A flotation method and flotation reagent suitable for high-ash fine-grained difficult-to-float coal slime

Abstract

The present invention provides a flotation method and a flotation agent applicable to high-ash fine-grained difficult-to-float coal slime, belonging to the technical field of mineral processing. The flotation agent comprises a first collector, a second collector and a foaming agent; wherein the first collector is composed of dodecane and n-pentanoic acid; the second collector is composed of fatty alcohol polyoxyethylene ether, oleic acid diethanolamide, dodecane, n-pentanoic acid, nonylphenol polyoxyethylene ether, amyl benzoate and amino acid type sodium coconut oil glycolate; the foaming agent is methyl isobutyl carbinol. The flotation method and the flotation agent can well enhance the flotation effect of high-ash fine-grained difficult-to-float coal slime.

Description

Technical Field

[0001] The invention belongs to the technical field of mineral processing, and in particular relates to a flotation method and a flotation reagent suitable for high-ash fine-grained difficult-to-float coal slime. Background Art

[0002] In the coal processing industry, flotation technology is a commonly used method for separating and purifying coal slime. However, for high-ash, fine-grained, difficult-to-float coal slime, traditional flotation methods and flotation reagents often have certain challenges. Since high-ash, fine-grained, difficult-to-float coal slime usually contains a large amount of ash and fine-grained gangue minerals, it is difficult for traditional flotation methods and flotation reagents to effectively separate and purify it.

[0003] Specifically, the flotation separation of high-ash, fine-grained, difficult-to-float coal slime currently has the following difficulties: (1) The ash content of the coal slime entering the flotation chamber increases sharply, and the high-ash fine slime is easy to contaminate the clean coal product through covering, entrainment, and carrying; (2) The high-ash fine slime is mainly composed of a large amount of fine-grained gangue minerals mixed in the coal particles, and its specific surface area is large, the flotation selectivity is poor, and a large amount of reagents are consumed in the traditional flotation process. The above factors lead to low flotation recovery rate of high-ash, fine-grained, difficult-to-float coal slime and serious fluctuations in the quality of clean coal products, which restricts the efficient flotation of coal slime.

[0004] Therefore, in view of the characteristics of high-ash, fine-grained, difficult-to-float coal slime, suitable flotation reagents should have the following characteristics: (1) Improve the separation effect of specific impurities based on the characteristics of coal slime. (2) Consider the particle characteristics and flotation conditions of coal slime and optimize the ratio and use of reagents. (3) Combined with advanced flotation equipment and control systems, accurate flotation separation of coal slime can be achieved. In addition, how to provide a flotation method that can be applied to high-ash, fine-grained, difficult-to-float coal slime is also a problem that needs to be solved in this field. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems in the related art to a certain extent. To this end, the embodiments of the present invention provide a flotation method and flotation reagent suitable for high-ash fine-particle difficult-to-float coal slime, which can effectively solve the problems of increased ash content of the floating coal slime, easy contamination of clean coal by high-ash fine slime, and deterioration of the flotation effect, and realize efficient separation of high-ash fine-particle difficult-to-float coal slime.

[0006] A first aspect of an embodiment of the present invention provides a flotation agent suitable for high-ash, fine-particle, difficult-to-float coal slime, comprising a first collector, a second collector and a frother; wherein the first collector is composed of dodecane and n-pentanoic acid; the second collector is composed of fatty alcohol polyoxyethylene ether, oleic acid diethanolamide, dodecane, n-pentanoic acid, nonylphenol polyoxyethylene ether, amyl benzoate and amino acid type sodium coconut glycolate; the frother is methyl isobutyl carbinol.

[0007] The advantages and technical effects brought by the flotation reagent of the first aspect of the embodiment of the present invention are:

[0008] The flotation reagent of the first aspect of the embodiment of the present invention effectively solves the problem of difficulty in flotation of high-ash fine-particle difficult-to-float coal slime, and achieves maximum recovery of coal resources while ensuring product quality.

[0009] In some embodiments, in the first collector, the mass ratio of the dodecane to the n-pentanoic acid is (0.5-3.0): (0.5-3.0).

[0010] In some embodiments, in the second collector, the mass ratio of the fatty alcohol polyoxyethylene ether, the oleic acid diethanolamide, the dodecane, the n-valeric acid, the nonylphenol polyoxyethylene ether, the amyl benzoate and the amino acid type sodium coconut glycolate is (0.6~1.0):(3.0~5.0):(5.0~8.0):(5~8.0):(0.6~1.0):(0.5~1.5):(0.1~0.3).

[0011] A second aspect of the embodiment of the present invention provides a flotation method applicable to high-ash fine-particle difficult-to-float coal slime, using the flotation reagent of the first aspect of the embodiment of the present invention, and the flotation method comprises the following steps:

[0012] S1, mechanically stirring and slurrying the coal slime, adding the first collector during the mechanical stirring and slurrying process to obtain a first slurrying slurry;

[0013] S2, passing the slurry after the first slurry adjustment into a first flotation machine for first flotation, and sequentially adding the second collector and the frother during the first flotation process to obtain first flotation clean coal and first flotation tail coal;

[0014] S3, passing the first flotation clean coal into a secondary flotation machine for second flotation, adding the second collector during the second flotation process to obtain second flotation clean coal and second flotation tail coal;

[0015] S4, subjecting the second flotation clean coal to high-speed shearing slurry adjustment, and adding the first collector during the high-speed shearing slurry adjustment process to obtain a second slurry adjustment slurry;

[0016] S5, passing the slurry after the second slurry adjustment into a third-selection flotation machine for third flotation, adding the frother during the third flotation process to obtain third flotation clean coal and third flotation tail coal;

