A method for recovering niobium from micro-fine and complexly disseminated and dilution ore in main east mine of Baiyunebo

Abstract

The application discloses a method for recovering niobium from micro-fine and complex embedded and lean ore in main east mine of Baiyunebo, and proposes a new niobium separation process which can be stably operated in industry according to the characteristics of different niobium minerals in main east mine of Baiyunebo and the phase of iron minerals in niobium concentrate, which comprises the following steps: 1, if the raw material is a magnetite ore, including a grinding operation, mixed flotation, mixed sand setting and sulfur flotation, sulfur tailings iron flotation, iron flotation tailings and foam respectively for niobium flotation and high-intensity magnetic separation operation; 2, if the raw material is an oxidized ore, including a grinding operation, mixed flotation, mixed sand setting and high-intensity magnetic separation, high-intensity magnetic tailings niobium flotation and flotation concentrate roasting and low-intensity magnetic separation operation. The application completely breaks the situation that the recovery of niobium minerals in main east mine of Baiyunebo has been kept in the laboratory. The application fills the blank of niobium resource separation in Baiyunebo, creates high-quality raw material conditions for downstream niobium concentrate purification process, and provides ideas for complex and refractory ores in the process of production line and development.

Description

Technical Field

[0001] This invention relates to the field of mineral processing engineering technology, and in particular to a method for recovering niobium from finely and complexly disseminated dilute ore in the main eastern mine of Bayan Obo. Background Technology

[0002] The Nb₂O₅ content of niobium minerals in the main eastern mine of Bayan Obo ranges from 0.068% to 0.14%. The main niobium minerals include columbite, columbite-rutile, calcite, chlorophyllite, and xenotime. Niobium is relatively dispersed, with fine grain sizes, generally 70-10 micrometers, some smaller than 3 micrometers, averaging 20 micrometers. Furthermore, the physicochemical properties of different niobium minerals are similar, which poses a significant challenge to the beneficiation of niobium minerals.

[0003] Currently, the niobium beneficiation process in the main eastern mine of Bayan Obo mainly adopts a process of rare earth flotation tailings-mixed flotation-mixed flotation sediment sulfur flotation-sulfur flotation tailings iron flotation-iron flotation tailings niobium flotation to obtain niobium concentrate. This process strictly requires the iron grade of the iron flotation tailings to be less than 12% in order to obtain high-grade niobium concentrate from niobium flotation. In practical applications, the iron flotation process is extremely difficult to stabilize due to the influence of ore slime content, temperature, and concentration, making it difficult to guarantee the niobium flotation feed rate. Therefore, the industrial production niobium flotation process cannot consistently obtain niobium concentrate with an Nb₂O₅ grade of over 4%.

[0004] CN 104096633 B discloses a method for separating easily floatable minerals from iron, niobium, and silicate minerals in rare earth flotation tailings through mixed flotation: the sediment from mixed flotation is separated from niobium using a process of sulfur and iron separation-gravity separation-secondary sulfur and iron separation to obtain niobium concentrate. This invention can obtain niobium concentrate with an Nb₂O₅ grade of over 5% in the laboratory stage. However, the process is relatively long, and industrial production uses shaking table separation for gravity separation. The feed particle size is very fine, and the specific gravity difference between fine-grained niobium, iron, and silicate minerals is extremely small, resulting in poor shaking table separation performance. Firstly, the enrichment effect of niobium concentrate is poor, and secondly, the amount of ore to be separated in subsequent beneficiations cannot be guaranteed, making industrial application impractical.

[0005] CN 103316771 B discloses a process for rare earth tailings-desulfurization-fluorite beneficiation-iron beneficiation-niobium beneficiation. The process flow indicates that iron tailings, middlings 1, and middlings 2 are mixed and used as raw materials for niobium beneficiation, obtaining a niobium concentrate with a Nb₂O₅ grade of 5.42% through a roughing and cleaning flotation process. However, the process does not specify the exact iron content in the niobium feed, nor does it clearly define how to control the iron content. Iron content has a significant impact on niobium flotation and is a key indicator. This process is currently only in the experimental stage. The niobium flotation reagents used include six substances: sulfuric acid, CMC, zinc sulfate, frother, salicylhydroxyxamic acid, and oxalic acid. While this reagent formulation is acceptable for laboratory adjustments, in industrial applications, fluctuations in the process flow, changes in ore properties, and unstable flotation phenomena make it difficult for on-site flotation workers to accurately judge and adjust the reagents to achieve the best addition effect. Therefore, industrial application is essentially not feasible. Summary of the Invention

[0006] The purpose of this invention is to provide a method for recovering niobium from finely and complexly disseminated, low-grade ore in the Bayan Obo Zhudong Mine. This invention completely breaks the previous situation where niobium mineral recovery from the Bayan Obo Zhudong Mine remained only in the laboratory. The results of this project fill the gap in niobium resource beneficiation in Bayan Obo, create high-quality raw material conditions for downstream niobium concentrate purification processes, and the process production line and its development can provide insights for complex and difficult-to-beneficiate ores. Based on the results of this project, the industrial application of niobium mineral beneficiation in the Bayan Obo Zhudong Mine can be promoted.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0008] This invention discloses a method for recovering niobium from finely and complexly disseminated dilute ore in the main eastern mine of Bayan Obo, comprising:

[0009] When the raw material is magnetic ore: Rare earth flotation tailings are finely ground to -325 mesh (80% or higher) and then mixed flotation is performed to remove easily floatable minerals such as fluorite, dolomite, calcite, rare earth minerals, barite, and apatite, resulting in mixed sediment. The mixed sediment is then subjected to sulfur flotation to reduce the impact of pyrite and sulfur on niobium beneficiation. The sulfur tailings are then subjected to iron flotation, requiring the iron content in the iron tailings to be reduced to 14%-19%. The grade of the flotation niobium concentrate is controlled to be above 1.5% to improve the stability of the niobium flotation process. The grade of the flotation niobium concentrate is further increased to above 4.0% through 0.8T strong magnetic separation. During the iron flotation process, most of the easily floatable niobium minerals enter the iron froth and are then subjected to a 0.5T strong magnetic separation-niobium flotation process to obtain flotation niobium concentrate, which is then processed together with the niobium concentrate from the iron tailings flotation process and fed into the 0.8T strong magnetic separation process.

