Reverse flotation combination inhibitors, reverse flotation method of spodumene in lithium-containing phosphate ores

Abstract

The application provides a reverse flotation combined inhibitor and a reverse flotation method of spodumene in phosphorus-containing lithium ore, and particularly relates to the technical field of ore dressing. The reverse flotation combined inhibitor is used for separating spodumene and amblygonite in the phosphorus-containing lithium ore; the reverse flotation combined inhibitor comprises polyacrylic acid and its salt, alginate, sulfate, sodium hexametaphosphate and sodium humate. The components form a multi-level synergistic inhibition mechanism of "adsorption-bridging-coverage-stability" on a molecular scale, significantly enhance the inhibition intensity and selectivity of spodumene, and basically do not produce inhibition to amblygonite, so as to ensure that the amblygonite can be effectively collected by a fatty acid collector and enter a froth product in the reverse flotation, and finally realize that the P2O5 content of the spodumene concentrate is stable and less than or equal to 0.98%, the phosphorus removal rate is greater than or equal to 86.3%, the loss rate of lithium in the amblygonite tailings is controlled to be less than or equal to 21.8%, the subsequent smelting impurity removal load is greatly reduced, and the comprehensive recovery rate of lithium resources and the economic value of the concentrate are improved.

Description

Technical Field

[0001] This invention relates to the field of mineral processing technology, and in particular to a reverse flotation combination inhibitor and a reverse flotation method for spodumene in lithium phosphate ores. Background Technology

[0002] Spodumene is currently the most important strategic raw material for industrial lithium extraction, and its efficient enrichment relies on flotation processes. In actual production, especially for typical low-grade lithium phosphate ores, spodumene often coexists with lithium aluminum phosphate (LiAl3(PO4)2(OH)4), a phosphorus-containing mineral with similar structure and surface properties. Both belong to layered silicates and contain Li in their crystal lattices. + Al 3+ The presence of hydroxyl groups makes effective dissociation difficult in conventional direct flotation, resulting in a large amount of phosphite (Lithium Aluminum Phosphate) being mixed in with spodumene concentrate, causing severe P2O5 contamination. According to non-ferrous metal industry standards, the P2O5 content in all spodumene concentrate products must be controlled below 1.0%, requiring a dephosphorization process to be added at or after the flotation stage. Current mainstream solutions mostly adopt a technical route of suppressing phosphite (Lithium Aluminum Phosphate) in the reverse flotation of spodumene. The key lies in developing a spodumene-specific depressant with high selectivity and strong inhibition.

[0003] However, traditional inhibitors have significant limitations: while sodium sulfide is widely used, it is easily oxidized and deactivated, its inhibitory effect is irreversible, and it also has a weak inhibitory effect on spodumene. This leads to a simultaneous decrease in spodumene recovery and inhibition of spodumene flotation, resulting in poor separation selectivity. Although single organic polymers or inorganic phosphates have a certain adsorption selectivity, they lack multiple mechanisms for synergistically regulating the surface charge, hydration film thickness, and calcium / iron ion bridging ability of minerals. This makes it difficult to achieve a stable and precise decoupling between strong passivation of the spodumene surface and retention of active sites on the spodumene surface in complex ionic environments. In particular, when the P2O5 content of the raw ore exceeds 5.0 wt%, the P2O5 residue in the spodumene concentrate is generally higher than 2.5 wt% under conventional reagent systems. The lithium loss rate in the spodumene tailings exceeds 30%, which not only fails to meet the standards for sale but also significantly increases the acid consumption and slag volume in subsequent smelting and dephosphorization, thus restricting the green and efficient utilization of lithium resources. Therefore, there is an urgent need for a novel combination inhibitor with clearly defined components, complementary mechanisms, broad pH adaptability, and both strong inhibitory properties and high selectivity, in order to overcome the technical bottleneck of accurate inhibition, clean flotation, and minimal loss in the spodumene-phosphorus aluminum phosphate system.

[0004] In view of this, the present invention is hereby proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a reverse flotation combination inhibitor and a reverse flotation method for spodumene in lithium phosphate ores, aiming to solve at least one of the above-mentioned technical problems in the prior art.

[0006] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted:

[0007] A first aspect of the present invention provides a reverse flotation combination inhibitor for separating spodumene and phosphogypsum from lithium phosphate ores; the reverse flotation combination inhibitor comprises polyacrylic acid and its salts, alginate, sulfate, sodium hexametaphosphate and sodium humate.

