Method for synergistically preparing fused salt potassium adsorbent by utilizing multi-source products of waste incineration power plant and application of fused salt potassium adsorbent

Abstract

The invention provides a method for synergistically preparing a molten salt potassium adsorbent by using multi-source products of a waste incineration power plant and application. The method comprises the following steps: mixing the waste incineration bottom slag with a silicon-aluminum additive to obtain first bottom slag, and screening to obtain second bottom slag; adding the second bottom slag into the landfill leachate concentrated solution, introducing NH3 and CO2, reacting, and filtering to obtain a first filter residue; adding alkali liquor into the first filter residues, carrying out hydrothermal reaction, and filtering to obtain second filter residues and second filtrate; washing the second filter residue, heating to a certain temperature, and purging gas to obtain a first potassium adsorbent; adjusting the pH value of the second filtrate, evaporating and concentrating to obtain a solid product, drying, heating to a certain temperature, and preserving heat to obtain a second potassium adsorbent. According to the method, various products such as the incinerator bottom slag of a waste incineration plant and the landfill leachate concentrated solution are jointly utilized, synergistic and efficient recycling is achieved, the potassium ion adsorbent of the high-temperature molten salt is finally prepared, and a new thought is provided for resource recycling of potassium in mixed alkali metal salt.

Description

Technical Field

[0001] The present invention relates to the technical field of resource utilization of refuse incineration bottom slag / refuse leachate concentrate, and particularly relates to a method and application for synergistically preparing a molten salt potassium adsorbent by using multi-source products of a refuse incineration power plant. Background Art

[0002] In recent years, with the acceleration of the urbanization process, the total amount of urban domestic waste treatment has been increasing year by year. Due to its advantages such as volume reduction, weight reduction, energy recovery, and biological inactivation, the refuse incineration technology has developed rapidly in China and has become the main method for domestic waste treatment in China. As of 2022, the proportion of refuse incineration in China has reached 79.9%, the daily incineration treatment capacity has reached 1.04 million tons / day, there are 2,046 refuse incinerators, and the number of related enterprises is 930. The above data indicate that there are a large number of refuse incineration power plants in China, and the resource utilization of their treatment products has also attracted much attention.

[0003] Refuse incineration bottom slag is the ash residue directly discharged from the incineration furnace, accounting for about 80% of the incineration products. Its main components are glass, ceramics, minerals, metals, etc., with relatively high silicon and aluminum contents. The residual harmful substances are lower than the national standards, belonging to general solid waste. The commonly used treatment method is direct landfill. However, direct landfill occupies a large area of land and may affect the nearby soil and groundwater due to heavy metals and soluble salts in it. Therefore, the resourceful disposal of bottom slag has become a current research hotspot and an urgent problem for the refuse incineration technology to achieve green and sustainable development. The prior art has disclosed technical solutions for the resource utilization of refuse incineration bottom slag, such as using domestic waste incineration bottom slag as a raw material to prepare ceramic membranes.

[0004] Refuse leachate concentrate is a kind of hazardous waste generated in domestic waste incineration power plants. It is the concentrate produced after the biological degradation of refuse leachate and treatment by membrane filtration (reverse osmosis membrane or nanofiltration membrane). It usually has a high content of inorganic salts and heavy metals and poor biodegradability. If not properly disposed of, it will cause serious ecological pollution. Although technologies such as metal-activated geopolymers and Fenton oxidation can effectively purify the leachate concentrate, the cost is very high. In this case, it is necessary to explore reasonable methods for the resource utilization of refuse leachate. For example, the prior art has disclosed a method for the resource utilization of refuse leachate, in which the modified refuse leachate is uniformly mixed with cement and modified dolomite in proportion, and then a composite iron ore pellet binder can be prepared after spray drying.

[0005] However, it can be seen that so far, most of the products in refuse incineration power plants are for their own resource applications, and there are few inventions that disclose methods for the good resourceful disposal of multiple products in refuse power plants according to local conditions and through synergistic effects. Summary of the Invention

[0006] In view of this, the present invention provides a method and application for synergistically preparing a molten salt potassium adsorbent using multi-source products from a waste incineration power plant, so as to achieve the synergistic and efficient resource utilization of multi-source products from the waste power plant and provide a new idea for the resource recovery / salt separation and potassium extraction process of mixed alkali metal salts.

[0007] To achieve the above object, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a method for synergistically preparing a molten salt potassium adsorbent using multi-source products from a waste incineration power plant, comprising the following steps:

[0009] Mix the waste incineration bottom slag with a silicon-aluminum additive to obtain a first bottom slag;

[0010] Screen the first bottom slag to obtain a second bottom slag;

[0011] Add the second bottom slag to the concentrated waste leachate, introduce NH3 and CO2, react, filter, and perform solid-liquid separation to obtain a first filter residue and a first filtrate;

[0012] Add an alkali solution to the first filter residue, perform a hydrothermal reaction, filter, and perform solid-liquid separation to obtain a second filter residue and a second filtrate;

[0013] Wash the second filter residue to obtain a third filter residue;

[0014] Dry the third filter residue, heat it to a certain temperature and keep it warm, and at the same time introduce a purge gas to obtain a first potassium adsorbent.

