Method for measuring content of iron phase in iron-containing dust mud

Abstract

The invention relates to the technical field of chemical analysis, and relates to a method for measuring the content of an iron phase in iron-containing dust slime, which comprises the following steps: 1, preparing an iron-containing dust slime sample, and carrying out ball milling processing on the iron-containing dust slime to obtain an iron phase sample; 2, weighing an iron phase sample A0, placing the iron phase sample A0 in a container, adsorbing magnetic substances in the iron phase sample A0 by adopting a magnet, respectively weighing the adsorbed magnetic substance A1 and the remaining sample A '0, and detecting the content of magnetic metal iron in the magnetic substance A1 by utilizing a potassium dichromate method; step 3, mixing the residual sample A '0 with anhydrous sodium carbonate according to a mass fraction ratio of 1: (2-5), marking the mass fraction ratio of the anhydrous sodium carbonate to the residual sample A' 0 as k, and marking the fully ground and uniformly mixed sample as A '' 0; respectively detecting the contents of wFe < 1 >, wFe < 2 > and wFe < 3 > in the weighed uniformly mixed sample by using a potassium dichromate method; and 4, carrying out normalization calculation on the content results obtained in the step 2 and the step 3 to finally obtain the contents of total iron (TFe), metallic iron (MFe), ferrous iron (Fe < 2 + >) and ferric iron (Fe < 3 + >) in the iron phase sample A0.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical analysis, in particular to a method for determining the content of iron phase in iron-containing dust and mud. Background Art

[0002] During the production process, steel companies inevitably produce iron-containing waste (iron-containing dust and mud), such as blast furnace dust and mud, converter dust and mud, sintering dust removal ash, blast furnace gas ash, etc. Efficiently recycling and utilizing the effective elements in steel metallurgical dust and mud and realizing the recycling of all iron-containing dust and mud resources are undoubtedly important contents of developing a circular economy in the steel industry.

[0003] Since the iron phases in the iron-bearing dust are complex, such as total iron (TFe), metallic iron (MFe), divalent iron (Fe 2+ ), ferric iron (Fe 3+ ) Different phases of iron structure, different iron phases have different recovery difficulties and values. Therefore, determining the content of different iron phase types helps to select the best recovery process. Summary of the Invention

[0004] In order to overcome the defects of the prior art, the technical problem solved by the present invention is to provide a method for determining the content of iron phases in iron-containing dust and mud, which can determine the specific content of different types of iron phases.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A method for determining the iron phase content in iron-containing dust and mud comprises the following steps:

[0007] Step 1: Prepare an iron-containing dust mud sample and ball-mill the iron-containing dust mud to obtain an iron phase sample;

[0008] Step 2: Weigh the iron phase sample A0, place it in a container, use a magnet to adsorb the magnetic material in it, weigh the adsorbed magnetic material A1 and the remaining sample A'0 respectively, and use the potassium dichromate method to detect the magnetic metal iron content in the magnetic material A1. The magnetic metal iron content is recorded as wMFe 磁 ;

[0009] Step 3: Mix the remaining sample A'0 with anhydrous sodium carbonate in a mass fraction ratio of 1:(2-5), the mass fraction ratio of anhydrous sodium carbonate to the remaining sample A'0 is recorded as k, and the sample after thorough grinding and mixing is recorded as A"0; weigh the mixed samples from sample A"0 respectively, and use potassium dichromate method to detect wFe in the weighed mixed samples 合1 、wFe 合2 , and wFe 合3 Content; among them, wFe 合1is the sum of the remaining metallic iron, ferric iron, and ferrous iron in the mixed sample, which is ∑MFe′+Fe 3+ +Fe 2+ ;wFe 合2 is the sum of the remaining metallic iron and divalent iron in the mixed sample, which is ∑Fe 2+ +MFe′;wFe 合3 is the sum of three times the residual metallic iron and divalent iron in the mixed sample, which is ∑Fe 2+ +3MFe′;

[0010] Step 4: Normalize the content results obtained in steps 2 and 3, and finally obtain the content of total iron (TFe), metallic iron (MFe), divalent iron (Fe 2+ ), ferric iron (Fe 3+ ) content;

[0011] The calculation formula is as follows:

[0012]

[0013] w Fe 3+ =(wFe 合1 -wFe 合2 )×(k+1)×m′0 / m0…………Formula (3)

[0014] w TFe =(wFe 合1 ×(k+1)×m′0+wMFe 磁 ×m1) / m0…………Formula (4)

[0015] In the above formula:

[0016] m0—mass of iron phase sample A0;

[0017] m1—mass of magnetic material A1;

[0018] m′0—mass of the remaining sample A′0;

[0019] w MFe —The content of metallic iron in the iron phase sample A0;

[0020] w Fe 2+ —The content of ferrous iron in the iron phase sample A0;

[0021] w Fe 3+ —The content of ferric iron in the iron phase sample A0;

[0022] w TFe —Total iron content in iron phase sample A0.

[0023] In the step 1, an iron-containing dust mud sample is prepared, wherein the iron-containing dust mud sample has a total iron (TFe) mass fraction of 30-80%, a metallic iron (MFe) mass fraction of 5.0-70%, and a divalent iron (Fe 2+ ) mass fraction 0.3~40%, trivalent iron (Fe 3+ ) mass fraction of 0.2 to 15%; after ball milling the iron-containing dust, take out the undersize material with a particle size of ≤0.6 mm; quarter the undersize material once, ball mill it, and the discharge particle size is ≤0.18 mm; then quarter the undersize material twice, ball mill it, and the discharge particle size is ≤0.10 mm; quarter the undersize material three times, ball mill it, and the discharge particle size is ≤0.075 mm; mix the undersize material after the third ball milling, and after mixing for 150 to 400 seconds, obtain an iron phase sample, and the mass of the iron phase sample is controlled at 300 to 600 g.

