Method for removing sulfur, mercury and ash in bituminous coal by using chlorine saline soil

Abstract

The invention relates to the technical field of coal processing, in particular to a method for removing sulfur, mercury and ash in bituminous coal by using chlorine salinized soil, which comprises the following steps of: 1, mixing the bituminous coal, the chlorine salinized soil and water in required amount to obtain a bituminous coal mixed solution; 2, carrying out electrolytic treatment on the bituminous coal mixed solution under ultrasonic and stirring conditions; and step 3, transferring the bituminous coal mixed solution subjected to electrolysis treatment into a flotation tank, and carrying out flotation to obtain the bituminous coal without sulfur, mercury and ash. The chlorine salinized soil acts on the bituminous coal, ultrasonic electrolysis and flotation assistance are combined, sulfur, mercury and ash in the bituminous coal are efficiently removed, the method is non-toxic, green and environmentally friendly, the reaction condition is mild, the reaction time is short, the process is simple, the method has popularization value, efficient conversion and clean utilization of coal are promoted, and meanwhile comprehensive utilization of the chlorine salinized soil is facilitated.

Description

Technical Field

[0001] The invention relates to the technical field of coal processing, and is a method for removing sulfur, mercury and ash from bituminous coal by utilizing chloride-salinated soil. Background Art

[0002] The environmental impact of coal mining and conversion cannot be ignored, especially the pollution to the atmospheric environment. Sulfur, mercury and ash in coal form acid rain, haze, smoke and dust when burned, which poses a serious challenge to the natural ecology and human health. In view of this, the research and development and promotion of more environmentally friendly and efficient coal clean processing and utilization technologies to reduce the impact on the environment has become an urgent issue to be solved.

[0003] Studies have shown that there are a variety of physical, biological and chemical methods that can be used for desulfurization and ash reduction, such as mineral processing, biological desulfurization, the use of chemical solvents, pyrolysis and hydrodesulfurization. However, these conventional desulfurization and ash reduction methods require heavy equipment, toxic chemicals, high pressure and high temperature, and there are many disadvantages in the economic benefits of using these methods. The first is the cost and economic benefit issue: although many electrochemical desulfurization methods such as calcium oxide method and sodium hydroxide method can effectively remove sulfur, their processes are complicated and costly, involving the use of a large number of chemical reagents, which increases the processing cost and constitutes an economic burden for large-scale applications. The second is the limitation of treatment efficiency: physical desulfurization methods such as gravity separation, flotation, magnetic separation, etc. have a good removal effect on inorganic sulfur, but the removal efficiency of organic sulfur is limited, which limits the overall sulfur reduction rate. The third is environmental impact: some desulfurization technologies may cause secondary pollution. For example, a large amount of coal sludge water generated during wet coal preparation needs to be treated. If it is not properly treated, it will pollute water resources, especially for arid and water-scarce areas. This is a major problem. At the same time, some chemical desulfurization methods may use harmful chemicals, which can remove sulfur but bring new environmental risks. Fourth, technical complexity: biological desulfurization and some chemical desulfurization technologies have complex production processes and long cycles, are not easy to respond to market changes quickly, and require high skills from operators. Fifth, equipment and maintenance: some desulfurization equipment requires large investments, and has high operating and maintenance costs. For example, wet sorting systems require large equipment to treat coal slurry water, and the operation and maintenance of these equipment require high costs. Sixth, applicability limitations: some methods are limited by coal quality characteristics. For example, fine-grained pyrite sulfides are difficult to effectively remove through conventional flotation, and there is a risk of corrosion to the equipment.

[0004] The current raw coal desulfurization technology includes physical, chemical and biological treatment technologies. Although chemical and biological coal preparation methods can remove inorganic sulfur and organic sulfur from coal at the same time, it is difficult to achieve industrialization in the short term due to factors such as complex production processes, long production cycles and easy secondary pollution. Physical coal preparation methods include heavy media, jigging, flotation, electrostatic separation, magnetic separation, etc. Among them, wet separation methods such as gravity separation and flotation mainly remove inorganic sulfur, mercury and ash from coal. Although they have been applied to a certain extent, the pyrite in my country's coal is mostly fine-grained, and most of the sulfur in coal is contaminated by carbon, resulting in poor desulfurization effects of the current common gravity separation and flotation methods. In addition, these methods, including wet magnetic separation, require a huge coal slurry water treatment system. However, more than 2 / 3 of my country's coal resources are distributed in the arid and water-scarce northwest and north China regions, making it difficult to use these water-intensive separation methods. In addition, their investment and operating costs are very high, which is easy to cause new environmental pollution, and it is impossible to achieve online separation in front of the furnace, so they have not been widely used. Summary of the invention

[0005] The present invention provides a method for removing sulfur, mercury and ash from bituminous coal by using chloride-salinated soil, which overcomes the deficiencies of the above-mentioned prior art and can effectively solve the problems of existing bituminous coal desulfurization, high mercury cost and easy environmental pollution.

