A method for safe treatment and comprehensive utilization of multi-component coal gasification waste residue

Abstract

A method for the safe treatment and comprehensive utilization of multiple components of coal gasification waste residues. The method first prepares coal gasification fine residues into a slurry, adds a collector and a frother, and stirs to obtain flotation clean carbon and flotation tail ash; adds hydrochloric acid solution to the flotation clean carbon, filters to obtain acid-washed carbon residue and acidic filtrate; adds potassium hydroxide to the carbon residue to activate it to obtain a porous carbon material; mixes the acidic filtrate with the flotation tail ash, adds hydrochloric acid solution, and filters to obtain a silicon-alumina residue and filtrate; adjusts the pH of the filtrate to 8.5-9.5, and filters to obtain a calcium-rich filtrate; introduces CO2 gas into the calcium-rich filtrate to mineralize and carbonate the calcium-rich filtrate; adds sodium hydroxide to the silicon-alumina residue for alkali fusion activation, and then adds trimethylchlorosilane and hexane, and dries to obtain Al2O3-SiO2 aerogel. The method can convert carbon, calcium, aluminum, and silicon in the coal gasification waste residue into porous carbon, calcium-rich filtrate, and Al2O3-SiO2 aerogel, thereby achieving effective utilization of multiple components.

Description

Technical Field

[0001] The present invention belongs to the technical field of solid waste resource utilization, and specifically relates to a method for safe treatment and comprehensive utilization of multi-component coal gasification waste residue. Background Art

[0002] Coal chemical industry represents a new type of productive force. Gasification slag is a typical solid waste generated by the coal chemical process, with large annual output. Large-scale storage not only occupies land but also pollutes the surrounding environment, including soil, air, and water. However, there is currently no effective method for large-scale utilization. Gasification slag contains a large amount of unburned carbon and is well-developed in pores. It is also rich in elements such as silicon, aluminum, and calcium. While there are reports of treating gasification slag as a porous material for wastewater treatment and carbon dioxide capture, there are no reports that fully and comprehensively utilize the porous carbon components and mineral elements in gasification slag. Summary of the Invention

[0003] The purpose of the present invention is to provide a method for the safe treatment and comprehensive utilization of multiple components of coal gasification waste residue. This method can achieve the effective utilization of the carbon, calcium, aluminum, and silicon components in the coal gasification waste residue. The prepared porous carbon and calcium-rich filtrate can be used for carbon dioxide capture, and the Al2O3-SiO2 aerogel can be used as an adsorption material for sewage treatment or a building insulation material.

[0004] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a method for safe treatment and comprehensive utilization of multi-component coal gasification waste residue, comprising the following steps:

[0005] (1) The coal gasification fine slag is prepared into a slurry, and a certain amount of collector and frother are added and stirred to obtain flotation fine carbon and flotation tailings;

[0006] (2) adding hydrochloric acid solution to the flotation refined carbon to leach the metal elements, filtering to obtain the acid-washed residual carbon, and washing it with deionized water until it is neutral, and obtaining an acidic filtrate;

[0007] (3) adding potassium hydroxide to the residual carbon obtained in step (2) to activate it to obtain a porous carbon material for CO2 capture;

[0008] (4) mixing the acidic filtrate obtained in step (2) with the flotation tailings obtained in step (1), adding hydrochloric acid solution, and filtering to obtain silicon-aluminum residue and filtrate;

[0009] (5) adding ammonia water to the filtrate obtained in step (4) to adjust the pH to 8.5-9.5, filtering out particulate matter in the filtrate to obtain a calcium-rich filtrate for CO2 capture;

[0010] (6) introducing CO2 gas into the calcium-rich filtrate obtained in step (5) to mineralize and carbonate the calcium-rich filtrate;

[0011] (7) Sodium hydroxide is added to the silicon-aluminum residue obtained in step (4) for alkali melting activation, and then trimethylchlorosilane and hexane are added, and then dried to obtain Al2O3-SiO2 aerogel.

[0012] Preferably, in step (1), the collector is diesel or methyl oleate, and the foaming agent is octanol; the concentration of the slurry is 100 g / L; the amounts of the collector and foaming agent are 7 kg / t coal gasification fine slag and 10 kg / t coal gasification fine slag, respectively.