[0015] Preferably, it further includes:

[0016] Add a pH regulator to the second filtrate to adjust its pH to 7.5 - 10;

[0017] Evaporate and concentrate the second filtrate with adjusted pH, and collect the solid product;

[0018] Dry the solid product, heat it to a certain temperature and keep it warm to obtain a second potassium adsorbent.

[0019] Preferably, the silicon-aluminum additive includes at least one of fly ash, kaolin, and coal combustion slag;

[0020] The mass of the silicon-aluminum additive is 0 - 40% of the sum of the masses of the waste incineration bottom slag and the silicon-aluminum additive.

[0021] Preferably, in the step of adding the second bottom slag to the landfill leachate concentrate and introducing NH3 and CO2 for reaction, the reaction temperature is 20-60°C, the reaction time is 1-5 h, and the second bottom slag is ground during the reaction; the mass ratio of the landfill leachate concentrate to the second bottom slag is (3-20):1.

[0022] Preferably, in the step of adding an alkali solution to the first filter residue for hydrothermal reaction, the alkali solution includes at least one of a NaOH solution and a KOH solution;

[0023] The hydrothermal reaction temperature is 80-220°C, the time is 0.5-5 h, and the pressure is 0.1-1.0 Mpa.

[0024] Preferably, after drying the third filter residue at 55-105°C, it is heated to 400-1000°C and held for 1-6 h, and at the same time, a purge gas is introduced to obtain the first potassium adsorbent; the purge gas includes at least one of water vapor and carbon dioxide.

[0025] Preferably, after drying the solid product at 55-105°C, it is heated to 400-1000°C and held for 1-6 h to obtain the second potassium adsorbent.

[0026] Preferably, the pH regulator includes at least one of hydrochloric acid, sulfuric acid, acetic acid, citric acid, and carbon dioxide.

[0027] Preferably, after washing the second filter residue, obtaining the third filter residue specifically includes:

[0028] Adding water to the second filter residue for washing to obtain the third filter residue;

[0029] Among them, the number of washing times is at least once;

[0030] Each washing time is 0.5-2 h, and the mass ratio of water to the second filter residue during each washing is (3-10):1;

[0031] The first bottom slag is sieved through a 30-100 mesh sieve to obtain the second bottom slag.

[0032] In a second aspect, the present invention also provides an application of the first potassium adsorbent or the second potassium adsorbent prepared by the preparation method described above in selectively adsorbing K in a mixed alkali metal molten salt, + wherein the first potassium adsorbent product is insoluble K and the second potassium adsorbent product is soluble K.

[0033] The method and application for co-preparing a molten salt potassium adsorbent by using multi-source products of a waste incineration power plant according to the present invention have the following beneficial effects compared with the prior art:

[0034] 1. The method for co - preparing molten salt potassium adsorbent by using multi - source products of waste incineration power plant of the present invention includes the following steps: mixing waste incineration bottom slag with silica - alumina additive to obtain the first bottom slag; screening the first bottom slag to obtain the second bottom slag; adding the second bottom slag into the concentrated waste leachate, introducing NH3 and CO2, reacting, filtering, and performing solid - liquid separation to obtain the first filter residue and the first filtrate; adding alkali solution to the first filter residue, performing hydrothermal reaction, filtering, and performing solid - liquid separation to obtain the second filter residue and the second filtrate; washing the second filter residue to obtain the third filter residue; drying the third filter residue, heating it to a certain temperature and keeping it warm, and simultaneously introducing purge gas to obtain the first potassium adsorbent; adding a pH regulator to the second filtrate to adjust its pH to 7.5 - 10; evaporating and concentrating the second filtrate with adjusted pH, and collecting the obtained solid product; drying the solid product, heating it to a certain temperature and keeping it warm to obtain the second potassium adsorbent. The method for co - preparing molten salt potassium adsorbent by using multi - source products of waste incineration power plant of the present invention jointly utilizes various products such as the bottom slag of the waste incinerator, the concentrated waste leachate, and the alkali solution for flue gas deacidification in the waste incineration plant, realizing synergistic and efficient resource utilization;

[0035] 2. The molten salt potassium adsorbent co - prepared by using multi - source products of waste incineration power plant of the present invention can adsorb potassium ions in high - temperature molten salt. Among them, the first potassium adsorbent product is insoluble K, and the second potassium adsorbent product is soluble K, seeking an effective way for the selective resource recovery of industrial waste salts (mixed alkali metal salts). Specific Embodiments

[0036] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0037] It should be noted that the description order of the following embodiments does not limit the preferred order of the embodiments. Additionally, in the description of this application, the term "including" means "including but not limited to". The various embodiments of the present invention may exist in a range form; it should be understood that the description in a range form is only for convenience and brevity, and should not be construed as a rigid limitation on the scope of the present invention; therefore, it should be considered that the described range description has specifically disclosed all possible sub-ranges and individual values within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and individual numbers within the range, such as 1, 2, 3, 4, 5, and 6, which applies regardless of the range. Additionally, whenever a numerical range is indicated herein, it means including any cited number (fraction or integer) within the indicated range.

