Method for phase analysis of iron in ore

Abstract

The application discloses a method for analyzing phases of iron in ores, and belongs to the technical field of mineral analysis. The method comprises the following steps: after magnetic separation of an ore sample, performing iron valence state analysis on a magnetic product, and distinguishing a magnetic iron phase, a pseudo hematite phase and a magnetic intergrowth phase based on the deviation degree of the ratio of divalent iron to trivalent iron from the theoretical ratio of magnetite; sequentially performing iron carbonate phase selective leaching-oxidation post-treatment, hematite-limonite phase reduction-inhibition synergistic selective dissolution, iron sulfide phase liquid phase complexation-solid phase charring step-by-step extraction and iron silicate phase alkali fusion digestion on a non-magnetic product; and finally, performing plasma atomic emission spectrometry on each phase to-be-measured solution and total iron digestion liquid, and calculating the iron content of each phase. The application solves the key problems in traditional iron phase analysis, such as incomplete classification of magnetic iron, poor selectivity of non-magnetic phase and insufficient wide use.

Description

Technical Field

[0001] This invention relates to the field of mineral analysis technology, and specifically to a method for phase analysis of iron in ores. Background Technology

[0002] Chemical phase analysis is a relatively new branch of analytical chemistry, initially applied in industrial fields such as mineral processing engineering and metallurgy, geological prospecting, process mineralogy, and beneficiation experimental research. In modern times, the application scope of chemical phase analysis has expanded to disciplines closely related to people's daily lives, including the environment, industry, food, and traditional Chinese medicine, and significant progress has been made in all these areas.

[0003] Iron is one of the most widely distributed elements in the Earth's crust, with an average content of approximately 5.63%. As a fundamental raw material for the steel industry, the suitability and smelting value of iron ore depend not only on its total iron content but also on the specific phases in which it is found. Geological research and mineral processing experiments typically require systematic phase analysis of iron ore. The main phases determined include magnetic iron, pseudomorphic hematite, magnetic pig iron, iron carbonate, goethite, iron sulfide, and iron silicate. Iron deposits of different origins, such as sedimentary metamorphic, skarn, volcanic, or weathering-leaching deposits, exhibit vastly different mineral assemblages, often showing complex situations such as the coexistence of hematite and pseudomorphic hematite, and goethite in a gel-like state adsorbing other components. Furthermore, some gangues containing iron but not actually iron minerals have chemically very similar properties to iron minerals, posing significant technical challenges to selective separation. Therefore, establishing a universal and scientifically classified method for the chemical phase analysis of iron ore is particularly important.

[0004] In iron phase analysis, the selection of leaching conditions is the core and challenge that determines the success or failure of the analysis. Establishing specific dissolution conditions for each phase requires rigorous optimization of many factors, including solvent composition and concentration, leaching temperature, solid-liquid ratio, leaching time, stirring method, side reaction estimation and suppression measures, and the selection of leaching promoters and inhibitors. These factors interact with each other, and improper control can easily lead to cross-contamination between mineral phases, resulting in severely distorted measurement results. However, the current research foundation for iron phase analysis is very weak, with very few systematic literatures available, and existing methods generally have many shortcomings. First, the phase classification system is inconsistent and often incomplete. Many procedures only classify five phases: magnetic iron, iron carbonate, hematite, iron sulfide, and iron silicate, lacking specific determination schemes for pseudomorphous hematite and magnetic pig iron, which are equally important in the process. The problem of incomplete classification is prominent. Secondly, cross-phase phenomena are very common. For example, when siderite is leached for a short time with low-concentration hydrochloric acid, some fine-grained hematite will dissolve simultaneously, leading to an overestimation of iron carbonate. When ferrosilicon is treated with hydrofluoric acid, microcrystalline hematite and altered magnetite are also difficult to avoid. Furthermore, most existing methods follow the old manual operation mode, relying on potassium dichromate titration or spectrophotometry, which are lengthy, labor-intensive, and consume a lot of reagents, far from meeting the requirements of large-scale rapid detection. More importantly, these traditional methods have failed to be deeply integrated with the rapidly developing modern testing technologies in recent years, resulting in significant deficiencies in the selectivity, accuracy, efficiency, and universality of iron phase analysis methods, seriously restricting the refined evaluation of complex iron ore resources and the intelligent development of beneficiation and smelting processes.

[0005] In view of this, it is necessary to study a phase analysis method for iron in ore to solve the above-mentioned technical problems. Summary of the Invention

[0006] In view of the technical problems existing in the background art, the present invention provides a method for phase analysis of iron in ores. This method effectively solves a series of technical problems such as incomplete iron phase classification, poor applicability, and outdated analytical methods.

[0007] This invention provides a method for phase analysis of iron in ore, comprising the following steps: S1, Magnetic separation: The ore sample is subjected to wet magnetic separation to obtain magnetic and non-magnetic products; S2, Magnetic phase and valence state identification: The magnetic product is subjected to iron valence state analysis. Based on the content ratio of divalent iron to trivalent iron and the degree of deviation from the theoretical valence state ratio of magnetite, at least one of magnetic iron phase, pseudomorphic hematite phase, and magnetic intergrowth phase is distinguished. S3, Stepwise extraction of non-magnetic phases: The non-magnetic products are sequentially subjected to stepwise chemical extraction based on a selective dissolution mechanism to obtain test solutions of ferric carbonate phase, hematite phase, ferric sulfide phase and ferrosilicon phase respectively; wherein, the selective dissolution of the hematite phase is carried out in a system containing a reducing agent and a co-solution inhibitor; S4, Spectral Measurement and Calculation: Perform plasma atomic emission spectroscopy on the test solutions of each phase obtained in steps S2 and S3, as well as the total iron digest of the ore sample, and calculate the iron content of each phase.

[0008] As a further improvement of the present invention, the extraction process of the iron carbonate phase in step S3 is as follows: The non-magnetic product is mixed with the first extractant and heated to selectively dissolve the ferric carbonate phase; The extract was subjected to oxidative post-treatment, followed by acid digestion to obtain the ferric carbonate phase test solution; The first extractant is an acetic acid solution; the oxidative post-treatment adopts a composite oxidation system of hydrogen peroxide and hypochlorite, with a volume ratio of (1.5-2.5):1.

[0009] As a further improvement of the present invention, the extraction process of the hematite phase in step S3 is as follows: The residue after ferric carbonate extraction is mixed with a composite leaching system containing a second leaching agent, a reducing agent, and a co-solution inhibitor and heated to allow the hematite phase to selectively dissolve under conditions that inhibit the dissolution of other iron phases. The reducing agent is used to reduce ferric iron to a more soluble divalent state, and the co-solution inhibitor is used to inhibit the co-solubility of ferric silicate and / or ferric sulfide. The reducing agent comprises a complex system of sulfite and ascorbic acid, with a mass concentration ratio of 1:2; the co-solution inhibitor comprises thiocyanate and / or a nonpolar organic solvent. The thiocyanate is a potassium thiocyanate solution with a concentration of 1.5-2.5 g / L; the non-polar organic solvent is n-hexane with a dosage of 0.4-0.6 mL / L. The second extractant is a mixed solution of stannous chloride and hydrochloric acid.

[0010] As a further improvement of the present invention, in step S3, the extraction of the iron sulfide phase adopts a stepwise extraction method, including: First liquid phase extraction: The residue after the extraction of hematite is successively contacted with the third and fourth leaching agents by shaking to partially dissolve the iron sulfide phase and obtain the first extract; Second solid-phase digestion: The filter residue after the first liquid phase extraction is subjected to high-temperature ashing and then acid digestion to obtain the second digestion solution; The first extract and the second digest were combined to obtain the iron sulfide phase test solution. The third extractant is saturated bromine water; the fourth extractant is a thiosulfate solution with a concentration of 1.5-2.5 g / L; the high-temperature ashing temperature is 650-750℃; and the acid digestion uses an aqua regia system.

[0011] As a further improvement of the present invention, in step S3, the digestion process of the iron silicate phase is as follows: The final residue after iron sulfide extraction is subjected to alkali melting treatment to completely convert the iron silicate phase into a soluble state. After acid leaching, the iron silicate phase test solution is obtained. The alkali melting process uses a mixture of carbonate and peroxide flux, with a melting temperature of 650-750℃.

[0012] As a further improvement of the present invention, in step S2, the iron valence state analysis includes: The magnetic product is placed in a mixed medium containing polyols and halogen oxidants and subjected to oscillation treatment to selectively oxidize / reduce the surface of the magnetic minerals. After acid digestion, the total iron content and the content of ferrous iron were determined, and the content of ferric iron was obtained by subtraction. The measured ratio of ferrous iron to ferric iron was compared with the theoretical ratio of magnetite. When ferric iron was in relative excess, it was determined that a pseudo-hematite phase existed, and when ferrous iron was in relative excess, it was determined that a magnetic intergrowth phase existed.

[0013] As a further improvement of the present invention, the comparison includes: When ferric iron is in excess, the content of magnetic iron phase is calculated by multiplying the content of ferrous iron by the theoretical stoichiometric coefficients of ferric iron and ferrous iron. The difference between the total amount of magnetically separated iron and the content of magnetic iron phase is the content of pseudo-hematite phase iron. When ferrous iron is in excess, the iron content of the magnetic iron phase is calculated by multiplying the ferric iron content by the theoretical stoichiometric coefficients of ferrous and ferric iron. The difference between the total amount of magnetically separated iron and the iron content of the magnetic iron phase is the iron content of the magnetic intergrowth phase.

