Interface regulation and control method capable of improving ultrafine crushing and flotation deliming efficiency of anthracite

Abstract

The invention discloses an interface regulation and control method capable of improving ultrafine crushing and flotation deliming efficiency of anthracite, and belongs to the technical field of coal dressing. The method comprises the steps of first-stage fine grinding, size mixing, pre-selection and second-stage fine grinding, and the obtained second-stage fine grinding product is subjected to size mixing and roughing to obtain roughing concentrate; carrying out primary concentration on the roughed concentrate; an interface regulating agent is introduced in the initial stage of ultrafine grinding of the anthracite to regulate the surface properties of coal particles, on the other hand, early-stage size mixing and pre-selection are carried out before second-stage fine grinding, the use amount of a collecting agent and a foaming agent is increased, meanwhile, the number of flotation and concentration stages is reduced, the effect of efficiently removing ash of the anthracite is achieved, and the method is suitable for industrial production. And an anthracite ultrafine crushing-flotation deep ash reduction process can be realized.

Description

Technical Field

[0001] The present invention belongs to the technical field of coal preparation, and specifically relates to an interface regulation method that can improve the ultra-fine grinding and flotation deashing efficiency of anthracite. Background Art

[0002] Anthracite is a high-value scarce coal type, which has the advantages of high graphitization degree and low impurity content. After deep ash reduction, it can be used to prepare various coal-based carbon materials such as activated carbon, graphene, carbon electrodes, graphene, etc. Whether it is a physical ash reduction method or a chemical ash reduction method, it is necessary to dissociate the inorganic components in anthracite through ultra-fine grinding. However, during the ultra-fine grinding process, due to the sharp decrease in the particle size of coal particles, the surface energy of the particles increases, the interaction force between coal particles enhances, forming a thermodynamically unstable system, which is prone to hydrophobic agglomeration, resulting in an increase in the viscosity of the coal slurry and a sharp decline in the fine grinding efficiency.

[0003] Ultra-fine grinding is an essential means for the deep dissociation of anthracite. The longer the grinding time, the better the dissociation effect of the coal sample. However, too long grinding time will exacerbate the oxidation degree of the sample and increase the coverage of gangue minerals on the surface, deteriorating the flotation effect. In addition, in the flotation system, the aggregates formed by ultra-fine particles are prone to entrain high-ash fine gangue minerals, contaminating the flotation clean coal products, and also resulting in the need to increase multi-stage cleaning operations to achieve the purpose of deep ash reduction.

[0004] Based on the above technical difficulties in the traditional process, the problems of low ultra-fine grinding efficiency of anthracite and complex flotation deashing process have not been well solved, and it is impossible to effectively improve the high-efficiency ultra-fine grinding and flotation deashing effects of anthracite slime. Summary of the Invention

[0005] The present invention overcomes the deficiencies of the prior art and proposes an interface regulation method that can improve the ultra-fine grinding and flotation deashing efficiency of anthracite, and solves the problem of being unable to effectively improve the high-efficiency ultra-fine grinding and flotation deashing effects of anthracite slime.

[0006] The present invention is realized through the following technical solutions: An interface regulation method that can improve the ultra-fine grinding and flotation deashing efficiency of anthracite, comprising the following steps: Step 1, primary fine grinding: adding an interface regulator of 0.2 - 0.3 Kg / t of coal slime to conduct primary fine grinding on anthracite coal slime; Step 2, pulp adjustment and pre-selection: screening the product of primary fine grinding, diluting the undersize product, adding a collector and a frother to adjust the pulp, and then feeding it into a pre-selection flotation machine for separation. The dosage of the collector is 2 - 3 Kg / t of coal slime, and the dosage of the frother is 0.2 - 0.3 Kg / t of coal slime to obtain a pre-selection concentrate; Step 3, secondary fine grinding: adding the above-mentioned interface regulator of 0.2 - 0.3 Kg / t of coal slime to the pre-selection concentrate for secondary fine grinding; Step 4: Adjust the pulp density of the obtained second-stage finely ground product and conduct rough selection to obtain rough concentrate. Step 5: Conduct primary cleaning on the rough concentrate.

