A method for preparing red lead using alloy lead

Abstract

The present invention discloses a method for preparing red lead using alloy lead, and belongs to the technical field of lead-acid battery production. The present invention uses a certain amount of lead-tin-antimony alloy lead as a raw material, produces red lead by alloy lead, strictly controls the alloy melting temperature and powder making temperature during production, reduces the burn-in loss of key additive elements, and ensures that the phase of α-PbO is more than 80%, and weak alkaline water is added during granulation, so that high-efficiency granulation and uniform particles can be achieved, and then red lead is oxidized. After adding red lead in the paste stage, the present invention does not need to add tin-containing and antimony-containing compounds, so as to achieve the reduction of battery production costs from the perspective of the entire industrial chain.

Description

Technical Field

[0001] The invention belongs to the technical field of lead-acid battery production, and in particular relates to a method for preparing red lead by using alloy lead. Background Art

[0002] Red lead, with the chemical formula Pb3O4, is a key raw material in the manufacture of lead-acid batteries. It is widely used as the positive electrode active material in valve-regulated lead-acid batteries, traction batteries, stationary batteries, electric vehicle lead-acid batteries, and submarine batteries. It is often used as an additive in the production of battery positive plates, at a level of 5% to 20% by weight of the lead powder. Its primary function is to improve formation efficiency and reduce power consumption, particularly during the battery formation (internal formation) process. In addition to red lead, antimony trioxide and stannous sulfate are also crucial additives for the positive electrode. During the paste mixing stage, they are added in proportion to the weight of the lead powder, followed by stirring for uniform addition.

[0003] The processing method of red lead is relatively mature. At present, electrolytic lead is basically used to prepare red lead. One typical production method is: electrolytic lead is heated and melted in a lead melting furnace to become liquid. The lead liquid flows into a powder making furnace in a closed pipe and then undergoes primary oxidation using the Barton powder production method. The powder after primary oxidation is then crushed and screened to obtain irregular lead oxide powder. The powder is transported to a granulator by an auger for granulation. After screening, spherical particles with basically similar particle sizes are obtained, with a diameter of about 1.0 to 2.0 mm. Finally, the powder flows into a multi-stage oxidation furnace for heating and oxidation. After cooling and testing, it is crushed and packaged to obtain red lead for production. At present, most red lead is prepared using electrolytic lead, with a lead content of 99.994%. In order to improve production efficiency, red lead companies will increase the temperature of the lead pot to over 500°C, reaching 530°C, which will increase fluidity and oxidation efficiency. Electrolytic lead will be prepared into powder through a powder making furnace at a temperature exceeding 488°C. At this temperature, the main phase of the powder is β-PbO. However, 90% of the β-PbO prepared by electrolytic lead will be converted into α-PbO after adding water. This is very critical. Only when it is converted into α-PbO can granulation be completed.

[0004] In the battery recycling system, after used batteries are recycled and smelted, valuable elements like tin and antimony need to be extracted. On the battery manufacturing side, tin and antimony need to be added to the battery in the form of compounds because they critically impact battery performance. From the recycling side, the internal metal elements can be recovered, but this requires complex impurity removal and purification techniques, increasing recycling costs. During the battery production process, antimony trioxide and stannous sulfate are affected by metal price fluctuations, especially tin, leading to higher battery manufacturing costs. Both extraction at the recycling end and addition at the manufacturing end result in increased battery production costs.

[0005] For example, patent application publication number CN102306856A discloses a method for recycling waste lead-acid batteries: waste lead-acid batteries are cut, crushed and sorted to separate waste electrolyte, plastic, lead nails and lead blocks, and lead paste; the waste electrolyte is filtered through precipitation to produce concentrated sulfuric acid; the lead nails and lead blocks are melted at low temperature and then antimony, tin and selenium are added to the melt as needed to produce a lead-based alloy; the lead paste is directly used to prepare yellow lead or red lead at low temperature.

