Method for preparing calcium magnesium acetate environment-friendly snow-melting corrosion inhibitor by comprehensive utilization of chlor-alkali salt mud solid waste

Abstract

The invention provides a method for preparing a calcium magnesium acetate environment-friendly snow melting corrosion inhibitor by comprehensive utilization of chlor-alkali salt mud solid waste, and belongs to the technical field of solid waste resource comprehensive utilization and organic material synthesis. The method comprises the following steps: firstly, preparing chlor-alkali salt mud and water into slurry, then adding acetic acid at one time under the action of an acidification auxiliary agent and an ionic liquid, and then realizing the precipitation of the calcium magnesium acetate environment-friendly snow melting corrosion inhibitor in an alcohol precipitation solution. According to the method, the utilization rate of the salty mud reaches 84.13-87.26%, the extraction rates of Ca < 2 + > and Mg < 2 + > in the salty mud respectively reach 95-99.99% and 85-92%, total recovery of high-value components in the salty mud is basically achieved, the precipitation rates of Ca < 2 + > and Mg < 2 + > in the solution respectively reach 96.4-99.9% and 96.6-99.9%, total precipitation of Ca < 2 + > and Mg < 2 + > is basically achieved, the product yield reaches 96.5-99.9%, the product whiteness reaches 98.0 or above, no waste liquid is generated in the whole process, and the method is suitable for industrial production. The cyclic utilization of the salty mud solid waste is realized.

Description

Technical Field

[0001] The invention belongs to the technical field of comprehensive utilization of solid waste resources and organic material synthesis, and particularly relates to a method for preparing an environmentally friendly calcium magnesium acetate snow-melting corrosion inhibitor by comprehensive utilization of chlor-alkali salt mud solid waste. Background Art

[0002] Salt mud is a byproduct of brine refining in the chlor-alkali industry. Every ton of caustic soda produced generates 50-60 kg of solid salt mud. China's chlor-alkali production capacity is approximately 50 million tons per year, generating approximately 2.5-3 million tons of salt mud annually. As a general industrial solid waste, improper handling of salt mud can not only negatively impact the ecological environment and human well-being, but also pose a significant challenge to businesses.

[0003] Shandong Haihua's chlor-alkali facility has an annual production capacity of 300,000 tons. The main components of dry-base salt sludge are 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%). The remainder is insoluble matter (approximately 10.5%, primarily CaSO₄ and SiO₂). Currently, most salt sludge in the chlor-alkali industry, both domestically and internationally, is still disposed of in landfills. The implementation of the new standards will increase investment in salt sludge treatment for chlor-alkali companies and will also tighten landfill acceptance requirements. Therefore, the efficient and comprehensive utilization of chlor-alkali salt sludge, particularly the recovery of calcium and magnesium elements, has become a hot topic for researchers both domestically and internationally.

[0004] Calcium magnesium acetate (CMA), a mixture of calcium acetate and magnesium acetate, is a new, environmentally friendly de-icing agent. Compared to existing chloride-based de-icing agents, which are used in over 90% of applications, CMA offers advantages such as low corrosivity, biodegradability, and minimal harm to plants. However, the existing CMA process, which uses oxides and acetic acid as raw materials and precipitates calcium magnesium acetate through evaporation, concentration, and crystallization, suffers from high raw material costs and energy consumption, limiting its widespread use and adoption to specialized locations such as airports and highways. Furthermore, when using low-cost solid wastes with high calcium and magnesium content, such as salt sludge, phosphate tailings, or dolomite, as raw materials, the resulting solution exhibits a reddish-brown color due to the presence of iron. Traditionally, adsorbents have been added to remove iron impurities to meet the national whiteness standard for de-icing agents (GB / T 23851-2017). However, this requires additional steps such as adsorption, impurity removal, and adsorbent regeneration, increasing operating costs. Therefore, developing an inexpensive production process for CMA is crucial for promoting and popularizing this environmentally friendly de-icing and corrosion inhibitor. Currently, there is no method for preparing calcium magnesium acetate environmentally friendly snow-melting corrosion inhibitor that does not require evaporation and crystallization.

[0005] Currently, the comprehensive utilization method for producing deicing agents from chlor-alkali salt sludge waste involves preparing the sludge with water to form a slurry, which is then acidified with an acetic acid acidifier. Evaporation and concentration are then performed to produce a highly concentrated calcium-magnesium solution. Corrosion inhibitors are then added, mixed, spray-dried, and granulated to produce the deicing agent. During the acidification process, researchers attempt to minimize the risk of overflow by adding acetic acid or increasing the reactor volume. This approach reduces the risk of overflow caused by the vigorous reaction between acetic acid and salt sludge, which produces large amounts of carbon dioxide. However, this increases the total acidification reaction time and reduces the reactor volume utilization. Alternatively, researchers attempt to control the rate of carbon dioxide generation by reducing the instantaneous concentration of the acetic acid acidifier—in other words, by increasing the liquid-to-solid ratio of water to salt sludge in the slurry—to mitigate the risk of deicing. However, the addition of large amounts of water reduces the calcium and magnesium concentrations in the reaction system, further increasing the evaporation and concentration process costs and resulting in poor economic returns. Therefore, rapid deicing agent preparation methods that achieve high salt sludge utilization, high-concentration calcium-magnesium solutions, and low costs are of great interest to companies and researchers.

[0006] Chinese invention patent publication number CN119039133A discloses calcium magnesium acetate prepared from phosphate tailings, its preparation method, and application. The method involves calcining the phosphate tailings at high temperature to obtain an oxide, then adding an aqueous solution containing acetic acid. The solution is reacted at room temperature for 15-40 minutes to obtain a calcium magnesium acetate solution, which is then evaporated, concentrated, and crystallized to obtain calcium magnesium acetate. See description in the specification 0095 section of this patent, the extraction rate of calcium and magnesium reaches 94.24%, 95.53% at most, namely in the calcium-magnesium acetate solution, calcium ion and magnesium ion concentration are respectively 0.069-0.16moL / L, 0.042-0.097moL / L, the calcium-magnesium acetate solution concentration obtained is lower, this is because this patent has increased the consumption of aqueous solvent in order to improve the extraction rate of calcium and magnesium in the phosphate tailings, but has sacrificed the concentration of solution, therefore, when calcium-magnesium acetate solution carries out evaporation, concentration and crystallization, energy consumption is huge. In addition, it is also necessary to carry out high-temperature calcination to the precursor of the phosphate tailings, this is because this patent has changed oxide by carbonate in order to reduce the consumption and the reaction times of acetic acid, and the reaction rate of acetic acid and oxide is faster than carbonate, but has increased energy consumption, which is uneconomical.

[0007] Chinese invention patent publication number CN106497517A discloses a method for preparing an environmentally friendly organic de-icing agent using salt sludge using a two-alkali process. This method involves preparing a slurry of salt sludge and water, then adding an organic acid. The mixture is filtered, concentrated by evaporation under reduced pressure, spray-dried, and then granulated on two rollers to produce an environmentally friendly de-icing agent made of calcium magnesium acetate. Because the salt sludge slurry contains a large amount of calcium carbonate, and the reaction system requires the addition of an excess of organic acid, the reaction between the organic acid and calcium carbonate produces a large amount of carbon dioxide bubbles, posing a risk of overflow. To mitigate this risk, researchers added the organic acid slowly, but this significantly prolonged the reaction time and reduced production efficiency. Because the salt sludge contains impurities such as iron, the solution appears yellow or reddish-brown. The lack of an adsorbent-free impurity removal process results in a reduced whiteness of the environmentally friendly calcium magnesium acetate de-icing agent, failing to meet the national standard for de-icing agent whiteness (GB / T 23851-2017). Furthermore, the patent does not address the utilization rate of the salt sludge, merely describing the performance of the environmentally friendly calcium magnesium acetate de-icing agent. Summary of the Invention

[0008] The technical problem to be solved by this invention is to provide a method for comprehensively utilizing chlor-alkali salt sludge solid waste to prepare an environmentally friendly calcium magnesium acetate snow-melting corrosion inhibitor. This method solves the problems of prolonged acidifying agent addition time and low volume utilization of the acidification reactor during salt sludge acidification. It also addresses the long preparation time, high energy consumption, and low whiteness of traditional processes for preparing environmentally friendly calcium magnesium acetate snow-melting corrosion inhibitors. Furthermore, it achieves value-added utilization of salt sludge, reduces emissions, and transforms waste into valuable resources, effectively promoting the healthy development of the chlor-alkali industry and presenting broad prospects for industrial application.

