A beneficiation method for comprehensively recovering niobium, rare earth and pyrite from low-grade niobium ore

Abstract

The application discloses a beneficiation method for comprehensively recovering niobium, rare earth and pyrite from low-grade niobium ore, and comprises the following steps: (1) grinding: grinding the niobium ore after crushing to a fineness of 85% to 87% of 0.038 mm, and then adjusting the ore pulp concentration to 25% to 30%; (2) pre-concentration by strong magnetic separation; (3) re-concentration of the rough magnetic separation concentrate by gravity separation; (4) re-separation of the middling concentrate; and (5) flotation separation of the gravity separation concentrate: combining the gravity separation concentrate 1 in the step (3) and the gravity separation concentrate 2 in the step (4) to obtain a gravity separation concentrate, wherein the gravity separation concentrate is a mixed concentrate rich in niobite, rare earth and pyrite; and after the gravity separation concentrate is adjusted into an ore pulp with a concentration of 25% to 35%, the ore pulp is subjected to flotation separation. The application is aimed at the multi-metal low-grade niobium ore with niobite, rare earth and pyrite being associated, realizes efficient separation among the niobium ore, the rare earth ore, the pyrite ore and the gangue ore, and achieves the purpose of comprehensively recovering the niobite, the rare earth and the pyrite.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of mineral processing engineering, and particularly relates to a beneficiation method for comprehensively recovering niobium, rare earth and pyrite from low-grade niobium ore. BACKGROUND

[0002] Niobium is an important rare strategic metal, which has excellent properties such as corrosion resistance, high temperature resistance, wear resistance, superconductivity, and is widely used in the fields of electronics, superconductivity, aerospace, atomic energy, biomedicine and the like. According to statistics, the proven reserves of niobium resources in the world exceed 17 million tons, mainly concentrated in Brazil, Canada, China and Australia and other regions. With the continuous development of world science and technology and the continuous growth of electronic product consumption, the demand for niobium metal is increasing.

[0003] China is rich in niobium resources, but most of them are polymetallic associated deposits, which have the characteristics of low niobium grade, complex ore composition and fine dissemination size, resulting in great difficulty in utilizing niobium resources, which cannot meet the growing consumption demand. At present, the beneficiation methods of niobium ore mainly include gravity separation, magnetic separation, flotation and electric separation, etc. These processes are mainly used for recovering single component and easy-to-select niobium ore. For complex and refractory niobium ore, how to effectively recover useful minerals is a problem faced by beneficiation workers. The present application develops a beneficiation method for comprehensively recovering niobium, rare earth and pyrite for the polymetallic low-grade niobium ore associated with niobite, rare earth and pyrite, which has important significance for promoting the comprehensive utilization of niobium resources in China. SUMMARY

[0004] The purpose of the present application is to provide a beneficiation method for comprehensively recovering niobium, rare earth and pyrite from low-grade niobium ore, which can realize efficient separation between niobium minerals, rare earth minerals, pyrite minerals and gangue minerals, and achieve the purpose of comprehensively recovering niobium, rare earth and pyrite.

[0005] To solve the above technical problems, the present application adopts the following technical scheme:

[0006] The present application provides a beneficiation method for comprehensively recovering niobium, rare earth and pyrite from low-grade niobium ore, which comprises the following steps:

[0007] (1) Grinding:

[0008] Grinding the niobium ore after crushing to a fineness of 85% to 87% of -0.038mm, and then adjusting the pulp concentration to 25% to 30%;

[0009] (2) Pre-enrichment by strong magnetic separation:

[0010] The ore slurry in step (1) is subjected to one rough magnetic separation and two scavenging magnetic separations by a vertical ring and high gradient magnetic separator to pre-enrich the valuable components in the niobium ore; the rough magnetic separation produces a rough magnetic separation concentrate, the concentrates of the first scavenging magnetic separation and the second scavenging magnetic separation are combined to form middlings 1, and the underflow of the second scavenging magnetic separation is tailings 1;

[0011] (3) Re-enrichment of the rough magnetic separation concentrate by gravity separation:

