A method for enriching niobium minerals from the rare earth flotation tailings of the Botou East Mine in Bayan Obo

Abstract

The invention discloses a method for enriching niobium minerals from the rare earth flotation tailings of the main east mine in Bayan Obo. The method is characterized by using flotation to remove easily floatable minerals, grinding, magnetic separation to remove iron and silicate minerals with a relatively high specific magnetization coefficient, flotation to select niobium, roasting the niobium flotation concentrate, and magnetic separation to remove iron. The magnetic separation tailings are the niobium concentrate products. Through the phase transformation of the roasted ore and the combined separation of flotation, roasting and magnetic separation, the invention effectively separates niobium minerals from iron minerals and gangue minerals, and obtains niobium concentrates with a relatively high grade.

Description

Technical Field

[0001] The present invention relates to the technical field of mining engineering, and particularly relates to a method for enriching niobium minerals from the rare earth flotation tailings of the Main East Mine in Bayan Obo. Background Art

[0002] Since the 1970s, research on niobium ore separation has been carried out on the rare earth flotation tailings of the oxidized ores in the Main and East Mines of Bayan Obo. From the physical and chemical properties of the four main niobium-containing minerals, the specific gravities of the four minerals are 5.33 g / cm for columbite -3 、4.60 g / cm for niobian rutile -3 、4.15 g / cm for pyrochlore -3 、5.15 g / cm for euxenite -3 ,and the specific gravity differences from the iron minerals, rare earth minerals, and barite minerals in the rare earth tailings are small, making it difficult to separate them by gravity separation; the specific magnetic susceptibilities of the four minerals are (35.30 - 41.10)×10-6 cm for columbite 3 ·g -1 、(33.30 - 41.79)×10-6 cm for niobian rutile 3 ·g -1 、(2.80 - 3.10)×10-6 cm for pyrochlore 3 ·g -1 、(11.70 - 17.80)×10-6 cm for euxenite 3 ·g -1 ,both columbite and niobian rutile are weakly magnetic minerals, pyrochlore and euxenite are non-magnetic minerals, and their specific magnetic susceptibilities are close to those of rare earth minerals (12 - 14)×10-6 cm 3 ·g -1 ,and other weakly magnetic silicate minerals, so they cannot be effectively separated by single magnetic separation; the dielectric constants of columbite, niobian rutile and iron minerals are similar, and the dielectric constants of pyrochlore, euxenite and rare earth minerals are close, so electrostatic separation cannot effectively separate them either; the flotabilities of the four minerals of columbite, niobian rutile, pyrochlore and euxenite are medium or moderately difficult, and it is also difficult to obtain an ideal separation effect by using conventional single flotation methods.

[0003] The process properties of niobium minerals in Bayan Obo are less different, and the content of niobium minerals in the original ore is low, the particle size is fine, and the intergrowth and inclusion relationships are complex, making it difficult to effectively recover niobium minerals in Bayan Obo. The complex symbiosis of niobium minerals and iron mineral silicate minerals, and studying the effective separation of niobium minerals and iron minerals and targeted reduction of the silicate content are the keys to improving the grade of niobium concentrate.

[0004] The niobium content in the rare earth flotation tailings of the Main East Mine in Bayan Obo is low, the occurrence of niobium minerals in all ore bodies is complex, the physical and chemical properties of some associated minerals are very close, the embedded particle size is fine, and the separation difficulty is great. Summary of the Invention

[0005] The object of the present invention is to provide a method for enriching niobium minerals from the rare earth flotation tailings of the main east mine in Bayan Obo. Through the flotation method to remove easily floatable minerals from the rare earth flotation tailings - grinding - magnetic separation to remove iron and remove silicate minerals with a relatively high specific magnetization coefficient - flotation method to select niobium - roasting of niobium flotation concentrate - magnetic separation to remove iron, the magnetic separation tailings are the separation process of niobium concentrate products. Through the phase transformation of roasted ore and the combined separation of flotation - roasting - magnetic separation, the effective separation of niobium minerals, iron minerals and gangue minerals is realized, and niobium concentrate with a higher grade is obtained.

