A method for preparing a composite de-icing agent through comprehensive utilization of chlor-alkali salt mud solid waste and its application

Abstract

This invention provides a method and application for the comprehensive utilization of chlor-alkali salt mud solid waste to prepare a composite de-icing agent, belonging to the field of comprehensive utilization of solid waste resources and composite material synthesis technology. The invention first prepares a slurry by mixing chlor-alkali salt mud with water. Then, under the action of an acidification aid and an ionic liquid, organic and inorganic acids are added in a single step, followed by precipitation of the composite de-icing agent in an alcohol precipitation solution. The method of this invention achieves a salt mud utilization rate of 86.55-88.85% and an effective component extraction rate of 96.70-99.27%, especially for Ca... 2+ Na + K + Mg 2+ Al 3+ The extraction rates reached 95-99.99%, 99.9%, 99.9%, 85.5-95.0%, and 80.5-90.0%, respectively, and also improved the extraction efficiency of Ca in the solution. 2+ Na + K + Mg 2+ Al 3+ The precipitation rates reached 95.5-99.5%, 75.5-80.5%, 72.5-75.5%, 95.5-99.5%, and 71.5-75.5%, respectively, and the product yield reached 90.80-95.08%. It has broad prospects for snow melting and ice removal in low-temperature environments of -15℃ to -20℃.

Description

Technical Field

[0001] This invention belongs to the field of comprehensive utilization of solid waste resources and composite material synthesis technology, specifically relating to a method and application of preparing a composite de-icing agent through comprehensive utilization of chlor-alkali salt mud solid waste. Background Technology

[0002] Salt mud is a byproduct of primary brine refining in the chlor-alkali industry. Producing one ton of caustic soda generates 50-60 kg of solid waste salt mud. With a domestic chlor-alkali production capacity of approximately 50 million tons per year, this translates to about 2.5-3 million tons of salt mud annually. As a general industrial solid waste, improper disposal of salt mud can negatively impact the ecological environment and human life, and become a major problem for businesses.

[0003] The Shandong Haihua chlor-alkali plant has a capacity of 300,000 tons per year. Its dry-basis salt mud mainly consists of CaCO3 (approximately 58.5%), NaCl (approximately 19.5%), Mg(OH)2 (approximately 10%), Fe2O3 (approximately 0.08%), KCl (approximately 0.42%), and Al2O3 (approximately 1%), with the remainder being insoluble matter (approximately 10.5%, mainly CaSO4 and SiO2). Currently, most chlor-alkali industry salt mud is still disposed of through landfill. The implementation of new standards will increase the investment in salt mud treatment for chlor-alkali enterprises, and landfills will also have stricter requirements for accepting chlor-alkali salt mud. Therefore, the efficient and comprehensive utilization of chlor-alkali salt mud has become a hot topic of research for researchers both domestically and internationally.

[0004] Chloride-based snow-melting corrosion inhibitors are the most widely used snow-melting corrosion inhibitors both domestically and internationally due to their advantages of rapid snow melting and low cost. However, the liquid produced after melting is corrosive, causing serious damage to public facilities such as drainage systems, farmland, and railway tracks, as well as the ecological environment. To effectively solve this problem, chlorine-free organic environmentally friendly snow-melting corrosion inhibitors such as calcium magnesium acetate (CMA) have emerged. However, CMA is expensive, has poor snow-melting and ice-de-thawing effects, and becomes ineffective below -10°C, limiting its application in snow-melting and ice-de-thawing fields. Therefore, developing a composite snow-melting agent with a low freezing point, good snow-melting effect, environmental friendliness, and low cost has broad application prospects. Currently, there is no research on the in-situ reaction preparation of composite snow-melting agents from solid waste such as salt mud.

[0005] Currently, the method for preparing de-icing agents from chlor-alkali salt mud solid waste involves mixing salt mud with water to form a slurry, then reacting it with acidifying reagents such as hydrochloric acid, followed by evaporation and concentration to obtain a high-concentration calcium-magnesium solution. A corrosion inhibitor is then added, followed by spray drying and granulation to obtain the de-icing agent. During the acidification process, researchers sometimes reduce the risk of overflow by adding hydrochloric acid or increasing the volume of the reaction vessel to mitigate the potential for overflow caused by the vigorous reaction of hydrochloric acid with salt mud and the generation of large amounts of carbon dioxide gas. However, this approach prolongs the total acidification reaction time and reduces the utilization rate of the reaction vessel volume. Alternatively, researchers may reduce the risk of overflow by decreasing the instantaneous concentration of acidifying reagents such as hydrochloric acid and controlling the rate of carbon dioxide gas generation, i.e., by increasing the liquid-to-solid ratio of the water-to-salt mud slurry. However, the addition of large amounts of water leads to a decrease in the calcium-magnesium concentration in the reaction system, thereby increasing the cost of evaporation and concentration, resulting in poor economic efficiency. Therefore, a rapid preparation method for de-icing agents with high salt mud utilization, high-concentration calcium-magnesium solutions, and low cost is a focus of attention for enterprises and researchers.

[0006] Chinese invention patent document CN103133849A discloses an inorganic-organic composite environmentally friendly de-icing agent. This method comprises anhydrous magnesium chloride and / or anhydrous calcium chloride, anhydrous sodium acetate and / or anhydrous potassium acetate, zinc sulfate, sodium gluconate, and a corrosion inhibitor to form the de-icing agent. This belongs to the research of a blended formulation of de-icing agents and does not involve in-situ chemical preparation of de-icing agents or the resource utilization of salt mud. Furthermore, the de-icing agent contains calcium chloride and zinc sulfate. When used for de-icing, it produces water-insoluble calcium sulfate precipitates, which not only affect the de-icing effect but also pollute the environment and road surfaces.

[0007] Chinese invention patent document CN102399534A discloses an organic-inorganic composite environmentally friendly snow-melting agent and its preparation method. This method involves simply mixing, crushing, and sieving formate, nitrate, sulfate, acetate, and urea, followed by mixing with calcium carbonate to obtain the snow-melting agent. However, because the salts have different densities, particle shapes, and sizes, simple mixing easily leads to uneven mixing, and the addition of water-insoluble calcium carbonate severely affects the snow-melting and ice-removing effect. Summary of the Invention

[0008] The technical problem this invention aims to solve is to provide a method for preparing de-icing agents from chlor-alkali salt mud. This method effectively overcomes the problems of excessively long addition time of acidifying reagents or low volume utilization of the acidifying reactor during the acidification process. It also addresses issues such as high energy consumption in de-icing agent preparation, high cost of chlorine-free organic environmentally friendly de-icing agents, high freezing point of single chlorine-free organic environmentally friendly de-icing agents, poor environmental performance of chloride-based de-icing agents, and poor de-icing performance due to simple blending of composite de-icing agents. Simultaneously, it solves the problem of comprehensive utilization of salt mud, realizing value-added utilization of salt mud, turning waste into treasure, reducing solid waste emissions, and eliminating waste liquid emissions. This effectively promotes the healthy development of the chlor-alkali industry and demonstrates broad prospects for industrial application.

[0009] To address the above problems, the technical solution of this invention is a method for preparing a composite de-icing agent through comprehensive utilization of chlor-alkali salt sludge solid waste, comprising the following steps:

[0010] (1) The solid phase in the salt mud is crushed into 100-500 mesh particles, and then mixed with water to form a slurry. The ratio of the mass of salt mud to water in the slurry on a dry basis is controlled to be 1g:2-4mL. Then, acidification aid and ionic liquid are added to the slurry to obtain the first mixed solution.

[0011] (2) Prepare an acidification solution by mixing inorganic acid and organic acid. Add the acidification solution to the first mixed solution at one time while stirring. React at 35-55℃ for 0.5-2h. After separation, obtain the residue and the second mixed solution.

[0012] (3) Mix water-soluble alcohol organic solvents, ketone organic solvents and ester organic solvents to prepare an alcohol precipitation solution, add the alcohol precipitation solution to the second mixed solution to carry out the alcohol precipitation reaction, and obtain a third mixed solution;

[0013] (4) The third mixed solution is separated to obtain crude composite de-icing agent and fourth mixed solution; the crude composite de-icing agent is dried to obtain composite de-icing agent; the fourth mixed solution is distilled under reduced pressure to obtain a gaseous mixture of water-soluble alcohol organic solvent, ketone organic solvent, ester organic solvent and water at the top; the mixture of water-soluble alcohol organic solvent, ketone organic solvent, ester organic solvent and water is condensed to obtain fifth mixed solution; the bottom is the reaction residue, which is recycled.