[0008] Furthermore, the anti-flotation combination inhibitor, by weight, comprises 40-70 parts of polyacrylic acid and its salts, 10-40 parts of alginate, 10-30 parts of sulfate, 5-20 parts of sodium hexametaphosphate, and 5-15 parts of sodium humate.

[0009] Preferably, the reverse flotation combination inhibitor comprises, by weight, 45-70 parts of polyacrylic acid and its salts, 10-35 parts of alginate, 10-25 parts of sulfate, 5-15 parts of sodium hexametaphosphate, and 5-10 parts of sodium humate.

[0010] Furthermore, the polyacrylic acid and its salts include polyacrylic acid and / or sodium polyacrylate.

[0011] Preferably, the polyacrylic acid and its salt are sodium polyacrylate.

[0012] Preferably, the molecular weight of the sodium polyacrylate is 1000-5000.

[0013] Furthermore, the alginate includes sodium alginate and / or potassium alginate.

[0014] Preferably, the sulfate includes at least one of aluminum sulfate, ferric sulfate, ferrous sulfate, and potassium aluminum sulfate.

[0015] The second aspect of the present invention provides a reverse flotation method for spodumene in lithium phosphate ore, wherein the reverse flotation combination inhibitor is used to suppress spodumene in the lithium phosphate ore and reverse flotation of lithium phosphate aluminum ore to obtain spodumene concentrate and lithium phosphate aluminum ore tailings.

[0016] Furthermore, the amount of the reverse flotation combination inhibitor is ≥500g / t.

[0017] Preferably, the amount of the reverse flotation combination inhibitor is 500~2000g / t, more preferably 600~1500g / t.

[0018] Furthermore, the reagents used in the reverse flotation also include a collector.

[0019] Preferably, the collector includes at least one of oleic acid, sodium oleate, tal oil, and oxidized paraffin soap.

[0020] Preferably, the amount of the collector is 100~1000g / t.

[0021] Furthermore, the phosphorus-bearing lithium ore is mainly obtained from lithium ore through positive flotation.

[0022] Preferably, the reagents used in the positive flotation include metal ion activators and fatty acid collectors.

[0023] Furthermore, the metal ion activator includes at least one of calcium chloride, magnesium chloride, and ferric chloride.

[0024] Furthermore, the fatty acid collector includes at least one of sodium oleate, oxidized paraffin soap, and naphthenic acid soap.

[0025] Compared with the prior art, the present invention has at least the following beneficial effects:

[0026] The anti-flotation combined inhibitor provided by this invention comprises polyacrylic acid and its salts, which provide strong anion adsorption capacity and steric hindrance effect, preferentially chelating Ca on the surface of spodumene. 2+ / Mg 2+ Active sites and form a dense hydration-inhibiting film; alginate enhances the specific hydrogen bonding and electrostatic shielding of spodumene crystal faces (especially (100) and (010) faces) with its abundant carboxyl and hydroxyl groups; sulfate, through Fe 3+ / Al 3+ Hydrolysis products form a slightly soluble hydroxide precipitate layer on the surface of spodumene, further enhancing physical coverage. Sodium hexametaphosphate plays a dual role of dispersion and stabilization, both inhibiting sludge covering and regulating the colloidal stability of the system. Sodium humate enhances the overall reagent's interfacial adaptability and anti-interference ability in complex ionic environments through directional adsorption of hydrophobic groups and π–π interactions. At the molecular scale, the components form a multi-level synergistic inhibition mechanism of "adsorption-bridging-coverage-stabilization," significantly enhancing the inhibition intensity and selectivity for spodumene, while exhibiting minimal inhibition of phosphite with similar structures but higher surface zeta potential and lower hydroxyl density. This ensures that phosphite can be effectively collected by fatty acid collectors in reverse flotation and enter the foam product, ultimately achieving a stable P2O5 content of ≤0.98% and a phosphorus removal rate of ≥86.3% in the spodumene concentrate, while controlling the lithium loss rate in the phosphite tailings to ≤21.8%, significantly reducing the subsequent smelting and impurity removal load, and improving the comprehensive recovery rate of lithium resources and the economic value of the concentrate.