[0014] As a further improvement of the present invention, the separation process of magnetic components in the ore sample in step S1 is as follows: A single magnetic separation enrichment was performed at the bottom of a container holding a mixture of ore sample and water using a large first magnet. A second micromagnet placed inside a sealed tube is immersed in the mixed solution to perform secondary magnetic separation and enrichment of suspended or weakly magnetic particles.

[0015] As a further improvement of the present invention, step S4 also includes total iron verification, the process of which is as follows: the ore sample is heated and digested using a quaternary system of hydrochloric acid-nitric acid-hydrofluoric acid-perchloric acid, and the total iron content is obtained by plasma atomic emission spectrometry, which is used for normalization correction of the results of each phase.

[0016] As a further improvement of the present invention, in step S4, the iron content of each phase is calculated according to the following formula: ; In the formula: W(Fe) is the mass fraction of iron in each phase, expressed as a percentage. C represents the iron concentration obtained from the standard curve, in μg / mL; C0 is the concentration of the blank obtained from the standard curve, in μg / mL; V is the final volume of the sample, in mL; d represents the dilution factor of the sample; m represents the mass of the sample, expressed in grams.

[0017] Beneficial effects: The method provided by this invention scientifically selects the leaching agents for each phase based on the various forms of iron that may exist in the ore, ensuring that the leaching agent of the previous phase does not leach iron from the next phase, thereby achieving accurate determination of each phase. A combined magnetic separation using large and small magnets ensures complete removal of magnetic iron. Magnetic iron is thoroughly dissolved using a system of ethylene glycol, liquid bromine, and a mixed acid, and a method for calculating magnetic iron content is provided to ensure accurate calculation of the iron content in the magnetic iron. A solution of hydrogen peroxide and sodium hypochlorite in a 2:1 volume ratio is used as a decomposing agent for excess acetic acid. A mixed solution of sodium sulfite and ascorbic acid in a 1:2 volume ratio is added to ensure the effective components of the second leaching agent, reduce its dosage, and avoid interference with subsequent ICP determination. Inhibitors KSCN and n-hexane are added to prevent the dissolution of iron sulfide, thus avoiding influence on the determination results of the reddish-brown iron and iron sulfide phases. Sodium thiosulfate is used to further dissolve iron sulfide and simultaneously eliminate excess saturated bromine water. In addition, all reactions requiring heating are heated by electric hot plates, which is simple to operate and suitable for batch processing.

[0018] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0019] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the present invention will be briefly described below. Obviously, the drawings described below are merely some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0020] Figure 1This is a schematic flowchart of the phase analysis method for iron in ore provided in an embodiment of the present invention.

[0021] Figure 2 This is the measurement and operation interface for the standard curve provided in the embodiments of the present invention.

[0022] Figure 3 An instrument for measuring the iron phase concentration provided in an embodiment of the present invention.

[0023] Figure 4 The images shown are actual photographs of the test solutions for each phase provided in the embodiments of the present invention. Detailed Implementation

[0024] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the technical solution of the present invention and are therefore intended to limit the scope of protection of the present invention.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the invention, are intended to cover non-exclusive inclusion.

[0026] In the description of the embodiments of this invention, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this invention, "multiple" means two or more, unless otherwise explicitly defined.

[0027] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0028] In the description of the embodiments of this invention, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0029] In the description of the embodiments of the present invention, the term "multiple" refers to two or more (including two), similarly, "multiple groups" refers to two or more (including two groups), and "multiple pieces" refers to two or more (including two pieces).

[0030] To address the current scarcity of literature on iron phase analysis, and the fact that existing literature suffers from issues such as phase cross-classification, incomplete classification, lack of universality and broad applicability, outdated analytical methods, and failure to integrate with the rapid development of modern testing fields (including the lack of integration with fast and accurate modern instruments), this invention provides a method for iron phase analysis in ores. This method combines magnetic separation with iron valence state discrimination. By determining the actual ratio of divalent to trivalent iron in the magnetic separation products and its deviation from the theoretical ratio of magnetite, it achieves the differentiation and quantification of three magnetic phases—magnetic iron, pseudomorphic hematite, and magnetic pig iron—in the same process. Simultaneously, for non-magnetic products, a sequential chemical extraction method based on reduction-inhibition synergy and liquid-solid phase stepwise extraction is employed to selectively dissolve and quantify iron carbonate, hematite, iron sulfide, and iron silicate sequentially. The data is validated by total iron determination.

[0031] Please refer to Figure 1 As shown, this embodiment of the invention provides a method for phase analysis of iron in ore, comprising the following steps: S1. Magnetic Separation: The ore sample is subjected to wet magnetic separation to obtain magnetic and non-magnetic products; details are as follows: Weigh 0.1000 g-0.2000 g of ore sample with a particle size less than 0.075 mm into a first 250 mL beaker. Add 10-15 mL of water and shake well until no particles adhere to the bottom of the beaker. Use a large magnet for the first magnetic separation, shaking clockwise or counterclockwise. Use a fine wash bottle to rinse the magnetic area, washing away other components into a second 250 mL beaker. Use a large magnet (approximately 10 cm in diameter) to gather the magnet in the second 250 mL beaker into one corner of the first beaker. Place a small magnet (approximately 2 cm in diameter) in a plastic tube, immerse it in the solution, and suspend it above the magnet. The magnet will automatically attract to the magnet. Rinse the magnet into the first 250 mL beaker to obtain the magnetic product. At this point, the second beaker contains the non-magnetic product.

[0032] Note 1. Do not evaporate the volume during concentration. Cover the surface with a watch glass during the concentration process.

[0033] 2. After the magnetic separation is completed, check whether there are any magnets remaining in the second 250 mL beaker.

[0034] 3. Use a fine-mesh wash bottle for rinsing, and ideally keep the rinsing volume to within 100mL.

[0035] S2. Magnetic Phase and Valence State Identification: The magnetic product is analyzed for its iron valence state. Based on the ratio of ferrous to ferric iron content and its deviation from the theoretical valence state ratio of magnetite, at least one of the following is identified and quantified: magnetic iron phase, pseudomorphic hematite phase, and / or magnetic intergrowth phase; specifically as follows: Add 1 mL of ethylene glycol and 5 mL of liquid bromine to the first beaker containing the magnetic product, shake for 10 min, and heat to concentrate until the volume is about 20 mL. Add 15 mL of hydrochloric acid, 10 mL of nitric acid, and 3 mL of perchloric acid to the beaker, and heat on a hot plate to digest. After digestion, add hydrochloric acid for leaching, controlling the acidity at 15-20%. Make up the volume of the sample according to the sample content, and determine the total amount of magnetically separated iron (ferrous and ferric iron) in the sample by ICP. Take another sample of the same mass and perform the magnetic iron determination method. Completely separate the magnetic iron, and determine the Fe content using the potassium dichromate method. 2+ The content of Fe in magnetite is calculated by subtracting the ferrous iron from the total ferric iron content. 3+ and Fe 2+ The ratio is 2:1, when Fe 3+ Use Fe when in excess 2+ ×3, when Fe 2+ Use Fe when in excess 3+ ×1.5 is used to calculate the iron content in magnetite.

[0036] Pseudo-hematite: When Fe 3+ When there is an excess, the total amount of iron separated by magnetic separation minus the content of magnetic iron is the content of pseudo-hematite.

[0037] Magnetic pig iron: When Fe 2+ When there is excess, the total amount of iron separated by magnetic separation minus the content of magnetic iron is the content of magnetic pig iron.

[0038] This step involves precise determination of Fe through chemical titration. 2+ By combining ideal proportions to deduce the true iron content of magnetite, and then using the difference in total iron from magnetic separation, the iron content of other magnetic minerals can be separated. This method utilizes the fixed cation ratio of magnetite, solving the problem of the difficulty in directly measuring the components in mixed magnetic minerals.

[0039] S3, Sequential Extraction of Non-Magnetic Phases: The non-magnetic products are sequentially subjected to stepwise chemical extraction based on a selective dissolution mechanism to obtain test solutions of ferric carbonate phase, hematite phase, ferric sulfide phase, and ferrosilicon phase, respectively; wherein, the selective dissolution of the hematite phase is carried out in a system containing a reducing agent and a co-solution inhibitor, and the extraction of the ferric sulfide phase adopts a stepwise method combining liquid-phase complexation extraction and solid-phase high-temperature digestion; the specific process is as follows: S31, Determination of ferric carbonate: Add 12.5 mL of the first extractant to the second beaker (non-magnetic product) from step S1, and dilute with water to 100 mL. If the volume of the washing solution in the beaker exceeds 100 mL, add 20 mL of the first extractant and dilute with water to 150 mL. Heat on a hot plate at 180°C for 120 minutes. Filter the solution into a 400mL beaker using double-layer quantitative filter paper. Wash the filtrate until the volume is reduced to 250-300mL. Add 1mL of sulfuric acid and heat to concentrate the filtrate to about 40mL. Remove the beaker and add 3mL of a 2:1 mixture of hydrogen peroxide and sodium hypochlorite (by volume). Place the beaker on a heating plate and continue heating for 10 minutes. Add another 2mL of the 2:1 mixture of hydrogen peroxide and sodium hypochlorite and heat until white fumes are emitted. Remove the beaker and let it cool slightly. Add 15mL of hydrochloric acid, 10mL of nitric acid, and 3mL of perchloric acid to the beaker and heat on a hot plate to digest the solution. After digestion, add hydrochloric acid to leach out the solution, maintaining the acidity at 15-20%. Adjust the volume of the sample according to its content and perform ICP analysis.

