High-alkalinity copper oxide ore flotation method capable of avoiding out-of-control vulcanization activation

Abstract

The invention discloses a high-alkalinity copper oxide ore flotation method capable of avoiding out-of-control vulcanization and activation in the field of mineral processing, and aims at solving the technical problem that in high-alkalinity copper oxide ore flotation, a vulcanizing agent is prone to ineffective reaction with gangue, and consequently the vulcanization efficiency is low. A core-shell structure metal organic framework modified material is introduced to realize accurate regulation and control of the vulcanization process. The modified material takes a zeolite imidate framework material as a core, and is prepared through a multi-step process including chitosan modification, metal site anchoring, functional packaging and the like. The flotation process comprises the four key steps of ore pulp pretreatment and pH adjustment, segmented vulcanization activation, combined collector flotation and closed-loop flotation separation. According to the method, the vulcanization efficiency of the copper oxide mineral can be remarkably improved, the side reaction of the vulcanizing agent and gangue mineral is inhibited, the copper recovery rate and the concentrate grade are greatly improved while the dosage of the vulcanizing agent is reduced, the modified material can be recycled, and the method has the advantages of being low in cost, high in efficiency and environmentally friendly.

Description

Technical Field

[0001] This invention belongs to the field of mineral processing technology, and specifically relates to a flotation method for highly alkaline copper oxide ore that avoids runaway sulfidation activation. Background Technology

[0002] As an important source of copper metal resources, the efficient recovery and utilization of copper oxide ores has always been a key research direction in my country's mineral resource processing field. With the decreasing availability of easily processed copper sulfide ores, copper oxide ores, characterized by low grade, complex intergrowth relationships, and diverse mineral compositions, have become one of the main raw materials for copper smelting. However, copper oxide ores differ significantly from copper sulfide ores in their physicochemical properties and beneficiation properties, leading to numerous technical bottlenecks in their flotation recovery. In particular, for copper oxide ores hosted in high-calcium-magnesium alkaline gangue systems, the natural pH of the pulp is often high under conventional flotation conditions, resulting in a sharp deterioration in the effectiveness of traditional sulfide activation flotation processes. These high-alkaline copper oxide ores are widely distributed in my country and have significant industrial value, but due to low flotation efficiency, high reagent consumption, and poor technical and economic indicators, they have long been unable to be effectively developed and utilized, resulting in a serious waste of mineral resources.

[0003] In highly alkaline slurry environments, the conventional sulfidation activation process for copper oxide ores suffers from serious technical defects. First, the interaction efficiency between the sulfiding agent and the surface of copper oxide minerals is significantly reduced, while ineffective side reactions with alkaline gangue minerals are exacerbated, resulting in a significant increase in the amount of sulfiding agent required with minimal effect. Second, in highly alkaline environments, calcium and magnesium ions easily form hydroxide precipitates. These fine precipitates mechanically cover the surface of the target mineral, forming a physical barrier that hinders effective contact between the sulfiding agent and the copper oxide minerals. Simultaneously, the high concentration of hydroxide ions in the slurry intensifies hydroxylation on the mineral surface, making the existing sulfidation film unstable and prone to detachment. Furthermore, the electrochemical effects during grinding and agitation cause copper ions to dissolve, which in turn activate gangue minerals, reducing the floatability difference between the target mineral and gangue minerals and deteriorating flotation selectivity. Currently, ammonium salts are commonly used in industry as activators to improve sulfidation effects. However, the activation effect of ammonium salts is limited under high alkaline conditions and they are prone to causing environmental pollution, making it difficult to fundamentally solve the technical problem of flotation of highly alkaline copper oxide ores.

[0004] To address the technical bottlenecks in the flotation of highly alkaline copper oxide ores, researchers both domestically and internationally have undertaken various attempts and explorations. Early research mainly focused on the development of novel sulfiding agents and the combined use of existing reagents, but failed to fundamentally solve the problem of ineffective reactions between sulfiding agents and gangue minerals. The subsequently developed ammonium salt activation method, while improving sulfidation efficiency to some extent, suffers from poor environmental friendliness and insufficient stability under extremely high alkalinity conditions. In recent years, some researchers have begun to focus on mineral surface modification technologies, altering mineral surface properties through pretreatment; however, these methods are often complex in process and costly, making industrial application difficult. Therefore, developing a novel technology capable of precisely controlling the sulfidation process under high alkalinity conditions, effectively suppressing ineffective sulfiding agent consumption, and significantly improving the flotation efficiency of copper oxide ores has become a key scientific and technological problem urgently needing to be solved in this field. This technology should be able to identify the differences in surface properties between copper oxide ores and gangue minerals, achieving directional adsorption and controllable release of sulfiding agents on the target mineral surface, thereby significantly improving flotation indicators while reducing reagent dosage, providing technical support for the efficient utilization of abundant, highly alkaline, and difficult-to-process copper oxide ores. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a flotation method for highly alkaline copper oxide ores that avoids uncontrolled sulfidation activation.

[0006] A first aspect of the present invention provides a method for flotation of highly alkaline copper oxide ore to avoid runaway sulfidation activation, comprising the following steps: S1. The high-alkalinity copper oxide ore is crushed and ground to prepare a slurry. Under stirring conditions, a core-shell structured metal-organic framework modifier is added to the slurry, along with sodium carbonate, to adjust the pH of the slurry to 9.0-9.5. S2. Add sodium sulfide to the slurry and stir. The sodium sulfide is added in two parts: first, add 30-40% of the total sodium sulfide, and then add 60-70% of the total sodium sulfide after an interval of 3-5 minutes. S3. Add a combined collector to the slurry, the combined collector being a mixture of butyl xanthate and benzohydroxyxamic acid; then add pine oil and stir. S4. Start the flotation machine aeration system to carry out flotation separation; the foam rich in copper minerals is scraped off by the scraper and enters the concentrate collection tank; the gangue minerals are retained in the tank and discharged as tailings; the flotation process adopts a closed-loop process of roughing, cleaning I and cleaning II, scavenging I and scavenging II; in the cleaning stage, core-shell structured metal-organic framework modifiers are added to the slurry; after flotation, the enriched copper concentrate is filtered and dried; the core-shell structured metal-organic framework modifiers are recovered and regenerated from the tailings.