[0038] An embodiment of the present application provides a method for co-preparing a molten salt potassium adsorbent using multi-source products from a waste incineration power plant, including the following steps:

[0039] S1. Mix the waste incineration bottom slag with a silicon-aluminum additive to obtain a first bottom slag;

[0040] S2. Screen the first bottom slag to obtain a second bottom slag;

[0041] S3. Add the second bottom slag to the concentrated waste leachate, introduce NH3 and CO2, carry out a reaction, filter, and perform solid-liquid separation to obtain a first filter residue and a first filtrate;

[0042] S4. Add an alkali solution to the first filter residue, carry out a hydrothermal reaction, filter, and perform solid-liquid separation to obtain a second filter residue and a second filtrate;

[0043] S5. Wash the second filter residue to obtain a third filter residue;

[0044] S6. After drying the third filter residue, heat it to a certain temperature and keep it warm, and at the same time introduce a purge gas to obtain a first potassium adsorbent.

[0045] The method of the present invention for co-preparing a molten salt potassium adsorbent using multi-source products from a waste incineration power plant jointly utilizes various products such as the incinerator bottom slag of the waste incineration plant, the concentrated waste leachate, and the alkali solution for flue gas deacidification, etc., to achieve collaborative and efficient resource utilization. The ultimate goal is to prepare a potassium ion adsorbent for high-temperature molten salt, seeking an effective way for the selective resource recovery of industrial waste salts (mixed alkali metal salts).

[0046] The present invention uses the bottom ash from a waste incinerator as the initial reaction raw material, and appropriately adds a part of silicon-aluminum additive. After mixing and homogenizing, it becomes the first bottom ash. Specifically, the bottom ash from waste incineration is the ash and slag directly discharged from the incineration furnace, which belongs to general solid waste. Its characteristic is that the content of silicon-aluminum components is relatively high, and it is suitable as the initial reaction raw material for preparing potassium adsorbent. The first bottom ash is subjected to particle size screening to obtain the second bottom ash. The second bottom ash is added to the concentrated leachate of landfill leachate, and NH3 and CO2 are introduced for reaction. After filtration, solid-liquid separation is carried out to obtain the first filter residue and the first filtrate. The concentrated leachate of landfill leachate is a kind of hazardous waste generated in a waste incineration power plant, usually containing a high concentration of inorganic chlorides (such as salts like NaCl and KCl). Utilizing this characteristic, the concentrated leachate of landfill leachate can be used as one of the reaction raw materials to synergistically react with the bottom ash from waste incineration. Introducing gases such as NH3 and CO2 is to make them react with the chlorides in the concentrated leachate of landfill leachate to generate NH4Cl and NaHCO3, thereby dissolving and removing CaO and other Ca-containing compounds (generating CaCl2) in the second bottom ash. The amount of gas introduced needs to be determined according to the quality and concentration of the concentrated leachate of landfill leachate. The purpose of this step is to remove most of the non-Si / Al components (a small amount of soluble salts and a large amount of Ca-containing compounds) in the second bottom ash. After reaction and purification, the second bottom ash obtains the first filter residue, in which the Si / Al components are concentrated and the content is significantly increased. Strong alkalis such as NaOH are added to the first filter residue, and hydrothermal reaction is carried out at a certain temperature and pressure for a certain period of time, during which measures such as grinding and stirring are taken. The strong alkalis added to the first filter residue in this process need to be strong alkalis such as NaOH and KOH (the alkali solution for wet flue gas desulfurization in the incinerator can be considered). The purpose is to make them react with the SiO2, Al2O3 and some composite oxides (such as mullite, kaolin, etc.) components in the first filter residue to generate sodium silicate, sodium aluminate and analcime (sodalite, nepheline, geopolymers) and other substances. The sodium aluminosilicate salts with a smaller modulus and a small part of mineral salts in the product dissolve in the alkali solution, while the sodium aluminosilicate salts with a larger modulus and most of the mineral salts and the like remain as insoluble substances in the first filter residue. After the reaction is sufficient, the above mixture is subjected to solid-liquid separation by filtration to obtain the second filter residue and the second filtrate, and both are treated separately. For the second filter residue, clear water is added for washing, filtered after shaking for a period of time, and this water washing process is repeated several times to obtain the third filter residue. After drying the third filter residue, it is heated to a certain temperature and maintained for a certain period of time, and a purge gas is introduced for further activation. After the activation is completed, the first potassium adsorbent is obtained. The main components of the first potassium adsorbent are large molecular weight substances such as sodium aluminosilicate salts with a larger modulus, mineral salts and unreacted silicon-aluminum composite oxides, etc., which can adsorb potassium ions in the molten salt of mixed alkali metals and generate insoluble K products.

