A flotation method for niobium-containing minerals

Abstract

The present invention relates to a flotation method for niobium-containing minerals, belonging to the field of mineral processing technology. The method comprises crushing, grinding, and slurrying the niobium-containing ore, subjecting the resulting slurry to weak magnetic treatment to remove strongly magnetic minerals, adjusting the pH of the magnetic separation tailings, and then adding flotation reagents including iron mineral inhibitors and amine collectors to carry out silicon-niobium mixed flotation. The resulting silicon-niobium mixed concentrate is pH-adjusted, and then adding flotation reagents including hydroxamic acid metal organic complex collectors and siliceous mineral inhibitors to carry out silicon-niobium separation flotation to obtain a niobium concentrate. The method utilizes step-by-step flotation to first remove iron gangue minerals using an amine collector, and then separate silicon using a hydroxamic acid metal organic complex collector, thereby achieving efficient enrichment of niobium minerals. This method avoids the strong magnetic de-ironization step, simplifies the process, and reduces the loss rate of niobium ore.

Description

Technical Field

[0001] The present invention relates to a flotation method for niobium-containing minerals, in particular to a step-by-step flotation enrichment method for niobium-containing minerals, and belongs to the technical field of mineral processing. Background Art

[0002] Niobium is an emerging mineral resource. In the steel industry, adding just 0.03% to 0.05% niobium can increase steel's yield strength by over 30%, significantly reducing steelmaking costs. Due to its high-temperature resistance, corrosion resistance, wear resistance, and excellent thermal conductivity, niobium is widely used in aerospace, superconducting materials, medicine, and other national technological fields.

[0003] Niobium deposits are mainly divided into carbonate-type niobium deposits, alkaline rock-type niobium-tantalum deposits, rare metal granite-type niobium-tantalum deposits, and pegmatite-type niobium-tantalum deposits. The main mineral types are pyrochlore, columbite, and columbite-tantalum ore. Most of their gangue minerals are ferrous gangue minerals (magnetite, hematite, ilmenite, limonite, etc.) and siliceous gangue minerals (quartz, mica, chlorite, feldspar, kaolin, etc.).

[0004] Currently exploitable niobium ore resources in China are of low grade, with complex composition and fine particle size, making separation difficult. Foreign niobium ore is mostly composed of carbonate-type pyrochlore, which is high-grade and easy to separate. A common separation process involves first using a fatty acid collector, suppressing the pyrochlore with the addition of a conditioning agent, removing the carbonate minerals by reverse flotation, and then adding a cationic collector to flotate the pyrochlore. However, this still presents drawbacks such as a complex process and high reagent consumption.

[0005] Currently, there are reports on the use of hydroxamic acid collectors in niobium ore flotation. Hydroxamic acid collectors exhibit excellent capture and selectivity for niobium ore. However, hydroxamic acid collectors are sensitive to iron components. Using hydroxamic acid collectors alone can result in the inclusion of large amounts of uncontrollable iron impurities in niobium concentrate, affecting the flotation performance of niobium ore. Currently, niobium concentrate is primarily recovered through iron-niobium co-flotation. For example, a Chinese patent application (publication number: CN118268138A) discloses a method for co-enriching iron and niobium resources from rare earth tailings. This method involves flotation desulfurization of the rare earth tailings, adjusting the slurry pH to alkaline, and using a metal-organic complex (formed by coordination of a divalent or higher metal ion with a hydroxamic acid organic ligand) as a co-flotation collector for iron and niobium minerals. Gangue mineral depressants are also used for flotation separation, resulting in a mixed iron-niobium concentrate. As for the recovery of niobium resources in iron-niobium mixed concentrate, the main methods currently used are alkali decomposition, acid decomposition and chlorination roasting. These technologies have technical problems such as low niobium yield, large acid and alkali consumption, high energy consumption and complex processes. Summary of the Invention

[0006] In view of the difficulties in the current niobium-containing mineral beneficiation process, such as lengthy procedures, complex processes, high costs, and low niobium ore recovery, the present invention aims to provide a flotation method for niobium-containing minerals. The method first utilizes the weak capture of amine collectors for ferrous minerals and the strong capture of siliceous minerals and niobium minerals to achieve pre-co-enrichment of siliceous and niobium minerals, and then utilizes the weak capture of siliceous gangue minerals and the strong capture of niobium minerals by hydroxamic acid metal organic complex collectors to achieve efficient separation of siliceous and niobium minerals. The method has a high niobium yield, low reagent consumption, low energy consumption, a simple process, and is conducive to large-scale promotion and application.

