A solid waste stone coal desiliconization and vanadium extraction method based on synergistic effect of a vanadium fixing agent and an organic-inorganic composite base

Abstract

The application discloses a kind of solid waste stone coal desilication vanadium extraction methods based on solid vanadium agent and organic-inorganic composite base synergistic effect, and relates to solid waste resource utilization technical field.The application first mixes and calcines stone coal and solid vanadium agent, mixes the obtained calcined stone coal with organic-inorganic composite base, and carries out alkali extraction desilication.The method of the application can greatly improve the vanadium content after stone coal desilication, so as to meet the requirement of stone coal vanadium extraction to raw material vanadium content, and then can significantly improve the efficiency of stone coal vanadium extraction process, efficiently realize the resource utilization of solid waste stone coal.The method of the application is simple, low in cost, and has good application prospect.

Description

Technical Field

[0001] This invention relates to the field of solid waste resource utilization technology, and in particular to a desiliconization method for increasing the vanadium content of solid waste coal. Background Technology

[0002] Shale coal is a low-carbon, low-calorific-value, low-grade solid waste anthracite, and also a low-grade polymetallic symbiotic mineral, with silicon dioxide as its main component. Shale coal is also an important vanadium resource, and vanadium extraction technology from shale coal, widely used in steel, chemical, and energy storage battery industries, is a key technology for extracting vanadium from vanadium-bearing shale coal.

[0003] In recent years, with the rapid development of the new energy industry, the market demand for vanadium has continued to grow, making vanadium extraction from coal shale increasingly important. Currently, acid leaching is a common process for vanadium extraction from coal shale. This process 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 raw material. Alkali extraction is currently the mainstream desilication method.

[0004] The conventional alkaline extraction desilication process is as follows: first, the coal is roasted at high temperature to activate the silicon oxide in the coal, and then the roasted coal is treated with an alkaline solution to remove the silicon oxide species. However, the existing alkaline extraction desilication method has two major problems that seriously restrict the subsequent vanadium extraction effect: (1) Limited desilication efficiency: During the high-temperature roasting and activation process, the silicon oxide species in the coal structure will undergo surface dehydroxylation reaction, and the residual carbon in the coal will enhance the hydrophobicity of the coal surface after roasting, making it difficult for the roasted coal to fully contact and react with the subsequent alkaline solution, which directly affects the desilication efficiency; (2) Vanadium loss: Vanadium oxide in coal is an acidic oxide, which will inevitably react with the alkali during the alkaline extraction process, 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 increase 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 a desiliconization method for increasing the vanadium content in solid waste shale coal, thereby solving the problems existing in the prior art. This invention can significantly increase the vanadium content in the desiliconized solid waste shale coal, thus meeting the vanadium content requirements of the shale coal vanadium extraction process, ensuring the vanadium extraction efficiency of the shale coal, 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] This invention provides a method for desilication and vanadium extraction from solid waste coal based on the synergistic effect of vanadium-fixing agents and organic-inorganic composite alkalis, comprising the following steps:

[0009] (1) Mix and grind the shale and vanadium-fixing agent, and then roast them to obtain roasted shale;

[0010] (2) The roasted coal, inorganic alkali and organic alkali are mixed in a solvent, and the mixture is stirred and reacted at 80~95℃. After the reaction is completed, the mixture is filtered, and the resulting filter residue is washed and dried to obtain desiliconized coal.

[0011] The vanadium-fixing agent is at least one selected from lanthanum chloride, lanthanum nitrate, lanthanum sulfate, lanthanum carbonate, lanthanum oxide, yttrium chloride, yttrium nitrate, yttrium sulfate, yttrium carbonate, yttrium oxide, magnesium chloride, magnesium nitrate, magnesium sulfate, magnesium carbonate, and magnesium oxide.

[0012] In the method of the present invention, the vanadium-fixing agent is preferably lanthanum oxide.

[0013] As a further preferred embodiment of the present invention, the mass ratio of the coal and the vanadium-fixing agent is 1:(0.01~0.03) on a dry basis.