[0006] The most prominent problem with using refined lead or lead alloys to produce red lead is the inability to complete granulation. Using powder oxidation can cause the powder to clog the multi-stage oxidation furnace, preventing the subsequent oxidation process from proceeding. Summary of the Invention

[0007] Based on the shortcomings of the existing technology, the applicant, starting from the entire lead recycling industry chain, proposed that if the electrolytic lead used in red lead production is replaced with a lead alloy rich in a certain amount of lead, tin, and antimony, red lead can be produced from the alloyed lead. The key additive elements are present in the red lead in the form of oxides. After the red lead is added in the paste stage, there is no need to add tin- and antimony-containing compounds. This can achieve a reduction in battery production costs from the perspective of the entire industry chain. Therefore, the present invention proposes a method for preparing red lead using alloyed lead, thereby reducing battery production costs from the perspective of the industry chain.

[0008] The technical solutions of the present invention are as follows:

[0009] The present invention provides a method for preparing red lead using alloy lead, wherein the alloy lead is recovered from lead-acid batteries, and the red lead is used as an additive for positive plates in lead-acid batteries. The method comprises the following steps:

[0010] (1) In the lead battery recycling process, during the lead recovery and smelting stage, tin and antimony are not removed, and a lead-tin-antimony ternary alloy is prepared through impurity removal and purification processes, wherein the tin content is 0.5% to 6.5% and the antimony content is 1.0% to 2.0%;

[0011] (2) melting the lead-tin-antimony ternary alloy obtained in step (1) into a liquid state at a melting temperature of 440° C. to 460° C.;

[0012] (3) pulverizing the liquid lead-tin-antimony ternary alloy obtained in step (2) to obtain a powder, wherein the temperature is controlled at 440° C. to 480° C. during the pulverizing process;

[0013] (4) granulating the powder obtained in step (3) to obtain granules;

[0014] (5) The particles obtained in step (4) are heated and oxidized to obtain the red lead.

[0015] Specifically, in step (1), the ratio of lead, tin and antimony in the lead-tin-antimony ternary alloy is controlled according to the formula for preparing the positive plate of the lead-acid battery; or, the ratio of lead, tin and antimony in the lead-tin-antimony ternary alloy is not controlled, and when preparing the positive plate of the lead-acid battery, the red lead is only added as part of the formula.

[0016] In a specific embodiment of the present invention, the ratio of lead, antimony, and tin in the lead-tin-antimony ternary alloy is 97.4:1.9:0.7, but the present invention is not limited thereto.

[0017] Preferably, in step (2), the melting temperature is 440°C.

[0018] Preferably, in step (3), the temperature is controlled at 440°C to 460°C during the powder making process.

[0019] After passing through the pulverizing furnace, the main phase of the powder is β-PbO (the same phase is also present when the raw material is electrolytic lead). However, after adding water to this powder, the phase conversion rate is extremely low, with only about 10% of the powder converting to α-PbO, while the majority remains β-PbO. Granulation using this powder is relatively loose. If the pulverizing furnace prevents the powder from converting to β-PbO and the majority remains α-PbO, granulation can be completed normally. It was found that by controlling the pulverizing temperature within the range of 440°C to 480°C, the main phase of the powder is α-PbO, and granulation can be completed normally.

[0020] Specifically, in step (3), a powder making furnace is used for powder making, and the powder making furnace is preheated before the liquid lead-tin-antimony ternary alloy flows in. The preheating temperature is set to 450°C. The powder making furnace does not need to be heated during the powder making stage, and the temperature in the powder making furnace is controlled within the powder making temperature range during the powder making process.

[0021] During the powder making process, the temperature of the powder making furnace is controlled by controlling the speed of the air supply; when the temperature of the powder making furnace cannot be controlled by controlling the speed of the air supply, the speed at which the liquid lead-tin-antimony ternary alloy flows into the powder making furnace is reduced.

[0022] Preferably, in step (4), the particle size of the granules obtained by granulation is 1-2 mm.

[0023] Preferably, in step (4), water is added to the powder during granulation, and the mass of the added water is controlled to be 4% to 6% of the mass of the powder; and the pH value of the water is controlled to be 7 to 8.

[0024] The main phase of the powder produced is α-PbO. When granulating, if pure water with a pH of 6-7 is used, the strength is not ideal. The resulting particles are weak and relatively uneven in size. If the weak powder breaks in the inverted heating furnace, it will become powder, blocking the furnace and preventing further powder feeding. Here, the inventors adopted the idea of using weak alkaline water and found that using weak alkaline water increased the strength of the particles and made the particles more uniform in size.

