Separation and quality improvement method for fine fluorite in rare earth tailings

Abstract

The invention discloses a method for separating and upgrading fine fluorite in rare earth tailings, which belongs to the technical field of fluorite production, and comprises the following steps of: mixing the rare earth tailings, and removing barite and pre-enriching by a hydrocyclone to obtain two products, namely settled sand and overflow; the desilting product is subjected to size mixing, a regulator, a fluorite activating agent, an inhibitor and a fluorite collecting agent are added in sequence, and treated ore pulp is obtained; adding the ore pulp into a flotation machine to obtain flotation foam and roughing tailings; the flotation froth is sequentially subjected to three times of fluorite concentration, and a first kind of fine-grain fluorite is obtained; and mixing the roughing tailings with middlings obtained by the later two times of fluorite concentration, performing size mixing, adding a regulator, a fluorite activating agent and an inhibitor, and performing scavenging to obtain a second kind of fine-grain fluorite and scavenged tailings. The separation efficiency in the flotation process is improved, the recovery rate and grade of the fine fluorite are improved, and meanwhile environmental pollution and resource waste are reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of fluorite production, and specifically relates to a method for separating and preparing fluorite from rare earth tailings, and in particular to a method for separating and improving fine-grained fluorite in rare earth tailings. Background Art

[0002] Fluorite (CaF2), also known as fluorspar, is a common mineral in nature. It is widely used in many fields such as metallurgy, chemical industry, glass and ceramics, and generally coexists with many other minerals.

[0003] Rare earth tailings are solid waste generated during the mining and extraction of rare earth minerals, usually containing a large amount of fine-grained fluorite. Recovering fine-grained fluorite from rare earth tailings can not only improve resource utilization, but also reduce environmental pollution caused by tailings storage. However, the fine-grained fluorite in rare earth tailings is fine and contains a large amount of fine-grained barite and carbonate minerals, making its separation and quality improvement technically difficult.

[0004] At present, the traditional separation method of fine-grained fluorite in rare earth tailings mainly relies on flotation technology. However, the traditional flotation process faces many challenges when treating rare earth tailings, such as similar flotation properties of fluorite and associated minerals, large dosage of reagents, poor selectivity, serious environmental pollution, etc., resulting in low recovery rate and grade (referring to the ratio of the content of useful elements or their compounds in the ore); at the same time, fine-grained fluorite is prone to "mudification", which further reduces the flotation effect.

[0005] More specifically, the main reasons why fluorite is difficult to separate from barite (BaSO4) and carbonate minerals (such as calcite CaCO3) in rare earth tailings are:

[0006] Similar surface charge and hydrophilicity: Fluorite, barite and carbonate minerals have similar surface charge and hydrophilicity in water, especially under neutral to weakly alkaline conditions, their surface potentials are relatively close. This similarity makes it difficult for conventional flotation agents to effectively selectively adsorb and separate them.

[0007] Similar flotation properties: Under conventional flotation conditions, the flotation properties of fluorite are similar to those of carbonate minerals (such as calcite CaCO3) and barite. Anionic collectors (such as fatty acid salts) commonly used in fluorite flotation can also undergo adsorption reactions with carbonate minerals and barite, causing them to be floated out together, making it difficult to achieve selective separation of a single mineral.

[0008] Influence of coexisting impurities: Fluorite often coexists closely with barite and carbonate minerals. The mutual interference of fine particles and impurities further increases the difficulty of flotation separation. In the actual flotation process, these minerals are prone to "mudification" and adhere to each other, which greatly reduces the flotation efficiency.

[0009] Therefore, a new method is urgently needed to solve the inefficient separation problem existing in the existing technology in order to improve the recovery rate and grade of fine-grained fluorite. Summary of the invention

[0010] The purpose of the present invention is to provide a method for separating and upgrading fine-grained fluorite in rare earth tailings in order to solve the above-mentioned problems. The method strengthens the flotation of fluorite and promotes the separation of fluorite (CaF2) from barite (BaSO4) and carbonate minerals (such as calcite CaCO3), thereby achieving low-drug selection of fluorite and obtaining high-grade fluorite concentrate.

