Ore dressing method for recovering pyrochlore from high-silicon and high-calcium carbonate-type niobium ore

Abstract

The present invention discloses a beneficiation method for recovering pyrochlore from high-silicon, high-calcium carbonate-type niobium ore. The method comprises the following steps: slurrying the ground ore product, subjecting it to a coarse-fine, weak magnetic separation to obtain a magnetite concentrate and a weak magnetic tailing; subjecting the weak magnetic tailing to niobium flotation in a coarse-fine, two-sweep, and three-sweep process to obtain a flotation niobium concentrate and a flotation niobium tailing 1; subjecting the flotation niobium concentrate to a coarse-fine, three-sweep, and two-sweep process to obtain a niobium concentrate 1 and a strong magnetic concentrate; and subjecting the strong magnetic concentrate to a coarse-fine, four-sweep, and one-sweep process to obtain a niobium concentrate 2 and a flotation niobium tailing 2. By utilizing the characteristics of different types of niobium flotation reagents and rationally optimizing the process flow, the method simplifies the desilicate, decarbonate (dephosphorization and calcium), and desludging processes in the traditional niobium flotation process. This significantly shortens the niobium flotation process, reduces niobium losses before flotation, and fundamentally eliminates the problem of low niobium recovery, significantly improving niobium recovery. Ultimately, a niobium concentrate with a niobium grade exceeding 50% and a high recovery rate is obtained.

Description

Technical Field

[0001] The present invention relates to the field of mineral beneficiation and processing technology, and in particular to a beneficiation method for recovering pyrochlore from high-silicon and high-calcium carbonate-type niobium ore. Background Art

[0002] Niobium is an important rare metal. Adding niobium to other metals can make various high-temperature resistant and high-strength materials. Adding an appropriate amount of niobium to different metals can significantly improve the metal's ductility, corrosion resistance, heat resistance, strength, conductivity and other properties.

[0003] Niobium minerals primarily occur in granite pegmatite and carbonate deposits. While there are numerous types of niobium minerals, only about 10 are used as industrial raw materials, including the columbite-tantalite series, ferrocolumbite, calcite, niobium calcite, ferrocolumbite rutile, and pyrochlore. Granite pegmatite is primarily composed of tantalum and niobium, but the niobium grade is relatively low. Carbonate-type pyrochlore, with its higher niobium grade, is the primary source of niobium metal. Pyrochlore accounts for 95% of the global niobium supply, so the development and utilization of carbonate-type pyrochlore plays a crucial role in increasing the global niobium supply.

[0004] The Alaksa mine is a weathered laterite carbonate-type pyrochlore ore. The ore contains only minor carbonate and silicate minerals, primarily fine mud and magnetite. The primary method for recovering pyrochlore from this ore is as follows: The ore is ground and then magnetically separated. Non-magnetic minerals undergo desliming. A three-stage cyclone system is used to remove fine mud smaller than 5μm. The desliming process yields approximately 12% mud, with niobium losses of 5% to 7%. Niobium flotation is activated using sodium fluorosilicate or fluorosilicic acid, and the pH is adjusted to 2.5 to 3.5 with hydrochloric acid. A cation collector, an amine, is used to obtain a niobium concentrate with a niobium grade of 55% to 60%. This ore contains virtually no acid-consuming carbonate minerals, allowing the pH to be adjusted directly to acidic without removing carbonate minerals. Furthermore, the low silicate content allows the use of an amine collector without desiliconization. However, this process results in a high fine mud yield and significant niobium losses in the fine mud.

[0005] The Niobek ore is an alkaline carbonate pyrochlore, with 60% carbonates and 20% silicates. A grinding system consisting of a rod mill, ball mill, spiral classifier, and vibrating screen is used on-site to reduce fine mud. The ground product undergoes two-stage cyclone desludging, and a fatty acid collector is added to the desludged product for carbonate flotation. The flotation tailings undergo weak magnetic iron removal. The weak magnetic tailings are desiliconized using an etheramine collector, with sodium hydroxide and starch as inhibitors. The desiliconized tailings are treated with a diamine collector and the pH adjusted to 2.7 with hydrochloric acid. After multiple stages of concentrating, a niobium concentrate containing 45% to 50% niobium is obtained. Hydrochloric acid is used to leach carbonates and phosphates from the niobium concentrate, ultimately yielding a pyrochlore concentrate with a niobium grade of 55% to 60%. This complex process requires the treatment of each gangue mineral prior to niobium flotation, resulting in significant cumulative pyrochlore losses. Furthermore, the high acidity required to dissolve carbonates during pyrochlore flotation consumes significant amounts of acid, increasing production costs.

