Method for detecting content of each element in steel scrap blank

Abstract

The invention discloses a method for detecting the content of each element in a steel scrap blank. The method comprises the following steps: step 1, obtaining a plurality of steel scrap blanks with millimeter-scale particle sizes; 2, the steel scrap blanks with the millimeter-level particle sizes are sampled; step 3, grinding each sample obtained by sampling by using a grinding machine; step 4, respectively obtaining woolen materials with a plurality of mesh-level particle sizes corresponding to each millimeter-level particle size, and calculating the proportion of the woolen materials with each mesh-level particle size; 5, the total iron content of the raw materials with the particle sizes of all the mesh levels is measured; step 6, obtaining the iron element content in the steel scrap blanks by using a content calculation formula according to the proportion of the blanks with the particle sizes of various meshes in the step 4 and the total iron content of the blanks with the particle sizes of various meshes in the step 5; physical screening, chemical detection and data calculation are integrated, a reusable detection process is formed, and the detection error rate is smaller than or equal to 1.5%; the detection precision is + / -0.5%, accurate judgment of the iron content of the steel scrap blank is achieved, and the impurity recognition rate is increased to 95%.

Description

Technical Field

[0001] The invention belongs to the field of inspection of iron raw material steel scraps, and in particular relates to a method for detecting the content of various elements in the steel scraps. Background Art

[0002] Steel scrap is the waste debris generated during the turning, milling, drilling, and grinding processes of steel. It is primarily composed of iron, but also contains oil, rust, emulsions, and other impurities introduced during processing and transportation. Due to the diverse sources and varying forms of steel scrap, the actual iron content and contribution to steel consumption cannot be visually determined. Existing techniques typically use magnets to detect non-steel debris, but this method is unable to identify the actual iron content of the steel scrap. Summary of the Invention

[0003] The purpose of the present invention is to provide a method for detecting the content of various elements in steel scraps, so as to solve the problem that the existing technology only uses a magnetic suction method to check whether other non-steel scraps are contained, and cannot identify the actual iron content of the steel scraps.

[0004] The present invention adopts the following technical solution: a method for detecting the content of each element in steel scrap raw material, comprising:

[0005] Step 1: Classify the collected steel scraps to obtain steel scraps with multiple millimeter-level particle sizes; dry the steel scraps with multiple millimeter-level particle sizes separately and calculate the proportion of solid matter after drying;

[0006] Step 2: Sample steel scraps of various millimeter-sized particle sizes respectively;

[0007] Step 3: Grind each sample obtained by sampling using a grinder;

[0008] Step 4: Screen each ground sample again to obtain multiple mesh-size raw materials corresponding to each millimeter-level particle size, and calculate the proportion of raw materials of each mesh-size raw material;

[0009] Step 5: using the titanium trichloride potassium dichromate volumetric method to determine the total iron content of the wool material of each mesh size;

[0010] Step 6: According to the proportion of the raw materials of each mesh size in step 4 and the total iron content of the raw materials of each mesh size in step 5, the iron content in the raw materials of each mesh size is obtained using the content calculation formula.

[0011] The beneficial effects of the present invention are:

[0012] The present invention firstly collects samples on site according to three particle sizes: >3mm, 1-3mm, and <1mm, and then prepares samples by combining secondary screening (<14 mesh, 14-80 mesh, and >80 mesh) to cover the entire particle size range;

[0013] The present invention establishes a content calculation formula based on particle size distribution, volatile matter ratio and chemical composition, and outputs the particle contribution and impurity impact assessment;

[0014] The present invention integrates physical screening, chemical testing, and data calculation to form a reusable inspection process with a detection error rate of ≤1.5% and a detection accuracy of ±0.5%, enabling accurate determination of the iron content of steel scraps and raw materials, and increasing the impurity identification rate to 95%, helping to reduce procurement costs by 10%-15%.

[0015] The present invention can also detect the content of other elements in the raw material, covering the physical form (particle size distribution, volatiles) and chemical composition (TFe, SiO2, P, etc.) of the steel scrap raw material, providing multi-dimensional data support, and avoiding the one-sidedness of the traditional magnetic separation method that only detects magnetic impurities. DETAILED DESCRIPTION

[0016] The present invention is described in detail below with reference to specific embodiments.

