A method of fluorite flotation with calcite

Abstract

The application provides a method for fluorite flotation containing calcite, and belongs to the technical field of mineral flotation, and comprises the following steps: after grinding the fluorite crude ore containing calcite, the fluorite crude ore is mixed with water to obtain a first ore slurry; a hydroxyl carboxylic acid chelating agent is added to the first ore slurry to obtain a second ore slurry; an inhibitor is added to the second ore slurry to obtain a third ore slurry; a collector is added to the third ore slurry to obtain a fourth ore slurry; a frother is added to the fourth ore slurry for flotation to obtain fluorite concentrate. Based on the strong calcium ion chelation reaction, the hydroxyl carboxylic acid chelating agent and the calcium ions on the surface of calcite selectively form stable complexes, which not only enhances the hydrophilicity of the surface of calcite, but also generates a chemical bond with extremely high strength, so as to replace the fluorite precipitate on the surface of calcite, and achieve the purpose of cleaning the surface of calcite and eliminating the phenomenon of homogenous transformation.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of mineral flotation, in particular to a fluorite flotation method containing calcite. BACKGROUND

[0002] Fluorite (CaF2) is a non-renewable strategic non-metallic mineral resource, and its most important application field is chemical industry, and almost 50% of fluorite is used to produce hydrofluoric acid (HF) and other downstream products. Fluorite is often associated with calcite, and calcite can seriously affect the stability of the hydrofluoric acid production system and introduce carbon dioxide (CO2) impurities, causing safety hazards, reducing product quality, and reducing economic benefits, which is the most important impurity mineral affecting the production of acid. Therefore, it is crucial to remove calcite from fluorite, and it is a necessary condition for fluorite to produce high-quality hydrofluoric acid.

[0003] The flotation separation of fluorite and calcite is extremely challenging, and the fundamental reason is that the surface properties of the two are similar and can occur homogenous transformation. The homogenous transformation of fluorite and calcite is the process of generating fluorite particle precipitates on the surface of calcite and generating calcite on the surface of fluorite through dissolution and precipitation reactions, which makes the surface chemical composition and hydrophilic and hydrophobic properties of fluorite and calcite more similar, and seriously affects the selective adsorption of flotation reagents. Therefore, eliminating homogenous transformation is a prerequisite for realizing the deep removal of calcite in fluorite.

[0004] At present, the main method to remove the difficult-to-separate calcite impurities is to develop more effective calcite inhibitors. The most commonly used inhibitors include sodium silicate, modified sodium silicate, sodium hexametaphosphate, starch and humic acid sodium, etc. However, the development and application of these inhibitors are carried out on the premise that fluorite and calcite have not undergone homogenous transformation, and the influence of mineral surface precipitation on the effect of reagent and floatability is not considered, resulting in unsatisfactory effect of these inhibitors in practical application, and it is difficult to achieve the deep removal of trace calcite. The patent "Flotation method for improving the quality of metallurgical grade fluorite concentrate and reducing calcium content" (Patent No. CN118681680A) uses a one-stage roughing and four-stage cleaning flotation method to obtain a flotation concentrate with a grade of more than 90%. The method improves the quality of metallurgical grade fluorite concentrate by flotation, effectively realizes the purpose of improving the quality of metallurgical grade fluorite concentrate and reducing calcium content, but the flotation process is complex, the dosage of the depressant and modifier is about 1000 g / t, and the dosage of the collector is about 500 g / t. The patent "Flotation reagent for inhibiting calcite in fluorite-barite intergrowth ore" (Patent No. CN118341571A) uses 5-mononitrate isosorbide and water glass as the depressant, and sodium oleate and oxidized paraffin soap as the collector. Through one roughing, two cleaning and two scavenging, a fluorite concentrate with a grade of more than 95% is obtained under the condition of low reagent dosage. However, the main impurity in the fluorite ore used in the method is barite, and the content of calcite is low (only 15.13%), so the method is not suitable for fluorite ore with high calcite content. SUMMARY

[0005] In view of the technical problems in the background art, the present application provides a fluorite flotation method containing calcite, which aims to solve the following technical problems: ① it is difficult to separate fluorite and calcite by flotation, and it is difficult to obtain high-grade fluorite concentrate; ② the method process is long and complex, and requires complex method processes such as multi-stage cleaning and scavenging; ③ large amount of reagents are used, and the types of reagents are various, and a large amount of depressant is often used to inhibit calcite.