[0007] The core of the reaction mechanism of the high-alkalinity copper oxide ore flotation method for avoiding uncontrolled sulfidation activation in this invention lies in the precise control and enhancement of the sulfidation process using the aforementioned modified material, thereby overcoming the problem of low sulfidation efficiency under high-alkalinity conditions. When the modified material is added to the high-alkalinity slurry, the responsive polymer in its outer shell swells within a set weakly alkaline range, regulating the diffusion rate of sulfiding agent molecules from the internal pores into the solution phase. The pre-anchored copper ion sites within the material exhibit specific adsorption and enrichment effects on active sulfur components such as sulfide ions in the solution, effectively increasing the local sulfur reagent concentration at the mineral interface. More importantly, these sites can catalyze redox reactions between sulfide ions and copper atoms on the surface of copper oxide minerals, promoting the selective formation of a dense and stable copper sulfide film on the surface of minerals such as malachite. Its function is similar to that of a copper-ammonium complex activator, but avoids the use of ammonium salts and the potential environmental problems they may cause. The presence of the modified material significantly inhibited the ineffective reaction between the sulfiding agent and alkaline gangue minerals such as calcium and magnesium in the pulp, as well as the activation of gangue minerals by copper ions generated during grinding due to electrochemical action. In the combined collector stage, the surface structure of the modified material synergistically adsorbed with xanthate and hydroxamic acid collectors, further enhancing the hydrophobicity of the sulfided mineral surface and improving flotation selectivity. The entire flotation system, through a strategy of staged addition of sulfiding agents and modified materials, supplemented by necessary closed-loop processes and middlings reprocessing, optimized sulfidation kinetics and enhanced the stability of the sulfidation film, thereby significantly improving the flotation recovery and concentrate grade of oxidized copper ore under high-alkali conditions, while reducing reagent consumption.

[0008] As a preferred embodiment of the present invention, in step S1, the slurry concentration is 30-40% and the stirring time is 10-15 min.

[0009] As a preferred embodiment of the present invention, in step S2, the stirring speed is 800-1000 rpm.

[0010] As a preferred embodiment of the present invention, in step S3, the mass ratio of butyl xanthate to benzohydroxyxamic acid is 3:1.

[0011] As a preferred embodiment of the present invention, in step S4, the coarse selection time is 4-6 minutes; the fine selection I time is 3-4 minutes; the fine selection II time is 3-4 minutes; the sweep selection I time is 4-5 minutes; and the sweep selection II time is 4-5 minutes.

[0012] As a preferred embodiment of the present invention, the preparation steps of the core-shell structured metal-organic framework modified material include: A1. Dissolve 2-methylimidazole in a mixed solvent of methanol and deionized water to obtain solution A; dissolve zinc nitrate hexahydrate in a mixed solvent of methanol and deionized water to obtain solution B; place solution A in a three-necked flask, and add solution B dropwise under argon protection and continuous stirring. After the addition is complete, continue stirring to obtain a suspension; allow the suspension to crystallize at room temperature, and obtain a solid product by centrifugation; wash the solid product with methanol, and then activate it in a vacuum drying oven at 78-82℃ to obtain ZIF-8 core material; A2. Disperse the ZIF-8 core material in an aqueous acetic acid solution and sonicate to form a ZIF-8 dispersion. Dissolve chitosan in an aqueous acetic acid solution and add it to the ZIF-8 dispersion. Under argon protection and stirring, add hydroxyacrylate and glutaraldehyde to the ZIF-8 dispersion and react in a water bath at 58-62℃. After the reaction is complete, obtain the solid by centrifugation. Wash the solid with deionized water until neutral and dry it under vacuum at 48-52℃ to obtain the CS-ZIF-8 intermediate. A3. The CS-ZIF-8 intermediate was redispersed in a mixed solvent of ethanol and water and sonicated. Under continuous stirring and argon protection, triethylamine, mercaptoacetic acid, and copper chloride were added sequentially, and the reaction was carried out at 44-46℃. A mixed aqueous solution of acrylamide and N,N'-methylenebisacrylamide was added, and the reaction was continued at 58-62℃. After the reaction was completed, the solid product was obtained by centrifugation. The solid product was washed alternately with ethanol and deionized water and dried under vacuum at 58-62℃ to obtain the MOF@CS precursor. A4. Disperse the MOF@CS precursor in deionized water, add polyvinyl alcohol, and sonicate to form a dispersion; while stirring, add dropwise an aqueous solution containing sodium dodecyl sulfate and potassium persulfate, and a mixture containing hydroxyethyl methacrylate and vinyltriethoxysilane; after the addition is complete, heat to 68-72℃ for reaction; after the reaction is complete, collect the product by filtration, wash the product with deionized water, and dry it under vacuum at 48-52℃.

[0013] In this invention, the preparation reaction mechanism of the core-shell structured metal-organic framework modified material follows the principle of multi-level precise assembly and functional modification. Its core lies in constructing a composite structure with a zeolite imidazole ester framework material as the core and a multifunctional polymer as the shell. In the initial preparation stage, in a mixed solvent of methanol and deionized water, divalent zinc ions and dimethylimidazolium self-assemble through coordination to form a crystalline core material with regular nanopores. In this step, zinc ions act as metal nodes, coordinating with nitrogen atoms in the organic ligand to construct a stable three-dimensional network structure. Subsequently, by introducing a natural polymer chitosan solution and using glutaraldehyde as a crosslinking agent, a first-layer polymer network is formed on the surface of the core material. The amino and hydroxyl groups on the chitosan molecular chains not only have electrostatic attraction and hydrogen bonding with the core surface, but glutaraldehyde also causes covalent crosslinking between the molecular chains, thereby enhancing interfacial stability. Furthermore, in an ethanol-water mixture, a solution containing thiol-containing acetic acid and divalent copper ions is added to precisely anchor the metal sites. The thiol functional group possesses a strong complexing ability for copper ions, forming stable copper-sulfur coordination centers in the polymer network. These centers are designed as recognition and catalytic sites for subsequent vulcanization processes. In the final stage, under the initiation of potassium persulfate, hydroxyethyl methacrylate and monomers such as vinyltriethoxysilane undergo in-situ polymerization on the material surface, forming the outermost functionalized encapsulation shell. This shell not only enhances structural stability through siloxane hydrolysis and condensation, but its abundant ether bonds and hydroxyl groups also endow the material with responsive characteristics to the pH of the slurry. This achieves a synergistic design of core-shell materials that possess high specific surface area, ordered pores, and specific recognition sites with environmental responsiveness.

[0014] As a preferred embodiment of the present invention, in step A1, the molar ratio of 2-methylimidazole to zinc nitrate hexahydrate is (2-4):1; and the crystallization time at room temperature is 12-24h.

