A method for regenerating lead by side-blown submerged smelting of composite iron balls

Abstract

The present invention relates to the technical field of smelting furnaces and kilns, and specifically relates to a method for side-blown submerged smelting of regenerated lead with composite iron balls. The present invention uses composite iron balls to replace iron oxide scales or hematite ores to avoid insufficient physical properties. The coke fines and anthracite in the composite iron balls generate a large amount of heat under the combustion assistance of oxygen-enriched air, contact and burn with the molten slag and undergo reduction reactions. Through solid-liquid mass transfer and heat transfer, the reaction efficiency is enhanced, the utilization rate of coal is increased, and the melting of materials is accelerated. More importantly, due to the large specific gravity of the composite iron balls, they are submerged in the molten pool under the impact of wind pressure. The coke fines in the composite iron balls preferentially and rapidly react with PbO for reduction, enhancing the reduction effect. In addition, in the present invention, there are 3 air nozzles on each of the left and right sides corresponding to the feeding area, and the diameter of 1 air nozzle is increased, enhancing the injection of oxygen-enriched air, strengthening the combustion in the feeding area, and accelerating the melting and reduction of materials; the melting and reduction effects are enhanced. At the same time, the present invention uses low-cost coke fines to replace anthracite, effectively reducing costs.

Description

Technical Field

[0001] The present invention relates to the technical field of smelting furnaces and kilns, and particularly to a method for side-blown submerged smelting of composite iron balls for regenerating lead. Background Art

[0002] Oxygen-enriched side-blown furnaces are widely used in smelting lead-containing materials such as lead paste produced by decomposing waste lead-acid batteries to produce regenerated lead. Generally, 3-5w% iron oxide scale powder or red iron ore lumps, 1.5-2w% limestone lumps as slag-forming auxiliary materials, and 10-13% anthracite lumps are added to the oxygen-enriched side-blown furnace for smelting to produce regenerated lead. Its disadvantages are as follows:

[0003] The specific gravity of anthracite is small, 0.8-1.0t / m 3 , while the density of the molten slag layer is 3.5-4.0t / m 3 . It floats on the molten slag for combustion and reduction, and the heat transfer effect of the outer flame is poor. The contact reduction efficiency of lead-containing materials and anthracite in the form of solid-solid or gas-solid is low.

[0004] 2) Deficiencies in the use of iron oxide scale powder or red iron ore lumps as auxiliary materials: The content of iron oxide scale powder is Fe60-65w%, SiO23-5w%, and moisture 8-12%. The dust during unloading and feeding of the powder is large, the high moisture causes large losses and is not conducive to slag batching; the content of red iron ore lumps is Fe50-60w%, SiO25-8w%, moisture 3-5%. The high silica content is not conducive to the flow of molten slag, and the block is dense and difficult to melt.

[0005] 3) Generally, there are 10 tuyeres in the oxygen-enriched side-blown furnace, which are distributed at intervals on the left and right in a staggered manner. There is a large amount of material in the feeding area while the tuyeres are evenly distributed, resulting in insufficient and low-efficiency spraying of oxygen-enriched air, which is not conducive to the melting and reduction of materials and affects the bed capacity per unit area.

[0006] 4) The optimal conditions for smelting lead paste in the oxygen-enriched side-blown furnace to produce regenerated lead are: the bed capacity per unit area is 80t / (m 2 .d), the single consumption of anthracite is 245Kg / t, the single consumption of iron oxide scale is 50Kg / t or the single consumption of red iron ore is 53Kg / t, the energy consumption and auxiliary material cost are 340 yuan / ton, the soot production rate is 18w%, and the sulfur dioxide concentration in the flue gas during the oxidation period is 2.5-4.5v% and it is difficult to be stable. For many years, there has been no new method to break through the above indicators. Summary of the Invention

