Method and device for preparing yellow phosphorus by smelting phosphate rock

Abstract

The application discloses a method and device for preparing yellow phosphorus by smelting phosphate rock, and the method comprises the following steps: crushing the phosphate rock to obtain mineral materials; mixing the mineral materials with flux to obtain mixed materials, and performing smelting treatment on the mixed materials in an oxygen-enriched side-blown smelting furnace to obtain liquid slag; performing reduction treatment on the liquid slag in a side-blown reduction smelting furnace to obtain phosphorus-containing flue gas; and sequentially performing waste heat recovery treatment and condensation treatment on the phosphorus-containing flue gas to obtain the yellow phosphorus. Thus, the phosphate rock can be smelted at low energy consumption by means of oxygen-enriched side-blown smelting and side-blown reduction smelting, and the phosphorus-containing flue gas can be recycled in a high-value mode through waste heat recovery treatment.

Description

Technical Field

[0001] This application relates to the field of phosphate rock smelting, and more specifically, to a method and apparatus for preparing yellow phosphorus by smelting phosphate rock. Background Technology

[0002] In nature, phosphorus resources mostly exist in the form of phosphate minerals. Phosphorus in phosphate rock is primarily apatite, which can be further divided into fluorapatite [Ca5(PO4)3F], hydroxyapatite [Ca5(PO4)3(OH)], and chloroapatite [Ca5(PO4)3Cl], often accompanied by dolomite, quartz, feldspar, pyrite, and other substances. Due to the very tight bond between phosphorus and oxygen in phosphate, the extraction of yellow phosphorus is quite complex. Currently, the mainstream process for yellow phosphorus extraction is the electric furnace smelting method. Phosphate rock, silica, and a carbonaceous reducing agent are mixed in a specific ratio and added to an electric furnace. At a smelting temperature above 1400℃, while maintaining a strong reducing atmosphere, the melt undergoes a reduction reaction, resulting in flue gas and phosphorus mud (slag). The flue gas mainly contains gasified yellow phosphorus and CO. After separation and purification, yellow phosphorus products and CO-rich yellow phosphorus tail gas can be obtained separately. Because of the strong reducing atmosphere maintained within the furnace, this process produces yellow phosphorus tail gas with a high CO content (85%–95%) along with the yellow phosphorus itself. Currently, most companies directly burn this tail gas, resulting in a huge waste of CO resources and CO2 greenhouse gas emissions. Simultaneously, to maintain a high smelting temperature and thermal balance, electrode heating is required for supplemental heating. Currently, the electricity consumption for producing one ton of yellow phosphorus is approximately 13,000–15,000 kW·h. The heat consumed by the reduction reaction and the heat carried away by the slag account for more than 80% of the total energy consumption, resulting in significant energy waste. Therefore, the method of producing yellow phosphorus from phosphate rock smelting still needs further improvement.

[0003] It should be noted that the above statements are only used to provide background information related to this application and do not necessarily constitute prior art. Summary of the Invention

[0004] In a first aspect, this application proposes a method for preparing yellow phosphorus by smelting phosphate rock, comprising: crushing phosphate rock to obtain ore; mixing the ore with a flux to obtain a mixture; melting the mixture in an oxygen-enriched side-blown smelting furnace to obtain liquid slag; reducing the liquid slag in a side-blown reduction smelting furnace to obtain phosphorus-containing flue gas; and sequentially subjecting the phosphorus-containing flue gas to waste heat recovery and condensation treatment to obtain the yellow phosphorus. Thus, this application achieves low-energy smelting of phosphate rock by combining oxygen-enriched side-blown melting with side-blown reduction smelting, while simultaneously achieving high-value recovery of phosphorus-containing flue gas through waste heat recovery treatment.

[0005] In some embodiments, the particle size of the ore is no greater than 30 mm. Therefore, the time required for complete melting of the ore is shorter, which helps to improve production efficiency.

[0006] In some embodiments, the basicity of the molten slag is 1.2 to 1.4. This helps to improve the desulfurization and dephosphorization capabilities of the molten slag while maintaining good fluidity.

[0007] In some embodiments, the flux includes at least one of quartz, river sand, and glass slag. This helps to lower the melting point of the ore and improve the fluidity of the liquid slag.

[0008] In some embodiments, the fuel used in the melting process includes pulverized coal or natural gas. This helps to reduce production costs and energy consumption.

[0009] In some embodiments, the reduction process uses pulverized coal or natural gas as fuel. This helps to reduce production costs and energy consumption.

[0010] In some embodiments, fuel is injected into the oxygen-enriched side-blown melting furnace using a first injection assembly; wherein the first injection assembly includes a first fuel channel and a first oxygen-enriched air channel, the first fuel channel being used for injecting fuel and the first oxygen-enriched air channel being used for injecting oxygen-enriched air. This facilitates efficient submerged combustion, with heat directly absorbed by the melt and minimal heat loss.

[0011] In some embodiments, the oxygen concentration in the oxygen-enriched air is 55% to 65%; and / or, the oxygen excess coefficient of the gas in the oxygen-enriched side-blown melting furnace is not less than 1.3. This is beneficial for increasing combustion temperature and reaction rate, saving fuel, and reducing energy consumption.

[0012] In some embodiments, the melting temperature is 1450°C to 1550°C. This helps to increase the melting rate of the ore and improve the fluidity of the molten slag, facilitating the discharge of the molten slag.

[0013] In some embodiments, the reduction treatment is performed at a temperature of 1400°C to 1700°C. This helps to promote the reduction of phosphorus.

[0014] In some embodiments, the reducing agent used in the reduction treatment includes at least one of granular coal, semi-coke, and natural gas; wherein the particle size of the granular coal and semi-coke is 1 mm to 10 mm; the molten slag enters the side-blown reduction smelting furnace via a chute; and / or, the reducing agent is sprayed into the molten slag through a reducing agent spray gun. This increases the contact area between the reducing agent and the molten slag, allowing the reduction reaction to proceed more uniformly and fully, thereby improving the reduction efficiency.

