Quality-improving separation method for enhanced washing middling coal ore grinding dissociation-re-flotation
By adding a composite dissociation promoter to middlings coal for grinding and dissociation treatment, the problem of incomplete dissociation of middlings coal is solved, and the production of low-ash clean coal with high efficiency separation and high recovery rate is achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHONGQING CHANGNENG ENVIRONMENTAL TECH GRP CO LTD
- Filing Date
- 2026-03-25
- Publication Date
- 2026-05-05
AI Technical Summary
In existing technologies, the dissociation depth of middlings coal is insufficient, resulting in a large amount of coal gangue intergrowth remaining in the dissociated material, which affects the flotation process and causes the ash content and yield of clean coal to fall short of standards.
A composite dissociation promoter is used to perform grinding and dissociation treatment on washed coal, including the combined use of anionic surfactants, dispersants and modifiers. Through chemical action, the tightly coexisting structure of coal and gangue minerals is destroyed, achieving efficient separation.
It significantly reduces the ash content of clean coal, increases the clean coal recovery rate, improves the flotation effect, and obtains a low-ash clean coal product with high recovery rate.
Smart Images
Figure CN121972279A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of coal flotation technology, specifically relating to an enhanced method for improving the separation of washed coal through grinding, liberation, and reflotation. Background Technology
[0002] In recent years, almost all middlings (including some coal slime) from coking coal preparation plants in China have been sold directly or used as fuel for power plants. This is especially true in some small and medium-sized coal preparation plants in coal-rich areas, where, due to immature production technologies, the sale of middlings and coal slime has been sluggish, resulting in large quantities being discarded. This increases environmental pressure on mining areas and represents a significant waste of scarce coal resources. Meanwhile, air pollution caused by the combustion of high-ash coal has led to numerous environmental and social problems, drawing serious attention from the government. Therefore, further processing of middlings to obtain low-ash clean coal and seeking efficient and rational separation processes are of profound significance for the rational utilization of my country's coal resources and environmental protection.
[0003] Middlings re-concentration is an important way to improve clean coal yield. Therefore, developing and researching efficient separation methods to promote the full recovery and value-added utilization of middlings is of great practical significance. Conventional flotation methods, due to insufficient liberation depth of middlings, still contain a large amount of coal gangue intergrowth in the liberated material, negatively impacting the flotation process and causing the clean coal ash content and yield to fall short of expectations. Summary of the Invention
[0004] This invention aims to at least partially solve one of the technical problems in related technologies. Therefore, the main objective of this invention is to provide an enhanced method for improving the quality of middlings coal through grinding, liberation, and reflotation, which aims to fully liberate the middlings coal, reduce the ash content of the clean coal, and improve the clean coal recovery rate.
[0005] The objective of this invention is achieved through the following technical solution: A method for enhancing the quality separation of middlings coal by grinding, dissociation, and reflotation involves adding a prescribed amount of water to the middlings coal to obtain a slurry, followed by adding a composite dissociation promoter for grinding and dissociation treatment.
[0006] The ash minerals in middlings coal are mainly clay minerals, with SiO2, Al2O3 and H2O as the main chemical components. Clay minerals are generally extremely fine particles, mostly small scaly particles less than 0.01 mm embedded in the coal, making them difficult to dissociate and separate. This invention uses a composite dissociation promoter to enable the middlings coal to be fully dissociated, breaking down the closely associated useful minerals and gangue minerals in the ore and separating them into individual mineral particles (mineral monomers). This is beneficial for improving the subsequent separation effect and obtaining low-ash clean coal with high recovery rate.
[0007] In some specific embodiments, the pulping time is 2-60 min, more preferably 5-15 min.
[0008] In some specific embodiments, the composite dissociation promoter includes anionic surfactants, dispersants, and modifiers.
[0009] The composite dissociation promoter in this invention performs grinding and dissociation treatment on washed coal, which is beneficial for the efficient and selective separation of ash and coal, improves the yield of clean coal, and reduces the ash content.
[0010] In some specific embodiments, the anionic surfactant is at least one of sodium dodecyl sulfonate, sodium dodecylbenzene sulfonate, and sodium dodecyl sulfate; the dispersant is at least one of sodium carbonate, sodium hexametaphosphate, and sodium pyrophosphate; and the modifier is at least one of sodium hydroxide and potassium hydroxide.
