CN116099650A - Mineral processing method for recovering pyrochlore from high-silicon and high-calcium carbonate niobium ore - Google Patents

Abstract

The invention discloses a beneficiation method for recovering pyrochlore from high-silicon high-calcium carbonate niobium ore, which comprises the following steps: after pulp mixing of the ground ore product, carrying out rough-fine weak magnetic separation to obtain magnetite concentrate and weak magnetic tailings; the weak magnetic tailings undergo one-coarse three-fine two-sweep niobium flotation to obtain flotation niobium concentrate and flotation niobium tailings 1; carrying out one-coarse one-fine strong magnetic separation on the flotation niobium concentrate to obtain niobium concentrate 1 and strong magnetic concentrate; and carrying out one-coarse four-fine one-sweep niobium flotation on the strong magnetic concentrate to obtain niobium concentrate 2 and floating niobium tailings 2. By utilizing the characteristics of different types of niobium flotation agents, the invention reasonably optimizes the process flow, simplifies the processes of desilication, decarbonization (dephosphorization and decalcification), desliming and the like in the traditional niobium flotation process, obviously shortens the niobium flotation flow, reduces the niobium loss before niobium flotation, fundamentally eliminates the problem of low niobium recovery rate, and greatly improves the niobium recovery rate. Finally, the niobium concentrate with the niobium grade of more than 50% and high recovery rate can be obtained.

Description

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

Technical Field

The 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

Niobium is an important rare metal. Adding niobium to other metals can make various high-temperature resistant and high-strength special 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.

Niobium minerals mainly exist in granite pegmatite and carbonate deposits. Although there are many types of niobium minerals, only about 10 types are used as industrial mineral raw materials, namely, niobium iron ore-tantalite series minerals, brown yttrium niobium ore, calcite, niobium calcite, niobium iron rutile, pyrochlore, etc. Among them, granite pegmatite is mainly composed of tantalum and niobium, but the niobium grade is low. Carbonate pyrochlore has a higher niobium grade and is the main source of niobium metal. 95% of the world's niobium supply comes from pyrochlore. Therefore, the development and utilization of carbonate pyrochlore plays a vital role in increasing the global niobium supply.

The Alaksa mine is a weathered laterite carbonate-type pyrochlore mine, and its ore contains only a small amount of carbonate and silicate minerals, mainly fine mud and magnetite minerals. The main method for recovering pyrochlore from it is: the original ore is first subjected to magnetic separation after grinding, and the non-magnetic minerals are subjected to a desliming process. The desliming operation uses a three-stage cyclone group to remove fine mud below 5μm. The desliming process has a slime yield of about 12%, and the niobium loss is 5% to 7%. Sodium fluorosilicate or fluorosilicic acid is used as an activator for floating niobium, and hydrochloric acid is used to adjust the pH to 2.5 to 3.5. Amine cationic collectors are used to finally obtain a niobium concentrate with a niobium grade of 55% to 60%. This ore basically does not contain carbonate minerals that consume acid, so the pH can be directly adjusted to acidic without considering the removal of carbonate minerals; at the same time, it contains a small amount of silicate minerals, and amine collectors can be used directly without desiliconization, but the fine mud yield in this process is relatively large, and niobium is lost in the fine mud.

The Niobek ore is an alkaline carbonate pyrochlore, with carbonate minerals accounting for 60% and silicate minerals accounting for 20%. A grinding system consisting of a rod mill + ball mill + spiral classifier and a vibrating screen is used on site to reduce the content of fine mud. The grinding product is desludged by a two-stage cyclone, and a fatty acid collector is added to the desludged product for carbonate flotation; the flotation tailings are subjected to weak magnetic iron removal; etheramine collectors are added to the weak magnetic tailings, and sodium hydroxide and starch are used as inhibitors for desiliconization; diamine is used as a collector for the desiliconized tailings, and hydrochloric acid is added to adjust the pH to 2.7. After multiple selections, a niobium concentrate containing 45% to 50% niobium is obtained. After the niobium concentrate is leached with hydrochloric acid to remove carbonates and phosphates, a pyrochlore concentrate with a niobium grade of 55% to 60% is finally obtained. This process is cumbersome, and each gangue mineral is processed before flotation of niobium, resulting in a large cumulative pyrochlore loss. In addition, in the pyrochlore flotation stage, the dissolution of carbonates under high acidity conditions consumes a large amount of acid, thereby increasing production costs.

