Method of flotation pre-enrichment and magnetic separation of low-grade iron-lithium mica ore

Abstract

FIELD: processing mineral raw materials.SUBSTANCE: method of flotation pre-concentration and magnetic separation of low-grade iron-lithium mica ore includes the following stages: (1) crushing and coarse grinding of low-grade iron-lithium mica ore, followed by adding clean water to adjust the mass concentration of the ore pulp within the range of 28-40%, (2) adding a combined modifier and a combined collector to the ore pulp obtained in step (1), followed by carrying out the operation of primary rough enrichment in a flotation column, (3) adding a combined modifier and a combined collector to the tailings of primary rough enrichment in a flotation column obtained in step (2), followed by carrying out secondary rough enrichment in a flotation column, (4) combining the concentrate of primary rough enrichment in a flotation column obtained in step (2) and the concentrate of secondary rough enrichment in a flotation column obtained in step (3) to obtain a coarse-fraction lithium rough concentrate, followed by pulp preparation, foaming and fine grinding, and also adding clean water to regulate the mass concentration of the ore pulp to 10-20%, (5) carrying out primary magnetic separation in a high-gradient separator of the ore pulp obtained in step (4), (6) carrying out secondary magnetic separation in a high-gradient separator of the primary magnetic separation tailings obtained in step (5), (7) combining the primary magnetic separation concentrate obtained in step (5) and the secondary magnetic separation concentrate obtained in step (6). The combined modifier is a mixture of sodium carbonate and sodium hexametaphosphate, and the combination collector is a mixture of lauryl amine acetate, sodium coco-sulfate, di(hydroxyethyl)methyldodecyl ammonium chloride and sodium ethoxylated alkyl sulfate.EFFECT: increase in the efficiency of extracting low-grade iron-lithium mica.8 cl, 1 dwg, 3 ex

Description

[0001] TECHNICAL AREA

[0002] The present invention relates to a method for flotation pre-concentration and magnetic separation of low-grade iron-lithium mica ore and relates to the technical field of mineral processing.

[0003] STATE OF THE ART

[0004] Lithium iron mica is an important source of lithium and is often found in association with white mica, feldspar, quartz, and calcium-bearing carbonates as gangue minerals. It is characterized by low lithium content, high impurity content, and complex inter-mineral inclusions. Particularly problematic is that the white mica, co-present in the ore, has a virtually identical crystal lattice and similar surface properties to lithium iron mica, and its interaction mechanism with reagents is similar, making effective separation impossible using flotation technology alone. As a result, the lithium concentrate obtained in this manner is of low quality, hindering its commercialization.

[0005] Due to the high degree of weathering and pronounced formation of clay components in iron-lithium mica deposits, its mineralogical properties become complex. In production, the separation process is typically controlled by increasing the number of flotation stages or adding large amounts of reagents. However, this leads to a longer flotation process, an increased number of reagent injection points, higher investment costs, and more complex operation. Furthermore, the large amount of slime in iron-lithium mica ore affects reagent selectivity, mineralization rate, foam viscosity, middle fraction circulation, and the rheological properties of the ore pulp. The presence of slime increases the stability and viscosity of the foam in flotation machines: the froth layer becomes heavy and poorly mobile, and excess foam causes a serious phenomenon of "overflow over the edges of the trough." At the same time, the slime constantly circulates and accumulates.

[0006] in the standard flotation process, which reduces the separation efficiency of iron-lithium mica and makes flotation difficult.

[0007] Patent CN 117753549 A describes a process for recovering low-grade iron-lithium mica ore using a "classified magnetic separation + flotation" process. However, patent CN 117753549 A does not specifically optimize the process for "highly slime-containing" ore during magnetic separation to prevent the negative impact of slime. In the recovery process described in patent CN 117753549 A, all feedstock ores must undergo magnetic separation, and some materials must also be flotation. The overall processing efficiency is higher, but energy consumption is also higher. In addition, when using conventional flotation reagents and the presence of reverse circulation of intermediate products, slime circulation cannot be avoided, affecting the separation efficiency.

