A cascade flotation recovery method for iron tailings

Abstract

This invention discloses a cascade flotation recovery method for iron tailings, belonging to the field of mineral processing and solid waste resource utilization technology. It solves at least one problem in existing technologies: insufficient liberation of iron minerals, mica, feldspar, and quartz; difficulty in physical separation; and difficulty in separating silicate minerals. The method includes magnetic separation of the iron tailings slurry; adding a mica modifier and a mica collector to the non-magnetic product for a first roughing, a first scavenging, and a third cleaning; adding sulfuric acid to the mica flotation tailings to adjust the pH to acidic and adding a feldspar activator and a cationic collector for a first roughing, two scavenging, and a third cleaning; adding sodium hydroxide to the quartz concentrate to adjust the pH to neutral conditions and adding a quartz modifier, a quartz collector, and a composite frother for a first roughing, a first scavenging, and two cleaning; and leaching the quartz concentrate with a choline-based ionic liquid. This invention can be used for the cascade flotation recovery of iron tailings.

Description

Technical Field

[0001] This invention belongs to the field of mineral processing and solid waste resource utilization technology, specifically relating to a cascade flotation recovery method for iron tailings. Background Technology

[0002] Iron tailings are the main solid waste generated after iron ore beneficiation. Besides recoverable residual iron minerals, iron tailings typically contain large amounts of silicate minerals such as quartz, feldspar (potassium feldspar and sodium feldspar), and mica. These non-metallic minerals have wide applications in ceramics, glass, coatings, and fillers. Achieving comprehensive recovery of iron minerals, mica, feldspar, and quartz from iron tailings is of great significance for improving resource utilization, reducing environmental pollution, and creating economic benefits.

[0003] However, achieving efficient multi-component separation from iron tailings faces numerous technical challenges: On the one hand, iron tailings have a complex mineral composition and fine particle size. After grinding and beneficiation, the mineral particle size of -0.074mm accounts for more than 50% of the iron tailings, and they contain a large amount of sludge. Iron minerals, mica, feldspar, quartz and other minerals are inter-embedded and wrapped, and the dissociation is insufficient, making physical separation difficult.

[0004] On the other hand, silicate minerals are difficult to separate: mica, feldspar, and quartz are all silicate minerals with similar surface chemical properties and similar floatability in conventional flotation systems. In particular, traditional separation processes are inefficient in iron tailings systems with severe mud formation. Summary of the Invention

[0005] In view of the above analysis, the present invention provides a step-flotation recovery method for iron tailings, which aims to solve at least one of the problems in the prior art, namely, insufficient liberation of iron minerals, mica, feldspar and quartz, difficulty in physical separation, and difficulty in separation of silicate minerals in iron tailings.

[0006] The objective of this invention is mainly achieved through the following technical solutions: This invention provides a method for the cascade flotation recovery of iron tailings, comprising the following steps: Step 1: Perform magnetic separation on the iron tailings slurry to obtain iron concentrate and non-magnetic products; Step 2: After adding mica modifier and mica collector to the non-magnetic product, a primary slurry is obtained. The primary slurry is subjected to one roughing, one scavenging and three cleaning processes to obtain mica concentrate and mica flotation tailings. Step 3: After adding sulfuric acid to the mica flotation tailings to adjust the pH to an acidic environment, feldspar activator and cationic collector are added in sequence to obtain a secondary slurry. The secondary slurry is subjected to one roughing, two scavenging and three cleaning processes to obtain feldspar concentrate and quartz rough concentrate. Step 4: Add sodium hydroxide to the quartz rough concentrate to adjust the pH of the slurry to neutral conditions, add quartz adjuster, quartz collector and compound frother to obtain a three-stage slurry, and perform one roughing, one scavenging and two cleaning processes on the three-stage slurry to obtain quartz concentrate and final tailings. Step 5: After filtering and drying the quartz concentrate, it is mixed with choline-based ionic liquid for leaching to obtain the leached solid phase; Step 6: The leached solid phase is filtered, washed and dried sequentially to obtain the concentrate product.

[0007] Furthermore, in step 5, the choline-based ionic liquid includes choline chloride, a hydrogen bond donor, and water, wherein the hydrogen bond donor is at least one of oxalic acid, malonic acid, citric acid, p-toluenesulfonic acid, ethylene glycol, and lactic acid.

[0008] Furthermore, in step 2, the pH of the primary slurry is 7.5-9.0 and the concentration is 25-35%.

[0009] Furthermore, in step 2, the mica modifier comprises, by mass ratio, 65-75 parts sodium hexametaphosphate, 10-20 parts carboxymethyl cellulose, and 10-20 parts starch, and the amount of mica modifier used is 200-500 g / t.

[0010] Further, in step 2, the mica collector comprises, by mass ratio, 45-55% sodium oleate, 20-30% cocoagulant, 10-20% alkyl alcohol, and 5-12% surfactant, and the amount of mica collector used is 300-700 g / t.

[0011] Furthermore, in step 3, the feldspar activator is at least one of oxalic acid, citric acid and tartaric acid, the amount of feldspar activator is 250~500g / t, and the activation time of the feldspar activator is 3~5min.

[0012] Further, in step 3, the cationic collector is at least one of modified coconut oil amine, tallow amine acetate, N-alkyl-1,3-propanediamine and hexadecyltrimethylammonium bromide, the amount of cationic collector is 150~350g / t, and the slurry conditioning time of the cationic collector is 2~3min.

[0013] Furthermore, in step 4, the quartz modifier comprises, by mass ratio, 60-70 parts sodium hexametaphosphate, 15-25 parts sodium carboxymethyl cellulose, and 10-20 parts oxalic acid, and the amount of quartz modifier used is 100-250 g / t.

[0014] Further, in step 4, the quartz collector comprises, by mass ratio, 50-60 parts sodium oleate, 20-30 parts etheramine acetate, 10-20 parts sodium alkyl sulfonate, and 5-12 parts polyoxyethylene ether, and the amount of quartz collector used is 180-450 g / t.

[0015] Furthermore, the composite foaming agent comprises 7-8 methyl isobutyl methanol and 2-3 polypropylene glycol by mass ratio, and the amount of composite foaming agent used is 20-80 g / t.

[0016] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects: A) The cascade flotation recovery method for iron tailings provided by this invention is based on the synergistic recovery approach of magnetic separation for iron recovery → sequential flotation separation of mica, feldspar, and quartz (neutral preferential flotation of mica, acid activation flotation separation of feldspar, and neutral enhanced separation of quartz) → deep iron removal by ionic liquid. Through the integrated design of segmented decoupling and step-by-step purification, it effectively alleviates the problems of insufficient dissociation of iron minerals, mica, feldspar, and quartz, difficulty in physical separation, and difficulty in separating silicate minerals in iron tailings. The process flow is simple, the closed-loop operation is stable, and it is highly adaptable to iron tailings with complex composition. Each concentrate product obtained can be directly used as an industrial raw material in the corresponding field, realizing the high-value utilization of all components of iron tailings. Compared with the treatment method of direct stockpiling, it greatly improves the resource utilization rate, reduces solid waste emissions, and has both environmental and economic benefits.