[0015] As a preferred embodiment of the present invention, in step A2, the mass ratio of chitosan to ZIF-8 core is 1:(1-2); the reaction time in a water bath at 58-62℃ is 6-8h.

[0016] As a preferred embodiment of the present invention, in step A3, the mass ratio of mercaptoacetic acid to CS-ZIF-8 intermediate is (1-3):(3-10); the mass ratio of triethylamine to CS-ZIF-8 intermediate is 1:(7-9); the mass ratio of copper chloride to CS-ZIF-8 intermediate is 1:(5-7); and the reaction time is 8-10 h at 44-46 °C.

[0017] As a preferred embodiment of the present invention, in step A4, the reaction time is 6-8 hours after the temperature is raised to 68-72°C.

[0018] Compared with the prior art, the present invention has the following beneficial effects: (1) This invention fundamentally solves the technical problem of low sulfiding agent efficiency in the flotation of highly alkaline copper oxide ores by introducing a specially formulated core-shell structured metal-organic framework modified material. This modified material possesses unique surface properties and a porous structure, enabling it to accurately identify the surface of copper oxide minerals in a highly alkaline environment and selectively adsorb onto them. Through the loading and slow-release effect of its internal pores on sulfiding agent molecules, the sulfidation process is controlled. Compared with the traditional ammonium salt activation method, this method increases the utilization rate of the sulfiding agent by more than 40%, while significantly reducing the total amount of sulfiding agent used, achieving satisfactory results in industrial trials. Due to the modified material's specific recognition ability of copper oxide minerals, it effectively inhibits the ineffective reaction between the sulfiding agent and calcium magnesium gangue minerals, avoiding non-selective consumption of the sulfiding agent. This significantly reduces the reagent cost of the entire flotation process and significantly improves economic benefits.

[0019] (2) This flotation method comprehensively improves the flotation indicators and process stability of copper oxide ore through the synergistic effect of multiple steps. In the pulp pretreatment stage, the combined use of modified materials and sodium carbonate creates a suitable flotation environment; the strategy of adding sulfiding agents in stages complements the slow-release characteristics of modified materials, ensuring the uniform formation and stable existence of the sulfidation film; the use of combined collectors further enhances the hydrophobicity effect of the target minerals. This multi-stage synergistic effect significantly improves the grade and recovery rate of copper concentrate. Industrial test data shows that the copper recovery rate increased by more than ten percentage points after adopting this method, and the concentrate grade was also significantly improved. At the same time, due to the supplementary addition of modified materials in the beneficiation stage, the recovery of difficult-to-benefit fine-grained copper oxide minerals is strengthened, effectively solving the technical problem of low recovery rate of fine-grained minerals, and further improving resource utilization.

[0020] (3) The technical solution of this invention demonstrates significant advantages in environmental protection and sustainable development. The preparation process of the modified material adopts an environmentally friendly methanol-water solution system, replacing the toxic and harmful organic solvents used in traditional preparation methods, thus eliminating the introduction of toxic substances at the source and conforming to the development concept of green chemistry. The modified material itself has good chemical stability and mechanical strength, and can be recovered and reused from tailings, which not only reduces material costs but also reduces the generation of solid waste. The entire flotation process does not require the addition of activators such as ammonium salts that are prone to causing environmental pollution, significantly reducing the potential harm of mineral processing wastewater to the environment. In addition, this method has good adaptability to various high-alkalinity copper oxide ores, and is particularly suitable for processing difficult-to-process copper oxide resources with high calcium and magnesium content. It provides technical support for the development of a large number of low-grade copper oxide ores that cannot be economically utilized by traditional technologies, and has important strategic resource significance and broad industrial application prospects. Detailed Implementation

[0021] To facilitate understanding of the present invention, the following embodiments are provided. Those skilled in the art should understand that these embodiments are merely illustrative and should not be construed as limiting the scope of the invention.

[0022] The sources of some components in the examples and comparative examples are as follows: The sodium carbonate was purchased from Tangshan Sanyou Chemical Co., Ltd.

[0023] The sodium sulfide was purchased from Inner Mongolia Yabulai Salt Chemical Group Co., Ltd.

[0024] The butyl xanthate was purchased from Anshan Fengxiang Fine Chemical Co., Ltd.

[0025] The benzohydroxyoxime acid was purchased from Yantai Hengxin Chemical Technology Co., Ltd.

[0026] The pine oil was purchased from Zhuzhou Mineral Processing Reagents Co., Ltd.

[0027] The flotation machine was purchased from Yantai Xinhai Mining Machinery Co., Ltd.

[0028] The 2-methylimidazole was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0029] The zinc nitrate hexahydrate was purchased from Sinopharm Chemical Reagent Co., Ltd.

[0030] The triethylamine was purchased from Jiangsu Yangnong Chemical Group Co., Ltd.

[0031] The thioglycolic acid was purchased from Zhejiang Xin'an Chemical Group Co., Ltd.

[0032] The copper chloride was purchased from Shanghai Maclean Biochemical Technology Co., Ltd.

[0033] The acrylamide was purchased from Shandong Baomo Biochemical Co., Ltd.

[0034] The N,N'-methylenebisacrylamide was purchased from Jiangsu Tianchen New Material Co., Ltd.

[0035] The sodium dodecyl sulfate was purchased from Guangzhou Langqi Industrial Co., Ltd.

[0036] The potassium persulfate was purchased from Tianjin Bodi Chemical Co., Ltd.

[0037] The hydroxyethyl methacrylate was purchased from Jiangsu Sanmu Group Co., Ltd.

[0038] The vinyltriethoxysilane was purchased from Guangzhou Jucheng Technology Co., Ltd.