[0040] Note 1. Do not evaporate the volume during concentration. Cover the surface with a watch glass during the concentration process.

[0041] 2. Double-layer quantitative filter paper is used for filtration.

[0042] S32, Determination of hematite: Place the filter residue from step S31, along with the filter paper, into a 150mL conical flask. Add 80mL of the second extractant and 2mL of a 1:2 volume ratio mixed solution (sodium sulfite 0.5g / L: ascorbic acid 1g / L) to ensure the effective components of the second extractant. Simultaneously add 0.5mL each of the first inhibitor, KSCN (2g / L), and the second inhibitor, n-hexane. Heat on a 180℃ hot plate for 120 minutes. Filter the solution using double-layer quantitative filter paper into a 400mL beaker. Wash the filtrate until the volume is reduced to 250-300mL. Heat and concentrate the filtrate, initially at 240-260℃. Once the bubbles have stopped rising, transfer to a high-temperature furnace for further concentration until the volume is reduced to approximately 20mL. After concentration, add hydrochloric acid for leaching, controlling the acidity at 15-20%. Adjust the sample volume according to the sample content and perform ICP analysis.

[0043] Note: 1. Double-layer quantitative filter paper is used for filtration.

[0044] 2. Do not evaporate the volume during concentration; cover with a petri dish during the concentration process.

[0045] 3. Do not add triacids for digestion, as this will produce a large amount of precipitate during leaching, resulting in lower test results.

[0046] 4. After leaching, a longer cooling time is required, preferably in a fume hood.

[0047] S33, Determination of iron sulfide: Place the filter residue from step S32, along with the filter paper, into a 150mL Erlenmeyer flask, add 50mL of the third extractant, shake for 1 h, add 20mL of the fourth extractant sodium thiosulfate (2g / L), shake for 0.5 h, filter through double-layer quantitative filter paper into a 400mL beaker, wash the filtrate until the volume is 250-300mL, and heat to concentrate to about 50mL.

[0048] The filtered residue, along with the filter paper, was placed in a 100mL corundum crucible and heated to 700℃ in a fluoropolymer furnace at a low temperature. After ashing, 20mL of aqua regia was added to the crucible, and the mixture was heated on a hot plate for digestion for approximately 20 minutes (leaving about 10mL of aqua regia). The solution was then filtered through double-layered quantitative filter paper into a 400mL beaker. The filtrate was washed until the volume was reduced to 100-150mL, and then concentrated by heating until the volume was reduced to about 50mL. Combine the two concentrated solutions into a beaker, add 15 mL of hydrochloric acid, 10 mL of nitric acid, and 3 mL of perchloric acid, and heat on a hot plate for digestion. After digestion, add hydrochloric acid for leaching, controlling the acidity at 15-20%. Adjust the volume of the sample according to its content.

[0049] Note 1. Double-layer quantitative filter paper is used for filtration. 2. The volume should not be evaporated to dryness during concentration; cover the surface with a watch glass during the concentration process. S34, Determination of ferric silicate: Place the filter residue from step S33, along with the filter paper, into a 100mL corundum crucible. Place it in a fluoropolymer furnace at low temperature and heat it to 700℃. After ashing, add 0.5g sodium carbonate and 2g sodium peroxide to the hot crucible and melt it for about 20 minutes. Remove the crucible, cool it, place it in a beaker, add water, and place it on a hot plate for leaching. After leaching, add hydrochloric acid for further leaching, controlling the acidity at 20%. Adjust the volume of the sample according to the sample content, and perform ICP analysis on the sample.

[0050] S4, please refer to Figures 2 to 4 As shown, the concentration of each corresponding iron phase is calculated using the following formula: ; In the formula: W(Fe) is the mass fraction of iron in each phase, %; C represents the iron concentration (ICP) obtained from the standard curve, in μg / mL; C0 is the concentration of the blank (ICP) obtained from the standard curve, in μg / mL; V is the final volume of the sample, in mL; d represents the dilution factor of the sample; m is the mass of the sample, in grams.

[0051] Determination of total iron: Weigh 0.1 g-0.5 g of ore sample into a polytetrafluoroethylene crucible, moisten with water, add 15 mL of hydrochloric acid, 10 mL of nitric acid, 5 mL of hydrofluoric acid, and 3 mL of perchloric acid to the crucible, heat on a hot plate to digest, and after digestion, add hydrochloric acid to leach, controlling the acidity at 15-20%. Make up the volume of the sample according to the sample content, and determine the iron content of the solution in the volumetric flask by ICP, which is the total amount of iron in the ore sample.

[0052] The first extractant is acetic acid.

[0053] The second extractant is prepared by dissolving 3g of stannous chloride in 33mL of hydrochloric acid and then bringing the volume up to 100mL with water.

[0054] The third extractant is saturated bromine water.

[0055] The fourth extractant is sodium thiosulfate (10 g / L).

[0056] Example 1 Embodiment 1 of the present invention provides a method for phase analysis of iron in ore, comprising the following steps: S1, Magnetic Separation: The ore sample is subjected to wet magnetic separation to obtain magnetic and non-magnetic products; details are as follows: Determination of magnetic iron: Weigh 0.1000 g of ore sample with a particle size of less than 0.075 mm into the first 250 mL beaker, add 10-15 mL of water, shake well until no particles stick to the bottom of the beaker, use a large magnet for the first magnetic separation, shake clockwise or counterclockwise, use a fine wash bottle to rinse the magnetic area, and rinse the other components into the second 250 mL beaker. Use the large magnet to gather the magnet in the second 250 mL beaker into one corner of the beaker, place a small magnet (about 2 cm in diameter) in a plastic tube and immerse it in the solution, suspend it above the magnet, the magnet will automatically be attracted to the magnet, rinse the magnet into the first 250 mL beaker.

[0057] S2, Magnetic Phase and Valence State Identification: Add 1 mL of ethylene glycol and 5 mL of liquid bromine to the first beaker containing the magnet, shake for 10 min, and heat to concentrate until the volume is approximately 20 mL. Add 15 mL of hydrochloric acid, 10 mL of nitric acid, and 3 mL of perchloric acid to the beaker, and heat on a hot plate to digest. After digestion, add hydrochloric acid for leaching, controlling the acidity at 15-20%. Dilute the sample to a 100 mL volumetric flask and perform ICP analysis. Take another sample of the same mass and perform the magnetic iron determination method. Completely separate the magnetic iron and determine the Fe content using the potassium dichromate method. 2+ The content of Fe in magnetite is calculated by subtracting the ferrous iron from the total ferric iron content. 3+ and Fe2+ The ratio is 2:1, when Fe 3+ Use Fe when in excess 2+ ×3, when Fe 2+ Use Fe when in excess 3+ ×1.5 is used to calculate the iron content in magnetite.

[0058] The measured value (total content of divalent and trivalent iron in magnetic iron) was 7.55; the blank measured value was 0.05. According to the calculation formula, the total content of divalent and trivalent iron in magnetic iron is 0.750%. The measured content of divalent iron was 0.300%, and the content of trivalent iron was 0.450%. Fe... 2+ Excess iron. Therefore, the iron content in magnetic iron is 0.680%.

[0059] This sample does not contain pseudomorphic hematite.

[0060] Magnetic pig iron: Fe 2+ When there is excess, the total amount of iron separated by magnetic separation minus the content of magnetic iron is the content of magnetic pig iron, which is 0.07%.

[0061] S3, Sequential extraction of nonmagnetic phases: S31, Determination of ferric carbonate: Add 12.5 mL of the first extractant to the second beaker from step S1, and dilute with water to 100 mL. If the volume of the washing solution in the beaker exceeds 100 mL, add 20 mL of the first extractant and dilute with water to 150 mL. Heat on a hot plate at 180°C for 120 minutes. Filter the sample into a 400mL beaker using double-layer quantitative filter paper. Wash the filtrate until the volume is 250-300mL. Add 1mL of sulfuric acid and heat to concentrate the filtrate to about 40mL. Add 3mL of a 2:1 mixture of hydrogen peroxide and sodium hypochlorite (by volume). Place the beaker on a hot plate and continue heating for 10 minutes. Add another 2mL of the 2:1 mixture and heat until white fumes are emitted. Remove from heat and let cool slightly. Add 15mL of hydrochloric acid, 10mL of nitric acid, and 3mL of perchloric acid to the beaker and heat on a hot plate to digest the sample. After digestion, add hydrochloric acid to leach out the sample, maintaining the acidity at 15-20%. Dilute the sample to a 100mL volumetric flask and perform ICP analysis.

[0062] The measured value was 8.78; the blank measured value was 0.03; according to the calculation formula, the iron content in ferric carbonate is 0.875%.

