Method for attrition scrubbing and flotation of silicate minerals

Abstract

This invention provides a grinding and flotation separation method for silicate minerals. The method includes: grinding a mixture containing silicate minerals, nitrite, and a solvent using grinding media to induce a redox reaction during grinding, resulting in a slurry; and performing flotation separation on the slurry to obtain a concentrate and tailings; wherein at least one of the silicate minerals and the grinding media contains iron, and the iron is primarily Fe2+ or Fe3+. 2+ and Fe 3+ The slurry contains one or more of the following forms: the solid matter includes mineral particles and Fe3O4, and at least some of the mineral particles are coated with an H2SiO3 layer. Compared with the traditional "grinding + flotation separation" method, the method provided in this application can improve the separation efficiency and recovery rate of various metal elements and silicate products in silicate minerals.

Description

Technical Field

[0001] This invention relates to the field of mineral separation and processing technology, and more specifically, to a grinding and flotation separation method for silicate minerals. Background Technology

[0002] Silicate minerals generally refer to a class of oxyacid salt minerals formed by the combination of metal cations and silicate ions. Silicate minerals are crucial in the beneficiation and processing industries. On the one hand, they serve as important raw materials for the extraction of rare metals, such as beryllium from beryl, lithium from lepidolite and spodumene, and zircon and hafnium from zircon. On the other hand, silicate minerals themselves are important basic industrial raw materials, such as mica, kaolin, talc, wollastonite, and zeolite. In contemporary mineral processing, silicate mineral flotation is the most widely used separation method. However, as the grade of useful minerals in the feed ore decreases, the mineral coexistence becomes more complex, making the separation of silicate minerals more complicated. Among the challenges in silicate mineral grinding and flotation separation processes, controlling the precipitation and adsorption of iron species such as iron media or iron minerals during grinding is a common problem.

[0003] In neutral or alkaline iron-containing silicate mineral abrasion and flotation systems, Fe produced by process media loss and iron mineral abrasion and leaching tends to form Fe2+. 3+ / Fe 2+ Then it evolved into Fe(OH)3 with a large specific surface area and high adhesion / adsorption capacity. These species are very easy to adsorb on the surface of various silicate minerals due to the positive charge on their surface, thereby reducing the separation selectivity of silicate minerals and thus significantly affecting the separation efficiency of useful minerals and gangue minerals, especially for the flotation separation of silicate mineral aggregates containing different mineral types.

[0004] Currently, in order to suppress the influence of iron species on the flotation system of silicate minerals, the following two methods are mainly adopted: (1) Reduce or avoid the grinding loss of iron media by changing the media material, thereby reducing the influence of iron species; for example, Chinese Patent (Announcement No. CN109759224B) discloses a method to improve the grade of lepidolite flotation concentrate, which uses ceramic balls to finely grind the rough concentrate of lepidolite flotation, thereby reducing the contamination of iron species during the beneficiation process and improving the lithium grade; (2) Change the adsorption state of iron species on the mineral surface by using complexing modifiers to reduce the adsorption of iron species on the surface of silicate minerals; for example, Chinese Patent (Announcement No. CN107638959B) discloses a method for suppressing the flotation of silicate gangue minerals in fluorite, which uses carboxylic acid complexing agents such as oxalic acid, citric acid, and EDTA to reduce the adsorption of iron species on the surface of silicate minerals.

[0005] However, the above methods still have the following drawbacks: (1) Although the use of non-ferrous media grinding can improve the wear of iron media grinding, it cannot suppress the effect of dissolution of the original iron oxide species in the material, and its industrial application is still relatively narrow; (2) The use of wear-resistant steel balls is costly and will cause iron pollution; (3) In the method of changing the adsorption state of iron species on the mineral surface by complexing modifier, although the complex reacts with metal ions such as iron, calcium, and magnesium, it is easy to adsorb or dissolve surface cations, which makes the surface of useful minerals lose the active sites for capture.

[0006] Therefore, developing a novel grinding and flotation separation method for silicate minerals is of great significance for improving the separation efficiency and recovery rate of various metal elements and silicate products in minerals. Summary of the Invention

[0007] The main objective of this invention is to provide a grinding and flotation separation method for silicate minerals, in order to solve the problem that iron-containing substances have a significant impact on the silicate mineral flotation system in the prior art, resulting in low separation efficiency and low recovery rate of various metal elements and silicate products in the minerals.

[0008] To achieve the above objectives, the present invention provides a grinding and flotation separation method for silicate minerals, comprising: step S1, grinding a mixture containing silicate minerals, nitrite, and solvent using grinding media to induce a redox reaction during grinding to obtain a slurry; and step S2, flotation separation of the slurry to obtain a concentrate and tailings; wherein at least one of the silicate minerals and the grinding media contains iron, and the iron is primarily Fe2+ or Fe3+. 2+ and Fe 3+ It exists in one or more forms, the solid matter of the slurry includes mineral particles and Fe3O4, and at least some of the mineral particles are coated with an H2SiO3 layer.