[0012] The rough magnetic separation concentrate in step (2) is subjected to two cleaning separations by a gravity separation device, i.e., a suspension cone separator, to further enrich the rough magnetic separation concentrate; the middlings and tailings of the first cleaning separation are combined to form middlings 2, the concentrate and middlings of the second cleaning separation are combined to form gravity separation concentrate 1, and the tailings of the second cleaning separation are middlings 3;

[0013] (4) Concentration of the middlings for re-separation:

[0014] The middlings 1 in step (2) and the middlings 2 and 3 in step (3) are combined, and after being conditioned, the mixture is ground to a fineness of 90% to 95% passing 0.038 mm; the ground mixture is conditioned and subjected to rough magnetic separation and two cleaning separations by a suspension cone separator; the underflow of the rough magnetic separation is tailings 2, the concentrate of the second cleaning separation is gravity separation concentrate 2, the middlings and tailings of the first cleaning separation are combined to form tailings 3, the middlings and tailings of the second cleaning separation are combined to form tailings 4, and the tailings 1 to 4 are combined to form total tailings;

[0015] (5) Flotation separation of the gravity separation concentrate:

[0016] The gravity separation concentrate 1 in step (3) and the gravity separation concentrate 2 in step (4) are combined to form a gravity separation concentrate which is a mixed concentrate rich in niobite, rare earth and pyrite; the gravity separation concentrate is conditioned to a pulp having a concentration of 25% to 35% and subjected to flotation separation;

[0017] First, the pyrite is floated off: butyl xanthate is used as a collector, No. 2 oil is used as a frother, and the flotation process is one rough separation and one scavenging separation; the froth of the rough separation and the scavenging separation is combined to form a pyrite concentrate; second, the rare earth is floated: water glass and sodium fluosilicate are used as depressants, salicylhydroxamic acid is used as a collector, and No. 2 oil is used as a frother; the flotation process is one rough separation and three scavenging separations; the froth of the rough separation and the scavenging separations is combined to form a rare earth concentrate; finally, the underflow in the tank is a niobium concentrate.

[0018] Further, in step (1), the grade of niobium (NbOs) in the raw ore is 0.08% to 0.12%, and the main niobium mineral is niobite, which is finely disseminated and associated with rare earth, pyrite, a small amount of ilmenite and gangue minerals; the main gangue is at least mica, dolomite, feldspar and calcite.

[0019] Further, the process parameters in the step (2) are: the magnetic field strength of the strong magnetic roughing is 1.4T, the magnetic field strength of the strong magnetic scavenging I and II is 1.4-1.6T; the flushing water amount of the strong magnetic roughing and scavenging is 10-12L / min, and the pulsation frequency is 240-260 times / min (preferably 250 times / min).

[0020] Further, the process parameters of the heavy separation and cleaning I and II in the step (3) are: the ore feeding amount is 10-20kg / h, the cone surface rotation frequency is 8-12Hz, and the vibration frequency is 11-12Hz.

[0021] Further, the process parameters in the step (4) are: the magnetic field strength of the strong magnetic roughing is 1.4-1.6T, the flushing water amount is 10-12L / min, and the pulsation frequency is 240-260 times / min (preferably 250 times / min); the ore feeding amount in the heavy separation and cleaning I and II is 10-20kg / h, the cone surface rotation frequency is 8-12Hz, and the vibration frequency is 11-13Hz (preferably 12Hz).

[0022] Further, the process parameters in the step (5) are: butyl xanthate 200g / t and No.2 oil 40g / t for the sulfur roughing; butyl xanthate 100-200g / t and No.2 oil 20-40g / t for the sulfur scavenging; water glass 3000-4000g / t, sodium fluorosilicate 1500-2500g / t, salicylhydroxamic acid 700-900g / t, and No.2 oil 20g / t for the rare earth roughing; water glass 1000-2000g / t, sodium fluorosilicate 800-1200g / t, salicylhydroxamic acid 200-400g / t, and No.2 oil 10g / t for the rare earth scavenging I; water glass 600-1000g / t, sodium fluorosilicate 400-600g / t, salicylhydroxamic acid 100-200g / t, and No.2 oil 5g / t for the rare earth scavenging II; and water glass 500g / t, sodium fluorosilicate 300g / t, salicylhydroxamic acid 100g / t, and No.2 oil 5g / t for the rare earth scavenging III.