[0047] Specifically, the composition of the first bottom slag in the present invention is defined as follows: The compositions of the waste incineration bottom slag and the silicon-aluminum additive are analyzed (such as by XRF) to obtain the silicon and aluminum contents in the two substances respectively; the two are mixed in a certain proportion to obtain the first bottom slag, so that the mass ratio of silicon to aluminum in the first bottom slag is (1-3):1.

[0048] In some embodiments, in the waste leachate concentrate of the present invention, the Na + concentration is above 3.0 mol / L, and the K + concentration is above 0.75 mol / L. The measurement of the ion content in the waste leachate concentrate can be measured by an inductively coupled plasma mass spectrometer (ICP-MS).

[0049] In some embodiments, it further includes:

[0050] Adding a pH regulator to the second filtrate to adjust its pH to 7.5-10;

[0051] Evaporating and concentrating the second filtrate with adjusted pH, and collecting to obtain a solid product;

[0052] After drying the solid product, heating it to a certain temperature and keeping it warm to obtain the second potassium adsorbent.

[0053] Specifically, for the second filtrate, adjust its pH value to make the solution weakly alkaline, so that some silicon-aluminum components precipitate; the second filtrate is a strongly alkaline solution, mainly containing sodium aluminosilicate salts with a small modulus and some mineral salts, and these solutes need to be precipitated as solids; first, adjust the pH value of the second filtrate to the range of 7.5-10 (the solution is weakly alkaline) to precipitate some dissolved mineral salts such as analcime and nepheline; the pH regulator must be an acidic substance and can be one or several of the following substances: hydrochloric acid, sulfuric acid, acetic acid, citric acid, carbon dioxide, etc.; the pH value of the second filtrate can be measured by a pH meter or pH test paper; then, perform evaporation and concentration on the weakly alkaline filtrate and other treatments to precipitate the remaining silicon-aluminum solutes; after the second filtrate is adjusted to be weakly alkaline, then use operations such as evaporation and concentration to remove the liquid, so that the sodium aluminosilicate salts with a small modulus dissolved in water / alkali precipitate as solids and are mixed with the small amount of mineral salts precipitated previously; dry the solid product obtained after concentrating the filtrate, heat it to a certain temperature and keep it for a certain time for activation to obtain the second potassium adsorbent; the main components of the second potassium adsorbent are small molecular weight substances such as sodium aluminosilicate salts with a small modulus, and can adsorb potassium ions in the mixed alkali metal molten salt and generate soluble K products.

[0054] In some embodiments, the silicon-aluminum additive includes at least one of fly ash, kaolin, and coal combustion slag;

[0055] The mass of the silicon-aluminum additive is 0-40% of the sum of the masses of the waste incineration bottom slag and the silicon-aluminum additive.

[0056] In some embodiments, in the step of adding the second bottom slag to the landfill leachate concentrate, introducing NH3 and CO2, and carrying out the reaction, the reaction temperature is 20 to 60 °C, the reaction time is 1 to 5 h, and the second bottom slag is ground while the reaction is carried out; the mass ratio of the landfill leachate concentrate to the second bottom slag is (3 to 20):1; specifically, in the reaction process, the second bottom slag in the landfill leachate concentrate is wet mechanically ground, and the grinding reaction time is more than 0.5 h. The purpose of this step is to grind large particles into small particles, increase the solid-liquid contact area, accelerate the reaction process, and make the reaction more complete.

[0057] In some embodiments, the second bottom slag is added to the landfill leachate concentrate, NH3 and CO2 are introduced, the reaction is carried out, filtered, and solid-liquid separation is performed to obtain a first filter residue and a first filtrate; the filtration operation can adopt vacuum filtration, pressure filtration, centrifugation, percolation, etc. The second bottom slag is purified by reaction to obtain a first filter residue, in which the Si / Al components are concentrated and the content is significantly increased; the first filtrate can be recycled and used in the waste incineration system after treatment, realizing effective resource utilization; the main components of the first filtrate obtained after solid-liquid separation are alkalis (such as NH3·H2O, NaOH, Ca(OH)2, etc.) and salts (such as CaCl2, NH4Cl, NaHCO3, etc.), as well as a small amount of heavy metals and organic matters, which can be resourcefully utilized in the waste incinerator system after treatment: such as being sprayed back into the waste incineration furnace chamber for semi-dry or wet flue gas desulfurization and other purposes.