[0009] Furthermore, the mass concentration of the mixture system is 45% to 70%; preferably, the solvent is water.

[0010] Furthermore, the nitrite content in the silicate minerals is 0.01–10 wt%.

[0011] Furthermore, the fineness of the solid materials in the slurry is 0.05–0.3 mm.

[0012] Furthermore, the grinding process takes 5–60 minutes and the pH is 6–12.

[0013] Furthermore, before step S1, the process of crushing the silicate mineral to obtain the crushed product is also included; preferably, the particle size of the crushed product is ≤10mm.

[0014] Furthermore, the silicate minerals are selected from one or more of the group consisting of spodumene, hematite, limonite, lepidolite, fluorite, serpentine, cassiterite, aegirine, kyanite, bauxite, kaolinite, beryl, garnet, and rare earth minerals.

[0015] Further, the flotation separation process includes: step S21, mixing the slurry with a first modifier, a first collector, and an optional first frother and performing roughing to obtain a roughing concentrate and roughing tailings; step S22, mixing the roughing concentrate with a second modifier, an optional second collector, and an optional second frother and performing cleaning to obtain a concentrate and cleaned tailings; preferably, at least a portion of the cleaned tailings is returned to step S22 for reuse; step S23, mixing the roughing tailings with a third modifier, a third collector, and an optional third frother and performing scavenging to obtain tailings and scavenging froth; preferably, at least a portion of the scavenging froth is returned to step S23 or step S21 for reuse; preferably, the flotation separation process is selected from a direct flotation process or a reverse flotation process.

[0016] Furthermore, when the flotation separation is a positive flotation process, the first, second, and third modifiers are each independently selected from one or more of the group consisting of sodium carbonate, sodium hydroxide, sodium sulfide, sodium hexametaphosphate, sodium silicate, calcium chloride, magnesium chloride, ferric chloride, aluminum chloride, lead nitrate, and copper sulfate; and / or, the first, second, and third collectors are each independently selected from fatty acid compounds, organic sulfonate compounds, organic sulfate compounds, organic amine compounds, organic phosphonic acid compounds, and purine compounds, preferably oleic acid, sodium oleate, epoxy acid, oxidized paraffin soap, epoxy acid soap, salicylic acid, alkyl hydroxamic acid, tributyl phosphate, etc. One or more of the following groups are included: styrenephosphonic acid, sodium dodecyl sulfonate, sodium dodecyl sulfate, dodecylamine, and adenine compounds; and / or, the first frother, the second frother, and the third frother are each independently selected from one or more of the following groups: fusel oils, ether alcohols, and pyridine compounds; preferably, one or more of the following groups are included: No. 2 oil, methyl isobutyl methanol, and n-octanol; preferably, step S22 further includes: sequentially performing a first cleaning, a second cleaning, and a third cleaning on the roughing concentrate to obtain a concentrate; and / or, step S23 further includes: sequentially performing a first scavenging and a second scavenging on the roughing tailings to obtain tailings and scavenging foam.

[0017] Further, when the flotation separation is a reverse flotation process, the first, second, and third modifiers are each independently selected from one or more of the group consisting of caustic starch, dextrin, guar gum, carboxymethyl cellulose, and tannin compounds; and / or, the first, second, and third collectors are each independently selected from amine compounds, preferably one or more of the group consisting of dodecylamine, tetradecylamine, octadecylamine, and etheramine; and / or, the first, second, and third frothers are each independently selected from one or more of the group consisting of fusel oils, ether alcohols, and pyridine compounds; preferably one or more of the group consisting of No. 2 oil, methyl isobutyl methanol, and n-octanol; preferably, step S22 further includes: sequentially performing a first cleaning and a second cleaning on the rougher concentrate to obtain concentrate; and / or, step S23 further includes: sequentially performing a first scavenging and a second scavenging on the rougher tailings to obtain tailings and scavenging froth.

[0018] By applying the technical solution of this invention, the grinding process provided in this application can, on the one hand, reduce the mineral particle size and achieve the purpose of mineral liberation; on the other hand, the introduction of nitrite can reduce the iron-containing substances (Fe, Fe) in silicate minerals and / or grinding media. 2+ and Fe 3+ One or more of the following reactants undergo a redox reaction with nitrite, and utilize the localized high energy difference generated by the collision of grinding media to activate the directional transformation of the activated reactants, thereby promoting the transformation of iron-containing substances into highly crystalline Fe3O4, while inhibiting the formation of iron hydroxides. This suppresses the adsorption of iron hydroxides on the surface of the ore particles, reducing the adverse effects of low separation efficiency caused by the adsorption of iron hydroxides in subsequent flotation separation processes. Furthermore, the ammonia compounds and their derivative ions NH4+ generated during this process... + NH4 selectively adsorbs onto the surface of mineral particles. + SiO3 formed by the breaking of Si-O bonds in mineral particles 2- Double hydrolysis occurs, resulting in an H2SiO3 layer or a SiO2·H2O layer coating on the surface of the mineral particles, which facilitates efficient separation by utilizing the surface properties of different minerals in subsequent flotation separation processes.