The Katalao mine is a laterite-type pyrochlore, containing a large amount of mica minerals 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 silicate removal, using etheramine as the collector and sodium hydroxide + starch as the inhibitor; the obtained flotation tailings are added with fatty acid collectors for decarbonation operation; the obtained flotation tailings enter the niobium selection operation, using amines as collectors, hydrochloric acid as adjusters, and sodium fluorosilicate as inhibitors. 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 an adjusting agent. 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.

In summary, due to the large number of associated mineral components, the beneficiation process of pyrochlore is very complicated. The flotation process of weathered ore and high-silicon and high-calcium carbonate-type pyrochlore is basically similar, all of which are desludging-reverse flotation silicate-reverse flotation decarbonation-magnetic separation-pyrochlore flotation-sulfide flotation-leaching dephosphorization process. Amine collectors are sensitive to fine mud. The presence of muddy particles will reduce the flotation efficiency of pyrochlore. Desludging is required before flotation, and the niobium loss during the desludging process is large. Reverse flotation to remove carbonate is mainly affected by strong acidic sorting conditions. When there are more carbonate minerals, a large amount of hydrochloric acid or fluorosilicic acid needs to be added to adjust the pH. At the same time, a large number of bubbles will be generated during the pH adjustment process, which will affect the flotation process. Reverse flotation to remove carbonate is mainly because the silicate minerals in the ore are susceptible to the action of amine collectors and need to be removed. Only then will it be beneficial to the enrichment of pyrochlore and finally obtain qualified concentrate.

At present, the main high-silicon and high-calcium carbonate-type pyrochlore production process has the following major problems: 1. The beneficiation process of pyrochlore is complicated, and the loss of niobium minerals at each stage is inevitable. The cumulative effect causes a large amount of metallic niobium to be lost before niobium flotation. The niobium recovery rate in the final niobium concentrate is only 50% to 60%, and nearly 30% of niobium is lost in operations such as desludging, decarbonation, desilicate, deagent dehydration, etc. 2. The pH difference before and after the niobium flotation operation is large, from strong alkalinity to strong acidity, the working environment is poor, the acid consumption is high, and the equipment is seriously corroded. 3. The residual reagents of decarbonation and desilicate will affect the flotation of niobium, resulting in the increase of deagent dehydration operations after each operation, and some niobium will also be lost. The niobium flotation reagent system is the main reason for the cumbersomeness of the entire process. The adjustment and optimization of the niobium flotation reagent system is the key to simplifying the entire process and improving the niobium recovery rate.

Summary of the invention

The purpose of the present invention is to provide an improved beneficiation method for the current beneficiation process for recovering pyrochlore from high-silicon and high-calcium carbonate-type niobium ore, which has the problems of long process flow and low niobium recovery rate. The process of weak magnetic iron removal-flotation selection of niobium-strong magnetic impurity removal-flotation selection of niobium is used to treat such carbonate-type niobium ore, forming a reasonable process method formulated according to the properties of the ore and the properties of the reagent. The method greatly simplifies the process flow, improves the working environment of niobium flotation, and increases the niobium recovery rate, thereby realizing the effective recovery of niobium resources.

The technical solution of the present invention comprises the following steps:

S1. 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.

S2. One-time niobium flotation operation: Add pH adjuster to the weak magnetic tailings in S1 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 roughing selection; add inhibitor and collector to carry out one to three times of fine selection; add collector to carry out one to two times of scavenging selection, and obtain flotation niobium concentrate and niobium tailings 1. The reagent used in this step is a highly selective fatty acid chelating collector that is resistant to fine mud interference and has weak collection ability for gangue minerals, especially silicate minerals. The inhibitor is weak acid, and the pH is weakly alkaline during operation. The carbonate minerals will not interfere with the flotation, and it is suitable for the flotation pulp of high silicon and high calcium.

S3. Strong magnetic separation: The flotation niobium concentrate obtained in S2 is subjected to strong magnetic separation to obtain niobium concentrate 1 and strong magnetic concentrate. This step is introduced after the first flotation concentrate to achieve multiple goals such as reducing the magnetic separation processing volume, improving the quality of niobium concentrate, fine particle size and magnetic mineral classification, and creating conditions for subsequent secondary recovery of niobium.

