Application of hydrotalcite as vanadium capturing agent in solid waste stone coal desilicication and vanadium extraction and solid waste stone coal desilicication and vanadium extraction method based on hydrotalcite structure memory effect

Abstract

The invention discloses application of hydrotalcite as a vanadium capturing agent in solid waste stone coal desilicication and vanadium extraction and a solid waste stone coal desilicication and vanadium extraction method based on a hydrotalcite structure memory effect, and relates to the technical field of solid waste resource utilization. The structural memory effect of hydrotalcite is utilized, the hydrotalcite is applied to desiliconization and vanadium extraction of the solid waste stone coal, and the method comprises the following steps: mixing and roasting the stone coal and a vanadium capturing agent to obtain roasted stone coal, mixing the roasted stone coal with inorganic alkali in a solvent, and reacting at 80-95 DEG C to obtain desiliconized stone coal. According to the method, the vanadium content of the desiliconized stone coal can be remarkably improved, so that the requirement of the stone coal vanadium extraction process on the content of raw material vanadium is met, the vanadium extraction efficiency of the stone coal can be remarkably improved, and the resource utilization of the solid waste stone coal is realized. Meanwhile, the method is simple in process and low in cost, and has a good application prospect.

Description

Technical Field

[0001] This invention relates to the field of solid waste resource utilization technology, and in particular to the application of hydrotalcite as a vanadium-capturing agent in the desilication and vanadium extraction of solid waste coal, and a method for desilication and vanadium extraction of solid waste coal based on the structural memory effect of hydrotalcite. Background Technology

[0002] Stone-like coal is a low-carbon, low-calorific-value, low-grade solid waste anthracite, and also a low-grade polymetallic symbiotic ore, with silicon dioxide as its main component. As an important vanadium resource, stone-like coal is the core raw material for vanadium extraction technology, which is widely used in the steel, chemical, and energy storage battery industries, and can extract the key element vanadium from vanadium-bearing stone-like coal.

[0003] In recent years, with the rapid development of the new energy industry, the market demand for vanadium has continued to grow, highlighting the technological value and industrial importance of vanadium extraction from coal shale. Currently, acid leaching is a common process for vanadium extraction from coal shale, which involves leaching vanadium-containing coal shale with acid to dissolve vanadium, followed by separation steps to obtain the finished vanadium product. However, to improve the efficiency of acid leaching for vanadium extraction, the coal shale raw material usually needs to be pretreated to remove silica (i.e., desilication treatment), thereby increasing the vanadium content (grade) of the coal shale raw material. Alkali extraction is currently the mainstream desilication method.

[0004] The conventional alkaline extraction desilication process involves first roasting the coal shale at high temperature to activate the silica in the coal, and then treating the roasted coal with an alkaline solution to remove silica species. However, existing alkaline extraction desilication methods suffer from two major problems that severely restrict subsequent vanadium extraction: First, the desilication efficiency is limited. During the high-temperature roasting and activation process, silica species in the coal shale undergo surface dehydroxylation reactions, and the residual carbon in the coal shale enhances the hydrophobicity of the roasted coal surface, making it difficult for the roasted coal to fully contact and react with the subsequent alkaline solution, directly affecting the desilication efficiency. Second, vanadium is lost. Vanadium oxides in coal shale are acidic oxides, and they inevitably react with the alkali during alkaline extraction, resulting in the loss of vanadium in the form of V₂O₅.

[0005] The aforementioned problems make it difficult for existing alkaline extraction desilication methods to obtain desilicationized coal with high vanadium content, which in turn seriously affects the efficiency and effectiveness of subsequent acid leaching for vanadium extraction. Therefore, how to further improve the vanadium content of coal after alkaline extraction desilication has become a key problem that urgently needs to be solved in the field of vanadium extraction technology from coal. Summary of the Invention

[0006] The purpose of this invention is to provide the application of hydrotalcite as a vanadium-capturing agent in the desilication and vanadium extraction of solid waste shale coal, and a method for desilication and vanadium extraction of solid waste shale coal based on the structural memory effect of hydrotalcite, in order to solve the problems existing in the prior art. The method of this invention can significantly increase the vanadium content of the desilicationed solid waste shale coal, thereby meeting the vanadium content requirements of the shale coal vanadium extraction process, greatly improving the efficiency of the shale coal vanadium extraction process, and simultaneously realizing the resource utilization of solid waste shale coal.

