A step-by-step enrichment and flotation method for niobium ore

Abstract

The present invention discloses a step-by-step enrichment and flotation method for niobium ore, which belongs to the field of mineral processing technology. After the niobium ore is crushed, ground and slurried, it is subjected to weak magnetic treatment to remove strongly magnetic minerals. After the pH of the magnetic tailings is adjusted, a siliceous mineral inhibitor, a frother and a hydroxamic acid metal organic complex collector are added to carry out iron-niobium mixed flotation. The obtained iron-niobium pre-enriched concentrate is subjected to drug removal treatment, and then an amine collector and an iron mineral inhibitor are used to carry out iron-niobium separation flotation to obtain a niobium concentrate. This method combines the advantages of the collection characteristics of hydroxamic acid metal organic complex collectors and amine collectors for siliceous minerals, iron minerals and niobium minerals, and realizes efficient separation of silicon, iron and niobium by first flotation desiliconization and then flotation deferrification, thereby simplifying the conventional desiliconization and deferrification process, reducing the loss rate of niobium ore, and effectively realizing the resource utilization of niobium ore.

Description

Technical Field

[0001] The present invention relates to a niobium ore beneficiation method, in particular to a step-by-step enrichment and flotation method of niobium ore, belonging to the technical field of ore beneficiation. Background Art

[0002] Niobium is a grayish-white metal with extremely high melting and boiling points. It exhibits corrosion resistance, friction resistance, and excellent ductility. Adding an appropriate amount of niobium to metal materials significantly improves their ductility, electrical conductivity, and heat resistance. These properties make niobium a core material for advanced technologies in aerospace, nuclear energy, medicine, and superconductivity.

[0003] Currently, the main types of niobium deposits being developed are those associated with granite and those associated with alkaline and basic-ultramafic complexes. The primary gangue minerals in these two types of deposits are siliceous gangue minerals (quartz, mica, chlorite, feldspar, kaolin, etc.) and ferrous gangue minerals (magnetite, hematite, ilmenite, limonite, etc.). Currently, flotation is one of the primary methods for industrially recovering niobium resources. Hydroxamic acid collectors are the primary agents used in niobium flotation, demonstrating excellent capture and selectivity for niobium ores. However, these collectors are sensitive to ferrous components, and their sole use can result in large, uncontrollable amounts of iron impurities in niobium concentrates, impacting niobium flotation performance. Currently, ferroniobium concentrates are primarily recovered through co-flotation of iron and niobium. Chinese patent application CN118268138A discloses a method for co-enrichment of iron and niobium resources in rare earth tailings. The method comprises flotation desulfurization of the rare earth tailings, adjusting the pH of the slurry to alkaline, using a metal organic complex (formed by coordination between a divalent or higher metal ion and a hydroxamic acid organic ligand) as a co-flotation collector for iron and niobium minerals, and simultaneously using a gangue mineral inhibitor for flotation separation to obtain a concentrate that is an iron-niobium mixed concentrate.