[0007] In order to achieve the above technical objectives, the present invention provides a flotation method for niobium-containing minerals, which comprises the following steps:

[0008] 1) Crushing, grinding and slurrying the niobium-containing ore to obtain slurry;

[0009] 2) subjecting the slurry to weak magnetic treatment to remove strongly magnetic minerals to obtain magnetically separated tailings;

[0010] 3) After adjusting the pH of the magnetic separation tailings, flotation reagents including iron mineral inhibitors and amine collectors are added to carry out silicon-niobium mixed flotation to obtain a silicon-niobium mixed concentrate;

[0011] 4) After adjusting the pH of the silicon-niobium mixed concentrate, flotation reagents including a hydroxamic acid metal organic complex collector and a siliceous mineral inhibitor are added to carry out silicon-niobium separation and flotation to obtain a niobium concentrate.

[0012] The flotation method for niobium-containing minerals provided by the present invention is mainly aimed at siliceous minerals, ferrous minerals and niobium minerals among niobium-containing minerals. However, it is currently difficult to separate siliceous minerals, ferrous minerals and niobium minerals. A large number of studies have shown that both amine collectors and hydroxamic acid collectors can be used as niobium ore flotation collectors. Although a single hydroxamic acid collector shows excellent capture and selectivity for niobium minerals, it is relatively sensitive to ferrous minerals and usually enriches ferrous minerals and niobium minerals in the form of a mixed concentrate, making subsequent separation of ferrous minerals and niobium minerals difficult. A single amine collector shows good capture of niobium minerals and weak capture capacity for ferrous minerals, but is relatively sensitive to ore slime and siliceous minerals, making it difficult to separate siliceous minerals from niobium minerals. The present invention aims at the characteristics of current niobium-containing minerals and the defects of the existing flotation separation process between siliceous minerals, iron minerals and niobium minerals. The present invention designs a reasonable step-by-step flotation enrichment method for niobium ore. The method is to first perform weak magnetic separation on niobium minerals to remove strongly magnetic gangue minerals including magnetite, and non-magnetic minerals are preferentially pre-enriched using amine collectors. By utilizing the characteristics of amine collectors that have strong capture properties for niobium minerals and siliceous minerals but are insensitive to iron minerals, iron minerals can be preferentially removed, while siliceous minerals and niobium minerals are co-enriched. The silicon-niobium mixed concentrate is then pre-enriched using hydroxamic acid metal organic solvents. The invention separates niobium from tantalum by using the organic metal complex, and utilizes the characteristics of hydroxamic acid metal organic complex's weak capture of siliceous minerals and strong capture of niobium minerals to remove siliceous minerals and achieve further enrichment of niobium ore. In summary, the process of the invention combines the capture characteristics of hydroxamic acid metal organic complex collector and amine collector for silicon-containing minerals, iron-containing minerals and niobium-containing minerals, solves the technical problem that it is difficult to separate niobium, iron and silicon by using a single amine collector or a hydroxamic acid metal organic complex collector, simplifies the process flow, reduces the loss rate of niobium ore, and effectively realizes the resource utilization of such niobium ore.

[0013] As a preferred solution, the main minerals of the niobium ore are siliceous minerals, iron minerals and niobium minerals; the siliceous minerals include at least one of quartz, mica, feldspar, kaolin and chlorite.

[0014] As a preferred solution, the iron mineral includes at least one of magnetite, hematite, titanomagnetite, ilmenite, hematite, limonite, siderite and ankerite.

[0015] As a preferred solution, the niobium mineral includes at least one of pyrochlore, niobite, calcite, and niobium ferrorutile.

[0016] As a preferred solution, the grinding is to achieve a suitable particle size so that the mass proportion of the -200 mesh particle size reaches more than 80%, thereby achieving sufficient monomer dissociation of the niobium minerals and facilitating subsequent flotation separation.

[0017] As a preferred solution, the slurry adjustment is to meet the slurry mass concentration of 30% to 40%.