[0008] Therefore, there is a pressing need to develop new technological processes and equipment that match the properties of low-grade iron-lithium mica ore, as well as to create environmentally friendly and highly effective flotation reagents capable of specifically regulating the characteristics of the solid and liquid phases, ore pulp conditions, and foam properties. This will enable the cost-effective and efficient recovery of low-grade iron-lithium mica and provide technological support for the environmentally friendly, low-carbon, and highly efficient utilization of complex and refractory lithium ores.

[0009] SUMMARY OF THE INVENTION

[0010] Due to the fact that traditional technologies have a number of problems in processing low-grade iron-lithium mica ore, such as a long flotation process, a large number of reagent addition points, a significant influence of the middle fraction, instability of the production process and low recovery rates, the present invention provides a method for flotation pre-concentration and magnetic separation of low-grade iron-lithium mica ore. The method includes the development of a combined modifier that selectively suppresses gangue minerals and precisely controls the conditions of the ore pulp, as well as a combined collector that purposefully hydrophobizes the iron-lithium mica in the ore. Then, a flotation column is used to pre-concentrate the low-grade iron-lithium mica ore, removing most of the

[0011] gang minerals and reducing the ore volume for subsequent processing. The lithium concentrate obtained from flotation, after defoaming, undergoes fine grinding to completely liberate the iron-lithium mica. High-gradient magnetic separation then re-beneficiates the lithium coarse concentrate, ensuring the effective separation of iron-lithium mica ore and white mica from other gangue minerals. This improves the quality of the lithium concentrate and reduces the proportion of impurities.

[0012] A method for flotation pre-concentration and magnetic separation of low-grade iron-lithium mica ore, the specific steps of which are as follows:

[0013] (1) crushing and coarse grinding of low-grade iron-lithium mica ore, followed by adding clean water to adjust the mass concentration of ore pulp within 28-40%;

[0014] (2) adding a combined modifier and a combined collector to the ore pulp obtained in step (1), followed by carrying out a primary rough enrichment operation in a flotation column, as a result of which a primary rough enrichment concentrate in a flotation column and primary rough enrichment tailings in a flotation column are obtained;

[0015] (3) adding a combined modifier and a combined collector to the primary flotation column rough concentration tailings obtained in step (2), followed by secondary flotation column rough concentration, thereby obtaining a secondary flotation column rough concentration concentrate and secondary flotation column rough concentration tailings; the secondary flotation column rough concentration tailings are flotation tailings;

[0016] (4) combining the primary coarse concentrate obtained in step (2) and the secondary coarse concentrate obtained in step (3) in a flotation column to obtain a coarse-fraction lithium coarse concentrate, followed by pulp preparation, foaming and fine grinding, and adding clean water to adjust the mass concentration of the ore pulp to 10-20%;

[0017] (5) carrying out primary magnetic separation in a high gradient separator of the ore pulp obtained in step (4), to obtain primary magnetic separation concentrate and primary magnetic separation tailings;

[0018] (6) performing secondary magnetic separation in a high gradient separator on the primary magnetic separation tailings obtained in step (5), to obtain a secondary magnetic separation concentrate and secondary magnetic separation tailings; the secondary magnetic separation tailings are magnetic separation tailings;

[0019] (7) combining the primary magnetic separation concentrate obtained in step (5) and the secondary magnetic separation concentrate obtained in step (6) to obtain a collective magnetic separation concentrate; said collective magnetic separation concentrate is lithium concentrate;

[0020] The combination modifier is a mixture of sodium carbonate and sodium hexametaphosphate, and the combination collector is a mixture of lauryl amine acetate, sodium coco-sulfate, di(hydroxyethyl)methyldodecyl ammonium chloride and sodium ethoxylated alkyl sulfate.

[0021] Preferably, in step (1), the mass content of Li2O in the low-grade iron-lithium mica ore is 0.29-0.63%.

[0022] Preferably, in the step (2) of primary rough beneficiation in the flotation column, per one ton of low-grade iron-lithium mica ore, 400-600 g of combined modifier and 380-540 g of combined collector are added to the ore pulp.

[0023] Preferably, in the step (3) of secondary rough enrichment in the flotation column, per one ton of low-grade iron-lithium mica ore, 200-300 g of combined modifier and 190-270 g of combined collector are added to the ore pulp.