[0024] The mass m0 of the iron phase sample A0 weighed is 10.0000~20.0000g. The iron phase sample A0 is placed at 150~400cm 3 In the container, a round or square magnet with a magnetic force greater than 1 Tesla is placed in a self-sealing bag and placed close to sample A0 for adsorption. The adsorbed magnetic material is collected in the sample bag; the remaining sample in the container is stirred and then adsorbed for the second time. This operation is repeated 3 to 5 times. The magnetic material finally collected in the sample bag is fully mixed to obtain magnetic material A1 and the remaining sample A′0 in the container, and they are weighed separately.

[0025] The potassium dichromate method was used to detect wMFe in magnetic material A1. 磁 The specific steps are as follows:

[0026] Weigh magnetic substance A1, record its mass as m2, place it in a glass conical flask, add hydrochloric acid with a density of ρ1.19 g / mL; heat at 280-320°C to dissolve, add stannous chloride solution dropwise until the color turns light yellow, and concentrate the volume to 10-15 mL; then wait for 1-2 minutes before adding sulfuric acid solution, add sodium tungstate solution, and adjust the color with titanium trichloride solution until a stable dark blue appears. Then, add potassium dichromate solution (1 / 6K2Cr2O7) dropwise until the blue color of the solution completely fades, stop, and add water to adjust the solution volume to 80-100 mL; after cooling to room temperature, add phosphoric acid, sulfuric acid solution, and sodium diphenylamine sulfonate solution, and add potassium dichromate solution dropwise until a stable purple color appears.

[0027] Among them, the ratio of hydrochloric acid volume to m2 is (20~60)mL:(0.2~3.0)g; the ratio of sulfuric acid volume (1:2~9) added each time to m2 is (5~60)mL:(0.2~3)g; the ratio of potassium dichromate concentration to m2 is (0.0500~0.5000)mol / L; (0.2~3)g.

[0028] wFe in sample A″0 after magnetic attraction 合1 Determination of content:

[0029] Weigh the A″0 sample, record the mass as m3, place it in a glass conical flask, add hydrochloric acid with a density of ρ1.19g / mL and potassium fluoride solution; heat at 280-320℃ to dissolve, and concentrate the volume to 10-15mL; add stannous chloride solution dropwise until the color turns light yellow; remove and cool for 5-10min, use a suction filtration device with a gasket and wet absorbent cotton to filter out a large amount of free carbon in the solution, wash the absorbent cotton 5-8 times to obtain a clear liquid in a glass conical flask, continue heating and concentrate the volume to 10-15mL; add sulfuric acid solution and sodium tungstate solution, adjust the color to dark blue with titanium trichloride solution, then adjust to colorless with potassium dichromate solution (1 / 6K2Cr2O7), and adjust the solution volume to 80-100mL with water; after cooling to room temperature, add phosphoric acid, sulfuric acid solution, and sodium diphenylamine sulfonate solution, and add potassium dichromate solution (1 / 6K2Cr2O7) dropwise until a stable purple color appears;

[0030] Among them, the ratio of hydrochloric acid volume to m3 is (20~40)mL:(0.2~2.0)g; the ratio of sulfuric acid volume (1:3~8) added each time to m3 is (10~40)mL:(0.2~2.0)g; the ratio of potassium dichromate concentration to m3 is (0.0500~0.2000)mol / L:(0.2~2.0)g.

[0031] wFe in sample A″0 after magnetic attraction 合2 Determination of content:

[0032] Weigh the A″0 sample (recorded as m4) and place it in a glass conical flask. Add potassium fluoride solution, sodium bicarbonate, and hydrochloric acid with a density of ρ1.19 g / mL. Cover the crucible and heat at 280-320°C to dissolve. Concentrate the crucible to 10-15 mL. Remove and cool for 5-10 minutes. Use a filtration device with a gasket and wet absorbent cotton to filter out a large amount of free carbon in the solution. Wash the absorbent cotton 5-8 times to obtain a clear liquid in a glass conical flask. Add phosphoric acid, sulfuric acid solution, and sodium diphenylamine sulfonate solution. Add potassium dichromate solution (1 / 6K2Cr2O7) dropwise until it turns a stable purple color.

[0033] Among them, the ratio of hydrochloric acid volume to m4 is (20~30)mL:(0.2~2.0)g; the ratio of sulfuric acid volume (1:2~5) to m4 is (5~20)mL:(0.2~2.0)g; the ratio of potassium dichromate concentration to m4 is (0.0500~0.2000)mol / L:(0.2~2.0)g.