[0017] B) The step-flotation recovery method for iron tailings provided by this invention, in steps 2 to 4, utilizes the pH sensitivity difference in surface potential of mica, feldspar, and quartz. Mica has a low zero charge point (pH≈1~2) and can float under neutral conditions, while feldspar and quartz cannot float; feldspar contains Al³⁺. + At the site, after the feldspar activator is complexed and activated under acidic conditions, the cationic collector selectively adsorbs it; quartz has a high zero charge point (pH≈2~3) and a weak surface negative charge under near-neutral conditions. After activation by the quartz modifier, the quartz collector efficiently separates the three silicates, realizing single-channel separation, alleviating competitive adsorption and mutual inclusion during traditional flotation, and achieving efficient separation and comprehensive recovery of four valuable components: iron, mica, feldspar and quartz.

[0018] C) The cascade flotation recovery method for iron tailings provided by this invention, in step 5, introduces a deep iron removal process using choline-based ionic liquids to replace the traditional concentrated acid or hydrofluoric acid method. A eutectic solvent composed of choline chloride and hydrogen bond donors such as oxalic acid is used as the leaching medium, through the reaction of oxalate ions with Fe³⁺… + The stable complexation enables selective dissolution, and it is characterized by low toxicity, biodegradability, low volatility and recyclability, making it significantly more environmentally friendly than traditional strong acid impurity removal processes.

[0019] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained from what is particularly pointed out in the description and drawings. Attached Figure Description

[0020] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0021] Figure 1 A flowchart of the cascade flotation recovery method for iron tailings provided by the present invention. Detailed Implementation

[0022] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0023] This invention provides a method for the cascade flotation recovery of iron tailings, see [link to relevant documentation]. Figure 1 It includes the following steps: Step 1: Perform strong magnetic separation on the iron tailings slurry with a magnetic field strength of 1.0T~1.8T to obtain iron concentrate and non-magnetic products; Step 2: After adding mica modifier and mica collector to the non-magnetic product, a primary slurry is obtained. The primary slurry is subjected to one roughing, one scavenging and three cleaning processes to obtain mica concentrate and mica flotation tailings. Step 3: Add sulfuric acid to the mica flotation tailings to adjust the pH to an acidic environment (e.g., pH 2.5~3.5), then add feldspar activator and cationic collector in sequence to obtain a secondary slurry. Perform one roughing, two scavenging and three cleaning processes on the secondary slurry to obtain feldspar concentrate and feldspar flotation tailings (i.e. quartz rough concentrate). Step 4: Add sodium hydroxide to the quartz rough concentrate to adjust the pH of the slurry to a neutral condition of 6.5-7.5. Add quartz modifier, quartz collector and compound frother to obtain a three-stage slurry. Perform one roughing, one scavenging and two cleaning processes on the three-stage slurry to obtain quartz concentrate and final tailings. Step 5: After filtering and drying the quartz concentrate, it is mixed with choline-based ionic liquid for leaching to obtain the leached solid phase; Step 6: The leached solid phase is filtered, washed and dried sequentially to obtain the concentrate product.

[0024] For example, in step 5 above, the choline-based ionic liquid includes choline chloride, a hydrogen bond donor, and water, wherein the hydrogen bond donor is at least one of oxalic acid, malonic acid, citric acid, p-toluenesulfonic acid, ethylene glycol, and lactic acid.

[0025] Compared with existing technologies, the cascade flotation recovery method for iron tailings provided by this invention is based on the synergistic recovery approach of magnetic separation for iron recovery → sequential flotation separation of mica, feldspar, and quartz (neutral preferential flotation of mica, acid activation flotation separation of feldspar, and neutral enhanced separation of quartz) → deep iron removal by ionic liquid. Through the integrated design of segmented decoupling and step-by-step purification, it effectively alleviates the problems of insufficient dissociation of iron minerals, mica, feldspar, and quartz, difficulty in physical separation, and difficulty in separating silicate minerals in iron tailings. The process flow is simple, the closed-loop operation is stable, and it is highly adaptable to iron tailings with complex composition. The obtained concentrate products can be directly used as industrial raw materials in corresponding fields, realizing the high-value utilization of all components of iron tailings. Compared with the treatment method of direct stockpiling, it greatly improves resource utilization, reduces solid waste emissions, and has both environmental and economic benefits.

[0026] Specifically, in step 1 above, magnetic separation is used to capture iron minerals at a deep depth, reducing TFe in non-magnetic products to below 1%, and eliminating the potential interference and surface coverage of iron oxides on silicate flotation.

[0027] On the other hand, steps 2 to 4 above utilize the pH sensitivity differences in the surface potentials of mica, feldspar, and quartz. Mica has a low zero charge point (pH≈1~2) and can float under neutral conditions, while feldspar and quartz cannot float; feldspar contains Al³⁺. + At the site, after the feldspar activator is complexed and activated under acidic conditions, the cationic collector selectively adsorbs it; quartz has a high zero charge point (pH≈2~3) and a weak surface negative charge under near-neutral conditions. After activation by the quartz modifier, the quartz collector efficiently separates the three silicates, realizing single-channel separation, alleviating competitive adsorption and mutual inclusion during traditional flotation, and achieving efficient separation and comprehensive recovery of four valuable components: iron, mica, feldspar and quartz.

[0028] On the other hand, step 5 above replaces the traditional concentrated acid or hydrofluoric acid method by introducing a deep iron removal process using choline-based ionic liquids. It uses a eutectic solvent composed of choline chloride and hydrogen bond donors such as oxalic acid as the leaching medium, through which oxalate ions react with Fe³⁺... + The stable complexation enables selective dissolution, and it is characterized by low toxicity, biodegradability, low volatility and recyclability, making it significantly more environmentally friendly than traditional strong acid impurity removal processes.

[0029] It should be noted that, in practical applications, the iron tailings cascade flotation recovery method of the present invention yields a rich product structure and high added value. It can simultaneously obtain iron concentrate with an iron grade of ≥20%, and then further refine it to obtain iron concentrate with TFe≥55, mica concentrate with K2O≥7.0%, feldspar concentrate with (Na2O+K2O)≥10%, and quartz concentrate with SiO2≥99% and Fe2O3≤0.2%.

[0030] The method of the present invention is applicable to the cascade flotation of various iron tailings with SiO2 content of 60%~85%, TFe content of 5%~15%, feldspar mineral content of 5%~30%, and mica content of 2%~15%.

[0031] Furthermore, to address the issue of insufficient separation efficiency in the primary slurry, in step 2 above, the pH of the primary slurry is 7.5–9.0, and its concentration is 25–35%. This ensures the surface modification effect of the mica modifier on the mica minerals while maintaining good dispersibility in the primary slurry, mitigating the interference of slime adsorption on the adsorption of the mica collector on the target mineral surface, and improving the selectivity of mica flotation and concentrate grade.

[0032] Furthermore, in order to address the issue of low mica concentrate recovery, step 2 above, consisting of one roughing, one scavenging, and three cleaning processes, includes the following steps: Step 21: Perform a roughing process on the primary slurry for 3-5 minutes to obtain mica roughing concentrate and mica roughing tailings; Step 22: Perform a scavenging process on the mica roughing tailings for 2-3 minutes to obtain mica scavenging concentrate and mica tailings. Return the mica scavenging concentrate to step 21 and repeat the roughing process. The mica tailings will proceed to step 3. Step 23: Perform three fine treatments on the mica rough concentrate, each lasting 2-4 minutes. Return the mica first concentrate tailings to Step 21 for another rough treatment. Return the mica second concentrate tailings to the first fine treatment. Return the mica third concentrate tailings to the second fine treatment. Mix the mica first, second, and third concentrates to obtain the mica concentrate.