[0019] In summary, compared with the traditional "grinding + flotation separation" method, the method provided in this application can improve the separation efficiency and recovery rate of various metal elements and silicate products in silicate minerals. Attached Figure Description

[0020] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0021] Figure 1 A schematic diagram of the grinding and flotation separation method for low-grade spodumene ore in Example 1 is shown;

[0022] Figure 2 A schematic diagram of the conventional grinding and flotation separation method for low-grade spodumene ore in Comparative Example 1 is shown.

[0023] Figure 3 A schematic diagram of the grinding and flotation separation method for oolitic hematite in Example 5 is shown. Detailed Implementation

[0024] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the embodiments.

[0025] As described in the background section, existing silicate mineral flotation separation processes suffer from problems such as the significant impact of iron-containing substances on the silicate mineral flotation system, low separation efficiency, and low recovery rate of various metal elements and silicate products in the minerals. To address these technical problems, this application provides a grinding-flotation separation method for silicate minerals, comprising: step S1, grinding a mixture containing silicate minerals, nitrite, and a solvent using grinding media to induce a redox reaction during grinding, yielding a slurry; and step S2, flotation separation of the slurry to obtain a concentrate and tailings; wherein at least one of the silicate minerals and the grinding media contains iron, with the iron element primarily composed of Fe2+ and Fe3+. 2+ and Fe 3+ It exists in one or more forms, the solid matter of the slurry includes mineral particles and Fe3O4, and at least some of the mineral particles are coated with an H2SiO3 layer.

[0026] The grinding process described in this application can, on the one hand, reduce mineral particle size and achieve mineral liberation; on the other hand, the introduction of nitrite can neutralize iron-containing substances (Fe, Fe2+) in silicate minerals and / or grinding media. 2+ and Fe 3+ One or more of the following reactants undergo a redox reaction with nitrite, and utilize the localized high energy difference generated by the collision of grinding media to activate the directional transformation of the activated reactants, thereby promoting the transformation of iron-containing substances into highly crystalline Fe3O4, while inhibiting the formation of iron hydroxides. This suppresses the adsorption of iron hydroxides on the surface of the ore particles, reducing the adverse effects of low separation efficiency caused by the adsorption of iron hydroxides in subsequent flotation separation processes. Furthermore, the ammonia compounds and their derivative ions NH4+ generated during this process... + NH4 selectively adsorbs onto the surface of mineral particles. + SiO3 formed by the breaking of Si-O bonds in mineral particles2- Double hydrolysis occurs, resulting in an H2SiO3 layer or a SiO2·H2O layer coating on the surface of the mineral particles, which facilitates efficient separation by utilizing the surface properties of different minerals in subsequent flotation separation processes.

[0027] During the grinding process described above, the following chemical reactions or electrochemical processes occur (vs. NHE):

[0028] (1)9Fe+4NaNO2+12H2O→3Fe3O4+NaOH+4NH3·H2O;

[0029] (2)9Fe 2+ +4NaNO2+12H2O+18e→4NH3·H2O+3Fe3O4+4NaOH;

[0030] (3)9Fe 3+ +4NaNO2+12H2O+27e→4NH3·H2O+3Fe3O4+4NaOH;

[0031] (4) NO3 - +NO+e→2NO2 - E 0 = -0.58V;

[0032] (5) NO2 - +H₂O + e → NO + 2OH⁻ - E 0 = -0.46V;

[0033] (6)2NO2 - +3H₂O + 4e → N₂O + 6OH⁻ - E 0 =0.15V;

[0034] (7) N₂O + 5H₂O + 4e → 2NH₂OH + 4OH⁻ - E 0 = -1.05V;

[0035] (8)NH2OH+2H2O+2e→NH3·H2O+2OH - E 0 =0.42V;

[0036] (9)2NH4 + +SiO3 2- +2H2O→2NH3·H2O+H2SiO3;

[0037] (10)NH4 + →NH3+H + ;

[0038] (11)SiO3 2- +2H + →H2SiO3.

[0039] In summary, compared with the traditional "grinding + flotation separation" method, the method provided in this application can improve the separation efficiency and recovery rate of various metal elements and silicate products in silicate minerals.