[0007] To achieve the above objectives, the present invention provides the following solution:

[0008] One of the technical solutions of this invention is to provide an application of a vanadium-capturing agent in the desilication and vanadium extraction of solid waste coal, wherein the vanadium-capturing agent is hydrotalcite.

[0009] As a further preferred embodiment of the present invention, the hydrotalcite is at least one of magnesium aluminum hydrotalcite, calcium aluminum hydrotalcite, and zinc aluminum hydrotalcite.

[0010] This invention also provides a method for desiliconization and vanadium extraction from solid waste coal based on the structural memory effect of hydrotalcite, comprising the following steps:

[0011] (1) Mix and roast the shale and vanadium scavenging agent to obtain roasted shale;

[0012] (2) The roasted coal and inorganic alkali are mixed in a solvent, and the mixture is reacted at 80~95℃. The mixture is then filtered, washed and dried to obtain desilicationized coal.

[0013] The vanadium-capturing agent is hydrotalcite; the hydrotalcite is at least one selected from magnesium aluminum hydrotalcite, calcium aluminum hydrotalcite, and zinc aluminum hydrotalcite. In the method of the present invention, magnesium aluminum hydrotalcite is preferably used as the vanadium-capturing agent.

[0014] As a further preferred embodiment of the present invention, the crystallinity of the hydrotalcite is ≥85%.

[0015] As a further preferred embodiment of the present invention, the mass ratio of the coal and the vanadium-capturing agent is 1:(0.01~0.03) on a dry basis.

[0016] As a further preferred embodiment of the present invention, the temperature of the mixed calcination is 800~1100℃ and the time is 30~180min.

[0017] As a further preferred embodiment of the present invention, the inorganic base is at least one selected from sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate. In the method of the present invention, sodium hydroxide is preferably used as the inorganic base.

[0018] As a further preferred embodiment of the present invention, the solvent is water.

[0019] As a further preferred embodiment of the present invention, the mass ratio of the roasted coal, inorganic alkali and water is 1:(0.1~1):(4~8).

[0020] The filtrate obtained by filtration in step (2) of this invention is a sodium silicate solution; the filtrate can be used for the synthesis of zeolite molecular sieves / white carbon black, wet desulfurization of flue gas, and as a finished product for sale.

[0021] Hydrotalcite is an anionic layered bimetallic hydroxide with a unique "structural memory" effect. This invention addresses the vanadium loss problem in existing alkaline extraction and desilication methods for coal shale. It employs binary hydrotalcite as a vanadium-capturing agent. First, hydrotalcite is mixed with coal shale and roasted, activating the coal shale while simultaneously disrupting the hydrotalcite structure. Then, an alkaline solution is used to perform alkaline extraction on the roasted mixture. This removes silica species from the coal shale structure, and the vanadium-capturing agent (hydrotalcite) in the roasted mixture reconstructs its crystal structure through the "structural memory" effect, selectively adsorbing vanadium oxide anions (vanadium capture). This significantly reduces vanadium loss during alkaline extraction. Based on this technical concept, the method of this invention can significantly increase the vanadium content in desilicationized coal shale compared to existing alkaline extraction methods, fully meeting the vanadium content requirements of the raw material in coal shale vanadium extraction processes, greatly improving the efficiency of existing coal vanadium extraction, and simultaneously achieving the resource reuse of solid waste coal shale.

[0022] The present invention discloses the following technical effects:

[0023] This invention employs hydrotalcite-based vanadium-capturing agents to construct a synergistic treatment process involving the mixing and grinding of coal and the vanadium-capturing agent, high-temperature roasting, and alkaline reaction. Utilizing the structural memory effect of hydrotalcite, the crystal structure of hydrotalcite is destroyed during the roasting stage. Upon entering the alkaline reaction stage, the hydrotalcite structure is reconstructed and selectively adsorbs vanadium anions, thereby significantly reducing vanadium loss and effectively increasing the vanadium content of the desilication-treated coal. Simultaneously, it significantly reduces the silicon oxide content in the coal, effectively solving the technical challenge of simultaneously achieving desilication and vanadium retention, and laying the foundation for improved efficiency in subsequent acid leaching vanadium extraction processes.