[0004] Currently, niobium recovery from iron-niobium mixed concentrates is primarily achieved through alkali decomposition, acid decomposition, and chlorination roasting. Each of these technologies has its own advantages and disadvantages. The alkali decomposition method primarily includes alkali melt decomposition and alkaline hydrothermal decomposition. The alkali melt decomposition method, the earliest method adopted in the hydrometallurgical industry for niobium resources, suffers from low niobium yields (<80%), high alkali consumption, and a complex process. The alkaline hydrothermal method significantly lowers the reaction temperature when treating niobium ore compared to the alkali melt decomposition method, significantly reducing alkali consumption to approximately one-sixth of that of the alkali fusion method. However, the process requires pressure and is difficult to operate, hindering its industrialization. Acid decomposition methods primarily include low-temperature sulfuric acid roasting and hydrofluoric acid decomposition. Low-temperature sulfuric acid roasting offers a high metal decomposition rate and can recover most of the valuable metal components in niobium ore. However, it can only be used for easily decomposable niobium ores, has a narrow raw material application range, produces low product purity, and requires a long process flow. The high sulfuric acid consumption during the process makes it rarely used in actual production. The main advantages of the hydrofluoric acid decomposition method are low energy consumption, a simple process, and a decomposition rate of 98% to 99% for high-niobium concentrates. However, its main disadvantages are a low decomposition rate for low-grade niobium concentrates, large amounts of waste slag generated, and high hydrofluoric acid consumption during the process. Furthermore, due to the high toxicity and strong corrosiveness of hydrofluoric acid, this method places high demands on equipment materials, requiring good ventilation and recovery systems, and high production costs. Chlorination roasting is a relatively common and industrially valuable method for extracting niobium. It can be used to process complex niobium concentrates, but existing technologies still have certain drawbacks. For example, traditional solid chlorinating agents have poor chlorine supply performance, resulting in low metal resource recovery rates; and enhanced chlorine supply measures are prone to secondary pollution during implementation. Summary of the Invention

[0005] In response to the technical difficulties in the prior art of niobium ore recovery, such as long process flow, complex procedures, and high niobium ore loss rate, the present invention aims to provide a step-by-step enrichment and flotation method for niobium ore. This method first utilizes the weak capture of gangue minerals, mainly siliceous minerals, and strong capture of ferro-niobium minerals by a hydroxamic acid metal organic complex collector to achieve pre-enrichment of ferro-niobium minerals. Then, the flotation separation of ferro-niobium minerals and niobium minerals by an amine collector, which utilizes the weak capture of gangue minerals, mainly ferrous minerals, and strong capture of niobium minerals, is achieved by utilizing the amine collector to achieve flotation separation of ferrous minerals and niobium minerals, thereby obtaining high-grade niobium minerals. This method fully combines the capture advantages of the hydroxamic acid metal organic complex collector and the amine collector for silicon-containing minerals, iron-containing minerals, and niobium-containing minerals, simplifies the niobium, iron, and silicon separation process, reduces the loss of a large amount of niobium, and effectively improves the flotation recovery rate of the niobium ore. Compared with existing wet and pyrometallurgical processes for niobium-iron separation, this method has the advantages of reduced energy consumption, reduced acid and alkali consumption, and cost savings.

[0006] In order to achieve the above technical objectives, the present invention provides a step-by-step enrichment and flotation method for niobium ore, which comprises the following steps:

[0007] 1) Crushing, grinding and slurrying the niobium ore to obtain slurry;

[0008] 2) subjecting the slurry to weak magnetic treatment to remove strongly magnetic minerals to obtain magnetically separated tailings;

[0009] 3) After the pH of the magnetic separation tailings is adjusted, a siliceous mineral inhibitor, a frother and a hydroxamic acid metal organic complex collector are added to carry out iron-niobium mixed flotation to obtain an iron-niobium pre-enriched concentrate;

[0010] 4) removing the drug from the iron-niobium pre-enriched concentrate to obtain an iron-niobium concentrate;

[0011] 5) Separating and flotating the iron-niobium concentrate using an amine collector and an iron mineral depressant to obtain a niobium concentrate and iron tailings.