[0040] In a preferred embodiment, the mass concentration of the mixture system is 45% to 70%. The mass concentration of the mixture system includes, but is not limited to, the above range. Limiting it to this range is beneficial for reducing mineral particle size, improving mineral liberation, promoting the transformation of iron-containing substances into highly crystalline Fe3O4, and inhibiting the formation of iron hydroxides. This helps to suppress the adsorption of iron hydroxides on the surface of mineral particles, reducing the adverse effects of low separation efficiency caused by the adsorption of iron hydroxides during subsequent flotation separation. Furthermore, it helps to increase the concentration of NH4+. + With SiO3 2- The hydrolysis efficiency of double hydrolysis is beneficial to increasing the coating amount of H2SiO3 on the surface of mineral particles, thereby improving the separation efficiency and recovery rate of various metal elements and silicate products in silicate minerals.

[0041] In a preferred embodiment, the solvent is water. Using water as the solvent facilitates the dissolution of nitrites, improves their dispersibility, and also enhances the processability of the mixture system.

[0042] In a preferred embodiment, the nitrite content of the silicate mineral is 0.01–10 wt%. The amount of nitrite used includes, but is not limited to, the above range. Limiting it within this range is beneficial for further promoting the transformation of iron-containing substances into highly crystalline Fe3O4, and for further inhibiting the formation of iron hydroxides. This, in turn, helps to further inhibit the adsorption of iron hydroxides on the surface of the ore particles, and further reduces the adverse effects of low separation efficiency caused by the adsorption of iron hydroxides during subsequent flotation separation. Furthermore, it helps to further improve the NH4+ content. + With SiO3 2- The hydrolysis efficiency of double hydrolysis is conducive to further increasing the coating amount of H2SiO3 on the surface of mineral particles, thereby further improving the separation efficiency and recovery rate of various metal elements and silicate products in silicate minerals.

[0043] In a preferred embodiment, when the silicate mineral is spodumene, the nitrite content of the silicate mineral is 0.01 to 1.0 wt%. The amount of nitrite used includes, but is not limited to, the above range. Limiting it within the above range is beneficial to further improve the separation efficiency and recovery rate of various metal elements and silicate products in the silicate mineral.

[0044] In a preferred embodiment, the fineness of the solid material in the slurry is 0.05–0.3 mm. The fineness of the solid material in the slurry includes, but is not limited to, the above range. Limiting it to this range facilitates subsequent flotation separation, thereby improving the separation efficiency and recovery rate of various metal elements and silicate products in silicate minerals.

[0045] In a preferred embodiment, the grinding process takes 5–60 minutes, and the pH is 6–12. The grinding time and pH include, but are not limited to, the above ranges. Limiting them to these ranges is beneficial for further promoting the transformation of iron-containing substances into highly crystalline Fe3O4, and for further inhibiting the formation of iron hydroxides. This, in turn, helps to further suppress the adsorption of iron hydroxides on the surface of the ore particles, and further reduces the adverse effects of low separation efficiency caused by the adsorption of iron hydroxides during subsequent flotation separation. Furthermore, it helps to further increase the NH4+ content. + With SiO3 2- The hydrolysis efficiency of double hydrolysis is conducive to further increasing the coating amount of H2SiO3 on the surface of mineral particles, thereby further improving the separation efficiency and recovery rate of various metal elements and silicate products in silicate minerals.

[0046] In a preferred embodiment, step S1 is preceded by a process of crushing the silicate minerals to obtain crushed products. Compared to grinding the raw ore directly, crushing first helps reduce the particle size of the silicate minerals, thereby improving their processability, while also reducing the weight of the grinding media consumed, facilitating subsequent grinding.

[0047] To further improve the processability of silicate minerals and further reduce the weight of grinding media consumption, preferably, the particle size of the crushed product is ≤10mm.

[0048] The solutions provided in this application are widely applicable to various silicate minerals. In a preferred embodiment, the silicate minerals include, but are not limited to, one or more of the following groups: spodumene, hematite, limonite, lepidolite, fluorite, serpentine, cassiterite, aegirine, kyanite, bauxite, kaolinite, beryl, garnet, and rare earth minerals. The solutions provided in this application are particularly applicable to the aforementioned types of silicate minerals.

[0049] In a preferred embodiment, the flotation separation process includes: step S21, mixing the slurry with a first modifier, a first collector, and optionally a first frother and performing roughing to obtain a rough concentrate and rough tailings; step S22, mixing the rough concentrate with a second modifier, optionally a second collector, and optionally a second frother and performing cleaning to obtain a concentrate and cleaned tailings; preferably, at least a portion of the cleaned tailings is returned to step S22 for reuse; step S23, mixing the rough tailings with a third modifier, a third collector, and optionally a third frother and performing scavenging to obtain tailings and scavenging froth; preferably, at least a portion of the scavenging froth is returned to step S23 or step S21 for reuse.

[0050] In a preferred embodiment, the flotation separation process includes, but is not limited to, a forward flotation process or a reverse flotation process.