[0023] Compared with the prior art, the present application has the beneficial technical effects that:

[0024] 1. For the refractory niobium ore with low niobium grade, associated rare earth, pyrite and high gangue content, the present application can promote the effective separation among the niobium minerals, rare earth minerals, pyrite minerals and gangue minerals, and realize the comprehensive recovery of niobium, rare earth and pyrite in the niobium ore.

[0025] 2. The heavy separation process in the present application adopts a new type of micro-fine particle heavy separation equipment, i.e. the suspension vibration cone surface concentrator, which has the advantages of good separation effect on fine particle (-400 mesh) heavy minerals, large treatment capacity, easy parameter adjustment and high efficiency compared with the conventional process using the shaking table.

[0026] 3. The application adopts the process of concentrating and re-concentrating middlings, and regrinds and re-concentrates part of the niobium middlings which are not dissociated, so as to further improve the comprehensive recovery rate of niobium concentrate.

[0027] 4. The application adopts the process of "high-intensity magnetic separation pre-concentration-magnetic separation rough concentrate gravity separation re-concentration-gravity separation concentrate flotation separation", and combines each process link organically according to the properties of low-grade niobium ore, and adopts a unique reagent combination, so as to realize the comprehensive recovery of niobium, rare earth and pyrite in the niobium ore, and has the advantages of remarkable comprehensive recovery effect, simple operation, low cost, small reagent consumption and green environmental protection. BRIEF DESCRIPTION OF DRAWINGS

[0028] The application will be further described below in combination with the description of the accompanying drawings.

[0029] Figure 1 The process flow chart of the beneficiation method for comprehensively recovering niobium, rare earth and pyrite from low-grade niobium ore. DETAILED DESCRIPTION

[0030] Example 1

[0031] The valuable components of the Inner Mongolia Baiyunebo niobium ore sample 1 are mainly Nb2O50.10%, the total amount of rare earth is 8469g / t, Fe is 8.49%, and S is 1.14%; the gangue components are mainly SiO228.01%, CaO 12.96%, and MgO 9.93%. The main valuable metal minerals are columbite, rare earth and pyrite; and the main gangue minerals are mica, dolomite, feldspar and calcite. The separation difficulty lies in the low grade of the raw ore, the high content of gangue, and the deep degree of Fe element impregnation of the gangue minerals.

[0032] The process flow of the application is used for the separation of the Baiyunebo niobium ore sample 1, and the separation is carried out according to the following steps:

[0033] (1) Grinding:

[0034] The ore sample 1 is crushed and ground to a fineness of 87% of -0.038mm, and then adjusted to a pulp concentration of 30%;

[0035] (2) High-intensity magnetic separation pre-concentration:

[0036] The pulp in step (1) is subjected to high-intensity magnetic separation pre-concentration. A vertical ring high-gradient magnetic separator is used for one high-intensity magnetic roughing (1.4T) and two high-intensity magnetic scavenging (scavenging I 1.5T and scavenging II 1.6T). The rinse water amount of the high-intensity magnetic roughing and scavenging is 12L / min, and the pulsation frequency is 250 times / min. The high-intensity magnetic roughing obtains a high-intensity magnetic roughing concentrate, the concentrates of the high-intensity magnetic scavenging I and the high-intensity magnetic scavenging II are combined as middlings 1, and the underflow of the high-intensity magnetic scavenging II is tailings 1.

[0037] (3) Gravity separation re-concentration of the magnetic separation rough concentrate:

[0038] The strong magnetic rough concentrate in step (2) is subjected to two times of cleaning by using the suspension cone concentrator to further enrich the magnetic rough concentrate. The middlings and tailings from the first cleaning by gravity separation are combined as middlings 2. The concentrate and middlings from the second cleaning by gravity separation are combined as gravity separation concentrate 1, and the tailings from the second cleaning by gravity separation are middlings 3.

[0039] In step (3), the feeding amount of the first cleaning by gravity separation is 15 kg / h, the rotating frequency of the cone is 10.1 Hz, and the vibration frequency is 12 Hz; the feeding amount of the second cleaning by gravity separation is 12 kg / h, the rotating frequency of the cone is 10.8 Hz, and the vibration frequency is 12 Hz.