[0010] When the raw material is oxidized ore: the iron minerals in the mixed sediment mainly exist in the form of Fe-hematite. They are directly separated by 0.8T strong magnetic separation. The strong magnetic concentrate is then subjected to iron flotation to obtain iron concentrate. The strong magnetic tailings are subjected to niobium flotation to obtain 2% flotation niobium concentrate. The Fe-hematite is converted into Fe-magnetite by a 500℃ reduction roasting process. The niobium concentrate with a grade of more than 9.0% is then separated by a 1800 Oersted field strength.

[0011] Optimal reagent combination for niobium flotation: Use sodium hexametaphosphate as a niobium depressant at a dosage of 1.1-1.3 kg / t feed, or carboxymethyl cellulose (CMC) at a dosage of 1.1-1.3 kg / t feed, and collector C. 5-9 The dosage of the reagent is 2.1-2.3 kg / t of ore, and the dosage of the modifier alum is 0.7-0.74 kg / t of ore. The No. 2 oil is added according to the foam phenomenon, and its main function is to prevent foam from merging and stabilize the foam layer.

[0012] Furthermore, the dosage of sodium hexametaphosphate is 1.2 kg / t of ore feed.

[0013] Furthermore, the dosage of carboxymethyl cellulose (CMC) is 1.2 kg / t of feed.

[0014] Furthermore, collector C 5-9 The dosage of the reagent is 2.2 kg / t of ore feed.

[0015] Furthermore, the dosage of the modifier alum is 0.72 kg / t of ore feed.

[0016] Furthermore, when the raw material is magnetic ore, the process includes a grinding operation, mixed flotation, mixed sedimentation sulfur flotation, sulfur tailings iron flotation, and niobium flotation and strong magnetic separation of iron flotation tailings and froth respectively; specifically, it includes the following steps:

[0017] 1) Grinding

[0018] First, the rare earth flotation tailings are finely ground to a niobium grade of 0.2-0.3%, so that the particle size of the rare earth tailings is controlled to be above 80% of -325 mesh.

[0019] 2) Mixed flotation

[0020] A mixed flotation primary roughing process was used to separate easily floatable and difficult-to-float minerals. The collector used was the low-temperature reagent TD-V (oxygen-oxygen chelate anionic collector, general formula: R1-O-CH2-CH(OH)-CH2-CH(COOH)2, where R1 is selected from C7-C20 hydrocarbon groups), at a dosage of 1.0 kg / t feed. The depressant used was water glass, at a dosage of 2.0 kg / t feed. The flotation concentration was 45%, the flotation temperature was 40℃, and the pH was 8-8.5. After mixed flotation, the content of easily floatable minerals in the sediment was significantly reduced, with fluorite grade reduced to below 5% and rare earth grade reduced to below 2%. The mixed flotation sediment yield was 60%, and the niobium metal recovery rate in the sediment was 65%. The niobium grade in the mixed sediment was enriched to above 0.2%, and iron minerals closely associated with niobium minerals were also enriched. The main gangue minerals were silicate minerals. In the mixed sediment, the niobium minerals are mostly between 5 and 20 micrometers in size, and most of them are single particles. Niobium minerals are intergrowth with iron minerals and amphibole, and occasionally large niobium mineral particles of nearly 50 micrometers can be seen.

[0021] 3) Sulfur flotation

[0022] Sulfur flotation was performed using mixed sediments, with a focus on reducing pyrite and sulfur content. The sulfur flotation reagents used were butyl xanthate and 2... # Oil, butyl xanthate dosage 1.4 kg / t feed, 2 # The oil consumption is 33.3 g / t of feed. Sulfur flotation can stably separate sulfur in concentrations ranging from 20% to 40%, with little impact on the indicators from concentration variations. The flotation temperature is ambient, and the flotation pH is 7.0. The easily floatable minerals in the sulfur tailings, such as fluorite, dolomite, calcite, rare earth minerals, barite, and apatite, are present in low concentrations; the main minerals are silicate minerals and iron minerals. The sulfur tailings yield is 80%, with niobium further enriched to approximately 0.3%. Some niobium minerals are lost during this process due to sulfur frothing.

[0023] 4) Iron positive flotation

[0024] Iron positive flotation is performed on sulfur flotation tailings to reduce the iron content in the tailings and further improve the washability of subsequent niobium. The iron positive flotation depressant, ammonium fluorosilicate, is added at a total dosage of 8.5 kg / t of feed. The collector SZ (sodium fatty acid salt 20%-45%; sodium rosinate salt 3%-10%; free alkali <1%; water 40%-60%; unsaponifiable matter <5%) is added at a total dosage of 0.5 kg / t of feed. The iron positive flotation operation requires strict control of the flotation concentration within 30% ± 2, as concentration fluctuations have a significant impact on iron positive flotation indicators. The flotation temperature must be strictly controlled between 45℃ and 50℃, and the pH must be strictly controlled at 5.5. The iron grade in the iron tailings is controlled at 14%-19%, with a tailings yield of 60%. Due to the fine grinding particle size, easily floatable niobium minerals from the positive flotation iron operation mainly enter the iron froth, while difficult-to-float niobium minerals and large-particle niobium minerals enter the tailings. The niobium grade in the tailings is generally around 2%. The main minerals in the iron tailings are silicate minerals, quartz, and feldspar. The main niobium minerals in the iron tailings are large-particle calcite, rutile-niobite, and a small amount of large-particle columbite. The iron grade in the iron froth is 49.2%, and the niobium grade is 0.54%.

