Flotation separation method for tremolite-containing minerals

Abstract

The invention discloses a flotation separation method for tremolite-containing minerals, and belongs to the technical field of mineral separation. The method comprises the following steps: S1, grinding and dissociating raw ore containing tremolite minerals, and adding a combined modification regulator in the grinding and dissociating process to obtain ore pulp A; s2, the ore pulp A is mixed and stirred, a strong electrolyte regulator is added in the stirring process, and ore pulp B is obtained; and S3, a first collecting agent is added into the ore pulp B, flotation separation is conducted on the tremolite-containing minerals, and a product C containing the tremolite minerals and ore pulp D containing target minerals are obtained. According to the method, the flotation separation process is adopted, flotation is preferentially conducted on the tremolite-containing minerals, selective separation of the tremolite-containing minerals and target minerals is achieved, and the negative influence of the iron-containing gangue minerals on mineral separation is reduced.

Description

Technical Field

[0001] This invention relates to the field of mineral processing technology, and in particular to a flotation separation method for iron-bearing amphibole minerals. Background Technology

[0002] The general chemical formula of amphibole group minerals is A 0-1 X2Y5[T4O 11 ]2(OH,F,Cl)2, where A represents Na + Ca 2+ K + H3O + X represents Na + Li + K + Ca 2+ Mn 2+ Fe 2+ Y represents Mg 2+ Fe 2+ Mn 2+ Al 3+ Fe 3+ Ti 4+ Cr 3+ T represents Si 4+ Al 3+ Ti 4+ Amphibole minerals are among the most widely distributed rock-forming minerals. They are a group of double-chain silicate minerals whose crystals often belong to the orthorhombic or monoclinic crystal systems. They are mostly found in metamorphic and igneous rocks, formed by the metamorphism / alteration of rocks rich in iron, magnesium, and calcium minerals, resulting in silicate or aluminosilicate minerals rich in calcium, magnesium, iron, sodium, and aluminum, such as common amphibole (Ca, Na). 2-3 [Mg,Fe(II),Fe(III),Al]4[(Al,Si)8O 22 ](OH)2, tremolite Ca2(Mg,Fe)5(Si4O 11 (OH)2, Actinolite Ca2(Mg,Fe)5Si8O 22 (OH)2, sodium amphibole Na2Fe3Fe2[Si4O 11 ]2(OH)2, Blue glaze Na2(Mg,Fe)3Al2Si8O 22 (OH)2, etc. Because these minerals have similar crystal structures to the target minerals to be separated and recovered in the ore (such as spodumene, diopside, etc.), and similar physical properties of their dissociated surfaces, and are often inevitably adsorbed by metal ions in the flotation system, their surface charge properties become more similar to those of the target minerals. As a result, they have become one of the key gangue minerals affecting the quality of concentrates and the separation efficiency of various types of oxide minerals.

[0003] Currently, in the processing and sorting of oxide minerals, due to the inherent physicochemical properties and complex occurrence state of spodumene ore, there are relatively few reports on beneficiation technologies for the selective separation or removal of amphibole groups. Reported sorting methods with relative mineral selectivity include sorting based on differences in mineral magnetic, photoelectric, and surface physicochemical properties, specifically including:

[0004] (1) Utilizing the weak magnetic properties of Fe-containing amphibole minerals, a combined process of weak magnetic separation and strong magnetic separation is used to separate these minerals. For example, in the process of separating spodumene ore, combined processes such as flotation-magnetic separation and magnetic separation-flotation are used. Chinese patent CN109107754B discloses a combined magnetic-flotation process for spodumene, which uses a weak magnetic-strong magnetic-flotation process to separate spodumene. A weak magnetic separation process of 150-175kA / m and a strong magnetic separation process of 770-950kA / m are used to remove some of the iron-containing minerals before flotation. The relative shortcomings of this technology are: a) When the specific magnetic susceptibility / permeability of Fe silicate minerals in the flotation system is very low, the magnetic field strength of strong magnetic separation is not high enough to effectively separate gangue; b) Strong magnetic separation processes with magnetic field strength reaching 770-950 kA / m do not have high separation selectivity and are prone to loss of target minerals in magnetic products, especially when the Fe content in pure spodumene minerals in the ore is high; c) Strong magnetic separation has relatively high processing costs, requires a large amount of water, and the pores of the electro-magnetic medium are prone to clogging, which is relatively complicated to clean and dispose of after clogging; d) Magnetic separation alone cannot obtain concentrate products of the target minerals and needs to be combined with flotation processes, such as the lithium ore beneficiation method disclosed in Chinese patent CN115739380B, which adopts a process of magnetic separation for iron removal, pre-flotation of mica, and re-flotation of spodumene.

[0005] (2) Utilizing the difference in photoelectric properties between amphibole minerals and target minerals, photoelectric pre-selection is used for pre-removal before mineral separation. For example, the spodumene beneficiation process disclosed in Chinese Patent CN113769883B removes some impurities such as amphibole and biotite from the raw ore through photoelectric waste removal, thereby improving the efficiency of subsequent lithium separation. The relative shortcomings of this technology are: a) even after partially removing amphibole and biotite minerals, some waste minerals will still enter the subsequent grinding and flotation system; b) the pre-selection efficiency depends on the intergrowth relationship between minerals, and it is difficult to effectively pre-select and separate ores with fine intergrowth and complex symbiotic relationships; c) the unit processing capacity of photoelectric separation is relatively low, and it needs to be combined with a relatively complex ore crushing-screening-pre-selection process, and it is still mainly used as an auxiliary operation for mineral flotation separation.

