Method for treating lead sulfate slag through base hydrogen direct reduction process

Abstract

The invention relates to a method for treating lead sulfate slag through a base hydrogen direct reduction process. The method comprises the following process steps that (1) the lead slag enters a pretreatment drying system through a feeding system to be dried and then is put into a hydrogen reduction smelting reaction furnace; (2) valuable components such as lead sulfate and lead chloride in the lead sulfate are directly reduced into crude lead in one step; (3) adding coke and caustic soda flakes into the crude lead, and further treating to obtain products A and B; (4) after the product A passes through an ingot casting system, preparing a lead ingot containing more than 99% of lead for sale; (5) the obtained product B is high-zinc alkaline residues, and part of the high-zinc alkaline residues enter a rotary kiln or a wastewater treatment system to replace caustic soda flakes to adjust the PH value; and the other part of high-zinc alkaline residues enter a second-section vacuum distillation furnace and are continuously treated, and zinc ingots containing more than 99% of zinc are generated from the obtained product through an ingot casting system and are sold. Compared with other methods or equipment, the method is more environmentally friendly and more energy-saving, cyclic utilization is facilitated, and the utilization efficiency is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of metallurgical smelting, and particularly relates to a method for treating lead sulfate slag by alkali hydrogen direct reduction process. BACKGROUND

[0002] At present, there are fire process and wet process for treating zinc smelting lead sulfate concentrate, lead acid battery lead sulfate paste recovery or other lead sulfate hazardous waste materials. The fire treatment method mainly includes sintering / roasting-air blast furnace reduction smelting method, oxygen bottom blowing direct lead smelting method (QSL method), Outokumpu smelting method, top blowing converter smelting method (TBRC method) and Sirosmelt lead smelting method. The above methods have respective characteristics.

[0003] The air blast furnace lead smelting technology is widely used in waste lead acid battery recovery, such as Japan's Takehara Smelter, Britain's British Lead Company and Denmark's Paul Bergsol and Son Konzem Company. The waste lead acid battery lead paste needs to be mixed with air blast furnace water quenching slag, returned powder, pyrite cinder and coke powder to prepare sintered blocks by sintering, and the sintered blocks are smelted in the air blast furnace. The reverberatory furnace lead smelting can treat powdered or blocky lead-containing waste materials with or without the addition of reducing agents, and has simple operation and strong adaptability. Iron filings and soda are added during smelting to improve the smelting effect. When 5% of Na2CO3 is added to the smelting system, 77.5% of lead-containing waste paste can be reduced at 1100 DEG C for 1 h to obtain 99.9% of crude lead, and the lead recovery is 93~98%, and the smelting temperature is also reduced by 200~300 DEG C.

[0004] The electric furnace smelting does not use coke or coal as heat supply, and the coke is only used as a reducing agent, so the proportioning is low. The amount of flue gas generated during the smelting process is small, so the flue gas purification is simple, and the environmental pollution is also limited. The smelting temperature is relatively agile, so the temperature control is stable. The electric furnace smelting technology is more suitable for application in areas with sufficient electricity. The short kiln can perform two-stage smelting in the same short kiln when treating lead-containing waste materials. The first stage smelting is performed at 800 DEG C, and the antimony and lead oxide in the waste lead acid battery are reduced to smelt 40% of crude lead, and the lead content in the formed crude lead is 99.5%, and the antimony content is 0.2%. After adding coke and sodium carbonate, the second stage reduction smelting is performed at 1100~1200 DEG C, and 95.3% of lead-containing lead-antimony alloy and 3~4.5% of antimony content are obtained, and 3~4% of lead-containing slag can be further treated by the air blast furnace, and the smoke dust is returned to the short kiln for smelting.

[0005] The process flow for treating lead-containing materials in copper smelting using oxygen-enriched side-blown blast furnace technology is as follows: Lead-containing materials are leached with oxygen pressure acid to remove arsenic and zinc; the leaching residue is used for brick making; and oxygen-enriched side-blown blast furnace smelting produces lead-bismuth alloy, copper slag, and waste residue. The generated dust is collected and returned to the batching process. The furnace has a hearth area of ​​5 m², an annual processing capacity of 75,000 tons, a coal blending rate of 8%, a lime content of 8-10%, a slag ratio of 60%, a dust content of 2-3%, a lead recovery rate of 90%, and a processing cost of 600-700 yuan / ton of slag.

[0006] Bottom-blown oxidation furnaces are used to treat lead sulfate slag (containing 50-60% lead) to produce liquid high-lead slag (containing 30-85% PbO). A second step involves using a bottom-blown reduction furnace to directly reduce the high-lead slag to produce crude lead, with a crude lead recovery rate >98% and a final slag lead content <2.5%. Wet processes for treating lead sulfate slag mainly include chlorination leaching-electrowinning, slurry electrolysis combined with solid-phase electrolysis, and desulfurization-free short-process conversion and regeneration. Other wet methods include sodium hydroxide alkaline leaching-suspension electrolysis, inorganic ammonia leaching, organic amine leaching, and carbonate conversion-acid leaching. However, these methods are all based on leaching in an alkaline medium and have low equipment requirements; however, they have high energy consumption, large reagent consumption, and are prone to producing hydrofluoric acid during electrolysis. Furthermore, the amine solution is easily contaminated during the reaction, leading to degradation. The degradation products are usually corrosive, limiting the application of amine leaching. Alternatively, the leaching process can easily produce ammonia gas leakage, resulting in a poor operating environment.

