A method for producing ferrophosphorus powder by recycling industrial waste and its preparation process

Abstract

The present invention provides a method for producing ferrophosphorus powder by recycling industrial waste and a preparation process thereof, and belongs to the technical field of metal material production. The present invention uses industrial waste ferrophosphorus slag and waste acid solution, and adds tetrapropylammonium bromide, a pore expander, a dispersant, etc. to modify the ferrophosphorus slag to achieve recycling of industrial waste; at the same time, the modified ferrophosphorus slag is subjected to high-temperature treatment together with high-phosphorus iron ore, calcium-containing substances, sulfides, etc., to achieve the removal of impurity elements such as silicon and copper while preparing ferrophosphorus powder.

Description

Technical Field

[0001] The invention relates to a smelting method of ferrophosphorus powder, belonging to the technical field of metal material production, and in particular to a method of producing ferrophosphorus powder by recycling industrial waste and a preparation process thereof. Background Art

[0002] Ferrophosphorus slag is an important metallurgical by-product. It is a mineral rich in phosphorus and iron. Its main components are FeP and Fe2P, and it contains impurities such as silicon and copper. The iron content is generally more than 50%, and the phosphorus content is more than 20%. If the ferrophosphorus slag is piled up for a long time without being treated, it will not only cause a waste of ferrophosphorus resources, but also cause secondary pollution to the environment. In addition, the impurity elements in the ferrophosphorus slag are difficult to separate, and the presence of impurities will affect the purity, making it difficult to meet the use environment.

[0003] The patent "A ferrophosphorus and its preparation method" (application number: CN201310332335.9) discloses a method for preparing ferrophosphorus. The patent obtains ferrophosphorus powder by smelting ferrophosphorus slag, high-phosphorus iron ore and dolomite in a smelting furnace. The preparation method is simple in process and the utilization rate of ferrophosphorus slag is as high as over 98%, so that the waste ferrophosphorus slag can be recycled, thereby improving the utilization rate of ferrophosphorus slag; however, the patent does not deal with the impurity elements in the ferrophosphorus powder, and the purity of the product needs to be improved.

[0004] Therefore, how to use industrial waste for recycling to produce ferrophosphorus powder, and effectively remove impurity elements in ferrophosphorus powder on the basis of using industrial waste, and improve the purity of ferrophosphorus powder, has become a direction that needs to be focused on. Summary of the invention

[0005] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a method for producing ferrophosphorus powder by recycling industrial waste and a preparation process thereof. The present invention uses industrial waste ferrophosphorus slag and waste acid solution, and adds tetrapropylammonium bromide, a pore expander, a dispersant, etc. to modify the ferrophosphorus slag to achieve the recycling of industrial waste; at the same time, the modified ferrophosphorus slag is treated with high-phosphorus iron ore, calcium-containing substances, sulfides, etc. at high temperature to remove impurity elements such as silicon and copper while preparing ferrophosphorus powder, and obtains desiliconized and copper-free modified ferrophosphorus powder after crushing.

[0006] To achieve this object, the present invention adopts the following technical solutions:

[0007] A preparation process for producing ferrophosphorus powder by recycling industrial waste comprises the following steps:

[0008] Step S1: by weight, 100 to 200 parts of ferrophosphorus slag and acid solution are mixed, and the suspension A is obtained by stirring, wherein the solid content of the suspension A after mixing is 40 to 50%; the pH value of the suspension A is adjusted to 7-9, tetrapropylammonium bromide and a pore-enlarging agent are added dropwise for hydrothermal reaction to obtain a suspension B; the pH value of the suspension B is adjusted to neutral, a dispersant is added for wet ball milling to obtain a slurry; and the slurry is spray-dried to obtain modified ferrophosphorus slag.

[0009] Step S2: by weight, 80-90 parts of modified ferrophosphorus slag, 10-20 parts of high-phosphorus iron ore, 5-10 parts of calcium-containing substances and 2-5 parts of sulfides are ball-milled and mixed on a ball mill to obtain a mixture A, which is then tableted on a tablet press at a pressure of 4-8 MPa; the tableted mixture A is placed in a graphite crucible in a vacuum furnace for a first stage of high-temperature treatment and a second stage of high-temperature treatment, and the slag is removed after cooling to room temperature, and the desiliconized and copper-modified ferrophosphorus powder is obtained after crushing.

[0010] The present invention first performs modification treatment on ferrophosphorus slag, and obtains modified ferrophosphorus slag with a high specific surface area through the action of a pore expanding agent; then performs a first stage high-temperature treatment and a second stage high-temperature treatment on the modified ferrophosphorus slag, and removes different impurity elements through the staged temperature treatment, thereby realizing the recycling of industrial waste to produce ferrophosphorus powder.