[0012] The step-by-step enrichment flotation method for niobium ore provided by the present invention is mainly aimed at siliceous minerals, ferrous minerals and niobium minerals in niobium ore. 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. When a single hydroxamic acid collector is used, although it exhibits excellent capture and selectivity for niobium minerals, it is relatively sensitive to ferrous minerals. Usually, ferrous minerals and niobium minerals are enriched in the form of a mixed concentrate, and subsequent separation of ferrous minerals and niobium minerals is difficult. When a single amine collector is used, although it exhibits good capture for niobium minerals and weak capture ability for ferrous minerals, it 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 ore and the defects of amine collectors and hydroxamic acid collectors in the flotation separation process between siliceous minerals, iron minerals and niobium minerals, and designs a reasonable niobium ore step-by-step flotation and enrichment flotation method. The method first performs weak magnetic separation on niobium ore to remove strongly magnetic gangue minerals including magnetite, and non-magnetic minerals are preferentially pre-enriched using hydroxamic acid metal organic complex collectors. By utilizing the characteristics of hydroxamic acid metal organic complex collectors that have strong capture properties for niobium minerals and iron minerals but are insensitive to siliceous minerals, siliceous minerals can be preferentially removed, while iron minerals and niobium minerals are obtained. After pre-enrichment, the niobium-iron mixed concentrate is separated using an amine collector. The amine collector's weak capture of iron minerals and strong capture of niobium minerals are used to remove iron minerals and achieve further enrichment of the niobium ore. In summary, the process of the present invention combines the advantages of the capture characteristics of hydroxamic acid metal organic complex collectors and amine collectors 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 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; 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 ferrocolumbite rutile.

[0014] As a preferred solution, the grinding process is performed to achieve a mass fraction of at least 80% of the -200 mesh size. Grinding to an appropriate particle size allows for the complete dissociation of the niobium minerals, facilitating subsequent flotation separation.

[0015] As a preferred solution, the slurry adjustment is to meet the slurry mass concentration of 30% to 40%.

[0016] As a preferred solution, the weak magnetic treatment uses a magnetic field strength of 1000-2000 Gs. This weak magnetic treatment can preferentially remove magnetite, ilmenite, and hematite, which have a high proportion and strong magnetism, thereby reducing the difficulty of subsequent iron-niobium flotation separation.

[0017] As a preferred solution, the pH is adjusted to 8.5-10. Alkaline compounds such as Na2CO3 and NaOH are used to adjust the pH. The optimal flotation pH range for the hydroxamic acid metal organic complex collector is 8.5-10. Within the preferred pH range, divalent or higher-valent metal ions and their hydroxide-complexed metal ions assemble with the hydroxamic acid ligand to form a hydroxamic acid metal organic complex, which not only has colloidal properties but also carries a positive charge in its colloidal structure. It can be adsorbed on the mineral surface through electrostatic action, changing the surface potential of the mineral from negative to positive, thereby enhancing the adsorption and binding ability of the collector on the mineral surface.

[0018] As a preferred embodiment, the iron-niobium mixed flotation process includes one roughing stage, one to two cleaning stages, and one to two scavenging stages. As a more preferred embodiment, the roughing agent system includes: 300-800 g / t of siliceous mineral depressant, 1000-2000 g / t of hydroxamic acid metal organic complex collector, and 20-100 g / t of frother. As a more preferred embodiment, the roughing agent system includes: using only siliceous mineral depressant, with the agent dosage gradually reduced by half. As a more preferred embodiment, the scavenging agent system includes: using only hydroxamic acid metal organic complex collector, with the agent dosage gradually reduced by half. Under the preferred flotation conditions, silicon can be efficiently removed from niobium minerals, while iron and niobium minerals are efficiently enriched to obtain ferroniobium concentrate.

[0019] 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 above is assembled in a mass ratio of 0.5:1 to 1:3. The divalent or higher metal ions are derived from water-soluble metal salt chemical reagents such as lead nitrate, lead chloride, aluminum chloride, and copper chloride. The template effect of the high-valent metal ions is utilized to regulate the assembly of hydroxamic acid ligands, pre-assembling a hydroxamic acid metal organic complex 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 and iron minerals, facilitating the co-flotation of iron and niobium. In addition, the capture ability of hydroxamic acid metal organic complexes generated at different molar ratios of high-valent metal ions to hydroxamic acid ligands for minerals varies. Under the optimal ratio, the capture ability of hydroxamic acid metal organic complexes for niobium-containing minerals and iron minerals is stronger and the selectivity is better.

