Method for rapidly detecting total iron content of steel slag magnetic separation iron-rich material through melting method

Abstract

The invention provides a method for rapidly detecting the total iron content of a steel slag magnetic separation iron-rich material by a melting method, and relates to the technical field of comprehensive utilization of metallurgical solid waste resources, and the method comprises the following steps: firstly, uniformly mixing the steel slag magnetic separation iron-rich material with a reducing agent and a fluxing agent, putting into a graphite crucible, and heating until the mixed material is fully melted; then cooling the graphite crucible to room temperature to obtain an iron block, finally weighing the iron block, and calculating the total iron content of the steel slag magnetic separation iron-rich material according to the mass ratio of the iron block to the steel slag magnetic separation iron-rich material; the invention overcomes the technical problems of difficult sample preparation, large error and complex operation in the existing detection technology.

Description

Technical Field

[0001] The present invention relates to the technical field of comprehensive utilization of metallurgical solid waste resources, in particular to a method for rapidly detecting the total iron content of iron-rich materials from magnetic separation of steel slag using a melting method. Background Art

[0002] Steel slag is an industrial by-product of the steelmaking process. Its main components are oxides of elements such as calcium, magnesium, iron, silicon, and aluminum, and are also mixed with metallic iron particles. This part of iron and magnetic iron oxides can be enriched through magnetic separation and can be returned to the sintering process or steelmaking process as ingredients, which not only saves resources and reduces costs, but also reduces the amount of slag discharge.

[0003] The iron-rich material obtained by magnetic separation of steel slag contains a large amount of iron particles, has high hardness, and is difficult to prepare samples, which makes it difficult to use the total iron content detection and causes large errors.

[0004] Patent publication number CN115015469A discloses a method for detecting the total iron content of steel slag: First, the iron-containing material sample after magnetic separation of the steel slag is crushed, then subjected to magnetic separation to separate the residual iron and -3mm tailings. The total iron content of the tailings is measured chemically; the residual iron is smelted and deoxidized, and after slag and iron separation, the total iron content is measured using a direct reading spectrometer. Finally, the total iron content of the iron-containing material is calculated based on the weight ratio of the tailings and residual iron. This invention addresses the problem that conventional chemical testing methods cannot accurately determine the total iron content of slag steel, but the detection method is divided into two parts, with a long and complex operation process.

[0005] Patent publication number CN110887762A discloses a method for determining the mass fraction of metallic iron in slag samples: First, the bulk density M1 of a slag sample with a known iron content is measured, and the pure slag density Z is derived according to a specific formula. Next, the bulk density M2 of a slag sample of the same type as the slag sample is measured, and finally, the metallic iron mass fraction of the slag sample is derived based on the change in bulk density between the two. This method is simple to operate, requires minimal equipment, requires minimal investment, is low-cost, and is quick to produce. However, this method suffers from significant measurement errors, and the test results can only be used as a reference, and only for the same type of slag.

[0006] Patent publication number CN115326784A discloses a method for detecting the total iron content in hot-pressed iron blocks: samples are taken from different parts of the hot-pressed iron blocks, placed in a graphite crucible for electromagnetic induction melting, and rapidly cooled with water to form pig iron blocks; the pig iron blocks are cut and ground, and then a spark source atomic emission spectrometer is used to obtain the total iron content in the pig iron blocks, and then the total iron content in the hot-pressed iron blocks is calculated. This invention can truly reflect the quality of hot-pressed iron blocks and better guide ironmaking and steelmaking production. This method is mainly used for detecting the total iron content of hot-pressed steelmaking, but it has limitations for detecting the total iron content of iron-rich materials obtained by magnetic separation of steel slag, and the operation is relatively complicated.

[0007] In view of this, the present invention is particularly proposed. Summary of the Invention

[0008] The purpose of the present invention is to provide a method for rapidly detecting the total iron content of steel slag magnetic separation iron-rich materials by the melting method, overcoming the technical problems of difficult sample preparation, large error and complex operation in the existing detection technology; melting the iron-rich materials at high temperature, using a carbonaceous reducing agent to reduce the iron oxides in the iron-rich materials to metallic iron and enter the molten iron, cooling and then separating the molten slag, removing the iron blocks, and calculating the total iron content of the iron-rich materials through the mass ratio of the iron blocks to the iron-rich materials.