[0013] Preferably, in step (1), the specific surface area of ​​the coal gasification fine slag is 200m 2 / g; the ash composition of the coal gasification fine slag contains the following components: by weight percentage, 2.13% K2O, 1.98% Na2O, 50.94% SiO2, 18.92% Al2O3, 9.14% CaO, 9.96% Fe2O3, 3.57% MgO, and the rest are residual carbon and other impurities; the loss on ignition of the coal gasification fine slag is 23.06%.

[0014] Preferably, in step (2), the concentration of the hydrochloric acid solution is 1.5-3 mol / L, the liquid-to-solid ratio of the flotation refined carbon to the hydrochloric acid solution is 15-30 mL / g, the leaching time is 30-60 min, and the leaching temperature is 60-90°C.

[0015] Preferably, in step (3), the mass ratio of residual carbon to potassium hydroxide is 1:(1-3); the activation temperature is 700-850° C., and the activation time is 60-120 min.

[0016] Preferably, in step (4), the concentration of the hydrochloric acid solution is 1.5-3 mol / L, the liquid-to-solid ratio is 15-30 mL / g, the leaching time is 30-60 min, and the leaching temperature is 60-90°C.

[0017] Preferably, in step (6), the mineralization reaction temperature is 30-60° C., and the reaction time is 30-60 min.

[0018] Preferably, in step (7), the activation temperature is 750-850° C., and the reaction time is 60-90 min.

[0019] Preferably, in step (7), the mass ratio between trimethylchlorosilane and hexane is (0.22-0.28):1.

[0020] Preferably, in step (7), drying is first performed at room temperature for 12-15 hours, and then dried at 75-85°C for 6-8 hours.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention can fully and comprehensively utilize the porous carbon components and mineral elements in coal-based solid waste, obtaining flotation refined carbon and tailing ash through a foam flotation method. The flotation refined carbon is further activated by KOH to prepare a porous carbon material while recovering the mineral elements leached during the pickling process. The resulting acidic waste liquid is further mixed with the tailing ash to extract the mineral elements and obtain a calcium-rich filtrate. The remaining silicon-aluminum residue is activated by alkali to obtain a silicon-aluminum solution, which is then aged to obtain Al2O3-SiO2 aerogel. At this point, the three materials of porous carbon, calcium-rich filtrate, and Al2O3-SiO2 aerogel are successfully prepared. The prepared porous carbon and calcium-rich filtrate can be used for carbon dioxide capture, and the Al2O3-SiO2 aerogel can be used as an adsorbent material for sewage treatment or as a building insulation material, thus realizing a method for the safe disposal and comprehensive utilization of the carbon, calcium, aluminum, and silicon multi-components of coal gasification waste. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0024] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0025] All raw materials and reagents in the examples of this application were purchased on the market or prepared according to conventional methods well known to those skilled in the art.

[0026] The specific surface area of ​​the coal gasification slag used in the following examples is 200m 2 / g; the ash composition of the coal gasification fine slag contains the following components: by weight percentage, 2.13% K2O, 1.98% Na2O, 50.94% SiO2, 18.92% Al2O3, 9.14% CaO, 9.96% Fe2O3, 3.57% MgO, and the rest are residual carbon and other impurities; the loss on ignition of the coal gasification fine slag is 23.06%.

[0027] Example 1

[0028] like Figure 1 As shown, a method for safe treatment and comprehensive utilization of multi-component coal gasification waste residue includes the following steps:

[0029] (1) The coal gasification fine slag was prepared into a slurry with a concentration of 100 g / L, and a certain amount of collector and foaming agent was added and stirred. Based on the calculation of treating 1 ton of coal gasification fine slag, the amount of collector diesel was 7 kg, and the amount of foaming agent octanol was 10 kg. The flotation fine carbon yield was 37.62%, the loss on ignition was 59.78%, the flotation tail ash yield was 62.38%, and the loss on ignition was 4.78%.

