Method for preparing iron oxide and high-purity phosphorus pentoxide by utilizing phosphorus-containing and iron-containing wastes
Through the fire process and spray feed technology, the phosphorus and iron recovery process in the phosphorus and iron slag is simplified, the problems of cumbersome steps and insufficient purity are solved, and the preparation of high-purity phosphorus pentoxide is realized to meet the high purity needs in the battery field.
Patent Information
- Application Number
- CN202510482327.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-17
- Publication Date
- 2025-05-27
AI Technical Summary
In the prior art, the process steps for recovering phosphorus and iron in phosphorus and iron slag are cumbersome, resulting in a large amount of heavy metals or acidic wastewater, and the purity of the product is difficult to meet the high purity needs in the battery field.
The ignition process is adopted to heat and melt the phosphorus-containing iron waste in an inert environment, and spray it into the reactor through spraying to react with oxygen to produce high-purity phosphorus pentoxide and iron oxides, and high-purity phosphorus pentoxide is obtained through secondary sublimation.
The process flow is simplified, the wastewater production volume is significantly reduced, the wastewater treatment cost is reduced, and the recovery rate and purity of phosphorus pentoxide is improved to 99.9%, meeting the high purity needs in the battery field.
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Figure CN120039950A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of solid waste utilization, and in particular to a method for preparing iron oxide and high-purity phosphorus pentoxide by utilizing phosphorus- and iron-containing wastes. Background Art
[0002] Lithium iron phosphate batteries are rapidly growing in applications in new energy vehicles and other fields due to their excellent safety performance, long cycle life, and low cost. In order to meet the high performance of the battery, the purity of the raw materials used to prepare lithium iron phosphate is required to be high, usually reaching more than 99%.
[0003] Ferrophosphorus slag is a by-product of yellow phosphorus production. The raw material source is wide and the price is cheap. For every ton of yellow phosphorus produced, the by-product ferrophosphorus slag is 100-200 kg. With the development of the phosphorus production industry, a large amount of ferrophosphorus slag is produced and needs to be treated. The phosphorus content in ferrophosphorus slag is 18-28%, the iron content is 64-72%, and the rest contains a small amount of silicon, manganese, calcium, aluminum, magnesium, vanadium, etc. At present, ferrophosphorus slag is mostly used as waste slag or randomly piled up. The value of ferrophosphorus slag has not been fully utilized, resulting in serious waste of resources and environmental pollution. At the same time, with the increasing depletion of phosphate resources, it has become a top priority to improve the high-value utilization of ferrophosphorus slag.
[0004] In order to improve the effective utilization rate of ferrophosphorus slag, comprehensive recovery of phosphorus and iron elements in ferrophosphorus slag and use for the production of high value-added products has become a research hotspot that has attracted much attention. In the related technology, the following process is used to recover phosphorus and iron in ferrophosphorus slag: the ferrophosphorus slag is mixed with sodium hydroxide, and ferric oxide is obtained after roasting, water immersion, solid-liquid separation, filter cake washing, and drying; the filtrate is concentrated, crystallized, and dried to obtain sodium phosphate. This process of recovering phosphorus and iron in ferrophosphorus slag requires roasting, water immersion, solid-liquid separation, washing, drying, concentration, crystallization and other processes. Not only are the steps cumbersome, but also a large amount of heavy metals or acidic wastewater will be generated, and the treatment cost is high; in addition, this process of recovering phosphorus and iron in ferrophosphorus slag, the purity of phosphate and iron oxide is difficult to meet the high purity requirements in the battery field.
[0005] Therefore, improving the process of recovering phosphorus and iron in ferrophosphorus slag to improve its quality has become a technical problem that needs to be solved urgently by those skilled in the art. Summary of the invention
[0006] The invention discloses a method for preparing iron oxide and high-purity phosphorus pentoxide by utilizing phosphorus- and iron-containing wastes, so as to solve the technical problems in the related art of recovering phosphorus and iron from ferrophosphorus slag, such as complicated steps, generation of a large amount of heavy metals or acidic wastewater, and difficulty in satisfying the requirements of the battery field in terms of product purity.
[0007] In order to solve the above problems, the present invention adopts the following technical solutions: The method for preparing iron oxide and high-purity phosphorus pentoxide by using phosphorus- and iron-containing wastes of the present invention comprises the following steps: After crushing the solid phosphorus-containing and iron-containing waste, heat and melt it in an inert environment, and spray the melted phosphorus-containing and iron-containing waste into the first reaction furnace by blowing, or spray the liquid phosphorus-containing and iron-containing waste into the first reaction furnace by blowing; at the same time, oxygen-containing gas is introduced into the first reaction furnace; The first reaction furnace is heated to 360-900°C and kept warm for 30-60 minutes, and phosphorus-containing and iron-containing waste reacts with oxygen to obtain P 2 O 5 crude steam and iron oxides; Collect P from the top of the first reactor 2 O 5 Steam crude product, iron oxides are collected from the bottom of the first reaction furnace; The collected P 2 O 5 The crude steam product is passed into the second reaction furnace, and the second reaction furnace is heated to above 360°C and kept warm for 30-60 minutes to obtain high-purity P 2 O 5 steam.
