A method for recovering ferrophosphorus as a by-product of yellow phosphorus produced by electric furnace process

Abstract

The present application relates to the recycling and utilization of ferrophosphorus resources, and specifically to a method for recovering ferrophosphorus, a by-product of yellow phosphorus produced by the electric furnace process. The present application uses a high-temperature oxidation roasting method to oxidatively roast phosphate ore and a ferrophosphorus composition, and adds silicon dioxide to adjust the alkalinity of the roasting raw materials to 1. During the roasting process, ferrophosphorus will undergo oxidative decomposition at high temperatures to produce Fe2O3 and P2O5. The entire decomposition process will release a large amount of heat to effectively supplement part of the energy required for the entire roasting process, thereby reducing the roasting temperature and reducing energy consumption. At the same time, the decomposed P2O5 serves as a supplementary phosphorus source, which increases the phosphorus content of the pellets after sintering, helping to reduce the energy consumption required for the next step of yellow phosphorus production. In addition, melting will occur before the ferrophosphorus decomposes during the roasting process, and the volume will expand slightly, so that the pellets after roasting have better bonding properties, higher strength, and increased voids, thereby obtaining pellets that are more conducive to the production of yellow phosphorus by the electric furnace process.

Description

Technical Field

[0001] The present application relates to the recycling and utilization of ferrophosphorus resources, and specifically to a method for recovering ferrophosphorus, a by-product of yellow phosphorus produced by an electric furnace process. Background Art

[0002] Ferrophosphorus slag is a waste product from the phosphorus production industry. Due to variations in raw materials and process conditions, its composition is complex, containing significant amounts of iron and phosphorus, with the combined content exceeding 80%. Iron typically accounts for 50% to 75%, while phosphorus accounts for 18% to 30%. It also contains a small amount of silicon, primarily in the form of SiO2. During the electric furnace process for yellow phosphorus production, 0.1 to 0.2 tons of ferrophosphorus byproduct is generated for every ton of yellow phosphorus produced. While a small amount is used as a raw material for steelmaking and phosphate production, the majority of ferrophosphorus is disposed of as waste slag, which not only occupies significant land but also causes harmful substances to enter the ground with rainwater, causing significant environmental pollution.

[0003] The resource utilization of ferrophosphorus is mainly applied in the preparation of new energy electrode materials and precursors, phosphate production and alloy smelting industries. The preparation of ferrophosphate precursor materials through ferrophosphorus is a hot topic in the resource utilization of ferrophosphorus. Common preparation methods can be divided into three categories: electrolysis, microwave digestion and precipitation. The ferrophosphate prepared by electrolysis has good crystallinity and a simple process, but this method greatly wastes a large amount of phosphorus in ferrophosphorus, and has the characteristics of high energy consumption and low yield. The microwave digestion method cannot be expanded due to its high equipment requirements. As a process with relatively mature technology development, the precipitation method has the advantages of simple process, fast flow, low cost, and controllable product morphology and particle size. However, this method will produce a large amount of harmful waste liquid during the reproduction process, which makes its production face huge environmental pressure. In the chemical industry, ferrophosphorus can also be used as a raw material for the production of disodium hydrogen phosphate and trisodium phosphate, but the presence of multiple impurities in ferrophosphorus greatly limits its wide application. In addition, ferrophosphorus was first used in steel and alloy smelting. For example, in some special steels, the addition of phosphorus gives the steel good toughness during the rolling process and avoids surface cracks.

[0004] At present, there are some literatures on the comprehensive utilization of ferrophosphorus resources, such as:

