Method for comprehensive recovery of low-iron high-silicon copper-cobalt concentrate

Abstract

The application discloses a comprehensive recovery method of low-iron high-silicon copper-cobalt concentrate, which comprises the following steps: mixing the copper-cobalt concentrate with a silicon-containing flux, and performing oxidation smelting under a first oxygen-enriched air atmosphere to obtain primary crude copper and smelting slag; performing weak reduction smelting on the smelting slag under the presence of a first reducing agent and a second oxygen-enriched air atmosphere to obtain secondary crude copper and reduction slag; and performing reduction sulfidation on the reduction slag under the presence of a sulfidation agent and a second reducing agent and a third oxygen-enriched air atmosphere to obtain cobalt-rich copper matte and discard slag. Through the synergistic control of the three processes of oxidation blowing, weak reduction smelting and reduction sulfidation, the total copper recovery rate is greater than or equal to 98%, the cobalt recovery rate is greater than or equal to 82%, the cobalt content of the discard slag is less than or equal to 0.1%, the method is suitable for efficient metal recovery of low-iron high-silicon copper-cobalt concentrate, the process is energy-saving and environment-friendly, and the method has significant economic and environmental advantages.

Description

Technical Field

[0001] This invention relates to non-ferrous metal metallurgy, specifically to a comprehensive recovery method for low-iron, high-silicon copper-cobalt concentrate. Background Technology

[0002] Copper-cobalt mineral resources are globally strategic mineral resources. Some copper-cobalt deposits in Africa are characterized by high copper grades, low iron and sulfur content, and high silicon and magnesium content, exhibiting significant differences in chemical composition compared to conventional copper concentrates. Conventional copper concentrates have high sulfur content, and traditional pyrometallurgical processes typically employ a two-stage process of "smelting to produce sulfur - blowing to extract copper" to produce blister copper. In the smelting stage, the chemical heat released by the sulfide reaction can essentially achieve autothermal smelting. Copper is recovered from the smelting slag and some of the blowing slag through slag beneficiation. However, cobalt in the slag phase is difficult to recover effectively in this process.

[0003] The existing technology uses electric furnace smelting to obtain cobalt-containing crude copper, followed by blowing to obtain high-cobalt slag. However, electric furnace smelting has high energy consumption and poor adaptability to high-silicon and high-magnesium raw materials. The slag has a high melting point, high viscosity, and low smelting efficiency. Although conventional side-blowing technology has a large processing capacity, it is difficult to control the slag shape when processing raw materials with low iron content and high silicon and magnesium content, resulting in significant cobalt loss in the slag.

[0004] For low-iron, high-silicon copper-cobalt concentrates, the traditional "matte-making followed by smelting" process is unsustainable due to the difficulty in achieving equilibrium of the autothermal reaction and the dispersion of cobalt in the slag during multiple smelting processes, making economic recovery impossible. Therefore, there is an urgent need to develop a new process for the efficient recovery of copper and cobalt. Summary of the Invention

[0005] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a comprehensive recovery method for low-iron, high-silicon copper-cobalt concentrate, overcoming the shortcomings of traditional processes in processing low-iron, high-silicon ores, such as difficulties in slag formation and low copper and cobalt recovery rates.