[0025] Specifically, in step (5), a multi-stage oxidation furnace is used for heating and oxidation, and the multi-stage oxidation furnace is divided into a first temperature zone, a second temperature zone, a third temperature zone and a fourth temperature zone from top to bottom. The particles pass through the first temperature zone, the second temperature zone, the third temperature zone and the fourth temperature zone in sequence, and air is introduced simultaneously.

[0026] The temperatures of the first, second, third and fourth temperature zones are 105°C to 120°C, 200°C to 300°C, 480°C to 500°C and 400°C to 460°C respectively. The above are temperature tolerances, which control the temperature. The upper and lower temperature limits are set within this range.

[0027] In step (5), the product oxidized in the multi-stage oxidation furnace is cooled, and then crushed and sieved to obtain the red lead.

[0028] Beneficial effects of the present invention:

[0029] This invention uses a lead alloy containing a certain amount of lead, tin, and antimony as raw material to produce red lead. During production, the alloy's melting and pulverizing temperatures are strictly controlled to reduce burnout of key additive elements while ensuring an a-PbO phase concentration of over 80%. The addition of weakly alkaline water during granulation enables efficient granulation with uniform particles, which are then oxidized to produce red lead. This invention eliminates the need to add tin- and antimony-containing compounds after adding red lead to the paste, thereby reducing battery production costs across the entire supply chain. DETAILED DESCRIPTION

[0030] Example 1

[0031] (1) Lead, tin and antimony ternary alloy

[0032] Waste batteries are recycled and crushed to obtain lead paste, grids and plastics. The lead paste and grids are smelted and purified to remove impurities to obtain reduced lead. The element ratio is controlled and enriched to obtain an alloy with the element composition of 97.4% Pb-1.9% Sb-0.7% Sn.

[0033] (2) Alloy melting

[0034] The prepared alloy lead ingots are sent to the lead melting furnace through a conveyor belt for melting. The melting furnace is heated to 440°C. After the alloy lead bars are added, the temperature drops and the lead melting furnace begins to heat up. The process temperature is controlled. The lead melting process is divided into the following two temperature conditions:

[0035] (2.1) Control the process temperature not to exceed 460℃ and the final temperature to be maintained at 450℃.

[0036] (2.2) Control the process temperature to be in the range of 460℃~480℃, and finally maintain the temperature at 480℃.

[0037] The alloy lead was melted into liquid, and the lead liquid was stirred. Lead ingots were sampled from three different positions of the lead pot for alloy spectral analysis. Among them, those taken out at the temperature condition (2.1) were named lead furnace 1#, 2# and 3#, and those taken out at the temperature condition (2.2) were named lead furnace 4#, 5# and 6#. The burnout of alloy elements was confirmed, as shown in Table 1.

[0038] Table 1

[0039] Lead ingot sample Pb% Sb% Sn% Lead alloy 97.4012 1.8794 0.7193 Lead Furnace 1# 97.3954 1.8655 0.7391 Lead Furnace 2# 97.4014 1.8243 0.7743 Lead Furnace 3# 97.4317 1.8421 0.7262 Lead furnace 4# 97.5508 1.7945 0.6547 Lead furnace 5# 97.5780 1.7731 0.6489 Lead furnace 6# 97.5642 1.7945 0.6413

[0040] Analysis of the spectral results in Table 1 shows that, under temperature condition (2.1), after the alloy lead strip was melted, within the temperature control range, no significant element loss occurred, remaining essentially unchanged from the alloy lead strip. Compared to temperature condition (2.1), under temperature condition (2.2), both Sb and Sn exhibited varying degrees of loss, with Sn experiencing more severe loss. Consequently, the content of key elements in the subsequently prepared red lead would not meet requirements. Therefore, the process temperature was controlled to not exceed 460°C, with the final temperature maintained at 450°C for subsequent experiments.