[0024] The method of this invention can significantly increase the vanadium content of desilicationized coal, thereby meeting the vanadium content requirements of vanadium extraction processes from coal, and thus significantly improving the vanadium extraction efficiency of coal, realizing the resource utilization of solid waste coal. Furthermore, the method of this invention is simple, low-cost, and has good application prospects. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 The image shows the XRD pattern of the roasted coal prepared in Example 4 of this invention.

[0027] Figure 2 The image shows the XRD pattern of the desilicationized coal (C5) prepared in Example 4 of this invention. Detailed Implementation

[0028] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0029] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0030] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0031] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0032] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0033] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0034] In the method of the present invention, the roasting, filtering, washing and drying steps are all processes well known to those skilled in the art and are not specifically limited.

[0035] In the following embodiments and comparative examples of this invention, the coal used is industrial grade coal, and its main components and contents by mass fraction are: SiO2: 77.5%; V2O5: 4.5%; and the magnesium aluminum hydrotalcite (Mg6Al2(CO3)(OH)) used is... 16 • 4H2O (crystallization ≥ 85%) and sodium hydroxide were analytical grade reagents, both purchased from Sigma-Aldrich.

[0036] In the following embodiments and comparative examples of the present invention, XRD detection was performed using a D / max-2200PC X-ray diffractometer (XRD) manufactured by Rigaku Corporation of Japan, and elemental analysis of the samples was performed using a Rigaku ZSX Primus fluorescence spectrometer (XRF).

[0037] Example 1

[0038] (1) Raw material mixing and grinding: Weigh 100g of dry base coal and 1g of dry base magnesium aluminum hydrotalcite, mix the two thoroughly and then grind them to obtain mixed powder.

[0039] (2) High-temperature roasting activation: The mixed powder obtained in step (1) is placed in a roasting device and roasted at 850℃ for 180 minutes. After roasting, it is cooled to obtain roasted coal.

[0040] (3) Alkali reaction: Weigh 50g of roasted coal obtained in step (2), 5g of sodium hydroxide and 200g of water, add the three to the reaction vessel, and stir the reaction for 3h at a constant temperature of 80℃; after the reaction is completed, filter the reaction system to obtain filter residue and filtrate (the main component is sodium silicate, which can be used for subsequent resource utilization such as zeolite molecular sieve / white carbon black synthesis and wet desulfurization of flue gas); wash and dry the filter residue in sequence to finally obtain desiliconized coal (denoted as C1) and the filtrate is sodium silicate solution.

[0041] Example 2

[0042] (1) Raw material mixing and grinding: Weigh 100g of dry base coal and 1.5g of dry base magnesium aluminum hydrotalcite, mix the two thoroughly and then grind them to obtain mixed powder.

[0043] (2) High-temperature roasting activation: The mixed powder obtained in step (1) is placed in a roasting device and roasted at 900℃ for 150 min. After cooling, roasted coal is obtained.

[0044] (3) Alkali reaction: Weigh 50g of roasted coal obtained in step (2), 15g of sodium hydroxide and 250g of water, add the three to the reaction vessel, and stir the reaction for 2.5h at a constant temperature of 84℃. After the reaction is completed, filter the reaction system to obtain filter residue and filtrate (the main component is sodium silicate, which can be used for subsequent resource utilization such as zeolite molecular sieve / white carbon black synthesis and wet desulfurization of flue gas). Wash and dry the filter residue in sequence to finally obtain desiliconized coal (denoted as C2) and the filtrate is sodium silicate solution.

[0045] Example 3

[0046] (1) Raw material mixing and grinding: Weigh 100g of dry base coal and 2g of dry base magnesium aluminum hydrotalcite, mix the two thoroughly and then grind them to obtain mixed powder.

[0047] (2) High-temperature roasting activation: The mixed powder obtained in step (1) is placed in a roasting device and roasted at 950℃ for 110 minutes. After cooling, roasted coal is obtained.