[0014] (5) Add 3A molecular sieve to the fifth mixed solution for adsorption, and then separate the solution to obtain alcohol precipitation solution and adsorbed 3A molecular sieve. Return the alcohol precipitation solution to step (4) for recycling and reuse. The adsorbed 3A molecular sieve is regenerated and reused.

[0015] Further, in step (1), the acidifying agent is one of allyl polyoxyalkyl epoxy ether, allyl alcohol polyoxyalkyl ether, or nonylphenol polyoxyethylene ether; the ionic liquid is one of 1-propylamino-3-butylimidazolium tetrafluoroborate, 1-(2-aminoethyl)-2-methylpyrazole bromide, or tetrahedral ammonium bromide.

[0016] Further, in step (1), the ratio of the amount of acidifying agent added to the total amount of water in the first mixed solution is 0.005-0.01g:1mL; the ratio of the amount of ionic liquid added to the total amount of water in the first mixed solution is 0.05-0.1g:1mL.

[0017] Furthermore, in step (2), the inorganic acid is one or two of concentrated hydrochloric acid and nitric acid; the organic acid is one or two of acetic acid and formic acid; and the ratio of inorganic acid to organic acid in the acidification solution is 1 mol: 1-3 mol.

[0018] Further, in step (2), the stirring speed is 200-400 r / min; the mass ratio of the acidifying reagent to the salt mud in the first mixed solution on a dry basis is 0.015-0.020 mol: 1 g.

[0019] Furthermore, in step (3), the water-soluble alcohol organic solvent is one of methanol or ethanol; the ketone organic solvent is one of acetone or ethyl ketone; and the ester organic solvent is one of ethyl acetate or methyl acetate.

[0020] Further, in step (3), the volume ratio of alcohol organic solvent to ketone organic solvent and ester organic solvent in the alcohol precipitation solution is 2-4:1:1-4; the volume ratio of the amount of alcohol precipitation solution added to the volume ratio of the second mixed solution is 6-10:1.

[0021] Furthermore, in step (3), the alcohol precipitation reaction conditions are: alcohol precipitation temperature 5-49℃, alcohol precipitation time 0.5-1h, and stirring speed 500-800r / min.

[0022] Furthermore, in step (4), the drying conditions are: vacuum drying at 40-60℃ and vacuum drying time of 1-2h; the reaction residue is recycled and reused by returning the reaction residue to step (1) to be used as water.

[0023] Further, in step (5), the adsorption conditions are: the amount of 3A molecular sieve added is 3-8% of the mass of the fifth mixed solution, the adsorption time is 0.5-1h, and the stirring speed is 200-300r / min.

[0024] Furthermore, in step (5), the conditions for regenerating and reusing the adsorbed 3A molecular sieve are: vacuum drying temperature 100-150℃ and vacuum drying time 1-3h.

[0025] Another object of the present invention is to provide an application of a composite de-icing agent prepared by the above method, which is applied to de-icing and ice melting at temperatures ranging from -15°C to -20°C.

[0026] The beneficial effects of this invention are as follows:

[0027] (1) The present invention grinds the solid phase in the salt mud into fine particles of 100-500 mesh, which helps to promote the acidification reaction process and improves the utilization rate of salt mud and the extraction rate of effective components in salt mud.

[0028] (2) By adding ionic liquids and acidifying agents, this invention not only saves reaction time but also prevents solution overflow. The ionic liquids have three functions: first, they improve the dispersibility of the salt mud, reducing the surface tension of the solution; second, they absorb carbon dioxide gas generated during the acidification reaction in situ, thereby reducing the risk of the reaction solution solidifying, working in conjunction with the acidifying agents; and third, they increase the Ca2+ content. 2+ Na + K + Mg 2+ Al 3+ The precipitation rate is increased. In addition, the addition of acidifying aids disperses large carbon dioxide bubbles into smaller bubbles, suppressing large carbon dioxide bubbles in the reaction. The smaller bubbles are more easily broken during the stirred reaction, which has a synergistic effect with the in-situ absorption of carbon dioxide by ionic liquids, jointly optimizing the acidification reaction. Therefore, there is no need to control the dropping rate of the acidifying liquid, and the acidifying liquid can be added directly in one go, laying the foundation for continuous industrial operation.

[0029] (3) This invention optimizes the solid-liquid ratio, reaction temperature, reaction time, ratio of inorganic and organic acids in the acidification solution, and amount of acidification solution added to salt mud and water. While ensuring a high concentration of calcium-magnesium-containing solution, it achieves high utilization of salt mud and extraction of effective components from the salt mud. The utilization rate of salt mud reaches 86.55-88.85%, and the extraction rate of effective components from the salt mud reaches 96.70-99.27%, especially for Ca... 2+ Na + K + Mg 2+ Al 3+The extraction rates reached 95-99.99%, 99.9%, 99.9%, 85.5-95.0%, and 80.5-90.0% respectively, with only a portion of residue being discharged throughout the process, thus reducing the amount of salt mud discharged and contributing to the healthy development of the chlor-alkali industry. Furthermore, the price of hydrochloric acid in the chlor-alkali industry is mostly inverted. Because the acidification solution contains inorganic acid salts, hydrochloric acid can be recycled, which helps extend the downstream applications of hydrochloric acid in the chlor-alkali industry and increase the added value of the products.

[0030] (4) The alcohol precipitation method of the present invention does not involve a chemical reaction. It only optimizes the volume ratio of water-soluble alcohol organic solvents, ketone organic solvents, and ester organic solvents, the amount of alcohol precipitation solution added, the alcohol precipitation reaction temperature, the alcohol precipitation reaction time, and the alcohol precipitation stirring rate to control the Ca in the solution. 2+ Na + K + Mg 2+ Al 3+ The precipitation rates reached 95.5-99.5%, 75.5-80.5%, 72.5-75.5%, 95.5-99.5%, and 71.5-75.5% respectively, basically achieving Ca... 2+ Mg 2+ All precipitation and Na + K + Al 3+ Most of the product precipitated, especially with a yield of 90.80-95.07%.

[0031] (5) The 3A molecular sieve in this invention can adsorb and treat water in the alcohol precipitation solution. By optimizing the amount of 3A molecular sieve added to adsorb water, the water content can be reduced to below 0.5%, which helps to recycle the alcohol precipitation solution and reduce the operating cost of the process. At the same time, the 3A molecular sieve can be repeatedly regenerated through drying, realizing a circular economy.

[0032] (6) This invention achieves efficient and complete utilization of resources. The recycling of 3A molecular sieve and alcohol precipitation solution reduces operating costs and improves product competitiveness. At the same time, the reaction residue is used as water in step (1) to disperse salt mud, achieving zero discharge of waste liquid, which greatly reduces production costs and has significant environmental and economic benefits.

[0033] (7) The present invention uses an organic solvent alcohol precipitation method, which reduces drying conditions compared with the traditional evaporation and concentration method, thereby reducing energy consumption and improving product competitiveness. At the same time, the selected water-soluble alcohol, ketone and ester organic solvents have low boiling points and low cost, are easy to distill and recycle, further reducing process operating costs.

[0034] (8) The application of the composite de-icing agent of the present invention, since the composite de-icing agent contains one or both of the inorganic salts of chloride or nitrate, and the organic salts of formate or acetate.

[0035] One or two types of salts and trace elements (K, Al) are used to regulate the freezing point of the snow-melting agent, achieving a freezing point of -18.2 to -24.8℃, which meets or exceeds the national Class I and Class II snow-melting agent standards. Furthermore, under the requirements of GB / T 2351-2017 Snow-melting Agents, the solid dissolution rate of this composite snow-melting agent is 7.87-9.26 g / min, which is 1.17-1.38 times that of traditional blended composite snow-melting agents, demonstrating excellent prospects for snow and ice melting. Attached Figure Description

[0036] Figure 1 The X-ray diffraction (XRD) structure diagram of the composite de-icing agent obtained in step (4) of Examples 1-3 is shown below.

[0037] Figure 2 The image shows the scanning electron microscope (SEM) morphology of the composite de-icing agent obtained in step (4) of Example 1. Detailed Implementation

[0038] The present invention will now be described in detail with reference to the embodiments and accompanying drawings, but the scope of protection of the present invention is not limited thereto.