[0034] wFe in sample A″0 after magnetic attraction 合3 Determination of content:

[0035] Weigh the A″0 sample, record the mass as m5, place it in a dry glass conical flask, add ferric chloride solution, cover with a rubber stopper, and re-oscillate on an oscillator at 260-300 rpm for 40-60 minutes, then remove it, add potassium fluoride solution, sodium bicarbonate, and hydrochloric acid with a density of ρ1.19 g / mL, cover it in a porcelain crucible, heat at 280-320°C to dissolve, and concentrate the volume to 15 mL; remove it, cool it for 5-10 minutes, and then use a suction filtration device with a gasket and wet absorbent cotton to remove a large amount of free carbon in the solution by suction filtration. Wash the absorbent cotton 5-8 times to obtain a clear liquid, place it in a glass conical flask, add phosphoric acid, sulfuric acid solution, and sodium diphenylamine sulfonate solution, and add potassium dichromate solution (1 / 6K2Cr2O7) dropwise until it turns a stable purple color;

[0036] Among them, the ratio of hydrochloric acid volume to m5 is (20~40)mL:(0.2~1.0)g; the ratio of sulfuric acid volume (1:3~5) to m5 is (10~25)mL:(0.2~2.0)g; the ratio of potassium dichromate concentration to m5 is (0.0500~0.1500)mol / L:(0.2~1.0)g.

[0037] Compared with the prior art, the present invention has the following beneficial effects:

[0038] 1) The present invention adsorbs the iron phase sample A0 by magnet, and then calculates the content of magnetic metal iron in the magnetic material A1, and then calculates the content of each iron phase in the remaining sample, and finally uses normalization calculation to obtain the total iron (TFe), metallic iron (MFe), divalent iron (Fe 2+ ), ferric iron (Fe 3+ ) content.

[0039] 2) The present invention utilizes magnetism to enrich and adsorb most of the magnetic metallic iron in the iron-containing dust and mud, and adopts magnet enrichment to eliminate the influence of a large amount of free carbon on the determination of magnetic metallic iron, thereby realizing rapid determination of magnetic metallic iron and having small fluctuation in the results of metallic iron content.

[0040] 3) The present invention mixes the remaining sample A'0 with anhydrous sodium carbonate in a certain proportion, and dilutes the free carbon and trivalent iron (Fe) in the remaining sample A'0 in equal proportion per unit mass. 3+) and metallic iron (MFe) content, can effectively reduce the influence of free carbon on the color of stannous chloride solution. Because the hydrogen ions generated by the reaction of high content of metallic iron (MFe) with hydrochloric acid can reduce Fe 3+ ions, leading to the determination of Fe 2+ The present invention first magnetically removes a large amount of metallic iron to ensure that the metallic iron content of the remaining sample A'0 is at a low level, and at the same time uses anhydrous sodium carbonate to dilute the sample in equal proportion to further reduce the Fe content in the measured sample. 3+ and metallic iron content, thereby eliminating hydrogen ions to Fe 3+ ions, ensuring that the coexistence of metallic iron and trivalent iron does not affect Fe 2+ The analysis results have an impact.

[0041] 4) The present invention uses a suction filtration device and wet absorbent cotton to remove free carbon in the solution, further ensuring the accuracy of measuring the iron phase content. DETAILED DESCRIPTION

[0042] The specific embodiments of the present invention are further described below:

[0043] Example 1

[0044] A method for determining the iron phase content in iron-containing dust and mud comprises the following steps:

[0045] Step 1: Prepare an iron-containing dust mud sample, wherein the iron-containing dust mud sample has a total iron (TFe) mass fraction of 30-80%, a metallic iron (MFe) mass fraction of 5.0-70%, and a divalent iron (Fe 2+ ) mass fraction 0.3~40%, trivalent iron (Fe 3+ ) mass fraction of 0.2-15%; after ball milling the iron-containing dust, remove the undersize material with a particle size of ≤0.6 mm; quarter the undersize material once and ball mill it to a particle size of ≤0.18 mm; quarter the undersize material twice and ball mill it to a particle size of ≤0.10 mm; quarter the undersize material three times and ball mill it to a particle size of ≤0.075 mm; mix the undersize material after the third ball milling for 150 seconds to obtain an iron phase sample. The weight of the iron phase sample is controlled to be 300 g.

[0046] Step 2: Weigh the iron phase sample A0, m0 is 10.0000g, and place the iron phase sample A0 at 150cm 3 (bottom area 150cm 2) container, put a circular magnet with a magnetic force of 1.2 Tesla in a self-sealing bag, and place it close to sample A0 for adsorption. The adsorbed magnetic material is collected in the sample bag; the remaining sample in the container is stirred and then adsorbed for the second time. This operation is repeated 3 times. The magnetic material finally collected in the sample bag is fully mixed to obtain magnetic material A1 with a mass m1 of 3.5283 g. The sample A′0 finally remaining in the container has a mass m′0 of 6.4717 g.

[0047] Detection of wMFe in magnetic material A1 by potassium dichromate method 磁 Content, the steps are as follows:

[0048] Weigh 1.0000g of magnetic material A1, m2, and place it in a 300mL glass conical flask. Add 60mL of hydrochloric acid with a density of 1.19g / mL; heat at 280℃ to dissolve, add 50g / L stannous chloride solution until the color turns light yellow, and concentrate the volume to 15mL; then wait for 1 to 2 minutes and add 40mL of sulfuric acid solution (1:9) (referring to 1 volume of concentrated sulfuric acid and 9 volumes of deionized water mixed), add 15 drops of 10g / L sodium tungstate solution, and use titanium trichloride solution (1:1) (referring to 1 volume of concentrated sulfuric acid and 9 volumes of deionized water mixed) to make the solution uniformly distributed. 1 volume of titanium trichloride solution mixed with 1 volume of deionized water) until a stable dark blue color appears. Then, add 0.0500 mol / L potassium dichromate solution (1 / 6 K2Cr2O7) dropwise until the blue color of the solution completely fades. Add water to adjust the solution volume to 100 mL. After cooling to room temperature, add 5 mL of 1.70 g / mL phosphoric acid and 5 mL of sulfuric acid solution (1:2). Add 4 drops of 15 g / L sodium diphenylamine sulfonate solution. Add 0.5000 mol / L potassium dichromate solution dropwise until a stable purple color appears. Note the volume V1 = 35.78 mL.

