Thionocarbamate- and lignin-collecting compositions

Abstract

The present invention relates to compositions that are stable over time in an aqueous medium and comprise thionocarbamate-derived compounds, and to the preparation method thereof. The invention also relates to aqueous collector compositions that are stable for extended periods of time and suitable for use in processes involving the froth flotation of sulfide minerals for the extraction of valuable metals, the compositions comprising compounds derived from thionocarbamate that are stable in an aqueous medium, compounds derived from mono- and dithiophosphates, stable ionic xanthate solutions and lignin.

Description

[0001] COLLECTOR COMPOSITIONS OF THIONOCARBAMATES AND LIGNIN

[0002] Technical Field

[0003] The present invention relates to aqueous collector compositions useful in froth flotation processes for the extraction of valuable metals, for direct use in the flotation processes without the need for pretreatment of the collector composition. Furthermore, the invention relates to methods for producing the aqueous collector compositions for froth flotation processes and to the use of the aqueous collector compositions in froth flotation for the separation of sulfide minerals.

[0004] The flotation process is a process that allows for the selective separation of particularly complex sulfide minerals. The conventional froth flotation process involves mixing a mineral suspension with a foaming agent in a reactor to produce a foam, where the mineral must be in the form of pre-ground and crushed fine particles. Flotation reagents are added to the suspension of fine mineral particles to maximize the separation process. These reagents include collectors and various regulators (activators, depressants, pH regulators, etc.), thus selectively increasing the hydrophobic properties of the mineral to be separated. The mineral that has become hydrophobic and connects to the air bubbles floats to the surface of the vessel, where the air bubbles form a foam rich in hydrophobic minerals.The foam is then removed from the container and the resulting minerals are separated.

[0005] The present invention relates to collector compositions whose function is to modify the hydrophobicity of minerals by adsorption onto the mineral surface. There are different types of froth flotation collectors conventionally used, along with regulators used to modify the collectors' effect on the minerals and provide greater selectivity with respect to which material should be rendered hydrophobic.

[0006] The collectors most commonly used in the industry belong to three main groups, each of which has defined characteristics, namely:

[0007] -Thionocarbamate compounds: These are oily compounds with high selectivity for sulfide minerals of copper, silver, gold, or other valued species, to the detriment of iron sulfides or other unvalued metals present. These molecules are insoluble in aqueous media and partially soluble in dithiophosphate (DTP) compounds. -Xanthate compounds: These have the ability to collect sulfide minerals in massive form without much selectivity. They are soluble in water, with low stability, from 12 to 24 hours in a 10% aqueous solution;

[0008] Mono- and dithiophosphate compounds: These are secondary esters of mono- or dithiophosphoric acid obtained by the reaction of phosphorus pentasulfide with alcohols. They are highly selective collectors, so they are used as secondary collectors for the recovery of gold and silver when associated with sulfide minerals. Although they are more soluble in water than xanthates, they are less susceptible to hydrolysis, so they can act in slightly acidic media.

[0009] In the flotation process, each of these collectors is used separately, as the sole collecting reagent in conjunction with the other flotation agents (depressants, activators, and modifiers). Their dosage is primarily carried out during the mineral grinding process (thionocarbamates) or during the mineral conditioning stage (DTP and xanthates). In flotation processes, different types of collectors can also be added to the pulp separately and sequentially to achieve higher yields. However, these processes also require sequential froth separation.

[0010] Technical problem

[0011] The chemical nature of each of the three types of collecting agents described above prevents the production of a stable, aqueous mixture. Consequently, flotation processes require different types of collectors, which must be used at different stages, with more reagents and controlling different factors / parameters at each stage. This means that more flotation stages must be carried out with a greater quantity of flotation reagents accompanying each of the collectors, which translates into higher operating costs due to the greater quantity of reagents and longer operating time on site due to the sum of stages with the different collectors.

[0012] On the other hand, until now it has not been possible to mix the different types of collectors in a simple way, since as is known, xanthates are dangerous and highly flammable products in solid state due to the generation of CS2, which forces the industry to comply with the standards for the handling of dangerous products, such as maintaining storage and distribution logistics, confinement and construction of bunkers for storage and having qualified personnel and certified facilities (anti-explosion) for daily handling, which translates into high-cost investments to minimize risks.

[0013] Thionocarbamate-derived compounds, on the other hand, are oily compounds, insoluble in aqueous media and partially soluble in dithiophosphates, which makes mixing with other collectors difficult.

[0014] The technical challenge, therefore, is to achieve stable mixtures of the different types of collectors in a simple manner to eliminate the successive steps of applying collectors separately in the flotation process, while also minimizing the risks of handling hazardous products and reducing the product's danger.

[0015] In another aspect, there is also a growing need to use biodegradable and more environmentally friendly reagents with a low carbon footprint during production, use, and disposal. Therefore, another technical challenge is the total or partial replacement of collector formulation components with environmentally friendly natural products such as natural or chemically modified biopolymers that maintain or improve metallurgical performance.

[0016] Therefore, an objective of the present invention is to overcome the aforementioned problems by providing an improved froth flotation collector composition comprising different types of collectors in the same stable liquid composition and which allows maximizing the yields in the separation of sulfide minerals, in a single flotation stage, without the need to use the different collectors in different stages.

