Method for reducing Fe content by crushing carbonized slag through vertical mill

Abstract

The invention relates to the field of carbide slag production, and provides a method for reducing Fe content by crushing carbide slag through a vertical mill, which comprises the following steps: in the process of crushing the carbide slag through the vertical mill, after raw materials enter a vertical mill system, the iron content in a vertical mill finished product collected by a dust collection system is lower than that in the raw materials by adjusting the process parameters of the vertical mill. According to the method, the purpose of reducing the iron content is achieved by adjusting the technological parameters of the vertical mill, and the technical problems that in the prior art, equipment modification is needed, and additional procedures and input cost are needed are solved.

Description

Technical Field

[0001] The invention relates to the field of carbide slag production, and in particular to a method for crushing carbide slag with a vertical mill to reduce Fe content. Background Art

[0002] The titanium extraction process from blast furnace slag independently developed by Panzhihua Iron and Steel is a unique process technology in the world. The content of titanium dioxide (TiO2) in blast furnace slag is as high as 21% to 25%. According to statistics, the total amount of TiO2 entering Panzhihua Iron and Steel blast furnace slag is more than 700,000 tons each year. Since 2008, Panzhihua Iron and Steel Group has fully opened up the high-temperature carbonization-low-temperature chlorination production process for titanium extraction from blast furnace slag through the development of intermediate test production lines, and completed the technical research and development of each link, especially the optimization of process technology indicators has been further improved. This includes the process of converting titanium (Ti) in titanium-containing blast furnace slag into titanium carbide (TiC) through electric furnaces and vertical mill systems.

[0003] CN 108940466 B discloses an iron removal device in a vertical mill, comprising a vertical mill housing, a rotating shaft, an electromagnetic device and a discharge device; the left end of the rotating shaft extends into the interior of the vertical mill housing, and the right end is connected to a driving mechanism; the electromagnetic device is arranged obliquely above the vertical mill grinding disc, and comprises an electromagnet and a wear-resistant plate, the wear-resistant plate is arranged on the outer side of the electromagnet, the inner side of the electromagnet is fixedly connected to the rotating shaft through a supporting rib plate, and the adsorption surface of the wear-resistant plate is a concave curved surface; the discharge device is an external discharge chute, the feed end of the external discharge chute is in the vertical mill housing and corresponds to the discharge end of the wear-resistant plate, and the discharge end of the external discharge chute is outside the vertical mill housing. This prior art realizes iron removal operation on the grinding disc, effectively preventing magnetic iron raw materials from being circulated and ground in the vertical mill system, but adds a set of iron removal devices to collect and process the iron in the material.

[0004] CN 117303366 A discloses a low-Fe TiC-containing slag and a preparation method thereof, the method comprising the following steps: S1, using blast furnace slag containing TiO2 as raw material for electric furnace smelting; S2, water quenching after electric furnace smelting to obtain water-quenched slag; S3, crushing the water-quenched slag with rollers, and magnetically separating the material after roller crushing to obtain primary iron-containing particles and tailings; S4, sending the tailings into a vertical mill system to obtain secondary iron-containing particles and finished slag, and returning the obtained secondary iron-containing particles to the electric furnace for smelting. The prior art controls appropriate process flow and process parameters, and adopts a primary wet magnetic separation after water quenching and rough crushing to remove large Fe inclusions and a secondary Fe removal technology after vertical milling under appropriate magnetic field strength to prepare a low-Fe TiC-containing slag, the iron content in the finished slag is ≤1.5%, and the comprehensive loss rate of TiC in the process is ≤3%. However, the prior art wet magnetic separation tailings are sent into the vertical mill system, the system return material amount is controlled, and a magnetic field is applied to the return material surface for secondary iron removal.