[0007] The main processes for preparing lead ingots from lead slag include: chlorination leaching of lead slag, zinc replacement of the leaching solution, and sponge lead smelting. Lead slag is leached with a mixture of sodium chloride and calcium chloride, causing lead to form a complex with chloride ions that enters the leaching solution, while sulfate ions combine with calcium and precipitate into the leaching residue. The leaching residue mainly contains zinc, silver, and calcium sulfate, which can be returned to the rotary kiln for zinc recovery. Sponge lead is obtained by zinc replacement in the chlorination leaching solution. The solution after replacement is neutralized with lime to precipitate zinc and iron. The resulting neutralized residue can be returned to the rotary kiln for zinc recovery, while the neutralized solution is returned to the chlorination leaching system. The sponge lead is then smelted to obtain qualified lead ingots. Alternatively, lead sulfate slag can be slurried and placed in a slurry electrolytic cell for precise control. The resulting multi-element lead-containing material can be directly electrolyzed in the suspension slurry without solidification, directly producing crude lead and purified sulfuric acid. However, the purity of the cathode lead produced is low, containing other impurities, and the current efficiency is reduced. Furthermore, the high power consumption of solid-phase electrolysis leads to excessively high processing costs.

[0008] In the desulfurization-free short-process conversion and regeneration process, waste lead sulfate slag such as lead paste is mixed with a chiral complexing catalyst and leached in a reactor. Then, CO2 is introduced for carbonization transformation, converting lead sulfate into high-purity lead carbonate. The lead carbonate is then decomposed at high temperature using equipment such as a tunnel kiln to obtain lead oxide powder. The CO2 produced from the decomposition is recycled in the carbonization regeneration process. In this process, the chiral complexing catalyst and CO2 are recycled in the first and second processes, respectively. This process is green and environmentally friendly, and can directly produce battery-grade zinc oxide products. This method is widely used in the lead-acid battery recycling industry to achieve the recycling and regeneration of lead sulfate slag. Summary of the Invention

[0009] The purpose of this patent invention is to provide a method for directly reducing lead sulfate slag with basic hydrogen gas to overcome the above-mentioned technical deficiencies. This method is beneficial to significantly reduce the treatment cost of lead sulfate slag, shorten the treatment time, and produce crude lead in one step, thereby reducing the investment and operating costs of lead sulfate slag treatment facilities. Using the method of this patent, lead sulfate slag is directly reduced to crude lead in one step. The crude lead ingots produced can be packaged and sold directly as products, or used directly to manufacture zinc-lead alloy powder. Furthermore, they can be further processed using vacuum distillation to produce lead ingots and zinc ingots to make other high-value-added products. In addition, other reactants such as fluxes and catalysts can be converted into by-products such as sodium sulfate, thereby achieving zero other hazardous waste generation and lower carbon emissions. This process is more environmentally friendly and energy-saving, and the CO2 generated during the process can be recycled, which helps to reduce carbon emissions. It has the characteristics of high efficiency and environmental protection.

[0010] To achieve the above objectives, the technical solution of this patented invention is as follows.

[0011] A method for treating lead sulfate slag using a direct reduction process with basic hydrogen, comprising the following steps: (1) Lead slag containing 20-100% lead sulfate, lead chloride slag and other lead slags are fed into the pretreatment drying system through the feeding system and dried to control the water content to not exceed 5%. Then they are fed into the hydrogen reduction smelting reactor. The raw material of the hydrogen reduction smelting reactor is hydrogen containing 90-99% hydrogen or water gas containing 20-50% CO and 20-50% hydrogen. The hydrogen or water gas comes from the hydrogen or water gas preparation system. Excess sodium carbonate or sodium hydroxide also needs to be added to the hydrogen reduction smelting reactor. The sodium carbonate or sodium hydroxide is fed into the hydrogen reduction smelting reactor through the nitrogen gas conveying feeding system.

[0012] (2) The basic hydrogen reduction reaction conditions in the hydrogen reduction smelting reactor to which step (1) belongs are: while lead sulfate slag and sodium carbonate or caustic soda and their mixture are smelted in an alkaline melting environment in the reactor, water gas mixed with H2 or CO or methane cracking hydrogen is used to directly reduce the valuable components of lead sulfate, lead chloride, etc. to crude lead in one step. (3) The alkaline hydrogen reduction furnace in step (1) includes an electric heating front bed smelting zone. The molten crude lead mixture initially generated in the alkaline hydrogen reduction reactor in step (1) needs to be separated from the slag and valuable metals by natural sedimentation through density difference during heating in the electric heating front bed. The bottom sedimentation zone can directly discharge crude lead containing more than 80% lead, and the side discharge port of the electric heating front bed can discharge sodium sulfate molten salt. The heating and heat preservation temperature of the electric heating front bed smelting zone is 200-600℃, and the smelting time is 10-120min. (4) Step (1) After the sodium sulfate molten salt is discharged through the slag discharge port on the side of the electric heating front bed smelting zone, it is quenched by water to become sodium sulfate solution. Then the sodium sulfate solution enters the sodium sulfate recrystallization system. After the powder crystallization, it is packaged by a ton bag packaging machine to produce Glauber's salt with a sodium sulfate content of more than 90% for sale. (5) The crude lead produced in step (1) is kept in a heat-preserving furnace for 10-120 minutes at a temperature of 300-400 degrees Celsius, and then distilled in a vacuum distillation furnace for 1 hour. After adding coke and caustic soda, it is further processed to obtain products A and B. (6) The product A obtained in step (5) is processed through the ingot casting system to produce lead ingots with a lead content of more than 99% for sale; the economic indicators of lead recovery rate of 80-90% are calculated. (7) The product B obtained in step (5) is high zinc alkali slag. A portion of the high zinc alkali slag enters the rotary kiln or wastewater treatment system to replace caustic soda flakes to adjust the pH value; another portion of the high zinc alkali slag enters the two-stage vacuum distillation furnace for further processing. The product is then processed through the ingot casting system to generate zinc ingots with a zinc content of more than 99% for sale. Finally, the lead + zinc recovery rate of more than 95% is calculated.