[0005] Patent application CN107792840B discloses a method for preparing ferric phosphate from ferric phosphorus, a byproduct of industrial yellow phosphorus production. This method involves oxidatively leaching the ferric phosphorus with an acidic potassium chlorate solution at 80-95°C for 6-8 hours to produce an aqueous solution containing iron and phosphate. The separated aqueous solution is purified to remove impurities, and the pH is adjusted to neutral with an alkaline solution to obtain a solid precipitate. The solid precipitate is slurried with water and the pH is adjusted to 1-2 with a phosphoric acid solution to obtain a solid precipitate. This solid precipitate is then washed, dried, and calcined to obtain the ferric phosphate. The resulting solution is evaporated, concentrated, cooled, and crystallized to obtain the sodium chloride product. This patent application demonstrates that the wet process in the first oxidative leaching step involves high temperatures and a long processing time. This wet process also generates a large amount of hazardous wastewater, making subsequent treatment difficult and costly, and placing significant environmental pressures. Furthermore, the entire recovery process requires a series of steps, including leaching, impurity removal, evaporation, concentration, and cooling crystallization. This results in a loss of target components and an increase in unwanted byproducts during the production process. This also increases energy consumption and places high demands on the equipment for corrosion and oxidation resistance.

[0006] 2. Patent application CN117735501A discloses a method for preparing ferric phosphate using ferrophosphorus slag, a by-product of yellow phosphorus production. The method is mainly divided into the following five steps: (1) crushing treatment: the ferrophosphorus slag is added to a crusher for crushing and screening to obtain the desired material; (2) oxidative roasting: the desired material is added to a tubular furnace and air or oxygen is introduced for roasting to obtain slag and P2O5 furnace gas; (3) acid dissolution and precipitation treatment: the obtained slag is subjected to acid dissolution treatment to obtain a phosphorus and iron mixture, and the mixture is adjusted in pH with an alkaline solution to obtain FePO4·2H2O precipitate; (4) sintering treatment: the obtained product FePO4·2H2O is placed in a muffle furnace and dehydrated at a certain temperature to generate product FePO4; (5) spraying and stirring: the obtained P2O5 furnace gas is subjected to hot spraying and stirring treatment to obtain H3PO4, which can be returned to the acid dissolution step for recycling. It can be seen that the patent application does not completely recover phosphorus during the first oxidation roasting process; and a large amount of impurities will still exist during the acid dissolution and precipitation process, thereby reducing product quality; and this method requires two steps of oxidation roasting and sintering, which greatly increases energy consumption and costs.

[0007] 3. Patent application CN115535980A discloses a method for preparing disodium hydrogen phosphate and ferric hydroxide from ferrophosphorus, a byproduct of yellow phosphorus. The method comprises: leaching the ferrophosphorus, a byproduct of yellow phosphorus, with nitric acid, filtering and separating the residue and filtrate, adding an alkaline reagent dropwise to the filtrate until the pH reaches 3.5 to 4.5, allowing the filtrate to stand at 30°C to 80°C for 30 to 60 minutes, and filtering, concentrating, and crystallizing to obtain disodium hydrogen phosphate. This patent application demonstrates that the use of nitric acid to leach the ferrophosphorus makes production equipment demanding. Adjusting the pH for precipitation cannot avoid the removal of a large amount of impurities. Furthermore, the entire process generates a large amount of acidic waste liquid, which poses a significant environmental hazard.

[0008] Therefore, how to effectively utilize ferrophosphorus as a whole through simple and efficient methods, while simplifying the recycling process and greatly reducing energy consumption, has become a key issue in the efficient recycling of ferrophosphorus resources. Summary of the Invention

[0009] In order to solve the above technical problems existing in the prior art, the present application provides a method for recovering ferrophosphide, a by-product of yellow phosphorus produced by an electric furnace process, comprising the following steps:

[0010] A method for recovering ferrophosphorus, a by-product of yellow phosphorus produced by an electric furnace process, comprises the following steps:

[0011] (1) Mixing phosphate rock with ferrophosphorus, additives and a small amount of water, and pressing them into short cylindrical pellets;

[0012] (2) sending the short cylindrical pellets from step (1) into a vertical quenching furnace for high-temperature oxidation roasting;

[0013] (3) The sample after constant temperature roasting in step (2) is subjected to high temperature sampling and air cooling to obtain high-grade roasted phosphate ore pellets.

[0014] Furthermore, the additive is silicon dioxide.

[0015] Furthermore, in step (1), phosphate rock, ferrophosphorus and additives are mixed according to the following weight ratio: 100 parts of phosphate rock, 5-8 parts of ferrophosphorus, and 45-50 parts of additives.

