in the art. “D80 of between 10 and 150 pm” means that 80% of the particles of interest have a particle size between 10 pm and 150 pm.

[0044] The term “particle size” means the number-average size of the microparticles. It corresponds to the largest dimension, for example the diameter for spherical particles, measured preferably with a laser measuring device using the conventional techniques which are part of the knowledge of the person skilled in the art. For example, a Malvern Mastersizer, the MS2000, for example, could be used for this purpose. An apparatus of this type can be used to measure, by laser diffraction, the granular distribution of particles in a liquid medium or in solid form, preferably in a multiphase suspension.

[0045] In a preferred embodiment, the particle(s) of interest is a valuable compound. Thus, the particle(s) of interest of step a) are advantageously chosen from the group consisting of: an iron ore, a copper ore, a cobalt ore, a lead ore, a zinc ore, a lithium ore, a phosphate ore, a gold ore, a platinoid ore, a molybdenum ore, a nickel ore, a tin ore, a tungsten ore, an ore of at least one rare earth, a tantalum ore, a niobium ore, a titanium ore, a zirconium ore, a fluorite ore, a barite ore, a potassium ore, polymetallic ores, and their mixtures. Preferably, this is an iron ore, a copper ore, a gold ore, a platinoid ore, the associated polymetallic ores or one of their mixtures. More preferably, this is an iron ore.

[0046] Thus, the valuable compound is advantageously chosen from the group consisting of: iron compounds, copper compounds, cobalt compounds, lead compounds, zinc compounds, lithium compounds, phosphate compounds, gold compounds, platinum compounds, molybdenum compounds, nickel compounds, tin compounds, tungsten compounds, rare earth compounds, tantalum compounds, niobium compounds, titanium compounds, zirconium compounds, fluorite compounds, barite compounds, potassium compounds, polymetallic compounds, and their mixtures. Preferably, this is a compound of iron, copper, gold, platinoids, polymetallic, or a mixture of at least two of these compounds. More preferably, this is an iron compound.

[0047] In a preferred embodiment, the valuable compounds do not come from an urban mine.

[0048] In a preferred embodiment, the valuable compounds are not sulphide mineral particles.

[0049] Step a)

[0050] In step a), at least one collector is added and mixed to / with a mineral pulp.

[0051] The mineral pulp comprises solid particles, advantageously between 20 and 60% by weight with respect to the total weight of the mineral pulp, preferablybetween 30 and 50% by weight.

[0052] During step a), a collector is added.

[0053] The role of the collector is to hydrophobise the particles of interest. The general knowledge of a person skilled in the art enables them to choose the collector, as well as the optional flotation agents (activators, depressants, pH and redox potential modifiers, etc.), according to the nature of the particles of interest.

[0054] The collectors can be classified according to their ionic charge. Generally, the ionic charge is manifested according to the dissociated state of the collector, which can vary according to the pH. The collectors can be non-ionic i.e. non-separable, anionic or cationic.

[0055] In one particular embodiment, the collector is non-ionic.

[0056] Examples of non-ionic collectors are advantageously, and in a non-limiting manner, alcohols (preferably methanol, ethanol or butanol), glycols, polyglycols (advantageously polyethylene glycol or polypropylene glycol), polyols (advantageously glycerol), hydrocarbons (advantageously kerosene), paraffin-rich oils, or naphthene-rich oils.

[0057] In a preferred embodiment, the collector is not non-ionic.

[0058] In one particular embodiment, the collector is anionic. Examples of anionic collectors are, for example and in a non-limiting manner, compounds carrying thiol functions (advantageously xanthates, dithiophosphates, dithiocarbamates, or dithiocarbamates); collectors carrying carboxylic, sulfonic, phosphonic, sulfosuccinate, or sulfosuccinamate functions and their salts; or fatty acids, advantageously Cs to C30.

[0059] In a preferred embodiment, the collector is cationic.

[0060] Examples of cationic collectors are, for example and in a non-limiting manner, compounds carrying ammonium functions (-NR.3 , with R being able to independently represent a hydrogen atom or a Ci-Ce hydrocarbon chain), amine ethers, mercaptobenaothiazole salts, or cationic dithiophosphates.

[0061] The quantity of collector added to the pulp, during step a), is advantageously between 10 and 500 g / t with respect to the total quantity of solid particles in the mineral pulp, preferably between 10 and 100 g / t, more preferably between 20 and 50 g / t by weight.

[0062] Once the collector has been added and mixed, a conditioned pulp PCI is obtained.

[0063] In one particular embodiment, the method of the invention comprises the addition of at least one depressant and / or at least one activator before the addition of the collector.

[0064] These products are used to modify the mineral surfaces and affect the affinity between the collector and certain mineral surfaces improving the selectivity of the collector with respect to the particles of interest.

[0065] As a depressant, mention can be made, as an example, of sodium silicate for silicates; starch and its derivatives for iron oxides; lime for pyrite; sodium cyanide or zinc sulphate for sphalerite; and hydrofluoric acid for feldspars. By extension, pH regulators can also be considered as depressants.

[0066] As an activator, mention can be made, as an example, of copper sulphate to reactivate the previously depressed surface of sphalerite; sodium hydrogen sulphide for copper oxides; and soluble metal salts. By extension, pH regulators can also be considered as activators in certain cases.

[0067] All of these compounds are known to a person skilled in the art, and they will know how to select them according to the type of particles of interest that they wish to float. A person skilled in the art will know how to adjust the quantity of depressant and / or activator according to the ore.

[0068] Step b)

[0069] In step b), at least one water-soluble polymer is added and mixed to / with the conditioned pulp PCI. This addition makes it possible to form the conditioned pulp PC2.

[0070] The addition of the water-soluble polymer can be done once or several times (advantageously separated by a mixing step). Preferably, the addition is done once.

[0071] The water-soluble polymer comprises at least:

[0072] - a hydrophobic monomer A representing between 0.1 and 50 mol% of the water-soluble polymer;

[0073] - a hydrophilic monomer B, representing between 50 and 99.9 mol% of the monomers of the water-soluble polymer and chosen from the group consisting of:

[0074] * hydrophilic non-ionic monomers;

[0075] * hydrophilic anionic monomers; and

[0076] * their mixtures.

[0077] The hydrophobic monomer A may comprise one or more halogen atoms, for example chlorine.

[0078] The hydrophobic monomer A of the water-soluble polymer added during step b) is advantageously chosen from the group consisting of: (meth)acrylic acid esters having a chain of (i) C4-C30 alkyl, or (ii) arylalkyl having a C4-C30 alkyl and a C4-C30 aryl, or (iii) propoxylated, or (iv) ethoxylated, or (v) ethoxylated and propoxylated; alkyl aryl sulfonates having a C4-C30 alkyl and a C4-C30 aryl; mono-substituted amides of (meth)acrylamide having a chain (i) C4-C30 alkyl, or (ii) arylalkyl having a C4-C30 alkyl and a C4-C30 aryl, or (iii) propoxylated, or (iv) ethoxylated, or (v) ethoxylated and propoxylated; di -substituted amides of (meth)acrylamide having two chains chosen from among (i) C4-C30 alkyl, or (ii) arylalkyl having a C4-C30 alkyl and a C4-C30 aryl, or (iii) propoxylated, or (iv) ethoxylated, or (v) ethoxylated and propoxylated; anionic or cationic monomer derivatives of (meth)acrylamide carrying a hydrophobic chain; anionic or cationic monomer derivatives of (meth)acrylic acid carrying a hydrophobic chain; vinylpyridine; and their mixtures. Among these hydrophobic monomers A:

[0079] - the alkyl groups are preferably C4-C20, more preferably C4-C8. C6-C20 alkyls are preferably linear alkyls, while C4-C5 are preferably branched,

[0080] - the arylalkyl groups are preferably C7-C25, more preferably C7-C15,

[0081] - ethoxyl chains advantageously comprise between 1 and 200 -CH2-CH2-O- groups, preferably between 6 and 100, more preferably between 10 and 40,

[0082] - propoxyl chains advantageously comprise between 1 and 50 -CH2-CH2-CH2-O- groups, more preferably between 1 and 20.

