Method for capturing and recycling metal molybdenum in copper smelting slag through liquid alloy phase
By using a liquid alloy phase trapping method, the reaction of metallic copper alloy with carbon powder and calcium oxide in molten copper slag was utilized, which solved the problem of low molybdenum recovery rate in copper slag, achieved efficient molybdenum recovery and online separation, and simplified the process flow.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-08
- Publication Date
- 2026-04-03
AI Technical Summary
Existing technologies for recovering molybdenum from copper slag have low recovery rates, complex processes, and suffer from low molybdenum recovery rates and grades, as well as high energy consumption.
A liquid alloy phase capture method is adopted, in which metallic copper or copper-based alloys are pressed into alloy blocks with carbon powder and calcium oxide, and added to molten copper smelting slag for reaction. The copper alloy captures and reduces the molten molybdenum to metallic elemental, and CaO is used to adjust the properties of the slag to achieve online separation and recovery.
In-situ capture and simultaneous enrichment of molybdenum in copper slag were achieved, with a molybdenum recovery rate of over 80%, resulting in high-grade molybdenum-containing alloys. This simplified the process and eliminated the need for crushing.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of valuable metal recycling technology, specifically relating to a method for capturing and recovering metallic molybdenum from copper smelting slag using liquid alloy phases. Background Technology
[0002] Molybdenum is one of the main copper ores. During its smelting process, molybdenum sulfide in the concentrate is oxidized to form molybdenum oxide, which enters the copper slag. However, there is little attention paid to recovering molybdenum from copper slag. This is mainly because molybdenum readily forms alloys with metallic iron and metallic copper. At 1450℃, the saturated solubility of molybdenum in iron is 20%, and the saturated solubility of molybdenum in copper is 25%. Therefore, the process of recovering molybdenum from copper slag faces the challenges of low recovery rate and complex recovery process. For the recovery of molybdenum from copper slag, Tran van Long used carbothermal reduction, but due to the low molybdenum content in copper slag and the poor selectivity of carbothermal reduction for valuable metals, the main problems were low molybdenum recovery rate and grade, and high carbon consumption and energy consumption. Huihui Zhou used crushing and grinding followed by magnetic separation to recover Mo and Cu from copper slag, but the carrier minerals had a dense structure and fine intercalation, making it difficult to fully dissociate them, resulting in low crushing efficiency and ultimately a low recovery rate. Zhang Baojing's patent used a method of co-smelting waste silicon molybdenum rods with copper slag to recover ferromolybdenum alloy, but the resulting ferromolybdenum alloy still contained some unreacted carbon and fir olivine, and had problems such as high energy consumption. In addition, the slag in the copper concentrate smelting process is in a molten state. If molybdenum can be enriched in situ from the slag at high temperature, the process flow can be significantly simplified. Summary of the Invention
[0003] To address the above problems, this invention provides a method for capturing and recovering metallic molybdenum from copper smelting slag using a liquid alloy phase.
[0004] To achieve the above objectives, the present invention adopts the following technical solution: A method for capturing and recovering metallic molybdenum from copper smelting slag using a liquid alloy phase includes the following steps: 1) Press metallic copper or copper-based alloys with carbon powder and calcium oxide into alloy blocks, add them to molten copper smelting slag for reaction. After the recovery rate of molybdenum in the copper smelting slag is greater than 80%, discharge the copper smelting slag from the slag discharge port and add a new batch of molten copper smelting slag to continue the reaction. 2) Once the molybdenum content in the alloy liquid reaches the required level, release the molybdenum-enriched alloy liquid.
[0005] Furthermore, the amount of metallic copper or copper-based alloy used is 4% to 25% of the mass of copper smelting slag.
[0006] Furthermore, the amount of carbon powder used is 1% to 15% of the mass of copper smelting slag.
[0007] Furthermore, the amount of calcium oxide used is 10% to 40% of the mass of copper smelting slag.
[0008] Furthermore, the temperature of the molten copper smelting slag is 1200 ℃~1500 ℃.
[0009] Furthermore, the reaction time is 0.5 hours to 4 hours.
[0010] Furthermore, the mass concentration of molybdenum in the resulting alloy liquid reaches 15% to 25%.