[0014] As a further preferred embodiment of the present invention, the temperature of the mixed calcination is 900~1100℃ and the time is 10~120min.

[0015] 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.

[0016] As a further preferred embodiment of the present invention, the organic base is at least one selected from tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, and tetrabutylammonium hydroxide. In the method of the present invention, the organic base is preferably tetraethylammonium hydroxide.

[0017] As a further preferred embodiment of the present invention, the solvent is water.

[0018] As a further preferred embodiment of the present invention, the mass ratio of the roasted coal, inorganic alkali, organic alkali and water is 1:(0.1~1):(0.01~0.1):(4~8).

[0019] The filtrate obtained after 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.

[0020] This invention introduces a vanadium-fixing agent containing alkaline elements into the roasting and activation system of shale coal. During roasting, the alkaline elements in the vanadium-fixing agent can fully react with the acidic vanadium oxides in the shale coal to generate chemically stable vanadate compounds. These compounds are less likely to react with alkali in the subsequent alkaline extraction environment, fundamentally blocking the dissolution and loss pathway of vanadium (mainly V₂O₅). Compared to existing alkaline extraction methods that suffer from insufficient vanadium content in desilicationized shale coal due to vanadium loss, this invention can significantly improve the vanadium grade of desilicationized shale coal, fully meeting the core requirements of vanadium content in raw materials for shale coal vanadium extraction processes, and laying a crucial foundation for improving the efficiency of subsequent acid leaching vanadium extraction.

[0021] This invention employs an organic-inorganic composite alkali system during alkali extraction. The addition of organic alkali plays a dual role: on the one hand, organic alkali can synergistically enhance the overall alkalinity of the reaction system with inorganic alkali, providing a more suitable chemical environment for the reaction of silicon dioxide with alkali and accelerating the dissolution and removal of silicon dioxide; on the other hand, the amphiphilic cations contained in organic alkali can effectively regulate the interfacial characteristics of roasted coal. Addressing the hydrophobicity problem caused by surface dehydroxylation and residual carbon in roasted coal after high-temperature roasting, the amphiphilic cations can improve the interfacial contact state between roasted coal and alkali solution, promoting thorough mixing and reaction between the two. This completely solves the technical problem of insufficient solid-liquid contact leading to low desiliconization efficiency in existing methods, significantly improving the silicon dioxide removal rate.

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

[0023] To address the significant technical problems of low desilication efficiency and vanadium loss in existing alkali extraction and desilication methods for coal shale, this invention introduces a vanadium-fixing agent containing alkaline elements into the coal shale roasting activation system and adopts an organic-inorganic composite alkali system during the alkali extraction process. Through the synergistic application of these two key technologies, a dual technological breakthrough has been achieved in terms of both desilication efficiency and vanadium retention rate.

[0024] This invention not only significantly improves the overall efficiency of vanadium extraction from coal shale and reduces raw material consumption and costs in the vanadium extraction process, but also enables the high-value resource reuse of solid waste coal shale. Solid waste coal shale, which was originally difficult to utilize efficiently due to its low vanadium content and challenging desiliconization process, can be transformed into high-quality vanadium extraction raw material after processing with this invention. Furthermore, the filtrate produced by alkaline extraction (such as sodium silicate solution) can be further used in zeolite molecular sieve production, silica synthesis, or wet flue gas desulfurization, demonstrating both significant technological innovation and excellent economic and environmental benefits. 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 desilicationized coal C1 prepared in Example 1 of this invention.

[0027] Figure 2 The image shows the XRD pattern of desilicationized coal D1 prepared in Comparative Example 1 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 particularly limited.

[0035] In the following examples and comparative examples of the present invention, the coal used is industrial grade coal, and the main components and contents by mass fraction are: SiO2: 77.5%; V2O5: 4.5%; the lanthanum oxide, sodium hydroxide and tetraethylammonium hydroxide (TEAOH, 35%) used are all analytical grade reagents 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: Take 100g of dry base coal and 1g of lanthanum oxide and place them in a grinding device. Mix them thoroughly and grind them into a uniform powder to ensure that the coal and lanthanum oxide are evenly dispersed to obtain a mixed powder.