[0015] In some embodiments, fuel is injected into the side-blown reduction smelting furnace using a second injection assembly. The second injection assembly includes a second fuel channel and a second oxygen-enriched air channel. The second fuel channel is used for injecting fuel, and the second oxygen-enriched air channel is used for injecting oxygen-enriched air. The oxygen-enriched air has an oxygen permeability coefficient of 1.05 to 1.1. In some embodiments, the oxygen permeability coefficient of the gas in the side-blown reduction smelting furnace is 0.85 to 0.95. This helps maintain heat balance within the furnace and keeps the overall atmosphere in the furnace in a slightly reducing state.

[0016] In some embodiments, the waste heat recovery treatment includes: passing the phosphorus-containing flue gas sequentially through a first vaporization flue, a first high-temperature cyclone dust collector, a second high-temperature cyclone dust collector, a second vaporization flue, and a fire-tube evaporator. Thus, the steam generated through the waste heat recovery treatment can be used in a waste heat power generation system for energy recovery. The cooled phosphorus-containing flue gas contains fewer impurities, which helps improve the recovery efficiency of yellow phosphorus.

[0017] In some embodiments, the first vaporization flue is used to reduce the temperature of the phosphorus-containing flue gas to 800°C to 900°C; and / or, the first high-temperature cyclone dust collector is used to capture dust and ignition sources in the phosphorus-containing flue gas. This helps to reduce the risk of subsequent flue gas explosions caused by the temperature reduction.

[0018] In some embodiments, the second high-temperature cyclone dust collector is used to capture dust in phosphorus-containing flue gas; and / or, the second vaporization flue is used to reduce the temperature of phosphorus-containing flue gas to 600°C~700°C. This helps to reduce the pressure on subsequent flue gas dust removal and purification.

[0019] In some embodiments, the temperature of the phosphorus-containing flue gas at the outlet of the fire-tube evaporator is 400°C to 500°C. This facilitates the recovery of as much heat as possible, while allowing most of the yellow phosphorus to remain in a gaseous state and pass through the evaporator with the fire-tube flue gas, thereby increasing the total yield of yellow phosphorus.

[0020] In a second aspect of this application, an apparatus is provided for preparing yellow phosphorus by smelting phosphate rock according to the method described in the first aspect of this application, comprising: an oxygen-enriched side-blown smelting furnace having a mixed material inlet, a first blowing assembly, and a liquid slag outlet, wherein the oxygen-enriched side-blown smelting furnace is used to perform oxygen-enriched side-blown melting treatment on the phosphorus-containing mixed material to obtain liquid slag; a hot transfer channel having an inlet connected to the liquid slag outlet; a side-blown reduction smelting furnace having a liquid slag inlet connected to the outlet of the hot transfer channel, a reduction treatment assembly, and a phosphorus-containing flue gas outlet, wherein the side-blown reduction smelting furnace is used to perform reduction treatment on the liquid slag to obtain phosphorus-containing flue gas; a waste heat recovery device connected to the phosphorus-containing flue gas outlet for performing waste heat recovery treatment on the phosphorus-containing flue gas; and a condensation device connected to the waste heat recovery device for performing condensation treatment on the phosphorus-containing flue gas after waste heat recovery treatment to obtain yellow phosphorus. Therefore, the device for producing yellow phosphorus by smelting phosphate rock has the advantages of low energy consumption, high resource utilization rate, low production cost, and low pollution.

[0021] In some embodiments, the apparatus further includes a raw material supply device for supplying a mixture of phosphate rock and flux to the mixture inlet. This allows the mixture to be conveyed to an oxygen-enriched side-blown smelting furnace.

[0022] In some embodiments, the first injection assembly includes a first fuel channel and a first oxygen-enriched air channel, respectively used to inject first fuel and oxygen-enriched air into the oxygen-enriched side-blown smelting furnace. This helps to achieve efficient submerged combustion, with heat directly absorbed by the melt and low heat loss.

[0023] In some embodiments, the hot transfer channel is a chute. This facilitates the efficient transfer of high-temperature liquid slag.

[0024] In some embodiments, the reduction processing assembly includes a reducing agent addition section and a reheating section. The reducing agent addition section is used to add a reducing agent to the molten slag, and the reheating section is used to supply heat to the side-blown reduction smelting furnace. This helps to maintain the heat balance inside the furnace and keeps the overall atmosphere inside the furnace in a slightly reducing state.

[0025] In some embodiments, the reducing agent addition section is a reducing agent spray gun, used to spray the reducing agent into the liquid slag; the reheating section includes a second injection assembly, the second injection assembly including a second fuel channel and a second oxygen-enriched gas channel, used to inject a second fuel and an oxygen-enriched gas into the side-blown reduction smelting furnace, respectively. This facilitates the reduction reaction.

[0026] In some embodiments, the waste heat recovery device includes a first vaporization flue, a first high-temperature cyclone dust collector, a second high-temperature cyclone dust collector, a second vaporization flue, and a fire-tube evaporator connected in sequence. Thus, the steam generated by the waste heat recovery device can be used in a waste heat power generation system for energy recovery. The cooled phosphorus-containing flue gas contains fewer impurities, which helps improve the recovery efficiency of yellow phosphorus.

[0027] In some embodiments, the fire-facing surfaces of the first and second vaporization flues are provided with wear-resistant weld overlays of nickel-based or cobalt-based special materials, with a weld overlay thickness of 2mm to 8mm. The first and second vaporization flues are configured with a herringbone structure, and the water-cooled wall flues of the first and second vaporization flues are in the form of Ω-tubes. This helps to reduce the corrosion of the equipment caused by gases such as hydrogen fluoride in phosphorus-containing flue gas during the smelting process.

[0028] In some embodiments, the apparatus further includes a tail gas collection device connected to the tail gas outlet of the condensation device, which supplies the condensed tail gas to the oxygen-enriched side-blown smelting furnace and / or the side-blown reduction smelting furnace as fuel. This enables energy recovery and utilization, which helps reduce production costs. Attached Figure Description

[0029] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, wherein, Figure 1 This is a process flow diagram of preparing yellow phosphorus by smelting phosphate rock according to one embodiment of this application; Figure 2 This is a connection layout diagram of a phosphorus-containing flue gas waste heat recovery system according to an embodiment of this application.