[0007] Preferably, the interfacial regulator is one or any combination of lignosulfonate, polycarboxylate, and naphthalene sulfonate formaldehyde condensate.

[0008] Preferably, the collector is kerosene or diesel oil, and the frother is sec-octanol or methyl isobutyl carbinol.

[0009] Preferably, in Step 2, the product of the first-stage fine grinding passes through a 200-mesh high-frequency screen. The oversize product is returned to the ball mill for continuous grinding operation, and the undersize product is diluted with water and then adjusted with a collector and a frother.

[0010] Preferably, for the first-stage fine grinding, the grinding conditions are a grinding concentration of 60 - 70%, a ball-to-material ratio of 3:1, a filling rate of 45 - 55%, and a grinding time of 0.25 - 0.35 h.

[0011] Preferably, for the second-stage fine grinding, the grinding conditions are a grinding concentration of 25 - 35%, a ball-to-material ratio of 4:1, and a grinding time of 0.5 - 1.5 h.

[0012] Preferably, in Step 4, the second-stage finely ground product is diluted with water and fed into a pulp preprocessor, and a collector and a frother are added for pulp adjustment.

[0013] Preferably, the collector is kerosene, with a dosage of 1 - 2 Kg / t of slime, and the frother is sec-octanol, with a dosage of 0.25 - 0.35 Kg / t of slime.

[0014] More preferably, in Step 4, the pulp after pulp adjustment is diluted with water and fed into a roughing flotation machine to obtain rough concentrate and rough tailings.

[0015] More preferably, in Step 5, the rough concentrate is diluted with water and fed into a primary cleaning flotation machine for separation to obtain primary cleaning concentrate and primary cleaning tailings. The primary cleaning concentrate is dehydrated by a clean coal filter press to obtain clean coal products.

[0016] The beneficial effects of the present invention compared with the prior art are as follows: By adding an interfacial regulator, the present invention can achieve efficient ultrafine grinding and flotation deashing of anthracite slime on the basis of simplifying the ultrafine pulverization - flotation process of anthracite.

[0017] The above interface regulator is an ionic surfactant, which can adsorb on the surface of coal particles to change their surface physicochemical properties, such as the ratio of hydrophobic and hydrophilic functional groups on the surface of coal particles, surface potential, hydrophilicity and hydrophobicity, etc., reduce the spontaneous agglomeration between particles during grinding, and reduce the viscosity of the pulp. In addition, the macromolecules in some regulators can also adsorb inside the new cracks to compensate for the internal unsaturated bond energy, effectively prevent the closure of cracks on the surface of coal particles, and improve the grindability of coal particles. The flotation separation of minerals is mainly affected by the surface physicochemical properties of minerals and the properties of the pulp, and to a large extent by the grinding operation. After the interface properties are regulated, the repulsive force between coal particles and gangue minerals increases, promoting the dispersibility and stability between particles, reducing the mechanical entrainment of high-ash components and the covering of inorganic minerals on the surface of coal particles, thereby greatly increasing the flotation deashing efficiency and simplifying the production process. Specifically: 1. The present invention creatively proposes a method for improving the ultra-fine grinding efficiency and flotation deashing efficiency of anthracite slime by using an interface regulator. An interface regulator is added during the ultra-fine grinding process of anthracite slime to adjust the surface potential, the ratio of hydrophobic and hydrophilic functional groups of coal particles, change the wettability of the surface of coal particles, improve the dispersibility of coal particles, reduce the spontaneous agglomeration between coal particles, reduce the viscosity of the pulp, and improve the ultra-fine grinding efficiency of anthracite.

[0018] 2. On the other hand, in the subsequent flotation process, due to the change in the physicochemical properties of the surface of coal particles, the agglomeration between particles can be reduced, the repulsive force between coal particles and gangue particles can be increased, the pollution of gangue minerals to flotation concentrates can be reduced, and the number of cleaning sections required for deep flotation deashing can be reduced, thereby improving the efficiency of flotation deashing. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is the process flow diagram of the method described in Example 1; Figure 2 is the process flow diagram of the method described in Example 4; Figure 3 is the process flow diagram of the method described in Example 7. DETAILED DESCRIPTION OF THE INVENTION

[0020] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention clearer, the present invention will be further described in detail in combination with examples and drawings. It should be understood that the specific examples described herein are only used to explain the present invention and are not used to limit the present invention. The technical solutions of the present invention will be described in detail below in combination with examples and drawings, but the protection scope is not limited by this.

