Method for extracting rare earth elements from gasification furnace slag and preparing foam microcrystalline glass through cooperation of rare earth elements and fly ash

Abstract

The invention relates to the technical field of hazardous waste treatment, in particular to a method for extracting rare earth elements from gasification furnace slag and preparing foam microcrystalline glass from the gasification furnace slag and fly ash. The method comprises the following steps: mixing the gasification furnace slag with small molecular organic acid, uniformly stirring, and controlling the pH value to be 3-5; filtering, and respectively collecting solid residues and leachate; adding oxalate into the leachate in batches to separate rare earth elements, and filtering to obtain the rare earth elements and waste liquid; the method comprises the following steps: mixing organic incineration fly ash and solid residues, grinding, heating in a corundum crucible, and preserving heat to obtain a basic glass melt; carrying out water quenching or room temperature cooling on the basic glass melt to obtain glass slag, and drying to constant weight; glass slag is added into the waste liquid, a certain amount of calcium carbonate is added for mixing, injection molding and curing are conducted, and then demolding is conducted to obtain a foaming blank; and drying and sintering the foamed blank to obtain the foam microcrystalline glass. According to the method, hazardous waste materials are completely utilized, the preparation process is simple, and the waste utilization rate is high.

Description

Technical Field

[0001] The present invention relates to the technical field of hazardous waste treatment, and in particular to a method for extracting rare earth elements from gasified slag and preparing foamed microcrystalline glass from gasified slag and fly ash. Background Art

[0002] my country is currently the world's largest coal producer and consumer. The resource characteristics of rich coal, poor oil and little gas determine that coal occupies a dominant position in the process of my country's national economic and social development. According to the 2017 BP World Energy Statistical Yearbook, China's coal production and consumption accounted for 46.1% and 50.6% of the global coal production and consumption respectively in 2016. According to the BP 2035 World Energy Outlook, by 2035, China will account for 51% of the world's coal consumption and will still be the world's largest coal consumer; it can be foreseen that coal will continue to dominate China's primary energy for a considerable period of time in the future. With the development of the coal gasification industry, the installed capacity of coal gasifiers has increased significantly, and the generation of gasification slag in the coal gasification process is inevitable. At present, the annual output of gasification slag in the country has reached several million tons, and this number will continue to increase. Such a huge output of gasification slag has brought great pressure to environmental protection. Therefore, how to make secondary use of it is a major problem that needs to be dealt with urgently. As my country's economic development continues to improve, people's living material basis and urbanization rate continue to improve, and the proper management of solid waste is usually accompanied by a very high cost. According to statistics, the global average cost of treating each ton of solid waste is about US$205.4, and it is expected to increase fivefold by 2025-2030. Sinopec has established regional hazardous waste disposal centers and self-built hazardous waste treatment equipment, totaling 12 sets. After the incineration / pyrolysis treatment of hazardous waste, the ash is still hazardous waste, and the cost of outsourcing is high and there are legal risks.

[0003] The role of rare earth elements in modern industry is increasing day by day. With the growing demand in the future and the gradual consumption of traditional deposits, finding new sources of rare earth resources has become the focus of global attention. It is worth noting that the extraction of rare earth elements from gasification slag has been an important research direction for the high value-added utilization of coal-based solid waste in recent years. Gasification slag is therefore regarded as an alternative source of rare earth elements. In particular, the United States is committed to establishing a complete supply chain of rare earth resources in China and is investing huge energy in the industrialization of rare earth element extraction from fly ash. Although China is a country with a large number of rare earth resources, with the increasing consumption of traditional rare earth deposits, how to continue to ensure the strategic advantage of rare earth resources has become an urgent problem that China needs to solve. Therefore, the method and research of extracting and utilizing rare earth elements from coal-based solid waste has important scientific value, economic benefits and social effects. It is not only an effective way to reduce the environmental pollution of fly ash and gasification slag, but also a new idea for achieving efficient recycling. At the same time, as a potential source of rare earth element extraction in China, it is one of the important choices for China to ensure its strategic advantage in rare earth resources in response to the Sino-US trade dispute.

[0004] Foam glass-ceramics has great application prospects in the fields of building materials, filtration materials, seawater desalination, catalyst carriers, biological implant materials and high-temperature insulation materials. Slag foam glass-ceramics (using industrial and mining waste slag as raw materials). At present, the raw materials for preparing foam glass-ceramics are mainly industrial waste slag, such as blast furnace slag, fly ash, waste glass, coal gangue and metal tailings.

[0005] In the prior art, patent CN113087398A (a glass-ceramic prepared from coal gasification slag and a preparation method thereof) discloses a glass-ceramic prepared from coal gasification slag and a preparation method thereof. Although it has opened up a sustainable development path for coal chemical industry, the method has too high melting temperature and too long insulation time, and does not fully utilize the metal elements in gasification slag and slag. Patent CN108149033A (a process for extracting rare earth elements from fly ash) uses a large amount of hydrochloric acid, and does not fully utilize the residue after the leaching liquid, and does not achieve 100% utilization of solid waste. Patent CN115028367A (a method for preparing foam glass-ceramic from secondary aluminum ash slag) discloses a method for preparing foam glass-ceramic from secondary aluminum ash slag. This method does not achieve 100% utilization of hazardous waste, and uses surface modifiers such as sodium dodecyl sulfate and hexadecyltrimethylammonium bromide, resulting in increased costs and environmental pollution.