[0039] Example 1 This embodiment provides a flotation method for highly alkaline copper oxide ores that avoids runaway sulfidation activation. Preparation of core-shell structured metal-organic framework modified materials: First, 3.28 g of 2-methylimidazole was dissolved in 60 mL of a 2:1 mixture of methanol and deionized water to obtain solution A; 3.72 g of zinc nitrate hexahydrate was dissolved in 40 mL of a 2:1 mixture of methanol and deionized water to obtain solution B; Solution A was placed in a 250 mL three-necked flask, and under argon protection and continuous stirring at 500 r / min, solution B was added dropwise at a rate of 60 drops / min using a constant pressure dropping funnel. After the addition was complete, stirring was continued for 30 min to obtain a suspension; The suspension was allowed to crystallize at 25℃ for 18 h, and the solid product was obtained by centrifugation; The solid product was washed three times with methanol and activated in a vacuum drying oven at 80℃ for 8 h to obtain the ZIF-8 core material. In the second step, 1.0 g of the ZIF-8 core material prepared in the first step was dispersed in 100 mL of 2% acetic acid aqueous solution and ultrasonically treated for 30 min to form a ZIF-8 dispersion. 0.5 g of chitosan was dissolved in 50 mL of 1% acetic acid aqueous solution and stirred until completely dissolved before being added to the ZIF-8 dispersion. Under argon protection and stirring at 400 r / min, 0.2 g of hydroxyacrylate and 0.05 g of glutaraldehyde were added, and the mixture was reacted in a 60℃ water bath for 7 h. After the reaction was completed, the solid was obtained by centrifugation. The solid was washed with deionized water until neutral and dried under vacuum at 50℃ for 6 h to obtain the CS-ZIF-8 intermediate. In the third step, 0.8 g of the CS-ZIF-8 intermediate prepared in the second step was redispersed in 150 mL of a 2:1 volume ratio of ethanol and deionized water and sonicated for 20 min. Under continuous stirring and argon protection, 0.1 g of triethylamine, 0.3 g of mercaptoacetic acid, and 0.15 g of copper chloride were added sequentially, and the reaction was carried out at 45 °C for 9 h. Then, 20 mL of an aqueous solution of 0.2 g of acrylamide and 0.05 g of N,N'-methylenebisacrylamide was added, and the reaction was continued at 60 °C for 4 h. After the reaction was completed, the solid product was obtained by centrifugation. The solid product was washed three times alternately with ethanol and deionized water and dried under vacuum at 60 °C for 6 h to obtain the MOF@CS precursor.In the fourth step, 0.5 g of the MOF@CS precursor obtained in the third step was uniformly dispersed in 100 mL of deionized water, and 0.1 g of polyvinyl alcohol was added. The mixture was ultrasonically treated for 30 min to form a dispersion. Under stirring at 300 r / min, 20 mL of an aqueous solution containing 0.2 g of sodium dodecyl sulfate and 0.1 g of potassium persulfate, as well as a mixture containing 0.3 g of hydroxyethyl methacrylate and 0.1 g of vinyltriethoxysilane, were added dropwise, with the addition rate controlled to be completed within 1 h. After the addition was completed, the temperature was raised to 70 °C and the reaction was carried out for 7 h. After the reaction was completed, the product was collected by filtration, washed with deionized water, and dried under vacuum at 50 °C for 12 h to obtain the MOF@CS-HA modified material.

[0040] Flotation steps for high-alkalinity copper oxide ore to avoid runaway sulfidation activation: First, crush and grind 500 g of high-alkalinity copper oxide ore to a particle size of -0.074 mm (80%), preparing a 35% concentration slurry (1429 g). Under stirring at 1300 r / min, add 0.1 g of core-shell structured metal-organic framework modifier and 0.5 g of sodium carbonate to adjust the slurry pH to 9.2. Second, add sodium sulfide to the slurry, totaling 1.1 g. Add 0.44 g of sodium sulfide first, then add 0.66 g after a 4-minute interval, stirring at 900 r / min for 14 minutes. Third, add a combined collector to the slurry, including 0.06 g of butyl xanthate and 0.02 g of benzoyl hydroxamic acid, stirring for 4 minutes; then add 0.03 g of pine oil, stirring for 2 minutes. The fourth step involves starting the flotation machine's aeration system and controlling the aeration rate at 0.2 m³ / m²·min for flotation separation. The roughing time is 5 min, the cleaning time (I) is 3.5 min, the cleaning time (II) is 3.5 min, the scavenging time (I) is 4.5 min, and the scavenging time (II) is 4.5 min. During the cleaning stage, 0.04 g of core-shell structured metal-organic framework modified material is added to the slurry. After flotation, the enriched copper concentrate is filtered and dried. The core-shell structured metal-organic framework modified material is recovered and regenerated from the tailings.

[0041] Example 2 This embodiment provides a flotation method for highly alkaline copper oxide ores that avoids runaway sulfidation activation. Preparation of core-shell structured metal-organic framework modified materials: First, 2.46 g of 2-methylimidazole is dissolved in 60 mL of a 2:1 mixture of methanol and deionized water to obtain solution A; 3.72 g of zinc nitrate hexahydrate is dissolved in 40 mL of a 2:1 mixture of methanol and deionized water to obtain solution B; Solution A is placed in a 250 mL three-necked flask, and under argon protection and continuous stirring at 500 r / min, solution B is added dropwise at a rate of 60 drops / min using a constant pressure dropping funnel. After the addition is complete, stirring continues for 30 min to obtain a suspension; The suspension is allowed to crystallize at 25℃ for 18 h, and the solid product is obtained by centrifugation; The solid product is washed three times with methanol and activated in a vacuum drying oven at 80℃ for 8 h to obtain the ZIF-8 core material. In the second step, 0.8 g of the ZIF-8 core material prepared in the first step was dispersed in 100 mL of 2% acetic acid aqueous solution and ultrasonically treated for 30 min to form a ZIF-8 dispersion. 0.4 g of chitosan was dissolved in 50 mL of 1% acetic acid aqueous solution and stirred until completely dissolved before being added to the ZIF-8 dispersion. Under argon protection and stirring at 400 r / min, 0.2 g of hydroxyacrylate and 0.05 g of glutaraldehyde were added, and the mixture was reacted in a 60℃ water bath for 7 h. After the reaction was completed, the solid was obtained by centrifugation. The solid was washed with deionized water until neutral and dried under vacuum at 50℃ for 6 h to obtain the CS-ZIF-8 intermediate. In the third step, 0.7 g of the CS-ZIF-8 intermediate prepared in the second step was redispersed in 150 mL of a 2:1 volume ratio of ethanol and deionized water and sonicated for 20 min. Under continuous stirring and argon protection, 0.1 g of triethylamine, 0.2 g of mercaptoacetic acid, and 0.1 g of copper chloride were added sequentially, and the reaction was carried out at 45 °C for 9 h. Then, 20 mL of an aqueous solution of 0.2 g of acrylamide and 0.05 g of N,N'-methylenebisacrylamide was added, and the reaction was continued at 60 °C for 4 h. After the reaction was completed, the solid product was obtained by centrifugation. The solid product was washed three times alternately with ethanol and deionized water and dried under vacuum at 60 °C for 6 h to obtain the MOF@CS precursor.In the fourth step, 0.4 g of the MOF@CS precursor obtained in the third step was uniformly dispersed in 100 mL of deionized water, and 0.1 g of polyvinyl alcohol was added. The mixture was ultrasonically treated for 30 min to form a dispersion. Under stirring at 300 r / min, 20 mL of an aqueous solution containing 0.2 g of sodium dodecyl sulfate and 0.1 g of potassium persulfate, as well as a mixture containing 0.2 g of hydroxyethyl methacrylate and 0.08 g of vinyltriethoxysilane, were added dropwise, with the addition rate controlled to be completed within 1 h. After the addition was completed, the temperature was raised to 70 °C and the reaction was carried out for 7 h. After the reaction was completed, the product was collected by filtration, washed with deionized water, and dried under vacuum at 50 °C for 12 h to obtain the MOF@CS-HA modified material.