[0009] To solve the above problems, the technical solution of the present invention is a method for preparing an environmentally friendly snow-melting corrosion inhibitor of calcium magnesium acetate by comprehensive utilization of chlor-alkali salt mud solid waste, comprising the following steps: (1) The solid phase in the salt mud is crushed into 200-500 mesh particles, and then mixed with water to form a slurry, and the ratio of the mass of the salt mud to water in the slurry on a dry basis is controlled to be 1g:2-4mL, and then an acidifying agent and an ionic liquid are added to the slurry to obtain a first mixed solution; (2) Adding acetic acid to the first mixed solution at once under stirring, reacting at 25-85°C for 1-4 hours, and separating to obtain a residue and a second mixed solution; (3) mixing a water-soluble alcohol organic solvent with a ketone organic solvent or an ester organic solvent to prepare an alcohol precipitation solution, adding the alcohol precipitation solution to the second mixed solution to carry out an alcohol precipitation reaction, and obtaining a third mixed solution; (4) The third mixed solution is separated to obtain a crude calcium magnesium acetate environmentally friendly snow-melting corrosion inhibitor and a fourth mixed solution; the crude calcium magnesium acetate environmentally friendly snow-melting corrosion inhibitor is dried to obtain a calcium magnesium acetate environmentally friendly snow-melting corrosion inhibitor; the fourth mixed solution is subjected to reduced pressure distillation to obtain a gaseous mixture of a water-soluble alcohol organic solvent, a ketone organic solvent or an ester organic solvent, and water at the top, and the gaseous mixture of the water-soluble alcohol organic solvent, the ketone organic solvent or the ester organic solvent, and water is condensed to obtain a fifth mixed solution; a reaction residue is obtained at the bottom, and the reaction residue is recycled; (5) 3A molecular sieve is added to the fifth mixed solution for adsorption, and then separated to obtain an alcohol precipitation solution and the adsorbed 3A molecular sieve. The alcohol precipitation solution is returned to step (4) for recycling, and the adsorbed 3A molecular sieve is regenerated and reused.

[0010] Furthermore, in the step (1), the acidifying aid is one of allyl polyoxyalkyl epoxy ether, allyl alcohol polyoxyalkyl ether, or nonylphenol polyoxyethylene ether; and the ionic liquid is one of 1-propylamino-3-butylimidazole tetrafluoroborate, 1-(2-aminoethyl)-2-methylpyrazole bromide, or tetra-n-heptyl ammonium bromide.

[0011] Furthermore, in step (1), the ratio of the amount of the acidifying agent added to the total amount of water in the first mixed solution is 0.003-0.008 g:1 mL; the ratio of the amount of the ionic liquid added to the total amount of water in the first mixed solution is 0.1-0.15 g:1 mL.

[0012] Furthermore, in the step (2), the stirring speed is 100-300 r / min; and the mass ratio of acetic acid to the salt mud in the first mixed solution on a dry basis is 0.016-0.019 mol:1 g.

[0013] Furthermore, in step (3), the alcohol organic solvent is one of methanol or ethanol; the ketone organic solvent is one of acetone or ethylketone; and the ester organic solvent is one of ethyl acetate or methyl acetate.

[0014] Furthermore, in step (3), the volume ratio of the alcohol organic solvent to the ketone organic solvent or the ester organic solvent in the alcohol precipitation solution is 1:2-4; and the volume ratio of the added amount of the alcohol precipitation solution to the second mixed solution is 1-5:1.

[0015] Furthermore, in step (3), the alcohol precipitation reaction conditions are: alcohol precipitation temperature 30-60°C, alcohol precipitation time 0.5-1h, and stirring speed 300-600r / min.

[0016] Furthermore, in step (4), the drying conditions are: vacuum drying at 40-60°C and vacuum drying time of 1-2 hours; the reaction residue is recycled by returning the reaction residue to step (1) to serve as water.

[0017] Furthermore, in step (5), the adsorption conditions are as follows: the amount of 3A molecular sieve added is 2-5% of the mass of the fifth mixed solution, the adsorption time is 0.5-1 h, and the stirring speed is 200-300 r / min.

[0018] Furthermore, in step (5), the adsorbed 3A molecular sieve is regenerated and recycled under the following conditions: vacuum drying temperature of 100-150°C and vacuum drying time of 1-3h.

[0019] The beneficial effects of the present invention are: (1) The present invention helps to promote the process of acidification reaction by crushing the solid phase in the salt mud into fine particles of 200-500 mesh, thereby improving the utilization rate of the salt mud and the extraction rate of the effective components in the salt mud.

[0020] (2) The present invention can not only save reaction time but also prevent solution overflow by adding ionic liquid and acidifying agent. Among them, ionic liquid has three functions: first, it improves the dispersibility of salt mud and reduces the surface tension of the solution; second, it has the function of in-situ absorption of carbon dioxide gas generated during the acidification reaction, thereby reducing the risk of solidification of the reaction solution and working together with the acidifying agent; third, it improves Ca 2+ Mg 2+ In addition, the acidification agent disperses large carbon dioxide bubbles into small bubbles, which are easier to break during the stirring reaction. This synergistically works with the ionic liquid's ability to adsorb carbon dioxide bubbles in situ, optimizing the acidification reaction. This eliminates the need to control the acetic acid addition rate and allows for direct, all-in-one addition of acetic acid, laying the foundation for industrial continuous operation.

[0021] (3) The present invention optimizes the amount of water added, reaction temperature, reaction time, and acetic acid added, thereby ensuring a high concentration of calcium and magnesium solution while achieving high utilization of salt mud and extraction of effective components from the salt mud. The utilization rate of salt mud reaches 84.13-87.26%, and the extraction rate of effective components from salt mud reaches 94-97.50%, especially for Ca 2+ Mg 2+ The extraction rates are 95-99.99% and 85-92% respectively, for Ca 2+ and Mg 2+ High-value components are basically fully recycled, and only a part of the residue is discharged during the whole process, which reduces the emission of salt mud and contributes to the healthy development of the chlor-alkali industry.

[0022] (4) The alcohol precipitation method of the present invention does not involve chemical reactions. It only optimizes the volume ratio of water-soluble alcohol organic solvents to ketone organic solvents or 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 adjust the Ca content in the solution. 2+ Mg 2+ The precipitation rates reached 96.4-99.9% and 96.6-99.9% respectively, basically achieving Ca 2+ and Mg 2+ The product yield reaches 96.5-99.9%, and the product whiteness reaches above 98.0. This method is 15 times faster than direct evaporation and concentration to prepare environmentally friendly snow-melting corrosion inhibitor of calcium magnesium acetate, and 1.09 times brighter than the product directly concentrated and crystallized. At the same time, due to the use of organic solvent alcohol to precipitate the environmentally friendly snow-melting corrosion inhibitor of calcium magnesium acetate, the drying conditions of the environmentally friendly snow-melting corrosion inhibitor of calcium magnesium acetate are reduced, and energy consumption is reduced. In addition, the selected water-soluble alcohol organic solvents and ketone organic solvents or ester organic solvents have low boiling points and low costs, are easy to distill and recycle, and reduce the cost of process operation.

[0023] (5) The 3A molecular sieve in the present invention can adsorb water in the alcohol precipitation solution. By optimizing the amount of 3A molecular sieve added to adsorb water, the moisture content is reduced to below 0.5%, which helps to recycle the alcohol precipitation solution and reduces the process operation cost. At the same time, the 3A molecular sieve can be repeatedly regenerated after drying, realizing a circular economy.