[0008] According to an optional embodiment, the temperature of the first reaction furnace is raised to 400-700°C.
[0009] According to an optional embodiment, the first reaction furnace is divided into a first reaction zone and a second reaction zone, the first reaction zone is located above the second reaction zone, and the temperature of the second reaction zone is controlled to be higher than the temperature of the first reaction zone.
[0010] According to an optional embodiment, the temperature of the second reaction zone is controlled to be 50-100° C. higher than the temperature of the first reaction zone.
[0011] According to an optional embodiment, when the molten phosphorus- and iron-containing waste is sprayed into the first reaction furnace by spraying with an atomizing nozzle, the material is sprayed downward from the top of the first reaction furnace, and the oxygen-containing gas is introduced upward from the bottom of the first reaction furnace.
[0012] According to an optional embodiment, the atomizing nozzle is fixed on the wall surface of the first reaction furnace, and the spraying direction of the atomizing nozzle forms an angle of 30° to 60° with the inner wall of the first reaction furnace.
[0013] According to an optional embodiment, the phosphorus- and iron-containing waste is one or more of ferrophosphorus slag, high-phosphorus molten iron, yellow ferrophosphorus slag, and ferrophosphorus ore.
[0014] According to an optional embodiment, the solid phosphorus- and iron-containing waste is crushed to 200-500 mesh and then heated and melted in an inert environment.
[0015] According to an optional embodiment, the heating method is one or more of induction heating, microwave heating, fuel combustion heating, arc heating, plasma heating, and roasting heating, and the heating temperature is 400~600℃.
[0016] According to an optional embodiment, when oxygen-containing gas is introduced into the first reaction furnace, when the oxygen concentration is lower than 21%, the obtained iron oxide is trimer tetroxide; when the oxygen concentration is equal to or higher than 21%, the obtained iron oxide is ferric oxide.
[0017] The technical solution adopted by the present invention can achieve the following beneficial effects: The method for preparing iron oxide and high-purity phosphorus pentoxide from phosphorus-containing and iron-containing wastes of the present invention only requires the steps of melting, blowing, oxidation and secondary sublimation. Compared with the related art that adopts a wet process to recover iron and phosphorus from phosphorus-containing and iron-containing wastes, the method for preparing iron oxide and high-purity phosphorus pentoxide from phosphorus-containing and iron-containing wastes of the present invention adopts a pyrometallurgical process, has the advantages of a simple process flow, and can greatly reduce the amount of wastewater generated, thereby reducing or even omitting the cost of wastewater treatment; on the other hand, the method of blowing feed can make the phosphorus in the phosphorus-containing and iron-containing wastes fully contact with oxygen and generate phosphorus pentoxide, which is beneficial to improving the recovery rate of phosphorus pentoxide; at the same time, the phosphorus pentoxide generated by the combination of phosphorus and oxygen overflows in the form of steam, and the purity of the obtained phosphorus pentoxide is as high as 99.9%, which can meet the demand for raw material purity in the battery field.
[0018] That is, the present invention uses phosphorus- and iron-containing waste to prepare iron oxides and high-purity phosphorus pentoxide. The above scheme is adopted to solve the technical problems of the process of recovering phosphorus and iron from ferrophosphorus slag in the related technology, which has complicated steps, produces a large amount of heavy metals or acidic wastewater, and the product purity is difficult to meet the needs of the battery field. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] In order to more clearly illustrate the embodiments of the present invention or the 99. technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0020] Figure 1 The present invention discloses a flow chart of a method for preparing iron oxide and high-purity phosphorus pentoxide by utilizing phosphorus- and iron-containing wastes.
[0021] Figure 2This is a diagram of the equipment for preparing iron oxide and high-purity phosphorus pentoxide using phosphorus- and iron-containing wastes in an embodiment of the present application.
[0022] Figure 3 It is a schematic diagram of the injection direction and the oxygen-containing gas intake direction of the embodiment of the present application.
[0023] In the figure: 100, first reaction furnace; 110, first reaction zone; 120, second reaction zone; 200, induction furnace; 300, spray gun; 400, induced draft fan; 500, absorption device. DETAILED DESCRIPTION
[0024] To make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.
[0025] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here, and the objects distinguished by "first", "second", etc. are generally of one type, and the number of objects is not limited. For example, the first object can be one or more. In addition, "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.
[0026] In the related art, a wet process is used to recover phosphorus and iron from ferrophosphorus slag, which has complicated steps and produces a large amount of heavy metals or acidic wastewater, resulting in high wastewater treatment costs. In addition, in this process of recovering phosphorus and iron from ferrophosphorus slag, the recovery rate and purity of iron and phosphorus are greatly affected by impurities, and the resulting product is difficult to meet the high-purity requirements in the battery field. The present application uses a pyrometallurgical process to recover phosphorus and iron from ferrophosphorus slag, which can avoid the above problems. Furthermore, the present invention adopts a blowing feed method, which is beneficial to improve the recovery rate of phosphorus pentoxide; at the same time, phosphorus pentoxide generated by the combination of phosphorus and oxygen overflows in the form of steam, and the resulting phosphorus pentoxide has a purity of up to 99.9%, which can meet the demand for raw material purity in the battery field.