[0083] Preferred hydrophobic monomers A belonging to these classes are, advantageously:

[0084] - n-hexyl (meth)acrylate, n-octyl (meth)acrylate, octyl (meth)acrylamide, lauryl (meth)acrylate, lauryl (meth)acrylamide, myristyl (meth)acrylate, myristyl (meth)acrylamide, pentadecyl (meth)acrylate, pentadecyl (meth)acrylamide, cetyl (meth)acrylate, cetyl (meth)acrylamide, oleyl (meth)acrylate, oleyl (meth)acrylamide, erucyl (meth)acrylate, erucyl (meth)acrylamide, N-tert-Butyl(meth)acrylamide, vinylpyridine, 2-ethylhexyl acrylate, C4-C22 itaconic acid hemi-esters, acidified or quaternised C4-C22(meth)arcrylate dialkyl aminoalkyl salts, acidified or quaternised C4-C22 dialkyl-aminoalkyl(meth)acrylamide salts, undecanoic acrylamido acid, and their mixtures,

[0085] - cationic allyl derivatives having a formula (I) or (II): wherein:

[0086] R: independently, a hydrogen atom, an alkyl chain containing 1 to 4 carbons;

[0087] Ri: an alkyl or arylalkyl chain comprising 8 to 30 carbons;

[0088] X: a halide chosen from the group composed of bromides, chlorides, iodides, fluorides and of any negatively charged counter-ion; and

[0089] - preferably, cationic derivatives of the (meth)acryloyl type responding to formula (III):

[0090] f tTTT) wherein:

[0091] * A represents O or N-R5 (preferably A represents N-R5),

[0092] * R2, R3, R4, Rs, Re, R7: independently, a hydrogen atom or an alkyl chain containing 1 to 4 carbons,

[0093] * Q: an alkyl chain comprising 1 to 20 carbons,

[0094] * Rs: an alkyl or arylalkyl chain comprising 8 to 30 carbons,

[0095] * X: a halide chosen from the group composed of bromides, chlorides, iodides, fluorides, and any negatively charged counter-ion.

[0096] A particularly preferred hydrophobic monomer A is 2-ethylhexyl acrylate (EHA); dodecyl vinyl ether (DVE); butyl acrylate (BA) or 1-dodecanaminium, N,N-dimethyl-N-[3-[(2- methyl-l-oxo-2-propen-l-yl)amino]propyl]-, bromide (BAM25), more preferably BAM25 (CH2=CH(CH3)-C(=O)-NH-(CH2)3)-N(CH3)2-(CH2)ii-CH3.Br).

[0097] The quantity of hydrophobic monomers A represents between 0.1 and 50 mol% of the water- soluble polymer monomers, preferably between 1 and 45 mol%, more preferably between 2 and 40 mol%, more preferably between 3 and 30 mol%, more preferably between 5 and 25 mol%, more preferably between 10 and 20 mol%.

[0098] A person skilled in the art will know how to adjust the quantity of hydrophobic monomers A according to the hydrophobicity of the latter and optionally of the quantity of hydrophilic monomers C (the monomers C being cationic and / or zwitterionic as specified below), such that the water-soluble polymer remains soluble in water. Eventually, one or more transfer agents may be used. Advantageously, the non-ionic hydrophilic monomers B of the water-soluble polymer added during step b) are chosen from the group consisting of: acrylamide, methacrylamide, N- alkylacrylamides, N-alkylmethacrylamides, N,N-dialkyl acrylamides (for example, N,N- dimethylacrylamide or N,N-di ethyl acrylamide), N,N-dialkylmethacrylamides, acrylic acid alkoxyl esters, methacrylic acid alkoxyl esters, N-vinylpyrrolidone, N- methylol(meth)acrylamide, N-vinyl caprolactame, N-vinylformamide (NVF), N-vinyl acetamide, N-vinyl imidazole, N-vinyl succinimide, acryloyl morpholine (ACMO), acryloyl chloride, glycidyl methacrylate, vinyl acetate, glyceryl methacrylate, diacetone acrylamide, methacrylic anyhydride, acrylonitrile, maleic anydride, itaconic anhydride, itaconamide, hydroxyalkyl (meth)acrylate, thioalkyl (meth)acrylate, alcoxyl derivatives of isoprenol, hydroxy ethyl(meth)acrylates; alcoxyl derivatives of hydroxy ethyl(meth)acrylates, hydroxypropyl(meth)acrylate, alcoxyl derivatives of hydroxypropyl(meth)acrylate, and their mixtures. From among these non-ionic monomers, the alkyl groups are advantageously C1-C5, more advantageously C1-C3. Advantageously, the C3-C5 alkyl groups are advantageously branched. Preferably, the hydrophilic non-ionic monomer B is acrylamide or N- vinylpyrrolidone, more preferably acrylamide.

[0099] Advantageously, the anionic hydrophilic monomer(s) B used in the scope of the invention can be chosen from a wide group. These monomers may have a vinyl function, in particular, acrylic, maleic, fumaric, malonic, itaconic, or allylic. They can also contain a carboxylate, phosphonate, phosphate, sulfonate, sulfate group, or another anionic filler group. Advantageously, the anionic hydrophilic monomer(s) B used in the scope of the invention are chosen from among: acrylic acid; methacrylic acid; dimethylacrylic acid; acryloyl chloride; crotonic acid; maleic acid; fumaric acid; 3-acrylamido 3 -methylbutanoic acid; strong acidtype monomers having, for example, a sulfonic acid- or phosphonic acid-type function, such as vinylsulfonic acid, vinylphosphonic acid, allylsulfonic acid, methallylsulfonic acid, 2- methylidenepropane-l,3-disulfonic acid, 2-sulfoethylmethacrylate, sulfopropylmethacrylate, sulfopropylacrylate, allylphosphonic acid, ethylene glycol methacrylate phosphate, sulfonic styrene acid, 2-acrylamido-2-methylpropane sulfonic acid (ATBS), 2-acrylamido-2- methylpropane disulfonic acid, 3-allyloxy-2-hydroxypropane sulfonic acid, diethylallylphosphonate, carboxyethyl acrylate; water-soluble salts of these monomers as their alkaline metal salts, alkaline earth metals, or ammonium; and their mixtures. Preferably, the hydrophilic anionic monomer B is acrylic acid, maleic acid or 2-acrylamido-2- methylpropanesulphonic acid (ATBS), more preferably acrylic acid or ATBS. In one particular embodiment, when the anionic hydrophilic monomer is 2-acrylamido-2- methylpropanesulphonic acid (ATBS), it is its hydrated form. The hydrated form of ATBS is a particular form of ATBS, obtained by controlled crystallisation of the ATBS monomer. The document U.S. Pat. No. 10,759,746 describes this hydrated form of the ATBS.