[0006] In a first aspect, the embodiments of the present application provide a fluorite flotation method containing calcite, which includes the following steps:

[0007] Grinding the fluorite rough ore containing calcite, and mixing it with water to obtain a first ore slurry;

[0008] Adjusting the temperature and pH of the first ore slurry, adding a hydroxycarboxylic acid chelating agent to it, stirring and reacting to obtain a second ore slurry;

[0009] Adding a depressant to the second ore slurry, stirring and reacting to obtain a third ore slurry;

[0010] Adding a collector to the third ore slurry, stirring and reacting to obtain a fourth ore slurry;

[0011] Flotation is performed on the fourth slurry by adding a frother to obtain a fluorite concentrate.

[0012] In some embodiments, the hydroxyl carboxylic acid chelating agent is added in an amount of 30-120 g / t; the hydroxyl carboxylic acid chelating agent is at least one of 4-hydroxybenzoic acid, dihydroxyethyl glycine, and sodium gluconate.

[0013] In some embodiments, the depressant is added in an amount of 50-200 g / t; the depressant is at least one of sodium silicate, modified sodium silicate, sodium hexametaphosphate, starch, and sodium humate.

[0014] In some embodiments, the collector is added in an amount of 100-250 g / t; the collector is at least one of sodium oleate, oxidized paraffin soap, sodium dodecyl sulfonate, and tall oil.

[0015] In some embodiments, the frother is added in an amount of 10-40 g / t.

[0016] In some embodiments, the fluorite crude ore containing calcite in the first slurry has a particle size of 38-150 μm, and the concentration of the first slurry is 15%-30%.

[0017] In some embodiments, the stirring reaction time is 2-10 min.

[0018] In some embodiments, the flotation comprises the following steps:

[0019] The frother is added to the fourth slurry for roughing, the roughing concentrate is subjected to three continuous cleanings, and the roughing tailings are subjected to one scavenging;

[0020] The cleaning concentrate is subjected to the next cleaning, the first cleaning tailings are returned to the roughing, the second and third cleaning tailings are returned to the previous cleaning, and the final flotation froth is a fluorite concentrate;

[0021] The scavenging concentrate is returned to the roughing, and the scavenging tailings are discharged.

[0022] In some embodiments, the depressant and the collector are supplemented during the second and third cleanings, the mass of the depressant supplemented during the second cleaning is 5%-15% of the mass of the depressant added during the roughing, the mass of the collector supplemented during the second cleaning is 10%-30% of the mass of the collector added during the roughing, the mass of the depressant supplemented during the third cleaning is 2%-10% of the mass of the depressant added during the roughing, and the mass of the collector supplemented during the third cleaning is 5%-15% of the mass of the collector added during the roughing.

[0023] In some embodiments, the stirring speed of the flotation is 800-1500 r / min.

[0024] In some embodiments, the air charge of the flotation is 0.1-0.4 m 3h, the flotation time is 5-15 min.

[0025] The beneficial effects of the present application, which are distinguished from the prior art solutions, include:

[0026] 1. The present application uses hydroxyl carboxylic acid chelating agent to synergistically inhibit calcite with high efficiency, and the type of reagent used is less, the cost is low, and the method process is simple and easy to control. Based on the strong calcium ion chelation reaction, the hydroxyl carboxylic acid chelating agent and the calcium ion on the surface of calcite selectively form a stable complex, which not only enhances the hydrophilicity of the calcite surface, but also generates a very high strength chemical bond, thereby replacing the fluorite precipitation on the surface of calcite, achieving the purpose of cleaning the surface of calcite and eliminating the phenomenon of homomorphism, and ultimately enhancing the inhibitory effect of the inhibitor on calcite. Under the condition of low reagent dosage, the flotation index of CaF2 grade 98.23% and recovery rate 96.45% can be realized through three-stage cleaning and one-stage scavenging.

[0027] 2. In the flotation method of the present application, first, the hydroxyl carboxylic acid chelating agent reacts with the calcium ion in calcite to form a complex, generating a very high strength chemical bond, thereby replacing the fluorite precipitation on the surface of calcite, achieving the purpose of cleaning the surface of calcite and eliminating the phenomenon of homomorphism, and ultimately enhancing the inhibitory effect of the inhibitor on calcite. Based on the above-mentioned hydroxyl carboxylic acid chelating agent, a method for eliminating the homomorphism of calcium carbonate associated fluorite is developed, which can efficiently promote the fluorite precipitation to fall off from the surface of calcite, expose the fresh surface of calcite and eliminate the influence of homomorphism, creating favorable conditions for the subsequent adsorption of inhibitors.

[0028] The above description is only a summary of the technical solutions of the present application, in order to more clearly understand the technical means of the present application, which can be implemented according to the content of the specification, and in order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the following specific embodiments of the present application will be described. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the present application, the following will briefly introduce the drawings used in the present application. Obviously, the drawings described below are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creating laborious work.