[0006] The Katalao Mine is a laterite-type pyrochlore, containing a large amount of mica and iron-containing minerals. The rod mill-classification process is used for grinding. The grinding products enter the weak magnetic iron removal operation, and the weak magnetic tailings enter the cyclone for desliming to remove the 10μm fine particles. The deslimed products enter the reverse flotation for desilicate removal, using etheramine as a collector and sodium hydroxide + starch as inhibitors. The obtained flotation tailings are added with fatty acid collectors for decarbonation. The obtained flotation tailings enter the niobium selection operation, using amines as collectors, hydrochloric acid as a regulator, and sodium fluorosilicate as a inhibitor. The pyrochlore is floated under strong acidic conditions. The obtained pyrochlore is then leached with hydrochloric acid to remove phosphates and carbonates, and finally a niobium concentrate with a niobium grade of 63.70% is obtained. The desilicate collector used in this process is highly corrosive. At the same time, the niobium flotation operation uses highly corrosive hydrochloric acid as a regulator. The amount of acid used is large and the equipment is severely corrosive. Hydrochloric acid and fluorosilicic acid have a great impact on the environment and the working environment is poor.

[0007] In summary, due to the large number of associated mineral components, the beneficiation process of pyrochlore is very complex. The flotation process of weathered ore and high-silicon and high-calcium carbonate-type pyrochlore is basically similar, all of which involve desludging, reverse flotation of silicates, reverse flotation of carbonates, magnetic separation, pyrochlore flotation, sulfide flotation, and leaching for phosphorus removal. Amine collectors are sensitive to fine mud, and the presence of muddy particles will reduce the flotation efficiency of pyrochlore. Desludging is required before flotation, and the desludging process results in a large amount of niobium loss. Reverse flotation to remove carbonates is mainly affected by strong acidic separation conditions. When there are a lot of carbonate minerals, a large amount of hydrochloric acid or fluosilicic acid needs to be added to adjust the pH. At the same time, a large number of bubbles are generated during the pH adjustment process, which affects the flotation process. Reverse flotation to remove carbonates is mainly because the silicate minerals in the ore are susceptible to the action of amine collectors and need to be removed to facilitate the subsequent enrichment of pyrochlore and ultimately obtain qualified concentrate.

[0008] The current production process for high-silicon, high-calcium carbonate-type pyrochlore suffers from several significant challenges: 1. The pyrochlore beneficiation process is complex, and niobium mineral loss is inevitable at each stage. This cumulative effect results in significant niobium metal loss before niobium flotation, resulting in a niobium recovery rate of only 50%-60% in the final niobium concentrate. Nearly 30% of the niobium is lost during desludging, decarbonation, desilicate removal, and dehydration. 2. The pH range before and after niobium flotation varies significantly, from strongly alkaline to strongly acidic, creating a poor operating environment, high acid consumption, and severe equipment corrosion. 3. Residual reagents from decarbonation and desilicate removal affect niobium flotation, requiring additional dehydration and dehydration steps after each operation, resulting in some niobium loss. The niobium flotation reagent system is a major contributor to the complexity of the entire process. Optimizing the flotation reagent system is key to streamlining the entire process and improving niobium recovery. Summary of the Invention

[0009] The present invention aims to address the problems of the current beneficiation process for recovering pyrochlore from high-silicon and high-calcium carbonate-type niobium ore, such as a relatively long process flow and a low niobium recovery rate. An improved beneficiation method is provided. The method adopts a process of weak magnetic iron removal - flotation selection of niobium - strong magnetic impurity removal - flotation selection of niobium to treat such carbonate-type niobium ore, forming a reasonable process method formulated based on the properties of the ore and the properties of the reagent. The method greatly simplifies the process flow, improves the operating environment of niobium flotation, and increases the niobium recovery rate, thereby achieving effective recovery of niobium resources.

[0010] The technical solution of the present invention comprises the following steps:

[0011] S1. Weak magnetic separation: The ground ore products are subjected to weak magnetic roughing and weak magnetic concentrating operations to obtain magnetite concentrate and weak magnetic tailings.