[0063] S32, Determination of hematite: Place the filter residue from step S31, along with the filter paper, into a 150mL conical flask. Add 80mL of the second extractant and 2mL of a 1:2 volume ratio mixed solution (sodium sulfite 0.5g / L: ascorbic acid 1g / L) to ensure the effective components of the second extractant. Simultaneously add 0.5mL each of the first inhibitor, KSCN (2g / L), and the second inhibitor, n-hexane. Heat on a 180℃ hot plate for 120 minutes. Filter the solution using double-layer quantitative filter paper into a 400mL beaker. Wash the filtrate until the volume is reduced to 250-300mL. Heat and concentrate the filtrate, initially at 240-260℃. Once the bubbles have stopped rising, transfer to a high-temperature furnace for further concentration until the volume is reduced to approximately 20mL. After concentration, add hydrochloric acid for leaching, controlling the acidity at 15-20%. Volume the sample to a 100 mL volumetric flask, then take 10 mL from the flask and volume it to another 100 mL volumetric flask. Perform ICP analysis on the sample.

[0064] The measured value was 4.56; the blank measured value was 0.02; according to the calculation formula, the iron content in hematite is 4.540%.

[0065] S33, Determination of iron sulfide: Place the filter residue from step S32, along with the filter paper, into a 150mL Erlenmeyer flask, add 50mL of the third extractant, shake for 1 h, add 20mL of the fourth extractant sodium thiosulfate (2g / L), shake for 0.5 h, filter through double-layer quantitative filter paper into a 400mL beaker, wash the filtrate until the volume is 250-300mL, and heat to concentrate to about 50mL.

[0066] Place the filtered residue along with the filter paper into a 100mL corundum crucible, and place it in a fluoropolymer furnace at a low temperature. Raise the temperature to 700℃. After ashing, add 20mL of aqua regia to the crucible and heat it on a hot plate for about 20 minutes (the remaining volume of aqua regia should be about 10mL). Filter the solution into a 400mL beaker using double-layer quantitative filter paper. Wash the filtrate until the volume is reduced to 100-150mL. Heat the filtrate to concentrate it until the volume is reduced to about 50mL.

[0067] Combine the two concentrated solutions into a beaker, add 15 mL hydrochloric acid, 10 mL nitric acid, and 3 mL perchloric acid, and heat on a hot plate for digestion. After digestion, add hydrochloric acid for leaching, controlling the acidity at 15-20%. Dilute the sample to a 100 mL volumetric flask, and then take 10 mL from the flask and dilute it to a 100 mL volumetric flask. Perform ICP analysis on the sample.

[0068] The measured value was 5.58; the blank measured value was 0.01; according to the calculation formula, the iron content in iron sulfide is 5.570%.

[0069] S34, Determination of ferric silicate: Place the filter residue from step S33, along with the filter paper, into a 100mL corundum crucible. Place it in a fluoropolymer furnace at low temperature and heat it to 700℃. After ashing, add 0.5g sodium carbonate and 2g sodium peroxide to the hot crucible and melt it. Melt for about 20 minutes. Remove the crucible, cool it, place it in a beaker, add water, and place it on a hot plate for leaching. After leaching, add hydrochloric acid for further leaching, controlling the acidity at 20%. Make up the volume of the sample to a 100mL volumetric flask and perform ICP analysis on the sample.

[0070] The measured value was 3.57; the blank measured value was 0.01; according to the calculation formula, the iron content in ferric silicate is 0.356%.

[0071] S4, calculate the concentration of each corresponding iron phase using the following formula: ; In the formula: W(Fe) is the mass fraction of iron in each phase, %; C represents the iron concentration (ICP) obtained from the standard curve, in μg / mL; C0 is the concentration of the blank (ICP) obtained from the standard curve, in μg / mL; V is the final volume of the sample, in mL; d represents the dilution factor of the sample; m is the mass of the sample, in grams.

[0072] Determination of total iron: Weigh 0.1 g-0.5 g of ore sample into a polytetrafluoroethylene crucible, moisten with water, add 15 mL of hydrochloric acid, 10 mL of nitric acid, 5 mL of hydrofluoric acid, and 3 mL of perchloric acid to the crucible, heat on a hot plate for digestion, add hydrochloric acid for leaching after digestion, control the acidity at 15-20%, and dilute the sample to a 100 mL volumetric flask. Take 5 mL from the flask and dilute to a 100 mL volumetric flask. Determine the iron content of the solution in the volumetric flask by ICP, which is the total iron content in the ore sample.

[0073] The measured value was 6.06; the blank measured value was 0.01; according to the calculation formula, the total iron content was 12.1%. The total content of all iron phases was 12.1%; the total amount determined was 12.1%.

[0074] Example 2 Embodiment 2 of the present invention provides a method for phase analysis of iron in ore, comprising the following steps: S1, Magnetic Separation: The ore sample is subjected to wet magnetic separation to obtain magnetic and non-magnetic products; details are as follows: Determination of magnetic iron: Weigh 0.2000 g of ore sample with a particle size of less than 0.075 mm into the first 250 mL beaker, add 10-15 mL of water, shake well until no particles stick to the bottom of the beaker, use a large magnet for the first magnetic separation, shake clockwise or counterclockwise, use a fine wash bottle to rinse the magnetic area, and rinse the other components into the second 250 mL beaker. Use the large magnet to gather the magnet in the second 250 mL beaker into one corner of the beaker, place a small magnet (about 2 cm in diameter) in a plastic tube and immerse it in the solution, suspend it above the magnet, the magnet will automatically be attracted to the magnet, rinse the magnet into the first 250 mL beaker.

[0075] S2, Magnetic Phase and Valence State Identification: Add 1 mL of ethylene glycol and 5 mL of liquid bromine to the first beaker containing the magnet, shake for 10 min, and concentrate the volume to approximately 20 mL. Add 15 mL of hydrochloric acid, 10 mL of nitric acid, and 3 mL of perchloric acid to the beaker, and heat on a hot plate for digestion. After digestion, add hydrochloric acid for leaching, controlling the acidity at 15-20%. Dilute the sample to a 100 mL volumetric flask, and then take 10 mL of this solution and dilute it to a 100 mL volumetric flask. Perform ICP analysis on the sample. Take another sample of the same mass and perform the magnetic iron determination method. Completely separate the magnetic iron and determine the Fe content using the potassium dichromate method. 2+ The content of Fe in magnetite is calculated by subtracting the ferrous iron from the total ferric iron content. 3+ and Fe 2+ The ratio is 2:1, when Fe 3+ Use Fe when in excess 2+ ×3, when Fe 2+ Use Fe when in excess 3+ ×1.5 is used to calculate the iron content in magnetite.

[0076] The measured value (total content of divalent and trivalent iron in magnetic iron) was 5.57; the blank measured value was 0.05; according to the calculation formula, the total content of divalent and trivalent iron in magnetic iron was 2.76%; the measured content of divalent iron was 0.52%, and the content of trivalent iron was 2.24%, Fe 3+ Excess iron. Therefore, the iron content in magnetic iron is 1.56%.

[0077] Pseudo-hematite: Fe 3+ When there is excess, the total amount of iron separated by magnetic separation minus the content of magnetic iron is the pseudo-hematite content, which is 1.20%.

[0078] This sample does not contain magnetic pig iron.

[0079] S3, Sequential extraction of nonmagnetic phases: S31, Determination of ferric carbonate: Add 12.5 mL of the first extractant to the second beaker from step S1, and dilute with water to 100 mL. If the volume of the washing solution in the beaker exceeds 100 mL, add 20 mL of the first extractant and dilute with water to 150 mL. Heat on a hot plate at 180°C for 120 minutes. Filter the sample into a 400mL beaker using double-layer quantitative filter paper. Wash the filtrate until the volume is 250-300mL. Add 1mL of sulfuric acid and heat to concentrate the filtrate to about 40mL. Add 3mL of a 2:1 mixture of hydrogen peroxide and sodium hypochlorite (by volume). Place the beaker on a hot plate and continue heating for 10 minutes. Add another 2mL of the 2:1 mixture and heat until white fumes are emitted. Remove from heat and let cool slightly. Add 15mL of hydrochloric acid, 10mL of nitric acid, and 3mL of perchloric acid to the beaker and heat on a hot plate to digest the sample. After digestion, add hydrochloric acid to leach out the sample, maintaining the acidity at 15-20%. Dilute the sample to a 100mL volumetric flask and perform ICP analysis.

[0080] The measured value was 5.72; the blank measured value was 0.03; according to the calculation formula, the iron content in ferric carbonate is 0.28%.

[0081] S32, Determination of hematite: Place the filter residue from step S31, along with the filter paper, into a 150mL Erlenmeyer flask. Add 80mL of the second extractant and 2mL of a 1:2 volume ratio mixed solution (sodium sulfite 0.5g / L: ascorbic acid 1g / L) to ensure the effective components of the second extractant. Simultaneously add 0.5mL each of the first inhibitor, KSCN (2g / L), and the second inhibitor, n-hexane. Heat on a 180℃ hot plate for 120 minutes. Filter the solution using double-layer quantitative filter paper into a 400mL beaker. Wash the filtrate until the volume is reduced to 250-300mL. Heat and concentrate the filtrate, initially at 240-260℃ until all bubbles appear. Transfer to a high-temperature furnace for further concentration until the volume is reduced to approximately 20mL. After concentration, add hydrochloric acid for leaching, controlling the acidity at 15-20%. Dilute the sample to a 100mL volumetric flask and perform ICP analysis.

[0082] The measured value was 15.58; the blank measured value was 0.02; according to the calculation formula, the iron content in hematite is 0.78%.

[0083] S33, Determination of iron sulfide: Place the filter residue from step S32, along with the filter paper, into a 150mL Erlenmeyer flask, add 50mL of the third extractant, shake for 1 h, add 20mL of the fourth extractant sodium thiosulfate (2g / L), shake for 0.5 h, filter through double-layer quantitative filter paper into a 400mL beaker, wash the filtrate until the volume is 250-300mL, and heat to concentrate to about 50mL.

