Method for recovering low-ash high-adsorption-capacity carbon from coal gasification fine slag

Abstract

The invention discloses a method for recovering low-ash high-adsorption-capacity carbon from fine coal gasification slag, which comprises the following steps: 1) pulping the fine coal gasification slag to obtain fine slag ore pulp; and (2) the fine slag ore pulp is subjected to gravity separation, and light-component ore pulp is collected. According to the method, the residual carbon in the coal gasification fine slag is recycled by adopting a pure physical reselection technical means, consumption of a large number of chemical agents in the flotation process is avoided, and meanwhile the high recycling rate can be achieved. Because inorganic mineral components in the coal gasification fine slag are mainly metal oxides and silicates, most inorganic mineral components closely symbiotic in residual carbon can be removed in an acid pickling mode, the ash content of the residual carbon is further reduced, meanwhile, the pore structure of the residual carbon is opened, and surface active sites are optimized; therefore, the coal gasification fine slag can be used as an auxiliary adsorption material with better performance or a precursor of activated carbon, and the aims of recycling and high-value utilization of residual carbon in the coal gasification fine slag are fulfilled.

Description

Technical Field

[0001] The invention belongs to the technical field of resource utilization of waste products, and in particular relates to a method for recovering low-ash and high-adsorption carbon from coal gasification fine slag. Background Art

[0002] With the expansion of the scale of modern coal chemical industry, the stockpile of coal gasification slag continues to increase. At present, the research on the resource treatment method of coal gasification slag is not mature, and most of the gasification slag can only be treated by open-air stacking or landfill. A large amount of gasification slag has caused serious waste of land resources. Every 10,000 tons of gasification slag needs to occupy 3,000 square meters of slag storage. At the same time, gasification slag often contains a variety of harmful heavy metals. Long-term storage will cause serious soil and water pollution. Under the action of wind erosion, it will also cause serious air pollution. This series of pollution will eventually lead to damage to human health. The residual carbon and elements such as Si, Al, Ca, and Fe contained in coal gasification slag have high potential for resource utilization. Landfilling coal gasification slag will cause serious waste of resources and have an adverse impact on the sustainable development of coal chemical enterprises.

[0003] At present, the resource utilization of coal gasification slag is reflected in fuel, environmental protection, building materials, etc. The residual carbon contained in the gasification slag determines its potential value as a fuel. Some scholars recover the carbon in the gasification slag by flotation, and divide the gasification slag into two parts: concentrate and tailings. The carbon content of the concentrate is greater than 90%, reaching the index for blending fuel, and the carbon content of the tailings is less than 10%, which meets the national standards for building materials and can be used for filling ditches and building roads, making unburned bricks, etc. However, due to the rich pore structure and high specific surface area of ​​gasification fine slag, it has an extremely high drug absorption capacity, and the flotation separation method is relatively costly; a power plant in Shaanxi Province mixes fine slag (the proportion is less than 5%), but the impact of ash content on boiler efficiency needs to be controlled; in the field of environmental protection, the silicon and calcium elements in the fine slag can improve acidic soil, but pretreatment (such as passivation of heavy metals) and field tests are required to verify safety; a project in Inner Mongolia combines fine slag with organic fertilizer for sandy land improvement, and the pH adjustment effect is significant, but the long-term heavy metal accumulation risk still needs to be monitored; gasification fine slag can also be used for the preparation of high value-added materials, such as catalyst carriers, rubber and plastic fillers, ceramic materials, silicon-based materials, etc.

[0004] Coal gasification slag has rich pore structure and high specific surface area. In the process of coal gasification, water vapor and oxygen as gasifying agents undergo redox reaction with the coal entering the furnace, and the side chains in the coal structure break and decompose, accompanied by the escape of tar, thereby forming a pore structure, which expands as the reaction proceeds. After reaching a certain level, some pore walls collapse, and some structures are selectively activated to produce new pores. The large amount of residual carbon contained in the coal gasification slag is also loose and porous on the surface and mainly has a mesoporous structure. Its specific surface area is second only to industrially prepared activated carbon. It has strong adsorption capacity and is a very potential adsorbent material. The price of coal gasification slag is much lower than that of industrial activated carbon. If the residual carbon in the coal gasification slag can be recovered as an adsorption material for the adsorption of organic matter or heavy metals in other hazardous wastes, it will produce higher economic and environmental benefits. However, due to the dense association of residual carbon and inorganic minerals in coal gasification slag, how to separate residual carbon from inorganic minerals is a major problem currently faced by the industry. The conventional method is to perform flotation after grinding, but the high drug absorption of coal gasification fine slag will lead to excessive reagent consumption and high flotation separation cost. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems in the related art to a certain extent. To this end, the main purpose of the present invention is to provide a method for recovering low-ash and high-adsorption carbon from coal gasification fine slag, to find a new way to utilize the coal gasification fine slag, and to extract valuable products by effectively utilizing these coal gasification wastes to generate greater economic benefits.