[0041] Example 2

[0042] The pulverizing furnace is preheated, the temperature in the furnace is maintained at 450°C, the high-speed centrifugal stirring rotation (200r / m) is turned on, the negative wind pressure is turned on, the lead liquid prepared under the temperature condition (2.1) in Example 1 is selected, and it begins to flow into the pulverizing furnace. At the same time, air is introduced at a rate of 10L / min. The temperature in the furnace begins to gradually rise, and the temperature reaches 460°C. Air is introduced at a rate of 12L / min. The temperature continues to rise, and the air introduction rate is continued to increase to 13L / min. The temperature in the furnace is maintained in the range of 440°C to 460°C, and the flow rate of the lead liquid is maintained. The powder obtained after primary oxidation in the pulverizing furnace is irregular lead oxide powder.

[0043] The irregular lead oxide powder was crushed and then screened through a secondary cyclone separator and a bag filter duct to obtain a lead oxide powder free of obvious large lumps. The powder was then collected in a powder silo. After cooling, it was passed through a 200-mesh sieve. Three samples were taken, chronologically from the powder silo, for XRD analysis. These samples were designated 7#, 8#, and 9#, with 7# being the first sample fed and 9# being the last. The test results are shown in Table 2.

[0044] Table 2

[0045] Lead ingot sample α-PbO% β-PbO% Pb% <![CDATA[Pb3O4%]]> 7# 85.3 7.7 4.3 2.7 8# 86.2 7.4 3.8 2.6 9# 84.4 7.8 4.1 3.7

[0046] After XRD test, the powder was found to be mainly composed of α-PbO, and the contents of the other three components were controlled at a low level, all within 10%, and the contents of the three samples remained basically close.

[0047] The subsequent powder passed through the auger device and flowed into the granulator for granulation. The pH value of the water was adjusted to control the range of 7-8. The measured pH value was 7.00. The water flow rate was controlled and the amount of water was added at 5%. Granulation began. After screening, the powder was successfully granulated and the particle size range was controlled within

[0048] Example 3

[0049] The powder prepared in Example 2 was selected and passed through an auger device into a granulator for granulation. The pH value of the water was adjusted to be within the range of 7-8. The measured pH value was 8.00, which was weakly alkaline. The water flow rate was controlled and 5% of water was added to start granulation. After screening, the powder was successfully granulated and the particle size range was controlled within

[0050] Example 4

[0051] The powder prepared in Example 2 was selected and passed through an auger device into a granulator for granulation. The pH value of the water was adjusted to be in the range of 8-9. The measured pH value was 8.51, alkaline. The water flow rate was controlled and 5% of water was added to start granulation. After screening, the powder could be granulated and the particle size range was controlled within However, the strength of the particles is significantly lower than that of Example 2. During the screening stage, the particles produced crack to varying degrees, which is not conducive to subsequent production processes.

[0052] Example 5

[0053] The powder prepared in Example 2 was selected and passed through an auger device into a granulator for granulation. The pH value of the water was adjusted to be within the range of 6-7. The measured pH value was 6.77, which was weakly acidic. The water flow rate was controlled and 5% of water was added to start granulation. After screening, the powder could be granulated and the particle size range was controlled within However, the strength of the particles is significantly lower than that of Example 2. During the screening stage, the particles produced crack to varying degrees, which is not conducive to subsequent production processes.

[0054] Example 6

[0055] The pulverizing furnace is preheated, the temperature in the furnace is maintained at 450°C, the high-speed centrifugal stirring rotation (200r / m) is turned on, the negative wind pressure is turned on, the lead liquid prepared under the temperature condition (2.1) in Example 1 is selected, and it begins to flow into the pulverizing furnace. At the same time, air is introduced at a rate of 10L / min, and the temperature in the furnace begins to gradually rise. The temperature reaches 460°C. Air is introduced at a rate of 12L / min, and the temperature continues to rise. The temperature in the furnace is maintained in the range of 460°C to 480°C, and the flow rate of the lead liquid is maintained. The powder obtained after primary oxidation in the pulverizing furnace is irregular lead oxide powder.

[0056] The irregular lead oxide powder was crushed and then screened through a secondary cyclone separator and a bag filter duct to obtain a lead oxide powder free of obvious large lumps. The powder was then collected in a powder silo. After cooling, it was passed through a 200-mesh sieve. Three samples were taken, chronologically from the powder silo, for XRD analysis. These samples were designated 10#, 11#, and 12#, with 10# being the first sample fed and 12# being the last. The test results are shown in Table 3.