[0006] (3) By utilizing the differences in the surface physicochemical properties of amphibole minerals, selective removal of amphibole gangue minerals can be achieved using methods such as preferential flotation or suppression flotation. For example, the beneficiation method for bastnaesite disclosed in Chinese Patent CN110449257B involves adjusting the pH to 8.5-9.5 by adding alkaline substances and then using a water glass-like mineral inhibitor to selectively suppress the flotation of sodium iron amphibole, thereby improving the quality of rare earth concentrates. However, this method is relatively suitable for water glass-like suppression flotation systems, but it is not well-suited for flotation systems where both the target mineral and non-target minerals are silicate minerals. Chinese patent CN105964401B discloses a beneficiation method for high-iron nepheline ore, employing a weak magnetic separation-flotation-strong magnetic separation process. After weak magnetic separation to remove strongly magnetic minerals, a mixed collector of potassium oleate and polyoxyethylene ether is used to preferentially float amphibole, titanosite, biotite, sericite, and amphibole gangue minerals. Strong magnetic separation is then used to remove impurities, resulting in a non-magnetic nepheline concentrate. However, this flotation stage uses a preferential flotation system suitable for mixed flotation of amphibole and pyroxene minerals, without addressing the separation of these two types of minerals. Chinese patent CN107790283B discloses a beneficiation process for amphibole-type primary iron ore, employing a wet pre-magnetic separation-weak magnetic separation-reverse flotation-strong magnetic separation process to obtain high-grade iron concentrate. This process removes most amphibole minerals through flotation but does not address the separation of amphibole and pyroxene minerals. Some technologies employ stepwise and separate flotation for different minerals. Chinese patent CN118268139B discloses a separate and rate-based flotation method for hard rock lithium ore containing multi-phase lithium minerals, which separately floats phosphogypsum and spodumene, etc. However, it cannot effectively solve the problem of controlling the orientation of iron-bearing amphibole minerals.

[0007] Furthermore, gravity separation based on material density has limited effectiveness, mainly due to the fact that the density of gangue-like minerals is similar to that of the target mineral. For example, the relative density of spodumene minerals in a spodumene deposit formed from basic rocks is 3.0-3.2 g / cm³. 3 The relative density of high-speed tremolite is 2.9-3.0 g / cm³. 3 This results in gravity separation having virtually no selectivity in mineral separation.

[0008] In summary, the existing reported techniques for separating amphibole minerals (amphibole, tremolite, ferro-amphibole, glaucophane, etc.) during the beneficiation and processing of oxidized minerals have the following main drawbacks:

[0009] 1) The separation technology based on the magnetic differences of ore minerals and its combined separation technology are limited by the low magnetic permeability of iron-bearing amphibole minerals in the ore. Generally, strong magnetic separation (magnetic field strength ≥960kA / m) is required to separate some of the Fe-bearing gangue minerals. The separation selectivity of strong magnetic separation is not high, while the separation cost is relatively high. Moreover, the loss of the target metal mineral is large when magnetic separation removes amphibole, especially when the target mineral has a high Fe content, such as pure spodumene mineral with high Fe content.

[0010] 2) Pre-selection technology based on the differences in photoelectric properties of ore minerals is mainly limited by the effective separation particle size of photoelectric separation operations. It is suitable for ores with relatively simple inter-mineral structures and coarse-grained liberation. Although it can separate some amphibole group minerals, it has poor adaptability to ores with complex co-occurrence relationships between amphibole and target minerals and fine-grained target minerals. In addition, it requires complex crushing and screening processes and has low single-unit processing capacity.

[0011] 3) Although magnetic separation and photoelectric separation can partially remove amphibole minerals when used alone, they can only be used as auxiliary processes. They still need to be combined with flotation processes to separate the target minerals from non-target minerals. They cannot solve the problem of highly selective enrichment and recovery of target minerals.

[0012] 4) Relatively speaking, existing mineral processing technologies are less efficient at separating and classifying amphibole minerals. Currently, the flotation separation of amphibole minerals mostly employs mixed flotation methods to separate them from non-chain-structured oxide minerals. However, for the flotation separation of amphibole and pyroxene minerals (spodumene, diopside, etc.), which are also chain-structured silicate minerals, there are currently no reports of relatively efficient mineral flotation methods. Summary of the Invention

[0013] According to one embodiment of the present invention, the object is to provide a flotation separation method for iron-bearing amphibole minerals, applicable to flotation separation systems for different target minerals and amphibole group minerals, and particularly to solve the problem of selective flotation separation of lithium-bearing minerals and iron-bearing amphibole minerals in low-grade spodumene ore.

[0014] The above objective can be achieved through the following technical solutions:

[0015] According to one aspect of the present invention, a flotation separation method for iron-bearing amphibole minerals is provided, comprising:

[0016] Step S1: The iron-bearing amphibole mineral ore is crushed and dissociated. During the crushing and dissociation process, a combined modifier is added to obtain slurry A.

[0017] The combined modifier includes a reducing component and a settling component. The reducing component is selected from one or more of hydroxylamine and its salts, sulfites, and nitrites. The settling component is selected from one or more of carbonates and small molecule carboxylate salts with ≤4 C atoms.

[0018] Step S2: The slurry A is prepared and stirred. During the stirring process, a strong electrolyte conditioner is added to obtain slurry B.

[0019] Step S3: Add the first collector to the slurry B to perform flotation separation of the iron-bearing amphibole minerals, and obtain product C containing iron-bearing amphibole minerals and slurry D containing the target mineral.

[0020] Preferably, the amount of the combined modifier is 400-3000 g / t relative to dry ore.

[0021] Preferably, in the combined modifier, the ratio of the reducing component to the sedimentation component is (0.1-20):1.

[0022] Preferably, the strong electrolyte modifier is an electrically neutral strong electrolyte.

[0023] Preferably, the strong electrolyte modifier is selected from one or more of ammonium strong electrolytes, sulfate electrolytes, and nitrate electrolytes.

[0024] Preferably, the strong electrolyte adjuster is one or more of ammonium sulfate, ammonium chloride, sodium sulfate, potassium sulfate, sodium nitrate, and potassium nitrate.

[0025] Preferably, the amount of the strong electrolyte modifier used is 100-1000 g / t relative to dry ore.

[0026] Preferably, the strong electrolyte modifier is selected from reagents that have a synergistic effect with the reducing component in the combined modifier, i.e., the strong electrolyte ion component is similar to the reducing component, or the active components can undergo redox transformation, thereby reducing the number of ion types in the redox process. More preferably, when the reducing component in the combined modifier is hydroxylamine and its salts, the strong electrolyte modifier is an ammonium-based strong electrolyte; when the reducing component in the combined modifier is a sulfite, the strong electrolyte modifier is a sulfate electrolyte; and when the reducing component in the combined modifier is a nitrite, the strong electrolyte modifier is a nitrate electrolyte.