[0030] Figure 1 The flow chart of the fluorite flotation method in the present application.

[0031] Figure 2 The CaF2 grade and recovery rate test results of the fluorite concentrate prepared in Examples 1-5 and Comparative Examples 1-3.

[0032] Figure 3Figures 3 are SEM scanning diagrams of homogenized calcite before and after the action of sodium gluconate, wherein 3(a) is a SEM scanning diagram of homogenized calcite; and 3(b) is a SEM scanning diagram of homogenized calcite after the action of sodium gluconate. DETAILED DESCRIPTION

[0033] The embodiments of the technical solutions of the present application will be described in detail below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present application, and therefore only serve as examples, and cannot limit the protection scope of the present application.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the present application; the terms "include" and "have" and any variations thereof in the specification and claims of the present application and the above description of drawings are intended to cover non-exclusive inclusion.

[0035] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise explicitly and specifically limited.

[0036] Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the present application. The appearance of the phrase in various places in the specification does not necessarily all refer to the same embodiment, nor is it necessarily independent or alternative to other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0037] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of A alone, A and B together, and B alone. In addition, the character " / " in this paper generally represents that the front and rear associated objects are a "or" relationship.

[0038] In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two), and similarly, "multiple groups" refers to more than two groups (including two groups), and "multiple pieces" refers to more than two pieces (including two pieces).

[0039] At present, the main method to remove the difficult-to-separate calcite impurities is to develop calcite inhibitors with stronger inhibitory effect. The most commonly used inhibitors include sodium silicate, modified sodium silicate, sodium hexametaphosphate, starch and humic acid sodium, etc. However, the development and application of these inhibitors are carried out on the premise that fluorite and calcite have not undergone homogenous transformation, and the influence of mineral surface precipitation on the action of reagent and floatability is not considered, which leads to the fact that the effect of these inhibitors is not ideal in actual application, and it is difficult to achieve the deep removal of trace calcite.

[0040] In order to solve the technical problems of ① it is difficult to separate fluorite and calcite by flotation, and it is difficult to obtain high-grade fluorite concentrate; ② the method process is long and complex, and requires complex method processes such as multi-stage cleaning and scavenging; ③ large amount of reagents are used, and a large number of inhibitors are used to inhibit calcite, the application provides a fluorite flotation method containing calcite, wherein a hydroxyl carboxylic acid chelating agent is added to synergistically inhibit calcite with an inhibitor, and the types of reagents used are less, the cost is low, and the method process is simple and easy to control. Based on the strong calcium ion chelation reaction, the hydroxyl carboxylic acid chelating agent selectively forms a stable complex with the calcium ions on the surface of calcite, which not only enhances the hydrophilicity of the surface of calcite, but also generates a chemical bond with extremely high strength, thereby replacing the fluorite precipitation on the surface of calcite, achieving the purpose of cleaning the surface of calcite and eliminating the homogenous transformation phenomenon, and finally enhancing the inhibitory effect of the inhibitor on calcite. Under the condition of low reagent dosage, three-stage cleaning and one-stage scavenging can realize the flotation indexes of CaF2 grade 98.23% and recovery rate 96.45%.

[0041] In the first aspect, as shown in the formula (I), the embodiments of the application provide a fluorite flotation method containing calcite, which comprises the following steps: Figure 1 In the first aspect, as shown in the formula (I), the embodiments of the application provide a fluorite flotation method containing calcite, which comprises the following steps:

[0042] Grinding the fluorite crude ore containing calcite, and mixing with water to obtain a first ore slurry;

[0043] Adjusting the temperature and pH of the first ore slurry, adding a hydroxyl carboxylic acid chelating agent to the first ore slurry, stirring and reacting to obtain a second ore slurry;

[0044] Adding an inhibitor to the second ore slurry, stirring and reacting to obtain a third ore slurry;

[0045] Adding a collector to the third ore slurry, stirring and reacting to obtain a fourth ore slurry;

[0046] Adding a foaming agent to the fourth ore slurry for flotation to obtain fluorite concentrate.

[0047] In some embodiments, the amount of hydroxyl carboxylic acid chelating agent added is 30-120 g / t; the hydroxyl carboxylic acid chelating agent is at least one of 4-hydroxybenzoic acid, dihydroxyethyl glycine and sodium gluconate.

[0048] In some embodiments, the inhibitor is added in an amount of 50-200 g / t; the inhibitor is at least one of sodium silicate, modified sodium silicate, sodium hexametaphosphate, starch, and sodium humate.