[0011] The present invention achieves the above-mentioned purpose through the following technical solutions:

[0012] A method for separating and upgrading fine-grained fluorite in rare earth tailings comprises the following steps:

[0013] Step 1, slurrying the rare earth tailings in a mixing barrel, adjusting the slurry concentration to 20%, and obtaining two products of hydrocyclone sedimentation and overflow after barite removal pre-enrichment treatment by a hydrocyclone;

[0014] Step 2, slurrying the sedimentation product obtained in step 1, adjusting the slurry concentration to 25%-30%, and adding a regulator, a fluorite activator, an inhibitor I and a fluorite collector to the slurry in sequence to obtain a treated slurry;

[0015] Step 3, adding the slurry obtained in step 2 to a flotation machine to perform rough separation of fluorite to obtain flotation foam and rough separation tailings;

[0016] Step 4, adding inhibitor II to the flotation foam obtained in step 3 to perform the first fluorite concentration to obtain fluorite concentrate I and middlings I;

[0017] Step 5, adding inhibitor II to the fluorite concentrate I obtained in step 4, performing a second fluorite concentration, and obtaining fluorite concentrate II and middlings II;

[0018] Step 6, adding inhibitor II to the fluorite concentrate II obtained in step 5, and performing a third fluorite concentration to obtain fluorite concentrate III and intermediate ore III, wherein the fluorite concentrate III is the first fine-grained fluorite;

[0019] Step 7, the rougher tailings obtained in step 3, the middling ore II obtained in step 5 and the middling ore III obtained in step 6 are mixed and slurried to adjust the slurry concentration to 25%-30%, and then the regulator, fluorite activator and inhibitor III are added to perform scavenging to obtain sub-concentrate and scavenged tailings, wherein the sub-concentrate is the second fine-grained fluorite, the first fine-grained fluorite and the second fine-grained fluorite can be mixed and used or used independently, and the quality and fineness of the first fine-grained fluorite and the second fine-grained fluorite are generally close, but not necessarily the same.

[0020] Preferably, in step 1, the stirring frequency of the slurry adjustment is 50 Hz, the stirring time is 10 minutes, the frequency of the slurry pump used to provide high-pressure slurry for the hydrocyclone is 40 Hz, the feed pressure is 0.285 MPa, and the specification of the hydrocyclone is Φ20 cm.

[0021] Preferably, in step 2, inhibitor I is one or more of water glass, sodium humate, sulfuric acid, aluminum sulfate and sodium hexametaphosphate, the regulator is sodium carbonate, the fluorite activator is an ammonia activator, and the fluorite collector is a combination of fatty acid and sodium oleate. Preferably, the mass ratio of the fatty acid to the sodium oleate is (10-50): (50-90).

[0022] Preferably, in step 2, the amount of the adjusting agent is 300-500 g / t; the amount of the inhibitor I is 200-400 g / t; the amount of the fluorite activator is 400-700 g / t; and the amount of the fluorite collector is 300-500 g / t.

[0023] Preferably, in step 4, step 5 and step 6, inhibitor II is modified water glass and / or carboxymethyl cellulose.

[0024] Preferably, the amount of inhibitor II in step 4 is 50-200 g / t; the amount of inhibitor II in step 5 is 50-150 g / t; and the amount of inhibitor II in step 6 is 10-100 g / t.

[0025] Preferably, in step 7, the adjusting agent is sodium carbonate, the fluorite activator is an ammonia activator, and the inhibitor III is a combination of the inhibitor I in step 2 and the inhibitor II in steps 4 to 6. Preferably, the mass ratio of inhibitor I to inhibitor II is (30-50): (50-70).

[0026] In step 7, the amount of the adjusting agent is 100-300 g / t, the amount of the inhibitor III is 100-300 g / t, and the amount of the fluorite activator is 100-300 g / t.

[0027] All the above-mentioned units "g / t" represent the amount of raw materials corresponding to each ton of raw ore, i.e. rare earth tailings, in grams.