[0049] The reagent blank V0 was obtained by adding 5.0 mL of ferrous sulfate 0.1000 mol / L twice and titrating with 0.0500 mol / L potassium dichromate (1 / 6K2Cr2O7), and the determination yielded V0 = 0.05 mL;

[0050] MFe 磁 Content calculation:

[0051]

[0052] Where: V1 is the volume of potassium dichromate consumed, mL;

[0053] C1—concentration of potassium dichromate solution (1 / 6K2Cr2O7) used to produce a stable purple color, mol / L;

[0054] m2—sample weight of this experiment, g;

[0055] V0—the volume of potassium dichromate consumed in the reagent blank, mL;

[0056] 55.85—Molar mass of Fe, g / moL;

[0057] wMFe 磁 —Metallic iron MFe 磁 content.

[0058] Step 3: Mix the remaining sample A'0 with anhydrous sodium carbonate in a mass fraction ratio of 1:5, and record the ratio coefficient of the mass of anhydrous sodium carbonate to the mass fraction of the remaining sample A'0 as k=5. The fully ground and mixed sample is recorded as A"0; weigh a certain amount of mixed sample from sample A"0, and use potassium dichromate method to detect wFe in the weighed mixed sample 合1 、wFe 合2 , and wFe 合3 content;

[0059] wFe in sample A″0 after magnetic attraction 合1 Content detection:

[0060] Weigh 0.2000 g of A″0 sample (m3) in a 300 mL glass conical flask, add 20 mL of 1.19 g / mL hydrochloric acid and 5 mL of 10 g / L potassium fluoride solution; heat to 300°C to dissolve, and concentrate to 10 mL; add 20 g / L stannous chloride solution dropwise until the color turns light yellow.

[0061] After cooling for 5 minutes, remove the solution and filter it using a filtration device with a gasket and wet cotton wool to remove the large amount of free carbon in the solution. The wet cotton wool needs to be compacted to a thickness of 3 cm. Wash the cotton wool five times to obtain a clear liquid in a 300 mL glass conical flask and continue heating to concentrate the volume to 10 mL.

[0062] Remove and add 5mL of sulfuric acid solution (1:3); add 10 drops of 10g / L sodium tungstate solution, adjust with titanium trichloride solution (1:2) until dark blue appears, then adjust with 0.0500mol / L potassium dichromate solution (1 / 6K2Cr2O7) until colorless, and add water to adjust the solution volume to 100mL; after cooling to room temperature, add 2mL of 1.70g / mL phosphoric acid, 5mL of sulfuric acid solution (1:2), 4 drops of 10g / L sodium diphenylamine sulfonate solution, and 0.0500mol / L potassium dichromate solution (1 / 6K2Cr2O7) until a stable purple color appears, and record the volume V2 = 5.82mL;

[0063]

[0064] Where: V2 is the volume of potassium dichromate consumed, mL;

[0065] C2—concentration of potassium dichromate solution (1 / 6K2Cr2O7) used to produce a stable purple color, mol / L;

[0066] m3—sample weight in this experiment, g;

[0067] V0—the volume of potassium dichromate consumed in the reagent blank, mL;

[0068] 55.85—Molar mass of Fe, g / moL;

[0069] wxya 合1 —∑MFe′+Fe 3+ +Fe 2+ content.

[0070] wFe in sample A″0 after magnetic attraction 合2 Content detection:

[0071] Weigh 0.2000 g of A″0 sample (m4) in a 300 mL glass conical flask, add 5 mL of 5 g / L potassium fluoride solution, 1.0 g of sodium bicarbonate, and 20 mL of 1.19 g / mL hydrochloric acid. Cover with a 30 mL porcelain crucible, heat at 320°C to dissolve, and concentrate to 10 mL.

[0072] Remove the container and cool for 5 minutes. Filter the solution using a gasketed filtration device and wet cotton wool to remove any free carbon. Compact the cotton wool to a thickness of 3 cm. Wash the cotton wool six times to obtain a clear solution in a 500 mL glass conical flask.

[0073] Add 2 mL of 1.70 g / mL phosphoric acid, 5 mL of sulfuric acid solution (1:2), 4 drops of 10 g / L sodium diphenylamine sulfonate solution, and 0.0500 mol / L potassium dichromate solution (1 / 6K2Cr2O7) until the solution turns a stable purple. Note the volume V3 = 4.52 mL.

[0074]

[0075] Where: V3—the volume of potassium dichromate consumed, mL;

[0076] C3—concentration of potassium dichromate solution (1 / 6K2Cr2O7) used to make a stable purple color, mol / L;

[0077] m4—sample weight in this experiment, g;

[0078] V0—the volume of potassium dichromate consumed in the reagent blank, mL;

[0079] 55.85—Molar mass of Fe, g / moL;

[0080] wxya 合2 —∑Fe 2+ +MFe′ content.

[0081] wFe in sample A″0 after magnetic attraction 合3 Content detection:

[0082] Weigh 0.2000 g of A″0 sample (m5) and place it in a 300 mL dry glass conical flask. Add 40 mL of 120 g / L ferric chloride solution, cover with a rubber stopper, and shake on an oscillator at 260 rpm for 40 min. Add 10 mL of 5 g / L potassium fluoride solution and 2.0 g of sodium bicarbonate. Add 20 mL of 1.19 g / mL hydrochloric acid, cover with a 30 mL porcelain crucible, heat at 320°C to dissolve, and concentrate to 15 mL.