[0049] In some embodiments, the collector is added in an amount of 100-250 g / t; the collector is at least one of sodium oleate, oxidized paraffin soap, sodium dodecyl sulfonate, and tall oil.

[0050] In some embodiments, the frother is added in an amount of 10-40 g / t.

[0051] In the technical solution of the embodiments of the present application, the hydroxyl carboxylic acid is an organic compound, which contains at least one hydroxyl or carboxyl group in the molecular structure. Since the hydroxyl and carboxyl groups have polarity, they can quickly form hydrogen bonds with water and become hydrophilic. In addition, the hydroxyl carboxylic acid is a calcium ion chelator, which has the ability to undergo strong chemical adsorption and complexation reaction with calcium ions on the surface of fluorite and calcite, forming a very stable chelate. This strong chemical adsorption can replace the chemical bonds between the fluorite or calcite precipitate and the mineral surface, thereby forming a hydrophilic chelate on the mineral surface, causing the mineral precipitate on the surface of fluorite and calcite to desorb, and ultimately eliminating the negative effects of polymorphic transformation.

[0052] In the present application, one or a combination of several typical hydroxyl carboxylic acid chelators, 4-hydroxybenzoic acid (C7H6O3), dihydroxyethyl glycine (C6H 13 NO4), and sodium gluconate (C6H 11 O7Na) are used as the synergistic inhibitor of calcite after polymorphic transformation. Due to the strong complexation of the hydroxyl carboxylic acid chelator with calcium ions on the mineral surface, the mineral precipitate on the surface of fluorite and calcite is removed, the adverse effects of polymorphic transformation on flotation separation are eliminated, and favorable conditions are created for the deep removal of calcite.

[0053] In some embodiments, the particle size of the fluorite crude ore containing calcite in the first ore slurry is 38-150 μm, and the concentration of the first ore slurry is 15%-30%.

[0054] In some embodiments, the temperature of the first ore slurry is 15-35°C, and the pH is 7-11.

[0055] In some embodiments, the stirring reaction time is 2-10 min.

[0056] In some embodiments, as shown in FIG. 1, the flotation includes the following steps: Figure 1 A frother is added to the fourth ore slurry for roughing, and the roughing concentrate is subjected to three times of continuous cleaning, and the roughing tailings are subjected to one time of scavenging.

[0057]

[0058] ​Each refined concentrate enters the next refined process. The tailings from the first refined process are returned to the roughing process, and the tailings from the second and third refined processes are returned to the previous refined process. The final flotation froth is fluorite concentrate.

[0059] The scavenging concentrate is returned to the roughing stage, and the scavenging tailings are discharged.

[0060] In the technical solution of this application embodiment, the carboxylic acid chelating agent is added to the first pulp before the inhibitor. It interacts with the fluorine-containing precipitate on the surface of calcite, removing the fluorite precipitate and eliminating its adverse effect on flotation. Then, the inhibitor is added, which enhances the inhibitor's inhibitory effect. This significantly reduces the dosage of the inhibitor (sodium silicate dosage in this application is 50-200 g / t) and shortens the flotation process (three cleaning stages and one scavenging stage in this application), thereby further improving the flotation effect and reducing costs.

[0061] In some embodiments, such as Figure 1 As shown, the amount of inhibitor added in the second purification stage (Purification II) is 5% to 15% of the amount of inhibitor added in the roughing stage; the amount of collector added in the second purification stage is 10% to 30% of the amount of collector added in the roughing stage; the amount of inhibitor added in the third purification stage (Purification III) is 2% to 10% of the amount of inhibitor added in the roughing stage; and the amount of collector added in the third purification stage is 5% to 15% of the amount of collector added in the roughing stage.

[0062] In some embodiments, the flotation stirring speed is 800~1500 r / min.

[0063] In some embodiments, the flotation aeration rate is 0.1~0.4 m³. 3 / h, flotation time is 5~15min.

[0064] The following are some specific embodiments. It should be noted that the embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0065] I. Preparation Method

[0066] The mineral sample used in this application embodiment is an artificial mixture of fluorite with a purity of 99.1% and calcite with a purity of 99.4% (each accounting for 50% by mass) to simulate the associated fluorite mineral containing a large amount of calcite.

[0067] Example 1

[0068] A flotation method for calcite-containing fluorite includes the following steps:

[0069] S1, the mineral sample mixed after fluorite, calcite with particle size of 38-150 μm and ultrapure water to prepare a slurry, the slurry concentration is 17%, the slurry pH is adjusted to 9 and the temperature is controlled at 25℃, 4-hydroxybenzoic acid 20 g / t, dihydroxyethyl glycine 20 g / t, sodium gluconate 20 g / t is added, and the reaction is carried out for 2 min, then the inhibitor sodium silicate 100 g / t is added, and the reaction is carried out for 2 min, then sodium oleate 200 g / t is added, and the reaction is carried out for 5 min.

