A method for efficiently recovering valuable metals from lead-zinc smelting slag

Abstract

The application discloses a method for efficiently recycling valuable metals in lead-zinc smelting slag, and comprises the following steps: the smelting slag is first subjected to a cluster bubble treatment to generate pre-cracks, and then subjected to a microwave activation treatment after filtration; the smelting slag subjected to the cluster bubble and microwave activation treatments is mixed with a reducing agent in proportion, and is sent into a side-blown reduction furnace to be smelted to obtain high-grade crude lead, slag and flue gas, and the crude lead is further refined; according to different volatilization temperatures of the valuable metals in the reduction furnace slag, the fuming furnace is subjected to sectional blowing; after the fuming furnace and the side-blown furnace flue gas are subjected to fuming, dust collection and granulation, the flue gas is returned and mixed with raw materials to form a cycle. The application overcomes the shortcomings of uneven heating, long smelting time and high energy consumption in the conventional hazardous waste slag smelting process, and has important significance for resource utilization of the hazardous waste slag.

Description

Technical Field

[0001] This invention relates to the field of solid material processing technology in metallurgy, and specifically to a method for efficiently recovering valuable metals from lead-zinc smelting slag. Background Technology

[0002] Large-scale stockpiling of lead smelting slag not only occupies vast amounts of land, but the leakage of heavy metals also poses a significant threat to the soil environment. Furthermore, lead smelting slag contains many valuable metals such as lead, zinc, and antimony, possessing high economic value. Currently, the treatment of hazardous waste slag from lead smelting involves technologies such as hydrometallurgical treatment, flotation, and pyrometallurgical treatment. Hydrometallurgical treatment generates large amounts of leachate, is time-consuming, difficult to process, and causes severe equipment corrosion. Flotation can effectively recover valuable metals such as gold and silver from smelting slag; however, since lead, zinc, and antimony in lead smelting slag mainly exist in the form of metal oxides, recovery is challenging. Pyrometallurgical treatment offers simple phase separation. However, during the roasting of smelting slag, uneven heating often leads to incomplete reduction of valuable metals, resulting in long smelting cycles and indirectly increasing energy consumption. Therefore, developing an efficient technology for treating and recovering valuable metals from hazardous waste smelting slag is an urgent problem to be solved. Summary of the Invention

[0003] The purpose of this invention is to address the shortcomings of existing technologies by providing a method for efficiently recovering valuable metals from lead-zinc smelting slag, thereby solving problems such as waste slag accumulation, high disposal costs, high technical requirements, and environmental pollution caused by the smelting process.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: using clustered bubbles generated by underwater electric spark pulse discharge to act on the surface of smelting slag, microcracks are generated on the surface and inside of the smelting slag. Under microwave field treatment, oxides such as lead and zinc in the waste slag are activated, and then oxidation smelting-fuming blowing is carried out, which shortens the reaction time.

[0005] A method for efficiently recovering valuable metals from lead-zinc smelting slag, wherein the main chemical components and mass percentages of the lead-zinc smelting slag are: lead 40.00%–60.00%, antimony 0.21%–2.00%, and zinc 10.00%–12.00%. The specific steps are as follows:

[0006] (1) The smelting slag is pretreated by using the clustered bubbles generated by underwater electric spark pulse discharge to produce pre-cracks, and then microwave activation treatment is carried out after filtration. The microwave frequency is 4GHz and the treatment time is 15-20min.

[0007] (2) After activation treatment, it is mixed with reducing agent at a ratio of smelting waste slag: semi-coke = 10:3~4 and fed into a side-blown reduction smelting furnace. Under high temperature conditions, it is smelted to obtain crude lead, side-blown slag and flue gas. The crude lead is further refined.

[0008] (3) Based on the different volatilization temperatures of lead, antimony and zinc metals in the side-blown slag, the slag produced in step (2) is sent to the fuming furnace for segmented blowing and comprehensive recovery. The temperature of the fuming furnace is 1100℃~1300℃, the blowing time is 1h~1.5h, and the flue gas temperature is 850℃~1000℃.

[0009] (4) Collect the flue gas from steps (2) and (3), cool it, collect it through a bag filter, granulate it and combine it with the raw materials, and return it to the side-blown furnace in step (2) to form a cycle. The dust removal time is 5 min to 15 min and the filtration speed is 0.25 to 0.40 m / min.