[0021] Example 1: This embodiment proposes an interfacial regulation method that can improve the ultra-fine pulverization and flotation deashing efficiency of anthracite; the flotation concentrate product of anthracite with a particle size of -0.5mm from a certain place in southern Shanxi is selected as the raw material, with an ash content of 8.72%, and is processed as follows Figure 1 in the following treatment method.

[0022] Step 1, primary fine grinding: Use a ball mill to perform primary fine grinding on the above raw materials. The grinding conditions are a grinding concentration of 65%, a ball-to-material ratio of 3:1, a filling rate of 50%, and 0.25 kg / t of lignosulfonate is added as an interfacial regulator. After grinding for 0.3 h, a primary fine grinding product with a proportion of -200 mesh of 85.7% is obtained.

[0023] Step 2, secondary fine grinding: The product of primary fine grinding passes through a 200-mesh high-frequency screen. The oversize product is returned to the ball mill for continuous grinding operation, and the undersize product is diluted with water and then subjected to secondary fine grinding using a vertical stirring mill. The grinding conditions are a grinding concentration of 30%, a ball-to-material ratio of 4:1, and 0.25 kg / t of lignosulfonate is added as a regulator. After grinding for 1 h, a secondary fine grinding product with a median particle size D50 = 7.42 μm is obtained.

[0024] Step 3, pulp conditioning: The product of secondary fine grinding is diluted with water to a concentration of 100 g / L and fed into the pulp pre-treater, and collector kerosene and frother sec-octanol are added for pulp conditioning. The dosage of kerosene is 1.5 Kg / t of coal slime, and the dosage of frother is 0.3 Kg / t of coal slime.

[0025] Step 4, rough selection and first-stage cleaning: The conditioned coal slurry is diluted with water to a concentration of 40 g / L and fed into the roughing flotation machine to obtain roughing concentrate and roughing tailings. The ash content of the roughing concentrate is 3.69%, and the yield is 50.16%. The roughing concentrate is diluted with water to a concentration of 30 g / L and fed into the first-stage cleaning flotation machine for separation to obtain first-stage cleaning concentrate and first-stage cleaning tailings. The ash content of the first-stage cleaning concentrate is 2.21%, and the yield is 31.37%.

[0026] Step 5, second-stage cleaning: The first-stage cleaning concentrate is diluted with water to a concentration of 30 g / L and fed into the second-stage cleaning flotation machine for separation to obtain second-stage cleaning concentrate and second-stage cleaning tailings. The ash content of the second-stage cleaning concentrate is 1.96%, and the yield is 20.18%. The second-stage cleaning concentrate is dehydrated by a clean coal filter press to obtain a clean coal product, and the roughing tailings, first-stage cleaning tailings, and second-stage cleaning tailings are dehydrated by a tail coal filter press to obtain a tail coal product. The yield of the above flotation concentrate is the total cumulative yield after conversion. The product indexes of each stage of Example 1 are shown in Table 1.

[0027] Example 2: The difference from Example 1 is that the interfacial regulator is sodium polycarboxylate, with a dosage of 0.5 kg / t of coal slime. The product indexes of each stage of Example 2 are shown in Table 2.

[0028] Example 3: The difference from Example 1 is that the interfacial regulator is naphthalene sulfonate formaldehyde condensate, with a dosage of 0.5 kg / t of slime. The product indexes at each stage of Example 3 are shown in Table 3.

[0029] Control Example 1: The difference from Examples 1 - 3 is that no interfacial regulator is added. The product indexes at each stage of Control Example 1 are shown in Table 4. Due to the absence of the interfacial regulator, the concentrate yield after secondary beneficiation is greater than 20%, and tertiary beneficiation is required.

[0030] Example 4: This example presents an interfacial regulation method that can improve the ultra - fine grinding and flotation de - ash efficiency of anthracite. The raw slime of anthracite with a particle size of - 1 mm from a certain place in southern Shanxi is selected as the raw material, with an ash content of 25.6%, and is processed through the following Figure 2 treatment method.