[0006] The technical solution of the present invention is achieved by the following measures: A method for removing sulfur, mercury and ash from bituminous coal using chloride-salted soil is carried out according to the following steps:

[0007] In the first step, a required amount of bituminous coal, chlorine-salinated soil and water are mixed to obtain a bituminous coal mixed liquid;

[0008] In the second step, the bituminous coal mixture is electrolyzed under ultrasound and stirring;

[0009] The third step is to transfer the bituminous coal mixture after electrolysis treatment into a flotation tank. After flotation, the bituminous coal is removed of sulfur, mercury, and ash.

[0010] The following are further optimizations and / or improvements to the above technical solutions:

[0011] Among the soil ion components of the above chloride saline soil, Na + , K + 90% or more of the total cations, Cl - It accounts for 80% or more of the total anions.

[0012] The mass ratio of the above-mentioned bituminous coal to chloride-saline soil is 1:0.25 to 1:1.25, and the mass ratio of the total amount of bituminous coal, chloride-saline soil and water is 2.5 to 5:100.

[0013] In the first step above, the particle size (diameter) of the bituminous coal and the chloride-saline soil is less than or equal to 0.2 mm.

[0014] In the second step, the ultrasonic power is 350W to 500W, and the stirring speed is 100rpm to 400rpm.

[0015] In the second step above, the electrode used for electrolysis is a platinum electrode.

[0016] In the above second step, electrolysis is carried out at 20° C. to 70° C., the electrolysis voltage is 10 V to 60 V, and the electrolysis time is 10 min to 80 min.

[0017] In the above third step, flotation includes the following steps:

[0018] transferring the bituminous coal mixture after electrolysis treatment into a flotation tank;

[0019] Aeration is added to the flotation tank, and collector and frother are added for flotation;

[0020] The bituminous coal mixed liquid after flotation is filtered and dried to obtain bituminous coal with sulfur, mercury and ash removed.

[0021] The collector is kerosene, and the amount of collector added is 1kg to 1.5kg per 1t of bituminous coal mixture.

[0022] The foaming agent is 2-octanol, and the amount of the foaming agent added is 100g to 150g per 1t of bituminous coal mixed liquid.

[0023] The present invention provides a method for removing sulfur, mercury and ash from bituminous coal by using chloride-salinated soil. The method uses chloride-salinated soil to act on the bituminous coal, and is combined with ultrasonic electrolysis and flotation to efficiently remove sulfur, mercury and ash from the bituminous coal. The method is non-toxic, green and environmentally friendly, has mild reaction conditions, short reaction time, simple process, has promotion value, promotes efficient conversion and clean utilization of coal, and is also beneficial to the comprehensive utilization of chloride-salinated soil. DETAILED DESCRIPTION

[0024] The present invention is not limited by the following embodiments, and the specific implementation method can be determined according to the technical scheme of the present invention and the actual situation. Unless otherwise specified, the various chemical reagents and chemicals mentioned in the present invention are all chemical reagents and chemicals known and used in the prior art; unless otherwise specified, the percentages in the present invention are all mass percentages; unless otherwise specified, the solutions in the present invention are all aqueous solutions with water as the solvent, for example, hydrochloric acid solution is a hydrochloric acid aqueous solution; the normal temperature and room temperature in the present invention generally refer to a temperature of 15°C to 25°C, and are generally defined as 25°C.

[0025] The present invention will be further described below in conjunction with embodiments:

[0026] Example 1: The method for removing sulfur, mercury and ash from bituminous coal using chloride-salted soil is carried out according to the following steps:

[0027] In the first step, a required amount of bituminous coal, chlorine-salinated soil and water are mixed to obtain a bituminous coal mixed liquid;

[0028] In the second step, the bituminous coal mixture is electrolyzed under ultrasound and stirring;

[0029] The third step is to transfer the bituminous coal mixture after electrolysis treatment into a flotation tank. After flotation, the bituminous coal is removed of sulfur, mercury, and ash.

[0030] Example 2: As an optimization of the above example, the soil ion composition of chloride saline soil is Na + , K + 90% or more of the total cations, Cl - It accounts for 80% or more of the total anions.