[0006] In order to solve the problem of large reagent consumption when recovering residual carbon in coal gasification fine slag by traditional flotation method, the recovery method of the present application adopts a gravity separation method to effectively reduce the amount of chemical reagents used in recovering carbon.

[0007] The residual carbon in the recovered coal gasification fine slag is acid-washed to further reduce the ash content in the recovered carbon and optimize its pore structure and surface adsorption sites to improve its adsorption capacity, so that the recovered carbon can be used as an auxiliary adsorption material for coordinated treatment of other pollutants.

[0008] The objective of the present invention is achieved through the following technical solutions:

[0009] A method for recovering low-ash and high-adsorption carbon from coal gasification fine slag comprises the following steps:

[0010] 1) Slurrying coal gasification fine slag to obtain fine slag slurry;

[0011] 2) The fine slag slurry in step 1) is subjected to gravity separation to obtain a light component, a heavy component and an intermediate component, and the light component slurry is collected.

[0012] The present invention has found that the density of the residual carbon particles in the coal gasification fine slag is generally less than 2.0g / cm 3 , while inorganic mineral particles are often larger than 2.4g / cm 3 The large density difference provides a practical basis for the gravity separation of residual carbon and inorganic minerals. By conducting a secondary gravity separation on the intermediate components of the primary gravity separation, a higher recovery rate of residual carbon in the coal gasification fine slag can be achieved, avoiding the consumption of a large amount of chemical agents in the flotation process.

[0013] In certain specific embodiments, the mass concentration of the fine slag slurry is 15-60wt%.

[0014] Furthermore, the mass concentration of the fine slag slurry is 20-40wt%.

[0015] In some specific embodiments, the pulping process is specifically as follows: adding water to the coal gasification fine slag and stirring it under an impeller stirrer to disperse it evenly, and the stirring time is 2 min-120 min, preferably 5 min-60 min.

[0016] In some specific embodiments, the feed rate in the gravity separation process is 0.5-3 t / h, preferably 1-2 t / h.

[0017] In some specific embodiments, the equipment used in the gravity separation process is a spiral chute, and the opening of the light component discharge port of the spiral chute is 10° to 45°, preferably 15° to 25°.

[0018] In some specific embodiments, in order to improve the recovery rate of carbon, the intermediate components obtained after gravity separation are subjected to multiple gravity separations, and the conditions of the gravity separations are consistent with those of the first gravity separation.

[0019] In the quality improvement method of performing multiple gravity separations, the light components obtained by the multiple gravity separations are collected as a crude product.

[0020] The method for recovering low-ash and high-adsorption capacity carbon from coal gasification fine slag provided in the present application belongs to the same inventive concept as the present invention, and also includes sedimentation filtration of the light component slurry obtained by gravity separation to obtain a filter cake, and then drying and acid-washing and deashing the filter cake to obtain low-ash and high-adsorption capacity carbon.

[0021] In some specific embodiments, the drying process parameters are: temperature of 100-120° C. and time of 12-24 h.

[0022] Furthermore, the drying time is 15-20 hours.

[0023] In some specific embodiments, the process conditions of the acid washing and deashing are: adding dilute hydrochloric acid to the dried filter cake (crude product), stirring the reaction at a speed of 200-300 rpm at a water bath temperature of 60-80°C for 2-4 hours, then standing and cooling, filtering, and then rinsing with deionized water until neutral, and drying.

[0024] In certain specific embodiments, the concentration of the dilute hydrochloric acid is 1-5 mol / L, and the mass ratio of the dilute hydrochloric acid to the filter cake is (1-10):1.

[0025] Furthermore, the concentration of the dilute hydrochloric acid is 2-4 mol / L, and the mass ratio of the dilute hydrochloric acid to the filter cake is (2-8):1.

[0026] In some specific embodiments, the drying process conditions are: temperature of 100-120° C., and drying time of 5-20 h.

