Method for cooperative safety disposal and all-component utilization of multi-source fluorine-containing solid waste

Abstract

The invention belongs to the technical field of solid waste resource utilization, and particularly relates to a method for collaborative safety disposal and all-component utilization of multi-source fluorine-containing solid waste. The method comprises the following steps: treating the multi-source fluorine-containing solid waste to obtain a standby material; the standby materials are placed in a mechanical activation and high-pressure environment integrated reaction device, a leaching agent is added for leaching, and after a leaching reaction, leaching residues and leaching liquid are filtered and separated in a vacuum mode; an oxidizing agent is added into the leachate for oxidation treatment, then an inducer is added, the pH value is adjusted, and cryolite and filtrate are obtained through crystallization and solid-liquid separation in sequence; the leaching residues and the silicon-containing solid waste are subjected to wet mixing according to a certain mass ratio, an alkali catalyst is added, and the alkali-activated gel material is obtained through curing, autoclaving and shaping treatment. According to the method, on the basis of complementarity of the components of the multi-source fluorine-containing solid waste, through innovative thinking and technical means of regulating solution ion composition by the inducer, multi-external-field synergistic enhanced leaching and the like, collaborative safe disposal and all-component utilization of the multi-source fluorine-containing solid waste are achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of comprehensive utilization of solid waste resources, and specifically relates to a method for coordinated safe disposal and full component utilization of multi-source fluorine-containing solid waste. Background Art

[0002] At present, a large amount of solid waste residues such as fluoridized gypsum, fluorosilicic slag and waste refractory materials rich in soluble fluoride will be produced during the preparation of hydrofluoric acid, synthesis of sodium fluoride and electrolytic aluminum production. Their significant leaching toxicity poses a serious threat to the ecological environment. At the same time, these fluorine-containing solid wastes mainly contain low-value components such as calcium sulfate, silica and nepheline, and lack high-value utilization properties. Therefore, achieving the coordinated detoxification and high-value utilization of the above-mentioned multi-source fluorine-containing solid wastes can provide scientific and technological support for promoting the construction of ecological civilization. The treatment technologies for the above-mentioned fluorine-containing solid wastes at home and abroad can be divided into the following categories:

[0003] The first method is leaching and landfilling, which mainly involves refining and compressing the fluorine-containing solid waste in turn, and landfilling it in a special site equipped with a leaching and circulation system. The solution leaching and rainwater runoff are collected through a collection pit to avoid the pollution of soluble fluoride to the surrounding soil and water sources. Its disadvantages are that it occupies a large amount of land resources, has a serious risk of environmental pollution, and valuable resources are not effectively utilized.

[0004] The second method is the disposal of building materials, which mainly utilizes the slow setting characteristics of calcium sulfate in fluorine-containing solid waste and the gelling activity of silicon-containing mineral phase, and uses the fluorine-containing solid waste crushed to a certain particle size as an admixture for cement or unburned cementitious material preparation. The soluble fluoride is deeply solidified in the cement or gelling system, thereby achieving the detoxification and resource utilization of fluorine-containing solid waste. Its disadvantage is that the sales price of fluorine-containing solid waste is low and the economic benefits are not obvious.

[0005] The third method is low-cost calcium source solidification, which mainly utilizes the solidification characteristics of soluble fluoride in fluorine-containing solid waste, and achieves stable solidification of soluble fluoride by adding low-cost calcium sources such as quicklime, slaked lime, and calcium hypochlorite. Its disadvantage is that soluble fluoride with high-value application potential is converted into CaF2, which fails to achieve high-value utilization. At the same time, the large amount of solid residue produced has the risk of secondary pollution, and there is a lack of resource utilization.

