A method for collaborative regulation of high oxygen-enriched copper smelting slag gold separation and slag resourceization

Abstract

The present application belongs to copper pyrometallurgy technical field, and particularly relates to a method for collaborative regulation of high oxygen-enriched copper smelting slag gold separation and slag resource utilization. The method is implemented in an oxygen-enriched side-blown or double-side-blown smelting furnace. During the main smelting by blowing high-concentration oxygen-enriched air through a primary tuyere, a mixture of powdered reducing medium and a specific proportion of slag modifier is collaboratively injected through a spatially-separated auxiliary tuyere at a specific angle. The mass ratio of alumina to calcium oxide in the modifier is (0.3-0.5):1. The smelting temperature and final slag composition are controlled, and a dynamic feedback control mechanism based on the smelted slag magnetite content or viscosity is established to automatically adjust the injection amount. The present application can in-situ inhibit the over-oxidation of smelted slag at the smelting source, significantly reduce the viscosity and magnetite content of the smelted slag, thereby stably reducing the copper content of the discarded slag to a low level, greatly improving the slag-gold separation effect, and simultaneously reducing the energy consumption and cost of subsequent resource utilization treatment of the smelted slag.

Description

Technical Field

[0001] This invention belongs to the field of copper pyrometallurgical technology, specifically relating to a synergistic control method for slag-gold separation and slag resource utilization in copper smelting processes with high oxygen enrichment and double-sided blowing pools. Background Technology

[0002] In the field of non-ferrous metal pyrometallurgy, oxygen-enriched side-blown or double-side-blown molten pool copper smelting technology is widely used due to its advantages such as high smelting intensity and low energy consumption. However, as the oxygen concentration increases to 70% or even higher, a highly oxidizing atmosphere is formed in the molten pool, causing a large amount of ferrous sulfide in the furnace charge to be oxidized into high-melting-point magnetite. Its enrichment in the slag drastically increases slag viscosity, deteriorates fluidity, and severely hinders the settling and separation of matte particles, resulting in increased copper content in the waste slag and decreased direct metal recovery. How to inhibit slag over-oxidation and improve its properties from the process source has become a key bottleneck restricting the full realization of the potential of high-oxygen-enriched smelting technology.

[0003] Currently, existing technologies for the treatment and control of copper smelting slag mainly follow the approach of "end-of-pipe treatment" or "static prevention," which has significant limitations. Firstly, these methods involve separate depletion or resource recovery of the produced slag, which are remedial measures implemented after the fact. For example, CN107641717A discloses a method for heating copper-containing slag in a separate reaction unit and adding additives for conditioning and separation; CN111298982B and CN115386723A respectively involve recovering valuable metals from smelting slag through flotation reagents or vacuum roasting. While these methods can recover some value, they increase the need for separate processing units, complex processes, and additional energy consumption and costs, without solving the fundamental problem of difficult slag-metal separation during the initial smelting process. Secondly, some methods involve statically optimizing the furnace charge ratio before smelting, such as CN102994775A, which involves pre-mixing reducing agents and fluxes before charging the furnace. These methods are open-loop controls, unable to adjust in real time according to the dynamically changing reaction conditions within the molten pool. Their effectiveness in suppressing the peroxidation state of the slag under high oxygen-enriched conditions is limited and unstable. Furthermore, patented technologies such as WO2019071795A1, CN116162846B, and CN119951860A focus on the resource utilization or recovery of valuable components after slag production, similarly failing to address the real-time process challenges caused by the high viscosity of the slag during smelting. In summary, existing technologies lack an effective means for in-situ, active, and dynamic control of the oxidation state and physicochemical properties of slag during high oxygen-enriched smelting.

[0004] Therefore, there is an urgent need to develop an innovative method that can be integrated into the smelting process to synergistically optimize slag-gold separation efficiency from the source and create favorable conditions for downstream resource utilization. Summary of the Invention

[0005] To address the aforementioned problems in existing technologies, this invention provides a method for the synergistic regulation of gold separation and slag resource utilization in high-oxygen-enriched copper smelting slag, comprising the following steps:

[0006] a) Smelting step: Oxygen-enriched air with an oxygen concentration greater than 70% is blown into the molten pool through the primary tuyeres of the smelting furnace to oxidize and smelt the copper-containing material.