[0024] (6) The present invention achieves efficient and full utilization of resources, wherein 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 the salt sludge, achieving zero discharge of waste liquid, greatly reducing production costs, and having significant environmental and economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The X-ray diffraction (XRD) structure diagram of the environmentally friendly snow-melting corrosion inhibitor of calcium magnesium acetate obtained in step (4) of Example 1-5; Figure 2 This is a scanning electron microscope (SEM) morphology of the calcium magnesium acetate environmentally friendly snow-melting corrosion inhibitor obtained in step (4) of Example 1. DETAILED DESCRIPTION

[0026] The present invention will be described in detail below with reference to the embodiments and drawings, but the protection scope of the present invention is not limited thereto.

[0027] In a specific embodiment of the present invention, the high-humidity material vertical crusher used is composed of a motor, a screen, a crushing knife, and a frame. Among them, the high-humidity material vertical crusher model is LPS500, the brand is Xinruiheng, the output voltage is 380V, and the power is 11Kw. The solid content detector used is composed of a weighing module, a heating module, and a control system. Among them, the solid content detector model is GSY-G3, the brand is Shenfen Instrument, the output voltage is 220V, the weighing range is 0-70g, and the moisture measurement range is 0.01-100%. Example 1

[0028] (1) The solid phase in the salt mud is crushed into 500 mesh particles by a high-humidity material vertical crusher. The water content of the crushed salt mud is 20% as measured by a solid content detector. 625 g of the crushed salt mud is weighed, and then 1125 mL of pure water is added and mixed evenly to prepare a slurry. 6.25 g of allyl polyoxyalkyl epoxy ether and 162.5 g of 1-propylamino-3-butyl imidazole tetrafluoroborate are added to the slurry and mixed evenly to obtain a first mixed solution; (2) Add 8.5 mol glacial acetic acid to the first mixed solution at a stirring speed of 200 r / min, react at 60°C for 3 h, and separate by suction filtration to obtain a residue and a second mixed solution; (3) Methanol and acetone were prepared into an alcohol precipitation solution in a volume ratio of 1:3, 100 mL of the second mixed solution was taken, and 400 mL of the alcohol precipitation solution was added to the second mixed solution to carry out an alcohol precipitation reaction, and the alcohol precipitation temperature was controlled to be 45°C, the alcohol precipitation time was controlled to be 0.8 h, and the stirring rate was controlled to be 450 r / min to obtain a third mixed solution; (4) The third mixed solution is separated by filtration to obtain a crude product of calcium magnesium acetate environmentally friendly snow-melting corrosion inhibitor and a fourth mixed solution. The crude product of calcium magnesium acetate environmentally friendly snow-melting corrosion inhibitor is vacuum dried at 50° C. for 1.5 h to obtain calcium magnesium acetate environmentally friendly snow-melting corrosion inhibitor; the fourth mixed solution is subjected to reduced pressure distillation in a distillation tower to obtain a gaseous mixture of methanol, acetone, and water at the top, and the gaseous mixture of methanol, acetone, and water is condensed to obtain a fifth mixed solution; a reaction residue is obtained at the bottom of the distillation tower, and the reaction residue is returned to step (1) as water for recycling; (5) The fifth mixed solution is mixed with 3A molecular sieve and then subjected to adsorption treatment, wherein 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 0.8 h, and the stirring speed is 200 r / min. The alcohol precipitation solution and the adsorbed 3A molecular sieve are obtained by filtration and separation; the alcohol precipitation solution is returned to step (4) for recycling; the adsorbed 3A molecular sieve is vacuum dried at 120° C. for 2 h, and then regenerated and recycled.

[0029] The residue in step (2) was dried and weighed. The weighing results are shown in Table 1. In step (2), the second mixed solution was subjected to inductively coupled plasma spectrometry (ICP) Ca 2+ Mg 2+ Concentration test, test results are shown in Table 1.

[0030] In step (4), the fourth mixed solution is subjected to ICP Ca 2+ Mg 2+ Concentration test, test results are shown in Table 1.

[0031] In step (4), the environmentally friendly snow-melting corrosion inhibitor of calcium magnesium acetate was subjected to X-ray diffraction (XRD) structure, scanning electron microscope (SEM) morphology, yield and whiteness tests. The test results are shown in Figure 1 、 Figure 2 , Table 1, Table 1.

[0032] The water content of the alcohol precipitation solution in step (5) was tested, and the test results are shown in Table 1.

[0033] The test operation of salt mud utilization is as follows: weigh the residue after drying, and calculate the formula: Y 总 =(m0-m1) / m0×100%,Y 总 is the salt mud utilization rate, %; m0 is the mass of salt mud on a dry basis, g; m1 is the mass of the residue after drying, g. Among them, m0 is 500g.

[0034] The test operation of the effective ingredient extraction rate in salt mud is as follows: weigh the mass of the residue after drying, and calculate the formula: Y 有效 = (m0-m1) / (m0×(1-X 酸性不溶物 ))×100%,Y 有效 is the extraction rate of effective components in salt mud, %; m0 is the mass of salt mud on dry basis, g; X 酸性不溶物 is the content of acidic insoluble matter in dry salt mud, %; m1 is the mass of the residue after drying, g. 酸性不溶物 SiO2 and CaSO4 in dry salt mud are 10.5% in total, and m0 is 500g.

[0035] ICP Ca 2+ and Mg 2+ Concentration test method: Prepare standard curves of calcium acetate solution or magnesium acetate solution with different concentrations using calcium acetate and magnesium acetate respectively with deionized water. The average error is ≥0.999. The Ca concentration of the test sample is obtained according to the standard curves of calcium acetate solution and magnesium acetate solution. 2+ concentration and Mg 2+ concentration.

[0036] Ca in salt mud 2+ Mg 2+The extraction rate test operation is as follows: the Ca content of the second mixed solution in step (2) is 2+ Mg 2+ The concentration and volume can be used to obtain the amount of Ca and Mg remaining in the fourth mixed solution (moL); take 625g of salt mud, and the mass fractions of CaCO3 and Mg(OH)2 in the dry salt mud are known, and the amount of Ca and Mg in the salt mud (moL) can be obtained. The formula is: Y Ca / Mg =C Ca或Mg，第二混合溶液 ×V 第二混合溶液 / (m0×X CaCO3 / Mg（OH）2 / M CaCO3 / Mg(OH)2 )×100%, Y Ca / Mg Ca in salt mud 2+ Mg 2+ Extraction rate,%;C Ca或Mg，第二混合溶液 is the Ca in the second mixed solution 2+ Mg 2+ Concentration, moL / L; V 第二混合溶液 is the volume of the second mixed solution, L; m0 is the mass of the salt mud on a dry basis, g; X CaCO3 / Mg(OH)2 is the content of CaCO3 and Mg(OH)2 in dry salt mud, %; M CaCO3 / Mg（OH）2 is the relative molar mass of CaCO3 or Mg(OH)2, g / moL. CaCO3 is 58.5%, X Mg(OH)2 is 10.0%, m0 is 500g.

[0037] Ca in the second mixed solution 2+ Mg 2+ The precipitation rate test operation is as follows: the Ca content of the fourth mixed solution in step (4) is 2 + Mg 2+ The concentration and volume of the fourth mixed solution are used to obtain the amount of Ca and Mg remaining in the fourth mixed solution (moL); the Ca content of the second mixed solution in step (3) is 2+ Mg 2+ The concentration and volume are used to obtain the amount (moL) of Ca and Mg in the second mixed solution, that is, the amount (moL) of Ca and Mg before precipitation. The formula is: X Ca或Mg =(C Ca或Mg，第二混合溶液 ×V 第二混合溶液 -C Ca或Mg，第四混合溶液 ×V 第四混合溶液 ) / (C Ca或Mg，第二混合溶液 ×V 第二混合溶液 )×100%,X Ca或Mg Ca 2+ Mg 2+ Precipitation rate, %; C Ca或Mg，第二混合溶液 is the Ca in the second mixed solution2+ Mg 2+ Concentration, moL / L; V 第二混合溶液 is the volume of the second mixed solution, L; C Ca或Mg，第四混合溶液 is the Ca in the fourth mixed solution 2+ Mg 2+ Concentration, moL / L; V 第四混合溶液 is the volume of the fourth mixed solution, L.