[0027] The reverse flotation method provided by this invention utilizes the selective and efficient inhibition of spodumene and the low interference with lithium phosphate aluminum ore by the above-mentioned combined inhibitors. Under conventional flotation conditions (pH 4-10, inhibitor ≥500 g / t, combined with fatty acid collectors), it achieves highly selective separation of spodumene and lithium phosphate aluminum ore, which is significantly better than traditional methods such as sodium sulfide. Moreover, this reverse flotation method has mild process conditions, environmentally friendly reagents, and does not require strong acids or complex control, and can be directly adapted to existing production lines, effectively reducing the cost of subsequent smelting and impurity removal, and improving the efficiency and economy of lithium resource recovery. Attached Figure Description

[0028] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0029] Figure 1 A mineral processing method roadmap provided for Test Example 1. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0031] In the following, the terms “comprising,” “having,” and their cognates, which may be used in various embodiments of the invention, are intended only to indicate a particular feature, number, step, operation, element, component, or combination thereof, and should not be construed as excluding, firstly, the presence of one or more other features, numbers, steps, operations, elements, components, or combinations thereof, or adding the possibility of one or more features, numbers, steps, operations, elements, components, or combinations thereof.

[0032] A first aspect of the present invention provides a reverse flotation combination inhibitor for separating spodumene and phosphogypsum from lithium phosphate ores; the reverse flotation combination inhibitor comprises polyacrylic acid and its salts, alginate, sulfate, sodium hexametaphosphate and sodium humate.

[0033] The anti-flotation combined inhibitor provided by this invention comprises polyacrylic acid and its salts, which provide strong anion adsorption capacity and steric hindrance effect, preferentially chelating Ca on the surface of spodumene. 2+ / Mg 2+Active sites and form a dense hydration-inhibiting film; alginate enhances the specific hydrogen bonding and electrostatic shielding of spodumene crystal faces (especially (100) and (010) faces) with its abundant carboxyl and hydroxyl groups; sulfate, through Fe 3+ / Al 3+ Hydrolysis products form a slightly soluble hydroxide precipitate layer on the surface of spodumene, further enhancing physical coverage. Sodium hexametaphosphate plays a dual role of dispersion and stabilization, both inhibiting sludge covering and regulating the colloidal stability of the system. Sodium humate enhances the overall reagent's interfacial adaptability and anti-interference ability in complex ionic environments through directional adsorption of hydrophobic groups and π–π interactions. At the molecular scale, the components form a multi-level synergistic inhibition mechanism of "adsorption-bridging-coverage-stabilization," significantly enhancing the inhibition intensity and selectivity for spodumene, while exhibiting minimal inhibition of phosphite with similar structures but higher surface zeta potential and lower hydroxyl density. This ensures that phosphite can be effectively collected by fatty acid collectors in reverse flotation and enter the foam product, ultimately achieving a stable P2O5 content of ≤0.98% and a phosphorus removal rate of ≥86.3% in the spodumene concentrate, while controlling the lithium loss rate in the phosphite tailings to ≤21.8%, significantly reducing the subsequent smelting and impurity removal load, and improving the comprehensive recovery rate of lithium resources and the economic value of the concentrate.

[0034] Furthermore, the anti-flotation combination inhibitor, by weight, comprises 40-70 parts of polyacrylic acid and its salts, 10-40 parts of alginate, 10-30 parts of sulfate, 5-20 parts of sodium hexametaphosphate, and 5-15 parts of sodium humate.

[0035] Preferably, the reverse flotation combination inhibitor comprises, by weight, 45-70 parts of polyacrylic acid and its salts, 10-35 parts of alginate, 10-25 parts of sulfate, 5-15 parts of sodium hexametaphosphate, and 5-10 parts of sodium humate.

[0036] Typical, but not limiting, the anti-flotation combination inhibitors, by weight, may be 40, 45, 50, 55, 60, 65, or 70 parts of polyacrylic acid and its salts, or any value within the range of 40 to 70 parts; alginate may be 10, 15, 20, 25, 30, 35, or 40 parts, or any value within the range of 10 to 40 parts; sulfate may be 10, 15, 20, 25, or 30 parts, or any value within the range of 10 to 30 parts; sodium hexametaphosphate may be 5, 10, 15, or 20 parts, or any value within the range of 5 to 20 parts; sodium humate may be 5, 8, 10, 12, or 15 parts, or any value within the range of 5 to 15 parts.