[0051] In the aforementioned direct flotation separation process, the first collector adsorbs H2SiO3 and its activation and adjustment reaction products onto the surface of the mineral particles in the pulp. Simultaneously, the first frother and the first collector combine and adsorb onto the surface of the mineral particles, causing them to float and thus yielding the flotation froth product, which is the concentrate. For example, in a spodumene direct flotation system, this process facilitates subsequent Ca adsorption. 2+ / Mg 2+ The formation of Ca / MgSiO3 increases the adsorption probability of the anionic collector RCOO- on the surface of Ca / MgSiO3, thereby improving flotation efficiency. On the other hand, it can also play a role in dispersing particles, which is conducive to the reaction between mineral particles and reagents. When using the first collector to directly capture H2SiO3 for flotation, cationic amine collectors are more suitable, that is, the formation of such a surface can directly improve the collection of silicate mineral particles by cations, thereby improving flotation efficiency.

[0052] In a preferred embodiment, when the flotation separation is a positive flotation process, the first, second, and third modifiers are each independently including, but not limited to, one or more of the group consisting of sodium carbonate, sodium hydroxide, sodium sulfide, sodium hexametaphosphate, sodium silicate, calcium chloride, magnesium chloride, ferric chloride, aluminum chloride, lead nitrate, and copper sulfate; and / or, the first, second, and third collectors are each independently including, but not limited to, fatty acid compounds, organic sulfonate compounds, organic sulfate compounds, organic amine compounds, organic phosphonic acid compounds, and purine compounds. The compound is preferably one or more of the following groups: oleic acid, sodium oleate, epoxy acid, oxidized paraffin soap, epoxy acid soap, salicylic acid, alkyl hydroxamic acid, tributyl phosphate, styrene phosphonic acid, sodium dodecyl sulfonate, sodium dodecyl sulfate, dodecylamine, and adenine compounds; and / or, the first, second, and third frothers are each independently, but not limited to, one or more of the following groups: fusel oil, ether alcohols, and pyridine compounds; preferably, one or more of the following groups: No. 2 oil, methyl isobutyl methanol (MIBC), and n-octanol. Compared to other types, using the above-mentioned types of modifiers, collectors, and frothers is beneficial for improving flotation separation efficiency.

[0053] To further improve flotation separation efficiency, in a preferred embodiment, when the flotation separation is a direct flotation process, step S22 further includes: sequentially performing a first cleaning, a second cleaning, and a third cleaning on the rougher concentrate to obtain a concentrate; and / or, step S23 further includes: sequentially performing a first scavenging and a second scavenging on the rougher tailings to obtain tailings and scavenging froth. Preferably, in the direct flotation process, the time for the first cleaning is 2–10 min, the time for the second cleaning is 2–8 min, and the time for the third cleaning is 2–8 min. Preferably, in the direct flotation process, the time for the first scavenging is 2–10 min, and the time for the second scavenging is 2–10 min.

[0054] In a preferred embodiment, when the flotation separation is a reverse flotation process, the first, second, and third modifiers are each independently including, but not limited to, one or more compounds from the group consisting of caustic starch, dextrin, guar gum, carboxymethyl cellulose, and tannins; the first, second, and third collectors are each independently including, but not limited to, amine compounds, preferably one or more from the group consisting of dodecylamine, tetradecylamine, octadecylamine, and etheramines; the first, second, and third frothers are each independently including, but not limited to, one or more from the group consisting of fusel oils, ether alcohols, and pyridines; preferably, one or more from the group consisting of No. 2 oil, methyl isobutyl methanol, and n-octanol. Compared to other types, using the above-mentioned modifiers, collectors, and frothers is beneficial for improving flotation separation efficiency.

[0055] In the above-mentioned reverse flotation separation process, the first collector adsorbs silicate minerals in the pulp. For example, Fe3O4 generated by the reaction of target minerals such as hematite during the grinding process is highly hydrophilic and is not collected and floated by the first collector. At the same time, the first frother and the first collector are combined and adsorbed on the surface of silicate minerals, causing the silicate minerals to float, thereby obtaining flotation froth products, i.e. tailings.

[0056] To further improve flotation separation efficiency, in a preferred embodiment, when the flotation separation is a reverse flotation process, step S22 further includes: sequentially performing a first cleaning and a second cleaning on the rougher concentrate to obtain a concentrate; and / or, step S23 further includes: sequentially performing a first scavenging and a second scavenging on the rougher tailings to obtain tailings and scavenging froth. Preferably, in the reverse flotation process, the first cleaning time is 2–10 min, the second cleaning time is 2–8 min, and the third cleaning time is 2–8 min. Preferably, in the reverse flotation process, the first scavenging time is 2–10 min, and the second scavenging time is 2–10 min.

[0057] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.

[0058] (I) Direct Flotation Process

[0059] Example 1

[0060] A grinding and flotation separation method for a low-grade spodumene ore includes:

[0061] (1) A low-grade spodumene ore was prepared, with a Li2O content of 1.30% in the raw ore. The lithium mineral is mainly spodumene, containing iron minerals such as limonite, pyrite, and hematite. The gangue minerals are mainly quartz, muscovite, and albite, with small amounts of grossular, apatite, calcite, chlorite, amphibole, potassium feldspar, and albite. This low-grade spodumene ore contains 1.5 wt% Fe, 20 wt% Si, 15 wt% Al, 1.5 wt% Na, and 1.5 wt% K.