[0012] S2. Primary niobium flotation: The weakly magnetic tailings from S1 are subjected to a primary niobium flotation process by adding a pH adjuster to adjust the slurry pH to 7-9. A depressant, activator, and collector are then added for a primary roughing process. The depressant and collector are then added for one to three final cleaning processes. Finally, a collector is added for one to two scavenging processes, yielding a flotation niobium concentrate and selected niobium tailings 1. This step utilizes a highly selective fatty acid chelating collector that resists interference from fine mud and has a weak ability to capture gangue minerals, particularly silicate minerals. The depressant is a weak acid, and the pH during operation is weakly alkaline. Carbonate minerals do not interfere with flotation, making this process suitable for flotation slurries containing high silicon and calcium content.

[0013] S3. Intense Magnetic Separation: The flotation niobium concentrate obtained in S2 is subjected to intense magnetic separation to produce niobium concentrate 1 and intense magnetic concentrate. Introducing this step after the primary flotation concentrate achieves multiple goals, including reducing magnetic separation throughput, improving niobium concentrate quality, and classifying finer particles and magnetic minerals, creating conditions for subsequent secondary niobium recovery.

[0014] S4. Secondary niobium flotation: The strong magnetic concentrate obtained in S3 is treated with a conditioning agent (fluosilicic acid in this step) for secondary niobium flotation. The pH of the ore pulp is adjusted to 5. A collector is then added for a roughing separation. The conditioning agent and collector are then added for one to four cleaning passes. Finally, a collector is added for a scavenging separation, yielding niobium concentrate 2 and selected niobium tailings 2. This step utilizes an amine-based collector, which is sensitive to fine mud and weak at capturing ilmenite. A strong acid is used as an inhibitor. During the strong magnetic separation process, acid-consuming gangue minerals are prevented from entering this process, significantly reducing acid consumption.

[0015] The high-silicon and high-calcium carbonate-type niobium ore described in the present invention refers to a high-silicon and high-calcium carbonate-type niobium ore with carbonate and silicate as main gangue minerals, and the total content of the two exceeds 70%.

[0016] The present invention is based on the properties of the ore. By adjusting the reagent system for niobium flotation operations, utilizing the different characteristics of two types of collectors, and rationally designing the process, the loss of niobium in each operation is fundamentally eliminated. The chelating combination collector has a neutral operating environment and is highly resistant to fine mud. It has basically no collecting effect on silicate minerals. This series of characteristics enables the elimination of processes such as desilicate, decarbonate, and desludging before niobium flotation. However, it also has a certain collecting effect on magnetic minerals containing ilmenite and iron. Subsequently, strong magnetic operations are required to remove magnetic impurity minerals such as ilmenite from the flotation niobium concentrate to further improve the niobium grade. After strong magnetic separation, there is still some niobium in the strong magnetic concentrate. The strong magnetic concentrate is mainly composed of magnetic minerals containing ilmenite and iron. After strong magnetic separation, the content of carbonate, silicate minerals and fine mud in the strong magnetic concentrate is very low, which creates conditions for the amine recovery process and the amount of fluorosilicic acid used can also be greatly reduced. Through the rational optimization of this process flow, the desilicate, decarbonate, desludging, de-drug and dehydration operations required by the amine process were eliminated. At the same time, the quality of the flotation niobium concentrate obtained in the first stage was improved. The niobium in the obtained strong magnetic concentrate was recovered by secondary flotation through the amine process, and finally a niobium concentrate with a niobium grade of more than 50% and a high recovery rate was obtained.

[0017] Preferably, the grinding in step S1 is to grind the raw ore until the -0.1 mm particles account for 72-82% of the total particles. More preferably, the grinding fineness is reduced to below 78%, which can simplify the number of grinding stages, reduce the number of grinding mills, and greatly reduce on-site electricity costs.

[0018] In one preferred embodiment, the magnetic field strength of the weak magnetic roughing process in S1 is 0.1 to 0.3 T, preferably 0.2 T; the magnetic field strength of the weak magnetic concentrating process is 0.08 to 0.2 T, preferably 0.15 T.

[0019] In one preferred embodiment, the amount of the pH adjuster added in S2 is 2500-3000 g / t, and the pH is adjusted to 6.5-8.0, preferably 2700 g / t, preferably 7.0.

[0020] In the primary rough selection of S2, the addition amount of the inhibitor is 20-60 g / t, preferably 45 g / t; the addition amount of the activator is 100-200 g / t, preferably 150 g / t; the addition amount of the collector is 1500-2000 g / t, preferably 1800 g / t.