[0017] Another objective of the present invention is to provide a froth flotation collector composition that is biodegradable and environmentally friendly, both in its production and in the processing of minerals and its disposal after being used in flotation processes, obtaining a cleaner production in the long term, improving the sustainability and performance of mining operations by reducing the impacts on the environment.

[0018] Solution to the technical problem

[0019] The objectives set forth in the present invention are achieved by means of compositions of collectors for foam flotation processes that comprise in the same stable aqueous solution three types of collectors, namely, compounds derived from thionocarbamates (T), mono or dithiophosphates (D) and xanthates (X), which correspond to the compounds most commonly used as collecting agents in flotation processes, resulting in an aqueous liquid composition with triple collecting power, ready to be applied in the foam flotation process, without the need for prior treatment, and also stable over time, for a period of 18 months or more.

[0020] The objectives of the present invention are also achieved by compositions of froth flotation process collectors comprising in the same stable aqueous solution the three types of collectors mentioned above, namely, compounds derived from thionocarbamates (T), mono or dithiophosphates (D), xanthates (X) and additionally lignin (L).

[0021] Lignin is a biopolymer found naturally in plants and trees. It is one of the most abundant natural organic molecules on Earth, second only to cellulose, and is not commonly used as a collecting agent. As an organic material, its use has little to no negative impact on the environment and it is biodegradable. Furthermore, when lignin is used, waste materials from the forestry industry can be utilized.

[0022] The collecting composition of the present invention, resulting from the combination of the three collecting agents and additionally lignin, has the characteristic of providing greater collecting capacity in order to maximize yields in the flotation process.

[0023] The combination of the three collecting agents can include different concentrations of each component depending on the type of mineral undergoing the flotation process, thereby maximizing the metallurgical performance of the flotation process and obtaining the highest yields while maintaining the operating conditions of the process. This technology offers the advantage of using only one final collector product (TDX or TDX-L technology). Therefore, the proposed technology is completely versatile, depending on the needs of the industry, and completely cutting-edge, combining three types of collectors and optionally adding lignin.

[0024] Additionally, the collector composition of the present invention, resulting from the combination of the three collecting agents and lignin, has the additional characteristic of increasing biodegradability and being more environmentally friendly.

[0025] Background of the state of the art:

[0026] The state of the art describes various flotation processes for oxidized sulfide minerals of copper, iron, and molybdenum, with the aim of optimizing the metallurgical performance of the minerals present in each of the mining operations, maintaining the separate use of the three main collecting agents described above. The use of thionocarbamates and their dosage in the grinding process has been reported, maintaining the separate dosage both in conditioning and in the advancement of the xanthates and dithiophosphate molecules, depending on the type of process and mineral processed.

[0027] Regarding thionocarbamate-derived compounds and their use as collecting agents, they are generally added to the ground and crushed material prior to flotation and are not soluble in aqueous media.

[0028] For example, document CN1 15739399 refers to collecting agents prepared by uniformly mixing different compounds such as ethoxycarbonyl hexyl thionocarbamate, benzoyl thionocarbamate, ethoxycarbonyl butyl thiourea, solvent oil and fusel ethoxycarbonylbutylthiourea until a clear, oily liquid is obtained. On the other hand, document CN1 15870101 refers to the recovery of copper and molybdenum from low-grade ores, using as a collecting agent a composition composed of light diesel, heavy diesel, naphtha, isobutanol and an allyl thionocarbamate. Neither of these documents obtains aqueous compositions of compounds derived from thionocarbamates that are miscible in an aqueous medium.

[0029] Document W02016008554 discloses a collector composition in the form of a stable aqueous emulsion comprising thionocarbamate derivatives, by using a mixture of surfactants.

[0030] In the state of the art, no process is disclosed in which soluble and stable thionocarbamate-derived compounds are obtained in an aqueous medium by means of an innovative stabilization process as disclosed in the present invention, such that the thionocarbamate-derived compounds can be included in aqueous solutions with other collecting agents to be used jointly in the froth flotation process.

[0031] The state of the art suggests that the use of a combination of collecting agents provides greater efficiency in metal recovery processes, improving yields. However, no composition is disclosed that includes, in the same aqueous solution, collecting agents derived from thionocarbamate compounds, dithiophosphates, and xanthates, much less that these aqueous solutions are stable over extended periods of time. For example, document ES2637138 discloses the possibility of using three types of collecting agents, which are added sequentially to the mineral pulp.

[0032] On the other hand, document CN11 1940149 discloses a flotation agent comprising, as a collecting agent, an alkyl xanthate derivative compound and a compound called "black medicine", together with amines, hydrofluoric acid, oxalic acid carboxylic acid, and water. Although this document produces an aqueous flotation agent, the description does not mention the presence of compounds derived from thionocarbamates or thiophosphates.

[0033] Document CN10631 148 also discloses a flotation agent consisting of butyl xanthate and a compound called "butylammonium black medicine," along with acids such as lauric acid, palmitoleic acid, maleic anhydride, acrylic acid, among other compounds, and water. Although the mixture disclosed in this document is an aqueous mixture, the presence of compounds derived from thionocarbamates or thiophosphates is not disclosed.

[0034] Document CN1 1233765 refers to a collecting agent for copper sulfide mineral flotation that includes isobutyl butoxycarbonyl thiocarbamate, methyl xanthate, "butyl ammonium black medicine," diesel oil, among other components. This document does not disclose stable aqueous compositions of solutions comprising dithiophosphate derivatives.