[0025] 5) Niobium flotation of iron tailings

[0026] Niobium flotation is performed on iron ore tailings, with the main reagent being the inhibitor CMC at a dosage of 1.2 kg / t feed, and collector C... 5-9 The dosage is 2.2 kg / t of feed, with alum as the adjuster (0.72 kg / t of feed). The pulp pH is 6.0. #2 oil is added according to the foaming phenomenon, mainly to prevent foam coalescence and stabilize the foam layer. The reagent system is simple and highly operable on-site. The flotation temperature is 50℃, and the flotation concentration is 22% ± 2. The concentration for niobium flotation is strictly controlled and must not be too high. The rougher CMC dosage is 1.0 kg / t of feed, and the collector C... 5-9 The dosage of reagents is 1.5 kg / t of feed, and the dosage of alum is 0.7 kg / t of feed. Since the pH of iron flotation is 5.5, the pH of niobium flotation can be basically guaranteed to be 6.0, and no acid conditioning is required. The dosage of CMC in the primary cleaning stage is 0.2 kg / t of feed, and the collector is C. 5-9 Dosage of chemical reagent is 0.5 kg / t of ore, and dosage of alum is 0.02 kg / t of ore; secondary cleaning collector C. 5-9 The dosage of reagents is 0.2 kg / t of feed; no other reagents are added. The amount of No. 2 oil added is adjusted according to the froth layer condition throughout the flotation process. The niobium flotation concentrate grade reaches over 1.5%, the operating yield is approximately 4%, and the metal recovery rate is over 30%.

[0027] 6) Iron foam niobium flotation

[0028] The iron flotation froth undergoes 0.5T high-intensity magnetic separation. The magnetic concentrate is used as the raw material for iron ore beneficiation. The tailings from the magnetic separation undergo one rougher and one cleaner niobium flotation. The flotation temperature is 50℃, the flotation concentration is 22%±2, and the CMC dosage for roughing is 1.0kg / t of feed. Collector C 5-9 Dosage of chemical reagents: 2.0 kg / t feed; dosage of alum: 1.0 kg / t feed; dosage of oxalic acid: 5.0 kg / t feed to adjust the slurry pH to 6.0; dosage of No. 2 oil: 30 g / t feed; dosage of CMC for refining: 0.2 kg / t feed; dosage of collector C... 5-9 The dosage of reagent is 0.2 kg / t of ore, the dosage of alum is 0.2 kg / t of ore, the niobium grade reaches about 1%, the iron grade in the niobium concentrate is as high as 50% or more, the flotation yield is 9%, and the niobium metal recovery rate is over 30%.

[0029] 7) Intensive magnetic separation of flotation niobium concentrate.

[0030] Iron flotation tailings and flotation foam niobium flotation mixed niobium concentrate are separated by strong magnetic separation with a field strength of 0.8T. The grade of magnetically separated niobium concentrate is increased to more than 4%, the operating yield is 15%, and the niobium concentrate recovery rate is about 50%.

[0031] Furthermore, when the raw material is an oxide ore, the process includes a grinding operation, mixed flotation, mixed sedimentation with strong magnetic separation, strong magnetic tailings niobium flotation, and roasting and weak magnetic separation of the flotation concentrate; specifically, it includes the following steps:

[0032] 1) Grinding

[0033] First, the rare earth flotation tailings are finely ground to achieve a niobium grade of 0.3% and an iron grade of over 30%, thereby controlling the rare earth tailings particle size to over 80% of -325 mesh.

[0034] 2) Mixed flotation

[0035] A mixed flotation primary roughing process was used to separate easily floatable and difficult-to-float minerals. The collector used was the low-temperature reagent TD-V (oxygen-oxygen chelate anionic collector, general formula: R1-O-CH2-CH(OH)-CH2-CH(COOH)2, where R1 is selected from C7-C20 hydrocarbon groups), at a dosage of 1.0 kg / t of feed. The depressant used was water glass, at a dosage of 2.0 kg / t of feed. The flotation concentration was 45%, the flotation temperature was 40℃, and the pH was 8-8.5. After mixed flotation, the fluorite content in the mixed sediment was reduced to below 5%, the rare earth element content to below 2%, the sediment yield was about 60%, and the niobium grade was enriched to above 0.3%. The main gangue minerals were silicate minerals.

[0036] 3) Mixed sedimentation with strong magnetic separation

[0037] After the mixed sediment undergoes 0.5T strong magnetic separation, the niobium grade of the magnetic separation tailings is further increased to about 0.35%, and the iron grade is reduced to 14%-19%. The strong magnetic concentrate is used as the raw material for iron ore beneficiation, which will not be elaborated in this invention.

[0038] 4) Niobium flotation of strong magnetic tailings

[0039] The strongly magnetic tailings undergo a roughing and cleaning flotation process, with the main reagent being the inhibitor CMC at a dosage of 1.2 kg / t feed, and the collector C... 5-9 The feed dosage is 2.2 kg / t, with alum as a modifier (0.72 kg / t feed). The pulp pH is 6.0, and oxalic acid is added to adjust the pulp at 5.2 kg / t feed. The flotation temperature is 50℃, and the flotation concentration is 22% ± 2. The concentration for niobium flotation is strictly controlled and must not be too high. The rougher CMC dosage is 1.0 kg / t feed, and collector C... 5-9 Dosage of chemical reagents: 1.5 kg / t feed; alum dosage: 0.7 kg / t feed; sulfuric acid dosage: 5.2 kg / t feed; No. 2 oil dosage: 30 g / t feed; CMC dosage for primary cleaning: 0.2 kg / t feed; collector C... 5-9 Dosage of chemical reagent is 0.5 kg / t of ore, and dosage of alum is 0.02 kg / t of ore; secondary cleaning collector C. 5-9 The dosage of the reagent is 0.2 kg / t of ore; no other reagents are added.

[0040] The niobium flotation concentrate grade reaches over 1.5%, of which the iron grade is over 50%, the operating yield is 10%, and the niobium metal recovery rate is over 50%.

[0041] 5) Roasting of flotation niobium concentrate

[0042] Niobium concentrate with a flotation grade of 1.5% or higher and an iron grade of over 50% mainly exists in the form of Fe-hematite. Roasting at 500℃ in a reducing atmosphere converts the hematite into magnetite. Rare earth oxides have melting points above 2000℃, while niobium pentoxide has a melting point of 1485±5℃; roasting at 500℃ has virtually no effect on it. Sulfur has a melting point of 112.8℃ and is vaporized during roasting. Iron undergoes a reduction reaction during oxidation; higher iron content is more beneficial for improving the grade of the roasted niobium concentrate.