[0027] The following is combined with Figures 1 to 3 The method for preparing iron oxide and high-purity phosphorus pentoxide using phosphorus-containing and iron-containing waste provided in the present application is described in detail through specific embodiments and application scenarios.
[0028] Figure 1 The flowchart of the method for preparing iron oxide and high-purity phosphorus pentoxide using phosphorus-containing and iron-containing wastes is shown in the present application. Figure 1 As shown, the method of preparing iron oxide and high-purity phosphorus pentoxide using phosphorus-containing and iron-containing wastes in the present application comprises the following steps: Step 100: After crushing the solid phosphorus- and iron-containing waste, heat and melt it in an inert environment, and spray the molten phosphorus- and iron-containing waste into the first reaction furnace by blowing, or spray the liquid phosphorus- and iron-containing waste into the first reaction furnace by blowing; at the same time, oxygen-containing gas is introduced into the first reaction furnace.
[0029] In some embodiments, the phosphorus-containing and iron-containing waste is phosphorus-containing and iron-containing waste slag or phosphorus-containing and iron-containing waste water generated in the industrial production process. Exemplarily, the phosphorus-containing and iron-containing waste is one or more of phosphorus-iron slag, high-phosphorus molten iron, yellow phosphorus-iron slag, and phosphorus-iron ore. Exemplarily, the phosphorus element in the phosphorus-containing and iron-containing waste is 10-30%, and the iron element is 30-70%.
[0030] Liquid phosphorus- and iron-containing wastes can be directly sprayed into the first reaction furnace for reaction.
[0031] For solid phosphorus-containing and iron-containing waste, after crushing, it is heated and melted in an inert environment, and then sprayed into the first reaction furnace for reaction by blowing. Preferably, the solid phosphorus-containing and iron-containing waste is crushed to 200-500 mesh. The heating method is one or more of induction heating, microwave heating, fuel combustion heating, arc heating, plasma heating, and roasting heating. Exemplarily, the inert environment is a nitrogen atmosphere, and heating and melting the solid phosphorus-containing and iron-containing waste in an inert environment will not cause the loss of phosphorus in the phosphorus-containing and iron-containing waste. Exemplarily, the crushed phosphorus-containing and iron-containing waste is heated to 1000-1400°C and is in a molten state.
[0032] Preferably, the liquid phosphorus-containing iron-containing waste or the molten phosphorus-containing iron-containing waste is sprayed into the first reaction furnace in the form of atomized droplets or atomized particles using an atomizing nozzle for reaction. Exemplarily, the spraying pressure is 0.6-0.7 MPa, and the nozzle aperture is 100-300 mesh. Exemplarily, the particle size of the atomized droplets or atomized particles is 25-100 microns.
[0033] After solid phosphorus- and iron-containing waste is heated and melted, the mineral lattice is destroyed, and the phosphorus originally dissolved in the oxide lattice or wrapped in silicate is released as free phosphorus, which is conducive to the subsequent contact between phosphorus and oxygen and the production of phosphorus pentoxide. Furthermore, crushing the phosphorus- and iron-containing waste before heating and melting can reduce energy consumption and shorten the melting time.
[0034] However, the inventors found in their research that heating and melting are difficult to completely release the encapsulated phosphorus. Generally, melting can reduce the encapsulation rate of phosphorus from 30% to 50% to about 5% (part of the phosphorus is encapsulated in unmelted particles with a higher melting temperature). Since part of the encapsulated phosphorus is always difficult to release, the yield of phosphorus pentoxide has a bottleneck. The present application adopts a blowing method to spray phosphorus-containing and iron-containing waste into the first reactor. On the one hand, the blowing can disperse the molten body into fine droplets or particles, increase the specific surface area, make the encapsulated phosphorus more easily exposed to the surface, and improve the reaction rate and the yield of phosphorus pentoxide; on the other hand, the shear force caused by high-speed blowing can destroy the mineral phase boundary inside the slag body, which is conducive to the release of the encapsulated phosphorus, thereby further improving the reaction rate and the yield of phosphorus pentoxide. Furthermore, the present application adopts a blowing method to spray phosphorus-containing and iron-containing waste into the first reactor. The fluidity of the blowing can also prevent the problem that phosphorus is secondary encapsulated in iron oxide to form a eutectic when the molten body is in a static state, thereby ensuring the yield of phosphorus pentoxide.
[0035] In some embodiments, when the oxygen-containing gas is introduced into the first reaction furnace, the oxygen-containing gas is introduced into the first reaction furnace, and the oxygen concentration in the first reaction furnace is maintained at 15-50%. Specifically, when it is an oxygen-rich gas, the iron oxide obtained is ferric oxide; when it is a weak oxygen gas, the iron oxide obtained is ferroferric oxide. Exemplarily, when the oxygen concentration is lower than 21%, the iron oxide obtained is ferroferric oxide; when the oxygen concentration is equal to or higher than 21%, the iron oxide obtained is ferric oxide.