[0017] The present invention discloses a method for detecting the content of various elements in steel scraps, comprising:

[0018] Step 1: Classify the collected steel scraps to obtain steel scraps with multiple millimeter-level particle sizes; dry the steel scraps with multiple millimeter-level particle sizes separately and calculate the proportion of solid matter after drying;

[0019] Step 2: Sample steel scraps of various millimeter-sized particle sizes respectively;

[0020] Step 3: Grind each sample obtained by sampling using a grinder;

[0021] Step 4: Screen each ground sample again to obtain multiple mesh-size raw materials corresponding to each millimeter-level particle size, and calculate the proportion of raw materials of each mesh-size raw material;

[0022] Step 5: using the titanium trichloride potassium dichromate volumetric method to determine the total iron content of the wool material of each mesh size;

[0023] Step 6: According to the proportion of the raw materials of each mesh size in step 4 and the total iron content of the raw materials of each mesh size in step 5, the iron content in the raw materials of each mesh size is obtained using the content calculation formula.

[0024] Preferably, the content calculation formula in step 5 is:

[0025] X=Σ(Y×H×Z)

[0026] Among them, X is the content of a certain element, Y is the proportion of raw materials of each mesh size; H is the proportion of solid matter after drying of steel scrap raw materials of each millimeter particle size; Z is the measured element content of raw materials of each mesh size.

[0027] Preferably, step 5 further includes: measuring the content of silicon dioxide using a silicon molybdenum blue photometry method, and then obtaining the content of silicon in the steel scrap raw material using a content calculation formula.

[0028] Preferably, step 5 further comprises: measuring the phosphorus content by using a phosphorus bismuth molybdenum blue photometry method, and then obtaining the phosphorus content in the steel scrap raw material by using a content calculation formula.

[0029] Preferably, step 5 further comprises: measuring the contents of calcium, magnesium and aluminum by using an EDTA method, and then obtaining the contents of calcium, magnesium and aluminum in the steel scrap by using a content calculation formula.

[0030] Preferably, the multiple millimeter-scale particle sizes in step 1 are particle sizes >3 mm, 1-3 mm, and <1 mm, respectively.

[0031] Preferably, the millimeter-scale particle sizes in step 2 are respectively >80 mesh, 14-80 mesh, and <14 mesh.

[0032] Example

[0033] On February 11th, the Metrology and Communication Station delivered a steel scrap material sample, vehicle number (Jin MM0866). The sample was sampled using the unloading method: a forklift pushed a longitudinal section along the centerline of the material, with three points evenly spaced along the section. The sample weight was no less than 10 kg. The weight and proportion of the three particle sizes (>3mm, 1-3mm, and <1mm) were measured on-site. The data was recorded and delivered to the laboratory along with the steel scrap material sample. The sample size distribution was: >3mm 8.30 kg, 1-3mm 2.21 kg, <1mm 0.21 kg, for a total weight of 10.72 kg.

[0034] 500 grams of each of the three particle size samples were cut out and dried at 105°C for 90 minutes. After cooling to room temperature, they were weighed. The proportions of the three samples after drying were calculated, and the proportions of each particle size sample and the proportions after drying were filled in on the sample bag. The specific data are shown in Table 1.

[0035] Table 1 Percentage of volatile matter

[0036]

[0037]

[0038] 200 grams of each sample after drying is separated and ground with a grinder, sieved with 14 mesh and 80 mesh standard sieves respectively, and bagged. The samples sieved with <14 mesh, 14-80 mesh, and >80 mesh are put into sample bags respectively. The sample bags are clearly marked with the grams of <14 mesh, 14-80 mesh, and >80 mesh, as well as the total grams.

[0039] Determination of particulate matter: Weigh the remaining sample after preparation and the weight of the particulate matter after iron removal, record the data, fill it in on the sample bag, take a photo, grind the particulate matter and bag it.

[0040] Sample preservation: After preparation, all remaining samples should be preserved for future testing.