[0031] Step 1, primary fine grinding: Use a ball mill to conduct primary fine grinding on the above - mentioned raw material. The grinding conditions are a grinding concentration of 65%, a ball - to - material ratio of 3:1, a filling rate of 50%, and add 0.25 kg / t of lignosulfonate sodium as the interfacial regulator. Grind for 0.3 h to obtain a primary fine - grinding product with a - 200 - mesh proportion of 78.3%.

[0032] Step 2, pulp adjustment and pre - separation: The primary fine - grinding product passes through a 200 - mesh high - frequency screen. The over - screen product returns to the ball mill for continuous grinding operation, and the under - screen product is diluted with water to a concentration of 80 g / L, and then collector kerosene and frother sec - octanol are added for pulp adjustment and then fed into a pre - separation flotation machine for separation. The dosage of kerosene is 1 kg / t of slime, and the dosage of sec - octanol is 0.2 kg / t of slime, to obtain pre - separation concentrate and pre - separation tailings. The ash content of the pre - separation concentrate is 8.47%, and the yield is 65.46%.

[0033] Step 3, secondary fine grinding: The pre - separation concentrate is subjected to secondary fine grinding using a vertical agitation mill. The grinding conditions are a grinding concentration of 30%, a ball - to - material ratio of 4:1, and add 0.25 kg / t of lignosulfonate sodium as the regulator. Grind for 0.75 h to obtain a secondary fine - grinding product with a median particle size D50 = 11.13 μm.

[0034] Step 4, pulp preparation and rough selection: The product of the second-stage fine grinding is diluted with water to a concentration of 100 g / L and fed into the pulp preprocessor. The collector kerosene and the frother sec-octanol are added for pulp preparation. The dosage of kerosene is 1.5 kg / t of slime, and the dosage of the frother is 0.3 kg / t of slime. The pulp after pulp preparation is diluted with water to a concentration of 40 g / L and fed into the roughing flotation machine to obtain the roughing concentrate and the roughing tailings. The ash content of the roughing concentrate is 4.65%, and the yield is 49.07%.

[0035] Step 5, first-stage separation, second-stage separation, and third-stage separation: The roughing concentrate is diluted with water to a concentration of 30 g / L and fed into the first-stage cleaning flotation machine for separation to obtain the first-stage cleaning concentrate and the first-stage cleaning tailings. The ash content of the first-stage cleaning concentrate is 4.08%, and the yield is 36.12%. The first-stage cleaning concentrate is diluted with water to a concentration of 30 g / L and fed into the second-stage cleaning flotation machine for separation to obtain the second-stage cleaning concentrate and the second-stage cleaning tailings. The ash content of the second-stage cleaning concentrate is 3.56%, and the yield is 21.78%. The second-stage cleaning concentrate is diluted with water to a concentration of 25 g / L and fed into the third-stage cleaning flotation machine for separation to obtain the third-stage cleaning concentrate and the third-stage cleaning tailings. The ash content of the third-stage cleaning concentrate is 2.48%, and the yield is 12.87%.

[0036] The third-stage cleaning concentrate is dehydrated by a clean coal filter press to obtain the clean coal product. The roughing tailings, the first-stage cleaning tailings, the second-stage cleaning tailings, and the third-stage cleaning tailings are dehydrated by a tailing coal filter press to obtain the tailing coal product. The yield of the above flotation concentrate is the total cumulative yield after conversion. The product indexes of each stage of Example 4 are shown in Table 5. Different from Examples 1-3, a pre-selection link is added before the second-stage fine grinding process.

[0037] Example 5: The difference from Example 4 is that the interfacial regulator is sodium polycarboxylate, and the dosage is 0.5 kg / t of slime. The product indexes of each stage of Example 5 are shown in Table 6.

[0038] Example 6: The difference from Example 4 is that the interfacial regulator is naphthalene sulfonate formaldehyde condensate, and the dosage is 0.5 kg / t of slime. The product indexes of each stage of Example 6 are shown in Table 7.

[0039] Control Example 2: The difference from Examples 4-6 is that no interfacial regulator is added. The product indexes of each stage of Control Example 2 are shown in Table 8.