[0039] In one specific embodiment of the present invention, the high-moisture vertical pulverizer consists of a motor, a screen, pulverizing blades, and a frame. The high-moisture vertical pulverizer is model LPS500, brand Xinruiheng, with an output voltage of 380V and a power of 11kW. The solid content analyzer consists of a weighing module, a heating module, and a control system. The solid content analyzer is model GSY-G3, brand Shenfen Instruments, with an output voltage of 220V, a weighing range of 0-70g, and a moisture content measurement range of 0.01-100%. Example 1

[0040] (1) The solid phase in the salt mud was crushed into 500 mesh particles by a high-moisture vertical pulverizer. After crushing, the moisture content of the salt mud was measured to be 20% by a solid content detector. 625g of crushed salt mud was weighed and then 1125mL of pure water was added and mixed evenly to prepare a slurry. 10.0g of allyl polyoxyalkyl epoxy ether and 93.75g of 1-propylamino-3-butylimidazolium tetrafluoroborate were added to the slurry and mixed evenly to obtain the first mixed solution.

[0041] (2) Prepare an acidification solution by mixing 2.8 mol of 37% concentrated hydrochloric acid, 3.6 mol of glacial acetic acid and 2 mol of formic acid. Add the acidification solution to the first mixed solution at a stirring speed of 300 r / min. React at 45°C for 1 h. After filtration and separation, obtain the residue and the second mixed solution.

[0042] (3) Prepare an alcohol precipitation solution by mixing methanol, acetone and ethyl acetate in a volume ratio of 3:1:3. Take 1000 mL of the second mixed solution and add 7000 mL of alcohol precipitation solution to the second mixed solution to carry out the alcohol precipitation reaction. Control the alcohol precipitation temperature at 25℃, the alcohol precipitation time at 0.8 h and the stirring rate at 600 r / min to obtain the third mixed solution.

[0043] (4) The third mixed solution is filtered and separated to obtain crude composite de-icing agent and fourth mixed solution. The crude composite de-icing agent is dried under vacuum at 50°C for 1.5h to obtain composite de-icing agent. The fourth mixed solution is distilled under reduced pressure in a distillation tower. A mixture of gaseous methanol, acetone, ethyl acetate and water is obtained at the top. The mixture of gaseous methanol, acetone, ethyl acetate and water is condensed to obtain fifth mixed solution. The reaction residue is obtained at the bottom of the distillation tower and is returned to step (1) as water for recycling.

[0044] (5) After mixing the fifth mixed solution with the 3A molecular sieve, the adsorption treatment is carried out. The amount of 3A molecular sieve added is controlled to be 5.5% of the mass of the fifth mixed solution, the adsorption time is 0.8h, and the stirring speed is 250r / min. After filtration and separation, the alcohol precipitation solution and the adsorbed 3A molecular sieve are obtained. The alcohol precipitation solution is returned to step (4) for recycling. The adsorbed 3A molecular sieve is vacuum dried at 120℃ for 2h and then regenerated for recycling.

[0045] The residue in step (2) was dried and weighed. The weighing results are shown in Table 1.

[0046] In step (2), the second mixed solution was subjected to inductively coupled plasma atomic emission spectrometry (ICP) for Na... + Ca 2+ Mg 2+ K + Al 3+ Concentration test results are shown in Table 1.

[0047] In step (4), the fourth mixed solution is subjected to ICP Na + Ca 2+ Mg 2+ K + Al 3+ Concentration test results are shown in Table 1.

[0048] In step (4), the composite de-icing agent was subjected to X-ray diffraction (XRD) structure, scanning electron microscopy (SEM) morphology, and yield tests. The test results are shown in the figure below. Figure 1 , Figure 2 Table 1 and Table 2.

[0049] The moisture content of the alcohol precipitation solution in step (5) was tested, and the test results are shown in Table 1.

[0050] The utilization rate test procedure for salt mud is as follows: Weigh the dried residue and calculate its mass using the formula: Y 总 = (m0-m1) / m0×100%, Y 总 The percentage represents the utilization rate of salt mud, %; m0 represents the dry weight of salt mud, g; and m1 represents the dry weight of the residue, g. Where m0 is 500 g.

[0051] The procedure for testing the extraction rate of effective components in salt mud is as follows: Weigh the dried residue and calculate its mass using the formula: Y 有效 = (m0-m1) / (m0×(1-X)) 酸性不溶物 ))×100%, Y 有效 X represents the extraction rate of effective components from salt mud, %; m0 represents the dry weight of salt mud, g; 酸性不溶物 , where m1 is the content of acidic insoluble matter in the dry base salt mud, %; and m1 is the mass of the residue after drying, g. Among them, X 酸性不溶物 The dry base salt mud contains 10.5% SiO2 and 500g of CaSO4.

[0052] ICP Na + Ca 2+ Mg 2+ K + Al 3+ Concentration testing method: Standard curves for different concentrations of calcium, magnesium, potassium, or aluminum solutions were prepared with deionized water using sodium chloride, calcium chloride, calcium acetate, calcium formate, magnesium chloride, magnesium acetate, magnesium formate, potassium chloride, aluminum chloride, aluminum acetate, or aluminum formate, respectively. The average error was ≥0.999. The test sample was analyzed based on the standard curves of sodium, calcium, magnesium, potassium, or aluminum solutions to obtain the Na+ concentration. + Concentration, Ca 2+ Concentration, Mg 2+ Concentration, K + Concentration, Al 3+ concentration.

[0053] Na in salt mud + Ca 2+ Mg 2+ K + Al 3+The extraction rate test is performed as follows: The Na in the second mixed solution in step (2) + Ca 2+ Mg 2+ K + Al 3+ The concentration and volume are used to determine the remaining amounts (mol) of Ca, Mg, K, and Al in the fourth mixed solution. Given 500g of salt mud, and the known mass fractions of NaCl, CaCO3, Mg(OH)2, KCl, and Al2O3 in the salt mud, the amounts (mol) of Na, Ca, Mg, K, and Al in the salt mud can be determined. The formula is: Y Na / Ca / Mg / K / Al =C Na / Ca / Mg / K / Al，第二混合溶液 ×V 第二混合溶液 / (m0×X NaCl / CaCO3 / Mg(OH)2 / KCl / Al2O3 / M NaCl / CaCO3 / Mg(OH)2 / KCl / Al2O3 )×100%, Y Na / Ca / Mg / K / Al Na in salt mud + Ca 2 + Mg 2+ K + Al 3+ Extraction rate, %; C Na / Ca / Mg / K / Al，第二混合溶液 Na in the second mixed solution + Ca 2+ Mg 2+ K + Al 3+ Concentration, mol / L; V 第二混合溶液 The volume of the second mixed solution is L; m0 is the mass of salt mud on a dry basis, g; X CaCO3 / Mg(OH)2 / KCl / Al2O3 The content of CaCO3, Mg(OH)2, KCl, and Al2O3 in dry-based salt mud, in percentages (%). NaCl / CaCO3 / Mg(OH)2 / KCl / Al2O3 The relative molar mass of NaCl, CaCO3, Mg(OH)2, KCl, or Al2O3 is given in g / mol. Where X... CaCO3 It is 58.5%, X Mg(OH)2 It is 10.0%, X KCl It is 0.42%, X Al2O3 It is 1.0%, X NaCl The content is 19.5%, and m0 is 500g.

[0054] Na in the second mixed solution + Ca 2+ Mg 2+ K + Al 3+ The precipitation rate test is performed as follows: In step (4), the Na in the fourth mixed solution + Ca 2+ Mg 2+ K + Al3+ Concentration and volume, and thus the amount of Na, Ca, Mg, K, and Al remaining in the fourth mixed solution (mol); Na in the second mixed solution in step (3) + Ca 2+ Mg 2+ K + Al 3+ The concentration and volume are used to obtain the amount of Na, Ca, Mg, K, and Al in the second mixed solution (mol), which is the amount of Na, Ca, Mg, K, and Al before precipitation (mol). The formula is: X Na / Ca / Mg / K / Al =(C Na / Ca / Mg / K / Al，第二混合溶液 ×V 第二混合溶液 -C Na / Ca / Mg / K / Al，第四混合溶液 ×V 第四混合溶液 ) / (C Na / Ca / Mg / K / Alg，第二混合溶液 ×V 第二混合溶液 )×100%, X Na / Ca / Mg / K / Alg for Na + Ca 2+ Mg 2+ K + Al 3+ Extraction rate, %; C Na / Ca / Mg / K / Al，第二混合溶液 Na in the second mixed solution + Ca 2+ Mg 2+ K + Al 3+ Concentration, mol / L; V 第二混合溶液 The volume of the second mixed solution is L; C Na / Ca / Mg / K / Al，第四混合溶液 Na in the fourth mixed solution + Ca 2+ Mg 2+ K + Al 3+ Concentration, mol / L; V 第四混合溶液 Let L be the volume of the fourth mixed solution.