[0084] Place the filtered residue along with the filter paper into a 100mL corundum crucible, and place it in a fluoropolymer furnace at a low temperature. Raise the temperature to 700℃. After ashing, add 20mL of aqua regia to the crucible and heat it on a hot plate for about 20 minutes (the remaining volume of aqua regia should be about 10mL). Filter the solution into a 400mL beaker using double-layer quantitative filter paper. Wash the filtrate until the volume is reduced to 100-150mL. Heat the filtrate to concentrate it until the volume is reduced to about 50mL.

[0085] Combine the two concentrated solutions into a beaker, add 15 mL hydrochloric acid, 10 mL nitric acid, and 3 mL perchloric acid, and heat on a hot plate for digestion. After digestion, add hydrochloric acid for leaching, controlling the acidity at 15-20%. Dilute the sample to a 100 mL volumetric flask, and then take 10 mL from the flask and dilute it to a 100 mL volumetric flask. Perform ICP analysis on the sample.

[0086] The measured value was 4.51; the blank measured value was 0.01; according to the calculation formula, the iron content in iron sulfide is 2.25%.

[0087] S34, Determination of ferric silicate: Place the filter residue from step S33, along with the filter paper, into a 100mL corundum crucible. Place it in a fluoropolymer furnace at low temperature and heat it to 700℃. After ashing, add 0.5g sodium carbonate and 2g sodium peroxide to the hot crucible and melt it. Melt for about 20 minutes. Remove the crucible, cool it, place it in a beaker, add water, and place it on a hot plate for leaching. After leaching, add hydrochloric acid for further leaching, controlling the acidity at 20%. Make up the volume of the sample to a 100mL volumetric flask and perform ICP analysis on the sample.

[0088] The measured value was 10.59; the blank measured value was 0.01; according to the calculation formula, the iron content in ferric silicate is 0.53%.

[0089] S4, calculate the concentration of each corresponding iron phase using the following formula: ; In the formula: W(Fe) is the mass fraction of iron in each phase, %; C represents the iron concentration (ICP) obtained from the standard curve, in μg / mL; C0 is the concentration of the blank (ICP) obtained from the standard curve, in μg / mL; V is the final volume of the sample, in mL; d represents the dilution factor of the sample; m is the mass of the sample, in grams.

[0090] Determination of total iron: Weigh 0.2000 g of ore sample into a polytetrafluoroethylene crucible, moisten with water, add 15 mL of hydrochloric acid, 10 mL of nitric acid, 5 mL of hydrofluoric acid, and 3 mL of perchloric acid to the crucible, heat on a hot plate for digestion, add hydrochloric acid for leaching after digestion, control the acidity at 15-20%, and dilute the sample to a 100 mL volumetric flask. Take 5 mL from the flask and dilute to a 100 mL volumetric flask. Determine the iron content of the solution in the volumetric flask by ICP, which is the total iron content in the ore sample.

[0091] The measured value was 6.61; the blank measured value was 0.01; according to the calculation formula, the total iron content was 6.60%; the sum of all iron phases was 6.60%; the total measured value was 6.60%.

[0092] Example 3 Embodiment 3 of the present invention provides a method for phase analysis of iron in ore, comprising the following steps: S1, Magnetic Separation: The ore sample is subjected to wet magnetic separation to obtain magnetic and non-magnetic products; specifically as follows: Determination of magnetic iron: Weigh 0.1000 g of ore sample with a particle size of less than 0.075 mm into the first 250 mL beaker, add 10-15 mL of water, shake well until no particles stick to the bottom of the beaker, use a large magnet for the first magnetic separation, shake clockwise or counterclockwise, use a fine wash bottle to rinse the magnetic area, and rinse the other components into the second 250 mL beaker. Use the large magnet to gather the magnet in the second 250 mL beaker into one corner of the beaker, place a small magnet (about 2 cm in diameter) in a plastic tube and immerse it in the solution, suspend it above the magnet, the magnet will automatically be attracted to the magnet, rinse the magnet into the first 250 mL beaker.

[0093] S2, Magnetic Phase and Valence State Identification: Add 1 mL of ethylene glycol and 5 mL of liquid bromine to the first beaker containing the magnet, shake for 10 min, and heat to concentrate until the volume is approximately 20 mL. Add 15 mL of hydrochloric acid, 10 mL of nitric acid, and 3 mL of perchloric acid to the beaker, and heat on a hot plate to digest. After digestion, add hydrochloric acid for leaching, controlling the acidity at 15-20%. Dilute the sample to a 100 mL volumetric flask, and then take 10 mL of this solution and dilute to a 100 mL volumetric flask. Perform ICP analysis on the sample. Take another sample of the same mass and perform the magnetic iron determination method. Completely separate the magnetic iron and determine the Fe content using the potassium dichromate method. 2+ The content of Fe in magnetite is calculated by subtracting the ferrous iron from the total ferric iron content. 3+ and Fe 2+ The ratio is 2:1, when Fe 3+ Use Fe when in excess 2+ ×3, when Fe 2+ Use Fe when in excess3+ ×1.5 is used to calculate the iron content in magnetite.

[0094] The measured value (total content of divalent and trivalent iron in magnetic iron) was 8.57; the blank measured value was 0.05; according to the calculation formula, the total content of divalent and trivalent iron in magnetic iron was 8.52%. The measured content of divalent iron was 2.50%, and the content of trivalent iron was 6.02%, Fe... 3+ Excess iron. Therefore, the iron content in magnetic iron is 7.50%.

[0095] Pseudo-hematite: Fe 3+ When there is excess, the total amount of iron separated by magnetic separation minus the content of magnetic iron is the pseudo-hematite content, which is 1.20%.

[0096] This sample does not contain magnetic pig iron.

[0097] S3, Sequential extraction of nonmagnetic phases: S31, Determination of ferric carbonate: Add 12.5 mL of the first extractant to the second beaker from step S1, and dilute with water to 100 mL. If the volume of the washing solution in the beaker exceeds 100 mL, add 20 mL of the first extractant and dilute with water to 150 mL. Heat on a hot plate at 180°C for 120 minutes. Filter the sample into a 400mL beaker using double-layer quantitative filter paper. Wash the filtrate until the volume is 250-300mL. Add 1mL of sulfuric acid and heat to concentrate the filtrate to about 40mL. Add 3mL of a 2:1 mixture of hydrogen peroxide and sodium hypochlorite (by volume). Place the beaker on a hot plate and continue heating for 10 minutes. Add another 2mL of the 2:1 mixture and heat until white fumes are emitted. Remove from heat and let cool slightly. Add 15mL of hydrochloric acid, 10mL of nitric acid, and 3mL of perchloric acid to the beaker and heat on a hot plate to digest the sample. After digestion, add hydrochloric acid to leach out the sample, maintaining the acidity at 15-20%. Dilute the sample to a 100mL volumetric flask and perform ICP analysis.

[0098] The measured value was 15.83; the blank measured value was 0.03; according to the calculation formula, the iron content in ferric carbonate is 1.58%.

[0099] S32, Determination of hematite: Place the filter residue from step S31, along with the filter paper, into a 150mL conical flask. Add 80mL of the second extractant and 2mL of a 1:2 volume ratio mixed solution (sodium sulfite 0.5g / L: ascorbic acid 1g / L) to ensure the effective components of the second extractant. Simultaneously add 0.5mL each of the first inhibitor, KSCN (2g / L), and the second inhibitor, n-hexane. Heat on a 180℃ hot plate for 120 minutes. Filter the solution using double-layer quantitative filter paper into a 400mL beaker. Wash the filtrate until the volume is reduced to 250-300mL. Heat and concentrate the filtrate, initially at 240-260℃. Once the bubbles have stopped rising, transfer to a high-temperature furnace for further concentration until the volume is reduced to approximately 20mL. After concentration, add hydrochloric acid for leaching, controlling the acidity at 15-20%. Volume the sample to a 100 mL volumetric flask, then take 10 mL from the flask and volume it to another 100 mL volumetric flask. Perform ICP analysis on the sample.

[0100] The measured value was 6.56; the measured value for white iron was 0.02; according to the calculation formula, the iron content in hematite is 6.54%.

[0101] S33, Determination of iron sulfide: Place the filter residue from step S32, along with the filter paper, into a 150mL Erlenmeyer flask, add 50mL of the third extractant, shake for 1 h, add 20mL of the fourth extractant sodium thiosulfate (2g / L), shake for 0.5 h, filter through double-layer quantitative filter paper into a 400mL beaker, wash the filtrate until the volume is 250-300mL, and heat to concentrate to about 50mL.

[0102] Place the filtered residue along with the filter paper into a 100mL corundum crucible, and place it in a fluoropolymer furnace at a low temperature. Raise the temperature to 700℃. After ashing, add 20mL of aqua regia to the crucible and heat it on a hot plate for about 20 minutes (the remaining volume of aqua regia should be about 10mL). Filter the solution into a 400mL beaker using double-layer quantitative filter paper. Wash the filtrate until the volume is reduced to 100-150mL. Heat the filtrate to concentrate it until the volume is reduced to about 50mL.