[0018] As a preferred solution, the weak magnetic treatment uses a magnetic field strength of 1000-2000 Gs. Through weak magnetic treatment, magnetite, ilmenite, hematite, etc., which have a high proportion and strong magnetism, can be preferentially removed, reducing the difficulty of subsequent flotation separation.

[0019] As a preferred solution, in step 3), the pH is adjusted to 2.5-4. Acid, such as hydrochloric acid, is used to adjust the pH. Adjusting the pH to a weakly acidic state provides a favorable pH environment for silicon-niobium mixed flotation.

[0020] As a preferred embodiment, the silicon-niobium mixed flotation process includes one roughing stage, one to three cleaning stages, and one to two scavenging stages. As a more preferred embodiment, the roughing agent system includes 300-800 g / t of iron mineral depressant and 1000-2000 g / t of amine collector. As a more preferred embodiment, the cleaning agent system includes only iron mineral depressant, with the agent dosage being halved. As a more preferred embodiment, the scavenging agent system includes only amine collector, with the agent dosage being halved. Under these preferred flotation conditions, iron minerals can be efficiently removed from niobium-containing minerals, while silicate and niobium minerals are efficiently enriched, resulting in a silicon-niobium mixed concentrate.

[0021] As a preferred embodiment, the amine collector includes at least one of tallow diamine, dodecyl acetic acid amine, and an aliphatic diamine having 10 to 20 carbon atoms. Preferred amine collectors are highly reactive toward niobium minerals, sensitive to silicon, and less reactive toward ferrous minerals. Amine collectors can achieve efficient enrichment of both siliceous and niobium minerals. Tallow diamine is a further preferred amine collector.

[0022] As a preferred embodiment, the iron mineral inhibitor includes at least one of fluorosilicic acid, sodium fluorosilicate, oxalic acid, and sodium humate. The preferred iron mineral inhibitor selectively acts on the ferric and ferrous ions on the surface of iron minerals, thereby hydrophilizing the surface and inhibiting the flotation of iron minerals. The use of an iron mineral inhibitor can improve the removal efficiency of iron minerals.

[0023] As a preferred embodiment, in step 4), the pH is adjusted to 6-8. Alkaline compounds such as NaCO and NaOH are used to adjust the pH. Under different pH conditions, the chemical structure of the hydroxamic acid metal organic complex formed by the assembly of divalent or higher-valent metal ions with the hydroxamic acid ligand varies, resulting in different capture capacities. The preferred pH range facilitates the interaction of the hydroxamic acid metal organic complex with the niobium mineral surface, enhancing the flotation separation of the niobium mineral.

[0024] As a preferred embodiment, the silicon-niobium separation flotation process includes one roughing stage, three to six cleaning stages, and one to two scavenging stages. As a more preferred embodiment, the roughing agent system includes: 30-100 g / t of siliceous mineral depressant, 300-800 g / t of hydroxamic acid metal organic complex collector, and 5-30 g / t of frother. As a more preferred embodiment, the cleaning agent system includes only siliceous mineral depressant, with the agent dosage gradually reduced by half. As a more preferred embodiment, the scavenging agent system includes only hydroxamic acid metal organic complex collector, with the agent dosage gradually reduced by half. Under these optimal flotation conditions, siliceous minerals can be efficiently removed from niobium ore, while niobium ore is efficiently enriched to produce niobium concentrate.

[0025] As a more preferred solution, the hydroxamic acid metal organic complex collector is composed of at least one of benzohydroxamic acid, salicylic hydroxamic acid, and an alkyl hydroxamic acid having 5 to 9 carbon atoms and Pb 2+ 、Zn 2+ 、Al 3+ 、Cu 2+ 、Fe 2+ 、Fe 3+ At least one of the hydroxamic acid ligands is assembled in a mass ratio of 0.5:1 to 1:3. The template effect of high-valent metal ions is utilized to regulate the assembly of hydroxamic acid ligands, pre-assembling hydroxamic acid metal organic complexes with a deionized hydration layer structure. These complexes possess unique crystal chemical and surface physicochemical properties, exhibiting superior capture capacity and selectivity. In particular, micelles with specific structures and capture capacities are formed by assembling high-valent metal ions such as lead, zinc, aluminum, copper, and iron ions with hydroxamic acid ligands. These micelles exhibit high selectivity for niobium minerals, facilitating their enrichment. Furthermore, the hydroxamic acid metal organic complexes generated at different molar ratios of high-valent metal ions to hydroxamic acid ligands exhibit varying capture capacities for minerals. At the optimal ratio, the hydroxamic acid metal organic complexes exhibit enhanced capture capacity and selectivity for niobium-containing minerals.