[0017] S6, measuring the ash content of the third flotation clean coal, if the ash content of the third flotation clean coal meets the standard, the third flotation clean coal is directly used as the clean coal product, the second flotation tail coal and the third flotation tail coal are used as the medium coal product, and the first flotation tail coal is used as the tail coal product, and is subjected to concentration, sedimentation and filtration treatment;

[0018] If the ash content of the clean coal from the third flotation does not meet the standard, the clean coal from the third flotation is passed into the fourth flotation machine for the fourth flotation, and the frother is added during the fourth flotation process to obtain the fourth flotation clean coal and the fourth flotation tail coal. If the ash content of the clean coal from the fourth flotation meets the standard, the fourth flotation clean coal is used as the clean coal product, the second flotation tail coal, the third flotation tail coal and the fourth flotation tail coal are used as medium coal products, and the first flotation tail coal is used as the tail coal product, and is subjected to concentration, sedimentation and filtration treatment.

[0019] The advantages and technical effects brought by the flotation method of the second aspect of the embodiment of the present invention are:

[0020] The flotation method of the second aspect of the embodiment of the present invention effectively solves the problem of difficulty in flotation of high-ash, fine-particle, difficult-to-float coal slime, achieves maximum recovery of coal resources while ensuring product quality, and achieves effective separation of coal slime with characteristics such as high-ash, fine-particle, and difficult-to-float through the method of mechanical stirring slurry adjustment + first flotation + second flotation + high-speed shear slurry adjustment + third flotation and optionally fourth flotation + precise matching and addition of reagents.

[0021] In some embodiments, in step S1, the concentration of the slurry after the first slurry adjustment is 80-100 g / L; and / or, the rotation speed of the mechanical stirring slurry adjustment is 1200-1500 r / min; and / or, the time of the mechanical stirring slurry adjustment is 2-6 min; and / or, the amount of the first collector added during the mechanical stirring slurry adjustment is 0.5-1.5 kg / t 干煤泥 .

[0022] In some embodiments, in step S2, the amount of the second collector added during the first flotation process is 0.5-3 kg / t 干煤泥 ; and / or, the amount of the frother added during the first flotation process is 0.2~1kg / t 干煤泥 .

[0023] In some embodiments, in step S3, the amount of the second collector added during the second flotation process is 0.5-2.0 kg / t 干煤泥 .

[0024] In some embodiments, in step S4, the concentration of the slurry after the second slurry adjustment is 40-60 g / L; and / or the rotation speed of the high-speed shear slurry adjustment is 1900-2100 r / min; and / or the time of the high-speed shear slurry adjustment is 4-8 min; and / or the amount of the first collector added during the high-speed shear slurry adjustment is 1 / 10-1 / 7 of the amount of the second collector added during the first flotation process.

[0025] In some embodiments, in step S5, the amount of the frother added in the third flotation process is 0.01-0.04 kg / t 干煤泥 .

[0026] In some embodiments, in steps S1 to S5, the first collector is added in a staged addition manner; and / or, the second collector is added in a staged addition manner; and / or, the foaming agent is added in a staged addition manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a process flow chart of the flotation method of Examples 1-2. DETAILED DESCRIPTION

[0028] Embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention.

[0029] A first aspect of an embodiment of the present invention provides a flotation agent suitable for high-ash, fine-grained, difficult-to-float coal slime, comprising a first collector, a second collector and a frother; wherein the first collector is composed of dodecane and n-pentanoic acid; the second collector is composed of fatty alcohol polyoxyethylene ether, oleic acid diethanolamide, dodecane, n-pentanoic acid, nonylphenol polyoxyethylene ether, amyl benzoate and amino acid type sodium coconut glycolate; and the frother is methyl isobutyl carbinol.

[0030] Working principle: The organic components in coal mainly refer to various organic compounds contained in coal. These compounds are mainly composed of elements such as carbon, hydrogen, oxygen, and nitrogen, including but not limited to: aromatic hydrocarbons: such as benzene, naphthalene, etc. These compounds have high stability and carbon content; aliphatic hydrocarbons: including chain hydrocarbons and cyclic hydrocarbons, which are easier to burn and provide coal with combustibility; phenolic compounds: such as phenol, naphthyl alcohol, etc. These compounds have strong hydrophilicity; nitrogen-containing compounds, etc.

[0031] The first collector is composed of dodecane and n-pentanoic acid. Dodecane is a non-polar component and can act on the hydrophobic sites of the organic components on the surface of low-rank coal to enhance the hydrophobicity of the low-rank coal. n-pentanoic acid is a polar component. The carboxyl group in n-pentanoic acid can act on the hydrophilic sites of the organic components on the surface of low-rank coal (such as the hydrogen bonds of the oxygen-containing groups on the coal surface) to enhance the hydrophobicity of the low-rank coal.

[0032] The second collector is composed of fatty alcohol polyoxyethylene ether (AEO9), oleic acid diethanolamide (ODEA), dodecane, n-pentanoic acid, nonylphenol polyoxyethylene ether (NP10), amyl benzoate and amino acid type sodium cocoyl glycolate (SCG). Among them, non-ionic surfactants such as fatty alcohol polyoxyethylene ether, oleic acid diethanolamide, nonylphenol polyoxyethylene ether and coal surface groups can form hydrogen bonds, expose hydrophobic hydrocarbon chains, and enhance the hydrophobicity of low-rank coal. SCG is an anionic surfactant that can effectively reduce the surface tension of coal particles and improve the flotation of coal particles. The long-chain coconut oil-based structure in SCG is a derivative of coconut oil, which can usually improve the wettability and surface activity of SCG and further enhance the adhesion of the second collector on the surface of coal particles. At the same time, the long-chain coconut oil-based structure in SCG has a strong repulsive effect on water, which can make the surface of coal particles more hydrophobic, thereby improving the affinity between coal particles and bubbles during flotation. Moreover, SCG has an amino acid structure, which enables SCG to selectively adsorb on the surface of coal particles, which helps to improve the flotation selectivity of coal particles and reduce the interference of other minerals. Amyl benzoate molecules can enhance the hydrophobicity of the surface of low-rank coal by adsorbing on the hydrophilic sites on the surface of low-rank coal. The carboxyl group in valeric acid can enhance the hydrophobicity of the surface of low-rank coal by hydrogen bonding with the oxygen-containing groups on the surface of coal particles. Dodecane can enhance the hydrophobicity of low-rank coal through synergistic effects with amyl benzoate and valeric acid.