[0013] Furthermore, while the lead sulfate slag is alkalinely smelted with sodium carbonate or caustic soda flakes and their mixtures in a molten environment, hydrogen gas prepared by methods such as H2 or CO mixed water gas or methane cracking is used to directly reduce the valuable components of lead sulfate, lead chloride, etc., in lead sulfate to crude lead in one step. This is done under an H2 or CO atmosphere, at a reduction temperature of 100-200℃, an H2 concentration of 50-90%, and an air-to-material ratio of 300-1000 m³ / h. 3With a reducing gas flow rate of 100-600 L / min, a lead sulfate slag grinding fineness of -200 mesh accounting for 70-80%, and an electric heating bed temperature of 400-600℃, the following process indicators can be obtained: crude lead with a lead content of over 80%, lead + zinc content of over 95%, and lead recovery rate of 80-90%; sodium sulfate and mirabilite with a sodium sulfate content of over 90%; lead ingots with a grade of over 99.99%; and zinc ingots with a grade of over 99.9%.

[0014] Furthermore, the core equipment of the direct reduction process and apparatus for lead sulfate slag using basic hydrogen in this patent invention is a hydrogen boiling reduction smelting reactor. This reactor system is equipped with a metering device for adding dry lead sulfate powder to a boiling fluidized bed. Simultaneously, nitrogen gas is used to add sodium hydroxide powder or sodium carbonate powder to the boiling fluidized bed. The boiling fluidized bed is equipped with a hydrogen or water gas vent to ensure that the lead sulfate powder is fully mixed with sodium carbonate or caustic soda powder for effective reduction. The mixture is discharged into the electric heating front bed feeding zone through the boiling layer height of the hydrogen or water gas fluidized bed. In the electric heating front bed, the flue gas and the mixed slag are melted and separated by sedimentation. In the bottom of the electric heating front bed, the reaction temperature is controlled at 400-600℃ by an electromagnetic heater, so that the sponge lead and sodium sulfate are melted and separated. The sodium sulfate can be discharged periodically through the side discharge port for water quenching and recovery. The molten lead metal is discharged through the discharge port of the sedimentation chamber and can be cast into ingots or packaged for subsequent processing.

[0015] Furthermore, in hydrogen or water gas production systems, the produced hydrogen or hydrogen mixed with CO is both flammable and highly reducing. The water gas contains 20-50% CO, 20-50% hydrogen, methane, etc. It primarily provides CO and H2 reducing agents for suspension reduction furnaces. Alternatively, it can be used for room temperature electrochemical steam conversion, direct photovoltaic water electrolysis, or high-purity hydrogen (containing over 99% hydrogen) produced by cracking methane from chemical production.

[0016] Furthermore, the crude lead atomization powder making system heats and atomizes liquid high-lead slag to produce alloy powder, which is then automatically packaged using a ton bag baler. It can be used for other powder metallurgy or displacement and impurity removal agents.

[0017] Furthermore, the vacuum distillation system is a device for purifying liquid high-lead slag through vacuum distillation. It utilizes the differences in boiling points and separation coefficients of zinc, lead, and iron under vacuum conditions for purification.

[0018] Furthermore, the sodium sulfate crystallization automatic packaging system involves water quenching the sodium sulfate slag produced by the hydrogen reduction smelting reactor, followed by secondary recrystallization to produce sodium sulfate mirabilite, which is then packaged into automatic ton bag packaging machines and sold as a by-product.

[0019] Furthermore, the flue gas treatment system includes a gravity settling chamber, a scrubbing tower, an alkaline treatment tower, and an emission chimney.

[0020] Furthermore, the co-solvent and reaction raw materials used in the direct reduction process of lead sulfate slag with basic hydrogen in this patent invention are caustic soda (NaOH) flakes, or soda ash (Na2CO3) and mixtures thereof.

[0021] Furthermore, the reducing agent is high-purity hydrogen, or water gas containing CO and H2, as well as other hydrogen storage alloys containing hydrogen.

[0022] Furthermore, in the method for directly reducing lead sulfate slag with basic hydrogen, the hydrogen reduction reactor for treating lead sulfate slag also requires the addition of sodium carbonate, sodium hydroxide, or a mixture of sodium carbonate and sodium hydroxide. These substances act as alkaline co-solvents and isolate oxygen, catalysts, and decomposition products. Moreover, alkaline substances such as sodium carbonate react synergistically with hydrogen. This process method for treating lead sulfate by synergistic reduction smelting reaction of sodium carbonate or caustic soda with hydrogen and the hydrogen reduction smelting reactor are protected within the scope of this patent.