[0006] The fourth method is high-temperature treatment, which is mainly based on the heat volatilization characteristics of soluble fluoride in fluorine-containing solid waste. High-temperature equipment is used to heat treat fluorine-containing solid waste at 1000°C, and the soluble fluoride undergoes phase change and escapes in gaseous form, which is then recovered through the condensation system to achieve detoxification and disposal of fluorine-containing solid waste. The disadvantage is that high-temperature treatment consumes a lot of energy and produces carbon emissions, fluorine-containing flue gas seriously corrodes the lining of high-temperature equipment, and the remaining solid residue cannot be recycled. Summary of the invention

[0007] In order to solve the problems existing in the prior art, the main purpose of the present invention is to propose a method for the coordinated safe disposal and full component utilization of multi-source fluorine-containing solid waste, so as to realize the clean extraction and high-value product conversion of soluble fluoride in multi-source fluorine-containing solid waste and the full quantitative utilization of non-fluorine components. This method has the characteristics of low cost, short process and significant economic benefits.

[0008] To solve the above technical problems, according to one aspect of the present invention, the present invention provides the following technical solutions:

[0009] A method for coordinated safe disposal and full component utilization of multi-source fluorine-containing solid waste, comprising the following steps:

[0010] S1. Perform multi-stage crushing and screening on multi-source fluorine-containing solid waste to obtain spare materials;

[0011] S2, placing the spare material in a high-temperature ball mill with a polytetrafluoroethylene liner, adding a leaching agent for leaching, and after the leaching reaction is completed, vacuum filtering to separate the leached residue and the leaching liquid;

[0012] S3, adding an oxidant to the leaching solution for oxidation treatment;

[0013] S4, after oxidation treatment, adding an inducing agent and adjusting the pH, and sequentially performing crystallization and solid-liquid separation to obtain cryolite and a filtrate;

[0014] S5. Wet-mix the leached residue and silicon-containing solid waste in a certain mass ratio, add an alkali catalyst, and obtain an alkali-activated gel material after curing, autoclaving, and shaping.

[0015] As a preferred embodiment of the method for coordinated safe disposal and full component utilization of multi-source fluorine-containing solid waste described in the present invention, wherein: in the step S1, the multi-source fluorine-containing solid waste is one or more of fluorgypsum, fluorosilicic slag, and waste refractory materials.

[0016] As a preferred embodiment of the method for coordinated safe disposal and full component utilization of multi-source fluorine-containing solid waste described in the present invention, wherein: in the step S1, the particle size range of the spare material is one of <3mm, <1mm, <0.15mm, and <0.074mm.

[0017] As a preferred embodiment of the method for coordinated safe disposal and full component utilization of multi-source fluorine-containing solid waste described in the present invention, the liquid-solid ratio of the leaching agent to the spare material is 5:1-100:1, the leaching agent is one or both of an aqueous solution and a sodium aluminate solution, the leaching is a multi-stage leaching, the first stage leaching solution is a high-concentration leaching solution, and the second stage and subsequent multi-stage leaching solutions are low-concentration leaching solutions.

[0018] As a preferred embodiment of the method for coordinated safe disposal and full component utilization of multi-source fluorine-containing solid waste described in the present invention, wherein: in the step S2, the leaching temperature is 20-200°C, the leaching time is 10-180min, and the vibration frequency is 0-2000rpm.

[0019] As a preferred embodiment of the method for coordinated safe disposal and full component utilization of multi-source fluorine-containing solid waste described in the present invention, wherein: in the step S3, the leachate is a high-concentration leachate, the oxidant is one or more of hydrogen peroxide, potassium permanganate, sodium hypochlorite, and concentrated sulfuric acid, the amount of the oxidant added is 0.1-1% by volume, the oxidation temperature is 20-80°C, and the oxidation time is 10-60 min.

[0020] As a preferred embodiment of the method for coordinated safe disposal and full component utilization of multi-source fluorine-containing solid waste described in the present invention, in step S4, the filtrate is refluxed to the high-temperature ball mill in step S2.

[0021] As a preferred embodiment of the method for coordinated safe disposal and full component utilization of multi-source fluorine-containing solid waste described in the present invention, wherein: in the step S4, the inducer is one or more of aluminum fluoride, sodium aluminate, aluminum oxide, and aluminum hydroxide, the amount of the inducer added is 0.1-10% by volume, the pH is adjusted to 4-9, the crystallization temperature is 20-80°C, and the crystallization time is 1-24h.