[0062] (2) The spodumene ore was crushed to a particle size of 2 mm to obtain the crushed product;

[0063] (3) Weigh out sodium nitrite with a weight percentage of 0.2 wt% of the spodumene ore, mix the weighed sodium nitrite with grinding media, spodumene ore and water, the grinding media is cast iron, and grind in a grinding mill; wherein, the mass concentration of the mixture system containing sodium nitrite, spodumene ore and water is 55%; after grinding for 9 min, a slurry with a fineness of -0.074 mm accounting for 70% is obtained;

[0064] (4) Figure 1 As shown, a flotation process consisting of one rougher, three cleaners, and two scavengers was used to recover spodumene, yielding lithium concentrate and tailings. The lithium concentrate contained 6.0% Li2O and 1.29% TFe, with a Li2O recovery rate of 88.4%.

[0065] The flotation separation process conditions and reagent dosages in Example 1 are shown in Table 1.

[0066] Comparative Example 1

[0067] The difference from Example 1 is that: [the method used is as follows] Figure 2 The conventional grinding and flotation separation method shown is used for processing, in which sodium nitrite is not introduced during the grinding process, and the dosage of the modifier, the type and dosage of the collector are different from those in Example 1. The grinding and flotation separation process conditions and the dosage of each reagent in Comparative Example 1 are shown in Table 1.

[0068] The lithium concentrate contained 5.2% Li2O and 3.02% TFe, with a Li2O recovery rate of 80.4%.

[0069] Comparative Example 2

[0070] The difference from Example 1 is that the same grinding-flotation separation method as Comparative Example 1 was used, except that sodium nitrite was not introduced during the grinding process, and the dosage of the modifier, the type and dosage of the collector were different from those in Example 1. The grinding-flotation separation process conditions and the dosage of each reagent are shown in Table 1.

[0071] The lithium concentrate contained 5.1% Li2O and 3.12% TFe, with a Li2O recovery rate of 81.3%.

[0072] Table 1

[0073]

[0074] Example 2

[0075] The difference from Example 1 is that the sodium nitrite content in the low-grade spodumene ore is 0.01 wt%.

[0076] The lithium concentrate contained 5.4% Li2O and 2.9% TFe, with a Li2O recovery rate of 82.3%.

[0077] Example 3

[0078] The difference from Example 1 is that the sodium nitrite content in the low-grade spodumene ore is 1.0 wt%.

[0079] The lithium concentrate contained 6.0% Li2O and 1.25% TFe, with a Li2O recovery rate of 88.3%.

[0080] Example 4

[0081] The difference from Example 1 is that the sodium nitrite content in the low-grade spodumene ore is 0.005 wt%.

[0082] The lithium concentrate contained 5.2% Li2O and 1.23% TFe, with a Li2O recovery rate of 80.0%.

[0083] (II) Reverse Flotation Process

[0084] Example 5

[0085] A grinding and flotation separation method for a certain oolitic hematite includes:

[0086] (1) Prepare oolitic hematite, in which the mass content of TFe is 42.3wt%, the mass content of P element is 0.5wt%, the mass content of SiO2 is 13.5wt%, and the mass content of Al2O3 is 11.3wt%. In this oolitic hematite, Fe is in various forms such as nodular, kidney-shaped, massive, star-shaped, and disseminated pseudomorphic hematite, magnetite, and hematite. The silicate minerals are kaolinized aluminosilicates, quartz, carbonate minerals, etc., and the mineral composition is complex.

[0087] (2) The oolitic hematite ore was crushed to a particle size of 3 mm to obtain the crushed product;

[0088] (3) Weigh out sodium nitrite with a weight percentage of 10.0 wt% of the oolitic hematite ore, mix the weighed sodium nitrite with grinding media, oolitic hematite ore and water. The grinding media is cast iron. Grind in a grinding mill. The mass concentration of the mixture containing sodium nitrite, oolitic hematite ore and water is 45%. After grinding for 8 minutes, a slurry with a fineness of -0.038 mm accounting for 80% is obtained.

[0089] (4) Figure 3 As shown, a reverse flotation process with one roughing, three cleaning, and two scavenging stages is used to recover iron, yielding iron-containing concentrate slag and tailings slag; the Fe content of the iron concentrate product reaches 63.3%, and the iron recovery rate is 70.2%.

[0090] (5) Filter the iron concentrate slag and tailings slag to obtain gangue minerals and iron concentrate respectively; among them, the TFe content in the iron concentrate is 65.4% and the recovery rate is 85.3%.

[0091] The flotation separation process conditions and reagent dosages for Example 5 are shown in Table 2.