[0006] To solve the above technical problems, the present invention adopts the following technical solutions:

[0007] A method for enriching niobium minerals from the rare earth flotation tailings of the main east mine in Bayan Obo of the present invention adopts the flotation method to remove easily floatable minerals - grinding - magnetic separation to remove iron and remove silicate minerals with a relatively high specific magnetization coefficient - flotation method to select niobium - roasting of niobium flotation concentrate - magnetic separation to remove iron, and the magnetic separation tailings are niobium concentrate products.

[0008] Further, it specifically includes the following steps:

[0009] 1) Flotation method to remove easily floatable minerals: Using rare earth flotation tailings as raw materials, an oxygen - oxygen chelating type anionic collector and water glass as inhibitors, and adopting one - stage roughing and one - stage scavenging to float out easily floatable minerals. The steps are as follows:

[0010] ① Roughing: Under the conditions of collector dosage of 70 - 90 g / t of feed, inhibitor dosage of 2150 - 2250 g / t of feed, and PH = 8 - 9, the rare earth flotation tailings are subjected to roughing separation to obtain easily floatable minerals and roughing sand.

[0011] ② Grinding: The roughing sand is ground, and the grinding fineness reaches 88% - 90% of - 325 mesh.

[0012] ③ Scavenging: Under the condition of PH = 9, the ground minerals with a fineness of 88% - 90% of - 325 mesh are subjected to one - stage scavenging, and the collector dosage is 8 - 10 g / t of feed, to obtain scavenging tailings. The niobium mineral content in the scavenging tailings is 0.26%, and the niobium mineral recovery rate is 65%.

[0013] 2) Magnetic separation to remove iron and remove silicate minerals with a relatively high specific magnetization coefficient: Using the scavenging tailings as the raw materials for magnetic separation to remove iron and remove silicate minerals with a relatively high specific magnetization coefficient. The steps are as follows:

[0014] ① Magnetic separation to remove iron: Under the condition of a magnetic field intensity of 8000 oersted, one - stage magnetic separation to remove iron is carried out. The niobium mineral content in the magnetic separation tailings is 0.30%, and the niobium mineral recovery rate is 60%.

[0015] ②Removing silicate minerals with relatively high specific magnetization coefficient: Using the tailings of the first magnetic separation as raw materials, secondary magnetic separation is carried out under the condition of a magnetic field intensity of 11,000 oersted to remove silicate minerals such as mica, amphibole, and pyroxene. The niobium mineral content in the tailings is 0.33%, and the niobium mineral recovery rate is 50%;

[0016] 3) Selecting niobium by flotation method: Using the tailings of the secondary magnetic separation as raw materials, a positive flotation separation process of one roughing and two cleanings is adopted, and the steps are as follows:

[0017] ①Roughing: Using sulfuric acid as an adjusting agent, CMC as an inhibitor, lead nitrate as a niobium mineral activator, and a compound reagent of octadecylamine, hydroxamic acid with C5-9, hydroxamic acid with C7-9, and salicylhydroxamic acid as a niobium collector. The pulp temperature is 50 °C, and the pH value is 5-6; roughing is carried out to obtain niobium roughing concentrate and roughing tailings;

[0018] ②First cleaning: The first cleaning is carried out under the condition of a pH value of 5-6 to obtain niobium concentrate 1 and middling 1;

[0019] ③Second cleaning: The first cleaning is carried out under the condition of a pH value of 5-6 to obtain niobium concentrate with a Nb2O5 grade of 1.50% and a recovery rate of 40% and middling 2. The iron mineral content in the niobium concentrate is 45%;

[0020] ④Middling 2 is returned to the niobium roughing operation, and the roughing tailings and middling 1 are combined as the final tailings;

[0021] 5) Roasting of niobium flotation concentrate: Using niobium flotation concentrate as raw materials, roasting is carried out under the condition of a reduction atmosphere at a temperature of 500 °C and a CO:H2 = 1:3;

[0022] 6) Magnetic separation for iron removal: Using the roasted minerals as raw materials, one roughing magnetic separation is carried out under the condition of a magnetic field intensity of 1600-1800 oersted. The magnetic separation tailings are the niobium concentrate products with a Nb2O5 grade of more than 6% and a recovery rate of 30-40%.