[0033] Therefore, the first collector can enhance the hydrophobicity of the organic components on the surface of coal particles, so that the organic components in the pulp will agglomerate. The agglomeration of organic components can agglomerate coal particles and increase the size of coal particles, making coal particles more easily combined with bubbles, thereby improving flotation efficiency. The second collector can enhance the hydrophobicity of the organic components on the surface of coal particles, so that the organic components in the pulp will agglomerate, so that the coal particles will agglomerate, increase the size of coal particles, making coal particles more easily combined with bubbles, thereby improving flotation efficiency. More importantly, the second collector has high capture and specific sorting characteristics. The second collector can selectively adsorb on the surface of coal particles, which helps to improve the flotation selectivity of the target mineral and reduce the interference of other minerals.

[0034] The role of the frother is to promote the formation and stability of foam, so that the clean coal is better separated from impurities such as gangue, thereby improving the recovery rate and quality of the clean coal. In the flotation reagent of the first aspect of the embodiment of the present invention, the frother is methyl isobutyl carbinol (MIBC). This frother can produce small and dense bubbles, which is conducive to more coal particles adhering to the surface of the bubbles and floating, so as to achieve the purpose of improving the flotation efficiency. The bubbles produced by other types of frothers are relatively large, resulting in poor flotation efficiency.

[0035] In some embodiments, in the first collector, the mass ratio of dodecane and n-pentanoic acid is (0.5~3.0): (0.5~3.0), for example, 6:1, 5:1, 4:1, 3:1, 2:1, 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, etc. When the mass ratio of the components of the first collector is within the above range, it is beneficial to improve the hydrophobicity of low-rank coal, thereby facilitating the efficient separation of high-ash fine particles and difficult-to-float coal slime. When the mass ratio of dodecane and n-pentanoic acid in the first collector is too small, it is not conducive to improving the selectivity of the first collector and the separation effect on coal particles. When the mass ratio of dodecane and n-pentanoic acid in the first collector is too large, it is not conducive to improving the balance of the first collector and the separation effect on coal particles.

[0036] In some embodiments, in the second collector, the mass ratio of fatty alcohol polyoxyethylene ether, oleic acid diethanolamide, dodecane, n-pentanoic acid, nonylphenol polyoxyethylene ether, amyl benzoate and amino acid type sodium cocoyl glycolate is (0.6-1.0): (3.0-5.0): (5.0-8.0): (5-8.0): (0.6-1.0): (0.5-1.5): (0.1-0.3). When the mass ratio of each component of the second collector is within the above range, the second collector is an agent with high capture and specific separation, thereby achieving efficient separation of high-ash fine-grained difficult-to-float coal slime.

[0037] In some embodiments, the preparation method of the second collector may include the following steps: ① placing fatty alcohol polyoxyethylene ether, oleic acid diethanolamide, dodecane, n-pentanoic acid, nonylphenol polyoxyethylene ether, amyl benzoate and amino acid type sodium cocoyl glycolate in a container in a ratio of (0.6~1.0): (3.0~5.0): (5.0~8.0): (5~8): (0.6~1.0): (0.5~1.5): (0.1~0.3) to obtain a mixture; ② using an electric stirrer to pre-mix the above mixture, the stirring speed may be 500~800 r / min, the stirring time may be 10~15 min, to obtain a premix; ③ optionally, in order to make the dispersion of the components in the second collector more uniform and make the second collector easier to act on the surface of coal particles, the second collector may be subjected to ultrasonic treatment, and an ultrasonic head is inserted into the container for ultrasonic treatment, the ultrasonic frequency may be 20~25 KHz, and the ultrasonic treatment time may be 10~15 min, and after ultrasound, the second collector becomes a colloidal solution.

[0038] A second aspect of the embodiment of the present invention provides a flotation method applicable to high-ash fine-particle difficult-to-float coal slime, using the flotation reagent of the first aspect of the embodiment of the present invention, and the flotation method comprises the following steps:

[0039] S1, mechanically stirring and slurrying the coal slime, adding a first collector during the mechanical stirring and slurrying process to obtain a first slurrying slurry;

[0040] S2, passing the slurry after the first slurry adjustment into a first flotation machine for first flotation, and sequentially adding a second collector and a frother during the first flotation process to obtain first flotation clean coal and first flotation tail coal;

[0041] S3, passing the first flotation clean coal into the second flotation machine for second flotation, adding the second collector during the second flotation process to obtain the second flotation clean coal and the second flotation tail coal;

[0042] S4, subjecting the secondary flotation clean coal to high-speed shearing slurry adjustment, and adding the first collector during the high-speed shearing slurry adjustment process to obtain the slurry after the second slurry adjustment;

[0043] S5, passing the slurry after the second slurry adjustment into the third flotation machine for the third flotation, adding a frother during the third flotation process to obtain the third flotation clean coal and the third flotation tail coal;

[0044] S6. Determine the ash content of the third flotation clean coal. If the ash content of the third flotation clean coal meets the standard, the third flotation clean coal is directly used as the clean coal product, the second flotation tail coal and the third flotation tail coal are used as the medium coal product, and the first flotation tail coal is used as the tail coal product for concentration, sedimentation and filtration treatment;

[0045] If the ash content of the clean coal from the third flotation does not meet the standard, the clean coal from the third flotation will be passed into the fourth flotation machine for the fourth flotation. During the fourth flotation, a frother will be added to obtain the fourth flotation clean coal and the fourth flotation tail coal. If the ash content of the clean coal from the fourth flotation meets the standard, the fourth flotation clean coal will be blended into the clean coal product, the second flotation tail coal, the third flotation tail coal and the fourth flotation tail coal will be blended into the medium coal product, and the first flotation tail coal will be used as the tail coal product for concentration, sedimentation and filtration treatment.