[0007] The object of the present invention is to provide a method for smelting and recycling lead by side-blown immersion of composite iron balls. Coke fines and iron ore powder are mixed and pelletized to form composite iron balls, replacing auxiliary materials such as mill scale or hematite. The composite iron balls have a large specific gravity and are immersed in the molten pool of lead-containing materials in a oxygen-enriched side-blown furnace for smelting and recycling lead. They contact with the molten slag to carry out combustion and reduction reactions, enhancing the reaction efficiency through solid-liquid mass transfer and heat transfer, and improving the utilization rate of coal. Strengthening the oxygen-enriched air in the feeding area accelerates the melting of iron oxide and enhances the reduction of lead oxide. More importantly, the unit price of coke fines is lower than that of anthracite. While overall improving the utilization efficiency of coal and iron, it can also reduce the unit price of coal. It solves both the problems of low combustion heat transfer efficiency and poor reduction effect between lead-containing materials and anthracite, and the problems of dust and loss of mill scale and difficult melting of hematite ore. More importantly, the key indicators of smelting lead paste in an oxygen-enriched side-blown furnace to produce recycled lead have reached a new historical high.

[0008] To achieve the above object, the present invention provides the following technical solutions:

[0009] A method for smelting and recycling lead by side-blown immersion of composite iron balls, comprising:

[0010] (1) Preparing composite iron balls: 30% dry-based coke fines and 70% dry-based iron ore are mixed evenly and made into composite iron balls through the processes of pelletizing, drying, and screening;

[0011] (2) Quantitatively feeding lead-containing materials, composite iron balls, limestone blocks, and anthracite in a certain proportion, then transporting them to a mixer for mixing, and then transporting them to the top feeding port of the side-blown furnace and adding them into the molten pool of the oxygen-enriched side-blown furnace;

[0012] (3) Installing tuyeres cooled by water on both sides of the molten pool, spraying oxygen-enriched air into the interior of the molten pool. Due to the large specific gravity, the composite iron balls are immersed in the molten pool under the impact of wind pressure. Lead-containing materials such as lead paste, limestone blocks, and anthracite are mixed and piled on the surface of the molten pool due to their small specific gravity; the materials in the molten pool are divided into two stages: oxidation period smelting and reduction period smelting;

[0013] Oxidation period smelting for 6.5 - 7 hours: The coke fines in the composite iron balls and anthracite generate a large amount of heat with the help of oxygen-enriched air combustion, continuously melting the mixed materials. Most of the PbSO4 in the lead-containing materials decomposes into PbO at a temperature above 850°C; among them, the coke fines in the composite iron balls immersed in the molten pool preferentially and rapidly react with PbO for reduction. A large amount of liquid lead gathers and sinks to the bottom of the molten pool, and then flows out through the siphon channel for the refining process to produce refined lead;

[0014] Reduction period smelting for 1 - 1.5 hours, only adding anthracite without adding other materials, allowing the PbSO4 in the molten pool to further decompose. The PbO in the molten pool is strongly reduced by anthracite, forming liquid lead separated from the upper slag. After detecting the slag and sampling, when the Pb content in the upper slag is less than 1.2%, the slag discharge port is opened to discharge the slag; the molten slag is impacted by a large amount of flowing water to form small granular water-quenched slag;

[0015] (4)Control of slag type and reducing atmosphere

[0016] Insert an iron rod into the furnace to take out the slag sample, and detect the contents of Pb, FeO, SiO2, and CaO in the slag sample by X-ray fluorescence spectrometer. During the oxidation period of smelting, the control requirements are: Pb: 18 - 23%, FeO: 20 - 22%, SiO2: 19 - 21%, CaO: 8 - 11%; if not within this range, the feeding speeds of anthracite, composite iron balls, and limestone blocks should be increased or decreased for adjustment;

[0017] (5)The flue gas generated by the smelting reaction contains sulfur dioxide and soot. After dust removal and cooling, it enters the electrostatic precipitator for further dust removal, and finally enters the all-ion desulfurization and sulfuric acid production system to produce refined acid.

[0018] Preferably, in the step (1), the 30% coke fines material formula: fixed carbon ≥ 81%, volatile matter ≤ 6%, ash content ≤ 13%, water ≤ 6.5%, particle size 0 - 3mm; the 70% iron ore powder material formula: Fe ≥ 60%, SiO2 ≤ 6%, water ≤ 12%, particle size 0 - 2mm.