[0009] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0010] The present invention provides a method for rapidly detecting the total iron content of steel slag magnetic separation iron-rich materials by the melting method, including the following steps: First, uniformly mix the steel slag magnetic separation iron-rich materials with a reducing agent and a fluxing agent, put them into a graphite crucible and heat until the mixed materials are fully melted, then cool the graphite crucible to room temperature to obtain iron blocks, and finally weigh the iron blocks, and calculate the total iron content of the steel slag magnetic separation iron-rich materials through the mass ratio of the iron blocks to the steel slag magnetic separation iron-rich materials.

[0011] Further, the mass ratio of the steel slag magnetic separation iron-rich materials, the reducing agent and the fluxing agent is 100:(0.5 - 10):(0.4 - 4).

[0012] Further, the reducing agent is a carbonaceous reducing agent, and the carbonaceous reducing agent includes one or several of coke powder, semi-coke, and pulverized coal; and / or, the fluxing agent is fluorite, and the content of CaF2 in the fluorite is not less than 75%.

[0013] Further, the particle sizes of the reducing agent and the fluxing agent are both ≤3mm.

[0014] Further, the heating temperature is 1400 - 1700°C.

[0015] Further, the cooling is carried out by water cooling.

[0016] Further, the equipment used for the heating is an intermediate frequency melting furnace.

[0017] Further, remove the residue adhered to the surface of the obtained iron blocks before weighing the iron blocks.

[0018] The method for rapidly detecting the total iron content of steel slag magnetic separation iron-rich materials provided by the present invention has the following beneficial effects:

[0019] (1) The present invention does not require fine sample preparation for the sample, as long as the sample to be measured can be put into the graphite crucible.

[0020] (2) The method of the present invention measures a relatively large amount of the sample to be measured, which is more beneficial for improving the uniformity and representativeness of the sample, has a small detection error, and is simple to operate and highly efficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0022] Figure 1 It is a flowchart of the detection method provided by the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] To make the objectives, technical solutions, and advantages of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in combination with the embodiments of the present invention. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention. The process parameters not specified in the following embodiments are usually in accordance with conventional conditions.

[0024] In the present invention, the endpoints and any values within the disclosed ranges are not limited to the exact ranges or values. These ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed in the present invention.

[0025] The present invention provides a method for rapidly detecting the total iron content of steel slag magnetic separation iron-rich materials by the melting method, including the following steps: First, mix the steel slag magnetic separation iron-rich materials with a reducing agent and a flux evenly, put them into a graphite crucible and heat until the mixed materials are melted sufficiently, then cool the graphite crucible to room temperature to obtain iron blocks, and finally weigh the iron blocks, and calculate the total iron content of the steel slag magnetic separation iron-rich materials through the mass ratio of the iron blocks to the steel slag magnetic separation iron-rich materials.

[0026] The present invention mixes the iron-rich materials with a reducing agent and a flux and melts them in a graphite crucible to reduce the iron oxide to iron, and then separates the slag and iron.

[0027] As an alternative embodiment of the present invention, the mass ratio of the steel slag magnetic separation iron-rich material, the reducing agent and the flux is 100:(0.5 - 10):(0.4 - 4) (such as 100:1:1, 10:2:1, 100:3:1, 100:4:1, 100:5:1, 100:6:1, 100:7:1, 100:8:1, 100:9:1, 100:1:2, 100:2:2, 100:3:2, 100:4:2, 100:5:2, 100:6:2, 100:7:2, 100:8:2, 100:9:2, 100:1:3, 100:2:3, 100:3:3, 100:4:3, 100:5:3, 100:6:3, 100:7:3, 100:8:3, 100:9:3). Using a carbonaceous reducing agent has low cost, is easy to store, has less slag volume, and has little impact on the test results. The flux can reduce the slag dissolution temperature, improve the fluidity of the molten slag, and thus promote the timely entry of the reduced iron droplets in the slag into the molten iron, improving the test accuracy. The addition amount of the flux must be within a reasonable range. Adding too much or too little flux will cause a high slag melting point and poor fluidity. Poor fluidity means that the iron reduced from the slag cannot settle in the molten iron, resulting in a large error in the test results.

