Hydrotalcite as a vanadium capture agent in the application of solid waste stone coal desilication and vanadium extraction and a solid waste stone coal desilication and vanadium extraction method based on the structure memory effect of hydrotalcite

Abstract

The application discloses application of hydrotalcite as a vanadium capturing agent in desiliconization and vanadium extraction of solid waste stone coal and a solid waste stone coal desiliconization and vanadium extraction method based on a structure memory effect of hydrotalcite, and relates to the technical field of solid waste resource utilization. The application utilizes the structure memory effect of hydrotalcite and applies the hydrotalcite to desiliconization and vanadium extraction of solid waste stone coal, and the steps include: mixing and calcining stone coal and a vanadium capturing agent to obtain calcined stone coal, mixing the calcined stone coal and an inorganic alkali in a solvent, and then reacting at 80-95 DEG C to obtain desiliconized stone coal. The application can significantly increase the vanadium content of the desiliconized stone coal, thereby meeting the content requirement of raw vanadium for a stone coal vanadium extraction process, and can significantly improve the vanadium extraction efficiency of the stone coal, and realize resource utilization of the solid waste stone coal. Meanwhile, the method has simple process, low cost and good application prospect.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of solid waste resource utilization, in particular to application of hydrotalcite as a vanadium capturing agent in solid waste stone coal desilication and vanadium extraction and a solid waste stone coal desilication and vanadium extraction method based on a structure memory effect of hydrotalcite. BACKGROUND

[0002] Stone-like coal is a low-quality solid waste anthracite with low carbon content and low calorific value, and is also a low-grade polymetallic symbiotic ore, and the main component is silicon oxide. As an important vanadium resource, stone coal is the core raw material of stone coal vanadium extraction technology, and the technology is widely used in the fields of steel, chemical industry, energy storage battery and the like, and can extract the key vanadium element from vanadium-containing stone coal.

[0003] In recent years, with the rapid development of the new energy industry, the market demand for vanadium continues to grow, and the technical value and industrial importance of stone coal vanadium extraction are increasingly prominent. At present, the acid leaching method is a commonly used process for stone coal vanadium extraction, which can make vanadium dissolve by impregnating vanadium-containing stone coal with acid solution, and then obtain finished vanadium through a separation step. However, in order to improve the acid leaching vanadium extraction efficiency, the stone coal raw material usually needs to be pretreated to remove the silicon oxide (i.e. desilication treatment) so as to increase the vanadium content (grade) of the stone coal raw material, and the alkali extraction method is the current mainstream desilication method.

[0004] The process of conventional alkali extraction desilication is as follows: first, the stone coal is subjected to high-temperature roasting, the silicon oxide in the stone coal is activated through high-temperature activation, and then the roasted stone coal is treated with an alkali solution to remove the silicon oxide species. However, the existing alkali extraction desilication method has two key problems which seriously restrict the subsequent vanadium extraction effect: first, the desilication efficiency is limited, during the high-temperature roasting activation process, the silicon oxide species in the stone coal structure will undergo surface dehydroxylation reaction, and the residual carbon in the stone coal will enhance the hydrophobicity of the surface of the roasted stone coal, which leads to the difficulty of the roasted stone coal in fully contacting and reacting with the subsequent alkali solution, directly affecting the desilication efficiency; second, vanadium element loss, the vanadium oxide in the stone coal belongs to acidic oxide, which will inevitably react with alkali during the alkali extraction process, causing the loss of vanadium in the form of V2O5.

[0005] The above problems result in the difficulty of the existing alkali extraction desilication method in obtaining desilicated stone coal with high vanadium content, which seriously affects the efficiency and effect of the subsequent acid leaching vanadium extraction, therefore, how to further improve the vanadium content of the stone coal after alkali extraction desilication has become a key problem to be solved in the current stone coal vanadium extraction technology field. SUMMARY

[0006] The application aims to provide an application of hydrotalcite as a vanadium capturing agent in a solid waste stone coal desilication and vanadium extraction method based on a structure memory effect of hydrotalcite, so as to solve the problems in the prior art. The method can significantly improve the vanadium content of the solid waste stone coal after desilication, thereby meeting the demand of the stone coal vanadium extraction process for the vanadium content of raw materials, greatly improving the efficiency of the stone coal vanadium extraction process, and realizing the resource utilization of the solid waste stone coal.

[0007] To achieve the above-mentioned object, the application provides the following solutions.