[0030] Explanation of reference numerals in the attached figures: 1-Phosphorus-containing flue gas, 2-First vaporization flue, 3-First high-temperature cyclone dust collector, 4-Second high-temperature cyclone dust collector, 5-Second vaporization flue, 6-Fire tube evaporator. Detailed Implementation

[0031] The embodiments of this application are described in detail below, with examples of these embodiments shown in the accompanying drawings. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0032] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used in this application is for the purpose of describing particular embodiments only and is not intended to limit the application; unless otherwise stated, the values ​​of the parameters mentioned in this application can be measured using various measurement methods commonly used in the art (in the embodiments and comparative examples of this application, the total direct recovery rate of yellow phosphorus is calculated based on the total amount of phosphorus in the phosphate rock fed into the furnace, according to the amount of phosphorus in the final yellow phosphorus product. The comprehensive energy consumption is obtained by converting fuel consumption, electricity consumption, and waste heat recovery into energy consumption per unit of yellow phosphorus product. Unless otherwise stated, all contents are mass percentages).

[0033] The terms “comprising” and “having”, and any variations thereof, in the specification and claims of this application are open-ended expressions, meaning they include what is specified in this application but do not exclude other aspects.

[0034] In the description of this application, all figures disclosed herein, whether or not the words "approximately" or "about" are used, are approximate values. Each figure may vary by less than 10% or by a difference that is considered reasonable by one of the art, such as 1%, 2%, 3%, 4%, or 5%.

[0035] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60~120 and 80~110 are listed for a specific parameter, it is also expected that ranges of 60~110 and 80~120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1~3, 1~4, 1~5, 2~3, 2~4, and 2~5. In this application, unless otherwise stated, the numerical range "a~b" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0~5" indicates that all real numbers between "0~5" have been listed in this article; "0~5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0036] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. "First feature" and "second feature" may include one or more of the indicated feature.

[0037] In the description of this application, "A and / or B" can include any of the cases of A alone, B alone, or A and B, where A and B are merely examples and can be any technical feature connected by "and / or" in this application.

[0038] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0039] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0040] In the first aspect of this application, a method for preparing yellow phosphorus by smelting phosphate rock is proposed. This application utilizes oxygen-enriched side-blown molten feed combined with side-blown reduction smelting to process phosphate rock, achieving low-energy smelting of phosphate rock. Simultaneously, by recovering waste heat from the phosphorus-containing flue gas, high-value recovery of the phosphorus-containing flue gas is achieved. Specifically, refer to... Figure 1 The method includes: S1: The phosphate rock is crushed to obtain the ore.

[0041] In some embodiments, the particle size of the ore is no greater than 30 mm, for example, it can be 1 mm, 5 mm, 10 mm, 15 mm, 20 mm, 25 mm or 30 mm, etc. Therefore, the time required for the ore to completely melt is shorter, which is beneficial to improving production efficiency.

[0042] As an example, after the phosphate rock is dried, it is processed into ore with a particle size of no more than 30 mm by a cone crusher and a jaw crusher, and then conveyed to the batching silo by a belt.

[0043] S2: The ore and flux are mixed to obtain a mixture, which is then melted in an oxygen-enriched side-blown smelting furnace to obtain liquid slag.

[0044] In some embodiments, the flux includes at least one of quartz, river sand, and glass slag. This helps to lower the melting point of the ore and improve the fluidity of the liquid slag.

[0045] In some embodiments, the basicity of the liquid slag is 1.2 to 1.4, for example, it can be 1.2, 1.25, 1.3, 1.35, or 1.4. The basicity of the liquid slag refers to the mass ratio of calcium oxide to silicon dioxide in the liquid slag. This helps to improve the desulfurization and dephosphorization capabilities of the liquid slag while maintaining good fluidity.

[0046] As an example, quartz is added to the batching bin according to the basicity of the liquid slag being 1.2~1.4 through bin batching. The prepared mixture is then fed into the oxygen-enriched side-blown smelting furnace by a feeder for the melting process.

[0047] In some embodiments, the fuel used in the melting process includes pulverized coal or natural gas. This helps to reduce production costs and energy consumption.

[0048] In some embodiments, fuel is injected into the oxygen-enriched side-blown melting furnace using a first injection assembly; wherein the first injection assembly includes a first fuel channel and a first oxygen-enriched air channel, the first fuel channel being used for injecting fuel, and the first oxygen-enriched air channel being used for injecting oxygen-enriched air. The injection gun can be a submerged fuel injection gun. This helps to achieve efficient submerged combustion, with heat directly absorbed by the melt and low loss.

[0049] In some embodiments, the oxygen concentration in the oxygen-enriched air is 55% to 65%, for example, it can be 55%, 58%, 60%, 63%, or 65%; and / or, the oxygen permeability coefficient of the gas in the oxygen-enriched side-blown melting furnace is not less than 1.3, for example, it can be 1.3, 1.35, 1.3, 1.45, 1.5, 1.55, or 1.6. This is beneficial for increasing combustion temperature and reaction rate, saving fuel, and reducing energy consumption.

[0050] In this application, the oxygen coefficient refers to the ratio of the actual amount of air supplied during fuel combustion to the theoretical amount of air.

[0051] In some embodiments, the melting temperature is 1450℃~1550℃, for example, it can be 1450℃, 1470℃, 1490℃, 1510℃, 1520℃, 1530℃ or 1550℃. This helps to increase the melting rate of the ore, while improving the fluidity of the molten slag, which is beneficial for the discharge of the molten slag.

[0052] The above-mentioned oxygen-enriched side-blown smelting process for melting phosphate rock under a strong oxidizing atmosphere utilizes the advantage of the oxygen-enriched side-blown furnace's wide adaptability to the feed materials, greatly simplifying the raw material pretreatment process. Simultaneously, the high-temperature operation effectively removes low-melting-point impurities such as fluorine, chlorine, and arsenic from the raw ore, simplifying the purification process of phosphorus vapor condensation and recovery.