[0030] (2) Add 2 mol / L hydrochloric acid solution to the flotation refined carbon to leach metal elements. The liquid-solid ratio of the flotation refined carbon to the hydrochloric acid solution is 25 mL / g, the leaching time is 50 min, the leaching temperature is 80 ° C, the calcium ion leaching rate is 99%, and the specific surface area of ​​the flotation residual carbon after pickling is 496 m 2 / g, filter to obtain the acid-washed carbon residue and rinse with deionized water until neutral, and obtain an acidic filtrate;

[0031] (3) Potassium hydroxide is added to the residual carbon obtained in step (2) to activate the porous carbon material for CO2 capture; the mass ratio between the residual carbon and potassium hydroxide is 1:2; the activation temperature is 800°C, the activation time is 90 min; the specific surface area of ​​the prepared porous carbon material is 1480 m 2 / g, the CO2 adsorption capacity reached 4.7mmol / g at 0℃, and the CO2 adsorption saturation time was 2min;

[0032] (4) mixing the acidic filtrate obtained in step (2) with the flotation tailings obtained in step (1), adding a hydrochloric acid solution with a concentration of 2 mol / L, a liquid-to-solid ratio of 25 mL / g, a leaching time of 50 min, a leaching temperature of 80° C., and filtering to obtain a silicon-aluminum residue and a filtrate; the calcium ion leaching rate is 99%;

[0033] (5) adding ammonia water to the filtrate obtained in step (4) to adjust the pH to 8.5-9.5, filtering out particulate matter in the filtrate to obtain a calcium-rich filtrate for CO2 capture;

[0034] (6) introducing CO2 gas into the calcium-rich filtrate obtained in step (5) for mineralization, with the mineralization reaction temperature being 50°C and the reaction time being 50 min, so that the calcium-rich filtrate is carbonated, and the carbonation efficiency is 97%;

[0035] (7) Sodium hydroxide was added to the silicon-aluminum residue obtained in step (4) for alkali melting activation, the activation temperature was 800°C, the reaction time was 75 min, and then trimethylchlorosilane and hexane were added, the mass ratio between trimethylchlorosilane and hexane was 0.26:1, and then dried at room temperature for 15 h, and then dried at 80°C for 7.5 h to obtain Al2O3-SiO2 aerogel, the specific surface area of ​​the aerogel reached 650 m 2 / g.

[0036] Example 2

[0037] like Figure 1 As shown, a method for safe treatment and comprehensive utilization of multi-component coal gasification waste residue includes the following steps:

[0038] (1) Coal gasification fine slag was prepared into a slurry with a concentration of 100 g / L, and a certain amount of collector and foaming agent was added and stirred. Based on the calculation of treating 1 ton of coal gasification fine slag, the amount of collector methyl oleate was 7 kg, and the amount of foaming agent octanol was 10 kg; the flotation fine carbon yield was 37.62%, the loss on ignition was 59.78%, the flotation tail ash yield was 62.38%, and the loss on ignition was 4.78%;

[0039] (2) Add 3 mol / L hydrochloric acid solution to the flotation refined carbon to leach metal elements. The liquid-solid ratio of the flotation refined carbon to the hydrochloric acid solution is 30 mL / g, the leaching time is 60 min, the leaching temperature is 90 ° C, the calcium ion leaching rate is 99.5%, and the specific surface area of ​​the flotation residual carbon after pickling is 508 m 2 / g, filter to obtain the acid-washed carbon residue and rinse with deionized water until neutral, and obtain an acidic filtrate;

[0040] (3) Potassium hydroxide was added to the residual carbon obtained in step (2) to activate the porous carbon material for CO2 capture; the mass ratio between the residual carbon and potassium hydroxide was 1:3; the activation temperature was 850°C, the activation time was 120 min; the specific surface area of ​​the prepared porous carbon material was 1210 m 2 / g, the CO2 adsorption capacity reaches 4.4mmol / g at 0℃, and the CO2 adsorption saturation time is 2min;

[0041] (4) mixing the acidic filtrate obtained in step (2) with the flotation tailings obtained in step (1), adding a hydrochloric acid solution having a concentration of 3 mol / L, a liquid-to-solid ratio of 30 mL / g, a leaching time of 60 min, a leaching temperature of 90° C., and filtering to obtain a silicon-aluminum residue and a filtrate; the calcium ion leaching rate is 99.5%;

