Leaching method for enhanced catalytic bonding of copper ore

Abstract

The invention discloses a leaching method for enhanced catalysis of bound copper ore, and relates to the technical field of copper ore leaching, the method comprises the following steps: carrying out wet ball milling on bound copper ore to 200 meshes, and adjusting the ore pulp concentration to 40%; under the stirring state, 10m < 3 > / h oxygen-enriched air is introduced through a Roots blower, a biomass particle steam generator is adopted for heating to 70 DEG C, and citric acid with the mass being 3% of the mass of the ore is added for enhanced catalytic pretreatment for 1.5 hours; then adding a sulfuric acid leaching agent with the concentration of 10%, and leaching for 3.5 hours, wherein the total process time is 5 hours; and after filter pressing separation, leaching liquid is replaced with iron powder with the purity being larger than or equal to 98% to generate spongy copper with the grade being larger than or equal to 85%, and after tailings are discharged in a dry mode, lime is added to adjust the pH to 7 for brick making. According to the method, through the synergistic effect of fine grinding, organic acid catalysis and oxygen-enriched heating, efficient dissolution of iron and manganese inclusion and copper mineral monomer dissociation are achieved, the copper leaching recovery rate is increased to 95% or above, the process is mild, reagents are cheap, operation is easy, tailings can be recycled, economical efficiency and environment friendliness are both considered, and the method is suitable for large-scale industrial application.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of copper ore hydrometallurgical leaching, in particular to a method for enhanced catalytic leaching of combined copper ore, which is especially suitable for efficient recovery and utilization of combined copper ore resources in which copper minerals are wrapped by iron and manganese minerals. BACKGROUND

[0002] Combined copper ore is one of the important types of copper ore resources in China, and its significant feature is that copper minerals are mostly distributed in the form of fine particles (particle size is often less than 10 μm) and are tightly wrapped by a large amount of iron and manganese minerals (such as hematite and pyrolusite), forming a complex inclusion structure. This type of ore accounts for more than 30% of the proven copper ore reserves in China, and is particularly common in major copper-producing areas such as Shandong, Jiangxi and Yunnan. Due to the lower cost of early exploration and development, it has become one of the core objects of current copper mining. At present, the existing technology for leaching combined copper ore mostly uses direct sulfuric acid leaching process. However, due to the physical barrier and chemical inertia of iron and manganese inclusions, the leaching agent (sulfuric acid) can only act on a small amount of free copper on the surface of the ore, and it is difficult to penetrate to the inside and effectively contact with the combined copper minerals, resulting in a very low leaching recovery rate of copper, usually only 42%-45%. A large amount of high-value copper resources are wasted in the tailings, causing a serious lack of resource utilization.

[0003] To improve this situation, some mines have tried to improve the leaching effect by increasing the concentration of sulfuric acid (such as increasing to more than 15%) or using high temperature and high pressure conditions (temperature above 120℃, pressure above 0.8MPa). However, this scheme not only significantly increases the risk of equipment corrosion, which requires the use of special corrosion-resistant alloy equipment, resulting in an increase in initial investment cost of more than 30%, but also significantly increases energy consumption and reagent consumption, while causing new technical problems: under high temperature and high pressure conditions, iron and manganese minerals in the ore will be dissolved in large quantities at the same time, causing a sharp increase in the concentration of iron and manganese ions in the leaching solution. A large amount of neutralizing agent (such as lime) and purification agent need to be additionally invested to remove impurities, further increasing production costs. In addition, the high-concentration acidic leaching solution needs to be treated by multiple stages of neutralization before discharge, and the treated wastewater has high salt content, making it difficult to reuse and causing significant environmental pressure.