[0006] Specifically, the first aspect of this invention relates to a comprehensive recovery method for low-iron, high-silicon copper-cobalt concentrate, comprising the following steps: S1. Copper-cobalt concentrate is mixed with a silicon-containing flux and oxidatively smelted under a first oxygen-enriched air atmosphere to obtain primary crude copper and smelting slag; wherein, the Fe / SiO2 mass ratio in the copper-cobalt concentrate is <1; the amount of silicon-containing flux added is such that the Fe / SiO2 mass ratio in the smelting slag is 0.25-0.62; the oxidative smelting is side-blown smelting, and the smelting conditions are: oxygen concentration in the first oxygen-enriched air 60%-80%, oxygen-to-material ratio 100-120 Nm³ / t, and molten pool temperature 1250-1320℃; or the oxidative smelting is flash smelting, and the smelting conditions are: controlling the moisture content of the copper-cobalt concentrate ≤0.3%, oxygen concentration in the first oxygen-enriched air 70%-85%, oxygen-to-material ratio 100-120 Nm³ / t, and molten pool temperature 1250-1320℃; S2. The smelting slag is subjected to weak reduction smelting in the presence of a first reducing agent and a second oxygen-enriched air atmosphere to obtain secondary crude copper and reduced slag; wherein the amount of the reducing agent added is 3%-5% of the mass of the smelting slag, and the conditions for weak reduction smelting are: oxygen concentration in the second oxygen-enriched air 40%-60%, molten pool temperature 1350-1400℃, and CO / (CO+CO2) volume fraction in the flue gas 20%-40%; S3. The reducing slag is subjected to reduction sulfidation in the presence of a sulfiding agent and a second reducing agent and a third oxygen-enriched air atmosphere to obtain cobalt-rich matte and waste slag; wherein the amount of sulfiding agent added is 10%-15% of the mass of the reducing slag; the amount of the second reducing agent added is 3%-5% of the mass of the reducing slag; the conditions for reduction sulfidation are: oxygen concentration in the third oxygen-enriched air is 60%-80%, molten pool temperature is 1300-1350℃, and the volume fraction of CO / (CO+CO2) in the flue gas is 40%-70%.

[0007] Reaction mechanism Oxidation smelting: Low-iron, high-silicon concentrates have a high copper content, and copper has a lower affinity for oxygen than Fe and S. Under an oxygen-rich atmosphere, Fe and S are preferentially oxidized to FeO and SO2, while some Cu2S is oxidized to Cu2O. Cu2O reacts with the remaining Cu2S to produce metallic copper, achieving one-step copper smelting and eliminating the need for traditional matte production. Oxidation smelting can be performed using side-blowing or flash blowing. The core reaction principle of both processes utilizes the interaction of Cu, and the products are not significantly different. The main difference lies in the requirements for the moisture content of the raw materials. Side-blowing smelting is more adaptable to the moisture content of the raw materials; copper concentrates with a moisture content of 8%-12% can usually be directly fed into the furnace, and materials with even lower moisture content can also be processed. Flash blowing, on the other hand, requires the moisture content of the copper-cobalt concentrate to be ≤0.3%.

[0008] Weak reduction smelting: Taking advantage of the difference in reducing properties between Cu and Co oxides, Cu2O is preferentially reduced to metallic copper under a weak reducing atmosphere, while CoO remains in the slag, thus achieving copper-cobalt separation.

[0009] Reduction sulfidation smelting: In a weak reducing atmosphere, an appropriate amount of sulfiding agent and reducing agent are added. Taking advantage of the strong affinity of cobalt for sulfur, Co in the slag is converted into CoS, forming liquid CoS-Cu2S-FeS ternary matte, thus achieving efficient recovery of cobalt.

[0010] Beneficial effects Adding silicon-containing flux adjusts the Fe / SiO2 ratio to 0.25-0.62. If the Fe / SiO2 ratio is too low, a complex silicate network forms in the slag, increasing the slag melting point and reducing fluidity. If the Fe / SiO2 ratio is too high, a large amount of iron needs to be added, increasing the slag volume and the loss of copper and cobalt. Controlling the oxygen concentration and oxygen-to-feed ratio ensures complete oxidation of Fe and S, improving copper yield and reducing energy consumption.

[0011] The weak reduction smelting stage maximizes copper recovery while keeping cobalt in the slag for subsequent sulfidation. If the reducing atmosphere is insufficient, Cu reduction in the slag will be incomplete; if the atmosphere is too strong, cobalt will be reduced and enter the crude copper, affecting the copper-cobalt separation effect.