[0042] Flotation steps for high-alkalinity copper oxide ore to avoid runaway sulfidation activation: First, crush and grind 500 g of high-alkalinity copper oxide ore to a particle size of -0.074 mm (80%), preparing 1515 g of a 33% concentration slurry. Under stirring at 1300 r / min, add 0.09 g of core-shell structured metal-organic framework modifier and 0.6 g of sodium carbonate to adjust the slurry pH to 9.0. Second, add sodium sulfide to the slurry, totaling 1.3 g. Add 0.52 g of sodium sulfide first, then add 0.78 g after a 4-minute interval, stirring at 800 r / min for 12 minutes. Third, add a combined collector to the slurry, including 0.05 g of butyl xanthate and 0.017 g of benzoyl hydroxyxamic acid, stirring for 3 minutes; then add 0.02 g of pine oil, stirring for 2 minutes. The fourth step involves starting the flotation machine's aeration system and controlling the aeration rate at 0.2 m³ / m²·min for flotation separation. The roughing time is 4 min, the cleaning time (I) is 3 min, the cleaning time (II) is 3 min, the scavenging time (I) is 4 min, and the scavenging time (II) is 4 min. During the cleaning stage, 0.03 g of core-shell structured metal-organic framework modified material is added to the slurry. After flotation, the enriched copper concentrate is filtered and dried. The core-shell structured metal-organic framework modified material is recovered and regenerated from the tailings.

[0043] Example 3 This embodiment provides a flotation method for highly alkaline copper oxide ores that avoids runaway sulfidation activation. Preparation of core-shell structured metal-organic framework modified materials: First, 3.69 g of 2-methylimidazole was dissolved in 60 mL of a 2:1 mixture of methanol and deionized water to obtain solution A; 3.72 g of zinc nitrate hexahydrate was dissolved in 40 mL of a 2:1 mixture of methanol and deionized water to obtain solution B; Solution A was placed in a 250 mL three-necked flask, and under argon protection and continuous stirring at 500 r / min, solution B was added dropwise at a rate of 60 drops / min using a constant pressure dropping funnel. After the addition was complete, stirring was continued for 30 min to obtain a suspension; The suspension was allowed to crystallize at 25℃ for 18 h, and the solid product was obtained by centrifugation; The solid product was washed three times with methanol and activated in a vacuum drying oven at 80℃ for 8 h to obtain the ZIF-8 core material. In the second step, 1.2 g of the ZIF-8 core material prepared in the first step was dispersed in 100 mL of 2% acetic acid aqueous solution and ultrasonically treated for 30 min to form a ZIF-8 dispersion. 0.6 g of chitosan was dissolved in 50 mL of 1% acetic acid aqueous solution and stirred until completely dissolved before being added to the ZIF-8 dispersion. Under argon protection and stirring at 400 r / min, 0.2 g of hydroxyacrylate and 0.05 g of glutaraldehyde were added, and the mixture was reacted in a 60℃ water bath for 7 h. After the reaction was completed, the solid was obtained by centrifugation. The solid was washed with deionized water until neutral and dried under vacuum at 50℃ for 6 h to obtain the CS-ZIF-8 intermediate. In the third step, 0.9 g of the CS-ZIF-8 intermediate prepared in the second step was redispersed in 150 mL of a 2:1 volume ratio of ethanol and deionized water and sonicated for 20 min. Under continuous stirring and argon protection, 0.1 g of triethylamine, 0.3 g of mercaptoacetic acid, and 0.18 g of copper chloride were added sequentially, and the reaction was carried out at 45 °C for 9 h. Then, 20 mL of an aqueous solution of 0.2 g of acrylamide and 0.05 g of N,N'-methylenebisacrylamide was added, and the reaction was continued at 60 °C for 4 h. After the reaction was completed, the solid product was obtained by centrifugation. The solid product was washed three times alternately with ethanol and deionized water and dried under vacuum at 60 °C for 6 h to obtain the MOF@CS precursor.In the fourth step, 0.6 g of the MOF@CS precursor obtained in the third step was uniformly dispersed in 100 mL of deionized water, and 0.1 g of polyvinyl alcohol was added. The mixture was ultrasonically treated for 30 min to form a dispersion. Under stirring at 300 r / min, 20 mL of an aqueous solution containing 0.2 g of sodium dodecyl sulfate and 0.1 g of potassium persulfate, as well as a mixture containing 0.25 g of hydroxyethyl methacrylate and 0.12 g of vinyltriethoxysilane, were added dropwise, with the addition rate controlled to be completed within 1 h. After the addition was completed, the temperature was raised to 70 °C and the reaction was carried out for 7 h. After the reaction was completed, the product was collected by filtration, washed with deionized water, and dried under vacuum at 50 °C for 12 h to obtain the MOF@CS-HA modified material.

[0044] Flotation steps for high-alkalinity copper oxide ore to avoid runaway sulfidation activation: First, crush and grind 500 g of high-alkalinity copper oxide ore to a particle size of -0.074 mm (80%), preparing a 38% concentration slurry (1316 g). Under stirring at 1300 r / min, add 0.12 g of core-shell structured metal-organic framework modifier and 0.7 g of sodium carbonate to adjust the slurry pH to 9.5. Second, add sodium sulfide to the slurry, totaling 1.5 g. Add 0.45 g of sodium sulfide first, then add 1.05 g after a 5-minute interval, stirring at 1000 r / min for 15 minutes. Third, add a combined collector to the slurry, including 0.075 g of butyl xanthate and 0.025 g of benzoyl hydroxamic acid, stirring for 5 minutes; then add 0.04 g of pine oil, stirring for 2 minutes. The fourth step involves starting the flotation machine's aeration system and controlling the aeration rate at 0.2 m³ / m²·min for flotation separation. The roughing time is 6 min, the cleaning time (I) is 4 min, the cleaning time (II) is 4 min, the scavenging time (I) is 5 min, and the scavenging time (II) is 5 min. During the cleaning stage, 0.05 g of core-shell structured metal-organic framework modified material is added to the slurry. After flotation, the enriched copper concentrate is filtered and dried. The core-shell structured metal-organic framework modified material is recovered and regenerated from the tailings.

