Method for preparing calcium-magnesium acetate environment-friendly snow-melting corrosion inhibitor from chlor-alkali salt mud solid waste

Abstract

The application provides a method for preparing calcium-magnesium acetate environment-friendly snow-melting corrosion inhibitor from chlor-alkali salt mud solid waste, and belongs to the technical field of comprehensive utilization of solid waste and organic material synthesis. Firstly, the chlor-alkali salt mud is prepared into slurry with water, then under the action of acidification aid and ionic liquid, the acetate is added at one time, and then the calcium-magnesium acetate environment-friendly snow-melting corrosion inhibitor is precipitated in the alcohol precipitation solution. The method can achieve 84.13-87.26% of the utilization rate of the salt mud, 95-99.99% and 85-92% of the extraction rates of Ca 2+ and Mg 2+ in the salt mud respectively, basically realizing the full recovery of high-value components in the salt mud. The precipitation rates of Ca 2+ and Mg 2+ in the solution are 96.4-99.9% and 96.6-99.9% respectively, basically realizing the full precipitation of Ca 2+ and Mg 2+ , the product yield reaches 96.5-99.9%, the whiteness of the product reaches more than 98.0, no waste liquid is generated in the whole process, and the recycling of the salt mud solid waste is realized.

Description

Technical Field

[0001] This invention belongs to the field of comprehensive utilization of solid waste resources and synthesis of organic materials, specifically relating to a method for preparing an environmentally friendly calcium magnesium acetate snow melting corrosion inhibitor 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. The main components of its dry-basis salt mud 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%), with the remainder being insoluble matter (approximately 10.5%, mainly CaSO4 and SiO2). Currently, most salt mud from the chlor-alkali industry both domestically and internationally 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, especially the recovery and utilization of calcium and magnesium elements, has become a hot topic of research for researchers both domestically and internationally.

[0004] Calcium magnesium acetate (CMA), a mixture of calcium acetate and magnesium acetate, is a novel environmentally friendly de-icing agent. Compared to existing chloride-based de-icing agents, which account for over 90% of applications, CMA offers advantages such as low corrosivity, biodegradability, and minimal harm to plants. However, the current process for producing CMA from oxides and acetic acid through evaporation, concentration, and crystallization suffers from high raw material costs and energy consumption, limiting its widespread use and application, typically limited to special applications such as airports and highways. Furthermore, when using high-calcium- and magnesium-containing solid wastes such as salt mud, phosphate tailings, or dolomite as inexpensive raw materials, the resulting solution often exhibits a reddish-brown color due to iron content. Traditionally, this requires adding adsorbents to remove iron impurities to meet the national standard for de-icing agent whiteness (GB / T 23851-2017), but this adds adsorption and regeneration steps, increasing operating costs. Therefore, developing an inexpensive calcium magnesium acetate production process is crucial for the widespread adoption of environmentally friendly calcium magnesium acetate de-icing and corrosion inhibitors. Currently, there is no method for preparing environmentally friendly calcium magnesium acetate snow-melting corrosion inhibitors without evaporation and crystallization.

[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 an acidifying agent of acetic acid. The mixture is then evaporated and concentrated to obtain a high-concentration calcium-magnesium solution. A corrosion inhibitor is added, and the mixture is spray-dried and granulated to obtain the de-icing agent. During the acidification process, researchers sometimes reduce the risk of overflow by adding acetic acid or increasing the volume of the reaction vessel to mitigate the possibility of overflow caused by the vigorous reaction of acetic acid and salt mud producing large amounts of carbon dioxide gas. However, this increases the total acidification time and reduces the utilization rate of the reaction vessel volume. Alternatively, researchers control the rate of carbon dioxide gas generation by reducing the instantaneous concentration of the acetic acid, i.e., by increasing the liquid-to-solid ratio of the water-salt mud slurry, thus reducing the risk of overflow. However, adding large amounts of water leads to a decrease in the calcium-magnesium concentration in the reaction system, 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 solution, and low cost is a focus of attention for enterprises and researchers.