[0035] On the other hand, WO2021 / 052939 refers to a collector consisting of lignin particles and isobutylxanthate as a conventional collector. However, this document mixes lignin particles with a xanthate-derived compound.

[0036] Although in the state of the art, there is a constant need to maximize foam flotation processes, it has not been possible until now to obtain a collecting composition that comprises the different collecting agents already mentioned and that has the characteristics of the collecting compositions of the present invention.

[0037] Description of the invention

[0038] One aspect of the present invention relates to stable liquid collector compositions ready for use in froth flotation processes, comprising collector compounds derived from thionocarbamates, mono- or dithiophosphates, and xanthates. Another aspect of the present invention relates to stable liquid collector compositions ready for use in froth flotation processes, comprising collector compounds derived from thionocarbamates, mono- or dithiophosphates, xanthates, and lignin.

[0039] Another aspect of the present invention relates to a process for obtaining aqueous solutions of compounds derived from thionocarbamates that are soluble and stable in an aqueous medium, to be mixed with collectors derived from mono or dithiophosphates, xanthates and lignin in an aqueous medium and stable over time.

[0040] Another aspect of the present invention relates to the use of aqueous compositions of stable xanthates in aqueous medium, such as ethyl (EXS), isopropyl (IPXS), isobutyl (IBXS) and amyl (PAX) xanthates, and salts thereof according to international publication WO2023 / 193122 A1 which is incorporated in its entirety by reference in the present specification, to be mixed with solutions of compounds derived from thionocarbamates that are soluble and stable in aqueous medium, mono or dithiophosphates and lignin.

[0041] Another aspect of the present invention relates to the incorporation of lignin into collector compositions. This biopolymer is naturally found in plants and trees and is one of the most abundant natural organic molecules on Earth, second only to cellulose. As an organic material, its use has little to no negative impact on the environment and is biodegradable. Furthermore, when lignin is used, waste materials from the forestry industry can be utilized.

[0042] Description of the figures:

[0043] Figure 1: corresponds to the 13C NMR graph of the thionocarbamate derivative isopropylethyl thionocarbamate.

[0044] Figure 2: corresponds to the 13C NMR graph of ethylene glycol

[0045] Figure 3: corresponds to the 13C NMR graph of methanol.

[0046] Figure 4: corresponds to the 13C NMR graph, at time 0 (upper graph) and after 18 months (lower graph), for the product corresponding to the collector composition comprising functionalized isopropylethyl thionocarbamate, ethylene glycol, methanol, obtained in the thionocarbamate functionalization process. Figure 5: corresponds to the 1H NMR graph of the thionocarbamate derivative isopropylethyl thionocarbamate.

[0047] Figure 6: corresponds to the 1 H NMR graph of ethylene glycol

[0048] Figure 7: corresponds to the 1 H NMR graph of methanol.

[0049] Figure 8: corresponds to the 1 H NMR graph, at time 0 (upper graph) and after 18 months (lower graph) for the product corresponding to the collector composition comprising functionalized isopropylethyl thionocarbamate, ethylene glycol, methanol, obtained in the thionocarbamate functionalization process.

[0050] Detailed description of the invention

[0051] The present invention is directed to collecting compositions for the froth flotation process, which are aqueous compositions stable for a period of 18 months or more, ready for use in the froth flotation process. These collecting compositions consist of collecting agents corresponding to compounds derived from thionocarbamates, mono- or dithiophosphates, and xanthates.

[0052] Additionally, the collecting compositions of the present invention may include lignin as an additional collecting agent.

[0053] The lignin can be Kraft lignin, sodium lignin, organosolv lignin, steam explosion lignin, enzymatic hydrolysis lignin, or unhydrolyzed Kraft black liquor lignin. The present invention preferably uses high-purity Kraft lignin (Lineo™ Prime W, by Stora Enso).

[0054] Given the difference in the chemical nature of each of the collecting agents, it is required that all of them be soluble in an aqueous medium in order to form stable aqueous mixtures for long periods of time, so that they can be stored safely and used directly in the froth flotation process, without the need for any prior treatment.

[0055] The difference in the chemical nature of the collectors provides different collecting power, so the collector compositions of the present invention combine the different collecting powers to obtain compositions more efficient in performance and operating time. Particularly, the thionocarbamate-derived compounds are oily liquid organic reagents, slightly soluble or insoluble in water, very soluble in non-ionogenic organic solvents, which are particularly used in flotation circuits in a pH range of 4 to 12 for the recovery of copper, silver, gold and nickel. These compounds are generally added in the mineral grinding stage. Thionocarbamates generally have lower collecting power than xanthates, however, they present greater selectivity in the flotation of copper sulfides and oxidized copper species.

[0056] Due to their nature, it is unexpected to be able to combine thionocarbamate-derived compounds with other water-soluble collecting reagents to obtain aqueous liquid compositions of water-soluble nature.

[0057] The thionocarbamate derivative compounds used in the present invention are selected from isopropyl ethyl thionocarbamate, methyl-N-benzyl dithiocarbamate, isobutyl methyl thionocarbamate.

[0058] To carry out the present invention, ionic xanthates selected from sodium ethyl xanthate, sodium isopropyl xanthate, sodium isobutyl xanthate and potassium amyl xanthate, ionic and stabilized in aqueous solution with C2-C6 lower alcohols and nitrogen compounds selected from monoethanolamine, diethanolamine and triethanolamine, have been used in accordance with the technology disclosed in the international publication WO2023 / 193122 which is incorporated in the present description in its entirety.