[0019] Preferably, in the step (1), the quality standard of the composite iron balls: spherical particle size 10 - 50mm, sieve residue ≤ 8% for particles ≤ 10mm, Fe: 42 - 45%, fixed carbon: 21 - 24%, SiO2 ≤ 5%, water ≤ 4%, specific gravity 4.5 - 5.2t / m 3 。

[0020] Preferably, in the step (2), the feeding ratio is: lead-containing material 100w%, composite iron balls 4 - 4.2w%, limestone blocks 1.6 - 1.8w%, anthracite blocks 10.5 - 11%.

[0021] Preferably, in the step (2), the feeding speed of the lead-containing waste is 46 - 60t / h, the feeding speed of the limestone blocks is 1.6 - 1.8w% of the feeding speed of the lead-containing waste, the feeding speed of the composite iron balls is 4.0 - 4.2w% of the feeding speed of the lead-containing waste, and the feeding speed of the anthracite is 11.5 - 12w% of the feeding speed of the lead-containing waste minus 28 - 30% of the feeding speed of the composite iron balls.

[0022] Preferably, in the step (3), during the oxidation period: the total amount of oxygen input is 90 - 102 Nm of the carbon content in anthracite plus the carbon content in composite iron balls 3 / kg, the number of tuyeres is 10 - 12, and the oxygen concentration is 75 - 78%; during the reduction period: the amount of anthracite is 5t / h, the number of tuyeres is 8 - 10 for oxygen, the total amount of oxygen input is 4000 Nm 3 , and the oxygen concentration is 50 - 55%.

[0023] Preferably, tuyeres A1, A2, A3, A4, A5, A6, A7, A8, A9, A10 and tuyeres B1, B2, B3, B4, B5, B6, B7, B8, B9, B10 are respectively arranged on both sides of the molten pool, where: the diameters of tuyeres A4 and B5 are 32 mm, and the diameters of the others are 30 mm; during the oxidation period, tuyeres A1, A3, A4, A5, A7, A9 and tuyeres B2, B4, B5, B6, B8, B10 are normally opened for production, the pressure is controlled at 0.09 - 0.11 MPa, and the oxygen-enriched air flow rate per single tuyere is 600 - 650 Nm3 / h; during the oxidation period smelting, 3 tuyeres are respectively arranged on the left and right corresponding to the feeding area and the diameter of 1 tuyere is increased to enhance the injection of oxygen-enriched air, strengthen the combustion in this area, and accelerate the melting and reduction of the quick materials.

[0024] Compared with the prior art, the beneficial effects of the present invention are:

[0025] 1. The composite iron balls replace iron oxide scale or red iron ore to avoid insufficient physical properties.

[0026] The composite iron balls are spherical, have high strength, are not easy to form fine powder, generate less dust during loading and unloading, and are easy to unload on the unloader with a ventilation hood, avoiding the dust of iron oxide powder and the pollution and loss caused by the loader.

[0027] 2. The composite iron balls strengthen the submerged molten pool smelting in the feeding area, and the melting and reduction effects are enhanced.

[0028] First, a large amount of heat is generated by the coke fines and anthracite in the composite iron balls with the help of oxygen-enriched air combustion, and the combustion and reduction reactions occur when contacting with the molten slag. The reaction efficiency is enhanced through solid-liquid mass transfer and heat transfer, the utilization rate of coal is improved, and the melting of the quick materials is accelerated.

[0029] Second, due to the large specific gravity, the composite iron balls are submerged in the molten pool under the impact of the wind pressure. The coke fines in the composite iron balls react with PbO for reduction preferentially and quickly, enhancing the reduction effect.

[0030] Third, 3 tuyeres are respectively arranged on the left and right corresponding to the feeding area and the diameter of 1 tuyere is increased to enhance the injection of oxygen-enriched air, strengthen the combustion in the feeding area, and accelerate the melting and reduction of the quick materials.

[0031] 3. Using low-price coke fines to replace anthracite to reduce costs.

[0032] The unit price of coke fines is 900 yuan / ton, and the unit price of anthracite is 1200 yuan / ton, with a general price difference of 300 yuan / ton; the unit prices of the composite iron balls and iron oxide scale are both 900 yuan / ton, and the relative price difference can reduce the cost by 14 yuan / ton.