[0100] In one particular embodiment of the invention, the hydrophilic anionic monomer(s) B may be salified. This may also be a mixture of acid form and salified form, for example, a mixture of acrylic acid and acrylate. By salified, this means the substitution of a proton of at least one acid function of the - Ra(=O)-OH type (with Rarepresenting P, S or C) of the anionic monomer by a metal cation or organic cation to form a salt of the -Ra(=O)-O A+type (A+being a metal cation or an organic cation). In other words, the non-salified form corresponds to the acid form of the monomer, for example Rb-C(=O)-OH in the case of the carboxylic acid function, while the salified form of the monomer corresponds to the Rb-C(=O)-O' A+form, A+being a metal cation or an organic cation. The salification of the acid functions can be partial or total.

[0101] The metal cation is advantageously an alkaline metal ion (Li+, Na+, K+, etc.) or an alkaline earth metal (Ca2+, Mg2+, etc.), and the organic cation is advantageously ammonium ion or a tertiary ammonium. The preferred salts are sodium salt.

[0102] The salification may take place before or after polymerisation.

[0103] The quantity of hydrophilic monomers B represents between 50 and 99.9 mol% of the water- soluble polymer monomers, preferably between 55 and 99 mol%, more preferably between 60 and 98 mol%, more preferably between 70 and 97 mol%, more preferably between 75 and 95 mol%, and even more preferably between 80 and 90 mol%.

[0104] In a preferred embodiment, the hydrophilic monomer B is a non-ionic hydrophilic monomer.

[0105] The water-soluble polymer can further comprise at least one hydrophilic monomer C chosen from among: anionic hydrophilic monomers, cationic hydrophilic monomers, zwitterionic hydrophilic monomers and their mixtures.

[0106] In a preferred embodiment, the hydrophilic monomer C is at least one cationic hydrophilic monomer. The cationic hydrophilic monomer(s) C used in the scope of the invention are chosen, in particular, from among vinyl-type monomers, in particular acrylamide, acrylic, allylic or maleic having a protonable amine or ammonium, advantageously quaternary ammonium function. Advantageously, the cationic hydrophilic monomer(s) C used in the scope of the invention are chosen from among: diallyldialkyl ammonium salts like dimethyldiallylammonium chloride (DADMAC); acidified or quatemised dialkyl- aminoalkyl(meth)acrylamide salts, like for example (3- methacrylamidopropyl)trimethylammonium chloride (MAPTAC), (3- acrylamidopropyl)trimethylammonium chloride (APTAC); acidified or quaternised dialkylaminoalkyl acrylate salts like quatemised or salified dimethylaminoethyl acrylate (DMAEA); acidified or quaternised dialkyl aminoalkyl methacrylate salts like quaternised or salified dimethylaminoethyl methacrylate (DMAEMA); acidified or quaternised N,N- dimethylallylamine salts; acidified or quatemised diallylmethylamine salts; acidified or quaternised diallylamine salts; vinylamine obtained by hydrolysis (basic or acid) of an amide group -N(R2)-CO-R1with R1and R2being, independently, a hydrogen atom or an alkyl chain of 1 to 6 carbons, for example vinylamine coming from the hydrolysis of vinylformamide; vinylamine obtained by Hofmann degradation; and their mixtures. Advantageously, the alkyl groups are C1-C7, preferably C1-C3 and can be linear, cyclic, saturated or unsaturated chains. Preferably, the cationic hydrophilic monomer C is chosen from among the acidified or quaternised salts of dimethylaminoethyl (meth)acrylate, (3- (meth)acrylamidopropyl)trimethylammonium chloride, and their mixtures.

[0107] A particularly preferred cationic hydrophilic monomer C is benzyl dimethylaminoethyl acrylate chloride, dimethylaminoethyl acrylate methylchloride or DADMAC.

[0108] A person skilled in the art will know how to prepare the quaternised monomers, for example, by means of an R-X-type quatemisation agent, R being an alkyl group and X being a halogen or a sulphate.

[0109] The term “quatemisation agent” means a molecule being able to alkylate a tertiary amine.

[0110] The quatemisation agent may be selected from among dialkyl sulphates comprising 1 to 6 carbon atoms or alkyl halides comprising 1 to 6 carbon atoms. Preferably, the quatemisation agent is selected from among methyl chloride, benzyl chloride, dimethyl sulphate or diethyl sulphate. Furthermore, the present invention also covers DADMAC, APTAC and MAPTAC monomers in which the counterion is sulphate, fluoride, bromide or iodide instead of chloride.

[0111] The zwitterionic hydrophilic monomer(s) used in the scope of the invention are chosen, in particular, from among the derivatives of a vinyl-type pattern (advantageously acrylamide, acrylic, allylic or maleic), this monomer has a quaternary amine or ammonium function and a carboxylic- (or carboxylate)-, sulfonic- (or sulfonate)- or phosphoric- (or phosphate)-type acid function.

[0112] Preferably, this monomer includes a quaternary amine or ammonium function and a carboxylic-type acid function (or carboxylate), sulfonic (or sulfonate) or phosphoric (or phosphate).

[0113] Advantageously, the zwitterionic hydrophilic monomers used in the scope of the invention are chosen from among: acrylate dimethylaminoethyl derivatives, such as 2-((2-9(acryloyloxy) ethyl)dimethylammonio) ethane- 1 -sulfonate, can be mentioned in particular, and in a nonlimiting manner, 3-((2-(acryloyloxy)ethyl) dimethylammonio) propane- 1 -sulfonate, 4-((2- (acryloyloxy)ethyl) dimethylammonio) butane- 1 -sulfonate, [2- (acryloyloxy)ethyl](dimethylammonio)acetate, methacrylate dimethylaminoethyl derivatives, such as 2-((2-(methacryloyloxy) ethyl)dimethylammonio)ethane-l -sulfonate, 3-((2- (methacryloyloxy)ethyl) dimethylammonio)propane-l -sulfonate, 4-((2- (methacryloyloxy)ethyl) dimethylammonio)butane-l -sulfonate, [2- (methacryloyloxy)ethyl](dimethylammonio) acetate, propyl acrylamide dimethylamino derivatives, such as 2-((3-acrylamidopropyl) dimethylammonio)ethane-l -sulfonate, 3-((3- acrylamidopropyl)dimethylammonio) propane- 1 -sulfonate, 4-((3- acrylamidopropyl)dimethylammonio)butane-l -sulfonate, [3- (acryloyl)oxy)propyl](dimethylammonio)acetate, dimethylamino propyl methylacrylamide, or also derivatives, such as 2-((3-methacrylamidopropyl)dimethylammonio)ethane-l -sulfonate, 3 -(dimethylammonio)propane-l -sulfonate 4-((3- methacrylamidopropyl)dimethylammonio)butane-l -sulfonate and propyl [3- (methacryloyloxy)](dimethylammonio)acetate and their mixtures.