[0053] S3: The liquid slag is reduced in a side-blown reduction smelting furnace to obtain phosphorus-containing flue gas.

[0054] In some embodiments, the reduction process uses pulverized coal or natural gas as fuel. This helps to reduce production costs and energy consumption.

[0055] In some embodiments, fuel is injected into the side-blown reduction smelting furnace using a second injection assembly. The second injection assembly includes a second fuel channel and a second oxygen-enriched air channel. The second fuel channel is used for injecting fuel, and the second oxygen-enriched air channel is used for injecting oxygen-enriched air. The oxygen-enriched air has an oxygen permeability coefficient of 1.05 to 1.1, for example, 1.05, 1.06, 1.07, 1.08, 1.09, or 1.1. In some embodiments, the oxygen permeability coefficient of the gas in the side-blown reduction smelting furnace is 0.85 to 0.95, for example, 0.85, 0.87, 0.89, 0.91, 0.93, or 0.95. This helps maintain the heat balance within the furnace and keeps the overall atmosphere in the furnace in a slightly reducing state.

[0056] In some embodiments, the reduction treatment temperature is 1400℃~1700℃, for example, 1400℃, 1450℃, 1500℃, 1550℃, 1650℃ or 1700℃. This helps to promote the reduction of phosphorus.

[0057] In some embodiments, the reducing agent used in the reduction treatment includes at least one of granular coal, semi-coke, and natural gas; wherein the particle size of the granular coal and semi-coke is 1mm to 10mm, for example, it can be 1mm, 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, or 10mm, etc. This helps to increase the contact area between the reducing agent and the molten slag, allowing the reduction reaction to proceed more uniformly and fully, and improving the reduction efficiency.

[0058] In some embodiments, the molten slag enters the side-blown reduction smelting furnace via a chute; and / or, the reducing agent is sprayed into the molten slag through a reducing agent spray gun.

[0059] In some embodiments, the reducing agent is sprayed into the liquid slag from the tuyeres on the side wall of the furnace through a reducing agent spray gun (the coal-carrying air is nitrogen).

[0060] In this step, the molten slag produced in step S2 enters a side-blown reduction smelting furnace via a chute for phosphorus reduction and volatilization. The main reactions occurring in this process are as follows: 2Ca 10 (PO4)6F2+30C+2SiO2=3P4(g)↑+30CO(g)↑+18CaO·2SiO2+2CaF2 C + 1 / 2O₂(g)↑ = CO(g)↑ This application employs a side-blown furnace for the reduction smelting of high-temperature liquid phosphate slag. After melting in an oxygen-enriched side-blown furnace, the resulting liquid slag is discharged through a slag discharge port and flows into a side-blown reduction smelting furnace via a chute for further reduction reaction. During this process, a slightly reducing atmosphere is maintained inside the furnace. Because high-temperature liquid slag is being processed, the sensible heat of the liquid slag can be fully utilized, effectively reducing energy consumption.

[0061] S4: The phosphorus-containing flue gas is subjected to waste heat recovery treatment and condensation treatment in sequence to obtain the yellow phosphorus.

[0062] In some embodiments, refer to Figure 2 The waste heat recovery treatment includes: passing the phosphorus-containing flue gas 1 sequentially through a first vaporization flue 2, a first high-temperature cyclone dust collector 3, a second high-temperature cyclone dust collector 4, a second vaporization flue 5, and a fire-tube evaporator 6. Thus, the steam generated through the waste heat recovery treatment can be used in a waste heat power generation system for energy recovery. The cooled phosphorus-containing flue gas contains fewer impurities, which helps improve the recovery efficiency of yellow phosphorus.

[0063] In some embodiments, the first vaporization flue is used to reduce the temperature of the phosphorus-containing flue gas to 800°C to 900°C; and / or, the first high-temperature cyclone dust collector is used to capture dust and ignition sources in the phosphorus-containing flue gas. This helps to reduce the risk of subsequent flue gas explosions caused by the temperature reduction.

[0064] In some embodiments, the second high-temperature cyclone dust collector is used to capture dust in phosphorus-containing flue gas; and / or, the second vaporization flue is used to reduce the temperature of phosphorus-containing flue gas to 600°C~700°C. This helps to reduce the pressure on subsequent flue gas dust removal and purification.

[0065] In some embodiments, the temperature of the phosphorus-containing flue gas at the outlet of the fire-tube evaporator is 400°C to 500°C. This facilitates the recovery of as much heat as possible, while allowing most of the yellow phosphorus to remain in a gaseous state and pass through the evaporator with the fire-tube flue gas, thereby increasing the total yield of yellow phosphorus.

[0066] As an example, refer to Figure 1 The method for preparing yellow phosphorus by smelting phosphate rock in this application includes the following process: (1) After drying the phosphate rock, it is processed into ore with a particle size of no more than 30 mm by a cone crusher and a jaw crusher. The ore is then conveyed to the batching bin by a belt conveyor. Then, the silo batching is carried out, and flux is added according to the basicity of the liquid slag of 1.2~1.4. The prepared mixture is fed into the oxygen-enriched side-blown smelting furnace by a feeder for the melting process. After melting, flue gas and liquid slag are obtained. The flue gas is discharged after passing through a waste heat boiler, electrostatic precipitator and flue gas desulfurization to meet the emission standards.

[0067] (2) The liquid slag enters the side-blown reduction smelting furnace through the chute to carry out the reduction and volatilization process of phosphorus, thereby generating smelting slag and phosphorus-containing flue gas. The smelting slag is stored after water quenching, and the phosphorus-containing flue gas is processed by waste heat recovery, flue gas purification and condensation treatment to obtain yellow phosphorus.

[0068] Specifically, refer to Figure 2 Waste heat recovery treatment includes: (1) Phosphorus-containing flue gas 1 first passes through the first vaporization flue 2 to reduce the temperature to 800℃~900℃, and then enters the first high-temperature cyclone dust collector 3, which can capture large dust particles and sparks in the flue gas, reducing the risk of flue gas explosion due to subsequent temperature reduction.

