Coal-based solid waste selection-metallurgy-material resource comprehensive utilization process method and application thereof

Abstract

The application provides a coal-based solid waste flotation-metallurgy-material resource comprehensive utilization process method and application, and belongs to the technical field of coal-based solid waste comprehensive utilization.The coal-based solid waste is first separated by flotation to obtain residual carbon and tail ash; then the tail ash is dried and alkali melted to become active material; then the active material is leached and filtered to obtain leaching liquid and leaching residue, and Li and Ga in the leaching liquid are adsorbed and enriched; the adsorbed leaching liquid is adjusted in silicon-aluminum ratio, hydrothermally crystallized, filtered and high-temperature calcined to obtain mesoporous molecular sieve; the filtered silicon-containing alkali liquor is carbonized and calcined to obtain white carbon black; the tail ash and the leaching residue are mixed, and through moisture adjustment and curing process, a geopolymer product is obtained.The method in the application does not produce waste residue and waste water in the implementation process, finally obtains four products of Li and Ga enrichment product, geopolymer product, mesoporous molecular sieve and white carbon black, realizes full and comprehensive utilization of the coal-based solid waste, and has good environmental benefits and great significance.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of comprehensive utilization of coal-based solid waste, and particularly relates to a coal-based solid waste selection-metallurgy-material resource comprehensive utilization process method and application thereof. BACKGROUND

[0002] With the rapid development of modern coal chemical industry, coal gasification as the leading technology of modern coal chemical industry, the amount of coal gasification slag produced in the gasification process increases sharply. However, due to the limitations of technology and cost, at present, landfill and stockpiling are mainly used, which not only occupies a large amount of land resources, but also faces the risk of pollution of water bodies and soil by harmful heavy metals in coal gasification slag, seriously threatening the ecological environment. At the same time, this disposal method of coal gasification slag is also a waste of resources.

[0003] At present, the resource utilization of coal gasification slag in the modern coal chemical industry in China is still in its infancy, and there is no method for full-component resource utilization of coal gasification slag. SUMMARY

[0004] In order to solve the above technical problems, the present application provides a coal-based solid waste selection-metallurgy-material resource comprehensive utilization process method and application thereof. In the present application, the coal-based solid waste is first floated and separated to obtain residual carbon and tail ash; then the tail ash is dried and alkali-fused into active material; then the active material is leached and filtered to obtain leaching solution and leaching residue, and Li and Ga in the leaching solution are adsorbed and enriched; the adsorbed leaching solution is adjusted in silicon-aluminum ratio, hydrothermally crystallized, filtered and high-temperature calcined to obtain mesoporous molecular sieve; the filtered silicon-containing alkali liquor is carbonized and calcined to obtain white carbon black; the tail ash and the leaching residue are mixed and adjusted in water content, and a geopolymer product is obtained through the curing process. The method in the present application does not produce waste slag and waste water in the implementation process, and finally four products, i.e. Li and Ga enrichment product, geopolymer product, mesoporous molecular sieve and white carbon black, are obtained, realizing the full and comprehensive utilization of coal-based solid waste, and the environmental benefits are also good, which is of great significance.

[0005] In order to achieve the above purpose, the present application adopts the following technical solution:

[0006] The present application provides a coal-based solid waste selection-metallurgy-material resource comprehensive utilization process method, wherein the coal-based solid waste is fly ash and / or coal gasification slag, and the method specifically comprises the following steps:

[0007] (1) floating and separating the coal-based solid waste to obtain residual carbon and tail ash;

[0008] (2) drying and alkali-fusing the tail ash into active material;

[0009] (3) leaching and filtering the active material to obtain leaching solution and leaching residue, and Li and Ga in the leaching solution are enriched by adsorbent to obtain Li and Ga enrichment product;

[0010] (4) The adsorbed leaching solution is adjusted in silicon-aluminum ratio, hydrothermally crystallized, filtered, and high-temperature calcined to obtain a mesoporous molecular sieve;

[0011] (5) The silicon-containing alkali solution filtered in step (4) is carbonated and calcined to obtain white carbon black.