[0059] Mono- or dithiophosphate (DTP) derivatives are less powerful collectors than xanthates, so when used individually, they must be used in higher doses than xanthates. They are more soluble in water than xanthates, however, they are highly selective, so they are generally used as secondary collectors in gold and silver recovery processes. Among the mono- or dithiophosphate derivatives are, for example, sodium dibutyl dithiophosphate, sodium diethyl dithiophosphate, sodium diisopropyl dithiophosphate, sodium diisobutyl dithiophosphate, sodium di-sec-butyl dithiophosphate and sodium monothiophosphate.

[0060] For its part, lignin is not known to be a collecting agent, but has been used as a dispersing agent, and particularly modified lignins such as lignosulfonate have been used as a depressing agent in flotation processes, but not as a collecting agent. In order to produce the stable aqueous collecting compositions of the present invention, it has been necessary to modify the insoluble nature of the thionocarbamate compounds by means of a process prior to mixing the collecting agents, a process that has been called chemical functionalization of the thionocarbamate-derived compounds. In this process, it has been possible to stabilize said compounds in stable aqueous solutions to subsequently mix them with the water-soluble collecting agents corresponding to the xanthate and dithiophosphate derivatives.

[0061] Functionalization process of Thionocarbamates:

[0062] The stabilization of thionocarbamate compounds in an aqueous medium is carried out in a stainless steel reactor by mixing the thionocarbamate derivative or mixtures of thionocarbamate derivatives with glycol derivative compounds, at a temperature between 0 and 50°C, more preferably between 25 and 40°C, with constant stirring between 30 and 100 rpm for a period of 30 to 60 minutes. The glycols used are mainly of low molecular weight, preferably ethylene glycol, diethylene glycol, propylene glycol, or mixtures thereof), and can be incorporated in 1 to 60 parts of the total weight of the composition and more particularly the amount of the glycol derivative is 20, 25, 30, 35 or 40 parts of the total weight of the composition. The reaction is carried out in a pH range of 3 to 7.

[0063] The thionocarbamate compounds are selected from isopropyl ethylthionocarbamate (IPETC), methyl-N-benzyldithiocarbamate, isobutyl methylthionocarbamate, diethylthionocarbamate, N-allyl-O-lsobutylthionocarbamate, and may be incorporated in 1 to 90 parts of the total weight of the composition and more particularly the amount of the thionocarbamate derivative is 30, 40, 50, 60 or 70 parts of the total weight of the composition.

[0064] To the thionocarbamate compound or a mixture of thionocarbamate-derived compounds and glycol, one or more lower alcohols Ci-Ce, selected from methanol, ethanol, propanol, butanol, pentanol, and hexanol, preferably methanol, are added. The mixture is stirred for a period of 30 to 90 minutes, until reaction and complete homogenization, maintaining a temperature below 40°C. The lower alcohols can be incorporated in 1 to 60 parts of the total weight of the composition, and more particularly the amount of the lower alcohol is 15, 20, 25, 30, 35 or 40 parts of the total weight of the composition.

[0065] The composition thus obtained is then cooled to room temperature and discharged into a storage container. Example 1

[0066] Example 1A: Functionalization of the compound isopropylethyl thionocarbamate

[0067] In a stainless steel reactor, 50 parts of isopropylethyl thionocarbamate (T1) and 25 parts of ethylene glycol are added, controlling the pH conditions between 3 and 7, with a sample obtained from the reactor, and the pH value is recorded using a peachimeter (METTLER TOLEDO or HACH), mixing with constant stirring between 30 and 100 rpm for a period of 30 to 60 minutes. The reaction is maintained at a temperature of 25 to 40 ° C. To the previous mixture, 25 parts of methanol are added and stirred for a period of 30 to 90 minutes, until complete reaction and homogenization, maintaining a temperature of 40 ° C). It is then cooled to room temperature and discharged into a storage container.

[0068] Example 1 B: Functionalization of the compound methyl N-benzyl dithiocarbamate

[0069] In a stainless steel reactor, 60 parts of methyl N-benzyl dithiocarbamate (T2) and 20 parts of ethylene glycol are added, controlling the pH conditions between 3 and 7, with a sample obtained from the reactor, and the pH value is recorded using a peachimeter (METTLER TOLEDO or HACH), mixing with constant stirring between 30 and 100 rpm for a period of 30 to 60 minutes. The reaction is maintained at a temperature of 25 to 40 ° C. To the previous mixture, 20 parts of methanol are added and stirred for a period of 30 to 90 minutes, until complete reaction and homogenization, maintaining a temperature of 40 ° C). It is subsequently cooled to room temperature and discharged into a storage container.

[0070] Example 1 C: Functionalization of the compound isobutyl methyl thionocarbamate

[0071] In a stainless steel reactor are added 40 parts of isobutyl methyl thionocarbamate (T3), 30 parts of ethylene glycol, controlling the pH conditions between 3 and 7 (with a sample obtained from the reactor, and the pH value is recorded by a peachimeter, (METTLER TOLEDO or HACH), mixing with constant stirring between 30 and 100 rpm for a period of 30 to 60 minutes. The reaction is maintained at a temperature of 25 to 40 ° C. To the previous mixture are added 30 parts of methanol and stirred for a period of 30 to 90 minutes, until complete reaction and homogenization, maintaining a temperature of 40 ° C). Subsequently, it is cooled to room temperature and discharged into a storage container. Table 1 shows the characterization of the functionalized thionocarbamates, T1, T2 and T3.