[0070] S2, 20 g / t of methyl isobutyl carbinol is added to the slurry for roughing, and the roughing concentrate is subjected to three times of continuous cleaning, and the roughing tailings are subjected to one time of scavenging, the mass of sodium silicate added in the second and third cleaning is 10% and 5% of the mass of sodium silicate added in the roughing respectively, and the mass of the collector added in the second and third cleaning is 15% and 10% of the mass of the collector added in the roughing respectively.

[0071] The concentrate of each cleaning enters the next cleaning, the tailings of the first cleaning return to the roughing, the tailings of the second and third cleaning return to the previous cleaning, and finally the flotation froth is obtained as the fluorite concentrate;

[0072] The scavenging concentrate returns to the roughing, and the scavenging tailings are discharged.

[0073] The stirring speed is 1200 r / min, the aeration amount is 0.1 m 3 / h, the froth scraping time is 10 min, and the flotation froth obtained in the third cleaning is the fluorite concentrate.

[0074] The CaF2 grade of the obtained concentrate is 98.23%, and the recovery rate is 96.45%.

[0075] Example 2

[0076] A fluorite flotation method containing calcite, comprising the following steps:

[0077] S1, the mineral sample mixed after fluorite, calcite with particle size of 38-150 μm and ultrapure water to prepare a slurry, the slurry concentration is 15%, the slurry pH is adjusted to 11 and the temperature is controlled at 35℃, 4-hydroxybenzoic acid 40 g / t, dihydroxyethyl glycine 40 g / t, sodium gluconate 40 g / t is added, and the reaction is carried out for 10 min, then the inhibitor sodium silicate 200 g / t is added, and the reaction is carried out for 10 min, then sodium oleate 250 g / t is added, and the reaction is carried out for 10 min.

[0078] S2, 10 g / t of methyl isobutyl carbinol is added to the ore pulp for roughing, the roughing concentrate is subjected to three continuous cleanings, the roughing tailings are subjected to one scavenging, the mass of sodium silicate added in the second and third cleanings is 5% and 2% of the mass of sodium silicate added in the roughing respectively, and the mass of the collector added in the second and third cleanings is 10% and 5% of the mass of the collector added in the roughing respectively.

[0079] The concentrate of each cleaning is subjected to the next cleaning, the tailings of the first cleaning are returned to the roughing, the tailings of the second and third cleanings are returned to the previous cleaning, and the final flotation froth is fluorite concentrate;

[0080] The scavenging concentrate is returned to the roughing, and the scavenging tailings are discharged.

[0081] The stirring speed is 800 r / min, the aeration amount is 0.4 m 3 / h, the froth scraping time is 5 min, and the flotation froth obtained in the third cleaning is fluorite concentrate.

[0082] The CaF2 grade of the obtained concentrate is 98.76%, and the recovery rate is 93.46%.

[0083] Example 3

[0084] A fluorite flotation method containing calcite, comprising the following steps:

[0085] S1, the fluorite and calcite mixed mineral sample with a particle size of 38-150 μm is mixed with ultrapure water to prepare an ore pulp, the ore pulp concentration is 25%, the pH of the ore pulp is adjusted to 8 and the temperature is controlled at 15℃, 10 g / t of 4-hydroxybenzoic acid, 10 g / t of dihydroxyethyl glycine and 10 g / t of sodium gluconate are added, and reacted for 2 min, then 50 g / t of sodium silicate is added as an inhibitor, and reacted for 2 min, and then 100 g / t of sodium oleate is added, and reacted for 2 min.

[0086] S2, 40 g / t of methyl isobutyl carbinol is added to the ore pulp for roughing, the roughing concentrate is subjected to three continuous cleanings, the roughing tailings are subjected to one scavenging, the mass of sodium silicate added in the second and third cleanings is 15% and 10% of the mass of sodium silicate added in the roughing respectively, and the mass of the collector added in the second and third cleanings is 30% and 15% of the mass of the collector added in the roughing respectively.

[0087] The concentrate of each cleaning is subjected to the next cleaning, the tailings of the first cleaning are returned to the roughing, the tailings of the second and third cleanings are returned to the previous cleaning, and the final flotation froth is fluorite concentrate;

[0088] The scavenging concentrate is returned to the roughing, and the scavenging tailings are discharged.