[0006] Chinese invention patent document CN119039133A discloses a method for preparing calcium magnesium acetate from phosphorus tailings, its application, and its preparation. The method involves calcining phosphorus tailings at high temperature to obtain oxides, then adding an aqueous solution containing acetic acid. The liquid-to-solid ratio of the solution to the calcined phosphorus tailings is controlled at 6-14:1, and the amount of acetic acid in the aqueous solution is 86-106% of the theoretical amount. The reaction is carried out at room temperature for 15-40 minutes to obtain a calcium magnesium acetate solution. The calcium magnesium acetate solution is then evaporated, concentrated, and crystallized to obtain calcium magnesium acetate. As described in paragraph 0095 of the patent specification, the maximum extraction rates for calcium and magnesium reach 94.24% and 95.53%, respectively, meaning the concentrations of calcium and magnesium ions in the calcium-magnesium acetate solution are 0.069-0.16 mol / L and 0.042-0.097 mol / L, respectively. The resulting calcium-magnesium acetate solution has a relatively low concentration because the patent increases the amount of solvent water to improve the extraction rate of calcium and magnesium from phosphate tailings, sacrificing the solution concentration. Therefore, the energy consumption during the evaporation, concentration, and crystallization of the calcium-magnesium acetate solution is enormous. Furthermore, the phosphate tailings precursor requires high-temperature calcination. This is because the patent uses calcination to convert carbonates into oxides to reduce the amount of acetic acid used and the reaction time. While the reaction rate of acetic acid with oxides is faster than that with carbonates, this increases energy consumption and is uneconomical.

[0007] Chinese invention patent document CN106497517A discloses a method for preparing an organic environmentally friendly de-icing agent using salt mud via a two-alkali process. This method involves mixing salt mud with water to form a slurry, then adding organic acid dropwise. The mixture is then filtered, concentrated by vacuum evaporation, spray-dried, and granulated by roller milling to obtain a calcium magnesium acetate environmentally friendly de-icing agent. Because the slurry prepared from the salt mud contains a large amount of calcium carbonate, and the reaction system requires the addition of excess organic acid, the reaction between the organic acid and calcium carbonate produces a large amount of carbon dioxide bubbles, posing a risk of overflow. Therefore, to reduce the overflow risk, researchers added the organic acid slowly, but this significantly prolonged the reaction time and reduced production efficiency. Due to the presence of impurities such as iron in the salt mud, the solution appears yellow or reddish-brown. Without an adsorbent-based impurity removal process, the whiteness of the produced calcium magnesium acetate environmentally friendly de-icing agent decreases, failing to meet the requirements of the national standard for de-icing agent whiteness (GB / T 23851-2017). Furthermore, this patent does not address the utilization rate of the salt mud throughout the process; it only describes the performance of the calcium magnesium acetate environmentally friendly de-icing agent. Summary of the Invention

[0008] The technical problem this invention aims to solve is to provide a method for preparing environmentally friendly calcium magnesium acetate snow-melting corrosion inhibitors through the comprehensive utilization of chlor-alkali salt mud solid waste. This method addresses the issues of excessively long addition time of acidifying reagents or low volume utilization of the acidification reactor during the salt mud acidification process. Simultaneously, it also solves the problems of long preparation time, high energy consumption, and low whiteness in traditional calcium magnesium acetate environmentally friendly snow-melting corrosion inhibitor preparation processes. Furthermore, it enables value-added utilization of salt mud, reduced emissions, and the transformation of waste into treasure, effectively promoting the healthy development of the chlor-alkali industry and demonstrating broad prospects for industrial application.

[0009] To address the above problems, the present invention provides a method for preparing an environmentally friendly calcium magnesium acetate snow-melting corrosion inhibitor through comprehensive utilization of chlor-alkali salt mud solid waste, comprising the following steps:

[0010] (1) The solid phase in the salt mud is crushed into 200-500 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) Acetic acid is added to the first mixed solution in one go under stirring, and the reaction is carried out at 25-85℃ for 1-4 hours. After separation, the residue and the second mixed solution are obtained.