[0023] Furthermore, a collector for easily floatable minerals with the general formula: R1-O-CH2-CH(OH)-CH2-CH(COOH)2, where R1 is selected from C7-C20 hydrocarbon groups is selected.

[0024] Furthermore, in the ① roughing of the step 3), the reagent dosages are: 5068 g / t of sulfuric acid for the feed ore, 1685 g / t of CMC for the feed ore, 1665 g / t of lead nitrate for the feed ore, and the roughing is carried out under the condition of 1750 g / t of collector for the feed ore.

[0025] Furthermore, in the ② first cleaning of the step 3), the first cleaning is carried out under the condition of a sulfuric acid dosage of 210 g / t for the feed ore and a niobium collector dosage of 290 g / t for the feed ore.

[0026] Further, in the ③ secondary beneficiation in step 3), the dosage of niobium collector is 200 g / t of the feed ore.

[0027] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0028] By adopting the combined process of flotation - magnetic separation - roasting, the iron minerals and silicate minerals that are complexly symbiotic with niobium minerals are removed step by step. First, most of the easily floatable minerals such as fluorite minerals, rare earth minerals, dolomite minerals, calcite minerals, and barite are floated out by using the principle of preferential separation of easily floatable minerals. Then, after fine grinding to open the mineral dissociation degree, the iron minerals are removed by magnetic separation with a magnetic field intensity of 8000 oersted, and the silicate minerals with a specific magnetization coefficient higher than that of niobite and niotantalite rutile, such as mica, amphibole, and pyroxene, are removed by magnetic separation with a magnetic field intensity of 11000 oersted. Due to the flotation and magnetic separation in the previous stages, the types and contents of minerals that affect the niobium grade in the flotation feed ore of niobium minerals are greatly reduced and simplified. Then, the niobium concentrate grade is increased to more than 1.5% by one roughing and two cleanings through flotation with a high - efficiency reagent combination. At this time, the iron minerals in the niobium concentrate continue to be enriched to a grade of about 45%, mainly including hematite, siderite, iron silicate, etc. This part of the iron minerals is magnetically transformed into magnetic iron through roasting and finally removed by weak magnetic separation, realizing the effective separation of niobium minerals, iron minerals, and gangue minerals, obtaining a niobium concentrate with a high grade, and solving the problem of recycling niobium minerals. In the process flow, the easily floatable minerals are the raw materials for fluorite separation, and the concentrates of the first magnetic separation and the weak magnetic separation are the raw materials for iron separation. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The present invention will be further described below in conjunction with the drawings.

[0030] Figure 1 It is the process flow diagram of the method for enriching niobium minerals from the rare earth flotation tailings of the main east mine in Bayan Obo of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0031] As Figure 1 shown, a method for enriching niobium minerals from the rare earth flotation tailings of the main east mine in Bayan Obo includes:

[0032] Treatment of raw materials: Take the rare earth separation tailings sample in the on - site production process, air - dry it naturally and mix it evenly;

[0033] 1. Removal of easily floatable minerals by flotation

[0034] Using the above raw materials, with sodium silicate as the depressant and an oxygen-oxygen chelating anionic collector with the general formula: R1-O-CH2-CH(OH)-CH2-CH(COOH)2, where R1 is selected from C7-C20 hydrocarbon groups as the collector, under the conditions of collector dosage of 70-90 g / t of feed ore, depressant dosage of 2150-2250 g / t of feed ore, and pH = 8-9, rough selection is carried out to obtain easily floatable minerals and rough selection tailings; the rough selection tailings are ground, and the grinding fineness reaches 88%-90% -325 mesh; under the condition of pH = 9, the ground minerals with a fineness of 88%-90% -325 mesh are subjected to one-stage scavenging, with a collector dosage of 8-10 g / t of feed ore, to obtain scavenging tailings. The niobium mineral content in the scavenging tailings is 0.26%, and the niobium mineral recovery rate is 65%;

[0035] 2. Magnetic separation for iron removal and removal of silicates with relatively high specific magnetization coefficients