[0083] After cooling for 5 minutes, remove the container and filter using a gasketed filtration device and wet cotton wool to remove a large amount of free carbon from the solution. The wet cotton wool needs to be compacted to a thickness of 3 cm. Wash the cotton wool six times to obtain a clear liquid in a 500 mL glass conical flask. Add 10 mL of 1.70 g / mL phosphoric acid and 10 mL of sulfuric acid solution (1:3), add 4 drops of 10 g / L sodium diphenylamine sulfonate solution, and add 0.0500 mol / L potassium dichromate solution (1 / 6K2Cr2O7) until it turns a stable purple color. Record the volume V4 = 5.00 mL.

[0084]

[0085] Where: V4 is the volume of potassium dichromate consumed, mL;

[0086] C4—concentration of potassium dichromate solution (1 / 6K2Cr2O7) used to make a stable purple color, mol / L;

[0087] m5—sample weight in this experiment, g;

[0088] V0—the volume of potassium dichromate consumed in the reagent blank, mL;

[0089] 55.85—Molar mass of Fe, g / moL;

[0090] wxya 合3 —ΣFe 2+ +3MFe′ content.

[0091] Step 4: Normalize the content results obtained in steps 2 and 3, and finally obtain the content of total iron (TFe), metallic iron (MFe), divalent iron (Fe 2+ ), ferric iron (Fe 3+ ) content.

[0092] The iron phase content in sample A0 is calculated as follows:

[0093]

[0094] In the above formula:

[0095] m0—mass of iron phase sample A0;

[0096] m1—mass of iron phase sample A1;

[0097] m′0—mass of the iron phase sample A′0;

[0098] w MFe —The content of metallic iron in the iron phase sample A0;

[0099] w Fe 2+ —The content of ferrous iron in the iron phase sample A0;

[0100] w Fe 3+ —The content of ferric iron in the iron phase sample A0;

[0101] w TFe —Total iron content in iron phase sample A0.

[0102] Example 2

[0103] A method for determining the iron phase content in iron-containing dust and mud comprises the following steps:

[0104] Step 1: Prepare an iron-containing dust mud sample, wherein the iron-containing dust mud sample has a total iron (TFe) mass fraction of 30-80%, a metallic iron (MFe) mass fraction of 5.0-70%, and a divalent iron (Fe 2+ ) mass fraction 0.3~40%, trivalent iron (Fe 3+ ) mass fraction of 0.2-15%; after ball milling the iron-containing dust, remove the undersize material with a particle size of ≤0.6 mm; quarter the undersize material once and ball mill it to a particle size of ≤0.18 mm; quarter the undersize material twice and ball mill it to a particle size of ≤0.10 mm; quarter the undersize material three times and ball mill it to a particle size of ≤0.075 mm; mix the undersize material after the third ball milling for 400 seconds to obtain an iron phase sample. The weight of the iron phase sample is controlled to be 600 g.

[0105] Step 2: Weigh the iron phase sample A0, m0 is 15.0000g, place the iron phase sample A0 at 400cm 3 (Bottom area 200cm 2) container, put a circular magnet with a magnetic force of 1.5 Tesla in a self-sealing bag, and place it close to sample A0 for adsorption. The adsorbed magnetic material is collected in the sample bag; the remaining sample in the container is stirred and then adsorbed for the second time. This operation is repeated 5 times. The magnetic material finally collected in the sample bag is fully mixed to obtain magnetic material A1, m1 is 8.1524 g, and the sample A′0 finally remaining in the container, m′0 is 6.8476 g.

[0106] Detection of metallic iron MFe in magnetic material A1 using potassium dichromate method 磁 Content, the steps are as follows:

[0107] Weigh 0.2500g of magnetic material A1 and m2, place them in a 300mL glass conical flask, add 25mL of hydrochloric acid with a density of 1.19g / mL; heat to 320℃ to dissolve, add 20g / L stannous chloride solution until the color turns light yellow, and concentrate the volume to 10mL; then wait for 1 to 2 minutes and add 10mL of sulfuric acid solution (1:3), add 10 drops of 15g / L sodium tungstate solution, and adjust with titanium trichloride solution (1:4) until a stable After the solution turns dark blue, add 0.0500mol / L potassium dichromate solution (1 / 6K2Cr2O7) until the blue color of the solution completely fades, and then add water to adjust the solution volume to 80mL; after cooling to room temperature, add 10mL of 1.70g / mL phosphoric acid, 10mL of sulfuric acid solution (1:3), add 4 drops of 10g / L sodium diphenylamine sulfonate solution, and add 0.15000mol / L potassium dichromate solution until the solution turns stable purple, and record the volume V1 = 29.35mL;

[0108] The reagent blank V0 is obtained by adding 15 mL of ferrous sulfate 0.1000 mol / L twice and titrating with 0.0500 mol / L potassium dichromate (1 / 6K2Cr2O7), and the determination results in V0 = 0.05 mL;

[0109] MFe 磁 Content calculation:

[0110]

[0111] Where: V1 is the volume of potassium dichromate consumed, mL;

[0112] C1—concentration of potassium dichromate solution (1 / 6K2Cr2O7) used to produce a stable purple color, mol / L;

[0113] m2—sample weight of this experiment, g;

[0114] V0—the volume of potassium dichromate consumed in the reagent blank, mL;

[0115] 55.85—Molar mass of Fe, g / moL;

[0116] wMFe 磁 —Metallic iron MFe 磁 content.

