A method for sintering treatment of magnetic separation powder

Abstract

The present application relates to the field of steel slag treatment, and particularly relates to a magnetic separation powder return sintering treatment method, comprising: obtaining different particle size magnetic separation powder; obtaining phosphorus content of each particle size magnetic separation powder; under the condition that each parameter of sintered ore meets production requirements, adjusting the addition priority of different particle size magnetic separation powder replacing ore powder into sintering mixed uniform material according to the surplus amount of sintered ore phosphorus load and the phosphorus content of each particle size magnetic separation powder. The present application calculates the proportion of different particle size magnetic separation powder replacing ore powder according to the surplus amount of sintered ore phosphorus load and the different characteristics of the phosphorus content of each particle size magnetic separation powder, and also determines the addition priority of each particle size magnetic separation powder according to the phosphorus content of each particle size magnetic separation powder, so as to maximize the addition amount of converter magnetic separation powder in sintering, to maximize the added value of magnetic separation powder, and to avoid the problem of sintered ore phosphorus load exceeding the standard caused by directly adding magnetic separation powder.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of steel slag treatment, and particularly relates to a magnetic separation powder resintering treatment method. BACKGROUND

[0002] Converter steelmaking is a process of producing steel in a converter by taking hot metal, scrap steel and ferroalloy as main raw materials, adding lime, dolomite and other slagging materials, and not using external energy, but relying on the physical heat of the iron liquid and the heat generated by the chemical reaction between the components of the iron liquid. After the converter smelting is completed, the qualified molten steel is cast into billets and transported to the rolling workshop for processing, and the steel slag produced is sent to the steel slag workshop for treatment. The steel slag refers to the molten slag discharged during the steelmaking process, which is composed of calcium, iron, silicon, magnesium, aluminum, manganese, titanium, sulfur, phosphorus and other oxides, and is an industrial solid waste. The discharge amount is 15-20% of the crude steel output, and the iron content is relatively high, about 20%, which has a certain smelting value. How to effectively treat the steel slag has been an important research topic for people.

[0003] At present, steel slag can be obtained by heat stewing-rod grinding-magnetic separation process to obtain magnetic separation powder and resintering recycling. However, the harmful elements in the steel slag are relatively high, especially the phosphorus element, which is easy to cause the phosphorus content of the subsequent blast furnace molten iron to exceed the standard, thereby affecting the quality of the steel product. In view of this, the patent document CN118147390A discloses a recycling treatment method of converter magnetic separation powder, which selects the magnetic separation powder with an iron grade of about 50% from the steel slag produced in the converter smelting process through crushing treatment and magnetic separation process, calculates the ore blending, adds it to the mixed material in the raw material yard, and transports it to the sintering plant to be roasted into finished sinter, and then sent to the blast furnace to smelt qualified molten iron, and finally sent to the converter to smelt qualified billets. This cycle realizes self-production and self-consumption in the plant, and reduces the environmental pressure of the society. However, due to the limitation of the phosphorus content of the sintered ore for producing various quality steels, the addition amount of the magnetic separation powder is still low, and how to further improve the addition amount of the magnetic separation powder needs to be solved. SUMMARY

[0004] Therefore, the technical problem to be solved by the present application is to overcome the low addition amount of the magnetic separation powder in the existing recycling treatment method of the magnetic separation powder, so as to provide a magnetic separation powder resintering treatment method to solve the above problems.

[0005] To achieve the above purpose, the present application provides the following technical scheme:

[0006] A magnetic separation powder resintering treatment method, comprising:

[0007] obtaining magnetic separation powder of different particle sizes;

[0008] obtaining the phosphorus content of each particle size of the magnetic separation powder;

[0009] Under the condition that each parameter of the sintered ore meets the production requirement, according to the surplus amount of the phosphorus load of the sintered ore and the phosphorus content of the magnetic separation powder of each particle size, the adding priority of the magnetic separation powder of different particle sizes which is replaced into the mixed uniform material of the sintered ore is adjusted.

[0010] Preferably, the iron grade of the magnetic separation powder of different particle sizes is 55-65%.