[0039] (2) Calcination of mixed powder: The mixed powder obtained in step (1) is transferred to a calcination device and calcined at 900°C for 120 minutes. After calcination, it is cooled to obtain calcined coal.

[0040] (3) Compound alkali extraction desilication: Weigh 50g of roasted coal obtained in step (2), 5g of sodium hydroxide, 1.43g of tetraethylammonium hydroxide (TEAOH) and 250g of water, mix them, stir the mixture at 80℃ for 3h, filter after the reaction, and obtain filtrate (mainly sodium silicate, which can be used for subsequent resource utilization such as zeolite molecular sieve / white carbon black synthesis and flue gas wet desulfurization) and filter residue respectively; wash the obtained filter residue to remove residual alkali and soluble impurities, and finally dry the washed filter residue to obtain desilicationated coal C1.

[0041] Example 2

[0042] (1) Raw material mixing and grinding: Take 100g of dry base coal and 1.5g of lanthanum oxide and place them in a grinding device, mix them thoroughly and grind them into a uniform powder to ensure that the coal and lanthanum oxide are evenly dispersed to obtain a mixed powder;

[0043] (2) Calcination of mixed powder: The mixed powder obtained in step (1) is transferred to a calcination device and calcined at a temperature of 950°C for 100 min. After calcination, it is cooled to obtain calcined coal.

[0044] (3) Compound alkali extraction desilication: Weigh 50g of roasted coal obtained in step (2), 15g of sodium hydroxide, 4.28g of tetraethylammonium hydroxide (TEAOH) and 250g of water, mix them, and stir the mixture at 84℃ for 2.5h. After the reaction is completed, filter it to obtain filtrate (mainly 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) and filter residue. Wash the obtained filter residue to remove residual alkali and soluble impurities. Finally, dry the washed filter residue to obtain desilicationized coal C2.

[0045] Example 3

[0046] (1) Raw material mixing and grinding: Take 100g of dry base coal and 2g of lanthanum oxide and place them in a grinding equipment. Mix them thoroughly and grind them into a uniform powder to ensure that the coal and lanthanum oxide are evenly dispersed to obtain a mixed powder.

[0047] (2) Calcination of mixed powder: The mixed powder obtained in step (1) is transferred to a calcination device and calcined at a temperature of 1000℃ for 70 minutes. After calcination, it is cooled to obtain calcined coal.

[0048] (3) Compound alkali extraction desilication: Weigh 50g of roasted coal obtained in step (2), 25g of sodium hydroxide, 7.14g of tetraethylammonium hydroxide (TEAOH) and 300g of water, mix them, and stir the mixture at 88℃ for 2.5h. After the reaction is completed, filter it to obtain filtrate (mainly sodium silicate, which can be used for subsequent resource utilization such as zeolite molecular sieve / white carbon black synthesis and flue gas wet desulfurization) and filter residue. Wash the obtained filter residue to remove residual alkali and soluble impurities. Finally, dry the washed filter residue to obtain desilicationized coal C3.

[0049] Example 4

[0050] (1) Raw material mixing and grinding: Take 100g of dry base coal and 2.5g of lanthanum oxide and place them in a grinding device. Mix and grind them thoroughly until they are uniform powder to ensure that the coal and lanthanum oxide are evenly dispersed and mixed powder is obtained.

[0051] (2) Calcination of mixed powder: The mixed powder obtained in step (1) is transferred to a calcination device and calcined at a temperature of 1050℃ for 40 minutes. After calcination, it is cooled to obtain calcined coal.

[0052] (3) Compound alkali extraction desilication: Weigh 50g of roasted coal obtained in step (2), 35g of sodium hydroxide, 10.01g of tetraethylammonium hydroxide (TEAOH) and 350g of water, mix them, and stir the mixture at 92℃ for 1.5h. After the reaction is completed, filter it to obtain filtrate (mainly sodium silicate, which can be used for subsequent resource utilization such as zeolite molecular sieve / white carbon black synthesis and flue gas wet desulfurization) and filter residue. Wash the obtained filter residue to remove residual alkali and soluble impurities. Finally, dry the washed filter residue to obtain desilicationized coal C4.