[0041] Steel scrap raw material composition analysis

[0042] Total iron analysis: titanium trichloride potassium dichromate volumetric method

[0043] Weigh 0.2000g of the sample into a 500mL conical flask, add approximately 0.5g of sodium fluoride and 50mL of concentrated hydrochloric acid, and dissolve by heating at low temperature. Remove the sample when the volume is concentrated to 10-15mL. Rinse the flask with hot water, then place it on a low-temperature electric hot plate and heat until it is slightly boiling. Remove the sample and, while still hot, add tin dichloride solution dropwise while shaking until the solution turns light yellow. Immediately rinse the flask with water to about 100mL, and cool to room temperature. Add 15 drops of sodium tungstate solution, then add 2-3 drops of titanium trichloride solution until the solution turns blue. Then, add (1+4) potassium dichromate solution until the blue color just disappears. Add 20mL of sulfur-phosphorus mixed acid solution and 3 drops of sodium diphenylamine sulfonate solution. Immediately add potassium dichromate standard solution until a stable purple color is achieved.

[0044] Determination of silicon dioxide: molybdenum blue photometric method

[0045] Weigh 0.2500 g of sample, add 0.5 g of mixed flux and mix well, wrap it tightly with half a piece of quantitative filter paper, then fold it into four layers with a piece of quantitative filter paper, moisten it with water, and stick it close to the bottom of a porcelain crucible. Place the sample bag on it, put the porcelain crucible into a muffle furnace at 880±5℃ and melt it for 10 minutes. After taking it out and cooling, pour it into a 300 mL beaker, add 100 mL of nitric and sulfuric acid mixture, and heat it slowly on a low-temperature electric furnace (if red appears, add a few drops of hydrogen peroxide until the red disappears). After it is completely dissolved, filter it with rapid quantitative filter paper into a 250 mL volumetric flask, wash the filter paper with water several times, dilute to the scale after cooling, and mix it well as the mother liquor for the determination of SiO2, CaO, MgO, Al2O3, P, and Cu.

[0046] Pipette 1.00 mL of the mother liquor into a 150 mL conical flask, add 4 mL of ammonium molybdate solution, heat in a boiling water bath for 30 seconds, immediately add 5 mL of oxalic acid solution, 2 mL of ammonium ferrous sulfate solution, and 50 mL of water, shake well, and measure the absorbance at a wavelength of 680 nm with water as a reference using a 3 cm cuvette.

[0047] Determination of phosphorus: bismuth phosphate molybdenum blue photometric method

[0048] Pipette 10.00 mL of the mother liquor into a dry 150 mL Erlenmeyer flask, add 10 mL of nitric acid-bismuth nitrate, add 10 mL of ammonium molybdate-potassium sodium tartrate solution, shake while adding, add 5 mL of ascorbic acid-ethanol solution, add 20 mL of water, shake well, develop color in a boiling water bath for 40 seconds, and perform colorimetry at 680 nm using a 3 cm cuvette with water as the blank.

[0049] Determination of calcium oxide and magnesium oxide: EDTA complexometric titration

[0050] Determination of calcium oxide: Pipette 15.00 mL of mother liquor into a 250 mL conical flask, add 50 mL of water, 1 mL of magnesium sulfate solution, 5 mL of triethanolamine solution, 10 mL of potassium hydroxide solution, and 2-3 drops of calcium indicator, and immediately add EDTA standard solution until the blue color just appears.

[0051] Combined determination of calcium oxide and magnesium oxide: Pipette 15.00 mL of the mother liquor into a 250 mL conical flask, add 50 mL of water, 5 mL of triethanolamine solution, 10 mL of ammonia buffer solution, about 4 mL of Cu-EDTA solution, and 2-3 drops of PAN indicator, and immediately add EDTA standard solution until bright yellow color just appears.

[0052] Determination of aluminum oxide: Pipette 50.00 mL of the mother liquor into a 300 mL beaker, add 1 mL of nitric acid (1+1), heat to boil, add potassium hydroxide solution (20%) until reddish-brown ferric hydroxide appears in the solution, then add 10 mL more, heat to boil, and allow the precipitate to condense. Filter through quantitative filter paper into a 500 mL conical flask, and wash with potassium hydroxide solution (2%). To the separated precipitate, add 10 mL of concentrated hydrochloric acid, 15.00 mL of ETA standard solution, and 6-7 drops of bromophenol green indicator. Add ammonia (1+1) dropwise until a sky-blue color appears. Add approximately 5 mL of glacial acetic acid until the solution turns yellow. Heat to boil for 2 minutes, then add 13 drops of PAN indicator. Add copper sulfate standard solution dropwise until the solution turns purple-red.