[0040] Example 7: This embodiment proposes an interfacial regulation method that can improve the ultra-fine pulverization and flotation de-ashing efficiency of anthracite; select the -1mm anthracite slime from a certain mine in Xiafalü, Yunnan as the raw material, with an ash content of 20.86%, and after the process as shown in Figure 3 is processed.

[0041] Step 1, primary fine grinding: Use a ball mill to conduct primary fine grinding on the above raw materials. The grinding conditions are a grinding concentration of 65%, a ball-to-material ratio of 3:1, a filling rate of 50%, add 0.25 kg / t of lignosulfonate as an interfacial regulator, grind for 0.3 h, and obtain a primary fine grinding product with a -200 mesh proportion of 91.4%.

[0042] Step 2, pulp adjustment and pre-selection: The primary fine grinding product passes through a 200 mesh high-frequency sieve. The oversize product is returned to the ball mill for continuous grinding operation. The undersize product is diluted with water to a concentration of 80 g / L, and after adding the collector kerosene and the foaming agent sec-octanol for pulp adjustment, it is fed into a pre-selection flotation machine for separation. The dosage of kerosene is 2.5 kg / t of coal slime, and the dosage of sec-octanol is 0.25 kg / t of coal slime, obtaining a pre-selection concentrate and a pre-selection tailing. The ash content of the pre-selection concentrate is 3.72%, and the yield is 62.69%.

[0043] Step 3, secondary fine grinding: The pre-selection concentrate is subjected to secondary fine grinding using a vertical agitation mill. The grinding conditions are a grinding concentration of 30%, a ball-to-material ratio of 4:1, add 0.25 kg / t of lignosulfonate as a regulator, grind for 1 h, and obtain a secondary fine grinding product with a median particle size D50 = 5.8 μm.

[0044] Step 4, pulp adjustment and rough selection: The secondary fine grinding product is diluted with water to a concentration of 100 g / L and fed into a pulp pre-processor, and the collector kerosene and the foaming agent sec-octanol are added for pulp adjustment. The dosage of kerosene is 1.5 Kg / t of coal slime, and the dosage of the foaming agent is 0.3 Kg / t of coal slime. The adjusted coal slurry is diluted with water to a concentration of 40 g / L and fed into a rough selection flotation machine, obtaining a rough selection concentrate and a rough selection tailing. The ash content of the rough selection concentrate is 1.84%, and the yield is 38.55%.

[0045] Step 5, first cleaning: The rough selection concentrate is diluted with water to a concentration of 30 g / L and fed into a first cleaning flotation machine for separation, obtaining a first cleaning concentrate and a first cleaning tailing. The ash content of the first cleaning concentrate is 0.99%, and the yield is 21.68%. The first cleaning concentrate is dehydrated by a clean coal filter press to obtain a clean coal product, and the pre-selection tailing, rough selection tailing, and first cleaning tailing are dehydrated by a tail coal filter press to obtain a tail coal product. The yield of the above flotation concentrate is the total cumulative yield after conversion. The product indexes of each stage of Example 7 are shown in Table 9.

[0046] Example 8: The difference from Example 7 is that the interfacial regulator is sodium polycarboxylate, with a dosage of 0.5 kg / t of slime. The product indexes at each stage of Example 8 are shown in Table 10.

[0047] Example 9: The difference from Example 7 is that the interfacial regulator is naphthalene sulfonate formaldehyde condensate, with a dosage of 0.5 kg / t of slime. The product indexes at each stage of Example 9 are shown in Table 11.

[0048] Comparative Example 3: The difference from Examples 7 - 9 is that no interfacial regulator is added. The product indexes at each stage of Comparative Example 3 are shown in Table 12. Since no interfacial regulator is added, the concentrate yields after the first and second roughing are greater than 20%, and a third roughing is required.

[0049] It can be seen from the examples and comparative examples of the present invention that introducing an interfacial regulator at the initial stage of ultrafine grinding of anthracite to regulate the surface properties of coal particles can significantly improve the ultrafine grinding efficiency of anthracite and reduce the grinding time. On the one hand, the process flow is simplified and the grinding energy consumption is reduced. On the other hand, pre-slurrying and pre-selection are carried out before the second-stage fine grinding, the dosages of the collector and the frother are increased, and the number of flotation roughing stages is reduced, so as to efficiently remove the ash content of anthracite, providing a new idea for the ultrafine grinding - flotation deep ash reduction process of anthracite. The above examples are only preferred embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention.