[0037] In some preferred embodiments of the present invention, the reverse flotation combination inhibitor, by weight parts, may be, for example, 45 parts, 50 parts, 55 parts, 60 parts, 65 parts, or 70 parts, or any value within the range of 45 to 70 parts; alginate may be, for example, 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, or 35 parts, or any value within the range of 10 to 35 parts; sulfate may be, for example, 10 parts, 15 parts, 20 parts, or 25 parts, or any value within the range of 10 to 25 parts; sodium hexametaphosphate may be, for example, 5 parts, 8 parts, 10 parts, 12 parts, or 15 parts, or any value within the range of 5 to 15 parts; sodium humate may be, for example, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, or 10 parts, or any value within the range of 5 to 10 parts.

[0038] Furthermore, the polyacrylic acid and its salts include polyacrylic acid and / or sodium polyacrylate.

[0039] Preferably, the polyacrylic acid and its salt are sodium polyacrylate.

[0040] Preferably, the sodium polyacrylate has a molecular weight of 1000-5000. When the molecular weight is <1000, the chain length is insufficient, resulting in steric hindrance and limited hydration film thickness, making it difficult to form a dense and stable surface coating. This leads to insufficient inhibition of spodumene and susceptibility to precipitation or deactivation due to interference from polyvalent ions in the slurry. When the molecular weight is >5000, excessive entanglement, decreased solubility, and sluggish diffusion kinetics can easily occur, reducing not only its dispersion uniformity and interfacial adsorption rate in the slurry but also potentially inhibiting lithium aluminum phosphate due to enhanced nonspecific bridging, thus impairing selectivity. Sodium polyacrylate in the 1000-5000 range combines good water solubility, fast surface migration ability, moderate chelation coordination density (containing sufficient free carboxyl groups), and excellent steric shielding ability, enabling it to efficiently chelate Ca on the spodumene surface. 2+ / Mg 2+ The active site can also work with other components to construct a multi-level inhibition membrane with distinct layers, significantly improving inhibition strength, selectivity and stability against ion interference.

[0041] Typically, but not limitingly, the molecular weight of the sodium polyacrylate can be, for example, 1000, 2000, 3000, 4000 or 5000, or any value in the range of 1000 to 5000.

[0042] Furthermore, the alginate includes sodium alginate and / or potassium alginate.

[0043] Preferably, the sulfate includes at least one of aluminum sulfate, ferric sulfate, ferrous sulfate, and potassium aluminum sulfate.

[0044] The second aspect of the present invention provides a reverse flotation method for spodumene in lithium phosphate ore, wherein the reverse flotation combination inhibitor is used to suppress spodumene in the lithium phosphate ore and reverse flotation of lithium phosphate aluminum ore to obtain spodumene concentrate and lithium phosphate aluminum ore tailings.

[0045] The reverse flotation method provided by this invention utilizes the selective and efficient inhibition of spodumene and the low interference with lithium phosphate aluminum ore by the above-mentioned combined inhibitors. Under conventional flotation conditions (pH 4-10, inhibitor ≥500 g / t, combined with fatty acid collectors), it achieves highly selective separation of spodumene and lithium phosphate aluminum ore, which is significantly better than traditional methods such as sodium sulfide. Moreover, this reverse flotation method has mild process conditions, environmentally friendly reagents, and does not require strong acids or complex control, and can be directly adapted to existing production lines, effectively reducing the cost of subsequent smelting and impurity removal, and improving the efficiency and economy of lithium resource recovery.

[0046] Furthermore, the amount of the reverse flotation combination inhibitor is ≥500g / t.

[0047] Preferably, the amount of the reverse flotation combination inhibitor is 500~2000g / t, more preferably 600~1500g / t.

[0048] Typically, but not limitingly, the dosage of the reverse flotation combination inhibitor can be, for example, 500 g / t, 600 g / t, 800 g / t, 1000 g / t, 1200 g / t, 1500 g / t, 1800 g / t, or 2000 g / t, or any value within the range of 500 to 2000 g / t; preferably, the dosage of the reverse flotation combination inhibitor can be, for example, 600 g / t, 700 g / t, 900 g / t, 1000 g / t, 1200 g / t, or 1500 g / t, or any value within the range of 600 to 1500 g / t.

[0049] Preferably, during the reverse flotation process, the pH of the slurry is 4-10, more preferably 5-9, and even more preferably 6-7.

[0050] Typically, but not limitingly, in the reverse flotation process, the pH of the pulp can be, for example, 4, 5, 6, 7, 8, 9 or 10, or any value in the range of 4 to 10; preferably, the pH of the pulp can be, for example, 5, 6, 7, 8 or 9, or any value in the range of 5 to 9; more preferably, the pH of the pulp can be, for example, 6 or 7, or any value in the range of 6 to 7.