[0027] Compared with the prior art, the present invention has at least the following advantages:

[0028] The present invention uses a purely physical gravity separation technique to recover the residual carbon in the coal gasification fine slag, thus avoiding the consumption of a large amount of chemical agents in the flotation process, and also achieving a relatively high recovery rate. Since the inorganic mineral components in the coal gasification fine slag are mainly metal oxides and silicates, the acid washing method can remove most of the inorganic mineral components closely coexisting in the residual carbon, further reducing its ash content, while opening its pore structure and optimizing the surface active sites, so that it can be used as an auxiliary adsorption material with better performance or a precursor of activated carbon, thus achieving the goal of recovering the residual carbon in the coal gasification fine slag and high-value utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the specific embodiments of the present invention, the drawings required for use in the specific embodiments or the description of the prior art will be briefly introduced below.

[0030] Figure 1 The present invention provides a process flow chart of the method for recovering low-ash and high-adsorption carbon from coal gasification fine slag. DETAILED DESCRIPTION

[0031] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. The following embodiments are only illustrative and not restrictive, and the protection scope of the present invention cannot be limited thereto.

[0032] When a certain amount, concentration or other value or parameter is expressed in the form of a range, a preferred range, or a preferred upper and lower numerical limit, it should be understood that it is equivalent to specifically revealing any range by combining any pair of upper range limits or preferred numerical values ​​with any lower range limit or preferred numerical value, regardless of whether the range is specifically disclosed. Unless otherwise indicated, the numerical range values ​​listed herein include the endpoints of the range, and all integers and fractions within the range.

[0033] Unless otherwise indicated, all percentages, parts, ratios, etc. herein are by weight.

[0034] The materials, methods, and examples herein are illustrative and are not to be construed as limiting unless specifically stated.

[0035] In the following examples, the coal gasification fine slag produced by a Shell furnace fed with anthracite of Yunnan Yuntianhua Co., Ltd. is used as raw material. The industrial analysis results of the coal gasification fine slag are shown in the following table:

[0036]

[0037] The test methods used in the following embodiments include:

[0038] The low ash and high adsorption performance of the recovered carbon are reflected by testing the main properties of each test sample respectively; the main properties tested in this application include ash content, specific surface area, pore volume, etc.

[0039] 1) Ash content test;

[0040] The ash content was tested according to the slow ashing method specified in the national standard (GB / T 212-2008). A certain amount of sample was weighed and placed in a muffle furnace, heated to 815±10℃ at a certain speed, ashed and burned until the mass was constant. The mass fraction of the residue to the original sample mass was taken as the ash yield.

[0041] 2) Specific surface area and pore volume test

[0042] The nitrogen adsorption performance of the obtained product was characterized and analyzed using ASAP 2020 physical adsorption instrument, and the specific surface area and pore volume of the product were determined according to the BET formula principle specified in GB / T7702.20-2008;

[0043] 3) Iodine adsorption value test

[0044] The iodine adsorption value of the sample was tested using the method of GB / T 7702.7-2023;

[0045] Example 1

[0046] 1) adding water to the coal gasification fine slag to control the slurry concentration to 25wt% and stirring under an impeller stirrer to disperse evenly for 30 minutes to obtain fine slag slurry;

[0047] 2) The obtained fine slag slurry is then subjected to gravity separation in a spiral chute, the light component discharge port opening of the spiral chute is controlled to be 20°, the feed rate is 1.5 t / h, and light components, intermediate components and heavy components are obtained, and the light components are collected as a crude product;

[0048] 3) The intermediate components are returned to the spiral chute for a second gravity separation, and the light components are collected; finally, the light components obtained from the two gravity separations are combined, and the recovered carbon residue is obtained through sedimentation filtration and drying (temperature is 110°C, time is 15h).

[0049] 4) Add 3 mol / L dilute hydrochloric acid to the obtained residual carbon, with an acid-residue mass ratio of 8:1, stir for 4 hours at a water bath temperature of 75°C, and a stirring speed of 250 rpm. After the reaction is completed, let it stand, cool and filter, and then rinse with deionized water until the pH is 7. After filtering, dry the filter cake in an oven at 105°C for 12 hours to obtain low-ash and high-adsorption carbon. The test results are:

[0050]

[0051] From the data in the table, we can see that the high adsorption capacity carbon obtained under this condition has a higher specific surface area and iodine value, indicating that its microporous structure is relatively developed. Although it is not as good as high-quality activated carbon, it is suitable for use as a high-efficiency adsorption material.