[0033] All economic and technical indicators have reached new historical highs, and the comprehensive benefits are obvious.

[0034] The economic and technical indicators of the oxygen-enriched side-blown furnace smelting process for recycled lead have been significantly improved. The bed capacity per unit area has increased from 80 t / (m²·d) to 84.2 t / (m²·d), the soot production rate has decreased from 18% to 16%, and the sulfur dioxide concentration in the flue gas during the oxidation period has changed from 2.5 - 4.5% v / v to 3.5 - 4.2% v / v and is more stable.

[0035] Compared with the historical best level, the specific consumption of anthracite has decreased from 245 Kg / t to 228 Kg / t, the specific consumption of composite iron balls has increased from 50 kg / t to 59 Kg / t, the energy consumption and auxiliary material cost have decreased from 340 yuan / ton to 316 yuan / ton, with a cost reduction of 14 yuan / ton. If promoted nationwide and calculated based on 5 million tons of recycled lead, the annual cost savings can reach 70 million yuan. Description of the Drawings

[0036] Figure 1 It is a schematic diagram of the tuyere position of the present invention.

[0037] Figure 2 It is a schematic diagram of the process of the present invention.

[0038] In the figure: A1 - 10 / B1 - 10 tuyeres, C1 - C2 feeding ports, D siphon lead discharge port, E slag discharge port,

[0039] 1 - 1 lead-containing material, 1 - 2 composite iron balls, 1 - 3 limestone blocks, 1 - 4 anthracite, 2 - 1 / 2 - 2 belts, 3 cylindrical shaft mixer, 4 feeding opening, 5 side-blown furnace, 6 waste heat boiler, 7 electrostatic precipitator, 8 all-ion desulfurization and sulfuric acid production system, 9 slag discharge port, 10 siphon lead discharge port. Detailed Embodiments

[0040] To further elaborate on the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following, in combination with the drawings and preferred embodiments, details the specific embodiments, structures, features, and their effects of the present invention as follows.

[0041] As Figure 2 shown, a method for side-blown submerged smelting of recycled lead with composite iron balls includes:

[0042] 1. Preparation method and quality standards of composite iron balls

[0043] 30% dry basis coke fines and 70% dry basis iron ore are mixed evenly and made into composite iron balls through the processes of pelletizing, drying, and screening. The standards for the 70% iron ore powder materials are: Fe ≥ 60%, SiO2 ≤ 6%, water ≤ 12%, particle size 0 - 2mm. The standards for the 30% coke fines materials are: low calorific value ≥ 6100 kcal / Kg, fixed carbon ≥ 81%, volatile matter ≤ 6%, ash content ≤ 13%, water ≤ 6.5%, particle size 0 - 3mm. The quality standards for the composite iron balls are: spherical particle size 10 - 50mm, undersize material ≤ 10mm ≤ 8%, Fe: 42 - 45%, fixed carbon: 21 - 24%, SiO2 ≤ 5%, water ≤ 4%, specific gravity 4.5 - 5.2t / m 3 。

[0044] 2. Process of Side - blown Immersion Smelting of Composite Iron Balls for Recycling Lead

[0045] Lead - containing materials such as lead paste 1 - 1, composite iron balls 1 - 2, limestone blocks 1 - 3, and anthracite 1 - 4 are added according to 100w% of lead - containing materials, 4 - 4.2w% of composite iron balls, 1.6 - 1.8w% of limestone blocks, and 10.5 - 11% of anthracite blocks through a quantitative belt bunker, and then conveyed to a rotary drum mixer 3 for mixing through belt 2 - 1, then conveyed to the top feeding port of the side - blown furnace 5 through belt 2 - 2, and finally added to the molten bath of the oxygen - enriched side - blown furnace through the feeding port 4;

[0046] Air nozzles using water cooling are set on both sides of the molten bath, and oxygen - enriched air is sprayed into the molten bath. The composite iron balls, due to their large specific gravity, are immersed in the molten bath under the impact of wind pressure. Lead - containing materials such as lead paste, limestone blocks, and anthracite, due to their small specific gravity, are mixed and piled on the surface of the molten bath; The materials in the molten bath are divided into two stages: oxidation period smelting and reduction period smelting;