[0089] The stirring speed is 1500 r / min, the aeration amount is 0.4 m 3 / h, the scraping time is 15 min, and the flotation froth obtained in the third cleaning is the fluorite concentrate.

[0090] The CaF2 grade of the obtained concentrate is 97.62%, and the recovery rate is 96.58%.

[0091] Example 4

[0092] A fluorite flotation method containing calcite, comprising the following steps:

[0093] S1, the mineral sample mixed by fluorite and calcite with a particle size of 38-150 μm is mixed with ultrapure water to obtain a slurry, the slurry concentration is 20%, the slurry pH is adjusted to 10 and the temperature is controlled at 30℃, 4-hydroxybenzoic acid 30 g / t, dihydroxyethyl glycine 30 g / t, sodium gluconate 30 g / t are added, and the reaction is carried out for 8 min, then the inhibitor sodium silicate 150 g / t is added, and the reaction is carried out for 8 min, then sodium oleate 200 g / t is added, and the reaction is carried out for 8 min.

[0094] S2, 15 g / t of methyl isobutyl carbinol is added to the slurry for roughing, the roughing concentrate is subjected to three times of continuous cleaning, and the roughing tailings are subjected to one time of scavenging, the mass of sodium silicate added in the second and third cleaning is 8% and 4% of the mass of sodium silicate added in the roughing respectively, and the mass of the collector added in the second and third cleaning is 15% and 8% of the mass of the collector added in the roughing respectively.

[0095] The concentrate of each cleaning enters the next cleaning, the tailings of the first cleaning return to the roughing, the tailings of the second and third cleaning return to the previous cleaning, and the final flotation froth is the fluorite concentrate;

[0096] The scavenging concentrate returns to the roughing, and the scavenging tailings are discharged.

[0097] The stirring speed is 1000 r / min, the aeration amount is 0.2 m 3 / h, the scraping time is 7 min, and the flotation froth obtained in the third cleaning is the fluorite concentrate.

[0098] The CaF2 grade of the obtained concentrate is 98.41%, and the recovery rate is 94.60%.

[0099] Example 5

[0100] A fluorite flotation method containing calcite, comprising the following steps:

[0101] S1, the mineral sample mixed with fluorite and calcite with particle size of 38-150 μm is mixed with ultrapure water to prepare a slurry, the concentration of the slurry is 20%, the pH of the slurry is adjusted to 8 and the temperature is controlled at 20℃, 4-hydroxybenzoic acid 15 g / t, dihydroxyethyl glycine 15 g / t, sodium gluconate 15 g / t are added, and the reaction is carried out for 4 min, then the inhibitor sodium silicate 80 g / t is added, and the reaction is carried out for 4 min, then sodium oleate 150 g / t is added, and the reaction is carried out for 4 min.

[0102] S2, 30 g / t of methyl isobutyl carbinol is added to the slurry for roughing, the roughing concentrate is subjected to three times of continuous cleaning, the roughing tailings are subjected to one time of scavenging, the mass of sodium silicate added in the second and third cleaning is 12% and 8% of the mass of sodium silicate added in the roughing respectively, and the mass of collector added in the second and third cleaning is 25% and 12% of the mass of collector added in the roughing respectively.

[0103] The concentrate of each cleaning is subjected to the next cleaning, the tailings of the first cleaning are returned to the roughing, the tailings of the second and third cleanings are returned to the previous cleaning, and finally the flotation froth is obtained as fluorite concentrate;

[0104] The scavenging concentrate is returned to the roughing, and the scavenging tailings are discharged.

[0105] The stirring speed is 1300 r / min, the aeration amount is 0.3 m 3 / h, the froth scraping time is 12 min, and the flotation froth obtained in the third cleaning is fluorite concentrate.

[0106] The CaF2 grade of the obtained concentrate is 97.83%, and the recovery rate is 96.23%.

[0107] Comparative Example 1

[0108] The difference between this comparative example and Example 1 is only that none of 4-hydroxybenzoic acid, dihydroxyethyl glycine, and sodium gluconate is added, and the CaF2 grade of the obtained concentrate is 89.53%, and the recovery rate is 97.99%.

[0109] Comparative Example 2

[0110] The difference between this comparative example and Example 1 is only that 100 g / t of 4-hydroxybenzoic acid, 100 g / t of dihydroxyethyl glycine, and 100 g / t of sodium gluconate are added, and the CaF2 grade of the obtained concentrate is 98.94%, and the recovery rate is 92.89%.

[0111] Comparative Example 3

[0112] The difference between this comparative example and Example 1 is only that no inhibitor sodium silicate is added, and the CaF2 grade of the obtained concentrate is 59.23%, and the recovery rate is 97.34%.