[0058] Specifically, the molar amount of NH3 introduced and the molar amount of CO2 are in excess compared to the sum of the molar amounts of Na + and K + in the landfill leachate concentrate. For example, the molar ratio of the molar amount of NH3 introduced and the molar amount of CO2 to the sum of the molar amounts of Na + and K + in the landfill leachate concentrate is (1 to 2):(1 to 2):1.

[0059] In some embodiments, in the step of adding an alkali solution to the first filter residue for hydrothermal reaction, the alkali solution includes at least one of a NaOH solution and a KOH solution; the hydrothermal reaction temperature is 80 - 220 °C (a slow reaction can occur at normal temperature, and the higher the temperature, the faster the reaction proceeds), the time is 0.5 - 5 h, and the pressure is 0.1 - 1.0 Mpa; the concentration of the alkali solution is 1 - 6 mol / L, and the mass ratio of the alkali solution to the first filter residue is (5 - 20):1; during the reaction process, measures such as grinding and stirring are taken. The grinding measure adopted in this process is for physical activation of the bottom residue, and the stirring measure is for making the reaction more complete; after the reaction is sufficient, the above mixture is subjected to solid-liquid separation by filtration to obtain a second filter residue and a second filtrate, and the two are treated separately; the filtration operation can adopt methods such as vacuum filtration, pressure filtration, centrifugation, and percolation; after solid-liquid separation, the second filter residue and the second filtrate need to adopt different treatment process flows to finally obtain two molten salt potassium ion adsorbents with their respective functions.

[0060] In some embodiments, after drying the third filter residue at 55 - 105 °C, it is heated to 400 - 1000 °C and kept warm for 1 - 6 h, and at the same time, a purge gas is introduced to obtain a first potassium adsorbent; the purge gas includes at least one of water vapor and carbon dioxide.

[0061] In some embodiments, after drying the solid product at 55 - 105 °C, it is heated to 400 - 1000 °C and kept warm for 1 - 6 h to obtain a second potassium adsorbent.

[0062] In some embodiments, the pH regulator includes at least one of hydrochloric acid, sulfuric acid, acetic acid, citric acid, and carbon dioxide.

[0063] In some embodiments, after washing the second filter residue to obtain the third filter residue, it specifically includes:

[0064] Adding water to the second filter residue for washing to obtain the third filter residue;

[0065] Among them, the number of washing times is at least once;

[0066] The time for each washing is 0.5 - 2 h, and the mass ratio of water to the second filter residue during each washing is (3 - 10):1.

[0067] Specifically, for the second filter residue, add clear water to the second filter residue for washing, filter after oscillating for a period of time, and repeat this water washing process several times to obtain the third filter residue; there are some impurities in the second filtrate remaining in the second filter residue, which need to be washed; the liquid-solid mass ratio of the clear water added each time to the second filter residue can be (3 - 10):1; the washing time can be 0.5 - 2 h; specifically, the number of washing times is at least once, for example, it can be 1 time, 2 times, or more than 2 times. The second filter residue is washed and the impurities are removed to obtain the third filter residue.

[0068] In some embodiments, the first bottom slag is sieved through a 30-100 mesh sieve to obtain the second bottom slag. The first bottom slag is screened for particle size using a 30-100 mesh sieve, and the fine particle slag after screening is the second bottom slag.

[0069] Based on the same inventive concept, the present invention also provides an application of the first potassium adsorbent or the second potassium adsorbent prepared by the above preparation method in selectively adsorbing K in a mixed alkali metal molten salt + wherein the first potassium adsorbent product is insoluble K and the second potassium adsorbent product is soluble K.

[0070] Specifically, the potassium adsorbent prepared by this method can selectively adsorb K in a mixed alkali metal molten salt + providing a new method for the separation and extraction of potassium in the mixed salt; the mixed alkali metal molten salt here refers to an ionic melt in a molten liquid state at high temperature with cations being one or more of Li + 、Na + 、K + (K must be included + ), and anions being one or more of inorganic anions such as Cl - 、CO3 2- 、SO4 2- ; the potassium adsorbent prepared by this method can selectively adsorb K in a mixed alkali metal molten salt + : the first potassium adsorbent product is insoluble K (non-water-soluble K), and the second potassium adsorbent product is soluble K (water-soluble K). After adsorption, the potassium adsorbent product can be further purified and recovered to achieve resource utilization. Generally speaking, the present invention not only proposes a new method for the multi-source collaborative utilization of products from waste incineration power plants, but also provides a new idea for the separation and extraction of potassium elements in mixed salts.