[0004] Furthermore, existing processes for treating tailings after leaching are relatively crude, often involving open-air stockpiling. Since the tailings still contain 0.3%-0.5% unleached copper and a large amount of iron and manganese minerals, long-term stockpiling not only occupies valuable land resources (approximately 1.2 acres of land are needed for every 10,000 tons of tailings), but also risks rainwater leaching causing heavy metal ions (copper, manganese, etc.) to seep into the soil and groundwater, leading to regional environmental pollution. This is seriously inconsistent with the national "zero-waste mine" construction and green metallurgical development concepts. With the continued growth of global copper demand and the increasing depletion of high-grade, easily processed copper ore resources, the urgency of developing and utilizing low-grade, complex-structured copper ore is becoming increasingly apparent. The low recovery rate, high cost, and high pollution of existing processes have become the core bottleneck restricting the efficient conversion of such resources. Developing a targeted, high-recovery, economical, and environmentally friendly copper ore leaching technology has become a key issue urgently needing to be addressed in this field. Summary of the Invention

[0005] The purpose of this invention is to overcome the low recovery rate in existing copper ore leaching processes and to provide a copper ore leaching method based on organic acid-enhanced catalytic pretreatment and synergistic oxygen enrichment and sulfuric acid leaching. By specifically dissolving iron and manganese inclusions, the copper minerals are fully exposed and leached efficiently, increasing the copper leaching recovery rate to over 95%, while also taking into account the process's mildness, reagent economy, and environmental friendliness.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A leaching method for enhanced catalytic binding of copper ore includes the following steps:

[0008] S1: The copper ore is finely ground to 200 mesh with a particle size not greater than -0.074 mm using a wet ball milling process;

[0009] S2: Adjust the concentration of the finely ground slurry to 40%;

[0010] S3: Under stirring conditions, oxygen-enriched air is continuously introduced into the slurry via a Roots blower at a ventilation rate of 10 m / s. 3 / h;

[0011] S4: Heat the slurry to 70°C, add citric acid for enhanced catalytic pretreatment for 1.5 hours, then add 10% sulfuric acid leaching agent and leach for 3.5 hours. The total process time is 5 hours.

[0012] S5: After leaching, the slurry is separated by pressure filtration. Iron powder is added to the leachate to replace the copper and generate sponge copper. After the tailings are dried, lime is added to adjust the pH value to 7 for use in brick making.

[0013] Furthermore, in step S1, the stirring rate of the wet ball mill is 300 r / min, the ball milling time is 2.5 hours, and the qualified particle size of the mineral particles is not less than 98%.

[0014] Furthermore, in step S4, the amount of citric acid used is 3% of the mass of the copper ore.

[0015] Furthermore, in step S4, a biomass pellet steam generator is used to heat the slurry, with a temperature control accuracy of ±1℃.

[0016] Furthermore, in step S4, the amount of sulfuric acid leaching agent used is 8% of the mass of the copper ore, and the pH value of the slurry is maintained between 1.5 and 2.0 during the leaching process.

[0017] Furthermore, in step S5, the purity of the iron powder is not less than 98%, the displacement reaction time is 1 hour, and the grade of the generated sponge copper is not less than 85%.

[0018] Furthermore, in step S5, the moisture content of the tailings after dry discharge is no more than 15%, and the brick strength reaches MU10 level after brick making.

[0019] Beneficial effects of this invention:

[0020] 1. Significantly improved leaching recovery rate: This invention reduces the particle size of minerals through fine grinding, and combines the synergistic effects of organic acid catalysis, heating and oxygen enrichment to achieve complete dissolution of iron-manganese inclusions, so that the fine copper minerals are completely dissociated. The subsequent sulfuric acid leaching agent can fully contact the copper minerals, increasing the copper leaching recovery rate from 42% in the prior art to 95%, which greatly improves the utilization rate of combined copper ore resources.

[0021] 2. Mild and economical process conditions: This invention adopts a heated and atmospheric pressure process, which does not require high-pressure equipment and has low equipment investment costs; the selected organic acid (citric acid) is inexpensive, readily available, low in toxicity, environmentally friendly, and its dosage is easy to control, which reduces the process operating costs;

[0022] 3. Balancing environmental protection and resource utilization: After the tailings are dry-discharged and the pH is adjusted to neutral, they can be used for brick making, avoiding environmental pollution caused by tailings stockpiling, realizing the resource utilization of solid waste, and conforming to the development concept of green metallurgy.