[0012] (6) The tail ash obtained by flotation separation in step (1) is mixed with the leaching residue filtered in step (3), and a geopolymer product is obtained by water adjustment and curing.

[0013] Preferably, in step (1), the coal-based solid waste flotation separation further comprises a grinding step, specifically: grinding for 5-30 min at a grinding concentration of 30%-50% to fully separate the carbon-ash.

[0014] Preferably, in step (2), the alkali fusion conditions are as follows: sodium hydroxide is used as the alkali flux, the tail ash is mixed with the alkali flux at a mass ratio of 1:(1-1.5) and then ground, and then calcined at an alkali fusion temperature of 400-600°C for 1-4 h, wherein the temperature rising rate is 5-10°C / min.

[0015] Preferably, in step (3), the leaching conditions are as follows: deionized water is used as the leaching agent, the liquid-solid ratio of the deionized water to the alkali-fused tail ash is (4-15):1 L / kg, and the leaching operation is performed with stirring at 200-600 rpm / min for 1-4 h.

[0016] Preferably, in step (3), the Li and Ga in the leaching solution are enriched by a manganese-based lithium ion sieve and a gallium extraction resin, respectively.

[0017] Preferably, in step (4), the silicon source and the aluminum source for adjusting the silicon-aluminum ratio of the leaching solution are sodium silicate and sodium metaaluminate, respectively; and the preparation conditions of the mesoporous molecular sieve are as follows: silicon-aluminum ratio 2-3, hydrothermal temperature 80-200°C, hydrothermal time 6-24 h, calcination temperature 500-600°C, and calcination time 3-5 h.

[0018] Preferably, in step (5), the carbonation process is divided into two steps: one-step carbonation for impurity removal and two-step carbonation for precipitation, and the white carbon black is obtained after drying the precipitate.

[0019] Preferably, in step (5), the one-step carbonation for impurity removal ends when the pH of the solution decreases to 9.5-10.5, and the two-step carbonation for precipitation ends when the pH of the solution decreases to 7.5-8.5.

[0020] Preferably, in step (6), the mixing mass ratio of the tail ash to the leaching residue is 1:(0.5-1.5), the liquid-solid ratio of the added water is 0.2-0.4, the slurry is formed by stirring, and the curing temperature is 30-90°C.

[0021] The application also provides application of the coal-based solid waste selection-metallurgy-material resource comprehensive utilization process in Li and Ga enriched product and / or geopolymer product and / or mesoporous molecular sieve and / or white carbon black preparation.

[0022] Compared with the prior art, the application has the following technical effects:

[0023] (1) The application takes coal-based solid waste as raw material, processes the coal-based solid waste through a flotation separation method, and utilizes the obtained residual carbon and flotation tail ash respectively, so that comprehensive utilization of the coal-based solid waste is fully realized.

[0024] (2) The application processes the flotation tail ash through an alkali roasting method, then obtains a Li and Ga containing leaching solution through leaching, and realizes Li and Ga enrichment through an adsorption method, so that recycling of Li and Ga is realized.

[0025] (3) The application mixes the leaching residue and the flotation tail ash of the coal-based solid waste together as raw material for synthesizing geopolymer, uses the residual alkali in the leaching residue as an activator and additional water to adjust and stir to form a slurry, and forms a geopolymer with good stability and high strength through shaping and curing of the slurry, which is used for building materials.

[0026] (4) After Li and Ga enrichment and separation of the leaching solution, sodium silicate and sodium metaaluminate are added to the remaining strong alkaline solution to adjust the silicon-aluminum ratio and a template agent, and mesoporous molecular sieve is obtained through hydrothermal crystallization, filtration and high temperature calcination.

[0027] (5) The silicon containing alkali solution separated in the process of synthesizing the molecular sieve is subjected to a two-step carbon separation process by introducing carbon dioxide into the solution to obtain a precipitate, and white carbon black is obtained after drying the precipitate, so that recycling of the leaching solution is fully realized.