[0031] Example 3: As an optimization of the above example, the mass ratio of bituminous coal to chloride-saline soil is 1:0.25 to 1:1.25, and the mass ratio of the total amount of bituminous coal and chloride-saline soil to water is 2.5 to 5:100.

[0032] Example 4: As an optimization of the above example, in the first step, the particle size (diameter) of the bituminous coal and the chloride-saline soil is less than or equal to 0.2 mm.

[0033] Embodiment 5: As an optimization of the above embodiment, in the second step, the ultrasonic power is 350W to 500W, and the stirring speed is 100rpm to 400rpm.

[0034] Example 6: As an optimization of the above example, in the second step, the electrode used for electrolysis is a platinum electrode.

[0035] Example 7: As an optimization of the above example, in the second step, electrolysis is carried out at 20°C to 70°C, the electrolysis voltage is 10V to 60V, and the electrolysis time is 10min to 80min.

[0036] Embodiment 8: As an optimization of the above embodiment, in the third step, flotation includes the following steps:

[0037] transferring the bituminous coal mixture after electrolysis treatment into a flotation tank;

[0038] Aeration is added to the flotation tank, and collector and frother are added for flotation;

[0039] The bituminous coal mixed liquid after flotation is filtered and dried to obtain bituminous coal with sulfur, mercury and ash removed.

[0040] Example 9: As an optimization of the above example, the collector is kerosene, and the amount of the collector added is 1 kg to 1.5 kg per 1 t of bituminous coal mixture.

[0041] Example 10: 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 1t of bituminous coal mixture.

[0042] There are differences in the ultrasonic electrochemical enhanced flotation desulfurization of coal under different electrolytes. While considering that the electrolyte can improve the desulfurization and ash reduction effect, the cost of the electrolyte is also worth considering. Too expensive electrolysis is not conducive to industrial production. The present invention adopts clean and economical chloride saline soil (Na + , K + Accounting for more than 90% of the total cations, CI - The anions account for more than 95% of the total amount. The ultrasonic electrochemical flotation of bituminous coal is carried out as an electrolyte. During the electrolysis process, the chloride-salinated soil effectively promotes the electrolysis and improves the desulfurization, mercury and ash content of the coal.

[0043] In the present invention, chloride saline soil is selected as the electrolyte, and the raw material comes from the undeveloped saline-alkali soil in the southern Xinjiang region of the Xinjiang Uygur Autonomous Region. Utilizing the salts in the chloride saline soil as electrolyte will greatly improve the utilization rate of the chloride saline soil and promote the effective development and utilization of the chloride saline soil.

[0044] As shown in the following chemical formulas 1 to 7, during the reaction, the CI on the anode surface - Loss of charge (chemical formula 1), generating oxidized groups such as hypochlorite anions, hypochlorite anions partially decomposed into active functional groups such as O2 (chemical formula 4), O2 in the chemical equation can oxidize pyrite sulfur and part of organic sulfur into soluble sulfate or sulfonic acid anions. Due to the electrochemical oxidation on the anode (chemical formulas 5 and 6), it has a good effect on sulfur removal.

[0045] anode:

[0046] 2Cl - =Cl2↑+2e

[0047] Formula 1

[0048] Cl2+H2O→OCl - ↑+Cl -

[0049] Formula 2

[0050] OCl - +FeS2→FeSO4+S+Cl -

[0051] Formula 3

[0052] OCl - →O2↑+HCl

[0053] Formula 4

[0054]

[0055] cathode:

[0056]

[0057] Embodiment 11:

[0058] The bituminous coal treated in this embodiment is Kuche clean coal, and the chloride-saline soil used is from Aksu area of ​​Xinjiang Uygur Autonomous Region. The soil ion composition of the chloride-saline soil is Na + , K + 90% to 96% of the total cations, Cl - It accounts for 85% to 98% of the total anions.

[0059] The specific operation of the method for removing sulfur, mercury and ash from bituminous coal by using chloride saline soil is as follows:

[0060] The crushed bituminous coal and chloride-salinated soil were added into the electrolytic cell in a mass ratio of 2:1, and the required amount of distilled water was added into the electrolytic cell to prepare a 40g / kg bituminous coal mixed solution. The mixture was electrolyzed under ultrasound and stirring, with an ultrasonic power of 400W, stirring at 300rpm, an electrolysis time of 24min, an electrolysis voltage of 40V, and an electrolysis temperature of 60°C.