[0103] Combine the two concentrated solutions into a beaker, add 15 mL hydrochloric acid, 10 mL nitric acid, and 3 mL perchloric acid, and heat on a hot plate for digestion. After digestion, add hydrochloric acid for leaching, controlling the acidity at 15-20%. Dilute the sample to a 100 mL volumetric flask, and then take 10 mL from the flask and dilute it to a 100 mL volumetric flask. Perform ICP analysis on the sample.

[0104] The measured value was 8.51; the blank measured value was 0.01; according to the calculation formula, the iron content in iron sulfide is 8.50%.

[0105] S34, Determination of ferric silicate: Place the filter residue from step S33, along with the filter paper, into a 100mL corundum crucible. Place it in a fluoropolymer furnace at low temperature and heat it to 700℃. After ashing, while the crucible is still hot, add 0.5g sodium carbonate and 2g sodium peroxide to melt it. Melt for about 20 minutes, remove the crucible, cool it, place it in a beaker, add water, and place it on a hot plate for leaching. After leaching, add hydrochloric acid for further leaching, controlling the acidity at 20%. Dilute the sample to a 100mL volumetric flask, and then take 10mL of the diluted sample and dilute it to a 100mL volumetric flask. Perform ICP analysis on the sample.

[0106] The measured value was 6.59; the blank measured value was 0.01; according to the calculation formula, the manganese content in the silicate was 6.58%.

[0107] S4, calculate the concentration of each corresponding iron phase using the following formula: ; In the formula: W(Fe) is the mass fraction of iron in each phase, %; C represents the iron concentration (ICP) obtained from the standard curve, in μg / mL; C0 is the concentration of the blank (ICP) obtained from the standard curve, in μg / mL; V is the final volume of the sample, in mL; d represents the dilution factor of the sample; m is the mass of the sample, in grams.

[0108] Determination of total iron: Weigh 0.1000 g of ore sample into a polytetrafluoroethylene crucible, moisten with water, add 15 mL of hydrochloric acid, 10 mL of nitric acid, 5 mL of hydrofluoric acid, and 3 mL of perchloric acid to the crucible, heat on a hot plate to digest, and after digestion, add hydrochloric acid to leach, controlling the acidity at 15-20%, and dilute the sample to a 100 mL volumetric flask. Take 5 mL from the flask and dilute to a 100 mL volumetric flask. Determine the iron content of the solution in the volumetric flask by ICP, which is the total iron content in the ore sample.

[0109] The measured value was 15.87; the blank measured value was 0.01; according to the calculation formula, the total iron content was 31.72%; the sum of all iron phases was 31.72%; the total measured value was 31.72%.

[0110] Comparative experiment: In step S31, without adding the mixed solution of hydrogen peroxide and sodium hypochlorite (2:1), the measured value was 8.83; the blank measured value was 0.03; according to the calculation formula, the iron content in ferric carbonate was 0.88%. This is a significant decrease compared to the actual value of 1.58%.

[0111] Example 4 Embodiment 4 of the present invention provides a method for phase analysis of iron in ore, comprising the following steps: S1, Magnetic Separation: Weigh 0.2000 g of ore sample with a particle size less than 0.075 mm into the first 250 mL beaker, add 10-15 mL of water, shake well until no particles stick to the bottom of the beaker, use a large magnet for the first magnetic separation, shake clockwise or counterclockwise, use a fine wash bottle to rinse the magnetic area, and rinse the other components into the second 250 mL beaker. Use the large magnet to gather the magnets in the second 250 mL beaker into one corner of the beaker, place a small magnet (about 2 cm in diameter) in a plastic tube and immerse it in the solution. The magnets will automatically be attracted to the magnet, and the magnets will be rinsed into the first 250 mL beaker.

[0112] S2, Magnetic Phase and Valence State Identification: Add 1 mL of ethylene glycol and 5 mL of liquid bromine to the first beaker containing the magnet, shake for 10 min, and heat to concentrate until the volume is approximately 20 mL. Add 15 mL of hydrochloric acid, 10 mL of nitric acid, and 3 mL of perchloric acid to the beaker, and heat on a hot plate to digest. After digestion, add hydrochloric acid for leaching, controlling the acidity at 15-20%. Dilute the sample to a 100 mL volumetric flask, and then take 10 mL of this solution and dilute to a 100 mL volumetric flask. Perform ICP analysis on the sample. Take another sample of the same mass and perform the magnetic iron determination method. Completely separate the magnetic iron and determine the Fe content using the potassium dichromate method. 2+ The content of Fe in magnetite is calculated by subtracting the ferrous iron from the total ferric iron content. 3+ and Fe 2+ The ratio is 2:1, when Fe 3+ Use Fe when in excess 2+ ×3, when Fe 2+ Use Fe when in excess 3+ ×1.5 is used to calculate the iron content in magnetite.

[0113] The measured value (total content of divalent and trivalent iron in magnetic iron) was 3.88; the blank measured value was 0.05; according to the calculation formula, the total content of divalent and trivalent iron in magnetic iron was 1.92%. The measured content of divalent iron was 1.02%, and the content of trivalent iron was 0.90%. Fe... 2+ Excess iron. Therefore, the iron content in magnetic iron is 1.35%.

[0114] This sample does not contain pseudomorphic hematite.

[0115] Magnetic pig iron: Fe 2+ When there is excess, the total amount of iron separated by magnetic separation minus the content of magnetic iron is the content of magnetic pig iron, which is 0.57%.

[0116] S3, Sequential extraction of nonmagnetic phases: S31, Determination of ferric carbonate: Add 12.5 mL of the first extractant to the second beaker from step S1, and dilute with water to 100 mL. If the volume of the washing solution in the beaker exceeds 100 mL, add 20 mL of the first extractant and dilute with water to 150 mL. Heat on a hot plate at 180°C for 120 minutes. Filter the sample into a 400mL beaker using double-layer quantitative filter paper. Wash the filtrate until the volume is 250-300mL. Add 1mL of sulfuric acid and heat to concentrate the filtrate to about 40mL. Add 3mL of a 2:1 mixture of hydrogen peroxide and sodium hypochlorite (by volume). Place the beaker on a hot plate and continue heating for 10 minutes. Add another 2mL of the 2:1 mixture and heat until white fumes are emitted. Remove from heat and let cool slightly. Add 15mL of hydrochloric acid, 10mL of nitric acid, and 3mL of perchloric acid to the beaker and heat on a hot plate to digest the sample. After digestion, add hydrochloric acid to leach out the sample, maintaining the acidity at 15-20%. Dilute the sample to a 100mL volumetric flask and perform ICP analysis.

[0117] The measured value was 5.87; the blank measured value was 0.03; according to the calculation formula, the iron content in ferric carbonate is 0.29%.

[0118] S32, Determination of hematite: Place the filter residue from step S31, along with the filter paper, into a 150mL conical flask. Add 80mL of the second extractant and 2mL of a 1:2 volume ratio mixed solution (sodium sulfite 0.5g / L: ascorbic acid 1g / L) to ensure the effective components of the second extractant. Simultaneously add 0.5mL each of the first inhibitor, KSCN (2g / L), and the second inhibitor, n-hexane. Heat on a 180℃ hot plate for 120 minutes. Filter the solution using double-layer quantitative filter paper into a 400mL beaker. Wash the filtrate until the volume is reduced to 250-300mL. Heat and concentrate the filtrate, initially at 240-260℃. Once the bubbles have stopped rising, transfer to a high-temperature furnace for further concentration until the volume is reduced to approximately 20mL. After concentration, add hydrochloric acid for leaching, controlling the acidity at 15-20%. Volume the sample to a 100 mL volumetric flask, then take 5 mL of the sample and volumetrically add it to the 100 mL volumetric flask. Perform ICP analysis on the sample.

[0119] The measured value was 11.42; the blank measured value was 0.02; according to the calculation formula, the iron content in hematite is 11.40%.

[0120] S33, Determination of iron sulfide: Place the filter residue from step S32, along with the filter paper, into a 150mL Erlenmeyer flask, add 50mL of the third extractant, shake for 1 h, add 20mL of the fourth extractant sodium thiosulfate (2g / L), shake for 0.5 h, filter through double-layer quantitative filter paper into a 400mL beaker, wash the filtrate until the volume is 250-300mL, and heat to concentrate to about 50mL.

[0121] Place the filtered residue along with the filter paper into a 100mL corundum crucible, and place it in a fluoropolymer furnace at a low temperature. Raise the temperature to 700℃. After ashing, add 20mL of aqua regia to the crucible and heat it on a hot plate for about 20 minutes (the remaining volume of aqua regia should be about 10mL). Filter the solution into a 400mL beaker using double-layer quantitative filter paper. Wash the filtrate until the volume is reduced to 100-150mL. Heat the filtrate to concentrate it until the volume is reduced to about 50mL.

[0122] Combine the two concentrated solutions into a beaker, add 15 mL hydrochloric acid, 10 mL nitric acid, and 3 mL perchloric acid, and heat on a hot plate for digestion. After digestion, add hydrochloric acid for leaching, controlling the acidity at 15-20%. Dilute the sample to a 100 mL volumetric flask, and then take 5 mL from the flask and dilute it to a 100 mL volumetric flask. Perform ICP analysis on the sample.

[0123] The measured value was 5.81; the blank measured value was 0.01; according to the calculation formula, the iron content in iron sulfide is 5.80%.