[0027] Preferably, the first collector is an anionic surfactant with ≤12 carbon atoms. Further, the first collector is selected from one or more collectors selected from fatty acids, alkyl sulfonic acids and their salts, and alkyl sulfuric acids and their salts.

[0028] Preferably, the first collector is selected from C 4-10 Saturated fatty acids, carboxylic acids, C 4-10 sulfonic acid and its salts and C 4-10 One or more of sulfuric acid and its salts as collectors.

[0029] More preferably, the first collector includes at least one of the fatty acids.

[0030] Preferably, the amount of the first collector is 50-1000 g / t relative to dry ore.

[0031] Preferably, the flotation separation method for iron-bearing amphibole minerals further includes:

[0032] Step S4: Add a modifier to the slurry D to modify the mineral surface and obtain slurry F;

[0033] Step S5: Add a second collector to the slurry F to perform flotation separation of the target mineral and obtain the target mineral concentrate G.

[0034] Preferably, the second collector is C 12 -C 32 Long-chain anionic surfactants.

[0035] Furthermore, when the target mineral is a pyroxene mineral, the second collector is one or more collectors selected from fatty acid collectors, alkyl sulfonate collectors, and alkyl sulfate collectors.

[0036] More preferably, the second collector includes at least one of fatty acid collectors.

[0037] Preferably, when the target mineral is pyroxene, step S4 includes: first adding a combined etch modifier to perform surface etch modification of the mineral to obtain etch slurry E; then adding a metal ion activator to the etch slurry E for selective activation adjustment to obtain slurry F.

[0038] Preferably, the combined etch modifier is composed of a first type of alkali and a second type of alkali, wherein the first type of alkali is a carbonate and the second type of alkali is selected from strong alkali and / or ammonia water, and the ratio of the first type of alkali to the second type of alkali is (0.1~10):1.

[0039] Preferably, the amount of the combined erosion modifier is 100-5000 g / t based on dry ore.

[0040] Preferably, the amount of the metal ion activator used is 10-500 g / t based on dry ore.

[0041] Preferably, the metal ion activator is one or more of calcium chloride, magnesium chloride, magnesium sulfate, calcium nitrate, and magnesium nitrate.

[0042] Beneficial effects: According to one embodiment of the present invention, by crushing and dissociating the mineral raw material and adding a combination of modifiers for surface modification, and then adding a strong electrolyte modifier for enhanced conductivity of the mineral surface layer, a collector is added to preferentially float iron-bearing amphibole minerals, thereby achieving highly selective separation of iron-bearing amphibole minerals from the target minerals and reducing the negative impact of iron-bearing gangue minerals on mineral separation.

[0043] Compared with the prior art, some embodiments of the present invention also have the following advantages:

[0044] 1) A new mineral interface control technology is used to modify the expression of surface properties of iron-bearing amphibole minerals. The core is based on the application of a reagent adjustment system to form a dense Fe-OH surface layer on the surface of these minerals and enhance their conductivity, thereby effectively improving the feasibility of preferentially floating iron-bearing amphibole minerals.

[0045] 2) The collector for preferential flotation of iron-bearing amphibole minerals, namely the first collector, adopts short-chain / medium-chain anionic surfactants. By utilizing the weak adsorption and foaming properties of this type of agent, the selectivity of the collector is improved, thereby enhancing the selectivity of separating iron-bearing amphibole minerals from other minerals.

[0046] 3) After removing iron-bearing amphibole minerals first by flotation, the surface of the target mineral is modified and reconstructed. A similar long-chain anionic surfactant is used as a second collector for the flotation of the target mineral, thus achieving the synergistic effect of front-end and back-end flotation collectors.

[0047] 4) The preferential flotation separation process effectively removes iron-bearing amphibole minerals, greatly reducing the negative impact of iron-bearing gangue minerals on mineral separation. After flotation separation, the selective separation efficiency of minerals is improved, which is conducive to improving the efficiency of the separation system and reducing production and processing costs. It is especially suitable for mineral systems with complex mineral particle sizes.

[0048] 5) The flotation separation efficiency of iron-bearing amphibole minerals is high, which enhances the overall synergistic coupling effect of selective collectors and modifiers, and is more conducive to improving the inter-reagent interaction efficiency, reducing reagent dosage, improving the selectivity of mineral separation, and at the same time, it is conducive to obtaining high-quality and high-recovery target concentrate products, and enhancing the efficiency of complex resource processing and utilization.

[0049] 6) Iron-bearing amphibole minerals can be effectively separated using only flotation separation technology. The separation process is simple, which improves the applicability of the process and avoids the matching problem between flotation and combined processes such as photoelectric separation, magnetic separation, and gravity separation in ore processing. Attached Figure Description

[0050] Figure 1 This is a schematic diagram of the flotation principle process for separating iron-bearing amphibole minerals and classifying target minerals in one embodiment of the present invention. Detailed Implementation

[0051] The technical solution of the present invention will be clearly and completely described below with reference to embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0052] Amphibole minerals are a common type of gangue mineral, and they are difficult to selectively separate during the beneficiation and processing of some silicate oxide ores. For example, pegmatite-type spodumene deposits often contain metamorphic gabbro minerals, such as amphibole and tremolite, which are mostly Fe. These minerals have similar crystal structures to spodumene and belong to the chain silicate group, making their separation from spodumene by flotation extremely difficult. As described above, both methods utilizing the weak magnetic properties of Fe-containing amphibole minerals for magnetic separation and methods utilizing differences in photoelectric properties of these minerals have some drawbacks.

[0053] The present invention aims to provide a flotation separation method for iron-bearing amphibole minerals. This method utilizes flotation separation technology to achieve highly selective separation of high-iron-bearing amphibole minerals such as amphibole, tremolite, sodium amphibole, actinolite, and glaucophane from target silicate minerals such as spodumene, wollastonite, and diopside. This improves the selectivity and applicability of the mineral separation system. It is particularly suitable for ore mineral systems where iron-bearing amphibole minerals can have a significant negative impact on the flotation separation of other minerals. For example, it is applicable to the flotation separation system of low-grade spodumene ore with a high proportion of iron-bearing amphibole minerals and a complex mineral composition, which is difficult to separate.