[0048] (3) Alkali reaction: Weigh 50g of roasted coal obtained in step (2), 25g of sodium hydroxide and 300g of water, add the three to the reaction vessel, and stir the reaction for 2h at a constant temperature of 88℃; after the reaction is completed, filter the reaction system to obtain filter residue and filtrate (the main component is sodium silicate, which can be used for subsequent resource utilization such as zeolite molecular sieve / white carbon black synthesis and wet desulfurization of flue gas); wash and dry the filter residue in sequence to finally obtain desiliconized coal (denoted as C3) and the filtrate is sodium silicate solution.

[0049] Example 4

[0050] (1) Raw material mixing and grinding: Weigh 100g of dry base coal and 2.5g of dry base magnesium aluminum hydrotalcite, mix the two thoroughly and then grind them to obtain mixed powder.

[0051] (2) High-temperature roasting activation: The mixed powder obtained in step (1) is placed in a roasting device and roasted at 1000℃ for 70 minutes. After cooling, roasted coal is obtained.

[0052] (3) Alkali reaction: Weigh 50g of roasted coal obtained in step (2), 35g of sodium hydroxide and 350g of water, add the three to the reaction vessel, and stir the reaction for 1.5h at a constant temperature of 92℃. After the reaction is completed, filter the reaction system to obtain filter residue and filtrate (the main component is sodium silicate, which can be used for subsequent resource utilization such as zeolite molecular sieve / white carbon black synthesis and wet desulfurization of flue gas). Wash and dry the filter residue in sequence to finally obtain desilicationized coal (denoted as C4) and filtrate is sodium silicate solution.

[0053] Example 5

[0054] (1) Raw material mixing and grinding: Weigh 100g of dry base coal and 3g of dry base magnesium aluminum hydrotalcite, mix the two thoroughly and then grind them to obtain mixed powder.

[0055] (2) High-temperature roasting activation: The mixed powder obtained in step (1) is placed in a roasting device and roasted at 1050℃ for 30 minutes. After cooling, roasted coal is obtained.

[0056] (3) Alkali reaction: Weigh 50g of roasted coal obtained in step (2), 50g of sodium hydroxide and 400g of water, add the three to the reaction vessel, and stir the reaction for 1h under a constant temperature of 95℃; after the reaction is completed, filter the reaction system to obtain filter residue and filtrate (the main component is sodium silicate, which can be used for subsequent resource utilization such as zeolite molecular sieve / white carbon black synthesis and wet desulfurization of flue gas); wash and dry the filter residue in sequence to finally obtain desiliconized coal (denoted as C5).

[0057] Comparative Example 1

[0058] (1) Raw material mixing and grinding: 100g of dry base coal is roasted at 850℃ for 180min. After roasting, it is cooled to obtain roasted coal.

[0059] (2) Alkali reaction: Weigh 50g of roasted coal obtained in step (1), 5g of sodium hydroxide and 200g of water, add the three to the reaction vessel, and stir the reaction for 3h at a constant temperature of 80℃; after the reaction is completed, filter the reaction system to obtain filter residue and filtrate; wash and dry the filter residue in sequence to finally obtain desiliconized coal (denoted as D1).

[0060] Comparative Example 2

[0061] (1) Raw material mixing and grinding: 100g of dry base coal is roasted at 950℃ for 110min. After roasting, it is cooled to obtain roasted coal.

[0062] (2) Alkali reaction: Weigh 50g of roasted coal obtained in step (1), 25g of sodium hydroxide and 300g of water, add the three to the reaction vessel, and stir the reaction for 2h at a constant temperature of 88℃; after the reaction is completed, filter the reaction system to obtain filter residue and filtrate; wash and dry the filter residue in sequence to finally obtain desilicationized coal (denoted as D2).

[0063] Comparative Example 3

[0064] (1) Raw material mixing and grinding: 100g of dry base coal is roasted at 1050℃ for 30min, and then cooled to obtain roasted coal.