[0043] After roasting, the total iron content remained basically the same, the ferrous iron content increased, and the sulfur content decreased. The distribution rate of Fe-hematite / limonite decreased from about 80% to about 1%, while the distribution rate of Fe-magnetite increased from below 10% to above 80%. The niobium mineral content remained basically unchanged after roasting.

[0044] 6) After roasting, the product undergoes weak magnetic separation.

[0045] After roasting, the minerals were separated by an 1800 Oersted field strength to obtain 9.65% niobium concentrate, with an operating yield of 20% and an operating recovery rate of 80%.

[0046] Furthermore, the niobium flotation inhibitor replaces CMC with an equal amount of sodium hexametaphosphate, achieving a flotation effect comparable to that of CMC.

[0047] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0048] This invention fills the gap in niobium resource beneficiation in Bayan Obo, creates high-quality raw material conditions for downstream niobium concentrate purification processes, and the process production line and its development process can provide ideas for complex and difficult-to-beneficiate ores.

[0049] This invention can promote the industrialization of niobium mineral beneficiation in the main eastern mine of Bayan Obo.

[0050] This invention has developed a reasonable recovery process for niobium resources in the main eastern mine of Bayan Obo. The main niobium minerals, including calcite, chlorophyllite, rutile, columbite, yttrium niobite, and baotou ore, have all been recovered.

[0051] This invention explores a suitable reagent combination and reagent system for niobium flotation, which requires fewer reagent types, has good stability, good ore adaptability, strong on-site operability, and good stability. Attached Figure Description

[0052] The present invention will be further described below with reference to the accompanying drawings.

[0053] Figure 1 This is a process flow diagram for Example 1;

[0054] Figure 2 This is a process flow diagram for Example 2;

[0055] Figure 3 This is a sieve analysis diagram of rare earth tailings in Example 1. Detailed Implementation

[0056] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. The following embodiments are explanations of the present invention, but the present invention is not limited to the following embodiments.

[0057] Process inspection and on-site niobium pilot production line production data:

[0058] Example 1

[0059] 1. Rare earth flotation tailings particle size analysis

[0060]

[0061]

[0062] Particle size analysis revealed that the rare earth flotation tailings contained 82.91% -200 mesh and 59.86% -325 mesh, indicating relatively coarse particle size. The distribution patterns of niobium and fluorite minerals largely overlapped, suggesting that their particle size and intercalation characteristics are very similar. The distribution curves of niobium with those of iron and sulfur minerals showed consistent trends, indicating a close symbiotic relationship between niobium and these minerals. Since sulfur content is low and can be effectively removed by sulfur flotation, the main challenge in niobium extraction is the effective separation of iron and niobium minerals.

[0063] (1) Ф5.03×6.4 ball mill post-mill hydrocyclone overflow mixing flotation

[0064] The overflow particle size of the hydrocyclone is -325 mesh, 88%. The mixed flotation data are shown in the table below:

[0065]

[0066] Mixed flotation was carried out at a flotation concentration of 45%, a flotation temperature of 40℃, a pH of 8.5, a water glass inhibitor dosage of 2.0 kg / t feed, and a TD-V collector dosage of 1.0 kg / t feed. The resulting mixed sediment had a fluorite grade of 3.357%, a rare earth element grade of 1.403%, a yield of 60.56%, an iron content of 18.49%, and an iron recovery rate of 84.84%.

[0067] Chemical composition of mixed sediment:

[0068] Chemical composition analysis results of mixed sediment

[0069]

[0070] After mixed flotation, the grade of niobium, the main recoverable mineral in the mixed sediment, increased to 0.26%, the iron content, which is closely related to niobium minerals, increased to 25.10%, the SiO2 content, the main gangue mineral, increased to 40.41%, the CaO content decreased to 2.00%, the F content decreased to 1.09%, and the REO content decreased to 1.31%.

[0071] Mineral content analysis of mixed sediment

[0072] Mineral composition analysis results of mixed sediment

[0073]

[0074] The content of niobium minerals in the mixed sediment was 0.96%, the content of iron minerals was 25.73%, the total content of easily floatable minerals such as fluorite, dolomite, calcite, rare earth minerals, barite and apatite decreased from 48.58% to 8.35%, and the total content of silicate minerals and quartz and feldspar increased from 27.39% to 69.11%.

[0075] In the mixed sediment, the niobium minerals are mostly between 5 and 20 micrometers in size, and most of them are single particles. Niobium minerals are intergrowth with iron minerals and amphibole, and occasionally large niobium mineral particles of nearly 50 micrometers can be seen.

[0076] (2) Mixed sediment sulfur flotation

[0077] Sulfur roughing was performed on mixed sediment tailings at a normal temperature of 22℃, pH 7.0, with butyl xanthate dosage of 1.4 kg / t feed. # With an oil consumption of 33.3 g / t feed, sulfur flotation tailings containing 0.18% sulfur and 19.81% iron can be obtained. The operating yield is 81.13%, and the iron recovery rate is 84.41%. The data are shown in the table below:

[0078]

[0079] Chemical analysis of sulfur tails:

[0080] Multi-element analysis of sulfur flotation tailings

[0081]

[0082] Mineral content analysis of sulfur tailings:

[0083] Analysis of mineral content in sulfur flotation tailings

[0084]

[0085] The content of easily floatable minerals such as fluorite, dolomite, calcite, rare earth minerals, barite, and apatite in sulfur tailings is relatively low, and the main minerals are silicate minerals and iron minerals.

[0086] (3) Iron positive flotation of sulfur tailings

[0087] The iron flotation concentration was 30%, the flotation temperature was 50℃, the iron flotation pulp pH was 5.5, the inhibitor dosage was 8.5 kg / t feed, and the collector dosage was 0.5 kg / t feed. The iron tailings yield was 60.6%, the niobium metal recovery rate in the tailings was 37.86%, and the niobium metal recovery rate in the concentrate was 62.14%. The data are shown in the table below:

[0088]

[0089] Multi-element analysis of iron foam

[0090]

[0091] The iron foam contains 35.20% iron, 2.75% ferrous iron, 0.72% REO, 2.32% CaO and 1.74% MgO, 1.81% fluorine, 0.15% phosphorus, 0.26% sulfur, and 0.22% potassium, all of which are low. It also contains 5.2% sodium, 0.30% Al2O3, and 0.38% niobium minerals.