[0114] Other zwitterionic monomers are described by the Applicant in document WO2021 / 123599 Al. The quantity of hydrophilic monomers C (cationic and / or zwitterionic) represents between 0 and 49.9 mol% of the monomers (A+B+C) of the water-soluble polymer, preferably between 0.1 and 25 mol%, preferably between 0.1 and 15 mol%, more preferably between 0.1 and 5 mol%.

[0115] The quantities of the different monomers A, B and optionally C will be adjusted by a person skilled in the art in order to reach 100 mol% of the water-soluble polymer.

[0116] The water-soluble polymer can have a linear, branched, cross-linked, star-shaped or combshaped structure. Preferably, it is linear. This structure can be obtained, according to the general knowledge of a person skilled in the art, for example by selecting the initiator, the transfer agent, the polymerisation technique such as Reversible Addition Fragmentation chain Transfer Polymerisation (RAFT), Nitroxide Mediated Polymerisation (NMP) or Atom Transfer Radical Polymerisation (ATRP), the incorporation of structural monomers, or the concentration.

[0117] The water-soluble polymer may be structured by a branching agent. By structured polymer, this means a non-linear polymer, which has side chains.

[0118] The branching agent is advantageously chosen from:

[0119] - structural agents, being able to be selected from the group comprising unsaturated polyethylene compounds (having, as a mininum, two unsaturated functions, except for compounds of the diallyldialkyl ammonium type), like for example, vinyl functions, in particular allyl or acrylic, and for example, methylene bis acrylamide (MBA), triallyamine, or tetraallylammonium chloride or 1,2 dihydroxy ethylene bis-(N-acrylamide) can be mentioned,

[0120] - compounds having at least two epoxy functions,

[0121] - compounds having at least one unsaturated function and one epoxy function,

[0122] - macroinitiators such as polyperoxides, polyazoics and transfer polyagents, such as polymercaptan polymers, and polyols,

[0123] - functionalised polysaccharides,

[0124] - water-soluble metal complexes composed:

[0125] * of a metal of a valence greater than 3 such as, by way of example and in a non-limiting manner, aluminium, boron, zirconium, or also titanium, and

[0126] * of a ligand carrying a hydroxyl function. When the water-soluble polymer comprises at least one branching agent, it remains soluble in water. A person skilled in the art knows how to adjust the quantity of branching agent and, possibly, the quantity of transfer agent needed to obtain this result.

[0127] In one particular embodiment, the water-soluble polymer may comprise a transfer agent.

[0128] The transfer agent is advantageously chosen from among methanol; isopropylic alcohol; sodium hypophosphite; calcium hypophosphite; magnesium hypophosphite; potassium hypophosphite; ammonium hypophosphite; formic acid; sodium formiate; calcium formiate; magnesium formiate; potassium formiate; ammonium formiate; 2-mercaptoethanol; 3- mercaptopropanol; glycol dithiopropylene; thioglycerol; thioglycolic acid; thiohydracrylic acid; thiolactic acid; thiomalic acid; cysteine; aminoethanethiol; thioglycolates; allyl phosphites; allyl mercaptans; sodium methallysulphonate; calcium methally sulphonate; magnesium methallysulphonate; potassium methallysulphonate; ammonium methallysulphonate; polythiols, and their mixtures. Preferably, this is sodium hypophosphite or sodium formiate.

[0129] The quantity of transfer agent in the water-soluble polymer is advantageously between 10 and 20,000 ppm with respect to the total weight of the monomers (A, B and optionally C) of the polymer, preferably between 100 and 10,000 ppm, more preferably between 500 and 5,000 ppm.

[0130] The water-soluble polymer advantageously has a weight molecular weight of at least 0.5 million g / mol, preferably between 0.5 and 20 million g / mol, more preferably between 0.8 and 10 million g / mol, more preferably between 1 and 5 million g / mol.

[0131] The average molecular weight by weight is preferably measured by gel permeation chromatography coupled with a Malls detector.

[0132] The water-soluble polymer is preferably selected from the group consisting of:

[0133] - polymers of acrylamide, acrylic acid and 2-ethylhexyl acrylate,

[0134] - polymers of acrylamide, ATBS and 2-ethylhexyl acrylate,

[0135] - polymers of acrylamide and 2-ethylhexyl acrylate,

[0136] - polymers of maleic acid and butyl acrylate,

[0137] - polymers of acrylamide, ADC and 2-ethylhexyl acrylate, - polymers of acrylamide and 1-dodecanaminium, N,N-dimethyl-N-[3-[(2-methyl-l-oxo-2- propen-l-yl)amino]propyl]-, bromide (BAM25).

[0138] Generally, the water-soluble polymer can be obtained according to any polymerisation techniques well-known by a person skilled in the art. These include solution polymerization; gel polymerization; precipitation polymerization; emulsion polymerization (aqueous or inverse); suspension polymerization; reactive extrusion polymerization; water-in-water polymerization; or micellar polymerization. Preferably, this is solution or powder polymerisation.

[0139] The polymerisation is generally free radical polymerisation. By free radical polymerisation, free radical polymerisation by means of UV, azoic, redox or thermal primers are included, as well as controlled radical polymerisation (CRP) techniques or on-matrix polymerisation techniques.

[0140] The quantity of primer is advantageously between 100 and 10,000 ppm with respect to the weight of all of the monomers (A, B and optionally C) of the water-soluble polymer, preferably between 500 and 5,000 ppm.

[0141] The quantity of water-soluble polymer added to the conditioned pulp PCI is advantageously between 1 and 1,000 g / t (grams per metric tonne of solid particles contained in the conditioned pulp PCI), preferably between 1 and 500 g / t by weight, more preferably between 1 and 100 g / t by weight.

[0142] In a particular embodiment, the hydrophilic monomer B is non-ionic and the water-soluble polymer comprises between 0.1 and 25 mol% of cationic monomer, preferably between 0.1 and 15 mol% of cationic monomer, more preferably between 0.1 and 5 mol% of cationic monomer.

[0143] The cationic monomer can be chosen from among all the monomers described above, this can be hydrophobic monomer(s) A or hydrophilic monomer(s) C. Preferably, these are monomer(s) chosen from among the monomers A.

[0144] Once the water-soluble polymer is added and mixed, a conditioned pulp PC2 is obtained.

[0145] The addition of the polymer is advantageously preceded or followed by the addition of a foaming agent. The foaming agent can be chosen from among aliphatic alcohols, cyclic alcohols (in particular, pine oil), aromatic alcohols (in particular, cresols), polyglycols, and their mixtures.

[0146] The quantity of foaming agent added to the conditioned pulp (PCI or PC2 according to the order of addition) is advantageously between 0 and 1,000 g / t with respect to the total weight of solid particles contained in the conditioned pulp (PCI or PC2 according to the order of addition), preferably between 1 and 500 g / t, more preferably between 2 and 100 g / t and even more preferably between 5 and 50 g / t.

[0147] Step c)

[0148] The bubbling of the conditioned pulp PC2 is advantageously carried out in a flotation cell. The flotation cell can be mechanical (for example, like Wemco-type cells), or it can be pneumatic (for example, like flotation columns and intensive flotation cells, in particular of the Jameson or Imhoflot™ or Concorde Cell™ type). Preferably, these are mechanical flotation cells.

[0149] “Flotation cell” means both mechanical and pneumatic cells, the two terms being interchangeable.