[0028] As an alternative embodiment of the present invention, the reducing agent is a carbonaceous reducing agent, and the carbonaceous reducing agent includes one or more of coke powder, semi-coke, and pulverized coal; and / or, the flux is fluorite, and the content of CaF2 in the fluorite is not less than 75% (such as 76%, 78%, 80%, 82%, 84%, 86%, 88%, 90%, 92%, 94%, 96%, 98%, 99%).

[0029] As an alternative embodiment of the present invention, the particle sizes of the reducing agent and the flux are both ≤ 3 mm (such as 0.1 mm, 0.5 mm, 1 mm, 1.5 mm, 2 mm).

[0030] As an alternative embodiment of the present invention, the heating temperature is 1400 - 1700 °C (such as 1450 °C, 1480 °C, 1500 °C, 1530 °C, 1550 °C, 1580 °C, 1600 °C, 1630 °C, 1650 °C, 1680 °C).

[0031] As an alternative embodiment of the present invention, the cooling is carried out by water cooling.

[0032] As an alternative embodiment of the present invention, the equipment for the heating is an intermediate frequency melting furnace.

[0033] As an alternative embodiment of the present invention, the residue adhered to the surface of the obtained iron block is removed before weighing the iron block.

[0034] The present invention will be further described in detail below in conjunction with specific examples and comparative examples. The processes of the following examples and comparative examples are all repeated three times, and the recorded mass of the iron blocks obtained is the average value of the three repetitions.

[0035] Example 1

[0036] (1) Crush the coke powder, and use a sample splitter sieve to screen out no less than 100 g of coke powder with a particle size of ≤ 3 mm for standby. Crush the fluorite, and use a sample splitter sieve to screen out no less than 50 g of fluorite with a particle size of ≤ 3 mm for standby.

[0037] (2) Weigh 512 g of steel slag magnetic separation iron-rich material 1, 6.2 g of coke powder, and 2.1 g of fluorite (with a CaF2 content of about 75%), mix them evenly, and load them into a graphite crucible.

[0038] (3) Place the graphite crucible in the middle of the intermediate frequency melting furnace coil, and start the intermediate frequency melting furnace to heat to about 1500 °C.

[0039] (4) After the materials are completely melted, take out the graphite crucible and quickly cool it to room temperature in cold water.

[0040] (5) Take out the iron block in the graphite crucible, and clean the adhered residue on the surface of the iron block with a wire brush.

[0041] (6) Weigh the cleaned iron block and record the mass of 453.8 g. After calculation, the total iron content of this iron-rich material is 88.63%.

[0042] Example 2

[0043] (1) Crush the coke powder, and use a sample splitter sieve to screen out no less than 100 g of coke powder with a particle size of ≤ 3 mm for standby. Crush the fluorite, and use a sample splitter sieve to screen out no less than 50 g of fluorite with a particle size of ≤ 3 mm for standby.

[0044] (2) Weigh 476 g of steel slag magnetic separation iron-rich material 2, 20.3 g of coke powder, and 12.1 g of fluorite (with a CaF2 content of about 75%), mix them evenly, and load them into a graphite crucible.

[0045] (3) Place the graphite crucible in the middle of the intermediate frequency melting furnace coil, and start the intermediate frequency melting furnace to heat to about 1500 °C.

[0046] (4) After the materials are completely melted, take out the graphite crucible and quickly cool it to room temperature in cold water.

[0047] (5) Take out the iron block in the graphite crucible, and clean the adhered residue on the surface of the iron block with a wire brush.

[0048] (6) Weigh the cleaned iron block and record the mass of 351.3 g. After calculation, the total iron content of this iron-rich material is 73.8%.