[0092] Comparative Example 3

[0093] The difference from Example 5 is that the iron concentrate was extracted by traditional magnetization roasting-strong magnetic-reverse flotation, and the TFe content in the iron concentrate was 65.3% with a recovery rate of 82.0%.

[0094] The flotation separation process conditions and reagent dosages for Comparative Example 3 are shown in Table 2. The processing flow is also a one-roughing-three-cleansing-two-scavenging reverse flotation process.

[0095] Table 2

[0096]

[0097] As can be seen from the above description, the embodiments of the present invention achieve the following technical effects:

[0098] Comparing Example 1 with Comparative Examples 1 and 2 and their beneficiation indices, it can be seen that the grinding-flotation separation method provided in this application can significantly improve the grade of lithium concentrate and increase the recovery rate of lithium oxide. Moreover, the flotation separation is mainly manifested in the separation of spodumene from feldspar and quartz, and iron impurities have a significant impact on the flotation process.

[0099] Comparing Example 5 and Comparative Example 3 with their beneficiation indices, it can be seen that the TFe grade of the iron concentrate obtained by conventional magnetized roasting-strong magnetic-reverse flotation is increased by 1.2%, and the Fe recovery rate is increased by 4.5%. This shows that the grinding and flotation separation method provided in this application can effectively separate gangue minerals from iron minerals.

[0100] The grinding process described in this application can, on the one hand, reduce mineral particle size and achieve mineral liberation; on the other hand, the introduction of nitrite can neutralize iron-containing substances (Fe, Fe2+) in silicate minerals and / or grinding media. 2+ and Fe 3+ One or more of the following reactants undergo a redox reaction with nitrite, and utilize the localized high energy difference generated by the collision of grinding media to activate the directional transformation of the activated reactants, thereby promoting the transformation of iron-containing substances into highly crystalline Fe3O4, while inhibiting the formation of iron hydroxides. This suppresses the adsorption of iron hydroxides on the surface of the ore particles, reducing the adverse effects of low separation efficiency caused by the adsorption of iron hydroxides in subsequent flotation separation processes. Furthermore, the ammonia compounds and their derivative ions NH4+ generated during this process... + NH4 selectively adsorbs onto the surface of mineral particles. + SiO3 formed by the breaking of Si-O bonds in mineral particles 2- Double hydrolysis occurs, resulting in an H2SiO3 layer or a SiO2·H2O layer coating on the surface of the mineral particles, which facilitates efficient separation by utilizing the surface properties of different minerals in subsequent flotation separation processes.

[0101] It should be noted that the terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of this application described herein can be implemented, for example, in a sequence other than those described herein.

[0102] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A grinding and flotation separation method for silicate minerals, characterized in that, The grinding and flotation separation method for the silicate minerals includes: Step S1: Grind the mixture containing the silicate minerals, nitrites and solvents using grinding media to induce a redox reaction during the grinding process and obtain a slurry. Step S2: The slurry is subjected to flotation separation to obtain concentrate and tailings; Wherein, at least one of the silicate mineral and the grinding media contains iron, and the iron is mainly Fe2+, Fe3+, ...3+, Fe3+, 2+ and Fe 3+ The slurry exists in one or more forms, and the solid material of the slurry includes mineral particles and Fe3O4, and at least a portion of the mineral particles are coated with an H2SiO3 layer.

2. The grinding and flotation separation method for silicate minerals according to claim 1, characterized in that, The mass concentration of the mixture system is 45% to 70%.

3. The grinding and flotation separation method for silicate minerals according to claim 1, characterized in that, The solvent is water.

4. The grinding and flotation separation method for silicate minerals according to claim 1 or 2, characterized in that, The nitrite content of the silicate mineral is 0.01 to 10 wt%.

5. The grinding and flotation separation method for silicate minerals according to claim 1, characterized in that, The fineness of the solid material in the slurry is 0.05 to 0.3 mm.

6. The grinding and flotation separation method for silicate minerals according to claim 5, characterized in that, The grinding process takes 5–60 minutes and the pH is 6–12.

7. The grinding and flotation separation method for silicate minerals according to claim 1, characterized in that, Before step S1, the process of crushing the silicate mineral to obtain the crushed product is also included.

8. The grinding and flotation separation method for silicate minerals according to claim 7, characterized in that, The particle size of the crushed product is ≤10mm.

9. The grinding and flotation separation method for silicate minerals according to claim 7, characterized in that, The silicate minerals are selected from one or more of the group consisting of spodumene, hematite, limonite, lepidolite, fluorite, serpentine, cassiterite, aegirine, kyanite, bauxite, kaolinite, beryl, garnet, and rare earth minerals.