[0021] In the primary concentration of S2, the amount of inhibitor added is 20-40 g / t, preferably 30 g / t; the amount of collector added is 160-200 g / t, preferably 180 g / t.

[0022] In the secondary concentration of S2, the amount of inhibitor added is 12-20 g / t, preferably 15 g / t; the amount of collector added is 80-120 g / t, preferably 100 g / t.

[0023] In the tertiary concentrating of S2, the amount of inhibitor added is 12-20 g / t, preferably 15 g / t; the amount of collector added is 40-80 g / t, preferably 60 g / t.

[0024] In the first sweep of S2, the amount of collector added is 200-300 g / t, preferably 250 g / t.

[0025] In the secondary scavenging of S2, the amount of collector added is 100-150 g / t, preferably 130 g / t.

[0026] In one preferred embodiment, the magnetic field strength of the strong magnetic roughing separation in S3 is 0.6-1.0T, preferably 0.8T.

[0027] In one preferred embodiment, the amount of fluorosilicic acid added in S4 is 1500-2000 g / t, and the pH is adjusted to 4.5-6.0, preferably 1800 g / t, preferably 5.0.

[0028] In the primary roughing of S4, the amount of collector added is 600-1000 g / t, preferably 800 g / t.

[0029] In the primary concentrating of S4, the amount of fluorosilicic acid added is 200-400 g / t, preferably 300 g / t; the amount of collector added is 160-200 g / t, preferably 180 g / t.

[0030] In the secondary concentration of S4, the amount of fluorosilicic acid added is 200-400 g / t, preferably 300 g / t; the amount of collector added is 80-120 g / t, preferably 100 g / t.

[0031] In the tertiary concentrating of S4, the addition amount of fluorosilicic acid is 100-300 g / t, preferably 200 g / t; the addition amount of collector is 40-80 g / t, preferably 60 g / t.

[0032] In the fourth round of concentrating in S4, the amount of fluorosilicic acid added is 100-300 g / t, preferably 200 g / t; the amount of collector added is 40-80 g / t, preferably 60 g / t.

[0033] In the first sweep of S4, the amount of collector added is 100-200 g / t, preferably 150 g / t.

[0034] The amount of each of the above additives can be appropriately adjusted with reference to the amount commonly used in the industry, and the strength of the weak magnetic field and the strong magnetic field can be adjusted with reference to industry data.

[0035] The collector in step S2 is a new type of chelating combined collector that is highly effective and resistant to fine mud interference; the pH adjuster is a combination of a non-toxic and environmentally friendly organic weak acid and modified water glass; the activator is an inorganic salt containing lead ions; and the inhibitor is one or more of CMC, dextrin, tannic acid or lignin.

[0036] Preferably, the novel chelating combined collector with high efficiency and resistance to fine mud interference is selected from C 7-9 At least one of alkyl isoximic acid, aryl hydroximic acid, benzohydroximic acid or octyl hydroximic acid is prepared with oxidized paraffin soap in a ratio of 10-20:1; the organic weak acid is selected from at least one of oxalic acid, citric acid, quinic acid, salicylic acid and tartaric acid, and the ratio of the organic weak acid to modified water glass is 3-5:1; the activator is lead nitrate and / or lead chloride.

[0037] In step S4, the collector is an amine collector such as dodecylamine acetate, octadecylamine acetate, coconut amine, etc., which has both collecting and foaming properties; fluorosilicic acid is used as an adjusting agent, which can both adjust the pH and inhibit gangue minerals.

[0038] This invention addresses prominent issues in the pyrochlore recovery process of high-silicon, high-calcium carbonate-type niobium ores, such as lengthy processes, severe niobium losses in various operations, and significant impacts from residual reagents. By implementing a rational niobium flotation reagent system, this process eliminates desilicate, decarbonate, and desludging, improves the niobium flotation reagent system, and simplifies the process flow, thereby reducing niobium losses in desilicate and carbonate operations and fine mud. Simultaneously, high-intensity magnetic separation is introduced to improve the grade of the niobium concentrate, allowing niobium minerals to be recovered from the high-intensity magnetic concentrate, resulting in a high-grade, high-recovery niobium concentrate.