[0047] Oxidation period smelting for 6.5 - 7 hours: That is, the coke fines and anthracite in the composite iron balls generate a large amount of heat under the combustion support of oxygen - enriched air, continuously melting the mixed materials. Most of the PbSO4 in the lead - containing materials decomposes into PbO at temperatures above 850°C; Among them, the coke fines in the composite iron balls immersed in the molten bath preferentially and rapidly react with PbO for reduction. A large amount of liquid lead accumulates and sinks to the bottom of the molten bath, and then flows out through the siphon channel for the refining process to produce refined lead;

[0048] Reduction period smelting for 1 - 1.5 hours, that is, only anthracite is added without adding other materials, so that PbSO4 in the molten bath further decomposes. PbO in the molten bath is strongly reduced by anthracite, forming liquid lead separated from the upper slag. After slag probing and sampling, when the Pb content in the upper slag is less than 1.2%, the slag discharge port is opened to discharge the slag. The molten slag is impacted by a large amount of flowing water to form small - granular water - quenched slag;

[0049] The flue gas generated by the smelting reaction, containing sulfur dioxide and soot, is dust - removed and cooled by a vertical waste heat boiler 6, then enters an electrostatic precipitator 7 for further dust - removal, and finally enters a full - ion desulfurization and sulfuric acid production system 8 to produce refined acid;

[0050] 3. Quantitative batching and oxygen-enriched air consumption

[0051] The feeding speed of lead-containing waste such as lead paste is 46 - 60 t / h. The feeding speed of limestone blocks is 1.6 - 1.8 w% of the feeding speed of lead-containing waste. The feeding speed of composite iron balls is 4.0 - 4.2 w% of the feeding speed of lead-containing waste. The feeding speed of anthracite is 11.5 - 12 w% of the feeding speed of lead-containing waste minus 28 - 30% of the feeding speed of composite iron balls. Oxidation period: The total amount of oxygen input is 90 - 102 Nm3 / kg of the carbon content of anthracite plus the carbon content of composite iron balls. The number of tuyeres is 10 - 12, and the oxygen concentration is 75 - 78%. Reduction period: Only 5 t / h of anthracite is added, no other materials are added. The number of tuyeres is 8 - 10, and the total amount of oxygen input is about 4000 Nm3, and the oxygen concentration is 50 - 55%.

[0052] 4. Tuyere distribution method

[0053] As Figure 1 shown, A1 - 10 and B1 - 10 are tuyeres. The main function is to spray oxygen-enriched air into the molten slag layer in the furnace to assist in coal combustion. Among them: The diameters of A4 and B5 are 32 mm, and the others are 30 mm. During the oxidation period, the tuyeres A1, A3, A4, A5, A7, A9 and B2, B4, B5, B6, B8, B10 are normally opened for production, and the pressure is controlled at 0.09 - 0.11 MPa. The air volume of single-branch oxygen-enriched air is 600 - 650 Nm3 / h. During the oxidation period smelting, there are 3 tuyeres on each side corresponding to the feeding area, and the diameter of 1 tuyere is increased to enhance the injection of oxygen-enriched air, strengthen the combustion in this area, and accelerate the melting and reduction of quick materials. Especially under the action of the solid-liquid reaction of the composite iron ball immersed in the molten slag, the reaction efficiency in this area is higher.

[0054] 5. Slag type and reduction atmosphere control

[0055] Because after the composite nodular iron containing coke dust is immersed in the molten bath, its reducibility is enhanced, and over-reduction also promotes the side reaction of generating PbS, which leads to an increase in the slag content of the produced recycled lead. Therefore, it is very important to control the slag type and reduction atmosphere of the oxygen-enriched side-blowing furnace. The technical method of this technology is to insert an iron rod into the furnace to take out the slag sample, and detect the contents of Pb, FeO, SiO2, and CaO in the slag sample through an X-ray fluorescence spectrometer. During the oxidation period smelting, the control requirements are Pb: 18 - 23%, FeO: 20 - 22%, SiO2: 19 - 21%, CaO: 8 - 11%. If it is not within this range, the feeding speeds of anthracite, composite iron balls, and limestone blocks should be increased or decreased to adjust.