[0012] (3) Prepare an alcohol precipitation solution by mixing water-soluble alcohol organic solvents with ketone organic solvents or ester organic solvents, 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 calcium magnesium acetate environmentally friendly snow melting corrosion inhibitor and the fourth mixed solution; the crude calcium magnesium acetate environmentally friendly snow melting corrosion inhibitor is dried to obtain calcium magnesium acetate environmentally friendly snow melting corrosion inhibitor; the fourth mixed solution is distilled under reduced pressure to obtain a gaseous mixture of water-soluble alcohol organic solvent, ketone organic solvent or ester organic solvent and water at the top; the mixture of water-soluble alcohol organic solvent, ketone organic solvent or ester organic solvent and water is condensed to obtain the fifth mixed solution; the bottom is the reaction residue, which is then 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 0.003-0.008g:1mL; the ratio of the amount of ionic liquid added to the total amount of water in the first mixed solution is 0.1-0.15g:1mL.

[0017] Further, in step (2), the stirring speed is 100-300 r / min; the mass ratio of acetic acid to salt mud in the first mixed solution on a dry basis is 0.016-0.019 mol: 1 g.

[0018] Further, in step (3), the 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.

[0019] Furthermore, in step (3), the volume ratio of alcohol organic solvent to ketone organic solvent or ester organic solvent in the alcohol precipitation solution is 1:2-4; the volume ratio of the amount of alcohol precipitation solution added to the volume ratio of the second mixed solution is 1-5:1.

[0020] Furthermore, in step (3), the alcohol precipitation reaction conditions are: alcohol precipitation temperature 30-60℃, alcohol precipitation time 0.5-1h, and stirring speed 300-600r / min.

[0021] 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.

[0022] Further, in step (5), the adsorption conditions are: the amount of 3A molecular sieve added is 2-5% of the mass of the fifth mixed solution, the adsorption time is 0.5-1h, and the stirring speed is 200-300r / min.

[0023] 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.

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

[0025] (1) This invention helps to promote the acidification reaction process by crushing the solid phase in the salt mud into fine particles of 200-500 mesh, thereby improving the utilization rate of salt mud and the extraction rate of effective components in the salt mud.

[0026] (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+ Mg 2+ The precipitation rate is high. In addition, the acidification aid disperses large carbon dioxide bubbles into smaller bubbles, which are more easily broken during the stirred reaction. This has a synergistic effect with the ionic liquid's ability to adsorb carbon dioxide bubbles in situ, thus optimizing the acidification reaction. Therefore, there is no need to control the dropping rate of acetic acid, and acetic acid can be added directly in one go, laying the foundation for continuous industrial operation.

[0027] (3) This invention optimizes the amount of water added, reaction temperature, reaction time, and amount of acetic acid added, while ensuring a high concentration of calcium and magnesium-containing solution, to achieve high utilization of salt mud and extraction of effective components from 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 reached 95-99.99% and 85-92% respectively, for Ca in salt mud. 2+ and Mg 2+ High-value components are basically fully recovered, 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.

[0028] (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 solvent to ketone organic solvent or ester organic solvent, 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+ 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 reached 96.5-99.9%, and the whiteness of the product exceeded 98.0%. This method is 15 times faster than direct evaporation and concentration for preparing environmentally friendly calcium magnesium acetate de-icing corrosion inhibitors, and the whiteness of the product from direct concentration crystallization is 1.09 times higher. Furthermore, the use of organic solvents for alcohol precipitation of calcium magnesium acetate reduces the drying requirements and energy consumption. Additionally, the selected water-soluble alcohols, ketones, or esters have low boiling points and are inexpensive, allowing for easy distillation and recovery, thus reducing operating costs.

[0029] (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 reduces the process operating cost. At the same time, the 3A molecular sieve can be repeatedly regenerated through drying, realizing a circular economy.