[0012] Reduction sulfidation stage: Efficient cobalt enrichment. If the temperature is too low, the slag fluidity is poor, the sulfidation reaction kinetics are slow, and the separation of cobalt matte from the slag is incomplete; if the temperature is too high, energy consumption increases, and cobalt sulfide easily decomposes and enters the slag, reducing the cobalt yield. Insufficient reducing atmosphere or sulfiding agent results in incomplete Co sulfidation and high cobalt content in the discarded slag; excessive reducing atmosphere or sulfiding agent leads to excessive Fe entering the matte, diluting the cobalt grade.

[0013] This method employs a one-step copper smelting process, resulting in a higher slag yield compared to the blowing process in a two-step method. If reduction sulfidation is performed directly after oxidation smelting, Cu in the slag re-enters matte, diluting cobalt and making subsequent cobalt extraction more difficult. By utilizing the difference in reducibility between Cu and Co, Cu₂O is preferentially reduced to metallic copper under a weak reducing atmosphere. This allows for controlling the residual Cu in the slag to as low as approximately 5%, while CoO remains largely unreduced, achieving effective separation of copper and cobalt.

[0014] In summary, by combining one-step direct copper smelting with weak reduction and selective sulfidation, this method achieves a total copper recovery rate of ≥98% and a cobalt recovery rate of ≥82%, with a cobalt content of ≤0.1% in the waste slag. It is suitable for the efficient metal recovery of low-iron, high-silicon copper-cobalt concentrates, reducing intermediate steps and lowering energy consumption and investment costs. The slag is a stable, inert silicate, which is environmentally friendly.

[0015] According to some embodiments of the present invention, the silicon-containing flux is quartz.

[0016] According to some embodiments of the present invention, the first reducing agent and the second reducing agent are independently at least one of pulverized coal, natural gas or coke powder.

[0017] According to some embodiments of the present invention, the sulfiding agent is at least one of pyrite and sulfur.

[0018] According to some embodiments of the present invention, the Fe / SiO2 mass ratio in the copper-cobalt concentrate is <0.8, for example, 0.3-0.7.

[0019] Preferably, the copper-cobalt concentrate comprises the following components: Cu 33-40wt%, Fe 6.5-10.5wt%, Co 0.8-1.2wt%, S 14-18wt%, SiO2 14.5-19wt%, MgO 3-9wt%. More preferably, the copper-cobalt concentrate comprises the following components: Cu 35-40wt%, Fe 7-10wt%, Co 0.8-1.2wt%, S 15-18wt%, SiO2 16-19wt%, MgO 3-8.5wt%. This method is suitable for processing copper-cobalt concentrates with high MgO content, effectively improving the fluidity of smelting slag and avoiding the problems of incomplete melting and increased viscosity of slag caused by high MgO content.

[0020] Preferably, the moisture content of the copper-cobalt concentrate is ≤12% to avoid generating excessive waste acid during flue gas purification and reduce wastewater treatment costs.

[0021] According to some embodiments of the present invention, in the primary crude copper, the Cu content is ≥98.8wt%, the S content is ≤0.2wt%, and the Co content is ≤0.15wt%.

[0022] Preferably, in the primary crude copper, the Cu content is 98.8-99.2 wt%; and / or, the S content is ≤0.18%, for example 0.1-0.18 wt%; and / or, the Co content is ≤0.14 wt%, for example 0.1-0.14 wt%.

[0023] According to some embodiments of the present invention, the Fe / SiO2 mass ratio in the smelting slag is 0.3-0.62.

[0024] According to some embodiments of the present invention, the Cu content in the smelting slag is 15-22 wt%, and the Co content is 1.2-1.5 wt%.

[0025] Preferably, the Cu content in the smelting slag is 17-22 wt%, for example 19-22 wt%; and / or the Co content is 1.3-1.5 wt%.