[0016] Furthermore, the pressing into short cylindrical pellets is performed by first mixing the phosphate rock, ferrophosphorus, additives and water evenly, and then feeding the mixture into a mold with a diameter of 20 to 30.01 mm for block forming.

[0017] Furthermore, the pressure of pressing into short cylinder is 8-12MPa

[0018] Furthermore, in the step (1), the phosphate rock, ferrophosphorus and additives are all powders with a particle size of 80 to 120 mesh.

[0019] Furthermore, in step (2), before the short cylindrical pellets are sent to the vertical quenching for high-temperature oxidation roasting, the formed short cylindrical pellets are first sent to a drying oven for drying until their moisture content is 0. Furthermore, the drying temperature is 90-110° C. and the drying time is 8-15 hours.

[0020] Furthermore, the high-temperature oxidation roasting in step (2) is carried out under the following conditions: controlling the reaction temperature to 1150-1320° C. in an air atmosphere and roasting at a constant temperature for 18-25 minutes.

[0021] Furthermore, the sample cooling method adopts a high-temperature sampling air cooling method.

[0022] Compared with the existing technology, the technical effects created by this application are embodied in:

[0023] 1. This application uses a high-temperature oxidation roasting method to oxidatively roast the phosphate rock and ferrophosphorus composition, and adds silicon dioxide to adjust the alkalinity of the roasted raw materials to 1. During the roasting process, ferrophosphorus will undergo oxidative decomposition at high temperature to produce Fe2O3 and P2O5. The entire decomposition process will release a large amount of heat to effectively supplement part of the energy required for the entire roasting process, thereby reducing the roasting temperature and energy consumption. Figure 2 As shown, the heat released by the sintered pellets is 35% of that released by carbon at the same added amount. The decomposed P2O5 acts as a supplemental phosphorus source, increasing the phosphorus content of the sintered pellets and helping to reduce the energy consumption required for subsequent yellow phosphorus production. Furthermore, the ferrophosphorus melts before decomposing during the calcination process, and its volume expands slightly. This results in improved bonding, higher strength, and increased porosity in the calcined pellets, resulting in pellets that are more suitable for electric furnace yellow phosphorus production.

[0024] 2. In order to solve the above-mentioned defects, the present application mixes phosphate rock with ferrophosphorus and additives, presses them into short columns, and then sends them into a vertical quenching furnace for high-temperature oxidation roasting to obtain pellets. During the entire treatment process, due to the heat released by oxidation and decomposition of ferrophosphorus, the oxidation roasting temperature can be appropriately lowered. Ferrophosphorus provides a phosphorus source to improve the grade of phosphate rock pellets, thereby realizing the resource utilization efficiency of ferrophosphorus, reducing energy consumption, and eliminating the emission of three wastes.

[0025] 3. The present application reasonably controls the amount of ferrophosphorus added, so that the addition of ferrophosphorus can provide sufficient heat while ensuring that the phosphorus component can be completely integrated into the phosphate ore pellets, thereby not only reducing energy consumption in the phosphate ore pelletizing process, but also effectively improving the grade of the phosphate ore pellets.

[0026] 4. The present application combines the addition amount of ferrophosphorus with the reasonable control of the temperature, so that the ferrophosphorus can not only provide part of the energy required for roasting under the condition of complete decomposition and replenishment of the phosphorus source, but also ensure that the high temperature avoids the increase in the melting amount of the sample and the instability of the pellet structure. At the same time, this method can achieve efficient resource recycling of all ferrophosphorus components through simple sintering and pelletizing.

[0027] 5. The present application uses a mixed roasting process of ferrophosphorus and phosphate rock to make pellets. During the high-temperature oxidation process of ferrophosphorus, not only a phosphorus source is provided for the entire pellet, but also a large amount of heat is released due to oxidative decomposition, which allows the roasting temperature to be appropriately lowered during the roasting process, thereby reducing the energy consumption of the entire process and achieving efficient comprehensive recycling of ferrophosphorus. At the same time, this method has the advantages of simple process flow, easy operation, and no production of three wastes, which makes it have obvious advantages in the comprehensive utilization and recycling of ferrophosphorus resources. Under the condition that the ferrophosphorus addition amount is 10%, not only the recovery rates of iron and phosphorus in ferrophosphorus are higher than 99%, but also the problems of high cost, high pollution, low utilization rate, large output of waste and by-products, etc. that appear in the process of preparing ferric phosphate using ferrophosphorus are effectively solved, so that it can achieve the purpose of green and efficient recycling of ferrophosphorus resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a flowchart of this application.