[0023] 4. Simple operation and easy industrialization: The process steps of this invention are clear, and the equipment used (ball mill, Roots blower, biomass pellet steam generator, filter press, etc.) are all conventional equipment in the metallurgical industry. No special customization is required, the operation process is easy to control, and it is convenient for large-scale industrial application. Attached Figure Description

[0024] Figure 1 This is a process flow diagram of the copper ore leaching method of the present invention. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0026] The present invention proposes a method for enhancing catalytic leaching of copper ore, characterized in that:

[0027] Through in-depth research on the mineralogical characteristics of copper ore, an integrated process of fine grinding, organic acid catalysis, oxygen-enriched heating pretreatment, sulfuric acid leaching, and resource recovery was designed. The core technical solution is as follows:

[0028] (I) Key Points of Core Technologies

[0029] Fine grinding is used to reduce the particle size of the mineral, creating conditions for the leaching agent to come into contact with the copper bound inside the mineral.

[0030] By utilizing the solubility properties of organic acids (citric acid), iron and manganese inclusions are dissolved in a targeted manner, creating a pretreatment environment conducive to the dissociation of copper minerals.

[0031] Heating can be used to increase the reaction rate of organic acids with iron and manganese minerals, thereby enhancing the catalytic dissolution effect.

[0032] An oxygen-enriched aeration process was introduced, which, in conjunction with the effects of organic acids and heating, accelerated the oxidation and dissolution of iron-manganese inclusions and promoted the dissociation of copper mineral monomers.

[0033] After pretreatment, sulfuric acid leaching is used to achieve efficient dissolution of copper minerals, forming a synergistic effect mechanism of pretreatment and leaching.

[0034] (II) Complete Process Steps

[0035] S1: Fine grinding of ore: The copper ore is finely ground to 200 mesh (particle size ≤ -0.074mm) using a wet ball milling process to ensure uniform particle size and facilitate subsequent leaching agent penetration and reaction;

[0036] S2: Slurry concentration adjustment: Mix the finely ground ore with water and adjust the slurry concentration to 40% to ensure that the slurry has good fluidity and uniform reaction.

[0037] S3: Oxygen-enriched aeration treatment: Under stirring conditions, oxygen-enriched air is continuously introduced into the slurry via a Roots blower at a flow rate of 10 m / s. 3 / h, ensuring the slurry is always in a sufficiently oxygenated environment, providing the necessary conditions for the oxidation and dissolution reaction;

[0038] S4: Heating catalytic pretreatment and sulfuric acid leaching: The slurry is heated to 70°C using a biomass pellet steam generator. Citric acid is added as an enhanced catalytic medium, and the slurry is pretreated for 1.5 hours with stirring to fully dissolve the iron and manganese inclusions. Then, a 10% sulfuric acid leaching agent is added to the pretreated slurry, and the leaching is continued with stirring for 3.5 hours. The total process time is 5 hours.

[0039] S5: Subsequent processing and resource utilization: The leached slurry is separated by pressure filtration to obtain a copper sulfate-containing leachate and tailings; iron powder is added to the leachate to carry out a displacement reaction to generate sponge copper, which can be sold as a product after drying; the tailings are treated by dry discharge, and lime is added to adjust the pH value to 7. After reaching neutrality, the tailings are used for brick making, realizing the resource recovery of tailings. Specific implementation examples:

[0041] The technical solution of the present invention will be described in detail below with reference to specific embodiments, so that those skilled in the art can completely reproduce the process of the present invention.

[0042] Raw material preparation:

[0043] A copper ore deposit from a mining area in Shandong Province was selected. The copper content of the ore was 1.2%, with over 90% of the copper minerals encapsulated by iron-manganese minerals. The ore was crushed to a particle size ≤10mm for later use.

[0044] Fine grinding process:

[0045] The crushed ore is fed into a ball mill and wet ball milling is used. An appropriate amount of water is added and the ball milling time is controlled to be 2.5 hours to grind the ore to 200 mesh (-0.074 mm). After fine grinding, the slurry is screened and tested, and the particle size qualification rate is ≥98%.

[0046] Pulp conditioning:

[0047] The finely ground slurry is fed into a mixing tank, water is added to adjust the slurry concentration to 40%, the agitator is turned on, and the mixing speed is 300 r / min to keep the slurry evenly dispersed.