[0049] Example 3

[0050] (1) Crush the coke powder, and use a sample splitter sieve to screen out no less than 100 g of coke powder with a particle size ≤ 3 mm for standby. Crush the fluorite, and use a sample splitter sieve to screen out no less than 50 g of fluorite with a particle size ≤ 3 mm for standby.

[0051] (2) Weigh 532 g of steel slag magnetic separation iron-rich material 3, 46.2 g of coke powder, and 19.8 g of fluorite (CaF2 content is about 75%), mix them evenly, and put them into a graphite crucible.

[0052] (3) Place the graphite crucible in the middle of the intermediate frequency melting furnace coil, and start the intermediate frequency melting furnace to heat to about 1500 °C.

[0053] (4) After the materials are completely melted, take out the graphite crucible and quickly cool it to room temperature in cold water.

[0054] (5) Take out the iron block in the graphite crucible, and clean the adhered residue on the surface of the iron block with a wire brush.

[0055] (6) Weigh the cleaned iron block and record the mass of 34,270 g. After calculation, the total iron content of this iron-rich material is 64.42%.

[0056] Example 4

[0057] (1) Crush the coke powder, and use a sample splitter sieve to screen out no less than 100 g of coke powder with a particle size ≤ 3 mm for standby. Crush the fluorite, and use a sample splitter sieve to screen out no less than 50 g of fluorite with a particle size ≤ 3 mm for standby.

[0058] (2) Weigh 487 g of steel slag magnetic separation iron-rich material 1, 5.9 g of coke powder, and 3.0 g of fluorite (CaF2 content is about 75%), mix them evenly, and put them into a graphite crucible.

[0059] (3) Place the graphite crucible in the middle of the intermediate frequency melting furnace coil, and start the intermediate frequency melting furnace to heat to about 1500 °C.

[0060] (4) After the materials are completely melted, take out the graphite crucible and quickly cool it to room temperature in cold water.

[0061] (5) Take out the iron block in the graphite crucible, and clean the adhered residue on the surface of the iron block with a wire brush.

[0062] (6) Weigh the cleaned iron block and record the mass of 431.8 g. After calculation, the total iron content of this iron-rich material is 88.66%.

[0063] Comparative Example 1

[0064] (1) Crush the coke powder and use a sample splitter sieve to screen out no less than 100 g of coke powder with a particle size of ≤ 3 mm for standby. Crush the fluorite and use a sample splitter sieve to screen out no less than 50 g of fluorite with a particle size of ≤ 3 mm for standby.

[0065] (2) Weigh 487 g of steel slag magnetic separation iron-rich material 1, 5.9 g of coke powder, and 25 g of fluorite (with a CaF₂ content of about 75%), mix them evenly, and load them into a graphite crucible.

[0066] (3) Place the graphite crucible in the middle of the intermediate frequency melting furnace coil, and start the intermediate frequency melting furnace to heat to about 1500 °C.

[0067] (4) After the materials are completely melted, take out the graphite crucible and quickly cool it to room temperature in cold water.

[0068] (5) Take out the iron block in the graphite crucible and clean the adhered residues on the surface of the iron block with a wire brush.

[0069] (6) Weigh the cleaned iron block and record the mass of 429.3 g. After calculation, the total iron content of this iron-rich material is 88.15%.

[0070] Comparative Example 2

[0071] (1) Crush the coke powder and use a sample splitter sieve to screen out no less than 100 g of coke powder with a particle size of ≤ 3 mm for standby. Crush the fluorite and use a sample splitter sieve to screen out no less than 50 g of fluorite with a particle size of ≤ 3 mm for standby.

[0072] (2) Weigh 487 g of steel slag magnetic separation iron-rich material 1, 5.9 g of coke powder, and 1 g of fluorite (with a CaF₂ content of about 75%), mix them evenly, and load them into a graphite crucible.

[0073] (3) Place the graphite crucible in the middle of the intermediate frequency melting furnace coil, and start the intermediate frequency melting furnace to heat to about 1500 °C.

[0074] (4) After the materials are completely melted, take out the graphite crucible and quickly cool it to room temperature in cold water.

[0075] (5) Take out the iron block in the graphite crucible and clean the adhered residues on the surface of the iron block with a wire brush.