[0039] The present invention differs from the prior art in that: (1) the decarbonation and desilicate operations are eliminated, thereby avoiding the loss of niobium in these two operations and eliminating the influence of residual reagents on niobium flotation; (2) the desludging operation is eliminated, thereby avoiding the loss of niobium in this operation; (4) the niobium flotation reagent system is greatly adjusted, and a new type of chelating collector with high efficiency and resistance to fine mud interference is first used to select niobium, which is the key to eliminating the desilicate, decarbonate and desludging processes; (5) a strong magnetic upgrading operation is introduced to further improve the grade of niobium concentrate; (6) an amine process is used to continue to recover niobium from the strong magnetic concentrate; and (7) the advantages of different reagents are fully utilized by combining the characteristics of the reagents with the properties of the ore and rationally optimizing the process flow.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] (1) The process flow is simplified, and the decarbonation, desilicate and desludging operations are eliminated, thus eliminating the niobium loss in these three operations from the source and ensuring the niobium recovery rate.

[0042] (2) Avoid using decarbonation and desilicate reagents, eliminate the influence of residual reagents on niobium flotation, and simplify the dehydration and de-drug operation.

[0043] (3) The introduction of high-intensity magnetic separation further reduces the impact of gangue minerals such as ilmenite on the concentrate grade.

[0044] (4) The amine process is used to recover niobium from the strong magnetic concentrate, ensuring the niobium recovery rate.

[0045] (5) When the grade of niobium concentrate is high, the niobium recovery rate is greatly improved, which realizes the effective utilization of resources and a mineral processing method for better recovery of niobium resources. It is particularly suitable for recovering pyrochlore from high-silicon and high-calcium carbonate-type niobium ores mainly composed of carbonates and silicates. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 It is a schematic diagram of the operation process of the present invention. DETAILED DESCRIPTION

[0047] The present invention is further described below with reference to specific examples, but the examples do not limit the present invention in any form. Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art.

[0048] Example 1:

[0049] The test sample is a carbonate-type pyrochlore niobium ore from Canada, with a niobium content of 1.15% and carbonate and silicate contents accounting for approximately 73%. This is a typical high-calcium and high-silicon carbonate-type niobium ore with carbonates and silicates as gangue minerals. The main steps are as follows:

[0050] (1) Weak magnetic separation operation:

[0051] The raw ore crushed to less than -2mm is ground to obtain a grinding product with a particle size of -0.1mm accounting for 77.63%. The slurry is adjusted to a concentration of 32% and enters a weak magnetic roughing separation with a magnetic field strength of 0.3T to obtain a weak magnetic roughing concentrate and a weak magnetic roughing tailings; the obtained weak magnetic roughing concentrate enters a weak magnetic concentration with a magnetic field strength of 0.2T to obtain a magnetite concentrate and a weak magnetic concentration tailings; the weak magnetic concentration tailings and the roughing tailings are combined into a weak magnetic tailings.

[0052] (2) Primary niobium flotation operation:

[0053] Adding a regulator, an activator and a collector to the obtained weak magnetic tailings in sequence for roughing to obtain a roughing concentrate and a roughing tailings; adding a collector to the roughing tailings for a first scavenging to obtain a first scavenging concentrate and a first scavenging tailings; adding a collector to the first scavenging tailings for a second scavenging to obtain a second scavenging concentrate and a second scavenging tailings, and the second scavenging tailings are used as niobium flotation tailings 1.

[0054] Inhibitors and collectors are sequentially added to the rougher concentrate obtained above, and a primary concentration is performed to obtain a primary concentrated concentrate and a primary concentrated tailings; inhibitors and collectors are sequentially added to the primary concentrated concentrate, and a secondary concentration is performed to obtain a secondary concentrated concentrate and a secondary concentrated tailings; inhibitors and collectors are sequentially added to the secondary concentrated concentrate, and a tertiary concentration is performed to obtain a tertiary concentrated concentrate and a tertiary concentrated tailings.

[0055] (3) Strong magnetic separation operation:

[0056] The tertiary concentrated concentrate obtained enters a strong magnetic separation with a magnetic field strength of 0.8T to obtain a strong magnetic concentrate and a strong magnetic tailings; the strong magnetic tailings is niobium concentrate 1.

[0057] (4) Secondary niobium flotation operation:

[0058] Adding a regulator and a collector to the obtained strong magnetic concentrate in sequence, performing roughing to obtain a roughing concentrate and a roughing tailing; adding a collector to the roughing tailing, performing a scavenging to obtain a scavenging concentrate and a scavenging tailing; the scavenging tailing is used as niobium flotation tailing 2.