[0023] This invention relates to a method for treating lead sulfate slag using a direct reduction process with basic hydrogen, comprising the following steps: (1) Lead slag is fed into a pretreatment drying system via a feeding system and then fed into a hydrogen reduction smelting reactor; (2) Valuable components such as lead sulfate and lead chloride in lead sulfate are directly reduced to crude lead in one step; (3) The crude lead is further processed by adding coke and caustic soda to obtain products A and B; (4) Product A is processed into lead ingots with a lead content of over 99% and sold after passing through an ingot casting system; (5) Product B obtained is high-zinc alkali slag. Part of the high-zinc alkali slag is fed into a rotary kiln or wastewater treatment system to replace caustic soda to adjust the pH value; another part of the high-zinc alkali slag is fed into a two-stage vacuum distillation furnace for further processing, and the product is processed into zinc ingots with a zinc content of over 99% and sold after passing through an ingot casting system. This method is more environmentally friendly and energy-saving than other methods or equipment, which helps to recycle and improve utilization efficiency.

[0024] The beneficial effects of this invention are as follows: (1) Since this method uses hydrogen and other strong reducing gases prepared by water gas or natural gas cracking to treat zinc smelting lead sulfate concentrate, lead-acid battery lead sulfate paste and other hazardous waste materials containing lead sulfate and lead chloride, the coal consumption is more than 20% lower than other processes, and its carbon emissions are 20-50% lower than other processes, making it more environmentally friendly and energy-saving than other methods or equipment. (2) Compared with other methods and equipment, the alkaline hydrogen reduction reactor of this invention has a higher system processing capacity for treating lead sulfate slag, which is more conducive to the high-value-added transformation of zinc smelting system lead sulfate concentrate and the rapid and efficient regeneration of lead sulfate paste in the lead-acid battery industry. (3) This method can produce crude lead for sale, can also use the crude lead powdering system to prepare alloy lead powder, and can directly produce high-purity lead ingots and zinc ingots for sale in one step using vacuum distillation equipment. (4) The hydrogen reduction smelting reactor in this invention only requires a reduction temperature of 100~600℃ to process lead sulfate slag, while other methods and equipment require a reaction temperature of 500~1300℃, making it more energy-efficient than other methods and equipment. (5) This patented invention method does not generate any other hazardous waste. The cosolvents such as sodium carbonate and the catalytic conversion agent can be regenerated into sodium sulfate and sodium sulfate as by-products for sale using the recrystallization system. The CO2 released after the reaction of sodium carbonate in the hydrogen reduction smelting reactor can be recycled through the flue gas purification, enrichment and regeneration system. Attached Figure Description

[0025] Figure 1 This is a process flow diagram of the present invention, which includes a vacuum distillation system and produces lead ingots and zinc ingots.

[0026] Figure 2 This is a process flow diagram for producing crude lead as the product in this invention.

[0027] Figure 3 This is a process flow diagram for the alloy lead-zinc powder of this invention.

[0028] Figure 4 This is a schematic diagram of the hydrogen boiling reduction smelting reactor system in this invention. Detailed Implementation

[0029] The specific embodiments of the present invention will now be described in conjunction with the accompanying drawings and examples to provide a better understanding of the invention.

[0030] Example 1 like Figure 1 The method for directly reducing lead sulfate slag with basic hydrogen gas, as shown, has the following specific process steps: Lead slag containing 20-100% lead sulfate, lead chloride slag, and other lead slags are fed into a pretreatment drying system via a feeding system. After drying, the moisture content is controlled to not exceed 5%. Then, they are fed into a hydrogen reduction smelting reactor. The raw material for the hydrogen reduction smelting reactor is hydrogen containing 99% hydrogen or water gas containing 20-50% CO and 20-50% hydrogen. The hydrogen or water gas comes from a hydrogen or water gas preparation system. An excess of sodium carbonate or sodium hydroxide also needs to be added to the hydrogen reduction smelting reactor. The sodium carbonate or sodium hydroxide is added to the hydrogen reduction smelting reactor via a nitrogen gas feeding system.

[0031] The basic hydrogen reduction reaction conditions in the hydrogen reduction smelting reactor to which step (1) belongs are as follows: while lead sulfate slag and sodium carbonate or caustic soda and their mixture are being smelted in an alkaline environment in the reactor, water gas mixed with H2 or CO or methane cracked hydrogen is used to directly reduce the valuable components of lead sulfate, lead chloride, etc. to crude lead in one step. Under the conditions of H2 or CO atmosphere, reduction temperature 100-500℃, H2 concentration 50-90%, air-to-material ratio 300-1000 m3 / t-ore, reducing gas flow rate 100-600 L / min, and lead sulfate slag grinding fineness of -200 mesh accounting for 70-80%, the amount of sodium carbonate or caustic soda added is 10-50% excess based on the stoichiometric ratio of lead to sodium of 2:1 in the basic hydrogen reduction reaction, and the reaction time is 10-60 minutes.

[0032] (3) The alkaline hydrogen-based reduction furnace in step (1) includes an electric heating front-bed smelting zone. The molten crude lead mixture initially generated in the alkaline hydrogen-based reduction reactor in step (1) needs to be separated from the slag and valuable metals by natural sedimentation due to density differences during heating in the electric heating front-bed. The bottom sedimentation zone can directly discharge crude lead containing more than 80% lead, and the side discharge port of the electric heating front-bed can discharge sodium sulfate molten salt. The heating and holding temperature of the electric heating front-bed smelting zone is 200-600℃, and the smelting time is 10-120min.