[0030] (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. Attached Figure Description

[0031] Figure 1 The X-ray diffraction (XRD) structure diagram of the environmentally friendly calcium magnesium acetate snow melting corrosion inhibitor obtained in step (4) of Examples 1-5;

[0032] Figure 2 The image shows the scanning electron microscope (SEM) morphology of the environmentally friendly calcium magnesium acetate snow melting corrosion inhibitor obtained in step (4) of Example 1. Detailed Implementation

[0033] 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.

[0034] 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

[0035] (1) The solid phase in the salt mud was crushed into 500 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 1125mL of pure water was added and mixed evenly to prepare a slurry. 6.25g of allyl polyoxyalkyl epoxy ether and 162.5g of 1-propylamino-3-butylimidazolium tetrafluoroborate were added to the slurry and mixed evenly to obtain the first mixed solution.

[0036] (2) Add 8.5 mol of 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 filtration to obtain the residue and the second mixed solution;

[0037] (3) Prepare an alcohol precipitation solution by mixing methanol and acetone in a volume ratio of 1:3. Take 100 mL of the second mixed solution and add 400 mL of alcohol precipitation solution to the second mixed solution to carry out the alcohol precipitation reaction. Control the alcohol precipitation temperature at 45℃, the alcohol precipitation time at 0.8 h, and the stirring rate at 450 r / min to obtain the third mixed solution.

[0038] (4) The third mixed solution is filtered and separated to obtain crude calcium magnesium acetate environmentally friendly snow melting corrosion inhibitor and the fourth mixed solution. The crude calcium magnesium acetate environmentally friendly snow melting corrosion inhibitor is vacuum dried at 50°C for 1.5h to obtain calcium magnesium acetate environmentally friendly snow melting corrosion inhibitor. The fourth mixed solution is distilled under reduced pressure in a distillation tower. A mixture of gaseous methanol, acetone and water is obtained at the top. The mixture of gaseous methanol, acetone 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.

[0039] (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 0.8h, 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 120℃ for 2h and then regenerated for recycling.

[0040] The residue in step (2) was dried and weighed. The weighing results are shown in Table 1.

[0041] In step (2), the second mixed solution was subjected to inductively coupled plasma atomic emission spectrometry (ICP) for Ca... 2+ Mg 2+ Concentration test results are shown in Table 1.

[0042] In step (4), the fourth mixed solution is subjected to ICP Ca2+. 2+ Mg 2+ Concentration test results are shown in Table 1.

[0043] The X-ray diffraction (XRD) structure, scanning electron microscopy (SEM) morphology, yield, and whiteness of the calcium magnesium acetate environmentally friendly snow-melting corrosion inhibitor in step (4) were tested. The test results are shown in the figure below. Figure 1 , Figure 2 Table 1.

[0044] The moisture content of the alcohol precipitation solution in step (5) was tested, and the test results are shown in Table 1.

[0045] 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 utilization rate of salt mud is %; m0 is the dry weight of salt mud, g; m1 is the dry weight of the residue, g. Where m0 is 500 g.

[0046] 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.

[0047] ICP's Ca 2+ and Mg 2+ Concentration testing method: Standard curves for calcium acetate or magnesium acetate solutions of different concentrations were prepared by mixing calcium acetate and magnesium acetate with deionized water, respectively. The average error was ≥0.999. The Ca content of the test sample was determined based on the standard curves of the calcium acetate and magnesium acetate solutions. 2+ Concentration and Mg 2+ concentration.

[0048] Ca in salt mud 2+ Mg 2+ The extraction rate test is performed as follows: The Ca in the second mixed solution in step (2) 2+ Mg 2+ Concentration and volume, thus obtaining the amount of Ca and Mg remaining in the fourth mixed solution (mol); Take 625g of salt mud, given the mass fractions of CaCO3 and Mg(OH)2 in the dry salt mud, thus obtaining the amount of Ca and Mg in the salt mud (mol). 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 For the second mixed solution Ca 2+ Mg 2+ 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 The content of CaCO3 and Mg(OH)2 in dry-based salt mud, %; M CaCO3 / Mg（OH）2 represents the relative molar mass of CaCO3 or Mg(OH)2, in g / mol. Where X... CaCO3 It is 58.5%, X Mg(OH)2 The content is 10.0%, and m0 is 500g.