[0022] As a preferred embodiment of the method for coordinated safe disposal and full component utilization of multi-source fluorine-containing solid waste described in the present invention, wherein: in step S5, the mass ratio of leached residue to silicon-containing solid waste is 1:99-40:60, and the amount of alkaline catalyst added is 1-18wt%.

[0023] As a preferred scheme of the method for coordinated safe disposal and full component utilization of multi-source fluorine-containing solid waste described in the present invention, wherein: in the step S5, the silicon-containing solid waste is one or more of electrolytic manganese slag, lead-zinc slag, gold slag, fly ash, and slag; the alkaline catalyst is one or more of quicklime, carbide slag, and slaked lime.

[0024] The beneficial effects of the present invention are as follows:

[0025] The present invention relies on the complementarity of the components of multi-source fluorine-containing solid wastes, and realizes the coordinated safe disposal and full component utilization of multi-source fluorine-containing solid wastes through innovative ideas and technical means such as inducing agents to regulate the solution ion composition and multi-external field synergistic enhanced leaching. The disposal process proposed by the present invention does not produce wastewater, waste gas, and waste residue, the leaching agent is low-cost and suitable for recycling, the soluble fluoride is converted into a high-value cryolite product, and the leached residue is suitable for the preparation of cementitious materials, which has significant environmental, economic and social benefits. DETAILED DESCRIPTION

[0026] The following will be described clearly and completely in conjunction with the technical solutions in the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] According to one aspect of the present invention, the present invention provides the following technical solution:

[0028] A method for coordinated safe disposal and full component utilization of multi-source fluorine-containing solid waste, comprising the following steps:

[0029] S1. Perform multi-stage crushing and screening on multi-source fluorine-containing solid waste to obtain spare materials;

[0030] S2, placing the spare material in a high-temperature ball mill with a polytetrafluoroethylene liner, adding a leaching agent for leaching, and after the leaching reaction is completed, vacuum filtration is performed to separate the leached residue and the leaching liquid;

[0031] S3, adding an oxidant to the leaching solution for oxidation treatment;

[0032] S4, after oxidation treatment, adding an inducing agent and adjusting the pH, and sequentially performing crystallization and solid-liquid separation to obtain cryolite and a filtrate;

[0033] S5. Wet-mix the leached residue and silicon-containing solid waste in a certain mass ratio, add an alkali catalyst, and obtain an alkali-activated gel material after curing, autoclaving, and shaping.

[0034] The multi-source fluorine-containing solid waste involved in the present invention is fluorine-containing solid waste generated by different industries, specifically, it can be one or more of fluorinated gypsum, fluorinated silicon slag, and waste refractory materials.

[0035] First, based on the rich soluble fluoride content in multi-source fluorine-containing solid waste, the present invention uses a multi-external field synergistic enhanced leaching device combined with a green leaching agent to efficiently extract soluble fluoride. In-situ mechanical activation during the leaching process can jointly increase the contact effect between solid particles and leaching agents from the two aspects of particle size reduction and specific surface area increase, thereby promoting the dissolution and removal of soluble fluoride. The leaching process is carried out in a closed device, and the leaching agent is gasified at a higher temperature to form a high-pressure environment. With the help of the lattice defects formed by in-situ mechanical activation, the diffusion rate of the leaching agent into the interior of the solid particles can be effectively increased. Under the multi-external field coupling effect of the above-mentioned in-situ mechanical activation and high-pressure environment, mechanical activation and high-pressure environment multi-external field strengthening effects are formed, and the leaching rate of soluble fluoride in multi-source fluorine-containing solid waste is ≥99.5%. At the same time, the leaching agent used in the present invention has the technical advantages of high solubility, low cost and no secondary pollution risk. More importantly, the residual filtrate after the conversion of low-concentration leachate and high-value products can be returned to the leaching link for recycling, showing significant economic and environmental sustainability.