[0053] Example 5

[0054] (1) Raw material mixing and grinding: Take 100g of dry base coal and 3g of lanthanum oxide and place them in a grinding equipment. Mix them thoroughly and grind them into a uniform powder to ensure that the coal and lanthanum oxide are evenly dispersed to obtain a mixed powder.

[0055] (2) Calcination of mixed powder: The mixed powder obtained in step (1) is transferred to a calcination device and calcined at 1100℃ for 10 minutes. After calcination, it is cooled to obtain calcined coal.

[0056] (3) Compound alkali extraction desilication: Weigh 50g of roasted coal obtained in step (2), 50g of sodium hydroxide, 14.2g of tetraethylammonium hydroxide (TEAOH) and 400g of water, mix them, stir the mixture at 95℃ for 1h, filter after the reaction, and obtain filtrate (mainly sodium silicate, which can be used for subsequent resource utilization such as zeolite molecular sieve / white carbon black synthesis and flue gas wet desulfurization) and filter residue respectively; wash the obtained filter residue to remove residual alkali and soluble impurities, and finally dry the washed filter residue to obtain desilicationated coal C5.

[0057] Comparative Example 1

[0058] (1) Raw material grinding and roasting: 100g of dry base coal is ground in a grinding equipment and then roasted at 900℃ for 120min to obtain roasted coal;

[0059] (2) Alkali extraction desilication: Weigh 50g of roasted coal obtained in step (1), 6.43g of sodium hydroxide and 200g of water, mix them, stir the mixture at 80℃ for 3h, filter after the reaction, and obtain filtrate and filter residue respectively; wash the obtained filter residue to remove residual alkali and soluble impurities, and finally dry the washed filter residue to obtain desilication coal D1.

[0060] Comparative Example 2

[0061] (1) Raw material grinding and roasting: 100g of dry base coal is ground in a grinding equipment and then roasted at 1000℃ for 70min to obtain roasted coal;

[0062] (2) Alkali extraction desilication: Weigh 50g of roasted coal obtained in step (1), 32.14g of sodium hydroxide and 300g of water, mix them, stir the mixture at 88℃ for 2.5h, filter after the reaction, and obtain filtrate and filter residue respectively; wash the obtained filter residue to remove residual alkali and soluble impurities, and finally dry the washed filter residue to obtain desilication coal D2.

[0063] Comparative Example 3

[0064] (1) Raw material grinding and roasting: 100g of dry base coal is ground in a grinding equipment and then roasted at 1100℃ for 10min to obtain roasted coal;

[0065] (2) Alkali extraction desilication: Weigh 50g of roasted coal obtained in step (1), 64.2g of sodium hydroxide and 400g of water, mix them, stir the mixture at 95℃ for 1h, filter after the reaction, and obtain filtrate and filter residue respectively; wash the obtained filter residue to remove residual alkali and soluble impurities, and finally dry the washed filter residue to obtain desilication coal D3.

[0066] Comparative Example 4

[0067] (1) Raw material mixing and grinding: Take 100g of dry base coal and 1.5g of lanthanum oxide (as a vanadium fixative) and place them in a grinding equipment. Mix them thoroughly and grind them into a uniform powder to ensure that the coal and lanthanum oxide are evenly dispersed to obtain a mixed powder.

[0068] (2) Calcination of mixed powder: The mixed powder obtained in step (1) is transferred to a calcination device and calcined at a temperature of 950°C for 100 min. After calcination, it is cooled to obtain calcined coal.

[0069] (3) Alkali extraction desilication: Weigh 50g of roasted coal obtained in step (2), 19.28g of sodium hydroxide and 250g of water, mix them, and stir the mixture at 84℃ for 2.5h. After the reaction is completed, filter it to obtain filtrate (mainly sodium silicate, which can be used for subsequent resource utilization such as zeolite molecular sieve / white carbon black synthesis and flue gas wet desulfurization) and filter residue. Wash the obtained filter residue to remove residual alkali and soluble impurities. Finally, dry the washed filter residue to obtain desilication coal D4.