[0056] Experimental data:

[0057] On May 28, 2024, a batch of composite iron balls was outsourced for processing. The in-plant inspection results were as follows: undersize material through a 10 mm sieve: 7.63%, Fe: 44.2%, fixed carbon: 21.7%, SiO2: 3.2%, water: 2.4%, specific gravity 4.8 t / m 3 .

[0058] On May 29, 2024, pilot production was organized, and the situation was as follows:

[0059] During the oxidation period, materials were proportioned through a metering feeder at the rates of 58 t / h of lead paste and other lead-containing materials, 2.1 t / h of composite iron balls, 0.93 t / h of limestone blocks, and 5.93 t / h of anthracite. Production was carried out with tuyeres A1, A3, A4, A5, A7, A9 and B2, B4, B5, B6, B8, B10, controlling the pressure at 0.098 MPa, the oxygen flow rate at 5851 Nm 3 / h, and the air volume at 1224 Nm 3 / h. Samples were taken for inspection 2 hours after feeding: Pb: 19.2%, FeO: 20.1%, SiO2: 19.5%, CaO: 8.9%, S: 1.61%. After 6.5 hours of feeding, it entered the reduction period.

[0060] During the reduction period, anthracite was fed quantitatively at 5 t / h, and production was carried out with tuyeres A1, A3, A5, A7, A9 and B2, B4, B6, B8, B10, controlling the pressure at 0.092 MPa, the oxygen flow rate at 2051 Nm3 / h, and the air volume at 2421 Nm3 / h. The reduction duration was 50 minutes, and slag tapping was carried out for 40 minutes. The water-quenched slag was inspected: Pb: 0.87%, FeO: 28.3%, SiO2: 27.4%, CaO: 13.2%, S: 0.24%.

[0061] The materials fed on the same day were: 1096.2 t of lead-containing materials, 34.93 t of composite iron balls, 17.6 t of limestone blocks, and 134.9 t of anthracite. The outputs were: 591.2 t of recycled lead, 64.3 t of water-quenched slag, and 175.6 t of soot.

[0062] Compared with the prior art, the present invention avoids the deficiencies of dust and loss of iron oxide or red iron ore, improves the melting and reduction efficiency in the process of smelting recycled lead from lead paste and other lead-containing materials using an oxygen-enriched side-blown furnace, significantly improves the unit area hearth capacity, and significantly improves the cost reduction benefits of anthracite and composite iron balls. The indicators such as the soot production rate and the sulfur dioxide concentration in the flue gas are stable and improving, and are significantly better than the current industry indicators.