[0054] The flotation principle and process adopted in the flotation separation method provided by this invention are as follows: Figure 1 As shown, the process involves pre-floting iron-bearing gangue minerals followed by slurry adjustment and target mineral recovery. This involves preferentially flotating iron-bearing amphibole minerals and then recovering the target minerals through flotation. The main approach utilizes the differences in electrical conductivity expressed by hydroxylated or modified active sites on the surfaces of different minerals to regulate the expression activity of iron active sites on the surface of amphibole minerals and Al / Ca / Mg active adsorption sites on the surface of the target minerals. Iron-bearing amphibole minerals are preferentially pre-flotted using Fe collectors, and then the slurry after flotation of iron-bearing amphibole minerals is adjusted and the target minerals are recovered through flotation.

[0055] The technical basis of the flotation separation method provided in this application mainly includes: a) During the liberation of ore minerals, single-chain spodumene minerals easily expose Li-O bonds and some Al-O and Si-O bonds, while double-chain iron-bearing amphibole minerals easily expose Na in the gaps between the double chains during fragmentation and liberation. + Li + K + Ca 2+ Fe 2+ and some small-radius cations Mg 2+ Fe 2+ Mn 2+ Al 3+ Fe 3+ Compared to single-chain pyroxene minerals, double-chain amphibole minerals have a relatively larger number of exposed cations on their surface, thus exhibiting a stronger positive charge electrostatic attraction. b) During mineral dissociation, due to the easy solubility of some metal cations in water and their hydration bonding with a large number of hydroxyl groups, different hydroxylation layers of different metal ions are formed on the surface of different minerals, such as the formation of phase-like colloidal layers of Fe(OH)2, Fe(OH)3, Mg(OH)2, Ca(OH)2, and Al(OH)3. These homogeneous surface layers, due to differences in ionic bonding states and structures, lead to variations in surface conductivity or electrostatic adsorption. There are significant differences in reactivity. Relatively speaking, Fe-OH colloids have stronger conductivity, while Al / Mg / Ca-OH interfaces have higher resistance. Hydroxylated silanols (Si-OH) have the highest surface resistance. Furthermore, these differences in the charge properties of the interfaces can be further increased by modifying the mineral surface. c) Small molecule anionic surfactants that rely on electrostatic adsorption for collection often exhibit selective adsorption tendencies on mineral surfaces with stronger positive charge expression. This makes amphibole minerals with strong Fe-OH colloid expression more easily collected than Al-OH pyroxene minerals.

[0056] In one embodiment of the present invention, the flotation separation method for iron-bearing amphibole minerals mainly includes the following steps:

[0057] Step S1: Mineral crushing and dissociation and surface modification. This includes crushing and dissociating the iron-bearing amphibole mineral ore, adding a combined modifier during the crushing and dissociation process to modify the mineral surface, and obtaining crushed and modified slurry A after this step.

[0058] One of the main purposes of this step is to liberate the target mineral and gangue minerals, providing a suitable separation particle size for mineral flotation separation. The target mineral and gangue minerals are physically separated by mechanical crushing. Wet grinding is performed with clean water or recycled water to adjust the grinding mass concentration to 45% to 75%, and the grinding fineness is selected to be -0.074 mm, accounting for 40% to 95%.

[0059] During the process, without the use of modifiers, the minerals are pulverized from large to small particle sizes, resulting in the formation of highly reactive mineral surfaces. Some of the exposed, easily soluble ionic components dissolve into the aqueous phase, while some relatively water-insoluble positively charged / positively ionized surface active sites (such as Fe) are released. 3+ Fe 2+ Ca 2+ Mg 2+ Al 3+ S i4+ Mn 2+ (e.g., hydroxylation of free -OH groups in aqueous solutions due to electrostatic attraction) form a metal-hydroxylated (Me-OH) active surface layer, exhibiting a structure similar to a hydroxide colloidal layer. Different metal ions exhibit different conductivity in their hydroxylated active layers. Oxides or hydroxides of transition metals (Fe / Mn-OH) often exhibit semiconductor properties, resulting in higher conductivity than Al-OH, Mg / Ca-OH, and Si-OH surfaces. Therefore, in mineral interface states without the addition of combined modifiers, the Fe-OH active sites in iron-bearing amphibole minerals, due to electrostatic forces, have a relatively stronger ability to compete for anion collectors compared to pyroxene, feldspar, quartz, and mica minerals.

[0060] On the other hand, due to the unavoidable presence of Fe in the grinding solution medium and its mineral flotation system... 2+ Fe 3+ Mg 2+ Ca 2 + Al 3+ Plasma, these ions, can also easily adsorb onto newly formed mineral surfaces, affecting the properties expressed by different mineral surfaces, such as iron-containing species (Fe) dissolved from a worn steel ball during mineral dissociation. 2+ Fe 3+ (e.g., Ca), adsorbed onto mineral surfaces, causes homogenization of surface charge expression, thereby increasing the difficulty of selective mineral separation. Furthermore, the unavoidable presence of Ca in the solution medium... 2+ Mg 2+ After ions adsorb minerals, they can also cause the homogenization of the expression of mineral surface properties.

[0061] Furthermore, regarding the hydroxylated colloidal structure (Me-OH structure) or polyhydroxyl Me(OH)2 surface layer of minerals, in neutral or weakly alkaline flotation systems, the Fe(OH)2 colloid on the mineral surface exhibits the best conductivity, followed by Fe(OH)3, while Mg(OH)2 and Ca(OH)2 have weaker conductivity, and Al(OH)3 and Si-OH have the weakest conductivity. From the perspective of electrostatic trend expression, the application of collectors based on electrostatic adsorption preferentially adsorbs iron-containing amphibole silicate minerals with selectivity.

[0062] Therefore, in order to achieve the purpose of the present invention of highly selectively and preferentially floating iron-bearing amphibole minerals, the present invention adds a modifier during the mineral dissociation process to increase the difference in charge property expression between Fe-OH hydroxylated surfaces and other Me-OH surfaces, while adjusting the migration and orientation of inevitable ions in the solution medium. In particular, on the surface of iron-bearing amphibole minerals, a surface layer with high Fe(OH)2 conductivity is obtained through modification.

[0063] In a preferred embodiment of the present invention, the modifying agent in this step is a combined modifying agent, comprising a reducing component and a settling component. Further, the modifying agent is a combined modifying agent formed by combining the reducing component and the settling component in a ratio of (0.1–20):1.