[0051] Furthermore, the reagents used in the reverse flotation also include a collector.

[0052] Preferably, the collector includes at least one of oleic acid, sodium oleate, tal oil, and oxidized paraffin soap.

[0053] Preferably, the amount of the collector is 100~1000g / t.

[0054] Typically, but not limitingly, the amount of the collector can be, for example, 100 g / t, 200 g / t, 400 g / t, 600 g / t, 800 g / t or 1000 g / t, or any value in the range of 100 to 1000 g / t.

[0055] Furthermore, the phosphorus-bearing lithium ore is mainly obtained from lithium ore through positive flotation.

[0056] Preferably, the reagents used in the positive flotation include metal ion activators and fatty acid collectors.

[0057] Furthermore, the metal ion activator includes at least one of calcium chloride, magnesium chloride, and ferric chloride.

[0058] Furthermore, the fatty acid collector includes at least one of sodium oleate, oxidized paraffin soap, and naphthenic acid soap.

[0059] The present invention is further illustrated below with specific embodiments and comparative examples. However, it should be understood that these embodiments are merely for illustrative purposes and should not be construed as limiting the invention in any way. Unless otherwise specified, the raw materials used in the embodiments and comparative examples of the present invention were carried out under conventional conditions or conditions recommended by the manufacturer. Reagents or instruments used, unless otherwise specified, are all commercially available conventional products.

[0060] The effects of this invention are illustrated using high-phosphorus lithium concentrate obtained from flotation in Sichuan Province as an example. Unless otherwise stated, the mineral compositions used in the following examples and comparative examples are shown in Table 1:

[0061] Table 1. Original Grade and Origin of High Phosphorus and Lithium Concentrate

[0062]

[0063] Example 1

[0064] This embodiment provides a reverse flotation combined inhibitor, the components of which are sodium polyacrylate (molecular weight 2000): sodium alginate: ferrous sulfate: sodium hexametaphosphate: sodium humate = 5:2:1.4:1:0.6 (by weight).

[0065] Example 2

[0066] This embodiment provides an anti-flotation combined inhibitor, the components of which are sodium polyacrylate (molecular weight 2000): sodium alginate: ferrous sulfate: sodium hexametaphosphate: sodium humate = 6.5:1:1:0.9:0.6 (by weight).

[0067] Example 3

[0068] This embodiment provides a reverse flotation combined inhibitor, the components of which are sodium polyacrylate (molecular weight 2000): sodium alginate: ferrous sulfate: sodium hexametaphosphate: sodium humate = 4:2.5:2:0.9:0.6 (by weight).

[0069] Example 4

[0070] This embodiment provides a reverse flotation combined inhibitor, the components of which are sodium polyacrylate (molecular weight 2000): potassium alginate: ferrous sulfate: sodium hexametaphosphate: sodium humate = 5:2:1.4:1:0.6 (by weight).

[0071] Example 5

[0072] This embodiment provides a reverse flotation combined inhibitor, the components of which are sodium polyacrylate (molecular weight 2000): sodium alginate: ferric sulfate: sodium hexametaphosphate: sodium humate = 5:2:1.4:1:0.6 (by weight).

[0073] Example 6

[0074] This embodiment provides a reverse flotation combined inhibitor, the components of which are sodium polyacrylate (molecular weight 2000): sodium alginate: aluminum sulfate: sodium hexametaphosphate: sodium humate = 5:2:1.4:1:0.6 (by weight).

[0075] Example 7

[0076] This embodiment provides an anti-flotation combined inhibitor, the components of which are sodium polyacrylate (molecular weight 2000): alginate: potassium aluminum sulfate: sodium hexametaphosphate: sodium humate = 5:2:1.4:1:0.6 (by weight).

[0077] Example 8

[0078] This embodiment provides a reverse flotation combined inhibitor. Unlike Example 1, the molecular weight of sodium polyacrylate is 800. The other components and dosages are the same as in Example 1, and will not be repeated here.

[0079] Example 9

[0080] This embodiment provides a reverse flotation combined inhibitor. Unlike Example 1, the molecular weight of sodium polyacrylate is 1000. The other components and dosages are the same as in Example 1, and will not be repeated here.