[0069] (2) The phosphorus-containing flue gas after passing through the first high-temperature cyclone dust collector 3 enters the second high-temperature cyclone dust collector 4 to further capture the dust in the flue gas, which can greatly reduce the pressure of subsequent flue gas dust removal and purification. Then it enters the second vaporization flue 5 so that the temperature can be reduced to 600℃~700℃.

[0070] (3) The phosphorus-containing flue gas after passing through the second vaporization flue 5 enters the fire-tube evaporator 6, and the final flue gas outlet temperature is about 400℃~500℃. The steam generated by this waste heat recovery treatment can be used in the waste heat power generation system for energy recovery. The cooled phosphorus-containing flue gas is purified by dust collection and spray washing again before entering the condenser for yellow phosphorus condensation and recovery. The carbon monoxide tail gas generated at the end can be collected and stored in a gas holder after washing and purification, and then pressurized and used as fuel (it can be used to supplement the heat of the phosphate rock melting process in the oxygen-enriched side-blown smelting furnace).

[0071] In a second aspect of this application, an apparatus is provided for preparing yellow phosphorus by smelting phosphate rock according to the method described in the first aspect of this application, comprising: an oxygen-enriched side-blown smelting furnace having a mixed material inlet, a first blowing assembly, and a liquid slag outlet, wherein the oxygen-enriched side-blown smelting furnace is used to perform oxygen-enriched side-blown melting treatment on the phosphorus-containing mixed material to obtain liquid slag; a hot transfer channel having an inlet connected to the liquid slag outlet; a side-blown reduction smelting furnace having a liquid slag inlet connected to the outlet of the hot transfer channel, a reduction treatment assembly, and a phosphorus-containing flue gas outlet, wherein the side-blown reduction smelting furnace is used to perform reduction treatment on the liquid slag to obtain phosphorus-containing flue gas; a waste heat recovery device connected to the phosphorus-containing flue gas outlet for performing waste heat recovery treatment on the phosphorus-containing flue gas; and a condensation device connected to the waste heat recovery device for performing condensation treatment on the phosphorus-containing flue gas after waste heat recovery treatment to obtain yellow phosphorus. Therefore, the device for producing yellow phosphorus by smelting phosphate rock has the advantages of low energy consumption, high resource utilization rate, low production cost, and low pollution.

[0072] In some embodiments, the apparatus further includes a raw material supply device for supplying a mixture of phosphate rock and flux to the mixture inlet. This allows the mixture to be conveyed to an oxygen-enriched side-blown smelting furnace.

[0073] In some embodiments, the first injection assembly includes a first fuel channel and a first oxygen-enriched air channel, respectively used to inject first fuel and oxygen-enriched air into the oxygen-enriched side-blown smelting furnace. This helps to achieve efficient submerged combustion, with heat directly absorbed by the melt and low heat loss.

[0074] In some embodiments, the hot transfer channel is a chute. This facilitates the efficient transfer of high-temperature liquid slag.

[0075] In some embodiments, the reduction processing assembly includes a reducing agent addition section and a reheating section. The reducing agent addition section is used to add a reducing agent to the molten slag, and the reheating section is used to supply heat to the side-blown reduction smelting furnace. This helps to maintain the heat balance inside the furnace and keeps the overall atmosphere inside the furnace in a slightly reducing state.

[0076] In some embodiments, the reducing agent addition section is a reducing agent spray gun, used to spray the reducing agent into the liquid slag; the reheating section includes a second injection assembly, the second injection assembly including a second fuel channel and a second oxygen-enriched gas channel, used to inject a second fuel and an oxygen-enriched gas into the side-blown reduction smelting furnace, respectively. This facilitates the reduction reaction.

[0077] In some embodiments, the waste heat recovery device includes a first vaporization flue, a first high-temperature cyclone dust collector, a second high-temperature cyclone dust collector, a second vaporization flue, and a fire-tube evaporator connected in sequence. Thus, the steam generated by the waste heat recovery device can be used in a waste heat power generation system for energy recovery. The cooled phosphorus-containing flue gas contains fewer impurities, which helps improve the recovery efficiency of yellow phosphorus.

[0078] In some embodiments, the fire-facing surfaces of the first and second vaporization flues are provided with wear-resistant weld overlays of nickel-based or cobalt-based special materials, with a weld overlay thickness of 2mm to 8mm (e.g., 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, or 8mm). The first and second vaporization flues are configured with a herringbone structure, and the water-cooled wall flues of the first and second vaporization flues are in the form of Ω-tubes. This helps to reduce the corrosion of the equipment caused by gases such as hydrogen fluoride in the phosphorus-containing flue gas during the smelting process.

[0079] In some embodiments, the apparatus further includes a tail gas collection device connected to the tail gas outlet of the condensation device, which supplies the condensed tail gas to the oxygen-enriched side-blown smelting furnace and / or the side-blown reduction smelting furnace as fuel. This enables energy recovery and utilization, which helps reduce production costs.

[0080] The description of the various embodiments above tends to emphasize the differences between the various embodiments. The similarities or similarities between them can be referred to, and for the sake of brevity, they will not be repeated here.

[0081] The following specific embodiments illustrate the solution of this application. It should be noted that these embodiments are for illustrative purposes only and should not be considered as limiting the scope of this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0082] Example 1 A type of phosphate rock, the specific composition of which is shown in Table 1 below: Table 1

[0083] The aforementioned phosphate ore is used to produce yellow phosphorus through a process of "oxygen-enriched side-blown smelting + side-blown reduction smelting + flue gas waste heat recovery + flue gas scrubbing, purification, and condensation". The specific process is as follows: (1) Raw material pretreatment process: After drying the phosphate rock, it is processed into ore with a particle size of no more than 30 mm by a cone crusher and a jaw crusher. It is then conveyed to the batching bin by a belt conveyor. Quartz stone is added according to the basicity of the liquid slag of 1.2 (mass ratio of CaO to SiO2). The prepared mixture is fed into the oxygen-enriched side-blown smelting furnace by a feeder for the melting process.