[0029] Figure 2 This is a comparison chart of the heat release of carbon and ferrophosphorus at the same addition amount. DETAILED DESCRIPTION

[0030] The technical solution of the present application is further defined below in conjunction with specific implementation methods, but the scope of protection required is not limited to the description.

[0031] The present invention uses phosphate rock produced by a factory in Guizhou and ferrophosphorus produced during the production process as raw materials, and analyzes their chemical compositions to obtain the mass fractions of the components shown in Tables 1 and 2 below:

[0032] Table 1 Chemical composition and content of phosphate rock

[0033] Element CaO <![CDATA[P2O5]]> <![CDATA[SiO2]]> <![CDATA[Al2O3]]> MgO <![CDATA[Fe2O3]]> F <![CDATA[Na2O]]> Content (wt%) 49.23 29.35 5.26 1.02 1.73 2.31 1.42 0.11

[0034] Table 2 Chemical composition and content of ferrophosphorus

[0035] Element Fe P Si Ti Ca V Mn Cr Content (wt%) 75.07 22.41 0.23 0.74 0.21 0.32 0.21 0.17

[0036] Table 3 Main raw materials and additive amounts of Experimental Examples 1 to 5

[0037] Phosphate rock / g Ferrophosphorus / g Silicon dioxide / g Example 1 100 2 47.5 Example 2 100 4 47.5 Example 3 100 6 47.5 Example 4 100 8 47.5 Example 5 100 10 47.5

[0038] Example 1

[0039] A method for recovering yellow phosphorus by-product (ferrophosphorus) produced by an electric furnace process comprises the following steps:

[0040] (1) mixing phosphate rock with ferrophosphorus, an additive, and a small amount of water, and pressing the mixture into a short cylinder; the phosphate rock, ferrophosphorus, and the additive are powders having a particle size of 80 to 100 mesh;

[0041] (2) sending the short cylindrical pellets of step (1) into a vertical quenching furnace for high-temperature oxidation roasting; the oxidation roasting conditions are: controlling the reaction temperature to 1150-1300° C. in an air atmosphere, and constant temperature roasting for 19-21 minutes;

[0042] (3) The sample after constant temperature roasting for a certain period of time in step (2) is subjected to high temperature sampling and air cooling to obtain high-grade roasted phosphate ore pellets.

[0043] Furthermore, in step (1), the additive is silicon dioxide, and the phosphate rock, ferrophosphorus, and additive are mixed in the following weight ratio: 100 parts of phosphate rock, 2 parts of ferrophosphorus, and 43-48 parts of additive. The pressing into short columns is performed by first mixing the phosphate rock, ferrophosphorus, additive, and a small amount of water evenly, and then placing the mixture into a mold with a diameter of 20-30.01 mm for compacting. The pressure for pressing into short columns is 8-10 MPa. In step (2), before the column is placed in a vertical quenching furnace for high-temperature oxidation roasting, the formed column is first placed in a drying oven for drying until its moisture content is 0. The drying temperature is 85-100°C and the drying time is 12-15 hours.

[0044] Example 2

[0045] A method for recovering yellow phosphorus by-product (ferrophosphorus) produced by an electric furnace process comprises the following steps:

[0046] (1) mixing phosphate rock with ferrophosphorus, an additive, and a small amount of water, and pressing the mixture into a short cylinder; the particle size of the phosphate rock, ferrophosphorus, and the additive is a powder of 90 to 110 mesh;

[0047] (2) feeding the short cylindrical pellets obtained in step (1) into a vertical quenching furnace for high-temperature oxidation roasting; the oxidation roasting conditions are: controlling the reaction temperature to 1160-1310° C. in an air atmosphere, and roasting at a constant temperature for 19-22 minutes;

[0048] (3) The sample after constant temperature roasting for a certain period of time in step (2) is subjected to high temperature sampling and air cooling to obtain high-grade roasted phosphate ore pellets.