[0045] Comparative Example 1 The difference between this comparative example and Example 1 lies in the flotation steps for high-alkaline copper oxide ore to avoid runaway sulfide activation: First, 500 g of high-alkaline copper oxide ore is crushed and ground to a particle size of -0.074 mm (80%), preparing 1429 g of a 35% concentration pulp. Under stirring at 1300 r / min, 0.5 g of sodium carbonate is added to the pulp to adjust the pH to 9.2. Second, 1.1 g of sodium sulfide is added to the pulp all at once, and stirring is carried out at 900 r / min for 14 min. Third, a combined collector is added to the pulp, consisting of 0.06 g of butyl xanthate and 0.02 g of benzoyl hydroxamic acid, and stirring is carried out for 4 min. Then, 0.03 g of pine oil is added and stirring is carried out for 2 min. Fourth, the flotation machine aeration system is turned on, controlling the aeration rate at 0.2 m³ / m²·min, for flotation separation. The roughing time is 5 min, and the cleaning time (I) is 3.5 min. The flotation time is 3.5 min for the second stage of selection, 4.5 min for the first stage of scavenging, and 4.5 min for the second stage of scavenging. After flotation, the enriched copper concentrate is filtered and dried.

[0046] Comparative Example 2 The difference between this comparative example and Example 1 lies in the preparation of the core-shell structured metal-organic framework modified material: First, 3.28 g of 2-methylimidazole was dissolved in 60 mL of a 2:1 mixture of methanol and deionized water to obtain solution A; 3.72 g of zinc nitrate hexahydrate was dissolved in 40 mL of a 2:1 mixture of methanol and deionized water to obtain solution B; Solution A was placed in a 250 mL three-necked flask, and under argon protection and continuous stirring at 500 r / min, solution B was added dropwise at a rate of 60 drops / min using a constant pressure dropping funnel. After the addition was complete, stirring was continued for 30 min to obtain a suspension; The suspension was allowed to crystallize at room temperature (25°C) for 18 h, and the solid product was obtained by centrifugation; The solid product was washed three times with methanol and activated in a vacuum drying oven at 80°C for 8 h to obtain the ZIF-8 core material.

[0047] Flotation steps for high-alkalinity copper oxide ore to avoid uncontrolled sulfidation activation: First, crush and grind 500 g of high-alkalinity copper oxide ore to a particle size of -0.074 mm (80%), preparing 1429 g of a 35% concentration slurry. Under stirring at 1300 r / min, add 0.1 g of ZIF-8 core material and 0.5 g of sodium carbonate to the slurry, adjusting the pH to 9.2. Second, add sodium sulfide to the slurry, a total of 1.1 g. Add 0.44 g of sodium sulfide first, then add 0.66 g after a 4-minute interval, stirring at 900 r / min for 14 minutes. Third, add a combined collector to the slurry, including 0.06 g of butyl xanthate and 0.02 g of benzoyl hydroxamic acid, stirring for 4 minutes; then add 0.03 g of pine oil, stirring for 2 minutes. Fourth, turn on the flotation machine's aeration system, controlling the aeration rate to 0.2 g. The flotation separation was carried out at a rate of m³ / m²·min; the roughing time was 5 min, the cleaning time I was 3.5 min, the cleaning time II was 3.5 min, the scavenging time I was 4.5 min, and the scavenging time II was 4.5 min; during the cleaning stage, 0.04 g of ZIF-8 core material was added to the slurry; after flotation, the enriched copper concentrate was filtered and dried; the ZIF-8 core material was recovered and regenerated from the tailings.

[0048] Comparative Example 3 The difference between this comparative example and Example 1 lies in the preparation of the core-shell structured metal-organic framework modified material: First, 3.28 g of 2-methylimidazole was dissolved in 60 mL of a 2:1 mixture of methanol and deionized water to obtain solution A; 3.72 g of zinc nitrate hexahydrate was dissolved in 40 mL of a 2:1 mixture of methanol and deionized water to obtain solution B; Solution A was placed in a 250 mL three-necked flask, and under argon protection and continuous stirring at 500 r / min, solution B was added dropwise at a rate of 60 drops / min using a constant pressure dropping funnel. After the addition was complete, stirring was continued for 30 min to obtain a suspension; The suspension was allowed to crystallize at room temperature (25°C) for 18 h, and the solid product was obtained by centrifugation; The solid product was washed three times with methanol and activated in a vacuum drying oven at 80°C for 8 h to obtain the ZIF-8 core material. In the second step, 1.0 g of the ZIF-8 core material prepared in the first step was dispersed in 100 mL of 2% acetic acid aqueous solution and ultrasonically treated for 30 min to form a ZIF-8 dispersion. 0.5 g of chitosan was dissolved in 50 mL of 1% acetic acid aqueous solution and stirred until completely dissolved before being added to the ZIF-8 dispersion. Under argon protection and stirring at 400 r / min, 0.2 g of hydroxyacrylate and 0.05 g of glutaraldehyde were added, and the mixture was reacted in a 60℃ water bath for 7 h. After the reaction was completed, the solid was obtained by centrifugation. The solid was washed with deionized water until neutral and dried under vacuum at 50℃ for 6 h to obtain the CS-ZIF-8 intermediate. In the third step, 0.8 g of the CS-ZIF-8 intermediate prepared in the second step was redispersed in 150 mL of a mixed solvent of ethanol and deionized water with a volume ratio of 2:1, and sonicated for 20 min. Under continuous stirring and argon protection, 0.1 g of triethylamine was added, followed by 20 mL of an aqueous solution of 0.2 g of acrylamide and 0.05 g of N,N'-methylenebisacrylamide. The reaction was continued at 60 °C for 4 h. After the reaction was completed, the solid product was obtained by centrifugation. The solid product was washed three times alternately with ethanol and deionized water, and dried under vacuum at 60 °C for 6 h to obtain the MOF@CS precursor with copper-deficient sites.In the fourth step, 0.5 g of the MOF@CS precursor obtained in the third step was uniformly dispersed in 100 mL of deionized water, and 0.1 g of polyvinyl alcohol was added. The mixture was ultrasonically treated for 30 min to form a dispersion. Under stirring at 300 r / min, 20 mL of aqueous solution containing 0.2 g of sodium dodecyl sulfate and 0.1 g of potassium persulfate, as well as a mixture containing 0.3 g of hydroxyethyl methacrylate and 0.1 g of vinyltriethoxysilane, were added dropwise, with the addition rate controlled to be completed within 1 h. After the addition was completed, the temperature was raised to 70 °C and the reaction was carried out for 7 h. After the reaction was completed, the product was collected by filtration, washed with deionized water, and dried under vacuum at 50 °C for 12 h to obtain the MOF@CS-HA modified material with copper-deficient sites.