[0038] The yield test of the environmentally friendly snow-melting corrosion inhibitor of calcium magnesium acetate is as follows: the environmentally friendly snow-melting corrosion inhibitor of calcium magnesium acetate in step (5) is dried and weighed to obtain m2; the Ca content of the second mixed solution in step (3) is 2+ Mg 2+ The amount of substance (moL) of the corresponding calcium magnesium acetate environmentally friendly snow-melting corrosion inhibitor was calculated by concentration and volume, and then the theoretical mass of the calcium magnesium acetate environmentally friendly snow-melting corrosion inhibitor (m max ), the formula is: Y 融雪缓蚀剂 =m2 / m max ×100%,Y 融雪缓蚀剂 is the yield of calcium magnesium acetate environmentally friendly snow-melting corrosion inhibitor, %; m2 is the total mass of calcium magnesium acetate environmentally friendly snow-melting corrosion inhibitor, g; m max is the Ca in the second mixed solution 2+ Mg 2+ Theoretically, all of it is converted into the mass of calcium magnesium acetate environmentally friendly snow-melting corrosion inhibitor, g.

[0039] 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 corrections, 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 moisture content percentage.

[0040] Whiteness test method of environmentally friendly calcium magnesium acetate snow-melting corrosion inhibitor: First, preheat the WSB-3C fluorescent whiteness tester for more than 15 seconds, then adjust to zero, and then place the calibration reference white plate on the sample holder for calibration. The error range of multiple calibrations is ±0.1. Finally, place the sample to be tested on the sample holder for reading.

[0041] As shown in Table 1, the mass of the residue after drying is 65.925 g. Calculation shows that the utilization rate of salt mud is 86.82%, and the extraction rate of effective components in salt mud reaches 97.0%. 2+ Mg 2+ The concentrations are 1.50moL / L and 0.40moL / L respectively. It can be calculated that the Ca 2+ Mg 2+ The extraction rates were 99.9% and 90.0% respectively; the Ca 2+Mg 2+ The concentrations are 1.88mmoL / L and 0.50mmoL / L respectively. It can be calculated that Ca 2+ Mg 2+ The precipitation rates are 99.5% and 99.5% respectively; the mass of the environmentally friendly snow-melting corrosion inhibitor of calcium magnesium acetate is 29.28g. After calculation, it can be seen that the product yield is 99.5%; the whiteness of the environmentally friendly snow-melting corrosion inhibitor of calcium magnesium acetate is 98.5; the water content in the alcohol precipitation solution is 0.3%.

[0042] Depend on Figure 1 It can be seen that the environmentally friendly calcium magnesium acetate snow-melting corrosion inhibitor contains diffraction peaks of calcium acetate and magnesium acetate. Therefore, the product obtained by this preparation method is calcium magnesium acetate.

[0043] Depend on Figure 2 It can be seen that the morphology of the environmentally friendly calcium magnesium acetate snow-melting corrosion inhibitor is tubular. Example 2

[0044] (1) The solid phase in the salt mud is crushed into 400 mesh particles by a high-humidity material vertical crusher. The water content of the crushed salt mud is 20% as measured by a solid content detector. 625 g of the crushed salt mud is weighed, and then 875 mL of pure water is added and mixed evenly to prepare a slurry. 8.0 g of allyl alcohol polyoxyalkyl ether and 150 g of 1-(2-aminoethyl)-2-methylpyrazole bromide are added to the slurry and mixed evenly to obtain a first mixed solution; (2) Add 8.0 mol glacial acetic acid to the first mixed solution at a stirring speed of 100 r / min, react at 25°C for 4 h, and separate by suction filtration to obtain a residue and a second mixed solution; (3) Methanol and acetone were prepared into an alcohol precipitation solution in a volume ratio of 1:2, 100 mL of the second mixed solution was taken, and 100 mL of the alcohol precipitation solution was added to the second mixed solution to carry out an alcohol precipitation reaction, and the alcohol precipitation temperature was controlled to be 60°C, the alcohol precipitation time was controlled to be 0.5 h, and the stirring rate was controlled to be 600 r / min to obtain a third mixed solution; (4) The third mixed solution is separated by filtration to obtain a crude product of calcium magnesium acetate environmentally friendly snow-melting corrosion inhibitor and a fourth mixed solution. The crude product of calcium magnesium acetate environmentally friendly snow-melting corrosion inhibitor is vacuum dried at 40° C. for 2.0 h to obtain calcium magnesium acetate environmentally friendly snow-melting corrosion inhibitor; the fourth mixed solution is subjected to reduced pressure distillation in a distillation tower to obtain a gaseous mixture of methanol, acetone, and water at the top, and the gaseous mixture of methanol, acetone, and water is condensed to obtain a fifth mixed solution; a reaction residue is obtained at the bottom of the distillation tower, and the reaction residue is returned to step (1) as water for recycling; (5) The fifth mixed solution is mixed with 3A molecular sieve and then subjected to adsorption treatment, wherein the amount of 3A molecular sieve added is controlled to be 2.0% of the mass of the fifth mixed solution, the adsorption time is 1.0 h, and the stirring speed is 300 r / min. The mixture is separated by filtration to obtain an alcohol precipitation solution and the adsorbed 3A molecular sieve; the alcohol precipitation solution is returned to step (4) for recycling; the adsorbed 3A molecular sieve is vacuum dried at 100° C. for 3 h, and then regenerated and recycled.

[0045] The residue in step (2) was dried and weighed. The weighing results are shown in Table 1. In step (2), the second mixed solution is subjected to ICP Ca 2+ Mg 2+ Concentration test: the test method is the same as in Example 1, and the test results are shown in Table 1.

[0046] In step (4), the fourth mixed solution is subjected to ICP Ca 2+ Mg 2+ Concentration test: the test method is the same as in Example 1, and the test results are shown in Table 1.

[0047] In step (4), the calcium magnesium acetate environmentally friendly snow melting corrosion inhibitor was tested for XRD structure, yield and whiteness. The test method was the same as in Example 1. The test results are shown in Table 1. Figure 1 , Table 1, Table 1.

[0048] As shown in Table 1, the mass of the residue after drying is 79.350 g. Calculation shows that the utilization rate of salt mud is 84.13%, and the extraction rate of effective components in salt mud reaches 94.0%. 2+ Mg 2+ The concentrations are 1.68moL / L and 0.44moL / L respectively. It can be calculated that the Ca 2+ Mg 2+ The extraction rates were 95.0% and 85.0% respectively; the Ca 2+ Mg 2+ The concentrations are 30.24mmoL / L and 7.48mmoL / L respectively. It can be calculated that Ca 2+ Mg 2+ The precipitation rates are 96.4% and 96.6% respectively; the mass of the environmentally friendly snow-melting corrosion inhibitor of calcium magnesium acetate is 31.69 g. After calculation, it can be seen that the product yield is 96.5%; the whiteness of the environmentally friendly snow-melting corrosion inhibitor of calcium magnesium acetate is 98.0; the water content in the alcohol precipitation solution is 0.5%.