[0064] More preferably, the dosage of the combined modifier is 400-3000 g / t relative to dry ore, which can achieve a better modification effect.

[0065] The reducing component is a water-soluble reducing agent that can compete for or consume free electrons in the system, thus controlling oxygen consumption within the system. On one hand, it can slow down the depletion of low-valence Fe and Fe2+ in iron-containing amphibole. 2+ Oxidized to a high-valence state of Fe 3+ This trend strengthens the formation of Fe-OH and Fe(OH)2, while on the other hand, it redox free OH... - This facilitates the stable formation of Fe-OH. The reducing component is selected from one or more of hydroxylamine and its salts, sulfites, and nitrites. Specifically, hydroxylamine and its salts, such as hydroxylamine, hydroxylamine hydrochloride, hydroxylamine sulfate, hydroxylamine nitrate, isopropyl alcoholamine, ethanolamine, O-benzylhydroxylamine, and O-allelic hydroxylamine, mainly react in the following way: NH₂OH + 2H₂O + 2e⁻ = NH₄OH + 2OH⁻. - Sulfites, such as sodium sulfite, sodium bisulfite, and sodium dithionite, mainly react to form SO3. 2- +3H₂O + 6e = S 2- +6OH - Nitrites, such as sodium nitrite, potassium nitrite, and nitrosamines, mainly react to form NO2. - +H₂O + 2e = NO₃ - +2OH - .

[0066] The sedimentation component primarily functions to regulate the sedimentation of unavoidable metal ions in the solution medium within the mineral grinding and dissociation system, as well as to hydrophilically modify the surfaces of different minerals. Further, the sedimentation component is selected from one or more carbonates and small-molecule (C atom number ≤ 4) carboxylates, specifically, for example, sodium carbonate, sodium bicarbonate, ammonium carbonate, formic acid, acetic acid, oxalic acid, succinic acid, etc.

[0067] Step S2: Conductivity enhancement modification of the mineral surface layer. This includes: conditioning the slurry A obtained in step S1 by adding a strong electrolyte conditioner during stirring, and then slurry B after stirring and conditioning.

[0068] Furthermore, during slurry preparation, the slurry concentration is adjusted to 25%–45%. During stirring, 100–1000 g / t (relative to dry ore) of a strong electrolyte modifier that enhances interfacial conductivity is added to strengthen surface layer conductivity and further enhance the differences in surface Me-OH conductivity and electrostatic adsorption between different minerals. The stirring and slurry preparation time is 2–6 minutes to obtain a better conductivity enhancement modification effect.

[0069] Preferably, the strong electrolyte adjuster is an electrically neutral strong electrolyte; selected from one or more of ammonium-based strong electrolytes, sulfate-based electrolytes, and nitrate-based electrolytes. More specifically, it may employ one or more of ammonium sulfate, ammonium chloride, sodium sulfate, potassium sulfate, sodium nitrate, and potassium nitrate.

[0070] More preferably, the selection of the strong electrolyte modifier is preferentially coordinated with the reducing component selected in step S1 of the combined modifying modifier. Specifically, hydroxylamine-based reducing modifiers are preferred, especially ammonium-based strong electrolytes; sulfite-based reducing components are preferred, especially sulfate-based electrolytes; and nitrite-based reducing components are preferred, especially nitrate-based electrolytes. In these preferred embodiments, the reducing components are similar to the ionic components of the strong electrolyte, or the active components can undergo redox transformations, resulting in a relatively smaller number of ion types in the redox process.

[0071] By adjusting the reagent system and regulating the mineral interface, specifically by adding a combination of modifiers, the surface properties of iron-bearing amphibole minerals are modified, resulting in the formation of a dense Fe-OH surface layer. Furthermore, a strong electrolyte modifier is added to enhance the conductivity, thereby effectively improving the feasibility of preferentially flocculating iron-bearing amphibole minerals.

[0072] Step S3: Preferential flotation separation of iron-bearing amphibole. This includes: adding a first collector to the slurry B obtained in step S2, performing flotation separation of iron-bearing amphibole minerals, and obtaining product C of iron-bearing amphibole minerals and slurry D containing the target mineral after the removal of iron-bearing amphibole minerals.

[0073] Furthermore, a froth flotation separation process is employed. Specifically, after adding the first collector, the mixture is stirred and adsorbed for 2–6 minutes. Subsequently, air is introduced to generate foam, and the collection and mineralization-foaming flotation separation of iron-bearing amphibole is carried out. This allows the iron-bearing amphibole minerals to enter the froth layer, while the target mineral remains in the flotation cell (and can be separated from the bottom of the cell), thereby achieving preferential flotation separation of iron-bearing amphibole.

[0074] The foam separation time is 2–10 min; the preferential flotation time for iron-bearing amphibole minerals is 2–10 min; iron-bearing amphibole minerals are separated by one or two roughing processes to obtain foam product C and pulp D; the obtained foam product C is mainly iron-bearing amphibole minerals removed by flotation, and the obtained pulp D is a mixed pulp containing the target mineral and other gangue minerals after the removal of iron-bearing amphibole group minerals.

[0075] More preferably, the amount of the first collector, i.e. the collector for preferential flotation of iron-containing amphibole, is 50-1000 g / t relative to dry ore, which can achieve a better collecting effect.

[0076] In the process of flotation of iron-bearing amphibole minerals, the first collector used is a highly selective collector, which is a short-chain / medium-chain organic anionic surfactant. The weak adsorption and foaming properties of this type of agent are used to improve the selectivity of the collector, thereby enhancing the selectivity of separating iron-bearing amphibole minerals from other minerals.

[0077] Preferably, the first collector is a short-chain / medium-chain fatty acid R-COO. - Alkyl sulfonic acid R-SO3 - and its salts, alkyl sulfuric acid R-SO4 - And one or more of its salt collectors. Further, the number of C atoms in the collector is ≤12. More preferably, the first collector is selected from C 4-10 Saturated fatty acids, carboxylic acids, C 4-10 sulfonic acid and its salts, C 4-10 One or more of sulfuric acid and its salts as collectors; wherein, C 4-10 Saturated fatty carboxylic acids, such as butyric acid (C4), isobutyric acid (C4), valeric acid (C5), 2-methylbutyric acid, isovaleric acid, caprylic acid (C8), and capric acid (C8). 10 C. 4-10 Sulfonic acids / sulfuric acids and their salts, such as butylsulfonic acid, benzenesulfonic acid, sodium pentanesulfonate, sodium 1-decanesulfonate, sodium 1-pentylsulfonate, sodium n-decylsulfonate, etc.