[0150] The gas used can be air, oxygen, hydrogen, nitrogen, carbon dioxide, or a mixture of several of these gases. Preferably, this is air.

[0151] The bubbling of the conditioned pulp PC2 makes it possible to cause the flocs of hydrophobised particles of interest (thanks to the addition of the polymer during step a)) to rise to the top of the flotation cell in order to accumulate them within a charged foam which is then recovered during step d).

[0152] Advantageously, the flotation of step c) is a direct flotation.

[0153] Step d)

[0154] The charged foam is recovered, for example by overflowing or mechanical scraping, and returned into aqueous solution, in order to obtain a pulp Pf.

[0155] Whatever the type of flotation, the pulp Pf is enriched in particles of interest, while the pulp Pt is depleted in particles of interest, the term particles of interest meaning the solid particles that it is desirable to float, whether they are valuable compounds or gangue. According to the type of flotation, the pulp Pf comprises a majority of at least one particle of interest, whether it is a valuable compound and / or gangue. Likewise, according to the type of flotation, the treated pulp Pt can comprise a majority of another valuable compound and / or gangue.

[0156] In the case of direct flotation, the pulp Pf advantageously comprises at least 50% by weight of particles of interest with respect to the total weight of the particles present in the pulp Pf, while the pulp Pt advantageously comprises at least 50% by weight of gangue and optionally other valuable compounds with respect to the total weight of the particles present in the pulp Pt.

[0157] In the case of reverse flotation, the pulp Pf advantageously comprises at least 50% by weight of gangue and optionally other valuable compounds with respect to the total weight of the particles present in the pulp Pf, while the pulp Pt advantageously comprises at least 50% by weight of particles of interest with respect to the total weight of the particles present in the pulp Pt.

[0158] Step e)

[0159] If step c) is a direct flotation, step e) consists of a solid-liquid separation of the pulp Pf in order to obtain a solid SI containing one or more valuable compounds coming from the mineral pulp.

[0160] If step c) is a reverse flotation, a solid-liquid separation of the treated pulp Pt is carried out in order to obtain a solid S2 containing one or more valuable compounds coming from the mineral pulp.

[0161] The solid-liquid separation can be carried out by any means known to a person skilled in the art. As an example, mention can be made of separation by decantation, by filtration, or by centrifugation. The solid-liquid separation is preferably carried out by decantation, then filtration.

[0162] The solid-liquid separation by decantation can be carried out by any type of decanters known to a person skilled in the art. As an example, mention can be made of conventional-type decanters, high-flow-type decanters, high-density -type decanters and pulp-type decanters. Preferably, this is decantation by conventional-type decanters or a high flow-type decanter. The solid-liquid separation by filtration can be carried out by any type of equipment known to a person skilled in the art. As an example, mention can be made of filtration by filter press, by band filter, by disc filter. Preferably, this is filtration by filter press or by disc filter.

[0163] The method according to the invention can further comprise n (n being an integer of between 1 and 5) consecutive sequences of steps a) to d), before step e), in order to recover all the valuable compounds from the mineral pulp.

[0164] In a particular embodiment, it is possible to use SI or S2 to form a mineral pulp which can be used in a second flotation method according to the method of the invention. The SI’ and S2’ resulting from this second flotation method can in turn be used in a third flotation method according to the method of the invention and so on, until all of the particles of interest have been extracted from the solid ore particles.

[0165] The polymer of the invention can further be used, in order to improve the performance of other wet mineral processing techniques, i.e. mineral separation, and particularly the magnetic separation of fine ores. In these techniques, using the water-soluble polymer can also be done in combination with depressants, activators and optional collectors.

[0166] The water-soluble polymer implemented in the invention is advantageously of biological or recycled origin. Advantageously, it has a biosourced carbon content of between 5% by weight and 100% by weight with respect to the total weight of carbon in the water-soluble polymer, the biosourced carbon content being measured according to standard ASTM D6866-21, method B.

[0167] The energy used to implement the flotation method according to the invention advantageously comes from a heat pump or from renewable origin, advantageously of the wind, photovoltaic, fuel cell or lithium battery type.

[0168] The invention and its advantages will be better understood in the light of the following figures and examples provided in order to illustrate the invention in a non-limiting manner.

[0169] Examples

[0170] List of abbreviations:

[0171] SIBX: Sodium isobutyl xanthate

[0172] AM: Acrylamide AA: Acrylic acid

[0173] EHA: 2-ethylhexyl acrylate

[0174] NVP: N-vinylpyrrolidone

[0175] ADC: Dimethylaminoethyl acrylate methyl chloride

[0176] DADMAC: Diallyldimethylammonium chloride

[0177] MAA: Maleic acid

[0178] ATBS: 2-acrylamido-2-methylpropane sulfonic acid

[0179] BAM25: 1-dodecanaminium, N,N-dimethyl-N-[3-[(2-methyl-l-oxo-2-propen-l- yl)amino]propyl]-, bromide

[0180] DVE: Dodecyl vinyl ether

[0181] BA: Butyl acrylate

[0182] Determining the molecular weight by GPC-Malls

[0183] Permeable gel chromatography (GPC) makes it possible to separate macromolecules according to their hydrodynamic volume. It is coupled to a Malls detector, making it possible to measure the diffusion of light at several angles.

[0184] The synthesised polymers are analysed under the following conditions:

[0185] - Instrument: Agilent 1260 Infinity system and Wyatt Technology detectors from Wyatt Technology.

[0186] Columns:

[0187] Shodex™ SB-807-G

[0188] Shodex™ SB-806-HQ

[0189] Shodex™ SB-805 custom

[0190] Shodex™ SB-803 -HQ

[0191] Shodex™ SB-802-HQ- Method:

[0192] * Temperature: 25°C

[0193] * Mobile phase: 0.4 M NaNCh, 100 ppm NaNs + TFA (pH 3.5) (TFA = trifluoroacetic acid)

[0194] * Injection: 100 pL

[0195] * Flow rate: 0.5 mL / min

[0196] * Analysis time: 110 min

[0197] Model: Zimm order 1

[0198] GCP 3

[0199] * Detection: (i) Dawn Heleos: Light scattering detector (MALS)

[0200] (ii) Optilab T-Rex:Refractometry (RI)

[0201] Metal content determination

[0202] In all the examples, the content of metal recovered by the flotation, direct or reverse, was measured by ICP-OES (Inductively Coupled Plasma Optical Emission Spectrometry) dosage: Solid samples from the concentrate and tailings were digested using a mixture of nitric acid and hydrochloric acid (3 : 1 v / v) at approximately 90 °C for 2 hours.

[0203] The resulting solutions were diluted with deionized water and filtered prior to analysis. Measurements were performed using a Agilent 5110 ICP-OES, calibrated with certified multi-element standard solutions.

[0204] The wavelength selected in ICP-OES depends on each element’s emission spectrum. It is chosen based on sensitivity, potential spectral interferences, and expected concentration range.

[0205] Element-specific wavelengths were selected as follows: Cu at 324.75 nm, Fe at 238.20 nm, Zn at 213.86 nm, Si at 251.61 nm, Mg at 285.21 nm, Ca at 317.93 nm, P at 213.62 nm, and Au at 267.59 nm, Pt at 265.94 nm, Pd at 340.46 nm and Rh at 343.49 nm. The recovery percentage of a given metal was calculated using the formula:

[0206] Cconc * mconc

[0207] Recovery (%) = 100 *

[0208] Ctotal * mtotal wherein: C is the concentration of the metal (mg / L) measured by ICP-OES and m is the mass of the corresponding solid phase (concentrate or feed).