[0011] Preferably, the obtaining process of the magnetic separation powder of different particle sizes comprises the following steps: pretreating the steel slag, magnetically separating and recovering the slag steel, and rod grinding and re-magnetizing the remaining steel slag.

[0012] Preferably, the pretreatment is hot stewing. The mechanism involved is that the temperature stress and the hydrolysis of free calcium oxide generated after the steel slag is melted at high temperature and encounters water make the steel slag break.

[0013] Preferably, the frequency of the double magnetic roller in the re-magnetizing step is 45-50 Hz.

[0014] In the present application, the size of the particle size distribution range of the magnetic separation powder of different particle sizes and the number of particle size distribution groups can be set at will. The number of particle size distribution groups should be greater than or equal to 2 groups, for example, it can be set to 2 groups, 3 groups, 4 groups, 5 groups or even more groups. In order to meet the more accurate addition and achieve a higher addition amount, the number of particle size distribution groups should be greater than or equal to 3 groups. However, if the number of particle size distribution groups is too large, the process will be relatively complex.

[0015] Therefore, preferably in the present application, the rod grinding processes the remaining steel slag into five particle size distribution groups. The particle size distribution range of each group in the five particle size distribution groups can be set by itself, as long as it can cover the particle size range of the screened magnetic separation powder, for example, the particle size range of each group can be set to 0-3 mm, 3-5 mm, 5-8 mm, 8-12 mm, >12 mm, or 0-2 mm, 2-5 mm, 5-10 mm, 10-15 mm, >15 mm. The above ranges are all inclusive of the upper limit value but not the lower limit value, that is, 0-2 mm means that the particle size is greater than 0 mm and less than or equal to 2 mm.

[0016] Based on the different particle size distribution requirements of the particle size distribution groups, each particle size distribution group will obtain a different proportion of magnetic separation powder within a certain iron grade range. By obtaining the phosphorus content of different particle size distribution groups and cooperating with the surplus amount of the phosphorus load of the sintered ore, the proportion of the steel slag which can effectively achieve the best addition amount can be obtained.

[0017] The phosphorus content of each particle size magnetic separation powder can be directly detected, but based on the principle of simple processing process, the distribution of phosphorus element in different particle sizes is obtained by analyzing and fitting the distribution of phosphorus element in different particle sizes of magnetic separation powder with different phosphorus element contents, and the phosphorus content of each particle size is obtained according to the average phosphorus content of the magnetic separation powder.

[0018] In the present application, the particle size range of each particle size distribution group is respectively set as 0-2mm, 2-5mm, 5-10mm, 10-15mm, >15mm, and the 0-2mm magnetic separation powder accounts for 0-10%, the 2-5mm magnetic separation powder accounts for 5-10%, the 5-10mm magnetic separation powder accounts for 65-70%, the 10-15mm magnetic separation powder accounts for 10-15%, and the >15mm magnetic separation powder accounts for 0-10%, and the distribution of phosphorus element in each particle size distribution group is: a1=1.249b+0.001, a2=0.753b+0.009, a3=0.877b-0.008, a4=1.258b+0.007, a5=1.874b+0.021; wherein b is the average phosphorus content of the magnetic separation powder, %; a1-a5 is the phosphorus content of the 0-2mm, 2-5mm, 5-10mm, 10-15mm, >15mm five particle size magnetic separation powder, %.

[0019] In order to achieve the above-mentioned magnetic separation powder account requirements in each particle size distribution group after re-magnetic separation, the steel slag account of each particle size distribution group of the steel slag after rod milling treatment before re-magnetic separation is: 0-2mm steel slag accounts for 5-10%, 2-5mm steel slag accounts for 10-15%, 5-10mm steel slag accounts for 60-65%, 10-15mm steel slag accounts for 5-10%, and >15mm steel slag accounts for 0-10%.

[0020] In the present application, the formula for calculating the addition ratio of each particle size of the magnetic separation powder is: L-k=(H1a1+H2a2+H3a3+H4a4+H5a5)-p(H1+H2+H3+H4+H5), wherein L is the phosphorus load of sinter, %; k is the phosphorus content of the sinter mixing material without adding magnetic separation powder, %; H1-H5 is the addition ratio of 0-2mm, 2-5mm, 5-10mm, 10-15mm, >15mm five particle size magnetic separation powder in the sinter mixing material, %; p is the average phosphorus content of the ore powder replaced by the magnetic separation powder, %.