[0124] S34, Determination of ferric silicate: Place the filter residue from step S33, along with the filter paper, into a 100mL corundum crucible. Place it in a fluoropolymer furnace at low temperature and heat it to 700℃. After ashing, add 0.5g sodium carbonate and 2g sodium peroxide to the hot crucible and melt it. Melt for about 20 minutes. Remove the crucible, cool it, place it in a beaker, add water, and place it on a hot plate for leaching. After leaching, add hydrochloric acid for further leaching, controlling the acidity at 20%. Make up the volume of the sample to a 100mL volumetric flask and perform ICP analysis on the sample.

[0125] The measured value was 9.57; the blank measured value was 0.01; according to the calculation formula, the manganese content in the silicate was 0.48%.

[0126] S4, calculate the concentration of each corresponding iron phase using the following formula: ; In the formula: W(Fe) is the mass fraction of iron in each phase, %; C represents the iron concentration (ICP) obtained from the standard curve, in μg / mL; C0 is the concentration of the blank (ICP) obtained from the standard curve, in μg / mL; V is the final volume of the sample, in mL; d represents the dilution factor of the sample; m is the mass of the sample, in grams.

[0127] Determination of total iron: Weigh 0.1000 g of ore sample into a polytetrafluoroethylene crucible, moisten with water, add 15 mL of hydrochloric acid, 10 mL of nitric acid, 5 mL of hydrofluoric acid, and 3 mL of perchloric acid to the crucible, heat on a hot plate for digestion, add hydrochloric acid for leaching after digestion, control the acidity at 15-20%, and dilute the sample to a 100 mL volumetric flask. Take 5 mL from the flask and dilute to a 100 mL volumetric flask. Determine the iron content of the solution in the volumetric flask by ICP, which is the total iron content in the ore sample.

[0128] The measured value was 19.89; the blank measured value was 0.01; according to the calculation formula, the total iron content was 19.89%; the sum of all iron phases was 19.89%; the total measured value was 19.89%.

[0129] Comparative experiment: In step S32, without adding a mixed solution with a volume ratio of 1:2 (sodium sulfite 2g / L: ascorbic acid 3g / L), the measured value was 7.56; the blank measured value was 0.02; according to the calculation formula, the iron content in hematite was 7.54%. This is a significant decrease compared to the actual value of 11.40%.

[0130] In step S32, without the addition of the first inhibitor KSCN (2 g / L) and the second inhibitor n-hexane, the measured value was 13.52; the blank measured value was 0.02; according to the calculation formula, the iron content in hematite was 13.50%. This is a significant increase compared to the actual value of 11.40%. This is mainly because some of the iron sulfide was dissolved.

[0131] Example 5 Embodiment 5 of the present invention provides a method for phase analysis of iron in ore, comprising the following steps: S1, Magnetic Separation: Weigh 0.1000 g of ore sample with a particle size less than 0.075 mm into the first 250 mL beaker, add 10-15 mL of water, shake well until no particles stick to the bottom of the beaker, use a large magnet for the first magnetic separation, shake clockwise or counterclockwise, use a fine wash bottle to rinse the magnetic area, and rinse the other components into the second 250 mL beaker. Use the large magnet to gather the magnet in the second 250 mL beaker into one corner of the beaker, place a small magnet (about 2 cm in diameter) in a plastic tube and immerse it in the solution, suspend it above the magnet, the magnet will automatically be attracted to the magnet, and rinse the magnet into the first 250 mL beaker.

[0132] S2, Magnetic Phase and Valence State Identification: Add 1 mL of ethylene glycol and 5 mL of liquid bromine to the first beaker containing the magnet, shake for 10 min, and heat to concentrate until the volume is approximately 20 mL. Add 15 mL of hydrochloric acid, 10 mL of nitric acid, and 3 mL of perchloric acid to the beaker, and heat on a hot plate to digest. After digestion, add hydrochloric acid for leaching, controlling the acidity at 15-20%. Dilute the sample to a 100 mL volumetric flask, and then take 10 mL of this solution and dilute to a 100 mL volumetric flask. Perform ICP analysis on the sample. Take another sample of the same mass and perform the magnetic iron determination method. Completely separate the magnetic iron and determine the Fe content using the potassium dichromate method. 2+ The content of Fe in magnetite is calculated by subtracting the ferrous iron from the total ferric iron content. 3+ and Fe 2+ The ratio is 2:1, when Fe 3+ Use Fe when in excess 2+ ×3, when Fe 2+ Use Fe when in excess 3+ ×1.5 is used to calculate the iron content in magnetite.

[0133] The measured value (total content of divalent and trivalent iron in magnetic iron) was 3.71; the blank measured value was 0.05. According to the calculation formula, the total content of divalent and trivalent iron in magnetic iron is 3.66%. The measured content of divalent iron was 1.22%, and the content of trivalent iron was 2.44%, all of which was magnetic iron. Therefore, the iron content in magnetic iron is 1.35%.

[0134] This sample does not contain pseudomorphic hematite.

[0135] This sample does not contain magnetic pig iron.

[0136] S3, Sequential extraction of nonmagnetic phases: S31, Determination of ferric carbonate: Add 12.5 mL of the first extractant to the second beaker from step S1, and dilute with water to 100 mL. If the volume of the washing solution in the beaker exceeds 100 mL, add 20 mL of the first extractant and dilute with water to 150 mL. Heat on a hot plate at 180°C for 120 minutes. Filter the sample into a 400mL beaker using double-layer quantitative filter paper. Wash the filtrate until the volume is 250-300mL. Add 1mL of sulfuric acid and heat to concentrate the filtrate to about 40mL. Add 3mL of a 2:1 mixture of hydrogen peroxide and sodium hypochlorite (by volume). Place the beaker on a hot plate and continue heating for 10 minutes. Add another 2mL of the 2:1 mixture and heat until white fumes are emitted. Remove from heat and let cool slightly. Add 15mL of hydrochloric acid, 10mL of nitric acid, and 3mL of perchloric acid to the beaker and heat on a hot plate to digest the sample. After digestion, add hydrochloric acid to leach out the sample, maintaining the acidity at 15-20%. Dilute the sample to a 100mL volumetric flask and perform ICP analysis.

[0137] Measured value: 8.80; Blank measured value: 0.03 According to the calculation formula, the iron content in ferric carbonate is 0.88%.

[0138] S32, Determination of hematite: Place the filter residue from step S31, along with the filter paper, into a 150mL conical flask. Add 80mL of the second extractant and 2mL of a 1:2 volume ratio mixed solution (sodium sulfite 0.5g / L: ascorbic acid 1g / L) to ensure the effective components of the second extractant. Simultaneously add 0.5mL each of the first inhibitor, KSCN (2g / L), and the second inhibitor, n-hexane. Heat on a 180℃ hot plate for 120 minutes. Filter the solution using double-layer quantitative filter paper into a 400mL beaker. Wash the filtrate until the volume is reduced to 250-300mL. Heat and concentrate the filtrate, initially at 240-260℃. Once the bubbles have stopped rising, transfer to a high-temperature furnace for further concentration until the volume is reduced to approximately 20mL. After concentration, add hydrochloric acid for leaching, controlling the acidity at 15-20%. Volume the sample to a 100 mL volumetric flask, then take 10 mL from the flask and volume it to another 100 mL volumetric flask. Perform ICP analysis on the sample.

[0139] The measured value was 14.59; the blank measured value was 0.02; according to the calculation formula, the iron content in hematite is 14.57%.

[0140] S33, Determination of iron sulfide: Place the filter residue from step S32, along with the filter paper, into a 150mL Erlenmeyer flask, add 50mL of the third extractant, shake for 1 h, add 20mL of the fourth extractant sodium thiosulfate (2g / L), shake for 0.5 h, filter through double-layer quantitative filter paper into a 400mL beaker, wash the filtrate until the volume is 250-300mL, and heat to concentrate to about 50mL.

[0141] Place the filtered residue along with the filter paper into a 100mL corundum crucible, and place it in a fluoropolymer furnace at a low temperature. Raise the temperature to 700℃. After ashing, add 20mL of aqua regia to the crucible and heat it on a hot plate for about 20 minutes (the remaining volume of aqua regia should be about 10mL). Filter the solution into a 400mL beaker using double-layer quantitative filter paper. Wash the filtrate until the volume is reduced to 100-150mL. Heat the filtrate to concentrate it until the volume is reduced to about 50mL.

[0142] Combine the two concentrated solutions into a beaker, add 15 mL hydrochloric acid, 10 mL nitric acid, and 3 mL perchloric acid, and heat on a hot plate for digestion. After digestion, add hydrochloric acid for leaching, controlling the acidity at 15-20%. Dilute the sample to a 100 mL volumetric flask, and then take 10 mL from the flask and dilute it to a 100 mL volumetric flask. Perform ICP analysis on the sample.

[0143] The measured value was 10.80; the blank measured value was 0.01; according to the calculation formula, the iron content in iron sulfide is 10.79%.

[0144] S34, Determination of ferric silicate: Place the filter residue from step S33, along with the filter paper, into a 100mL corundum crucible. Place it in a fluoropolymer furnace at low temperature and heat it to 700℃. After ashing, add 0.5g sodium carbonate and 2g sodium peroxide to the hot crucible and melt it. Melt for about 20 minutes. Remove the crucible, cool it, place it in a beaker, add water, and place it on a hot plate for leaching. After leaching, add hydrochloric acid for further leaching, controlling the acidity at 20%. Make up the volume of the sample to a 100mL volumetric flask and perform ICP analysis on the sample.

[0145] The measured value was 5.59; the blank measured value was 0.01; according to the calculation formula, the manganese content in the silicate was 0.56%.