[0209] Each measurement was carried out in triplicate, and the average value was used for data reporting.

[0210] Determining viscosity

[0211] Viscosity is measured using a Brookfield viscometer at 25°C with a Brookfield module LV4 speed 30 rpm, 1 M NaCl. Example 1 - Direct flotation of zinc ores

[0212] Flotation tests were carried out using a Denver laboratory flotation cell equipped with a 2.5 L vessel, operating with 2.0 L of aqueous mineral pulp.

[0213] The mineral pulp used for the tests was sampled from a zinc flotation processing plant. This pulp had an initial zinc content of 7.5 wt%.

[0214] The zinc is primarily hosted in sphalerite. The pH of the pulp was adjusted to 11 using lime milk.

[0215] After an 8 minute mixing period, SIBX (collector) was added at a dosage of 40 g / t of solids contained in the mineral pulp, forming the conditioned pulp PCI (step a).

[0216] Following a 2 minute mixing period, a solution of polymer P1-P4, prepared at 10 g / L in water, was added to the flotation cell at a dosage of 5 g / t of solids to form the conditioned pulp PC2 (step b).

[0217] After an additional 1 minute mixing period, a water-soluble polyglycol-based frother was added at a dosage of 10 g / t of solids.

[0218] Following another 1 minute mixing period, air was introduced into the flotation cell (aeration of the conditioned pulp PC2; to initiate direct flotation, resulting in a loaded froth and a treated pulp Pt step c).

[0219] The total flotation time for zinc was 12 minutes.

[0220] The loaded froth was recovered and redispersed in water to form a pulp Pf (step d).

[0221] A solid / liquid separation of pulp Pf was performed to obtain solid SI (step e).

[0222] A similar separation of the treated pulp Pt yielded solid S2.

[0223] The particle size distribution of solid SI showed a D80 of 32 pm.

[0224] Four polymers (P1-P4) were tested; their compositions are detailed in Table 1.

[0225] Table 1 - Composition and features of P1-P4 polymers

[0226] Table 2 - Results of flotation tests 1-1 to 1-5

[0227] The results obtained (Table 2) show that the polymers according to the invention (P2 and P4) overall improve zinc recovery (a recoverable component), with better selectivity (Zn content in SI) and a higher recovery rate (percentage of Zn recovered in SI relative to the initial amount of Zn in the mineral pulp).

[0228] Example 2 - Order addition

[0229] The same protocol as in test 1-3 was followed, except for the order in which the flotation reagents were added.

[0230] The different addition sequences and the corresponding results are summarized in Table 3.

[0231] Counter example, Inv: Invention)

[0232] The results show that the addition sequence according to the invention is essential for optimizing the flotation process, both in terms of the proportion of ore recovered in solid SI and the recovery yield relative to the amount of ore in the mineral pulp.

[0233] Example 3 - Reverse flotation of iron ores

[0234] Flotation tests were carried out using a laboratory Agitair flotation cell equipped with a 1.5 L vessel.

[0235] The mineral pulp used was sampled from an industrial iron ore flotation plant and had an initial iron (Fe) content of 39 wt% and a silicate gangue minerals (SiGM) content of 21 wt%. The mineral pulp was first dried at 80°C for 48 hours and divided into 1100 g samples.

[0236] The iron is primarily hosted in chalcopyrite, bornite, and pyrite.

[0237] Each sample was resuspended in 920 mL of tap water.

[0238] After 5 minutes of mixing under agitation at 900 rpm, 800g / t of a starch depressant preactivated with caustic soda (starch / NaOH ratio 7: 1) was introduced.

[0239] The pH was then adjusted to 9.5.

[0240] 160 g / t of a collector Clariant EDC 7072 was added in the form of a 1 wt% aqueous solution, at the desired dosage to form a conditioned pulp PCI (step a).

[0241] Following a further 2 minute mixing period at 900 rpm, a solution of water-soluble polymer at a concentration of 10 g / L was added to the flotation cell at the desired dosage to form a conditioned pulp PCI (step b).

[0242] After an additional 1 minute mixing period at 900 rpm, the agitation speed was reduced to 800 rpm and air was introduced into the flotation cell (step c), initiating the reverse flotation of silicates and resulting in the formation of a loaded froth and a treated pulp Pt. The total flotation time was 5 minutes.

[0243] The loaded froth was recovered and redispersed in water to form a pulp Pf (step d).

[0244] A solid / liquid separation was performed on the pulp Pf to obtain solid SI (step e).

[0245] A similar separation of the treated pulp Pt yielded a solid S2.

[0246] The particle size distribution of solid SI exhibited a D80 of 80 pm. Eight water-soluble polymers (P5-P13) were tested. Their compositions are summarized in

[0247] Table 4.

[0248] Table 4 - P5-P13 compositions

[0249] Flotation results

[0250] Table 5 - Iron reverse flotation results

[0251] The yield corresponds to the percentage by weight of the floated (froth) fraction relative to the total mass of the processed mineral pulp.

[0252] The recovery floated corresponds to the proportion of the target element (e.g., Fe or SiGM) recovered in the floated fraction, expressed as a percentage of its initial content in the feed.

[0253] The recovery tailing corresponds to the proportion of the target element remaining in the nonfloated (tailings) fraction, expressed as a percentage of its initial content in the feed.

[0254] The froth grade corresponds to the concentration (wt%) of the target element (e.g., Fe or SiGM) in the floated fraction. The tailings grade corresponds to the concentration (wt%) of the target element in the nonfloated fraction.

[0255] The results in Table 5 show that the polymers according to the invention P6, P9, PIO, and Pl 2, selectively improve silica recovery with an impact on iron loss in the tailings (float), ranging from positive to neutral and then slightly negative as the dosage increases. This also leads to an improvement in the iron content of the iron concentrate (non-floated) and the silica content of the tailings (floated).

[0256] Polymers P7, P8, and Pl 1, also according to the invention, similarly improve silica recovery in the tailings (floated) and the iron content of the concentrate (non-floated), but they are less selective than polymers P6, P9, PIO, and P12 of the invention, as a noticeable increase in iron loss in the tailings (floated) is observed at lower dosages compared to P6, P9, PIO, and P13. Polymer P5 (outside the scope of the invention) also improves silica recovery in the tailings (floated) and the iron content of the concentrate (non-floated), but causes the highest iron loss in the tailings (non-floated) of all the tests, significantly higher than the blank, demonstrating the superiority of the polymers according to the invention, particularly polymers P6, P9, PIO, and P12.

[0257] Example 4 - Direct flotation of gold and copper ores

[0258] Flotation tests were carried out using a laboratory Denver D-12 flotation cell equipped with a 4 L vessel.

[0259] The mineral pulp used was sourced from an industrial gold and copper ore flotation plant and had an initial gold (Au) content of 1.35 g / t (dry basis), a copper (Cu) content of 0.35 wt%, an iron (Fe) content of 10.1 wt%, and a silicate gangue minerals (SiGM) content of 20.8 wt%. The copper and gold are hosted in chalcopyrite and bornite.

[0260] The iron is primarily hosted in chalcopyrite, bornite, and pyrite.