[0042] (5) adding ammonia water to the filtrate obtained in step (4) to adjust the pH to 8.5-9.5, filtering out particulate matter in the filtrate to obtain a calcium-rich filtrate for CO2 capture;

[0043] (6) introducing CO2 gas into the calcium-rich filtrate obtained in step (5) for mineralization, with the mineralization reaction temperature at 60°C and the reaction time at 60 min, to carbonate the calcium-rich filtrate, with a carbonation efficiency of 98%;

[0044] (7) Sodium hydroxide was added to the silicon-aluminum residue obtained in step (4) for alkali melting activation, the activation temperature was 850°C, the reaction time was 90 min, and then trimethylchlorosilane and hexane were added, the mass ratio between trimethylchlorosilane and hexane was 0.28:1, and then dried at room temperature for 15 h, and then dried at 85°C for 7.5 h to obtain Al2O3-SiO2 aerogel, the specific surface area of ​​the aerogel reached 710 m 2 / g.

[0045] Example 3

[0046] like Figure 1 As shown, a method for safe treatment and comprehensive utilization of multi-component coal gasification waste residue includes the following steps:

[0047] (1) The coal gasification fine slag was prepared into a slurry with a concentration of 100 g / L, and a certain amount of collector and foaming agent was added and stirred. Based on the calculation of treating 1 ton of coal gasification fine slag, the amount of collector diesel was 7 kg, and the amount of foaming agent octanol was 10 kg. The flotation fine carbon yield was 37.62%, the loss on ignition was 59.78%, the flotation tail ash yield was 62.38%, and the loss on ignition was 4.78%.

[0048] (2) Add 1.5 mol / L hydrochloric acid solution to the flotation clean carbon to leach metal elements. The liquid-solid ratio of the flotation clean carbon to the hydrochloric acid solution is 20 mL / g, the leaching time is 30 min, the leaching temperature is 60 ° C, the calcium ion leaching rate is 92%, and the specific surface area of ​​the flotation residual carbon after pickling is 463 m 2 / g, filter to obtain the acid-washed carbon residue and rinse with deionized water until neutral, and obtain an acidic filtrate;

[0049] (3) Potassium hydroxide is added to the residual carbon obtained in step (2) to activate the porous carbon material for CO2 capture; the mass ratio between the residual carbon and potassium hydroxide is 1:1; the activation temperature is 750°C, and the activation time is 60 min; the specific surface area of ​​the prepared porous carbon material is 1015 m 2 / g, the CO2 adsorption capacity reaches 3.7mmol / g at 0℃, and the CO2 adsorption saturation time is 2min;

[0050] (4) the acidic filtrate obtained in step (2) was mixed with the flotation tailings obtained in step (1), and then a hydrochloric acid solution with a concentration of 1.5 mol / L was added, the liquid-to-solid ratio was 20 mL / g, the leaching time was 30 min, the leaching temperature was 60° C., and the silicon-aluminum residue and the filtrate were filtered to obtain the calcium ion leaching rate of 94%;

[0051] (5) adding ammonia water to the filtrate obtained in step (4) to adjust the pH to 8.5-9.5, filtering out particulate matter in the filtrate to obtain a calcium-rich filtrate for CO2 capture;

[0052] (6) introducing CO2 gas into the calcium-rich filtrate obtained in step (5) for mineralization, with the mineralization reaction temperature at 45°C and the reaction time at 30 min, to carbonate the calcium-rich filtrate, with a carbonation efficiency of 91%;

[0053] (7) Sodium hydroxide was added to the silicon-aluminum residue obtained in step (4) for alkali melting activation, the activation temperature was 750°C, the reaction time was 60 min, and then trimethylchlorosilane and hexane were added, the mass ratio between trimethylchlorosilane and hexane was 0.22:1, and then dried at room temperature for 12 h, and then dried at 75°C for 7.5 h to obtain Al2O3-SiO2 aerogel, the specific surface area of ​​the aerogel reached 595 m 2 / g.