[0071] The following further describes the method and application of the present application for the collaborative preparation of molten salt potassium adsorbent using multi-source products from waste incineration power plants. This part further illustrates the content of the present invention in combination with specific embodiments, but should not be construed as a limitation to the present invention. Unless otherwise specified, the technical means used in the embodiments are conventional means well-known to those skilled in the art. Unless otherwise specified, the reagents, methods, and equipment used in the present invention are conventional reagents, methods, and equipment in the art.

[0072] Example 1

[0073] The embodiment of the present application provides a method for the collaborative preparation of molten salt potassium adsorbent using multi-source products from waste incineration power plants, including the following steps:

[0074] S1. Mix the bottom ash from waste incineration with a silicon-aluminum additive to obtain a first bottom ash. Here, the silicon-aluminum additive is fly ash, and the mass ratio of the bottom ash from waste incineration to the silicon-aluminum additive is 7:3. The mass ratio of silicon to aluminum in the first bottom ash is 2:1.

[0075] S2. Screen the first bottom ash through a 50-mesh sieve to obtain a second bottom ash.

[0076] S3. Add the second bottom ash to the concentrated solution of landfill leachate, introduce NH₃ and CO₂, and react at a temperature of 40 °C for 2 h. While reacting, grind the second bottom ash for 1 h. After the reaction is completed, perform suction filtration to separate the solid and liquid phases to obtain a first filter residue and a first filtrate. The mass ratio of the concentrated solution of landfill leachate to the second bottom ash is 5:1. Here, the concentration of Na in the concentrated solution of landfill leachate is 3.5 mol / L, the concentration of K is 0.85 mol / L, and the molar ratio of the introduced NH₃ and CO₂ to the sum of the molar amounts of Na and K in the concentrated solution of landfill leachate is 1:1:1. + concentration is 3.5 mol / L, the concentration of K + is 0.85 mol / L, and the molar amounts of the introduced NH₃ and CO₂ and the sum of the molar amounts of Na + and K + in the concentrated solution of landfill leachate have a molar ratio of 1:1:1.

[0077] S4. Add a NaOH solution to the first filter residue and perform hydrothermal reaction at a temperature of 160 °C and a pressure of 0.3 Mpa for 2 h. After the reaction is completed, perform suction filtration to separate the solid and liquid phases to obtain a second filter residue and a second filtrate. The concentration of the NaOH solution is 3 mol / L, and the mass ratio of the NaOH solution to the first filter residue is 12:1.

[0078] S5. After washing the second filter residue, obtain a third filter residue. Here, the number of washing times is 3 times, the washing time for each time is 1 h, and the mass ratio of water to the second filter residue for each washing is 8:1.

[0079] S6. Dry the third filter residue at 80 °C, then heat it to 800 °C and keep it warm for 3 h, and at the same time introduce the purge gas carbon dioxide to obtain a first potassium adsorbent.

[0080] S7. Add hydrochloric acid to the second filtrate to adjust its pH to 8.0.

[0081] S8. Evaporate and concentrate the second filtrate after adjusting the pH and collect the solid product.

[0082] S9. Dry the solid product at 70 °C, then heat it to 700 °C and keep it warm for 4 h to obtain a second potassium adsorbent.

[0083] The yield of the first potassium adsorbent prepared in Example 1 is 23.8%, and the molten salt potassium adsorption rate is 18.3% (non-water-soluble potassium); the yield of the second potassium adsorbent prepared in Example 1 is 38.6%, and the molten salt potassium adsorption rate is 46.7% (water-soluble potassium).

[0084] Note: The adsorbent yield refers to the ratio of the mass of the produced solid adsorbent to the mass of the initial raw material (the second bottom slag); the potassium adsorption rate refers to the ratio of the mass of the non-water-soluble potassium or water-soluble potassium adsorbed by the potassium adsorbent in the molten salt after adsorbing potassium ions to the mass of the potassium adsorbent product; the mass of the potassium adsorbent product refers to the total mass after the first potassium adsorbent or the second potassium adsorbent adsorbs non-water-soluble potassium or water-soluble potassium; among them, the potassium adsorption rate test method is: putting the first potassium adsorbent or the second potassium adsorbent into high-temperature liquid molten salt (the molten salt includes NaCl and KCl with a mass ratio of 6:4), and after the reaction, the potassium adsorbent product can be obtained, and then the potassium adsorption rate is calculated; the test methods of Examples 2 to 3 are the same as that of Example 1.