[0024] Preferably, on the condition that the mass fraction of the combined modifier is taken as 100%, sodium carbonate accounts for 45-65% in it, and sodium hexametaphosphate accounts for 35-55%.

[0025] Preferably, on the condition that the mass fraction of the combined collector is taken as 100%, lauryl amine acetate accounts for 35-45%, sodium coco-sulfate accounts for 30-40%, di(hydroxyethyl)methyldodecyl ammonium chloride accounts for 5-15%, and sodium ethoxylated alkyl sulfate accounts for 10-20%.

[0026] Preferably, in step (5), the primary magnetic separation is carried out at a magnetic field strength of 1.5-1.7 T.

[0027] Preferably, in step (6), the secondary magnetic separation is carried out at a magnetic field strength of 1.6-1.8 T.

[0028] Beneficial effects of the present invention:

[0029] (1) The present invention is based on a combined technology of two-stage beneficiation by flotation and magnetic separation. It includes optimization of particle size distribution by stage-by-stage grinding, pre-beneficiation of low-grade iron-lithium mica ore in a flotation column, foaming of the resulting lithium coarse concentrate and subsequent fine grinding to ensure complete dissociation of iron-lithium mica, re-beneficiation of the lithium coarse concentrate by high-gradient magnetic separation, which contributes to the effective separation of iron-lithium mica ore from gangue minerals such as white mica, and ultimately improves the quality of the lithium concentrate and reduces the proportion of impurities.

[0030] (2) The combined modifier developed in this invention not only ensures the selective suppression of gangue minerals but also enables precise control of the ore pulp environment. The combined collector ensures targeted hydrophobization of iron-lithium mica in the ore, enabling efficient extraction of iron-lithium mica from the ore in just two stages of rough enrichment in a flotation column. This realizes a synergistic effect between the flotation column and reagents, ensuring the removal of a large portion of gangue minerals and significantly reducing the volume of ore requiring further processing.

[0031] (3) The flotation column pre-beneficiation process proposed in this invention involves only two rough beneficiation cycles without cleaning or scavenging. It does not recycle mid-size fractions, preventing the accumulation and circulation of sludge in the flotation system and eliminating the negative impact of sludge on flotation performance. Using a flotation column as beneficiation equipment prolongs bubble residence time, promotes stable adhesion of microdispersed iron-lithium mica to the bubbles, optimizes the structure of flotation froth and its mineral content, and increases flotation efficiency.

[0032] (4) The use of flotation pre-concentration improves ore grade before magnetic separation while significantly reducing the volume of ore processing at the fine grinding stage, thereby reducing the need for magnetic separation and dehydration equipment and energy consumption. Furthermore, secondary magnetic separation is sufficient to produce high-quality lithium concentrate. Thus, implementing a short process flow diagram ensures efficient extraction of iron-lithium mica across the entire particle size distribution. This economically solves the process problems inherent in traditional methods of processing low-grade iron-lithium mica ore, such as a long process chain, a large number of reagent injection points, significant impact of middle fraction return, process instability, and low recovery rates.

[0033] DESCRIPTION OF DRAWINGS

[0034] Fig. 1 is a flow chart of the present invention.

[0035] SPECIFIC IMPLEMENTATION METHODS

[0036] Below, the present invention is explained using specific implementation methods, but the scope of its protection is not limited to the given content.

[0037] In an embodiment of the present invention, the combined modifier is a mixture of sodium carbonate and sodium hexametaphosphate, and the combined collector is a mixture of lauryl amine acetate, sodium coco-sulfate, di(hydroxyethyl)methyl dodecyl ammonium chloride and ethoxylated sodium alkyl sulfate.