[0078] Under the premise of modifying the mineral surface properties in steps S1 and S2, the above-mentioned short-chain / medium-chain organic surfactants are used for the collection and flotation of iron-bearing amphibole minerals. Their function is twofold: Firstly, due to the difference in electrostatic attraction, the active groups of the short-chain / medium-chain collectors preferentially adsorb onto the surface of iron-bearing amphibole minerals containing a dense and stable Fe-OH surface layer, while the collectors are not adsorbed onto the relatively weak electrostatically charged Ca-OH, Mg-OH, Al-OH, or non-conductive Si-OH surfaces, thereby achieving selective mineralization between different minerals. Secondly, the short-chain / medium-chain fatty acid collectors, upon contact with metal ions (Ca... 2+ Mg2+ Fe 3+ The adsorption and activation of mineral surfaces by the first collector (e.g., the adsorption is mostly physical, and the ability to adhere to bubbles is relatively weak, making it easy to desorb after stirring) is also relatively weak. Under the relatively loose adsorption state of short-chain / medium-chain surface-active groups, it is difficult to form a stable mineral-reagent-foam three-phase foam, further avoiding the negative effects of metal ion adsorption and improving the relative selectivity of preferential mineral flotation. In some preferred embodiments, the first collector includes at least one of the fatty acid collectors.

[0079] In addition, in some optional embodiments, when iron-bearing amphibole minerals are preferentially floated, a small amount of frother can be added when the froth state is poor. One of the small molecule alcohol frothers such as MIBC, octyl alcohol, and hexanol can be used. The amount of frother used is 0 to 40 g / t relative to the dry ore feed.

[0080] In addition, in some optional embodiments, before step S3 of separating iron-bearing amphibole minerals, a physical desliming method can be used to remove some fine-grained mud minerals. The purpose is to reduce the impact of fine-grained minerals on subsequent flotation operations and to reduce the amount of reagents used in the flotation process. Physical desliming methods may include hydrocyclone desliming, settling desliming, gravity desliming, etc.

[0081] Through steps S1 to S3 described above, highly selective separation of iron-bearing amphibole minerals from the target mineral is achieved. (Reference) Figure 1 As shown, in some embodiments, based on the slurry D containing the target mineral obtained after removing iron-bearing amphibole minerals, a modifier is first added to modify and remodel the slurry surface, and then a flotation collector for the target mineral is added to enrich it through flotation, thereby obtaining the target mineral concentrate and separation tailings. The obtained target mineral concentrate has a high grade, high recovery rate, and low total iron content.

[0082] In some embodiments of the present invention, after steps S1-S3, the following steps are further included:

[0083] Step S4: Mineral surface dissolution, modification, and reconstruction. This includes sequentially adding the modifier required for the flotation of the target mineral to the slurry D obtained in step S3 to modify the surface of the target mineral.

[0084] When the recovered mineral is spodumene, the purpose of this process is to selectively dissolve the spodumene surface while selectively activating it with specific metal ions, thereby separating and enriching spodumene from gangue minerals such as feldspar, mica, and quartz. Preferably, the process includes the following steps:

[0085] Step S41: First, add 100-5000 g / t of the combined erosion modifier (based on dry ore), stir and adjust the slurry for 5-20 minutes to obtain the erosion-modified slurry E. The combined erosion modifier is an alkaline combined reagent, including a first type of alkali and a second type of alkali. The first type of alkali is a carbonate, selected from one or more of sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, ammonium carbonate, and ammonium bicarbonate. The second type of alkali has hydroxide ions as anion, selected from strong bases such as sodium hydroxide, potassium hydroxide, and one or more of ammonia water. Using this combined erosion modifier, a high concentration of OH- is produced through the second type of alkali. - The process involves scrubbing and dissolving the mineral surface, using a first-type alkali containing carbonate ions to adjust the solution medium and prevent the formation of metal ions, thereby modifying the mineral surface and dispersing the slurry. Furthermore, the relative ratio of the first-type alkali to the second-type alkali is (0.1–10):1 to achieve a better dissolution and modification effect.

[0086] Step S42: Subsequently, 10–500 g / t of metal ion activator (based on dry ore) is added to the modified dissolving slurry E, and selective activation is performed for 2–6 minutes to obtain activated slurry F. The metal ion activator is one or more of calcium chloride, magnesium chloride, magnesium sulfate, calcium nitrate, and magnesium nitrate.

[0087] Step S5: Flotation enrichment and recovery of pyroxene minerals (target minerals). This includes adding the collector required for adsorption and mineralization of the target mineral, i.e., the second collector, to the slurry F obtained in step S4, and performing flotation separation on the target minerals to obtain the target mineral concentrate G.

[0088] In this step, the second collector used is a long-chain anionic collector, namely C... 12 -C 32 The second collector is a long-chain anionic surfactant. Preferably, the second collector is an anionic surfactant of the same type as the first collector. By using a long-chain anionic surfactant of the same type as the first collector for the flotation of the target mineral, the advantages of the front-end and back-end flotation collectors are synergistically achieved, improving the interaction efficiency between the reagents, enhancing the selectivity of collection and adsorption, and reducing the amount of reagent used. In some preferred embodiments, the second collector also includes at least one of the fatty acid collectors.

[0089] Furthermore, in this step, the amount of collector used, relative to the feed, is 100–4000 g / t. Even further, 2–10 minutes of mineralization conditioning and 3–30 minutes of aerated flotation are performed, allowing the target mineral to enter the froth product while other gangue minerals remain at the bottom of the tank, thereby achieving flotation separation of different minerals to obtain mineral concentrate G and flotation tailings H.

