Method for recovering electric furnace process yellow phosphorus byproduct ferrophosphorus

Abstract

The invention relates to ferrophosphorus resource recycling, in particular to a method for recycling an electric furnace process yellow phosphorus by-product ferrophosphorus. The phosphorite and ferrophosphorus composition is subjected to oxidizing roasting through a high-temperature oxidizing roasting method, and silicon dioxide is added to adjust the alkalinity of roasting raw materials to be 1. In the roasting process, ferrophosphorus can be oxidized and decomposed at high temperature to generate Fe2O3 and P2O5, and a large amount of heat can be released in the whole decomposition process to effectively supplement part of energy required by the whole roasting process, so that the roasting temperature is reduced, and the energy consumption is reduced. And meanwhile, decomposed P2O5 is used as a supplementary phosphorus source, so that the phosphorus content of the sintered pellets is increased, and the energy consumption required by the next step of yellow phosphorus production is reduced. And in the roasting process, ferrophosphorus is melted before being decomposed, and the volume is slightly expanded, so that the roasted pellets are better in adhesive property, higher in strength and increased in voids, and the pellets which are more beneficial to yellow phosphorus production by an electric furnace method are obtained.

Description

Technical Field

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

[0002] Ferrophosphorus slag is a waste material of the phosphorus industry. Due to the different production raw materials and process conditions, the composition is relatively complex. It contains a large amount of iron and phosphorus, and the total content of the two exceeds 80%. Usually the iron content is 50% to 75%, and the phosphorus content is 18% to 30%. In addition, it also contains a small amount of silicon, mainly in the form of SiO2. In the process of producing yellow phosphorus by the electric furnace method, for every ton of yellow phosphorus produced, 0.1 to 0.2 tons of ferrophosphorus by-products are generated. Except for a small part of ferrophosphorus used as raw materials for the production of steel metallurgy and phosphates, most of it is treated as waste slag, which not only occupies a large amount of land, but also the harmful substances in it will enter the ground with rainwater, thus causing great pollution to the environment.

[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 by 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 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 requirements for equipment. As a process with relatively mature technology development, the precipitation method has the advantages of simple process, fast process, low cost, and controllable product morphology and particle size. However, a large amount of harmful waste liquid will be generated during the reproduction process of this method, 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] 1. Patent application CN107792840B discloses a method for preparing ferric phosphate using ferric phosphorus, a byproduct of industrial yellow phosphorus production. The method uses potassium chlorate acid solution to oxidize and leach ferric phosphorus for 6 to 8 hours at 80 to 95°C to obtain an aqueous solution containing iron and phosphate. The aqueous solution separated by leaching is purified to remove impurity elements, 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 reversed to 1 to 2 with a phosphoric acid solution to obtain a solid precipitate. After washing, drying and calcination, ferric phosphate is obtained; the solution obtained by separation and precipitation is evaporated and concentrated, cooled and crystallized, and a sodium chloride product is obtained. It can be seen that the wet treatment temperature in the first step of oxidation leaching in this patent application is high, the treatment time is long, and the wet treatment will produce a large amount of harmful waste liquid, which is difficult and costly to handle later, and has great environmental pressure. At the same time, the entire recovery process needs to go through a series of steps such as leaching, impurity removal, evaporation concentration, cooling and crystallization, so it will lead to the loss of target components in the production process, increase excess by-products, increase energy consumption, and have high requirements for equipment corrosion resistance and oxidation.

[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: adding the ferrophosphorus slag into a crusher for crushing and screening to obtain the desired material; (2) oxidative roasting: adding the desired material into a tubular furnace, and introducing air or oxygen for roasting to obtain slag and P2O5 furnace gas; (3) acid dissolution and precipitation treatment: subjecting the obtained slag to acid dissolution treatment to obtain a phosphorus and iron mixed solution, and adjusting the pH of the mixed solution with an alkaline solution to obtain FePO4·2H2O precipitate; (4) sintering treatment: placing the obtained product FePO4·2H2O in a muffle furnace and dehydrating it at a certain temperature to generate product FePO4; (5) spraying and stirring: subjecting the obtained P2O5 furnace gas 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 did not completely recover phosphorus during the first oxidation roasting process; and a large amount of impurities were still present during the acid dissolution and precipitation process, thereby reducing the product quality; and the method required two steps of oxidation roasting and sintering, which greatly increased 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 ferrophosphorus, a byproduct of yellow phosphorus, with nitric acid, filtering and separating to obtain filter residue and filtrate, adding alkaline reagent to the filtrate until the pH is 3.5 to 4.5, standing at 30°C to 80°C for 30 to 60 minutes, filtering, concentrating and crystallizing to obtain disodium hydrogen phosphate. It can be seen that the patent application uses nitric acid to leach ferrophosphorus, which makes the production equipment requirements higher. It is impossible to avoid the removal of a large number of impurities by adjusting the pH precipitation. At the same time, the whole process will also produce a large amount of acidic waste liquid, which is very harmful to the environment.