[0036] In addition, the leachate is rich in Na and F elements. Through a simple process combination of oxidation treatment, inducer addition, pH control, and solid-liquid separation, a high-value conversion of soluble fluoride to cryolite is achieved. The oxidation treatment adjusts the solution environment and can remove some cyanide introduced by fluorine-containing solid waste. The inducer regulates the solution ion composition without introducing impurities to form a precursor solution with corresponding Na, Al, and F concentrations. The pH value of the precursor solution is regulated by acid-base adjustment to avoid Cl - 、SO4 2- 、NO 3- By introducing isoacid anions, cryolite products with high molecular weight ratio (≥2.8), qualified element composition (F≥52.0wt%, Al≥12.0wt%, Na≤52.0wt%) and low loss on ignition (≤2.5wt%) were successfully prepared using high-concentration leaching solution.

[0037] Finally, in one aspect of the present invention, multi-source fluorine-containing solid wastes with high soluble fluorine concentration and low soluble fluorine concentration are used for blending, thereby providing a suitable F-concentration for the subsequent cryolite precursor solution, avoiding the large amount of F - The residues cause secondary pollution. On the other hand, multi-source fluorine-containing solid waste with gelling activity and slow setting properties is used for blending. After the soluble fluorine leaching step, the remaining mixed leaching residue has both gelling activity and slow setting properties, which can not only ensure the mechanical properties of the prepared cementitious material, but also save the addition of retarders and reduce production costs. Through the above process design, the leaching residue was successfully used to prepare a cementitious material with qualified mechanical properties (≥4MPa) and leaching toxicity (F - ≤5mg / L) of cementitious materials.

[0038] Preferably, in step S1, the particle size range of the spare material is one of <3 mm, <1 mm, <0.15 mm, and <0.074 mm.

[0039] Preferably, in step S2, the liquid-to-solid ratio of the leaching agent to the spare material is 5:1-100:1, the leaching agent is one or both of an aqueous solution and a sodium aluminate solution, the leaching is a multi-stage leaching, the first stage leaching solution is a high-concentration leaching solution, and the second stage and subsequent multi-stage leaching solutions are low-concentration leaching solutions.

[0040] Preferably, in step S2, the leaching temperature is 20-200° C., the leaching time is 10-180 min, and the vibration frequency is 0-2000 rpm.

[0041] Preferably, in step S3, the leachate is a high-concentration leachate, the oxidant is one or more of hydrogen peroxide, potassium permanganate, sodium hypochlorite, and concentrated sulfuric acid, the amount of the oxidant added is 0.1-1% by volume, the oxidation temperature is 20-80° C., and the oxidation time is 10-60 min.

[0042] Preferably, in step S4, the filtrate is refluxed into the high-temperature ball mill in step S2.

[0043] Preferably, in step S4, the inducer is one or more of aluminum fluoride, sodium aluminate, aluminum oxide, and aluminum hydroxide, the amount of the inducer added is 0.1-10% by volume, the pH is adjusted to 4-9, the crystallization temperature is 20-80°C, and the crystallization time is 1-24h.

[0044] Preferably, in step S5, the mass ratio of leached residue to silicon-containing solid waste is 1:99-40:60, and the amount of alkaline catalyst added is 1-18wt%.

[0045] Preferably, in step S5, the silicon-containing solid waste is one or more of electrolytic manganese slag, lead-zinc slag, gold slag, fly ash, and slag; and the alkaline catalyst is one or more of quicklime, carbide slag, and slaked lime.

[0046] The technical solution of the present invention is further described below in conjunction with specific embodiments.

[0047] Example 1

[0048] A method for coordinated safe disposal and full component utilization of multi-source fluorine-containing solid waste, comprising the following steps:

[0049] S1. Perform multi-stage crushing and screening on the waste refractory materials in turn to obtain spare materials with a particle size range of <0.15 mm;

[0050] S2. Load the spare materials into a high-temperature ball mill with a polytetrafluoroethylene liner, and then add an aqueous solution at a liquid-to-solid ratio of 80:1. The leaching temperature is 80°C, the leaching time is 60 minutes, and the vibration frequency is 600rpm. After the leaching reaction is completed, separate the leaching residue, the first-stage leaching solution and the multi-stage leaching solution by vacuum filtration. Among them, the first-stage leaching solution is a high-concentration leaching solution, which is used for cryolite synthesis, and the multi-stage leaching solution is a low-concentration leaching solution, which is circulated in the leaching process. The leaching rate of soluble fluoride is 99.78%;