[0049] Furthermore, in step (1), the additive is silicon dioxide, and the phosphate rock, ferrophosphorus and additive are mixed in the following weight ratio: 100 parts of phosphate rock, 4 parts of ferrophosphorus, and 44-48 parts of additive. The pressing into short columns is to first mix the phosphate rock, ferrophosphorus, additive and a small amount of water evenly, and then put them into a mold with a diameter of 20-30.01 mm to form blocks. The pressure for pressing into short columns is 8.5-11.5 MPa. In step (2), before the column is sent to a vertical quenching for high-temperature oxidation roasting, the formed column is first sent to a drying oven for drying until its moisture content is 0. The drying temperature is 95-105°C and the drying time is 9-13 hours.

[0050] Example 3

[0051] A method for recovering yellow phosphorus by-product (ferrophosphorus) produced by an electric furnace process comprises the following steps:

[0052] (1) mixing phosphate rock with ferrophosphorus, an additive, and a small amount of water, and pressing the mixture into a short cylinder; the phosphate rock, ferrophosphorus, and the additive are powders having a particle size of 100 to 150 mesh;

[0053] (2) feeding the short cylindrical pellets obtained in step (1) into a vertical quenching furnace for high-temperature oxidation roasting; the oxidation roasting conditions are: controlling the reaction temperature to 1170-1300° C. in an air atmosphere, and roasting at a constant temperature for 17-21 minutes;

[0054] (3) The sample after constant temperature roasting for a certain period of time in step (2) is subjected to high temperature sampling and air cooling to obtain high-grade roasted phosphate ore pellets.

[0055] Furthermore, in step (1), the additive is silicon dioxide, and the phosphate rock, ferrophosphorus and additive are mixed in the following weight ratio: 100 parts of phosphate rock, 6 parts of ferrophosphorus, and 46-48 parts of additive. The pressing into short columns is performed by first mixing the phosphate rock, ferrophosphorus, additive and a small amount of water evenly, and then placing them into a mold with a diameter of 20-30.01 mm for block forming. The pressure for pressing into short columns is 9-11 MPa. In step (2), before the column is sent to a vertical quenching furnace for high-temperature oxidation roasting, the formed column is first sent to a drying oven for drying until its moisture content is 0. The drying temperature is 80-105°C and the drying time is 10-12 hours.

[0056] Example 4

[0057] A method for recovering yellow phosphorus by-product (ferrophosphorus) produced by an electric furnace process comprises the following steps:

[0058] (1) mixing phosphate rock with ferrophosphorus, an additive, and a small amount of water, and pressing the mixture into a short cylinder; the phosphate rock, ferrophosphorus, and the additive are powders having a particle size of 80 to 100 mesh;

[0059] (2) feeding the short cylindrical pellets obtained in step (1) into a vertical quenching furnace for high-temperature oxidation roasting; the oxidation roasting conditions are: controlling the reaction temperature to 1170-1300° C. in an air atmosphere, and roasting at a constant temperature for 19-21 minutes;

[0060] (3) The sample after constant temperature roasting for a certain period of time in step (2) is subjected to high temperature sampling and air cooling to obtain high-grade roasted phosphate ore pellets.

[0061] Furthermore, in step (1), the additive is silicon dioxide, and the phosphate rock, ferrophosphorus, and additive are mixed in the following weight ratio: 100 parts of phosphate rock, 8 parts of ferrophosphorus, and 45-51 parts of additive. The pressing into short columns is performed by first mixing the phosphate rock, ferrophosphorus, additive, and a small amount of water evenly, and then placing the mixture into a mold with a diameter of 20-30.01 mm for compacting. The pressure for pressing into short columns is 9.5-10.5 MPa. In step (2), before the column is placed in a vertical quenching furnace for high-temperature oxidation roasting, the formed column is first placed in a drying oven for drying until its moisture content is 0. The drying temperature is 100-120° C. and the drying time is 8-10 hours.