[0026] As a preferred embodiment, the siliceous mineral inhibitor includes at least one of fluorosilicic acid, sodium hexametaphosphate, carboxymethyl cellulose, oxalic acid, water glass, salinized water glass, and sodium fluorosilicate. Hydroxamic acid metal organic complexes, which have high selectivity for niobium minerals and strong capture capacity, when used in conjunction with suitable siliceous mineral inhibitors, can improve the removal efficiency of siliceous minerals.

[0027] As a preferred solution, the foaming agent includes BK205.

[0028] Compared with the existing technology, the technical solution of the present invention brings the following beneficial technical effects:

[0029] (1) The present invention makes full use of the collection characteristics of amine collectors for iron minerals, siliceous minerals and niobium minerals, eliminates the early strong magnetic and desiliconization processes, realizes the separation of iron minerals, and solves the technical problem of the difficulty in separating iron and niobium minerals in the hydroxamic acid metal ion complex niobium ore collection system.

[0030] (2) The present invention makes full use of the selectivity and collecting properties of hydroxamic acid metal organic complex collectors for siliceous minerals and niobium minerals, realizes the separation of gangue minerals mainly composed of siliceous minerals and niobium minerals, and solves the problem that amine collectors are difficult to separate siliceous and niobium minerals.

[0031] (3) The present invention takes into account the composition characteristics of niobium-containing minerals. It first uses amine collectors to achieve flotation de-ironization and achieve co-enrichment of silicon and niobium, and then uses hydroxamic acid metal ion complex collectors to flotation de-siliconization to enhance the recovery of niobium concentrate. This process replaces the complex high-intensity magnetic separation and desiliconization operations at the front end of the traditional niobium flotation process, eliminates the large amount of niobium loss caused by the multi-stage high-intensity magnetic separation-desiliconization operation, simplifies the niobium ore separation process, and improves the comprehensive recovery rate of niobium ore. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a flow chart of the flotation process for niobium-containing minerals provided by the present invention. DETAILED DESCRIPTION

[0033] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the following specific embodiments are intended to further illustrate the contents of the present invention rather than to limit the scope of protection of the claims.

[0034] Example 1

[0035] A step-by-step flotation enrichment experiment was conducted using niobium-containing phosphate tailings from a Brazilian concentrator. The main components of this phosphate tailings are magnetite-maghemite, hematite, limonite, ilmenite, quartz, apatite, barite, magnesian serpentine, mica, barium-strontium pyrochlore, and columbite. Iron-containing minerals primarily consist of magnetite-maghemite, accounting for approximately 6%, while limonite, hematite, and ilmenite together account for approximately 35%. Silicon-containing minerals primarily consist of quartz and mica, accounting for approximately 41%. Niobium-containing minerals primarily consist of barium-strontium pyrochlore, accounting for approximately 0.74%. The Nb2O5 content of this tailings is approximately 0.76%.

[0036] (1) The tailings have a -200 mesh size of about 52%. The tailings were ground in a ball mill for 3 minutes until the -200 mesh size reached 86%. Water was then added to adjust the slurry concentration to 30%.

[0037] (2) Use a weak magnet of 2000 Gs to remove strongly magnetic minerals;

[0038] (3) The product after strong magnetic removal is subjected to silicon niobium pre-enrichment flotation: The silicon niobium pre-enrichment process is as follows: hydrochloric acid is added as a pH adjuster to adjust the pH of the pulp to 4.5, stirring and slurrying for 3 minutes, then 500g / t of fluorosilicic acid is added as an inhibitor, stirring and slurrying for 3 minutes, and finally 1500g / t of tallow diamine is added as a collector, slurrying for 3 minutes, and roughing operation is carried out; the coarse concentrate is subjected to three concentration operations to gradually lower the pH to 2.5, and inhibitors are added and the amount is gradually reduced by half; the coarse tailings are subjected to one scavenging operation and only collectors are added and the amount is reduced by half; the silicon niobium pre-enrichment concentrate obtained has an Nb2O5 grade of 4.39% and a recovery rate of 70.21%, an Fe2O3 grade of 3.2%, and a silicon grade of 35.65%.