[0005] CN 109174318 A discloses a method for removing iron from titanium carbide slag. The method comprises the following steps: using a vertical mill process to crush titanium carbide slag, controlling the amount of returned materials to be 5% to 45% of the amount of feed materials during the vertical mill crushing process, subjecting the obtained returned materials to magnetic separation for iron removal, sending the returned materials after magnetic separation for iron removal into a feeding system for further crushing, and sending the crushed fine powder to a collection system through a vertical mill discharge port to obtain qualified titanium carbide slag. In the vertical mill process, the grinding roller pressure of the vertical mill is controlled at 3 to 7 MPa, the inlet and outlet pressure difference of the vertical mill in the vertical mill process is 1.2 kPa to 2.1 kPa, and the magnetic field strength on the surface of the returned materials in the magnetic separation step is 400 Gs to 800 Gs. This prior art reduces the Fe content in the titanium carbide-containing slag while ensuring a small loss of TiC in the titanium carbide-containing slag powder by controlling appropriate vertical mill process parameters and using the technology and means of returning material to remove iron by magnetic separation. The loss of TiC in the titanium carbide-containing slag powder is less than 2.5%, and the Fe content is reduced to less than 3%, meeting the requirements of the subsequent low-temperature chlorination process for the Fe content in the slag. However, this prior art uses returning material to remove iron by magnetic separation to reduce the iron content.

[0006] Based on this, there is room for improvement in reducing the iron content by adjusting the vertical mill process parameters of the vertical mill system during the vertical mill crushing of carburized slag. Summary of the invention

[0007] In view of this, the object of the present invention is to provide a method for crushing carburized slag by a vertical mill to reduce the Fe content, so as to solve the technical problem that the prior art requires equipment modification, additional processes and investment costs.

[0008] In order to achieve the above object, the technical solution provided by the present invention is: A method for reducing Fe content by crushing carbide slag with a vertical mill comprises: in the process of crushing carbide slag with a vertical mill, after the raw material enters the vertical mill system, adjusting the vertical mill process parameters so that the iron content in the vertical mill finished product collected by the dust collection system is lower than the iron content in the raw material.

[0009] In some embodiments, the raw material is titanium-containing blast furnace slag that has been smelted in an electric furnace and water quenched.

[0010] In some embodiments, the method for crushing carburized slag with a vertical mill to reduce Fe content comprises the following steps: Step 1, selecting raw materials and feeding the raw materials into the vertical mill of the vertical mill system; Step 2: During the grinding process of the vertical mill, the parameters of the separator and the dust collecting fan are adjusted during the continuous production process, and the finished products of the vertical mill are collected; Step 3: during the grinding process of the vertical mill, after the continuous production for the first time, the material inside the vertical mill is discharged from the vertical mill system; Step 4: Repeat steps 2 and 3; Step five, obtaining the finished vertical mill product.

[0011] In some embodiments, step 2 also includes adjusting the system air volume during continuous production.

[0012] In some embodiments, in step 2, adjusting the separator parameters and dust collecting fan parameters during the continuous production process includes: adjusting the frequency of the separator to prevent fine particles with a high iron content from carbonizing and passing through the separator while meeting the particle size requirements of the vertical mill finished product.

[0013] In some embodiments, in step 2, adjusting the separator parameters and dust collecting fan parameters during the continuous production process includes: adjusting the frequency of the dust collecting fan while meeting the particle size requirements of the vertical mill finished product, and matching the frequency of the dust collecting fan with the frequency of the separator.

[0014] In some embodiments, the frequency of the separator is 10-30 Hz, the frequency of the dust collecting fan is 40-50 Hz, and the system air volume is 60000-85000m 3 / h.

[0015] In some embodiments, in step three, discharging the material inside the vertical mill out of the vertical mill system after continuous production for a first time includes: lifting the grinding roller after continuous production for the first time, discharging the material inside the vertical mill to the outside of the vertical mill system for a second time, and then lowering the grinding roller.

[0016] In some embodiments, the first time is 3 to 4 hours, and the second time is 10 to 15 minutes.