[0026] According to some embodiments of the present invention, the secondary crude copper contains Cu content ≥ 98.5 wt%, Co content ≤ 0.3 wt%, and S content ≤ 0.2 wt%.

[0027] Preferably, in the secondary crude copper, the Cu content is 98.5-99 wt%; and / or, the Co content is 0.15-0.3 wt%; and / or, the S content is ≤0.15 wt%, for example, 0.1-0.12 wt%.

[0028] According to some embodiments of the present invention, the reducing slag contains 4-6 wt% Cu and 1.5-2.0 wt% Co.

[0029] Preferably, the Cu content in the reducing slag is 5-6 wt%; and / or the Co content is 1.5-1.9 wt%.

[0030] According to some embodiments of the present invention, the cobalt-rich matte contains 20-26 wt% Cu, 7-9 wt% Co, and 24-26.5 wt% S.

[0031] Preferably, the Cu content in the cobalt-rich matte is 22-25 wt%, more preferably 23-25 ​​wt%.

[0032] Preferably, the Co content in the cobalt-rich matte is 7.5-8.5 wt%, more preferably 7.5-8 wt%.

[0033] Preferably, the S content in the cobalt-rich copper matte is 24.5-26.3 wt%.

[0034] According to some embodiments of the present invention, the waste residue contains Cu content ≤ 0.2 wt% and Co content ≤ 0.1 wt%.

[0035] Preferably, the Cu content in the waste residue is ≤0.18wt%, for example, 0.15-0.18wt%.

[0036] Preferably, the Co content in the waste residue is ≤0.08wt%, for example, 0.06-0.07wt%.

[0037] According to some embodiments of the present invention, the process further includes injecting fuel oil into the molten pool during the oxidation smelting step to supplement the heat required for smelting. For example, within the aforementioned ore composition range, the amount of fuel oil added is 2%-2.5% of the ore raw material mass.

[0038] According to some embodiments of the present invention, the oxidative smelting is a side-blown smelting, wherein the oxygen concentration in the first oxygen-enriched air is 65%-75% and the oxygen-to-material ratio is 105-115 Nm³ / t.

[0039] According to some embodiments of the present invention, the oxidative smelting time is 2-4 hours, for example 2-3 hours, or 2-2.5 hours.

[0040] According to some embodiments of the present invention, in the weak reducing smelting, the amount of reducing agent added is 3.5%-4.5% of the mass of the smelting slag.

[0041] According to some embodiments of the present invention, the weak reduction smelting time is 1.5-2.5h, for example 2-2.5h.

[0042] According to some embodiments of the present invention, during the reduction sulfidation process, the amount of sulfiding agent added is 12%-15% of the mass of the reduction slag, preferably 12.5%-14.5%.

[0043] According to some embodiments of the present invention, during the reduction sulfidation process, the amount of the second reducing agent added is 3.5%-4.5% of the mass of the reduction slag, preferably 4%-4.5%.

[0044] According to some embodiments of the present invention, the temperature of the molten pool during the reduction vulcanization process is 1300-1350°C.

[0045] According to some embodiments of the present invention, during the reduction vulcanization process, the volume fraction of CO / (CO+CO2) in the flue gas is 45%-65%, preferably 50%-60%.

[0046] The combustion of fixed carbon in coal mainly involves the following reactions: 2C + O2 = 2CO; C + O₂ = CO₂.

[0047] By adjusting the air volume and pulverized coal feed rate (i.e., the air-to-coal ratio), the molar ratio of oxygen to carbon can be controlled to obtain a mixture of CO and CO2 and regulate the partial pressure of CO (CO / (CO+CO2)). This ratio, along with the furnace temperature, affects the selective reduction of metals.

[0048] According to some embodiments of the present invention, the reduction vulcanization time is 1-2 hours.

[0049] According to some embodiments of the present invention, the weak reduction smelting and / or the reduction vulcanization are side-blown smelting.