[0059] Adjusters and collectors are sequentially added to the rougher concentrate obtained above, and a primary concentration is performed to obtain a primary concentrated concentrate and a primary concentrated tailings; adjusters and collectors are sequentially added to the primary concentrated concentrate, and a secondary concentration is performed to obtain a secondary concentrated concentrate and a secondary concentrated tailings; inhibitors and collectors are sequentially added to the secondary concentrated concentrate, and a tertiary concentration is performed to obtain a tertiary concentrated concentrate and a tertiary concentrated tailings; inhibitors and collectors are sequentially added to the tertiary concentrated concentrate, and a fourth concentration is performed to obtain a fourth concentrated concentrate and a fourth concentrated tailings; the fourth concentrated concentrate is niobium concentrate 2.

[0060] Among them, niobium flotation operation 1 can obtain niobium concentrate 1 with a niobium grade of 52.63% and a recovery rate of 76.16%. Niobium flotation operation 2 can obtain niobium concentrate 2 with a niobium grade of 54.66% and a recovery rate of 7.06%. The final total niobium recovery rate is 83.22%.

[0061] Example 2:

[0062] The test sample is a carbonate-type pyrochlore niobium ore from Brazil, with a niobium content of 1.07% and carbonate and silicate contents of approximately 67%. This is a typical high-calcium and high-silicon carbonate-type niobium ore with carbonates and silicates as gangue minerals. The main steps are as follows:

[0063] (1) Weak magnetic separation operation:

[0064] The raw ore crushed to less than -2mm is ground to obtain a grinding product with a particle size of -0.1mm accounting for 74.33%. The slurry is adjusted to a concentration of 35% and enters a weak magnetic roughing separation with a magnetic field strength of 0.1T to obtain a weak magnetic roughing concentrate and a weak magnetic roughing tailings. The obtained weak magnetic roughing concentrate enters a weak magnetic concentration with a magnetic field strength of 0.1T to obtain a magnetite concentrate and a weak magnetic concentration tailings. The weak magnetic concentration tailings and the roughing tailings are combined into a weak magnetic tailings.

[0065] (2) Primary niobium flotation operation:

[0066] Adding a regulator, an activator and a collector to the obtained weak magnetic tailings in sequence for roughing to obtain a roughing concentrate and a roughing tailings; adding a collector to the roughing tailings for a first scavenging to obtain a first scavenging concentrate and a first scavenging tailings; adding a collector to the first scavenging tailings for a second scavenging to obtain a second scavenging concentrate and a second scavenging tailings, and the second scavenging tailings are used as niobium flotation tailings 1.

[0067] Inhibitors and collectors are sequentially added to the rougher concentrate obtained above, and a primary concentration is performed to obtain a primary concentrated concentrate and a primary concentrated tailings; inhibitors and collectors are sequentially added to the primary concentrated concentrate, and a secondary concentration is performed to obtain a secondary concentrated concentrate and a secondary concentrated tailings; inhibitors and collectors are sequentially added to the secondary concentrated concentrate, and a tertiary concentration is performed to obtain a tertiary concentrated concentrate and a tertiary concentrated tailings.

[0068] (3) Strong magnetic separation operation:

[0069] The tertiary concentrated concentrate obtained enters a strong magnetic separation with a magnetic field strength of 0.6T to obtain a strong magnetic concentrate and a strong magnetic tailings; the strong magnetic tailings is niobium concentrate 1.

[0070] (4) Secondary niobium flotation operation:

[0071] Adding a regulator and a collector to the obtained strong magnetic concentrate in sequence, performing roughing to obtain a roughing concentrate and a roughing tailing; adding a collector to the roughing tailing, performing a scavenging to obtain a scavenging concentrate and a scavenging tailing; the scavenging tailing is used as niobium flotation tailing 2.

[0072] Adjusters and collectors are sequentially added to the rougher concentrate obtained above, and a primary concentration is performed to obtain a primary concentrated concentrate and a primary concentrated tailings; adjusters and collectors are sequentially added to the primary concentrated concentrate, and a secondary concentration is performed to obtain a secondary concentrated concentrate and a secondary concentrated tailings; inhibitors and collectors are sequentially added to the secondary concentrated concentrate, and a tertiary concentration is performed to obtain a tertiary concentrated concentrate and a tertiary concentrated tailings; inhibitors and collectors are sequentially added to the tertiary concentrated concentrate, and a fourth concentration is performed to obtain a fourth concentrated concentrate and a fourth concentrated tailings; the fourth concentrated concentrate is niobium concentrate 2.