[0117] Step 3: Mix the remaining sample A'0 with anhydrous sodium carbonate in a mass fraction ratio of 1:2. The mass fraction ratio of anhydrous sodium carbonate to the remaining sample A'0 is recorded as k=2. The fully ground and mixed sample is recorded as A"0. Weigh a certain amount of mixed sample from sample A"0 and use potassium dichromate method to detect wFe in the mixed sample. 合1 、wFe 合2 , and wFe 合3 content;

[0118] wFe in sample A″0 after magnetic attraction 合1 Content detection:

[0119] Weigh 0.5000 g of A″0 sample (m3) in a 300 mL glass conical flask, add 25 mL of 1.19 g / mL hydrochloric acid and 8 mL of 10 g / L potassium fluoride solution; heat to 280°C to dissolve, and concentrate to 15 mL; add 30 g / L stannous chloride solution dropwise until the color turns light yellow.

[0120] After cooling to room temperature, remove the solution and use a filtration device with a gasket and wet cotton wool to remove a large amount of free carbon from the solution. The wet cotton wool needs to be compacted to a thickness of 6 cm. Wash the cotton wool five times to obtain a clear liquid in a 300 mL glass conical flask and continue heating to concentrate the volume to 15 mL.

[0121] Remove and add 30mL of sulfuric acid solution (1:8); add 5 drops of 15g / L sodium tungstate solution, adjust with titanium trichloride solution (1:2) until dark blue appears, then adjust with 0.0500mol / L potassium dichromate solution (1 / 6K2Cr2O7) until colorless, and add water to adjust the solution volume to 100mL; after cooling to room temperature, add 2mL of 1.70g / mL phosphoric acid, 5mL of sulfuric acid solution (1:3), add 4 drops of 10g / L sodium diphenylamine sulfonate solution, and add 0.1000mol / L potassium dichromate solution (1 / 6K2Cr2O7) until a stable purple color appears, and record the volume V2 = 11.42mL;

[0122]

[0123] Where: V2 is the volume of potassium dichromate consumed, mL;

[0124] C2—concentration of potassium dichromate solution (1 / 6K2Cr2O7) used to produce a stable purple color, mol / L;

[0125] m3—sample weight in this experiment, g;

[0126] V0—the volume of potassium dichromate consumed in the reagent blank, mL;

[0127] 55.85—Molar mass of Fe, g / moL;

[0128] wxya 合1 —ΣMFe′+Fe 3+ +Fe 2+ content.

[0129] wFe in sample A″0 after magnetic attraction 合2 Content detection:

[0130] Weigh 0.5000 g of A″0 sample (m4) in a 300 mL glass conical flask, add 8 mL of 10 g / L potassium fluoride solution, 1.5 g of sodium bicarbonate, and 25 mL of 1.19 g / mL hydrochloric acid. Cover with a 30 mL porcelain crucible, heat at 300°C to dissolve, and concentrate to 10 mL.

[0131] Remove the container and cool for 10 minutes. Filter the solution using a gasketed filtration device and wet cotton wool to remove any free carbon. Compact the cotton wool to a thickness of 6 cm. Wash the cotton wool five times to obtain a clear solution in a 500 mL glass conical flask.

[0132] Add 5 mL of 1.70 g / mL phosphoric acid, 15 mL of sulfuric acid solution (1:3), 4 drops of 10 g / L sodium diphenylamine sulfonate solution, and 0.0500 mol / L potassium dichromate solution (1 / 6 K2Cr2O7) until the solution turns a stable purple. Note the volume V3 = 20.41 mL.

[0133]

[0134] Where: V3—the volume of potassium dichromate consumed, mL;

[0135] C3—concentration of potassium dichromate solution (1 / 6K2Cr2O7) used to make a stable purple color, mol / L;

[0136] m4—sample weight in this experiment, g;

[0137] V0—the volume of potassium dichromate consumed in the reagent blank, mL;

[0138] 55.85—Molar mass of Fe, g / moL;

[0139] wxya 合2 —ΣFe 2++MFe′ content.

[0140] wFe in sample A″0 after magnetic attraction 合3 Content detection:

[0141] Weigh 0.5000 g of A″0 sample (m5) in a 300 mL dry conical glass flask, add 40 mL of 120 g / L ferric chloride solution, cover with a rubber stopper, and oscillate on an oscillator at 260 rpm for 60 min. Add 10 mL of 10 g / L potassium fluoride solution and 2.0 g of sodium bicarbonate, then add 30 mL of 1.19 g / mL hydrochloric acid. Cover with a 30 mL porcelain crucible, heat at 300°C to dissolve, and concentrate to 15 mL.

[0142] After cooling for 10 minutes, remove the container and filter using a gasketed filtration device and wet cotton wool to remove a large amount of free carbon from the solution. The wet cotton wool needs to be compacted to a thickness of 6 cm. Wash the cotton wool five times to obtain a clear liquid in a 500 mL glass conical flask. Add 12 mL of 1.70 g / mL phosphoric acid, 12 mL of sulfuric acid solution (1:4), and 4 drops of 10 g / L sodium diphenylamine sulfonate solution. Add 0.0500 mol / L potassium dichromate solution (1 / 6K2Cr2O7) until a stable purple color is formed. Record the volume V4 = 24.00 mL.