[0028] The beneficial effects of the present invention are:

[0029] The present invention makes full use of the characteristic that barite in rare earth tailings is mainly distributed in the fine particle part due to over-grinding, and removes it by classification through a hydrocyclone, which helps to simplify the flotation process and reduce the amount of reagents used in the flotation process. By using a specific reagent combination and optimized process parameters, the selective capture of fine-grained fluorite is enhanced, the separation efficiency in the flotation process is improved, the recovery rate and grade of fine-grained fluorite are improved, and environmental pollution and resource waste are reduced.

[0030] The more specific beneficial effects of the present invention are:

[0031] (1) Significantly improved separation efficiency: The present invention significantly improves the separation selectivity of fluorite and gangue minerals (such as barite, carbonate minerals, etc.) by adopting a combined gravity-flotation process and a specific reagent combination. The optimized reagent system and flotation conditions effectively inhibit the flotation of other gangue minerals, improve the fluorite recovery rate, and significantly improve the comprehensive recovery efficiency of fluorite.

[0032] (2) Product quality upgrade and improved efficiency of comprehensive resource utilization: The method of the present invention can more effectively separate fine-grained fluorite from rare earth tailings, reduce the inclusion of gangue minerals, and improve the quality of fluorite concentrate; compared with traditional flotation methods, the present invention can obtain higher-grade fluorite products while maintaining a higher recovery rate, meeting the application requirements of higher quality.

[0033] (3) Reducing production costs: The present invention effectively reduces the consumption of reagents required in the flotation process, thereby reducing production costs. At the same time, since the present method improves the sorting efficiency and reduces the need for multiple flotation and repeated treatments, it further saves energy and resource consumption in production.

[0034] (4) Simple process and convenient operation: The process flow of the present invention is simple and clear, easy to apply industrially, and its operating steps are optimized and reasonable. It has low requirements for equipment and process conditions and strong adaptability. It can be modified and applied on existing mineral processing plant facilities without large-scale equipment replacement and investment. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic flow chart of the method for separating and upgrading fine-grained fluorite in rare earth tailings according to the present invention. DETAILED DESCRIPTION

[0036] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0037] like Figure 1 As shown, the method for separating and upgrading fine-grained fluorite in rare earth tailings of the present invention comprises the following steps:

[0038] Step 1, slurrying the rare earth tailings in a mixing barrel, adjusting the slurry concentration to 20%, and obtaining two products of hydrocyclone sedimentation and overflow after barite removal pre-enrichment treatment by a hydrocyclone; the stirring frequency of the slurrying is preferably 50HZ, the stirring time is preferably 10 minutes, the frequency of the slurry pump for providing high-pressure slurry for the hydrocyclone is preferably 40HZ, the feed pressure is preferably 0.285Mpa, and the specification of the hydrocyclone is preferably Φ20cm;

[0039] Step 2, slurrying the sedimentation product obtained in step 1, adjusting the pulp concentration to 25%-30%, and adding a regulator, a fluorite activator, an inhibitor I and a fluorite collector to the pulp in order to obtain a treated pulp; the inhibitor I is preferably one or more of water glass, sodium humate, sulfuric acid, aluminum sulfate and sodium hexametaphosphate, the regulator is preferably sodium carbonate, the fluorite activator is preferably an ammonia activator, and the fluorite collector is preferably a combination of fatty acids and sodium oleate; the mass ratio of the fatty acid to the sodium oleate is preferably (10-50): (50-90); the amount of the regulator is preferably 300-500 g / t; the amount of the inhibitor I is preferably 200-400 g / t; the amount of the fluorite activator is preferably 400-700 g / t; the amount of the fluorite collector is preferably 300-500 g / t;

[0040] Step 3, adding the slurry obtained in step 2 to a flotation machine to perform rough separation of fluorite to obtain flotation foam and rough separation tailings;

[0041] Step 4: Add inhibitor II to the flotation foam obtained in Step 3, perform the first fluorite selection to obtain fluorite concentrate I and medium ore I; inhibitor II is preferably modified water glass or / and carboxymethyl cellulose (same below); the amount of inhibitor II is preferably 50-200 g / t;