[0261] An increase in iron content in a given fraction without a corresponding increase in copper content is therefore interpreted as an increase in pyrite concentration.

[0262] Silicon is hosted in quartz and the feldspar group, which represent the main gangue minerals. The pulp was first dried at 80°C for 48 hours and divided into 2000 g samples.

[0263] Each sample was resuspended in 2.5 L of tap water.

[0264] After 5 minutes of mixing under agitation at 1200 rpm, the pH was adjusted to 9.5.

[0265] Following a 2 minute conditioning period, a 1% aqueous solution of FLOMIN C 3505 collector was added at a dosage of 30 grams per tonne, a 1% aqueous solution of FLOMIN C 2430 collector was added at a dosage of 30 grams per tonne, and a 1% aqueous solution of MIBC collector was added at a dosage of 4 grams per tonne to form the conditioned pulp PCI (step a).

[0266] Following another 5 minute mixing period at 900 rpm, a solution of water-soluble polymer P9 at 10 g / L in water, was added to the flotation cell at the desired dosage to form the conditioned pulp PC2 (step b).

[0267] After 1 minute of mixing at 900 rpm, the agitation speed was reduced to 700 rpm and air was introduced in the flotation cell (step c), initiating the direct flotation and resulting in a loaded froth and a treated pulp Pt. The total flotation time was 6 minutes.

[0268] The loaded froth was recovered and redispersed in water to form a pulp Pf (step d).

[0269] A solid / liquid separation was performed on the pulp Pf to obtain solid SI (step e).

[0270] A similar separation of the treated pulp Pt yielded a solid S2.

[0271] The particle size distribution of solid SI exhibited a D80 of 80 pm.

[0272] Flotation results

[0273] Table 6 - Gold and copper direct flotation results

[0274] The results in Table 6 show that the polymers according to the invention selectively improve gold and copper recovery.

[0275] Example 5 - Double reverse flotation of phosphate

[0276] Flotation tests were carried out using a Agitair laboratory flotation cell equipped with a 1 L vessel.

[0277] Sedimentary phosphate ores were used for a two-stage reverse flotation process: an initial anionic reverse flotation of carbonates, followed by a cationic reverse flotation of silicates. The mineral pulp was sampled from an industrial phosphate flotation plant and sieved to isolate the <40 pm fraction, which is considered by the operator to be the most difficult to treat due to its low phosphate content and the poor floatability of fine particles.

[0278] The initial pulp contained 21.5 wt% phosphorus pentoxide (P2O5), 37.0 wt% calcium oxide (CaO), 4.2 wt% magnesium oxide (MgO), and 7.6 wt% silicate gangue minerals (SiGM). Phosphate is mainly carried by apatite and collophane while floated gangue minerals are silicates (quartz, microcrystalline silica, feldspars and phyllosilicates), and carbonates (calcite, dolomite).

[0279] The pulp was dried at 80 °C for 48 hours and divided into 320 g samples.

[0280] Each sample was resuspended in 580 mL of tap water. After 4 minutes of mixing at 1400 rpm, the pH was adjusted to 5 using a 5% phosphoric acid solution, which also acted as a depressant for phosphate minerals.

[0281] Following an additional 4-minute conditioning period at 1400 rpm, a sodium oleate solution collector at a concentration of 102mol / L, was added at a dosage of 650 g / t to form the conditioned pulp PCI (step a).

[0282] After a further 2-minute conditioning period at 1400 rpm, a solution of water-soluble polymer P6, prepared at 10 g / L in water, was added to the flotation cell at the desired dosage to form the conditioned pulp PC2 (step b).

[0283] After 1 minute of additional conditioning at 1400 rpm, the agitation speed was reduced to 1200 rpm, and air was introduced to initiate reverse flotation of carbonates (step c), resulting in a loaded froth and a treated pulp Pt.

[0284] The total flotation time was 5 minutes.

[0285] A solid / liquid separation was performed to obtain solid SI (step e).

[0286] The treated pulp Pt was then diluted with a final volume of 700 mL

[0287] After 2 minutes of mixing at 1400 rpm (without aeration), the pH was adjusted to 8 using a lime milk solution.

[0288] Following an additional 4-minute mixing period at 1400 rpm, a 1% aqueous solution of dodecylamine collector, prepared by diluting a 99% pure liquid, was added at a dosage of 650 g / t to form the conditioned pulp PCI (step a) of the second flotation stage.

[0289] Following a 2-minute mixing period at 1400 rpm, a solution of water-soluble polymer P6, prepared at 10 g / L in water, was added to the flotation cell at the desired dosage (step b) of the second flotation stage.

[0290] After 1 minute of further conditioning at 1400 rpm, the agitation speed was reduced to 1200 rpm and air was introduced to initiate the reverse flotation of silicate gangue minerals (step c) of the second flotation stage, resulting in a loaded froth and a final pulp.

[0291] The total flotation time was 5 minutes.

[0292] The loaded froth was recovered and redispersed in water to form a pulp Pf (step d) ) of the second flotation stage

[0293] A solid / liquid separation was performed on the pulp Pf to obtain solid SI (step e) ) of the second flotation stage.

[0294] A similar separation of the treated pulp Pt yielded a solid S2.

[0295] Flotation results

[0296] Table 7 - Phosphate double reverse flotation results

[0297] The results in Table 7 show that the polymers according to the invention selectively improve phosphate recovery.

[0298] Example 6 - Oxidized PGM ore flotation

[0299] 50 kg of a blend of oxidized ores sourced from the same platinum group metals (PGM) mine was used.

[0300] The material was crushed, then divided using a rotary splitter into samples of 2.0 kg.

[0301] The content of platinum group elements and gold, referred to by industry professionals as 4E (Pt, Pd, Rh, Au), was measured at 3.25 g / t.

[0302] PGM is mainly carried by sperrylite mineral and cooperite mineral characteristics of altered ores and to a lesser extent carried by tellurides and bismuthides, gold is native or associated with PGM bearing minerals, while gangue minerals are mainly quartz, magnetite and chabazite.

[0303] Each ore sample used for flotation testing was ground for 30 minutes in a rod mill equipped with stainless steel rods to achieve a grind size where 80% of the material passes 75 pm (D80 = 75 pm).

[0304] The flotation tests were performed using a Denver laboratory flotation cell equipped with a 4 L vessel, processing 3.2 L of aqueous mineral pulp.

[0305] The base plant conditions were as follows:

[0306] Addition of a depressant: SNF Chemquest M70, at a dosage of 80 g / t.

[0307] After 1 minute of conditioning, addition of a primary collector: SNF Chemquest CS5050, at 60 g / t.

[0308] After 5 minutes of conditioning, addition of a co-collector: reference Axis House AM 810 (hydroxamated base collector), at 10 g / t (step a).

[0309] After 3 minutes of conditioning, addition of a frother: SNF Chemquest FLOTANOL 2004, at 20 g / t.

[0310] After 1 minute of conditioning, flotation was initiated (step c).

[0311] The pH range during the tests was maintained between 9.5 and 10.0.

[0312] The total flotation time was 31 minutes. The loaded froth was recovered and redispersed in water to form a pulp Pf (step d).

[0313] A solid / liquid separation was performed on the pulp Pf to obtain solid SI (step e).

[0314] A similar separation of the treated pulp Pt yielded a solid S2.