[0021] Preferably, the addition priority of the magnetic separation powder in the sinter mixing material is (2-5mm)>(5-10mm)>(0-2mm)>(10-15mm)>(>15mm).

[0022] Preferably, the ore powder is at least one of Indian powder, Jumbo powder, Australian PB powder, Yangdi powder, FMG ultra special powder, FMG mixed powder, Rovio River powder, Meishan concentrate powder and returned ore.

[0023] Preferably, when the sum of the addition proportions of the magnetic separation powders of each particle size is less than or equal to 0.5%, no magnetic separation powder is added to the sintering mixture.

[0024] In the present application, the process of magnetic separation and recovery of slag is as follows: the slag with a particle size of greater than or equal to 450 mm is preliminarily separated by using a sieve, and the remaining slag with a particle size of less than 450 mm is separated by using a suction cup.

[0025] The technical scheme of the present application has the following advantages:

[0026] 1. A sintering treatment method of magnetic separation powder, comprising: obtaining magnetic separation powders of different particle sizes; obtaining the phosphorus content of each particle size of the magnetic separation powder; under the condition that each parameter of the sinter meets the production requirements, adjusting the addition priority of the magnetic separation powder of different particle sizes to replace the ore powder into the sintering mixture according to the surplus amount of the phosphorus load of the sinter and the phosphorus content of each particle size of the magnetic separation powder. According to the characteristics of the different phosphorus contents of each particle size of the magnetic separation powder, the present application calculates the proportion of the magnetic separation powder of different particle sizes to replace the ore powder by using the surplus amount of the phosphorus load of the sinter, and determines the addition priority of each particle size of the magnetic separation powder according to the phosphorus content of each particle size of the magnetic separation powder, so as to maximize the addition amount of the converter magnetic separation powder in the sintering, to maximize the added value of the magnetic separation powder, and to avoid the problem of exceeding the phosphorus load of the sinter caused by directly adding the magnetic separation powder.

[0027] 2. In the sintering treatment method of the magnetic separation powder of the present application, the particle size distribution and iron grade of the converter magnetic separation powder are adjusted by adjusting the parameters of the rod mill and the double magnetic drum.

[0028] 3. In the sintering treatment method of the magnetic separation powder of the present application, the magnetic separation powder is treated as follows: the proportion of 0-2mm magnetic separation powder is 0-10%, the proportion of 2-5mm magnetic separation powder is 5-10%, the proportion of 5-10mm magnetic separation powder is 60-70%, the proportion of 10-15mm magnetic separation powder is 10-15%, and the proportion of >15mm magnetic separation powder is 0-10%. If all the magnetic separation powder is treated as a particle size magnetic separation powder with a lower phosphorus content (for example, all treated as 2-5mm particle size) in the converter slag treatment process, the effect can be improved, but the current treatment process does not have the conditions, the treatment cost will be much higher than the value of the magnetic separation powder itself, and the iron element recovery rate of the slag will be greatly reduced.

[0029] 4. In the sintering treatment method of the magnetic separation powder of the present application, when the sum of the addition proportions of each particle size of the magnetic separation powder is less than or equal to 0.5%, no magnetic separation powder is added to the sintering mixture, so as to avoid the problems of uneven sintering feeding and incomplete mixing caused by the low addition of the magnetic separation powder, and to avoid the problem of segregation of the sinter. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the specific embodiments of the present application or the prior art, the drawings required to be used in the description of the specific embodiments or the prior art will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort on the basis of these drawings.