[0011] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the objectives and beneficial effects of the present invention can be better achieved and realized.

[0012] As a preferred technical solution of the present invention, the acid solution in step S1 includes a first acid solution and a second acid solution, the first acid solution is HW34 waste acid solution, the second acid solution is concentrated sulfuric acid, and the mass ratio of the first acid solution to the second acid solution is 1:(0.5~2), for example, it can be 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, 1:1.6, 1:1.7, 1:1.8, 1:1.9 or 1:2, etc.

[0013] In the present invention, both ferrophosphorus slag and waste acid liquid are industrial wastes, and the ferrophosphorus slag can be dissolved in an acidic environment of concentrated sulfuric acid or concentrated nitric acid. By adding industrial waste acid liquid into the dissolving acid liquid, the ferrophosphorus slag and the waste acid liquid can be recycled while ensuring that the ferrophosphorus slag can be dissolved, thereby effectively achieving green environmental protection. The present invention controls the mass ratio of the first acid liquid to the second acid liquid within a specific range, thereby ensuring the dissolution efficiency of the ferrophosphorus slag in an acidic environment and also achieving the recycling of the waste acid liquid.

[0014] Preferably, the weight proportion of tetrapropylammonium bromide in step S1 is 5 to 10 parts, for example, 5 parts, 5.5 parts, 6 parts, 7 parts, 7.5 parts, 8 parts, 8.5 parts, 9 parts, 9.5 parts or 10 parts.

[0015] As a preferred technical solution of the present invention, the pore expanding agent in step S1 is selected from any one of hexamethyleneimine, trimethylbenzene, and sesbania powder, or a combination of at least two of them; preferably, the weight proportion of the pore expanding agent in step S1 is 5 to 10 parts, for example, it can be 5 parts, 6 parts, 7 parts, 8 parts, 8 parts, 9 parts or 10 parts, etc.

[0016] Preferably, the dispersant in step S1 is selected from any one of polyvinyl pyrrolidone, sodium polyacrylate, and sodium hexametaphosphate, or a combination of at least two thereof; the weight proportion of the dispersant is 4 to 8 parts, for example, 4 parts, 4.5 parts, 5 parts, 5.5 parts, 6 parts, 6.5 parts, 7 parts, 7.5 parts or 8 parts, etc.

[0017] In the present invention, ferrophosphorus slag as industrial waste contains a certain amount of silicon element. The ferrophosphorus slag is modified by adding tetrapropylammonium bromide and a pore expanding agent, and in combination with the silicon element in the industrial waste. The specific surface area of ​​the modified ferrophosphorus slag obtained by spray drying is increased, which is beneficial to the subsequent further removal of impurity elements. At the same time, the high specific surface area is beneficial to expanding the application scenarios of ferrophosphorus powder.

[0018] As a preferred technical solution of the present invention, the calcium-containing substance in step S2 is selected from any one of calcium oxide, calcium carbonate, and dolomite, or a combination of at least two thereof; the calcium-containing substance is further selected from dolomite. The weight proportion of the calcium-containing substance is 5 to 10 parts, for example, 5 parts, 5.5 parts, 6 parts, 7 parts, 7.5 parts, 8 parts, 8.5 parts, 9 parts, 9.5 parts, or 10 parts.

[0019] In the present invention, dolomite is one of the raw materials for preparing ferrophosphorus powder, and dolomite will decompose into carbon dioxide and calcium oxide when heated to 700-900°C, wherein calcium oxide can activate silicon in ferrophosphorus powder into calcium silicate under high temperature conditions, and silicon element will enter the slag phase in the form of Ca2SiO4 and Ca3SiO5 and be separated from ferrophosphorus, thereby realizing desiliconization treatment.

[0020] As a preferred technical solution of the present invention, the sulfide in step S2 is selected from any one of sodium sulfide, ferrous sulfide, and stannous sulfide, or a combination of at least two of them; the sulfide is further selected as stannous sulfide; the weight proportion of the sulfide is 2 to 5 parts, for example, it can be 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts or 5 parts, etc.

[0021] In the present invention, stannous sulfide can react with copper in ferrophosphorus slag under the condition of 700-750° C. to form cuprous sulfide which enters the slag phase and is separated from ferrophosphorus, thereby achieving the purpose of copper removal.