[0143]

[0144] Where: V4 is the volume of potassium dichromate consumed, mL;

[0145] C4—concentration of potassium dichromate solution (1 / 6K2Cr2O7) used to make a stable purple color, mol / L;

[0146] m5—sample weight in this experiment, g;

[0147] V0—the volume of potassium dichromate consumed in the reagent blank, mL;

[0148] 55.85—Molar mass of Fe, g / moL;

[0149] wxya 合3 —ΣFe 2+ +3MFe′ content.

[0150] Step 4: Normalize the content of each phase of the iron phase obtained in steps 2 and 3, and finally obtain the content of total iron (TFe), metallic iron (MFe), divalent iron (Fe 2+ ), ferric iron (Fe 3+ The iron phase content in sample A0 is calculated as follows:

[0151]

[0152] In the above formula:

[0153] m0—mass of iron phase sample A0;

[0154] m1—mass of magnetic material A1;

[0155] m′0—mass of the remaining sample A′0;

[0156] w MFe —The content of metallic iron in the iron phase sample A0;

[0157] w Fe 2+ —The content of ferrous iron in the iron phase sample A0;

[0158] w Fe 3+ —The content of ferric iron in the iron phase sample A0;

[0159] w TFe —Total iron content in iron phase sample A0.

[0160] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, and these simple modifications all fall within the scope of protection of the present invention. It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner unless there is any contradiction. In order to avoid unnecessary repetition, the present invention will no longer describe various possible combinations separately. In addition, the various different embodiments of the present invention can also be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A method for determining the iron phase content in iron-containing dust and mud, characterized in that: The steps include: Step 1: Prepare an iron-containing dust mud sample and ball-mill the iron-containing dust mud to obtain an iron phase sample; Step 2: Weigh the iron phase sample A0, place it in a container, use a magnet to adsorb the magnetic material in it, weigh the adsorbed magnetic material A1 and the remaining sample A'0 respectively, and use the potassium dichromate method to detect the magnetic metal iron content in the magnetic material A1. The magnetic metal iron content is recorded as wMFe 磁 ; Step 3: Mix the remaining sample A'0 with anhydrous sodium carbonate in a mass fraction ratio of 1:(2-5), the mass fraction ratio of anhydrous sodium carbonate to the remaining sample A'0 is recorded as k, and the sample after thorough grinding and mixing is recorded as A'0'; weigh the mixed samples from sample A'0', and use potassium dichromate method to detect wFe in the weighed mixed samples 合1 、wFe 合2 , and wFe 合3 Content; among them, wFe 合1 is the sum of the remaining metallic iron, ferric iron, and ferrous iron in the mixed sample, which is ∑MFe′+Fe 3+ +Fe 2+ ;wFe 合2 is the sum of the remaining metallic iron and divalent iron in the mixed sample, which is ∑Fe 2+ +MFe′;wFe 合3 is the sum of three times the residual metallic iron and divalent iron in the mixed sample, which is ∑Fe 2+ +3MFe′; Step 4: Normalize the content results obtained in steps 2 and 3, and finally obtain the content of total iron (TFe), metallic iron (MFe), divalent iron (Fe 2+ ), ferric iron (Fe 3+ ) content; The calculation formula is as follows: w F e 3+ = (wFe 合1 - wFe 合2 ) × (k + 1) × m′0 / m0…………Formula (3) w TFe =(wFe 合1 ×(k+1)×m′0+wMFe 磁 ×m1) / m0…………Formula (4) In the above formula: m0—mass of iron phase sample A0; m1—mass of magnetic material A1; m′0—mass of the remaining sample A′0; w MFe —The content of metallic iron in the iron phase sample A0; w Fe 2+ —The content of ferrous iron in the iron phase sample A0; w Fe 3+ —The content of ferric iron in the iron phase sample A0; w TFe —Total iron content in iron phase sample A0.

2. The method for determining the iron phase content in iron-containing dust and mud according to claim 1, characterized in that: In the step 1, an iron-containing dust mud sample is prepared, wherein the iron-containing dust mud sample has a total iron (TFe) mass fraction of 30-80%, a metallic iron (MFe) mass fraction of 5.0-70%, and a divalent iron (Fe 2+ ) mass fraction 0.3~40%, trivalent iron (Fe 3+ ) mass fraction of 0.2 to 15%; after ball milling the iron-containing dust, take out the undersize material with a particle size of ≤0.6 mm; quarter the undersize material once, ball mill it, and the discharge particle size is ≤0.18 mm; then quarter the undersize material twice, ball mill it, and the discharge particle size is ≤0.10 mm; quarter the undersize material three times, ball mill it, and the discharge particle size is ≤0.075 mm; mix the undersize material after the third ball milling, and after mixing for 150 to 400 seconds, obtain an iron phase sample, and the mass of the iron phase sample is controlled at 300 to 600 g.

3. The method for determining the iron phase content in iron-containing dust and mud according to claim 1, characterized in that: The mass m0 of the iron phase sample A0 weighed is 10.0000~20.0000g. The iron phase sample A0 is placed at 150~400cm 3 In the container, a round or square magnet with a magnetic force greater than 1 Tesla is placed in a self-sealing bag and placed close to sample A0 for adsorption. The adsorbed magnetic material is collected in the sample bag; the remaining sample in the container is stirred and then adsorbed for the second time. This operation is repeated 3 to 5 times. The magnetic material finally collected in the sample bag is fully mixed to obtain magnetic material A1 and the remaining sample A′0 in the container, and they are weighed separately.