[0007] b) In-situ coordinated control step: A mixture is co-injected into the molten pool through an auxiliary tuyer spatially separated from the primary tuyer. The mixture contains a powdered reducing medium and a slag conditioner. The injection direction of the auxiliary tuyer forms an angle of 10° to 30° with the oxygen-enriched airflow of the primary tuyer. The slag conditioner is a mixed powder containing calcium oxide and alumina, and the mass ratio of alumina to calcium oxide is (0.3 to 0.5):1.

[0008] c) Dynamic feedback control step: Dynamic feedback control is performed based on real-time monitoring of the slag state, including: monitoring the iron oxide content in the slag and / or the viscosity estimated based on the slag composition and temperature; when the monitored iron oxide content or estimated viscosity reaches a preset control threshold, the injection amount of the mixture in step b) is automatically increased.

[0009] Furthermore, in step a), the oxygen concentration of the oxygen-enriched air is 70% to 85%.

[0010] Further, in step b), the reducing medium is selected from one or more of coke powder, coal powder, and graphite powder.

[0011] Furthermore, the final slag composition is adjusted through steps b) and c) to meet the following conditions: the iron-silicon mass ratio is 1.8 to 2.2, the calcium oxide content is 3.0 wt.% to 5.0 wt.%, and the alumina content is 3.5 wt.% to 5.5 wt.%.

[0012] Furthermore, the content of ferric oxide in the final slag should not exceed 4.5 wt.%.

[0013] Further, in step c), the preset control threshold is: the content of iron tetroxide is greater than 4.0 wt.%.

[0014] Furthermore, the melting temperature in step a) is controlled at 1350–1380°C.

[0015] Further, in step b), the initial injection amount of the mixture accounts for 1.0% to 2.5% of the total mass of the dry material entering the furnace.

[0016] This invention achieves the following beneficial technical effects through the organic combination of spatial separation coordinated injection, specific slag quality regulators, and dynamic feedback control:

[0017] First, it significantly improves the slag-gold separation efficiency under high oxygen-enriched conditions. By constructing localized reduction micro-zones at the smelting source and adjusting the slag structure in situ, the excessive formation of Fe3O4 is effectively suppressed, significantly reducing slag viscosity and improving fluidity, thereby greatly promoting the aggregation and sedimentation of matte particles. This allows the copper content in the final slag to be stably controlled at a low level (e.g., below 1.2%), reducing the copper content in the slag by more than 50% compared to traditional high oxygen-enriched operations, directly improving the copper recovery rate.

[0018] Secondly, it enhances the adaptability and stability of the entire smelting process. The established dynamic feedback control mechanism based on key slag indicators (such as Fe3O4 content) can respond in real time to changes in operating conditions such as fluctuations in raw material composition, and automatically adjust the injection volume of reducing medium and regulator. This intelligent closed-loop control gives the process strong anti-disturbance capabilities, ensuring continuous and smooth production under high oxygen concentrations (such as >80%), allowing the potential for intensified smelting to be safely and fully released.

[0019] Third, it achieves cross-process synergistic optimization, bringing benefits to the overall greenness and economy of the process. The slag produced by this method has the characteristics of low Fe3O4 content and excellent phase structure, becoming a "reduction-friendly" intermediate product. This creates extremely favorable initial conditions for subsequent slag resource utilization (such as reduction to prepare copper-iron alloys or building materials), which can significantly reduce the consumption of reducing agents in downstream processes (by about 15%), while improving the quality of resource-based products, forming a synergistic effect from smelting to resource recovery. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the process for the synergistic regulation of gold separation and slag resource utilization in high-oxygen copper smelting slag according to the present invention. Detailed Implementation

[0021] The following detailed description, in conjunction with specific embodiments, provides a clear and complete explanation of the synergistic regulation method for gold separation and slag resource utilization in high-oxygen-enriched copper smelting slag according to the present invention. Those skilled in the art will understand that the following description is intended as illustrative and not as a limitation on the scope of protection of the present invention.

[0022] This invention relates to a copper smelting furnace employing oxygen-enriched side-blowing or dual-side-blowing technology, designed to process copper-containing materials such as copper concentrate. Its core lies in the simultaneous on-site, dynamic, and coordinated control of the slag state through an integrated and intelligent system during primary oxidation smelting, achieving efficient slag-gold separation and producing slag easily processed subsequently.