[0049] Depend on Figure 1 It can be seen that the environmentally friendly calcium magnesium acetate snow-melting corrosion inhibitor contains diffraction peaks of calcium acetate and magnesium acetate. Therefore, the product obtained by this preparation method is calcium magnesium acetate. Example 3

[0050] (1) The solid phase in the salt mud was crushed into 200 mesh particles by a high-humidity material vertical crusher. The water content of the crushed salt mud was 46% as measured by a solid content detector. 781.25 g of the crushed salt mud was weighed, and then 1640.625 mL of pure water was added and mixed evenly to prepare a slurry. 6.0 g of nonylphenol polyoxyethylene ether and 200 g of tetra-n-heptyl ammonium bromide were added to the slurry and mixed evenly to obtain a first mixed solution. (2) Add 9.5 mol glacial acetic acid to the first mixed solution at a stirring speed of 300 r / min, react at 85°C for 1 h, and centrifuge to obtain a residue and a second mixed solution; (3) Methanol and ethyl acetate were prepared into an alcohol precipitation solution in a volume ratio of 1:4. 100 mL of the second mixed solution was taken, and 500 mL of the alcohol precipitation solution was added to the second mixed solution to carry out an alcohol precipitation reaction. The alcohol precipitation temperature was controlled to be 30°C, the alcohol precipitation time was controlled to be 1.0 h, and the stirring rate was controlled to be 300 r / min to obtain a third mixed solution. (4) The third mixed solution is centrifuged to obtain a crude calcium magnesium acetate environmentally friendly snow-melting corrosion inhibitor and a fourth mixed solution. The crude calcium magnesium acetate environmentally friendly snow-melting corrosion inhibitor is vacuum-dried at 60° C. for 1.0 h to obtain the calcium magnesium acetate environmentally friendly snow-melting corrosion inhibitor. The fourth mixed solution is subjected to reduced pressure distillation in a distillation tower to obtain a gaseous mixture of methanol, ethyl acetate, and water at the top. The gaseous mixture of methanol, ethyl acetate, and water is condensed to obtain a fifth mixed solution. A reaction residue is obtained at the bottom of the distillation tower, and the reaction residue is returned to step (1) as water for recycling. (5) The fifth mixed solution is mixed with 3A molecular sieve and then subjected to adsorption treatment, wherein the amount of 3A molecular sieve added is controlled to be 5.0% of the mass of the fifth mixed solution, the adsorption time is 0.5 h, and the stirring speed is 250 r / min. The alcohol precipitation solution and the adsorbed 3A molecular sieve are obtained by filtration and separation; the alcohol precipitation solution is returned to step (4) for recycling; the adsorbed 3A molecular sieve is vacuum dried at 150° C. for 1 h, and then regenerated and recycled.

[0051] The residue in step (2) was dried and weighed. The weighing results are shown in Table 1. In step (2), the second mixed solution is subjected to ICP Ca 2+ Mg 2+ Concentration test: the test method is the same as in Example 1, and the test results are shown in Table 1.

[0052] In step (4), the fourth mixed solution is subjected to ICP Ca 2+ Mg 2+ Concentration test: the test method is the same as in Example 1, and the test results are shown in Table 1.

[0053] In step (4), the calcium magnesium acetate environmentally friendly snow melting corrosion inhibitor was tested for XRD structure, yield and whiteness. The test method was the same as in Example 1. The test results are shown in Table 1. Figure 1 , Table 1, Table 1.

[0054] As shown in Table 1, the mass of the residue after drying is 63.688 g. Calculation shows that the utilization rate of salt mud is 87.26%, and the extraction rate of effective components in salt mud reaches 97.5%. 2+ Mg 2+ The concentrations are 1.05moL / L and 0.28moL / L respectively. It can be calculated that the Ca 2+ Mg 2+ The extraction rates were 99.99% and 92.0% respectively; the Ca 2+ Mg 2+ The concentrations are 0.175mmoL / L and 0.047mmoL / L respectively. It can be calculated that Ca 2+ Mg 2+ The precipitation rates are 99.9% and 99.9% respectively; the mass of the environmentally friendly snow-melting corrosion inhibitor of calcium magnesium acetate is 20.58g. After calculation, it can be seen that the product yield is 99.9%; the whiteness of the environmentally friendly snow-melting corrosion inhibitor of calcium magnesium acetate is 98.5; the water content in the alcohol precipitation solution is 0.05%.

[0055] Depend on Figure 1 It can be seen that the environmentally friendly calcium magnesium acetate snow-melting corrosion inhibitor contains diffraction peaks of calcium acetate and magnesium acetate. Therefore, the product obtained by this preparation method is calcium magnesium acetate. Example 4

[0056] (1) The solid phase in the salt mud is crushed into 450 mesh particles by a high-humidity material vertical crusher. The water content of the crushed salt mud is 20% by a solid content detector. 625 g of the crushed salt mud is weighed, and then 1625 mL of pure water is added and mixed evenly to prepare a slurry. 7.0 g of allyl polyoxyalkyl epoxy ether and 210 g of 1-propylamino-3-butyl imidazole tetrafluoroborate are added to the slurry and mixed evenly to obtain a first mixed solution; (2) Add 9.0 mol glacial acetic acid to the first mixed solution at a stirring speed of 300 r / min, react at 75°C for 2 h, and centrifuge to obtain a residue and a second mixed solution; (3) Methanol and methyl acetate were prepared into an alcohol precipitation solution in a volume ratio of 1:3.5. 100 mL of the second mixed solution was taken, and 400 mL of the alcohol precipitation solution was added to the second mixed solution to carry out an alcohol precipitation reaction. The alcohol precipitation temperature was controlled to be 40°C, the alcohol precipitation time was controlled to be 0.6 h, and the stirring rate was controlled to be 400 r / min to obtain a third mixed solution. (4) The third mixed solution is centrifuged to obtain a crude calcium magnesium acetate environmentally friendly snow-melting corrosion inhibitor and a fourth mixed solution. The crude calcium magnesium acetate environmentally friendly snow-melting corrosion inhibitor is vacuum dried at 55° C. for 1.0 h to obtain calcium magnesium acetate environmentally friendly snow-melting corrosion inhibitor. The fourth mixed solution is subjected to reduced pressure distillation in a distillation tower to obtain a gaseous mixture of methanol, methyl acetate, and water at the top. The gaseous mixture of methanol, methyl acetate, and water is condensed to obtain a fifth mixed solution. A reaction residue is obtained at the bottom of the distillation tower, and the reaction residue is returned to step (1) as water for recycling. (5) The fifth mixed solution is mixed with 3A molecular sieve and then subjected to adsorption treatment, wherein the amount of 3A molecular sieve added is controlled to be 4.0% of the mass of the fifth mixed solution, the adsorption time is 0.8 h, and the stirring speed is 200 r / min. After filtration, an 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° C. for 3 h, and then regenerated and recycled.

[0057] The residue in step (2) was dried and weighed. The weighing results are shown in Table 1. In step (2), the second mixed solution is subjected to ICP Ca 2+ Mg 2+ Concentration test: the test method is the same as in Example 1, and the test results are shown in Table 1.

[0058] In step (4), the fourth mixed solution is subjected to ICP Ca 2+ Mg 2+ Concentration test: the test method is the same as in Example 1, and the test results are shown in Table 1.

[0059] In step (4), the calcium magnesium acetate environmentally friendly snow melting corrosion inhibitor was tested for XRD structure, yield and whiteness. The test method was the same as in Example 1. The test results are shown in Table 1. Figure 1 , Table 1, Table 1.

[0060] As shown in Table 1, the mass of the residue after drying is 66.82 g. Calculation shows that the utilization rate of salt mud is 86.64%, and the extraction rate of effective components in salt mud reaches 96.8%. 2+ Mg 2+ The concentrations are 1.16 moL / L and 0.30 moL / L respectively. It can be calculated that the Ca 2+ Mg 2+ The extraction rates were 99.99% and 89.0% respectively; the Ca 2+ Mg 2+ The concentrations are 1.39mmoL / L and 0.24mmoL / L respectively. It can be calculated that Ca 2+ Mg 2+The precipitation rates are 99.4% and 99.6% respectively; the mass of the environmentally friendly snow-melting corrosion inhibitor of calcium magnesium acetate is 22.51g. After calculation, it can be seen that the product yield is 99.50%; the whiteness of the environmentally friendly snow-melting corrosion inhibitor of calcium magnesium acetate is 98.5; the water content in the alcohol precipitation solution is 0.15%.