[0072] Table 1: Characterization of different productions of functionalized thionocarbamates

[0073] The results in Table 1 show that the solutions obtained with different functionalized thionocarbamate derivatives T1, T2 and T3 have very similar densities, being stable between pH 4.2 and 4.5.

[0074] The electrochemical potential parameter demonstrates no significant difference between the two processes. Products with electrochemical potentials greater than 400 can act as copper depressants, which would be contrary to the collector effect intended in the present invention.

[0075] On the other hand, the electrical conductivity values ​​demonstrate the ionic mobility of the solution, which implies the presence of polar components that make the product miscible in water.

[0076] The color measurements and the percentages of C and N represent reference values ​​for the quality control of the products obtained in the functionalization process of thionocarbamate compounds.

[0077] The mixtures obtained correspond to solutions of stable, crystalline and transparent Functionalized Thionocarbamate compounds for at least 18 months, completely soluble in water or polar components.

[0078] To determine the stability of the obtained solutions, 13C NMR and 1H NMR analyses were performed. Figures 4 and 8 are a representative sample of the 13C NMR and 1H NMR spectra obtained at time 0 and after 18 months, of isopropylethyl thionocarbamate functionalized (T1 ) with ethylene glycol, methanol, resulting in identical spectra at the two measured times, confirming that the products obtained by the thionocarbamate functionalization process are stable products, at least over a proven period of 18 months, allowing their storage and subsequent use without altering the metallurgical results.

[0079] The solution of functionalized Thionocarbamate compounds according to the examples of the present invention are used as raw material to prepare the collecting agent compositions of the present invention, which contemplates the reaction and stabilization with aqueous solutions of stable ionic liquid xanthate, mono or dithiophosphates and additionally lignin.

[0080] Process for preparing collector compositions comprising derivatives of thionocarbamates, xanthates and mono or dithiophosphates and optionally lignin (TDX)

[0081] The process of preparing the collector compositions comprising derivatives of thionocarbamates, xanthates and mono or dithiophosphates of the present invention is carried out in a stainless steel reactor, provided with cooling jackets, condensers and agitators.

[0082] The process comprises the following stages:

[0083] - Load the reactor with the functionalized thionocarbamate composition (obtained according to example 1 ), at room temperature, stirring at a stirring speed between 30 and 100 rpm, preferably between 50 to 70 rpm. The reactor temperature is maintained between 10 and 50° C, preferably 20 to 30° C. The proportions of thiocarbamate added to the reactor are from 1 to 90 parts by weight of the total composition, and more particularly 10, 20, 30, 40, 50, 60, 70, 80, 90 parts by weight of the total composition.

[0084] - Filling the reactor with a compound derived from mono or dithiophosphate; in proportions of 1 to 90 parts by weight of the total composition, and more particularly 10, 20, 30, 40, 50, 60, 70, 80, 90 parts by weight of the total composition. The addition of the dithiophosphate or monothiophosphate compounds is carried out over a period of 30 to 120 minutes, preferably between 45 and 70 minutes, maintaining the temperature preferably between 20 and 35°C, with constant stirring between 50 and 70 rpm.- Load the reactor with the stable ionic xanthate solution in aqueous solution (prepared according to international publication WO2023 / 193122 A1 ), in proportions of 10 to 90 parts by weight of the total composition, and more particularly 20, 30, 40, 50, 60, 70, 80, 90 parts of the total composition, in a period of time of 30 to 90 minutes, preferably 40 to 55 minutes, maintaining the reaction temperature stable and not higher than 35°C, with constant stirring between 50 to 70 rpm.

[0085] - Optionally, load the reactor with lignin, in proportions of 1 to 90 parts by weight of the total composition, and more particularly 20, 30, 40, 50, 60, 70, 80, 90 parts of the total composition, in a period of time of 30 to 90 minutes, preferably 40 to 55 minutes, maintaining the reaction temperature stable and not higher than 35°C, with constant stirring between 50 to 70 rpm.

[0086] - Finally, cool to room temperature and package.

[0087] The product resulting from the process described above corresponds to a combination of the three types of collectors, in a stable, crystalline solution, with triple collector power (TDX Technology).

[0088] Additionally, the product resulting from the process described above corresponds to a combination of the three types of collectors together with lignin, in a stable, crystalline solution, with triple collecting power (TDX-L Technology).

[0089] Example 2:

[0090] Preparations of collector compositions with TDX and TDXL

[0091] A. Preferred Embodiments of Preparation of TDX Collector Composition

[0092] The TDX collector composition preparation process is carried out in a stainless steel reactor, equipped with cooling jackets, condensers and agitators.

[0093] The process comprises the following stages:

[0094] - Load the reactor at room temperature with the selected thionocarbamate compound from:

[0095] T 1 : functionalized isopropylethyl thionocarmabate obtained in Example 1 A; or

[0096] T2: Functionalized methyl N-benzyl dithiocarbamate obtained in Example 1 B; or T3: Functionalized isobutyl methyl thionocarbamate obtained in Example 1 C.

[0097] The product added to the reactor is stirred at a speed of 50 to 70 rpm. The reactor temperature is maintained between 10 and 50°C.