[0042] Step 5, adding inhibitor II to the fluorite concentrate I obtained in step 4, and performing a second fluorite concentration to obtain fluorite concentrate II and middlings II; the dosage of inhibitor II is preferably 50-150 g / t;

[0043] Step 6, adding inhibitor II to the fluorite concentrate II obtained in step 5, and performing a third fluorite concentration to obtain fluorite concentrate III and middlings III, wherein the fluorite concentrate III is the first fine-grained fluorite, i.e., the first fluorite concentrate product; the dosage of inhibitor II is preferably 10-100 g / t;

[0044] Step 7, the rougher tailings obtained in step 3, the middling II obtained in step 5 and the middling III obtained in step 6 are mixed and slurried to adjust the slurry concentration to 25%-30%, and then the adjusting agent, fluorite activator and inhibitor III are added, the adjusting agent is preferably sodium carbonate, the dosage is preferably 100-300g / t, the fluorite activator is preferably an ammonia activator, the dosage is preferably 100-300g / t, the inhibitor III is preferably a combination of inhibitor I in step 2 and inhibitor II in steps 4-6, the dosage is preferably 100-300g / t, the mass ratio of inhibitor I to inhibitor II is preferably (30-50): (50-70), and scavenging is performed to obtain sub-concentrate and scavenged tailings, the sub-concentrate is the second fine-grained fluorite, that is, the second fluorite concentrate product, the first fine-grained fluorite and the second fine-grained fluorite can be mixed and used or used independently. The middling 1 in step 4 and the scavenged tailings in step 7 are combined into the final tailings.

[0045] Note: The above steps are Figure 1 The meanings of the corresponding step contents are completely consistent, but the expressions are not necessarily exactly the same. This is to summarize the specific step contents of the present invention through concise drawings for easy intuitive understanding.

[0046] The present invention is described in more detail below with reference to two specific embodiments.

[0047] Embodiment 1:

[0048] The test ore sample is a magnetically separated rare earth tailings from a certain place in Sichuan, China. The rare earth tailings contain 70.13% fluorite (CaF2), 18.21% barite (BaSO4), 2.53% SiO2 and 5.82% CaCO3. First, the rare earth tailings are slurried to adjust the slurry concentration to 20%. After stirring for 10 minutes, a hydrocyclone is used to remove barite to obtain two products: sedimentation and overflow.

[0049] The concentration of the sedimentation product of the hydrocyclone is adjusted to 25%, and then, based on each ton of the raw ore, 400 g / t of sodium carbonate as an adjusting agent, 300 g / t of inhibitor I, where inhibitor I is one or more of water glass, sodium humate, sulfuric acid, aluminum sulfate and sodium hexametaphosphate, 550 g / t of fluorite activator, where an ammonia activator is selected, and 380 g / t of fluorite collector, where the fluorite collector is a combination of fatty acid and sodium oleate, are added in sequence, and fluorite flotation operation is performed to obtain flotation foam and roughing tailings;

[0050] The concentration of the flotation foam is adjusted to 25%, and then 150 g / t of inhibitor II is added per ton of raw ore, where the inhibitor II is modified water glass or / and carboxymethyl cellulose, to carry out the first fluorite concentration operation to obtain fluorite concentrate I and middlings I;

[0051] The concentration of fluorite concentrate I is adjusted to 30%, and then 100 g / t of inhibitor II is added per ton of raw ore, where the inhibitor II is modified water glass or / and carboxymethyl cellulose, and a second fluorite concentration operation is performed to obtain fluorite concentrate II and middlings II;

[0052] The concentration of fluorite concentrate II is adjusted to 30%, and then 50 g / t of inhibitor II is added per ton of raw ore, where the inhibitor II is modified water glass or / and carboxymethyl cellulose, and a third fluorite concentration operation is performed to obtain fluorite concentrate III and middlings III, wherein the fluorite concentrate III is the first fine-grained fluorite, i.e., the first fluorite concentrate product;

[0053] The mixed slurry concentration of the rougher tailings, middlings II and middlings III is adjusted to 25%, and then, based on each ton of the original ore, 200 g / t of adjusting agent sodium carbonate, 150 g / t of inhibitor III, which is a combination of inhibitor I and inhibitor II, and 200 g / t of fluorite activator, which is an ammonia activator, are added in sequence, and scavenging operations are carried out to obtain a second fine-grained fluorite, i.e., a second fluorite concentrate product and scavenged tailings.