[0050] The above content is a further detailed description of the present invention in combination with specific preferred embodiments. It cannot be determined that the specific embodiments of the present invention are limited thereto. For those of ordinary skill in the art in the technical field to which the present invention belongs, without departing from the premise of the present invention, several simple deductions or substitutions can still be made, which should all be regarded as belonging to the patent protection scope determined by the claims submitted by the present invention.

Claims

1. An interface control method for improving the efficiency of ultrafine grinding and flotation deashing of anthracite, characterized in that: The following steps are involved: Step 1, one-stage fine grinding: adding 0.2-0.3 kg / t of coal slime interface regulator to perform one-stage fine grinding on the anthracite coal slime; Step 2, slurry preparation and pre-selection: the first-stage fine grinding product is screened, the screened product is diluted and the collector and frother are added to prepare the slurry, and then fed into the pre-selection flotation machine for sorting. The collector dosage is 2-3 kg / t coal slime, and the frother dosage is 0.2-0.3 kg / t coal slime to obtain the pre-selected concentrate; Step 3, second-stage fine grinding: adding 0.2-0.3 kg / t coal slime interface regulator to the pre-selected concentrate for second-stage fine grinding; Step 4, slurry adjustment and roughing of the obtained second-stage fine grinding product to obtain a roughing concentrate; Step 5: Perform a primary cleaning on the rougher concentrate.

2. The interface control method for improving the efficiency of ultrafine grinding and flotation deashing of anthracite according to claim 1, characterized in that: The interface regulator is one or any combination of lignin sulfonate, polycarboxylate, and naphthalene sulfonate formaldehyde condensate.

3. The interface control method for improving the efficiency of ultrafine grinding and flotation deashing of anthracite according to claim 1, characterized in that: The collector is kerosene or diesel, and the foaming agent is sec-octanol or methyl isobutyl carbinol.

4. The interface control method for improving the efficiency of ultrafine grinding and flotation deashing of anthracite according to claim 1, characterized in that: In step 2, the first fine grinding product is passed through a 200-mesh high-frequency screen, and the product on the screen is returned to the ball mill for further grinding. The product under the screen is diluted with water and then a collector and a frother are added to prepare the slurry.

5. The interface control method for improving the efficiency of ultrafine grinding and flotation deashing of anthracite according to claim 1, characterized in that: The first stage of fine grinding has the following grinding conditions: grinding concentration 60-70%, ball-to-material ratio 3:1, filling rate 45-55%, and grinding time 0.25-0.35h.

6. The interface control method for improving the efficiency of ultrafine grinding and flotation deashing of anthracite according to claim 1, characterized in that: Second stage fine grinding, grinding conditions are grinding concentration 25-35%, ball to material ratio 4:1, grinding 0.5-1.5h.

7. The interface control method for improving the efficiency of ultrafine grinding and flotation deashing of anthracite according to claim 1, characterized in that: In step 4, the second-stage fine grinding product is diluted with water and fed into a slurry pre-processor, and a collector and a frother are added to adjust the slurry.

8. The interface control method for improving the efficiency of ultrafine grinding and flotation deashing of anthracite according to claim 7, characterized in that: The collector is kerosene, and the amount of kerosene is 1-2 kg / t coal slime. The foaming agent is octanol, and the amount of octanol is 0.25-0.35 kg / t coal slime.

9. The interface control method for improving the efficiency of ultrafine grinding and flotation deashing of anthracite according to claim 8, characterized in that: In step 4, the slurry is diluted with water and fed into a roughing flotation machine to obtain a roughing concentrate and a roughing tailing.

10. The interface control method for improving the efficiency of ultrafine grinding and flotation deashing of anthracite according to claim 8, characterized in that: In step 5, the roughing concentrate is diluted with water and fed into a primary concentrating flotation machine for sorting to obtain a primary concentrating concentrate and a primary concentrating tailings. The primary concentrating concentrate is dehydrated by a clean coal filter press to obtain a clean coal product.

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