[0028] (6) The resource utilization method provided by the application does not produce waste residue and waste water in the implementation process, and four products, i.e., Li and Ga enriched product, geopolymer, mesoporous molecular sieve and white carbon black, are finally obtained through the whole process, so that the environmental benefits are good. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 The figure is a process flow diagram in the embodiment 1 of the application. DETAILED DESCRIPTION

[0030] The following examples are used to illustrate the application, but are not used to limit the scope of the application. Modifications or replacements of the method, steps, conditions, instruments or reagents of the application without departing from the spirit and essence of the application all belong to the scope of the application.

[0031] The technical solutions of the present application are further described in detail below in combination with examples.

[0032] Example 1

[0033] A coal gasification slag in Ningxia is used as a raw material for comprehensive utilization, and the composition of the coal gasification slag is SiO2: 50.94%, Al2O3: 19.31%, Fe2O3: 9.87%, CaO: 8.21%, MgO: 4.32%, and the loss on ignition is 24.76%. The process flow shown in the figure is used for comprehensive utilization. Figure 1

[0034] The operation is as follows:

[0035] Step 1. After the coal gasification slag is dried, the coal gasification slag is ground in a rod mill for 10 minutes at a grinding concentration of 50% to fully separate the carbon-ash, and then residual carbon and ash are obtained by flotation. The yield of the flotation residual carbon is 48.27%, the loss on ignition is 47.76%, the yield of the flotation tail ash is 51.73%, and the loss on ignition is 3.3%.

[0036] Step 2. After the tail ash obtained by flotation is dried to a constant weight, the tail ash is then mixed with sodium hydroxide at a mass ratio of 1:1.2 and ground to be uniform. The ground material is calcined in a muffle furnace at 500°C for 2 hours at a heating rate of 10°C / min. After reaching the preset program, the material is cooled to room temperature and ground.

[0037] Step 3. The calcined and ground sample is mixed with deionized water at a ratio of 1:5 kg / L and stirred in a stirring barrel at room temperature. The stirring time is 2 hours and the stirring speed is 400 rpm / min. After stirring, filtration is performed to obtain an alkaline residue and a Li and Ga-containing leaching solution. Then, Li and Ga are adsorbed from the leaching solution by using a manganese-based lithium ion sieve and a gallium extraction resin.

[0038] Step 4. A template agent is added to the strong alkali solution after adsorbing Li and Ga, and sodium silicate and sodium metaaluminate are added to adjust the silicon-aluminum ratio to 2. The hydrothermal temperature is 180°C, and the hydrothermal crystallization is carried out for 24 hours. After hydrothermal crystallization, filtration is performed to obtain a solid material and a silicon-containing alkali solution. The solid material is calcined in a muffle furnace at 550°C for 3 hours to remove the template agent. The calcined material is a mesoporous molecular sieve.

[0039] Step 5. Carbon dioxide is introduced into the silicon-containing alkali solution in step 4 in two stages. When the pH of the solution decreases from 13.27 to 10.03, the first-stage carbon separation is completed, and filtration is performed. Then, carbon dioxide is introduced into the filtrate to perform the second-stage carbon separation. When the pH of the solution decreases to 8.02, the second-stage carbon separation is completed, and the precipitate is dried to obtain white carbon black.

[0040] ​Step 6. The flotation tailings in step 1 and the basic residue in step 3 are mixed uniformly at a mass ratio of 1:1.5, then water is added at a liquid-solid ratio of 0.3 for stirring, and then the slurry formed after stirring is transferred to a mold of 40x40x40mm. The coagulation is completed within 15 hours. After curing at room temperature for 28 days, the compressive strength is measured, and the maximum compressive strength is 25.8Mpa.

[0041] Comparative Example 1

[0042] The present comparative example is the comprehensive utilization method of coal gasification fine slag disclosed in CN201710154415.8.

[0043] Comparative analysis of Example 1 and Comparative Example 1 shows that in Comparative Example 1, the carbon-rich component and the silicon-rich component after separation are utilized, the carbon-rich component is used to prepare adsorbent material, and the silicon-rich component is only used to synthesize zeolite, and the waste acid and waste alkali generated in the utilization process are not treated. In the method of Example 1 of the present application, not only the carbon-rich component (residual carbon) and the silicon-rich component (tailings) after separation are utilized, but also the tailings obtained by flotation are first subjected to alkali fusion activation treatment, then Li and Ga key metal elements are extracted therefrom, and the alkali leaching residue after leaching is also used as a raw material for synthesizing geopolymer, and the strong alkali solution after adsorbing Li and Ga is also fully utilized.