[0051] S3, add 0.2% hydrogen peroxide to the high concentration leaching solution for oxidation treatment, the oxidation temperature is 80℃, and the oxidation time is 40min. Among them, the leaching rate of highly toxic cyanide is 99.51%;

[0052] S4. After oxidation treatment, add 5% sodium aluminate to the high-concentration leaching solution, adjust the pH value to 6, and obtain cryolite product and filtrate through crystallization and solid-liquid separation in sequence. The filtrate is returned to the leaching process for recycling. The crystallization temperature is 20°C and the crystallization time is 24h;

[0053] S5. Wet-mix the leached slag and the lead-zinc slag in a mass ratio of 10:90, then add 15% of quicklime, and obtain an alkali-activated cementitious material through curing, autoclaving and shaping.

[0054] In this embodiment, the molecular ratio of synthetic cryolite is 2.88, the contents of F, Al and Na are 56.62%, 12.57% and 30.81% respectively, and the loss on ignition is 2.4wt%; the compressive strength of the alkali-activated cementitious material is 4.3MPa, and the F-leaching concentration is 2.81mg / L.

[0055] Example 2

[0056] A method for coordinated safe disposal and full component utilization of multi-source fluorine-containing solid waste, comprising the following steps:

[0057] S1. Perform multi-stage crushing and screening on the waste refractory materials and fluorgypsum in turn to obtain spare materials with a particle size range of <0.074 mm;

[0058] S2. Load the spare materials into a high-temperature ball mill with a polytetrafluoroethylene liner, and then add an aqueous solution at a liquid-to-solid ratio of 50:1. The leaching temperature is 60°C, the leaching time is 60 minutes, and the vibration frequency is 800rpm. After the leaching reaction is completed, separate the leaching residue and the primary leaching solution by vacuum filtration. Multi-stage leaching solution. Among them, the first-stage leaching solution is a high-concentration leaching solution, which is used for cryolite synthesis, and the multi-stage leaching solution is a low-concentration leaching solution, which is circulated in the leaching process. The leaching rate of soluble fluoride is 99.84%;

[0059] S3, add 0.1% hydrogen peroxide to the high concentration leaching solution for oxidation treatment, the oxidation temperature is 80℃, and the oxidation time is 30min. Among them, the leaching rate of highly toxic cyanide is 99.92%;

[0060] S4. After oxidation treatment, add 3% sodium aluminate to the high-concentration leaching solution, adjust the pH value to 7, and obtain cryolite product and filtrate through crystallization and solid-liquid separation in sequence. The filtrate is returned to the leaching process for recycling. The crystallization temperature is 20°C and the crystallization time is 12h;

[0061] S5 wet-mixes the leached slag with the lead-zinc slag in a mass ratio of 5:95, then adds 15% of quicklime, and obtains an alkali-activated cementitious material after curing, autoclaving and shaping.

[0062] In this embodiment, the molecular ratio of the synthetic cryolite is 2.87, the contents of F, Al, and Na are 56.20%, 12.72%, and 31.08%, respectively, and the loss on ignition is 2.2wt%; the compressive strength of the alkali-activated cementitious material is 5.0MPa, F - The leaching concentration is 1.121 mg / L.

[0063] Example 3

[0064] A method for coordinated safe disposal and full component utilization of multi-source fluorine-containing solid waste, comprising the following steps:

[0065] S1. Perform multi-stage crushing and screening on waste refractory materials, fluorinated silicon slag and fluorinated gypsum in turn to obtain spare materials with a particle size range of <0.15 mm;

[0066] S2. Load the spare material into a high-temperature ball mill with a polytetrafluoroethylene liner, and then add an aqueous solution at a liquid-to-solid ratio of 60:1. The leaching temperature is 70°C, the leaching time is 60 minutes, and the vibration frequency is 1000rpm. After the leaching reaction is completed, separate the leaching residue and the primary leaching solution by vacuum filtration. Among them, there are multiple stages of leaching solution. Among them, the first stage of leaching solution is a high-concentration leaching solution, and the high-concentration leaching solution is used for cryolite synthesis, and the multiple stages of leaching solution are low-concentration leaching solutions, and the low-concentration leaching solutions are circulated for the leaching process. The leaching rate of soluble fluoride is 99.67%;