[0033] By performing the above flotation process on the primary slurry, the grade and recovery rate of mica concentrate can be gradually improved. Through the closed-loop process of sequential tailings return, the loss of target minerals can be reduced, further improving the recovery efficiency.

[0034] For example, in step 2 above, the mica modifier comprises, by mass ratio, 65-75 parts sodium hexametaphosphate, 10-20 parts carboxymethyl cellulose, and 10-20 parts starch, with a dosage of 200-500 g / t. Sodium hexametaphosphate achieves dispersion, carboxymethyl cellulose achieves selective inhibition, and starch achieves flocculation regulation. These three components work synergistically to alleviate problems such as severe mud formation, poor selectivity, and interference from fine mud in iron tailings.

[0035] The mica collector comprises, by mass ratio, 45-55% sodium oleate, 20-30% cocoamine, 10-20% alkyl alcohol, and 5-12% surfactant (e.g., Span 60), with a dosage of 300-700 g / t. Sodium oleate and cocoamine form a co-adsorption pair of anions and cations, the alkyl alcohol enhances hydrophobicity, and the surfactant optimizes dispersion and emulsification, collectively achieving highly efficient and selective collection under neutral conditions.

[0036] Furthermore, in order to address the issue of low feldspar concentrate recovery, step 3 above, consisting of one roughing, two scavenging, and three cleaning processes, includes the following steps: Step 31: Perform a roughing process on the secondary slurry for 4-6 minutes to obtain feldspar roughing concentrate and feldspar roughing tailings; Step 32: Perform a scavenging process on the feldspar roughing tailings. The scavenging process takes 3-4 minutes to obtain a feldspar scavenging concentrate and a feldspar tailings. The feldspar scavenging concentrate is returned to step 31 for another roughing process, and the feldspar tailings are taken to step 4. Step 33: Perform secondary scavenging on the feldspar tailings from the primary scavenging process. The secondary scavenging time is 2-3 minutes to obtain feldspar secondary scavenging concentrate and feldspar secondary scavenging tailings. The feldspar secondary scavenging concentrate is returned to step 32 to repeat the primary scavenging process. The feldspar secondary scavenging tailings are used as feldspar flotation tailings and enter step 4. Step 34: Perform three fine cleaning processes on the feldspar rough concentrate, each lasting 3-5 minutes. Return the feldspar tailings from step 1 to step 31 for another roughing process. Return the feldspar tailings from step 2 to the first fine cleaning process. Return the feldspar tailings from step 3 to the second fine cleaning process. The feldspar concentrates from steps 1, 2, and 3 are then mixed to form the feldspar concentrate.

[0037] By performing the above flotation process on the secondary slurry, the grade and recovery rate of feldspar concentrate can be gradually improved. Through the closed-loop process of sequential return, the loss of feldspar minerals can be reduced, and the recovery efficiency of feldspar components can be further improved.

[0038] For example, in step 3 above, the feldspar activator is at least one of oxalic acid, citric acid, and tartaric acid; the amount of feldspar activator is 250-500 g / t; and the activation time is 3-5 min. The mechanism of action of the feldspar activator is as follows: under acidic conditions, the polybasic acid radicals react with Al³⁺ on the feldspar surface. + The formation of stable complexes at the sites increases the surface negative charge density. At the same time, it dissolves the SiO2 microregions on the surface, exposing more active sites and providing selective adsorption sites for subsequent cationic collectors.

[0039] The cationic collector is at least one of modified coconut oil amine (modified coconut oil amine is the acetate produced by reacting coconut oil amine with glacial acetic acid at a mass ratio of 8~9:1), tallow amine acetate, N-alkyl-1,3-propanediamine and hexadecyltrimethylammonium bromide (CTAB). The amount of cationic collector used is 150~350g / t, and the slurry conditioning time of cationic collector is 2~3min. The mechanism of action of the cationic collector is: through the dual action of electrostatic adsorption and specific adsorption, a hydrophobic layer is preferentially formed on the surface of activated feldspar. Quartz has no Al sites on its surface and a high zero charge point, and is close to electroneutrality in this pH range. Therefore, the adsorption amount of cationic collector is significantly lower than that of feldspar.

[0040] Furthermore, in order to address the problem of low quartz concentrate recovery, step 4 above, consisting of one roughing, one scavenging, and two cleaning processes, includes the following steps: Step 41: Perform a roughing process on the tertiary slurry for 3-5 minutes to obtain quartz roughing concentrate and quartz roughing tailings; Step 42: Perform a scavenging process on the quartz roughing tailings for 2-3 minutes to obtain quartz scavenging concentrate and quartz tailings. Return the quartz scavenging concentrate to Step 41 and repeat the roughing process. The quartz tailings are the final tailings. Step 43: Perform two cleaning processes on the quartz rough concentrate, each lasting 2-4 minutes. Return the tailings from the first quartz concentrate to Step 41 for another roughing process. Return the tailings from the second quartz concentrate to the first cleaning process. The first and second quartz concentrates are then mixed to form the quartz concentrate.

[0041] For example, in step 4 above, the composition of the quartz modifier includes 60-70 parts sodium hexametaphosphate, 15-25 parts sodium carboxymethyl cellulose, and 10-20 parts oxalic acid by mass ratio, and the amount of quartz modifier used is 100-250 g / t. The mechanism of action of the quartz modifier is as follows: sodium hexametaphosphate achieves dispersion and dissociation of fine quartz and residual feldspar through electrostatic repulsion; sodium carboxymethyl cellulose selectively inhibits the active sites on the surface of residual feldspar; and oxalic acid activates the silanol groups on the quartz surface to enhance the adsorption of the collector. The three work together to construct a highly selective sorting environment.

[0042] The quartz collector is composed of sodium oleate (50-60 parts by mass), etheramine acetate (20-30 parts by mass), sodium alkyl sulfonate (10-20 parts by mass), and polyoxyethylene ether (5-12 parts by mass). The dosage of the quartz collector is 180-450 g / t. The mechanism of action of the quartz collector is as follows: sodium oleate provides basic anionic collecting performance; etheramine acetate enhances the hydrophobicity of the quartz surface through electrostatic adsorption and specific adsorption; sodium alkyl sulfonate enhances foam stability and inhibits fine mud entrainment; and polyoxyethylene ether optimizes slurry dispersibility and gas-liquid mineralization efficiency. The four components work synergistically to achieve efficient and selective quartz collection under near-neutral conditions.

[0043] The composite foaming agent consists of 7-8 methyl isobutyl methanol and 2-3 polypropylene glycol by mass ratio, and the amount of composite foaming agent used is 20-80 g / t.

[0044] Furthermore, to address the issue of insufficient leaching effect, in step 5 above, the molar ratio of choline chloride to hydrogen bond donor is 1:1~2. This ensures sufficient contact between the ionic liquid and the iron impurities on the surface of the quartz particles, guaranteeing the iron removal effect through leaching, while mitigating the increased system cost and subsequent separation difficulty caused by excessive hydrogen bond donor.