[0050] In this article, "approximately" or "around" indicates that the allowable error is within ±5%. For example, approximately 100 means 100 ± 5% × 100.

[0051] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. Attached Figure Description

[0052] Figure 1 This is a process flow diagram of Embodiment 1 of the present invention. Detailed Implementation

[0053] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0054] Unless otherwise specified, all raw materials or equipment involved are commercially available standard products.

[0055] Example 1 This embodiment processes a typical complex copper-cobalt concentrate. Its main chemical composition by dry weight is shown in Table 1, and its moisture content is 8%.

[0056] Table 1: Main components (wt%) of the concentrate fed into the furnace in Example 1

[0057] Step 1: Oxidation blowing The concentrate, mixed with 2.5% quartz sand to adjust the slag shape, is added to the first side-blown furnace through the feed port. Oxygen-enriched air (70% oxygen concentration) is introduced through the side-blown nozzles, controlling the fuel oil ratio at 2.2% and the oxygen-to-material ratio at 110 Nm. 3 / t, the molten pool temperature is controlled at 1280℃. After smelting for 2 hours, blowing is stopped and slag-copper separation is carried out. The composition of the produced primary crude copper and smelting slag is shown in Table 2.

[0058] Table 2: Main components (wt%) of the first step product of Example 1

[0059] The direct copper recovery rate is approximately 78%, the cobalt slag incorporation rate is >96%, and the cobalt is enriched in the slag to 1.32%.

[0060] Step 2: Weak reduction smelting The molten slag produced in the first step is directly fed into the second side-blown furnace via a high-temperature chute. The temperature of the second side-blown furnace is controlled at 1380℃. Oxygen-enriched air (40% oxygen concentration) and pulverized coal are injected through a spray gun. The amount of pulverized coal added is 4% of the slag weight. The air-to-coal ratio is adjusted to 2650 Nm³. 3 / t, control the CO / (CO+CO2) volume ratio in the flue gas inside the furnace to be around 30%. After reacting for 2 hours, allow it to stand and separate into layers. The composition of the secondary crude copper and reducing slag produced is shown in Table 3.

[0061] Table 3: Main components (wt%) of the product from step 2 of Example 1

[0062] The cumulative direct recovery rate of copper increased to approximately 95.5%, and the grade of cobalt in slag further improved to 1.68%.

[0063] Step 3: Reduction Sulfidation The liquid reduction slag produced in the second step is placed into a third side-blown furnace, along with pyrite (approximately 12.9% of the slag weight) and pulverized coal (approximately 4.1% of the slag weight). The temperature is controlled at 1320℃, the oxygen concentration at 60%, and the air-to-coal ratio is adjusted to 1700 Nm³. 3 The volume ratio of CO / (CO+CO2) in the flue gas inside the furnace was maintained at approximately 55% for sulfidation smelting for 1.5 hours. The smelting products were clarified and separated to obtain cobalt matte and waste slag, the composition of which is shown in Table 4.

[0064] Table 4: Main components (wt%) of the product from step 3 of Example 1

[0065] Calculations show that the total copper recovery rate of this process (including copper in the crude copper obtained from the two steps and copper in cobalt matte) is 98.5%, and the cobalt recovery rate (based on cobalt matte) is 85.8%.

[0066] Example 2 This embodiment is used to verify the adaptability of the process under conditions of high iron content and low silicon content in the raw materials. A copper-cobalt concentrate was processed; its main chemical composition by dry weight is shown in Table 5, and its moisture content is 10%.

[0067] Table 5: Main components (wt%) of the concentrate fed into the furnace in Example 2

[0068] Step 1: Oxidation blowing Due to the increased iron content and relatively insufficient SiO2 content in the raw materials, more quartz flux (5.5%) needs to be added. The mixture is then added to the first side-blown furnace. The oxygen enrichment concentration is adjusted to 68%, the fuel oil ratio is adjusted to 2.0%, the oxygen-to-material ratio is controlled at 105 Nm³ / t, and the molten pool temperature is controlled at 1260℃. After blowing for 2.2 hours, blowing is stopped, and slag-copper separation is performed. The product composition is shown in Table 6.