[0038] Embodiment Example 1: In this embodiment, assuming that the mass fraction of the combined modifier is taken as 100%, sodium carbonate accounts for 45%, and sodium hexametaphosphate accounts for 55%; assuming that the mass fraction of the combined collector is taken as 100%, lauryl amine acetate accounts for 35%, sodium coco-sulfate accounts for 40%, di(hydroxyethyl)methyldodecyl ammonium chloride accounts for 15%, and sodium ethoxylated alkyl sulfate accounts for 10%;

[0039] as shown in Fig. 1, a method for flotation pre-concentration and magnetic separation of low-grade iron-lithium mica ore, the specific steps of which are as follows:

[0040] (1) crushing and coarse grinding of low-grade iron-lithium mica ore, then adding clean water to adjust the mass concentration of ore pulp to within 28%; the mass content of Li2O in the low-grade iron-lithium mica ore is 0.29%;

[0041] (2) adding a combined modifier and a combined collector to the ore pulp obtained in step (1), followed by primary rough beneficiation in a flotation column, thereby obtaining a primary rough beneficiation concentrate in a flotation column and primary rough beneficiation tailings in a flotation column; per ton of low-grade iron-lithium mica ore, 400 g of combined modifier and 380 g of combined collector are added to the ore pulp in the primary rough beneficiation in a flotation column;

[0042] (3) adding a combined modifier and a combined collector to the primary flotation column rough concentration tailings obtained in step (2), followed by secondary flotation column rough concentration, thereby obtaining a secondary flotation column rough concentration concentrate and secondary flotation column rough concentration tailings; the secondary flotation column rough concentration tailings are flotation tailings; per ton of low-grade ferrous lithium mica ore, 200g of combined modifier and 190g of combined collector are added to the ore pulp during secondary flotation column rough concentration;

[0043] (4) combining the primary coarse concentrate obtained in step (2) and the secondary coarse concentrate obtained in step (3) in a flotation column to obtain a coarse-fraction lithium coarse concentrate, followed by pulp preparation, foaming and fine grinding, and adding clean water to adjust the mass concentration of the ore pulp to 10%;

[0044] (5) carrying out primary magnetic separation in a high gradient separator of the ore pulp obtained in step (4), to obtain primary magnetic separation concentrate and primary magnetic separation tailings; in this case, magnetic separation during primary enrichment is carried out at a magnetic field strength of 1.5 T;

[0045] (6) performing secondary magnetic separation in a high gradient separator on the primary magnetic separation tailings obtained in step (5), to obtain secondary magnetic separation concentrate and secondary magnetic separation tailings; the secondary magnetic separation tailings are magnetic separation tailings; wherein, magnetic separation in secondary enrichment is carried out at a magnetic field strength of 1.6 T;

[0046] (7) combining the primary magnetic separation concentrate obtained in step (5) and the secondary magnetic separation concentrate obtained in step (6) to obtain a collective magnetic separation concentrate; said collective magnetic separation concentrate is lithium concentrate;

[0047] In this embodiment, the lithium recovery rate in flotation is 82.8%.

[0048] Embodiment Example 2: In this embodiment, assuming that the mass fraction of the combined modifier is taken as 100%, sodium carbonate accounts for 55%, and sodium hexametaphosphate accounts for 45%; assuming that the mass fraction of the combined collector is taken as 100%, lauryl amine acetate accounts for 40%, sodium coco-sulfate accounts for 30%, di(hydroxyethyl)methyldodecyl ammonium chloride accounts for 10%, and sodium ethoxylated alkyl sulfate accounts for 20%;

[0049] as shown in Fig. 1, a method for flotation pre-concentration and magnetic separation of low-grade iron-lithium mica ore, the specific steps of which are as follows:

[0050] (1) crushing and coarse grinding of low-grade iron-lithium mica ore, then adding clean water to adjust the mass concentration of ore pulp to within 34%; the mass content of Li2O in the low-grade iron-lithium mica ore is 0.46%;

[0051] (2) adding a combined modifier and a combined collector to the ore pulp obtained in step (1), followed by primary rough beneficiation in a flotation column, thereby obtaining a primary rough beneficiation concentrate in a flotation column and primary rough beneficiation tailings in a flotation column; per ton of low-grade iron-lithium mica ore, 500 g of a combined modifier and 460 g of a combined collector are added to the ore pulp in the primary rough beneficiation in a flotation column;