[0092] Iron foam mineral content analysis

[0093]

[0094] The main minerals in iron foam are iron minerals and silicate minerals, followed by quartz and feldspar. Other minerals such as fluorite, rare earth elements, barite, and apatite are present in very small amounts. It should be noted that the content of niobium minerals is 1.0%.

[0095] Multi-element analysis of iron tailings

[0096]

[0097] The iron tailings contain 14.35% iron, 1.10% ferrous iron, 0.28% REO, 1.39% CaO and 3.11% MgO, 1.14% fluorine, 0.053% phosphorus, 0.042% sulfur, and 0.62% potassium, all of which are low. The sodium content is 7.63%, the Al2O3 content is 1.21%, and the niobium mineral content is 0.15%, which is relatively low in the tailings.

[0098] Analysis of mineral content in iron tailings

[0099]

[0100] The main minerals in iron tailings are silicate minerals, quartz, and feldspar, with an iron mineral content of 15.55% and a niobium mineral content of 0.55%, which is relatively low compared to the 1.0% niobium mineral content in iron froth. Therefore, niobium flotation mainly aims to suppress silicate minerals and achieve the separation of niobium minerals from iron minerals.

[0101] (4) Niobium beneficiation from iron tailings

[0102] Niobium flotation concentration 22%, flotation temperature 50℃, pH 6.0, rougher CMC dosage 1.0 kg / t feed, collector C 5-9 The dosage of chemical reagent is 1.5 kg / t of feed, and the dosage of alum is 0.7 kg / t of feed; the dosage of CMC in the primary cleaning process is 0.2 kg / t of feed, and the dosage of collector C is... 5-9 Dosage of chemical reagent is 0.5 kg / t of ore, and dosage of alum is 0.02 kg / t of ore; secondary cleaning collector C. 5-9 The dosage of the reagent is 0.2 kg / t of ore feed; no other reagents are added. The data is as follows:

[0103] Tailings 78.1 0.051 20.32 Zhongkuang 1 14.34 0.1 7.31 Zhongkuang 2 3.74 0.37 7.06 Concentrate 3.84 3.53 65.31 ∑ 100 0.20 100

[0104] For niobium beneficiation from iron tailings, under otherwise unchanged conditions, the data after replacing CMC with an equal amount of sodium hexametaphosphate as the inhibitor is shown in the table below:

[0105] Niobium index after sodium hexametaphosphate replaces CMC in equal amounts

[0106] Tailings 75.13 0.062 12.87 Zhongkuang 1 16.62 0.11 7.46 Zhongkuang 2 3.98 0.39 6.33 Concentrate 3.21 4.21 73.34 ∑ 100 0.2 100

[0107] Replacing the CMC inhibitor with sodium hexametaphosphate can yield better niobium selection indicators.

[0108] Multi-element analysis of niobium concentrate

[0109]

[0110] Analysis of niobium concentrate mineral content

[0111]

[0112]

[0113] The main minerals in niobium concentrate are iron minerals and silicate minerals, followed by quartz and feldspar. The content of easily floatable minerals barite and apatite is 2.75%, while the content of other minerals such as fluorite, rare earth elements, dolomite, and calcite is very low.

[0114] (5) Niobium selection for iron foam

[0115] Select field strength 0.5T, data are shown in the table below:

[0116]

[0117] The process of using strong magnetic concentrate for iron ore beneficiation and strong magnetic tailings for niobium beneficiation is shown in the table below:

[0118]

[0119] The iron flotation froth undergoes 0.5T high-intensity magnetic separation. The magnetic concentrate is used as the raw material for iron ore beneficiation. The tailings from the magnetic separation undergo one rougher and one cleaner niobium flotation. The flotation temperature is 50℃, the flotation concentration is 20%, the pH is 6.0, and the CMC dosage for roughing is 1.0 kg / t of feed. Collector C 5-9 Dosage of chemical reagents: 2.0 kg / t feed; dosage of alum: 1.0 kg / t feed; dosage of oxalic acid: 5.0 kg / t feed; dosage of No. 2 oil: 30 g / t feed; dosage of CMC concentrate: 0.2 kg / t feed; dosage of collector C... 5-9The dosage of reagent is 0.2 kg / t of feed, the dosage of alum is 0.2 kg / t of feed, the niobium grade is 1.09%, the iron grade in the niobium concentrate is 53.6%, the flotation yield is 9.87%, and the niobium metal recovery rate is 31.89%.

[0120] 6. High-intensity magnetic separation of niobium concentrate

[0121] The iron tailings niobium flotation concentrate and the iron froth niobium flotation concentrate were combined and fed into a 0.8T high-intensity magnetic separator for separation. The data are shown in the table below:

[0122] Strong magnetic concentrate 74.00 51.5 0.60 81.76 28.66 Strong magnetic tailings 26.00 32.7 4.25 18.24 71.34 ∑ 100 46.61 1.55 100 100

[0123] Example 2

[0124] 1. Rare earth flotation tailings after grinding -325 mesh 92.5%.

[0125] Chemical analysis of rare earth flotation tailings (%)

[0126]

[0127] 2. Mixed flotation of rare earth flotation tailings

[0128] Mixed flotation was carried out at a flotation concentration of 45%, a flotation temperature of 40℃, a pH of 8.5, a water glass inhibitor dosage of 2.0 kg / t feed, and a TD-V collector dosage of 1.0 kg / t feed. The resulting mixed sediment had a rare earth content of 0.89%, but the fluorite grade was too low to be detected. The yield was 57.65%, the iron content was 36.66%, and the niobium recovery rate was 69.90%. The data are shown in the table below.