[0062] Example 5

[0063] A method for recovering yellow phosphorus by-product (ferrophosphorus) produced by an electric furnace process comprises the following steps:

[0064] (1) mixing phosphate rock with ferrophosphorus, additives and a small amount of water, and pressing the mixture into a short cylinder; the particle size of the phosphate rock, ferrophosphorus and additives is 80-120 mesh powder;

[0065] (2) feeding the short cylindrical pellets obtained in step (1) into a vertical quenching furnace for high-temperature oxidation roasting; the oxidation roasting conditions are: controlling the reaction temperature to 1150-1320° C. in an air atmosphere, and roasting at a constant temperature for 18-25 minutes;

[0066] (3) The sample after constant temperature roasting for a certain period of time in step (2) is subjected to high temperature sampling and air cooling to obtain high-grade roasted phosphate ore pellets.

[0067] Furthermore, in step (1), the additive is silicon dioxide, and the phosphate rock, ferrophosphorus, and additive are mixed in the following weight ratio: 100 parts of phosphate rock, 10 parts of ferrophosphorus, and 47-48 parts of additive. The pressing into short columns is performed by first mixing the phosphate rock, ferrophosphorus, additive, and a small amount of water evenly, and then placing them into a mold with a diameter of 20-30.01 mm for block forming. The pressure for pressing into short columns is 8-12 MPa. In step (2), before the column is sent to a vertical quenching furnace for high-temperature oxidation roasting, the formed column is first sent to a drying oven for drying until its moisture content is 0. The drying temperature is 90-110° C. and the drying time is 10-15 hours.

[0068] Comparative Example 1

[0069] The difference from Example 5 is that although the pressure during the calcination process is normal pressure, the atmosphere is argon, and other conditions remain unchanged.

[0070] Comparative Example 2

[0071] The difference from Example 5 is that the calcination temperature is controlled at 900° C. during the calcination process, and other conditions remain unchanged.

[0072] Comparative Example 3

[0073] Phosphorus and iron were recovered from the ferrophosphorus slag using a method combined with Example 1 and Example 4 of patent application CN118183651A (A method for recovering ferrophosphate from ferrophosphorus slag after lithium extraction, ferrophosphate materials and applications).

[0074] Comparative Example 4

[0075] Phosphorus and iron were recovered from the ferrophosphorus slag using the method of Example 1 of patent application CN118545689A (A method for recovering ferrophosphorus from lithium extraction tailings).

[0076] Comparative Example 5

[0077] Phosphorus and iron were recovered from the ferrophosphorus slag using the method of Example 3 of patent application CN118406880A (a method for recycling ferrophosphorus slag after lithium extraction).

[0078] The methods of Examples 1 to 5 of the present application and Comparative Examples 1 to 5 were used to respectively conduct tests on the recovery of by-product ferrophosphorus and phosphorus. X-ray fluorescence spectrometry and inductively coupled plasma mass spectrometry were used to test and analyze the changes in the total amount of iron and phosphorus in the samples before and after treatment with the examples. The test results of the recovery rates of iron and phosphorus after treating 100 g of yellow phosphorus slag with different methods are shown in Table 4 below.

[0079] Table 4 Experimental results of treating 100g ferrophosphorus slag with different methods

[0080] Group Iron recovery rate Phosphorus recovery rate Group Iron recovery rate Phosphorus recovery rate Example 1 99.4％ 98.8％ Comparative Example 1 85.8％ 82.3％ Example 2 99.1％ 98.5％ Comparative Example 2 86.7％ 82.5％ Example 3 99.3％ 96.7％ Comparative Example 3 97.6％ 97.3％ Example 4 99.2％ 98.2％ Comparative Example 4 89.0％ 83.3％ Example 5 99.5％ 99.1％ Comparative Example 5 92.4％ 96.3％

[0081] As can be seen from the experimental data in Table 4, during the comprehensive recycling of ferrophosphorus slag by the present method, the recovery rates of iron and phosphorus in the sample show a trend of first decreasing and then increasing as the amount of ferrophosphorus increases. This is because at a lower addition amount, ferrophosphorus can be well oxidized and decomposed; when the amount of ferrophosphorus added is appropriately increased, some ferrophosphorus will have a reduced recovery rate due to insufficient energy required; but as the amount of ferrophosphorus continues to increase, the ferrophosphorus releases heat to compensate for the energy required for oxidation, resulting in a gradual increase in the recovery rates of iron and phosphorus. Compared with the method of recovering ferrophosphorus to prepare battery precursor materials, this method has a higher recovery rate and almost completely recovers the ferrophosphorus.