[0039] (4) Silicon niobium separation and flotation were carried out on the silicon niobium pre-enriched concentrate: the silicon niobium separation process was as follows: sodium hydroxide was added as a pH adjuster to adjust the pH of the pulp to 8, the pulp was stirred for 3 minutes, 50 g / t of fluorosilicic acid was added as an inhibitor, the pulp was stirred for 3 minutes, 500 g / t of benzohydroxamic acid-lead metal ion complex collector (the mass ratio of benzohydroxamic acid to lead was 1:1) was added, 10 g / t of BK205 was added as a frother, and roughing operation was carried out; in the concentration operation of silicon niobium separation, only inhibitors were added and the amount was gradually reduced by half; in the concentration operation of silicon niobium separation, only collectors were added and the amount was gradually reduced by half; on this basis, one roughing, four concentrations and one scavenging were carried out, and finally a niobium concentrate with a Nb2O5 grade of 28.75% and a recovery rate of 50.42% was obtained.

[0040] Example 2

[0041] The same niobium-containing phosphorus tailings from a Brazilian concentrator as in Example 1 were used as the research object, and a step-by-step flotation enrichment experiment was conducted on it.

[0042] (1) The tailings have a -200 mesh ratio of about 52%. The ball mill is used to grind the tailings for 3 minutes until the -200 mesh ratio reaches 86%. Then water is added to adjust the pulp to a pulp mass concentration of 30%;

[0043] (2) Use a weak magnet of 2000 Gs to remove strongly magnetic minerals;

[0044] (3) The product after strong magnetic removal is subjected to silicon niobium pre-enrichment flotation: The silicon niobium pre-enrichment process is as follows: hydrochloric acid is added as a pH adjuster to adjust the pH of the pulp to 4.5, stirring and slurrying for 3 minutes, then 600g / t of fluorosilicic acid is added as an inhibitor, stirring and slurrying for 3 minutes, and finally 1300g / t of dodecyl acetic acid amide is added as a collector, slurrying for 3 minutes, and roughing operation is carried out; the coarse concentrate is subjected to three concentration operations to gradually lower the pH to 2.5, and inhibitors are added and the amount is gradually reduced by half; the coarse tailings are subjected to one scavenging operation and only collectors are added and the amount is reduced by half; the silicon niobium pre-enrichment concentrate obtained has an Nb2O5 grade of 4.05% and a recovery rate of 66.85%, an Fe2O3 grade of 3.6%, and a silicon grade of 37.21%.

[0045] (4) Silicon niobium separation flotation was carried out on the silicon niobium pre-enriched concentrate: the silicon niobium separation process was as follows: sodium hydroxide was added as a pH adjuster to adjust the pH of the pulp to 8, the pulp was stirred for 3 minutes, 60 g / t of fluorosilicic acid was added as an inhibitor, the pulp was stirred for 3 minutes, 550 g / t of benzohydroxamic acid-lead metal ion complex collector (the mass ratio of benzohydroxamic acid to lead was 1:1) was added, 12 g / t of BK205 was added as a frother, and roughing operation was carried out; in the concentration operation of silicon niobium separation, only inhibitors were added and the amount was gradually reduced by half; in the concentration operation of silicon niobium separation, only collectors were added and the amount was gradually reduced by half; on this basis, one roughing, four concentrations and one scavenging were carried out, and finally a niobium concentrate with a Nb2O5 grade of 26.53% and a recovery rate of 47.28% was obtained.

[0046] Example 3

[0047] The same niobium-containing phosphorus tailings from a Brazilian concentrator as in Example 1 were used as the research object, and a step-by-step flotation enrichment experiment was conducted on it.