[0020] As a preferred embodiment, the siliceous mineral inhibitor includes at least one of sodium hexametaphosphate, carboxymethyl cellulose, tannin, water glass, salted water glass, sodium fluorosilicate, fluorosilicic acid, and starch. Hydroxamic acid metal organic complexes, which have high selectivity for niobium and iron minerals and strong capture capacity, when used in conjunction with a suitable siliceous mineral inhibitor, can improve the removal efficiency of siliceous minerals.

[0021] As a more preferred solution, the foaming agent includes BK205.

[0022] As a preferred solution, the drug removal treatment conditions include adjusting the pH to 11-12, stirring at 1000-3000 rpm, and maintaining the mixture for 10-30 minutes. Strong alkalinity and high-speed stirring promote the removal of the hydroxamic acid metal organic complex from the mineral surface, facilitating the subsequent action of amine collectors and iron mineral inhibitors on the niobium and iron mineral surfaces. A strong base such as sodium hydroxide is used to adjust the pH.

[0023] As a preferred embodiment, the iron-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 stage uses a reagent system consisting of 300-800 g / t of iron mineral depressant and 1000-2000 g / t of amine collector. As a more preferred embodiment, the roughing stage uses only iron mineral depressant, with the reagent level gradually reduced by half. As a more preferred embodiment, the scavenging stage uses only amine collector, with the reagent level gradually reduced by half. Under these preferred flotation conditions, niobium minerals can be separated from iron minerals by flotation.

[0024] As a preferred embodiment, the amine collector includes at least one of tallow diamine, dodecyl acetic acid amine, and a fatty diamine having 10 to 20 carbon atoms. Preferred amine collectors have a strong effect on niobium minerals but a weak effect on ferrous minerals. Under the premise of flotation desiliconization, amine collectors can achieve efficient separation of ferrous and niobium minerals. A further preferred amine collector is tallow diamine.

[0025] As a preferred embodiment, the iron mineral inhibitor includes at least one of fluorosilicic acid, sodium fluorosilicate, oxalic acid, sodium humate, dextrin, starch, and carboxymethyl cellulose. The preferred iron mineral inhibitor can selectively act on the ferric and ferrous ions on the surface of the iron mineral, thereby achieving surface hydrophilic modification and thereby inhibiting the flotation of the iron mineral.

[0026] Compared with the existing technology, the technical solution of the present invention brings the following beneficial technical effects:

[0027] (1) The present invention makes full use of the selectivity and collecting properties of hydroxamic acid metal organic complex collector for iron minerals and niobium minerals, and uses a siliceous mineral inhibitor in combination to achieve the inhibition of gangue minerals mainly composed of siliceous minerals, achieves efficient desiliconization, and eliminates the influence of siliceous minerals on the subsequent flotation separation process of iron minerals and niobium minerals using amine collectors.

[0028] (2) The present invention makes full use of the collection characteristics of amine collectors for niobium minerals, and uses iron mineral inhibitors and a pre-drug removal process in combination to solve the technical problem that it is difficult to further separate iron minerals from niobium minerals in iron-niobium mixed concentrates, thereby achieving effective flotation enrichment of niobium ore.

[0029] (3) The present invention adopts flotation method to replace the complex desliming and desiliconization operations at the front end of the traditional niobium flotation process, eliminating the large amount of niobium loss caused by the multi-stage grinding-desliming-desiliconization operations, while simplifying the niobium ore selection process and improving the niobium ore recovery rate.

[0030] (4) The present invention adopts the flotation method to achieve efficient separation of iron and niobium, which greatly reduces the technical problems of high energy consumption, large reagent consumption and high cost in achieving niobium and iron separation by wet or fire methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a flow chart of the step-by-step enrichment and flotation process of niobium ore provided by the present invention. DETAILED DESCRIPTION

[0032] The following specific examples are intended to further illustrate the present invention, but are not intended to limit the scope of protection of the claims of the present invention.