[0006] The use of gasification ash and other industrial hazardous wastes to prepare foamed microcrystalline glass can not only realize the resource recycling of industrial solid waste and protect the environment, but also improve economic benefits and promote the green and sustainable development of the waste incineration industry. By extracting rare earth elements from gasification slag for comprehensive utilization, and using the residue to prepare foamed microcrystalline glass in conjunction with hazardous waste, the utilization rate and added value of gasification slag ash can be improved, while reducing the impact of solid waste and hazardous waste on the environment, and realizing the green and efficient recycling of secondary resources of solid waste. However, there are few methods in the prior art that use gasification slag to extract rare earth elements and prepare foamed microcrystalline glass in conjunction with fly ash. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a method for extracting rare earth elements from gasification slag and preparing foam microcrystalline glass from gasification slag and fly ash.

[0008] The technical solutions adopted are:

[0009] A method for extracting rare earth elements from gasified slag and preparing foamed glass-ceramics from gasified slag and fly ash, comprising the following steps:

[0010] (1) mixing the gasification slag with a small molecular organic acid, stirring continuously and uniformly, and controlling the pH value to 3 to 5 by using a buffer solution;

[0011] (2) filtering the solid-liquid mixture prepared in step (1) to collect solid residue and leachate respectively;

[0012] (3) adding oxalate to the leachate in batches to separate the rare earth elements, so as to separate the rare earth elements from other metals; filtering to obtain the rare earth elements and waste liquid;

[0013] (4) mixing the fly ash from the organic incineration and the solid residue filtered in step (2), and grinding them to 200 mesh; placing the ground mixture in a corundum crucible and heating it to 1100-1300° C., and keeping it warm for a certain period of time to obtain a basic glass melt;

[0014] (5) quenching the basic glass melt with water or cooling it at room temperature to obtain glass slag, and drying the glass slag to a constant weight;

[0015] (6) adding the dried glass slag to the waste liquid in step (3), and adding a certain amount of calcium carbonate to mix, to obtain a uniformly mixed slurry, injection molding and curing, and then demolding to obtain a foamed blank;

[0016] (7) The foamed blank is placed in a drying oven for drying, and then sintered to obtain foamed glass-ceramics.

[0017] Among them, the fly ash from organic incineration can be fly ash and bottom ash from the incineration of organic hazardous waste, which refers to the fly ash and bottom ash produced by incineration (or pyrolysis) of one or more of the typical petrochemical refining hazardous wastes (hydrocarbon polymers from cracking filters, waste solvent oil, coke residue from cracking heat exchangers, waste fusel alcohols, etc.), chemical hazardous wastes (organic solvents), and sewage treatment devices (residual activated sludge, oily sludge).

[0018] Hazardous characteristics of fly ash and bottom slag from incineration of organic hazardous waste: lead content <20mg / kg, mercury content <5mg / kg, arsenic content <50mg / kg, selenium content <30mg / kg, antimony content <10mg / kg, titanium content <800mg / kg, manganese content <500mg / kg, cobalt content <50mg / kg, barium content <800mg / kg, vanadium content <4000mg / kg, copper content <100mg / kg, zinc content <2500mg / kg, chromium content <4000mg / kg, nickel content <500mg / kg, cadmium content <5mg / kg, inorganic fluorine content <500mg / kg, cyanide content <5mg / kg, and the pH of the leaching solution is 10-13.

[0019] As a further preference, the sum of the mass fractions of SiO2, Al2O3 and Fe2O3 in the gasification slag is greater than 70wt%, and the mass fraction of residual carbon is less than 10wt%. The main components of the gasification slag include, by mass percentage, 23-46% SiO2, 8-15% Al2O3, 0.9-3% Na2O, 0.1-2.0% K2O, 6.1-24.0% CaO, 0.5-1.0% MgO, 5.6-12.6% Fe2O3 and 0.1-0.6% TiO2.

[0020] As a further preference, in the step (1), the small molecule organic acid is a mixture of citric acid and malic acid, and the liquid-solid ratio is 100-200 mL / g; the buffer solution is a dilute hydrochloric acid (HCl) solution, and the pH of the solution is controlled to be 4.

[0021] As a further preference, the proportions of citric acid and malic acid added are: citric acid: 50% to 70%, malic acid: 30% to 50% respectively.

[0022] As a further preference, in the step (2), the filter membrane used for filtration is 0.220 μm.

[0023] As a further preference, in the step (3), 0.0015-0.0025% oxalate is added to the leachate in batches, and the oxalate is any one of calcium oxalate and sodium oxalate.

[0024] As a further preference, the mass ratio of organic incineration fly ash to solid residue is 1:2-5, and more preferably, the ratio is 1:4. The organic incineration fly ash may also be organic hazardous waste incineration fly ash or bottom slag.

[0025] When preparing foamed microcrystalline glass, waste glass and glass powder can be added to the fly ash, bottom slag and solid residue of organic incineration, and the sources are medical waste glass, waste glass products for daily use and waste glass for architectural decoration. Based on the total weight of the mixture, the fly ash and bottom slag of heavy alcohol incineration are 10-20wt%, the waste glass is 0-20wt%, the gasification slag is 60-90wt%, and the co-solvent is B2O3, which accounts for 5-15wt%.

[0026] As a further preference, in the step (4), the heating rate of the corundum crucible is 5 to 20° C. / min, and the holding time is 30 to 120 min.

[0027] As a further preference, in the step (5), the drying temperature is 100-110°C.

[0028] As a further preference, in step (6), the waste liquid contains residual oxalate and oxalic acid, 3% calcium carbonate is added, and the generated calcium oxalate is used as a foaming agent.

[0029] As a further preferred embodiment, in the step (6), the sintering temperature is 950-1200° C., and the sintering time is 30-120 min.

[0030] Compared with the prior art, the present invention has the following remarkable effects:

[0031] The present invention uses a method for extracting and utilizing rare earth elements from gasification furnace slag and simultaneously uses fly ash to prepare foamed microcrystalline glass, thereby fully utilizing hazardous waste materials.