[0129] Mixed flotation data

[0130]

[0131] Chemical analysis of mixed sediments (%)

[0132]

[0133] 2. Mixed sedimentation with strong magnetic separation

[0134] The mixed sediment was subjected to 0.8T strong magnetic separation, and the data are shown in the table below:

[0135]

[0136] 3. Niobium flotation of tailings using strong magnetic separation

[0137] The high-intensity magnetic separation concentrate is used as the raw material for iron ore beneficiation. The tailings from the high-intensity magnetic separation undergo a primary roughing and secondary cleaning process for niobium, with a flotation concentration of 22%, a flotation temperature of 50℃, and a pH of 6.0. The roughing reagent dosage is 1.0 kg / t feed, and the collector is C. 5-9Dosage of chemical reagents: 1.5 kg / t feed; alum dosage: 0.7 kg / t feed; oxalic acid dosage: 5.2 kg / t feed; No. 2 oil dosage: 30 g / t feed; CMC dosage for primary cleaning: 0.2 kg / t feed; collector C... 5-9 Dosage of chemical reagent is 0.5 kg / t of ore, and dosage of alum is 0.02 kg / t of ore; secondary cleaning collector C. 5-9 The dosage of reagents is 0.2 kg / t of feed; no other reagents are added. The grade of niobium concentrate from flotation is 2.23%, the yield of niobium flotation concentrate is 12.12%, and the metal recovery rate is 73.02%. The data are shown in the table below:

[0138] Tailings 65.13 0.062 10.94 Zhongkuang 1 16.73 0.21 9.51 Zhongkuang 2 6.02 0.39 6.36 Concentrate 12.12 2.23 73.19 ∑ 100 0.37 100

[0139] Niobium float chemical analysis %

[0140]

[0141] Table 3-37 Mineral Content Analysis of Niobium Concentrate

[0142]

[0143]

[0144] Table 3-38 Chemical phase analysis results of niobium concentrate

[0145]

[0146] 4. Roasting of flotation niobium concentrate

[0147] The niobium grade is 2.23%, with a mineral content of 5.13%; the iron grade is 54.35%, with a mineral content of 76.24%, primarily existing as Fe-hematite, with a distribution rate of 86.75%; the rare earth REO grade is 2.45%, with a mineral content of 1.49%; the sulfur grade is 0.124%, with low mineral content and no separate data available. The melting points of rare earth oxides are above 2000℃, with niobium pentoxide at 1485±5℃, meaning roasting at 500℃ has virtually no effect. Sulfur has a melting point of 112.8℃ and vaporizes during roasting. Iron undergoes reduction during oxidation; higher iron content is more beneficial for improving the grade of the niobium concentrate after roasting. The chemical properties of the roasted minerals are shown in the table below:

[0148] Multi-element analysis of niobium concentrate after roasting

[0149]

[0150] Analysis of niobium concentrate mineral content after roasting

[0151]

[0152] Chemical phase analysis results of calcined niobium concentrate

[0153]

[0154]

[0155] After roasting, the total iron content remained basically the same, the ferrous iron content increased from 3.75% to 24.2%, and the sulfur content decreased. The distribution rate of Fe-hematite / limonite decreased from 86.75% to 0.54%, the distribution rate of Fe-magnetite increased from 8.28% to 94.16%, and the niobium mineral content remained basically unchanged after roasting.

[0156] 5. After roasting, the minerals undergo weak magnetic separation.

[0157] After roasting, the minerals were subjected to 1800° Oersted field magnetic separation. The data of the magnetic separation tailings, i.e., niobium concentrate, are shown in the table below:

[0158]

[0159] Multi-element analysis of magnetic separation tailings

[0160]

[0161] The roasted magnetic separation tailings (niobium concentrate) contained 11.50% iron, 7.05% ferrous iron, 10.75% REO, 2.99% CaO and 0.96% MgO, 1.50% fluorine, 0.23% phosphorus, 0.170% sulfur, 0.12% potassium, 5.90% sodium, 0.44% Al2O3, and 9.65% niobium minerals.

[0162] Analysis of mineral content in magnetic separation tailings

[0163]

[0164] The main minerals in the magnetic separation tailings (niobium concentrate) are iron minerals and silicate minerals, with rare earth minerals accounting for 10.4%. Due to their low specific magnetic susceptibility, rare earth minerals are enriched in the tailings during weak magnetic separation. The easily floatable minerals barite and apatite account for 2.03%, fluorite 1.89%, and niobium minerals 17.67%.

[0165] Chemical phase analysis results of magnetic separation tailings

[0166]

[0167] The main iron mineral in the magnetic separation tailings was Fe-iron silicate, with a distribution rate of 64.0%, followed by Fe-hematite / limonite, Fe-magnetite, Fe-siderite, and Fe-pyrite. After roasting, the minerals were separated using a 1800 Oersted field strength to obtain a 9.65% grade niobium concentrate, with an operating yield of 19.08% and an operating recovery rate of 82.58%.

[0168] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for recovering niobium from finely and complexly disseminated, low-grade ore in the main eastern mine of Bayan Obo, characterized in that, include: When the raw material is magnetic ore: Rare earth flotation tailings are finely ground to -325 mesh (80% or higher) and then mixed flotation is performed to remove easily floatable minerals such as fluorite, dolomite, calcite, rare earth minerals, barite, and apatite, resulting in mixed sediment. The mixed sediment is then subjected to sulfur flotation to reduce the impact of pyrite and sulfur on niobium beneficiation. The sulfur tailings are then subjected to iron flotation, requiring the iron content in the iron tailings to be reduced to 14%-19%. The grade of the flotation niobium concentrate is controlled to be above 1.5% to improve the stability of the niobium flotation process. The grade of the flotation niobium concentrate is further increased to above 4.0% through 0.8T strong magnetic separation. During the iron flotation process, most of the easily floatable niobium minerals enter the iron froth and are then subjected to a 0.5T strong magnetic separation-niobium flotation process to obtain flotation niobium concentrate, which is then processed together with the niobium concentrate from the iron tailings flotation process and fed into the 0.8T strong magnetic separation process. When the raw material is oxidized ore: the iron minerals in the mixed sediment mainly exist in the form of Fe-hematite. They are directly separated by 0.8T strong magnetic separation. The strong magnetic concentrate is then subjected to iron flotation to obtain iron concentrate. The strong magnetic tailings are subjected to niobium flotation to obtain 2% flotation niobium concentrate. The Fe-hematite is converted into Fe-magnetite by a 500℃ reduction roasting process. The niobium concentrate with a grade of more than 9.0% is then separated by a 1800 Oersted field strength. Optimal reagent combination for niobium flotation: Select sodium hexametaphosphate as the niobium depressant at a dosage of 1.1-1.3 kg / t feed, or carboxymethyl cellulose (CMC) at a dosage of 1.1-1.3 kg / t feed, and collector C. 5-9 The dosage of the reagent is 2.1-2.3 kg / t of ore, and the dosage of the modifier alum is 0.7-0.74 kg / t of ore. The No. 2 oil is added according to the foam phenomenon, and its main function is to prevent foam from merging and stabilize the foam layer.