[0049] Flotation steps for high-alkalinity copper oxide ore to avoid runaway sulfidation activation: First, crush and grind 500 g of high-alkalinity copper oxide ore to a particle size of -0.074 mm (80%), preparing 1429 g of a 35% concentration slurry. Under stirring at 1300 r / min, add 0.1 g of MOF@CS-HA modifier with copper-deficient sites and 0.5 g of sodium carbonate to adjust the slurry pH to 9.2. Second, add sodium sulfide to the slurry, totaling 1.1 g. First add 0.44 g of sodium sulfide, then add 0.66 g after a 4-minute interval, stirring at 900 r / min for 14 minutes. Third, add a combined collector to the slurry, including 0.06 g of butyl xanthate and 0.02 g of benzoyl hydroxamic acid, stirring for 4 minutes; then add 0.03 g of pine oil, stirring for 2 minutes. The fourth step involves starting the flotation machine's aeration system and controlling the aeration rate at 0.2 m³ / m²·min for flotation separation. The roughing time is 5 min, the cleaning time (I) is 3.5 min, the cleaning time (II) is 3.5 min, the scavenging time (I) is 4.5 min, and the scavenging time (II) is 4.5 min. During the cleaning stage, 0.04 g of MOF@CS-HA modified material with copper-deficient sites is added to the slurry. After flotation, the enriched copper concentrate is filtered and dried. The MOF@CS-HA modified material with copper-deficient sites is recovered and regenerated from the tailings.

[0050] In accordance with national and industry standard testing specifications, the performance of the flotation methods for avoiding runaway sulfide activation in the above embodiments and comparative examples was tested. The testing methods are as follows: Performance testing was conducted according to standard flotation experimental procedures. All tests were completed in a constant temperature laboratory environment of 25±1℃. The testing process strictly followed the following steps: First, 500 g of high-alkalinity copper oxide ore was crushed to -2 mm using a standard jaw crusher and roller mill. Then, it was ground to -0.074 mm (80%) using a laboratory rod mill. Flotation experiments were then conducted in a 1.5L single-cell flotation machine according to the specific formulations and process conditions described in each embodiment and comparative example. The pH value of the pulp was monitored and recorded in real time using a precision pH meter with an accuracy of ±0.02. All reagents were weighed using an electronic balance with an accuracy of ±0.001. g; During the flotation process, all operating parameters, including pulp pH, reagent dosage and order, stirring intensity, and reaction time, were recorded in detail; After flotation, copper concentrate and tailings products were collected separately, vacuum filtered using a Buchner funnel, and then dried to constant weight in a 105℃ constant temperature drying oven. The weight of each product was measured using an electronic balance with an accuracy of ±0.01 g; The flotation process was carried out using a PerkinElmer PinAAcle (USA) balance. The copper content in the raw ore, concentrate, and tailings was determined using a 900T atomic absorption spectrometer. Each sample was measured three times in parallel, and the average value was taken. The instrument's detection limit was 0.01 μg / mL, and the relative standard deviation was less than 1%. Based on the mass balance principle, the copper recovery rate, concentrate grade, and enrichment ratio were accurately calculated, while the actual consumption of sodium sulfide was accurately recorded. To verify the reliability of the experimental results, each example and comparative example was conducted three independent replicates under identical conditions. The final data was the average of the three experiments, and the standard deviation was calculated. The relative standard deviation of all data was controlled within 2% to ensure data reproducibility and statistical reliability. The flotation rate constant was obtained by tracking the flotation product recovery rate at different time points and fitting it using a first-order kinetic model. The selectivity index was calculated based on the ratio of copper recovery rate to gangue mineral recovery rate and was used to evaluate the selective separation effect of the flotation process.

[0051] The performance test data above are shown in Table 1.

[0052] Table 1 Performance Test Results As can be seen from the above, Examples 1-3 comprehensively and significantly solved the core technical problem of uncontrolled sulfidation activation during the flotation process of highly alkaline copper oxide ores, which this invention aims to overcome. The copper recovery rates of Examples 1-3 reached 85.7%, 83.2%, and 82.9%, respectively, far exceeding the 71.3% of Comparative Example 1. This fully demonstrates that the modified material, through its specific recognition and directional release function, effectively promoted the formation of a stable sulfide film and significantly improved the recovery efficiency of the target mineral. Regarding concentrate grade, Examples 1-3 obtained high-quality concentrates of 21.4-20.5%, significantly better than the 18.4% of Comparative Example 1, indicating that the modified material significantly enhanced the selectivity of the flotation process and effectively suppressed the inclusion of gangue minerals. The most significant effect is reflected in the amount of sodium sulfide used. Example 1 achieved excellent flotation performance with only 1.10 g of sodium sulfide, while Comparative Example 1, even with a higher dosage of 2.20 g, still showed unsatisfactory results. This directly confirms that the modified material, through precise control of the sulfidation process, successfully blocked the ineffective side reaction between the sulfiding agent and alkaline gangue, increasing the utilization rate of the sulfiding agent by approximately 50%. Comparative Example 2, using only unmodified ZIF-8 core material, achieved a copper recovery rate of 76.5% and a concentrate grade of 19.2%, which, while better than Comparative Example 1, was significantly inferior to the example. This demonstrates that a complete core-shell structure design and surface functionalization modification are indispensable for achieving efficient sulfidation control. Comparative Example 3, using a modified material lacking copper recognition sites, achieved a copper recovery rate of 74.8% and a concentrate grade of 18.9%, with results between Comparative Example 2 and the example. This proves that the copper recognition sites in the material are a key factor in achieving specific binding with the surface of copper oxide minerals and improving sulfidation efficiency. Furthermore, Examples 1-3 showed enrichment ratios of 9.95-9.53 and flotation rate constants of 0.152-0.143 min⁻¹. -1 The results showed that the composite material significantly outperformed all comparative samples in terms of comprehensive evaluation indicators such as selectivity index (5.42-5.06), fully demonstrating that the present invention, through core-shell structured metal-organic framework modification of materials, successfully achieved precise control of the sulfidation flotation process of copper oxide ore under high alkalinity environment. This effectively solved the three major technical bottlenecks of high ineffective consumption of sulfiding agent, poor stability of sulfidation film, and low flotation selectivity, providing a reliable technical solution for the efficient utilization of similar difficult-to-process copper oxide ore.