[0008] One of the technical solutions of the application provides an application of a vanadium capturing agent in a solid waste stone coal desilication and vanadium extraction method, wherein the vanadium capturing agent is hydrotalcite.

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

[0010] The application further provides a solid waste stone coal desilication and vanadium extraction method based on a structure memory effect of hydrotalcite, comprising the following steps.

[0011] (1) mixing and roasting stone coal and a vanadium capturing agent to obtain roasted stone coal;

[0012] (2) mixing the roasted stone coal and an inorganic base in a solvent, reacting the mixed system at 80-95 DEG C, filtering, washing and drying to obtain desilicated stone coal;

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

[0014] As a further preferred embodiment of the application, the crystallinity of the hydrotalcite is greater than or equal to 85%.

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

[0016] As a further preferred embodiment of the application, the temperature of the mixing and roasting is 800-1100 DEG C, and the time is 30-180 min.

[0017] As a further preferred embodiment of the application, the inorganic base is at least one of sodium hydroxide, potassium hydroxide, sodium carbonate and potassium carbonate. In the method, the inorganic base is preferably sodium hydroxide.

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

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

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

[0021] The hydrotalcite is a kind of anionic layered double metal hydroxide, and has a unique'structure memory' effect. The present application aims at the vanadium loss problem existing in the existing stone coal alkali extraction desilication method, and uses binary hydrotalcite as a vanadium capturing agent. First, the hydrotalcite is mixed and calcined with the stone coal, so as to activate the stone coal and destroy the structure of the hydrotalcite. Then, the calcined mixed sample is treated by alkali extraction, so as to remove the silicon oxide species in the structure of the stone coal, and the vanadium capturing agent (hydrotalcite) in the calcined mixed sample reconstructs the crystal structure of the hydrotalcite by the'structure memory' effect and selectively adsorbs the vanadyl negative ion (captures vanadium), so that the vanadium loss in the alkali extraction process can be significantly reduced. Based on the above technical concept, the method of the present application can significantly increase the vanadium content in the desilicated stone coal compared with the existing alkali extraction method, can fully meet the requirement of the raw material vanadium content for the stone coal vanadium extraction process, and can greatly improve the existing stone coal vanadium extraction efficiency, while realizing the resource recycling of the solid waste stone coal.

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

[0023] The present application uses a hydrotalcite type vanadium capturing agent to construct a synergistic treatment process of mixing and grinding the stone coal with the vanadium capturing agent, high-temperature calcination and alkali reaction. The structure memory effect of the hydrotalcite is used to destroy the crystal structure of the hydrotalcite in the calcination link. After entering the alkali reaction link, the structure of the hydrotalcite is reconstructed and selectively adsorbs the vanadyl negative ion, so as to greatly reduce the loss of vanadium element, effectively improve the vanadium content of the desilicated stone coal, significantly reduce the content of silicon oxide in the stone coal, effectively solve the technical problem that it is difficult to balance desilication and vanadium preservation, and lay a foundation for the efficiency improvement of the subsequent acid leaching vanadium extraction process.

[0024] The method of the present application can significantly improve the vanadium content of the desilicated stone coal, so as to meet the requirement of the raw material vanadium content for the stone coal vanadium extraction process, and then can significantly improve the vanadium extraction efficiency of the stone coal, and realize the resource utilization of the solid waste stone coal. At the same time, the method of the present application is simple in process and low in cost, and has a good application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed in the embodiments will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0026] Figure 1 XRD pattern of the calcined stone coal prepared in Example 4 of the present application;

[0027] Figure 2 XRD pattern of the desilicated stone coal (C4) prepared in Example 4 of the present application. DETAILED DESCRIPTION

[0028] The detailed description set forth below is intended as a description of various example embodiments of the application and is not intended to represent the only embodiments in which the application can be practiced. The term "exemplary" used throughout this description means "serving as an example, instance, or illustration," and should not necessarily be construed as preferred or advantageous over other examples. In describing the various example embodiments, specific terminology is used for the sake of clarity.

[0029] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. In addition, any numerical range recited herein is intended to include all sub-ranges of the same numerical precision subsumed therein. In addition, all ranges format include the endpoints.

[0030] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice of the present application, the preferred methods and materials are described herein. All patents, patent applications, publications, and descriptions mentioned herein are incorporated by reference in their entirety for the disclosure and

[0031] Many modifications and variations of this application can be made in the light of the above teachings without departing from the spirit and scope thereof, and it is to be understood that all such modifications and variations warrant the patentable subject matter under the patent statutes. Other embodiments of the application will be apparent to those skilled in the art from consideration of the specification and practice of the application disclosed herein. For example, the specification and examples provide one of skill with a complete disclosure and concept for carrying out the application. It is not intended to be limited by the format of the exemplified embodiments, but rather, the intention is to convey the spirit and scope of the application.