[0032] The method of extracting rare earth elements from gasification slag and preparing foamed microcrystalline glass from gasification slag and fly ash of the present invention is beneficial to solidifying harmful heavy metal ions in petrochemical organic incineration fly ash, thereby improving the comprehensive solidification efficiency.

[0033] The method of extracting rare earth elements from gasified slag and preparing foamed microcrystalline glass from gasified slag and fly ash of the present invention has a simple preparation process, does not need to add other residual substances, and has a high waste utilization rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of the process of the present invention;

[0035] Figure 2 This is a microscope image of the foam microcrystalline glass prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0036] The drawings are only used for illustrative purposes; for those skilled in the art, some well-known structures and their descriptions in the drawings may be omitted, and therefore, they should not be understood as limitations on the present invention.

[0037] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further described in detail below in conjunction with embodiments and drawings.

[0038] Example 1

[0039] A method for extracting rare earth elements from gasified slag and preparing foamed glass-ceramics from gasified slag and fly ash, which is specifically prepared by the following steps:

[0040] (1) The gasification slag sample was mixed with citric acid (120 mM) and malic acid (80 mM) at room temperature under continuous stirring (200 rpm) with a liquid-to-solid ratio of 200 mL / g and the pH was controlled to 4 by dilute hydrochloric acid.

[0041] (2) After leaching, the solid residue and the leachate were separated by filtration through a 0.22 μm filter membrane.

[0042] (3) Add 0.0015% oxalate to the leachate in batches to separate the rare earth elements from other metals. Add sodium oxalate three times, 50 mL each time.

[0043] (4) mixing the organic incineration ash (fly ash and bottom slag) and the solid residue filtered out in step (1) in a ratio of 2:8, and grinding the mixture to 200 mesh; placing the ground mixture in a corundum crucible and heating it to 1300° C. at a heating rate of 10° C. / min, and keeping the temperature for 120 min to obtain a basic glass melt.

[0044] (5) The base glass melt is water quenched (or cooled at room temperature) to obtain glass slag, and the glass slag is dried at 105° C. to constant weight.

[0045] (6) Add the dried glass slag to the waste liquid in step (3), and add 3% calcium carbonate to mix to obtain a uniformly mixed slurry, inject and cure it for 120 minutes, and then demold it to obtain a foamed blank.

[0046] (7) The foamed blank is placed in a drying oven to dry, and then sintered at 1050° C. to obtain foamed glass-ceramics.

[0047] The total rare earth element leaching efficiency of the gasification slag in this embodiment is 68.3%. The physical and chemical properties of the glass ceramic product prepared in this embodiment include: the density of the foam microcrystalline material prepared from the solid residue filtered from the gasification slag is 0.93g / cm 3The obtained foam microcrystalline glass has a porosity of 67.25%, a compressive strength of 12.1 MPa, an acid resistance of 1.19wt%, and an alkali resistance of 1.35wt%.

[0048] like Figure 1 As shown, the foam microcrystalline glass prepared in this embodiment. It can be seen from the figure that the foam microcrystalline glass prepared by the raw materials and steps of this method has uniform texture and good quality.

[0049] In order to further optimize the technical parameters of the method of the present invention, the preferred schemes of various parameters are further determined through Examples 2-15 below.

[0050] Example 2

[0051] A method for extracting rare earth elements from gasified slag and preparing foamed glass-ceramics from gasified slag and fly ash, which is specifically prepared by the following steps:

[0052] (1) At room temperature, the gasification slag sample was mixed with citric acid (120 mM) and malic acid (80 mM) under continuous stirring (200 rpm) at a liquid-to-solid ratio of 200 mL / g, and the pH was controlled to 3 by dilute hydrochloric acid.

[0053] (2) After leaching, the solid residue and the leachate were separated by filtration through a 0.22 μm filter membrane.

[0054] (3) Add 0.0015% oxalate to the leachate in batches to separate the rare earth elements from other metals. Add sodium oxalate three times, 50 mL each time.

[0055] (4) mixing the organic incineration ash (fly ash and bottom slag) and the solid residue filtered out in step (1) in a ratio of 2:8, and grinding the mixture to 200 mesh; placing the ground mixture in a corundum crucible and heating it to 1300° C. at a heating rate of 10° C. / min, and keeping the temperature for 120 min to obtain a basic glass melt.

[0056] (5) The base glass melt is water quenched (or cooled at room temperature) to obtain glass slag, and the glass slag is dried at 105° C. to constant weight.

[0057] (6) Add the dried glass slag to the waste liquid in step (3), and add 3% calcium carbonate to mix to obtain a uniformly mixed slurry, inject and cure it for 120 minutes, and then demold it to obtain a foamed blank.

[0058] (7) The foamed blank is placed in a drying oven to dry, and then sintered at 1050° C. to obtain foamed glass-ceramics.

[0059] The efficiency and properties of the obtained products are compared in Table 1.

[0060] Example 3

[0061] A method for extracting rare earth elements from gasified slag and preparing foamed glass-ceramics from gasified slag and fly ash, which is specifically prepared by the following steps:

[0062] (1) At room temperature, the gasification slag sample was mixed with citric acid (120 mM) and malic acid (80 mM) under continuous stirring (200 rpm) at a liquid-to-solid ratio of 200 mL / g, and the pH was controlled to 5 by dilute hydrochloric acid.

[0063] (2) After leaching, the solid residue and the leachate were separated by filtration through a 0.22 μm filter membrane.

[0064] (3) Add 0.0015% oxalate to the leachate in batches to separate the rare earth elements from other metals. Add sodium oxalate three times, 50 mL each time.

[0065] (4) mixing the organic incineration ash (fly ash and bottom slag) and the solid residue filtered out in step (1) in a ratio of 2:8, and grinding the mixture to 200 mesh; placing the ground mixture in a corundum crucible and heating it to 1300° C. at a heating rate of 10° C. / min, and keeping the temperature for 120 min to obtain a basic glass melt.