[0033] (4) Step (1) After the sodium sulfate molten salt is discharged through the slag discharge port on the side of the electric heating front bed smelting zone, it is quenched by water to become sodium sulfate solution. Then the sodium sulfate solution enters the sodium sulfate recrystallization system. After the powder crystallization, it is packaged by a ton bag packaging machine to produce Glauber's salt with a sodium sulfate content of 90% for sale. (5) The crude lead produced in step (1) is kept in a heat-preserving furnace for 10-120 minutes at a temperature of 300-400 degrees Celsius, and then distilled in a vacuum distillation furnace for 1-6 hours. After adding coke and caustic soda, it is further processed to obtain products A and B.

[0034] (6) The product A obtained in step (5) is processed through the casting system to produce lead ingots with a lead content of more than 99% for sale; the economic and technical indicators of lead recovery rate of 80-90% are calculated.

[0035] (7) The product B obtained in step (5) is high-zinc alkali slag. Part of the high-zinc alkali slag enters the rotary kiln or wastewater treatment system to replace caustic soda flakes to adjust the pH value; the other part of the high-zinc alkali slag enters the two-stage vacuum distillation furnace for further processing. The product is then processed through the ingot casting system to generate zinc ingots with a zinc content of more than 99% for sale. Finally, the lead + zinc recovery rate of more than 95% is achieved.

[0036] The principle equation for the method of treating lead sulfate slag using the direct reduction process with basic hydrogen in this embodiment is as follows: Reaction principle equation 1: PbSO4 + 2H2(g) = Pb + 2H2O + SO2(g) (reaction only occurs above 500 degrees Celsius) Reaction principle equation 2: PbSO4 + Na2CO3 + H2(g) = Pb + H2O + Na2SO4 + CO2(g) (reacts very easily above 0 degrees Celsius) Reaction principle equation 3: PbSO4 + H2(g) + 2NaOH = Pb + 2H2O + Na2SO4 (reacts very easily above 0 degrees Celsius) Reaction principle equation 4: ZnSO4 + Na2CO3 + H2(g) = Zn + H2O + Na2SO4 + CO2(g) (Reaction begins above 200 degrees Celsius) Reaction principle equation 5: Fe2(SO4)3 + 3Na2CO3 + 3H2(g) = 2Fe + 3H2O + 3Na2SO4 + 3CO2(g) (reacts very easily above 0 degrees Celsius) Reaction principle equation 6: PbCl2 + Na2CO3 + H2(g) = Pb + H2O + 2NaCl + CO2(g) (Reaction is very easy above 0 degrees Celsius) Reaction principle equation 7: PbSO4 + Na2CO3 + CO(g) = Pb + Na2SO4 + 2CO2(g) (reacts very easily above 0 degrees Celsius) Reference Figure 1 The direct reduction process of basic hydrogen for lead sulfate slag in this embodiment can be used to treat zinc-containing lead sulfate concentrate produced during lead-zinc smelting, or other lead sulfate, lead chloride, or lead sulfate paste produced in industries such as lead-acid batteries. The main component is lead sulfate. Alternatively, it can be lead chloride or other lead slag hazardous waste. The lead sulfate content can be 20-100%, and the water content can not exceed 5%. Example 2

[0037] like Figure 2 As shown, the direct reduction process of lead sulfate slag with basic hydrogen in this embodiment includes the following steps: (1) Lead slag containing 20-100% lead sulfate, lead chloride slag and other lead slags are fed into the pretreatment drying system through the feeding system and dried to control the water content to not exceed 5%. Then they are fed into the hydrogen reduction smelting reactor. The raw material of the hydrogen reduction smelting reactor is hydrogen containing 99% hydrogen or water gas containing 20-50% CO and 20-50% hydrogen. The hydrogen or water gas comes from the hydrogen or water gas preparation system. Excess sodium carbonate or sodium hydroxide also needs to be added to the hydrogen reduction smelting reactor. The sodium carbonate or sodium hydroxide is fed into the hydrogen reduction smelting reactor through the nitrogen gas conveying feeding system.

[0038] (2) The basic hydrogen reduction reaction conditions in the hydrogen reduction smelting reactor to which step (1) belongs are as follows: while lead sulfate slag and sodium carbonate or caustic soda and their mixture are alkalinely smelted in the molten environment in the reactor, water gas or methane cracking hydrogen mixed with H2 or CO is used to directly reduce the valuable components of lead sulfate, lead chloride, etc. to crude lead in one step. Under the conditions of H2 or CO atmosphere, reduction temperature 100-500℃, H2 concentration 50-90%, air-to-material ratio 300-1000 m3 / t-ore, reducing gas flow rate 100-600 L / min, and lead sulfate slag grinding fineness of -200 mesh accounting for 70-80%, the amount of sodium carbonate or caustic soda added is 10-50% excess based on the stoichiometric ratio of lead to sodium in the basic hydrogen reduction reaction of 2:1, and the reaction time is 10-60 minutes.

[0039] (3) The alkaline hydrogen-based reduction furnace in step (1) includes an electric heating front-bed smelting zone. The molten crude lead mixture initially generated in the alkaline hydrogen-based reduction reactor in step (1) needs to be separated from the slag and valuable metals by natural sedimentation due to density differences during heating in the electric heating front-bed. The bottom sedimentation zone can directly discharge crude lead containing more than 80% lead, and the side discharge port of the electric heating front-bed can discharge sodium sulfate molten salt. The heating and holding temperature of the electric heating front-bed smelting zone is 200-600℃, and the smelting time is 10-120min.

[0040] (4) Step (1) After the sodium sulfate molten salt is discharged through the slag discharge port on the side of the electric heating front bed smelting zone, it is quenched by water to become sodium sulfate solution. Then the sodium sulfate solution enters the sodium sulfate recrystallization system. After crystallization into powder, it is packaged by a ton bag packaging machine to produce Glauber's salt product with a sodium sulfate content of more than 90% for sale. (5) After the crude lead product produced in step (1) enters the crude lead ingot casting system, crude lead ingots containing more than 80% lead and 5-50% zinc are generated and sold directly.