[0036] Using the ground minerals with a fineness of 88%-90% -325 mesh as the raw material for magnetic separation for iron removal, under the condition of a magnetic field intensity of 8000 oersted, one-stage magnetic separation for iron removal is carried out. The niobium mineral content in the magnetic separation tailings is 0.30%, and the niobium mineral recovery rate is 60%; using the one-stage magnetic separation tailings as the raw material, under the condition of a magnetic field intensity of 11000 oersted, secondary magnetic separation is carried out to mainly remove silicate minerals with relatively high specific magnetization coefficients such as mica, amphibole, and pyroxene. The niobium mineral content in the tailings is 0.33%, and the niobium mineral recovery rate is 50%;

[0037] 3. Flotation for niobium

[0038] Using the above secondary magnetic separation tailings as the raw material, with sulfuric acid as the regulator, CMC as the depressant, lead nitrate as the niobium mineral activator, and a compound reagent of several reagents such as octadecylamine, hydroxamic acid with C5-9, hydroxamic acid with C7-9, and salicylhydroxamic acid as the niobium collector, the pulp temperature is 50°C, and pH = 5-6. Under the conditions of sulfuric acid dosage of 5068 g / t of feed ore, CMC dosage of 1685 g / t of feed ore, lead nitrate dosage of 1665 g / t of feed ore, and collector dosage of 1750 g / t of feed ore, rough selection is carried out to obtain niobium rough selection concentrate and rough selection tailings; under the conditions of pulp temperature of 50°C, pH = 5-6, sulfuric acid dosage of 210 g / t of feed ore, and niobium collector dosage of 290 g / t of feed ore, one-stage cleaning is carried out to obtain niobium concentrate 1 and middling 1; under the condition of pulp temperature of 50°C, pH = 5-6, and niobium collector addition of 200 g / t of feed ore, secondary cleaning is carried out to obtain niobium concentrate with a Nb2O5 grade of 1.50% and a recovery rate of 40% and middling 2. Middling 2 is returned to the niobium rough selection operation, and the rough selection tailings and middling 1 are combined as the final tailings; at this time, the iron mineral content in the niobium concentrate is about 45%;

[0039] 4. Roasting of niobium flotation concentrate

[0040] Using niobium flotation concentrate as raw material, roasting is carried out under the reducing atmosphere condition of a temperature of 500 °C and a CO:H2 ratio of 1:3;

[0041] 5. Magnetic separation for iron removal

[0042] Using the roasted minerals as raw materials, one-stage rough magnetic separation is carried out under the condition of a magnetic field intensity of 1600 - 1800 oersted. The final niobium concentrate product with a Nb2O5 grade of over 6% and a recovery rate of 30 - 40% can be obtained from the magnetic separation tailings.

[0043] The present invention will be further described in detail below in conjunction with embodiments. The following embodiments are explanations of the present invention and the present invention is not limited to the following embodiments.

[0044] The raw material used in the experiment is rare earth flotation tailings (raw material). The mineral composition analysis is shown in Table 1. The contents of easily floatable minerals such as fluorite, dolomite, calcite, rare earth minerals, barite, and apatite are relatively high. In order to eliminate the influence of easily floatable minerals on niobium separation, flotation is carried out according to the principle of floating easily floatable minerals first.

[0045] Table 1

[0046] Mineral composition (V / V%)

[0047]

[0048] 1. Removal of easily floatable minerals by flotation method

[0049] Example 1

[0050] The particle size of the raw material is 85% - 200 mesh. Direct flotation is carried out. The main flotation reagent used is water glass as an inhibitor and an oxygen-oxygen chelating type anionic collector with the general formula: R1-O-CH2-CH(OH)-CH2-CH(COOH)2, where R1 is selected from C7 - C20 hydrocarbon groups as the collector. Rough flotation is carried out under the conditions of a collector dosage of 85 g / t of feed ore, an inhibitor dosage of 2200 g / t of feed ore, a PH of 8 - 9, a flotation concentration of 40%, and a flotation temperature of 50 °C. The rough flotation foam is the raw material for fluorite separation and rare earth separation. The rough flotation tailings are ground to reach 89% - 325 mesh and then scavenged. The scavenging collector dosage is 8.5 g / t of feed ore, the flotation concentration is 35%, the flotation temperature is 50 °C, and PH = 8. Table 2 shows the mineral composition analysis of the scavenging tailings.

