Coprocessing flotation method for removing mercury, lead and fluorine in coal
Through the synergistic flotation method of ethanol, hydrogen peroxide and microwave, the problem of poor removal of organic mercury, lead and fluorine in coal was solved, and the removal of harmful elements in coal was achieved in an efficient, low-cost and environmentally friendly manner.
Patent Information
- Application Number
- CN202511074241.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-01
- Publication Date
- 2025-09-19
AI Technical Summary
Existing technologies are difficult to effectively remove harmful elements such as organic mercury, lead, and fluorine from coal, and traditional methods have problems such as high operating costs and environmental unfriendliness.
An ethanol, hydrogen peroxide and microwave synergistic flotation method is adopted. The coal sample mixture is treated with microwaves and then floated, filtered and dried in a flotation tank. Collectors and frothers are used to separate the coal slurry to achieve the synergistic removal of mercury, lead and fluorine in coal.
It improves the removal rate of mercury, lead and fluorine in coal, reduces operating costs, is environmentally friendly, and is suitable for coal resources from different origins.
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Abstract
Description
Technical Field
[0001] The invention relates to the technical field of coal processing, and is a collaborative processing flotation method for removing mercury, lead and fluorine from coal. Background Art
[0002] Coal, a core pillar of global energy consumption, releases pollutants that pose a significant threat to ecological security and human health. Harmful elements such as mercury, lead, and fluorine in coal are largely combined with sulfides like pyrite and iron ore, as well as clay minerals. Upon combustion, these elements transform into pollutants such as gaseous mercury, lead oxides, and hydrogen fluoride, posing environmental risks. Mercury in coal is highly neurotoxic and gradually transforms into highly toxic methylmercury in the environment, accumulating in the food chain. Lead is also highly neurotoxic and developmentally toxic, seriously endangering the growth and health of children. Fluoride can cause endemic diseases such as skeletal fluorosis and dental fluorosis in humans, and is toxic to plants and animals. Effectively addressing these severe environmental and health challenges requires efficient removal of these harmful elements from coal. Given the inability of traditional methods to effectively remove these deeply embedded harmful elements, developing new, environmentally compatible, and cost-effective removal processes is essential.
[0003] Currently, the technologies for removing harmful elements such as mercury, lead, and fluorine from coal mainly include physical, chemical, and biological technologies. Physical separation technologies such as heavy medium separation and flotation mainly utilize the differences in density or surface hydrophilicity between coal and minerals containing mercury, lead, and fluorine to separate them, but are less effective in removing elements distributed in the coal in an organically bound state. Chemical treatment technologies such as leaching and oxidation change the form of mercury, lead, and fluorine through chemical reactions, causing them to dissolve or transform and then be removed. However, they face the problems of high reagent consumption and severe equipment corrosion, resulting in high operating costs. Biological removal technology uses microbial metabolic adsorption and redox to transform elements such as mercury and lead, but its effect on fluorine treatment is limited. It also has the disadvantages of a long reaction cycle and demanding environmental conditions, making it difficult to meet the needs of industrial efficient removal.
[0004] Research has attempted to improve removal efficiency by combining multiple technologies, but existing combined processes still have significant limitations. For example, while microwave-assisted flotation can effectively improve coal pore structure and enhance desulfurization, its research focuses on removing sulfur from coal, while the removal of elements such as mercury, lead, and fluorine has rarely been reported. Hydrogen peroxide and microwave synergistic oxidation processes have been explored in the field of mercury removal, but experiments have shown that while their efficiency for inorganic mercury is high, their removal of organic mercury, lead, and fluorine is limited. Furthermore, they suffer from issues such as high oxidant dosage and poor reaction selectivity.