Claims

1. A method for safe treatment and comprehensive utilization of multi-component coal gasification waste residue, characterized in that: The following steps are involved: (1) The coal gasification fine slag is prepared into a slurry, and a certain amount of collector and frother are added and stirred to obtain flotation fine carbon and flotation tailings; (2) adding hydrochloric acid solution to the flotation refined carbon to leach the metal elements, filtering to obtain the acid-washed residual carbon, and washing it with deionized water until it is neutral, and obtaining an acidic filtrate; (3) adding potassium hydroxide to the residual carbon obtained in step (2) to activate it to obtain a porous carbon material for CO2 capture; (4) mixing the acidic filtrate obtained in step (2) with the flotation tailings obtained in step (1), adding hydrochloric acid solution, and filtering to obtain silicon-aluminum residue and filtrate; (5) adding ammonia water to the filtrate obtained in step (4) to adjust the pH to 8.5-9.5, filtering out particulate matter in the filtrate to obtain a calcium-rich filtrate for CO2 capture; (6) introducing CO2 gas into the calcium-rich filtrate obtained in step (5) to mineralize and carbonate the calcium-rich filtrate; (7) Sodium hydroxide is added to the silicon-aluminum residue obtained in step (4) for alkali melting activation, and then trimethylchlorosilane and hexane are added, and then dried to obtain Al2O3-SiO2 aerogel.

2. The method for safe treatment and comprehensive utilization of multi-component coal gasification waste residue according to claim 1, characterized in that: In step (1), the collector is diesel or methyl oleate, and the foaming agent is octanol; the concentration of the slurry is 100 g / L; the amounts of the collector and foaming agent are 7 kg / t coal gasification fine slag and 10 kg / t coal gasification fine slag, respectively.

3. A method for safe treatment and comprehensive utilization of multi-component coal gasification waste residue according to claim 1 or 2, characterized in that: In step (1), the specific surface area of ​​the coal gasification fine slag is 200m 2 / g; the ash composition of the coal gasification fine slag contains the following components: by weight percentage, 2.13% K2O, 1.98% Na2O, 50.94% SiO2, 18.92% Al2O3, 9.14% CaO, 9.96% Fe2O3, 3.57% MgO, and the rest are residual carbon and other impurities; the loss on ignition of the coal gasification fine slag is 23.06%.

4. A method for safe treatment and comprehensive utilization of multi-component coal gasification waste residue according to claim 1 or 2, characterized in that: In step (2), the concentration of the hydrochloric acid solution is 1.5-3 mol / L, the liquid-solid ratio of the flotation refined carbon to the hydrochloric acid solution is 15-30 mL / g, the leaching time is 30-60 min, and the leaching temperature is 60-90°C.

5. A method for safe treatment and comprehensive utilization of multi-component coal gasification waste residue according to claim 1 or 2, characterized in that: In step (3), the mass ratio of residual carbon to potassium hydroxide is 1:(1-3); the activation temperature is 700-850° C., and the activation time is 60-120 min.

6. A method for safe treatment and comprehensive utilization of multi-component coal gasification waste residue according to claim 1 or 2, characterized in that: In step (4), the concentration of the hydrochloric acid solution is 1.5-3 mol / L, the liquid-to-solid ratio is 15-30 mL / g, the leaching time is 30-60 min, and the leaching temperature is 60-90° C.

7. A method for safe treatment and comprehensive utilization of multi-component coal gasification waste residue according to claim 1 or 2, characterized in that: In step (6), the mineralization reaction temperature is 30-60° C., and the reaction time is 30-60 min.

8. A method for safe treatment and comprehensive utilization of multi-component coal gasification waste residue according to claim 1 or 2, characterized in that: In step (7), the activation temperature is 750-850° C., and the reaction time is 60-90 min.

9. A method for safe treatment and comprehensive utilization of multi-component coal gasification waste residue according to claim 1 or 2, characterized in that: In step (7), the mass ratio between trimethylchlorosilane and hexane is (0.22-0.28):

1.

10. A method for safe treatment and comprehensive utilization of multi-component coal gasification waste residue according to claim 1 or 2, characterized in that: In step (7), the product is first dried at room temperature for 12-15 h, and then dried at 75-85° C. for 6-8 h.

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