[0067] S3, add 0.1% hydrogen peroxide to the high concentration leaching solution for oxidation treatment, the oxidation temperature is 60℃, and the oxidation time is 20min. Among them, the leaching rate of highly toxic cyanide is 99.74%;

[0068] S4. After oxidation treatment, 4% sodium aluminate is added to the high-concentration leaching solution, and the pH value is adjusted to 5. Crystallization and solid-liquid separation are performed in sequence to obtain cryolite products and filtrate, and the filtrate is returned to the leaching process for recycling. The crystallization temperature is 40°C and the crystallization time is 6h;

[0069] S5. Wet-mix the leached slag and the lead-zinc slag in a mass ratio of 15:85, then add 15% of quicklime, and obtain an alkali-activated cementitious material through curing, autoclaving and shaping.

[0070] In this embodiment, the molecular ratio of the synthetic cryolite is 2.80, the contents of F, Al, and Na are 56.13%, 12.95%, and 30.92% respectively, and the loss on ignition is 2.3wt%; the compressive strength of the alkali-activated cementitious material is 4.0MPa, F - The leaching concentration is 4.68 mg / L.

[0071] Example 4

[0072] A method for coordinated safe disposal and full component utilization of multi-source fluorine-containing solid waste, comprising the following steps:

[0073] S1. Perform multi-stage crushing and screening on waste refractory materials and fluorgypsum in turn to obtain spare materials with a particle size range of <0.074 mm;

[0074] S2. Load the spare materials into a high-temperature ball mill with a polytetrafluoroethylene liner, and then add sodium aluminate solution at a liquid-to-solid ratio of 60:1. The leaching temperature is 60°C, the leaching time is 60 minutes, and the vibration frequency is 1200rpm. After the leaching reaction is completed, separate the leaching residue and the primary leachate by vacuum filtration. Among them, there are multiple stages of leachate. Among them, the first stage of leachate is a high-concentration leachate, and the high-concentration leachate is used for cryolite synthesis, and the multiple stages of leachate are low-concentration leachates, and the low-concentration leachate is circulated for the leaching process. The leaching rate of soluble fluoride is 99.52%;

[0075] S3, add 0.05% hydrogen peroxide to the high concentration leaching solution for oxidation treatment, the oxidation temperature is 80℃, and the oxidation time is 60min. Among them, the leaching rate of highly toxic cyanide is 99.83%;

[0076] S4. After oxidation treatment, add 1% aluminum hydroxide to the high-concentration leaching solution, adjust the pH value to 5.5, and obtain cryolite product and filtrate through crystallization and solid-liquid separation in sequence. The filtrate is returned to the leaching process for recycling. The crystallization temperature is 20°C and the crystallization time is 12h;

[0077] S5. Wet-mix the leached residue and the slag in a mass ratio of 10:90, then add 15% of quicklime, and obtain an alkali-activated cementitious material after curing, autoclaving and shaping.

[0078] In this embodiment, the molecular ratio of the synthetic cryolite is 2.83, the contents of F, Al, and Na are 56.02%, 12.88%, and 31.10%, respectively, and the loss on ignition is 2.15wt%; the compressive strength of the alkali-activated cementitious material is 4.4MPa, F - The leaching concentration is 3.15 mg / L.