[0051] Table 2 Mineral composition (V / V%)

[0052]

[0053] 2. Magnetic separation for iron removal and removal of silicate minerals with relatively high specific magnetization

[0054] Example 2

[0055] This process separates the scavenged tailings under a magnetic field intensity of 8000 oersted to reduce the influence of iron minerals on niobium separation. The magnetic separation concentrate is used as the raw material for iron separation, and the magnetic separation tailings are further processed under a magnetic field intensity of 11000 oersted to remove mica, amphibole, and pyroxene silicate minerals. The niobium minerals are mainly concentrated in the magnetic separation tailings, and the mineral composition analysis is shown in Table 3.

[0056] Table 3 Mineral Composition (V / V%)

[0057]

[0058] 3. Niobium Separation by Flotation

[0059] Example 3

[0060] Using the above-mentioned secondary magnetic separation tailings as the raw material, rough separation is carried out under the conditions of a pulp temperature of 50°C, pH = 5.5, a sulfuric acid dosage of 5068 g / t of feed, a CMC dosage of 1685 g / t of feed, a lead nitrate dosage of 1665 g / t of feed, and a collector dosage of 1750 g / t of feed to obtain niobium rough separation concentrate and rough separation tailings; under the conditions of a pulp temperature of 50°C, pH = 5.5, a sulfuric acid dosage of 210 g / t of feed, and a niobium collector dosage of 290 g / t of feed, one-stage cleaning is carried out to obtain niobium concentrate 1 and middlings 1; under the conditions of a pulp temperature of 50°C, pH = 5.5, and a niobium collector addition of 200 g / t of feed, two-stage cleaning is carried out to obtain flotation niobium concentrate, and the mineral analysis is shown in Table 4.

[0061] Table 4

[0062]

[0063] 4. Roasting of Niobium Flotation Concentrate

[0064] Example 4

[0065] Using niobium flotation concentrate as the raw material, roasting is carried out under the reducing atmosphere conditions of a temperature of 500°C and a CO:H2 = 1:3 ratio, and the roasted mineral composition analysis is shown in Table 5.

[0066] Table 5

[0067]

[0068] 5. Magnetic Separation for Iron Removal

[0069] Example 5

[0070] Using the roasted minerals as the raw material, one-stage magnetic separation roughing is carried out under the magnetic field intensity conditions of 1600 - 1800 oersted. The magnetic separation tailings are the final niobium concentrate product, and the mineral composition analysis is shown in Table 6, and the multi-element analysis is shown in Table 7.

[0071] Table 6

[0072]

[0073] Table 7

[0074] TFe FeO <![CDATA[SiO2]]> P S F <![CDATA[K2O]]> <![CDATA[Na2O]]> CaO MgO 11.5 7.05 20.57 0.23 0.17 1.5 0.12 5.9 2.99 0.96 <![CDATA[AL2O3]]> MnO <![CDATA[TiO2]]> Zn BaO Sc2O3 ppm <![CDATA[Nb2O5]]> <![CDATA[ThO2]]> REO Ig 0.44 2.21 15.68 0.023 0.97 418.51 9.65 0.16 10.57 0.023

[0075] The embodiments described above are only descriptions of the preferred embodiments of the present invention and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention shall fall within the protection scope determined by the claims of the present invention.