[0052] Example 2

[0053] 1) adding water to the coal gasification fine slag to control the slurry concentration to 25wt% and stirring under an impeller stirrer to disperse evenly for 30 minutes to obtain fine slag slurry;

[0054] 2) The obtained fine slag slurry is then subjected to gravity separation in a spiral chute, the light component discharge port opening of the spiral chute is controlled to be 20°, the feed rate is 1.5 t / h, and light components, intermediate components and heavy components are obtained, and the light components are collected as a crude product;

[0055] 3) The intermediate components are returned to the spiral chute for the second gravity separation, and the light components are collected. Finally, the light components obtained from the two gravity separations are combined, and the recovered carbon residue is obtained through sedimentation filtration and drying (temperature 110°C, time 15h).

[0056] 4) Add dilute hydrochloric acid with concentrations of 1, 2, 4, and 5 mol / L to the obtained residual carbon, with an acid-slag mass ratio of 8:1, and stir for 4 hours at a water bath temperature of 75°C at a stirring speed of 250rpm. After the reaction is completed, let it stand, cool and filter, and then rinse with deionized water until the pH is 7. After filtering, dry the filter cake in an oven at 105°C for 12 hours to obtain low-ash and high-adsorption carbon. The test results are:

[0057]

[0058] From the data in the table, we can see that when the acid concentration is too low, the ash removal effect is poor. As the acid concentration increases, the ash content of the carbon decreases, but at the same time it also destroys the micropore structure, resulting in an increase in pore volume but a decrease in specific surface area. Therefore, the acid concentration should be moderate.

[0059] Example 3

[0060] 1) adding water to the coal gasification fine slag to control the slurry concentration to 25wt% and stirring under an impeller stirrer to disperse evenly for 30 minutes to obtain fine slag slurry;

[0061] 2) The obtained fine slag slurry is then subjected to gravity separation in a spiral chute. The light component discharge port opening of the spiral chute is controlled to be 15°, 17.5°, 22.5°, and 25° during gravity separation. The feed rate is 1.5 t / h. Light components, intermediate components, and heavy components are obtained, and the light components are collected as a crude product.

[0062] 3) The intermediate components are returned to the spiral chute for the second gravity separation, and the light components are collected. Finally, the light components obtained from the two gravity separations are combined, and the recovered carbon residue is obtained through sedimentation filtration and drying (temperature 110°C, time 15h).

[0063] 4) Add 3 mol / L dilute hydrochloric acid to the obtained residual carbon, with an acid-residue mass ratio of 8:1, and stir for 4 hours at a water bath temperature of 75°C and a stirring speed of 250 rpm. After the reaction is completed, let it stand, cool and filter, and then rinse with deionized water to a pH of 7. After filtration, dry the filter cake in an oven at 105°C for 12 hours to obtain low-ash and high-adsorption carbon.

[0064] The test results are:

[0065]

[0066] From the table data, we can see that with the increase of the light component opening of the spiral chute, the carbon recovery rate increases, but at the same time, the ash content entrained also increases. Therefore, in order to ensure lower ash content and higher recovery rate at the same time, a suitable opening should be selected.

[0067] Example 4

[0068] 1) adding water to the coal gasification fine slag to control the slurry concentration to 15wt%, 20wt%, 30wt%, 35wt%, stirring under an impeller stirrer to disperse evenly for 30 minutes to obtain fine slag slurry;

[0069] 2) The obtained fine slag slurry is then subjected to gravity separation in a spiral chute. During gravity separation, the light component discharge port opening of the spiral chute is controlled to be 20°, and the feed rate is 1.5 t / h to obtain light components, intermediate components and heavy components, and the light components are collected as a crude product;

[0070] 3) The intermediate components are returned to the spiral chute for the second gravity separation, and the light components are collected. Finally, the light components obtained from the two gravity separations are combined, and the recovered carbon residue is obtained through sedimentation filtration and drying (temperature 110°C, time 15h).

[0071] 4) Add 3 mol / L dilute hydrochloric acid to the obtained residual carbon, with an acid-residue mass ratio of 8:1, and stir for 4 hours at a water bath temperature of 60-80°C and a stirring speed of 250 rpm. After the reaction is completed, let it stand, cool and filter, and then rinse with deionized water to a pH of 7. After filtration, dry the filter cake in an oven at 105°C for 12 hours to obtain low-ash and high-adsorption carbon.