[0084] (2) Oxygen-enriched side-blown melting stage: After the ore enters the oxygen-enriched side-blown melting furnace, it is melted at high temperature. The fuel is pulverized coal. The fuel is injected into the molten pool using a submerged combustion lance. The lance adopts a dual-channel structure. The inner channel is sprayed with pulverized coal (270 kg of coal per ton of ore), and the outer channel is sprayed with oxygen-enriched air (oxygen concentration of 60%). The oxygen coefficient α is controlled to be ≥1.3 to ensure that the melting temperature of the molten pool is 1500℃. The final product is a high-temperature liquid slag with a phosphorus content of 11.3% (equivalent to a P2O5 content of 25.89%) and a fluorine content of 0.05% (removal rate ≥95%).

[0085] (3) Side-blown reduction smelting process: The liquid slag produced in step (2) enters the side-blown reduction smelting furnace through the chute for the reduction and volatilization of phosphorus. The reducing agent is granular coal (average particle size of 3 mm), which is sprayed into the slag layer through a reducing agent spray gun (single channel). The amount of granular coal used is 1.2 times the theoretical amount, and the granular coal consumption per ton of ore is 85 kg. In order to maintain the heat balance in the furnace, a dual-channel combustion spray gun is used for supplementary heating. The fuel is pulverized coal, and the pulverized coal consumption per ton of ore is 45 kg. Oxygen-enriched air (oxygen concentration of 55%) is used as the external channel combustion air, and the oxygen coefficient is controlled between 1.05 and 1.1. At the same time, the overall atmosphere in the furnace is kept in a slightly reducing state (the oxygen coefficient α is between 0.9 and 0.95), and the furnace temperature is 1600℃. The final output includes ferrophosphate (0.18 tons of ferrophosphate per ton of ore), phosphorus-containing flue gas, and smelting slag. The phosphorus content in the slag is 0.5%, the phosphorus content in the ferrophosphate is 16%, and the elemental phosphorus content in the phosphorus-containing flue gas is 28%.

[0086] (4) Waste heat recovery treatment of phosphorus-containing flue gas and preparation of yellow phosphorus: The high-temperature flue gas containing CO (temperature of about 1200℃~1300℃) produced from the side-blown reduction smelting furnace passes through the first vaporization flue, the first high-temperature cyclone dust collector, the second high-temperature cyclone dust collector, the second vaporization flue, and the fire tube evaporator to complete waste heat recovery. The produced steam is sent to waste heat power generation. After waste heat recovery, the flue gas is processed through dust collection, condensation and other processes to produce yellow phosphorus with a purity of 98.5%. The phosphorus content in the yellow phosphorus tail gas is 0.01%, and the direct phosphorus recovery rate in this process is 99%.

[0087] According to calculations, the total direct recovery rate of yellow phosphorus produced using this process is 84%, and the comprehensive energy consumption for producing one ton of yellow phosphorus is approximately 10,500 kWh, which saves about 20% of energy compared to the conventional electric furnace method.

[0088] Example 2 The difference from Example 1 is as follows: (1) Raw material pretreatment process: After drying the phosphate rock, it is processed into ore with a particle size of no more than 30 mm by a cone crusher and a jaw crusher. It is then conveyed to the batching bin by a belt conveyor. Quartz stone is added according to the basicity of the liquid slag of 1.4 (mass ratio of CaO to SiO2). The prepared mixture is fed into the oxygen-enriched side-blown smelting furnace by a feeder for the melting process.

[0089] (2) Oxygen-enriched side-blown melting stage: After the ore enters the oxygen-enriched side-blown melting furnace, it is melted at high temperature. The fuel is pulverized coal. The fuel is injected into the molten pool using a submerged combustion lance. The lance adopts a dual-channel structure. The inner channel is sprayed with pulverized coal (280 kg of coal per ton of ore), and the outer channel is sprayed with oxygen-enriched air (oxygen concentration of 60%). The oxygen coefficient α is controlled to be ≥1.3 to ensure that the melting temperature of the molten pool is 1550℃. The final product is a high-temperature liquid slag with a phosphorus content of 12.6% (equivalent to a P2O5 content of 28.87%) and a fluorine content of 0.03% (removal rate ≥97%).

[0090] (3) Side-blown reduction smelting process: The liquid slag produced in step (2) enters the side-blown reduction smelting furnace through the chute for the reduction and volatilization of phosphorus. The reducing agent is granular coal (average particle size of 5 mm), which is sprayed into the slag layer through the reducing agent spray gun. The amount of granular coal used is 1.2 times the theoretical amount, and the granular coal consumption per ton of ore is 70 kg. In order to maintain the heat balance in the furnace, a dual-channel combustion spray gun is used for supplementary heating. The fuel is pulverized coal, and the pulverized coal consumption per ton of ore is 50 kg. Oxygen-enriched air (oxygen concentration of 60%) is used as the external channel combustion air, and the oxygen coefficient is controlled between 1.05 and 1.1. At the same time, the overall atmosphere in the furnace is in a slightly reducing state (the oxygen coefficient α is between 0.9 and 0.95), and the furnace temperature is 1450℃. The final output includes ferrophosphate (0.23 tons of ferrophosphate per ton of ore), phosphorus-containing flue gas, and smelting slag. The phosphorus content in the slag is 0.4%, the phosphorus content in the ferrophosphate is 14%, and the elemental phosphorus content in the phosphorus-containing flue gas is 29.5%.

[0091] (4) Waste heat recovery treatment of phosphorus-containing flue gas and preparation of yellow phosphorus: The high-temperature flue gas containing CO (temperature of about 1200℃~1300℃) produced from the side-blown reduction smelting furnace passes through the first vaporization flue, the first high-temperature cyclone dust collector, the second high-temperature cyclone dust collector, the second vaporization flue, and the fire tube evaporator to complete waste heat recovery. The produced steam is sent to waste heat power generation. After waste heat recovery, the flue gas is processed through dust collection, condensation and other processes to produce yellow phosphorus with a purity of 97.1%. The phosphorus content in the yellow phosphorus tail gas is 0.05%, and the direct phosphorus recovery rate in this process is 97.5%.