Claims

1. A method for enriching niobium minerals from the rare earth flotation tailings of the Botou East Mine in Baiyun Obo, characterized in that, Adopt flotation method to remove easy-to-float minerals - grinding - magnetic separation for iron removal and removal of silicate minerals with relatively high specific magnetization coefficient - niobium flotation - roasting of niobium flotation concentrate - magnetic separation for iron removal, and the magnetic separation tailings are the niobium concentrate products; Specifically, it includes the following steps: Step 1) Remove easy-to-float minerals by flotation method: Use rare earth flotation tailings as raw materials, adopt oxygen-oxygen chelating anionic collector, and water glass as inhibitor. Adopt one roughing and one scavenging to float out the easy-to-float minerals. The steps are as follows: ① Roughing: Under the conditions of collector dosage of 70 - 90 g / t of feed, inhibitor dosage of 2150 - 2250 g / t of feed, and PH = 8 - 9, conduct roughing separation on rare earth flotation tailings to obtain easy-to-float minerals and roughing sand; ② Grinding: Grind the roughing sand, and the grinding fineness reaches 88% - 90% of -325 mesh; ③ Scavenging: Under the condition of PH = 9, conduct one scavenging on the ground minerals with a fineness of 88% - 90% of -325 mesh. The collector dosage is 8 - 10 g / t of feed to obtain scavenging tailings. The niobium mineral content in the scavenging tailings is 0.26%, and the niobium mineral recovery rate is 65%; Step 2) Magnetic separation for iron removal and removal of silicate minerals with relatively high specific magnetization coefficient: Use the scavenging tailings as raw materials for magnetic separation for iron removal and removal of silicate minerals with relatively high specific magnetization coefficient. The steps are as follows: ① Magnetic separation for iron removal: Conduct one magnetic separation for iron removal under the condition of magnetic field intensity of 8000 oersted. The niobium mineral content in the magnetic separation tailings is 0.30%, and the niobium mineral recovery rate is 60%; ② Remove silicate minerals with relatively high specific magnetization coefficient: Use the primary magnetic separation tailings as raw materials and conduct secondary magnetic separation under the condition of magnetic field intensity of 11000 oersted to remove mica, amphibole, and pyroxene silicate minerals. The niobium mineral content in the tailings is 0.33%, and the niobium mineral recovery rate is 50%; Step 3) Niobium flotation: Use the secondary magnetic separation tailings as raw materials and adopt the positive flotation separation process of one roughing and two cleanings. The steps are as follows: ① Roughing: Use sulfuric acid as regulator, CMC as inhibitor, lead nitrate as niobium mineral activator, and use a compound agent of several agents such as octadecylamine, hydroxamic acid with C5 - 9, hydroxamic acid with C7 - 9, and salicylhydroxamic acid as niobium collector. The pulp temperature is 50 °C, and the PH value is 5 - 6; conduct roughing to obtain niobium roughing concentrate and roughing tailings; ② First cleaning: Conduct one cleaning under the condition of PH value of 5 - 6 to obtain niobium concentrate 1 and middling 1; ③ Second cleaning: Conduct one cleaning under the condition of PH value of 5 - 6 to obtain niobium concentrate with Nb2O5 grade of 1.50% and recovery rate of 40% and middling 2. The iron mineral content in the niobium concentrate is 45%; ④ Middling 2 is returned to the niobium roughing operation, and the roughing tailings and middling 1 are combined as the final tailings; Step 4) Roasting of niobium flotation concentrate: Use niobium flotation concentrate as raw materials and conduct roasting under the condition of a reduction atmosphere with a temperature of 500 °C and CO:H2 = 1:3; Step 5) Magnetic separation for iron removal: Use the roasted minerals as raw materials and conduct one roughing magnetic separation under the condition of magnetic field intensity of 1600 - 1800 oersted. The magnetic separation tailings are the niobium concentrate products with Nb2O5 grade of more than 6% and recovery rate of 30% - 40%.

2. The method for enriching niobium minerals from the rare earth flotation tailings of the Botou East Mine in Bayan Obo, as claimed in claim 1, is characterized in that, Select a collector with the general formula: R1-O-CH2-CH(OH)-CH2-CH(COOH)2, where R1 is selected from C7-C20 hydrocarbon groups for floating minerals.

3. The method for enriching niobium minerals from the rare earth flotation tailings of the Botou East Mine in Bayan Obo according to claim 1, characterized in that, In the rough selection of step 3) ①, the dosage of reagents is as follows: sulfuric acid 5068 g / t of feed ore, CMC 1685 g / t of feed ore, lead nitrate 1665 g / t of feed ore, and the collector 1750 g / t of feed ore for rough selection.

4. The method for enriching niobium minerals from the rare earth flotation tailings of the Dong Mine in Bayan Obo Main East Mine according to claim 1, characterized in that, In the first cleaning of step 3) ②, the first cleaning is carried out under the conditions that the dosage of sulfuric acid is 210 g / t of feed ore and the dosage of niobium collector is 290 g / t of feed ore.

5. The method for enriching niobium minerals from the rare earth flotation tailings of the Botou East Mine in Baiyun Obo according to claim 1, characterized in that, In the second cleaning of step 3) ③, the dosage of niobium collector is 200 g / t of feed ore.

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