[0036] Ferric oxide has high stability, while ferroferric oxide is magnetic and easily leached by dilute acid. Due to their different properties, their application ranges are also different. The method of preparing iron oxide and high-purity phosphorus pentoxide using phosphorus-containing and iron-containing wastes in this application can selectively obtain ferric oxide or ferroferric oxide based on actual needs by controlling the oxygen content of the introduced gas, which can meet different application needs.
[0037] Step 200: The first reaction furnace is heated to 360-900°C and kept warm for 30-60 minutes, and phosphorus-containing and iron-containing waste reacts with oxygen to obtain P 2 O 5 Steam crude and iron oxides.
[0038] Preferably, the first reaction furnace is heated to 400-700°C.
[0039] The present application adopts a blowing method to spray phosphorus-containing and iron-containing waste into a first reaction furnace, and at the same time, oxygen-containing gas is introduced into the first reaction furnace, phosphorus is combined with oxygen to generate phosphorus pentoxide, and the phosphorus pentoxide overflows in the form of steam at a temperature of 360-900°C, while the remaining impurities are precipitated in a solid state at the bottom of the reaction furnace. The phosphorus pentoxide obtained in this way has a higher purity.
[0040] Step 300: Collect P from the top of the first reactor 2 O 5 Steam crude product, iron oxides are collected from the bottom of the first reaction furnace. For example, a cyclone separation and dust removal device can be installed on the top of the first reaction furnace, and the P in the first reaction furnace 2 O 5 P obtained after steam is dusted by cyclone separation and dust removal device 2 O 5 Steam purity is further improved.
[0041] The present invention introduces oxygen-containing gas into the first reaction furnace, causing part of the dust in the first reaction furnace to be blown up and carried along with P 2 O 5 Steam crude product overflows, and a cyclone separation and dust removal device is installed on the top of the first reactor to reduce P 2 O 5 The dust content in the crude steam product further increases P 2 O 5 Purity of crude steam.
[0042] Step 400: Collect the P 2 O 5 The crude steam product is passed into the second reactor, and the temperature of the second reactor is raised to above 360°C and kept at this temperature for 30 to 60 minutes to obtain high-purity P 2 O 5 Steam. Preferably, the second reaction furnace is heated to a temperature higher than 360-500°C.
[0043] For example, a negative pressure device may be used to 2 O 5 Steam is sucked out from the top of the first reactor or the second reactor to achieve P 2 O 5 Collection of.
[0044] In the second reactor, P 2 O 5 The crude steam product can be further sublimated to reduce P 2 O 5 Dust content in steam to obtain high purity P 2 O 5 steam.
[0045] The method for preparing iron oxides and high-purity phosphorus pentoxide from phosphorus-containing and iron-containing wastes in the present application only requires the steps of melting, blowing, oxidation, and secondary sublimation. Compared with the related art that uses a wet process to recover iron and phosphorus from phosphorus-containing and iron-containing wastes, the method for preparing iron oxides and high-purity phosphorus pentoxide from phosphorus-containing and iron-containing wastes in the present application uses a pyrometallurgical process, which has the advantage of a simple process flow and can greatly reduce the amount of wastewater generated, thereby reducing or even omitting the cost of wastewater treatment; on the other hand, the use of a blowing feed method can allow the phosphorus in the phosphorus-containing and iron-containing wastes to fully contact with oxygen and generate phosphorus pentoxide, which is beneficial to improving the recovery rate of phosphorus pentoxide; at the same time, the phosphorus pentoxide generated by the combination of phosphorus and oxygen overflows in the form of steam, and the resulting phosphorus pentoxide has a purity of up to 99.9%, which can meet the demand for raw material purity in the battery field.
[0046] That is, the present application discloses a method for preparing iron oxide and high-purity phosphorus pentoxide from phosphorus- and iron-containing wastes. By adopting the above scheme, the technical problems in the related art of recovering phosphorus and iron from ferrophosphorus slag are solved, such as complicated steps, generation of a large amount of heavy metals or acidic wastewater, and difficulty in satisfying the purity of the product in meeting the requirements of the battery field.
[0047] Figure 2 The figure shows the equipment diagram for preparing iron oxide and high-purity phosphorus pentoxide from phosphorus- and iron-containing waste. Figure 2 As shown, the crushed phosphorus-containing and iron-containing waste is heated and melted in an induction furnace 200, and the melted phosphorus-containing and iron-containing waste is sprayed into the first reaction furnace 100 through a spray gun 300, and oxygen-containing gas is introduced from the bottom of the first reaction furnace 100. The phosphorus-containing and iron-containing waste reacts with oxygen to obtain P 2 O 5 Steam crude and iron oxides, P 2 O 5 The crude steam product is introduced into the absorption device 500 through the induced draft fan 400, and the iron oxides settle at the bottom of the first reaction furnace 100. Exemplarily, the absorption device 500 may be an absorption device containing sodium hydroxide liquid.
[0048] In some embodiments, the first reaction furnace is divided into a first reaction zone 110 and a second reaction zone 120, and the first reaction zone 110 is located above the second reaction zone 120. Figure 3 As shown. Preferably, the temperature of the second reaction zone 120 is controlled to be higher than the temperature of the first reaction zone 110. Preferably, the temperature of the second reaction zone 120 is controlled to be 50-100°C higher than the temperature of the first reaction zone 110. Exemplarily, the temperature of the first reaction zone 110 is controlled to be 500°C, and the temperature of the second reaction zone 120 is controlled to be 600°C.