[0022] As a preferred technical solution of the present invention, the first high-temperature treatment temperature of the graphite crucible in the vacuum furnace in step S2 is 700-750°C, for example, it can be 700°C, 710°C, 720°C, 730°C, 740°C or 750°C; the treatment time is 30-40min, for example, it can be 30min, 31min, 32min, 33min, 34min, 35min, 36min, 37min, 38min, 39min or 40min.

[0023] The second high temperature treatment temperature in step S2 is 1300-1350°C, for example, it can be 1300°C, 1310°C, 1320°C, 1330°C, 1340°C or 1350°C; the pressure is 10-40Pa, for example, it can be 10Pa, 15Pa, 20Pa, 25Pa, 30Pa, 35Pa or 40Pa; the constant temperature time is 50-60min, for example, it can be 50min, 51min, 52min, 53min, 54min, 55min, 56min, 57min, 58min, 59min or 60min.

[0024] In the present invention, modified ferrophosphorus slag, high-phosphorus iron ore, dolomite and stannous sulfide are mixed and subjected to high-temperature treatment at both ends, wherein during the first stage of high-temperature treatment, stannous sulfide is ensured to react with copper in the ferrophosphorus slag to achieve copper removal treatment; and part of the dolomite can be decomposed into carbon dioxide and calcium oxide by constant temperature treatment at the temperature to ensure the subsequent reaction of calcium oxide with silicon element. At the same time, the second stage of high-temperature treatment can activate the calcium oxide generated by the previous dolomite decomposition and the silicon in the ferrophosphorus powder into calcium silicate, realize the separation of silicon element and ferrophosphorus, and improve the fluidity of the tin element generated after the copper removal treatment, and promote its entry into the slag phase.

[0025] According to another aspect of the present invention, the present invention also provides a ferrophosphorus powder prepared according to the above preparation process.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] (1) The present invention uses ferrophosphorus slag and waste acid solution in combination, controls the mass ratio of the first acid solution to the second acid solution in the acid solution within a specific range, ensures that the ferrophosphorus slag can be dissolved in the acid solution, and realizes the recycling of industrial waste ferrophosphorus slag and waste acid solution, thereby achieving the purpose of green environmental protection.

[0028] (2) The present invention utilizes the silicon element contained in the ferrophosphorus slag, in combination with tetrapropylammonium bromide, a pore-enlarging agent and a dispersant, to modify the ferrophosphorus slag to obtain modified ferrophosphorus slag with a high specific surface area, and the subsequent removal of impurity elements is promoted by the high specific surface area.

[0029] (3) The present invention prepares ferrophosphorus powder by using modified ferrophosphorus slag, high-phosphorus iron ore, dolomite and stannous sulfide, removes copper and silicon elements by high-temperature treatment at both ends, avoids multiple heating and cooling treatments for different impurity elements, and realizes efficient removal of impurities in ferrophosphorus powder. DETAILED DESCRIPTION

[0030] For the convenience of understanding the present invention, the present invention lists the following embodiments. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0031] Some of the component sources are as follows:

[0032] The first acid liquid: HW34 waste acid liquid;

[0033] Second acid: concentrated sulfuric acid CAS No. 7664-93-9;

[0034] Tetrapropylammonium bromide CAS No. 1941-30-6:

[0035] Pore ​​expanding agent: trimethylbenzene CAS No. 25551-13-7;

[0036] Dispersant: Sodium hexametaphosphate CAS No. 10124-56-8, sodium polyacrylate CAS No. 9003-04-7;

[0037] High phosphorus iron ore: purchased from Wuhan Iron and Steel Co., Ltd.;

[0038] Calcium-containing substances: dolomite CAS No. 16389-88-1;

[0039] Sulfide: Stannous sulfide CAS No. 1314-95-0.

[0040] Example 1

[0041] This embodiment provides a preparation process for producing ferrophosphorus powder by recycling industrial waste, comprising the following steps:

[0042] Step S1: In parts by weight, 100 parts of ferrophosphorus slag are mixed with acid solution (the mass ratio of the first acid solution to the second acid solution in the acid solution is 1:0.5), and the suspension A is obtained by stirring. After mixing, the solid content of the suspension A is 40%; the pH value of the suspension A is adjusted to 7, and 5 parts of tetrapropylammonium bromide and 10 parts of trimethylbenzene as a pore-expanding agent are added for hydrothermal reaction to prepare a suspension B; the pH value of the suspension B is adjusted to neutral, and 4 parts of sodium hexametaphosphate as a dispersant are added for wet ball milling to prepare a slurry; the slurry is spray-dried to obtain modified ferrophosphorus slag.