[0008] Therefore, how to effectively utilize ferrophosphorus as a whole through simple and efficient methods, while simplifying the recycling process and reducing energy consumption as much as possible, 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 ferrophosphorus, a byproduct of yellow phosphorus produced by an electric furnace process, comprising the following steps:

[0010] A method for recovering ferrophosphorus as a byproduct 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 of 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 to first mix the phosphate rock, ferrophosphorus, additives and water evenly, and then put them into a mold with a diameter of 20 to 30.01 mm for block forming.

[0017] Furthermore, the pressure for pressing into a short column is 8-12 MPa.

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

[0019] Furthermore, in 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. 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: the reaction temperature is controlled to be 1150-1320° C. in an air atmosphere, and the roasting is carried out 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 prior art, the technical effects created by this application are embodied in:

[0023] 1. This application uses a high-temperature oxidation roasting method to oxidize and roast the phosphate ore and ferrophosphorus combination, and adds silicon dioxide to adjust the basicity of the roasting raw materials to 1. During the roasting process, ferrophosphorus will undergo oxidation 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 reducing energy consumption. Figure 2 As shown, the heat release is 35% of the heat release of carbon compared with the same amount of carbon added. At the same time, the decomposed P2O5 serves as a supplementary phosphorus source, so that the phosphorus content of the pellets after sintering can be increased, which helps to reduce the energy consumption required for the next step of yellow phosphorus production. In addition, the ferrophosphorus will melt before decomposition 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 method.

[0024] 2. In order to solve the above defects, the present application mixes phosphate ore 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 the oxidation decomposition of ferrophosphorus, the oxidation roasting temperature can be appropriately reduced. The ferrophosphorus provides a phosphorus source to improve the grade of phosphate ore pellets, thereby realizing the efficient resource utilization 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 reasonably controls the temperature in combination with the amount of ferrophosphorus added, 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. This application uses mixed roasting of ferrophosphorus and phosphate ore to make pellets. The high-temperature oxidation process of ferrophosphorus not only provides a phosphorus source for the entire pellet, but also releases a large amount of heat due to oxidation and decomposition, so that the roasting temperature can be appropriately reduced during the roasting process, thereby reducing the energy consumption of the entire process and achieving efficient and comprehensive recycling of ferrophosphorus. At the same time, this method has the advantages of simple process flow, easy operation, and no generation of three wastes, which makes it have obvious advantages in the comprehensive utilization and recycling of ferrophosphorus resources. Under the condition that the addition amount of ferrophosphorus 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 in the process of preparing iron 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 limited below in conjunction with specific implementation methods, but the scope of protection required is not limited to the description.

[0031] The present application example uses phosphate rock produced by a factory in Guizhou and ferrophosphorus produced in the production process as raw materials, and analyzes its chemical composition, and obtains the mass fractions of its components as 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 additives used in 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 byproduct (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 with a particle size of 80 to 100 meshes;

[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 roasting at a constant temperature 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 to first mix the phosphate rock, ferrophosphorus, additive and a small amount of water evenly, and then send them into a mold with a diameter of 20-30.01 mm to form blocks. The pressure of pressing into short columns is 8-10 MPa. In step (2), before sending the columnar body into a vertical quenching for high-temperature oxidation roasting, the formed columnar body is first sent to a drying oven for drying until its moisture content is 0. The drying temperature is 85-100°C and the time is 12-15 hours.

[0044] Example 2

[0045] A method for recovering yellow phosphorus byproduct (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 meshes;

[0047] (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 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 send 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 sending the columnar body into a vertical quenching for high-temperature oxidation roasting, the formed columnar body is first sent to a drying oven for drying until its moisture content is 0. The drying temperature is 95-105°C and the time is 9-13 hours.

[0050] Example 3

[0051] A method for recovering yellow phosphorus byproduct (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 column; the phosphate rock, ferrophosphorus and the additive have a particle size of 100 to 150 mesh powder;

[0053] (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 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 to first mix the phosphate rock, ferrophosphorus, additive and a small amount of water evenly, and then send them into a mold with a diameter of 20-30.01 mm to form blocks. The pressure for pressing into short columns is 9-11 MPa. In step (2), before sending the columnar body into a vertical quenching for high-temperature oxidation roasting, the formed columnar body is first sent to a drying oven for drying until its moisture content is 0. The drying temperature is 80-105°C and the time is 10-12 hours.

[0056] Example 4

[0057] A method for recovering yellow phosphorus byproduct (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 with a particle size of 80 to 100 meshes;

[0059] (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 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 to first mix the phosphate rock, ferrophosphorus, additive and a small amount of water evenly, and then send them into a mold with a diameter of 20-30.01 mm to form blocks. The pressure of pressing into short columns is 9.5-10.5 MPa. In step (2), before sending the columnar body into a vertical quenching for high-temperature oxidation roasting, the formed columnar body is first sent to a drying oven for drying until its moisture content is 0. The drying temperature is 100-120°C and the time is 8-10 hours.