[0031] Figure 1 is the phosphorus element distribution regularity fitting curve of the 0-2 mm particle size in the embodiment 1 of the present application;

[0032] Figure 2 is the phosphorus element distribution regularity fitting curve of the 2-5 mm particle size in the embodiment 1 of the present application;

[0033] Figure 3 is the phosphorus element distribution regularity fitting curve of the 5-10 mm particle size in the embodiment 1 of the present application;

[0034] Figure 4 is the phosphorus element distribution regularity fitting curve of the 10-15 mm particle size in the embodiment 1 of the present application;

[0035] Figure 5 is the phosphorus element distribution regularity fitting curve of the >15 mm particle size in the embodiment 1 of the present application. DETAILED DESCRIPTION

[0036] The following examples are provided to better further understand the present application, and do not limit the best embodiments described, and do not constitute a limitation on the content and protection scope of the present application. Any person under the inspiration of the present application or the combination of the present application with other prior art features can obtain any product same or similar to the present application, which falls within the protection scope of the present application.

[0037] The specific experimental steps or conditions are not indicated in the examples, and can be performed according to the operation or conditions of the conventional experimental steps described in the literature in the art. The reagents or instruments used are not indicated by the manufacturer, and are conventional reagent products that can be obtained by market purchase.

[0038] Example 1

[0039] The present embodiment provides a magnetic separation powder resintering treatment method, and the specific steps are as follows:

[0040] (1) Firstly, the distribution of phosphorus element in different particle sizes (0-2 mm, 2-5 mm, 5-10 mm, 10-15 mm, >15 mm) of the magnetic separation powder with an average phosphorus content in the range of 0.6-1.1% (specifically 0.6%, 0.65%, 0.7%, 0.75%, 0.8%, 0.85%, 0.9%, 0.95%, 1.0%, 1.05%, 1.1%) is analyzed and fitted to obtain the distribution rule of phosphorus element in different particle sizes. The fitting curve of the phosphorus element distribution rule of the magnetic separation powder in different particle sizes is shown in FIG. 1. The applicable range of the fitting curve is: 0-2 mm magnetic separation powder accounts for 0-10%, 2-5 mm magnetic separation powder accounts for 5-10%, 5-10 mm magnetic separation powder accounts for 65-70%, 10-15 mm magnetic separation powder accounts for 10-15%, and >15 mm magnetic separation powder accounts for 0-10%. For example, when all the treatment is 2-5 mm, it is no longer applicable. Figures 1-5

[0041] (2) The converter steel slag is subjected to hot stewing and magnetic separation to recover the slag steel, and then the remaining steel slag is subjected to rod grinding (the specific parameters are motor power 500 kW, motor speed 740 r / min, voltage 10000 V, and frequency 50 Hz) to obtain five particle size distributions of steel slag: 0-2 mm steel slag accounts for 5%, 2-5 mm steel slag accounts for 15%, 5-10 mm steel slag accounts for 65%, 10-15 mm steel slag accounts for 10%, and >15 mm steel slag accounts for 5%.

[0042] (3) The steel slag obtained in step (2) is subjected to magnetic separation, and the frequency of the magnetic separation double magnetic drum is 45 Hz to obtain five particle size distributions of the magnetic separation powder: 0-2 mm converter magnetic separation powder accounts for 7%, 2-5 mm converter magnetic separation powder accounts for 8%, 5-10 mm converter magnetic separation powder accounts for 68%, 10-15 mm converter magnetic separation powder accounts for 10%, and >15 mm converter magnetic separation powder accounts for 7%. The iron grade of the converter magnetic separation powder is 60%, and the average phosphorus content of the converter magnetic separation powder is 0.9%. According to the fitting curve obtained in step (1), the phosphorus content of each particle size is obtained: the phosphorus content of 0-2 mm converter magnetic separation powder is 1.1251%, the phosphorus content of 2-5 mm converter magnetic separation powder is 0.6867%, the phosphorus content of 5-10 mm converter magnetic separation powder is 0.7813%, the phosphorus content of 10-15 mm converter magnetic separation powder is 1.1392%, and the phosphorus content of >15 mm converter magnetic separation powder is 1.7076%.

[0043] ​(4) The phosphorus content of the sintered mixed material without adding magnetic separation powder is 0.065%, and 2-5 mm converter magnetic separation powder is used to replace FMG super special powder at a proportion of 1.1%, after adding the converter magnetic separation powder, the phosphorus content of the sintered mixed material is 0.0719%, the phosphorus content of the sinter is 0.0682%, and the phosphorus content of the blast furnace molten iron is 0.116%, which meets the requirement of process specification P < 0.12%, and has no effect on the next process.