[0043] Step S2: In parts by weight, 80 parts of modified ferrophosphorus slag, 10 parts of high-phosphorus iron ore, 10 parts of dolomite and 2 parts of stannous sulfide are ball-milled and mixed on a ball mill to obtain a mixture A, and then the mixture is pressed on a tablet press at a pressure of 8MPa; the pressed mixture A is placed in a graphite crucible in a vacuum furnace for a first high-temperature treatment and a second high-temperature treatment, the first high-temperature treatment temperature is 700°C, the time is 40min, the second high-temperature treatment temperature is 1350°C, the pressure is 10Pa, and the constant temperature time is 50min; after cooling to room temperature, the slag is removed, and the desiliconized and copper-modified ferrophosphorus powder is obtained after crushing.

[0044] Example 2

[0045] This embodiment provides a preparation process for producing ferrophosphorus powder by recycling industrial waste, comprising the following steps:

[0046] Step S1: In parts by weight, 200 parts of ferrophosphorus slag are mixed with acid solution (the mass ratio of the first acid solution to the second acid solution in the acid solution is 1:2), and the suspension A is obtained by stirring. After mixing, the solid content of the suspension A is 50%; the pH value of the suspension A is adjusted to 9, and 10 parts of tetrapropylammonium bromide and 5 parts of trimethylbenzene as a pore-expanding agent are added dropwise for hydrothermal reaction to prepare a suspension B; the pH value of the suspension B is adjusted to neutral, and 8 parts of sodium hexametaphosphate as a dispersant are added for wet ball milling to prepare a slurry; the slurry is spray-dried to obtain modified ferrophosphorus slag.

[0047] Step S2: In parts by weight, 90 parts of modified ferrophosphorus slag, 20 parts of high-phosphorus iron ore, 5 parts of dolomite and 5 parts of stannous sulfide are ball-milled and mixed on a ball mill to obtain a mixture A, which is then pressed on a tablet press at a pressure of 4 MPa; the pressed mixture A is placed in a graphite crucible in a vacuum furnace for a first high-temperature treatment and a second high-temperature treatment, the first high-temperature treatment temperature is 750°C, the time is 30 minutes, the second high-temperature treatment temperature is 1300°C, the pressure is 40 Pa, and the constant temperature time is 60 minutes; after cooling to room temperature, the slag is removed, and the desiliconized and copper-modified ferrophosphorus powder is obtained after crushing.

[0048] Example 3

[0049] This embodiment provides a preparation process for producing ferrophosphorus powder by recycling industrial waste, comprising the following steps:

[0050] Step S1: In parts by weight, 150 parts of ferrophosphorus slag are mixed with acid solution (the mass ratio of the first acid solution to the second acid solution in the acid solution is 1:1), and stirred to obtain suspension A, wherein the solid content of suspension A after mixing is 45%; the pH value of suspension A is adjusted to 8, and 8 parts of tetrapropylammonium bromide and 7 parts of pore-enlarging agent trimethylbenzene are added dropwise for hydrothermal reaction to prepare suspension B; the pH value of suspension B is adjusted to neutral, and 6 parts of dispersant sodium polyacrylate are added for wet ball milling to prepare slurry; the slurry is spray-dried to obtain modified ferrophosphorus slag.

[0051] Step S2: In parts by weight, 85 parts of modified ferrophosphorus slag, 15 parts of high-phosphorus iron ore, 8 parts of dolomite and 4 parts of stannous sulfide are ball-milled and mixed on a ball mill to obtain a mixture A, which is then pressed on a tablet press at a pressure of 6 MPa; the pressed mixture A is placed in a graphite crucible in a vacuum furnace for a first high-temperature treatment and a second high-temperature treatment, the first high-temperature treatment temperature is 730°C, the time is 34 minutes, the second high-temperature treatment temperature is 1340°C, the pressure is 30 Pa, and the constant temperature time is 55 minutes; after cooling to room temperature, the slag is removed, and the desiliconized and copper-modified ferrophosphorus powder is obtained after crushing.

[0052] Example 4

[0053] This embodiment provides a preparation process for producing ferrophosphorus powder by recycling industrial waste. The only difference from Example 1 is that the mass ratio of the first acid solution to the second acid solution in the acid solution is changed from 1:0.5 to 1:0.2, and other conditions are the same as those in Example 1.

[0054] Example 5

[0055] This embodiment provides a preparation process for producing ferrophosphorus powder by recycling industrial waste. The only difference from Example 1 is that the pore-expanding agent trimethylbenzene is changed from 10 parts to 2 parts, and other conditions are the same as those of Example 1.