[0066] (5) The base glass melt is water quenched (or cooled at room temperature) to obtain glass slag, and the glass slag is dried at 105° C. to constant weight.

[0067] (6) Add the dried glass slag to the waste liquid in step (3), and add 3% calcium carbonate to mix to obtain a uniformly mixed slurry, inject and cure it for 120 minutes, and then demold it to obtain a foamed blank.

[0068] (7) The foamed blank is placed in a drying oven to dry, and then sintered at 1050° C. to obtain foamed glass-ceramics.

[0069] The efficiency and properties of the obtained products are compared in Table 1.

[0070] The rare earth element leaching efficiency of the solid-liquid mixture at different pH values ​​in step (1) of Examples 1, 2, and 3 and the properties of the prepared microcrystalline glass are compared, see Table 1.

[0071] Table 1 is a comparison of rare earth element leaching efficiency and foamed microcrystalline glass performance of Examples 1-3

[0072]

[0073] It can be seen from Table 1 that different pH values ​​of the solid-liquid mixture in step (1) have a relatively large influence on the leaching efficiency of rare earth elements, and the leaching efficiency of rare earth elements is best when the pH value is 4. Different pH values ​​have little influence on the density, porosity and compressive strength of foamed microcrystalline glass.

[0074] Example 4

[0075] A method for extracting rare earth elements from gasified slag and preparing foamed glass-ceramics from gasified slag and fly ash, which is specifically prepared by the following steps:

[0076] (1) The gasification slag sample was mixed with citric acid (100 mM) and malic acid (100 mM) at room temperature under continuous stirring (200 rpm) with a liquid-to-solid ratio of 200 mL / g and the pH was controlled to 4 by dilute hydrochloric acid.

[0077] (2) After leaching, the solid residue and the leachate were separated by filtration through a 0.22 μm filter membrane.

[0078] (3) Add 0.0015% oxalate to the leachate in batches to separate the rare earth elements from other metals. Add sodium oxalate three times, 50 mL each time.

[0079] (4) mixing the organic incineration ash (fly ash and bottom slag) and the solid residue filtered out in step (1) in a ratio of 2:8, and grinding the mixture to 200 mesh; placing the ground mixture in a corundum crucible and heating it to 1300° C. at a heating rate of 10° C. / min, and keeping the temperature for 120 min to obtain a basic glass melt.

[0080] (5) The base glass melt is water quenched (or cooled at room temperature) to obtain glass slag, and the glass slag is dried at 105° C. to constant weight.

[0081] (6) Add the dried glass slag to the waste liquid in step (3), and add 3% calcium carbonate to mix to obtain a uniformly mixed slurry, inject and cure it for 120 minutes, and then demold it to obtain a foamed blank.

[0082] (7) The foamed blank is placed in a drying oven to dry, and then sintered at 1050° C. to obtain foamed glass-ceramics.

[0083] The efficiency and properties of the obtained products are compared in Table 2.

[0084] Example 5

[0085] A method for extracting rare earth elements from gasified slag and preparing foamed glass-ceramics from gasified slag and fly ash, which is specifically prepared by the following steps:

[0086] (1) At room temperature, the gasification slag sample was mixed with citric acid (140 mM) and malic acid (60 mM) under continuous stirring (200 rpm) at a liquid-to-solid ratio of 200 mL / g, and the pH was controlled to 4 by dilute hydrochloric acid.

[0087] (2) After leaching, the solid residue and the leachate were separated by filtration through a 0.22 μm filter membrane.

[0088] (3) Add 0.0015% oxalate to the leachate in batches to separate the rare earth elements from other metals. Add sodium oxalate three times, 50 mL each time.

[0089] (4) mixing the organic incineration ash (fly ash and bottom slag) and the solid residue filtered out in step (1) in a ratio of 2:8, and grinding the mixture to 200 mesh; placing the ground mixture in a corundum crucible and heating it to 1300° C. at a heating rate of 10° C. / min, and keeping the temperature for 120 min to obtain a basic glass melt.

[0090] (5) The base glass melt is water quenched (or cooled at room temperature) to obtain glass slag, and the glass slag is dried at 105° C. to constant weight.

[0091] (6) Add the dried glass slag to the waste liquid in step (3), and add 3% calcium carbonate to mix to obtain a uniformly mixed slurry, inject and cure it for 120 minutes, and then demold it to obtain a foamed blank.

[0092] (7) The foamed blank is placed in a drying oven to dry, and then sintered at 1050° C. to obtain foamed glass-ceramics.

[0093] The efficiency and properties of the obtained products are compared in Table 2.

[0094] The effects of different proportions of organic acid in the solid-liquid mixture in step (1) of Examples 1, 4 and 5 on the leaching efficiency of rare earth elements and the properties of the prepared microcrystalline glass are compared, see Table 2.

[0095] Table 2 is a comparison of rare earth element leaching efficiency and foamed microcrystalline glass performance of Examples 1, 4, and 5

[0096]

[0097] It can be seen from Table 1 that different proportions of organic acid have a greater effect on the leaching efficiency of rare earth elements, and the effect on foamed microcrystalline glass is negligible.

[0098] Example 6

[0099] A method for extracting rare earth elements from gasified slag and preparing foamed glass-ceramics from gasified slag and fly ash, which is specifically prepared by the following steps:

[0100] (1) The gasification slag sample was mixed with citric acid (120 mM) and malic acid (80 mM) at room temperature under continuous stirring (200 rpm) with a liquid-to-solid ratio of 200 mL / g and the pH was controlled to 4 by dilute hydrochloric acid.

[0101] (2) After leaching, the solid residue and the leachate were separated by filtration through a 0.22 μm filter membrane.