[0062] Example 5

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

[0064] (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 have a particle size of 80 to 120 mesh powder;

[0065] (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 1150-1320° 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 to first mix the phosphate rock, ferrophosphorus, additive and a small amount of water evenly, and then send them into a mold with a diameter of 20-30.01 mm to form blocks. The pressure of pressing into short columns is 8-12 MPa. In step (2), before sending the columnar body into a vertical quenching for high-temperature oxidation roasting, the formed columnar body is first sent to a drying oven for drying until its moisture content is 0. The drying temperature is 90-110°C and the 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 during the calcination process, the calcination temperature is controlled to be 900° C., and other conditions remain unchanged.

[0072] Comparative Example 3

[0073] Phosphorus and iron were recovered from the ferrophosphorus slag by using the method of the combination of Example 1 and Example 4 of patent application CN118183651A (a method for recovering iron phosphate from ferrophosphorus slag after lithium extraction, iron phosphate material and application).

[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 in lithium extraction tailings).

[0076] Comparative Example 5

[0077] Phosphorus and iron are 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 carry out tests on the recovery of by-product ferrophosphorus and phosphorus. X-ray fluorescence spectrometer and inductively coupled plasma mass spectrometer were used to test and analyze the changes in the total amount of iron and phosphorus in the samples before and after the treatment of the embodiments. The test results of the recovery rates of iron and phosphorus after treating 100g of yellow phosphorus slag by different methods were recorded as 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] It can be seen from the experimental data in Table 4 that in the process of comprehensive recycling of ferrophosphorus slag by the method of this application, as the amount of ferrophosphorus increases, the recovery rate of iron and phosphorus in the sample shows a trend of first decreasing and then increasing. This is because at a lower addition amount, ferrophosphorus can be well oxidized and decomposed; when the amount of ferrophosphorus is appropriately increased, part of the ferrophosphorus will reduce the recovery rate due to insufficient energy required; but after continuously increasing the amount of ferrophosphorus, the ferrophosphorus releases heat to make up for the energy required for oxidation, thus causing the recovery rate of iron and phosphorus to gradually increase. Compared with the method of recovering ferrophosphorus to prepare battery precursor materials, this method has a higher recovery rate and almost fully recovers ferrophosphorus.

[0082] In summary, the present application uses mixed roasting of ferrophosphorus and phosphate ore to make pellets. The high-temperature oxidation process of ferrophosphorus not only provides a phosphorus source for the entire pellet, but also releases a large amount of heat due to oxidation and decomposition, so that the roasting temperature can be appropriately reduced during the roasting process, thereby reducing the energy consumption of the entire process and realizing the efficient and comprehensive recycling of ferrophosphorus. At the same time, the method has the advantages of simple process flow, easy operation, and no generation of three wastes, which makes it have obvious advantages in the comprehensive utilization and recycling of ferrophosphorus resources. Under the condition that the addition amount of ferrophosphorus 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 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.

[0083] Finally, it should be pointed out that the above embodiments are only representative examples of the present application. Obviously, the technical solution of the present application is not limited to the above embodiments, and there may be many variations. All variations that can be directly derived or associated with the contents disclosed in the present application by a person of ordinary skill in the art should be considered as the protection scope of the present 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, additives and a small amount of water, and pressing them into short cylindrical pellets; (2) sending the short cylindrical pellets of step (1) into a vertical quenching furnace for high temperature oxidation roasting; (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 produced as a byproduct of electric furnace yellow phosphorus according to claim 1, characterized in that: The additive is silicon dioxide.

3. The method for recovering ferrophosphorus produced as a byproduct of electric furnace yellow phosphorus according to claim 1, characterized in that: In the 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.

4. The method for recovering ferrophosphorus produced as a byproduct of electric furnace yellow phosphorus according to claim 1, characterized in that: The pressing into short columnar pellets is to first mix the phosphate rock, ferrophosphorus, additives and water evenly, and then put them into a mold with a diameter of 20 to 30.01 mm for block forming.

5. The method for recovering ferrophosphorus produced as a byproduct of yellow phosphorus produced by an electric furnace process according to claim 4, characterized in that: The pressure for pressing into the short column is 8-12 MPa.

6. The method for recovering ferrophosphorus produced as a byproduct of yellow phosphorus produced by an electric furnace process according to claim 1, characterized in that: In the step (1), the phosphate rock, ferrophosphorus and additives are all powders with a particle size of 80 to 120 meshes.

7. The method for recovering ferrophosphorus produced as a byproduct of yellow phosphorus produced by an electric furnace process 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.

8. The method for recovering ferrophosphorus produced as a byproduct of yellow phosphorus produced by an electric furnace process according to claim 7, characterized in that: The drying temperature is 90-110° C. and the drying time is 8-15 hours.

9. The method for recovering ferrophosphorus produced as a byproduct of yellow phosphorus produced by an electric furnace process according to claim 1, characterized in that: The high temperature oxidation roasting in step (2) is carried out under the following conditions: the reaction temperature is controlled to be 1150-1320° C. in an air atmosphere, and the roasting is carried out at a constant temperature for 18-25 minutes.

10. The method for recovering ferrophosphorus produced as a byproduct of yellow phosphorus produced by an electric furnace process according to claim 1, characterized in that: The sample cooling method adopts a high-temperature sampling air cooling method.

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