[0092] According to calculations, the total direct recovery rate of yellow phosphorus produced using this process is 82.5%, and the comprehensive energy consumption for producing one ton of yellow phosphorus is approximately 10,350 kWh, which saves about 24.5% of energy compared to the conventional electric furnace method.

[0093] Example 3 The difference from Example 1 is as follows: (1) Raw material pretreatment process: After drying the phosphate rock, it is processed into ore with a particle size of no more than 30 mm by a cone crusher and a jaw crusher. It is then conveyed to the batching bin by a belt conveyor. Quartz stone is added according to the basicity of the liquid slag of 1.35 (mass ratio of CaO to SiO2). The prepared mixture is fed into the oxygen-enriched side-blown smelting furnace by a feeder for the melting process.

[0094] (2) Oxygen-enriched side-blown melting stage: After the ore enters the oxygen-enriched side-blown melting furnace, it is melted at high temperature. The fuel is pulverized coal. The fuel is injected into the molten pool using a submerged combustion lance. The lance adopts a dual-channel structure. The inner channel is sprayed with pulverized coal (245 kg of coal per ton of ore), and the outer channel is sprayed with oxygen-enriched air (oxygen concentration of 55%). The oxygen coefficient α is controlled to be ≥1.2 to ensure that the melting temperature of the molten pool is 1500℃. The final product is a high-temperature liquid slag with a phosphorus content of 10.47% (equivalent to a P2O5 content of 23.98%) and a fluorine content of 0.08% (removal rate ≥92%).

[0095] (3) Side-blown reduction smelting process: The liquid slag produced in step (2) enters the side-blown reduction smelting furnace through the chute for the reduction and volatilization of phosphorus. The reducing agent is granular coal (average particle size of 1 mm), which is sprayed into the slag layer through the reducing agent spray gun. The amount of granular coal used is 1.2 times the theoretical amount, and the granular coal consumption per ton of ore is 90 kg. In order to maintain the heat balance in the furnace, a dual-channel combustion spray gun is used for supplementary heating. The fuel is pulverized coal, and the pulverized coal consumption per ton of ore is 60 kg. Oxygen-enriched air (oxygen concentration of 62%) is used as the external channel combustion air, and the oxygen coefficient is controlled between 1.05 and 1.1. At the same time, the overall atmosphere in the furnace is in a slightly reducing state (the oxygen coefficient α is between 0.9 and 0.95), and the furnace temperature is 1700℃. The final output includes ferrophosphate (0.23 tons of ferrophosphate per ton of ore), phosphorus-containing flue gas, and smelting slag. The phosphorus content in the slag is 0.4%, the phosphorus content in the ferrophosphate is 18%, and the elemental phosphorus content in the phosphorus-containing flue gas is 29.6%.

[0096] (4) Waste heat recovery treatment of phosphorus-containing flue gas and preparation of yellow phosphorus: The high-temperature flue gas containing CO (temperature of about 1200℃~1300℃) produced from the side-blown reduction smelting furnace passes through the first vaporization flue, the first high-temperature cyclone dust collector, the second high-temperature cyclone dust collector, the second vaporization flue, and the fire tube evaporator to complete waste heat recovery. The produced steam is sent to waste heat power generation. After waste heat recovery, the flue gas is processed through dust collection, condensation and other processes to produce yellow phosphorus with a purity of 98.8%. The phosphorus content in the yellow phosphorus tail gas is 0.01%, and the direct phosphorus recovery rate in this process is 98%.

[0097] According to calculations, the total direct recovery rate of yellow phosphorus produced using this process is 84%, and the comprehensive energy consumption for producing one ton of yellow phosphorus is approximately 11,000 kWh, which saves about 18% of energy compared to the conventional electric furnace method.

[0098] Comparative Example 1 The difference from Example 1 is as follows: (4) Phosphorus-containing flue gas was not treated by waste heat recovery. It directly produced yellow phosphorus with a purity of 95% after passing through dust collection, condensation and other processes. The phosphorus content in the yellow phosphorus tail gas was 0.5%. The direct phosphorus recovery rate in this process was 90%.

[0099] According to calculations, the total direct recovery rate of yellow phosphorus produced using this process is 75%, and the comprehensive energy consumption for producing one ton of yellow phosphorus is approximately 14,000 kWh.

[0100] Comparative Example 2 The difference from Example 1 is as follows: (3) The reduction smelting furnace is a side-blown + electric heating composite furnace. The liquid slag produced in step (2) enters the side-blown + electric heating composite reduction smelting furnace through a chute for the reduction and volatilization of phosphorus. Electrode heating is used, and the reducing agent is selected as granular coal (average particle size of 3mm). It is sprayed into the slag layer through a reducing agent spray gun. The amount of granular coal used is 1.2 times the theoretical amount, and the granular coal consumption per ton of ore is 70kg. Ensure that the overall atmosphere in the electric furnace is in a slightly reducing state (the oxygen coefficient α is between 0.9 and 0.95). Finally, ferrophosphate (the yield of ferrophosphate per ton of ore is 0.24 tons), phosphorus-containing flue gas, and smelting slag are produced. The phosphorus content in the slag is 0.35%, the phosphorus content in the ferrophosphate is 17.6%, and the elemental phosphorus content in the phosphorus-containing flue gas is 29.6%.

[0101] According to calculations, the total direct recovery rate of yellow phosphorus produced using this process is 85%, and the comprehensive energy consumption for producing one ton of yellow phosphorus is approximately 14,500 kWh.

[0102] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A method for preparing yellow phosphorus by smelting phosphate rock, characterized in that, include: The phosphate rock is crushed to obtain the ore. The ore and flux are mixed to obtain a mixture, which is then melted in an oxygen-enriched side-blown smelting furnace to obtain liquid slag. The liquid slag is reduced in a side-blown reduction smelting furnace to obtain phosphorus-containing flue gas; The phosphorus-containing flue gas is subjected to waste heat recovery treatment and condensation treatment in sequence to obtain the yellow phosphorus.