[0011] In some specific embodiments, the mass ratio of the anionic surfactant, dispersant, and modifier is (1-100):(1-100):600.
[0012] Furthermore, the mass ratio of the anionic surfactant, dispersant, and modifier is (10-50):(10-50):600.
[0013] In some specific embodiments, the solid content of the washed coal in the slurry is 80-400 g / L; the dosage of the composite dissociation accelerator is 600 g / t to 700 g / t (meaning that the dosage of the composite dissociation accelerator per ton of washed coal dry material is 1 to 2 kg).
[0014] Furthermore, the solid content of the washed coal in the slurry is 200-350 g / L; the dosage of the composite dissociation promoter is 200 g / t to 1000 g / t.
[0015] In some specific embodiments, the grinding and dissociation time is 10-30 min, more preferably 15-20 min.
[0016] In some specific embodiments, flotation separation is also performed on the washed coal after grinding and liberation treatment.
[0017] In this invention, a composite dissociation promoter is used to improve the grinding dissociation effect, thereby improving the subsequent flotation effect.
[0018] This flotation separation method can achieve highly selective separation of ash and coal in washed coal based on existing flotation techniques, which is beneficial for reducing the ash content in clean coal and improving the recovery rate of clean coal.
[0019] In some specific embodiments, the collector is at least one of white oil, shale oil and wash oil, the foaming agent is 2-octanol, and the inhibitor is water glass.
[0020] The collector can be a coal flotation collector known in the industry. For example, the collector in this invention is at least one of white oil, shale oil, and composite collectors. The dosage of the collector can be adjusted as needed, for example, it is 3000-6000 g / t, preferably 4000-5000 g / t (meaning the dosage of collector per ton of washed middlings dry coal is 4000-5000 g).
[0021] The frother can be a foaming component known in the industry for use in coal flotation, such as 2-octanol. The dosage of the frother can be adjusted as needed; for example, the dosage is 600-2000 g / t, preferably 1000-1500 g / t (meaning the dosage of frother per ton of washed middlings dry coal is 1000-1500 g).
[0022] The inhibitor is water glass; the dosage of the inhibitor can be adjusted as needed, for example, the dosage of the inhibitor is less than or equal to 2000g / t, preferably 100-1000g / t (meaning the dosage of the inhibitor per ton of washed middlings dry material is 100-1000g).
[0023] In some specific embodiments, the flotation process specifically involves one coarse flotation, one to two sweep flotations, and one to three fine flotations.
[0024] Compared with the prior art, the present invention has at least the following advantages: 1) This invention significantly reduces the surface tension of the slurry entering the mill by adding a composite dissociation promoter during grinding dissociation, making it easier for the slurry to penetrate into the micro-cracks and bonding interface between coal and gangue, effectively reducing the interfacial energy and promoting the crushing action to occur preferentially along the coal-gangue interface. At the same time, the dispersant in the composite dissociation promoter can further enhance the detachment of gangue from the surface of coal particles by means of the stripping effect of the dispersant. In addition, the modifier in the composite dissociation promoter can achieve efficient dissociation of washed coal through chemical actions such as dissolution and corrosion, under the synergy of grinding mechanical force, destroying the tight symbiotic structure between coal and gangue minerals, and separating it into coal monomers and mineral monomers.
[0025] 2) The grinding and dissociation method provided by the present invention uses the composite dissociation promoter to grind and dissociate the washed coal, which can effectively improve the high efficiency and high selectivity of ash and coal separation, which is beneficial to improving the efficiency of clean coal and reducing its ash content; at the same time, it significantly improves the separation selectivity of coal and ash minerals in the subsequent flotation process, thereby stably obtaining low ash clean coal products while ensuring high recovery rate.
[0026] 3) The flotation treatment method provided by the present invention benefits from the grinding and dissociation treatment process of the composite dissociation promoter. Based on existing flotation methods, it can achieve high selective separation of ash and coal in washed coal, which is beneficial to reduce the ash content in clean coal and improve the recovery rate of clean coal. Attached Figure Description
[0027] To more clearly illustrate the specific embodiments of the present invention, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below.