[0045] To further address the issue of insufficient leaching efficiency, in step 5 above, the total mass concentration of choline chloride and hydrogen bond donors in the choline-based ionic liquid is 40-60%, and the amount of choline-based ionic liquid used per ton of quartz concentrate is 100-300 L. This ensures sufficient wetting of iron-containing impurities on the surface of the quartz particles, providing ample reaction medium for selective complexation leaching, while mitigating the increased recovery costs due to excessive leaching agent dosage.

[0046] It is worth noting that leaching parameters also affect the leaching effect. For example, in step 5 above, the leaching pressure is atmospheric pressure, the leaching temperature is 60~90℃, and the leaching time is 1~3h. Under these process conditions, the complexation reaction rate of oxalate and iron ions can be guaranteed, while mitigating the increase in energy consumption due to excessively high temperatures. This achieves a balance between iron removal efficiency and energy consumption, ensuring that the iron content of the final quartz concentrate meets the standards.

[0047] Furthermore, in order to achieve the recycling of choline-based ionic liquids, the following steps are included between steps 5 and 6: Oxalic acid and choline chloride are added to the leachate to adjust the concentration to 40-60%, and the solution is returned to step 5 for recycling as a choline-based ionic liquid.

[0048] Furthermore, in order to solve the problems of fine mud agglomeration and heterogeneous flocculation in iron tailings slurry, the following steps are included before step 1 above: Iron tailings are concentrated and deslimed to a slurry concentration of 30-45% to remove interference from fine mud. Add a dispersant (e.g., at least one of sodium hexametaphosphate, water glass, tannic acid, sodium humate, and sodium polyacrylate) and a pH adjuster (e.g., at least one of sodium carbonate, sodium hydroxide, and lime), stir and adjust the slurry for 5-15 minutes to ensure uniform dispersion and adjust the pH of the slurry to 7.0-8.5, thus obtaining iron tailings slurry.

[0049] In this way, under weakly alkaline conditions, the dispersant can be effectively adsorbed onto the surface of fine minerals, and the electrostatic repulsion can inhibit the agglomeration of fine mud and heterogeneous flocculation. This can minimize the inclusion of magnetic iron minerals by non-magnetic gangue in the subsequent magnetic separation operation and improve the separation efficiency. At the same time, this environment also creates favorable conditions for the stabilizing effect of reagents and the selective separation of minerals in the subsequent flotation stage.

[0050] The dosage of dispersant is 80~200g / t, and the dosage of pH adjuster is 300~800g / t.

[0051] Furthermore, in order to address the issue of high impurity content of gas-liquid inclusions in the quartz rough concentrate, which affects the purity of subsequent concentrate products, the following steps are included between steps 3 and 4: Fracturing gas-liquid inclusions in quartz rough concentrate.

[0052] Specifically, fracturing gas-liquid inclusions in quartz rough concentrate includes the following steps: Step a: Place the quartz rough concentrate in a microwave environment for microwave treatment. The microwave selectively heats the polar fluid in the gas-liquid inclusions of the quartz rough concentrate, generating thermal stress at the interface between the gas-liquid inclusions and the quartz, inducing initial nano- to submicron-level cracks, and obtaining pre-fractured quartz rough concentrate. For example, the microwave processing frequency is 2.45 GHz, the microwave processing power is 3~6 kW, and the microwave processing time is 5~15 min, so that the polar fluid is heated to 200~400°C and the vapor pressure is increased to 3~8 MPa; Step b: Place the pre-fractured quartz rough concentrate in a microwave and ultrasonic environment for simultaneous microwave and ultrasonic treatment to obtain the treated quartz rough concentrate. For example, the microwave processing frequency is 2.45 GHz, the microwave processing power is 7~10 kW, the ultrasonic processing frequency is 20~40 kHz, and the ultrasonic processing power density is 0.5~2 W / cm². 2 The combined microwave and ultrasonic treatment time is 50-75 minutes, and the ambient temperature is 200-400℃. Step c: The treated quartz crude concentrate is loaded into a supercritical extraction vessel to form a fixed bed of quartz crude concentrate. Choline-based ionic liquid is injected, and dynamic circulation-assisted leaching is carried out under a supercritical CO2 atmosphere to remove lattice impurities and obtain leached quartz crude concentrate. The choline-based ionic liquid uses choline chloride as a hydrogen bond acceptor and one or more of citric acid, oxalic acid, and tartaric acid as hydrogen bond donors. Step d: The leached quartz crude concentrate is subjected to a mixed acid leaching of hydrochloric acid and oxalic acid, followed by drying and heat treatment to obtain the treated quartz crude concentrate.

[0053] In this way, on the one hand, microwave treatment alone, taking advantage of the fact that the dielectric constant of the polar fluid in the gas-liquid inclusion is much higher than that of the quartz crystal, achieves selective and rapid heating of the gas-liquid inclusion. The fluid inside the gas-liquid inclusion is heated, and its expansion pressure rises rapidly, generating non-uniform thermal stress at the interface between the gas-liquid inclusion and the quartz matrix. Initial cracks are induced only in the interface region, without causing large-scale damage to the intact crystal lattice inside the quartz matrix. On the other hand, by increasing the microwave treatment power, the high-pressure expansion state inside the gas-liquid inclusion is further maintained, and the initial crack begins to propagate along the interface direction. At the same time, the ultrasonic waves generate micro-jet impact and mechanical vibration through the cavitation effect, applying a dynamic alternating load at the crack tip. The two couple to form an asymmetric stress field, achieving non-contact and precise rupture of the gas-liquid inclusion. Furthermore, supercritical CO2 is used as a permeation medium, utilizing its low viscosity and high diffusivity to penetrate into the pre-ruptured nano- and submicron-sized cracks. Choline-based ionic liquids are used as leaching agents, utilizing their designed hydrogen bond network to selectively chelate metallic impurities. The two work together to achieve a deep purification mechanism of CO2 opening the circuit and ionic liquid removing impurities.

[0054] It should be noted that the microwave treatment stage in step a will generate an initial crack. The appearance of the initial crack will cause the internal volume of the gas-liquid inclusion to increase, thereby causing a decrease in internal pressure and a reduction in the static opening driving force. In step b, increasing the microwave treatment power can maintain the temperature of the fluid inside the gas-liquid inclusion during the crack propagation process, ensuring that the internal expansion pressure can continuously provide a driving force for the crack tip to open.