[0048] (1) The tailings have a -200 mesh ratio of about 52%. The ball mill is used to grind the tailings for 3 minutes until the -200 mesh ratio reaches 86%. Then water is added to adjust the pulp to a pulp mass concentration of 30%;

[0049] (2) Use a weak magnet of 2000 Gs to remove strongly magnetic minerals;

[0050] (3) The product after strong magnetic removal is subjected to silicon niobium pre-enrichment flotation: The silicon niobium pre-enrichment process is as follows: hydrochloric acid is added as a pH adjuster to adjust the pH of the pulp to 4.5, stirring and slurrying for 3 minutes, then 550g / t of fluorosilicic acid is added as an inhibitor, stirring and slurrying for 3 minutes, and finally 1400g / t of dodecyl diamine is added as a collector, slurrying for 3 minutes, and roughing operation is carried out; the coarse concentrate is subjected to three concentration operations to gradually lower the pH to 2.5, and inhibitors are added and the amount is gradually reduced by half; the coarse tailings are subjected to one scavenging operation and only collectors are added and the amount is reduced by half; the silicon niobium pre-enrichment concentrate obtained has an Nb2O5 grade of 4.20% and a recovery rate of 68.92%, an Fe2O3 grade of 3.4%, and a silicon grade of 36.53%.

[0051] (4) Silicon niobium separation and flotation were carried out on the silicon niobium pre-enriched concentrate: the silicon niobium separation process was as follows: sodium hydroxide was added as a pH adjuster to adjust the pH of the pulp to 8, the pulp was stirred for 3 minutes, 55 g / t of fluorosilicic acid was added as an inhibitor, the pulp was stirred for 3 minutes, 520 g / t of benzohydroxamic acid-lead metal ion complex collector (the mass ratio of benzohydroxamic acid to lead was 1:1) was added, 12 g / t of BK205 was added as a frother, and roughing operation was carried out; in the concentration operation of silicon niobium separation, only inhibitors were added and the amount was gradually reduced by half; in the concentration operation of silicon niobium separation, only collectors were added and the amount was gradually reduced by half; on this basis, one roughing, four concentrations and one scavenging were carried out, and finally a niobium concentrate with a Nb2O5 grade of 27.86% and a recovery rate of 49.06% was obtained.

[0052] Example 4

[0053] Experiments were conducted on the fractional flotation enrichment of niobium-containing minerals at an Australian niobium mine. The main gangue minerals in this niobium mine are quartz, chlorite, magnetite, and hematite, while the main niobium-containing minerals are columbite and pyrochlore. The ore composition is relatively simple, with an Fe2O3 content of approximately 35%, a SiO2 content of approximately 55%, and a Nb2O5 content of approximately 3.60%.

[0054] (1) Grind the raw ore in a ball mill for 4 min until the -200 mesh size reaches 85%, and then add water to adjust the slurry concentration to 30%;

[0055] (2) Use a weak magnet of 2000 Gs to remove strongly magnetic minerals;

[0056] (3) The product after strong magnetic removal is subjected to silicon niobium pre-enrichment flotation: The silicon niobium pre-enrichment process is as follows: hydrochloric acid is added as a pH adjuster to adjust the pH of the pulp to 4.5, stirring and slurrying for 3 minutes, then 500g / t of fluorosilicic acid is added as an inhibitor, stirring and slurrying for 3 minutes, and finally 1500g / t of tallow diamine is added as a collector, slurrying for 3 minutes, and roughing operation is carried out; the coarse concentrate is subjected to three concentration operations to gradually lower the pH to 2.5, and inhibitors are added and the amount is gradually reduced by half; the coarse tailings are subjected to one scavenging operation and only collectors are added and the amount is reduced by half; the silicon niobium pre-enrichment concentrate has an N2O5 grade of 8.22% and a recovery rate of 76.21%, an Fe2O3 grade of 4.1%, and a silicon grade of 65.65%.

[0057] (4) Silicon niobium separation flotation was carried out on the silicon niobium pre-enriched concentrate: the silicon niobium separation process was as follows: sodium hydroxide was added as a pH adjuster to adjust the pH of the pulp to 8, the pulp was stirred for 3 minutes, 50 g / t of fluorosilicic acid was added as an inhibitor, the pulp was stirred for 3 minutes, 500 g / t of benzohydroxamic acid-lead metal ion complex collector (the mass ratio of benzohydroxamic acid to lead was 1:1) was added, 10 g / t of BK205 was added as a frother, and roughing operation was carried out; in the concentration operation of silicon niobium separation, only inhibitors were added and the amount was gradually reduced by half; in the concentration operation of silicon niobium separation, only collectors were added and the amount was gradually reduced by half; on this basis, one roughing, four concentrations and one scavenging were carried out, and finally a niobium concentrate with a Nb2O5 grade of 45.75% and a recovery rate of 61.32% was obtained.