[0098] - Load the reactor with the mono or dithiophosphate compound selected from:

[0099] D1: sodium diisobutyl dithiophosphate

[0100] D2: sodium diethyl dithiophosphate

[0101] D3: sodium diisopropyl dithiophosphate

[0102] D4: sodium dibutyl dithiophosphate

[0103] D5: sodium disecbutyl dithiophosphate

[0104] D6: sodium mono thiophosphate

[0105] The addition of the mono or dithiophosphate compound is carried out over a period of 30 to 120 minutes, maintaining the temperature preferably between 20 and 35°C, with constant stirring between 50 and 70 rpm.

[0106] - Charge the reactor with a stable ionic xanthate solution, selected from: X1: sodium isopropyl xanthate, stable ionic liquid

[0107] X2: Sodium ethyl xanthate, stable ionic liquid X3: Sodium isobuyl xanthate, stable ionic liquid X4: Potassium amyl xanthate, stable ionic liquid

[0108] The addition of the stable ionic xanthate solution is carried out over a period of 40 to 55 minutes, keeping the reaction temperature stable and not exceeding 35°C, with constant stirring between 50 to 70 rpm.

[0109] With the additional purpose of studying the metallurgical performance of the compositions of the invention (TDX technology) compared to a composition that also includes lignin, the TDX-L compositions of Examples 15, 16, 17 and 18 were prepared, to determine the behavior of this constituent in the group of TDX compositions described in Table 2. In this case, 15 parts of lignin (LineoTM Prime W, by Stora Enso) were added, over a period of 40 to 55 minutes, keeping the reaction temperature stable and not exceeding 35 ° C, with constant stirring between 50 to 70 rpm. The lignin can be added directly, that is, in solid form (powder), or dissolved in water at a pH between 2 and 13.

[0110] Table 2 illustrates the different formulations of the collector compositions of the present invention prepared according to the process described above, indicating the proportions of each of the collectors. A representative selection of the compositions in Table 2 were subsequently evaluated in a laboratory froth flotation method to determine the percentage of metal recovery.

[0111] Table 2:

[0112] Examples of embodiments of the TDX collector compositions of the present invention Table 3:

[0113] Chemical characterization of a representative selection of the TDX collector compositions of the present invention with the composition T1-D1-X1 in different proportions

[0114] B. Preferred embodiments of preparing TDX-L collector composition

[0115] The TDX-L collector composition preparation process is carried out in a stainless steel reactor, equipped with cooling jackets, condensers and agitators.

[0116] The process comprises the following stages:

[0117] - Load the reactor at room temperature with the selected thionocarbamate compound from:

[0118] T 1 : functionalized isopropylethyl thionocarmabate obtained in Example 1 A; or

[0119] T2: Functionalized methyl N-benzyl dithiocarbamate obtained in Example 1 B; or

[0120] T3: Functionalized isobutyl methyl thionocarbamate obtained in example 1C.

[0121] The product added to the reactor is stirred at a speed of 50 to 70 rpm. The reactor temperature is maintained between 10 and 50°C.

[0122] - Load the reactor with the mono or dithiophosphate compound selected from:

[0123] D1: sodium diisobutyl dithiophosphate

[0124] D2: sodium diethyl dithiophosphate

[0125] D3: sodium diisopropyl dithiophosphate

[0126] D4: sodium dibutyl dithiophosphate

[0127] D5: sodium disecbutyl dithiophosphate

[0128] D6: sodium monothiophosphate The addition of the mono or dithiophosphate compound is carried out over a period of 30 to 120 minutes, maintaining the temperature preferably between 20 and 35°C, with constant stirring between 50 and 70 rpm.

[0129] - Charge the reactor with a stable ionic xanthate solution, selected from:

[0130] X1: sodium isopropyl xanthate, stable ionic liquid

[0131] X2: Sodium ethyl xanthate, stable ionic liquid

[0132] X3: Sodium isobutyl xanthate, stable ionic liquid

[0133] X4: Potassium amyl xanthate, stable ionic liquid

[0134] The addition of the stable ionic xanthate solution is carried out over a period of 40 to 55 minutes, keeping the reaction temperature stable and not exceeding 35°C, with constant stirring between 50 to 70 rpm.

[0135] - Load the reactor with “L” lignin (LineoTM Prime W, by Stora Enso), in a period of 40 to 55 minutes, keeping the reaction temperature stable and not exceeding 35°C, with constant stirring between 50 to 70 rpm.

[0136] Table 4 illustrates the different formulations of the collector compositions of the present invention with the additional lignin component, prepared according to the process described above, indicating the proportions of each of the collectors.

[0137] A representative selection of the compositions in Table 4 were subsequently evaluated in a laboratory froth flotation method to determine the percentage of metal recovery.

[0138] Table 4:

[0139] Examples of embodiments of the TDX-L collector compositions of the present invention

[0140]

[0141] Table 5:

[0142] Chemical characterization of a representative selection of the TDX-L collector compositions of the present invention

[0143] The results in Tables 3 and 5 provide a chemical characterization of a selection of the compositions obtained with the stable thionocarbamate derivatives, mono or dithiophosphate and ionic xanthate are stable aqueous solutions miscible in water with and without lignin. All the solutions obtained have densities close to 1. These solutions are also safe and non-corrosive in accordance with our current legislation, since they all register pH values ​​around 12. On the other hand, the results with low electrical conductivity values ​​​​indicate that these solutions do not contribute greater polarity and ions to the mineral to be recovered. With respect to the refractive index (nD), it is a necessary value to determine in the quality control of the final product.