2. The method for recovering niobium from finely and complexly disseminated low-grade ore in the main eastern mine of Bayan Obo, as described in claim 1, is characterized in that... The dosage of sodium hexametaphosphate is 1.2 kg / t of ore feed.

3. The method for recovering niobium from finely and complexly disseminated low-grade ore in the main eastern mine of Bayan Obo, as described in claim 1, is characterized in that... The dosage of carboxymethyl cellulose (CMC) is 1.2 kg / t of feed.

4. The method for recovering niobium from finely and complexly disseminated low-grade ore in the main eastern mine of Bayan Obo, as described in claim 1, is characterized in that... Collector C 5-9 The dosage of the reagent is 2.2 kg / t of ore feed.

5. The method for recovering niobium from finely and complexly disseminated low-grade ore in the main eastern mine of Bayan Obo, as described in claim 1, is characterized in that... The dosage of alum as a modifier is 0.72 kg / t of ore feed.

6. The method for recovering niobium from finely and complexly disseminated low-grade ore in the main eastern mine of Bayan Obo, as described in claim 1, is characterized in that... When the raw material is magnetic ore, the process includes a grinding operation, mixed flotation, mixed sedimentation sulfur flotation, sulfur tailings iron flotation, and niobium flotation and high-intensity magnetic separation of iron flotation tailings and froth. Specifically, it includes the following steps: 1) Grinding First, the rare earth flotation tailings are finely ground to a niobium grade of 0.2-0.3%, so that the particle size of the rare earth tailings is controlled to be above 80% of -325 mesh. 2) Mixed flotation A mixed flotation primary roughing process was used to separate easily floatable and difficult-to-float minerals. The collector used was the low-temperature reagent TD-V, at a dosage of 1.0 kg / t of feed; the depressant used was water glass, at a dosage of 2.0 kg / t of feed; the flotation concentration was 45%, the flotation temperature was 40℃, and the pH was 8-8.

5. After mixed flotation, the content of easily floatable minerals in the sediment was significantly reduced, with fluorite grade reduced to below 5% and rare earth grade reduced to below 2%. The mixed flotation sediment yield was 60%, and the niobium metal recovery rate in the sediment was 65%. The niobium grade in the mixed sediment was enriched to above 0.2%, and iron minerals closely associated with niobium minerals were also enriched synchronously. The main gangue minerals were silicate minerals. The niobium minerals in the mixed sediment mostly had a particle size between 5-20 micrometers, and most of them were single particles. Niobium minerals were intergrowthed with iron minerals and amphibole, and occasionally large niobium mineral particles of nearly 50 micrometers were visible. 3) Sulfur flotation Sulfur flotation was performed using mixed sediment to reduce pyrite and sulfur content. The flotation reagents used were butyl xanthate and No. 2 oil. The dosage of butyl xanthate was 1.4 kg / t feed, and the dosage of No. 2 oil was 33.3 g / t feed. Sulfur flotation was stable in the concentration range of 20%-40%, and concentration changes had little impact on the indicators. The flotation temperature was room temperature, and the flotation pH was 7.

0. The easily floatable minerals in the sulfur tailings, such as fluorite, dolomite, calcite, rare earth minerals, barite, and apatite, were all in low concentrations; the main minerals were silicate minerals and iron minerals. The sulfur tailings yield was 80%, and the niobium grade was further enriched to 0.3%. Some niobium minerals were lost during the sulfur frothing process. 4) Iron positive flotation Iron positive flotation is performed on sulfur flotation tailings to reduce the iron content in the tailings and further improve the washability of subsequent niobium. The iron positive flotation depressant, ammonium fluorosilicate, is added at a total dosage of 8.5 kg / t of feed, and the collector, SZ, is added at a total dosage of 0.5 kg / t of feed. The iron positive flotation operation requires strict control of the flotation concentration within 30% ± 2%, as concentration fluctuations have a significant impact on iron positive flotation indicators. The flotation temperature must be strictly controlled between 45℃ and 50℃, and the pH must be strictly controlled at 5.