[0081] Example 10

[0082] This embodiment provides a reverse flotation combined inhibitor. Unlike Example 1, the molecular weight of sodium polyacrylate is 5000. The other components and dosages are the same as in Example 1, and will not be repeated here.

[0083] Example 11

[0084] This embodiment provides a reverse flotation combined inhibitor. Unlike Example 1, the molecular weight of sodium polyacrylate is 6000. The other components and dosages are the same as in Example 1, and will not be repeated here.

[0085] Comparative Example 1

[0086] This comparative example provides an inhibitor, specifically sodium sulfide.

[0087] Comparative Example 2

[0088] This comparative example provides an inhibitor, specifically sodium polyacrylate.

[0089] Comparative Example 3

[0090] This comparative example provides an inhibitor, specifically sodium alginate.

[0091] Comparative Example 4

[0092] This comparative example provides an inhibitor, specifically potassium alginate.

[0093] Comparative Example 5

[0094] This comparative example provides an inhibitor, specifically ferric sulfate.

[0095] Comparative Example 6

[0096] This comparative example provides an inhibitor, specifically ferrous sulfate.

[0097] Comparative Example 7

[0098] This comparative example provides an inhibitor, specifically sodium hexametaphosphate.

[0099] Comparative Example 8

[0100] This comparative example provides an inhibitor, specifically sodium humate.

[0101] Comparative Example 9

[0102] This comparative example provides an inhibitor with the following composition: sodium polyacrylate: sodium alginate: ferrous sulfate = 3:1:1 (by weight).

[0103] Comparative Example 10

[0104] This comparative example provides an inhibitor with the following composition: sodium polyacrylate: sodium alginate: sodium hexametaphosphate = 3:1:1 (by weight).

[0105] Comparative Example 11

[0106] This comparative example provides an inhibitor with the following composition: sodium polyacrylate: sodium alginate: sodium humate = 3:1:1 (by weight).

[0107] Comparative Example 12

[0108] This comparative example provides a reverse flotation combined inhibitor with the following composition: sodium alginate: ferrous sulfate: sodium hexametaphosphate: sodium humate = 2:1.4:1:0.6 (by weight).

[0109] Comparative Example 13

[0110] This comparative example provides a reverse flotation combined inhibitor with the following composition: sodium polyacrylate: ferrous sulfate: sodium hexametaphosphate: sodium humate = 5:1.4:1:0.6 (by weight).

[0111] Comparative Example 14

[0112] This comparative example provides a reverse flotation combined inhibitor with the following composition: sodium polyacrylate: sodium alginate: sodium hexametaphosphate: sodium humate = 5:2:1:0.6 (by weight).

[0113] Comparative Example 15

[0114] This comparative example provides a reverse flotation combined inhibitor with the following composition: sodium polyacrylate: sodium alginate: ferrous sulfate: sodium humate = 5:2:1.4:0.6 (by weight).

[0115] Comparative Example 16

[0116] This comparative example provides a reverse flotation combined inhibitor with the following composition: sodium polyacrylate: sodium alginate: ferrous sulfate: sodium hexametaphosphate = 5:2:1.4:1 (by weight).

[0117] Test Example 1

[0118] The inhibitors obtained from the examples and comparative examples were used in mineral processing.

[0119] The specific operation is as follows: lithium ore a is added to the flotation cell, and the pulp concentration is 30% after slurry conditioning.

[0120] use Figure 1 The process shown employs a roughing-cleansing-scavenging process for reverse flotation of lithium ore a, with the pulp temperature at room temperature.

[0121] During roughing, first add an appropriate amount of dilute sulfuric acid to adjust the pH of the pulp to 7 and stir for 3 minutes; then add 800 g / t of the inhibitor provided in the examples or comparative examples and stir for 3 minutes; then add 400 g / t of the collector sodium oleate and stir for 3 minutes; finally, aerate and skim the bubbles for 3 minutes.

[0122] For the scavenging process, 400 g / t of inhibitor and 200 g / t of collector sodium oleate, provided in the examples or comparative examples with half the dosage, are added sequentially, and the stirring time is 3 min, 3 min, and the foaming time is 3 min.

[0123] For the selected method, only 400g / t of the inhibitor provided in the example or comparative example with half the dosage is added and stirred for 2 minutes, followed by skimming for 3 minutes.