[0044] Example 2

[0045] The embodiment provides a magnetic separation powder return sintering treatment method, and the specific steps are as follows:

[0046] (1) The converter steel slag is hot stewed and the slag steel is recovered by magnetic separation, and then the remaining steel slag is rod milled (the specific parameters are motor power 500 kW, motor speed 740 r / min, voltage 10000 V, and frequency 50 Hz) to obtain five particle size distribution steel slags: 0-2 mm steel slag accounts for 5%, 2-5 mm steel slag accounts for 15%, 5-10 mm steel slag accounts for 65%, 10-15 mm steel slag accounts for 10%, and >15 mm steel slag accounts for 5%.

[0047] (2) The steel slag obtained in step (1) is subjected to magnetic separation, and the frequency of the magnetic separation double magnetic drum is 45 Hz, to obtain five particle size distribution magnetic separation powders: 0-2 mm converter magnetic separation powder accounts for 7%, 2-5 mm converter magnetic separation powder accounts for 8%, 5-10 mm converter magnetic separation powder accounts for 68%, 10-15 mm converter magnetic separation powder accounts for 10%, and >15 mm converter magnetic separation powder accounts for 7%. The iron grade of the converter magnetic separation powder is 60%, and the average phosphorus content of the converter magnetic separation powder is 0.9%. According to the fitting curve obtained in example 1, the phosphorus element of each particle size is obtained: the phosphorus content of 0-2 mm converter magnetic separation powder is 1.1251%, the phosphorus content of 2-5 mm converter magnetic separation powder is 0.6867%, the phosphorus content of 5-10 mm converter magnetic separation powder is 0.7813%, the phosphorus content of 10-15 mm converter magnetic separation powder is 1.1392%, and the phosphorus content of >15 mm converter magnetic separation powder is 1.7076%.

[0048] (3) The phosphorus content of the sintered mixed material without adding magnetic separation powder is 0.065%, and 5-10 mm converter magnetic separation powder is used to replace FMG super special powder at a proportion of 0.95%, after adding the converter magnetic separation powder, the phosphorus content of the sintered mixed material is 0.072%, the phosphorus content of the sinter is 0.0684%, and the phosphorus content of the blast furnace molten iron is 0.116%, which meets the requirement of process specification P < 0.12%, and has no effect on the next process.

[0049] Example 3

[0050] The embodiment provides a magnetic separation powder return sintering treatment method, and the specific steps are as follows:

[0051] (1) The converter steel slag is subjected to hot stewing and magnetic separation to recover slag steel, and then the remaining steel slag is subjected to rod grinding (the specific parameters are motor power 500 kW, motor speed 740 r / min, voltage 10000 V, and frequency 50 Hz) to obtain five particle size distributions of steel slag: 0-2 mm steel slag accounts for 5%, 2-5 mm steel slag accounts for 15%, 5-10 mm steel slag accounts for 65%, 10-15 mm steel slag accounts for 10%, and >15 mm steel slag accounts for 5%.

[0052] (2) The steel slag obtained in step (1) is subjected to magnetic separation, and the frequency of the magnetic separation double magnetic drum is 45 Hz to obtain five particle size distributions of magnetic separation powder: 0-2 mm converter magnetic separation powder accounts for 7%, 2-5 mm converter magnetic separation powder accounts for 8%, 5-10 mm converter magnetic separation powder accounts for 68%, 10-15 mm converter magnetic separation powder accounts for 10%, and >15 mm converter magnetic separation powder accounts for 7%. The iron grade of the converter magnetic separation powder is 60%, and the average phosphorus content of the converter magnetic separation powder is 0.9%. According to the fitting curve obtained in Example 1, the phosphorus content of each particle size is obtained: the phosphorus content of 0-2 mm converter magnetic separation powder is 1.1251%, the phosphorus content of 2-5 mm converter magnetic separation powder is 0.6867%, the phosphorus content of 5-10 mm converter magnetic separation powder is 0.7813%, the phosphorus content of 10-15 mm converter magnetic separation powder is 1.1392%, and the phosphorus content of >15 mm converter magnetic separation powder is 1.7076%.