[0090] When the recovered mineral is spodumene, the long-chain anionic collector is selected from C 12 -C 32 The surfactant comprises one or more of fatty acid surfactants, alkyl sulfonic acid surfactants (R-SO3-Me), and alkyl sulfate surfactants (R-OSO3-Me). The fatty acids include oleic acid, sodium oleate, linoleic acid, oxidized paraffin soap, naphthenic acid soap, lauric acid, and talc oil. The alkyl sulfonic acids include sodium secondary alkyl sulfonate, sodium diisopropylnaphthalene sulfonate, sodium dibutylnaphthalene sulfonate, sodium dodecyl sulfonate, and sodium dodecylbenzene sulfonate. The alkyl sulfates include sodium dodecyl sulfate, ammonium dodecyl sulfate, magnesium lauryl sulfate, sodium cocoyl sulfate, and triethanolamine dodecyl sulfate.

[0091] Furthermore, for the target mineral concentrate product G obtained by flotation separation, this invention is applicable to various aerated flotation processes, including aerated flotation using a multi-stage flotation method, including at least one roughing, one scavenging and one cleaning stage, and flotation separation processes using middlings sequential return process, rapid flotation-middlings regrinding and other separation processes.

[0092] The implementation methods of this application will be illustrated below with specific examples.

[0093] Example 1

[0094] This is a low-grade lithium ore with high Fe content in amphibole gangue minerals. It is an acidic lithium ore with a Li₂O content of 0.8% and a TFe content of 1.9%. 85% of the iron mineral phase is amphibole, accounting for 12%–15% of the ore's total mineral composition. Other minor components include magnetite, hematite, limonite, and ilmenite, as well as trace amounts of tantalite and columbite. The abundant presence of amphibole minerals makes the enrichment, separation, and beneficiation of spodumene minerals difficult, resulting in both a low Li₂O recovery rate and difficulty in obtaining high-grade lithium concentrate.

[0095] The method of the present invention for processing the ore specifically includes the following steps:

[0096] Step 1): Mineral crushing and dissociation and surface modification: After slurry preparation, the ore is ground to a particle size of -0.074mm, accounting for 60%. During the grinding process, 300g / t sodium nitrite + 400g / t sodium bicarbonate modifiers are added to modify the surface charge properties and their strength of different minerals. The grinding yields crushed and modified slurry A with a mass concentration of 65%.

[0097] Step 2): Mineral surface layer conductivity enhancement modification: The concentration of slurry A is adjusted to 35% by using recycled water, and 200g / t of strong electrolyte modifier, namely sodium nitrate, is added to enhance the interfacial conductivity. After stirring and adjusting the slurry for 3 minutes, slurry B is obtained.

[0098] Step 3): Preferential flotation separation of iron-bearing amphibole: 300 g / t of a first collector, using a combination collector of sodium 1-decane sulfonate, isovaleric acid, and octanoic acid in a 1:1:1 ratio, is added to slurry B. A single aerated flotation is then performed for 6 minutes, yielding flotation froth product C and bottom product D. In froth product C, the TFe content is 10.2%, the Li₂O content is 0.12%, the Fe recovery rate relative to the feed is 89%, and the Li₂O loss rate is 3.2%.

[0099] Step 4): Mineral surface dissolution modification and reconstruction: Add a combination of 500g / t sodium carbonate and 200g / t sodium hydroxide as a dissolution modifier to the bottom product D of the tank, stir and adjust the slurry for 5 minutes, then add 100g / t calcium chloride to activate and adjust the slurry for 3 minutes to obtain mineral surface dissolution and reconstruction slurry F.

[0100] Step 5): Flotation enrichment and recovery of pyroxene minerals (target minerals): A combination of 200 g / t oxidized paraffin soap (731) and 100 g / t oleic acid was added to the slurry F as a second collector. Subsequently, aeration was performed for the separation and flotation of spodumene minerals through a roughing, scavenging, and cleaning process, yielding flotation lithium concentrate G and tailings H. The lithium concentrate product G contained 6.1% Li₂O, with a Li₂O recovery rate of 86% relative to the original ore, and a TFe content of 0.2%.

[0101] Compared with existing technologies, the advantages of using the above-described method of this invention to process the mine are as follows:

[0102] a) Compared with the “spodumene flotation-magnetic separation / iron removal magnetic separation-flotation separation process”, the lithium concentrate obtained by using the present invention has a 2.0 percentage point higher Li2O grade, a 15 percentage point higher recovery rate, and a 0.4 percentage point lower Fe content.

[0103] b) Compared with the “photoelectric pre-tailing-flotation-magnetic separation process”, the lithium concentrate obtained by using the present invention has a 1.5 percentage point higher Li2O grade, a 10 percentage point higher recovery rate, and a 0.2 percentage point lower Fe content.

[0104] Example 2

[0105] A low-grade lithium ore with high Fe-containing metamorphic tremolite gangue minerals is a basic rock-originating lithium ore. The raw ore contains 1.2% Li₂O and 2.3% TFe. 78% of the iron mineral phase is altered tremolite, with tremolite accounting for 23%–27% of the total mineral composition. Other minor components include magnetite, ilmenite, pyrite, and trace amounts of tantalite and columbite. The abundant presence of tremolite gangue minerals severely hinders the recovery of this ore.

[0106] The method of the present invention for processing the ore specifically includes the following steps:

[0107] Step 1): Mineral crushing and dissociation and surface modification: After slurry preparation, the ore is ground to a particle size of -0.074mm, accounting for 65%. During the grinding process, a modifier consisting of 200g / t hydroxylamine sulfate and 100g / t oxalic acid is added to modify the surface charge properties and their strength of different minerals. The grinding process yields a crushed and modified slurry A with a mass concentration of 66%.

[0108] Step 2): Mineral surface layer conductivity enhancement modification: The mineral slurry concentration of slurry A is adjusted to 33% by using recycled water, and 200g / t of potassium sulfate, a strong electrolyte modifier to enhance the interfacial conductivity, is added. After stirring and adjusting the slurry for 2 minutes, mineral slurry B is obtained.

[0109] Step 3): Preferential flotation separation of iron-bearing amphibole: 600 g / t of a first collector, using a butyric acid: octanoic acid: capric acid ratio of 1:1:1, is added to slurry B. A single aerated flotation is then performed for 4 minutes, yielding flotation froth product C and bottom product D. In froth product C, the TFe content is 8.5%, the Li₂O content is 0.09%, the Fe recovery rate relative to the feed is 93%, and the Li₂O loss rate is 3.1%.