[0061] Depend on Figure 1 It can be seen that the environmentally friendly calcium magnesium acetate snow-melting corrosion inhibitor contains diffraction peaks of calcium acetate and magnesium acetate. Therefore, the product obtained by this preparation method is calcium magnesium acetate. Example 5

[0062] (1) The solid phase in the salt mud is crushed into 500 mesh particles by a high-humidity material vertical crusher. The water content of the crushed salt mud is 20% as measured by a solid content detector. 625 g of the crushed salt mud is weighed, and then 1125 mL of pure water is added and mixed evenly to prepare a slurry. 7.5 g of allyl alcohol polyoxyalkyl ether and 150 g of 1-(2-aminoethyl)-2-methylpyrazole bromide are added to the slurry and mixed evenly to obtain a first mixed solution; (2) Add 9.0 mol glacial acetic acid to the first mixed solution at a stirring speed of 250 r / min, react at 65°C for 3 h, and centrifuge to obtain a residue and a second mixed solution; (3) Ethanol and acetone were prepared into an alcohol precipitation solution in a volume ratio of 1:4, 100 mL of the second mixed solution was taken, and 200 mL of the alcohol precipitation solution was added to the second mixed solution to carry out an alcohol precipitation reaction, and the alcohol precipitation temperature was controlled to be 50°C, the alcohol precipitation time was controlled to be 1.0 h, and the stirring rate was controlled to be 500 r / min to obtain a third mixed solution; (4) The third mixed solution is centrifuged to obtain a crude calcium magnesium acetate environmentally friendly snow-melting corrosion inhibitor and a fourth mixed solution. The crude calcium magnesium acetate environmentally friendly snow-melting corrosion inhibitor is vacuum-dried at 45° C. for 1.5 h to obtain a calcium magnesium acetate environmentally friendly snow-melting corrosion inhibitor. The fourth mixed solution is subjected to reduced pressure distillation in a distillation tower to obtain a gaseous mixture of ethanol, acetone, and water at the top. The gaseous mixture of ethanol, acetone, and water is condensed to obtain a fifth mixed solution. A reaction residue is obtained at the bottom of the distillation tower, and the reaction residue is returned to step (1) as water for recycling. (5) The fifth mixed solution was mixed with 3A molecular sieve and then subjected to adsorption treatment, wherein the amount of 3A molecular sieve added was controlled to be 4.5% of the mass of the fifth mixed solution, the adsorption time was 0.8 h, and the stirring speed was 300 r / min. After filtration and separation, an alcohol precipitation solution and the adsorbed 3A molecular sieve were obtained; the alcohol precipitation solution was returned to step (4) for recycling; the adsorbed 3A molecular sieve was vacuum dried at 140° C. for 3 h, and then regenerated and recycled.

[0063] The residue in step (2) was dried and weighed. The weighing results are shown in Table 1. In step (2), the second mixed solution is subjected to ICP Ca 2+ Mg 2+ Concentration test: the test method is the same as in Example 1, and the test results are shown in Table 1.

[0064] In step (4), the fourth mixed solution is subjected to ICP Ca 2+ Mg 2+ Concentration test: the test method is the same as in Example 1, and the test results are shown in Table 1.

[0065] In step (4), the calcium magnesium acetate environmentally friendly snow melting corrosion inhibitor was tested for XRD structure, yield and whiteness. The test method was the same as in Example 1. The test results are shown in Table 1. Figure 1 , Table 1, Table 1.

[0066] As shown in Table 1, the mass of the residue after drying is 66.37 g. Calculation shows that the utilization rate of salt mud is 86.73%, and the extraction rate of effective components in salt mud reaches 96.9%. 2+ Mg 2+ The concentrations are 1.49moL / L and 0.39moL / L respectively. It can be calculated that the Ca 2+ Mg 2+ The extraction rates were 99.99% and 89.0% respectively; the Ca 2+ Mg 2+ The concentrations are 9.93mmoL / L and 0.91mmoL / L respectively. It can be calculated that Ca 2+ Mg 2+ The precipitation rates are 98.0% and 99.3% respectively; the mass of the environmentally friendly snow-melting corrosion inhibitor of calcium magnesium acetate is 28.69g. After calculation, it can be seen that the product yield is 98.50%; the whiteness of the environmentally friendly snow-melting corrosion inhibitor of calcium magnesium acetate is 98.5; the water content in the alcohol precipitation solution is 0.08%.

[0067] Depend on Figure 1 It can be seen that the environmentally friendly calcium magnesium acetate snow-melting corrosion inhibitor contains diffraction peaks of calcium acetate and magnesium acetate. Therefore, the product obtained by this preparation method is calcium magnesium acetate. Comparative Example 1

[0068] The difference between Comparative Example 1 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, and the other steps remain unchanged.

[0069] During the experiment, it was found that when the dry-basis salt mud to water ratio in the slurry was less than 1g:2mL, after the addition of acetic acid, the reaction lasted approximately 10 minutes before the entire reaction system transformed into a viscous solid-phase aggregate, making the acidification reaction impossible. This viscous solid-phase aggregate formation occurs because the vigorous reaction between acetic acid and the calcium carbonate in the salt mud generates a large amount of heat and carbon dioxide bubbles. This large amount of heat removes some water, and the calcium acetate and other substances produced during the reaction absorb water, resulting in a high solid content in the entire reaction system. Precisely because the low water content further increases the viscosity of the bubbles, they combine with the salt mud to form a viscous solid-phase aggregate, making the acidification reaction impossible with stirring and the salt mud utilization rate zero. Therefore, controlling the amount of water used is a key factor in determining whether the acidification reaction can proceed, and it is important to control the water dosage appropriately. Comparative Example 2

[0070] 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 4875 mL of pure water, and the other steps remain unchanged.

[0071] The yield of the environmentally friendly calcium magnesium acetate snow-melting corrosion inhibitor in step (4) was tested, and the test results are shown in Table 1.

[0072] As shown in Table 1, the mass of the environmentally friendly calcium magnesium acetate snow-melting corrosion inhibitor is 4.79 g. Calculation shows that the product yield is 65.11%. This indicates that excessive use of pure water, under the same conditions, will result in a lower product yield. Comparative Example 3

[0073] The difference between Comparative Example 3 and Example 1 is that no acidifying auxiliary agent allyl polyoxyalkyl epoxy ether is added in step (1), and the other steps remain unchanged.

[0074] During the experiment, it was found that without the addition of an acidifying agent, the acidification reaction was violent, producing a large amount of carbon dioxide gas bubbles that drove the salt mud and solution to overflow, making the reaction dangerous. Therefore, the acidifying agent is a key factor in ensuring a safe and gentle acidification reaction. Comparative Example 4

[0075] The difference between Comparative Example 4 and Example 1 is that in step (1), no acidifying agent allyl polyoxyalkyl epoxy ether and ionic liquid 1-propylamino-3-butyl imidazole tetrafluoroborate are added, and the other operating steps remain unchanged.

[0076] During the experiment, it was found that without the addition of an acidifying agent and ionic liquid, the reactants turned into sticky solid agglomerates. This is because the violent reaction between acetic acid and calcium carbonate in the salt mud produces a large amount of heat and carbon dioxide bubbles. The large amount of heat will carry away some water. The calcium acetate and magnesium acetate produced in the reaction will absorb water, resulting in a high solid content in the entire reaction system. Because the viscosity of the bubbles is further increased in the case of low water content, the bubbles and salt mud combine to form sticky solid agglomerates, making the acidification reaction impossible. Therefore, ionic liquids and acidifying agents are necessary prerequisites for the acidification reaction. Comparative Example 5

[0077] The difference between Comparative Example 5 and Example 1 is that in step (1), 162.5 g of ionic liquid 1-propylamino-3-butylimidazolium tetrafluoroborate is replaced with 162.5 g of pure water and glacial acetic acid is added dropwise in step (2), and the other operating steps remain unchanged.

[0078] The residue in step (2) was dried and weighed. The weighing results are shown in Table 1.