2. The method according to claim 1, characterized in that, The particle size of the mineral material is not greater than 30 mm; and / or, The basicity of the liquid slag is 1.2 to 1.

4.

3. The method according to claim 1 or 2, characterized in that, The flux includes at least one of quartz, river sand, and glass slag; The fuel used in the melting process includes pulverized coal or natural gas; The reduction process uses either pulverized coal or natural gas as fuel.

4. The method according to claim 1 or 2, characterized in that, Fuel is injected into the oxygen-enriched side-blown smelting furnace using a first injection assembly; wherein, the first injection assembly includes a first fuel channel and a first oxygen-enriched air channel, the first fuel channel being used for injecting fuel, and the first oxygen-enriched air channel being used for injecting oxygen-enriched air.

5. The method according to claim 4, characterized in that, The oxygen concentration in the oxygen-enriched air is 55%~65%; and / or, The oxygen peroxide coefficient of the gas inside the oxygen-enriched side-blown melting furnace is not less than 1.

3.

6. The method according to claim 1 or 2, characterized in that, The melting treatment temperature is 1450℃~1550℃; and / or, The reduction treatment temperature is 1400℃~1700℃.

7. The method according to claim 1 or 2, characterized in that, The reducing agent used in the reduction process includes at least one of granular coal, semi-coke, and natural gas; wherein the particle size of the granular coal and semi-coke is 1 mm to 10 mm. The molten slag enters the side-blown reduction smelting furnace via a chute; and / or The reducing agent used in the reduction process is sprayed into the liquid slag through a reducing agent spray gun.

8. The method according to claim 1 or 2, characterized in that, Fuel is injected into the side-blown reduction smelting furnace using a second injection assembly. The second injection assembly includes a second fuel channel and a second oxygen-enriched air channel. The second fuel channel is used to inject fuel, and the second oxygen-enriched air channel is used to inject oxygen-enriched air. The oxygen-enriched air has an oxygen permeability coefficient of 1.05 to 1.

1.

9. The method according to claim 8, characterized in that, The peroxide coefficient of the gas in the side-blown reduction smelting furnace is 0.85~0.

95.

10. The method according to claim 1 or 2, characterized in that, The waste heat recovery treatment includes: passing the phosphorus-containing flue gas sequentially through a first vaporization flue, a first high-temperature cyclone dust collector, a second high-temperature cyclone dust collector, a second vaporization flue, and a fire tube evaporator.

11. The method according to claim 10, characterized in that, The first vaporization flue is used to reduce the temperature of the phosphorus-containing flue gas to 800℃~900℃; and / or, The first high-temperature cyclone dust collector is used to capture dust and sparks in phosphorus-containing flue gas; and / or, The second high-temperature cyclone dust collector is used to capture dust in phosphorus-containing flue gas; and / or, The second vaporization flue is used to reduce the temperature of phosphorus-containing flue gas to 600°C~700°C; and / or, The temperature of the phosphorus-containing flue gas at the outlet of the fire-tube evaporator is 400℃~500℃.

12. An apparatus for preparing yellow phosphorus by smelting phosphate rock according to any one of claims 1 to 11, characterized in that, include: An oxygen-enriched side-blown melting furnace has a mixed material inlet, a first blowing assembly, and a liquid slag outlet. The oxygen-enriched side-blown melting furnace is used to perform oxygen-enriched side-blown melting treatment on phosphorus-containing mixed materials to obtain liquid slag. A hot transfer channel, the inlet of which is connected to the outlet of the molten slag; A side-blown reduction smelting furnace has a liquid slag inlet connected to the outlet of the hot transfer channel, a reduction treatment component, and a phosphorus-containing flue gas outlet. The side-blown reduction smelting furnace is used to reduce the liquid slag to obtain phosphorus-containing flue gas. A waste heat recovery device is connected to the phosphorus-containing flue gas outlet and is used to recover waste heat from the phosphorus-containing flue gas. A condensation device, connected to the waste heat recovery device, is used to condense the phosphorus-containing flue gas after waste heat recovery treatment to obtain yellow phosphorus.

13. The apparatus according to claim 12, characterized in that, The apparatus also includes a raw material supply device for supplying a mixture of phosphate rock and flux to the mixture inlet.

14. The apparatus according to claim 12 or 13, characterized in that, The first injection assembly includes a first fuel channel and a first oxygen-enriched air channel, which are used to inject first fuel and oxygen-enriched air into the oxygen-enriched side-blown smelting furnace, respectively.

15. The apparatus according to claim 12 or 13, characterized in that, The hot transfer channel is a chute.

16. The apparatus according to claim 12 or 13, characterized in that, The reduction processing assembly includes a reducing agent addition section and a reheating section. The reducing agent addition section is used to add the reducing agent to the liquid slag, and the reheating section is used to supply heat to the side-blown reduction smelting furnace.

17. The apparatus according to claim 16, characterized in that, The reducing agent addition section is a reducing agent spray gun, used to spray the reducing agent into the liquid slag; The reheating section includes a second injection assembly, which includes a second fuel channel and a second oxygen-enriched gas channel, respectively used to inject a second fuel and an oxygen-enriched gas into the side-blown reduction smelting furnace.

18. The apparatus according to claim 12 or 13, characterized in that, The waste heat recovery device includes a first vaporization flue, a first high-temperature cyclone dust collector, a second high-temperature cyclone dust collector, a second vaporization flue, and a fire tube evaporator connected in sequence; wherein, the fire-facing surfaces of the first vaporization flue and the second vaporization flue are provided with wear-resistant weld overlay of nickel-based or cobalt-based special materials, with a weld overlay thickness of 2mm~8mm, the first vaporization flue and the second vaporization flue are configured with a herringbone structure, and the water-cooled wall flues of the first vaporization flue and the second vaporization flue adopt the form of Ω tube.

19. The apparatus according to claim 12 or 13, characterized in that, The device also includes a tail gas collection device, which is connected to the tail gas outlet of the condensation device and is used to supply the condensed tail gas to the oxygen-enriched side-blown smelting furnace and / or the side-blown reduction smelting furnace as fuel.

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