[0046] Working principle: In the flotation method of the second aspect of the embodiment of the present invention, step S1 emulsifies and mixes the flotation agent by mechanical stirring, so that the flotation agent can be fully mixed with the slurry, and the slurry can exist in a suspended state, which is conducive to subsequent flotation. The purpose of the first flotation in step S2 is to discard high-ash fine mud as much as possible, for example, the ash content of the tail coal of the first flotation can be higher than 70%. The purpose of the second flotation in step S3 is to be able to increase the yield of flotation clean coal and reduce the ash content of clean coal to a large extent, for example, the ash content of the tail coal of the second flotation can be higher than 75%. The purpose of high-speed shearing slurry adjustment in step S4 is to enhance the selectivity of the subsequent third flotation. The purpose of the third flotation in step S5 is to further increase the yield of flotation clean coal and reduce the ash content of clean coal, so that the ash content of clean coal meets the standard, for example, the ash content of clean coal is less than or equal to 12%. Step S6 determines whether to perform the fourth flotation based on whether the ash content of the clean coal in the third flotation meets the standard.

[0047] In the flotation method of the second aspect of the embodiment of the present invention, the types of collectors added in steps S1 to S4 are not all first collectors or all second collectors, but the first collectors or second collectors are selectively added at different stages for the following reasons:

[0048] First, different collectors have different selectivities for different types of minerals. During the flotation process, different collectors may need to be selected according to the properties of the minerals and the target separation effect. The main function of the first collector is to agglomerate the organic components in the pulp. The second collector has high capture and specific separation, and its main function is to selectively adsorb on the surface of a specific mineral, which helps to improve the flotation selectivity of the target mineral and reduce the interference of other minerals. During the flotation process, the properties of the mineral surface may change. For example, as flotation proceeds, the mineral surface may become more hydrophobic or hydrophilic. The first collector may react better with the mineral surface in the initial stage, while the second collector is more effective in changing the surface state of the mineral in the subsequent stage. Moreover, the pH value, temperature and other conditions during the flotation process may change, and different collectors may show different effects under different conditions. Therefore, the use of different collectors can optimize the flotation effect under different conditions. Therefore, according to the method of the second aspect of the embodiment of the present invention, the first collector or the second collector is selectively added at different flotation stages, and their combination can produce a synergistic effect, which can effectively enhance the overall effect of the flotation process.

[0049] If only the first collector or only the second collector is added throughout the flotation process, it will not play the role of improving flotation selectivity and flotation efficiency as mentioned above when used in combination. In addition, using different collectors in different steps can help control the dosage and cost of the reagents. Although the second collector has a better specific adsorption effect on coal particles, making flotation more efficient, the cost of the second flotation agent is higher than that of the first flotation agent, so using it in the corresponding steps instead of using it in steps S1 to S4 can reduce the overall dosage and cost of flotation reagents.

[0050] In some embodiments, in step S1, the concentration of the slurry after the first slurry adjustment is 80-100 g / L, such as 80 g / L, 85 g / L, 90 g / L, 95 g / L, 100 g / L, etc.; and / or, the rotation speed of the mechanical stirring slurry adjustment is 1200-1500 r / min, such as 1200 r / min, 1250 r / min, 1300 r / min, 1350 r / min, 1400 r / min, 1450 r / min, 1500 r / min, etc.; and / or, the time of mechanical stirring slurry adjustment is 2-6 min, such as 2 min, 3 min, 4 min, 5 min, 6 min, etc. The first collector can be emulsified and mixed by mechanical stirring, so that the first collector can be fully mixed with the slurry, and the slurry can be in a suspended state, which is beneficial to subsequent flotation. The slurry concentration, slurry adjustment speed, slurry adjustment time and / or the dosage of the first collector meeting the above conditions are beneficial to improving the flotation effect.

[0051] In some embodiments, in step S1, the amount of the first collector added during the mechanical stirring slurry mixing process is 0.5-1.5 kg / t 干煤泥 , for example 0.5kg / t 干煤泥 、0.6kg / t 干煤泥 、0.8kg / t 干煤泥 , 1kg / t 干煤泥 , 1.2kg / t 干煤泥 , 1.4kg / t 干煤泥 、1.5kg / t 干煤泥 When the amount of the first collector added during the mechanical agitation and slurry mixing process is too small, it is not conducive to enhancing the hydrophobicity of low-rank coal, and thus is not conducive to improving flotation efficiency. When the amount of the first collector added during the mechanical agitation and slurry mixing process is too large, it is not conducive to reducing costs and increasing efficiency. Specifically, the amount of the first collector can be adjusted according to the floatability of the coal slime.