[0017] In some embodiments, in step three, the mass percentage of iron in the material discharged out of the vertical mill system is less than or equal to 38%.

[0018] The beneficial effects of the present invention are: The method for reducing the Fe content by crushing carbide slag with a vertical mill of the present invention is applied to a vertical mill system, that is, in the process of crushing carbide slag with a vertical mill, the purpose of reducing the iron content is achieved by adjusting the process parameters of the vertical mill, thereby solving the technical problem that the prior art requires equipment modification, additional processes and investment costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 It is a schematic diagram of a method for reducing Fe content by crushing carburized slag with a vertical mill according to an embodiment of the present invention. DETAILED DESCRIPTION

[0021] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the embodiments of the present invention are further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0022] It should be noted that all expressions using "first" and "second" in the embodiments of the present invention are for distinguishing two non-identical entities with the same name or non-identical parameters. It can be seen that "first" and "second" are only for the convenience of expression and should not be understood as limitations on the embodiments of the present invention. The subsequent embodiments will not explain this one by one.

[0023] The method for reducing the Fe content by crushing carbide slag with a vertical mill provided by the present invention comprises: in the process of crushing carbide slag with a vertical mill, after the raw material enters the vertical mill system, adjusting the vertical mill process parameters so that the iron content in the vertical mill finished product collected by the dust collection system is lower than the iron content in the raw material.

[0024] In some embodiments, the raw material is titanium-containing blast furnace slag that is smelted in an electric furnace and water quenched, and the iron content in the material has a large correlation with the iron content in the raw material smelted in the electric furnace.

[0025] In some embodiments, the raw material is a material produced by Panzhihua Iron and Steel after smelting in an electric furnace and quenching in water, and the mass percentage of iron in the material is less than or equal to 5%. Table 1 shows the composition and mass percentage of the material produced by Panzhihua Iron and Steel after smelting in an electric furnace and quenching in water, that is, the composition and mass percentage of carbide slag.

[0026] Table 1 Composition and mass percentage of carburized slag

[0027] TFe refers to total iron, which is the sum of all iron elements, including iron in different forms and valence states, such as cementite, ferrous oxide, ferric oxide, ferric oxide, and metallic iron. m O n Refers to titanium oxides, including titanium monoxide, titanium dioxide, titanium trioxide, titanium pentoxide, and composite oxides formed in solid solution or with other metal oxides, such as calcium titanate.

[0028] The presence of iron in the raw materials corresponding to the titanium-containing blast furnace slag produced by Panzhihua Iron and Steel after electric furnace smelting and water quenching is different from the presence of iron in general blast furnace slag. The raw material phase analysis is: the perovskite phase in the blast furnace slag basically disappears, most of the titanium pyroxene is transformed into ordinary pyroxene, and the titanium element in the pre-furnace carbide slag mainly appears in the form of carbon oxide titanium or titanium carbide, and a small part is present in titanium pyroxene. The raw materials were analyzed by the mineral parameter automatic quantitative analysis system MLA, and the results are shown in Tables 2 and 3. Table 2 shows the mineral composition of the raw materials.

[0029] Table 2 Mineral composition of raw materials

[0030] Others are non-mineral items that cannot be detected by the mineral parameter automatic quantitative analysis system MLA, mainly including low counting rate, porosity, etc.

[0031] The iron element in the raw materials corresponding to the titanium-containing blast furnace slag produced by Panzhihua Iron and Steel after electric furnace smelting and water quenching still exists in the form of metallic iron. Among them, the metallic iron is mixed with trace elements such as vanadium, manganese, titanium, and silicon. The mass percentage of metallic iron in the raw materials is about 0.65%, and the particle size distribution range of metallic iron is 7.88-126.13μm. Table 3 shows the particle size distribution of metallic iron in the raw materials. The particle size distribution range of iron in general blast furnace slag is 7.88-75μm. The iron content in the raw materials corresponding to the titanium-containing blast furnace slag produced by Panzhihua Iron and Steel after electric furnace smelting and water quenching has obvious enrichment and growth, which has great advantages for the subsequent vertical mill deironing operation of the entire process.