[0079] Comparative Example 1

[0080] A method for treating multi-source fluorine-containing solid waste comprises the following steps:

[0081] S1. Perform multi-stage crushing and screening on the waste refractory materials in turn to obtain spare materials with a particle size range of <0.15 mm;

[0082] S2. Load the spare materials into a magnetic stirring leaching container, then add an aqueous solution at a liquid-to-solid ratio of 80:1, the leaching temperature is 80°C, the leaching time is 60 minutes, and the stirring rate is 600r / min. After the leaching reaction is completed, separate the leaching residue and the primary leaching liquid by vacuum filtration. Among them, the high-concentration leaching liquid is used for cryolite synthesis, and the low-concentration leaching liquid is circulated for the leaching process. The leaching rate of soluble fluoride is 97.12%;

[0083] S3, add 0.2% hydrogen peroxide to the high concentration leaching solution for oxidation treatment, the oxidation temperature is 80℃, and the oxidation time is 40min. Among them, the leaching rate of highly toxic cyanide is 98.18%;

[0084] S4. After oxidation treatment, add 5% sodium aluminate to the high-concentration leaching solution, adjust the pH value to 6, and obtain cryolite product and filtrate through crystallization and solid-liquid separation in sequence. The filtrate is returned to the leaching process for recycling. The crystallization temperature is 20°C and the crystallization time is 24h;

[0085] S5. Wet-mix the leached slag and the lead-zinc slag in a mass ratio of 10:90, then add 15% of quicklime, and obtain an alkali-activated cementitious material through curing, autoclaving and shaping.

[0086] In this comparative example, the molecular ratio of synthetic cryolite is 2.53, the contents of F, Al and Na are 55.62%, 13.66% and 29.48% respectively, and the loss on ignition is 2.6wt%; the compressive strength of the alkali-activated cementitious material is 3.2MPa, and the F-leaching concentration is 64.88mg / L.

[0087] In this comparative example, when leaching is performed using a common leaching device, the leaching rate is reduced due to the lack of the synergistic strengthening effect of mechanical activation and high-pressure environment, and the subsequent cryolite synthesis and cementitious material preparation are affected.

[0088] Comparative Example 2

[0089] A method for treating multi-source fluorine-containing solid waste comprises the following steps:

[0090] S1. Perform multi-stage crushing and screening on the waste refractory materials and fluorgypsum in turn to obtain spare materials with a particle size range of <0.074 mm;

[0091] S2. Load the spare materials into a magnetic stirring leaching container, then add an aqueous solution at a liquid-to-solid ratio of 50:1, the leaching temperature is 60°C, the leaching time is 60 minutes, and the stirring rate is 800r / min. After the leaching reaction is completed, separate the leaching residue and the primary leaching liquid by vacuum filtration. Among them, the high-concentration leaching liquid is used for cryolite synthesis, and the low-concentration leaching liquid is circulated for the leaching process. The leaching rate of soluble fluoride is 97.45%;

[0092] S3, add 0.1% hydrogen peroxide to the high concentration leaching solution for oxidation treatment, the oxidation temperature is 80℃, and the oxidation time is 30min. Among them, the leaching rate of highly toxic cyanide is 98.33%;

[0093] S4. After oxidation treatment, add 3% sodium aluminate to the high-concentration leaching solution, adjust the pH value to 7, and obtain cryolite product and filtrate through crystallization and solid-liquid separation in sequence. The filtrate is returned to the leaching process for recycling. The crystallization temperature is 20°C and the crystallization time is 12h;

[0094] S5. Wet-mix the leached slag and the lead-zinc slag in a mass ratio of 5:95, then add 15% of quicklime, and obtain an alkali-activated cementitious material after curing, autoclaving and shaping.

[0095] In this comparative example, the molecular ratio of synthetic cryolite is 2.73, the contents of F, Al and Na are 55.48%, 12.92% and 30.08% respectively, and the loss on ignition is 2.2wt%; the compressive strength of the alkali-activated cementitious material is 3.4MPa, and the F-leaching concentration is 52.43mg / L.

[0096] This comparative example shows that under different particle sizes, when the integrated reaction device of mechanical activation and high-pressure environment is changed to an ordinary leaching device, the leaching rate will be reduced due to the lack of synergistic strengthening effect of mechanical activation and high-pressure environment, and the subsequent cryolite synthesis and cementitious material preparation will be affected.