[0049] Ca in the second mixed solution 2+ Mg 2+ The precipitation rate test is performed as follows: the Ca in the fourth mixed solution in step (4) 2 + Mg 2+ Concentration and volume, and thus the amount of Ca and Mg remaining in the fourth mixed solution (mol); Ca in the second mixed solution in step (3) 2+ Mg 2+ The concentration and volume are used to obtain the amount of substance (mol) of Ca and Mg in the second mixed solution, that is, the amount of substance (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 For Ca2+ Mg 2+ Extraction rate, %; C Ca或Mg，第二混合溶液 For the second mixed solution Ca 2+ Mg 2+ Concentration, mol / L; V 第二混合溶液 The volume of the second mixed solution is L; C Ca或Mg，第四混合溶液 For the fourth mixed solution, Ca 2+ Mg 2+ Concentration, mol / L; V 第四混合溶液 Let L be the volume of the fourth mixed solution.

[0050] The yield test operation of the environmentally friendly calcium magnesium acetate snow melting corrosion inhibitor is as follows: the environmentally friendly calcium magnesium acetate snow melting corrosion inhibitor in step (5) is dried and weighed to obtain m2; the Ca in the second mixture in step (3) 2+ Mg 2+ The amount of substance (mol) of the corresponding environmentally friendly calcium magnesium acetate snow-melting corrosion inhibitor was calculated based on the concentration and volume, and then the theoretical mass (m³) of the environmentally friendly calcium magnesium acetate snow-melting corrosion inhibitor was obtained. max The formula is: Y 融雪缓蚀剂 =m2 / m max ×100%, Y 融雪缓蚀剂 ... max For the Ca in the second mixture 2+ Mg 2+ The total mass of the theoretically converted calcium magnesium acetate environmentally friendly snow melting corrosion inhibitor, in g.

[0051] 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.

[0052] Whiteness test method for environmentally friendly calcium magnesium acetate snow melting corrosion inhibitor: First, preheat the WSB-3C fluorescence whiteness meter for more than 15 seconds, then zero it, then place the calibration reference white plate on the sample holder for calibration, and perform multiple calibrations with an error range of ±0.1. Finally, place the sample to be tested on the sample holder and take the reading.

[0053] Table 1 shows that the mass of the dried residue was 65.925 g. Calculations indicate that the utilization rate of the salt mud was 86.82%, and the extraction rate of the effective components from the salt mud reached 97.0%. The Ca content in the second mixed solution... 2+ Mg 2+ With concentrations of 1.50 mol / L and 0.40 mol / L, respectively, calculations show that the effect on Ca in the salt mud is... 2+Mg 2+ The extraction rates were 99.9% and 90.0%, respectively; the Ca in the fourth mixed solution 2+ Mg 2+ The concentrations were 1.88 mmol / L and 0.50 mmol / L, respectively. Calculations show that Ca... 2+ Mg 2+ The precipitation rates were 99.5% and 99.5% respectively; the mass of the environmentally friendly calcium magnesium acetate snow-melting corrosion inhibitor was 29.28g, and the product yield was calculated to be 99.5%; the whiteness of the environmentally friendly calcium magnesium acetate snow-melting corrosion inhibitor was 98.5; and the water content in the alcohol precipitation solution was 0.3%.

[0054] Depend on Figure 1 It is known that the environmentally friendly snow melting corrosion inhibitor containing calcium acetate and magnesium acetate contains diffraction peaks. Therefore, the product obtained by this preparation method is calcium acetate.

[0055] Depend on Figure 2 It can be seen that the morphology of calcium magnesium acetate environmentally friendly snow melting corrosion inhibitor is tubular. Example 2

[0056] (1) The solid phase in the salt mud was crushed into 400 mesh particles by a high-moisture vertical crusher. After crushing, the water content of the salt mud was measured to be 20% by a solid content detector. 625g of crushed salt mud was weighed and then 875mL of pure water was added and mixed evenly to prepare a slurry. 8.0g of allyl alcohol polyoxyalkyl ether and 150g of 1-(2-aminoethyl)-2-methylpyrazole bromide were added to the slurry and mixed evenly to obtain the first mixed solution.