[0055] The yield test operation of the composite de-icing agent is as follows: the composite de-icing agent in step (5) is dried and weighed to obtain m2; the Na in the second mixture in step (3) + Ca 2+ Mg 2+ K + Al 3+ The amount of substance (mol) of the corresponding composite snow-melting agent is calculated from the concentration and volume, and then the theoretical mass (m) of the composite snow-melting agent is obtained. max The formula is: Y 复合型融雪剂 =m2 / m max ×100%, Y 复合型融雪剂The yield of the composite de-icing agent is %; m2 is the total mass of the composite de-icing agent, in g; m max Na in the second mixture + Ca 2+ Mg 2+ K + Al 3+ The total mass of the theoretically derived composite de-icing agent is expressed in grams.

[0056] Method for testing moisture in alcohol precipitation solution: First, clean the AKF-1 fully automatic Karl Fischer moisture analyzer with anhydrous methanol, then perform blank and drift correction, and finally calibrate with a mixed solution of deionized water and Karl Fischer reagent. Then add the sample to be tested, and the system automatically calculates the percentage of moisture content.

[0057]

[0058] Table 1 shows that the mass of the residue after drying is 55.75g. Calculations indicate that the utilization rate of the salt mud is 88.85%, and the extraction rate of the effective components from the salt mud reaches 99.27%. The Ca content in the second mixed solution... 2+ Na + K + Mg 2+ Al 3+ The concentrations were 1.66 mol / L, 0.94 mol / L, 0.016 mol / L, 0.46 mol / L, and 0.025 mol / L, respectively. Calculations showed that the effect on Ca in the salt mud... 2+ Na + K + Mg 2 + Al 3+ The extraction rates were 99.9%, 99.9%, 99.9%, 95.0%, and 90.0%, respectively; the Ca in the fourth mixed solution 2+ Na + K + Mg 2+ Al 3+ The concentrations were 1.04 mmol / L, 23.00 mmol / L, 0.49 mmol / L, 0.29 mmol / L, and 0.77 mmol / L, respectively. Calculations show that Ca... 2+ Na + K + Mg 2+ Al 3+The precipitation rates were 99.5%, 80.5%, 75.5%, 99.5%, and 75.5%, respectively; the mass of the composite snow-melting agent was 324.03 g, and the calculated product yield was 95.08%; the water content in the alcohol precipitation solution was 0.20%, and the reduction in water content facilitated the recycling of the alcohol precipitation solution, thus reducing the alcohol precipitation efficiency under the same conditions. In summary, the composite snow-melting agent contains Ca, Na, K, Mg, and Al elements, with Ca, Mg, and Na as the main elements and K and Al as trace elements.

[0059] Depend on Figure 1 It is known that the types of salts in the composite de-icing agent are related to the types of inorganic and organic acids in the acidification solution. The main components are calcium acetate, magnesium acetate, calcium chloride, magnesium chloride, sodium chloride, calcium formate, magnesium formate acetate and formate, and chloride salts, with trace amounts of potassium chloride and aluminum chloride present. This is consistent with the results of ICP testing. Therefore, the product obtained by this preparation method is a composite de-icing agent.

[0060] Depend on Figure 2 It can be seen that the composite de-icing agent has a blocky morphology. Example 2

[0061] (1) The solid phase in the salt mud was crushed into 100 mesh particles by a high-moisture vertical crusher. After crushing, the water content of the salt mud was detected by a solid content detector and found to be 50%. 1000g of crushed salt mud was weighed and then 500mL of pure water was added and mixed evenly to prepare a slurry. 10.0g of allyl alcohol polyoxyalkyl ether and 100g of 1-(2-aminoethyl)-2-methylpyrazole bromide were added to the slurry and mixed evenly to obtain the first mixed solution.

[0062] (2) Prepare an acidification solution by mixing 3.75 mol / L 37% concentrated hydrochloric acid and 3.75 mol / L glacial acetic acid. Add the acidification solution to the first mixed solution at a stirring speed of 200 r / min. React at 35°C for 2 h. After centrifugation, obtain the residue and the second mixed solution.

[0063] (3) Prepare an alcohol precipitation solution by mixing methanol, acetone and methyl acetate in a volume ratio of 2:1:1. Take 1000 mL of the second mixed solution and add 6000 mL of alcohol precipitation solution to the second mixed solution to carry out the alcohol precipitation reaction. Control the alcohol precipitation temperature at 5℃, the alcohol precipitation time at 1.0 h and the stirring rate at 800 r / min to obtain the third mixed solution.

[0064] (4) The third mixed solution is filtered and separated to obtain crude composite de-icing agent and fourth mixed solution. The crude composite de-icing agent is vacuum dried at 40℃ for 2.0h to obtain composite de-icing agent. The fourth mixed solution is distilled under reduced pressure in a distillation tower. A mixture of gaseous methanol, acetone, methyl acetate and water is obtained at the top. The mixture of gaseous methanol, acetone, methyl acetate and water is condensed to obtain fifth mixed solution. The reaction residue is obtained at the bottom of the distillation tower and is returned to step (1) as water for recycling.

[0065] (5) After mixing the fifth mixed solution with the 3A molecular sieve, the adsorption treatment is carried out. The amount of 3A molecular sieve added is controlled to be 3.0% of the mass of the fifth mixed solution, the adsorption time is 1.0 h, and the stirring speed is 200 r / min. After filtration and separation, the alcohol precipitation solution and the adsorbed 3A molecular sieve are obtained. The alcohol precipitation solution is returned to step (4) for recycling. The adsorbed 3A molecular sieve is vacuum dried at 100℃ for 3 h and then regenerated for recycling.

[0066] The residue in step (2) was dried and weighed. The weighing results are shown in Table 2.

[0067] In step (2), the second mixed solution is subjected to ICP Na + Ca 2+ Mg 2+ K + Al 3+ Concentration testing was conducted using the same method as in Example 1, and the results are shown in Table 2.

[0068] In step (4), the fourth mixed solution is subjected to ICP Na + Ca 2+ Mg 2+ K + Al 3+ Concentration testing was conducted using the same method as in Example 1, and the results are shown in Table 2.

[0069] In step (4), the yield and XRD structure of the composite de-icing agent were tested using the same methods as in Example 1. The test results are shown in Table 2. Figure 1 .

[0070] The moisture content of the alcohol precipitation solution in step (5) was tested using the same method as in Example 1, and the test results are shown in Table 2.

[0071]

[0072] Table 2 shows that the mass of the residue after drying is 65.25g. Calculations indicate that the utilization rate of the salt mud is 86.55%, and the extraction rate of the effective components from the salt mud reaches 96.70%. The Ca content in the second mixed solution... 2+ Na+ K + Mg 2+ Al 3+ The concentrations were 1.82 mol / L, 1.09 mol / L, 0.018 mol / L, 0.51 mol / L, and 0.027 mol / L, respectively. Calculations show that the concentrations of Ca in the salt mud... 2+ Na + K + Mg 2 + Al 3+ The extraction rates were 95.0%, 99.9%, 99.9%, 90.0%, and 85.0%, respectively; the Ca in the fourth mixed solution 2+ Na + K + Mg 2+ Al 3+ The concentrations were 11.70 mmol / L, 38.16 mmol / L, 0.72 mmol / L, 3.25 mmol / L, and 1.11 mmol / L, respectively. Calculations show that Ca... 2+ Na + K + Mg 2+ Al 3+ The precipitation rates were 95.5%, 75.5%, 72.5%, 95.5%, and 71.5%, respectively; the mass of the composite snow-melting agent was 340.23 g, and the calculated product yield was 90.80%; the water content in the alcohol precipitation solution was 0.5%, which facilitates the recycling of the alcohol precipitation solution under the same conditions, thus reducing the alcohol precipitation efficiency. In summary, the composite snow-melting agent contains Ca, Na, K, Mg, and Al elements, with Ca, Mg, and Na as the main elements and K and Al as trace elements.

[0073] Depend on Figure 1 It can be seen that the types of salts in the composite de-icing agent are related to the types of inorganic and organic acids in the acidification solution. The main components are calcium acetate, magnesium acetate, calcium chloride, magnesium chloride, acetate and chloride salts of sodium chloride, with trace amounts of potassium chloride and aluminum chloride present, which is consistent with the ICP detection results. Therefore, the product obtained by this preparation method is a composite de-icing agent. Example 3

[0074] (1) The solid phase in the salt mud was crushed into 200 mesh particles by a high-moisture vertical crusher. After crushing, the water content of the salt mud was measured to be 46% by a solid content detector. 781.25g of crushed salt mud was weighed and then 1640.625mL of pure water was added and mixed evenly to prepare a slurry. 10.0g of nonylphenol polyoxyethylene ether and 100g of tetrahedral ammonium bromide were added to the slurry and mixed evenly to obtain the first mixed solution.