[0049] In the method for preparing iron oxide and high-purity phosphorus pentoxide from phosphorus- and iron-containing wastes, the temperature at the bottom of the first reaction furnace is higher than the temperature at the top, which can promote the hot steam at the bottom to rise to the low-temperature zone at the top, thereby accelerating the phosphorus pentoxide reaction. 2 O 5 The steam migrates to the top in a directional manner. On the other hand, the temperature below is higher than that above, and centralized heating is provided below the first reactor, which helps to reduce energy consumption.
[0050] In some embodiments, when the molten phosphorus-containing and iron-containing waste is sprayed into the first reaction furnace by spraying with an atomizing nozzle, the material is sprayed downward from the top of the first reaction furnace, and the oxygen-containing gas is introduced upward from the bottom of the first reaction furnace. This feeding method allows the oxygen-containing gas to continuously collide with the falling molten material during the rising process, thereby improving the utilization rate of the oxygen-containing gas; on the other hand, the molten phosphorus-containing and iron-containing waste forms convection with the oxygen-containing gas, which can prolong the residence time of the molten phosphorus-containing and iron-containing waste in the furnace, thereby allowing the molten phosphorus-containing and iron-containing waste to react more fully with oxygen.
[0051] In some embodiments, the molten phosphorus- and iron-containing waste is sprayed obliquely downward into the first reaction furnace from above the first reaction furnace, such as Figure 3 Preferably, the atomizing nozzle is fixed on the wall surface of the first reaction furnace, and the spraying direction of the atomizing nozzle forms an angle of 30° to 60° with the inner wall of the first reaction furnace.
[0052] The present invention uses phosphorus-containing and iron-containing wastes to prepare iron oxides and high-purity phosphorus pentoxide. The molten phosphorus-containing and iron-containing wastes are sprayed into a first reaction furnace in an inclined downward manner. Compared with the vertical downward spraying direction, the inclined downward spraying method can make the molten phosphorus-containing and iron-containing wastes and the rising oxygen-containing gas form a spiral motion trajectory, induce forced turbulence, and improve the uniformity of mixing the molten phosphorus-containing and iron-containing wastes with oxygen, so that the molten phosphorus-containing and iron-containing wastes can react with oxygen more fully; and the centrifugal acceleration generated by the spiral motion can also reduce P 2 O 5 Dust, iron oxide particles, etc. carried in the steam can further increase P 2 O 5 On the other hand, the molten phosphorus-containing and iron-containing waste is sprayed into the first reaction furnace in an inclined downward manner, and the rising oxygen-containing gas can generate shear force on the falling phosphorus-containing and iron-containing waste, causing large droplets or large particles of the material to split into smaller particles, which can further increase the reaction rate and the yield of phosphorus pentoxide.
[0053] Example 1 The method of preparing iron oxide and high-purity phosphorus pentoxide from phosphorus- and iron-containing wastes in this embodiment comprises the following steps: Step 100: Using ferrophosphorus slag as raw material, crush it and pass it through a 200-mesh sieve, put the screened phosphorus- and iron-containing powders into a medium frequency furnace, first purge nitrogen to remove oxygen, and then use induction heating to 1200° C. to heat the phosphorus- and iron-containing powders to melt into a liquid state.
[0054] The molten phosphorus- and iron-containing waste is sprayed obliquely downward into the first reaction furnace, with the spraying direction forming an angle of 60° with the inner wall of the first reaction furnace, and air is introduced into the first reaction furnace at the same time.
[0055] Step 200: The first reaction zone of the first reaction furnace is heated to 600°C, and the second reaction zone is heated to 700°C, and the temperatures are kept for 40 minutes. The iron-containing waste reacts with oxygen to generate P 2 O 5 Steam crude and ferric oxide.
[0056] Step 300: After the reaction is completed, collect P from the top of the first reactor. 2 O 5 Steam crude product, ferric oxide, is collected from the bottom of the first reaction furnace.
[0057] Step 400: Collect the P 2 O 5 The crude steam product is passed into the second reactor, and the second reactor is heated to 400°C and kept warm for 40 minutes to obtain high-purity P 2 O 5 steam.
[0058] After testing, the recovery rate of phosphorus in this embodiment was 99.8%, P 2 O 5 The purity of ferrous metal is 99.9%, the recovery rate of iron is 99.2%, and the purity of ferric oxide is 75.2%.
[0059] Example 2 The method of preparing iron oxide and high-purity phosphorus pentoxide from phosphorus- and iron-containing wastes in this embodiment comprises the following steps: Step 100: Using ferrophosphorus slag as raw material, crush it and pass it through a 200-mesh sieve, put the screened phosphorus- and iron-containing powders into a medium frequency furnace, first purge nitrogen to remove oxygen, and then use induction heating to 1200° C. to heat the phosphorus- and iron-containing powders to melt into a liquid state.