[0097] The present invention relies on the complementarity of the components of multi-source fluorine-containing solid wastes, and realizes the coordinated safe disposal and full component utilization of multi-source fluorine-containing solid wastes through innovative ideas and technical means such as inducing agents to regulate the solution ion composition and multi-external field synergistic enhanced leaching. The disposal process proposed by the present invention does not produce wastewater, waste gas, and waste residue, the leaching agent is low-cost and suitable for recycling, the soluble fluoride is converted into a high-value cryolite product, and the leached residue is suitable for the preparation of cementitious materials, which has significant environmental, economic and social benefits.

[0098] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for the coordinated safe disposal and full component utilization of multi-source fluorine-containing solid waste, characterized in that: The steps include: S1. Perform multi-stage crushing and screening on multi-source fluorine-containing solid waste to obtain spare materials; S2, placing the spare material in a high-temperature ball mill with a polytetrafluoroethylene liner, adding a leaching agent for leaching, and after the leaching reaction is completed, vacuum filtering to separate the leached residue and the leaching liquid; S3, adding an oxidant to the leaching solution for oxidation treatment; S4, after oxidation treatment, adding an inducing agent and adjusting the pH, and sequentially performing crystallization and solid-liquid separation to obtain cryolite and a filtrate; S5. Wet-mix the leached residue and silicon-containing solid waste in a certain mass ratio, add an alkali catalyst, and obtain an alkali-activated gel material after curing, autoclaving, and shaping.

2. The method for coordinated safe disposal and full component utilization of multi-source fluorine-containing solid waste according to claim 1, characterized in that: In step S1, the multi-source fluorine-containing solid waste is one or more of fluorinated gypsum, fluorinated silicon slag, and waste refractory materials.

3. The method for coordinated safe disposal and full component utilization of multi-source fluorine-containing solid waste according to claim 1, characterized in that: In the step S1, the particle size range of the spare material is one of <3mm, <1mm, <0.15mm, and <0.074mm.

4. The method for coordinated safe disposal and full component utilization of multi-source fluorine-containing solid waste according to claim 1, characterized in that: In the step S2, the liquid-to-solid ratio of the leaching agent to the spare material is 5:1-100:1, the leaching agent is one or both of an aqueous solution and a sodium aluminate solution, the leaching is a multi-stage leaching, the first stage leaching solution is a high-concentration leaching solution, and the second stage and subsequent multi-stage leaching solutions are low-concentration leaching solutions.

5. The method for coordinated safe disposal and full component utilization of multi-source fluorine-containing solid waste according to claim 4, characterized in that: In step S2, the leaching temperature is 20-200° C., the leaching time is 10-180 min, and the vibration frequency is 0-2000 rpm.

6. The method for coordinated safe disposal and full component utilization of multi-source fluorine-containing solid waste according to claim 4, characterized in that: In step S3, the leachate is a high-concentration leachate, the oxidant is one or more of hydrogen peroxide, potassium permanganate, sodium hypochlorite, and concentrated sulfuric acid, the oxidant addition amount is 0.1-1% by volume, the oxidation temperature is 20-80° C., and the oxidation time is 10-60 min.

7. The method for coordinated safe disposal and full component utilization of multi-source fluorine-containing solid waste according to claim 1, characterized in that: In step S4, the filtrate is refluxed into the high temperature ball mill in step S2.

8. The method for coordinated safe disposal and full component utilization of multi-source fluorine-containing solid waste according to claim 1, characterized in that: In step S4, the inducing agent is one or more of aluminum fluoride, sodium aluminate, aluminum oxide, and aluminum hydroxide, the amount of the inducing agent added is 0.1-10wt%, the pH is adjusted to 4-9, the crystallization temperature is 20-80°C, and the crystallization time is 1-24h.

9. The method for coordinated safe disposal and full component utilization of multi-source fluorine-containing solid waste according to claim 1, characterized in that: In the step S5, the mass ratio of the leached residue to the silicon-containing solid waste is 1:99-40:60, and the amount of the alkaline catalyst added is 1-18 wt%.

10. The method for coordinated safe disposal and full component utilization of multi-source fluorine-containing solid waste according to claim 9, characterized in that: In step S5, the silicon-containing solid waste is one or more of electrolytic manganese slag, lead-zinc slag, gold slag, fly ash, and slag; and the alkaline catalyst is one or more of quicklime, carbide slag, and slaked lime.