[0011] This invention addresses the problems of difficult recovery of valuable metals from smelting slag, low metal recovery rate, and low grade by providing a method for capturing and recovering metallic molybdenum from copper smelting slag using a liquid alloy phase. This invention uses a liquid copper alloy as the collector and carbon as the reducing agent. Based on the selective reduction of valuable metal oxides to elemental metals via carbothermal reduction, it utilizes the copper affinity of molybdenum to capture and reduce molybdenum and other valuable elements to elemental form using the copper alloy melt. The physicochemical properties of the slag are adjusted by adding CaO, resulting in a high-density copper-molybdenum alloy after the reaction. The alloy phase settles to the lower layer (valuable metal grade ≥ 0.5%, recovery rate ≥ 81%), achieving online separation and recovery from the slag. This enables in-situ online capture and separation of valuable elements in the slag, eliminating the need for the necessary crushing process when using cold copper slag as raw material.
[0012] The present invention has the following benefits: (1) This invention can realize in-situ capture, recovery and simultaneous enrichment of molybdenum in slag; (2) The present invention can realize the online separation of the slag and the slag to obtain a high-grade molybdenum alloy.
[0013] (3) The molybdenum recovery rate in this invention is greater than 80%, and the process is simple. It can achieve the enrichment and recovery of molybdenum in copper slag without grinding, separation and other equipment. Detailed Implementation
[0014] A method for capturing and recovering metallic molybdenum from copper smelting slag using a liquid alloy phase comprises the following steps: 1) Press metallic copper or copper-based alloy with carbon powder and calcium oxide into alloy blocks, add them to copper slag that has been finely ground and dried and molten at 1200 ℃~1500 ℃, react in a flash furnace for 0.5 hours to 4 hours, and after the recovery rate of molybdenum in the copper slag is greater than 80%, remove the slag from the slag discharge port and add a new batch of molten slag to continue the reaction; 2) Take samples from the bottom to test the content of molybdenum and other valuable metals in the alloy liquid. After the molybdenum content reaches the standard, release the alloy liquid from the bottom of the flash furnace to obtain an alloy liquid with a molybdenum content of 15% to 25%.
[0015] The amount of metallic copper or copper-based alloy used is 4% to 25% of the mass of copper smelting slag. The amount of carbon powder used is 1% to 15% of the mass of copper smelting slag. The amount of calcium oxide used is 10% to 40% of the mass of copper smelting slag.
[0016] The following are specific implementation examples based on the technical solution of this invention, which will help to better understand this invention. It should be noted that this invention is not limited to the following embodiments. Any non-substantial modifications or alterations to the form or content of this invention made by those skilled in the art based on the principles of this invention are within the scope of protection of this invention.
[0017] The main components of the copper smelting slag used in the examples, by mass percentage, include Mo 0.1%~3%, Cu 0.3%~20%, FeO 40%~60%, and SiO2 20%~40%, with the sum of their mass percentages being 100%.
[0018] Example 1: Copper smelting slag was finely ground, dried, and melted before being placed in a flash furnace. Simultaneously, 8% copper powder, 12% carbon powder, and 20% CaO by mass were pressed into lumps and added to the molten copper smelting slag at 1350℃. After reacting for 3 hours, a sample was taken and the molybdenum recovery rate in the copper smelting slag was measured to be 79.23%. The molten slag was then discharged from the slag outlet, and a new batch of molten slag was added to continue the reaction. After 5 reactions, a sample was taken from the bottom of the flash furnace and the molybdenum content in the alloy liquid was measured to be 11.34%, and the content of iron and other valuable metals was 88.66%. The alloy liquid was then discharged from the bottom to obtain a molybdenum alloy liquid.
[0019] Example 2: Copper smelting slag was finely ground, dried, and melted before being placed in a flash furnace. Simultaneously, 12% copper powder, 8% carbon powder, and 30% CaO by mass were pressed into lumps and added to the molten copper smelting slag at 1450℃. After reacting for 3 hours, a sample was taken and the molybdenum recovery rate in the copper smelting slag was measured to be 81.76%. The molten slag was then discharged from the slag outlet, and a new batch of molten slag was added to continue the reaction. After 5 reactions, a sample was taken from the bottom of the flash furnace and the molybdenum content in the alloy liquid was measured to be 14.74%, and the content of iron and other valuable metals was 85.26%. The alloy liquid was then discharged from the bottom to obtain a molybdenum alloy liquid.