[0005] Therefore, it has become an inevitable trend to improve the removal efficiency of harmful elements in coal, research and develop a composite treatment process with multi-technology collaboration, and overcome the limitations of existing technologies. At the same time, it is also necessary to strengthen the research on the universality of technology so that the treatment technology can be applied to coal resources from different origins and promote the widespread application of clean and efficient coal utilization technology. Summary of the Invention
[0006] The present invention provides a coordinated flotation method for removing mercury, lead and fluorine from coal, which overcomes the shortcomings of the above-mentioned existing technologies and can effectively solve the problem that the existing technologies for removing harmful elements from coal have poor removal effects on organic mercury, lead and fluorine.
[0007] The technical solution of the present invention is achieved by the following measures: a collaborative flotation method for removing mercury, lead and fluorine from coal, comprising the following steps: Mixing required amounts of coal, alcohol treating agent, oxidant and water to obtain a coal sample mixture; treating the coal sample mixed liquid with microwaves to obtain a treated mixed liquid; The treated mixed liquid is transferred to a flotation tank, and after flotation, filtration and drying, a coal sample with mercury, lead and fluorine removed is obtained.
[0008] The following are further optimizations and / or improvements to the above technical solutions: The alcohol treatment agent is ethanol.
[0009] The above-mentioned oxidant is hydrogen peroxide.
[0010] For every ton of coal, 300L to 1000L of ethanol, 300L to 1200L of hydrogen peroxide and 20m³ to 30m³ of water are added.
[0011] The particle size (diameter) of the above coal samples is 0.1mm to 0.2mm.
[0012] The microwave treatment is carried out under stirring at a temperature of 30°C to 50°C and a microwave power density of 12000W / m 2 Up to 25000W / m 2 , the processing time is 5min to 10min, and the stirring speed is 500rpm to 1000rpm.
[0013] The above flotation is carried out by inflating the flotation tank with air and adding a collector and a frother to carry out flotation.
[0014] The collector is kerosene, and the amount of collector added is 1 kg to 1.5 kg per ton of coal sample mixture.
[0015] The above-mentioned foaming agent is octanol, and the amount of foaming agent added is 100g to 150g per 1 ton of coal sample mixture.
[0016] The present invention provides a collaborative processing flotation method for removing mercury, lead and fluorine from coal, establishes a collaborative processing system consisting of ethanol, hydrogen peroxide, microwaves and flotation, overcomes the limitations of single technology and existing combined technology, and has obvious effects on the removal of mercury, lead and fluorine, and has the advantages of high removal rate, low operating cost, and environmental friendliness, and is suitable for promotion and application. DETAILED DESCRIPTION
[0017] The present invention is not limited to the following embodiments, and specific implementation methods can be determined based on the technical solutions of the present invention and actual conditions. Unless otherwise specified, the various chemical reagents and chemicals mentioned in the present invention are all chemical reagents and chemicals commonly known in the prior art; unless otherwise specified, the percentages in the present invention are all percentages by mass; unless otherwise specified, the solutions in the present invention are all aqueous solutions with water as the solvent, for example, hydrochloric acid solution is an aqueous hydrochloric acid solution; normal temperature and room temperature in the present invention generally refer to temperatures between 15°C and 25°C, and are generally defined as 25°C.
[0018] The present invention will be further described below in conjunction with the embodiments: Example 1: The collaborative flotation method for removing mercury, lead and fluorine from coal comprises the following steps: Mixing required amounts of coal, alcohol treating agent, oxidant and water to obtain a coal sample mixture; treating the coal sample mixed liquid with microwaves to obtain a treated mixed liquid; The treated mixed liquid is transferred to a flotation tank, and after flotation, filtration and drying, a coal sample with mercury, lead and fluorine removed is obtained.
[0019] Example 2: As an optimization of the above example, the alcohol treatment agent is ethanol.
[0020] Example 3: As an optimization of the above example, the oxidant is hydrogen peroxide.
[0021] Example 4: As an optimization of the above example, 300L to 1000L of ethanol, 300L to 1200L of hydrogen peroxide, and 20m³ to 30m³ of water are added per ton of coal. In the present invention, the concentration of the oxidant hydrogen peroxide is 30% by mass.