10. The grinding and flotation separation method for silicate minerals according to claim 1, characterized in that, The flotation separation process includes: Step S21: The slurry is mixed with the first modifier, the first collector and the first frother and then roughed to obtain rough concentrate and rough tailings. Step S22: The rough concentrate is mixed with the second modifier, the second collector and the second frother and then finely treated to obtain the concentrate and finely treated tailings; Step S23: The roughing tailings are mixed with the third modifier, the third collector and the third frother and then scavenged to obtain the tailings and scavenging foam.

11. The grinding and flotation separation method for silicate minerals according to claim 10, characterized in that, At least a portion of the selected tailings is returned to step S22 for reuse.

12. The grinding and flotation separation method for silicate minerals according to claim 10, characterized in that, At least a portion of the scavenged foam is returned to step S23 or step S21 for reuse.

13. The grinding and flotation separation method for silicate minerals according to claim 10, characterized in that, The flotation separation process is selected from either direct flotation or reverse flotation.

14. The grinding and flotation separation method for silicate minerals according to claim 13, characterized in that, When the flotation separation is the positive flotation process, the first modifier, the second modifier, and the third modifier are each independently selected from one or more of the group consisting of sodium carbonate, sodium hydroxide, sodium sulfide, sodium hexametaphosphate, sodium silicate, calcium chloride, magnesium chloride, ferric chloride, aluminum chloride, lead nitrate, and copper sulfate.

15. The grinding and flotation separation method for silicate minerals according to claim 13, characterized in that, When the flotation separation is the positive flotation process, the first collector, the second collector, and the third collector are each independently selected from fatty acid compounds, organic sulfonate compounds, organic sulfate compounds, organic amine compounds, organic phosphonic acid compounds, and purine compounds.

16. The grinding and flotation separation method for silicate minerals according to claim 15, characterized in that, When the flotation separation is the positive flotation process, the first collector, the second collector, and the third collector are each independently selected from one or more of the group consisting of oleic acid, sodium oleate, epoxy acid, oxidized paraffin soap, epoxy acid soap, salicylic acid, alkyl hydroxamic acid, tributyl phosphate, styrene phosphonic acid, sodium dodecyl sulfonate, sodium dodecyl sulfate, dodecylamine, and adenine compounds.

17. The grinding and flotation separation method for silicate minerals according to claim 13, characterized in that, When the flotation separation is the positive flotation process, the first frother, the second frother, and the third frother are each independently selected from one or more of the group consisting of fusel alcohols, ether alcohols, and pyridines.

18. The grinding and flotation separation method for silicate minerals according to claim 17, characterized in that, When the flotation separation is the positive flotation process, the first frother, the second frother, and the third frother are each independently one or more of the group consisting of No. 2 oil, methyl isobutyl methanol, and n-octanol.

19. The grinding and flotation separation method for silicate minerals according to claim 13, characterized in that, When the flotation separation is the positive flotation process, step S22 further includes: sequentially performing a first cleaning, a second cleaning, and a third cleaning on the rougher concentrate to obtain the concentrate.

20. The grinding and flotation separation method for silicate minerals according to claim 13, characterized in that, When the flotation separation is the positive flotation process, step S23 further includes: performing a first scavenging and a second scavenging on the roughing tailings in sequence to obtain the tailings and the scavenging foam.

21. The grinding and flotation separation method for silicate minerals according to claim 13, characterized in that, When the flotation separation is the reverse flotation process, the first modifier, the second modifier, and the third modifier are each independently selected from one or more compounds in the group consisting of caustic starch, dextrin, guar gum, carboxymethyl cellulose, and tannins.

22. The grinding and flotation separation method for silicate minerals according to claim 13, characterized in that, When the flotation separation is the reverse flotation process, the first collector, the second collector, and the third collector are each independently selected from amine compounds.

23. The grinding and flotation separation method for silicate minerals according to claim 22, characterized in that, When the flotation separation is the reverse flotation process, the first collector, the second collector, and the third collector are each independently one or more of the group consisting of dodecylamine, tetradecylamine, octadecylamine, and etheramine.

24. The grinding and flotation separation method for silicate minerals according to claim 13, characterized in that, When the flotation separation is the reverse flotation process, the first frother, the second frother, and the third frother are each independently selected from one or more of the group consisting of fusel alcohols, ether alcohols, and pyridines.

25. The grinding and flotation separation method for silicate minerals according to claim 24, characterized in that, When the flotation separation is the reverse flotation process, the first frother, the second frother, and the third frother are each independently one or more of the group consisting of No. 2 oil, methyl isobutyl methanol, and n-octanol.

26. The grinding and flotation separation method for silicate minerals according to claim 13, characterized in that, When the flotation separation is the reverse flotation process, step S22 further includes: performing a first cleaning and a second cleaning sequentially on the rougher concentrate to obtain the concentrate.

27. The grinding and flotation separation method for silicate minerals according to claim 13, characterized in that, When the flotation separation is the reverse flotation process, step S23 further includes: performing a first scavenging and a second scavenging on the roughing tailings in sequence to obtain the tailings and the scavenging foam.

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