[0146] S4, calculate the concentration of each corresponding iron phase using the following formula: ; In the formula: W(Fe) is the mass fraction of iron in each phase, %; C represents the iron concentration (ICP) obtained from the standard curve, in μg / mL; C0 is the concentration of the blank (ICP) obtained from the standard curve, in μg / mL; V is the final volume of the sample, in mL; d represents the dilution factor of the sample; m is the mass of the sample, in grams.

[0147] Determination of total iron: Weigh 0.1000 g of ore sample into a polytetrafluoroethylene crucible, moisten with water, add 15 mL of hydrochloric acid, 10 mL of nitric acid, 5 mL of hydrofluoric acid, and 3 mL of perchloric acid to the crucible, heat on a hot plate for digestion, add hydrochloric acid for leaching after digestion, control the acidity at 15-20%, and dilute the sample to a 100 mL volumetric flask. Take 5 mL from the flask and dilute to a 100 mL volumetric flask. Determine the iron content of the solution in the volumetric flask by ICP, which is the total iron content in the ore sample.

[0148] The measured value was 15.24; the blank measured value was 0.01; according to the calculation formula, the total iron content was 30.46%; the sum of all iron phases was 30.46%; the total measured value was 30.46%.

[0149] Comparative experiment: In step S33, if the fourth extractant sodium thiosulfate is not added, the measured value is: 9.66; blank measured value: 0.01. According to the calculation formula, the iron content in iron sulfide is 9.65%, which is lower than the actual measured result of 10.79%.

[0150] In summary, this invention discloses a phase analysis method for iron in ore, belonging to the field of ore analysis technology. After magnetic separation of the ore sample, the valence state of the magnetic products is analyzed. Based on the deviation of the divalent to trivalent iron ratio from the theoretical ratio of magnetite, magnetic iron phase, pseudomorphic hematite phase, and magnetic intergrowth phase are distinguished. For non-magnetic products, selective leaching-oxidation treatment of the ferric carbonate phase, reduction-inhibition synergistic selective dissolution of the hematite phase, stepwise extraction of the ferrous sulfide phase via liquid-phase complexation-solid-phase ashing, and alkaline melting digestion of the ferric silicate phase are sequentially performed. Finally, inductively coupled plasma atomic emission spectrometry (ICP-AES) is used to determine the iron content of each phase in the test solutions and the total iron digestion solution. This invention solves key problems in traditional iron phase analysis, such as incomplete classification of magnetic iron, poor selectivity of non-magnetic phases, and insufficient applicability. By distinguishing valence states, magnetic iron is subdivided into three phases, significantly improving the mineralogical analysis capability of complex ores. ICP quantitative analysis replaces the traditional titration method, simultaneously improving detection accuracy and efficiency. Total iron verification provides an accuracy criterion for the sum of the results of each phase, making the method high-resolution, high-accuracy, and high-versatility.

[0151] It should be noted that the present invention is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments that have the same structure and perform the same effects as the technical concept within the scope of the present invention are included within the scope of the present invention. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of the present invention, are also included within the scope of the present invention.

Claims

1. A method for phase analysis of iron in ore, characterized in that, Includes the following steps: S1, Magnetic separation: The ore sample is subjected to wet magnetic separation to obtain magnetic and non-magnetic products; S2, Magnetic phase and valence state identification: The magnetic product is subjected to iron valence state analysis. Based on the content ratio of divalent iron to trivalent iron and the degree of deviation from the theoretical valence state ratio of magnetite, at least one of magnetic iron phase, pseudomorphic hematite phase, and magnetic intergrowth phase is distinguished. S3, Stepwise extraction of non-magnetic phases: The non-magnetic products are sequentially subjected to stepwise chemical extraction based on a selective dissolution mechanism to obtain test solutions of ferric carbonate phase, hematite phase, ferric sulfide phase and ferrosilicon phase respectively; wherein, the selective dissolution of the hematite phase is carried out in a system containing a reducing agent and a co-solution inhibitor; S4, Spectral Measurement and Calculation: Perform plasma atomic emission spectroscopy on the test solutions of each phase obtained in steps S2 and S3, as well as the total iron digest of the ore sample, and calculate the iron content of each phase.

2. The method for phase analysis of iron in ore according to claim 1, characterized in that, In step S3, the extraction process of the ferric carbonate phase is as follows: The non-magnetic product is mixed with the first extractant and heated to selectively dissolve the ferric carbonate phase; The extract was subjected to oxidative post-treatment, followed by acid digestion to obtain the ferric carbonate phase test solution; The first extractant is an acetic acid solution; the oxidative post-treatment adopts a composite oxidation system of hydrogen peroxide and hypochlorite, with a volume ratio of (1.5-2.5):

1.

3. The method for phase analysis of iron in ore according to claim 1, characterized in that, In step S3, the extraction process of the hematite phase is as follows: The residue after ferric carbonate extraction is mixed with a composite leaching system containing a second leaching agent, a reducing agent, and a co-solution inhibitor and heated to allow the hematite phase to selectively dissolve under conditions that inhibit the dissolution of other iron phases. The reducing agent is used to reduce ferric iron to a more soluble divalent state, and the co-solution inhibitor is used to inhibit the co-solubility of ferric silicate and / or ferric sulfide. The reducing agent comprises a complex system of sulfite and ascorbic acid, with a mass concentration ratio of 1:2; the co-solution inhibitor comprises thiocyanate and / or a nonpolar organic solvent. The thiocyanate is a potassium thiocyanate solution with a concentration of 1.5-2.5 g / L; the non-polar organic solvent is n-hexane with a dosage of 0.4-0.6 mL / L. The second extractant is a mixed solution of stannous chloride and hydrochloric acid.

4. The method for phase analysis of iron in ore according to claim 1, characterized in that, In step S3, the extraction of the iron sulfide phase adopts a stepwise extraction method, including: First liquid phase extraction: The residue after the extraction of hematite is successively contacted with the third and fourth leaching agents by shaking to partially dissolve the iron sulfide phase and obtain the first extract; Second solid-phase digestion: The filter residue after the first liquid phase extraction is subjected to high-temperature ashing and then acid digestion to obtain the second digestion solution; The first extract and the second digest were combined to obtain the iron sulfide phase test solution. The third extractant is saturated bromine water; the fourth extractant is a thiosulfate solution with a concentration of 1.5-2.5 g / L; the high-temperature ashing temperature is 650-750℃; and the acid digestion uses an aqua regia system.

5. The method for phase analysis of iron in ore according to claim 1, characterized in that, In step S3, the digestion process of the iron silicate phase is as follows: The final residue after iron sulfide extraction is subjected to alkali melting treatment to completely convert the iron silicate phase into a soluble state. After acid leaching, the iron silicate phase test solution is obtained. The alkali melting process uses a mixture of carbonate and peroxide flux, with a melting temperature of 650-750℃.

6. The method for phase analysis of iron in ore according to claim 1, characterized in that, In step S2, the iron valence state analysis includes: The magnetic product is placed in a mixed medium containing polyols and halogen oxidants and subjected to oscillation treatment to selectively oxidize / reduce the surface of the magnetic minerals. After acid digestion, the total iron content and the content of ferrous iron were determined, and the content of ferric iron was obtained by subtraction. The measured ratio of ferrous iron to ferric iron was compared with the theoretical ratio of magnetite. When ferric iron was in relative excess, it was determined that a pseudo-hematite phase existed, and when ferrous iron was in relative excess, it was determined that a magnetic intergrowth phase existed.

7. The method for phase analysis of iron in ore according to claim 6, characterized in that, The comparison includes: When ferric iron is in excess, the content of magnetic iron phase is calculated by multiplying the content of ferrous iron by the theoretical stoichiometric coefficients of ferric iron and ferrous iron. The difference between the total amount of magnetically separated iron and the content of magnetic iron phase is the content of pseudo-hematite phase iron. When ferrous iron is in excess, the iron content of the magnetic iron phase is calculated by multiplying the ferric iron content by the theoretical stoichiometric coefficients of ferrous and ferric iron. The difference between the total amount of magnetically separated iron and the iron content of the magnetic iron phase is the iron content of the magnetic intergrowth phase.

8. The method for phase analysis of iron in ore according to claim 1, characterized in that, In step S1, the separation process of magnetic components in the ore sample is as follows: A single magnetic separation enrichment was performed at the bottom of a container holding a mixture of ore sample and water using a large first magnet. A second micromagnet placed inside a sealed tube is immersed in the mixed solution to perform secondary magnetic separation and enrichment of suspended or weakly magnetic particles.

9. The method for phase analysis of iron in ore according to claim 1, characterized in that, Step S4 also includes total iron verification, the process of which is as follows: the ore sample is heated and digested using a quaternary system of hydrochloric acid-nitric acid-hydrofluoric acid-perchloric acid, and the total iron content is obtained by plasma atomic emission spectrometry, which is used for normalization correction of the results of each phase.

10. A method for phase analysis of iron in ore according to any one of claims 1 to 9, characterized in that, In step S4, the iron content of each phase is calculated according to the following formula: ； In the formula: W(Fe) is the mass fraction of iron in each phase, expressed as a percentage. C represents the iron concentration obtained from the standard curve, in μg / mL; C0 is the concentration of the blank obtained from the standard curve, in μg / mL; V is the final volume of the sample, in mL; d represents the dilution factor of the sample; m represents the mass of the sample, expressed in grams.

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