[0057] Table 3

[0058] Lead ingot sample α-PbO% β-PbO% Pb% <![CDATA[Pb3O4%]]> 10# 80.9 10.7 4.7 3.7 11# 81.3 10.4 4.6 3.7 12# 81.7 10.2 4.9 3.2

[0059] After XRD results detection, the measured powder is mainly composed of α-PbO, and the contents of the other three components are controlled at a low level, but the β-PbO content exceeds 10%, and the contents of the three samples remain basically close.

[0060] The subsequent powder passed through the auger device and flowed into the granulator for granulation. The pH value of the water was adjusted to control the range of 7-8. The measured pH value was 7.00, which was weakly alkaline. The water flow rate was controlled and 5% of water was added to start granulation. After screening, the powder was successfully granulated and the particle size range was controlled within However, compared with Example 2, within the same production shift, by counting the weight of the granulation ton bag belts, the production efficiency of the granulation stage decreased by about 10%.

[0061] Example 7

[0062] The pulverizing furnace is preheated, the temperature in the furnace is maintained at 480°C, the high-speed centrifugal stirring rotation (200r / m) is turned on, the negative wind pressure is turned on, the lead liquid prepared under the temperature condition (2.1) in Example 1 is selected, and it begins to flow into the pulverizing furnace. At the same time, air is introduced at a rate of 10L / min. The temperature in the furnace begins to rise rapidly, and the temperature reaches 500°C. Air is introduced at a rate of 12L / min. The temperature continues to rise, and the air introduction rate is continued to increase to 13L / min. The temperature in the furnace is maintained in the range of 510°C to 520°C, and the flow rate of the lead liquid is maintained. The powder obtained after primary oxidation in the pulverizing furnace is irregular lead oxide powder.

[0063] The irregular lead oxide powder was crushed and then screened through a secondary cyclone separator and a bag filter duct to obtain a lead oxide powder free of obvious large lumps. The powder was then collected in a powder silo. After cooling, it was passed through a 200-mesh sieve. Three samples were taken, chronologically from the powder silo, for XRD analysis. These samples were designated 13#, 14#, and 15#, with 13# being the first sample fed and 15# being the last. The test results are shown in Table 4.

[0064] Table 4

[0065] Lead ingot sample α-PbO% β-PbO% Pb% <![CDATA[Pb3O4%]]> 13# 52.3 37.2 4.5 6.0 14# 48.6 40.3 4.8 6.3 15# 45.3 44.6 4.9 5.2

[0066] After XRD results detection, the measured powder phase composition has changed significantly compared with Example 2, the β-PbO content has increased significantly, and the contents of the three samples also have significant differences. The 15# sample that entered the powder bin last has the highest β-PbO content.

[0067] Subsequently, the powder passed through the auger device and flowed into the granulator for granulation. The pH value of the water was adjusted and controlled within the range of 7-8. The actual pH value was 7.00, which was weakly alkaline. The water flow rate was controlled and 5% of water was added to start granulation. After screening, the powder was granulated, but the sizes of the particles were different. After measurement, the largest particle size reached 3.5mm and the smallest particle size was only 0.8mm, which did not meet the requirements of subsequent process production. The pH value of the water was adjusted and the actual pH value was 8.00. The powder was granulated, but the sizes of the particles were still different, which was not conducive to subsequent process production.

[0068] Example 8

[0069] The pulverizing furnace is preheated, the temperature in the furnace is maintained at 500°C, the high-speed centrifugal stirring rotation (200r / m) is turned on, the negative wind pressure is turned on, the lead liquid prepared under the temperature condition (2.1) in Example 1 is selected, and it begins to flow into the pulverizing furnace. At the same time, air is introduced at a rate of 10L / min. The temperature in the furnace begins to rise rapidly, and the temperature reaches 510°C. Air is introduced at a rate of 12L / min. The temperature continues to rise, and the air introduction rate is continued to increase to 13L / min. The temperature in the furnace is maintained in the range of 520°C to 540°C, and the flow rate of the lead liquid is maintained. The powder obtained after primary oxidation in the pulverizing furnace is irregular lead oxide powder.