[0052] In some embodiments, in step S2, the amount of the second collector added during the first flotation process is 0.5-3 kg / t 干煤泥 , for example 0.5kg / t 干煤泥 , 1kg / t 干煤泥 、1.5kg / t 干煤泥 , 2kg / t 干煤泥 , 2.5kg / t 干煤泥 、3kg / t 干煤泥 etc.; and / or, the amount of frother added in the first flotation process is 0.2~1 kg / t 干煤泥 , for example 0.2kg / t 干煤泥 、0.4kg / t 干煤泥 、0.6kg / t 干煤泥 、0.8kg / t 干煤泥 , 1kg / t 干煤泥 Etc. Specifically, the dosage of the second collector can be adjusted according to the floatability of the coal slime, and the dosage of the frother can be adjusted according to the condition of the pulp foam layer. By meeting the above dosage of the second collector and frother, the coal particles and the gangue minerals can be efficiently separated through the first flotation, so that the high-ash fine mud part in the floating material enters the first flotation tailings, thereby achieving the purpose of discarding the high-ash fine mud part of the clean coal as much as possible.

[0053] In some embodiments, in step S3, the amount of the second collector added during the second flotation process is 0.5-2.0 kg / t 干煤泥 , for example 0.5kg / t 干煤泥 、0.6kg / t 干煤泥 、0.8kg / t 干煤泥 , 1kg / t 干煤泥 , 1.2kg / t 干煤泥, 1.4kg / t 干煤泥 、1.6kg / t 干煤泥 、1.8kg / t 干煤泥 , 2.0kg / t 干煤泥 Etc. Specifically, the dosage of the second collector can be adjusted according to the floatability of the coal slime. As for the timing of adding the second collector, for example, the second collector can be added when the scraping time is 74-76s during the second flotation process. For coal slimes of different coal qualities, the scraping time during the flotation process is regulated according to the quality of the clean coal on site. Specifically, the scraping time needs to be determined by observing multiple factors such as the scraping color and the clean coal yield. The actual scraping time varies with the coal quality.

[0054] In some embodiments, in step S4, the concentration of the slurry after the second slurry adjustment is 40-60 g / L; and / or the rotation speed of the high-speed shear slurry adjustment is 1900-2100 r / min; and / or the time of the high-speed shear slurry adjustment is 4-8 min; and / or the amount of the first collector added during the high-speed shear slurry adjustment is 1 / 10-1 / 7 of the amount of the second collector added during the first flotation process.

[0055] In some embodiments, in step S5, the first collector and the second collector are no longer added during the third flotation process.

[0056] In some embodiments, in step S5, the amount of frother added in the third flotation process is 0.01-0.04 kg / t 干煤泥 It is known from engineering practice that for difficult-to-float coal slime with rich surface oxygen-containing functional groups, after the first two flotation steps, the slurry often has a poor foam layer state, so a small amount of frother needs to be added in step S5 according to the foam state.

[0057] In some embodiments, in step S5, the clean coal ash content meets the standard, and the standard requirement here is determined according to customer requirements, for example, it can be less than or equal to 12.00%, or less than or equal to 11.00%, or less than or equal to 10.00%, etc.

[0058] In some embodiments, in steps S1 to S5, the first collector is added in a segmented manner; and / or, the second collector is added in a segmented manner; and / or, the frother is added in a segmented manner. For coal slimes of different coal qualities, by adjusting the addition method of the reagent, different from the one-time addition, the segmented addition is more conducive to controlling and adjusting the flotation speed, ensuring the quality of clean coal, improving the clean coal yield, effectively exerting the role of the reagent, and reducing the consumption of the reagent.

[0059] It is understandable that in step S6, if the ash content of the third flotation clean coal does not meet the standard, it is necessary to continue flotation to meet customer needs. As for the number of flotations after the third flotation, it depends on the actual customer needs and coal quality. For example, the fourth flotation is performed. Optionally, the fifth flotation, the sixth flotation, etc. can also be performed after step S6.

[0060] The present invention is described in detail below with reference to the embodiments and the accompanying drawings.

[0061] Comparative Example 1

[0062] The coal type selected by a coal preparation plant in Huaibei, Anhui (Coal Preparation Plant A) is coking coal (1 / 3 coking coal). However, the coal slime entering the flotation process has the characteristics of high ash and fine particles that are difficult to float. At present, the coal preparation plant still uses relatively traditional flotation technology and flotation agents, which causes a large amount of high ash fine slime to enter the flotation clean coal through carrying and entrainment, causing serious pollution of the clean coal products of the coal preparation plant and affecting the improvement of economic benefits.

[0063] Through the flotation research of Coal Preparation Plant A, it was found that the raw coal ash content of Coal Preparation Plant A was 38.06%, and the fine particle content (<-0.75μm) was as high as 51.27%. The current flotation process of Coal Preparation Plant A is:

[0064] (1) First, a slurry preparation device was used to prepare the floating coal slime. The slurry preparation speed was 1400 r / min, the slurry preparation time was 7 min, and the slurry concentration was adjusted to 80 g / L to obtain the slurry after the first slurry preparation.

[0065] (2) The slurry after the first slurry adjustment is then passed into the first flotation machine for the first flotation. During the first flotation, conventional flotation reagents are added, among which the collector is kerosene, and the kerosene dosage is 4.0 kg / t. 干煤泥 , the foaming agent is 2-octanol, and the dosage of 2-octanol is 0.6 kg / t 干煤泥 , and obtain the first flotation clean coal and the first flotation tailings coal.

[0066] (3) The first flotation clean coal is sent to the second flotation machine for the second flotation. During the second flotation, a small amount of kerosene and 2-octanol is added. The amount of kerosene added is 0.5 kg / t. 干煤泥 , the amount of 2-octanol added is 0.1 kg / t 干煤泥 , and obtain the second flotation clean coal and the second flotation tailings coal.