[0060] The molten phosphorus- and iron-containing waste is sprayed obliquely downward into the first reaction furnace, with the spraying direction forming an angle of 60° with the inner wall of the first reaction furnace, and at the same time, a gas with an oxygen content of 18% is introduced into the first reaction furnace.
[0061] Step 200: The first reaction zone of the first reaction furnace is heated to 600°C, and the second reaction zone is heated to 700°C, and the temperatures are kept for 40 minutes. The iron-containing waste reacts with oxygen to generate P2 O 5 Steam crude and ferroferric oxide.
[0062] Step 300: After the reaction is completed, collect P from the top of the first reactor. 2 O 5 Steam crude product, ferrosoferric oxide, is collected from the bottom of the first reaction furnace.
[0063] Step 400: Collect the P 2 O 5 The crude steam product is passed into the second reactor, and the second reactor is heated to 400°C and kept warm for 40 minutes to obtain high-purity P 2 O 5 steam.
[0064] After testing, the recovery rate of phosphorus in this embodiment was 99.2%. 2 O 5 The purity of ferrous oxide is 99.4%, the recovery rate of iron is 99.5%, and the purity of ferroferric oxide is 78.9%.
[0065] Example 3 The method of preparing iron oxide and high-purity phosphorus pentoxide from phosphorus- and iron-containing wastes in this embodiment comprises the following steps: Step 100: Using ferrophosphorus slag as raw material, crush it and pass it through a 200-mesh sieve, put the screened phosphorus- and iron-containing powders into a medium frequency furnace, first purge nitrogen to remove oxygen, and then use induction heating to 1200° C. to heat the phosphorus- and iron-containing powders to melt into a liquid state.
[0066] The molten phosphorus- and iron-containing waste is sprayed obliquely downward into the first reaction furnace, with the spraying direction forming an angle of 60° with the inner wall of the first reaction furnace, and air is introduced into the first reaction furnace at the same time.
[0067] Step 200: The first reaction zone of the first reaction furnace is heated to 800°C, and the second reaction zone is heated to 900°C, and the temperatures are kept for 30 minutes. The iron-containing waste reacts with oxygen to generate P 2 O 5 Steam crude and ferric oxide.
[0068] Step 300: After the reaction is completed, collect P from the top of the first reactor. 2 O 5 Steam crude product, ferric oxide, is collected from the bottom of the first reaction furnace.
[0069] Step 400: Collect the P 2 O 5 The crude steam product is passed into the second reactor, and the second reactor is heated to 400°C and kept warm for 40 minutes to obtain high-purity P 2 O 5 steam.
[0070] After testing, the recovery rate of phosphorus in this embodiment was 99.3%. 2 O 5 The purity of ferrous oxide is 99.8%, the recovery rate of iron is 99.3%, and the purity of ferric oxide is 75.5%.
[0071] Example 4 The method of preparing iron oxide and high-purity phosphorus pentoxide from phosphorus- and iron-containing wastes in this embodiment comprises the following steps: Step 100: Using ferrophosphorus slag as raw material, crush it and pass it through a 200-mesh sieve, put the screened phosphorus- and iron-containing powders into a medium frequency furnace, first purge nitrogen to remove oxygen, and then use induction heating to 1200° C. to heat the phosphorus- and iron-containing powders to melt into a liquid state.
[0072] The molten phosphorus- and iron-containing waste is sprayed obliquely downward into the first reaction furnace, with the spraying direction forming an angle of 60° with the inner wall of the first reaction furnace, and air is introduced into the first reaction furnace at the same time.
[0073] Step 200: The first reaction zone of the first reaction furnace is heated to 360°C, and the second reaction zone is heated to 460°C. The temperatures are kept for 60 minutes. The iron-containing waste reacts with oxygen to generate P 2 O 5 Steam crude and ferric oxide.
[0074] Step 300: After the reaction is completed, collect P from the top of the first reactor. 2 O 5 Steam crude product, ferric oxide, is collected from the bottom of the first reaction furnace.
[0075] Step 400: Collect the P 2 O 5 The crude steam product is passed into the second reactor, and the second reactor is heated to 400°C and kept warm for 40 minutes to obtain high-purity P 2 O 5 steam.
[0076] After testing, the recovery rate of phosphorus in this embodiment is 99.5%, P 2 O 5 The purity of ferrous oxide is 99.2%, the recovery rate of iron is 99.6%, and the purity of ferric oxide is 74.8%.
[0077] Example 5 The method of preparing iron oxide and high-purity phosphorus pentoxide from phosphorus- and iron-containing wastes in this embodiment comprises the following steps: Step 100: Using ferrophosphorus slag as raw material, crush it and pass it through a 200-mesh sieve, put the screened phosphorus- and iron-containing powders into a medium frequency furnace, first purge nitrogen to remove oxygen, and then use induction heating to 1200° C. to heat the phosphorus- and iron-containing powders to melt into a liquid state.
[0078] The molten phosphorus- and iron-containing waste is sprayed obliquely downward into the first reaction furnace, with the spraying direction forming an angle of 30° with the inner wall of the first reaction furnace, and air is introduced into the first reaction furnace at the same time.