[0102] (3) Add 0.0015% oxalate to the leachate in batches to separate the rare earth elements from other metals. Add sodium oxalate three times, 50 mL each time.

[0103] (4) mixing the organic incineration ash (fly ash and bottom slag) and the solid residue filtered out in step (1) in a ratio of 2:8, and grinding the mixture to 200 mesh; placing the ground mixture in a corundum crucible and heating it to 1300° C. at a heating rate of 10° C. / min, and keeping the temperature for 120 min to obtain a basic glass melt.

[0104] (5) The base glass melt is water quenched (or cooled at room temperature) to obtain glass slag, and the glass slag is dried at 105° C. to constant weight.

[0105] (6) Add the dried glass slag to the waste liquid in step (3), and add 3% calcium carbonate to mix to obtain a uniformly mixed slurry, inject and cure it for 120 minutes, and then demold it to obtain a foamed blank.

[0106] (7) The foamed blank is placed in a drying oven to dry, and then sintered at 950° C. to obtain foamed glass-ceramics.

[0107] The efficiency and properties of the obtained products are compared in Table 3.

[0108] Example 7

[0109] A method for extracting rare earth elements from gasified slag and preparing foamed glass-ceramics from gasified slag and fly ash, which is specifically prepared by the following steps:

[0110] (1) The gasification slag sample was mixed with citric acid (120 mM) and malic acid (80 mM) at room temperature under continuous stirring (200 rpm) with a liquid-to-solid ratio of 200 mL / g and the pH was controlled to 4 by dilute hydrochloric acid.

[0111] (2) After leaching, the solid residue and the leachate were separated by filtration through a 0.22 μm filter membrane.

[0112] (3) Add 0.0015% oxalate to the leachate in batches to separate the rare earth elements from other metals. Add sodium oxalate three times, 50 mL each time.

[0113] (4) mixing the organic incineration ash (fly ash and bottom slag) and the solid residue filtered out in step (1) in a ratio of 2:8, and grinding the mixture to 200 mesh; placing the ground mixture in a corundum crucible and heating it to 1300° C. at a heating rate of 10° C. / min, and keeping the temperature for 120 min to obtain a basic glass melt.

[0114] (5) The base glass melt is water quenched (or cooled at room temperature) to obtain glass slag, and the glass slag is dried at 105° C. to constant weight.

[0115] (6) Add the dried glass slag to the waste liquid in step (3), and add 3% calcium carbonate to mix to obtain a uniformly mixed slurry, inject and cure it for 120 minutes, and then demold it to obtain a foamed blank.

[0116] (7) The foamed blank is placed in a drying oven to dry, and then sintered at 1000° C. to obtain foamed glass-ceramics.

[0117] The efficiency and properties of the obtained products are compared in Table 3.

[0118] Example 8

[0119] A method for extracting rare earth elements from gasified slag and preparing foamed glass-ceramics from gasified slag and fly ash, which is specifically prepared by the following steps:

[0120] (1) At room temperature, the gasification slag sample was mixed with citric acid (120 mM) and malic acid (80 mM) under continuous stirring (200 rpm) at a liquid-to-solid ratio of 220 mL / g, and the pH was controlled to 4 by dilute hydrochloric acid.

[0121] (2) After leaching, the solid residue and the leachate were separated by filtration through a 0.22 μm filter membrane.

[0122] (3) Add 0.0015% oxalate to the leachate in batches to separate the rare earth elements from other metals. Add sodium oxalate three times, 50 mL each time.

[0123] (4) mixing the organic incineration ash (fly ash and bottom slag) and the solid residue filtered out in step (1) in a ratio of 2:8, and grinding the mixture to 200 mesh; placing the ground mixture in a corundum crucible and heating it to 1300° C. at a heating rate of 10° C. / min, and keeping the temperature for 120 min to obtain a basic glass melt.

[0124] (5) The base glass melt is water quenched (or cooled at room temperature) to obtain glass slag, and the glass slag is dried at 105° C. to constant weight.

[0125] (6) Add the dried glass slag to the waste liquid in step (3), and add 3% calcium carbonate to mix to obtain a uniformly mixed slurry, inject and cure it for 120 minutes, and then demold it to obtain a foamed blank.

[0126] (7) The foamed blank is placed in a drying oven to dry, and then sintered at 1200° C. to obtain foamed glass-ceramics.

[0127] The efficiency and properties of the obtained products are compared in Table 3.

[0128] The dried foamed blanks in Examples 1 and 6-8 were sintered, and the properties of the microcrystalline glasses prepared at different sintering temperatures were compared, as shown in Table 3.

[0129] Table 3 is a comparison of the properties of foamed glass-ceramics of Examples 1, 6-8

[0130]

[0131] It can be seen from Table 3 that among the glass-ceramics prepared at different sintering temperatures, the foamed glass-ceramics sintered at 1050°C has the best performance.

[0132] Example 9

[0133] A method for extracting rare earth elements from gasified slag and preparing foamed glass-ceramics from gasified slag and fly ash, which is specifically prepared by the following steps:

[0134] (1) The gasification slag sample was mixed with citric acid (120 mM) and malic acid (80 mM) at room temperature under continuous stirring (200 rpm) with a liquid-to-solid ratio of 200 mL / g and the pH was controlled to 4 by dilute hydrochloric acid.

[0135] (2) After leaching, the solid residue and the leachate were separated by filtration through a 0.22 μm filter membrane.

[0136] (3) Add 0.0015% oxalate to the leachate in batches to separate the rare earth elements from other metals. Add sodium oxalate three times, 50 mL each time.

[0137] (4) mixing the organic incineration ash (fly ash and bottom slag) and the solid residue filtered out in step (1) in a ratio of 4:8, and grinding the mixture to 200 mesh; placing the ground mixture in a corundum crucible and heating it to 1300° C. at a heating rate of 10° C. / min, and keeping the temperature for 120 min to obtain a basic glass melt.