[0110] Step 4): Mineral surface dissolution modification and reconstruction: Add a combination of sodium bicarbonate and sodium hydroxide (800 g / t) to the bottom product D of the tank, stir and adjust the slurry for 10 min, then add magnesium chloride (100 g / t) to activate and adjust the slurry for 2 min to obtain mineral surface dissolution and reconstruction slurry F.

[0111] Step 5): Flotation enrichment and recovery of pyroxene minerals (target minerals): A combined collector of 300 g / t sodium oleate and 100 g / t sodium dodecyl sulfate is added to the slurry F as a second collector. Subsequently, aeration is performed for the separation and flotation of spodumene minerals through a roughing, scavenging, and cleaning process, yielding flotation lithium concentrate G and tailings H. The lithium concentrate product G has a Li₂O content of 6.3%, a Li₂O recovery rate of 92% relative to the original ore, and a TFe content of 0.3%.

[0112] Compared with existing technologies, the advantages of using the above-described method of this invention to process the mine are as follows:

[0113] a) Compared with the “spodumene flotation-magnetic separation / iron removal magnetic separation-flotation / gravity separation-flotation-magnetic separation process”, the lithium concentrate obtained by using the present invention has a 1.7 percentage point higher Li2O grade, a 10 percentage point higher recovery rate, and a 0.3 percentage point lower Fe content.

[0114] b) Compared with the “photoelectric pre-tailing-flotation-magnetic separation / photoelectric separation-magnetic separation-flotation / photoelectric separation-heavy medium-flotation-magnetic separation process”, the lithium concentrate obtained by using the present invention has a 1.3 percentage point higher Li2O grade, an 8 percentage point higher recovery rate, and a 0.3 percentage point lower Fe content.

[0115] The description of this invention is given for illustrative and descriptive purposes only and is not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described in order to better illustrate the principles and practical application of the invention and to enable those skilled in the art to understand the invention and to design various embodiments with various modifications suitable for a particular purpose.

Claims

1. A flotation separation method for iron-bearing amphibole minerals, characterized in that, include: Step S1: The iron-bearing amphibole mineral ore is crushed and dissociated. During the crushing and dissociation process, a combined modifier is added to obtain slurry A. The combined modifier includes a reducing component and a settling component. The reducing component is selected from one or more of hydroxylamine and its salts, sulfites, and nitrites. The settling component is selected from one or more of carbonates and small molecule carboxylate salts with ≤4 C atoms. Step S2: The slurry A is prepared and stirred. During the stirring process, a strong electrolyte conditioner is added to obtain slurry B. Step S3: Add the first collector to the slurry B to perform flotation separation of the iron-bearing amphibole minerals, and obtain product C containing iron-bearing amphibole minerals and slurry D containing the target mineral.

2. The flotation separation method for iron-bearing amphibole minerals according to claim 1, characterized in that, In step S1, the amount of the combined modifier is 400-3000 g / t relative to dry ore. And / or, the ratio of the reducing component to the settling component in the combined modifier is (0.1-20):

1.

3. The flotation separation method for iron-bearing amphibole minerals according to claim 1, characterized in that, In step S2, the strong electrolyte adjuster is an electrically neutral strong electrolyte, selected from one or more of ammonium strong electrolytes, sulfate electrolytes, and nitrate electrolytes; And / or, the amount of the strong electrolyte modifier used is 100 to 1000 g / t relative to dry ore.

4. The flotation separation method for iron-bearing amphibole minerals according to claim 3, characterized in that, When the reducing component in the combined modifier is hydroxylamine and its salts, the strong electrolyte modifier is selected as an ammonium strong electrolyte; when the reducing component in the combined modifier is a sulfite, the strong electrolyte modifier is selected as a sulfate electrolyte; when the reducing component in the combined modifier is a nitrite, the strong electrolyte modifier is selected as a nitrate electrolyte.

5. The flotation separation method for iron-bearing amphibole minerals according to claim 3, characterized in that, The strong electrolyte adjuster is one or more of ammonium sulfate, ammonium chloride, sodium sulfate, potassium sulfate, sodium nitrate, and potassium nitrate.

6. The flotation separation method for iron-bearing amphibole minerals according to claim 1, characterized in that, In step S3, the first collector is an anionic surfactant with ≤12 C atoms, selected from one or more of fatty acids, alkyl sulfonic acids and their salts, alkyl sulfuric acids and their salts; And / or, the amount of the first collector used is 50 to 1000 g / t relative to dry ore.

7. The flotation separation method for iron-bearing amphibole minerals according to claim 6, characterized in that, The first collector is selected from C 4-10 Saturated fatty acids, carboxylic acids, C 4-10 sulfonic acid and its salts and C 4-10 One or more of sulfuric acid and its salts as collectors.

8. The flotation separation method for iron-bearing amphibole minerals according to claim 1, characterized in that, Also includes: Step S4: Add a modifier to the slurry D to modify the mineral surface and obtain slurry F; Step S5: Add a second collector to the slurry F to perform flotation separation of the target mineral and obtain the target mineral concentrate G; The second collector uses C 12 -C 32 Long-chain anionic surfactants.

9. The flotation separation method for iron-bearing amphibole minerals according to claim 8, characterized in that, When the target mineral is pyroxene, the second collector is one or more collectors selected from fatty acids, alkyl sulfonates and alkyl sulfates.

10. The flotation separation method for iron-bearing amphibole minerals according to claim 8, characterized in that, When the target mineral is pyroxene, step S4 includes: first adding a combined etch modifier to perform surface etch modification of the mineral to obtain etch slurry E; then adding a metal ion activator to the etch slurry E for selective activation adjustment to obtain slurry F. The combined etching modifier is composed of a first type of alkali and a second type of alkali. The first type of alkali is a carbonate, and the second type of alkali is selected from strong alkali and / or ammonia. The ratio of the first type of alkali to the second type of alkali is (0.1-10):

1.

11. The flotation separation method for iron-bearing amphibole minerals according to claim 10, characterized in that, The dosage of the combined erosion modifier, calculated based on dry ore, is 100–5000 g / t; The amount of the metal ion activator used, calculated based on dry ore, is 10-500 g / t; The metal ion activator is one or more of calcium chloride, magnesium chloride, magnesium sulfate, calcium nitrate, and magnesium nitrate.

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