[0061] Place the electrolyzed bituminous coal mixture into the flotation tank, start and debug the unit gasification volume to 0.25m 3 / (m 2 ·min); turn on the flotation machine switch and stir for 2 minutes, then add 1000g / t of kerosene (kerosene: bituminous coal mixture) to the liquid surface of the bituminous coal mixture; 1 minute later, add 120g / t of 2-octanol (kerosene: bituminous coal mixture), a foaming agent, to the liquid surface of the bituminous coal mixture; after stirring, wash the particles deposited at the bottom of the flotation tank into the tail coal container, filter the coal slurry in the flotation tank to obtain filter residue, and dry the filter residue to obtain bituminous coal with sulfur, mercury and ash removed.

[0062] The bituminous coal from which sulfur, mercury, and ash were removed in this embodiment was tested (test data is shown in Table 1), and the sulfur reduction rate reached 55.96%, the ash reduction rate was 61.36%, and the mercury removal rate was 85.07%.

[0063] Embodiment 12:

[0064] The bituminous coal treated in this embodiment is Aksu bituminous coal, and the chloride-saline soil used is from Aksu area. The soil ion composition of the chloride-saline soil is Na + , K+ 91% to 96% of the total cations, CI - It accounts for 92% to 98% of the total anions.

[0065] The crushed Aksu anthracite and chloride-salinated soil were added into the electrolytic cell in a mass ratio of 4:3. The required amount of distilled water was added into the electrolytic cell to prepare a 40g / kg bituminous coal mixed solution. The mixture was electrolyzed under ultrasound and stirring. The ultrasonic power was 400W, the stirring speed was 300rpm, the electrolysis time was 24min, the electrolysis voltage was 40V, and the electrolysis temperature was 40℃.

[0066] Place the electrolyzed bituminous coal mixture into the flotation tank, start and debug the unit gasification volume to 0.25m 3 / (m 2 ·min); turn on the flotation machine switch and stir for 2 minutes, then add 1000g / t of kerosene (kerosene: bituminous coal mixture) to the liquid surface of the bituminous coal mixture; 1 minute later, add 120g / t of 2-octanol (2-octanol: bituminous coal mixture), a foaming agent, to the liquid surface of the bituminous coal mixture; after stirring, wash the particles deposited at the bottom of the flotation tank into the tail coal container, filter the coal slurry in the flotation tank to obtain filter residue, and dry the filter residue to obtain bituminous coal with sulfur, mercury and ash removed.

[0067] The bituminous coal from which sulfur, mercury, and ash were removed in this embodiment was tested (test data is shown in Table 1), and the sulfur reduction rate reached 46.51%, the ash reduction rate was 44.31%, and the mercury removal rate was 67.84%.

[0068] Embodiment 13:

[0069] The bituminous coal treated in this embodiment is Alaer Jiutuan mixed coal, and the chloride-saline soil used is from Aksu area. The soil ion composition of the chloride-saline soil is Na + , K + 92% to 95% of the total cations, CI - It accounts for 82% to 95% of the total anions.

[0070] The crushed Alar Jiutuan miscellaneous coal and chloride-saline soil were added into the electrolytic cell in a mass ratio of 1:1. The required amount of distilled water was added into the electrolytic cell to prepare a 45g / kg bituminous coal mixture. The mixture was electrolyzed under ultrasound and stirring. The ultrasonic power was 400W, the stirring speed was 300rpm, the electrolysis time was 18min, the electrolysis voltage was 40V, and the electrolysis temperature was 50℃.

[0071] Place the electrolyzed bituminous coal mixture into the flotation tank, start and debug the unit gasification volume to 0.25m 3 / (m 2·min); turn on the flotation machine switch and stir for 2 minutes, then add 1000g / t of kerosene (kerosene: bituminous coal mixture) to the liquid surface of the bituminous coal mixture; 1 minute later, add 120g / t of 2-octanol (kerosene: bituminous coal mixture), a foaming agent, to the liquid surface of the bituminous coal mixture; after stirring, wash the particles deposited at the bottom of the flotation tank into the tail coal container, filter the coal slurry in the flotation tank to obtain filter residue, and dry the filter residue to obtain bituminous coal with sulfur, mercury and ash removed.

[0072] The bituminous coal from which sulfur, mercury, and ash were removed in this embodiment was tested (test data is shown in Table 1), and the sulfur reduction rate reached 55.40%, the ash reduction rate was 57.10%, and the mercury removal rate was 79.17%.