[0079] Step 200: The first reaction zone of the first reaction furnace is heated to 600°C, and the second reaction zone is heated to 700°C, and the temperatures are kept for 40 minutes. The iron-containing waste reacts with oxygen to generate P 2 O 5 Steam crude and ferric oxide.
[0080] Step 300: After the reaction is completed, collect P from the top of the first reactor. 2 O 5 Steam crude product, ferric oxide, is collected from the bottom of the first reaction furnace.
[0081] Step 400: Collect the P 2 O 5 The crude steam product is passed into the second reactor, and the second reactor is heated to 400°C and kept warm for 40 minutes to obtain high-purity P 2 O 5 steam.
[0082] After testing, the recovery rate of phosphorus in this embodiment was 99.6%, P 2 O 5 The purity of ferrous oxide is 99.7%, the recovery rate of iron is 98.8%, and the purity of ferric oxide is 75.3%.
[0083] Comparative Example 1 The method of preparing iron oxide and high-purity phosphorus pentoxide from phosphorus- and iron-containing wastes in this embodiment comprises the following steps: Step 100: Using ferrophosphorus slag as raw material, crush it and pass it through a 200-mesh sieve, put the screened phosphorus- and iron-containing powders into a medium frequency furnace, first purge nitrogen to remove oxygen, and then use induction heating to 1200° C. to heat the phosphorus- and iron-containing powders to melt into a liquid state.
[0084] The molten phosphorus- and iron-containing wastes are added into the first reaction furnace, and air is introduced into the first reaction furnace at the same time.
[0085] Step 200: The first reaction zone of the first reaction furnace is heated to 600°C, and the second reaction zone is heated to 700°C, and the temperatures are kept for 40 minutes. The iron-containing waste reacts with oxygen to generate P 2 O 5Steam crude and ferric oxide.
[0086] Step 300: After the reaction is completed, collect P from the top of the first reactor. 2 O 5 Steam crude product, ferric oxide, is collected from the bottom of the first reaction furnace.
[0087] Step 400: Collect the P 2 O 5 The crude steam product is passed into the second reactor, and the second reactor is heated to 400°C and kept warm for 40 minutes to obtain high-purity P 2 O 5 steam.
[0088] After testing, the recovery rate of phosphorus in this embodiment was 81.2%, P 2 O 5 The purity of ferrous oxide is 87.4%, the recovery rate of iron is 93.3%, and the purity of ferric oxide is 50.2%.
[0089] Comparative Example 2 Step 100: Using ferrophosphorus slag as raw material, crush it and pass it through a 200-mesh sieve, put the screened phosphorus- and iron-containing powders into a medium frequency furnace, first purge nitrogen to remove oxygen, and then use induction heating to 1200° C. to heat the phosphorus- and iron-containing powders to melt into a liquid state.
[0090] The molten phosphorus- and iron-containing waste is sprayed obliquely downward into the first reaction furnace, with the spraying direction forming an angle of 60° with the inner wall of the first reaction furnace, and air is introduced into the first reaction furnace at the same time.
[0091] Step 200: The first reaction zone and the second reaction zone of the first reaction furnace are heated to 700°C and kept warm for 40 minutes, and the iron-containing waste reacts with oxygen to generate P 2 O 5 Steam crude and ferric oxide.
[0092] Step 300: After the reaction is completed, collect P from the top of the first reactor. 2 O 5 Steam crude product, ferric oxide, is collected from the bottom of the first reaction furnace.
[0093] Step 400: Collect the P 2 O 5 The crude steam product is passed into the second reactor, and the second reactor is heated to 400°C and kept warm for 40 minutes to obtain high-purity P 2 O 5 steam.
[0094] After testing, the recovery rate of phosphorus in this embodiment was 85.7%, P 2 O 5The purity of ferrous oxide is 86.6%, the recovery rate of iron is 94.1%, and the purity of ferric oxide is 51.4%.
[0095] Comparative Example 3 The method of preparing iron oxide and high-purity phosphorus pentoxide from phosphorus- and iron-containing wastes in this embodiment comprises the following steps: Step 100: Using ferrophosphorus slag as raw material, crush it and pass it through a 200-mesh sieve, put the screened phosphorus- and iron-containing powders into a medium frequency furnace, first purge nitrogen to remove oxygen, and then use induction heating to 1200° C. to heat the phosphorus- and iron-containing powders to melt into a liquid state.
[0096] The molten phosphorus- and iron-containing waste is sprayed obliquely downward into the first reaction furnace, with the spraying direction being parallel to the inner wall of the first reaction furnace (maintaining vertical downward spraying), and air is introduced into the first reaction furnace at the same time.
[0097] Step 200: The first reaction zone of the first reaction furnace is heated to 600°C, and the second reaction zone is heated to 700°C, and the temperatures are kept for 40 minutes. The iron-containing waste reacts with oxygen to generate P 2 O 5 Steam crude and ferric oxide.
[0098] Step 300: After the reaction is completed, collect P from the top of the first reactor. 2 O 5 Steam crude product, ferric oxide, is collected from the bottom of the first reaction furnace.