[0020] Example 3: Copper smelting slag was finely ground, dried, and melted before being placed in a flash furnace. Simultaneously, 12% copper powder, 5% carbon powder, and 25% CaO by weight were pressed into lumps and added to the molten copper smelting slag (Zn: 0.39%) at 1450℃. After reacting for 3 hours, a sample was taken and the molybdenum recovery rate in the copper smelting slag was measured to be 76.34%. The molten slag was then discharged from the slag outlet, and a new batch of molten slag was added to continue the reaction. After 5 reactions, a sample was taken from the bottom of the flash furnace and the molybdenum content in the alloy liquid was measured to be 8.26%, and the content of iron and other valuable metals was 11.74%. The alloy liquid was then discharged from the bottom to obtain a molybdenum alloy liquid.
[0021] Comparative Example 1: Copper smelting slag was finely ground, dried, and melted before being placed in a flash furnace. Simultaneously, 5% of its mass of carbon powder and 25% of its mass of CaO were pressed into lumps and added to the molten copper smelting slag at 1450℃. After reacting for 3 hours, a sample was taken and the molybdenum recovery rate in the copper smelting slag was measured to be 65.23%. The molten slag was then discharged from the slag outlet, and a new batch of molten slag was added to continue the reaction. After 5 reactions, a sample was taken from the bottom of the flash furnace and the molybdenum content in the alloy liquid was measured to be 6.51%, and the content of iron and other valuable metals was 13.49%. The alloy liquid was then discharged from the bottom to obtain a molybdenum alloy liquid.
[0022] Comparative Example 2: After finely grinding and drying the copper smelting slag, it was melted and placed in a flash furnace. At the same time, 5% of the carbon powder by mass was added to the molten copper smelting slag at 1450 °C. After reacting for 3 hours, the alloy liquid and slag liquid could not be separated.
[0023] Table 1 Comparison of some parameters in the embodiments Comparative Example 1 represents the main method used in existing carbothermic reduction for recovering rare and dispersed metals from smelting slag. In this method, the addition of copper powder resulted in a higher molybdenum recovery rate than in Comparative Example 1 without copper powder. This indicates that the addition of copper powder helps lower the viscosity and melting point of the melt, increasing its fluidity and enhancing its ability to trap molybdenum. Furthermore, in this method, CaO primarily acts as a flux, reducing the system's viscosity and melting point and improving melt fluidity. Without CaO, the melt cannot form metal blocks.
[0024] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be included in the scope of the present invention.
Claims
1. A method for capturing and recovering metallic molybdenum from copper smelting slag using a liquid alloy phase, characterized in that, Includes the following steps: 1) Press metallic copper or copper-based alloys with carbon powder and calcium oxide into alloy blocks, add them to molten copper smelting slag for reaction. After the recovery rate of molybdenum in the copper smelting slag is greater than 80%, discharge the copper smelting slag from the slag discharge port and add a new batch of molten copper smelting slag to continue the reaction. 2) Once the molybdenum content in the alloy liquid reaches the required level, release the molybdenum-enriched alloy liquid.
2. The method for capturing and recovering metallic molybdenum from copper smelting slag using liquid alloy phases according to claim 1, characterized in that: The amount of metallic copper or copper-based alloy used is 4% to 25% of the mass of copper smelting slag.
3. The method for capturing and recovering metallic molybdenum from copper smelting slag using liquid alloy phases according to claim 1, characterized in that: The amount of carbon powder used is 1% to 15% of the mass of copper smelting slag.
4. The method for capturing and recovering metallic molybdenum from copper smelting slag using a liquid alloy phase according to claim 1, characterized in that: The amount of calcium oxide used is 10% to 40% of the mass of copper smelting slag.
5. The method for capturing and recovering metallic molybdenum from copper smelting slag using a liquid alloy phase according to claim 1, characterized in that: The temperature of the molten copper smelting slag is 1200 ℃~1500 ℃.
6. The method for capturing and recovering metallic molybdenum from copper smelting slag using a liquid alloy phase according to claim 1, characterized in that: The reaction time is 0.5 hours to 4 hours.
7. The method for capturing and recovering metallic molybdenum from copper smelting slag using a liquid alloy phase according to claim 1, characterized in that: The mass concentration of molybdenum in the resulting alloy liquid is 15% to 25%.