[0067] (4) The clean coal from the second flotation is sent to the third flotation machine for the third flotation. During the third flotation, a small amount of collector kerosene is added. The amount of kerosene added is 0.4 kg / t. 干煤泥After the third flotation is completed, the third flotation clean coal and the third flotation tail coal are obtained. The yield of the third flotation clean coal is 30.31%, and the ash content of the third flotation clean coal is 12.52%.

[0068] (5) The third flotation clean coal is sent to the fourth flotation machine for the fourth flotation. During the fourth flotation, a small amount of collector kerosene is added. The amount of kerosene added is 0.4 kg / t. 干煤泥 After the fourth flotation is completed, the fourth flotation clean coal and the fourth flotation tailings coal are obtained.

[0069] The tail coal of the fourth flotation is used as the clean coal product, the tail coal of the first flotation, the tail coal of the second flotation, and the tail coal of the third flotation are used as the medium coal product, and the tail coal of the fourth flotation is used as the tail coal product. The yield of the clean coal product is about 20%, and the ash content of the clean coal product is less than 11%. It can be seen that when the ash content of the clean coal meets the requirements (the ash content is less than 11%), the clean coal yield is only about 20%, resulting in a great waste of resources.

[0070] Example 1

[0071] The flotation method and flotation reagent provided by the present invention are used to separate the floating coal slime of A coal preparation plant, such as Figure 1 As shown, the specific steps are as follows:

[0072] (1) First, a stirrer is used to mechanically stir and slurry the floating coal slime. The slurry concentration is adjusted to 80 g / L. The first collector is added during the slurry mixing process. The first collector is a compound of dodecane and n-pentanoic acid in a mass ratio of 1:1. The dosage of the first collector is 1.0 kg / t 干煤泥 The slurry mixing speed was set to 1300 r / min, the slurry mixing time was 5 min, and the slurry after the first slurry mixing was obtained.

[0073] (2) The slurry after the first slurry adjustment is then passed into the first flotation machine for the first flotation. The purpose of the first flotation is to remove the high-ash fine mud as much as possible. The second collector and frother are added during the first flotation. The composition and preparation method of the second collector are as follows. The dosage of the second collector is 1.5 kg / t 干煤泥 MIBC is used as the foaming agent, and the amount of MIBC is 0.35 kg / t 干煤泥 , and obtain the first flotation clean coal and the first flotation tailings coal.

[0074] The second collector is a reagent with high capture and specific sorting. The specific preparation method is as follows: ① Place 1 part of fatty alcohol polyoxyethylene ether AEO9, 5 parts of oleic acid diethanolamide ODEA, 7 parts of dodecane, 7 parts of n-pentanoic acid, 1 part of nonylphenol polyoxyethylene ether NP10, 2 parts of amyl benzoate, and 0.2 parts of amino acid type sodium cocoyl glycolate in a container; ② Use an electric stirrer to pre-mix the above samples at a stirring speed of 500 r / min and a stirring time of 12 min to obtain a mixture. ③ Ultrasonicate the mixture, insert the ultrasonic head into the container for ultrasonic treatment, the ultrasonic frequency is 20 KHz, and the ultrasonic treatment time is 10 minutes to obtain the second collector.

[0075] (3) The first flotation clean coal is passed into the second flotation machine for the second flotation. When the scraping time is 75s, the second collector is added. The dosage of the second collector is 1.0 kg / t. 干煤泥 , and obtain the second flotation clean coal and the second flotation tailings coal.

[0076] (4) The second flotation clean coal is subjected to a high-speed shearing slurry adjustment. The slurry concentration is adjusted to 60 g / L during the slurry adjustment. A small amount of the first collector is added during the slurry adjustment. The amount of the first collector added is 0.15 kg / t. 干煤泥 The slurry adjustment speed was set to 2100 r / min, the slurry adjustment time was 4 min, and the slurry after the second slurry adjustment was obtained.

[0077] (5) The slurry after the second slurry adjustment is passed into the third flotation machine for the third flotation. At this time, the frother MIBC is added. The amount of MIBC is 0.02 kg / t 干煤泥 , and obtain the third flotation clean coal and the third flotation tailings coal.

[0078] (6) After the third flotation, the ash content of the third flotation clean coal is measured. Generally, the ash content of the third flotation clean coal is less than 11%, which has reached the standard. However, due to the influence of factors such as underground mining faults, coal quality fluctuations, coal quality characteristics and flotation equipment parameters, the third flotation clean coal occasionally has an ash content that does not meet the standard (ash content > 11%). At this time, it is necessary to further measure the ash content of the clean coal in each flotation chamber of the third flotation machine, and the part that does not meet the ash content standard will be subjected to the fourth flotation. During the fourth flotation, no collector is added, but a small amount of MIBC is added. The amount of MIBC is 0.01 kg / t 干煤泥 , and obtain the fourth flotation clean coal and the fourth flotation tailings coal.

[0079] After the fourth flotation, the ash content of the fourth flotation clean coal was measured. If the ash content reached the standard (less than 11%), the fourth flotation clean coal was blended into the clean coal product, the second flotation tail coal, the third flotation tail coal and the fourth flotation tail coal were blended into the medium coal product, and the first flotation tail coal was used as the tail coal product for concentration, sedimentation and filtration. The yield of the clean coal product was 55.21%, and the ash content of the clean coal product was 10.41%.

[0080] Comparative Example 2

[0081] The type of coal selected by a coal preparation plant in Shanxi (B Coal Preparation Plant) is lignite. The coal slime entering flotation has the characteristics of high ash and fine mud content, and flotation separation is difficult. For many years, a large amount of coal slime has been directly mixed with tailings for sale without separation and quality improvement, resulting in a huge waste of coal resources.