5. The iron grade in the iron tailings... The tailings yield is controlled at 14%-19%, with a tailings yield of 60%. Because the grinding particle size is relatively fine, the easily floatable niobium minerals in the positive flotation iron operation are basically put into the iron froth, while the difficult-to-float niobium minerals and large-particle niobium minerals are put into the tailings. The niobium grade in the tailings is generally 2%. The main minerals in the iron tailings are silicate minerals, quartz and feldspar. The main niobium minerals in the iron tailings are large-particle calcite, rutile niobite, and a small amount of large-particle columbite. The iron grade in the iron froth is 49.2%, and the niobium grade is 0.54%. 5) Niobium flotation of iron tailings Niobium flotation is performed on iron ore tailings, with the main reagent being the inhibitor CMC at a dosage of 1.2 kg / t feed, and collector C... 5-9 The dosage is 2.2 kg / t of ore feed. The pH of the ore slurry is adjusted to 6.0 with alum. No. 2 oil is added according to the foaming phenomenon. Its main function is to prevent foam aggregation and stabilize the foam layer. Flotation temperature 50℃, flotation concentration 22%±2%, niobium flotation concentration strictly controlled, must not be too high; rougher CMC dosage 1.0kg / t feed, collector C 5-9 The dosage of reagents is 1.5 kg / t of feed, and the dosage of alum is 0.7 kg / t of feed. Since the pH of iron flotation is 5.5, the pH of niobium flotation can be basically guaranteed to be 6.0, and no acid conditioning is required. The dosage of CMC in the primary cleaning stage is 0.2 kg / t of feed, and the collector is C. 5-9 Dosage of chemical reagent is 0.5 kg / t of ore, and dosage of alum is 0.02 kg / t of ore; secondary cleaning collector C. 5-9 The dosage of reagents is 0.2 kg / t of feed, and no other reagents are added; the addition of No. 2 oil is adjusted according to the state of the froth layer throughout the flotation process; the niobium flotation concentrate grade reaches 1.5% or more, the operating yield is 4%, and the metal recovery rate is 30% or more; 6) Iron foam niobium flotation The iron flotation froth undergoes 0.5T high-intensity magnetic separation. The magnetic concentrate is used as the raw material for iron ore beneficiation. The tailings from the magnetic separation undergo one rougher and one cleaner niobium flotation. The flotation temperature is 50℃, the flotation concentration is 22% ± 2%, and the CMC dosage for roughing is 1.0 kg / t of feed. Collector C 5-9 Dosage of chemical reagents: 2.0 kg / t feed; dosage of alum: 1.0 kg / t feed; dosage of oxalic acid: 5.0 kg / t feed to adjust the slurry pH to 6.0; dosage of No. 2 oil: 30 g / t feed; dosage of CMC for refining: 0.2 kg / t feed; dosage of collector C... 5-9 The dosage of reagent is 0.2 kg / t of ore, the dosage of alum is 0.2 kg / t of ore, the niobium grade reaches 1%, the iron grade in the niobium concentrate is as high as 50% or more, the flotation yield is 9%, and the niobium metal recovery rate is over 30%. 7) Intensive magnetic separation of flotation niobium concentrate. The flotation-mixed niobium concentrate is separated by strong magnetic separation with a field strength of 0.8T. The grade of the magnetically separated niobium concentrate is increased to more than 4%, the operating yield is 15%, and the niobium concentrate recovery rate is 50%.

7. The method for recovering niobium from finely and complexly disseminated low-grade ore in the main eastern mine of Bayan Obo, as described in claim 1, is characterized in that... When the raw material is oxidized ore, the process includes a first-stage grinding operation, mixed flotation, mixed sedimentation with strong magnetic separation, strong magnetic tailings niobium flotation, and roasting and weak magnetic separation of flotation concentrate; specifically, it includes the following steps: 1) Grinding First, the rare earth flotation tailings are finely ground to achieve a niobium grade of 0.3% and an iron grade of over 30%, thereby controlling the rare earth tailings particle size to over 80% of -325 mesh. 2) Mixed flotation A mixed flotation primary roughing process was used to separate easily floatable and difficult-to-float minerals. The collector used was the low-temperature reagent TD-V, at a dosage of 1.0 kg / t of feed; the depressant used was water glass, at a dosage of 2.0 kg / t of feed; the flotation concentration was 45%, the flotation temperature was 40℃, and the pH was 8-8.

5. After mixed flotation, the fluorite content in the mixed sediment was reduced to below 5%, the rare earth element content was reduced to below 2%, the sediment yield was 60%, and the niobium grade was enriched to above 0.3%. The main gangue minerals were silicate minerals. 3) Mixed sedimentation with strong magnetic separation After the mixed sediment undergoes 0.5T high-intensity magnetic separation, the niobium grade of the magnetic separation tailings is further increased to 0.35%, and the iron grade is reduced to 14%-19%; the high-intensity magnetic concentrate is used as raw material for iron ore beneficiation. 4) Niobium flotation of strong magnetic tailings The strongly magnetic tailings undergo a roughing and cleaning flotation process, with the main reagent being the inhibitor CMC at a dosage of 1.2 kg / t feed, and the collector C... 5-9 The dosage is 2.2 kg / t of feed, with alum as the adjuster to adjust the slurry pH to 6.0, and oxalic acid added to adjust the slurry to 5.2 kg / t of feed; the flotation temperature is 50℃, and the flotation concentration is 22% ± 2%. The concentration for niobium flotation is strictly controlled and must not be too high; the rougher CMC dosage is 1.0 kg / t of feed, and collector C... 5-9 Dosage of chemical reagents: 1.5 kg / t feed; alum dosage: 0.7 kg / t feed; sulfuric acid dosage: 5.2 kg / t feed; No. 2 oil dosage: 30 g / t feed; CMC dosage for primary cleaning: 0.2 kg / t feed; collector C... 5-9 Dosage of chemical reagent is 0.5 kg / t of ore, and dosage of alum is 0.02 kg / t of ore; secondary cleaning collector C. 5-9 The dosage of the reagent is 0.2 kg / t of ore feed; no other reagents are added. The niobium flotation concentrate grade reaches 1.5% or higher, of which the iron grade is 50% or higher, the operating yield is 10%, and the niobium metal recovery rate is 50% or higher. 5) Roasting of flotation niobium concentrate Niobium concentrate with a flotation grade of 1.5% or higher and an iron grade of over 50% mainly exists in the form of Fe-hematite. Roasting at 500℃ in a reducing atmosphere converts the hematite into magnetite. The melting points of rare earth oxides are above 2000℃, with niobium pentoxide at 1485±5℃; roasting at 500℃ has virtually no effect on it. Sulfur has a melting point of 112.8℃ and is vaporized during roasting. Iron undergoes a reduction reaction during oxidation; higher iron content is more beneficial for improving the grade of the roasted niobium concentrate. After roasting, the total iron content remained basically the same, the ferrous iron content increased, and the sulfur content decreased; the distribution rate of Fe-hematite / limonite decreased from 80% to 1%, the distribution rate of Fe-magnetite increased from below 10% to above 80%, and the niobium mineral content remained basically unchanged after roasting. 6) After roasting, the product undergoes weak magnetic separation. After roasting, the minerals were separated by an 1800 Oersted field strength to obtain 9.65% niobium concentrate, with an operating yield of 20% and an operating recovery rate of 80%.

8. The method for recovering niobium from finely and complexly disseminated low-grade ore in the main eastern mine of Bayan Obo, as described in claim 7, is characterized in that... The niobium flotation inhibitor replaces an equal amount of CMC with sodium hexametaphosphate, achieving a flotation effect comparable to that of CMC.

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