[0023] In practice, oxidation smelting is carried out first. High-concentration oxygen-enriched air is blown into the molten pool through primary tuyeres located on the side wall of the smelting furnace. The oxygen concentration of this oxygen-enriched air is preferably controlled between 70% and 85% to provide a strong oxidizing atmosphere and stirring kinetic energy, ensuring efficient oxidation of sulfides and rapid smelting reactions. The temperature in the smelting reaction zone needs to be precisely maintained within the range of 1350℃ to 1380℃, requiring coordinated adjustment of fuel and air parameters.

[0024] The key innovation of this invention lies in the in-situ coordinated control step performed simultaneously with the main smelting process. This step is achieved through an auxiliary injection system independent of the primary tuyeres. The auxiliary tuyeres are typically located near the primary tuyeres but spatially separated, with their injection direction at an angle controlled between 10° and 30° to the primary oxygen-enriched airflow. Through these auxiliary tuyeres, a specially formulated mixture is injected into the molten pool, particularly into the slag layer region. This mixture consists of a powdered reducing medium (such as coke powder, coal powder, or graphite powder) and a slag conditioner in a specific ratio. The slag conditioner is a mixed powder of calcium oxide (CaO) and alumina (Al2O3), characterized by a strictly limited mass ratio of Al2O3 to CaO between 0.3:1 and 0.5:1. This spatially separated and angled injection method aims to create a dynamic, localized reducing micro-zone at the oxygen-enriched airflow interface above the molten pool. The reducing medium consumes excess oxygen, inhibiting the excessive formation of high-melting-point Fe3O4 from the source. Meanwhile, a specific ratio of CaO-Al2O3 acts as a highly efficient network structure modifier, effectively disrupting the complex silicate structure in the slag, significantly reducing its melting point and viscosity, thereby synergistically improving slag fluidity and creating favorable conditions for the settling of matte particles. Through the initial proportioning of raw materials and the adjustment of this synergistic injection, the final composition of the waste slag is controlled to meet the following requirements: an iron-silicon ratio (Fe / SiO2) of 1.8–2.2, a CaO content of 3.0%–5.0%, an Al2O3 content of 3.5%–5.5%, and a target Fe3O4 content in the final slag set at no more than 4.5%.

[0025] To achieve precision and stability in the process, this invention also establishes a dynamic feedback closed-loop control mechanism based on the slag state. This mechanism continuously acquires key parameters reflecting the oxidation state and fluidity of the slag through online monitoring systems (such as flue gas oxygen content analysis) or periodic offline sampling analysis (such as chemical titration to determine Fe3O4). The core monitoring indicators are the Fe3O4 content in the slag and / or the estimated viscosity calculated based on real-time composition and temperature. The control system presets a safety threshold (e.g., Fe3O4 content greater than 4.0%). When monitoring data indicates that the slag has over-oxidized or its viscosity is increasing and reaches this threshold, the control system immediately and automatically issues a command to increase the injection rate of the reducing medium and slag conditioner mixture at the auxiliary tuyeres. This immediate and proactive intervention can quickly restore the slag properties to the ideal range, enabling the entire system to adaptively adjust to complex conditions such as fluctuations in raw material input and changes in oxygen potential, ensuring the stable and efficient operation of the high-oxygen-enriched intensified smelting process.

[0026] Example 1: Standard Operating Condition Application

[0027] In an 80m 3 In a double-sided blown furnace, copper concentrate with a copper grade of 25% is processed. Smelting is carried out by blowing oxygen-enriched air (80% oxygen concentration) through the primary tuyeres. Simultaneously, a mixture (coke powder and a modifier with an Al₂O₃:CaO ratio of 0.4:1) is injected at a 20° angle through the auxiliary tuyeres, with an initial injection rate of 1.5% of the total dry material. The molten pool temperature is controlled at 1360℃, and the final slag iron-silicon ratio is 2.0. Through dynamic monitoring and feedback, the process operates smoothly, with the Fe₃O₄ content in the produced waste slag remaining stable at 3.2%, the copper content in the slag decreasing to 0.95%, and the matte grade reaching 72%.

[0028] Example 2: Dynamic Feedback Response Demonstration

[0029] Based on the stable operation of Example 1, a fluctuation in the low sulfur content of the simulated raw material was observed, leading to a sudden increase in the oxygen concentration in the flue gas. The monitoring system predicted that the Fe3O4 content in the slag would exceed the limit, and then automatically increased the amount of the co-injected mixture from 1.5% to 2.2%. After about 30 minutes, the process parameters returned to normal, and the peak Fe3O4 content in the slag was only 3.8%, effectively preventing the deterioration of slag-metal separation.