[0032] As used herein, the terms "comprise", "comprising", "include", "including", "have", "having" and the like are open-ended and do not exclude additional elements or steps.

[0033] It should be noted that the present application does not describe in detail the conventional operation means in the art, and is not the focus of the present application.

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

[0035] In the following examples and comparative examples of the present application, the stone coal used is an industrial product stone coal, the main components and contents of which are as follows: SiO2: 77.5%; V2O5: 4.5% by mass. The magnesium-aluminum hydrotalcite (Mg6Al2(CO3)(OH) 16 • 4H2O, crystallinity ≥ 85%) and sodium hydroxide, both of which are analytical reagents purchased from Sigma-Aldrich Reagent Company.

[0036] In the following examples and comparative examples of the present application, XRD detection is performed using a D / max-2200PC X-ray diffractometer (XRD) produced by Rigaku Company of Japan, and sample elemental analysis is performed using a ZSX Primus fluorescence spectrometer (XRF) produced by Rigaku Company.

[0037] Example 1

[0038] (1) Raw material mixing and grinding: 100 g of dry-based stone coal and 1 g of dry-based magnesium-aluminum hydrotalcite are weighed and mixed thoroughly, and then ground to obtain a mixed powder.

[0039] (2) High-temperature calcination and activation: the mixed powder obtained in step (1) is placed in a calcination device and calcined at a temperature of 850°C for 180 min, and then cooled to obtain calcined stone coal.

[0040] (3) Alkali solution reaction: 50 g of the calcined stone coal obtained in step (2), 5 g of sodium hydroxide and 200 g of water are weighed and added to a reaction container, and stirred at a constant temperature of 80°C for 3 h. After the reaction is completed, the reaction system is filtered to obtain a filter residue and a filtrate (mainly composed of sodium silicate, which can be used for subsequent resource utilization such as zeolite molecular sieve / white carbon black synthesis, flue gas wet desulfurization, etc.). The filter residue is sequentially washed and dried to obtain desilicated stone coal (denoted as C1), and the filtrate is a sodium silicate solution.

[0041] Example 2

[0042] (1) Raw material mixing and grinding: 100 g of dry-based stone coal and 1.5 g of dry-based magnesium-aluminum hydrotalcite are weighed and mixed thoroughly, and then ground to obtain a mixed powder.

[0043] (2) High-temperature calcination and activation: the mixed powder obtained in step (1) is placed in a calcination device and calcined at a temperature of 900°C for 150 min, and then cooled to obtain calcined stone coal.

[0044] (3) Alkali solution reaction: 50 g of the calcined stone coal obtained in step (2), 15 g of sodium hydroxide and 250 g of water were weighed and added into a reaction container, and stirred at 84°C for 2.5 h. After the reaction, the reaction system was filtered to obtain a filter residue and a filtrate (main component: sodium silicate, which can be used for subsequent resource utilization such as zeolite molecular sieve / silica synthesis, flue gas wet desulfurization, etc.). The filter residue was washed and dried to obtain a desilicated stone coal (denoted as C2), and the filtrate was a sodium silicate solution.

[0045] Example 3

[0046] (1) Raw material mixing and grinding: 100 g of dry-based stone coal and 2 g of dry-based magnesium-aluminum hydrotalcite were weighed and mixed, and then ground to obtain a mixed powder.

[0047] (2) High-temperature calcination and activation: the mixed powder obtained in step (1) was placed in a calcination device and calcined at 950°C for 110 min, and then cooled to obtain a calcined stone coal.

[0048] (3) Alkali solution reaction: 50 g of the calcined stone coal obtained in step (2), 25 g of sodium hydroxide and 300 g of water were weighed and added into a reaction container, and stirred at 88°C for 2 h. After the reaction, the reaction system was filtered to obtain a filter residue and a filtrate (main component: sodium silicate, which can be used for subsequent resource utilization such as zeolite molecular sieve / silica synthesis, flue gas wet desulfurization, etc.). The filter residue was washed and dried to obtain a desilicated stone coal (denoted as C3), and the filtrate was a sodium silicate solution.