[0070] Comparative Example 5

[0071] (1) Raw material grinding and roasting: 100g of dry base coal is ground in a grinding equipment and then roasted at 1050℃ for 40min to obtain roasted coal;

[0072] (2) Alkali extraction desilication: Weigh 50g of roasted coal obtained in step (1), 40.01g of sodium hydroxide, 10.01g of tetraethylammonium hydroxide (TEAOH) and 350g of water, mix them, and stir the mixture at 92℃ for 1.5h. After the reaction is completed, filter it to obtain filtrate and filter residue respectively. Wash the obtained filter residue to remove residual alkali and soluble impurities. Finally, dry the washed filter residue to obtain desilication coal D5.

[0073] Figure 1 The image shows the XRD pattern of desilicationized coal C1 prepared in Example 1 of this invention. Figure 2 The image shows the XRD pattern of desilicationized coal D1 prepared in Comparative Example 1 of this invention.

[0074] Depend on Figure 1 and Figure 2 It can be seen that the desiliconized coal samples prepared in Example 1 and Comparative Example 1 both showed characteristic diffraction peaks belonging to silica crystals, indicating that both contained a certain amount of silica in their structures. Compared with the sample in Comparative Example 1, the silica diffraction peak intensity of the desiliconized coal sample prepared in Example 1 was significantly lower, indicating that it had a significantly lower silica content, which fully demonstrates the excellent desiliconization effect of the method of the present invention.

[0075] The silica and vanadium oxide contents of the desilicationized coal prepared in Examples 1-5 and Comparative Examples 1-5 are shown in Table 1.

[0076] Table 1

[0077]

[0078] As shown in Table 1, compared with the desilication of coal samples (D1~D3) prepared by the existing alkaline extraction method, the desilication of 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 showed better desilication and vanadium retention effects. In addition, compared with the sample using only vanadium fixation agent (D4) and the sample using only alkaline extraction (D5), the desilication of coal samples prepared by the method of the present invention all had significantly lower silica content and higher vanadium oxide content, indicating that there is a significant "synergistic effect" between "vanadium fixation agent" and "alkaline extraction" in the method of the present invention, and only by using them simultaneously can the best desilication and vanadium retention effects be achieved.

[0079] The method of this invention can significantly increase the vanadium content of desilicationized coal, thereby meeting the requirements for vanadium content in raw materials for vanadium extraction from coal, and thus significantly improving the efficiency of the vanadium extraction process, achieving efficient resource utilization of solid waste coal. Furthermore, the method of this invention is simple, low-cost, and has good application prospects.

[0080] 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. A method for desilication and vanadium extraction from solid waste coal based on the synergistic effect of vanadium-fixing agents and organic-inorganic composite alkalis, characterized in that, Includes the following steps: (1) Mix and grind the shale and vanadium-fixing agent, and then roast them to obtain roasted shale; (2) The roasted coal, inorganic alkali and organic alkali are mixed in water, and the mixture is reacted at 80~95℃. After the reaction is completed, the mixture is filtered, and the resulting filter residue is washed and dried to obtain desiliconized coal. The vanadium-fixing agent is at least one selected from lanthanum chloride, lanthanum nitrate, lanthanum sulfate, lanthanum carbonate, lanthanum oxide, yttrium chloride, yttrium nitrate, yttrium sulfate, yttrium carbonate, yttrium oxide, magnesium chloride, magnesium nitrate, magnesium sulfate, magnesium carbonate, and magnesium oxide. The temperature for the mixed roasting is 900~1100℃, and the time is 10~120 min; The inorganic base is at least one of sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate; The organic base is at least one selected from tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, and tetrabutylammonium hydroxide; The mass ratio of the roasted coal, inorganic alkali, organic alkali and water is 1:(0.1~1):(0.01~0.1):(4~8).

2. The method for desilication and vanadium extraction from solid waste coal based on the synergistic effect of vanadium-fixing agent and organic-inorganic composite alkali according to claim 1, characterized in that, On a dry basis, the mass ratio of the coal and the vanadium-fixing agent is 1:(0.01~0.03).

Images