[0065] (2) Alkali reaction: Weigh 50g of roasted coal obtained in step (1), 50g of sodium hydroxide and 400g of water, add the three to the reaction vessel, and stir the reaction for 1h under a constant temperature of 95℃; after the reaction is completed, filter the reaction system to obtain filter residue and filtrate; wash and dry the filter residue in sequence to finally obtain desiliconized coal (denoted as D3).

[0066] Figure 1 The image shows the XRD pattern of the roasted coal prepared in Example 4 of this invention. Figure 2 The image shows the XRD pattern of the desilicationized coal (C5) prepared in Example 4 of this invention.

[0067] Depend on Figure 1 It can be seen that the roasted coal sample prepared in Example 4 did not show the characteristic diffraction peaks of magnesium aluminum hydrotalcite, indicating that the crystal structure of the vanadium-capturing magnesium aluminum hydrotalcite was destroyed during the activation process of roasting; Figure 2 It can be seen that after alkaline extraction and desilication treatment, the desilicationized coal prepared in Example 4 showed clear diffraction peaks characteristic of magnesium aluminum hydrotalcite, indicating that the crystal structure of magnesium aluminum hydrotalcite prepared by the vanadium fixation agent was well reconstructed based on the "structural memory" effect.

[0068] The silica and vanadium oxide contents of the desilicationized coal prepared in Examples 1-5 and Comparative Examples 1-3 are shown in Table 1.

[0069] Table 1

[0070]

[0071] As shown in Table 1, compared with the existing alkaline extraction methods for preparing desilicationized coal samples (D1~D3), the desilicationized coal samples (C1~C5) prepared by the method of the present invention all showed significantly lower silica content and higher vanadium oxide content, indicating that the method of the present invention has better desilication effect and lower vanadium loss.

[0072] The method of this invention can significantly increase the vanadium content of desilicationized coal, thereby meeting the vanadium content requirements of vanadium extraction processes from coal, and thus significantly improving the vanadium extraction efficiency of coal, realizing the resource utilization of solid waste coal. Furthermore, the method of this invention is simple, low-cost, and has good application prospects.

[0073] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. The application of a vanadium-capturing agent in the desilication and vanadium extraction of solid waste coal shale, characterized in that, The vanadium-capturing agent is hydrotalcite.

2. The application according to claim 1, characterized in that, The hydrotalcite is at least one of magnesium aluminum hydrotalcite, calcium aluminum hydrotalcite, and zinc aluminum hydrotalcite.

3. A method for desiliconization and vanadium extraction from solid waste coal based on the structural memory effect of hydrotalcite, characterized in that, Includes the following steps: (1) Mix and roast the shale and vanadium scavenging agent to obtain roasted shale; (2) The roasted coal and inorganic alkali are mixed in a solvent, and the mixture is reacted at 80~95℃. The mixture is then filtered, washed, and dried to obtain desilicationized coal. The vanadium-capturing agent is hydrotalcite; the hydrotalcite is at least one of magnesium aluminum hydrotalcite, calcium aluminum hydrotalcite, and zinc aluminum hydrotalcite.

4. The method for desiliconization and vanadium extraction from solid waste coal based on the structural memory effect of hydrotalcite as described in claim 3, characterized in that, The crystallinity of the hydrotalcite is ≥85%.

5. The method for desiliconization and vanadium extraction from solid waste coal based on the structural memory effect of hydrotalcite as described in claim 3, characterized in that, On a dry basis, the mass ratio of the coal and the vanadium-capturing agent is 1:(0.01~0.03).

6. The method for desiliconization and vanadium extraction from solid waste coal based on the structural memory effect of hydrotalcite as described in claim 3, characterized in that, The temperature for the mixed roasting is 800~1100℃, and the time is 30~180 min.

7. The method for desiliconization and vanadium extraction from solid waste coal based on the structural memory effect of hydrotalcite as described in claim 3, characterized in that, The inorganic base is at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate.

8. The method for desiliconization and vanadium extraction from solid waste coal based on the structural memory effect of hydrotalcite as described in claim 3, characterized in that, The solvent is water.

9. The method for desiliconization and vanadium extraction from solid waste coal based on the structural memory effect of hydrotalcite as described in claim 8, characterized in that, The mass ratio of the roasted coal, inorganic alkali and water is 1:(0.1~1):(4~8).

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