[0010] The clustered bubbles in step (1) are generated by underwater electric pulse discharge with a voltage of 200V and a current of 5-15A, and are applied 5-10 times.

[0011] The sulfur content of the semi-coke in step (2) is 0.10% to 2.00%.

[0012] In step (2), the side-blown reduction furnace uses semi-coke as fuel and reducing agent, with -0.074mm accounting for 80% to 88% and a moisture content of 0.5% to 1.2%.

[0013] In step (2), the oxygen concentration is 50% to 60%, the gas supply pressure is 0.22 to 0.28 MPa, and the calcination time is 30 min to 1 h.

[0014] The main chemical components and their mass percentages in step (2) are: lead ingot 85.00% to 97.00%, antimony 0.10% to 0.50%, and zinc 1.00% to 2.00%.

[0015] The main chemical components and mass percentages of the tailings from the side-blown furnace in step (2) are: lead 0.50%–2.00%, antimony 20.00%–40.00%, and zinc 15.00%–35.00%.

[0016] The main chemical components and their mass percentages in the tailings of the fuming furnace in step (3) are: lead 0.50% to 1.00%, zinc 1.00% to 3.00%, and antimony 0.10% to 0.40%.

[0017] The main chemical components and their mass percentages in the flue dust in step (4) are: lead 1.00% to 3.00%, antimony 0.10% to 0.50%, and zinc 3.00% to 6.00%.

[0018] The present invention has the following beneficial effects:

[0019] 1. The clustered bubbles generated by underwater electric pulses have controllable energy. For solid raw materials with hazardous waste residue properties, the action can cause micro-cracks to form inside and on the surface of the hazardous waste residue, which is conducive to the contact between the waste residue and oxygen during the subsequent roasting process and improves the reaction efficiency.

[0020] 2. Lead and zinc oxides in hazardous waste residues have good microwave absorption properties, while CaO and SiO2 have poor absorption properties. Utilizing the selective thermal effect of microwaves enhances the reduction activity of lead and zinc oxides, and the resulting thermal stress creates well-developed pores between particles, improving mass transfer and facilitating subsequent roasting and smelting, shortening reaction time, and increasing the recovery rate of valuable metals. Attached Figure Description

[0021] Figure 1 A schematic diagram of the process flow of the method of the present invention. Detailed Implementation

[0022] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. It should be understood that the described embodiments are only for illustration and explanation of the present invention and are not intended to limit the present invention.

[0023] Example 1

[0024] This embodiment is an example of a method for efficiently recovering valuable metals from lead-zinc smelting slag according to the present invention. The smelting slag comes from hazardous waste smelting slag in Guangxi, with a processing volume of 10 kg. The main chemical components and their mass percentages are: lead 48.00%, zinc 5.30%, and antimony 0.50%. The specific steps include the following:

[0025] (1) The smelting slag was first treated with clustered bubbles to produce pre-cracks, with a voltage of 200V and a current of 5A, for 5 cycles. After filtration, it was subjected to microwave activation treatment at a microwave frequency of 4GHz for 15 minutes. The main chemical components and their mass percentages were: lead 48.00%, zinc 5.30%, and antimony 0.50%.

[0026] (2) After activation treatment, the lead is mixed with a reducing agent in a certain proportion and fed into a side-blown reduction smelting furnace. Under high temperature conditions, crude lead, side-blown slag, and flue gas are obtained through smelting. The crude lead is further refined. The oxygen concentration in the side-blown reduction furnace is 50%, and the gas supply pressure is 0.22 MPa. The smelting furnace temperature is 1150℃, and crude lead is obtained. It is then electrolyzed to obtain lead ingots.

[0027] (3) Based on the different volatilization temperatures of lead, antimony, and zinc metals in the side-blown slag, the slag produced in step (2) is sent to a fuming furnace for segmented blowing and comprehensive recycling, and the blowing slag is reduced to general solid waste. The oxygen concentration is 30% and the blowing temperature is 900℃.

[0028] (4) Collect the flue gas from steps (2) and (3), cool it, collect it through a bag filter, granulate it and combine it with the raw materials, and return it to the side-blown furnace in step (2) to form a cycle.

[0029] The above test results show that the main chemical components and their mass percentages in the slag are: lead 0.50%, zinc 3.57%, antimony 0.10%; lead 0.09g, zinc 0.67g, antimony 0.02g. The flue gas contains 1.56% lead, 0.49% antimony, and 5.69% zinc; lead 0.09g, zinc 0.31g, antimony 0.03g. Electrolytic lead contains 80.51% lead, 0.14% antimony, and 2.20% zinc.