[0058] Example 5

[0059] Taking the same Australian niobium ore as in Example 4 as the research object, a step-by-step flotation enrichment experiment of niobium-containing minerals was carried out.

[0060] (1) Grind the raw ore in a ball mill for 4 min until the -200 mesh size reaches 85%, and then add water to adjust the slurry concentration to 30%;

[0061] (2) Use a weak magnet of 2000 Gs to remove strongly magnetic minerals;

[0062] (3) The product after strong magnetic removal is subjected to silicon niobium pre-enrichment flotation: The silicon niobium pre-enrichment process is to add hydrochloric acid as a pH adjuster to adjust the pH of the pulp to 4.5, stir and mix for 3 minutes, then add 500g / t of fluorosilicic acid as an inhibitor, stir and mix for 3 minutes, take into account the difference in properties between dodecyl acetic acid amine and tallow diamine, after preliminary test optimization, add 1300g / t of dodecyl acetic acid amine as a collector, mix for 3 minutes, and carry out roughing operation; the coarse concentrate is subjected to three concentration operations to gradually lower the pH to 2.5, and inhibitors are added and the dosage is gradually reduced by half; the coarse tailings are subjected to one scavenging operation and only collectors are added and the dosage is reduced by half; the silicon niobium pre-enriched concentrate has an Nb2O5 grade of 7.56% and a recovery rate of 70.35%, an Fe2O3 grade of 4.5%, and a silicon grade of 68.21%.

[0063] (4) Silicon niobium separation flotation was carried out on the silicon niobium pre-enriched concentrate: the silicon niobium separation process was as follows: sodium hydroxide was added as a pH adjuster to adjust the pH of the pulp to 8, the pulp was stirred for 3 minutes, 50 g / t of fluorosilicic acid was added as an inhibitor, the pulp was stirred for 3 minutes, 550 g / t of benzohydroxamic acid-lead metal ion complex collector (the mass ratio of benzohydroxamic acid to lead was 1:1) was added, 12 g / t of BK205 was added as a frother, and roughing operation was carried out; in the concentration operation of silicon niobium separation, only inhibitors were added and the amount was gradually reduced by half; in the concentration operation of silicon niobium separation, only collectors were added and the amount was gradually reduced by half; on this basis, one roughing, four concentrations and one scavenging were carried out, and finally a niobium concentrate with a Nb2O5 grade of 43.35% and a recovery rate of 57.28% was obtained.

[0064] Example 6

[0065] Taking the same Australian niobium ore as in Example 4 as the research object, a step-by-step flotation enrichment experiment of niobium-containing minerals was carried out.

[0066] (1) Grind the raw ore in a ball mill for 4 min until the -200 mesh size reaches 85%, and then add water to adjust the slurry concentration to 30%;

[0067] (2) Use a weak magnet of 2000 Gs to remove strongly magnetic minerals;

[0068] (3) The product after strong magnetic removal is subjected to silicon niobium pre-enrichment flotation: The silicon niobium pre-enrichment process is as follows: hydrochloric acid is added as a pH adjuster to adjust the pH of the pulp to 4.5, stirring and slurrying for 3 minutes, then 500g / t of fluorosilicic acid is added as an inhibitor, stirring and slurrying for 3 minutes, 1400g / t of carbon atom number dodecyl diamine is added as a collector, slurrying for 3 minutes, and roughing operation is carried out; the coarse concentrate is subjected to three concentration operations to gradually lower the pH to 2.5, and inhibitors are added and the amount is gradually reduced by half; the coarse tailings are subjected to one scavenging operation and only collectors are added and the amount is reduced by half; the silicon niobium pre-enrichment concentrate obtained has an Nb2O5 grade of 7.98% and a recovery rate of 73.66%, an Fe2O3 grade of 4.3%, and a silicon grade of 66.85%.