[0113] Comparative Example 4

[0114] Comparative Example 4 differs from Example 1 in that 4-hydroxybenzoic acid, dihydroxyethyl glycine, sodium gluconate and sodium silicate are simultaneously added to the ore slurry for reaction, comprising the following steps:

[0115] S1, the mineral sample mixed by fluorite and calcite with particle size of 38-150 μm is mixed with ultrapure water to prepare an ore slurry, the ore slurry concentration is 17%, the pH of the ore slurry is adjusted to 9 and the temperature is controlled at 25°C, 4-hydroxybenzoic acid 20 g / t, dihydroxyethyl glycine 20 g / t, sodium gluconate 20 g / t, and inhibitor sodium silicate 100 g / t are added, and the reaction is carried out for 2 min, and then sodium oleate 200 g / t is added, and the reaction is carried out for 5 min.

[0116] S2, 20 g / t of methyl isobutyl carbinol is added to the ore slurry for roughing, and the roughing concentrate is subjected to three times of continuous cleaning, and the roughing tailings are subjected to one time of scavenging, the mass of sodium silicate added in the second and third cleaning is 10% and 5% of the mass of sodium silicate added in the roughing respectively, and the mass of collector added in the second and third cleaning is 15% and 10% of the mass of collector added in the roughing respectively.

[0117] The concentrate of each cleaning is fed into the next cleaning, the tailings of the first cleaning are returned to the roughing, the tailings of the second and third cleanings are returned to the previous cleaning, and finally the flotation froth is obtained as the fluorite concentrate.

[0118] The scavenging concentrate is returned to the roughing, and the scavenging tailings are discharged.

[0119] The scavenging concentrate is returned to the first cleaning, the stirring speed is 1200 r / min, the aeration amount is 0.1 m 3 / h, the froth scraping time is 10 min, and the flotation froth obtained in the third cleaning is the fluorite concentrate.

[0120] The CaF2 grade of the obtained concentrate is 92.75%, and the recovery rate is 95.87%.

[0121] II. Test method

[0122] The detection method of the CaF2 grade of the concentrate is carried out according to the method specified in the Chinese national standard “GB / T 5195.1-2017 Fluorite Calcium Fluoride Content Determination EDTA Titration Method and Distillation-Potentiometric Titration Method”. The concentrate yield is determined by the percentage of the mass of the concentrate to the mass of the raw ore.

[0123] The recovery rate of CaF2 in the concentrate is determined by the following formula: recovery rate = (concentrate grade x yield / raw ore grade) x 100%.

[0124] III. Analysis of Test Results for Each Embodiment and Comparative Example

[0125] (1) The CaF2 grade and recovery rate of the concentrates obtained in Examples 1-5 and Comparative Examples 1-3 were tested, and the test results are shown in the figure. Figure 2 .from Figure 2 It can be seen that in Comparative Example 1, without the addition of hydroxycarboxylic acid chelating agents such as 4-hydroxybenzoic acid, dihydroxyethylglycine, and sodium gluconate, the grade of fluorite concentrate was low, only 89.53%. This indicates that without the addition of hydroxycarboxylic acid chelating agents, the reagent system using only 100 g / t sodium silicate and 200 g / t sodium oleate is insufficient to achieve efficient separation of fluorite and calcite. From Examples 1-5 and Comparative Example 2, it can be seen that when the dosage of hydroxycarboxylic acid chelating agents increases, the grade of fluorite concentrate does not improve significantly, while the recovery rate decreases to 92.89%. This indicates that excessive hydroxycarboxylic acid chelating agents inhibit fluorite flotation and adversely affect the separation of the two materials; therefore, the dosage of hydroxycarboxylic acid chelating agents should not be too high. As can be seen from Examples 1-5 and Comparative Example 3, without the addition of the inhibitor sodium silicate, the grade of fluorite concentrate was significantly reduced to 59.23%, indicating that hydroxycarboxylic acid chelating agents cannot be used alone as inhibitors, and their flotation inhibition effect on calcite is not strong.

[0126] Examples 1-5 and Comparative Example 4 show that when 4-hydroxybenzoic acid, dihydroxyethylglycine, sodium gluconate, and sodium silicate are added to the slurry simultaneously, the fluorite concentrate grade is low, at 92.75%. This indicates that mixing hydroxycarboxylic acid chelating agents with sodium silicate reduces their inhibitory effect. This is mainly because carboxylic acid chelating agents need to react with the fluorite-encapsulated layer on the calcite surface to remove it. If sodium silicate is added before the fluorite-encapsulated layer has completely detached, it cannot effectively adsorb onto the fluorite-encapsulated calcite surface, resulting in wasted reagents and reduced inhibitory effect.