[0053] Sulfur-infrared carbon-sulfur analysis method, the operation method adopts conventional method.

[0054] Table 2 Composition of steel scraps

[0055]

[0056]

[0057] The iron content of the steel scrap raw material is calculated based on the data in Table 2. The specific data are shown in Table 3.

[0058] Table 3 Calculation of iron content of steel scraps

[0059]

[0060] In Table 3, the proportion of the raw material is the proportion of each particle size sample in the raw material, such as 77.43% = 8.30 / 10.72*100%, and so on.

[0061] Therefore, TFe (%) of >3mm wool = 77.43% * 95.86% * 73.31% = 54.41%;

[0062] Therefore, TFe (%) of 1-3 mm wool = 20.62% * 96.06% * 60.73% = 12.03%;

[0063] Therefore, TFe (%) of the <1 mm wool material = 1.95% * 98.85% * 61.22% = 1.18%.

[0064] Therefore, the total iron content of steel scrap raw material = 54.41% + 12.03% + 1.18% = 67.62%.

[0065] The particulate matter and composition of the remaining samples were analyzed, and the specific data are shown in Tables 4 and 5.

[0066] Table 4 Particulate matter ratio

[0067] Material particle size Total weight (g) Weight of magnetic material (g) Particle weight (g) Particulate matter ratio (%) >3mm 279.7 202.9 76.8 27.46 1-3mm 277.2 169.5 107.7 38.85 <1mm 173.3 173.3 0 0

[0068] Table 5 Composition of steel scrap particles

[0069]

[0070] Therefore, the composition of the wool and the content of the corresponding elements can be judged according to Table 3, Table 4, and Table 5, and then whether the wool is qualified can be judged.

[0071] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for detecting the content of various elements in steel scraps, characterized in that: include: Step 1: Classify the collected steel scraps to obtain steel scraps with multiple millimeter-level particle sizes; Dry steel scraps of various millimeter-sized sizes separately and calculate the percentage of solid matter after drying. Step 2: Sample steel scraps of various millimeter-sized particle sizes respectively; Step 3: Grind each sample obtained by sampling using a grinder; Step 4: Screen each ground sample again to obtain multiple mesh-size raw materials corresponding to each millimeter-level particle size, and calculate the proportion of raw materials of each mesh-size raw material; Step 5: using the titanium trichloride potassium dichromate volumetric method to determine the total iron content of the wool material of each mesh size; Step 6: According to the proportion of the raw materials of each mesh size in step 4 and the total iron content of the raw materials of each mesh size in step 5, the iron content in the raw materials of each mesh size is obtained using the content calculation formula.

2. The method for detecting the content of each element in steel scraps according to claim 1, characterized in that: The content calculation formula in step 5 is: X=Σ(Y×H×Z) Among them, X is the content of a certain element, Y is the proportion of raw materials of each mesh size; H is the proportion of solid matter after drying of steel scrap raw materials of each millimeter particle size; Z is the measured element content of raw materials of each mesh size.

3. The method for detecting the content of each element in steel scraps according to claim 1, characterized in that: Step 5 also includes: measuring the content of silicon dioxide using a silicon molybdenum blue photometry method, and then obtaining the content of silicon in the steel scrap raw material using a content calculation formula.

4. The method for detecting the content of each element in steel scraps according to claim 1, characterized in that: Step 5 also includes: measuring the phosphorus content using the phosphorus bismuth molybdenum blue photometry method, and then obtaining the phosphorus content in the steel scrap raw material using a content calculation formula.

5. The method for detecting the content of each element in steel scraps according to claim 1, characterized in that: Step 5 also includes: measuring the contents of calcium, magnesium and aluminum using the EDTA method, and then obtaining the contents of calcium, magnesium and aluminum in the steel scrap using a content calculation formula.

6. The method for detecting the content of each element in steel scrap according to claim 1, characterized in that: The multiple millimeter-scale particle sizes in step 1 are respectively particle sizes >3 mm, 1-3 mm, and <1 mm.

7. The method for detecting the content of each element in steel scraps according to claim 1, characterized in that: The millimeter-scale particle sizes in step 2 are respectively >80 mesh, 14-80 mesh, and <14 mesh.

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