[0030] Example 2

[0031] This embodiment is another example of the method for efficiently recovering valuable metals from lead-zinc smelting slag according to the present invention. The smelting slag comes from hazardous waste smelting slag in a certain area of ​​Jiangxi Province, with a processing volume of 15 kg, containing 50.91% lead, 7.48% zinc, and 0.48% antimony. The specific steps include the following:

[0032] (1) The smelting slag is first treated with clustered bubbles to produce pre-cracks, with a voltage of 200V and a current of 5A, for 10 cycles. After filtration, it is subjected to microwave activation treatment at a microwave frequency of 4GHz for 15 minutes.

[0033] (2) After activation treatment, the lead compound is mixed with a reducing agent in a certain proportion and fed into a side-blown reduction smelting furnace. Under high temperature conditions, crude lead, side-blown slag, and flue gas are obtained through smelting. The crude lead is further refined. The oxygen concentration is 50%, and the gas supply pressure is 0.22 MPa. Lead compounds are reduced to crude lead. The smelting furnace temperature is 1200℃ to obtain crude lead, which is then electrolyzed to obtain lead ingots.

[0034] (3) Based on the different volatilization temperatures of lead, antimony, and zinc metals in the side-blown slag, the slag produced in step (2) is sent to a fuming furnace for segmented blowing and comprehensive recycling, and the blowing slag is reduced to general solid waste. The oxygen concentration is 35% and the blowing temperature is 900℃.

[0035] (4) The flue gas collected in steps (2) and (3) is cooled, then collected by a bag filter, granulated, and combined with the raw materials before being returned to the side-blown furnace in step (2) to form a cycle. The dust content is 0.04 g / m³. 3 It contains 0.40% sulfur.

[0036] The above experimental results show that the main chemical components and their mass percentages in the slag are: lead 0.59%, zinc 2.02%, antimony 0.21%; lead 111.5g, zinc 38.18g, antimony 39.7g. The main chemical components and their mass percentages in the valuable metal content of the flue gas are: lead 1.12%, antimony 0.34%, zinc 4.57%; lead 61.6g, zinc 18.7g, antimony 251.4g. In electrolytic lead, lead is 85.21%, antimony is 0.39%, and zinc is 1.61%.

[0037] Example 3

[0038] This embodiment is another example of the method for efficiently recovering valuable metals from lead-zinc smelting slag according to the present invention. The smelting waste slag is hazardous waste slag from a smelting facility in Shandong Province, with a processing volume of 10 kg. Its main chemical components and mass percentages are: lead 56.18%, zinc 10.17%, and antimony 1.52%. The specific steps include the following:

[0039] (1) The smelting slag was first treated with clustered bubbles to produce pre-cracks, with a voltage of 200V and a current of 5A, for 15 cycles. After filtration, it was subjected to microwave activation treatment at a microwave frequency of 4GHz for 15 minutes.

[0040] (2) After activation treatment, the lead is mixed with a reducing agent in a certain proportion and fed into a side-blown reduction smelting furnace. Under high temperature conditions, crude lead, side-blown slag, and flue gas are obtained through smelting. The crude lead is further refined. The oxygen concentration is 60%, and the gas supply pressure is 0.28 MPa. The furnace temperature is 1150℃, and crude lead is obtained. It is then electrolyzed to obtain lead ingots.

[0041] (3) Based on the different volatilization temperatures of lead, antimony, and zinc metals in the side-blown slag, the slag produced in step (2) is sent to a fuming furnace for segmented blowing and comprehensive recycling, and the blowing slag is reduced to general solid waste. The oxygen concentration is 20% and the smelting temperature is 900℃.

[0042] (4) Collect the flue gas from steps (2) and (3), cool it, then collect it through a bag filter, granulate it, and combine it with the raw materials. The granulated gas is then returned to the first-stage side-blowing section to form a cycle. The exhaust gas is desulfurized before being discharged. The dust content is 0.02 g / m³. 3 It contains 0.31% sulfur.

[0043] The above test results show that the main chemical components and mass percentages of the slag are: lead 0.48%, zinc 2.04%, antimony 0.37%; lead 90.7g, zinc 385.6g, antimony 69.9g. The main chemical components and mass percentages of the valuable metals in the flue gas are: lead 1.24%, antimony 0.21%, zinc 3.18%; lead 68.2g, zinc 11.6g, antimony 174.9g. The electrolytic lead contains 95.27% lead, 0.35% antimony, and 1.57% zinc.