[0040] (4) Middlings concentration and re-cleaning:

[0041] The middlings 1 in step (2) and the middlings 2 and 3 in step (3) are combined, and after being thickened, the mixture is ground to a fineness of 95% passing 0.074 mm. The ground mixture is thickened and subjected to strong magnetic roughing and two times of cleaning by gravity separation (I and II) in sequence. The concentrate from the second cleaning by gravity separation is gravity separation concentrate 2, the underflow from the strong magnetic roughing is tailings 2, the middlings and tailings from the first cleaning by gravity separation are combined as tailings 3, the middlings and tailings from the second cleaning by gravity separation are combined as tailings 4, and the tailings 1 to 4 are combined to obtain total tailings.

[0042] In step (4), the process parameters are as follows: the magnetic field strength of the strong magnetic roughing is 1.4 T, the flushing water amount is 12 L / min, and the pulsation frequency is 250 times / min; the feeding amount of the first cleaning by gravity separation is 15 kg / h, the rotating frequency of the cone is 10.2 Hz, and the vibration frequency is 12 Hz; the feeding amount of the second cleaning by gravity separation is 12 kg / h, the rotating frequency of the cone is 10.8 Hz, and the vibration frequency is 12 Hz.

[0043] (5) Flotation separation of gravity separation concentrate:

[0044] The gravity separation concentrate 1 in step (3) and the gravity separation concentrate 2 in step (4) are combined to obtain a gravity separation concentrate which is a mixed concentrate rich in niobite, rare earth and pyrite. The gravity separation concentrate is subjected to flotation separation. Firstly, the pyrite is floated off by using butyl xanthate as a collector and No. 2 oil as a frother, and the flotation process is one roughing and one scavenging, and the froth from the roughing and scavenging is combined to obtain a pyrite concentrate. Secondly, the rare earth is floated by using water glass and sodium fluosilicate as depressants, salicylhydroxamic acid as a collector, and No. 2 oil as a frother, and the flotation process is one roughing and three scavengings, and the froth from the roughing and scavenging is combined to obtain a rare earth concentrate. Finally, the underflow in the tank is a niobite concentrate.

[0045] The process parameters in step (5) are as follows: butyl xanthate 200 g / t and No. 2 oil 40 g / t are used in the rough separation of sulfur; butyl xanthate 200 g / t and No. 2 oil 40 g / t are used in the scavenging separation of sulfur; water glass 4000 g / t, sodium fluosilicate 2500 g / t, salicylhydroxamic acid 900 g / t and No. 2 oil 20 g / t are used in the rough separation of rare earth; water glass 2000 g / t, sodium fluosilicate 1200 g / t, salicylhydroxamic acid 400 g / t and No. 2 oil 10 g / t are used in the first scavenging separation of rare earth; water glass 1000 g / t, sodium fluosilicate 600 g / t, salicylhydroxamic acid 200 g / t and No. 2 oil 5 g / t are used in the second scavenging separation of rare earth; water glass 500 g / t, sodium fluosilicate 300 g / t, salicylhydroxamic acid 100 g / t and No. 2 oil 5 g / t are used in the third scavenging separation of rare earth.

[0046] After the above embodiment, the comprehensive indexes of beneficiation obtained from the low-grade niobium ore sample 1 of Baiyunebo are as follows: the grade of niobium concentrate Nb2O5 is 8.03%, the recovery rate of niobium is 19.23%; the grade of rare earth is 50.41%, the recovery rate is 36.27%; the grade of S in pyrite concentrate is 43.85%, the recovery rate of S is 20.49%.

[0047] Example 2

[0048] The valuable components in the niobium ore sample 2 of Baiyunebo are mainly Nb2O50.093%, the total amount of rare earth is 8123 g / t, Fe is 8.73%, and S is 1.21%; the gangue components are mainly SiO228.07%, CaO 13.05% and MgO 9.35%; the main valuable metal minerals are columbite, rare earth minerals and pyrite; and the main gangue minerals are mica, dolomite, feldspar and calcite. The separation difficulty of the niobium ore sample 2 of Baiyunebo lies in that the grade of the raw ore is low, the content of gangue is high, the columbite is in a micro-fine-grained disseminated distribution, and the intergrowth relationship with mica is relatively close, and the single liberation degree is poor.