[0069] Table 6: Main components (wt%) of the first step product of Example 2

[0070] The cobalt enrichment ratio in smelting slag (the ratio of cobalt content in the slag to cobalt content in the ore raw material) is approximately 1.41.

[0071] Step 2: Weak reduction smelting The liquid slag obtained in the first step was placed into a second side-blown furnace, and the temperature was controlled at 1360℃. Oxygen-enriched air was mixed with pulverized coal and injected, with an oxygen concentration of 50%. The amount of pulverized coal added was adjusted to 3.8% of the slag amount, and the volume ratio of CO / (CO+CO2) in the flue gas was controlled at around 20%. The reaction was allowed to proceed for 2 hours, followed by settling. The product composition is shown in Table 7.

[0072] Table 7: Main components (wt%) of the product from step 2 of Example 2

[0073] Step 3: Reduction Sulfidation The liquid reduction slag produced in the second step was placed into a third side-blown furnace, and pyrite (approximately 14.3% of the slag weight) and pulverized coal (approximately 4.0% of the slag weight) were added. The temperature was controlled at 1300℃, the oxygen concentration at 70%, and the CO / (CO+CO2) volume ratio was controlled at approximately 60%. The reaction was carried out for 1.5 hours. The product composition is shown in Table 8.

[0074] Table 8: Main components (wt%) of the product from step 3 of Example 2

[0075] In this embodiment, the total copper recovery rate was 98.2%, the cobalt recovery rate was 82.8%, and the waste residue met the standards.

[0076] Example 3 This embodiment is used to verify the adaptability of the process under conditions of increased magnesium oxide and complex gangue content in the raw materials. A copper-cobalt concentrate with a high magnesium content was processed; its main chemical composition by dry weight is shown in Table 9, and its moisture content is 12%.

[0077] Table 9: Main components (wt%) of the concentrate fed into the furnace in Example 3

[0078] Step 1: Oxidation blowing The mixture was added to the first side-blown furnace, along with 2% silica sand. To ensure slag fluidity, the molten pool temperature was increased to 1320℃, the oxygen concentration was 72%, the fuel oil ratio was 2.5%, and the oxygen-to-material ratio was 115 Nm³ / t. After 2.5 hours of blowing, blowing was stopped, and slag-copper separation was performed. The product composition is shown in Table 10.

[0079] Table 10: Main components (wt%) of the first step product of Example 3

[0080] The cobalt enrichment ratio in smelting slag (the ratio of cobalt content in the slag to cobalt content in the ore raw material) is approximately 1.49.

[0081] Step 2: Weak reduction smelting The molten slag obtained in the first step was placed into the second side-blown furnace. Since the MgO content in the slag was close to 10%, the molten pool temperature was increased to 1400℃ to ensure the reduction kinetics conditions. The oxygen concentration was 60%, and the amount of pulverized coal added was 4.5% of the slag weight (to compensate for heat loss at high temperatures). The CO / (CO+CO2) volume ratio in the flue gas was controlled at approximately 40%. The reaction was allowed to proceed for 2.2 hours, followed by settling and stratification. The product composition is shown in Table 11.

[0082] Table 11: Main components (wt%) of the product from step 2 of Example 3

[0083] The cobalt slag grade is 1.88%, and the enrichment effect is good.

[0084] Step 3: Reduction Sulfidation The liquid reduction slag produced in the second step was placed into a third side-blown furnace, with approximately 13.2% pyrite and approximately 4.5% pulverized coal added. The molten pool temperature was controlled at 1340℃, the oxygen concentration at 75%, and the CO / (CO+CO2) volume ratio at approximately 50%. The reaction was carried out for 1.5 hours. The product composition is shown in Table 12.