S4. Secondary niobium flotation operation: Add an adjusting agent (fluorosilicic acid is used in this step) to the strong magnetic concentrate obtained in S3 for secondary niobium flotation operation, adjust the pH of the pulp to 5; add a collector for a roughing selection; add an adjusting agent and a collector for one to four fine selections; add a collector for a scavenging selection to obtain niobium concentrate 2 and niobium tailings 2. The reagent used in this step is an amine collector that is sensitive to fine mud and has a weak ability to capture ilmenite minerals. The inhibitor used is a strong acid. In the process of strong magnetic separation, acid-consuming gangue minerals do not enter this operation, which greatly reduces the acid consumption.

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%.

The present invention is based on the properties of the ore, adjusts the reagent system for niobium flotation operations, utilizes the different characteristics of two types of collectors, and rationally designs the process to fundamentally eliminate the loss of niobium in each operation. The chelating combined collector has a neutral operating environment, is highly resistant to fine mud, and has basically no collecting effect on silicate minerals. This series of characteristics realizes the elimination of processes such as desilicate, decarbonate, and desludging before niobium flotation, but it also has a certain collecting effect on magnetic minerals containing titanium and iron. Subsequently, it is necessary to remove magnetic impurity minerals such as titanium and iron from the flotation niobium concentrate through strong magnetic operations to further improve the niobium grade. After strong magnetic separation, there is still some niobium in the strong magnetic concentrate, which is mainly magnetic minerals containing titanium and iron. After strong magnetic separation, the carbonate, silicate minerals and fine mud content 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 the process flow, the desilicate, decarbonate, desludging, de-drug and dehydration operations required by the amine process are eliminated, and the quality of the flotation niobium concentrate obtained in the first stage is improved. The niobium in the obtained strong magnetic concentrate is 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 is obtained.

Preferably, the grinding in step S1 is: grinding the raw ore until the -0.1 mm particles account for 72-82% of the total particles. More preferably, the grinding fineness -0.1 mm particle size content is reduced to less than 78%, which can simplify the number of grinding stages, reduce the number of mills, and greatly reduce the on-site electricity cost.

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

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.

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

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.

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.

In the tertiary concentration 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.

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

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

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

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.

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

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.

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.

In the three concentrations of 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.

In the fourth 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.

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

The amount of each additive added can be appropriately adjusted with reference to the amount commonly used in the industry, and the magnetic field strength of weak magnetism and strong magnetism can be adjusted with reference to industry data.

The collector in step S2 is a new type of chelating combined collector that is highly effective in resisting interference from fine mud; 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.

Preferably, the novel chelating combined collector with high efficiency and resistance to fine mud interference is selected from at least one of _C7-9 alkyl isoxime acid, aryl hydroxamic acid, benzohydroxamic acid or octyl hydroxamic acid, and 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 with modified water glass is 3-5:1; the activator is lead nitrate and/or lead chloride.

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.

The present invention aims at the outstanding problems of long process, serious niobium loss in each operation, and great influence of residual reagents in the process of pyrochlore recovery of high-silicon and high-calcium carbonate niobium ore. Through a reasonable niobium flotation reagent system, the goals of eliminating desilicate, decarbonate, and desludging, improving the niobium flotation reagent system and simplifying the process flow are achieved, and the loss of niobium in desilicate, carbonate operations and fine mud is reduced. At the same time, strong magnetic separation is introduced to improve the quality of niobium concentrate, and niobium minerals are continuously recovered from the strong magnetic concentrate to obtain high-grade and high-recovery niobium concentrate.

The present invention is different 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 processes of desilicate, decarbonate and desludging; (5) a strong magnetic upgrading operation is introduced to further improve the grade of niobium concentrate; (6) the 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 optimizing the process flow in a reasonable manner.

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

(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.

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

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

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

(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 beneficiation 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

FIG. 1 is a schematic diagram of the operation flow of the present invention.

DETAILED DESCRIPTION

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.

Embodiment 1:

The test ore sample is a carbonate-type pyrochlore niobium ore in Canada, in which the niobium content is 1.15%, and the carbonate and silicate content accounts for about 73%. It 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:

(1) Weak magnetic separation operation:

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%, which is slurried 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.