[0070] The irregular lead oxide powder was crushed and then screened through a secondary cyclone separator and a bag filter duct to obtain a lead oxide powder free of obvious large lumps. The powder was then collected in a powder silo. After cooling, it was passed through a 200-mesh sieve. Three samples were taken, chronologically from the powder silo, for XRD analysis. These samples were designated 16#, 17#, and 18#, with 16# being the first sample fed and 18# being the last. The test results are shown in Table 5.

[0071] Table 5

[0072] Lead ingot sample α-PbO% β-PbO% Pb% <![CDATA[Pb3O4%]]> 16# 15.4 77.6 3.7 3.3 17# 16.1 78.1 3.6 2.2 18# 15.9 79.2 3.1 1.8

[0073] After XRD results detection, the measured powder phase composition is mainly composed of β-PbO content, and the content of the three samples is basically close.

[0074] Subsequently, the powder passed through the auger device and flowed into the granulator for granulation. The pH value of the water was adjusted to control the range of 7-8. The actual pH value was 7.00, which is weakly alkaline. The water flow rate was controlled, and 5% of water was added to start granulation. After screening, the powder was completely unable to be granulated and was in a loose state. The pH value of the water was adjusted, and the actual pH value was 8.00, but granulation was still impossible.

[0075] Example 9

[0076] After preheating the pulverizing furnace, the temperature inside the furnace was maintained at 480°C. High-speed centrifugal stirring and rotation (200 rpm) was started, and negative air pressure was turned on. The lead liquid prepared under the temperature condition (2.1) in Example 1 was selected and began to flow into the pulverizing furnace. At the same time, air was introduced at a rate of 10 L / min. The temperature inside the furnace began to rise rapidly, reaching 500°C. Air was introduced at a rate of 12 L / min, and the temperature continued to rise. The temperature inside the furnace was maintained in the range of 500°C to 520°C. The air introduction rate was further increased to 14 L / min, and the temperature inside the furnace was maintained in the range of 480°C to 500°C. The air introduction rate was further increased to 16 L / min, and the temperature inside the furnace was maintained in the range of 460°C to 480°C. Within this temperature range, the flow rate of the lead liquid was maintained, and the powder obtained after primary oxidation in the pulverizing furnace was irregular lead oxide powder.

[0077] The irregular lead oxide powder was crushed and then screened through a secondary cyclone separator and a bag filter duct to obtain a lead oxide powder free of obvious large lumps. The powder was then collected in a powder silo. After cooling, it was passed through a 200-mesh sieve. Three samples were taken, chronologically from the powder silo, for XRD analysis. These samples were designated 19#, 20#, and 21#, with 19# being the first sample fed and 21# being the last. The test results are shown in Table 6.

[0078] Table 6

[0079]

[0080]

[0081] The XRD results show that the measured powder phase composition is close to that of Example 6. The content of β-PbO increases slightly due to the increase in temperature in the early stage, and the contents of the three samples are also close.

[0082] The subsequent powder passed through the auger device and flowed into the granulator for granulation. The pH value of the water was adjusted to control the range of 7-8. The measured pH value was 7.00, which was weakly alkaline. The water flow rate was controlled and 5% of water was added to start granulation. After screening, the powder was successfully granulated and the particle size range was controlled within Compared with Example 2, the production efficiency of the granulation stage decreased by about 2%.

[0083] Example 10

[0084] In Example 2, the qualified particles were heated and oxidized in a multi-stage oxidation furnace. The oxidation furnace was divided into a first temperature zone, a second temperature zone, a third temperature zone, and a fourth temperature zone starting from the top feed port. After the powder passed through the first temperature zone, it was gradually squeezed into the second temperature zone, the third temperature zone, and the fourth temperature zone under the gravity of the subsequent powder feed.

[0085] In the first temperature zone, the temperature is controlled within the range of 105°C to 110°C, and air is introduced simultaneously at a rate of 6L / min for drying pretreatment;

[0086] The second temperature zone is controlled at a temperature range of 280°C to 300°C, and air is introduced simultaneously at a rate of 8L / min. During this stage, the spherical particles become stronger and harder.