[0072] The test results are:

[0073]

[0074] From the table data, we can see that the appropriate slurry concentration also affects the yield and ash content of the product. Although the slurry concentration is low, the yield is high, but the ash content is high. When the slurry concentration is high, the ash content and yield both tend to decrease, so the appropriate slurry concentration should be selected.

[0075] Example 5

[0076] 1) adding water to the coal gasification fine slag to control the slurry concentration to 25wt%, stirring under an impeller stirrer to disperse evenly for 30 minutes to obtain fine slag slurry;

[0077] 2) The obtained fine slag slurry is then subjected to gravity separation in a spiral chute. During gravity separation, the light component discharge port opening of the spiral chute is controlled to be 20°, and the feed rate is 1t / h and 2t / h, respectively, to obtain light components, intermediate components and heavy components, and the light components are collected as a crude product;

[0078] 3) The intermediate components are returned to the spiral chute for the second gravity separation, and the light components are collected. Finally, the light components obtained from the two gravity separations are combined, and the recovered carbon residue is obtained through sedimentation filtration and drying (temperature 110°C, time 15h).

[0079] 4) Add 3 mol / L dilute hydrochloric acid to the obtained residual carbon, with an acid-residue mass ratio of 8:1, and stir for 4 hours at a water bath temperature of 60-80°C and a stirring speed of 250 rpm. After the reaction is completed, let it stand, cool and filter, and then rinse with deionized water to a pH of 7. After filtration, dry the filter cake in an oven at 105°C for 12 hours to obtain low-ash and high-adsorption carbon.

[0080] The test results are:

[0081]

[0082] From the data in the table, we can see that when the feed rate during gravity separation is too small, the ash content of the intermediate product will be lower but the recovery rate will also be low. When the feed rate increases, both the ash content and the yield will tend to increase, so it is also important to choose the appropriate feed rate.

[0083] Example 6

[0084] 1) adding water to the coal gasification fine slag to control the slurry concentration to 25wt% and stirring under an impeller stirrer to disperse evenly for 30 minutes to obtain fine slag slurry;

[0085] 2) The obtained slurry is then subjected to gravity separation in a spiral chute, the light component discharge port opening of the spiral chute is controlled to be 20°, the feed rate is 1.5 t / h, and light components, intermediate components and heavy components are obtained, and the light components are collected as a crude product;

[0086] 3) The intermediate components are returned to the spiral chute for the second gravity separation, and the light components are collected. Finally, the light components obtained from the two gravity separations are combined, and the recovered carbon residue is obtained through sedimentation filtration and drying (temperature 110°C, time 15h).

[0087] 4) Add 3 mol / L dilute sulfuric acid to the obtained residual carbon, with an acid-slag mass ratio of 8:1, stir for 4 hours at a water bath temperature of 60-80°C and a stirring speed of 250 rpm. After the reaction is completed, let it stand, cool and filter, then rinse with deionized water to a pH of 7. After filtering, dry the filter cake in an oven at 105°C for 12 hours to obtain a carbon with high adsorption capacity.

[0088] The test results are:

[0089]

[0090]

[0091] It can be seen from the table data that compared with Example 1, the deashing effect of sulfuric acid is far inferior to that of hydrochloric acid, and the specific surface area and pore volume are also lower. It is speculated that this is because the production of low-solubility sulfate precipitation blocks the pores of the residual carbon, resulting in a decrease in the specific surface area and pore volume.

[0092] Comparative Example 1

[0093] 1) adding water to the coal gasification fine slag to control the slurry concentration to 25wt% and stirring under an impeller stirrer to disperse evenly for 30 minutes to obtain fine slag slurry;

[0094] 2) The obtained fine slag slurry is then subjected to gravity separation in a spiral chute, the light component discharge port opening of the spiral chute is controlled to be 20°, the feed rate is 1.5 t / h, and light components, intermediate components and heavy components are obtained, and the light components are collected as a crude product;

[0095] 3) The intermediate components are returned to the spiral chute for a second gravity separation, and the light components are collected; finally, the light components obtained from the two gravity separations are combined, and the recovered carbon residue is obtained through sedimentation filtration and drying (temperature is 110°C, time is 15h).