[0075] (2) Prepare an acidification solution by mixing 2.5 mol of 37% concentrated hydrochloric acid and 7.5 mol of formic acid. Add the acidification solution to the first mixed solution at a stirring speed of 400 r / min. React at 55°C for 0.5 h. After centrifugation, obtain the residue and the second mixed solution.

[0076] (3) Prepare an alcohol precipitation solution by mixing methanol, ethyl ketone and ethyl acetate in a volume ratio of 4:1:4. Take 100 mL of the second mixed solution and add 1000 mL of the alcohol precipitation solution to the second mixed solution to carry out the alcohol precipitation reaction. Control the alcohol precipitation temperature at 49℃, the alcohol precipitation time at 0.5 h and the stirring rate at 500 r / min to obtain the third mixed solution.

[0077] (4) The third mixed solution is filtered and separated to obtain crude composite de-icing agent and fourth mixed solution. The crude composite de-icing agent is dried under vacuum at 60°C for 1.0 h to obtain composite de-icing agent. The fourth mixed solution is distilled under reduced pressure in a distillation tower. A mixture of gaseous methanol, ethyl ketone, ethyl acetate and water is obtained at the top. The mixture of gaseous methanol, ethyl ketone, ethyl acetate and water is condensed to obtain fifth mixed solution. The reaction residue is obtained at the bottom of the distillation tower and is returned to step (1) as water for recycling.

[0078] (5) After mixing the fifth mixed solution with the 3A molecular sieve, the adsorption treatment is carried out. The amount of 3A molecular sieve added is controlled to be 8.0% of the mass of the fifth mixed solution, the adsorption time is 0.5h, and the stirring speed is 300r / min. After filtration and separation, the alcohol precipitation solution and the adsorbed 3A molecular sieve are obtained. The alcohol precipitation solution is returned to step (4) for recycling. The adsorbed 3A molecular sieve is vacuum dried at 150℃ for 1h and regenerated for recycling.

[0079] In step (2), the residue was dried and weighed. The weighing results are shown in Table 3.

[0080] In step (2), the second mixed solution is subjected to ICP Na + Ca 2+ Mg 2+ K + Al 3+ Concentration testing was conducted using the same method as in Example 1, and the results are shown in Table 3.

[0081] In step (4), the fourth mixed solution is subjected to ICP Na + Ca 2+ Mg 2+ K + Al 3+ Concentration testing was conducted using the same method as in Example 1, and the results are shown in Table 3.

[0082] In step (4), the yield and XRD structure of the composite de-icing agent were tested using the same methods as in Example 1. The test results are shown in Table 3. Figure 1 .

[0083] The moisture content of the alcohol precipitation solution in step (5) was tested using the same method as in Example 1, and the test results are shown in Table 3.

[0084]

[0085] Table 3 shows that the mass of the residue after drying is 57.10 g. Calculations indicate that the utilization rate of the salt mud is 88.58%, and the extraction rate of the effective components from the salt mud reaches 98.97%. The Ca content in the second mixed solution... 2+ Na + K + Mg 2+ Al 3+ The concentrations were 1.17 mol / L, 0.67 mol / L, 0.011 mol / L, 0.29 mol / L, and 0.016 mol / L, respectively. Calculations show that the concentrations of Ca in the salt mud... 2+ Na + K + Mg 2 + Al 3+ The extraction rates were 99.9%, 99.9%, 99.9%, 85.5%, and 80.5%, respectively; the Ca in the fourth mixed solution 2+ Na + K + Mg 2+ Al 3+ The concentrations were 0.64 mmol / L, 12.27 mmol / L, 0.26 mmol / L, 0.19 mmol / L, and 0.36 mmol / L, respectively. Calculations show that Ca... 2+ Na + K + Mg 2+ Al 3+ The precipitation rates were 99.4%, 79.8%, 75.0%, 99.3%, and 74.8%, respectively. The mass of the composite snow-melting agent was 20.96 g, and the calculated product yield was 94.61%. The water content in the alcohol precipitation solution was 0.05%. The reduction in water content facilitates the recycling of the alcohol precipitation solution, thus reducing precipitation efficiency under the same conditions. In summary, the composite snow-melting agent contains Ca, Na, K, Mg, and Al elements, with Ca, Mg, and Na as the main elements and K and Al as trace elements.

[0086] Depend on Figure 1It can be seen that the types of salts in the composite de-icing agent are related to the types of inorganic and organic acids in the acidification solution. The main components are calcium formate, magnesium formate, calcium chloride, magnesium chloride, sodium chloride formate and chloride salts, with trace amounts of potassium chloride and aluminum chloride present, which is consistent with the ICP detection results. Therefore, the product obtained by this preparation method is a composite de-icing agent. Example 4

[0087] (1) The solid phase in the salt mud was crushed into 450 mesh particles by a high-moisture vertical crusher. After crushing, the moisture content of the salt mud was measured to be 20% by a solid content detector. 625g of crushed salt mud was weighed and then 1375mL of pure water was added and mixed evenly to prepare a slurry. 13.5g of allyl polyoxyalkyl epoxy ether and 120g of 1-propylamino-3-butylimidazolium tetrafluoroborate were added to the slurry and mixed evenly to obtain the first mixed solution.

[0088] (2) Prepare an acidification solution by mixing 1.75 mol of 37% concentrated hydrochloric acid, 1.2 mol of 68% concentrated nitric acid, 3 mol of glacial acetic acid and 2.8 mol of formic acid. Add the acidification solution to the first mixed solution at a stirring speed of 350 r / min. React at 40°C for 1.5 h. After centrifugation, obtain the residue and the second mixed solution. Discharge the residue.

[0089] (3) Prepare an alcohol precipitation solution by mixing methanol, ethyl ketone and methyl acetate in a volume ratio of 3.5:1:3.5. Take 100 mL of the second mixed solution and add 800 mL of alcohol precipitation solution to the second mixed solution to carry out the alcohol precipitation reaction. Control the alcohol precipitation temperature at 20℃, the alcohol precipitation time at 1.0 h and the stirring rate at 550 r / min to obtain the third mixed solution.

[0090] (4) The third mixed solution is filtered and separated to obtain crude composite de-icing agent and fourth mixed solution. The crude composite de-icing agent is vacuum dried at 60℃ for 1.0h to obtain composite de-icing agent. The fourth mixed solution is distilled under reduced pressure in a distillation tower. A mixture of gaseous methanol, ethyl ketone, methyl acetate and water is obtained at the top. The mixture of gaseous methanol, ethyl ketone, methyl acetate and water is condensed to obtain the fifth mixed solution. The reaction residue is obtained at the bottom of the distillation tower and is returned to step (1) as water for recycling.

[0091] (5) After mixing the fifth mixed solution with the 3A molecular sieve, the adsorption treatment is carried out. The amount of 3A molecular sieve added is controlled to be 6.0% of the mass of the fifth mixed solution, the adsorption time is 0.7h, and the stirring speed is 200r / min. After filtration and separation, the alcohol precipitation solution and the adsorbed 3A molecular sieve are obtained. The alcohol precipitation solution is returned to step (4) for recycling. The adsorbed 3A molecular sieve is vacuum dried at 110℃ for 3h and then regenerated for recycling.

[0092] In step (2), the residue was dried and weighed. The weighing results are shown in Table 4.

[0093] In step (2), the second mixed solution is subjected to ICP Na + Ca 2+ Mg 2+ K + Al 3+ Concentration testing was conducted using the same method as in Example 1, and the results are shown in Table 4.

[0094] In step (4), the fourth mixed solution is subjected to ICP Na + Ca 2+ Mg 2+ K + Al 3+ Concentration testing was conducted using the same method as in Example 1, and the results are shown in Table 4.

[0095] In step (4), the yield of the composite de-icing agent was tested using the same method as in Example 1. The test results are shown in Table 4.

[0096] The moisture content of the alcohol precipitation solution in step (5) was tested using the same method as in Example 1. The test results are shown in Table 4.