[0054] The intermediate ore I and the scavenging tailings are combined into the final tailings.

[0055] Embodiment 2:

[0056] The test ore sample is a magnetically separated rare earth tailings from a certain place in Sichuan, China. The rare earth tailings contain 71.52% fluorite (CaF2), 12.21% barite (BaSO4), 2.31% SiO2 and 4.82% CaCO3. First, the rare earth tailings are slurried to adjust the slurry concentration to 20%. After stirring for 10 minutes, a hydrocyclone is used to remove barite to obtain two products: sedimentation and overflow.

[0057] The concentration of the sedimentation product of the hydrocyclone is adjusted to 25%, and then, based on each ton of the raw ore, 350 g / t of sodium carbonate as an adjusting agent, 280 g / t of inhibitor I, where inhibitor I is one or more of water glass, sodium humate, sulfuric acid, aluminum sulfate and sodium hexametaphosphate, 500 g / t of fluorite activator, which is an ammonia activator, and 400 g / t of fluorite collector, which is a combination of fatty acid and sodium oleate, are added in sequence, and fluorite flotation operation is performed to obtain flotation foam and roughing tailings;

[0058] The concentration of the flotation foam is adjusted to 25%, and then 100 g / t of inhibitor II is added per ton of raw ore, where the inhibitor II is modified water glass or / and carboxymethyl cellulose, to carry out the first fluorite concentration operation to obtain fluorite concentrate I and middlings I;

[0059] The concentration of fluorite concentrate I is adjusted to 30%, and then 75 g / t of inhibitor II is added per ton of raw ore, where the inhibitor II is modified water glass or / and carboxymethyl cellulose, and a second fluorite concentration operation is performed to obtain fluorite concentrate II and middlings II;

[0060] The concentration of fluorite concentrate II is adjusted to 30%, and then 40 g / t of inhibitor II is added per ton of raw ore, where the inhibitor II is modified water glass or / and carboxymethyl cellulose, and a third fluorite concentration operation is performed to obtain fluorite concentrate III and middlings III, wherein the fluorite concentrate III is the first fine-grained fluorite, i.e., the first fluorite concentrate product;

[0061] The mixed slurry concentration of the rougher tailings, middlings II and middlings III is adjusted to 25%, and then, per ton of original ore, 150 g / t of adjusting agent sodium carbonate, 150 g / t of inhibitor III, which is a combination of inhibitor I and inhibitor II, and 200 g / t of fluorite activator, which is an ammonia activator, are added in sequence, and scavenging operation is carried out to obtain the second fine-grained fluorite, i.e., the second fluorite concentrate product and scavenged tailings.

[0062] The intermediate ore I and the scavenging tailings are combined into the final tailings.

[0063] The main technical parameters of the products obtained in Example 1 and Example 2 are listed in the following table:

[0064]

[0065] The experimental results show that while improving the recovery rate and grade of fluorite, the method of the present invention effectively reduces the dosage of the agent, reduces the production cost, and significantly improves the production efficiency.

[0066] The above embodiments are only preferred embodiments of the present invention and are not limitations of the technical solutions of the present invention. Any technical solution that can be implemented on the basis of the above embodiments without creative work should be deemed to fall within the scope of protection of the patent of the present invention.