(2) Primary niobium flotation operation:

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.

To the rougher concentrate obtained above, inhibitors and collectors are sequentially added to perform a primary concentration to obtain a primary concentrated concentrate and a primary concentrated tailings; to the primary concentrated concentrate, inhibitors and collectors are sequentially added to perform a secondary concentration to obtain a secondary concentrated concentrate and a secondary concentrated tailings; to the secondary concentrated concentrate, inhibitors and collectors are sequentially added to perform a tertiary concentration to obtain a tertiary concentrated concentrate and a tertiary concentrated tailings.

(3) Strong magnetic separation operation:

The tertiary concentrated concentrate obtained enters into 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.

(4) Secondary niobium flotation operation:

Adding adjusting agent and collecting agent to the obtained strong magnetic concentrate in sequence, roughing is carried out to obtain roughing concentrate and roughing tailings; adding collecting agent to the roughing tailings, performing a scavenging, obtaining a scavenging concentrate and a scavenging tailings; the scavenging tailings are used as niobium flotation tailings 2.

To the rougher concentrate obtained above, adjusters and collectors are added in sequence to perform a primary concentration to obtain a primary concentrated concentrate and a primary concentrated tailings; adjusters and collectors are added in sequence to the primary concentrated concentrate to perform a secondary concentration to obtain a secondary concentrated concentrate and a secondary concentrated tailings; inhibitors and collectors are added in sequence to the secondary concentrated concentrate to perform a tertiary concentration to obtain a tertiary concentrated concentrate and a tertiary concentrated tailings; inhibitors and collectors are added in sequence to the tertiary concentrated concentrate to perform a fourth concentration to obtain a fourth concentrated concentrate and a fourth concentrated tailings; the fourth concentrated concentrate is niobium concentrate 2.

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%, and 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%.

Embodiment 2:

The test ore sample is a carbonate-type pyrochlore niobium ore in Brazil, in which the niobium content is 1.07%, and the carbonate and silicate content accounts for about 67%. It 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:

(1) Weak magnetic separation operation:

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%, which is slurried 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.

(2) Primary niobium flotation operation:

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.

To the rougher concentrate obtained above, inhibitors and collectors are sequentially added to perform a primary concentration to obtain a primary concentrated concentrate and a primary concentrated tailings; to the primary concentrated concentrate, inhibitors and collectors are sequentially added to perform a secondary concentration to obtain a secondary concentrated concentrate and a secondary concentrated tailings; to the secondary concentrated concentrate, inhibitors and collectors are sequentially added to perform a tertiary concentration to obtain a tertiary concentrated concentrate and a tertiary concentrated tailings.

(3) Strong magnetic separation operation:

The tertiary concentrated concentrate obtained enters into 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.

(4) Secondary niobium flotation operation:

Adding adjusting agent and collecting agent to the obtained strong magnetic concentrate in sequence, roughing is carried out to obtain roughing concentrate and roughing tailings; adding collecting agent to the roughing tailings, performing a scavenging, obtaining a scavenging concentrate and a scavenging tailings; the scavenging tailings are used as niobium flotation tailings 2.

To the rougher concentrate obtained above, adjusters and collectors are added in sequence to perform a primary concentration to obtain a primary concentrated concentrate and a primary concentrated tailings; adjusters and collectors are added in sequence to the primary concentrated concentrate to perform a secondary concentration to obtain a secondary concentrated concentrate and a secondary concentrated tailings; inhibitors and collectors are added in sequence to the secondary concentrated concentrate to perform a tertiary concentration to obtain a tertiary concentrated concentrate and a tertiary concentrated tailings; inhibitors and collectors are added in sequence to the tertiary concentrated concentrate to perform a fourth concentration to obtain a fourth concentrated concentrate and a fourth concentrated tailings; the fourth concentrated concentrate is niobium concentrate 2.

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%, and 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%.

Embodiment 3:

The test ore sample is a carbonate-type pyrochlore niobium ore in Congo, Africa, with a niobium content of 0.86%, and carbonate and silicate contents accounting for about 76.88%. It 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:

(1) Weak magnetic separation operation:

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%, which is slurried 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.

(2) Primary niobium flotation operation:

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.