[0022] Example 5: As an optimization of the above example, the particle size (diameter) of the coal sample is 0.1 mm to 0.2 mm.
[0023] Example 6: As an optimization of the above example, the microwave treatment is microwave treatment under stirring, the treatment temperature is 30°C to 50°C, and the microwave power density is 12000W / m 2 Up to 25000W / m 2, the processing time is 5min to 10min, and the stirring speed is 500rpm to 1000rpm.
[0024] Example 7: As an optimization of the above example, flotation is performed by aerating the flotation tank and adding a collector and a frother to perform flotation.
[0025] Example 8: As an optimization of the above example, the collector is kerosene, and the amount of collector added is 1 kg to 1.5 kg per ton of coal sample mixture.
[0026] Example 9: As an optimization of the above example, the foaming agent is octanol, and the amount of the foaming agent added is 100g to 150g per 1 ton of coal sample mixture.
[0027] Example 10: The coal sample processed in this embodiment is Shan'in coal.
[0028] The Shanyin coal was ground and sieved to a diameter of 0.106 mm. 1 kg of coal sample was taken, and 0.84 L of ethanol, 0.39 L of hydrogen peroxide (concentration 30%) and 25 L of water were added and mixed to obtain a coal sample mixture.
[0029] The coal sample mixture was placed in a microwave reactor for microwave treatment at a microwave temperature of 30 °C and a power density of 14814 W / m 2 , time 5min, stirring 800r / min.
[0030] Place the coal sample mixture after microwave treatment into the flotation tank, start and debug the unit aeration volume to 0.25m 3 / (m 2 ·min); turn on the flotation machine and stir for 2 minutes, then add 1 g of kerosene to the coal sample mixture below the liquid surface; 1 minute later, add 0.12 g of 2-octanol, a foaming agent, to the coal sample mixture below the liquid surface; after stirring, wash the particles deposited at the bottom of the flotation tank into the tail coal container, and filter the coal slurry in the flotation tank to obtain a filter residue. After drying the filter residue, a coal sample with mercury, lead and fluorine removed is obtained.
[0031] The coal sample from which mercury, lead and fluorine elements were removed in this embodiment was tested (test data are shown in Table 1). The mercury removal rate reached 46.04%, the lead removal rate reached 98.50%, and the fluorine removal rate reached 18.30%.
[0032] Example 11: The coal sample processed in this embodiment is Pingyao coal 2.0.
[0033] Pingyao coal 2.0 was ground and sieved to a diameter of about 0.106 mm. 1 kg of coal sample was taken, and 0.84 L of ethanol, 0.77 L of hydrogen peroxide and 25 L of water were added and mixed to obtain a coal sample mixture.
[0034] The coal sample mixture was placed in a microwave reactor for microwave treatment at a microwave temperature of 40 °C and a power density of 18518 W / m 2 , time 5min, stirring 800r / min.
[0035] Place the coal sample mixture after microwave treatment into the flotation tank, start and debug the unit aeration volume to 0.25m 3 / (m 2 ·min); turn on the flotation machine and stir for 2 minutes, then add 1.0 g of kerosene to the surface of the coal sample mixture; 1 minute later, add 0.12 g of 2-octanol, a foaming agent, to the surface of the coal sample mixture; after stirring, wash the particles deposited at the bottom of the flotation tank into a tail coal container, and filter the coal slurry in the flotation tank to obtain a filter residue. After drying the filter residue, a coal sample free of mercury, lead and fluorine is obtained.
[0036] The coal sample from which mercury, lead and fluorine elements were removed in this embodiment was tested (test data are shown in Table 1). The mercury removal rate reached 49.35%, the lead removal rate reached 98.81%, and the fluorine removal rate reached 33.89%.
[0037] Example 12: The coal sample processed in this example is Pingyao coal 3.0.