[0055] Example 1 This embodiment provides a method for the cascade flotation recovery of iron tailings, including the following steps: Step A: Concentrate and deslim the iron tailings to a slurry concentration of 44%, add dispersant (sodium hexametaphosphate) and pH adjuster (sodium carbonate), stir and adjust the slurry for 5 minutes to make the slurry evenly dispersed and adjust the pH of the slurry to 8.5 to obtain iron tailings slurry. The amount of dispersant used is 185g / t and the amount of pH adjuster used is 750g / t. Step B: Perform strong magnetic separation on the iron tailings slurry with a magnetic field strength of 1.8T to obtain iron concentrate and non-magnetic products; Step C: After adding mica modifier and mica collector to the non-magnetic product, a primary slurry is obtained. The primary slurry has a pH of 7.5 and a concentration of 25%. The mica modifier consists of sodium hexametaphosphate 75, carboxymethyl cellulose 10 and starch 15 by mass ratio, and the amount of mica modifier used is 250 g / t. The mica collector consists of sodium oleate 55, cocoa amine 20, alkyl alcohol 15 and surfactant 10 by mass ratio, and the amount of mica collector used is 400 g / t. Step D: Perform a roughing process on the primary slurry for 5 minutes to obtain mica roughing concentrate and mica roughing tailings; perform a scavenging process on the mica roughing tailings for 2 minutes to obtain mica scavenging concentrate and mica flotation tailings; repeat the roughing process on the mica scavenging concentrate; perform three cleaning processes on the mica roughing concentrate for 4 minutes each; repeat the roughing process on the mica primary concentrate tailings; return the mica secondary concentrate tailings to the primary cleaning process; return the mica tertiary concentrate tailings to the secondary cleaning process; and mix the mica primary concentrate, mica secondary concentrate, and mica tertiary concentrate to obtain the final mica concentrate. Step E: Add sulfuric acid to the mica flotation tailings to adjust the pH to 2.5, then add feldspar activator and cationic collector in sequence to obtain secondary pulp. The feldspar activator is oxalic acid, the dosage of which is 450 g / t, and the activation time is 3 min. The cationic collector is modified coconut oil amine (modified coconut oil amine is an acetate formed by the reaction of coconut oil amine and glacial acetic acid at a mass ratio of 9:1), the dosage of which is 150 g / t, and the pulp conditioning time is 3 min. Step F: Perform a first roughing process on the secondary slurry for 6 minutes to obtain feldspar roughing concentrate and feldspar roughing tailings; perform a first scavenging process on the feldspar roughing tailings for 3 minutes to obtain feldspar first scavenging concentrate and feldspar first tailings. Repeat the first roughing process on the feldspar scavenging concentrate; perform a second scavenging process on the feldspar first scavenging tailings for 3 minutes to obtain feldspar second scavenging concentrate and feldspar second scavenging tailings. Repeat the first scavenging process on the feldspar second scavenging concentrate. The feldspar second scavenging tailings are used as feldspar flotation tailings; perform a third cleaning process on the feldspar roughing concentrate for 3 minutes each. Repeat the first roughing process on the feldspar first concentrate tailings, return the second concentrate tailings to the first cleaning process, and return the third concentrate tailings to the second cleaning process. The feldspar first, second, and third concentrates are mixed to obtain the feldspar concentrate. Step G: Add sodium hydroxide to the quartz rough concentrate to adjust the slurry pH to 7.5, then add quartz modifier, quartz collector, and composite frother to obtain a three-stage slurry. The quartz modifier consists of sodium hexametaphosphate 68, sodium carboxymethyl cellulose 15, and oxalic acid 17 by mass ratio, with a dosage of 220 g / t. The quartz collector consists of sodium oleate 58, etheramine acetate 20, sodium alkyl sulfonate 17, and polyoxyethylene ether 5 by mass ratio, with a dosage of 200 g / t. The composite frother consists of methyl isobutyl methanol 8 and polypropylene glycol 2 by mass ratio, with a dosage of 30 g / t. Step H: Perform a roughing process on the tertiary slurry for 3 minutes to obtain quartz roughing concentrate and quartz roughing tailings. Perform a scavenging process on the quartz roughing tailings for 2 minutes to obtain quartz scavenging concentrate and quartz tailings. Repeat the roughing process on the quartz scavenging concentrate to obtain the final tailings. Perform two cleaning processes on the quartz roughing concentrate for 2 minutes each. Repeat the roughing process on the quartz primary concentrate tailings. Return the quartz secondary concentrate tailings to the primary cleaning process. Mix the quartz primary concentrate and quartz secondary concentrate to obtain the final quartz concentrate. Step I: After filtering and drying the quartz concentrate, it is mixed with a choline-based ionic liquid for leaching to obtain a leaching solid phase. The choline-based ionic liquid includes choline chloride, a hydrogen bond donor, and deionized water. The hydrogen bond donor is oxalic acid, and the molar ratio of choline chloride to hydrogen bond donor is 1:2. The total mass concentration of choline chloride and hydrogen bond donor in the choline-based ionic liquid is 60%. The amount of choline-based ionic liquid used per ton of quartz concentrate is 100L. The leaching pressure is atmospheric pressure, the leaching temperature is 60℃, and the leaching time is 3h. Step J: The leached solid phase is sequentially filtered, washed, and dried to obtain the concentrate product.

[0056] The obtained products were tested and found that the iron grade of the iron concentrate was 18%, the K2O content of the mica concentrate was 7.4%, the (Na2O+K2O) content of the feldspar concentrate was 10.8%, the SiO2 content of the concentrate product was 99.3%, and the Fe2O3 content was 0.10%.