To the rougher concentrate obtained above, inhibitors and collectors are sequentially added to perform a primary concentration to obtain a primary concentrated concentrate and a primary concentrated tailings; to the primary concentrated concentrate, inhibitors and collectors are sequentially added to perform a secondary concentration to obtain a secondary concentrated concentrate and a secondary concentrated tailings; to the secondary concentrated concentrate, inhibitors and collectors are sequentially added to perform a tertiary concentration to obtain a tertiary concentrated concentrate and a tertiary concentrated tailings.

(3) Strong magnetic separation operation:

The tertiary concentrated concentrate obtained enters into 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.

(4) Secondary niobium flotation operation:

Adding adjusting agent and collecting agent to the obtained strong magnetic concentrate in sequence, roughing is carried out to obtain roughing concentrate and roughing tailings; adding collecting agent to the roughing tailings, performing a scavenging, obtaining a scavenging concentrate and a scavenging tailings; the scavenging tailings are used as niobium flotation tailings 2.

To the rougher concentrate obtained above, adjusters and collectors are added in sequence to perform a primary concentration to obtain a primary concentrated concentrate and a primary concentrated tailings; adjusters and collectors are added in sequence to the primary concentrated concentrate to perform a secondary concentration to obtain a secondary concentrated concentrate and a secondary concentrated tailings; inhibitors and collectors are added in sequence to the secondary concentrated concentrate to perform a tertiary concentration to obtain a tertiary concentrated concentrate and a tertiary concentrated tailings; inhibitors and collectors are added in sequence to the tertiary concentrated concentrate to perform a fourth concentration to obtain a fourth concentrated concentrate and a fourth concentrated tailings; the fourth concentrated concentrate is niobium concentrate 2.

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%, and 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%.

Comparative Example 1:

This comparative example provides an existing pyrochlore beneficiation method, the original ore is the same as that in Example 2, the beneficiation steps are the traditional carbonate type pyrochlore beneficiation process and reagents, namely grinding-decarbonation-desilicate-weak magnetic separation-desludging-flotation selection of niobium, wherein the decarbonization reagents are fatty acids, sodium hydroxide, and starch, the desiliconization reagents are etheramines, sodium hydroxide, and starch, the parameters of the weak magnetic separation process are consistent with those in Example 3, and the flotation selection of niobium uses amine collectors and fluorosilicic acid. In the final niobium concentrate product, the niobium grade is 52.42%, and the recovery rate is 63.11%. The niobium grades of the two concentrates are close, but the recovery rates differ by nearly 19.91%. Moreover, the pH before niobium flotation in the traditional process is about 10, and the niobium flotation is 2.5-6. After repeated slurry adjustment with strong acid and strong alkali, the pH of the first stage of flotation in the new process is about 7.0, and the working environment is significantly improved. The pH of the second stage of niobium flotation is 2.5-6.

Table 1 below shows the corresponding drug types and dosages of the three embodiments, where:

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

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

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

Table 1

Claims (2)

1. A 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 magnetic concentrate and weak magnetic tailings; (2) One niobium flotation operation: add a pH adjuster to the weak magnetic tailings in step (1) to carry out a niobium flotation operation, adjust the pH of the pulp to 7-9; add an inhibitor, an activator, and a collector to carry out a roughing operation; add an inhibitor and a collector to carry out one to three fine cleaning operations; add a collector to carry out one to two scavenging operations to obtain a flotation niobium concentrate and a niobium tailings 1; the amount of the collector added during the roughing operation is 1500-2000 g/ton; (3) Strong magnetic separation: subjecting the flotation niobium concentrate obtained in step (2) to strong magnetic separation to obtain niobium concentrate 1 and strong magnetic concentrate; (4) Secondary niobium flotation operation: Add fluorosilicic acid to the strong magnetic concentrate obtained in step (3) for secondary niobium flotation operation, adjust the pH value of the slurry to 5; add a collector for a roughing operation; add fluorosilicic acid and a collector for one to four times of fine concentration; add a collector 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 collector in step (2) is selected from one or more of _C7-9 alkyl isoxime, aryl hydroxamic acid, benzohydroxamic acid, octyl hydroxamic acid and oxidized paraffin soap, and the preparation ratio is (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 is 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.

Images