[0124] The middlings are returned sequentially for closed-loop circulation. After reaching equilibrium, the phosphate-lithium-aluminum tailings are scraped out with the foam into the tailings basin, while the spodumene concentrate remains in the flotation cell. The concentrate and tailings are filtered, dried, weighed, sampled, and tested to obtain the P2O5 and Li2O grades and calculate the recovery rate. The data are recorded in Tables 2 and 3.

[0125] The separation effect statistics are based on changes under roughing conditions, with the reverse flotation pulp pH at 7; the inhibitor dosage at 800 g / t; and the collector sodium oleate dosage at 400 g / t.

[0126] Table 2

[0127]

[0128]

[0129] Table 3

[0130]

[0131]

[0132] As can be seen from Tables 2 and 3, under the roughing conditions, Examples 1-7 all achieved P2O5 ≤ 0.98% in spodumene concentrate, with phosphorus removal rate stable in the range of 85.56%-86.45%, and lithium loss rate in phosphate-bauxite tailings controlled between 18.45%-21.79%, which are all superior to the industry standards and comparative examples.

[0133] Example 1 showed the best performance, with P2O5 reduced to 0.92%, dephosphorization rate reaching 86.31%, lithium tailings loss rate as low as 18.45%, and spodumene recovery rate as high as 81.55%, confirming that its formulation achieved the best balance between inhibition strength, selectivity, and resource recovery efficiency. In contrast, although Example 2 maintained a five-element structure, the imbalance in the alginate ratio led to an increase in P2O5 to 0.98% and a lithium loss rate of 21.27%, confirming that each component can trigger a molecular-scale adsorption-bridging-coverage-stabilization cascade effect within a specific weight window, and that even small perturbations in the ratio weaken the synergistic boundary.

[0134] Comparative Example 1, a commonly used industrial inhibitor, had a concentrate P2O5 content as high as 3.74%, a dephosphorization rate of only 39.12%, and a lithium loss rate soaring to 44.14%, highlighting the non-selective inhibition defects of traditional agents on lithium phosphate aluminum ore. While Comparative Examples 2-8 reduced P2O5 to 1.74-2.23% and increased the dephosphorization rate to 71.12%-77.88%, none of them could break through the 1.0% limit, and the lithium loss rate was generally higher than 30%, indicating that the single system only has basic adsorption capacity and lacks the ability to regulate surface properties through multi-mechanism coupling. Although Comparative Examples 9-11 increased the dephosphorization rate to 80.12%-81.02% and reduced P2O5 to 1.39-1.48%, there was still a significant gap from the target line, and the lithium loss rate was still as high as 26.69%-28.57%, indicating that the three components could only partially simulate the synergistic pathway and could not construct a complete inhibitory film.

[0135] In contrast, the quaternary systems in Comparative Examples 12-16, lacking any one component, exhibited a precipitous drop in performance, directly demonstrating that all five components are indispensable. Sodium polyacrylate provides calcium-magnesium chelation and a steric framework, alginate imparts specific hydrogen bond recognition to the crystal face, sulfate contributes a physical coating layer of metal hydroxide, sodium hexametaphosphate maintains colloidal dispersion stability, and sodium humate ensures interfacial adaptability in complex ionic environments. The five components complement each other, are sequentially connected, and are scale-integrated, together forming a technical closed loop to solve the beneficiation problem of the difficulty in separating homogeneous spodumene / lithium phosphate aluminum ore.

[0136] Taking into account the synergistic effect of the combination inhibitors of the present invention, Example 1 was selected as the preferred combination inhibitor formulation and ratio for subsequent experiments and tests.

[0137] Test Example 2

[0138] To verify the dephosphorization effect of different dosages in Example 1 under ultra-high phosphorus content conditions in lithium concentrate, this test used flotation lithium ore b from Sichuan province. Figure 1The process shown was used to dephosphorize lithium ore b by reverse flotation with different inhibitor dosages of 400 g / t, 800 g / t, 1200 g / t, and 1600 g / t. The flotation process parameters were the same in each group of cases, and the only difference was the dosage of the combined inhibitor. This was to explore the selectivity and inhibition effect of the combined inhibitors with different dosages in this case.

[0139] The specific operation is the same as that in Test Example 1, except that only the dosage of the combination inhibitor is changed.

[0140] Table 4 shows the separation effect of lithium ore b under different depressant dosages. The separation effect statistics are based on changes under roughing conditions, with the reverse flotation pulp pH at 7, the depressant dosage at 800 g / t, and the collector sodium oleate dosage at 400 g / t.