[0028] Figure 1 A process flow diagram of an enhanced washing coal grinding, dissociation-reflotation upgrading and separation method provided for embodiments of the present invention; Detailed Implementation
[0029] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. The following embodiments are merely descriptive and not limiting, and should not be construed as limiting the scope of protection of the present invention.
[0030] When a quantity, concentration, or other value or parameter is described as a range, preferred range, or preferred upper and lower limits, it should be understood that it is equivalent to specifically disclosing any range by combining any pair of upper or preferred values with any lower or preferred values, regardless of whether the range is specifically disclosed. Unless otherwise stated, the numerical range values listed herein include the endpoints of the range and all integers and fractions within that range.
[0031] Unless otherwise stated, all percentages, parts, ratios, etc. in this document are by weight.
[0032] The materials, methods, and embodiments described herein are exemplary and should not be construed as limiting unless otherwise stated.
[0033] In the following embodiments, the washed coal is a product obtained by the pilot coal washing plant during the coal washing process. Specifically, the washed coal used comes from a coal washing plant in Inner Mongolia, and its air-dry basis ash content is 44.73%. Example 1
[0034] This embodiment provides a method for enhancing the separation and re-flotation of washed coal through grinding, which includes the following steps: Step 1): Pulping Weigh 150g of washed coal and slurry it with 1L of water for 10 minutes to obtain a mineral slurry. Step 2): Grinding and Liberation The slurry obtained in step 1) is poured into a ball mill, and 650 g / t of composite dissociation promoter is added and milled for 15 min to achieve full dissociation and obtain middlings slurry; the composite dissociation promoter is a complex of sodium dodecyl sulfonate, sodium carbonate and sodium hydroxide in a mass ratio of 20:30:600.
[0035] Step 3): Flotation according to Figure 1 The flotation process is carried out, and the specific steps are as follows: Pour the coal slurry obtained in step 2) into a 1.5L flotation cell, add inhibitors, collectors and frothers, then turn on the aeration switch and perform roughing, scavenging and cleaning operations to obtain clean coal products and tailings.
[0036] The collector is washing oil, with a dosage of 5000 g / t; the frother is 2-octanol, with a dosage of 1500 g / t; the depressant is water glass, with a dosage of 500 g / t; during the flotation process, the pulp concentration is 200 g / L, the roughing is performed once, and the scavenging and cleaning are performed twice each. Experimental results under the above experimental conditions: Example 2
[0037] Compared with Example 1, the only difference is the type of dissociation promoter: Group (I): Sodium dodecyl sulfonate; Group (II): Sodium carbonate; Group (III): Sodium hydroxide; Group (IV): Blank; Example 3
[0038] Compared with Example 1, the only difference is the type of anionic surfactant: Group (I): Sodium dodecylbenzenesulfonate; Group (II): Sodium dodecyl sulfate.
[0039] The test results are as follows: Example 4
[0040] Compared with Example 1, the only difference is the type of dispersant in the composite dissociation accelerator: Group (I): Sodium hexametaphosphate; Group (II): Sodium pyrophosphate.
[0041] The test results are as follows: Example 5
[0042] Compared to Example 1, the only difference is the type of modifier: potassium hydroxide.
[0043] The test results are as follows: Example 6
[0044] Compared with Example 1, the only difference is that the dosage of anionic surfactant, dispersant and modifier in the composite dissociation promoter and composite modifier are as follows: Group (I): 10g / t, 10g / t, 600g / t; Group (II): 60g / t, 60g / t, 600g / t.
[0045] The test results are as follows: Example 7
[0046] Compared with Example 1, the only difference is the amount of composite dissociation promoter used: Group (I): 200g / t; Group (II): 1000g / t.
[0047] The test results are as follows: Example 8 Compared with Example 1, the only difference is that the types of collectors are: Group (I): white oil; Group (II): shale oil.