[0085] Example 2

[0086] The embodiment of the present application provides a method for co-preparing a molten salt potassium adsorbent by using multi-source products of a waste incineration power plant, including the following steps:

[0087] S1. Mix the waste incineration bottom slag with a silicon-aluminum additive to obtain a first bottom slag; wherein, the silicon-aluminum additive includes a mixture of fly ash and coal combustion slag with a mass ratio of 8:2; the mass ratio of the waste incineration bottom slag to the silicon-aluminum additive is 6:4; the mass ratio of silicon to aluminum in the first bottom slag is 3:1;

[0088] S2. Screen the first bottom slag through an 80-mesh sieve to obtain a second bottom slag;

[0089] S3. Add the second bottom slag to the concentrated waste leachate, introduce NH3 and CO2, react at a temperature of 60 °C for 6 h, and grind the second bottom slag during the reaction, with the grinding time being 2.5 h; after the reaction is completed, centrifuge and filter to separate the solid and liquid to obtain a first filter residue and a first filtrate; the mass ratio of the concentrated waste leachate to the second bottom slag is 15:1; among them, the concentration of Na in the concentrated waste leachate + is 4.0 mol / L, and the concentration of K + is 1.2 mol / L. The molar amount of the introduced NH3 and the molar amount of CO2 are in a molar ratio of 1.5:1:1 to the sum of the molar amounts of Na + and K + in the concentrated waste leachate;

[0090] S4. Add a NaOH solution to the first filter residue, and carry out a hydrothermal reaction at a temperature of 200 °C and a pressure of 0.7 Mpa for 4 h. After the reaction is completed, centrifuge and filter to separate the solid and liquid to obtain a second filter residue and a second filtrate; the concentration of the NaOH solution is 5 mol / L, and the mass ratio of the NaOH solution to the first filter residue is 5:1;

[0091] S5. After washing the second filter residue, a third filter residue is obtained; wherein, the number of washing times is 4 times; the washing time for each time is 2 h, and the mass ratio of water to the second filter residue during each washing is 5:1.

[0092] S6. After drying the third filter residue at 80 °C, it is heated to 900 °C and held for 5 h, and at the same time, purge gas steam is introduced to obtain the first potassium adsorbent.

[0093] S7. Hydrochloric acid is added to the second filtrate to adjust its pH to 9.0.

[0094] S8. The second filtrate with adjusted pH is evaporated and concentrated, and a solid product is collected.

[0095] S9. After drying the solid product at 70 °C, it is heated to 800 °C and held for 6 h to obtain the second potassium adsorbent.

[0096] The yield of the first potassium adsorbent prepared in Example 2 is 28.8%, and the molten salt potassium adsorption rate is 20.9% (non-water-soluble potassium); the yield of the second potassium adsorbent prepared in Example 2 is 33.1%, and the molten salt potassium adsorption rate is 35.2% (water-soluble potassium).

[0097] Example 3

[0098] The embodiment of the present application provides a method for co-preparing a molten salt potassium adsorbent by using multi-source products of a waste incineration power plant, including the following steps:

[0099] S1. Mix the waste incineration bottom slag with a silicon-aluminum additive to obtain a first bottom slag; wherein, the silicon-aluminum additive includes a mixture of fly ash and kaolin with a mass ratio of 7:3; the mass ratio of the waste incineration bottom slag to the silicon-aluminum additive is 8:2; the mass ratio of silicon to aluminum in the first bottom slag is 1:1.

[0100] S2. Screen the first bottom slag through a 60-mesh sieve to obtain a second bottom slag.

[0101] S3. Add the second bottom slag to the waste leachate concentrate, introduce NH3 and CO2, react at a temperature of 50 °C for 4 h, and grind the second bottom slag during the reaction for 2 h; after the reaction is completed, filter by percolation to separate the solid and liquid to obtain a first filter residue and a first filtrate; the mass ratio of the waste leachate concentrate to the second bottom slag is 10:1; wherein, the concentration of Na in the waste leachate concentrate + is 3.2 mol / L, and the concentration of K + is 0.95 mol / L, and the molar amounts of the introduced NH3 and CO2 and the molar ratio of the sum of the molar amounts of Na + and K + in the waste leachate concentrate are 1.5:1.5:1.

[0102] S4. Add NaOH solution to the first filter residue, and carry out hydrothermal reaction at a temperature of 180 °C and a pressure of 0.6 Mpa for 3 h. After the reaction is completed, filter by percolation method to separate the solid and liquid to obtain the second filter residue and the second filtrate; the concentration of the NaOH solution is 1 mol / L, and the mass ratio of the NaOH solution to the first filter residue is 20:1;

[0103] S5. After washing the second filter residue, obtain the third filter residue; wherein, the number of washing times is 3 times; the washing time for each time is 0.5 h, and the mass ratio of water to the second filter residue during each washing is 10:1;

[0104] S6. After drying the third filter residue at 80 °C, heat it to 500 °C and keep it warm for 4 h, and at the same time introduce the purge gas water vapor to obtain the first potassium adsorbent;

[0105] S7. Add hydrochloric acid to the second filtrate to adjust its pH to 9.5;

[0106] S8. Evaporate and concentrate the second filtrate after adjusting the pH, and collect the solid product;

[0107] S9. After drying the solid product at 70 °C, heat it to 600 °C and keep it warm for 5 h to obtain the second potassium adsorbent.