[0049] Example 4

[0050] (1) Raw material mixing and grinding: 100 g of dry-based stone coal and 2.5 g of dry-based magnesium-aluminum hydrotalcite were weighed and mixed, and then ground to obtain a mixed powder.

[0051] (2) High-temperature calcination and activation: the mixed powder obtained in step (1) was placed in a calcination device and calcined at 1000°C for 70 min, and then cooled to obtain a calcined stone coal.

[0052] (3) Alkali solution reaction: 50 g of the calcined stone coal obtained in step (2), 35 g of sodium hydroxide and 350 g of water were weighed and added into a reaction container, and stirred at 92°C for 1.5 h. After the reaction, the reaction system was filtered to obtain a filter residue and a filtrate (main component: sodium silicate, which can be used for subsequent resource utilization such as zeolite molecular sieve / silica synthesis, flue gas wet desulfurization, etc.). The filter residue was washed and dried to obtain a desilicated stone coal (denoted as C4), and the filtrate was a sodium silicate solution.

[0053] Example 5

[0054] (1) Raw material mixing and grinding: 100 g of dry-based stone coal and 3 g of dry-based magnesium-aluminum hydrotalcite were mixed and ground to obtain a mixed powder.

[0055] (2) High-temperature calcination and activation: the mixed powder obtained in step (1) was placed in a calcination device and calcined at a temperature of 1050°C for 30 min, and then cooled to obtain calcined stone coal.

[0056] (3) Alkaline solution reaction: 50 g of calcined stone coal obtained in step (2), 50 g of sodium hydroxide, and 400 g of water were added to a reaction container, and stirred at a constant temperature of 95°C for 1 h; after the reaction was completed, the reaction system was filtered and separated to obtain a filter residue and a filtrate (main component: sodium silicate, which can be used for subsequent resource utilization such as zeolite molecular sieve / white carbon black synthesis, flue gas wet desulfurization, etc.); the filter residue was sequentially washed and dried to obtain desilicated stone coal (denoted as C5).

[0057] Comparative Example 1

[0058] (1) Raw material mixing and grinding: 100 g of dry-based stone coal was calcined at a temperature of 850°C for 180 min, and then cooled to obtain calcined stone coal.

[0059] (2) Alkaline solution reaction: 50 g of calcined stone coal obtained in step (1), 5 g of sodium hydroxide, and 200 g of water were added to a reaction container, and stirred at a constant temperature of 80°C for 3 h; after the reaction was completed, the reaction system was filtered and separated to obtain a filter residue and a filtrate; the filter residue was sequentially washed and dried to obtain desilicated stone coal (denoted as D1).

[0060] Comparative Example 2

[0061] (1) Raw material mixing and grinding: 100 g of dry-based stone coal was calcined at a temperature of 950°C for 110 min, and then cooled to obtain calcined stone coal.

[0062] (2) Alkaline solution reaction: 50 g of calcined stone coal obtained in step (1), 25 g of sodium hydroxide, and 300 g of water were added to a reaction container, and stirred at a constant temperature of 88°C for 2 h; after the reaction was completed, the reaction system was filtered and separated to obtain a filter residue and a filtrate; the filter residue was sequentially washed and dried to obtain desilicated stone coal (denoted as D2).

[0063] Comparative Example 3

[0064] (1) Raw material mixing and grinding: 100 g of dry-based stone coal was calcined at a temperature of 1050°C for 30 min, and then cooled to obtain calcined stone 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 (C4) 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. A method for desiliconizing and vanadium extraction from solid waste stone coal based on the structure memory effect of hydrotalcite, characterized in that, The method comprises the following steps: (1) mixing and roasting stone coal and a vanadium capturing agent to obtain roasted stone coal; (2) mixing the roasted stone coal and an inorganic alkali in water, and reacting the mixed system at 80-95 DEG C, filtering, washing and drying to obtain desilicated stone coal; The vanadium capturing agent is hydrotalcite; the hydrotalcite is at least one of magnesium-aluminum hydrotalcite, calcium-aluminum hydrotalcite and zinc-aluminum hydrotalcite; The crystallinity of the hydrotalcite is greater than or equal to 85%; The mass ratio of the stone coal and the vanadium capturing agent is 1:(0.01-0.03) on a dry basis; The temperature of the mixing and roasting is 800-1100 DEG C, and the time is 30-180 min; The inorganic alkali is at least one of sodium hydroxide, potassium hydroxide, sodium carbonate and potassium carbonate; The mass ratio of the roasted stone coal, the inorganic alkali and water is 1:(0.1-1):(4-8).

Images