[0057] Example 2 This embodiment provides a method for the cascade flotation recovery of iron tailings, including the following steps: Step A: Concentrate and deslim the iron tailings to a slurry concentration of 32%, add dispersant (water glass) and pH adjuster (sodium hydroxide), stir and adjust the slurry for 15 minutes to make the slurry evenly dispersed and adjust the pH of the slurry to 7.0 to obtain iron tailings slurry. The amount of dispersant used is 90g / t and the amount of pH adjuster used is 350g / t. Step B: Perform strong magnetic separation on the iron tailings slurry with a magnetic field strength of 1.0T to obtain iron concentrate and non-magnetic products; Step C: After adding mica modifier and mica collector to the non-magnetic product, a primary slurry is obtained. The primary slurry has a pH of 9.0 and a concentration of 35%. The mica modifier consists of sodium hexametaphosphate 65, carboxymethyl cellulose 15 and starch 20 by mass ratio, and the amount of mica modifier used is 250 g / t. The mica collector consists of sodium oleate 55, cocoa amine 20, alkyl alcohol 15 and surfactant 10 by mass ratio, and the amount of mica collector used is 400 g / t. Step D: Perform a roughing process on the primary slurry for 3 minutes to obtain mica roughing concentrate and mica roughing tailings; perform a scavenging process on the mica roughing tailings for 3 minutes to obtain mica scavenging concentrate and mica flotation tailings; repeat the roughing process on the mica scavenging concentrate; perform three cleaning processes on the mica roughing concentrate for 2 minutes each; repeat the roughing process on the mica primary concentrate tailings; return the mica secondary concentrate tailings to the primary cleaning process; return the mica tertiary concentrate tailings to the secondary cleaning process; and mix the mica primary concentrate, mica secondary concentrate, and mica tertiary concentrate to obtain the final mica concentrate. Step E: Add sulfuric acid to the mica flotation tailings to adjust the pH to 3.0, then add feldspar activator and cationic collector in sequence to obtain secondary pulp. The feldspar activator is citric acid, the dosage of which is 300 g / t, and the activation time is 5 min. The cationic collector is modified coconut oil amine (modified coconut oil amine is an acetate formed by the reaction of coconut oil amine and glacial acetic acid at a mass ratio of 8:1), the dosage of which is 350 g / t, and the pulp conditioning time is 2 min. Step F: Perform a first roughing process on the secondary slurry for 5 minutes to obtain feldspar roughing concentrate and feldspar roughing tailings; perform a first scavenging process on the feldspar roughing tailings for 4 minutes to obtain feldspar first scavenging concentrate and feldspar first tailings. Repeat the first roughing process on the feldspar scavenging concentrate; perform a second scavenging process on the feldspar first scavenging tailings for 2 minutes to obtain feldspar second scavenging concentrate and feldspar second scavenging tailings. Repeat the first scavenging process on the feldspar second scavenging concentrate. The feldspar second scavenging tailings are used as feldspar flotation tailings; perform a third cleaning process on the feldspar roughing concentrate for 4 minutes each. Repeat the first roughing process on the feldspar first concentrate tailings, return the second concentrate tailings to the first cleaning process, and return the third concentrate tailings to the second cleaning process. The feldspar first, second, and third concentrates are mixed to obtain the feldspar concentrate. Step G: Add sodium hydroxide to the quartz rough concentrate to adjust the slurry pH to 7.5, then add quartz modifier, quartz collector, and composite frother to obtain a three-stage slurry. The quartz modifier consists of 60g sodium hexametaphosphate, 25g sodium carboxymethyl cellulose, and 15g oxalic acid by mass ratio, with a dosage of 120g / t. The quartz collector consists of 55g sodium oleate, 25g etheramine acetate, 10g sodium alkyl sulfonate, and 10g polyoxyethylene ether by mass ratio, with a dosage of 450g / t. The composite frother consists of 7g methyl isobutyl methanol and 3g polypropylene glycol by mass ratio, with a dosage of 60g / t. Step H: Perform a roughing process on the tertiary slurry for 4 minutes to obtain quartz roughing concentrate and quartz roughing tailings. Perform a scavenging process on the quartz roughing tailings for 3 minutes to obtain quartz scavenging concentrate and quartz tailings. Repeat the roughing process on the quartz scavenging concentrate to obtain the final tailings. Perform two cleaning processes on the quartz roughing concentrate for 4 minutes each. Repeat the roughing process on the quartz primary concentrate tailings. Return the quartz secondary concentrate tailings to the primary cleaning process. Mix the quartz primary concentrate and quartz secondary concentrate to obtain the final quartz concentrate. Step I: After filtering and drying the quartz concentrate, it is mixed with a choline-based ionic liquid for leaching to obtain a leaching solid phase. The choline-based ionic liquid includes choline chloride, a hydrogen bond donor, and deionized water. The hydrogen bond donor is malonic acid, and the molar ratio of choline chloride to hydrogen bond donor is 1:1. The total mass concentration of choline chloride and hydrogen bond donor in the choline-based ionic liquid is 50%. The amount of choline-based ionic liquid used per ton of quartz concentrate is 200L. The leaching pressure is atmospheric pressure, the leaching temperature is 90℃, and the leaching time is 1h. Step J: The leached solid phase is sequentially filtered, washed, and dried to obtain the concentrate product.

[0058] The obtained products were tested and found that the iron grade of the iron concentrate was 21%, the K2O content of the mica concentrate was 7.0%, the (Na2O+K2O) content of the feldspar concentrate was 11%, the SiO2 content of the concentrate product was 99.1%, and the Fe2O3 content was 0.14%.

[0059] Example 3 This embodiment provides a method for the cascade flotation recovery of iron tailings, including the following steps: Step A: Concentrate and deslim the iron tailings to a slurry concentration of 30%, add dispersant (tannic acid) and pH adjuster (lime), stir and adjust the slurry for 10 minutes to make the slurry evenly dispersed and adjust the pH of the slurry to 7.5 to obtain iron tailings slurry. The amount of dispersant used is 150g / t and the amount of pH adjuster used is 500g / t. Step B: Perform strong magnetic separation on the iron tailings slurry with a magnetic field strength of 1.5T to obtain iron concentrate and non-magnetic products; Step C: After adding mica modifier and mica collector to the non-magnetic product, a primary slurry is obtained. The primary slurry has a pH of 8.0 and a concentration of 30%. The mica modifier consists of sodium hexametaphosphate 68, carboxymethyl cellulose 20 and starch 12 by mass ratio, and the amount of mica modifier used is 450 g / t. The mica collector consists of sodium oleate 45, cocoamine 28, alkyl alcohol 20 and surfactant 7 by mass ratio, and the amount of mica collector used is 650 g / t. Step D: Perform a roughing process on the primary slurry for 4 minutes to obtain mica roughing concentrate and mica roughing tailings; perform a scavenging process on the mica roughing tailings for 3 minutes to obtain mica scavenging concentrate and mica flotation tailings; repeat the roughing process on the mica scavenging concentrate; perform three cleaning processes on the mica roughing concentrate for 3 minutes each; repeat the roughing process on the mica primary concentrate tailings; return the mica secondary concentrate tailings to the primary cleaning process; return the mica tertiary concentrate tailings to the secondary cleaning process; and mix the mica primary concentrate, mica secondary concentrate, and mica tertiary concentrate to obtain the final mica concentrate. Step E: After adjusting the pH to an acidic environment by adding sulfuric acid to the mica flotation tailings, feldspar activator and cationic collector are added sequentially to obtain a secondary pulp. The feldspar activator is at least one of oxalic acid, citric acid and tartaric acid, the dosage of the feldspar activator is 500 g / t, and the activation time of the feldspar activator is 4 min. The cationic collector is tallow amine acetate, the dosage of the cationic collector is 280 g / t, and the pulp conditioning time of the cationic collector is 2 min. Step F: Perform a first roughing process on the secondary slurry for 4 minutes to obtain feldspar roughing concentrate and feldspar roughing tailings; perform a first scavenging process on the feldspar roughing tailings for 4 minutes to obtain feldspar first scavenging concentrate and feldspar first tailings. Repeat the first roughing process on the feldspar scavenging concentrate; perform a second scavenging process on the feldspar first scavenging tailings for 3 minutes to obtain feldspar second scavenging concentrate and feldspar second scavenging tailings. Repeat the first scavenging process on the feldspar second scavenging concentrate. The feldspar second scavenging tailings are used as feldspar flotation tailings; perform a third cleaning process on the feldspar roughing concentrate for 3 minutes each. Repeat the first roughing process on the feldspar first concentrate tailings, return the second concentrate tailings to the first cleaning process, and return the third concentrate tailings to the second cleaning process. The feldspar first, second, and third concentrates are mixed to obtain the feldspar concentrate. Step G: The quartz rough concentrate is placed in a microwave environment for microwave treatment. The microwave selectively heats the polar fluid in the gas-liquid inclusions of the quartz rough concentrate, generating thermal stress at the interface between the gas-liquid inclusions and the quartz, inducing initial nano- to submicron-level cracks, and obtaining pre-fractured quartz rough concentrate. The microwave treatment frequency is 2.45 GHz, the microwave treatment power is 3 kW, and the microwave treatment time is 10 min, so that the polar fluid is heated to 350°C and the vapor pressure is increased to 4 MPa. Step H: The pre-fractured quartz rough concentrate is placed in a microwave and ultrasonic environment for simultaneous microwave and ultrasonic treatment to obtain the treated quartz rough concentrate. The microwave treatment frequency is 2.45 GHz, the microwave treatment power is 8 kW, the ultrasonic treatment frequency is 40 kHz, and the ultrasonic treatment power density is 2 W / cm³. 2 The combined microwave and ultrasonic treatment time was 50 minutes, and the ambient temperature was 350℃. Step I: The treated quartz crude concentrate is loaded into a supercritical extraction vessel to form a fixed bed of quartz crude concentrate. A choline-based ionic liquid is injected, and dynamic circulation-assisted leaching is carried out under a supercritical CO2 atmosphere to remove lattice impurities and obtain the leached quartz crude concentrate. The choline-based ionic liquid uses choline chloride as a hydrogen bond acceptor and citric acid as a hydrogen bond donor. Step J: The leached quartz crude concentrate is subjected to a mixed acid leaching of hydrochloric acid and oxalic acid, followed by drying and heat treatment to obtain the treated quartz crude concentrate.