[0044] Comparative Example 1

[0045] This embodiment is a comparative example of a method for efficiently recovering valuable metals from lead-zinc smelting slag according to the present invention. The smelting waste slag is hazardous waste slag from a smelting facility in Shandong Province. Unlike the embodiment, the hazardous waste slag in the comparative example did not undergo pretreatment with clustered bubbles and microwaves. The remaining steps are the same as in Embodiment 1. The amount of hazardous waste slag processed was 10 kg. The experimental results show that the main chemical composition and mass percentage of the lead ingot product are: lead 95.27%, antimony 0.35%, and zinc 1.57%; the main chemical composition and mass percentage of the slag are: lead 0.80%, zinc 4.21%, antimony 0.37%; lead 151.2 g, zinc 795.7 g, and antimony 64.3 g.

[0046] The experimental results show that using clustered bubbles and microwaves for pretreatment improves the treatment efficiency of smelting hazardous waste slag, reduces enterprise energy consumption, achieves a high recovery rate of valuable metals, reduces environmental pollution, and is conducive to the comprehensive recycling and utilization of resources.

Claims

1. A method for efficient recovery of valuable metals from lead-zinc smelting slag, characterized by, The main chemical components and mass percentage of lead-zinc smelting slag are: lead content 40.00%-60.00%, antimony 0.21%-2.00%, zinc 10.00%-12.00%, and the specific steps are: (1) the lead-zinc smelting slag is pre-processed by using the cluster bubble generated by underwater electric spark pulse discharge to generate pre-cracks, filtered and then subjected to microwave activation treatment, the microwave frequency is 4 GHz, and the treatment time is 15-20 min; the cluster bubble in step (1) is generated by underwater electric pulse discharge, the voltage is 200 V, the current is 5-15 A, and the action is 5-10 times; (2) after the activation treatment, the lead-zinc smelting slag is mixed with the reducing agent at a ratio of 10:3-4 and then sent into a side-blown reduction smelting furnace, under high temperature conditions, crude lead, side-blown furnace slag and flue gas are obtained, and the crude lead is further refined; the step (2) is characterized in that the lanthanum carbon contains sulfur: 0.10%-2.00%; the side-blown reduction smelting furnace in the step (2) uses the lanthanum carbon as fuel and reducing agent, -0.074 mm accounts for 80%-88%, and the water content is 0.5%-1.2%; the smelting time in the step (2) is 30 min-1 h; the main chemical components and mass percentage of the side-blown reduction smelting furnace slag in the step (2) are: lead 0.50%-2.00%, antimony 20.00%-40.00%, and zinc 15.00%-35.00%; (3) according to the different volatilization temperatures of lead, antimony and zinc metals in the side-blown furnace slag, the slag produced in the step (2) is sent into a fuming furnace for staged blowing and refining, and comprehensive recovery is performed, the fuming furnace temperature is 1100 ℃-1300 ℃, the blowing and refining time is 1 h-1.5 h, and the flue gas temperature is 850 ℃-1000 ℃; (4) the flue gas in the steps (2) and (3) is collected, cooled, collected by a bag dust collector, granulated, combined with the raw material, and returned to the side-blown reduction smelting furnace in the step (2) to form a cycle, the dust collection time is 5 min-15 min, and the filtration speed is 0.25-0.40 m / min; the main chemical components and mass percentage of the flue dust in the step (4) are: lead 1.00%-3.00%, antimony 0.10%-0.50%, and zinc 3.00%-6.00%.

2. The method for efficiently recovering valuable metals from lead-zinc smelting slag according to claim 1, characterized in that, The oxygen concentration in the step (2) is 50%-60%, and the gas supply pressure is 0.22-0.28 MPa.

3. The method for efficiently recovering valuable metals from lead-zinc smelting slag according to claim 1, characterized in that, The main chemical components and mass percentage in the step (2) are: lead ingot 85.00%-97.00%, antimony 0.10%-0.50%, and zinc 1.00%-2.00%.

4. The method for efficiently recovering valuable metals from lead-zinc smelting slag according to claim 1, characterized in that, The main chemical components and mass percentage in the fuming furnace tail slag in the step (3) are: lead 0.50%-1.00%, zinc 1.00%-3.00%, and antimony 0.10%-0.40%.

Images