[0087] The third temperature zone is controlled at a temperature range of 485°C to 500°C, and air is introduced simultaneously at a rate of 14L / min. During this stage, lead oxide is oxidized to lead tetroxide.

[0088] The fourth temperature zone is controlled at a temperature range of 400°C-420°C, and air is introduced simultaneously at a rate of 12L / min;

[0089] The oxidized red lead is cooled and flows into a grinder for crushing. The crushed red lead powder is screened through a 200-mesh sieve. The finished product obtained by screening is transported to a storage bin through a secondary cyclone separator and a bag dust collector pipeline for testing. The red lead content is found to be 90.7%.

Claims

1. A method for preparing red lead using alloy lead, wherein the alloy lead is recovered from lead-acid batteries, and the red lead is used as an additive for positive plates in lead-acid batteries, characterized in that: The method comprises the following steps: (1) In the lead battery recycling process, during the lead recovery and smelting stage, tin and antimony are not removed, and a lead-tin-antimony ternary alloy is prepared through impurity removal and purification processes. (2) Melting the lead-tin-antimony ternary alloy obtained in step (1) into a liquid state at a melting temperature of 440°C to 460°C (3) pulverizing the liquid lead-tin-antimony ternary alloy obtained in step (2) to obtain a powder, wherein the temperature is controlled at 440° C. to 480° C. during the pulverizing process; (4) granulating the powder obtained in step (3) to obtain granules; (5) The particles obtained in step (4) are heated and oxidized to obtain the red lead.

2. The method for preparing red lead using alloy lead according to claim 1, characterized in that: In step (1), the ratio of lead, tin and antimony in the lead-tin-antimony ternary alloy is controlled according to the formula when preparing the positive plate of the lead-acid battery; alternatively, the ratio of lead, tin and antimony in the lead-tin-antimony ternary alloy is not controlled, and when preparing the positive plate of the lead-acid battery, the red lead is only added as part of the formula.

3. The method for preparing red lead using alloy lead according to claim 1, characterized in that: In step (2), the melting temperature is 440°C.

4. The method for preparing red lead using alloy lead according to claim 1, characterized in that: In step (3), the temperature is controlled at 440°C to 460°C during the powder making process.

5. The method for preparing red lead using alloy lead according to claim 1, characterized in that: In step (3), a powder making furnace is used for powder making. The powder making furnace is preheated before the liquid lead-tin-antimony ternary alloy flows in. The preheating temperature is set to 450°C. The powder making furnace does not need to be heated during the powder making stage, and the temperature in the powder making furnace is controlled within the powder making temperature range during the powder making process.

6. The method for preparing red lead using alloy lead according to claim 5, characterized in that: During the pulverizing process, the temperature of the pulverizing furnace is controlled by controlling the speed of the air supply; when the temperature of the pulverizing furnace cannot be controlled by controlling the speed of the air supply, the speed at which the liquid lead-tin-antimony ternary alloy flows into the pulverizing furnace is reduced.

7. The method for preparing red lead using alloy lead according to claim 1, characterized in that: In step (4), the particle size of the granules obtained by granulation is 1-2 mm.

8. The method for preparing red lead using alloy lead according to claim 1, characterized in that: In step (4), water is added to the powder during granulation, and the mass of the added water is controlled to be 4% to 6% of the mass of the powder; The pH value of water is controlled at 7-8.

9. The method for preparing red lead using alloy lead according to claim 1, characterized in that: In step (5), a multi-stage oxidation furnace is used for heating and oxidation. The multi-stage oxidation furnace is divided into a first temperature zone, a second temperature zone, a third temperature zone and a fourth temperature zone from top to bottom. The particles pass through the first temperature zone, the second temperature zone, the third temperature zone and the fourth temperature zone in sequence, and air is introduced simultaneously. The temperatures of the first temperature zone, the second temperature zone, the third temperature zone and the fourth temperature zone are 105°C to 120°C, 200°C to 300°C, 480°C to 500°C and 400°C to 460°C respectively.

10. The method for preparing red lead using alloy lead according to claim 9, characterized in that: In step (5), the product oxidized in the multi-stage oxidation furnace is cooled, and then crushed and sieved to obtain the red lead.

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