[0073] Embodiment 14:

[0074] The bituminous coal treated in this embodiment is Baicheng bituminous coal, and the chloride-saline soil used is from the undeveloped saline-alkali land in Aksu area. The soil ion composition of the chloride-saline soil is Na + , K + 93% to 96% of the total cations, CI - It accounts for 88% to 95% of the total anions.

[0075] The crushed Baicheng bituminous coal and chloride-saline soil were added into the electrolytic cell in a mass ratio of 2:1. The required amount of distilled water was added into the electrolytic cell to prepare a 50g / kg bituminous coal mixed solution. The mixture was electrolyzed under ultrasound and stirring. The ultrasonic power was 400W, the stirring speed was 300rpm, the electrolysis time was 24min, the electrolysis voltage was 40V, and the electrolysis temperature was 60℃.

[0076] Place the electrolyzed bituminous coal mixture into the flotation tank, start and debug the unit gasification volume to 0.25m 3 / (m 2 ·min); turn on the flotation machine switch and stir for 2 minutes, then add 1000g / t of kerosene (kerosene: bituminous coal mixture) to the liquid surface of the bituminous coal mixture; 1 minute later, add 120g / t of 2-octanol (kerosene: bituminous coal mixture), a foaming agent, to the liquid surface of the bituminous coal mixture; after stirring, wash the particles deposited at the bottom of the flotation tank into the tail coal container, filter the coal slurry in the flotation tank to obtain filter residue, and dry the filter residue to obtain bituminous coal with sulfur, mercury and ash removed.

[0077] The bituminous coal from which sulfur, mercury, and ash were removed in this embodiment was tested (test data is shown in Table 1), and the sulfur reduction rate reached 42.95%, the ash reduction rate was 44.46%, and the mercury removal rate was 66.98%.

[0078] Embodiment 15:

[0079] The bituminous coal treated in this embodiment is the household coal of Wensu, and the chloride-salted soil used is from the undeveloped saline-alkali land in Aksu area. The soil ion composition of the chloride-salted soil is Na + , K + 93% to 96% of the total cations, CI - It accounts for 89% to 98% of the total anions.

[0080] The crushed Wensu household coal and chlorine-salinated soil were added into the electrolytic cell in a mass ratio of 2:1. The required amount of distilled water was added into the electrolytic cell to prepare a 40g / kg bituminous coal mixture. The mixture was electrolyzed under ultrasound and stirring. The ultrasonic power was 400W, the stirring speed was 300rpm, the electrolysis time was 24min, the electrolysis voltage was 40V, and the electrolysis temperature was 60℃.

[0081] Place the electrolyzed bituminous coal mixture into the flotation tank, start and debug the unit gasification volume to 0.25m 3 / (m 2 ·min); turn on the flotation machine switch and stir for 2 minutes, then add 1000g / t of kerosene (kerosene: bituminous coal mixture) to the liquid surface of the bituminous coal mixture; 1 minute later, add 120g / t of 2-octanol (kerosene: bituminous coal mixture), a foaming agent, to the liquid surface of the bituminous coal mixture; after stirring, wash the particles deposited at the bottom of the flotation tank into the tail coal container, filter the coal slurry in the flotation tank to obtain filter residue, and dry the filter residue to obtain bituminous coal with sulfur, mercury and ash removed.

[0082] The ultrasonic electrolysis time was 24 min, the ultrasonic electrolysis voltage was 40 V, and the ultrasonic electrolysis temperature was 60 °C.

[0083] The bituminous coal from which sulfur, mercury, and ash were removed in this embodiment was tested (test data is shown in Table 1), and the sulfur reduction rate reached 33.48%, the ash reduction rate was 33.29%, and the mercury removal rate was 92.40%.

[0084] Embodiment 16:

[0085] The bituminous coal treated in this embodiment is Jundetu raw coal, and the chloride-saline soil used is from the undeveloped saline-alkali land in Aksu area. The soil ion composition of the chloride-saline soil is Na + , K + 93% to 96% of the total cations, CI - It accounts for 87% to 98% of the total anions.

[0086] The crushed Jundetu raw coal and chloride-salinated soil were added into the electrolytic cell in a mass ratio of 4:3. The required amount of distilled water was added into the electrolytic cell to prepare a 40g / kg bituminous coal mixed liquid. The mixture was electrolyzed under ultrasound and stirring. The ultrasonic power was 400W, the stirring speed was 300rpm, the electrolysis time was 24min, the electrolysis voltage was 30V, and the electrolysis temperature was 60℃.