[0099] Step 400: Collect the P 2 O 5 The crude steam product is passed into the second reactor, and the second reactor is heated to 400°C and kept warm for 40 minutes to obtain high-purity P 2 O 5 steam.
[0100] After testing, the recovery rate of phosphorus in this embodiment was 86.9%, P 2 O 5 The purity of ferrous oxide is 84.8%, the recovery rate of iron is 92.8%, and the purity of ferric oxide is 59.6%.
[0101] In the above-mentioned embodiments and comparative examples, the quinoline molybdate gravimetric method was used to detect the phosphorus pentoxide content, and the phosphorus recovery rate was calculated based on the ratio of the obtained phosphorus content to the phosphorus content in the ferrophosphorus slag.
[0102] The purity of phosphorus pentoxide was tested by quinomolybdate gravimetric method.
[0103] The iron content of the iron oxide was measured by potassium dichromate titration, and the iron recovery rate was calculated based on the ratio of the obtained iron content to the iron content in the ferrophosphorus slag.
[0104] The purity of iron oxides was determined by atomic absorption spectroscopy.
[0105] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element.
[0106] In addition, it should be noted that the scope of the methods and devices in the embodiments of the present application is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in a reverse order according to the functions involved. For example, the described methods may be performed in an order different from that described, and various steps may be added, omitted, or combined. In addition, features described with reference to certain examples may be combined in other examples.
[0107] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.
Claims
1. A method for preparing iron oxide and high-purity phosphorus pentoxide using phosphorus- and iron-containing wastes, characterized in that: The steps include: After crushing the solid phosphorus-containing and iron-containing waste, heat and melt it in an inert environment, and spray the melted phosphorus-containing and iron-containing waste into the first reaction furnace by blowing, or spray the liquid phosphorus-containing and iron-containing waste into the first reaction furnace by blowing; at the same time, oxygen-containing gas is introduced into the first reaction furnace; The first reaction furnace is heated to 360-900°C and kept at this temperature for 30-60 minutes, and phosphorus-containing and iron-containing waste reacts with oxygen to obtain crude P2O5 steam and iron oxides; Collect crude P2O5 steam from the top of the first reaction furnace, and collect iron oxide from the bottom of the first reaction furnace; The collected crude P2O5 steam is introduced into the second reaction furnace, and the second reaction furnace is heated to above 360°C and kept warm for 30 to 60 minutes to obtain high-purity P2O5 steam.
2. The method for preparing iron oxide and high-purity phosphorus pentoxide using phosphorus-containing and iron-containing wastes according to claim 1, characterized in that: The first reaction furnace is heated to 400-700°C.
3. The method for preparing iron oxide and high-purity phosphorus pentoxide using phosphorus-containing and iron-containing wastes according to claim 1, characterized in that: The first reaction furnace is divided into a first reaction zone and a second reaction zone. The first reaction zone is located above the second reaction zone, and the temperature of the second reaction zone is controlled to be higher than the temperature of the first reaction zone.
4. The method for preparing iron oxide and high-purity phosphorus pentoxide using phosphorus-containing and iron-containing wastes according to claim 3, characterized in that: The temperature of the second reaction zone is controlled to be 50-100° C. higher than the temperature of the first reaction zone.
5. The method for preparing iron oxide and high-purity phosphorus pentoxide using phosphorus-containing and iron-containing wastes according to any one of claims 1 to 4, characterized in that: When the melted phosphorus- and iron-containing waste is sprayed into the first reaction furnace by atomizing nozzle spraying, the material is sprayed downward from the top of the first reaction furnace, and the oxygen-containing gas is introduced upward from the bottom of the first reaction furnace.
6. The method for preparing iron oxide and high-purity phosphorus pentoxide using phosphorus-containing and iron-containing wastes according to claim 5, characterized in that: The atomizing nozzle is fixed on the wall surface of the first reaction furnace, and the spraying direction of the atomizing nozzle forms an angle of 30° to 60° with the inner wall of the first reaction furnace.
7. The method for preparing iron oxide and high-purity phosphorus pentoxide using phosphorus-containing and iron-containing wastes according to any one of claims 1 to 4, characterized in that: The phosphorus- and iron-containing waste is one or more of ferrophosphorus slag, high-phosphorus molten iron, yellow ferrophosphorus slag, and ferrophosphorus ore.
8. The method for preparing iron oxide and high-purity phosphorus pentoxide using phosphorus- and iron-containing wastes according to claim 7, characterized in that: For solid phosphorus and iron-containing waste, crush it to 200~500 mesh and then heat and melt it in an inert environment.
9. The method for preparing iron oxide and high-purity phosphorus pentoxide using phosphorus-containing and iron-containing wastes according to claim 8, characterized in that: The heating method is one or more of induction heating, microwave heating, fuel combustion heating, arc heating, plasma heating, and roasting heating.
10. The method for preparing iron oxide and high-purity phosphorus pentoxide using phosphorus-containing and iron-containing wastes according to any one of claims 1 to 4, characterized in that: When oxygen-containing gas is introduced into the first reaction furnace, when the oxygen concentration is lower than 21%, the obtained iron oxide is trimer tetroxide; when the oxygen concentration is equal to or higher than 21%, the obtained iron oxide is ferric oxide.