[0033] Example 1

[0034] A niobium ore fractional flotation enrichment experiment was conducted using niobium-bearing phosphate tailings from a Brazilian mine. The main components of this phosphate tailings are quartz, magnesia serpentine, mica, magnetite-maghemite, hematite, limonite, ilmenite, pyrochlore, and barium-strontium pyrochlore. Siliceous minerals, primarily quartz, magnesia serpentine, and mica, account for approximately 50%; iron minerals, including magnetite-maghemite, account for approximately 14%, and limonite, hematite, and ilmenite, account for approximately 21%; niobium minerals, primarily pyrochlore and barium-strontium pyrochlore, account for approximately 0.58%; and the N2O5 content of the niobium-bearing phosphate tailings is approximately 0.59%.

[0035] (1) The proportion of -200 mesh of niobium-containing phosphate tailings is about 55%. The ball mill is used to grind the ore for 2 minutes until the proportion of -200 mesh of the original ore reaches 80%. Most of the niobium minerals are fully dissociated into monomers. Then water is added to adjust the slurry to a mass concentration of 33%.

[0036] (2) A weak magnet of 2000 Gs is used to remove strongly magnetic minerals to obtain magnetic products and non-magnetic products.

[0037] (3) The non-magnetic product continued to undergo the iron-niobium pre-enrichment experiment: in the iron-niobium pre-enrichment roughing operation, sodium hydroxide was used as the pH adjuster to adjust the slurry pH to 9.5, 500 g / (t·original ore) of sodium fluorosilicate was used as the inhibitor, 1500 g / (t·original ore) of benzohydroxamic acid-lead metal ion complex collector (the mass ratio of benzohydroxamic acid to lead was 1:1), and 50 g / (t·original ore) of BK205 was used as the foaming agent; in the iron-niobium pre-enrichment and concentration operation, only the inhibitor was added and the dosage was reduced by half; in the iron-niobium pre-enrichment and scavenging operation, only the collector and foaming agent were added and the dosage was reduced by half; on this basis, one roughing, two concentrations and one scavenging were carried out to obtain the iron-niobium pre-enrichment concentrate.

[0038] (4) De-doping experiment of iron-niobium pre-enriched concentrate: The pH of the ore pulp of the iron-niobium pre-enriched concentrate was adjusted to 11.5 using sodium hydroxide as a pH adjuster, and the pulping speed was set to 2000 r / min, the pulping time was set to 20 min, and a roughing de-doping flotation operation was carried out to obtain a foam product and the iron-niobium pre-enriched concentrate after de-doping.

[0039] (5) After the removal of the drug, the iron-niobium pre-enriched concentrate was used for the iron-niobium separation operation: 500 g / (t·ore) of fluorosilicic acid and 250 g / (t·ore) of corn dextrin were used as inhibitors, and 1000 g / (t·ore) of tallow diamine was used as collector for the roughing operation of the iron-niobium separation; in the concentrating operation of the iron-niobium separation, only inhibitors were added and the dosage was reduced by half; in the iron-niobium pre-enrichment scavenging operation, only collectors were added and the dosage was reduced by half; on this basis, one roughing operation, four concentrating operations and one scavenging operation were carried out, and finally a niobium concentrate with an N2O5 grade of 25.39% and a recovery rate of 53.49% was obtained.

[0040] Example 2

[0041] A niobium ore deposit in Australia was used as the research object for a step-by-step flotation enrichment experiment. The main gangue minerals in this niobium ore are quartz, chlorite, magnetite, hematite, and columbite. Quartz accounts for approximately 60%, and the N2O5 content is approximately 3.80%.

[0042] (1) The raw ore is crushed and ground to -200 mesh with a proportion of 80%, and most of the niobium minerals are fully dissociated into monomers. Then water is added to adjust the slurry to a slurry mass concentration of 33%.

[0043] (2) A weak magnet of 2000 Gs is used to remove strongly magnetic minerals to obtain magnetic products and non-magnetic products.