[0073] Among them, niobium flotation operation 1 can obtain niobium concentrate 1 with a niobium grade of 51.32% and a recovery rate of 74.77%. Niobium flotation operation 2 can obtain niobium concentrate 2 with a niobium grade of 53.31% and a recovery rate of 8.25%. The final total niobium recovery rate is 83.02%.

[0074] Example 3:

[0075] The test sample is a carbonate-type pyrochlore niobium ore from Congo, Africa, with a niobium content of 0.86% and carbonate and silicate contents of approximately 76.88%. This is a typical high-calcium and high-silicon carbonate-type niobium ore with carbonate and silicate as gangue minerals. The main steps are as follows:

[0076] (1) Weak magnetic separation operation:

[0077] The raw ore crushed to less than -2mm is ground to obtain a grinding product with a particle size of -0.1mm accounting for 81.33%. The slurry is adjusted to a concentration of 33% and enters a weak magnetic roughing separation with a magnetic field strength of 0.2T to obtain a weak magnetic roughing concentrate and a weak magnetic roughing tailings; the obtained weak magnetic roughing concentrate enters a weak magnetic concentration with a magnetic field strength of 0.1T to obtain a magnetite concentrate and a weak magnetic concentration tailings; the weak magnetic concentration tailings and the roughing tailings are combined into a weak magnetic tailings.

[0078] (2) Primary niobium flotation operation:

[0079] Adding a regulator, an activator and a collector to the obtained weak magnetic tailings in sequence for roughing to obtain a roughing concentrate and a roughing tailings; adding a collector to the roughing tailings for a first scavenging to obtain a first scavenging concentrate and a first scavenging tailings; adding a collector to the first scavenging tailings for a second scavenging to obtain a second scavenging concentrate and a second scavenging tailings, and the second scavenging tailings are used as niobium flotation tailings 1.

[0080] Inhibitors and collectors are sequentially added to the rougher concentrate obtained above, and a primary concentration is performed to obtain a primary concentrated concentrate and a primary concentrated tailings; inhibitors and collectors are sequentially added to the primary concentrated concentrate, and a secondary concentration is performed to obtain a secondary concentrated concentrate and a secondary concentrated tailings; inhibitors and collectors are sequentially added to the secondary concentrated concentrate, and a tertiary concentration is performed to obtain a tertiary concentrated concentrate and a tertiary concentrated tailings.

[0081] (3) Strong magnetic separation operation:

[0082] The tertiary concentrated concentrate obtained enters a strong magnetic separation with a magnetic field strength of 0.8T to obtain a strong magnetic concentrate and a strong magnetic tailings; the strong magnetic tailings is niobium concentrate 1.

[0083] (4) Secondary niobium flotation operation:

[0084] Adding a regulator and a collector to the obtained strong magnetic concentrate in sequence, performing roughing to obtain a roughing concentrate and a roughing tailing; adding a collector to the roughing tailing, performing a scavenging to obtain a scavenging concentrate and a scavenging tailing; the scavenging tailing is used as niobium flotation tailing 2.

[0085] Adjusters and collectors are sequentially added to the rougher concentrate obtained above, and a primary concentration is performed to obtain a primary concentrated concentrate and a primary concentrated tailings; adjusters and collectors are sequentially added to the primary concentrated concentrate, and a secondary concentration is performed to obtain a secondary concentrated concentrate and a secondary concentrated tailings; inhibitors and collectors are sequentially added to the secondary concentrated concentrate, and a tertiary concentration is performed to obtain a tertiary concentrated concentrate and a tertiary concentrated tailings; inhibitors and collectors are sequentially added to the tertiary concentrated concentrate, and a fourth concentration is performed to obtain a fourth concentrated concentrate and a fourth concentrated tailings; the fourth concentrated concentrate is niobium concentrate 2.

[0086] Among them, niobium flotation operation 1 can obtain niobium concentrate 1 with a niobium grade of 49.82% and a recovery rate of 74.77%. Niobium flotation operation 2 can obtain niobium concentrate 2 with a niobium grade of 51.31% and a recovery rate of 10.32%. The final total niobium recovery rate is 85.09%.