[0097]

[0098] Table 4 shows that the mass of the residue after drying is 57.25g. Calculations indicate that the utilization rate of the salt mud is 88.55%, and the extraction rate of the effective components from the salt mud reaches 98.94%. The Ca content in the second mixed solution... 2+ Na + K + Mg 2+ Al 3+ The concentrations were 1.46 mol / L, 0.83 mol / L, 0.014 mol / L, 0.40 mol / L, and 0.022 mol / L, respectively. Calculations showed that the effect on Ca in the salt mud... 2+ Na + K + Mg 2 + Al 3+ The extraction rates were 99.9%, 99.9%, 99.9%, 93.5%, and 88.5%, respectively; the Ca in the fourth mixed solution 2+ Na + K + Mg 2+ Al 3+The concentrations were 1.30 mmol / L, 18.39 mmol / L, 0.40 mmol / L, 0.27 mmol / L, and 0.60 mmol / L, respectively. Calculations show that Ca... 2+ Na + K + Mg 2+ Al 3+ The precipitation rates were 99.2%, 80.1%, 74.6%, 99.4%, and 75.0%, respectively. The mass of the composite de-icing agent was 29.28 g, and the calculated product yield was 94.88%. The water content in the alcohol precipitation solution was 0.15%, which facilitates the recycling of the alcohol precipitation solution under the same conditions, thus reducing the alcohol precipitation efficiency. In summary, the composite de-icing agent contains Ca, Na, K, Mg, and Al elements, with Ca, Mg, and Na as the main elements and K and Al as trace elements. The composition of this composite de-icing agent is related to the types of organic and inorganic acids in the acidification solution, and mainly consists of formate, nitrate, acetate, and chloride salts. Example 5

[0099] (1) The solid phase in the salt mud was crushed into 500 mesh particles by a high-moisture vertical pulverizer. After crushing, the moisture content of the salt mud was measured to be 20% by a solid content detector. 625g of crushed salt mud was weighed and then 975mL of pure water was added and mixed evenly to prepare a slurry. 10.45g of allyl alcohol polyoxyalkyl ether and 104.5g of 1-(2-aminoethyl)-2-methylpyrazole bromide were added to the slurry and mixed evenly to obtain the first mixed solution.

[0100] (2) Prepare an acidification solution by mixing 2.5 mol of 68% concentrated nitric acid and 5.25 mol of glacial acetic acid. Add the acidification solution to the first mixed solution at a stirring speed of 400 r / min. React at 40°C for 1.8 h. After filtration, obtain the residue and the second mixed solution.

[0101] (3) Prepare an alcohol precipitation solution by mixing ethanol, acetone and ethyl acetate in a volume ratio of 2.5:1:1.5. Take 100 mL of the second mixed solution and add 650 mL of alcohol precipitation solution to the second mixed solution to carry out the alcohol precipitation reaction. Control the alcohol precipitation temperature at 10℃, the alcohol precipitation time at 1.0 h and the stirring rate at 750 r / min to obtain the third mixed solution.

[0102] (4) The third mixed solution is filtered and separated to obtain crude composite de-icing agent and fourth mixed solution. The crude composite de-icing agent is vacuum dried at 45°C for 1.5h to obtain composite de-icing agent. The fourth mixed solution is distilled under reduced pressure in a distillation tower. A mixture of gaseous ethanol, acetone, ethyl acetate and water is obtained at the top. The mixture of gaseous ethanol, acetone, ethyl acetate and water is condensed to obtain fifth mixed solution. The reaction residue is obtained at the bottom of the distillation tower and is returned to step (1) as water for recycling.

[0103] (5) After mixing the fifth mixed solution with the 3A molecular sieve, the adsorption treatment is carried out. The amount of 3A molecular sieve added is controlled to be 3.5% of the mass of the fifth mixed solution, the adsorption time is 0.7h, and the stirring speed is 250r / min. After filtration and separation, the alcohol precipitation solution and the adsorbed 3A molecular sieve are obtained. The alcohol precipitation solution is returned to step (4) for recycling. The adsorbed 3A molecular sieve is vacuum dried at 140℃ for 2.5h and then regenerated for recycling.

[0104] In step (2), the residue was dried and weighed. The weighing results are shown in Table 5.

[0105] In step (2), the second mixed solution is subjected to ICP Na + Ca 2+ Mg 2+ K + Al 3+ Concentration testing was conducted using the same method as in Example 1, and the results are shown in Table 5.

[0106] In step (4), the fourth mixed solution is subjected to ICP Na + Ca 2+ Mg 2+ K + Al 3+ Concentration testing was conducted using the same method as in Example 1, and the results are shown in Table 5.

[0107] In step (4), the yield of the composite de-icing agent was tested using the same method as in Example 1. The test results are shown in Table 5.

[0108] The moisture content of the alcohol precipitation solution in step (5) was tested using the same method as in Example 1, and the test results are shown in Table 5.

[0109]

[0110] Table 5 shows that the mass of the residue after drying is 66.37 g. Calculations indicate that the utilization rate of the salt mud is 86.73%, and the extraction rate of the effective components from the salt mud reaches 96.90%. The Ca content in the second mixed solution... 2+ Na + K +Mg 2+ Al 3+ The concentrations were 1.79 mol / L, 1.06 mol / L, 0.018 mol / L, 0.50 mol / L, and 0.027 mol / L, respectively. Calculations show that the concentrations of Ca in the salt mud... 2+ Na + K + Mg 2 + Al 3+ The extraction rates were 95.5%, 99.9%, 99.9%, 90.5%, and 87.5%, respectively; the Ca in the fourth mixed solution 2+ Na + K + Mg 2+ Al 3+ The concentrations were 8.33 mmol / L, 33.77 mmol / L, 0.63 mmol / L, 2.11 mmol / L, and 1.00 mmol / L, respectively. Calculations show that Ca... 2+ Na + K + Mg 2+ Al 3+ The precipitation rates were 96.5%, 76.2%, 73.8%, 96.8%, and 72.6%, respectively. The mass of the composite de-icing agent was 39.35 g, and the calculated product yield was 92.27%. The water content in the alcohol precipitation solution was 0.45%, which facilitates the recycling of the alcohol precipitation solution under the same conditions, thus reducing the alcohol precipitation efficiency. In summary, the composite de-icing agent contains Ca, Na, K, Mg, and Al elements, with Ca, Mg, and Na as the main elements and K and Al as trace elements. The composition of this composite de-icing agent is related to the types of organic and inorganic acids in the acidification solution, and mainly consists of nitrates, acetates, and sodium chloride. Comparative Example 1

[0111] The difference between Comparative Example 1 and Example 1 is that the salt mud was not crushed in step (1), while the other steps remained the same.

[0112] In step (2), the residue was dried and weighed. The weighing results are shown in Table 6.

[0113] In step (2), the second mixed solution is subjected to ICP Na + Ca 2+ Mg 2+ K + Al 3+ Concentration testing was conducted using the same method as in Example 1, and the results are shown in Table 6.

[0114] In step (4), the fourth mixed solution is subjected to ICP Na + Ca 2+ Mg 2+ K + Al 3+ Concentration testing was conducted using the same method as in Example 1, and the results are shown in Table 6.

[0115] In step (4), the yield of the composite de-icing agent was tested using the same method as in Example 1. The test results are shown in Table 6.

[0116]

[0117] Table 6 shows that the mass of the residue after drying is 282.10 g. Calculations show that the utilization rate of the salt mud is 43.58%, and the extraction rate of the effective components from the salt mud reaches 48.69%. The Ca content in the second mixed solution... 2+ Na + K + Mg 2+ Al 3+ The concentrations were 0.76 mol / L, 0.57 mol / L, 0.0084 mol / L, 0.21 mol / L, and 0.011 mol / L, respectively. Calculations show that the effect on Ca in the salt mud... 2+ Na + K + Mg 2+ Al 3+ The extraction rates were 45.9%, 52.5%, 59.9%, 43.9%, and 38.9%, respectively; the Ca in the fourth mixed solution 2+ Na + K + Mg 2+ Al 3+ The concentrations were 22.92 mmol / L, 27.93 mmol / L, 0.42 mmol / L, 7.25 mmol / L, and 0.56 mmol / L, respectively. Calculations show that Ca... 2+ Na + K + Mg 2+ Al 3+ The precipitation rates were 75.9%, 60.5%, 59.8%, 72.8%, and 58.9%, respectively; the mass of the composite de-icing agent was 117.31 g, and the calculated product yield was 71.35%. In summary, under the same conditions, if the salt mud is not crushed, it will affect the utilization rate of the salt mud, the extraction rate of the effective components in the salt mud, and the yield of the composite de-icing agent. Therefore, the salt mud needs to be crushed. Comparative Example 2

[0118] The difference between Comparative Example 2 and Example 1 is that the amount of water used in step (1) is different. 1125 mL of pure water is replaced with 375 mL of pure water, while the other steps remain the same.