[0082] In summary, the present application is to roast and pelletize ferrophosphorus by mixing ferrophosphorus with phosphate rock. During the high-temperature oxidation process of ferrophosphorus, not only a phosphorus source is provided for the entire pellet, but also a large amount of heat is released due to oxidative decomposition, which makes it possible to appropriately reduce the roasting temperature during the roasting process, thereby reducing the energy consumption of the entire process and realizing efficient comprehensive recycling of ferrophosphorus. At the same time, the method has the advantages of simple process flow, easy operation, and no production of three wastes, which makes it have obvious advantages in the comprehensive utilization and recycling of ferrophosphorus resources. Under the condition that the ferrophosphorus addition amount is 10%, not only the recovery rates of iron and phosphorus in ferrophosphorus are higher than 99%, but also the problems of high cost, high pollution, low utilization rate, large output of waste and by-products, etc. that appear in the process of preparing ferric phosphate using ferrophosphorus are effectively solved, so that it can realize the purpose of green and efficient recycling of ferrophosphorus resources.

[0083] Finally, it should be noted that the above embodiments are merely representative examples of this application. Obviously, the technical solutions of this application are not limited to the above embodiments and are subject to numerous variations. All variations that can be directly derived or conceived by a person of ordinary skill in the art from the disclosure of this application should be considered within the scope of protection of this application.

Claims

1. A method for recovering ferrophosphorus as a by-product of yellow phosphorus produced by an electric furnace process, characterized in that: The steps include: (1) mixing phosphate rock with ferrophosphorus, an additive of silicon dioxide, and a small amount of water, and pressing the mixture into short cylindrical pellets; wherein the phosphate rock, ferrophosphorus, and the additive are mixed in the following weight ratio: 100 parts of phosphate rock, 5-8 parts of ferrophosphorus, and 45-50 parts of the additive; (2) sending the short cylindrical pellets from step (1) into a vertical quenching furnace for high-temperature oxidation roasting; the high-temperature oxidation roasting is carried out under the following conditions: controlling the reaction temperature to 1150-1320° C. in an air atmosphere and roasting at a constant temperature for 18-25 minutes; (3) The sample after constant temperature roasting in step (2) is subjected to high temperature sampling and air cooling to obtain high-grade roasted phosphate ore pellets.

2. The method for recovering ferrophosphorus as a by-product of electric furnace yellow phosphorus according to claim 1, wherein: The pressing into short cylindrical pellets is performed by first mixing the phosphate rock, ferrophosphorus, additives and water evenly, and then feeding the mixture into a mold with a diameter of 20 to 30.01 mm for block forming.

3. The method for recovering ferrophosphorus as a by-product of electric furnace yellow phosphorus according to claim 2, wherein: The pressure for pressing into the short column is 8-12 MPa.

4. The method for recovering ferrophosphorus as a by-product of electric furnace yellow phosphorus according to claim 1, wherein: In the step (1), the phosphate rock, ferrophosphorus and additives are all powders with a particle size of 80 to 120 meshes.

5. The method for recovering ferrophosphorus as a by-product of electric furnace yellow phosphorus according to claim 1, characterized in that: In the step (2), before the short column pellets are sent to the vertical quenching for high-temperature oxidation roasting, the formed short column pellets are first sent to a drying oven for drying until the moisture content is 0.

6. The method for recovering ferrophosphorus as a by-product of electric furnace yellow phosphorus according to claim 5, characterized in that: The drying temperature is 90-110° C. and the drying time is 8-15 hours.

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