[0315] In the example according to the invention, the hydroxamated base collector was replaced by the water-soluble polymer P6 to achieve step b. Table 8 - Oxidized PGM ore flotation results

[0316] The results in Table 8 show that the polymers according to the invention selectively improve 4E recovery.

Claims

Claims1. Method for recovering one or more valuable compounds by flotation of solid ore particles, comprising at least the following steps: a) Adding and mixing at least one collector with a mineral pulp, in order to form a conditioned pulp PCI, the mineral pulp coming from a mine or a quarry, the mineral pulp comprising water and particles of interest, the particles of interest being solid ore particles; b) Adding and mixing at least one water-soluble polymer to / with the conditioned pulp PCI, in order to form a conditioned pulp PC2, the water-soluble polymer comprising at least:- a hydrophobic monomer A, representing between 0.1 and 50 mol% of the monomers of the water-soluble polymer,- a hydrophilic monomer B, representing between 50 and 99.9 mol% of the monomers of the water-soluble polymer and chosen from the group consisting of:* hydrophilic non-ionic monomers;* hydrophilic anionic monomers; and* their mixtures; c) Direct or reverse flotation by air bubbling in the conditioned pulp PC2 in order to obtain a charged foam and a treated pulp Pt; d) Recovering the charged foam and putting an aqueous solution in order to obtain a pulp Pf; e) When step c) is a direct flotation, liquid / solid separation of the pulp Pf in order to obtain a solid SI containing one or more valuable compounds derived from the mineral pulp, or when step c) is a reverse flotation, liquid / solid separation of the treated pulp Pt in order to obtain a solid S2 containing one or more recoverable compounds coming from the mineral pulp.

2. Method according to claim 1, wherein the flotation of step c) is a reverse flotation.

3. Method according to claim 1 or 2, wherein the mineral pulp of step a) comprises between 20 and 60% by weight of solid particles, with respect to the total weight of the mineral pulp.

4. Method according to any one of claims 1 to 3, wherein the particles of interest of stepa) have a D80 of between 10 and 150 pm.

5. Method according to any one of claims 1 to 4, wherein the particle(s) of interest of step a) are chosen from the group consisting of: an iron ore, a copper ore, a cobalt ore, a lead ore, a zinc ore, a lithium ore, a phosphate ore, a gold ore, a platinoid ore, a molybdenum ore, a nickel ore, a tin ore, a tungsten ore, an ore of at least one rare earth, a tantalum ore, a niobium ore, a titanium ore, a zirconium ore, a fluorite ore, a barite ore, a potash ore, polymetallic ores, and their mixtures.

6. Method according to any one of claims 1 to 5, wherein the collector of step a) is cationic.

7. Method according to any one of claims 1 to 6, wherein the quantity of collector added to the pulp, during step a), is between 10 and 500 g / t, with respect to the total quantity of solid particles in the mineral pulp.

8. Method according to any one of claims 1 to 7, wherein the hydrophobic monomer A of the water-soluble polymer added during step b) is chosen from the group consisting of: (meth)acrylic acid esters having a chain of (i) C4-C30 alkyl, or (ii) arylalkyl having a C4-C30 alkyl and a C4-C30 aryl, or (iii) propoxylated, or (iv) ethoxylated, or (v) ethoxylated and propoxylated; alkyl aryl sulfonates having a C4-C30 alkyl and a C4-C30 aryl; mono-substituted amides of (meth)acrylamide having a chain (i) C4-C30 alkyl, or (ii) arylalkyl having a C4-C30 alkyl and a C4-C30 aryl, or (iii) propoxylated, or (iv) ethoxylated, or (v) ethoxylated and propoxylated; di -substituted amides of (meth)acrylamide having two chains chosen from among (i) C4-C30 alkyl, or (ii) arylalkyl having a C4-C30 alkyl and a C4-C30 aryl, or (iii) propoxylated, or (iv) ethoxylated, or (v) ethoxylated and propoxylated; anionic or cationic monomer derivatives of (meth)acrylamide carrying a hydrophobic chain; anionic or cationic monomer derivatives of (meth)acrylic acid carrying a hydrophobic chain; vinylpyridine; and their mixtures.

9. Method according to any one of claims 1 to 8, wherein the hydrophilic monomer B of the water-soluble polymer added during step b) is non-ionic and is chosen from the group consisting of: acrylamide, methacrylamide, N-alkylacrylamides, N-alkylmethacrylamides, N, N-dialkylacrylamides, N, N-dialkylmethacrylamides, alkoxylated esters of acrylic acid, alkoxylated esters of methacrylic acid, N-vinylpyrrolidone, N-methylol(meth)acrylamide, N- vinyl caprolactam, N-vinylformamide, N-vinyl acetamide, N-vinyl imidazole, N-vinylsuccinimide, acryloyl morpholine, glycidyl methacrylate, vinyl acetate, glyceryl methacrylate, diacetone acrylamide, methacrylic anhydride, acrylonitrile, maleic anhydride, itaconic anhydride, itaconamide, hydroxyalkyl (meth)acrylate, thioalkyl (meth)acrylate, isoprenol, alkoxylated derivatives of isoprenol, hydroxyethyl(meth)acrylates, alkoxylated derivatives of hydroxyethyl(meth)acrylates, hydroxypropyl(meth)acrylate, alkoxylated derivatives of hydroxypropyl(meth)acrylate, alkoxylated derivatives of hydroxypropyl(meth)acrylate and their mixtures.

10. Method according to one of claims 1 to 9, wherein the hydrophilic monomer B of the water-soluble polymer added during step b) is anionic and is chosen from the group consisting of: acrylic acid; methacrylic acid; dimethylacrylic acid; crotonic acid; maleic acid; fumaric acid; 3-acrylamido 3 -methylbutanoic acid; strong acid-type monomers having, for example, a sulfonic acid- or phosphonic acid-type function, such as vinylsulfonic acid, vinylphosphonic acid, allylsulfonic acid, methallylsulfonic acid, 2-methylidenepropane-l,3-disulfonic acid, 2- sulfoethylmethacrylate, sulfopropylmethacrylate, sulfopropylacrylate, allylphosphonic acid, ethylene glycol methacrylate phosphate, sulfonic styrene acid, 2-acrylamido-2-methylpropane sulfonic acid (ATBS), 2-acrylamido-2-methylpropane disulfonic acid, 3-allyloxy-2- hydroxypropane sulfonic acid, diethylallylphosphonate, carboxyethyle acrylate; water-soluble salts of these monomers like their alkaline metal salts, alkaline earth metals, or ammonium; and their mixtures.

11. Method according to any one of claims 1 to 10, wherein the hydrophilic monomer B is non-ionic, and in that the water-soluble polymer comprises between 0.1 and 25 mol% of cationic monomer.

12. Method according to any one of claims 1 to 11, wherein the water-soluble polymer is of biological or recycled origin, and in that the water-soluble polymer has a biosourced carbon content of between 5% by weight and 100% by weight with respect to the total weight of carbon in the water-soluble polymer, the biosourced carbon content being measured according to standard ASTM D6866-21, method B.

13. Method according to any one of claims 1 to 12, wherein the energy used to implement the flotation method comes from a heat pump or from renewable origin, advantageously of the wind, photovoltaic, fuel cell or lithium battery type.

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