[0087] Place the electrolyzed bituminous coal mixture into the flotation tank, start and debug the unit gasification volume to 0.25m 3 / (m 2 ·min); turn on the flotation machine switch and stir for 2 minutes, then add 1000g / t of kerosene (kerosene: bituminous coal mixture) to the liquid surface of the bituminous coal mixture; 1 minute later, add 120g / t of 2-octanol (kerosene: bituminous coal mixture), a foaming agent, to the liquid surface of the bituminous coal mixture; after stirring, wash the particles deposited at the bottom of the flotation tank into the tail coal container, filter the coal slurry in the flotation tank to obtain filter residue, and dry the filter residue to obtain bituminous coal with sulfur, mercury and ash removed.

[0088] The bituminous coal from which sulfur, mercury, and ash were removed in this embodiment was tested (test data is shown in Table 1), and the sulfur reduction rate reached 36.16%, the ash reduction rate was 26.30%, and the mercury removal rate was 75.80%.

[0089] Embodiment 17:

[0090] The bituminous coal treated in this embodiment is Pingyao coal 2.0, and the chloride-saline soil used is from the undeveloped saline-alkali land in Aksu area. The soil ion composition of the chloride-saline soil is Na + , K + 90% to 96% of the total cations, CI - It accounts for 82% to 98% of the total anions.

[0091] The crushed Pingyao coal 2.0 and chloride-saline soil were added into the electrolytic cell in a mass ratio of 4:1, and the required amount of distilled water was added into the electrolytic cell to prepare a 40g / kg bituminous coal mixed liquid. The mixture was electrolyzed under ultrasound and stirring, with an ultrasonic power of 400W, stirring at 300rpm, an electrolysis time of 30min, an electrolysis voltage of 40V, and an electrolysis temperature of 50°C.

[0092] Place the electrolyzed bituminous coal mixture into the flotation tank, start and debug the unit gasification volume to 0.25m 3 / (m 2 ·min); turn on the flotation machine switch and stir for 2 minutes, then add 1000g / t of kerosene (kerosene: bituminous coal mixture) to the liquid surface of the bituminous coal mixture; 1 minute later, add 120g / t of 2-octanol (kerosene: bituminous coal mixture), a foaming agent, to the liquid surface of the bituminous coal mixture; after stirring, wash the particles deposited at the bottom of the flotation tank into the tail coal container, filter the coal slurry in the flotation tank to obtain filter residue, and dry the filter residue to obtain bituminous coal with sulfur, mercury and ash removed.

[0093] The bituminous coal from which sulfur, mercury, and ash were removed in this embodiment was tested (test data is shown in Table 1), and the sulfur reduction rate reached 20.45%, the ash reduction rate was 23.53%, and the mercury removal rate was 60.94%.

[0094] Embodiment 18:

[0095] The bituminous coal treated in this embodiment is Pingyao coal 3.0, and the chloride-saline soil used is from the undeveloped saline-alkali land in Aksu area. The soil ion composition of the chloride-saline soil is Na + , K + 92% to 96% of the total cations, CI - It accounts for 90% to 98% of the total anions.

[0096] The crushed Pingyao coal 3.0 and chloride-saline soil were added into the electrolytic cell in a mass ratio of 4:3, and the required amount of distilled water was added into the electrolytic cell to prepare a 40g / kg bituminous coal mixed liquid. The mixture was electrolyzed under ultrasound and stirring, with an ultrasonic power of 400W, stirring at 300rpm, an electrolysis time of 30min, an electrolysis voltage of 40V, and an electrolysis temperature of 50°C.

[0097] Place the electrolyzed bituminous coal mixture into the flotation tank, start and debug the unit gasification volume to 0.25m 3 / (m 2 ·min); turn on the flotation machine switch and stir for 2 minutes, then add 1000g / t of kerosene (kerosene: bituminous coal mixture) to the liquid surface of the bituminous coal mixture; 1 minute later, add 120g / t of 2-octanol (kerosene: bituminous coal mixture), a foaming agent, to the liquid surface of the bituminous coal mixture; after stirring, wash the particles deposited at the bottom of the flotation tank into the tail coal container, filter the coal slurry in the flotation tank to obtain filter residue, and dry the filter residue to obtain bituminous coal with sulfur, mercury and ash removed.

[0098] The bituminous coal from which sulfur, mercury, and ash were removed in this embodiment was tested (test data is shown in Table 1), and the sulfur reduction rate reached 29.77%, the ash reduction rate was 26.32%, and the mercury removal rate was 52.33%.