[0060] Step K: Add sodium hydroxide to the quartz concentrate to adjust the slurry pH to neutral conditions, then add quartz modifier, quartz collector, and composite frother to obtain a three-stage slurry. The quartz modifier consists of sodium hexametaphosphate 65, sodium carboxymethyl cellulose 16, and oxalic acid 19 by mass ratio, with a dosage of 150 g / t. The quartz collector consists of sodium oleate 51, etheramine acetate 28, sodium alkyl sulfonate 12, and polyoxyethylene ether 9 by mass ratio, with a dosage of 375 g / t. The composite frother consists of methyl isobutyl methanol 7 and polypropylene glycol 3 by mass ratio, with a dosage of 50 g / t. Step L: Perform a roughing process on the tertiary slurry for 5 minutes to obtain quartz roughing concentrate and quartz roughing tailings. Perform a scavenging process on the quartz roughing tailings for 3 minutes to obtain quartz scavenging concentrate and quartz tailings. Repeat the roughing process on the quartz scavenging concentrate to obtain the final tailings. Perform two cleaning processes on the quartz roughing concentrate for 2 minutes each. Repeat the roughing process on the quartz primary concentrate tailings. Return the quartz secondary concentrate tailings to the primary cleaning process. Mix the quartz primary concentrate and quartz secondary concentrate to obtain the final quartz concentrate. Step M: After filtering and drying the quartz concentrate, it is leached with a choline-based ionic liquid to obtain a leaching solid phase. The choline-based ionic liquid includes choline chloride, a hydrogen bond donor, and deionized water. The hydrogen bond donor is citric acid, and the molar ratio of choline chloride to hydrogen bond donor is 1:1. The total mass concentration of choline chloride and hydrogen bond donor in the choline-based ionic liquid is 40%. The amount of choline-based ionic liquid used per ton of quartz concentrate is 250L. The leaching pressure is atmospheric pressure, the leaching temperature is 70℃, and the leaching time is 2h. Step N: The leached solid phase is sequentially filtered, washed, and dried to obtain the concentrate product.

[0061] The obtained products were tested and found that the iron grade of the iron concentrate was 19%, the K2O content of the mica concentrate was 7.9%, the (Na2O+K2O) content of the feldspar concentrate was 12.1%, the SiO2 content of the concentrate product was 99.8%, and the Fe2O3 content was 0.06%.

[0062] Example 4 This embodiment provides a method for the cascade flotation recovery of iron tailings, including the following steps: Step A: Concentrate and deslim the iron tailings to a slurry concentration of 30%, add dispersant (sodium humate and sodium polyacrylate) and pH adjuster (sodium hydroxide and lime), stir and adjust the slurry for 10 minutes to make the slurry evenly dispersed and adjust the pH of the slurry to 7.5 to obtain iron tailings slurry. The amount of dispersant used is 150g / t and the amount of pH adjuster used is 500g / t. Step B: Perform strong magnetic separation on the iron tailings slurry with a magnetic field strength of 1.5T to obtain iron concentrate and non-magnetic products; Step C: After adding mica modifier and mica collector to the non-magnetic product, a primary slurry is obtained. The primary slurry has a pH of 8.0 and a concentration of 30%. The mica modifier consists of sodium hexametaphosphate 68, carboxymethyl cellulose 20 and starch 12 by mass ratio, and the amount of mica modifier used is 450 g / t. The mica collector consists of sodium oleate 45, cocoamine 28, alkyl alcohol 20 and surfactant 7 by mass ratio, and the amount of mica collector used is 650 g / t. Step D: Perform a roughing process on the primary slurry for 4 minutes to obtain mica roughing concentrate and mica roughing tailings; perform a scavenging process on the mica roughing tailings for 3 minutes to obtain mica scavenging concentrate and mica flotation tailings; repeat the roughing process on the mica scavenging concentrate; perform three cleaning processes on the mica roughing concentrate for 3 minutes each; repeat the roughing process on the mica primary concentrate tailings; return the mica secondary concentrate tailings to the primary cleaning process; return the mica tertiary concentrate tailings to the secondary cleaning process; and mix the mica primary concentrate, mica secondary concentrate, and mica tertiary concentrate to obtain the final mica concentrate. Step E: Add sulfuric acid to the mica flotation tailings to adjust the pH to 2.5, then add feldspar activator and cationic collector in sequence to obtain secondary pulp. The feldspar activator is citric acid and tartaric acid, the dosage of feldspar activator is 500 g / t, and the activation time of feldspar activator is 4 min. The cationic collector is N-alkyl-1,3-propanediamine and hexadecyltrimethylammonium bromide, the dosage of cationic collector is 280 g / t, and the pulp conditioning time of cationic collector is 2 min. Step F: Perform a first roughing process on the secondary slurry for 4 minutes to obtain feldspar roughing concentrate and feldspar roughing tailings; perform a first scavenging process on the feldspar roughing tailings for 4 minutes to obtain feldspar first scavenging concentrate and feldspar first tailings. Repeat the first roughing process on the feldspar scavenging concentrate; perform a second scavenging process on the feldspar first scavenging tailings for 3 minutes to obtain feldspar second scavenging concentrate and feldspar second scavenging tailings. Repeat the first scavenging process on the feldspar second scavenging concentrate. The feldspar second scavenging tailings are used as feldspar flotation tailings; perform a third cleaning process on the feldspar roughing concentrate for 3 minutes each. Repeat the first roughing process on the feldspar first concentrate tailings, return the second concentrate tailings to the first cleaning process, and return the third concentrate tailings to the second cleaning process. The feldspar first, second, and third concentrates are mixed to obtain the feldspar concentrate. Step G: The quartz rough concentrate is placed in a microwave environment for microwave treatment. The microwave selectively heats the polar fluid in the gas-liquid inclusions of the quartz rough concentrate, generating thermal stress at the interface between the gas-liquid inclusions and the quartz, inducing initial nano- to submicron-level cracks, and obtaining pre-fractured quartz rough concentrate. The microwave treatment frequency is 2.45 GHz, the microwave treatment power is 6 kW, and the microwave treatment time is 15 min, which raises the temperature of the polar fluid to 400 ℃ and increases the vapor pressure to 6 MPa. Step H: The pre-fractured quartz rough concentrate is placed in a microwave and ultrasonic environment for simultaneous microwave and ultrasonic treatment to obtain the treated quartz rough concentrate. The microwave treatment frequency is 2.45 GHz, the microwave treatment power is 10 kW, the ultrasonic treatment frequency is 20 kHz, and the ultrasonic treatment power density is 0.5 W / cm³. 2 The combined microwave and ultrasonic treatment time was 75 minutes, and the ambient temperature was 250℃. Step I: The treated quartz crude concentrate is loaded into a supercritical extraction vessel to form a fixed bed of quartz crude concentrate. Choline-based ionic liquid is injected, and dynamic circulation-assisted leaching is carried out under a supercritical CO2 atmosphere to remove lattice impurities and obtain leached quartz crude concentrate. The choline-based ionic liquid uses choline chloride as a hydrogen bond acceptor and oxalic acid and tartaric acid as hydrogen bond donors. Step J: The leached quartz crude concentrate is subjected to a mixed acid leaching of hydrochloric acid and oxalic acid, followed by drying and heat treatment to obtain the treated quartz crude concentrate.