[0138] (5) The base glass melt is water quenched (or cooled at room temperature) to obtain glass slag, and the glass slag is dried at 105° C. to constant weight.

[0139] (6) Add the dried glass slag to the waste liquid in step (3), and add 2% calcium carbonate to mix to obtain a uniformly mixed slurry, inject and cure it for 120 minutes, and then demold it to obtain a foamed blank.

[0140] (7) The foamed blank is placed in a drying oven to dry, and then sintered at 1050° C. to obtain foamed glass-ceramics.

[0141] The efficiency and properties of the obtained products are compared in Table 4.

[0142] Example 10

[0143] A method for extracting rare earth elements from gasified slag and preparing foamed glass-ceramics from gasified slag and fly ash, which is specifically prepared by the following steps:

[0144] (1) At room temperature, the gasification slag sample was mixed with citric acid (120 mM) and malic acid (80 mM) under continuous stirring (200 rpm) at a liquid-to-solid ratio of 200 mL / g, and the pH was controlled to 4 by dilute hydrochloric acid.

[0145] (2) After leaching, the solid residue and the leachate were separated by filtration through a 0.22 μm filter membrane.

[0146] (3) Add 0.0015% oxalate to the leachate in batches to separate the rare earth elements from other metals. Add sodium oxalate three times, 50 mL each time.

[0147] (4) mixing the organic incineration ash (fly ash and bottom slag) and the solid residue filtered out in step (1) in a ratio of 2:8, and grinding the mixture to 200 mesh; placing the ground mixture in a corundum crucible and heating it to 1300° C. at a heating rate of 10° C. / min, and keeping the temperature for 120 min to obtain a basic glass melt.

[0148] (5) The base glass melt is water quenched (or cooled at room temperature) to obtain glass slag, and the glass slag is dried at 105° C. to constant weight.

[0149] (6) Add the dried glass slag to the waste liquid in step (3), and add 4% calcium carbonate to mix to obtain a uniformly mixed slurry, inject and cure it for 120 minutes, and then demold it to obtain a foamed blank.

[0150] (7) The foamed blank is placed in a drying oven to dry, and then sintered at 1050° C. to obtain foamed glass-ceramics.

[0151] The efficiency and properties of the obtained products are compared in Table 4.

[0152] Embodiment 11

[0153] A method for extracting rare earth elements from gasified slag and preparing foamed glass-ceramics from gasified slag and fly ash, which is specifically prepared by the following steps:

[0154] (1) At room temperature, the gasification slag sample was mixed with citric acid (120 mM) and malic acid (80 mM) under continuous stirring (200 rpm) at a liquid-to-solid ratio of 200 mL / g, and the pH was controlled to 4 by dilute hydrochloric acid.

[0155] (2) After leaching, the solid residue and the leachate were separated by filtration through a 0.22 μm filter membrane.

[0156] (3) Add 0.0015% oxalate to the leachate in batches to separate the rare earth elements from other metals. Add sodium oxalate three times, 50 mL each time.

[0157] (4) mixing the organic incineration ash (fly ash and bottom slag) and the solid residue filtered out in step (1) in a ratio of 1:5, and grinding the mixture to 200 mesh; placing the ground mixture in a corundum crucible and heating it to 1300° C. at a heating rate of 10° C. / min, and keeping the temperature for 120 min to obtain a basic glass melt.

[0158] (5) The base glass melt is water quenched (or cooled at room temperature) to obtain glass slag, and the glass slag is dried at 105° C. to constant weight.

[0159] (6) Add the dried glass slag to the waste liquid in step (3), and add 5% calcium carbonate to mix to obtain a uniformly mixed slurry, inject and cure it for 120 minutes, and then demold it to obtain a foamed blank.

[0160] (7) The foamed blank is placed in a drying oven to dry, and then sintered at 1050° C. to obtain foamed glass-ceramics.

[0161] The efficiency and properties of the obtained products are compared in Table 4.

[0162] The properties of the glass-ceramics prepared with different fractions of oxalate in Examples 1 and 9-11 were compared, and the results are shown in Table 4.

[0163] Table 4 is a comparison of the properties of foamed glass-ceramics prepared in Examples 1, 9-11

[0164]

[0165] It can be seen from Table 4 that in step (3), different mass fractions of calcium carbonate are added to the leachate. Excessive calcium carbonate causes the voids of the microcrystalline glass to be uneven and too large, resulting in a decrease in the performance of the foam microcrystalline glass.

[0166] Example 12

[0167] A method for extracting rare earth elements from gasified slag and preparing foamed glass-ceramics from gasified slag and fly ash, which is specifically prepared by the following steps:

[0168] (1) At room temperature, the gasification slag sample was mixed with citric acid (120 mM) and malic acid (80 mM) under continuous stirring (200 rpm) at a liquid-to-solid ratio of 200 mL / g, and the pH was controlled to 4 by dilute hydrochloric acid.

[0169] (2) After leaching, the solid residue and the leachate were separated by filtration through a 0.22 μm filter membrane.

[0170] (3) Add 0.0015% oxalate to the leachate in batches to separate the rare earth elements from other metals. Add sodium oxalate three times, 50 mL each time.

[0171] (4) Mixing organic incineration ash (fly ash and bottom slag) and the solid residue filtered out in step (1) in a ratio of 1:2, and grinding to 200 mesh; placing the ground mixture in a corundum crucible and heating it to 1300° C. at a heating rate of 10° C. / min, and keeping the temperature for 120 min to obtain a basic melt, and cooling it to find that no glass can be formed.