[0119] During the experiment, it was found that when the ratio of dry-balanced salt mud to water was less than 1g:2mL, after adding the acidifying solution, the reaction lasted for about 5 minutes, after which the entire reaction system became a viscous solid agglomerate, making the acidification reaction impossible. The reason for the formation of this viscous solid agglomerate state is that the acidifying solutions of hydrochloric acid, formic acid, and glacial acetic acid react violently with the calcium carbonate in the salt mud, generating a large amount of heat and carbon dioxide bubbles. This heat carries away some water, and the calcium chloride and other substances produced in the reaction absorb water, resulting in a high solid content in the entire reaction system. Because of the low water content, the viscosity of the bubbles further increases, causing them to combine with the salt mud to form viscous solid agglomerates, making the acidification reaction impossible and reducing the utilization rate of the salt mud to zero. Therefore, controlling the amount of water used is a crucial factor in determining whether the acidification reaction can proceed; an appropriate amount of water must be used. Comparative Example 3

[0120] The difference between Comparative Example 3 and Example 1 is that the acidification aid allyl polyoxyalkyl epoxy ether was not added in step (1), while the other steps remained the same.

[0121] During the experiment, it was found that without the addition of an acidifying agent, the acidification reaction was violent, producing large bubbles of carbon dioxide gas that caused salt mud and solution to overflow, posing a danger to the reaction. Therefore, the acidifying agent is a key factor in ensuring the safe and mild conduct of the acidification reaction, and it has a synergistic effect with ionic liquids. Comparative Example 4

[0122] The difference between Comparative Example 4 and Example 1 is that the acidification aid allyl polyoxyalkyl epoxy ether and the ionic liquid 1-propylamino-3-butylimidazolium tetrafluoroborate were not added in step (1), while the other operation steps remained unchanged.

[0123] During the experiment, it was found that without the addition of acidifying agents and ionic liquids, the reactants in the reactor became viscous solid agglomerates after a single addition of the acidifying solution. This is because the acetic acid, hydrochloric acid, and formic acid in the acidifying solution react violently with calcium carbonate in the salt mud, generating a large amount of heat and carbon dioxide bubbles. This heat carries away some water, and the calcium acetate, calcium chloride, calcium formate, magnesium chloride, magnesium acetate, and magnesium formate produced in the reaction absorb water, resulting in a high solid content in the entire reaction system. Because of the low water content, the viscosity of the bubbles further increases, causing them to combine with the salt mud to form viscous solid agglomerates, preventing the acidification reaction from proceeding. Therefore, ionic liquids and acidifying agents are necessary prerequisites for the acidification reaction to take place. Comparative Example 5

[0124] The difference between Comparative Example 5 and Example 1 is that the 93.75g of ionic liquid 1-propylamino-3-butylimidazolium tetrafluoroborate in step (1) is replaced with 93.75g of pure water and the acidification solution in step (2) is added dropwise, while the other operation steps remain unchanged.

[0125] In step (2), the residue was dried and weighed. The weighing results are shown in Table 7.

[0126] In step (2), the second mixed solution is subjected to ICP Na + Ca 2+ Mg 2+ K + Al 3+ Concentration testing was conducted using the same method as in Example 1, and the results are shown in Table 7.

[0127] In step (4), the fourth mixed solution is subjected to ICP Na + Ca 2+ Mg 2+ K + Al 3+ Concentration testing was conducted using the same method as in Example 1, and the results are shown in Table 7.

[0128] In step (4), the yield of the composite de-icing agent was tested using the same method as in Example 1. The test results are shown in Table 7.

[0129]

[0130] Table 7 shows that the mass of the dried residue is 56.00 g. Calculations indicate that the utilization rate of the salt mud is 88.80%, and the extraction rate of the effective components from the salt mud reaches 99.22%. The Ca content in the second mixed solution... 2+ Na + K + Mg 2+ Al 3+ The concentrations were 1.66 mol / L, 0.94 mol / L, 0.016 mol / L, 0.46 mol / L, and 0.025 mol / L, respectively. Calculations showed that the effect on Ca in the salt mud... 2+ Na + K + Mg 2 + Al 3+ The extraction rates were 99.9%, 99.9%, 99.9%, 95.0%, and 90.0%, respectively; the Ca in the fourth mixed solution 2+ Na + K + Mg 2+ Al 3+The concentrations were 30.01 mmol / L, 28.90 mmol / L, 0.55 mmol / L, 9.52 mmol / L, and 1.08 mmol / L, respectively. Calculations show that Ca... 2+ Na + K + Mg 2+ Al 3+ The precipitation rates were 85.5%, 75.5%, 72.5%, 83.5%, and 65.5%, respectively; the mass of the composite de-icing agent was 280.92 g, and the yield was 82.43%. Compared with Example 1, it can be seen that ionic liquids can affect the addition rate of the acidification solution. This is because during the acidification reaction, ionic liquids possess amino or azole functional groups (i.e., nitrogen sites) that can absorb carbon dioxide in situ, reducing the possibility of large bubbles being generated; ionic liquids also affect the reaction rate with Ca. 2+ Na + K + Mg 2+ Al 3+ The precipitation rate, and consequently the yield of the composite de-icing agent, is affected by the presence of ionic liquids during the alcohol precipitation process, which lowers the Ca2+ concentration in the reaction solution. 2+ Na + K + Mg 2+ Al 3+ The solubility of [the substance] increases the efficiency of alcohol precipitation. Comparative Example 6

[0131] The difference between Comparative Example 6 and Example 1 is that the inorganic acid 37% concentrated hydrochloric acid in step (2) is replaced with the organic acid glacial acetic acid, while the other operation steps remain unchanged.

[0132] In step (2), the residue was dried, weighed, and the utilization rate of salt mud and the extraction rate of effective components in salt mud were tested. The test method was the same as in Example 1.

[0133] The weight of the dried residue was 95.75g. Calculations showed that the utilization rate of the salt mud was 80.85%, and the utilization rate of the effective components in the salt mud was 90.33%. Compared with Example 1, it can be seen that under the same conditions, without the addition of inorganic acids, the acidification effect of organic acids on salt mud was lower than that of inorganic acids and organic acids. Comparative Example 7

[0134] The difference between Comparative Example 7 and Example 1 is that the organic acid in step (2) is replaced with 37% concentrated hydrochloric acid, while the other operation steps remain unchanged. Comparative Example 8

[0135] Commercial anhydrous calcium chloride, calcium formate, magnesium chloride, magnesium acetate, magnesium formate, sodium chloride, potassium chloride, aluminum chloride, aluminum formate, and aluminum acetate were blended in amounts of 0.975 mol, 1.25 mol, 0.696 mol, 0.286 mol, 0.367 mol, 0.204 mol, 1.67 mol, 0.028 mol, 0.0163 mol, 0.021 mol, and 0.0117 mol, respectively, to obtain a composite de-icing agent. Comparative Example 9

[0136] The difference between Comparative Example 9 and Example 1 is that the alcohol precipitation reaction conditions in step (3) are different. The alcohol precipitation temperature is changed from 25°C to 80°C, while the other operation steps remain unchanged.

[0137] During the alcohol precipitation reaction, it was found that when the precipitation temperature exceeded 50°C, the reaction solution rapidly transformed into a gel state. This is because at excessively high temperatures, the de-icing agent in the solution quickly nucleates, grows, and precipitates out. The particles also adhere to each other, causing the solution to gel, making the material difficult to remove and thus hindering industrial production. Therefore, it is crucial to appropriately control the temperature of the alcohol precipitation reaction. Comparative Example 10

[0138] The difference between Comparative Example 10 and Example 1 is that the alcohol precipitation reaction conditions in step (3) are different. The stirring speed is changed from 500 r / min to 100 r / min, while the other operation steps remain unchanged.

[0139] During the alcohol precipitation reaction, it was found that when the stirring speed was below 500 r / min, the reaction solution rapidly turned into a gel state. This is because the excessively low stirring speed caused the particles to rapidly nucleate, grow, and adhere to each other, resulting in a gel-like state in the solution. This made the material difficult to remove, thus hindering industrial-scale production. Therefore, it is crucial to appropriately control the stirring speed of the alcohol precipitation reaction.

[0140] Test Example 1

[0141] Solutions with a concentration of 200 g / L were prepared for Examples 1-5, Comparative Examples 6-7, sodium chloride, and calcium chloride dihydrate. 75 mL of the above 200 g / L solutions were tested for freezing point using an automatic freezing point tester (Shandong Shengtai Instrument Co., Ltd., model: SH128). The test results are shown in Table 8.