[0144] Metal recovery tests using the TDX and TDX-L compositions of the present invention:

[0145] To evaluate the metallurgical performance of the compositions of the present invention, various flotation processes were performed using the most representative stable aqueous TDX and TDX-L compositions of the present invention as collectors. These compositions were stored for 18 months from their preparation until their use in the froth flotation process. To determine their efficiency, flotation processes were performed using standard reagents.

[0146] The tests were designed to scale with an evaluation system validated in a simulated environment using laboratory metallurgical flotation cells with Rougher flotation equipment.

[0147] Tables 6 and 7 show the results obtained in the flotation processes carried out in the laboratory with the most representative compositions of TDX and TDX-L obtained in the present invention.

[0148] The Concentrate corresponds to the foam overflow obtained in the flotation process to obtain the maximum recovery of metals (Cu, Fe, Mo), the higher the concentrate grade, the greater the recovery.

[0149] Tailings are the minerals left at the end of the flotation process. In an efficient process, the tailings should contain a minimal amount of copper.

[0150] Recovery corresponds to 100% recovered metal, with respect to the initial grade of dry mineral.

[0151] The head corresponds to the theoretical ore grade obtained from experimental recovery data. This value is very close to the analyzed dry ore grade.

[0152] In the froth flotation process performed with TDX compatibilities, the sodium isopropyl xanthate (SIPX) collector (5%) was used as a control in combination with diesel. SIPX is the most widely used xanthates collector in flotation operations due to its high collecting power, making it an excellent comparison standard. In the froth flotation process performed with TDX-L compatibilities, a standard collector (modified dithiocarbamate) was used as a control in combination with diesel.

[0153] The foaming agents used in the tests of the present invention correspond to standard foaming agents widely used in flotation processes.

[0154] In both the TDX and TDX-L flotation processes of the present invention, Diesel was used as a universal Molybdenum collector, maintaining the same operating conditions.

[0155] The results obtained in Table 6 of the TDX compositions of the present invention compared to the standard demonstrate a better performance in the percentage of Cu recovery, in the order of 10 to 12% more than the standard. However, it is observed that the percentages of Fe recovery are not as high as with Cu, reaching in some cases up to 4% more Fe recovery compared to the standard, and in some cases, particularly with TDX-L-3, less Fe is recovered than the standard, which indicates that the TDX and TDXL compositions are highly selective collector compositions recovering less Fe and more Cu.

[0156] Furthermore, the results show that the percentage of copper in the concentrate with the TDX and TDX-L compositions of the present invention is higher than that observed with the standard or control, and it includes less Fe as an impurity. This fact is very important, since copper concentrate is the commercial product traded by the mining industry.

[0157] In addition to the advantages of greater copper recovery and greater selectivity, the compositions of the present invention, both the TDX and TDX-L compositions, can present results with less mass recovery, which is explained by their high iron selectivity, resulting in a very important contribution to the mining operation, since collector consumption can be increased to increase the mass of mineral that needs to be recovered, maintaining a high percentage of copper recovery and low iron recovery.

[0158] Therefore, the advantages provided by the stable, aqueous TDX and TDX-L compositions of the present invention allow the compositions with the collector mixtures to be used directly in the froth flotation process without the need for prior treatment of the flotation reagent, and in a single stage, without performing different flotation stages with the different collectors, unlike conventional processes. In this way, it is possible to obtain a high degree of selectivity of the metals to be recovered, as well as high metal recovery percentages, which are extremely significant at an industrial level.

[0159] Table 6

[0160] Results obtained in the flotation process with each of the TDX compositions of the present invention compared with a standard (SiPX)

[0161] Table 7

[0162] Results obtained in the flotation process with each of the TDX-L compositions of the present invention compared with a standard (MATCOL)

Claims

CLAIMS 1. Stable composition over time, in an aqueous medium, of compounds derived from thionocarbamate, CHARACTERIZED in that the composition comprises: - thionocarbamate derivative compound or mixtures of thionocarbamate derivative compounds, - a low molecular weight glycol and - a lower alcohol Ci-Ce.

2. The composition according to claim 1, CHARACTERIZED in that the thionocarbamate derivative compound is selected from isopropyl-ethylthionocarbamate (IPETC), methyl-N-benzyldithiocarbamate, isobutyl-methylthionocarbamate, diethylthionocarbamate, N-allyl-O-lsobutyl-thionocarbamate.

3. The composition according to claim 1, CHARACTERIZED in that the low molecular weight glycol is selected from ethylene glycol, diethylene glycol, propylene glycol.

4. The composition according to claim 1, CHARACTERIZED in that the lower alcohol Ci-Ce is selected from methanol, ethanol, propanol, butanol, pentanol, and hexanol.

5. The composition according to the preceding claims, CHARACTERIZED in that the amount of the thionocarbamate derivative compound is 30, 40, 50, 60 or 70 parts of the total weight of the composition.

6. The composition according to the preceding claims, CHARACTERIZED in that the amount of low molecular weight glycol is 20, 25, 30, 35 or 40 parts of the total weight of the composition.

7. The composition according to the preceding claims, CHARACTERIZED in that the amount of the lower alcohol Ci-Ce is 15, 20, 25, 30, 35 or 40 parts of the total weight of the composition.