[0085] Table 12: Main components (wt%) of the product from step 3 of Example 3

[0086] In this embodiment, the total copper recovery rate was 98.3%, the cobalt recovery rate was 84.5%, and the waste residue met the standards. This indicates that the process of the present invention can effectively process copper-cobalt concentrate under high-magnesium and complex gangue conditions, and has a wide range of applications.

[0087] Comparative Example 1 The difference compared to Example 1 is that a large amount of iron was added in the first step until the Fe / SiO2 ratio of the smelting slag was 1.9.

[0088] The results showed that increasing the slag volume by 1.6 times resulted in a final total copper recovery rate of 94.2% and a cobalt recovery rate of 72.5%. Under the same smelting conditions, the cobalt content in the slag did not differ significantly. However, increasing the slag volume led to an increase in the total amount of cobalt carried away by the slag, thus significantly reducing the cobalt recovery rate.

[0089] Comparative Example 2 Compared with Example 1, the difference is that in the second step, the volume ratio of CO / (CO+CO2) in the flue gas in the furnace is controlled at about 60%, resulting in the secondary crude copper containing 0.5wt% cobalt and the cobalt recovery rate decreasing to 70.3%.

[0090] Comparative Example 3 Compared with Example 1, the difference is that in the third step, the amount of pyrite added is about 25% of the slag amount.

[0091] In the final cobalt matte, the FeS content increased while the Co content decreased to 5 wt%. Increasing the amount of sulfiding agent did not significantly affect the recovery rate, but the increased iron content in the cobalt matte diluted the cobalt, leading to a decrease in the pricing factor and increased energy consumption and slag volume in subsequent processing. Furthermore, increasing the amount of sulfiding agent also increased the overall processing cost.

[0092] Comparative Example 4 Compared to Example 1, the difference lies in that the molten pool temperature is controlled at 1400℃ in the third step. Excessive temperature leads to CoS decomposition, causing some cobalt to re-enter the slag phase. The Co content in the discarded slag exceeds 0.15%, and the cobalt recovery rate drops to 73.9%.

[0093] In summary, the process of this invention achieves efficient copper-cobalt separation and recovery from complex copper-cobalt concentrates with low iron, high silicon, and high magnesium through three steps: oxidation blowing, weak reduction smelting, and reduction sulfidation. The total copper recovery rate reaches 98.2%-98.5%, the comprehensive cobalt recovery rate is 82.8%-85.8%, and the cobalt content in the waste slag is as low as 0.06%-0.07%. The process has wide adaptability and controllable operation, significantly reducing copper and cobalt losses. At the same time, it reduces intermediate links, saves energy, and is environmentally friendly, thus having significant economic and environmental advantages.

Claims

1. A comprehensive recovery method for low-iron, high-silicon copper-cobalt concentrate, characterized in that: Includes the following steps: S1. Copper-cobalt concentrate is mixed with a silicon-containing flux and oxidatively smelted under a first oxygen-enriched air atmosphere to obtain primary crude copper and smelting slag; wherein, the Fe / SiO2 mass ratio in the copper-cobalt concentrate is <1; the amount of silicon-containing flux added is such that the Fe / SiO2 mass ratio in the smelting slag is 0.25-0.62; the oxidative smelting is side-blown smelting, and the smelting conditions are: oxygen concentration in the first oxygen-enriched air 60%-80%, oxygen-to-material ratio 100-120 Nm³ / t, and molten pool temperature 1250-1320℃; or the oxidative smelting is flash smelting, and the smelting conditions are: controlling the moisture content of the copper-cobalt concentrate ≤0.3%, oxygen concentration in the first oxygen-enriched air 70%-85%, oxygen-to-material ratio 100-120 Nm³ / t, and molten pool temperature 1250-1320℃; S2. The smelting slag is subjected to weak reduction smelting in the presence of a first reducing agent and a second oxygen-enriched air atmosphere to obtain secondary crude copper and reduced slag; wherein the amount of the reducing agent added is 3%-5% of the mass of the smelting slag, and the conditions for weak reduction smelting are: oxygen concentration in the second oxygen-enriched air 40%-60%, molten pool temperature 1350-1400℃, and CO / (CO+CO2) volume fraction in the flue gas 20%-40%; S3. The reducing slag is subjected to reduction sulfidation in the presence of a sulfiding agent and a second reducing agent and a third oxygen-enriched air atmosphere to obtain cobalt-rich matte and waste slag; wherein the amount of sulfiding agent added is 10%-15% of the mass of the reducing slag; the amount of the second reducing agent added is 3%-5% of the mass of the reducing slag; the conditions for reduction sulfidation are: oxygen concentration in the third oxygen-enriched air is 60%-80%, molten pool temperature is 1300-1350℃, and the volume fraction of CO / (CO+CO2) in the flue gas is 40%-70%.