[0076] (6) Weigh the cleaned iron block and record the mass of 431.0 g. After calculation, the total iron content of this iron-rich material is 88.50%.

[0077] Analysis of effect data

[0078] According to the calculation results of Embodiment 1 and Embodiment 4, it can be seen that the error range of this method is about ±0.05%, and after the fluorite is in excess by 1.5 times, the total iron content increases by 0.03% compared with Embodiment 1. It can be seen that within a reasonable range, when the dosage of the flux increases, the slag viscosity decreases and the fluidity increases, which is beneficial for the reduced iron droplets to enter the molten iron in time. It can be seen that an appropriate amount of flux helps to improve the detection accuracy.

[0079] Comparing Comparative Example 1 (excessive fluorite) with Embodiment 4: The total iron content decreases by 0.51% compared with Embodiment 4 (88.66%). Excessive fluorite results in too strong slag fluidity, and some iron droplets are lost with the slag, reducing the iron recovery rate.

[0080] Comparing Comparative Example 2 (insufficient fluorite) with Embodiment 4: The total iron content decreases by 0.16% compared with Embodiment 4. Insufficient fluorite increases the slag viscosity, making it difficult for the iron droplets to separate, and significantly reducing the iron recovery rate.

[0081] Based on the above analysis, when the dosage of fluorite is higher than the limit value, the iron recovery rate will decrease and the total iron content will decrease. When the dosage of fluorite is lower than the limit value, the slag fluidity will be poor, it will be difficult to separate the iron droplets, and the total iron content will decrease significantly. The dosage of the flux (fluorite) needs to be strictly controlled within a reasonable range (such as the mass ratio of the iron-rich material by magnetic separation of steel slag to the flux is 100:(0.4 - 4)) to ensure the balance of slag fluidity and iron recovery rate.

[0082] Finally, it should be noted that: The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: They can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for rapidly detecting the total iron content of magnetically separated iron-rich materials from steel slag by the melting method, characterized in that, It includes the following steps: First, evenly mix the steel slag magnetic separation iron-rich material with the reducing agent and the flux, put it into a graphite crucible and heat it until the mixed material melts sufficiently. Then, cool the graphite crucible to room temperature to obtain iron blocks. Finally, weigh the iron blocks, and calculate the total iron content of the steel slag magnetic separation iron-rich material through the mass ratio of the iron blocks to the steel slag magnetic separation iron-rich material.

2. The method for rapidly detecting the total iron content of the iron-rich material by magnetic separation of steel slag by the melting method according to claim 1, characterized in that, The mass ratio of the steel slag magnetic separation iron-rich material, the reducing agent and the flux is 100:(0.5 - 10):(0.4 - 4).

3. The method for rapidly detecting the total iron content of the iron-rich material by magnetic separation of steel slag by the melting method according to claim 1, characterized in that, The reducing agent is a carbonaceous reducing agent, and the carbonaceous reducing agent includes one or more of coke powder, semi-coke, and pulverized coal; and / or, the flux is fluorite, and the content of CaF2 in the fluorite is not less than 75%.

4. The method for rapidly detecting the total iron content of the steel slag magnetic separation iron-rich material by the melting method according to claim 1, characterized in that The particle sizes of both the reducing agent and the flux are ≤3mm.

5. The method for rapidly detecting the total iron content of the iron-rich material by magnetic separation of steel slag by the melting method according to claim 1, characterized in that, The heating temperature is 1400 - 1700°C.

6. The method for rapidly detecting the total iron content of the steel slag magnetic separation enriched iron material by the melting method according to claim 1, characterized in that, The cooling is carried out by water cooling.

7. The method for rapidly detecting the total iron content of the iron-rich material by magnetic separation of steel slag by the melting method according to claim 1, characterized in that, The equipment used for the heating is an intermediate frequency melting furnace.

8. The method for rapidly detecting the total iron content of the iron-rich material obtained by magnetic separation of steel slag by the melting method according to claim 1, characterized in that, Before weighing the iron blocks, remove the residues adhered to the surface of the obtained iron blocks.

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