[0049] The niobium ore sample 2 of Baiyunebo is separated by the process flow of the present application according to the following steps:

[0050] (1) Grinding: the raw ore of sample 2 is crushed and ground to a fineness of 86% of -0.038 mm, and then adjusted to a pulp concentration of 27%;

[0051] (2) Pre-concentration by high-intensity magnetic separation:

[0052] The pulp in step (1) is subjected to once rough high-intensity magnetic separation (1.4T) and twice scavenging high-intensity magnetic separation (scavenging I 1.5T and scavenging II 1.5T) by a vertical ring high-gradient magnetic separator, the washing water amount of the rough and scavenging high-intensity magnetic separation is 12 L / min, and the pulsation frequency is 250 times / min. The purpose of the high-intensity magnetic separation is to pre-concentrate the niobium ore. The rough high-intensity magnetic separation obtains a rough high-intensity magnetic concentrate, the concentrates of the high-intensity magnetic scavenging I and the high-intensity magnetic scavenging II are combined as middlings 1, and the underflow of the high-intensity magnetic scavenging II is tailings 1.

[0053] (3) Rough concentrate of magnetic separation is enriched by gravity separation:

[0054] Step (3) of this embodiment is the same as step (3) of embodiment 1.

[0055] (4) Concentration of middlings:

[0056] Middlings 1 in step (2) and middlings 2 and 3 in step (3) are combined, and after being conditioned, the combined middlings are ground to a fineness of 93% passing 0.038 mm; the ground middlings are conditioned and subjected to rough magnetic separation, and then subjected to two times of gravity separation cleaning in a suspension cone separator; the concentrate obtained from the second gravity separation cleaning is gravity separation concentrate 2, the underflow of the rough magnetic separation is tailings 2, the middlings and tailings of the first gravity separation cleaning are combined to form tailings 3, the middlings and tailings of the second gravity separation cleaning are combined to form tailings 4, and the tailings 1 to 4 are combined to form total tailings.

[0057] In step (4), the process parameters are: the magnetic field strength of the rough magnetic separation is 1.5 T, the flushing water amount is 12 L / min, and the pulsation frequency is 250 times / min; the feed amount of the first gravity separation cleaning is 15 kg / h, the rotation frequency of the cone is 10.3 Hz, and the vibration frequency is 11.6 Hz; the feed amount of the second gravity separation cleaning is 12 kg / h, the rotation frequency of the cone is 10.8 Hz, and the vibration frequency is 11.8 Hz.

[0058] (5) Flotation separation of gravity separation concentrate:

[0059] The gravity separation concentrate 1 in step (3) and the gravity separation concentrate 2 in step (4) are combined to obtain a gravity separation concentrate, which is a mixed concentrate rich in niobite, rare earth and pyrite. The gravity separation concentrate is subjected to flotation separation, first, pyrite is floated off: butyl xanthate is used as a collector, No. 2 oil is used as a frother, the flotation process is one roughing and one scavenging, and the froth of the roughing and the scavenging is combined to obtain a pyrite concentrate; second, rare earth is floated: water glass and sodium fluosilicate are used as depressants, salicylhydroxamic acid is used as a collector, and No. 2 oil is used as a frother, the flotation process is one roughing and three scavengings, and the froth of the roughing and the scavenging is combined to obtain a rare earth concentrate; finally, the underflow in the tank is a niobium concentrate.

[0060] The process parameters in step (5) are as follows: butyl xanthate 200 g / t and No. 2 oil 40 g / t are used in the rough separation of sulfur; butyl xanthate 200 g / t and No. 2 oil 40 g / t are used in the scavenging separation of sulfur; water glass 3500 g / t, sodium fluosilicate 2000 g / t, salicylhydroxamic acid 800 g / t and No. 2 oil 20 g / t are used in the rough separation of rare earth; water glass 1500 g / t, sodium fluosilicate 1000 g / t, salicylhydroxamic acid 300 g / t and No. 2 oil 10 g / t are used in the first scavenging separation of rare earth; water glass 800 g / t, sodium fluosilicate 500 g / t, salicylhydroxamic acid 200 g / t and No. 2 oil 5 g / t are used in the second scavenging separation of rare earth; water glass 500 g / t, sodium fluosilicate 300 g / t, salicylhydroxamic acid 100 g / t and No. 2 oil 5 g / t are used in the third scavenging separation of rare earth.