[0041] The principle equation for the method of treating lead sulfate slag using the direct reduction process with basic hydrogen in this embodiment is as follows: Reaction principle equation 1: PbSO4 + 2H2(g) = Pb + 2H2O + SO2(g) (reaction only occurs above 500 degrees Celsius) Reaction principle equation 2: PbSO4 + Na2CO3 + H2(g) = Pb + H2O + Na2SO4 + CO2(g) (reacts very easily above 0 degrees Celsius) Reaction principle equation 3: PbSO4 + H2(g) + 2NaOH = Pb + 2H2O + Na2SO4 (reacts very easily above 0 degrees Celsius) Reaction principle equation 4: ZnSO4 + Na2CO3 + H2(g) = Zn + H2O + Na2SO4 + CO2(g) (Reaction begins above 200 degrees Celsius) Reaction principle equation 5: Fe2(SO4)3 + 3Na2CO3 + 3H2(g) = 2Fe + 3H2O + 3Na2SO4 + 3CO2(g) (reacts very easily above 0 degrees Celsius) Reaction principle equation 6: PbCl2 + Na2CO3 + H2(g) = Pb + H2O + 2NaCl + CO2(g) (Reaction is very easy above 0 degrees Celsius) Reaction principle equation 7: PbSO4 + Na2CO3 + CO(g) = Pb + Na2SO4 + 2CO2(g) (reacts very easily above 0 degrees Celsius) The molten liquid high-lead slag can be fed into the crude lead casting system directly to produce crude lead for sale. Alternatively, the molten liquid high-lead slag can be placed into a holding furnace and then sprayed through an atomizing tank to produce lead-zinc alloy powder. Or, the molten liquid high-lead slag can be placed into a vacuum distillation furnace for distillation and purification to produce high-purity lead and zinc ingots for sale.

[0042] Considering that impurities such as ferric sulfate in the lead sulfate slag will also enter the liquid high-lead slag during the reaction, resulting in the liquid high-lead slag containing extremely high levels of impurities such as zinc and iron, it needs to be put back into the vacuum distillation furnace system for further purification, and high-purity lead ingots and high-purity zinc ingots will be produced through vacuum distillation. Example 3

[0043] like Figure 3 As shown, the process steps in this embodiment are as follows: (1) Lead slag containing 20-100% lead sulfate, lead chloride slag and other lead slags are fed into the pretreatment drying system through the feeding system and dried to control the water content to not exceed 5%. Then they are fed into the hydrogen reduction smelting reactor. The raw material of the hydrogen reduction smelting reactor is hydrogen containing 99% hydrogen or water gas containing 20-50% CO and 20-50% hydrogen. The hydrogen or water gas comes from the hydrogen or water gas preparation system. Excess sodium carbonate or sodium hydroxide also needs to be added to the hydrogen reduction smelting reactor. The sodium carbonate or sodium hydroxide is fed into the hydrogen reduction smelting reactor through the nitrogen gas conveying feeding system.

[0044] (2) The basic hydrogen reduction reaction conditions in the hydrogen reduction smelting reactor to which step (1) belongs are as follows: while lead sulfate slag and sodium carbonate or caustic soda and their mixture are alkalinely smelted in the molten environment in the reactor, water gas or methane cracking hydrogen mixed with H2 or CO is used to directly reduce the valuable components of lead sulfate, lead chloride to crude lead in one step. Under the conditions of H2 or CO atmosphere, reduction temperature 100-500℃, H2 concentration 50-90%, air-to-material ratio 300-1000 m3 / t-ore, reducing gas flow rate 100-600 L / min, and lead sulfate slag grinding fineness of -200 mesh accounting for 70-80%, the amount of sodium carbonate or caustic soda added is 10-50% excess based on the stoichiometric ratio of lead to sodium in the basic hydrogen reduction reaction of 2:1, and the reaction time is 10-60 minutes.

[0045] (3) The alkaline hydrogen-based reduction furnace in step (1) includes an electric heating front-bed smelting zone. The molten crude lead mixture initially generated in the alkaline hydrogen-based reduction reactor in step (1) needs to be separated from the slag and valuable metals by natural sedimentation due to density differences during heating in the electric heating front-bed. The bottom sedimentation zone can directly discharge crude lead containing more than 80% lead, and the side discharge port of the electric heating front-bed can discharge molten sodium sulfate. The heating and holding temperature of the electric heating front-bed smelting zone is 200-600℃, and the smelting time is 10-120min.

[0046] (4) Step (1) After the sodium sulfate molten salt is discharged through the slag discharge port on the side of the electric heating front bed smelting zone, it is quenched by water to become sodium sulfate solution. Then the sodium sulfate solution enters the sodium sulfate recrystallization system. After crystallization into powder, it is packaged by a ton bag packaging machine to produce Glauber's salt product with a sodium sulfate content of more than 90% for sale. (5) The crude lead product produced in step (1) is kept in a heat preservation furnace at a temperature of 300-400 degrees Celsius for 10-60 minutes. Then, it is atomized in an atomizing tank through vacuum suction to generate alloy lead powder containing 5-50% zinc and 80-95% lead, which is then sold directly.