[0032] Table 3 Particle size of metallic iron in raw materials

[0033] The raw materials corresponding to the materials of titanium-containing blast furnace slag produced by Panzhihua Iron and Steel after electric furnace smelting and water quenching were obtained by the method of crushing carburized slag by vertical mill to reduce Fe content of the present invention, and the finished vertical mill was analyzed by the mineral parameter automatic quantitative analysis system MLA, and the results are shown in Tables 4 and 5. Table 4 shows the mineral composition of the finished vertical mill.

[0034] Table 4 Mineral composition of finished vertical mill

[0035] Others are non-mineral items that cannot be detected by the mineral parameter automatic quantitative analysis system MLA, mainly including low counting rate, porosity, etc.

[0036] The morphology of the metal iron particles in the finished product of the vertical mill becomes round, but there is still a layer of titanium carbide or titanium oxycarbide around them. The particle size distribution range of the metal iron is 4.69~89.19μm. Table 5 shows the particle size of the metal iron in the finished product of the vertical mill. Its particle size is significantly smaller than that of the pre-furnace slag and water-quenched slag.

[0037] Table 5 Particle size of metallic iron in the finished product of vertical mill

[0038] like Figure 1 As shown, the method for reducing Fe content by crushing carburized slag with a vertical mill of the present invention comprises the following steps: Step 1, selecting raw materials and feeding the raw materials into the vertical mill of the vertical mill system; Step 2: During the grinding process of the vertical mill, the parameters of the separator and the dust collecting fan are adjusted during the continuous production process, and the finished products of the vertical mill are collected; Step 3: during the grinding process of the vertical mill, after the continuous production for the first time, the material inside the vertical mill is discharged from the vertical mill system; Step 4: Repeat steps 2 and 3; Step five, obtaining the finished vertical mill product.

[0039] Compared with the prior art, the method of reducing the Fe content by crushing carbide slag with a vertical mill of the present invention adjusts the separator parameters and the dust collection fan parameters during the continuous production process of the vertical mill and regularly discharges the internal materials of the vertical mill out of the vertical mill system, thereby achieving the purpose of reducing the iron content by adjusting the vertical mill process parameters, thereby solving the technical problem that the prior art requires equipment modification, additional processes and investment costs.

[0040] In some embodiments, in step 2, adjusting the separator parameters and dust collecting fan parameters during the continuous production process includes: adjusting the frequency of the separator to prevent fine particles with a high iron content from carbonizing and passing through the separator while meeting the particle size requirements of the finished product.

[0041] In some embodiments, the frequency of the separator is 10-30 Hz.

[0042] In some embodiments, in step two, adjusting the separator parameters and dust collection fan parameters during the continuous production process includes: adjusting the frequency of the dust collection fan while meeting the particle size requirements of the finished product, and matching the frequency of the dust collection fan with the frequency of the separator, thereby preventing fine particles with a higher iron content from carbonizing and passing through the separator.

[0043] In some embodiments, the frequency of the dust collecting fan is 40-50 Hz.

[0044] In some embodiments, in step 2, the system air volume is adjusted during the continuous production process, and the system air volume is 60000~85000m 3 / h.

[0045] In some embodiments, in step three, discharging the material inside the vertical mill out of the vertical mill system after continuous production for a first time includes: lifting the grinding roller after continuous production for the first time, discharging the material inside the vertical mill to the outside of the vertical mill system for a second time, and then lowering the grinding roller.

[0046] In some embodiments, the first time is 3 to 4 hours, and the second time is 10 to 15 minutes.

[0047] In some embodiments, the material inside the vertical mill includes raw materials that are being ground inside the vertical mill or raw materials that are too coarse to be ground.

[0048] In some embodiments, in step three, the mass percentage of iron in the material discharged out of the vertical mill system is less than or equal to 38%.