[0052] (3) adding a combined modifier and a combined collector to the primary flotation column rough concentration tailings obtained in step (2), followed by secondary flotation column rough concentration, thereby obtaining a secondary flotation column rough concentration concentrate and secondary flotation column rough concentration tailings; the secondary flotation column rough concentration tailings are flotation tailings; per ton of low-grade ferrous lithium mica ore, 250g of combined modifier and 230g of combined collector are added to the ore pulp in the secondary flotation column rough concentration;

[0053] (4) combining the primary coarse concentrate obtained in step (2) and the secondary coarse concentrate obtained in step (3) in a flotation column to obtain a coarse-fraction lithium coarse concentrate, followed by pulp preparation, foaming and fine grinding, and adding clean water to adjust the mass concentration of the ore pulp to 15%;

[0054] (5) carrying out primary magnetic separation in a high gradient separator of the ore pulp obtained in step (4), to obtain primary magnetic separation concentrate and primary magnetic separation tailings; in this case, magnetic separation during primary enrichment is carried out at a magnetic field strength of 1.6 T;

[0055] (6) performing secondary magnetic separation in a high gradient separator on the primary magnetic separation tailings obtained in step (5), to obtain a secondary magnetic separation concentrate and secondary magnetic separation tailings; the secondary magnetic separation tailings are magnetic separation tailings; and the magnetic field strength during secondary magnetic separation is 1.7 T;

[0056] (7) combining the primary magnetic separation concentrate obtained in step (5) and the secondary magnetic separation concentrate obtained in step (6) to obtain a collective magnetic separation concentrate; said collective magnetic separation concentrate is lithium concentrate;

[0057] In this embodiment, the lithium recovery rate in flotation is 84.1%.

[0058] Embodiment Example 3: In this embodiment, assuming that the mass fraction of the combined modifier is taken as 100%, sodium carbonate accounts for 65%, and sodium hexametaphosphate accounts for 35%; assuming that the mass fraction of the combined collector is taken as 100%, lauryl amine acetate accounts for 45%, sodium coco-sulfate accounts for 35%, di(hydroxyethyl)methyldodecyl ammonium chloride accounts for 5%, and sodium ethoxylated alkyl sulfate accounts for 15%;

[0059] as shown in Fig. 1, a method for flotation pre-concentration and magnetic separation of low-grade iron-lithium mica ore, the specific steps of which are as follows:

[0060] (1) crushing and coarse grinding of low-grade iron-lithium mica ore, then adding clean water to adjust the mass concentration of ore pulp to within 40%; the mass content of Li2O in the low-grade iron-lithium mica ore is 0.63%;

[0061] (2) adding a combined modifier and a combined collector to the ore pulp obtained in step (1), followed by primary rough beneficiation in a flotation column, thereby obtaining a primary rough beneficiation concentrate in a flotation column and primary rough beneficiation tailings in a flotation column; per ton of low-grade iron-lithium mica ore, 600 g of combined modifier and 540 g of combined collector are added to the ore pulp in the primary rough beneficiation in a flotation column;

[0062] (3) adding a combined modifier and a combined collector to the primary flotation column rough concentration tailings obtained in step (2), followed by secondary flotation column rough concentration, thereby obtaining a secondary flotation column rough concentration concentrate and secondary flotation column rough concentration tailings; the secondary flotation column rough concentration tailings are flotation tailings; per ton of low-grade ferrous lithium mica ore, 300 g of a combined modifier and 270 g of a combined collector are added to the ore pulp in the secondary flotation column rough concentration;

[0063] (4) combining the primary coarse concentrate obtained in step (2) and the secondary coarse concentrate obtained in step (3) in a flotation column to obtain a coarse-fraction lithium coarse concentrate, followed by pulp preparation, foaming and fine grinding, and adding clean water to adjust the mass concentration of the ore pulp to 20%;

[0064] (5) carrying out primary magnetic separation in a high gradient separator of the ore pulp obtained in step (4), to obtain primary magnetic separation concentrate and primary magnetic separation tailings; in this case, magnetic separation during primary enrichment is carried out at a magnetic field strength of 1.7 T;

[0065] (6) performing secondary magnetic separation in a high gradient separator on the primary magnetic separation tailings obtained in step (5), to obtain a secondary magnetic separation concentrate and secondary magnetic separation tailings; the secondary magnetic separation tailings are magnetic separation tailings; and the magnetic field strength during secondary magnetic separation is 1.8 T;

[0066] (7) combining the primary magnetic separation concentrate obtained in step (5) and the secondary magnetic separation concentrate obtained in step (6) to obtain a collective magnetic separation concentrate; said collective magnetic separation concentrate is lithium concentrate;

[0067] In this embodiment, the lithium recovery rate in flotation is 85.5%.