[0079] In step (2), the second mixed solution is subjected to ICP Ca 2+ Mg 2+ Concentration test: the test method is the same as in Example 1, and the test results are shown in Table 1.

[0080] In step (4), the fourth mixed solution is subjected to ICP Ca 2+ Mg 2+ Concentration test: the test method is the same as in Example 1, and the test results are shown in Table 1.

[0081] The yield of the environmentally friendly calcium magnesium acetate snow-melting corrosion inhibitor in step (4) was tested using the same test method as in Example 1. The test results are shown in Table 1.

[0082] As shown in Table 1, the mass of the residue is 66.82 g. The calculation shows that the utilization rate of salt mud is 86.64% and the extraction rate of effective components in salt mud is 96.90%. 2+ Mg 2+ The concentrations are 1.50 moL / L and 0.40 moL / L respectively. It can be calculated that the Ca 2+ Mg 2+ The extraction rates were 99.9% and 90.0% respectively; the Ca 2+ Mg 2+ The concentrations are 40.50mmoL / L and 10.80mmoL / L respectively. It can be calculated that Ca 2+ Mg 2+The precipitation rates were 89.2% and 89.2% respectively; the mass of the environmentally friendly snow-melting corrosion inhibitor of calcium magnesium acetate was 26.25g, and the product yield was 89.2%. It can be seen from this that ionic liquids can affect the addition rate of glacial acetic acid. This is because during the acidification reaction, ionic liquids have amino functional groups or azole functional groups (i.e., nitrogen sites) that can absorb carbon dioxide and reduce the possibility of large bubbles. Ionic liquids also affect the Ca 2+ Mg 2+ The precipitation rate is due to the presence of ionic liquid in the alcohol precipitation process, which reduces the Ca 2+ Mg 2+ The solubility of the alcohol is improved, which improves the alcohol precipitation efficiency. Comparative Example 6

[0083] The difference between Comparative Example 6 and Example 1 is that the amount of acetic acid added in step (1) is different, that is, the amount of acetic acid added is changed from 8.5 mol to 5.0 mol, and the other operating steps remain unchanged.

[0084] The residue in step (2) was dried and weighed. The weighing results are shown in Table 1. In step (2), the second mixed solution is subjected to ICP Ca 2+ Mg 2+ Concentration test, test results are shown in Table 1.

[0085] In step (4), the fourth mixed solution is subjected to ICP Ca 2+ Mg 2+ Concentration test: the test method is the same as in Example 1, and the test results are shown in Table 1.

[0086] The yield of the environmentally friendly calcium magnesium acetate snow-melting corrosion inhibitor in step (4) was tested using the same test method as in Example 1. The test results are shown in Table 1.

[0087] As shown in Table 1, the mass of the residue after drying is 256.11 g. Calculation shows that the utilization rate of salt mud is 48.78%, and the extraction rate of effective components in salt mud reaches 54.5%. 2+ Mg 2+ The concentrations are 0.872moL / L and 0.228moL / L respectively. It can be calculated that the Ca 2+ Mg 2+ The extraction rates were 51.50% and 45.90% respectively; the Ca 2+ Mg 2+ The concentrations are 42.51mmoL / L and 11.11mmoL / L respectively. It can be calculated that Ca 2+ Mg 2+The precipitation rates were 80.5% and 80.5%, respectively. The mass of the environmentally friendly calcium magnesium acetate snow-melting corrosion inhibitor was 13.72g, and the product yield was calculated to be 80.50%. This shows that when the amount of acetic acid added is small, it not only affects the acidification efficiency but also the alcohol precipitation efficiency. Comparative Example 7

[0088] The difference between Comparative Example 7 and Example 1 is that the alcohol precipitation reaction conditions in step (4) are different, and the alcohol precipitation temperature is changed from 45°C to 80°C, while the other operating steps remain unchanged.

[0089] During the alcohol precipitation reaction, it was found that when the alcohol precipitation temperature was higher than 60°C, the reaction solution in the alcohol precipitation process quickly turned into a gel state. This is because the alcohol precipitation reaction temperature is too high, and the calcium magnesium acetate particles in the solution quickly nucleate, grow and precipitate. The particles also stick to each other, causing the solution to become a gel state, making it difficult to remove the material, and thus preventing industrialization. Therefore, the temperature of the alcohol precipitation reaction must be appropriately controlled. Comparative Example 8

[0090] The difference between Comparative Example 8 and Example 1 is that the alcohol precipitation reaction conditions in step (4) are different, the stirring speed is changed from 450 r / min to 50 r / min, and the other operating steps remain unchanged.

[0091] During the alcohol precipitation reaction, it was found that when the stirring speed was lower than 300 r / min, the reaction solution quickly turned into a gel state. This is because the stirring speed was too low, causing the particles to rapidly nucleate, grow, and adhere to each other. The solution would then become gel-like, making it difficult to remove the material, thus preventing industrialization. Therefore, the stirring speed of the alcohol precipitation reaction should be appropriately controlled. Comparative Example 9

[0092] The difference between Comparative Example 9 and Example 1 is that there are no steps (3) to (5). The specific operation steps are as follows: 100 mL of the second mixed solution was placed in a beaker and sealed with tin foil, and the water was evaporated in a blast drying oven at 90-110° C. After evaporation for 12 hours, an environmentally friendly snow-melting corrosion inhibitor of calcium magnesium acetate was obtained.

[0093] The yield and whiteness of the calcium magnesium acetate environmentally friendly snow-melting corrosion inhibitor were tested using the same test method as in Example 1. The test results are shown in Table 1.

[0094] As shown in Table 1, the mass of the product is 29.42 g. The yield is 100% and the whiteness is 90.5. Compared with the whiteness of Example 1, the whiteness of Example 1 is 1.09 times that of Comparative Example 9. This is because the solution contains Fe 3+ The whiteness decreases due to impurity ions or air oxidation, but the alcohol precipitation method does not need to worry about Fe 3+The influence of impurity ions is reduced, the operation steps are reduced, and the process operation cost is reduced. In addition, the alcohol precipitation method of Example 1 takes 48 minutes, while the evaporation concentration method of Comparative Example 9 takes 720 minutes. Example 1 is 15 times faster than Comparative Example 9. The alcohol precipitation method can also significantly save time and reduce energy consumption. Comparative Example 10

[0095] The difference between Comparative Example 10 and Example 1 is that the salt mud is not crushed in step (1), and the other steps remain unchanged.

[0096] The residue in step (2) was dried and weighed. The weighing results are shown in Table 1.

[0097] As shown in Table 1, the residue was 363.51 g. Calculation showed that the salt mud utilization rate was 27.30%, far lower than that of Example 1. This is because large pieces of salt mud are difficult to acidify. Therefore, the crushing of salt mud is a key factor in the acidification reaction. Comparative Example 11

[0098] The difference between Comparative Example 11 and Example 1 is that the particle size of the salt mud crushed in step (1) is different, and the particle size of the solid phase in the salt mud crushed is 1200 mesh, and the other steps remain unchanged.

[0099] The residue in step (2) was dried and weighed. The weighing results are shown in Table 1.

[0100] During the experiment, we found that some salt mud floated on the surface. This was because long-term crushing caused the material to heat up rapidly, moisture to evaporate, the mass of individual salt mud particles to decrease, and they were easy to float, resulting in untimely reaction between salt mud and acetic acid, and thus a decrease in salt mud utilization rate.

[0101] As shown in Table 1, the residue is 113.522 g. Calculation shows that the salt mud utilization rate is 77.30%, which is far lower than the effect of Example 1. Therefore, regulating the particle size of the salt mud is also a key factor in the acidification reaction.