[0061] After the above embodiment, the comprehensive indexes of the beneficiation of the Baiyunebo low-grade niobium ore sample 2 are as follows: the grade of niobium concentrate (Nb2O5) is 8.32%, the recovery rate of niobium is 19.47%; the grade of rare earth is 52.36%, the recovery rate is 38.32%; the grade of S in the pyrite concentrate is 44.41%, the recovery rate of S is 20.93%.

[0062] Example 3

[0063] The Baiyunebo niobium ore sample 3 mainly contains Nb2O50.121%, the total amount of rare earth is 7869 g / t, Fe 9.03%, S 1.29%, SiO227.12%, CaO 11.32%, and MgO 9.31%. The main valuable metal minerals are niobite, rare earth and pyrite; the main gangue minerals are mica, dolomite, feldspar and calcite. The characteristics of the Baiyunebo niobium ore sample 3 are low grade of niobium, fine dissemination size of niobium minerals and poor liberation degree of single body. It is difficult to separate the niobium minerals from the gangue minerals by using the conventional beneficiation process.

[0064] The Baiyunebo niobium ore sample 3 is separated by using the process flow of the present application according to the following steps:

[0065] (1) Grinding: the ore sample 3 is crushed and ground to a fineness of 87% of -0.038 mm, and then adjusted to a pulp concentration of 25%;

[0066] (2) Pre-concentration by high intensity magnetic separation:

[0067] The pulp in step (1) is subjected to pre-concentration of niobium ore by high intensity magnetic separation. A vertical ring high gradient magnetic separator is used for one high intensity rough magnetic separation (1.4T) and two high intensity scavenging separations (scavenging I 1.6T and scavenging II 1.6T). The washing water amount of the high intensity rough magnetic separation and the scavenging separations is 12 L / min, and the pulsation frequency is 250 times / min. The high intensity rough magnetic separation produces a high intensity rough magnetic concentrate, the concentrates of the high intensity scavenging I and the high intensity scavenging II are combined as middlings 1, and the underflow of the high intensity scavenging II is tailings 1.

[0068] (3) Re-enrichment of the rough magnetic concentrate by gravity separation:

[0069] The rough magnetic concentrate in step (2) is subjected to two times of gravity separation (I and II) by using a suspension cone separator to further enrich the rough magnetic concentrate. The middlings and tailings from the gravity separation I are combined as middlings 2. The concentrate and middlings from the gravity separation II are combined as gravity concentrate 1, and the tailings from the gravity separation II are middlings 3.

[0070] In step (3), the feed quantity of the gravity separation I is 13 kg / h, the cone rotation frequency is 10.1 Hz, and the vibration frequency is 11.6 Hz. The feed quantity of the gravity separation II is 10 kg / h, the cone rotation frequency is 10.1 Hz, and the vibration frequency is 11.5 Hz.

[0071] (4) Concentration of the middlings for re-separation:

[0072] The middlings 1 in step (2) and the middlings 2 and 3 in step (3) are combined, and after being conditioned, the combined middlings are re-ground to a fineness of 90% passing -0.038 mm. The re-ground middlings are conditioned and subjected to rough magnetic separation and two times of gravity separation by the suspension cone separator. The underflow from the rough magnetic separation is tailings 2, the concentrate from the gravity separation II is gravity concentrate 2, the middlings and tailings from the gravity separation I are combined as tailings 3, the middlings and tailings from the gravity separation II are combined as tailings 4, and the tailings 1 to 4 are combined to obtain the total tailings.

[0073] In step (4), the process parameters are as follows: the magnetic field strength of the rough magnetic separation is 1.6 T, the flushing water quantity is 12 L / min, and the pulsation frequency is 250 times / min; the feed quantity of the gravity separation I is 12 kg / h, the cone rotation frequency is 10.1 Hz, and the vibration frequency is 11.7 Hz; and the feed quantity of the gravity separation II is 12 kg / h, the cone rotation frequency is 10.5 Hz, and the vibration frequency is 11.5 Hz.