[0099] Embodiment 19:

[0100] The bituminous coal treated in this embodiment is raw coal from Bazhou, and the chloride-saline soil used is from the undeveloped saline-alkali land in Aksu area. The soil ion composition of the chloride-saline soil is Na + , K + 90% to 96% of the total cations, CI - It accounts for 82% to 93% of the total anions.

[0101] The crushed Bazhou raw coal and chloride-salinated soil were added into the electrolytic cell in a mass ratio of 4:1. The required amount of distilled water was added into the electrolytic cell to prepare a 40g / kg bituminous coal mixture. The mixture was electrolyzed under ultrasound and stirring. The ultrasonic power was 400W, the stirring speed was 300rpm, the electrolysis time was 24min, the electrolysis voltage was 30V, and the electrolysis temperature was 60℃.

[0102] Place the electrolyzed bituminous coal mixture into the flotation tank, start and debug the unit gasification volume to 0.25m 3 / (m 2 ·min); turn on the flotation machine switch and stir for 2 minutes, then add 1000g / t of kerosene (kerosene: bituminous coal mixture) to the liquid surface of the bituminous coal mixture; 1 minute later, add 120g / t of 2-octanol (kerosene: bituminous coal mixture), a foaming agent, to the liquid surface of the bituminous coal mixture; after stirring, wash the particles deposited at the bottom of the flotation tank into the tail coal container, filter the coal slurry in the flotation tank to obtain filter residue, and dry the filter residue to obtain bituminous coal with sulfur, mercury and ash removed.

[0103] The bituminous coal from which sulfur, mercury, and ash were removed in this embodiment was tested (test data is shown in Table 1), and the sulfur reduction rate reached 38.52%, the ash reduction rate was 7.28%, and the mercury removal rate was 89.13%.

[0104] Comparative Example 1: The difference from Example 16 is that no ultrasonic treatment is performed. The comparison results are shown in Table 2.

[0105] Comparative Example 2: The difference from Example 11 is that the filtrate of chloride-saline soil is used to replace the chloride-saline soil; wherein the filtrate of chloride-saline soil is the leachate of chloride-saline soil in the same amount as that in Example 16. The comparison results are shown in Table 3.

[0106] Comparative Example 3: The difference from Example 12 is that the electrolysis temperature was 20°C and 30°C respectively for two experiments. The comparison results are shown in Table 4.

[0107] It can be seen from the above embodiments and comparative examples that, compared with simple physical or chemical coal cleaning technologies, the method of removing sulfur, mercury and ash from bituminous coal using chloride-salted soil of the present invention has mild reaction conditions, simple operation, and has advantages in using ultrasonic electrochemical flotation to assist in desulfurization, mercury and ash. The present invention has the following advantages:

[0108] (1) The present invention proposes a new method for comprehensive utilization of local low-value resources, and a new method for removing harmful element S from nine types of bituminous coal samples using chloride-salted soil. Experimental studies have shown that this method is not only feasible, but also has a significant and effective removal effect. It has the advantages of high desulfurization rate, low operating cost, environmental friendliness, and easy engineering implementation.

[0109] (2) The present invention proposes a low-cost desulfurization process route. Based on the necessary theoretical research such as thermodynamic analysis and reaction mechanism exploration, the optimal desulfurization formula and technical route are designed by adding electrode electrolysis in view of the characteristics that raw coal desulfurization is a redox reaction.

[0110] (3) The present invention establishes a flotation scheme using ultrasonic enhancement. The cavitation effect of ultrasonic waves can produce a strong local high-pressure and high-temperature environment, which promotes the cracking of sulfide minerals on the surface of coal particles and enhances the separation effect of coal and sulfide minerals. At the same time, the mechanical vibration of ultrasonic waves helps to disperse fine particles, increase the contact opportunities between coal particles and bubbles, improve the selectivity and recovery rate of flotation, and promote the stripping of ash and some harmful elements it carries.

[0111] (4) Chloride-saline soil can remove other harmful components when treating raw coal. Chloride-saline soil, as an electrolyte source for removing sulfur from coal, also shows significant effects in removing mercury and ash. In the study of using chloride-saline soil to treat raw coal, it was found that the redox reaction during the electrolysis process can also specifically destroy the chemical bonds of Hg compounds in coal. As shown in Example 11, not only can the desulfurization rate reach 55.96%, but the ash reduction rate is 61.36%, the mercury removal rate is 85.07%, and the moisture and volatile matter of the product clean coal are also lower than those of the raw coal (see Table 5 for the comparison results of Examples 11 to 19).