[0030] Example 3: Limiting Parameter Verification

[0031] By increasing the oxygen concentration to the upper limit of 85%, using the upper limit of the regulator ratio of m(Al2O3):m(CaO) = 0.5:1, and maintaining a 10° injection angle, the method of this invention was implemented under these stringent conditions. Ultimately, the Fe3O4 content in the waste slag was controlled at 4.3%, and the copper content in the slag was 1.15%, demonstrating the wide applicability and robustness of the method.

[0032] Comparative example: Traditional high-oxygen operation

[0033] Under the same conditions as in Example 1, only the co-purge system was shut down. As a result, the slag became viscous, difficult to discharge, and the final discarded slag had an Fe3O4 content as high as 8.1% and a copper content that surged to 2.4%, significantly inferior to the results of the present invention.

[0034] In summary, this invention successfully solves the industry problem of slag over-oxidation in high-oxygen smelting by organically combining in-situ coordinated blowing at the smelting source with dynamic intelligent control. While improving the metal recovery rate, it also provides high-quality raw materials for downstream slag resource utilization, and has significant industrial application value.

[0035] The above description is a preferred embodiment of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for synergistic regulation of gold separation and slag resource utilization in high-oxygen-enriched copper smelting slag, characterized in that, Includes the following steps: a) Smelting step: Oxygen-enriched air with an oxygen concentration greater than 70% is blown into the molten pool through the primary tuyeres of the smelting furnace to oxidize and smelt the copper-containing material. b) In-situ coordinated control step: A mixture is co-injected into the molten pool through an auxiliary tuyer spatially separated from the primary tuyer. The mixture contains a powdered reducing medium and a slag conditioner. The injection direction of the auxiliary tuyer forms an angle of 10° to 30° with the oxygen-enriched airflow of the primary tuyer. The slag conditioner is a mixed powder containing calcium oxide and alumina, and the mass ratio of alumina to calcium oxide is (0.3 to 0.5):

1. c) Dynamic feedback control step: Dynamic feedback control is performed based on real-time monitoring of the slag state, including: monitoring the iron oxide content in the slag and / or the viscosity estimated based on the slag composition and temperature; when the monitored iron oxide content or estimated viscosity reaches a preset control threshold, the injection amount of the mixture in step b) is automatically increased.

2. The method for synergistic regulation of high-oxygen-enriched copper smelting slag gold separation and slag resource utilization according to claim 1, characterized in that, In step a), the oxygen concentration of the oxygen-enriched air is 70% to 85%.

3. The method for synergistic regulation of high-oxygen-enriched copper smelting slag gold separation and slag resource utilization according to claim 1, characterized in that, In step b), the reducing medium is selected from one or more of coke powder, coal powder, and graphite powder.

4. The method for synergistic regulation of high-oxygen-enriched copper smelting slag gold separation and slag resource utilization according to claim 1, characterized in that, By adjusting the composition of the final slag through steps b) and c), the following conditions are met: the iron-silicon mass ratio is 1.8 to 2.2, the calcium oxide content is 3.0 wt.% to 5.0 wt.%, and the alumina content is 3.5 wt.% to 5.5 wt.%.

5. The method for synergistic regulation of high-oxygen-enriched copper smelting slag gold separation and slag resource utilization according to claim 1 or 4, characterized in that, The content of ferric oxide in the final residue should not exceed 4.5 wt.%.

6. The method for synergistic regulation of high-oxygen-enriched copper smelting slag gold separation and slag resource utilization according to claim 1, characterized in that, In step c), the preset control threshold is: the content of iron tetroxide is greater than 4.0 wt.%.

7. The method for synergistic regulation of high-oxygen-enriched copper smelting slag gold separation and slag resource utilization according to claim 1, characterized in that, The melting temperature in step a) is controlled at 1350–1380°C.

8. The method for synergistic regulation of high-oxygen-enriched copper smelting slag gold separation and slag resource utilization according to claim 1, characterized in that, In step b), the initial injection amount of the mixture accounts for 1.0% to 2.5% of the total mass of the dry material entering the furnace.

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