[0096] The test results are:

[0097]

[0098] It can be seen from the table data that, compared with Example 1, the deashing effect and other parameters (such as specific surface area, pore volume and iodine value) of the coal gasification fine slag without acid washing are lower, indicating that acid washing can improve the deashing effect, specific surface area and pore volume of the coal gasification fine slag, thereby effectively improving the adsorption performance of the coal gasification fine slag.

[0099] Comparative Example 2

[0100] Add 3 mol / L dilute hydrochloric acid to the coal gasification fine slag with an acid-slag mass ratio of 8:1. Stir for 4 hours at a water bath temperature of 75°C and a stirring speed of 250 rpm. After the reaction is completed, let it stand, cool and filter, then rinse with deionized water to a pH of 7. After filtration, dry the filter cake in an oven at 105°C for 12 hours to obtain carbon.

[0101] The carbon in this example was tested for performance, and the test results were as follows:

[0102]

[0103] It can be seen from the table data that, compared with Example 1 and Comparative Example 1, the deashing effect and other parameters (such as specific surface area, pore volume and iodine value) of the coal gasification fine slag that is directly pickled without gravity separation are lower, and it can be seen from the data that gravity separation and pickling synergistically increase the specific surface area of ​​the coal gasification fine slag, effectively improving its adsorption value.

[0104] Application Comparative Example 1

[0105] In order to compare the adsorption capacity of the product (taking the low-ash and high-adsorption carbon prepared in Example 1 as an example) and industrial activated carbon, coconut shell activated carbon was used for comparative testing. First, the specific surface area, pore volume and iodine value of coconut shell activated carbon were measured, and finally the adsorption performance of the product of the present invention and coconut shell activated carbon on diesel was compared. The test results are as follows:

[0106]

[0107] It can be seen from the table data that the high adsorption capacity carbon of the product of the present invention is much lower than that of industrial coconut shell activated carbon in terms of specific surface area, pore volume and iodine value, but its adsorption capacity for diesel is stronger than that of coconut shell activated carbon. This is because the low-ash and high-adsorption capacity carbon obtained by the method of the present application has a richer mesoporous structure and lipophilic functional groups than coconut shell activated carbon, and the carbon extracted from the coal gasification fine residue has a better adsorption of macromolecular oil substances. In addition, its low price makes it more suitable as an adsorption material for industrial oil-containing solid waste.

[0108] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

Claims

1. A method for recovering low-ash and high-adsorption carbon from coal gasification fine slag, characterized in that: The steps include: 1) Slurrying coal gasification fine slag to obtain fine slag slurry; 2) The fine slag slurry in step 1) is subjected to gravity separation to collect the light component slurry.

2. The method for recovering low-ash and high-adsorption carbon from coal gasification fine slag according to claim 1, characterized in that: The mass concentration of the fine slag slurry is 15-60wt%.

3. The method for recovering low-ash and high-adsorption carbon from coal gasification fine slag according to claim 1, characterized in that: The intermediate components obtained after the gravity separation in step 2) are subjected to multiple gravity separations.

4. The method for recovering low-ash and high-adsorption carbon from coal gasification fine slag according to any one of claims 1 to 3, characterized in that: The method also includes subjecting the light component slurry obtained by gravity separation to sedimentation filtration to obtain filter cake, and then drying and acid washing the filter cake to deash, so as to obtain carbon with low ash and high adsorption capacity.

5. The method for recovering low-ash and high-adsorption carbon from coal gasification fine slag according to claim 4, characterized in that: The drying process parameters are: temperature of 100-120° C. and time of 12-24 hours.

6. The method for recovering low-ash and high-adsorption carbon from coal gasification fine slag according to claim 4, characterized in that: The process conditions of acid washing and deashing are as follows: adding dilute hydrochloric acid to the dried filter cake, stirring and reacting at a speed of 200-300 rpm at a water bath temperature of 60-80°C for 2-4 hours, then cooling and filtering, then rinsing with deionized water until neutral, and drying.

7. The method for recovering low-ash and high-adsorption carbon from coal gasification fine slag according to claim 6, characterized in that: The concentration of the dilute hydrochloric acid is 1-5 mol / L, and the mass ratio of the dilute hydrochloric acid to the filter cake is (1-10):

1.

8. The method for recovering low-ash and high-adsorption carbon from coal gasification fine slag according to claim 6, characterized in that: The drying process conditions are: temperature of 100-120° C. and drying time of 5-20 hours.

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