[0053] (3) The phosphorus content of the sinter mixed material without adding magnetic separation powder is 0.055%. According to a replacement ratio of 1.9%, 5-10 mm converter magnetic separation powder is used to replace Indian powder. After adding the converter magnetic separation powder, the phosphorus content of the sinter mixed material is 0.0677%, the phosphorus content of the sinter is 0.0643%, and the phosphorus content of the blast furnace molten iron is 0.110%, which meets the requirement of P<0.12% in the process specification and has no effect on the next process.

[0054] Example 4

[0055] The embodiment provides a magnetic separation powder sintering treatment method, and the specific steps are as follows:

[0056] (1) The converter steel slag is subjected to hot stewing and magnetic separation to recover slag steel, and then the remaining steel slag is subjected to rod grinding (the specific parameters are motor power 500 kW, motor speed 740 r / min, voltage 10000 V, and frequency 50 Hz) to obtain five particle size distributions of steel slag: 0-2 mm steel slag accounts for 5%, 2-5 mm steel slag accounts for 15%, 5-10 mm steel slag accounts for 65%, 10-15 mm steel slag accounts for 10%, and >15 mm steel slag accounts for 5%.

[0057] (2) The steel slag obtained in step (1) is subjected to magnetic separation, and the magnetic separation double-magnetic roller frequency is 45 Hz, to obtain five particle size distribution levels of magnetic separation powder, i.e., 0-2 mm converter magnetic separation powder accounting for 7%, 2-5 mm converter magnetic separation powder accounting for 8%, 5-10 mm converter magnetic separation powder accounting for 68%, 10-15 mm converter magnetic separation powder accounting for 10%, and >15 mm converter magnetic separation powder accounting for 7%. The iron grade of the converter magnetic separation powder is 60%, and the average phosphorus content of the converter magnetic separation powder is 0.9%. According to the fitting curve obtained in Example 1, the phosphorus content of each particle size level is obtained, i.e., the phosphorus content of 0-2 mm converter magnetic separation powder is 1.1251%, the phosphorus content of 2-5 mm converter magnetic separation powder is 0.6867%, the phosphorus content of 5-10 mm converter magnetic separation powder is 0.7813%, the phosphorus content of 10-15 mm converter magnetic separation powder is 1.1392%, and the phosphorus content of >15 mm converter magnetic separation powder is 1.7076%.

[0058] (3) The phosphorus content of the sintered mixed material without adding magnetic separation powder is 0.055%. According to a 1.4% addition ratio, 10-15 mm converter magnetic separation powder is used to replace Indian powder. After adding the converter magnetic separation powder, the phosphorus content of the sintered mixed material is 0.0691%, the phosphorus content of the sintered ore is 0.0656%, and the phosphorus content of the blast furnace molten iron is 0.113%, which meets the process specification requirement of P<0.12% and has no effect on the next process.

[0059] Example 5

[0060] The present embodiment provides a magnetic separation powder sintering treatment method, and the specific steps are as follows:

[0061] (1) The converter steel slag is subjected to hot stewing and magnetic separation to recover the slag steel, and then the remaining steel slag is subjected to rod grinding (the specific parameters are motor power 500 kW, motor speed 740 r / min, voltage 10000 V, and frequency 55 Hz) to obtain five particle size distribution levels of steel slag, i.e., 0-2 mm steel slag accounting for 10%, 2-5 mm steel slag accounting for 15%, 5-10 mm steel slag accounting for 60%, 10-15 mm steel slag accounting for 10%, and >15 mm steel slag accounting for 5%.

[0062] (2) The steel slag obtained in step (1) is subjected to magnetic separation, and the magnetic separation double-magnetic roller frequency is 50 Hz, to obtain five particle size distribution levels of magnetic separation powder, i.e., 0-2 mm converter magnetic separation powder accounting for 10%, 2-5 mm converter magnetic separation powder accounting for 10%, 5-10 mm converter magnetic separation powder accounting for 65%, 10-15 mm converter magnetic separation powder accounting for 8%, and >15 mm converter magnetic separation powder accounting for 7%. The iron grade of the converter magnetic separation powder is 65%, and the average phosphorus content of the converter magnetic separation powder is 0.8%. According to the fitting curve obtained in Example 1, the phosphorus content of each particle size level is obtained, i.e., the phosphorus content of 0-2 mm converter magnetic separation powder is 1.0002%, the phosphorus content of 2-5 mm converter magnetic separation powder is 0.6112%, the phosphorus content of 5-10 mm converter magnetic separation powder is 0.6936%, the phosphorus content of 10-15 mm converter magnetic separation powder is 1.0134%, and the phosphorus content of >15 mm converter magnetic separation powder is 1.5202%.