[0048] The test results are as follows: Example 9
[0049] Compared with Example 1, the only difference is the grinding and dissociation time: Group (I): 10 min; Group (II): 30 min; The test results are as follows: Example 10
[0050] Compared with Example 1, the only difference is the amount of washing oil used: Group (I): 300g / t; Group (II): 6000g / t; The test results are as follows: Example 11
[0051] Compared with Example 1, the only difference is the amount of inhibitor used: Group (I): 0 g / t; Group (II): 3000 g / t.
[0052] The test results are as follows: Example 12
[0053] Compared with Example 1, the only difference is the amount of foaming agent used: Group (I): 3000g / t; Group (II): 500g / t.
[0054] The test results are as follows: Example 13
[0055] Compared with Example 1, the only difference is that the middlings coal is directly floated without grinding and liberation. The experimental results are as follows: Example 14
[0056] Compared with Example 1, the only difference is that no composite dissociation promoter is added during the dissociation of washed coal during grinding; The test results are as follows: In summary, comparing Examples 1 and 2 shows that the synergistic effect of each component in the composite dissociation promoter is better than that of a single component. The composite system of sodium dodecyl sulfonate, sodium carbonate, and sodium hydroxide performs best in reducing ash content and improving clean coal recovery. Comparing Examples 1 and Examples 3-13 shows that grinding dissociation of middlings can improve the degree of dissociation of middlings, creating prerequisites for flotation and facilitating the production of low-ash, high-quality clean coal. Comparing Examples 1 and 14 shows that the composite dissociation promoter can significantly improve grinding dissociation, improve the ash selectivity of subsequent flotation, and improve the quality of the concentrate. In other words, compared to traditional grinding with physical crushing, this invention, by adding specific reagents in a ball mill, weakens the interfacial bonding force between coal and impurities (mainly gangue) through chemical action, achieving a synergistic effect of "physical crushing" and "chemical stripping," thereby obtaining a product with a higher degree of dissociation and creating superior conditions for subsequent flotation.
[0057] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention.
Claims
1. A method for enhancing the separation and re-flotation of washed coal through grinding, characterized in that, A slurry is obtained by adding the prescribed amount of water to the washed coal, and then a composite dissociation promoter is added for grinding and dissociation treatment.
2. The enhanced washing coal grinding, liberation-reflotation method for upgrading and separating coal according to claim 1, characterized in that, The composite dissociation promoter includes anionic surfactants, dispersants, and modifiers.
3. The enhanced washing coal grinding, liberation-reflotation method for upgrading and separating coal according to claim 2, characterized in that, The anionic surfactant is at least one of sodium dodecyl sulfonate, sodium dodecylbenzene sulfonate, and sodium dodecyl sulfate; the dispersant is at least one of sodium carbonate, sodium hexametaphosphate, and sodium pyrophosphate; and the modifier is at least one of sodium hydroxide and potassium hydroxide.
4. The enhanced washing coal grinding, liberation-reflotation method for upgrading and separating coal according to claim 3, characterized in that, The mass ratio of the anionic surfactant, dispersant, and modifier is (1-100):(1-100):
600.
5. The enhanced washing coal grinding, liberation-reflotation method for upgrading and separating coal according to claim 4, characterized in that, The solid content of washed coal in the slurry is 80-400 g / L; the dosage of the composite dissociation promoter is 200 g / t to 1000 g / t.
6. The enhanced washing coal grinding, liberation-reflotation method for upgrading and separating coal according to claim 1, characterized in that, It also includes flotation separation of washed coal after grinding and dissociation.
7. The enhanced washing coal grinding, liberation-reflotation method for upgrading and separating coal according to claim 6, characterized in that, The amount of collector used in the flotation separation process is 3000-6000 g / t, preferably 4000-5000 g / t; the amount of frother used is 600-2000 g / t, preferably 1000-1500 g / t; and the amount of inhibitor used is ≤2000 g / t, preferably 100-1000 g / t.
8. The enhanced washing coal grinding, liberation-reflotation method for upgrading and separating coal according to claim 7, characterized in that, The collector is at least one of white oil, shale oil and wash oil, the foaming agent is 2-octanol, and the inhibitor is water glass.
9. The enhanced washing coal grinding, liberation-reflotation method for upgrading and separating coal according to claim 8, characterized in that, The flotation process specifically involves one roughing flotation, one to two sweeping flotations, and one to three fine flotations.