[0172] Embodiment 13

[0173] A method for extracting rare earth elements from gasified slag and preparing foamed glass-ceramics from gasified slag and fly ash, which is specifically prepared by the following steps:

[0174] (1) At room temperature, the gasification slag sample was mixed with citric acid (120 mM) and malic acid (80 mM) under continuous stirring (200 rpm) at a liquid-to-solid ratio of 200 mL / g, and the pH was controlled to 4 by dilute hydrochloric acid.

[0175] (2) After leaching, the solid residue and the leachate were separated by filtration through a 0.22 μm filter membrane.

[0176] (3) Add 0.0015% oxalate to the leachate in batches to separate the rare earth elements from other metals. Add sodium oxalate three times, 50 mL each time.

[0177] (4) mixing the organic incineration ash (fly ash and bottom slag) and the solid residue filtered out in step (1) in a ratio of 1:3, and grinding the mixture to 200 mesh; placing the ground mixture in a corundum crucible and heating it to 1300° C. at a heating rate of 10° C. / min, and keeping the temperature for 120 min to obtain a basic glass melt.

[0178] (5) The base glass melt is water quenched (or cooled at room temperature) to obtain glass slag, and the glass slag is dried at 105° C. to constant weight.

[0179] (6) Add the dried glass slag to the waste liquid in step (3), and add 3% calcium carbonate to mix to obtain a uniformly mixed slurry, inject and cure it for 120 minutes, and then demold it to obtain a foamed blank.

[0180] (7) The foamed blank is placed in a drying oven to dry, and then sintered at 1050° C. to obtain foamed glass-ceramics.

[0181] The properties of the foamed glass-ceramics prepared by sintering are shown in Table 5.

[0182] Embodiment 14

[0183] A method for extracting rare earth elements from gasified slag and preparing foamed glass-ceramics from gasified slag and fly ash, which is specifically prepared by the following steps:

[0184] (1) At room temperature, the gasification slag sample was mixed with citric acid (120 mM) and malic acid (80 mM) under continuous stirring (200 rpm) at a liquid-to-solid ratio of 200 mL / g, and the pH was controlled to 4 by dilute hydrochloric acid.

[0185] (2) After leaching, the solid residue and the leachate were separated by filtration through a 0.22 μm filter membrane.

[0186] (3) Add 0.0015% oxalate to the leachate in batches to separate the rare earth elements from other metals. Add sodium oxalate three times, 50 mL each time.

[0187] (4) mixing the organic incineration ash (fly ash and bottom slag) and the solid residue filtered out in step (1) in a ratio of 1:5, and grinding the mixture to 200 mesh; placing the ground mixture in a corundum crucible and heating it to 1300° C. at a heating rate of 10° C. / min, and keeping the temperature for 120 min to obtain a basic glass melt.

[0188] (5) The base glass melt is water quenched (or cooled at room temperature) to obtain glass slag, and the glass slag is dried at 105° C. to constant weight.

[0189] (6) Add the dried glass slag to the waste liquid in step (3), and add 3% calcium carbonate to mix to obtain a uniformly mixed slurry, inject and cure it for 120 minutes, and then demold it to obtain a foamed blank.

[0190] (7) The foamed blank is placed in a drying oven to dry, and then sintered at 1050° C. to obtain foamed glass-ceramics.

[0191] The properties of the foamed glass-ceramics prepared by sintering are shown in Table 5.

[0192] The properties of the prepared glass-ceramics were compared by using different ratios of the organic incineration ash in Examples 1, 12-14 and the solid residue filtered out in step (1). The results are shown in Table 5.

[0193] Table 5 is a comparison of the properties of foamed glass-ceramics of Examples 1, 12-14

[0194]

[0195]

[0196] It can be seen from Table 4 that different ratios of the organic incineration ash and the solid residue filtered in step (1) will cause changes in the stability of the formed basic glass. When the ash content is too high, the basic glass cannot be formed. When the ash content is too low, it will affect the corrosion resistance of the microcrystalline glass.

[0197] Embodiment 15

[0198] A method for extracting rare earth elements from gasified slag and preparing foamed glass-ceramics from gasified slag and fly ash, which is specifically prepared by the following steps:

[0199] (1) At room temperature, the gasification slag sample was mixed with citric acid (120 mM) and malic acid (80 mM) under continuous stirring (200 rpm) at a liquid-to-solid ratio of 200 mL / g, and the pH was controlled to 4 by dilute hydrochloric acid.

[0200] (2) After leaching, the solid residue and the leachate were separated by filtration through a 0.22 μm filter membrane.

[0201] (3) Add 0.0015% oxalate to the leachate in batches to separate the rare earth elements from other metals. Add sodium oxalate three times, 50 mL each time.

[0202] (4) mixing the organic incineration ash (fly ash and bottom slag) and the solid residue filtered out in step (1) in a ratio of 2:8, and grinding the mixture to 200 mesh; placing the ground mixture in a corundum crucible and heating it to 1300° C. at a heating rate of 10° C. / min, and keeping the temperature for 120 min to obtain a basic glass melt.

[0203] (5) The base glass melt is water quenched (or cooled at room temperature) to obtain glass slag, and the glass slag is dried at 105° C. to constant weight.

[0204] (6) Add the dried glass slag to the waste liquid in step (3), and add 3% calcium carbonate to mix to obtain a uniformly mixed slurry, inject and cure it for 120 minutes, and then demold it to obtain a foamed blank.

[0205] (7) The foamed blank is placed in a drying oven to dry, and then sintered at 950° C. to obtain foamed glass-ceramics.

[0206] Example 16

[0207] A method for extracting rare earth elements from gasified slag and preparing foamed glass-ceramics from gasified slag and fly ash, which is specifically prepared by the following steps:

[0208] (1) At room temperature, the gasification slag sample was mixed with citric acid (120 mM) and malic acid (80 mM) under continuous stirring (200 rpm) at a liquid-to-solid ratio of 200 mL / g, and the pH was controlled to 4 by dilute hydrochloric acid.