[0044] (3) The non-magnetic product continued to undergo the iron-niobium pre-enrichment experiment: in the iron-niobium pre-enrichment roughing operation, sodium hydroxide was used as the pH adjuster to adjust the slurry pH to 9.5, 200 g / (t·original ore) of fluorosilicic acid was used as the inhibitor, 2000 g / (t·original ore) of benzohydroxamic acid-lead metal ion complex collector (the mass ratio of benzohydroxamic acid to lead was 1:1), and 50 g / (t·original ore) of BK205 was used as the foaming agent; in the iron-niobium pre-enrichment and concentration operation, only the inhibitor was added and the dosage was reduced by half; in the iron-niobium pre-enrichment and scavenging operation, only the collector and foaming agent were added and the dosage was reduced by half; on this basis, one roughing, two concentrating and one scavenging were carried out to obtain the iron-niobium pre-enrichment concentrate;

[0045] (4) De-doping experiment of iron-niobium pre-enriched concentrate: The pH of the ore pulp of the iron-niobium pre-enriched concentrate was adjusted to 11.5 using sodium hydroxide as a pH adjuster, and the pulping speed was set to 2000 r / min, the pulping time was set to 20 min, and a roughing de-doping flotation operation was carried out to obtain a foam product and the iron-niobium pre-enriched concentrate after de-doping.

[0046] (5) After the removal of the drug, the iron-niobium pre-enriched concentrate was used for the iron-niobium separation operation: 100 g / (t·original ore) of fluorosilicic acid was used as an inhibitor and 1000 g / (t·original ore) of tallow diamine was used as a collector for the roughing operation of the iron-niobium separation; in the concentrating operation of the iron-niobium separation, only the inhibitor was added and the dosage was reduced by half; in the iron-niobium pre-enrichment scavenging operation, only the collector was added and the dosage was reduced by half; on this basis, one roughing operation, three concentrating operations and one scavenging operation were carried out, and finally a niobium concentrate with an N2O5 grade of 43.80% and a recovery rate of 67.63% was obtained.

[0047] Example 3

[0048] Taking the original ore in Example 1 as the research object, the effects of different amine collectors on the enrichment of niobium ore were compared.

[0049] (1) The proportion of -200 mesh of niobium-containing phosphate tailings is about 55%. The ball mill is used to grind the ore for 2 minutes until the proportion of -200 mesh of the original ore reaches 80%. Most of the niobium minerals are fully dissociated into monomers. Then water is added to adjust the slurry to a mass concentration of 33%.

[0050] (2) A weak magnet of 2000 Gs is used to remove strongly magnetic minerals to obtain magnetic products and non-magnetic products.

[0051] (3) The non-magnetic product continued to undergo the iron-niobium pre-enrichment experiment: in the iron-niobium pre-enrichment roughing operation, sodium hydroxide was used as the pH adjuster to adjust the slurry pH to 9.5, 500 g / (t·original ore) of sodium fluorosilicate was used as the inhibitor, 1500 g / (t·original ore) of benzohydroxamic acid-lead metal ion complex collector (the mass ratio of benzohydroxamic acid to lead was 1:1), and 50 g / (t·original ore) of BK205 was used as the foaming agent; in the iron-niobium pre-enrichment and concentration operation, only the inhibitor was added and the dosage was reduced by half; in the iron-niobium pre-enrichment and scavenging operation, only the collector and foaming agent were added and the dosage was reduced by half; on this basis, one roughing, two concentrations and one scavenging were carried out to obtain the iron-niobium pre-enrichment concentrate.

[0052] (4) De-doping experiment of iron-niobium pre-enriched concentrate: The pH of the ore pulp of the iron-niobium pre-enriched concentrate was adjusted to 11.5 using sodium hydroxide as a pH adjuster, and the pulping speed was set to 2000 r / min, the pulping time was set to 20 min, and a roughing de-doping flotation operation was carried out to obtain a foam product and the iron-niobium pre-enriched concentrate after de-doping.