[0063] (3) The phosphorus content of the sintered mixed material without adding magnetic separation powder is 0.065%. According to a 1% addition ratio, 2-5 mm converter magnetic separation powder is used to replace FMG super fine powder. After adding the converter magnetic separation powder, the phosphorus content of the sintered mixed material is 0.071%, the phosphorus content of the sintered ore is 0.0674%, and the phosphorus content of the blast furnace molten iron is 0.115%, which meets the process specification requirement of P<0.12% and has no effect on the next process.

[0064] Example 6

[0065] The embodiment provides a magnetic separation powder sintering treatment method, and the specific steps are as follows:

[0066] (1) The converter steel slag is subjected to hot stewing and magnetic separation to recover the slag steel, and then the remaining steel slag is subjected to rod grinding (the specific parameters are motor power 500 kW, motor speed 740 r / min, voltage 10000 V, and frequency 53 Hz) to obtain five particle size distribution levels of steel slag, i.e., 0-2 mm steel slag accounting for 10%, 2-5 mm steel slag accounting for 10%, 5-10 mm steel slag accounting for 65%, 10-15 mm steel slag accounting for 10%, and >15 mm steel slag accounting for 5%.

[0067] (2) The steel slag obtained in step (1) is subjected to magnetic separation, and the frequency of the magnetic separation double magnetic roller is 45 Hz, to obtain five particle size distribution of the magnetic separation powder, i.e., 0-2 mm converter magnetic separation powder accounting for 10%, 2-5 mm converter magnetic separation powder accounting for 8%, 5-10 mm converter magnetic separation powder accounting for 68%, 10-15 mm converter magnetic separation powder accounting for 7%, and >15 mm converter magnetic separation powder accounting for 7%. The iron grade of the converter magnetic separation powder is 60%, and the average phosphorus content of the converter magnetic separation powder is 0.9%. According to the fitting curve obtained in Example 1, the phosphorus content of each particle size is obtained, i.e., the phosphorus content of 0-2 mm converter magnetic separation powder is 1.1251%, the phosphorus content of 2-5 mm converter magnetic separation powder is 0.6867%, the phosphorus content of 5-10 mm converter magnetic separation powder is 0.7813%, the phosphorus content of 10-15 mm converter magnetic separation powder is 1.1392%, and the phosphorus content of >15 mm converter magnetic separation powder is 1.7076%.

[0068] (3) The phosphorus content of the sinter mixed material without adding the magnetic separation powder is 0.065%, and the 5-10 mm converter magnetic separation powder is used to replace the FMG super fine powder at a proportion of 1%, and after adding the converter magnetic separation powder, the phosphorus content of the sinter mixed material is 0.073%, the phosphorus content of the sinter is 0.0693%, and the phosphorus content of the blast furnace molten iron is 0.119%, which meets the requirement of P<0.12% in the process specification and does not have any influence on the next process.