2. The comprehensive recovery method for low-iron, high-silicon copper-cobalt concentrate according to claim 1, characterized in that: The silicon-containing flux is quartz; And / or, the first reducing agent and the second reducing agent are independently at least one of pulverized coal, natural gas or coke powder; And / or, the sulfiding agent is at least one of pyrite and sulfur.

3. The comprehensive recovery method for low-iron, high-silicon copper-cobalt concentrate according to claim 1, characterized in that: The Fe / SiO2 mass ratio in the copper-cobalt concentrate is <0.

8.

4. The comprehensive recovery method for low-iron, high-silicon copper-cobalt concentrate according to claim 1, characterized in that: The copper-cobalt concentrate comprises, by mass percentage: Cu 33-40wt%, Fe 6.5-10.5wt%, Co 0.8-1.2wt%, S 14-18wt%, SiO2 14.5-19wt%; and / or, the moisture content of the copper-cobalt concentrate is ≤12%.

5. The comprehensive recovery method for low-iron, high-silicon copper-cobalt concentrate according to claim 1, characterized in that: In the primary crude copper, the Cu content is ≥98.8wt%, the S content is ≤0.2wt%, and the Co content is ≤0.15wt%. And / or, in the smelting slag, the Fe / SiO2 mass ratio is 0.3-0.62; And / or, in the smelting slag, the Cu content is 15-22 wt% and the Co content is 1.2-1.5 wt%.

6. The comprehensive recovery method for low-iron, high-silicon copper-cobalt concentrate according to claim 1, characterized in that: The secondary crude copper has a Cu content ≥ 98.5 wt%, a Co content ≤ 0.3 wt%, and a S content ≤ 0.2 wt%. And / or, in the reducing residue, the Cu content is 4-6 wt% and the Co content is 1.5-2.0 wt%.

7. The comprehensive recovery method for low-iron, high-silicon copper-cobalt concentrate according to claim 1, characterized in that: The cobalt-rich matte contains 20-26 wt% Cu, 7-9 wt% Co, and 24-26.5 wt% S. And / or, in the waste residue, the Cu content is ≤0.2wt% and the Co content is ≤0.1wt%.

8. The comprehensive recovery method for low-iron, high-silicon copper-cobalt concentrate according to claim 1, characterized in that: It also includes injecting fuel oil into the molten pool during the oxidation smelting step to supplement the heat required for smelting.

9. The comprehensive recovery method for low-iron, high-silicon copper-cobalt concentrate according to claim 1, characterized in that: The oxidation smelting time is 2-4 hours; And / or, the weak reduction smelting time is 1.5-2.5h; And / or, during the reduction vulcanization process, the molten pool temperature is 1300-1340℃; And / or, the reduction vulcanization time is 1-2 hours.

10. The comprehensive recovery method for low-iron, high-silicon copper-cobalt concentrate according to claim 1, characterized in that: The weak reduction smelting and / or the reduction vulcanization are performed by side-blown smelting.

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