[0038] Pingyao coal 3.0 was ground and sieved to a diameter of 0.106 mm. 1 kg of coal sample was taken, and 0.42 L of ethanol, 0.39 L of hydrogen peroxide and 25 L of water were added and mixed to obtain a coal sample mixture.
[0039] The coal sample mixture was placed in a microwave reactor for microwave treatment at a microwave temperature of 40 °C and a power density of 22222 W / m 2 , time 10min, stirring 800r / min.
[0040] Place the coal sample mixture after microwave treatment into the flotation tank, start and debug the unit aeration volume to 0.25m 3 / (m 2 ·min); turn on the flotation machine and stir for 2 minutes, then add 1.0 g of kerosene to the surface of the coal sample mixture; 1 minute later, add 0.12 g of 2-octanol, a foaming agent, to the surface of the coal sample mixture; after stirring, wash the particles deposited at the bottom of the flotation tank into a tail coal container, and filter the coal slurry in the flotation tank to obtain a filter residue. After drying the filter residue, a coal sample free of mercury, lead and fluorine is obtained.
[0041] The coal sample from which mercury, lead and fluorine elements were removed in this embodiment was tested (test data are shown in Table 1). The mercury removal rate reached 79.12%, the lead removal rate reached 98.68%, and the fluorine removal rate reached 42.02%.
[0042] Example 13: The coal sample processed in this embodiment is Alaer Jiutuan mixed coal.
[0043] The Alar Jiutuan miscellaneous coal was ground and sieved to a diameter of 0.106 mm. 1 kg of coal sample was taken, and 0.84 L of ethanol, 0.39 L of hydrogen peroxide and 25 L of water were added and mixed to obtain a coal sample mixture.
[0044] The coal sample mixture was placed in a microwave reactor for microwave treatment at a microwave temperature of 30 °C and a power density of 14814 W / m 2 , time 5min, stirring 800r / min.
[0045] Place the coal sample mixture after microwave treatment into the flotation tank, start and debug the unit aeration volume to 0.25m 3 / (m 2 ·min); turn on the flotation machine and stir for 2 minutes, then add 1.0 g of kerosene to the surface of the coal sample mixture; 1 minute later, add 0.12 g of 2-octanol, a foaming agent, to the surface of the coal sample mixture; after stirring, wash the particles deposited at the bottom of the flotation tank into a tail coal container, and filter the coal slurry in the flotation tank to obtain a filter residue. After drying the filter residue, a coal sample free of mercury, lead and fluorine is obtained.
[0046] The coal sample from which mercury, lead and fluorine elements were removed in this embodiment was tested (test data shown in Table 1). The mercury removal rate reached 72.41%, the lead removal rate was 99.36%, the fluorine removal rate was 22.37%, and the clean coal yield was 82.71%.
[0047] Example 14: The coal sample processed in this embodiment is Jundetu raw coal.
[0048] The Jundetu raw coal was ground and sieved to a diameter of 0.106 mm. 1 kg of coal sample was taken, and 0.42 L of ethanol, 1.15 L of hydrogen peroxide and 25 L of water were added and mixed to obtain a coal sample mixture.
[0049] The coal sample mixture was placed in a microwave reactor for microwave treatment at a microwave temperature of 50 °C and a power density of 18518 W / m 2 , time 5min, stirring 800r / min.
[0050] Place the coal sample mixture after microwave treatment into the flotation tank, start and debug the unit aeration volume to 0.25m 3 / (m 2·min); turn on the flotation machine and stir for 2 minutes, then add 1.0 g of kerosene to the surface of the coal sample mixture; 1 minute later, add 0.12 g of 2-octanol, a foaming agent, to the surface of the coal sample mixture; after stirring, wash the particles deposited at the bottom of the flotation tank into a tail coal container, and filter the coal slurry in the flotation tank to obtain a filter residue. After drying the filter residue, a coal sample free of mercury, lead and fluorine is obtained.