4. The method for determining the iron phase content in iron-containing dust and mud according to claim 1, characterized in that: The potassium dichromate method was used to detect wMFe in magnetic material A1. 磁 The specific steps are as follows: Weigh magnetic substance A1, record its mass as m2, place it in a glass conical flask, add hydrochloric acid with a density of ρ1.19 g / mL; heat at 280-320°C to dissolve, add stannous chloride solution dropwise until the color turns light yellow, and concentrate the volume to 10-15 mL; then wait for 1-2 minutes before adding sulfuric acid solution, add sodium tungstate solution, and adjust the color with titanium trichloride solution until a stable dark blue appears. Then, add potassium dichromate solution (1 / 6K2Cr2O7) dropwise until the blue color of the solution completely fades, stop, and add water to adjust the solution volume to 80-100 mL; after cooling to room temperature, add phosphoric acid, sulfuric acid solution, and sodium diphenylamine sulfonate solution, and add potassium dichromate solution dropwise until a stable purple color appears. Among them, the ratio of hydrochloric acid volume to m2 is (20~60)mL:(0.2~3.0)g; the ratio of sulfuric acid volume (1:2~9) added each time to m2 is (5~60)mL:(0.2~3)g; the ratio of potassium dichromate concentration to m2 is (0.0500~0.5000)mol / L; (0.2~3)g.

5. The method for determining the iron phase content in iron-containing dust and mud according to claim 1, characterized in that: wFe in sample A″0 after magnetic attraction 合1 Determination of content: Weigh the A″0 sample, record the mass as m3, place it in a glass conical flask, add hydrochloric acid with a density of ρ1.19g / mL and potassium fluoride solution; heat at 280-320℃ to dissolve, and concentrate the volume to 10-15mL; add stannous chloride solution dropwise until the color turns light yellow; remove and cool for 5-10min, use a suction filtration device with a gasket and wet absorbent cotton to filter out a large amount of free carbon in the solution, wash the absorbent cotton 5-8 times to obtain a clear liquid in a glass conical flask, continue heating and concentrate the volume to 10-15mL; add sulfuric acid solution and sodium tungstate solution, adjust the color to dark blue with titanium trichloride solution, then adjust to colorless with potassium dichromate solution (1 / 6K2Cr2O7), and adjust the solution volume to 80-100mL with water; after cooling to room temperature, add phosphoric acid, sulfuric acid solution, and sodium diphenylamine sulfonate solution, and add potassium dichromate solution (1 / 6K2Cr2O7) dropwise until a stable purple color appears; Among them, the ratio of hydrochloric acid volume to m3 is (20~40)mL:(0.2~2.0)g; the ratio of sulfuric acid volume (1:3~8) added each time to m3 is (10~40)mL:(0.2~2.0)g; the ratio of potassium dichromate concentration to m3 is (0.0500~0.2000)mol / L:(0.2~2.0)g.

6. The method for determining the iron phase content in iron-containing dust and mud according to claim 1, characterized in that: wFe in sample A″0 after magnetic attraction 合2 Determination of content: Weigh the A″0 sample (recorded as m4) and place it in a glass conical flask. Add potassium fluoride solution, sodium bicarbonate, and hydrochloric acid with a density of ρ1.19 g / mL. Cover the crucible and heat at 280-320°C to dissolve. Concentrate the crucible to 10-15 mL. Remove and cool for 5-10 minutes. Use a filtration device with a gasket and wet absorbent cotton to filter out a large amount of free carbon in the solution. Wash the absorbent cotton 5-8 times to obtain a clear liquid in a glass conical flask. Add phosphoric acid, sulfuric acid solution, and sodium diphenylamine sulfonate solution. Add potassium dichromate solution (1 / 6K2Cr2O7) dropwise until it turns a stable purple color. Among them, the ratio of hydrochloric acid volume to m4 is (20~30)mL:(0.2~2.0)g; the ratio of sulfuric acid volume (1:2~5) to m4 is (5~20)mL:(0.2~2.0)g; the ratio of potassium dichromate concentration to m4 is (0.0500~0.2000)mol / L:(0.2~2.0)g.

7. The method for determining the iron phase content in iron-containing dust and mud according to claim 1, characterized in that: wFe in sample A″0 after magnetic attraction 合3 Determination of content: Weigh the A″0 sample, record the mass as m5, place it in a dry glass conical flask, add ferric chloride solution, cover with a rubber stopper, and re-oscillate on an oscillator at 260-300 rpm for 40-60 minutes, then remove it, add potassium fluoride solution, sodium bicarbonate, and hydrochloric acid with a density of ρ1.19 g / mL, cover it in a porcelain crucible, heat at 280-320°C to dissolve, and concentrate the volume to 15 mL; remove it, cool it for 5-10 minutes, and then use a suction filtration device with a gasket and wet absorbent cotton to remove a large amount of free carbon in the solution by suction filtration. Wash the absorbent cotton 5-8 times to obtain a clear liquid, place it in a glass conical flask, add phosphoric acid, sulfuric acid solution, and sodium diphenylamine sulfonate solution, and add potassium dichromate solution (1 / 6K2Cr2O7) dropwise until it turns a stable purple color; Among them, the ratio of hydrochloric acid volume to m5 is (20~40)mL:(0.2~1.0)g; the ratio of sulfuric acid volume (1:3~5) to m5 is (10~25)mL:(0.2~2.0)g; the ratio of potassium dichromate concentration to m5 is (0.0500~0.1500)mol / L:(0.2~1.0)g.

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