[0112] (5) The technology of the present invention can also reduce the process energy consumption and equipment corrosion prevention of the entire industrial chain process of coal conversion and utilization. The traditional coal utilization process is characterized by high temperature and high pressure, while the current desulfurization technology is completed at a lower temperature and pressure. This will inevitably result in the process route of coal conversion to first reduce pressure, cool down, then desulfurize, and then increase pressure and temperature, which will inevitably lead to the loss of effective energy, corrosion of equipment and pipelines and other adverse conditions.

[0113] In summary, the present invention provides a method for removing sulfur, mercury and ash from bituminous coal by using chloride-salted soil. The method combines ultrasonic electrolysis and flotation to assist the removal of sulfur, mercury and ash from bituminous coal by using chloride-salted soil on the coal. The desulfurization method is non-toxic, green, environmentally friendly, economical and practical, and is not prone to secondary pollution during the desulfurization process and has no corrosive effect on equipment. The reaction conditions are mild, the reaction time is short, the process is simple, and the method has promotion value.

[0114] The above technical features respectively constitute various embodiments of the present invention, which have strong adaptability and implementation effect. Non-essential technical features can be added or reduced according to actual needs to meet the requirements of different situations.

[0115] Table 1

[0116]

[0117] Table 2

[0118] Sulfur content before treatment (%) Ash before treatment (%) Sulfur content after treatment (%) Ash after treatment (%) Example 16 0.3722 40.99 0.2376 30.21 Comparative Example 1 0.3722 40.99 0.3514 34.56

[0119] Table 3

[0120]

[0121] Table 4

[0122]

[0123] Table 5

[0124]

Claims

1. A method for removing sulfur, mercury and ash from bituminous coal using chloride-salinated soil, characterized in that Follow these steps: In the first step, a required amount of bituminous coal, chlorine-salinated soil and water are mixed to obtain a bituminous coal mixed liquid; In the second step, the bituminous coal mixture is electrolyzed under ultrasound and stirring; The third step is to transfer the bituminous coal mixture after electrolysis treatment into a flotation tank. After flotation, the bituminous coal is removed of sulfur, mercury, and ash.

2. The method for removing sulfur, mercury and ash from bituminous coal using chloride-salinated soil according to claim 1, characterized in that Among the soil ion components of chloride saline soil, Na + , K + 90% or more of the total cations, Cl - It accounts for 80% or more of the total anions.

3. The method for removing sulfur, mercury and ash from bituminous coal using chloride-salinated soil according to claim 1 or 2, characterized in that The mass ratio of bituminous coal to chloride-saline soil is 1:0.25 to 1:1.25, and the mass ratio of the total amount of bituminous coal and chloride-saline soil to water is 2.5 to 5:

100.

4. The method for removing sulfur, mercury and ash from bituminous coal using chloride-salinated soil according to any one of claims 1 to 3, characterized in that In the first step, the particle size of the bituminous coal and the chloride-saline soil is less than or equal to 0.2 mm.

5. The method for removing sulfur, mercury and ash from bituminous coal using chloride-salinated soil according to any one of claims 1 to 4, characterized in that In the second step, the ultrasonic power is 350W to 500W, and the stirring speed is 100rpm to 400rpm.

6. The method for removing sulfur, mercury and ash from bituminous coal using chloride-salinated soil according to any one of claims 1 to 5, characterized in that In the second step, the electrodes used for electrolysis are platinum electrodes.

7. The method for removing sulfur, mercury and ash from bituminous coal using chloride-salinated soil according to any one of claims 1 to 6, characterized in that In the second step, electrolysis is carried out at 20° C. to 70° C., the electrolysis voltage is 10 V to 60 V, and the electrolysis time is 10 min to 80 min.

8. The method for removing sulfur, mercury and ash from bituminous coal using chloride-salinated soil according to any one of claims 1 to 7, characterized in that In the third step, flotation includes the following steps: transferring the bituminous coal mixture after electrolysis treatment into a flotation tank; Aeration is added to the flotation tank, and collector and frother are added for flotation; The bituminous coal mixed liquid after flotation is filtered and dried to obtain bituminous coal with sulfur, mercury and ash removed.

9. The method for removing sulfur, mercury and ash from bituminous coal using chloride-salted soil according to claim 8, characterized in that The collector is kerosene, and the amount of collector added is 1kg to 1.5kg per 1t of bituminous coal mixture.

10. The method for removing sulfur, mercury and ash from bituminous coal using chloride-salinated soil according to claim 8 or 9, characterized in that The foaming agent is 2-octanol, and the amount of the foaming agent added is 100g to 150g per 1t of bituminous coal mixed liquid.

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