[0051] The coal sample from which mercury, lead and fluorine elements were removed in this embodiment was tested (test data are shown in Table 1). The mercury removal rate reached 51.26%, the lead removal rate reached 98.72%, and the fluorine removal rate reached 25.56%.
[0052] Example 15: The coal sample processed in this embodiment is Kuche clean coal.
[0053] The Alar Jiutuan miscellaneous coal was ground and sieved to a diameter of 0.106 mm. 1 kg of coal sample was taken, and 0.84 L of ethanol, 0.39 L of hydrogen peroxide and 25 L of water were added and mixed to obtain a coal sample mixture.
[0054] The coal sample mixture was placed in a microwave reactor for microwave treatment at a microwave temperature of 50 °C and a power density of 18518 W / m 2 , time 10min, stirring 800r / min.
[0055] Place the coal sample mixture after microwave treatment into the flotation tank, start and debug the unit aeration volume to 0.25m 3 / (m 2 ·min); turn on the flotation machine and stir for 2 minutes, then add 1.0 g of kerosene to the surface of the coal sample mixture; 1 minute later, add 0.12 g of 2-octanol, a foaming agent, to the surface of the coal sample mixture; after stirring, wash the particles deposited at the bottom of the flotation tank into a tail coal container, and filter the coal slurry in the flotation tank to obtain a filter residue. After drying the filter residue, a coal sample free of mercury, lead and fluorine is obtained.
[0056] The coal sample from which mercury, lead and fluorine elements were removed in this embodiment was tested (test data are shown in Table 1). The mercury removal rate reached 70.90%, the lead removal rate reached 99.24%, and the fluorine removal rate reached 48.95%.
[0057] Example 16: The coal sample processed in this embodiment is Aksu anthracite.
[0058] The Aksu anthracite was ground and sieved to a diameter of 0.106 mm. 1 kg of coal sample was taken, and 0.84 L of ethanol, 1.15 L of hydrogen peroxide and 25 L of water were added and mixed to obtain a coal sample mixture.
[0059] The coal sample mixture was placed in a microwave reactor for microwave treatment at a microwave temperature of 40 °C and a power density of 22222 W / m 2 , time 15min, stirring 800r / min.
[0060] Place the coal sample mixture after microwave treatment into the flotation tank, start and debug the unit aeration volume to 0.25m 3 / (m 2 ·min); turn on the flotation machine and stir for 2 minutes, then add 1.0 g of kerosene to the surface of the coal sample mixture; 1 minute later, add 0.12 g of 2-octanol, a foaming agent, to the surface of the coal sample mixture; after stirring, wash the particles deposited at the bottom of the flotation tank into a tail coal container, and filter the coal slurry in the flotation tank to obtain a filter residue. After drying the filter residue, a coal sample free of mercury, lead and fluorine is obtained.
[0061] The coal sample from which mercury, lead and fluorine elements were removed in this embodiment was tested (test data are shown in Table 1). The mercury removal rate reached 70.47%, the lead removal rate reached 98.72%, and the fluorine removal rate reached 40.83%.
[0062] Comparative Example 1: The difference from Example 13 is that no ethanol and hydrogen peroxide were added. The coal sample treatment results are shown in Table 2.
[0063] Comparative Example 2: The difference from Example 13 is that no hydrogen peroxide is added. The coal sample treatment results are shown in Table 2.
[0064] Comparative Example 3: The difference from Example 13 is that no ethanol is added. The coal sample treatment results are shown in Table 2.
[0065] Comparative Example 4: The difference from Example 13 is that no hydrogen peroxide is added, and ethanol is replaced by the same volume of methanol. The coal sample treatment results are shown in Table 2.
[0066] Comparative Example 5: The difference from Example 13 is that no ethanol is added, hydrogen peroxide is replaced by potassium permanganate, and the added amount of potassium permanganate is 0.39 kg. The coal sample treatment results are shown in Table 2.
[0067] Comparative Example 6: The difference from Example 13 is that ethanol is replaced by the same volume of methanol. The coal sample treatment results are shown in Table 2.