[0063] The above are only the preferred embodiments of the present invention and do not impose any form of limitation on the present invention. Although the present invention has been disclosed above with the preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes or modifications to equivalent embodiments by using the above-disclosed technical content without departing from the technical solution of the present invention. However, as long as it does not depart from the technical solution content of the present invention, any brief modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A method for smelting recycled lead by side-blowing immersion of composite iron balls, characterized in that: include: (1) Preparing composite iron balls, using 30% dry coke foam and 70% dry iron ore to mix evenly and then undergo ball pressing, drying and screening to make composite iron balls; the 30% coke foam material formula: fixed carbon ≥81%, volatile matter ≤6%, ash ≤13%, water ≤6.5%, particle size 0-3mm; the 70% iron ore powder material formula: Fe ≥60%, SiO2 ≤6%, water ≤12%, particle size 0-2mm; composite iron ball quality standard: spherical particle size 10-50mm, ≤10mm sieve under ≤8%, Fe: 42-45%, fixed carbon: 21-24%, SiO2 ≤5%, water ≤4%, specific gravity 4.5-5.2t / m 3 ; (2) Feeding lead-containing materials, composite iron balls, limestone blocks, and anthracite in a quantitative manner according to 100w% of lead-containing materials, 4-4.2w% of composite iron balls, 1.6-1.8w% of limestone blocks, and 10.5-11w% of anthracite blocks, and then conveying them to a mixer for mixing, and then conveying them to the feeding port at the top of the side-blowing furnace and adding them into the molten pool of the oxygen-enriched side-blowing furnace; (3) Water-cooled air nozzles are provided on both sides of the molten pool to spray oxygen-enriched air into the molten pool. Due to their high specific gravity, the composite iron balls are immersed in the molten pool under the impact of wind pressure. Lead paste and other lead-containing materials, limestone blocks, and anthracite are mixed and piled on the surface of the molten pool due to their low specific gravity. The materials are smelted in the molten pool in two stages: oxidation smelting and reduction smelting. Smelting in the oxidation period is 6.5-7 hours: the coke foam and anthracite in the composite iron balls generate a lot of heat under the combustion support of oxygen-rich air, continuously melting the mixed materials, and most of the PbSO4 in the lead-containing materials is decomposed into PbO at a temperature above 850°C; the coke foam in the composite iron balls immersed in the molten pool preferentially and rapidly reacts with PbO for reduction, and a large amount of liquid lead gathers and settles to the bottom of the molten pool, and then flows out through the siphon channel for refining process to produce refined lead; During the reduction period, the smelting is performed for 1-1.5 hours, and only anthracite is added without other materials, so that the PbSO4 in the molten pool is further decomposed. The PbO in the molten pool is intensively reduced by the anthracite to form liquid lead and separate from the upper slag. After slag sampling, if the upper slag contains less than 1.2% Pb, the slag outlet is opened to discharge the slag; the molten slag is impacted by a large amount of flowing water to form small granular water-quenched slag; (4) Slag type and reducing atmosphere control Insert an iron rod into the furnace to take out the slag probe, and use an X-ray fluorescence instrument to detect the contents of Pb, FeO, SiO2, and CaO in the slag probe. The smelting control requirements during the oxidation period are Pb: 18-23%, FeO: 20-22%, SiO2: 19-21%, and CaO: 8-11%. If they are not within this range, the feeding speed of anthracite, composite iron balls, and limestone blocks should be increased or decreased to adjust.

2. The method for smelting recycled lead by side-blowing immersion of composite iron balls as claimed in claim 1, characterized in that: In the step (2), the feed rate of lead-containing waste is 46-60 t / h, the feed rate of limestone blocks is 1.6-1.8w% of the feed rate of lead-containing waste, the feed rate of composite iron balls is 4.0-4.2w% of the feed rate of lead-containing waste, and the feed rate of anthracite is 11.5-12w% of the feed rate of lead-containing waste minus 28-30% of the feed rate of composite iron balls.

3. The method for smelting recycled lead by composite iron ball side-blowing immersion smelting as claimed in claim 1, characterized in that: In the step (3), during the oxidation period, the total amount of oxygen added is equal to the carbon content of the anthracite plus the carbon content of the composite iron ball 90-102Nm 3 / kg, the number of tuyeres is 10-12, and the oxygen concentration is 75-78%; reduction period smelting: anthracite volume 5t / h, the number of tuyeres is 8-10, and the total amount of oxygen is 4000Nm 3 , oxygen concentration 50-55%.

4. A method for smelting recycled lead by composite iron ball side-blowing immersion smelting as claimed in claim 1 or 3, characterized in that: The two sides of the molten pool are respectively provided with tuyere A1, tuyere A2, tuyere A3, tuyere A4, tuyere A5, tuyere A6, tuyere A7, tuyere A8, tuyere A9, tuyere A10 and tuyere B1, tuyere B2, tuyere B3, tuyere B4, tuyere B5, tuyere B6, tuyere B7, tuyere B8, tuyere B9, tuyere B10, among which: tuyere A4 and tuyere B5 have a diameter of 32 mm, and the others have a diameter of 30 mm; during the oxidation period, the tuyere is normally opened. A1, tuyere A3, tuyere A4, tuyere A5, tuyere A7, tuyere A9 and tuyere B2, tuyere B4, tuyere B5, tuyere B6, tuyere B8, tuyere B10 are produced, the pressure is controlled at 0.09-0.11MPa, and the air volume of a single oxygen-enriched air is 600-650Nm3 / h; during the smelting in the oxidation period, there are 3 tuyere on the left and right sides of the feeding area and the diameter of one tuyere is enlarged to enhance the injection of oxygen-enriched air, strengthen the combustion in this area, and accelerate the melting and reduction of materials.

Images