[0044] In summary, using the method of the present application, no waste residue and waste water are generated during the implementation process, and finally Li, Ga products, geopolymer, mesoporous molecular sieve and white carbon black are obtained, realizing the full and comprehensive utilization of coal-based solid waste, and the environmental benefits are also good.

[0045] The above-described examples only describe the preferred modes of the present application, and do not limit the scope of the present application. Without departing from the design spirit of the present application, various modifications and improvements to the technical solutions of the present application made by those skilled in the art shall fall within the protection scope determined by the claims of the present application.

Claims

1. A coal-based solid waste selection-metallurgy-material resource comprehensive utilization process method, characterized in that, The coal-based solid waste is fly ash and / or coal gasification slag, and the method specifically comprises the following steps: (1) The coal-based solid waste is floated and separated to obtain residual carbon and tail ash; before the coal-based solid waste is floated and separated, a grinding step is further included, specifically: grinding for 5-30 min at a grinding concentration of 30%-50% to fully separate the carbon-ash; (2) The tail ash is dried and alkali-fused to become an active material; the alkali-fusion conditions are as follows: sodium hydroxide is used as an alkali flux, the tail ash and the alkali flux are mixed and ground at a mass ratio of 1:(1-1.5), and then calcined at an alkali-fusion temperature of 400-600 ℃ for 1-4 h, wherein the temperature rising rate is 5-10 ℃ / min; (3) The active material is leached and filtered to obtain a leaching solution and a leaching residue, and Li and Ga in the leaching solution are enriched by an adsorbent to obtain Li and Ga enrichment products; the leaching conditions are as follows: deionized water is used as a leaching agent, the liquid-solid ratio of the deionized water to the alkali-fused tail ash is (4-15):1 L / kg, and stirring is performed at 200-600 rpm for 1-4 h during the leaching operation; (4) The leaching solution after adsorption is adjusted in silicon-aluminum ratio, hydrothermally crystallized, filtered, and high-temperature calcined to obtain a mesoporous molecular sieve; the silicon source and the aluminum source for adjusting the silicon-aluminum ratio of the leaching solution are sodium silicate and sodium metaaluminate respectively; the preparation conditions of the mesoporous molecular sieve are as follows: the silicon-aluminum ratio is 2-3, the hydrothermal temperature is 80-200 ℃, the hydrothermal time is 6-24 h, the calcination temperature is 500-600 ℃, and the calcination time is 3-5 h; (5) The silicon-containing alkali liquor after filtration in step (4) is carbonized and calcined to obtain white carbon black; the carbonization process is divided into two steps: one-step carbonization for impurity removal and two-step carbonization for precipitation; the white carbon black is obtained after drying the precipitation; wherein the one-step carbonization for impurity removal is completed when the pH of the solution is reduced to 9.5-10.5; the two-step carbonization for precipitation is completed when the pH of the solution is reduced to 7.5-8.5; (6) The tail ash obtained by flotation separation in step (1) is mixed with the leaching residue obtained by filtration in step (3), and a geopolymer product is obtained through water content adjustment and curing; the mass ratio of the tail ash to the leaching residue is 1:(0.5-1.5), the liquid-solid ratio of the added water is 0.2-0.4, the slurry is formed by stirring, and the curing temperature is 30-90 ℃.

2. The coal-based solid waste selection-metallurgical-material resource comprehensive utilization process method according to claim 1, characterized in that, In step (3), Li and Ga in the leaching solution are enriched by a manganese-based lithium ion sieve and a gallium extraction resin respectively.

3. Application of the coal-based solid waste selective-metallurgical-material resource comprehensive utilization process method according to any one of claims 1-2 in the preparation of Li and Ga enrichment products and / or a geopolymer product and / or a mesoporous molecular sieve and / or white carbon black.

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