[0049] In some embodiments, in step three, the materials discharged to the outside of the vertical mill system include the fine particles with high iron content that are blocked by carbonization and pass through the separator in step two.

[0050] In some embodiments, in step three, the load of the separator and the dust collecting fan is reduced and they are not in working state.

[0051] The specific implementation of the method for reducing Fe content by crushing carburized slag with a vertical mill of the present invention is as follows: In the HLM1900 vertical mill system for high temperature carbonization of titanium from blast furnace slag of Panzhihua Iron and Steel, in the production practice of the equipment No. 17-L-028 vertical mill, the raw materials are the titanium-containing blast furnace slag produced by Panzhihua Iron and Steel after electric furnace smelting and water quenching. The following 7 raw materials are selected, and the typical components and mass percentages of the typical components in the 7 raw materials are shown in Table 6. The mass percentage of TFe in the 7 raw materials is 1.58% to 3.97%, with an average of 2.23%.

[0052] Table 6 Raw materials and their typical components and mass percentages

[0053] TTi refers to total titanium, including the sum of various forms of titanium, such as titanium in all titanium-containing substances such as titanium alone and compounds. Total C refers to the sum of various forms of carbon, including free carbon and compounded carbon. Low C refers to free carbon, that is, the sum of carbon that has not formed compounds with other elements.

[0054] The seven kinds of raw materials shown in Table 6 are continuously fed into the equipment No. 17-L-028 vertical mill in sequence. During the grinding process of the equipment No. 17-L-028 vertical mill, the frequency of the separator is controlled to 18-25Hz, the frequency of the dust collecting fan is controlled to 45-48Hz, and the system air volume is controlled to 75000-83000m 3 / h, preventing fine particles with high iron content from carbonizing and passing through the separator to collect the finished products of the vertical mill.

[0055] During the grinding process of the equipment No. 17-L-028 vertical mill, the grinding roller was lifted after 4 hours of continuous production for 12 minutes, and the materials that were being ground or the coarse particles that could not be ground inside the equipment No. 17-L-028 vertical mill were concentrated and discharged to the outside of the blast furnace slag titanium high temperature carbonization HLM1900 vertical mill system to reduce the iron content, and then the grinding roller was lowered, and the equipment No. 17-L-028 vertical mill continued to produce continuously. During the lifting of the grinding roller, the load of the separator and the dust collection fan was reduced and they were not in working state. The materials discharged from the blast furnace slag titanium high temperature carbonization HLM1900 vertical mill system were randomly selected three times for chemical analysis. The mass percentage of TFe in the materials was 17.07% to 35.81%, with an average of 24.46%. The typical components and mass percentages of the typical components in the materials discharged from the blast furnace slag titanium high temperature carbonization HLM1900 vertical mill system are shown in Table 7.

[0056] Table 7 Typical composition and mass percentage of the discharged materials

[0057] The typical components and mass percentages of the vertical mill products corresponding to the seven raw materials are shown in Table 8. The TFe content in the vertical mill products is 1.12%-1.87%, with an average of 1.32%, which is 0.91% lower than the TFe content in the raw materials, and the reduction rate reaches 40.81%.

[0058] Table 8 Typical components and mass percentage of vertical mill finished products and vertical mill finished products

[0059] The method of reducing the Fe content by crushing carburized slag with a vertical mill of the present invention is a method of reducing the iron content in the material after electric furnace smelting and water quenching of titanium-containing blast furnace slag as raw material by adjusting the process parameters of the vertical mill. The method of the present invention is mainly applied to the vertical mill system, that is, in the process of crushing carburized slag with a vertical mill, a series of technical measures are taken to reduce the iron content in the finished product, thereby improving the chlorination rate of the next process (low-temperature chlorination), reducing the iron content in the tailings of the low-temperature chlorination process, and thus improving the yield of the entire low-temperature chlorination process. The method of the present invention can be promoted and applied in Panzhihua Iron and Steel and domestic peers, especially in the high-temperature carbonization process of extracting titanium from titanium-containing blast furnace slag. In addition, the method of the present invention is analyzed and summarized from the aspect of process operation, forming a method with certain operation technology and capable of reducing electrode consumption.