[0056] Comparative Example 1

[0057] This comparative example provides a preparation process of ferrophosphorus powder, comprising the following steps:

[0058] In parts by weight, 80 parts of ferrophosphorus slag and 10 parts of high-phosphorus iron ore are added to a graphite crucible in a vacuum furnace for smelting. The smelting process adopts a conventional smelting process, wherein the smelting temperature is 1350° C., the smelting time is 35 minutes, and ferrophosphorus powder is obtained after crushing.

[0059] Comparative Example 2

[0060] This comparative example provides a preparation process of ferrophosphorus powder, comprising the following steps:

[0061] 80 parts of ferrophosphorus slag, 10 parts of high-phosphorus iron ore, 10 parts of dolomite and 2 parts of stannous sulfide are added into a smelting furnace for smelting. The smelting process adopts a conventional smelting process, wherein the smelting temperature is 1350°C, the smelting time is 35 minutes, and ferrophosphorus powder is obtained after crushing.

[0062] The ferrophosphorus powder provided in the above embodiment and comparative example was tested for silicon and copper content, and the specific testing method is as follows:

[0063] The test methods for silicon and copper content refer to "GB / T 6730.87-2023 Determination of total iron and other multi-element content in iron ore - Wavelength dispersive X-ray fluorescence spectrometry".

[0064] The above performance test data is shown in Table 1:

[0065] Table 1

[0066] It should be noted that the above embodiments illustrate rather than limit the present invention, and that those skilled in the art may design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference symbol between brackets shall not be construed as limiting the claims. The word "comprising" does not exclude the presence of elements or operations not listed in the claims.

Claims

1. A preparation process for producing ferrophosphorus powder by recycling industrial waste, characterized in that: The preparation process comprises the following steps: Step S1: by weight, 100-200 parts of ferrophosphorus slag and acid solution are mixed, and stirred to obtain suspension A, wherein the solid content of suspension A after mixing is 40-50%; the pH value of suspension A is adjusted to 7-9, tetrapropylammonium bromide and a pore-enlarging agent are added dropwise for hydrothermal reaction to obtain suspension B; the pH value of suspension B is adjusted to neutral, a dispersant is added for wet ball milling to obtain a slurry; the slurry is spray-dried to obtain modified ferrophosphorus slag; Step S2: by weight, 80-90 parts of modified ferrophosphorus slag, 10-20 parts of high-phosphorus iron ore, 5-10 parts of calcium-containing substances and 2-5 parts of sulfide are ball-milled and mixed on a ball mill to obtain a mixture A, and then tabletted on a tablet press; the tabletted mixture A is placed in a graphite crucible in a vacuum furnace for a first stage of high-temperature treatment and a second stage of high-temperature treatment, and the slag is removed after cooling to room temperature, and the desiliconized and copper-modified ferrophosphorus powder is obtained after crushing; The first stage of high temperature treatment of the graphite crucible in the vacuum furnace in step S2 is performed at a temperature of 700-750° C. for 30-40 min. In step S2, the second stage high temperature treatment temperature is 1300-1350°C, the pressure is 10-40Pa, and the constant temperature time is 50-60min.

2. The process for producing ferrophosphorus powder by recycling industrial waste according to claim 1, characterized in that: The acid solution in step S1 includes a first acid solution and a second acid solution, the first acid solution is HW34 waste acid solution, the second acid solution is concentrated sulfuric acid, and the mass ratio of the first acid solution to the second acid solution is 1:(0.5~2).

3. The preparation process for producing ferrophosphorus powder by recycling industrial waste according to claim 1, characterized in that: The pore expanding agent in step S1 is selected from any one of hexamethyleneimine, trimethylbenzene, and sesbania powder, or a combination of at least two of them.

4. The preparation process for producing ferrophosphorus powder by recycling industrial waste according to claim 1, characterized in that: In step S1, the dispersant is selected from any one of polyvinyl pyrrolidone, sodium polyacrylate, sodium hexametaphosphate, or a combination of at least two thereof.

5. The preparation process for producing ferrophosphorus powder by recycling industrial waste according to claim 1, characterized in that: The calcium-containing substance in step S2 is selected from any one of calcium oxide, calcium carbonate, and dolomite, or a combination of at least two of them.

6. The preparation process for producing ferrophosphorus powder by recycling industrial waste according to claim 1, characterized in that: The sulfide in step S2 is selected from any one of sodium sulfide, ferrous sulfide, and stannous sulfide, or a combination of at least two of them.

7. The process for producing ferrophosphorus powder by recycling industrial waste according to claim 1, characterized in that: The pressure of the tablet press in step S2 is 4-8 MPa.

8. A ferrophosphorus powder prepared by the process as claimed in any one of claims 1 to 7.

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