[0082] Through the flotation research of B coal preparation plant, it was found that the raw coal ash of B coal preparation plant was 34.25%, and the fine particle content (<-0.75μm) (that is, the proportion of particles with a particle size less than -0.75μm in coal) was as high as 46.94%. Conventional flotation was performed on the floating coal sludge of B coal preparation plant, and the process was as follows:

[0083] (1) First, use a stirrer to mechanically stir and slurry the floating coal slime. The slurry speed is set to 1000 r / min, the slurry mixing time is 6 min, and the slurry concentration is adjusted to 80 g / L to obtain the slurry after the first slurry mixing.

[0084] (2) The slurry after the first slurry adjustment is then passed into the first flotation machine for the first flotation. The first flotation reagent is a conventional flotation reagent, in which kerosene is used as the collector, and the kerosene dosage is 5.0 kg / t. 干煤泥 , the foaming agent is octanol, and the dosage of octanol is 0.8 kg / t 干煤泥 , and obtain the first flotation clean coal and the first flotation tailings coal.

[0085] (3) The first flotation clean coal was then mechanically stirred and slurried using a stirrer, and the slurry concentration was adjusted to 40 g / L to obtain the slurry after the second slurry adjustment.

[0086] (4) The slurry after the second slurry adjustment is sent to the secondary flotation machine for the second flotation. During the second flotation, no collector kerosene is added, and only the foaming agent octanol is added. The amount of octanol is 0.1 kg / t. 干煤泥 , and obtain the second flotation clean coal and the second flotation tailings coal.

[0087] (5) The clean coal from the second flotation was sent to the third flotation machine for the third flotation. During the third flotation, no collector kerosene was added, only the foaming agent octanol was added, and the dosage of octanol was 0.03 kg / t. 干煤泥After the third flotation is completed, the third flotation clean coal and the third flotation tailings coal are obtained.

[0088] The third flotation clean coal is used as the clean coal product, the first flotation tail coal and the second flotation tail coal are used as the medium coal product, and the third flotation tail coal is used as the tail coal product. The yield of the clean coal product is 27.36%, and the ash content of the clean coal product is 13.98%.

[0089] Example 2

[0090] The flotation method and reagent system provided by the present invention are used to flotate the coal slime entering the B coal preparation plant, such as Figure 1 As shown, the specific steps are as follows:

[0091] (1) First, a stirrer is used to mechanically stir and slurry the floating coal slime. The slurry concentration is adjusted to 80 g / L. The first collector is added during the slurry mixing process. The first collector is a compound of dodecane and n-pentanoic acid in a mass ratio of 1:1. The dosage of the first collector is 1.5 kg / t 干煤泥 The slurry mixing speed was set to 1200 r / min, the slurry mixing time was 6 min, and the slurry after the first slurry mixing was obtained.

[0092] (2) The slurry after the first pulping is passed into the first flotation machine for the first flotation. The second collector and frother are added during the first flotation. The composition and preparation method of the second collector are as follows. The dosage of the second collector is 1.2 kg / t 干煤泥 MIBC is used as the foaming agent, and the addition amount of MIBC is 0.4 kg / t 干煤泥 , and obtain the first flotation clean coal and the first flotation tailings coal.

[0093] The second collector is a reagent with high capture and specific sorting properties. The specific preparation method is as follows: ① Place 1 part of fatty alcohol polyoxyethylene ether AEO9, 5 parts of oleic acid diethanolamide ODEA, 7 parts of dodecane, 7 parts of n-pentanoic acid, 1 part of nonylphenol polyoxyethylene ether NP10, 2 parts of amyl benzoate, and 0.2 parts of amino acid type sodium coconut glycolate in a container; ② Use an electric stirrer to pre-mix the above samples at a stirring speed of 500 r / min and a stirring time of 10 min to obtain a mixture; ③ Perform ultrasonic treatment on the mixture, insert the ultrasonic head into the container for ultrasonic treatment, the ultrasonic frequency is 22 KHz, and the ultrasonic treatment time is 15 min to obtain the second collector.

[0094] (3) The first flotation clean coal is passed into the second flotation machine for the second flotation. When the scraping time is 75s, the second collector is added. The dosage of the second collector is 0.8 kg / t to obtain the second flotation clean coal and the second flotation tail coal.

[0095] (4) The second flotation clean coal is subjected to a high-speed shearing slurry adjustment. The slurry concentration is adjusted to 40 g / L during the slurry adjustment. A small amount of the first collector is added during the slurry adjustment. The addition amount of the first collector is 0.15 kg / t. 干煤泥 The slurry adjustment speed was set to 2000 r / min, the slurry adjustment time was 7 min, and the slurry after the second slurry adjustment was obtained.

[0096] (5) The slurry after the second slurry adjustment is passed into the third flotation machine for the third flotation, and a small amount of MIBC is added. The MIBC dosage is 0.02 kg / t 干煤泥 , and obtain the third flotation clean coal and the third flotation tailings coal.

[0097] (6) After the third flotation, the ash content of the clean coal from the third flotation is measured. For the coal sludge from B Coal Preparation Plant, due to its extremely poor floatability, the ash content of the clean coal after the third flotation is usually greater than 12%, which is difficult to meet the standard. At this time, it is necessary to measure the ash content of the clean coal in each flotation tank of the third flotation machine. The part with the ash content that meets the standard will be used as the clean coal product, and the part with the ash content that does not meet the standard will be used as the fourth flotation feed. No collector is added during the fourth flotation process, but a small amount of MIBC is added. The amount of MIBC is 0.01 kg / t 干煤泥 , and obtain the fourth flotation clean coal and the fourth flotation tailings coal.