[0048] Oxygen-enriched aeration and heating pretreatment:

[0049] Start the Roots blower and introduce oxygen-enriched air into the slurry in the mixing tank, controlling the air flow rate to 10 m / s. 3 / h, continuous ventilation; at the same time, start the biomass pellet steam generator, heat the slurry to 70℃ through the steam heat exchanger, and maintain the temperature stable; add citric acid to the slurry, the amount of citric acid is 3% of the ore mass, keep stirring and pre-treat for 1.5 hours, and take samples for testing regularly during the period. The iron and manganese inclusion dissolution rate reaches more than 92%.

[0050] Sulfuric acid leaching:

[0051] After pretreatment, a 10% sulfuric acid solution was slowly added to the mixing tank. The amount of sulfuric acid was 8% of the ore mass. The temperature was maintained at 70℃ and the stirring rate at 300r / min. The leaching was carried out for 3.5 hours. During the leaching process, the pH value of the slurry was monitored in real time and maintained between 1.5 and 2.0.

[0052] Solid-liquid separation and product recycling:

[0053] After leaching, the slurry is sent to a plate and frame filter press for filtration to obtain leachate and tailings. Excess iron powder (iron powder purity ≥98%) is added to the leachate and stirred for 1 hour to generate sponge copper. After filtration, washing and drying, sponge copper product is obtained with a copper grade ≥85%. The tailings are dewatered by a dry discharge machine, and lime powder is added to adjust the pH value to 7. The tailings are then sent to the brick-making workshop, where they are stirred, molded and cured to produce environmentally friendly bricks with a brick strength that meets the MU10 standard.

[0054] Indicator Testing:

[0055] Chemical analysis of the sponge copper product showed a copper leaching recovery rate of 95.3%; testing of the tailings showed a copper content of ≤0.06%, meeting the emission standards.

[0056] As can be seen from the above embodiments, the process of the present invention is stable and reliable, and can achieve efficient leaching of copper ore and comprehensive utilization of resources, resulting in significant economic and environmental benefits.

[0057] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention; the actual structure is not limited thereto. In conclusion, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the spirit of the invention, such designs should fall within the protection scope of the present invention.

Claims

1. A leaching method for enhanced catalytic binding of copper ore, characterized in that, Includes the following steps: S1: The copper ore is finely ground to 200 mesh with a particle size not greater than -0.074 mm using a wet ball milling process; S2: Adjust the concentration of the finely ground slurry to 40%; S3: Under stirring conditions, oxygen-enriched air is continuously introduced into the slurry via a Roots blower at a ventilation rate of 10 m / s. 3 / h; S4: Heat the slurry to 70°C, add citric acid for enhanced catalytic pretreatment for 1.5 hours, then add 10% sulfuric acid leaching agent and leach for 3.5 hours. The total process time is 5 hours. S5: After leaching, the slurry is separated by pressure filtration. Iron powder is added to the leachate to replace the copper and generate sponge copper. After the tailings are dried, lime is added to adjust the pH value to 7 for use in brick making.

2. The leaching method for enhanced catalytic binding copper ore according to claim 1, characterized in that: In step S1, the stirring rate of the wet ball mill is 300 r / min, the ball milling time is 2.5 hours, and the qualified particle size of the mineral particles is not less than 98%.

3. The leaching method for enhanced catalytic bonding of copper ore according to claim 1, characterized in that: In step S4, the amount of citric acid used is 3% of the mass of the copper ore.

4. The leaching method for enhanced catalytic bonding of copper ore according to claim 1, characterized in that: In step S4, a biomass pellet steam generator is used to heat the slurry, with a temperature control accuracy of ±1℃.

5. The leaching method for enhanced catalytic bonding of copper ore according to claim 1, characterized in that: In step S4, the amount of sulfuric acid leaching agent used is 8% of the mass of the copper ore, and the pH value of the slurry is maintained between 1.5 and 2.0 during the leaching process.

6. The leaching method for enhanced catalytic bonding of copper ore according to claim 1, characterized in that: In step S5, the purity of the iron powder is not less than 98%, the displacement reaction time is 1 hour, and the grade of the generated sponge copper is not less than 85%.

7. The leaching method for enhanced catalytic binding copper ore according to claim 1, characterized in that: In step S5, the moisture content of the tailings after dry discharge is no more than 15%, and the brick strength reaches MU10 level after brick making.

Images