[0068] The specific embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments, and various modifications can be made within the scope of knowledge available to those skilled in the art without departing from the spirit of the present invention.

Claims

1. A method for flotation pre-enrichment and magnetic separation of low-grade iron-lithium mica ore, which includes the following stages: (1) crushing and coarse grinding of low-grade iron-lithium mica ore, followed by adding clean water to regulate the mass concentration of ore pulp within 28-40%; (2) adding a combined modifier and a combined collector to the ore pulp obtained in step (1), followed by carrying out a primary rough enrichment operation in a flotation column, as a result of which a primary rough enrichment concentrate in a flotation column and primary rough enrichment tailings in a flotation column are obtained; (3) adding a combined modifier and a combined collector to the primary coarse enrichment tailings in a flotation column obtained in step (2), followed by secondary coarse enrichment in a flotation column, as a result of which a secondary coarse enrichment concentrate in a flotation column and secondary coarse enrichment tailings in a flotation column are obtained; the secondary coarse enrichment tailings in a flotation column are flotation tailings; (4) combining the primary coarse concentrate in a flotation column obtained in step (2) and the secondary coarse concentrate in a flotation column obtained in step (3) to obtain a coarse-fraction lithium coarse concentrate, followed by pulp preparation, foam suppression and fine grinding, and the addition of clean water to regulate the mass concentration of the ore pulp to 10-20%; (5) carrying out primary magnetic separation in a high gradient separator of the ore pulp obtained in stage (4), to obtain primary magnetic separation concentrate and primary magnetic separation tailings; (6) carrying out secondary magnetic separation in a high gradient separator of the primary magnetic separation tailings obtained in step (5) to obtain a secondary magnetic separation concentrate and secondary magnetic separation tailings; the secondary magnetic separation tailings are magnetic separation tailings; (7) combining the primary magnetic separation concentrate obtained in step (5) and the secondary magnetic separation concentrate obtained in step (6) to obtain a bulk magnetic separation concentrate; said bulk magnetic separation concentrate is a lithium concentrate; The combined modifier is a mixture of sodium carbonate and sodium hexametaphosphate, and the combined collector is a mixture of lauryl amine acetate, sodium coco-sulfate, di(hydroxyethyl)methyldodecyl ammonium chloride and sodium ethoxylated alkyl sulfate.

2. The method according to claim 1, characterized in that at step (1) the mass content of Li2O in the low-grade iron-lithium mica ore is 0.29-0.63%.

3. The method according to paragraph 1, characterized in that at stage (2) of primary rough enrichment in a flotation column, per one ton of low-grade iron-lithium mica ore, 400-600 g of combined modifier and 380-540 g of combined collector are added to the ore pulp.

4. The method according to paragraph 1, characterized in that at stage (3) of secondary rough enrichment in a flotation column, per one ton of low-grade iron-lithium mica ore, 200-300 g of combined modifier and 190-270 g of combined collector are added to the ore pulp.

5. The method according to paragraph 1, characterized in that, provided that the mass fraction of the combined modifier is taken as 100%, sodium carbonate makes up 45-65% of it, and sodium hexametaphosphate - 35-55%.

6. The method according to claim 1, characterized in that, provided that the mass fraction of the combined collector is taken as 100%, lauryl amine acetate makes up 35-45%, sodium cocosulfate - 30-40%, di(hydroxyethyl)methyldodecyl ammonium chloride - 5-15%, and ethoxylated sodium alkyl sulfate - 10-20%.

7. The method according to paragraph 1, characterized in that at stage (5) the primary magnetic separation is carried out at a magnetic field strength of 1.5-1.7 T.

8. The method according to paragraph 1, characterized in that at stage (6) the secondary magnetic separation is carried out at a magnetic field strength of 1.6-1.8 T.

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