Claims

1. A high alkaline copper oxide ore flotation process avoiding runaway sulphidisation activation, characterised in that, The method comprises the following steps: S1, high-alkaline copper oxide ore is crushed and ground to prepare a slurry; under stirring, a core-shell metal organic framework modifier is added into the slurry, and sodium carbonate is added to adjust the pH value of the slurry to 9.0-9.5; S2, sodium sulfide is added into the slurry and stirred; the sodium sulfide is added in two times, 30-40% of the total amount of sodium sulfide is added first, and 60-70% of the total amount of sodium sulfide is added after 3-5 minutes; S3, a combined collector is added into the slurry, the combined collector is a mixture of butyl xanthate and benzohydroxamic acid; then, pine oil is added and stirred; S4, the aeration system of the flotation machine is started, and flotation separation is performed; the foam rich in copper minerals is scraped out by a scraper and enters a concentrate collection tank; the gangue minerals remain in the tank and are discharged as tailings; The flotation process adopts a closed-circuit process of roughing, cleaning I and cleaning II, scavenging I and scavenging II; in the cleaning stage, the core-shell metal organic framework modifier is added into the slurry; After the flotation, the enriched copper concentrate is filtered and dried; the core-shell metal organic framework modifier is recovered and regenerated from the tailings.

2. The high base copper oxide ore flotation process to avoid runaway sulphidisation activation according to claim 1, characterised in that, In step S1, the concentration of the slurry is 30-40%; the stirring time is 10-15 minutes.

3. The high base copper oxide ore flotation process to avoid runaway sulphidisation activation according to claim 1, characterised in that, In step S2, the stirring speed is 800-1000 rpm.

4. The high base copper oxide ore flotation process to avoid runaway sulphidisation activation according to claim 1, characterised in that, In step S3, the mass ratio of butyl xanthate to benzohydroxamic acid is 3:

1.

5. The high base copper oxide ore flotation process to avoid runaway sulphidisation activation according to claim 1, characterised in that, In step S4, the time for roughing is 4-6 minutes; the time for cleaning I is 3-4 minutes, the time for cleaning II is 3-4 minutes; the time for scavenging I is 4-5 minutes, and the time for scavenging II is 4-5 minutes.

6. The high base copper oxide ore flotation process to avoid runaway sulphidisation activation according to any one of claims 1 to 5 characterised by, The preparation steps of the core-shell metal organic framework modifier include: A1, 2-methyl imidazole is dissolved in a mixed solvent of methanol and deionized water to obtain solution A; zinc nitrate hexahydrate is dissolved in a mixed solvent of methanol and deionized water to obtain solution B; solution A is placed in a three-necked flask, solution B is added dropwise under the conditions of argon protection and continuous stirring, and after the dropwise addition is completed, stirring is continued to obtain a suspension; the suspension is left to stand at room temperature for crystallization, and a solid product is obtained by centrifugal separation; the solid product is washed with methanol and then activated in a vacuum drying box at 78-82°C to obtain ZIF-8 core material; A2, the ZIF-8 core material is dispersed in an aqueous acetic acid solution and ultrasonically treated to form a ZIF-8 dispersion; chitosan is dissolved in an aqueous acetic acid solution and added to the ZIF-8 dispersion; under argon protection and stirring, hydroxy acrylate and glutaraldehyde are added to the ZIF-8 dispersion and reacted in a water bath at 58-62°C; after the reaction is completed, a solid is obtained by centrifugal separation, the solid is washed with deionized water until it is neutral, and then dried under vacuum at 48-52°C to obtain a CS-ZIF-8 intermediate; A3, the CS-ZIF-8 intermediate is redispersed in a mixed solvent of ethanol and water and ultrasonically treated; under continuous stirring and argon protection, triethylamine, mercaptoacetic acid and copper chloride are sequentially added, and the reaction is carried out at 44-46℃; a mixed aqueous solution of acrylamide and N,N'-methylene bisacrylamide is added, and the reaction is continued at 58-62℃; after the reaction is completed, the solid product is obtained by centrifugal separation, the solid product is washed with ethanol and deionized water alternately, and dried under vacuum at 58-62℃ to obtain a MOF@CS precursor; A4, the MOF@CS precursor is dispersed in deionized water, polyvinyl alcohol is added, and ultrasonic treatment is performed to form a dispersion; under stirring, an aqueous solution containing sodium dodecyl sulfate and potassium persulfate, and a mixture containing hydroxyethyl methacrylate and vinyltriethoxysilane are added dropwise; after the dropwise addition is completed, the temperature is raised to 68-72℃ for reaction; after the reaction is completed, the product is collected by filtration, the product is washed with deionized water, and dried under vacuum at 48-52℃.

7. The high base copper oxide ore flotation process to avoid runaway sulphidisation activation according to claim 6, characterised in that, In step A1, the molar ratio of 2-methylimidazole to zinc nitrate hexahydrate is (2-4):1; the crystallization time at room temperature is 12-24h.

8. The high base copper oxide ore flotation process to avoid runaway sulphidisation activation according to claim 6, characterised in that, In step A2, the mass ratio of chitosan to ZIF-8 core is 1:(1-2); the reaction time in a 58-62℃ water bath is 6-8h.

9. The high base copper oxide ore flotation process to avoid runaway sulphidisation activation according to claim 6, characterised in that, In step A3, the mass ratio of mercaptoacetic acid to CS-ZIF-8 intermediate is (1-3):(3-10); the mass ratio of triethylamine to CS-ZIF-8 intermediate is 1:(7-9); the mass ratio of copper chloride to CS-ZIF-8 intermediate is 1:(5-7); the reaction time at 44-46℃ is 8-10h.

10. The high base copper oxide ore flotation process to avoid runaway sulphidisation activation according to claim 6, characterised in that, In step A4, the reaction time at 68-72℃ is 6-8h.

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