[0209] (2) After leaching, the solid residue and the leachate were separated by filtration through a 0.22 μm filter membrane.

[0210] (3) Add 0.0015% oxalate to the leachate in batches to separate the rare earth elements from other metals. Add sodium oxalate three times, 50 mL each time.

[0211] (4) mixing the organic incineration ash (fly ash and bottom slag) and the solid residue filtered out in step (1) in a ratio of 2:8, and grinding the mixture to 200 mesh; placing the ground mixture in a corundum crucible and heating it to 1300° C. at a heating rate of 10° C. / min, and keeping the temperature for 120 min to obtain a basic glass melt.

[0212] (5) The base glass melt is water quenched (or cooled at room temperature) to obtain glass slag, and the glass slag is dried at 105° C. to constant weight.

[0213] (6) Add the dried glass slag to the waste liquid in step (3), and add 3% calcium carbonate to mix to obtain a uniformly mixed slurry, inject and cure it for 120 minutes, and then demold it to obtain a foamed blank.

[0214] (7) The foamed blank is placed in a drying oven to dry, and then sintered at 1200° C. to obtain foamed glass-ceramics.

[0215] The properties of the prepared microcrystalline glass from the organic incineration ash in Examples 1, 15, and 16 and the solid residue filtered in step (1) at different crystallization temperatures are compared. The results are shown in Table 5.

[0216] Table 6 is a comparison of the properties of foamed glass-ceramics prepared in Examples 1, 15, and 16

[0217]

[0218] It can be seen that the final crystallization temperature will have an impact on the foaming agent. Too high a temperature will cause excessive decomposition of the foaming agent and melting of the material, resulting in a decrease in porosity and a significant reduction in the performance of the foamed microcrystalline glass.

[0219] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by technicians in this technical field within the essential scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A method for extracting rare earth elements from gasified slag and preparing foamed glass-ceramics from gasified slag and fly ash, characterized in that: The steps include: (1) mixing gasification slag with a small molecular organic acid, stirring continuously and uniformly, and controlling the pH value to 3 to 5 by using a buffer solution; (2) filtering the solid-liquid mixture prepared in step (1) to collect solid residue and leachate respectively; (3) adding oxalate to the leachate in batches to separate the rare earth elements, so as to separate the rare earth elements from other metals; Rare earth elements and waste liquid are filtered out; (4) mixing the fly ash from the organic incineration and the solid residue filtered in step (2), and grinding them to 200 mesh; placing the ground mixture in a corundum crucible and heating it to 1100-1300° C., and keeping it warm for a certain period of time to obtain a basic glass melt; (5) quenching the basic glass melt with water or cooling it at room temperature to obtain glass slag, and drying the glass slag to constant weight; (6) adding the dried glass slag to the waste liquid in step (3), and adding a certain amount of calcium carbonate to mix, to obtain a uniformly mixed slurry, injection molding and curing, and then demolding to obtain a foamed blank; (7) The foamed blank is placed in a drying oven for drying, and then sintered to obtain foamed glass-ceramics.

2. The method for extracting rare earth elements from gasified slag and preparing foamed glass-ceramics from gasified slag and fly ash according to claim 1, characterized in that: The sum of the mass fractions of SiO2, Al2O3 and Fe2O3 in the gasification slag is greater than 70wt%, and the mass fraction of residual carbon is less than 10wt%.

3. The method for extracting rare earth elements from gasified slag and preparing foamed glass-ceramics from gasified slag and fly ash according to claim 1, characterized in that: In the step (1), the small molecule organic acid is a mixture of citric acid and malic acid, and the liquid-solid ratio is 100-200 mL / g; the buffer solution is a dilute hydrochloric acid solution, and the pH of the solution is controlled to be 4.

4. The method for extracting rare earth elements from gasified slag and preparing foamed glass-ceramics from gasified slag and fly ash according to claim 3, characterized in that: The proportions of citric acid and malic acid added are respectively: citric acid: 50% to 70%, malic acid: 30% to 50%.

5. The method for extracting rare earth elements from gasified slag and preparing foamed glass-ceramics from gasified slag and fly ash according to claim 1, characterized in that: In the step (2), the filter membrane used for filtration is 0.22 μm.

6. The method for extracting rare earth elements from gasified slag and preparing foamed glass-ceramics from gasified slag and fly ash according to claim 1, characterized in that: In the step (3), 0.0015-0.0025% oxalate is added to the filtrate in batches.

7. The method for extracting rare earth elements from gasified slag and preparing foamed glass-ceramics from gasified slag and fly ash according to claim 1, characterized in that: In the step (4), the mass ratio of fly ash from organic incineration to solid residue is 1:3-5.

8. The method for extracting rare earth elements from gasified slag and preparing foamed glass-ceramics from gasified slag and fly ash according to claim 1, characterized in that: In the step (4), the temperature of the corundum crucible is increased at a rate of 5 to 20° C. / min, and the heat preservation time is 30 to 120 min.

9. The method for extracting rare earth elements from gasified slag and preparing foamed glass-ceramics from gasified slag and fly ash according to claim 1, characterized in that: In the step (5), the drying temperature is 100-110°C.

10. The method for extracting rare earth elements from gasified slag and preparing foamed glass-ceramics from gasified slag and fly ash according to claim 1, characterized in that: In the step (6), the waste liquid contains residual oxalate and oxalic acid, 3% calcium carbonate is added, and the generated calcium oxalate is used as a foaming agent.

11. The method for extracting rare earth elements from gasified slag and preparing foamed glass-ceramics from gasified slag and fly ash according to claim 1, characterized in that: In the step (6), the sintering temperature is 950-1200° C., and the sintering time is 30-120 min.

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