[0069] Obviously, the above examples are only examples for clearly illustrating but not limiting the embodiments. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. Here, all the embodiments are not required to be exhausted, and the obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A method for a magnetic separation powder resintering process, characterized by, The application relates to a method for preparing different particle size grades of magnetic separation powder. The method comprises the following steps: pretreating steel slag, recovering the steel slag by magnetic separation, rod grinding the remaining steel slag, and then performing magnetic separation to obtain the different particle size grades of magnetic separation powder. The method further comprises the following steps: obtaining the phosphorus content of each particle size grade of the magnetic separation powder. Under the condition that each parameter of the sintered ore meets the production requirement, the priority of adding the different particle size grades of the magnetic separation powder into the sintering mixing material is adjusted according to the surplus of the phosphorus load of the sintered ore and the phosphorus content of each particle size grade of the magnetic separation powder. The iron grade of the different particle size grades of the magnetic separation powder is 55-65%. The formula for calculating the adding proportion of each particle size of the magnetic separation powder is: ; Wherein, L is the sinter phosphorus load, %; k is the sinter mixing material phosphorus content without adding magnetic separation powder, %; n is the number of particle size grades divided by the magnetic separation powder, and the value is 2, 3, 4 or 5; H i is the proportion of the i-th particle size grade magnetic separation powder in the sinter mixing material, %; a i is the phosphorus content of the i-th particle size grade magnetic separation powder, %; p is the average phosphorus content of the mineral powder replaced by the magnetic separation powder, %; Phosphorus content a of each size fraction of the magnetic separation powder i The distribution of phosphorus in different size fractions is obtained by direct detection or by analyzing and fitting the phosphorus element distribution of different size fractions of the magnetic separation powder with different phosphorus element contents. The phosphorus content of each size fraction is obtained according to the average phosphorus content of the magnetic separation powder.

2. The magnetic separation powder resintering process according to claim 1, characterized by, The pretreatment is hot stewing.

3. The magnetic separation powder resintering process according to claim 1, characterized by, And / or, the rod grinding processes the remaining steel slag into the following proportions: 0-2 mm steel slag accounts for 5-10%, 2-5 mm steel slag accounts for 10-15%, 5-10 mm steel slag accounts for 60-65%, 10-15 mm steel slag accounts for 5-10%, and steel slag larger than 15 mm accounts for 0-10%. The frequency of the double magnetic drum in the magnetic separation step is 45-50 Hz.

4. The magnetic separation powder resintering process according to claim 1, wherein And / or, the magnetic separation step processes the magnetic separation powder into the following proportions: 0-2 mm magnetic separation powder accounts for 0-10%, 2-5 mm magnetic separation powder accounts for 5-10%, 5-10 mm magnetic separation powder accounts for 65-70%, 10-15 mm magnetic separation powder accounts for 10-15%, and magnetic separation powder larger than 15 mm accounts for 0-10%. The phosphorus content of each particle size grade of the magnetic separation powder is a1=1.249b+0.001, a2=0.753b+0.009, a3=0.877b-0.008, a4=1.258b+0.007, and a5=1.874b+0.021; wherein b is the average phosphorus content of the magnetic separation powder, %; a1-a5 are the phosphorus contents of the five particle size grades of the magnetic separation powder, i.e. 0-2 mm, 2-5 mm, 5-10 mm, 10-15 mm and larger than 15 mm, %.

5. The magnetic separation powder resintering process according to claim 4, wherein The calculation formula of the adding proportion of each particle size grade of the magnetic separation powder is L-k=(H1a1+H2a2+H3a3+H4a4+H5a5)-p(H1+H2+H3+H4+H5), wherein L is the phosphorus load of the sintered ore, %; k is the phosphorus content of the sintering mixing material without adding the magnetic separation powder, %; H1-H5 are the adding proportions of the five particle size grades of the magnetic separation powder in the sintering mixing material, i.e. 0-2 mm, 2-5 mm, 5-10 mm, 10-15 mm and larger than 15 mm, %; and p is the average phosphorus content of the ore powder replaced by the magnetic separation powder, %.

6. The magnetic separation powder resintering treatment method according to claim 4 or 5, characterized by, The adding priority of the magnetic separation powder in the sintering mixing material is (2-5 mm)>(5-10 mm)>(0-2 mm)>(10-15 mm)>(>15 mm).

7. The magnetic powder resintering process according to claim 4 or 5, wherein The ore powder is at least one of Indian powder, Jumbo powder, Australian PB powder, Yangdi powder, FMG super special powder, FMG mixed powder, Ruohe powder, Meishan fine powder and returned ore.

8. The magnetic separation powder resintering process according to claim 1 or 2, characterized by, When the sum of the adding proportions of each particle size grade of the magnetic separation powder is less than or equal to 0.5%, the magnetic separation powder is not added into the sintering mixing material.

9. The magnetic separation powder resintering process according to claim 1 or 2, characterized by, ​

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