[0142]

[0143] As shown in Table 8, the freezing points of the composite de-icing agents in Examples 1-5 range from -18.2 to -24.8°C, while the freezing points of Comparative Example 6 are -9.8°C, Comparative Example 7 is -12.7°C, sodium chloride is -13.2°C, and calcium chloride dihydrate is -13.7°C. In summary, this composite de-icing agent can be used in de-icing and ice-melting environments ranging from -15°C to -20°C. This indicates that the de-icing agent prepared from an acidified solution composed of pure inorganic or organic acids has a significantly higher freezing point than the acidified solution composed of inorganic and organic acids. This is due to the interaction of different salts and is far superior to the freezing points of single acetate, chloride, or formate salts.

[0144] The solid dissolution rate of Examples 1-5, Comparative Example 8, sodium chloride, and calcium chloride dihydrate was tested using the same method as in GB / T 2351-2017 De-icing Agents. The test results are shown in Table 9.

[0145]

[0146] As shown in Table 9, the composite de-icing agents prepared in Examples 1-5 have a dissolution rate 1.17-1.38 times that of the de-icing agent obtained by blending in Example 8, which far exceeds the level specified by national standards, demonstrating excellent solid dissolution performance. This is because the density, particle shape, and size of each salt are different, and simple mixing can easily lead to uneven mixing, resulting in different dissolution rates. However, the alcohol precipitation method of this invention can precipitate a composite de-icing agent with uniform particles in situ, thereby greatly accelerating the dissolution rate.

[0147] In summary, a comparison between Comparative Example 1 and Example 1 shows that a salt mud particle size of 100-500 mesh is a key condition for the acidification reaction. A comparison between Comparative Example 2 and Example 1 shows that the amount of pure water used is a crucial factor determining whether the acidification reaction can proceed; the ratio of salt mud mass to water on a dry basis must be appropriately controlled. A comparison between Comparative Examples 3-4 and Example 1 shows that the acidification aid and ionic liquid work together to suppress the generation of large carbon dioxide bubbles, exhibiting a synergistic effect and jointly inhibiting the solution from becoming a viscous solid agglomerate, which is a necessary prerequisite for maintaining a mild acidification reaction. A comparison between Comparative Example 5 and Example 1 shows that the ionic liquid can absorb carbon dioxide, reducing the likelihood of large bubbles appearing, and has a synergistic effect with the acidification aid, promoting the one-time addition of the acidification liquid and accelerating the acidification reaction process; simultaneously, the ionic liquid also affects the absorption of Ca... 2+ Na + K + Mg 2+ Al 3+The precipitation rate is crucial; therefore, ionic liquids are an essential condition for the entire reaction process. A comparison between Comparative Example 6 and Example 1 shows that, under the same conditions, without the addition of inorganic acids, the acidification effect of organic acids on salt mud is lower than that of inorganic and organic acids. A comparison between Comparative Example 8 and Example 1 shows that the solid dissolution rate of the composite de-icing agent obtained by simple blending is much lower than that obtained by alcohol precipitation. This is because the density, particle shape, and size of each salt are different, leading to uneven mixing and thus different dissolution rates. A comparison between Comparative Examples 9-10 and Example 1 shows that the alcohol precipitation temperature and stirring speed both affect the alcohol precipitation effect; therefore, it is necessary to appropriately control the alcohol precipitation reaction conditions. Furthermore, the freezing point of de-icing agents prepared from acidification solutions composed of pure inorganic or organic acids is much higher than that of acidification solutions composed of both inorganic and organic acids. This is due to the interaction between different salts, and is far superior to the freezing point of a single acetate, chloride, or formate. Another advantage of acidification solutions prepared from inorganic and organic acids is that inorganic acids are cheaper than organic acids, which can reduce the cost of material preparation.

Claims

1. A method for preparing a composite de-icing agent through comprehensive utilization of chlor-alkali salt sludge solid waste, characterized in that, Includes the following steps: (1) The solid phase in the salt mud is crushed into 100-500 mesh particles, and then mixed with water to form a slurry. The ratio of the mass of salt mud to water in the slurry on a dry basis is controlled to be 1g:2-4mL. Then, acidification aid and ionic liquid are added to the slurry to obtain the first mixed solution. (2) Prepare an acidification solution by mixing inorganic acid and organic acid. Add the acidification solution to the first mixed solution at one time while stirring. React at 35-55℃ for 0.5-2h. After separation, obtain the residue and the second mixed solution. (3) Mix water-soluble alcohol organic solvents, ketone organic solvents and ester organic solvents to prepare an alcohol precipitation solution, add the alcohol precipitation solution to the second mixed solution to carry out the alcohol precipitation reaction, and obtain a third mixed solution; (4) The third mixed solution is separated to obtain crude composite de-icing agent and fourth mixed solution; the crude composite de-icing agent is dried to obtain composite de-icing agent; the fourth mixed solution is distilled under reduced pressure to obtain a gaseous mixture of water-soluble alcohol organic solvent, ketone organic solvent, ester organic solvent and water at the top; the mixture of water-soluble alcohol organic solvent, ketone organic solvent, ester organic solvent and water is condensed to obtain fifth mixed solution; the bottom is the reaction residue, which is recycled. (5) Add 3A molecular sieve to the fifth mixed solution for adsorption, and then separate the solution to obtain alcohol precipitation solution and adsorbed 3A molecular sieve. Return the alcohol precipitation solution to step (4) for recycling and reuse. The adsorbed 3A molecular sieve is regenerated and reused. In step (1), the acidifying agent is one of allyl polyoxyalkyl epoxy ether, allyl alcohol polyoxyalkyl ether, or nonylphenol polyoxyethylene ether; the ionic liquid is one of 1-propylamino-3-butylimidazolium tetrafluoroborate, 1-(2-aminoethyl)-2-methylpyrazole bromide, or tetrahedral ammonium bromide. In step (3), the alcohol precipitation reaction conditions are: alcohol precipitation temperature 5-49℃, alcohol precipitation time 0.5-1h, and stirring speed 500-800r / min.

2. The method for preparing a composite de-icing agent through comprehensive utilization of chlor-alkali salt sludge solid waste according to claim 1, characterized in that, In step (1), the ratio of the amount of acidifying agent added to the total amount of water in the first mixed solution is 0.005-0.01g:1mL; the ratio of the amount of ionic liquid added to the total amount of water in the first mixed solution is 0.05-0.1g:1mL.

3. The method for preparing a composite de-icing agent through comprehensive utilization of chlor-alkali salt sludge solid waste according to claim 1, characterized in that, In step (2), the inorganic acid is one or two of concentrated hydrochloric acid and nitric acid; the organic acid is one or two of acetic acid and formic acid; the ratio of inorganic acid to organic acid in the acidification solution is 1 mol: 1-3 mol.

4. The method for preparing a composite de-icing agent through comprehensive utilization of chlor-alkali salt sludge solid waste according to claim 1, characterized in that, In step (2), the stirring speed is 200-400 r / min; the mass ratio of acidified liquid to salt mud in the first mixed solution on a dry basis is 0.015-0.020 mol: 1 g.

5. The method for preparing a composite de-icing agent through comprehensive utilization of chlor-alkali salt sludge solid waste according to claim 1, characterized in that, In step (3), the water-soluble alcohol organic solvent is one of methanol or ethanol; the ketone organic solvent is one of acetone or ethyl ketone; and the ester organic solvent is one of ethyl acetate or methyl acetate. In step (3), the volume ratio of water-soluble alcohol organic solvents to ketone organic solvents and ester organic solvents in the alcohol precipitation solution is 2-4:1:1-4; the volume ratio of the amount of alcohol precipitation solution added to the volume ratio of the second mixed solution is 6-10:

1.

6. The method for preparing a composite de-icing agent through comprehensive utilization of chlor-alkali salt sludge solid waste according to claim 1, characterized in that, In step (4), the drying conditions are: vacuum drying at 40-60℃ and vacuum drying time of 1-2h; the reaction residue is recycled and reused by returning the reaction residue to step (1) to be used as water.

7. The method for preparing a composite de-icing agent through comprehensive utilization of chlor-alkali salt sludge solid waste according to claim 1, characterized in that, In step (5), the adsorption conditions are as follows: the amount of 3A molecular sieve added is 3-8% of the mass of the fifth mixed solution, the adsorption time is 0.5-1h, and the stirring speed is 200-300r / min.

8. The method for preparing a composite de-icing agent through comprehensive utilization of chlor-alkali salt sludge solid waste according to claim 1, characterized in that, In step (5), the conditions for regenerating and reusing the adsorbed 3A molecular sieve are: vacuum drying temperature 100-150℃ and vacuum drying time 1-3h.

9. The application of a composite de-icing agent prepared by the method described in any one of claims 1-8, characterized in that, It is used as a snow-melting agent in snow and ice melting at temperatures ranging from -15°C to -20°C.

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