[0047] The principle equation for the method of treating lead sulfate slag using the direct reduction process with basic hydrogen in this embodiment is as follows: Reaction principle equation 1: PbSO4 + 2H2(g) = Pb + 2H2O + SO2(g) (reaction only occurs above 500 degrees Celsius) Reaction principle equation 2: PbSO4 + Na2CO3 + H2(g) = Pb + H2O + Na2SO4 + CO2(g) (reacts very easily above 0 degrees Celsius) Reaction principle equation 3: PbSO4 + H2(g) + 2NaOH = Pb + 2H2O + Na2SO4 (reacts very easily above 0 degrees Celsius) Reaction principle equation 4: ZnSO4 + Na2CO3 + H2(g) = Zn + H2O + Na2SO4 + CO2(g) (Reaction begins above 200 degrees Celsius) Reaction principle equation 5: Fe2(SO4)3 + 3Na2CO3 + 3H2(g) = 2Fe + 3H2O + 3Na2SO4 + 3CO2(g) (reacts very easily above 0 degrees Celsius) Reaction principle equation 6: PbCl2 + Na2CO3 + H2(g) = Pb + H2O + 2NaCl + CO2(g) (Reaction is very easy above 0 degrees Celsius) Reaction principle equation 7: PbSO4 + Na2CO3 + CO(g) = Pb + Na2SO4 + 2CO2(g) (reacts very easily above 0 degrees Celsius) Example 4

[0048] The apparatus used in this invention, such as Figure 4 As shown, the working process and principle of the above-mentioned hydrogen reactor are as follows: (1) The dried lead sulfate slag and other raw materials enter the reaction zone 13 through the feeding port and feeding pipe 1. The reaction zone 13 is lined with refractory and anti-corrosion castable. The side of the reaction zone 13 is provided with auxiliary material feeding port 2. Sodium hydroxide or sodium carbonate powder, which is pneumatically transported by nitrogen, can be fed into the reactor through the feeding port 2. The reaction zone 13 is lined with refractory and anti-corrosion castable. After being treated by the hydrogen boiling fluidized bed 3 with electric heating, the product enters the electric heating front bed smelting zone 5 with electromagnetic heating and refractory castable through the boiling discharge port 11. After the treatment is completed, the product enters the molten lead slag settling zone 8 and is discharged through the lead discharge port at the bottom corresponding to the automatic casting or collection device 9.

[0049] On the other side of the smelting zone, at the upper part, there is a boiling discharge port 11 for collecting the flue gas and boiling discharge reaction mixture in the reaction zone 13. Another part of the flue gas is discharged through a steam or CO2 flue gas collection and discharge port 12 or enriched, purified, and recycled. The discharged flue gas, carrying the mixture, enters the electric heating forebed smelting zone 5 through the gravity sedimentation separation zone of flue gas and lead metal and sodium sulfate and the electric heating forebed feed port 14. The linings of the reaction zone 13 and the feed port 14 are both refractory and corrosion-resistant castables. The side wall of the reaction zone 13 is provided with a hydrogen or water gas inlet 4 to facilitate the introduction of reducing gases such as hydrogen or water gas.

[0050] After entering the slag flushing and water quenching zone, which has a sodium sulfate discharge port 10 on the side wall of the smelting zone 5, the sodium sulfate recrystallization and packaging system can be connected. The entire device is supported by a first fixed base 6 and a second fixed base 7 at the bottom.

[0051] The above description is a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and variations can be made without departing from the principle of the present invention, and these improvements and variations are also considered to be within the scope of protection of the present invention.

Claims

1. A method of processing lead sulfate residue by a base hydrogen direct reduction process, characterized in that: The process steps are as follows: (1) The lead sulfate slag containing 20-100% lead sulfate, lead chloride slag and other lead slag is fed into the pretreatment drying system through the feeding system after drying to control the water content to be not more than 5%, and then is fed into the hydrogen reduction smelting reaction furnace. The raw material of the hydrogen reduction smelting reaction furnace is hydrogen containing 90-99% hydrogen or water gas containing 20-50% CO and 20-50% hydrogen, and the hydrogen or water gas is obtained from a hydrogen or water gas preparation system. Excess sodium carbonate or sodium hydroxide is also added to the hydrogen reduction smelting reaction furnace, and the sodium carbonate or sodium hydroxide is fed into the hydrogen reduction smelting reaction furnace through a nitrogen gas feeding system; (2) The alkali hydrogen reduction reaction conditions in the hydrogen reduction smelting reaction furnace of step (1) are as follows: while the lead sulfate slag, sodium carbonate or caustic soda and their mixture are smelted in an alkaline molten environment in the reaction furnace, H2 or CO mixed water gas or methane cracking hydrogen is used to directly reduce the valuable components of lead sulfate and lead chloride in the lead sulfate to crude lead in one step; (3) The alkali hydrogen reduction furnace of step (1) includes an electrically heated front bed smelting zone. The molten crude lead mixture preliminarily generated in the alkali hydrogen reduction furnace of step (1) needs to be separated by natural sedimentation of slag and valuable metals in the electrically heated front bed heating zone. The bottom sedimentation zone can directly discharge crude lead containing more than 80% lead, and the side discharge port of the electrically heated front bed can discharge sodium sulfate molten salt. The heating and insulation temperature of the electrically heated front bed smelting zone is 200-600°C, and the smelting time is 10-120 min; (4) After the sodium sulfate molten salt is discharged from the side discharge port of the electrically heated front bed smelting zone of step (1), it is quenched with water to become a sodium sulfate solution, and then the sodium sulfate solution enters a sodium sulfate recrystallization system. After powder crystallization, it is packaged by a ton bag packer to produce Glauber's salt containing more than 90% sodium sulfate for sale; (5) The crude lead produced in step (1) is heated in a heat preservation furnace for 10-120 min at a temperature of 300-400°C, and then is subjected to distillation in a vacuum distillation furnace for 1 h. After the addition of coke and caustic soda, products A and B are obtained; (6) Product A obtained in step (5) is subjected to an ingot casting system to produce lead ingots containing more than 99% lead for sale. The process economic indicators of lead recovery rate of 80-90% are calculated; (7) Product B obtained in step (5) is high-zinc alkali slag. Part of the high-zinc alkali slag is fed into a rotary kiln or a wastewater treatment system to replace caustic soda to adjust the pH value. Another part of the high-zinc alkali slag is fed into a two-stage vacuum distillation furnace for further treatment to obtain products, which are subjected to an ingot casting system to produce zinc ingots containing more than 99% zinc for sale, and finally the lead+zinc recovery rate of more than 95% is realized.