[0127] (2) such as Figure 3 As shown, to more significantly demonstrate the exfoliation and activation effect of hydroxycarboxylic acid chelating agents on the homogenized calcite surface, SEM tests were performed on the homogenized calcite samples before and after sodium gluconate treatment to characterize the changes in their surface morphology. The results showed that spherical fluorite precipitates were observed on the surface of the homogenized calcite, resulting in calcite surfaces exhibiting properties similar to fluorite. However, after sodium gluconate treatment, the precipitates on the calcite surface were effectively removed, restoring the original surface characteristics of calcite, thereby enhancing the inhibitory effect of sodium silicate on calcite.

[0128] Using the method, fluorite and calcite can be effectively separated by flotation, the fluorite concentrate grade is as high as 98.23%, and the recovery rate is 96.45%. At the same time, the flotation process is effectively shortened, the reagent dosage is reduced, and the flotation cost is reduced. Compared with the traditional method, the removal rate of calcite is higher, and the flotation separation of fluorite and calcite is more thorough.

[0129] It should be noted that the present application is not limited to the above embodiments. The above embodiments are only examples, and embodiments having substantially the same configuration and playing the same role and effect as the technical idea within the scope of the technical solution of the present application are all included in the technical scope of the present application. In addition, within the scope of the main idea of the present application, various modifications that can be thought of by those skilled in the art are applied to the embodiments, and other ways constructed by combining part of the constituent elements in the embodiments are also included in the scope of the present application.

Claims

1. A method for the flotation of fluorite containing calcite, characterized in that, The method comprises the following steps: Grinding the coarse fluorite ore containing calcite, mixing with water to obtain a first ore slurry; Adjusting the temperature and pH of the first ore slurry, adding a hydroxyl carboxylic acid chelating agent, stirring and reacting to obtain a second ore slurry; the hydroxyl carboxylic acid chelating agent is at least one of 4-hydroxybenzoic acid, dihydroxyethyl glycine and sodium gluconate, and the addition amount is 30-120 g / t; Adding an inhibitor to the second ore slurry, stirring and reacting to obtain a third ore slurry; the inhibitor is at least one of sodium silicate, modified sodium silicate, sodium hexametaphosphate, starch and sodium humate, and the addition amount is 50-200 g / t; Adding a collector to the third ore slurry, stirring and reacting to obtain a fourth ore slurry; Flotation is performed on the fourth ore slurry by adding a frother to obtain fluorite concentrate.

2. The method according to claim 1, c h a r a c t e r i s e d in that The addition amount of the collector is 100-250 g / t; the collector is at least one of sodium oleate, oxidized paraffin soap, sodium dodecyl sulfonate and tall oil.

3. The method according to claim 1, c h a r a c t e r i z e d in that The addition amount of the frother is 10-40 g / t.

4. The method according to claim 1, c h a r a c t e r i z e d in that The particle size of the coarse fluorite ore containing calcite in the first ore slurry is 38-150 μm, and the concentration of the first ore slurry is 15%-30%.

5. The method according to claim 1, c h a r a c t e r i z e d in that The temperature of the first ore slurry is 15-35 ℃, and the pH is 7-11.

6. The method according to claim 1, c h a r a c t e r i z e d in that The flotation comprises the following steps: Adding a frother to the fourth ore slurry to perform roughing, performing three continuous cleanings on the roughing concentrate, and performing one scavenging on the roughing tailings; The concentrate of each cleaning enters the next cleaning, the tailings of the first cleaning returns to the roughing, the tailings of the second and third cleanings return to the previous cleaning, and the final flotation froth is fluorite concentrate; The scavenging concentrate returns to the roughing, and the scavenging tailings are discharged.

7. The method according to claim 6, c h a r a c t e r i z e d in that The inhibitor and the collector are supplemented during the second and third cleanings; the mass of the supplemented inhibitor during the second cleaning is 5%-15% of the mass of the inhibitor added during the roughing; the mass of the supplemented collector during the second cleaning is 10%-30% of the mass of the collector added during the roughing; the mass of the supplemented inhibitor during the third cleaning is 2%-10% of the mass of the inhibitor added during the roughing; and the mass of the supplemented collector during the third cleaning is 5%-15% of the mass of the collector added during the roughing.

8. The method according to claim 1, c h a r a c t e r i z e d in that The flotation stirring speed is 800-1500 r / min; the flotation air supply is 0.1-0.4 m 3 / h, and the flotation time is 5-15 min.

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