[0141] Table 4

[0142]

[0143] As shown in Table 4, the combined inhibitor of this invention exhibits significant and controllable dephosphorization efficiency in the ultra-high phosphorus lithium concentrate system (lithium ore b, with raw ore P2O5 reaching 7.67%): as the inhibitor dosage increases from 400 g / t to 1600 g / t, the P2O5 content in the spodumene concentrate shows a monotonically decreasing trend, continuously decreasing from 2.77% to 0.98%, and remaining consistently below the industry mandatory standard limit of 1.0% under all operating conditions. Crucially, the phosphorus removal rate simultaneously increases to 90.22% (1600 g / t), an increase of 11 percentage points compared to 78.78% at 400 g / t.

[0144] Furthermore, it is worth noting that when the inhibitor dosage is 1600 g / t, excellent results can be achieved with P2O5=0.98% and dephosphorization rate of 90.22%, and the lithium loss rate in tailings is only 23.31% at this time, achieving the best inhibition effect.

[0145] In summary, the combined inhibitor containing six components described in this invention can exert optimal synergistic effects when the appropriate ratio and formulation are used. It also has good reverse flotation dephosphorization effect on different types of high phosphorus and lithium concentrates, and can achieve selective separation of spodumene and phosphite, so that the P2O5 content in spodumene concentrate meets the non-ferrous metal industry standard and reduces the lithium loss rate in phosphite tailings.

[0146] Finally, it should be noted that the above-described embodiments are merely specific implementations of the present invention, used to illustrate the technical solutions of the present invention, and not to limit it. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the technical scope disclosed in the present invention, or make equivalent substitutions for some of the technical features; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A combination depressant for reverse flotation, characterized in that The reverse flotation combined inhibitor is used to separate spodumene and phosphate rock in lithium phosphate mines. The reverse flotation combination inhibitor, by weight, comprises 40-70 parts of polyacrylic acid and its salts, 10-40 parts of alginate, 10-30 parts of sulfate, 5-20 parts of sodium hexametaphosphate, and 5-15 parts of sodium humate.

2. The anti-flotation combination inhibitor according to claim 1, characterized in that, The reverse flotation combination inhibitor, by weight, comprises 45-70 parts of polyacrylic acid and its salts, 10-35 parts of alginate, 10-25 parts of sulfate, 5-15 parts of sodium hexametaphosphate, and 5-10 parts of sodium humate.

3. The anti-flotation combination inhibitor according to claim 1 or 2, characterized in that, The polyacrylic acid and its salts include polyacrylic acid and / or sodium polyacrylate; And / or, the polyacrylic acid and its salts are sodium polyacrylate; And / or, the molecular weight of the sodium polyacrylate is 1000~5000.

4. The anti-flotation combination inhibitor according to claim 1 or 2, characterized in that, The alginate includes sodium alginate and / or potassium alginate; And / or, the sulfate includes at least one of aluminum sulfate, ferric sulfate, ferrous sulfate and potassium aluminum sulfate.

5. A reverse flotation method for spodumene in lithium phosphate ores, characterized in that, The reverse flotation combination inhibitor described in any one of claims 1 to 4 is used to suppress spodumene in the lithium phosphate ore and reverse flotation of the phosphate aluminum ore to obtain spodumene concentrate and phosphate aluminum ore tailings.

6. The reverse flotation method according to claim 5, characterized in that, The dosage of the reverse flotation combination inhibitor is ≥500g / t; And / or, the amount of the reverse flotation combination inhibitor is 500~2000g / t; And / or, during the reverse flotation process, the pH of the slurry is 4 to 10.

7. The reverse flotation method according to claim 5, characterized in that, The reagents used in the reverse flotation also include collectors; And / or, the collector includes at least one of oleic acid, sodium oleate, tal oil, and oxidized paraffin soap; And / or, the amount of the collector used is 100~1000g / t.

8. The reverse flotation method according to any one of claims 5 to 7, characterized in that, The phosphorus-bearing lithium ore is obtained from lithium ore through positive flotation. And / or, the reagents used in the positive flotation include metal ion activators and fatty acid collectors.

9. The reverse flotation method according to claim 8, characterized in that, The metal ion activator includes at least one of calcium chloride, magnesium chloride, and ferric chloride.

10. The reverse flotation method according to claim 8, characterized in that, The fatty acid collector includes at least one of sodium oleate, oxidized paraffin soap, and naphthenic acid soap.

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