[0087] Comparative Example 1:

[0088] This comparative example provides a conventional pyrochlore beneficiation method. The raw ore is the same as that in Example 2. The beneficiation steps follow a conventional carbonate-type pyrochlore beneficiation process and reagents, namely, grinding, decarbonation, desilicate, weak magnetic separation, desludging, and flotation for niobium. The decarbonization reagents are fatty acids, sodium hydroxide, and starch, and the desiliconization reagents are etheramines, sodium hydroxide, and starch. The weak magnetic separation process parameters are consistent with those in Example 3. An amine collector and fluosilicic acid are used for flotation of niobium. The resulting niobium concentrate has a niobium grade of 52.42% and a recovery of 63.11%. While the niobium grades of the two concentrates are similar, the recovery differs by approximately 19.91%. Furthermore, the pH of the conventional niobium flotation process is approximately 10 before flotation, and 2.5-6 during flotation. However, after repeated slurry adjustment with strong acids and bases, the pH of the first flotation stage of the new process is approximately 7.0, significantly improving the operating environment. The pH of the second flotation stage of niobium is 2.5-6.

[0089] Table 1 below shows the types and dosages of the corresponding drugs in the three examples, where:

[0090] In Example 1, the regulator for the primary niobium flotation operation was prepared with citric acid and modified water glass in a ratio of 4:2; the collector was prepared with C7-9 hydroxamic acid, benzohydroxamic acid, and oxidized paraffin soap in a ratio of 2:6:1; the activator was lead nitrate; the inhibitor was carboxymethyl cellulose; and the collector for the secondary niobium flotation operation was octadecylamine acetate.

[0091] In Example 2, the regulator for the primary niobium flotation operation was prepared with quinic acid, citric acid, and modified water glass in a ratio of 4:4:2; the collector was prepared with alkyl hydroxamic acid, benzohydroxamic acid, and oxidized paraffin soap in a ratio of 3:7:1; the activator was lead chloride; the inhibitor was tannic acid; and the collector for the secondary niobium flotation operation was dodecylamine acetate.

[0092] In Example 3, the regulator for the primary niobium flotation operation was prepared with oxalic acid and modified water glass in a ratio of 3:1; the collector was prepared with benzohydroxamic acid and oxidized paraffin soap in a ratio of 7:1; the activator was lead nitrate; the inhibitor was lignin; and the collector for the secondary niobium flotation operation was coconut amine.

[0093] Table 1

[0094]

[0095]

Claims

1. A beneficiation method for recovering pyrochlore from high-silicon and high-calcium carbonate-type niobium ore, characterized in that: The method comprises the following steps: (1) Weak magnetic separation: The grinding products are subjected to weak magnetic roughing and weak magnetic concentrating operations to obtain magnetite concentrate and weak magnetic tailings; (2) One-time niobium flotation operation: add pH adjusting agent to the weak magnetic tailings in step (1) to carry out one-time niobium flotation operation, adjust the pH of the pulp to 7-9; add inhibitor, activator and collector to carry out one to three times of concentrating; add inhibitor and collector to carry out one to two times of scavenging to obtain flotation niobium concentrate and niobium tailings 1; the amount of collector added in the roughing process is 1500-2000 g / ton; (3) Strong magnetic separation: The flotation niobium concentrate obtained in step (2) is subjected to strong magnetic separation to obtain niobium concentrate 1 and strong magnetic concentrate; (4) Secondary niobium flotation: The strong magnetic concentrate obtained in step (3) is subjected to secondary niobium flotation by adding fluorosilicic acid, and the pH value of the pulp is adjusted to 5; a collector is added for a roughing operation; fluorosilicic acid and a collector are added for one to four fine cleaning operations; a collector is added for a scavenging operation to obtain niobium concentrate 2 and niobium tailings 2; the amount of collector added during the roughing operation is 600 to 1000 g / ton; The collecting agent in step (2) is selected from C 7-9 One or more of alkyl isoximic acid, aryl hydroximic acid, benzohydroximic acid, and octyl hydroximic acid are prepared with oxidized paraffin soap in a ratio of (10-20):1; The collector in step (4) is dodecylamine acetate, octadecylamine acetate or coconut amine; In steps (2) and (4), the amount of collector added during the first selection is 160 to 200 g / ton; the amount of collector added during the second selection is 80 to 120 g / ton; and the amount of collector added during the third and fourth selections is 40 to 80 g / ton.

2. The mineral processing method according to claim 1, characterized in that: The pH adjuster in step (2) is selected from one or more of oxalic acid, citric acid, quinic acid, salicylic acid, and tartaric acid and prepared with modified water glass, and the preparation ratio is (3-5):1; the inhibitor is one or more of CMC, dextrin, tannic acid, and lignin; and the activator is lead nitrate and / or lead chloride.

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