[0060] So far, various embodiments of the present invention have been described in detail. In order to avoid obscuring the concept of the present invention, some details known in the art are not described. Based on the above description, those skilled in the art can fully understand how to implement the technical solution disclosed here.

[0061] Although some specific embodiments of the present invention have been described in detail by way of examples, it should be understood by those skilled in the art that the above examples are only for illustration and not for limiting the scope of the present invention. It should be understood by those skilled in the art that the above embodiments may be modified or some technical features may be replaced by equivalents without departing from the scope and spirit of the present invention.

Claims

1. A method for reducing Fe content by crushing carburized slag with a vertical mill, characterized in that: include: In the process of crushing carburized slag with a vertical mill, after the raw materials enter the vertical mill system, the vertical mill process parameters are adjusted so that the iron content in the vertical mill finished product collected by the dust collection system is lower than the iron content in the raw materials.

2. The method for reducing Fe content by crushing carbonized slag with a vertical mill according to claim 1, characterized in that: The raw material is titanium-containing blast furnace slag smelted in an electric furnace and water quenched.

3. The method for reducing Fe content by crushing carbonized slag by vertical mill according to claim 1, characterized in that: The following steps are involved: Step 1, selecting the raw material and putting the raw material into the vertical mill of the vertical mill system; Step 2, during the grinding process of the vertical mill, adjusting the parameters of the separator and the dust collecting fan in the continuous production process, and collecting the finished products of the vertical mill; Step 3, during the grinding process of the vertical mill, after continuous production for a first time, the material inside the vertical mill is discharged out of the vertical mill system; Step 4, repeating step 2 and step 3; Step five, obtaining the finished vertical mill.

4. The method for reducing Fe content by crushing carbonized slag by vertical mill according to claim 3, characterized in that: In the step 2, it also includes adjusting the system air volume during the continuous production process.

5. The method for reducing Fe content by crushing carbonized slag with a vertical mill according to claim 4, characterized in that: In the step 2, adjusting the separator parameters and dust collecting fan parameters during the continuous production process includes: adjusting the frequency of the separator to prevent fine particles with a high iron content from carbonizing and passing through the separator while meeting the particle size requirements of the vertical mill finished product.

6. The method for reducing Fe content by crushing carbonized slag with a vertical mill according to claim 5, characterized in that: In the step 2, adjusting the separator parameters and dust collecting fan parameters during the continuous production process includes: adjusting the frequency of the dust collecting fan on the premise of meeting the particle size requirements of the finished product of the vertical mill, and matching the frequency of the dust collecting fan with the frequency of the separator.

7. The method for reducing Fe content by crushing carbonized slag by vertical mill according to claim 6, characterized in that: The frequency of the separator is 10-30 Hz, the frequency of the dust collecting fan is 40-50 Hz, and the air volume of the system is 60000-85000m 3 / h.

8. The method for reducing Fe content by crushing carbonized slag with a vertical mill according to claim 3, characterized in that: In the step three, discharging the material inside the vertical mill out of the vertical mill system after continuous production for a first time includes: lifting the grinding roller after continuous production for the first time, discharging the material inside the vertical mill to the outside of the vertical mill system for a second time, and then lowering the grinding roller.

9. The method for reducing Fe content by crushing carbonized slag by vertical mill according to claim 8, characterized in that: The first time is 3 to 4 hours, and the second time is 10 to 15 minutes.

10. The method for reducing Fe content by crushing carbonized slag with a vertical mill according to claim 3, characterized in that: In the step three, the mass percentage of iron in the materials discharged out of the vertical mill system is less than or equal to 38%.

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