[0068] Comparative Example 7: The difference from Example 13 is that hydrogen peroxide is replaced by potassium permanganate, and the added amount of potassium permanganate is 0.39 kg. The coal sample treatment results are shown in Table 2. From the above examples and comparative examples, it can be seen that the method of removing mercury, lead and fluorine from coal by synergistically enhancing microwave-assisted flotation by ethanol and hydrogen peroxide has a mild and efficient reaction path under the synergistic effect of multiple factors, compared with the separate physical technology, chemical technology and existing combined removal technology, and its effect is more significant.
[0069] In summary, the present invention offers the following advantages: The synergistic treatment system comprising ethanol, hydrogen peroxide, microwaves, and flotation overcomes the limitations of single technologies and existing combined technologies. Experimental studies have demonstrated that this method is highly effective in removing mercury, lead, and fluorine, offering high removal rates, low operating costs, and environmental friendliness. Ethanol reduces the surface tension of the coal slurry, facilitating the removal of inorganic minerals during flotation. Ethanol is also biodegradable, making it environmentally friendly. Hydrogen peroxide, through its strong oxidizing properties, oxidizes sulfides bound to mercury and lead in the coal, dispersing them for easier subsequent processing. Hydrogen peroxide decomposes into water and oxygen, producing no harmful substances. This synergistic effect not only improves the removal efficiency of mercury, lead, and fluorine from coal, but also reduces the amount of individual reagents used, resulting in both environmental and economic benefits.
[0070] The above technical features respectively constitute the embodiments of the present invention, which have strong adaptability and implementation effect. Non-essential technical features can be added or removed according to actual needs to meet the requirements of different situations.
Claims
1. A collaborative flotation method for removing mercury, lead and fluorine from coal, characterized in that The following steps are involved: Mixing required amounts of coal, alcohol treating agent, oxidant and water to obtain a coal sample mixture; treating the coal sample mixed liquid with microwaves to obtain a treated mixed liquid; The treated mixed liquid is transferred to a flotation tank, and after flotation, filtration and drying, a coal sample with mercury, lead and fluorine removed is obtained.
2. The collaborative flotation method for removing mercury, lead and fluorine from coal according to claim 1, characterized in that The alcohol treatment agent is ethanol.
3. The collaborative flotation method for removing mercury, lead and fluorine from coal according to claim 2, characterized in that The oxidant is hydrogen peroxide.
4. The collaborative flotation method for removing mercury, lead and fluorine from coal according to claim 3, characterized in that For every ton of coal, add 300L to 1000L of ethanol, 300L to 1200L of hydrogen peroxide and 20m³ to 30m³ of water.
5. The collaborative flotation method for removing mercury, lead and fluorine from coal according to any one of claims 1 to 4, characterized in that The particle size of the coal samples ranged from 0.1 mm to 0.2 mm.
6. The collaborative flotation method for removing mercury, lead and fluorine from coal according to any one of claims 1 to 5, characterized in that The microwave treatment is carried out under stirring at a temperature of 30°C to 50°C and a microwave power density of 12000 W / m 2 Up to 25000W / m 2 , the processing time is 5min to 10min.
7. The collaborative flotation method for removing mercury, lead and fluorine from coal according to claim 6, characterized in that The stirring speed is 500 rpm to 1000 rpm.
8. The collaborative flotation method for removing mercury, lead and fluorine from coal according to any one of claims 1 to 7, characterized in that Flotation is to aerate the flotation tank and add collectors and frothers for flotation.
9. The collaborative flotation method for removing mercury, lead and fluorine from coal according to claim 8, characterized in that The collector is kerosene, and the amount of collector added is 1kg to 1.5kg per ton of coal sample mixture.
10. The collaborative flotation method for removing mercury, lead and fluorine from coal according to claim 8 or 9, characterized in that The foaming agent is octanol, and the amount of foaming agent added is 100g to 150g per 1 ton of coal sample mixture.