[0102]

[0103] As can be seen from the above, by comparing Comparative Examples 1-2 and Example 1, it is found that when the ratio of the mass of salt mud to water on a dry basis is less than 1g:2mL or greater than 1g:4mL, the acidification reaction effect and the alcohol precipitation reaction effect will be affected; when the ratio of the mass of salt mud to water on a dry basis is less than 1g:2mL, the solution forms a viscous solid phase agglomerate; when the ratio of the mass of salt mud to water on a dry basis is greater than 1g:4mL, the concentration of the solution containing calcium magnesium acetate decreases, resulting in a decrease in the precipitation effect of the alcohol precipitation reaction under the same conditions, affecting the precipitation efficiency. Therefore, the amount of pure water should be appropriately controlled. By comparing Comparative Example 3 with Example 1, it can be seen that the acidification aid can suppress the generation of large bubbles of carbon dioxide, disperse large bubbles into small bubbles, and prevent the solution from overflowing, which is a key factor in the safe and gentle conduct of the acidification reaction. By Comparative Example 4 and Example 1, it can be seen that the ionic liquid and the acidification aid have a synergistic effect, and can also prevent the solution from becoming a viscous solid phase agglomerate, which is a key factor in maintaining the gentle conduct of the acidification reaction. From the comparison between Comparative Example 5 and Example 1, it can be seen that the ionic liquid can absorb carbon dioxide, reduce the possibility of large bubbles, and have a synergistic effect with the acidification aid, prompting the one-time addition of acetic acid and accelerating the process of the acidification reaction; at the same time, the ionic liquid also affects the Ca 2+ Mg 2+ The precipitation rate, therefore, ionic liquid is an indispensable condition for the entire reaction process. By comparing Comparative Example 6 with Example 1, it can be seen that when the amount of acetic acid added is small, it not only affects the acidification efficiency, but also affects the alcohol analysis efficiency. Therefore, it is necessary to appropriately control the amount of acetic acid added. By comparing Comparative Examples 7-8 with Example 1, it can be seen that the alcohol analysis temperature and stirring speed in the alcohol analysis reaction conditions will affect the alcohol analysis effect. Therefore, it is necessary to appropriately control the alcohol analysis reaction conditions. By comparing Comparative Example 9 with Example 1, it can be seen that the traditional evaporation and concentration method for preparing calcium magnesium acetate environmentally friendly snow melting corrosion inhibitor is not only time-consuming and low in whiteness, but also high in energy consumption. By comparing Comparative Examples 10-11 with Example 1, it can be seen that the particle size of the pulverized salt mud of 200-500 mesh is another key factor in the acidification reaction.

Claims

1. A method for preparing an environmentally friendly snow-melting corrosion inhibitor of calcium magnesium acetate by comprehensive utilization of chlor-alkali salt mud solid waste, characterized in that: The following steps are involved: (1) The solid phase in the salt mud is crushed into 200-500 mesh particles, and then mixed with water to form a slurry, and the ratio of the mass of the salt mud to water in the slurry on a dry basis is controlled to be 1g:2-4mL, and then an acidifying agent and an ionic liquid are added to the slurry to obtain a first mixed solution; (2) Adding acetic acid to the first mixed solution at once under stirring, reacting at 25-85°C for 1-4 hours, and separating to obtain a residue and a second mixed solution; (3) mixing a water-soluble alcohol organic solvent with a ketone organic solvent or an ester organic solvent to prepare an alcohol precipitation solution, adding the alcohol precipitation solution to the second mixed solution to carry out an alcohol precipitation reaction, and obtaining a third mixed solution; (4) The third mixed solution is separated to obtain a crude calcium magnesium acetate environmentally friendly snow-melting corrosion inhibitor and a fourth mixed solution; the crude calcium magnesium acetate environmentally friendly snow-melting corrosion inhibitor is dried to obtain a calcium magnesium acetate environmentally friendly snow-melting corrosion inhibitor; the fourth mixed solution is subjected to reduced pressure distillation to obtain a gaseous mixture of a water-soluble alcohol organic solvent, a ketone organic solvent or an ester organic solvent, and water at the top, and the gaseous mixture of the water-soluble alcohol organic solvent, the ketone organic solvent or the ester organic solvent, and water is condensed to obtain a fifth mixed solution; a reaction residue is obtained at the bottom, and the reaction residue is recycled; (5) 3A molecular sieve is added to the fifth mixed solution for adsorption, and then separated to obtain an alcohol precipitation solution and the adsorbed 3A molecular sieve. The alcohol precipitation solution is returned to step (4) for recycling, and the adsorbed 3A molecular sieve is regenerated and reused.

2. The method for preparing calcium magnesium acetate environmentally friendly snow-melting corrosion inhibitor by comprehensive utilization of chlor-alkali salt mud solid waste according to claim 1, characterized in that: In the step (1), the acidifying aid is one of allyl polyoxyalkyl epoxy ether, allyl alcohol polyoxyalkyl ether, or nonylphenol polyoxyethylene ether; and the ionic liquid is one of 1-propylamino-3-butylimidazole tetrafluoroborate, 1-(2-aminoethyl)-2-methylpyrazole bromide, or tetra-n-heptyl ammonium bromide.

3. The method for preparing an environmentally friendly snow-melting corrosion inhibitor of calcium magnesium acetate by comprehensive utilization of chlor-alkali salt mud solid waste according to claim 1, characterized in that: In the step (1), the ratio of the amount of the acidifying agent added to the total amount of water in the first mixed solution is 0.003-0.008 g:1 mL; the ratio of the amount of the ionic liquid added to the total amount of water in the first mixed solution is 0.1-0.15 g:1 mL.

4. The method for preparing an environmentally friendly snow-melting corrosion inhibitor of calcium magnesium acetate by comprehensive utilization of chlor-alkali salt mud solid waste according to claim 1, characterized in that: In the step (2), the stirring speed is 100-300 r / min; the mass ratio of acetic acid to the salt mud in the first mixed solution on a dry basis is 0.016-0.019 mol:1 g.

5. The method for preparing calcium magnesium acetate environmentally friendly snow-melting corrosion inhibitor by comprehensive utilization of chlor-alkali salt mud solid waste according to claim 1, characterized in that: In the step (3), the alcohol organic solvent is one of methanol or ethanol; the ketone organic solvent is one of acetone or ethylketone; and the ester organic solvent is one of ethyl acetate or methyl acetate.

6. The method for preparing calcium magnesium acetate environmentally friendly snow-melting corrosion inhibitor by comprehensive utilization of chlor-alkali salt mud solid waste according to claim 1, characterized in that: In the step (3), the volume ratio of the alcohol organic solvent to the ketone organic solvent or the ester organic solvent in the alcohol precipitation solution is 1:2-4; the volume ratio of the added amount of the alcohol precipitation solution to the second mixed solution is 1-5:

1.

7. The method for preparing calcium magnesium acetate environmentally friendly snow-melting corrosion inhibitor by comprehensive utilization of chlor-alkali salt mud solid waste according to claim 1, characterized in that: In step (3), the alcohol precipitation reaction conditions are: alcohol precipitation temperature 30-60°C, alcohol precipitation time 0.5-1h, and stirring speed 300-600r / min.

8. The method for preparing calcium magnesium acetate environmentally friendly snow-melting corrosion inhibitor by comprehensive utilization of chlor-alkali salt mud solid waste according to claim 1, characterized in that: In the step (4), the drying conditions are: vacuum drying at 40-60°C and vacuum drying time of 1-2 hours; the reaction residue is recycled and reused by returning the reaction residue to step (1) for use as water.

9. The method for preparing calcium magnesium acetate environmentally friendly snow-melting corrosion inhibitor by comprehensive utilization of chlor-alkali salt mud solid waste according to claim 1, characterized in that: In the step (5), the adsorption conditions are as follows: the amount of 3A molecular sieve added is 2-5% of the mass of the fifth mixed solution, the adsorption time is 0.5-1 h, and the stirring speed is 200-300 r / min.

10. The method for preparing calcium magnesium acetate environmentally friendly snow-melting corrosion inhibitor by comprehensive utilization of chlor-alkali salt mud solid waste according to claim 1, characterized in that: In the step (5), the adsorbed 3A molecular sieve is regenerated and recycled under the following conditions: vacuum drying temperature of 100-150°C and vacuum drying time of 1-3h.

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