Claims

1. A method for separating and upgrading fine-grained fluorite in rare earth tailings, characterized in that: The following steps are involved: Step 1, slurrying the rare earth tailings in a mixing barrel, adjusting the slurry concentration to 20%, and obtaining two products of hydrocyclone sedimentation and overflow after barite removal pre-enrichment treatment by a hydrocyclone; Step 2, slurrying the sedimentation product obtained in step 1, adjusting the slurry concentration to 25%-30%, and adding a regulator, a fluorite activator, an inhibitor I and a fluorite collector to the slurry in sequence to obtain a treated slurry; Step 3, adding the slurry obtained in step 2 to a flotation machine to perform rough separation of fluorite to obtain flotation foam and rough separation tailings; Step 4, adding inhibitor II to the flotation foam obtained in step 3 to perform the first fluorite concentration to obtain fluorite concentrate I and middlings I; Step 5, adding inhibitor II to the fluorite concentrate I obtained in step 4, performing a second fluorite concentration, and obtaining fluorite concentrate II and middlings II; Step 6, adding inhibitor II to the fluorite concentrate II obtained in step 5, and performing a third fluorite concentration to obtain fluorite concentrate III and intermediate ore III, wherein the fluorite concentrate III is the first fine-grained fluorite; Step 7, the rougher tailings obtained in step 3, the middling ore II obtained in step 5 and the middling ore III obtained in step 6 are mixed and slurried to adjust the slurry concentration to 25%-30%, and then a regulator, a fluorite activator and an inhibitor III are added to perform scavenging to obtain a sub-concentrate and scavenged tailings, wherein the sub-concentrate is the second fine-grained fluorite, and the first fine-grained fluorite and the second fine-grained fluorite can be used in a mixed manner or independently.

2. The method for separating and upgrading fine-grained fluorite in rare earth tailings according to claim 1, characterized in that: In the step 1, the stirring frequency of the slurry adjustment is 50HZ, the stirring time is 10 minutes, the frequency of the slurry pump used to provide high-pressure slurry for the hydrocyclone is 40HZ, the feed pressure is 0.285Mpa, and the specification of the hydrocyclone is Φ20cm.

3. The method for separating and upgrading fine-grained fluorite in rare earth tailings according to claim 1, characterized in that: In step 2, inhibitor I is one or more of water glass, sodium humate, sulfuric acid, aluminum sulfate and sodium hexametaphosphate, the adjusting agent is sodium carbonate, the fluorite activator is an ammonia activator, and the fluorite collector is a combination of fatty acid and sodium oleate.

4. The method for separating and upgrading fine-grained fluorite in rare earth tailings according to claim 3, characterized in that: The mass ratio of the fatty acid to the sodium oleate is (10-50):(50-90).

5. The method for separating and upgrading fine-grained fluorite in rare earth tailings according to claim 3, characterized in that: In the step 2, the dosage of the adjusting agent is 300-500 g / t; the dosage of the inhibitor I is 200-400 g / t; the dosage of the fluorite activator is 400-700 g / t; and the dosage of the fluorite collector is 300-500 g / t.

6. The method for separating and upgrading fine-grained fluorite in rare earth tailings according to any one of claims 1 to 5, characterized in that: In the steps 4, 5 and 6, the inhibitor II is modified water glass and / or carboxymethyl cellulose.

7. The method for separating and upgrading fine-grained fluorite in rare earth tailings according to claim 6, characterized in that: The dosage of inhibitor II in step 4 is 50-200 g / t; the dosage of inhibitor II in step 5 is 50-150 g / t; the dosage of inhibitor II in step 6 is 10-100 g / t.

8. The method for separating and upgrading fine-grained fluorite in rare earth tailings according to any one of claims 1 to 5, characterized in that: In step 7, the adjusting agent is sodium carbonate, the fluorite activator is an ammonia activator, and the inhibitor III is a combination of the inhibitor I in step 2 and the inhibitor II in steps 4 to 6.

9. The method for separating and upgrading fine-grained fluorite in rare earth tailings according to claim 8, characterized in that: The mass ratio of inhibitor I to inhibitor II is (30-50):(50-70).

10. The method for separating and upgrading fine-grained fluorite in rare earth tailings according to claim 9, characterized in that: In step 7, the amount of the adjusting agent is 100-300 g / t, the amount of the inhibitor III is 100-300 g / t, and the amount of the fluorite activator is 100-300 g / t.

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