[0098] After the fourth flotation, the ash content of the fourth flotation clean coal was measured. If the ash content met the standard, the fourth flotation clean coal and the third flotation clean coal that met the standard ash content were mixed as the final clean coal product, the second flotation tail coal, the third flotation tail coal and the fourth flotation tail coal were mixed into the medium coal product, and the first flotation tail coal was used as the tail coal product for concentration, sedimentation and filtration. The yield of the clean coal product was 56.37%, and the ash content of the clean coal product was 11.38%.

[0099] Table 1. Comparison of test results of Examples 1-2 and Comparative Examples 1-2

[0100]

[0101] By comparing the test results obtained in Example 1 and Comparative Example 1 and in Example 2 and Comparative Example 2, it can be found that:

[0102] After flotation using the flotation methods and flotation reagents of Examples 1 and 2 of the present invention, the yield of the clean coal product is greatly improved while meeting the ash content requirements of the clean coal product, indicating that the flotation method and flotation reagent of the present invention can well enhance the flotation effect of high-ash fine-grained difficult-to-float coal slime.

[0103] In the present invention, the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0104] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A flotation agent suitable for high-ash fine-grained difficult-to-float coal slime, characterized in that: The invention comprises a first collector, a second collector and a foaming agent; wherein the first collector is composed of dodecane and n-valeric acid; the second collector is composed of fatty alcohol polyoxyethylene ether, oleic acid diethanolamide, dodecane, n-valeric acid, nonylphenol polyoxyethylene ether, amyl benzoate and amino acid type sodium coconut glycolate; and the foaming agent is methyl isobutyl carbinol.

2. The flotation reagent according to claim 1, characterized in that: In the first collector, the mass ratio of dodecane to n-pentanoic acid is (0.5-3.0): (0.5-3.0).

3. The flotation reagent according to claim 1, characterized in that: In the second collector, the mass ratio of the fatty alcohol polyoxyethylene ether, the oleic acid diethanolamide, the dodecane, the n-pentanoic acid, the nonylphenol polyoxyethylene ether, the amyl benzoate and the amino acid type sodium coconut glycolate is (0.6~1.0):(3.0~5.0):(5.0~8.0):(5~8.0):(0.6~1.0):(0.5~1.5):(0.1~0.3).

4. A flotation method suitable for high-ash fine-grained difficult-to-float coal slime, characterized in that: Using the flotation reagent according to any one of claims 1 to 3, the flotation method comprises the following steps: S1, mechanically stirring and slurrying the coal slime, adding the first collector during the mechanical stirring and slurrying process to obtain a first slurrying slurry; S2, passing the slurry after the first slurry adjustment into a first flotation machine for first flotation, and sequentially adding the second collector and the frother during the first flotation process to obtain first flotation clean coal and first flotation tail coal; S3, passing the first flotation clean coal into a secondary flotation machine for second flotation, adding the second collector during the second flotation process to obtain second flotation clean coal and second flotation tail coal; S4, subjecting the secondary flotation clean coal to high-speed shearing slurry adjustment, and adding the first collector during the high-speed shearing slurry adjustment process to obtain a second slurry adjustment slurry; S5, passing the slurry after the second slurry adjustment into a third-selection flotation machine for third flotation, adding the frother during the third flotation process to obtain third flotation clean coal and third flotation tail coal; S6, measuring the ash content of the third flotation clean coal, if the ash content of the third flotation clean coal meets the standard, the third flotation clean coal is directly used as the clean coal product, the second flotation tail coal and the third flotation tail coal are used as the medium coal product, and the first flotation tail coal is used as the tail coal product, and is subjected to concentration, sedimentation and filtration treatment; If the ash content of the third flotation clean coal does not meet the standard, the third flotation clean coal is passed into the fourth flotation machine for the fourth flotation, and the frother is added during the fourth flotation process to obtain the fourth flotation clean coal and the fourth flotation tail coal. If the ash content of the fourth flotation clean coal meets the standard, the fourth flotation clean coal is blended into the clean coal product, the second flotation tail coal, the third flotation tail coal and the fourth flotation tail coal are blended into the medium coal product, and the first flotation tail coal is used as the tail coal product for concentration, sedimentation and filtration treatment.

5. The flotation method according to claim 4, characterized in that: In step S1, the concentration of the ore pulp after the first slurry adjustment is 80-100 g / L; and / or, the rotation speed of the mechanical stirring slurry adjustment is 1200-1500 r / min; and / or, the time of the mechanical stirring slurry adjustment is 2-6 min; and / or, the amount of the first collector added during the mechanical stirring slurry adjustment is 0.5-1.5 kg / t 干煤泥 .

6. The flotation method according to claim 4, characterized in that: In step S2, the amount of the second collector added during the first flotation process is 0.5-3 kg / t 干煤泥 ; and / or, the amount of the frother added during the first flotation process is 0.2~1 kg / t 干煤泥 .

7. The flotation method according to claim 4, characterized in that: In step S3, the amount of the second collector added during the second flotation process is 0.5-2.0 kg / t 干煤泥 .

8. The flotation method according to claim 4, characterized in that: In step S4, the concentration of the slurry after the second slurry adjustment is 40-60 g / L; and / or the rotation speed of the high-speed shear slurry adjustment is 1900-2100 r / min; and / or the time of the high-speed shear slurry adjustment is 4-8 min; and / or the amount of the first collector added during the high-speed shear slurry adjustment is 1 / 10-1 / 7 of the amount of the second collector added during the first flotation process.

9. The flotation method according to claim 4, characterized in that: In step S5, the amount of the frother added in the third flotation process is 0.01-0.04 kg / t 干煤泥 .

10. The flotation method according to claim 4, characterized in that: In steps S1 to S5, the first collector is added in a staged addition manner; and / or, the second collector is added in a staged addition manner; and / or, the foaming agent is added in a staged addition manner.

Images