[0108] The yield of the first potassium adsorbent prepared in Example 3 is 30.3%, and the molten salt potassium adsorption rate is 19.0% (non-water-soluble potassium); the yield of the second potassium adsorbent prepared in Example 3 is 36.9%, and the molten salt potassium adsorption rate is 40.7% (water-soluble potassium).

[0109] The above is only the preferred embodiment of the present invention and is not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for synergistically preparing molten potassium adsorbent using multi-source products from a waste incineration power plant, characterized in that: The following steps are involved: Mixing the garbage incineration bottom ash with the silicon-aluminum additive to obtain a first bottom ash; Screening the first bottom slag to obtain a second bottom slag; The second bottom residue is added to the landfill leachate concentrate, NH3 and CO2 are introduced, reacted, filtered, and solid-liquid separated to obtain a first filter residue and a first filtrate; adding alkali solution to the first filter residue, performing hydrothermal reaction, filtering, and performing solid-liquid separation to obtain a second filter residue and a second filtrate; After washing the second filter residue, a third filter residue is obtained; After the third filter residue is dried, it is heated to a certain temperature and kept warm, and a purge gas is introduced at the same time to obtain a first potassium adsorbent.

2. The method for synergistically preparing molten salt potassium adsorbent using multi-source products from a waste incineration power plant as claimed in claim 1, characterized in that: Also includes: Adding a pH adjuster to the second filtrate to adjust the pH thereof to 7.5 to 10; The second filtrate after pH adjustment is evaporated and concentrated, and a solid product is obtained by collecting; The solid product is dried, heated to a certain temperature and kept warm to obtain a second potassium adsorbent.

3. The method for synergistically preparing molten salt potassium adsorbent by utilizing multi-source products of a waste incineration power plant as claimed in claim 1, characterized in that: The silicon-aluminum additive includes at least one of fly ash, kaolin, and coal-fired slag; The mass of the silicon-aluminum additive is 0 to 40% of the sum of the mass of the waste incineration bottom slag and the silicon-aluminum additive.

4. The method for synergistically preparing molten salt potassium adsorbent by utilizing multi-source products of a waste incineration power plant as claimed in claim 1, characterized in that: The second bottom slag is added to the concentrated leachate, and NH3 and CO2 are introduced to react. The reaction temperature is 20-60°C and the reaction time is 1-5 hours. The second bottom slag is ground while reacting. The mass ratio of the concentrated leachate to the second bottom slag is (3-20):

1.

5. The method for synergistically preparing molten salt potassium adsorbent by utilizing multi-source products of a waste incineration power plant as claimed in claim 1, characterized in that: In the step of adding alkali solution to the first filter residue to perform a hydrothermal reaction, the alkali solution includes at least one of a NaOH solution and a KOH solution; The hydrothermal reaction temperature is 80-220°C, the time is 0.5-5h, and the pressure is 0.1-1.0Mpa; The concentration of the alkali solution is 1-6 mol / L, and the mass ratio of the alkali solution to the first filter residue is (5-20):

1.

6. The method for synergistically preparing molten salt potassium adsorbent by utilizing multi-source products of a waste incineration power plant as claimed in claim 1, characterized in that: The third filter residue is dried at 55-105° C., and then heated to 400-1000° C. and kept warm for 1-6 hours, while introducing a purge gas to obtain a first potassium adsorbent; the purge gas includes at least one of water vapor and carbon dioxide.

7. The method for synergistically preparing molten salt potassium adsorbent by utilizing multi-source products from a waste incineration power plant as claimed in claim 2, characterized in that: The solid product is dried at 55-105° C., heated to 400-1000° C. and kept warm for 1-6 hours to obtain a second potassium adsorbent.

8. The method for synergistically preparing molten salt potassium adsorbent by utilizing multi-source products from a waste incineration power plant as claimed in claim 2, characterized in that: The pH adjuster includes at least one of hydrochloric acid, sulfuric acid, acetic acid, citric acid and carbon dioxide.

9. The method for synergistically preparing molten salt potassium adsorbent by utilizing multi-source products of a waste incineration power plant as claimed in claim 2, characterized in that: After washing the second filter residue, obtaining the third filter residue specifically comprises: adding water to the second filter residue for washing to obtain a third filter residue; Among them, the washing frequency is at least once; The washing time for each time is 0.5 to 2 hours, and the mass ratio of water to the second filter residue during each washing is (3 to 10):1; The first bottom slag is sieved through a 30-100 mesh sieve to obtain a second bottom slag.

10. A method according to any one of claims 1 to 9 for preparing a first potassium adsorbent or a second potassium adsorbent for selectively adsorbing K in a mixed alkali metal molten salt + applications, among which The first potassium adsorbent product is insoluble K, and the second potassium adsorbent product is soluble K.