2. The method of processing lead sulfate slag by base hydrogen direct reduction process according to claim 1, characterized in that: The lead sulfate slag is directly reduced to crude lead by H2 or CO mixed water gas or methane cracking hydrogen in a molten environment while alkali smelting with sodium carbonate or caustic soda and mixtures thereof, the valuable components of lead sulfate and lead chloride in the lead sulfate are directly reduced to crude lead, under the conditions of H2 or CO atmosphere, reduction temperature 100-200℃, H2 concentration 50-90%, wind material ratio 300-1000 m 3 / t-ore, reduction gas flow 100-600 L / min, lead sulfate slag grinding fineness-200 mesh accounting for 70-80%, electric heating front bed heating temperature 400-600℃, process indicators of crude lead containing more than 80% lead, lead+zinc more than 95%, lead recovery rate 80-90% can be obtained, sodium sulfate mirabilite containing more than 90% sodium sulfate, lead ingot more than 99.99% grade, zinc ingot more than 99.9% grade.

3. The method of processing lead sulfate slag by base hydrogen direct reduction process as claimed in claim 1, wherein: The hydrogen gas reduction smelting reaction furnace is provided with a metering device, a dry lead sulfate powder feeding port and a feeding pipeline for adding lead sulfate powder into the boiling fluidized bed, and nitrogen gas is used to add sodium hydroxide powder or sodium carbonate powder into the boiling fluidized bed, the boiling fluidized bed is provided with a hydrogen or water gas nozzle to fully mix the lead sulfate powder with sodium carbonate or caustic soda powder for effective reduction reaction, the mixture is discharged into the electrically heated front bed feeding area through the boiling layer height of the hydrogen or water gas fluidized bed, the flue gas and the mixed slag are separated by melting and settling in the electrically heated front bed, the reaction temperature is controlled at 400-600°C by the electromagnetic heater in the bottom of the electrically heated front bed, so that the sponge lead is separated from the sodium sulfate, the sodium sulfate can be regularly discharged through the side discharge port for water quenching and recovery, and the molten lead metal is discharged through the discharge port of the settling bin for ingot casting or packaging into the subsequent process.

4. The method of processing lead sulfate slag by base hydrogen direct reduction process as claimed in claim 1 wherein: In the hydrogen gas or water gas preparation system, the produced hydrogen gas or hydrogen gas mixed with CO is combustible and has strong reducing property; the water gas contains 20-50% CO, 20-50% hydrogen, methane and the like; the hydrogen gas is mainly used for providing CO and H2 reducing agents for the hydrogen gas boiling reduction smelting reaction furnace, or is produced by room temperature electrochemical water electrolysis, photovoltaic direct water electrolysis, or is high-purity hydrogen gas produced by cracking methane, containing more than 99% hydrogen.

5. The method of processing lead sulfate slag by base hydrogen direct reduction process as claimed in claim 1 wherein: The crude lead atomization powder system is used for heat preservation and atomization of liquid high-lead slag to produce alloy powder, and then uses a ton bag packer for automatic packaging, which can be used for other powder metallurgy or replacement of impurity removal agents.

6. The method of processing lead sulfate slag by base hydrogen direct reduction process as claimed in claim 1 wherein: The vacuum distillation system is used for vacuum distillation of liquid high-lead slag, and is used for purification by using the different boiling points and separation coefficients of zinc, lead and iron under vacuum conditions.

7. The method of processing lead sulfate slag by base hydrogen direct reduction process as claimed in claim 1 wherein: The automatic packaging system of sodium sulfate crystals is used for water quenching of sodium sulfate slag produced by the hydrogen gas reaction furnace, secondary recrystallization of sodium sulfate mirabilite, and then packaging as by-products for sale using an automatic ton bag packer.

8. The method of processing lead sulfate slag by base hydrogen direct reduction process as claimed in claim 1 wherein: The flue gas treatment system includes a gravity settling bin, a washing tower, an alkali liquid harm removal tower and a discharge chimney.

9. The method of processing lead sulfate slag by base hydrogen direct reduction process as claimed in claim 1 wherein: The solubilizing agent and reaction raw material used in the lead sulfate slag alkali-based hydrogen direct reduction process are caustic soda NaOH or soda ash Na2CO3 and their mixtures.

10. The method of processing lead sulfate slag by base hydrogen direct reduction process as claimed in claim 1 wherein: The reducing material is high-purity hydrogen gas, water gas containing CO and H2, and other hydrogen storage alloys containing hydrogen gas.

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