[0069] (4) Silicon niobium separation flotation was carried out on the silicon niobium pre-enriched concentrate: the silicon niobium separation process was as follows: sodium hydroxide was added as a pH adjuster to adjust the pH of the pulp to 8, the pulp was stirred for 3 minutes, 50 g / t of fluorosilicic acid was added as an inhibitor, the pulp was stirred for 3 minutes, 520 g / t of benzohydroxamic acid-lead metal ion complex collector (the mass ratio of benzohydroxamic acid to lead was 1:1) was added, 12 g / t of BK205 was added as a frother, and roughing operation was carried out; in the concentration operation of silicon niobium separation, only inhibitors were added and the amount was gradually reduced by half; in the concentration operation of silicon niobium separation, only collectors were added and the amount was gradually reduced by half; on this basis, one roughing, four concentrations and one scavenging were carried out, and finally a niobium concentrate with a Nb2O5 grade of 44.68% and a recovery rate of 59.15% was obtained.

Claims

1. A flotation method for niobium-containing minerals, characterized by: The following steps are involved: 1) Crushing, grinding and slurrying the niobium-containing ore to obtain slurry; The main minerals of the niobium-containing ore are siliceous minerals, iron minerals and niobium minerals; the siliceous minerals include at least one of quartz, mica, feldspar, kaolin and chlorite; the iron minerals include at least one of magnetite, hematite, titanomagnetite, ilmenite, hematite, limonite, siderite and ankerite; the niobium minerals include at least one of pyrochlore, columbite, calcite and ferrocodite rutile; The grinding is to meet the -200 mesh particle size ratio of more than 80%; The slurry adjustment is to ensure that the slurry mass concentration reaches 30% to 40%; 2) subjecting the slurry to weak magnetic treatment to remove strongly magnetic minerals to obtain magnetically separated tailings; The magnetic field strength used in the weak magnetic treatment is 1000~2000 Gs; 3) adjusting the pH of the magnetic separation tailings to 2.5-4, adding flotation reagents including iron mineral inhibitors and amine collectors to carry out silicon-niobium mixed flotation to obtain a silicon-niobium mixed concentrate; 4) After adjusting the pH of the silicon-niobium mixed concentrate to 6-8, a flotation agent including a hydroxamic acid metal organic complex collector and a siliceous mineral inhibitor is added to separate silicon and niobium by flotation to obtain a niobium concentrate; The silicon-niobium separation flotation includes 1 roughing stage, 3 to 6 cleaning stages and 1 to 2 scavenging stages; The reagent system for roughing in the silicon-niobium separation flotation is: 30-100 g / t of siliceous mineral depressant, 300-800 g / t of hydroxamic acid metal organic complex collector; 5-30 g / t of foaming agent; The reagent system for the separation and flotation of silicon and niobium is as follows: only siliceous mineral depressants are used, and the reagent is reduced by half in sequence; The reagent system for scavenging in the silicon-niobium separation flotation is: only using a hydroxamic acid metal organic complex collector, and following the principle of reducing the reagent by half in sequence; The hydroxamic acid metal organic complex collector is composed of at least one of benzohydroxamic acid, salicylic hydroxamic acid, and an alkyl hydroxamic acid with 5 to 9 carbon atoms and Pb 2+ 、Zn 2+ 、Al 3+ 、Cu 2+ 、Fe 2+ 、Fe 3+ At least one of them is assembled in a mass ratio of 0.5:1 to 1:3; The siliceous mineral inhibitor includes at least one of fluorosilicic acid, sodium hexametaphosphate, carboxymethyl cellulose, oxalic acid, water glass, salinized water glass, and sodium fluorosilicate; The foaming agent includes BK205.

2. The flotation method of niobium-containing minerals according to claim 1, characterized in that: The silicon-niobium mixed flotation includes 1 roughing stage, 1 to 3 cleaning stages and 1 to 2 scavenging stages.

3. The flotation method of niobium-containing minerals according to claim 2, characterized in that: The reagent system for roughing in the silicon-niobium mixed flotation is: 300-800 g / t of iron mineral depressant and 1000-2000 g / t of amine collector; The reagent system for the flotation of silicon-niobium mixture is: only iron mineral depressants are used, and the principle of reducing the reagent by half is followed; The reagent system for scavenging in the silicon-niobium mixed flotation is: only amine collectors are used, and the principle of reducing the reagents by half is followed.

4. The flotation method of niobium-containing minerals according to claim 3, characterized in that: The amine collector includes at least one of tallow diamine, dodecyl acetamide, and a fatty diamine with 10 to 20 carbon atoms; The iron mineral inhibitor includes at least one of fluorosilicic acid, sodium fluorosilicate, oxalic acid, and sodium humate.

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