[0074] (5) Flotation separation of the gravity concentrate:

[0075] The gravity concentrate 1 in step (3) and the gravity concentrate 2 in step (4) are combined to obtain a gravity concentrate which is a mixed concentrate rich in niobite, rare earth and pyrite. The gravity concentrate is subjected to flotation separation. Firstly, the flotation of pyrite is carried out by using butyl xanthate as the collector and No. 2 oil as the frother, and the flotation process is one roughing and one scavenging. The froth from the roughing and scavenging is combined to obtain a pyrite concentrate. Secondly, the flotation of rare earth is carried out by using water glass and sodium fluosilicate as the depressants and salicylhydroxamic acid as the collector, and No. 2 oil as the frother, and the flotation process is one roughing and three scavengings. The froth from the roughing and scavenging is combined to obtain a rare earth concentrate. Finally, the underflow in the tank is a niobite concentrate.

[0076] The process parameters in step (5) are as follows: butyl xanthate 200 g / t and No. 2 oil 40 g / t for sulfur roughing; butyl xanthate 100 g / t and No. 2 oil 20 g / t for sulfur scavenging; water glass 3000 g / t, sodium fluosilicate 1500 g / t, salicylhydroxamic acid 700 g / t and No. 2 oil 20 g / t for rare earth roughing; water glass 1000 g / t, sodium fluosilicate 800 g / t, salicylhydroxamic acid 200 g / t and No. 2 oil 10 g / t for rare earth scavenging I; water glass 600 g / t, sodium fluosilicate 400 g / t, salicylhydroxamic acid 100 g / t and No. 2 oil 5 g / t for rare earth scavenging II; and water glass 500 g / t, sodium fluosilicate 300 g / t, salicylhydroxamic acid 100 g / t and No. 2 oil 5 g / t for rare earth scavenging III.

[0077] After the above embodiment, the comprehensive indexes of the beneficiation obtained from the low-grade niobium ore sample 3 of Baiyunebo are as follows: the grade of niobium concentrate (Nb2O5) is 8.43%, the recovery rate of niobium is 19.82%; the grade of rare earth is 54.8%, the recovery rate is 39.83%; the grade of S in the pyrite concentrate is 44.57%, and the recovery rate of S is 21.35%.

[0078] The above-described embodiments are only used to describe the preferred modes of the present application, and do not limit the scope of the present application. Without departing from the design spirit of the present application, various modifications and improvements of the technical solutions of the present application made by those skilled in the art shall fall within the protection scope determined by the claims of the present application.

Claims

1. A mineral processing method for comprehensively recovering niobium, rare earth elements, and pyrite from low-grade niobium ore, characterized in that: Includes the following steps: (1) Grinding: The niobium ore is crushed and ground to a fineness of -0.038 mm (85%–87%), and then the slurry concentration is adjusted to 25–30%. (2) Strong magnetic separation pre-enrichment: For the slurry in step (1), a vertical ring high gradient magnetic separator is used to perform one strong magnetic roughing and two strong magnetic scavenging to pre-enrich the valuable components in the niobium ore; Strong magnetic roughing yields strong magnetic roughing concentrate, the concentrates from strong magnetic scavenging I and strong magnetic scavenging II are combined into middlings 1, and the underflow from strong magnetic scavenging II is tailings 1; (3) Magnetic separation rougher and concentrate gravity separation and re-enrichment: For the strong magnetic roughing concentrate in step (2), a gravity separation equipment, a suspended cone surface concentrator, is used for two fine separations to further enrich the magnetic roughing concentrate; the middlings and tailings of gravity separation I are combined into middlings 2, the concentrate and middlings obtained from gravity separation II are combined into gravity concentrate 1, and the tailings of gravity separation II are middlings 3. (4) Centralized reprocessing of middlings: The middlings 1 from step (2) and middlings 2 and 3 from step (3) are combined, slurry is prepared, and then ground to a fineness of -0.038 mm 90% to 95%. The slurry after regrinding is then prepared and subjected to two gravity separation processes: strong magnetic roughing and suspension cone concentrator. The underflow from strong magnetic roughing is tailings 2, and the concentrate obtained from gravity separation process II is gravity concentrate 2. The middlings and tailings from gravity separation process I are combined to form tailings 3, and the middlings and tailings from gravity separation process II are combined to form tailings 4. The total tailings are obtained by combining tailings 1 to tailings 4. (5) Gravity concentrate flotation separation: The gravity concentrate 1 from step (3) and the gravity concentrate 2 from step (4) are combined to obtain a gravity concentrate, which is a mixed concentrate rich in columbite, rare earth and pyrite. The gravity concentrate is adjusted to a slurry with a concentration of 25-35% and then subjected to flotation separation. First, desulfurization is carried out by flotation: butyl xanthate is used as the collector, No. 2 oil is used as the frother, and the flotation process consists of one roughing and one scavenging. The froth from the roughing and scavenging processes is combined to obtain pyrite concentrate. Second, rare earth flotation is carried out: water glass and sodium fluorosilicate are used as depressants, salicylhydroxyxamic acid is used as the collector, and No. 2 oil is used as the frother, and the flotation process consists of one roughing and three scavenging processes. The froth from the roughing and scavenging processes is combined to obtain rare earth concentrate. Finally, the underflow in the tank is niobium concentrate.