[0063] Step K: Add sodium hydroxide to the quartz rough concentrate to adjust the slurry pH to 7, then add quartz modifier, quartz collector, and composite frother to obtain a three-stage slurry. The quartz modifier consists of sodium hexametaphosphate 65, sodium carboxymethyl cellulose 16, and oxalic acid 19 by mass ratio, with a dosage of 150 g / t. The quartz collector consists of sodium oleate 51, etheramine acetate 28, sodium alkyl sulfonate 12, and polyoxyethylene ether 9 by mass ratio, with a dosage of 375 g / t. The composite frother consists of methyl isobutyl methanol 7 and polypropylene glycol 3 by mass ratio, with a dosage of 50 g / t. Step L: Perform a roughing process on the tertiary slurry for 5 minutes to obtain quartz roughing concentrate and quartz roughing tailings. Perform a scavenging process on the quartz roughing tailings for 3 minutes to obtain quartz scavenging concentrate and quartz tailings. Repeat the roughing process on the quartz scavenging concentrate to obtain the final tailings. Perform two cleaning processes on the quartz roughing concentrate for 2 minutes each. Repeat the roughing process on the quartz primary concentrate tailings. Return the quartz secondary concentrate tailings to the primary cleaning process. Mix the quartz primary concentrate and quartz secondary concentrate to obtain the final quartz concentrate. Step M: After filtering and drying the quartz concentrate, it is leached with a choline-based ionic liquid to obtain a leaching solid phase. The choline-based ionic liquid includes choline chloride, hydrogen bond donors, and deionized water. The hydrogen bond donors are ethylene glycol and lactic acid. The molar ratio of choline chloride to hydrogen bond donors is 1:1. The total mass concentration of choline chloride and hydrogen bond donors in the choline-based ionic liquid is 40%. The amount of choline-based ionic liquid used per ton of quartz concentrate is 250L. The leaching pressure is atmospheric pressure, the leaching temperature is 70℃, and the leaching time is 2h. Step N: The leached solid phase is sequentially filtered, washed, and dried to obtain the concentrate product.

[0064] The obtained products were tested and found that the iron grade of the iron concentrate was 19%, the K2O content of the mica concentrate was 8.1%, the (Na2O+K2O) content of the feldspar concentrate was 11.9%, the SiO2 content of the concentrate product was 99.7%, and the Fe2O3 content was 0.08%.

[0065] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for the cascade flotation recovery of iron tailings, characterized in that, Includes the following steps: Step 1: Perform magnetic separation on the iron tailings slurry to obtain iron concentrate and non-magnetic products; Step 2: After adding mica modifier and mica collector to the non-magnetic product, a primary slurry is obtained. The primary slurry is then subjected to one roughing, one scavenging, and three cleaning processes to obtain mica concentrate and mica tailings. Step 3: After adding sulfuric acid to the mica tailings to adjust the pH to an acidic environment, feldspar activator and cationic collector are added in sequence to obtain a secondary slurry. The secondary slurry is then subjected to one roughing, two scavenging and three cleaning processes to obtain feldspar concentrate and quartz rough concentrate. Step 4: Add sodium hydroxide to the quartz rough concentrate to adjust the pH of the slurry to neutral conditions, add quartz adjuster, quartz collector and compound frother to obtain a three-stage slurry, and perform one roughing, one scavenging and two cleaning processes on the three-stage slurry to obtain quartz concentrate and final tailings. Step 5: After filtering and drying the quartz concentrate, it is mixed with choline-based ionic liquid for leaching to obtain the leached solid phase; Step 6: The leached solid phase is filtered, washed and dried sequentially to obtain the concentrate product.

2. The method for staged flotation recovery of iron tailings according to claim 1, characterized in that, In step 5, the choline-based ionic liquid includes choline chloride, a hydrogen bond donor, and water. The hydrogen bond donor is at least one of oxalic acid, malonic acid, citric acid, p-toluenesulfonic acid, ethylene glycol, and lactic acid.

3. The method for staged flotation recovery of iron tailings according to claim 1, characterized in that, In step 2, the primary slurry has a pH of 7.5 to 9.0 and a concentration of 25 to 35%.

4. The method for staged flotation recovery of iron tailings according to claim 1, characterized in that, In step 2, the mica modifier comprises, by mass ratio, 65-75 parts sodium hexametaphosphate, 10-20 parts carboxymethyl cellulose, and 10-20 parts starch, and the amount of mica modifier used is 200-500 g / t.

5. The method for staged flotation recovery of iron tailings according to claim 1, characterized in that, In step 2, the mica collector comprises, by mass ratio, 45-55 sodium oleate, 20-30 cocoaluminate, 10-20 alkyl alcohol and 5-12 surfactant, and the amount of mica collector used is 300-700 g / t.

6. The method for staged flotation recovery of iron tailings according to claim 1, characterized in that, In step 3, the feldspar activator is at least one of oxalic acid, citric acid and tartaric acid, the amount of the feldspar activator is 250~500g / t, and the activation time of the feldspar activator is 3~5min.

7. The method for staged flotation recovery of iron tailings according to claim 1, characterized in that, In step 3, the cationic collector is at least one of modified coconut oil amine, tallow amine acetate, N-alkyl-1,3-propanediamine and hexadecyltrimethylammonium bromide, the amount of the cationic collector is 150~350g / t, and the slurry conditioning time of the cationic collector is 2~3min.

8. The method for staged flotation recovery of iron tailings according to claim 1, characterized in that, In step 4, the quartz modifier comprises, by mass ratio, 60-70 parts sodium hexametaphosphate, 15-25 parts sodium carboxymethyl cellulose, and 10-20 parts oxalic acid, and the amount of the quartz modifier used is 100-250 g / t.

9. The method for staged flotation recovery of iron tailings according to claim 1, characterized in that, In step 4, the quartz collector comprises, by mass ratio, 50-60 parts sodium oleate, 20-30 parts etheramine acetate, 10-20 parts sodium alkyl sulfonate, and 5-12 parts polyoxyethylene ether, and the amount of the quartz collector used is 180-450 g / t.

10. The method for staged flotation recovery of iron tailings according to claim 1, characterized in that, The composite foaming agent comprises 7-8 g of methyl isobutyl methanol and 2-3 g of polypropylene glycol by mass ratio, and the amount of the composite foaming agent is 20-80 g / t.

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