[0053] (5) A comparative test of amine collector flotation was carried out on the iron-niobium pre-enriched concentrate after dedoping: 500 g / (t·ore) of fluorosilicic acid and 250 g / (t·ore) of corn dextrin were used as inhibitors, and 1000 g / (t·ore) of tallow diamine, dodecyl acetic acid amine, lauryl diamine, dodecylamine, and dodecyl tertiary amine were used as collectors for the roughing operation of iron-niobium separation; only inhibitors were added in the fine operation of iron-niobium separation and the principle of reducing the dosage by half was followed; only collectors were added in the iron-niobium pre-enrichment scavenging operation and the principle of reducing the dosage by half was followed; on this basis, one roughing operation and four fine operations were carried out to finally obtain the final niobium concentrate.

[0054] As can be seen from Table 1, when tallow diamine is used as a collector for separating niobium and iron in niobium-iron mixed concentrate, its niobium recovery rate and the grade of the obtained niobium concentrate are much higher than those of other amine collectors.

[0055]

Claims

1. A step-by-step enrichment and flotation method for niobium ore, characterized by: The following steps are involved: 1) Crushing, grinding and slurrying the niobium ore to obtain slurry; 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; 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 ferroniobium rutile; The grinding process is such that the mass fraction of the -200 mesh particle size reaches 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 1000~2000Gs; 3) After the pH of the magnetic separation tailings is adjusted, a siliceous mineral inhibitor, a frother and a hydroxamic acid metal organic complex collector are added to carry out iron-niobium mixed flotation to obtain an iron-niobium pre-enriched concentrate; Iron-niobium mixed flotation includes 1 roughing stage, 1-2 cleaning stages and 1-2 scavenging stages; The reagent system for roughing in the iron-niobium mixed flotation is: 300-800 g / t of siliceous mineral depressant, 1000-2000 g / t of hydroxamic acid metal organic complex collector, and 20-100 g / t of frother. The reagent system for roughing in the iron-niobium mixed flotation is: only siliceous mineral depressants are used, and the principle of reducing the reagent by half is followed; The reagent system for scavenging in the iron-niobium mixed 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 sodium hexametaphosphate, carboxymethyl cellulose, tannin, water glass, salinized water glass, sodium fluorosilicate, fluorosilicic acid, and starch; The foaming agent includes BK205; 4) performing drug removal treatment on the iron-niobium pre-enriched concentrate to obtain an iron-niobium concentrate; 5) Separating and flotating the iron-niobium concentrate using an amine collector and an iron mineral depressant to obtain a niobium concentrate and iron tailings.

2. The step-by-step enrichment and flotation method of niobium ore according to claim 1, characterized in that: The pH is adjusted to be between 8.5 and 10.

3. The step-by-step enrichment and flotation method for niobium ore according to claim 1, characterized in that: The conditions for the drug removal treatment are: adjusting the pH to 11-12, stirring at a speed of 1000-3000 r / min, and the time being 10-30 min.

4. The step-by-step enrichment and flotation method of niobium ore according to claim 1, characterized in that: The iron-niobium separation flotation includes 1 roughing stage, 3 to 6 cleaning stages and 1 to 2 scavenging stages.

5. The step-by-step enrichment and flotation method of niobium ore according to claim 4, characterized in that: The reagent system for roughing in the iron-niobium separation flotation is: 300-800 g / t of iron mineral depressant and 1000-2000 g / t of amine collector; The reagent system for roughing in the iron-niobium separation flotation is: only iron mineral depressants are used, and the reagent is reduced by half in sequence; The reagent system for scavenging in the iron-niobium separation flotation is: only amine collectors are used, and the principle of reducing the reagent by half is followed; 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, sodium humate, dextrin, starch, and carboxymethyl cellulose.

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