8. Process for preparing the composition stable over time, in an aqueous medium, of thionocarbamate-derived compounds according to claim 1, CHARACTERIZED in that it comprises the steps of: Loading into a stainless steel reactor the thionocarbamate derivative in an amount between 1 and 90 parts relative to the total weight of the composition and the glycol compound in an amount between 1 and 60 parts of the total weight of the composition; mixing with constant stirring between 30 and 100 rpm for a period of 30 to 60 minutes, at a temperature of 25 to 40°C; adding to the previous mixture 1 to 60 parts of the lower alcohol Ci-Ce; stirring the resulting mixture for a period of 30 to 90 minutes, until the reaction and homogenization are complete, maintaining a temperature below 40°C. Cool to room temperature and store.

9. Process for preparing the composition according to claim 8, CHARACTERIZED in that the thionocarbamate derivative is selected from isopropyl-ethylthionocarbamate (IPETC), methyl-N-benzyldithiocarbamate, isobutyl-methylthionocarbamate, diethylthionocarbamate, N-allyl-O-lsobutyl-thionocarbamate.

10. Process for preparing the composition according to claim 8, CHARACTERIZED in that the low molecular weight glycol is selected from ethylene glycol, diethylene glycol, propylene glycol. 1 1. Process for preparing the composition according to claim 8, CHARACTERIZED in that the lower alcohol Ci-Ce is selected from methanol, ethanol, propanol, butanol, pentanol, and hexanol.

12. Collector composition stable over time, in an aqueous medium and ready to be used as a collector reagent in the flotation process CHARACTERIZED in that it comprises: a composition stable over time and in an aqueous medium of a thionocarbate derivative compound, a low molecular weight glycol and a lower alcohol CrCe; a compound derived from mono or dithiophosphate; a solution of an ionic xanthate compound stable in aqueous solution.

13. Collector composition according to claim 12 CHARACTERIZED in that it also comprises lignin.

14. Collector composition according to claim 13 CHARACTERIZED in that the lignin is high purity Kraft lignin.

15. Collector composition according to claims 12 to 14, CHARACTERIZED in that the thionocarbamate derivative compound included in the composition stable over time and in an aqueous medium is selected from isopropyl-ethylthionocarbamate (IPETC), methyl-N-benzyldithiocarbamate, isobutyl-methylthionocarbamate, diethylthionocarbamate, N-allyl-O-lsobutyl-thionocarbamate.

16. Collector composition according to claims 12 to 15, CHARACTERIZED in that the compound derived from mono or dithiophosphate is selected from sodium dibutyl dithiophosphate, sodium diethyl dithiophosphate, sodium diisopropyl dithiophosphate, sodium diisobutyl dithiophosphate, sodium di-sec-butyl dithiophosphate and sodium monothiophosphate.

17. Collector composition according to claims 12 to 16 CHARACTERIZED in that the xanthate compound included in the stable ionic xanthate solution in aqueous solution is selected from sodium isopropyl xanthate, sodium ethyl xanthate, sodium isobuyl xanthate and potassium amyl xanthate.

18. Process for preparing the collector composition that is stable over time, in an aqueous medium and ready to be used as a collector reagent in the flotation process according to claim 12, CHARACTERIZED in that it comprises the steps of: - loading a reactor with 1 to 90 parts by weight of the total composition with the composition stable over time and in an aqueous medium comprising the thionocarbate derivative compound, the low molecular weight glycol and the lower alcohol Ci-Ce, at room temperature, stirring at a stirring speed between 30 and 100 rpm, and maintaining the reactor temperature between 10 and 50° C; - load the reactor with 1 to 90 parts by weight of the total composition, with a compound derived from mono or dithiophosphate, in a period of time of 30 to 120 minutes, maintaining the temperature between 20 and 35°C, with constant stirring between 50 to 70 rpm; - loading the reactor with 10 to 90 parts by weight of the total composition with the stable ionic xanthate solution in aqueous solution over a period of time from 30 to 90 minutes, keeping the reaction temperature stable and not exceeding 35°C, with constant stirring between 50 to 70 rpm. - optionally load the reactor with lignin, in proportions of 1 to 90 parts by weight of the total composition, in a period of time of 30 to 90 minutes, keeping the reaction temperature stable and not exceeding 35°C, with constant stirring between 50 to 70 rpm.

19. Preparation process according to claim 18, CHARACTERIZED in that the thionocarbamate derivative compound included in the composition stable over time and in an aqueous medium is selected from isopropyl-ethylthionocarbamate (IPETC), methyl-N-benzyldithiocarbamate, isobutyl-methylthionocarbamate, diethylthionocarbamate, N-allyl-O-lsobutyl-thionocarbamate.

20. Preparation process according to claims 18 and 19 CHARACTERIZED in that the compound derived from mono or dithiophosphate is selected from sodium dibutyl dithiophosphate, sodium diethyl dithiophosphate, sodium diisopropyl dithiophosphate, sodium diisobutyl dithiophosphate, sodium di-secbutyl dithiophosphate and sodium monothiophosphate.

21. Preparation process according to claims 18 to 20, CHARACTERIZED in that the xanthate compound included in the stable ionic xanthate solution in aqueous solution is selected from sodium isopropyl xanthate, sodium ethyl xanthate, sodium isobuyl xanthate and potassium amyl xanthate.

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