2. The beneficiation method for comprehensively recovering niobium, rare earth elements, and pyrite from low-grade niobium ore according to claim 1, characterized in that: In step (1), the niobium grade in the raw ore is 0.08-0.12%, and the main niobium-bearing mineral is columbite, which is finely embedded and associated with rare earth, pyrite, a small amount of ilmenite and gangue minerals; the main gangue minerals are at least mica, dolomite, feldspar and calcite.

3. The beneficiation method for comprehensively recovering niobium, rare earth elements, and pyrite from low-grade niobium ore according to claim 1, characterized in that: The process parameters in step (2) are as follows: the magnetic field strength of the strong magnetic roughing is 1.4T, the magnetic field strength of strong magnetic sweeping I and II is 1.4 to 1.6T; the rinsing water volume of strong magnetic roughing and sweeping is 10 to 12L / min, and the number of pulses is 240 to 260 times / min.

4. The beneficiation method for comprehensively recovering niobium, rare earth elements, and pyrite from low-grade niobium ore according to claim 1, characterized in that: The process parameters for gravity separation I and II in step (3) are: feed rate 10-20 kg / h, cone rotation frequency 8-12 Hz, and vibration frequency 11-12 Hz.

5. The beneficiation method for comprehensively recovering niobium, rare earth elements, and pyrite from low-grade niobium ore according to claim 1, characterized in that: The process parameters in step (4) are as follows: the magnetic field strength of the strong magnetic roughing is 1.4 to 1.6T, the washing water volume is 10 to 12L / min, and the number of pulses is 240 to 260 times / min; the feed rate in gravity separation I and II is 10 to 20kg / h, the cone rotation frequency is 8Hz to 12Hz, and the vibration frequency is 11 to 13Hz.

6. The beneficiation method for comprehensively recovering niobium, rare earth elements, and pyrite from low-grade niobium ore according to claim 1, characterized in that: The process parameters in step (5) are as follows: Sulfur roughing: butyl xanthate 200 g / t, No. 2 oil 40 g / t; Sulfur scavenging: butyl xanthate 100-200 g / t, No. 2 oil 20-40 g / t; Rare earth roughing: water glass 3000-4000 g / t, sodium fluorosilicate 1500-2500 g / t, salicylic acid 700-900 g / t, No. 2 oil 20 g / t; Rare earth scavenging I: water glass 1000-2000 g / t. g / t, sodium fluorosilicate 800~1200g / t, salicylic acid 200~400g / t, No. 2 oil 10g / t; Rare earth scavenging II: water glass 600~1000g / t, sodium fluorosilicate 400~600g / t, salicylic acid 100~200g / t, No. 2 oil 5g / t; Rare earth scavenging III: water glass 500g / t, sodium fluorosilicate 300g / t, salicylic acid 100g / t, No. 2 oil 5g / t.

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