[0057] (2) Add 8.0 mol of glacial acetic acid to the first mixed solution at a stirring speed of 100 r / min, react at 25 °C for 4 h, and then separate by filtration to obtain the residue and the second mixed solution;

[0058] (3) Prepare an alcohol precipitation solution by mixing methanol and ethyl ketone in a volume ratio of 1:2. Take 100 mL of the second mixed solution and add 100 mL of the alcohol precipitation solution to the second mixed solution to carry out the alcohol precipitation reaction. Control the alcohol precipitation temperature at 60℃, the alcohol precipitation time at 0.5 h, and the stirring rate at 600 r / min to obtain the third mixed solution.

[0059] (4) The third mixed solution is filtered and separated to obtain crude calcium magnesium acetate environmentally friendly snow melting corrosion inhibitor and the fourth mixed solution. The crude calcium magnesium acetate environmentally friendly snow melting corrosion inhibitor is vacuum dried at 40℃ for 2.0h to obtain calcium magnesium acetate environmentally friendly snow melting corrosion inhibitor. The fourth mixed solution is distilled under reduced pressure in a distillation tower. A mixture of gaseous methanol, ethyl ketone and water is obtained at the top. The mixture of gaseous methanol, ethyl ketone 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.

[0060] (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 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. 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.

[0061] The residue in step (2) was dried and weighed. The weighing results are shown in Table 1.

[0062] In step (2), the second mixed solution undergoes ICP Ca2+ ionization. 2+ Mg 2+ Concentration testing was conducted using the same method as in Example 1, and the results are shown in Table 1.

[0063] In step (4), the fourth mixed solution is subjected to ICP Ca2+. 2+ Mg 2+ Concentration testing was conducted using the same method as in Example 1, and the results are shown in Table 1.

[0064] The XRD structure, yield, and whiteness of the calcium magnesium acetate environmentally friendly snow-melting corrosion inhibitor in step (4) were tested using the same methods as in Example 1. The test results are shown in [Figure 1]. Figure 1 Table 1.

[0065] Table 1 shows that the mass of the dried residue was 79.350 g. Calculations indicate that the utilization rate of the salt mud was 84.13%, and the extraction rate of the effective components from the salt mud reached 94.0%. The Ca content in the second mixed solution... 2+ Mg 2+ The concentrations were 1.68 mol / L and 0.44 mol / L, respectively. Calculations showed that the effect on Ca in the salt mud... 2+ Mg 2+ The extraction rates were 95.0% and 85.0%, respectively; the Ca in the fourth mixed solution 2+ Mg 2+ The concentrations were 30.24 mmol / L and 7.48 mmol / L, respectively. Calculations show that Ca... 2+Mg 2+ The precipitation rates were 96.4% and 96.6%, respectively; the mass of the environmentally friendly calcium magnesium acetate snow-melting corrosion inhibitor was 31.69 g, and the product yield was calculated to be 96.5%; the whiteness of the environmentally friendly calcium magnesium acetate snow-melting corrosion inhibitor was 98.0; and the water content in the alcohol precipitation solution was 0.5%.

[0066] Depend on Figure 1 It is known that the environmentally friendly snow melting corrosion inhibitor containing calcium acetate and magnesium acetate contains diffraction peaks. Therefore, the product obtained by this preparation method is calcium acetate. Example 3

[0067] (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. 6.0g of nonylphenol polyoxyethylene ether and 200g of tetrahedral ammonium bromide were added to the slurry and mixed evenly to obtain the first mixed solution.

[0068] (2) Add 9.5 mol of 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 the residue and the second mixed solution;

[0069] (3) Prepare an alcohol precipitation solution by mixing methanol and ethyl acetate in a volume ratio of 1:4. Take 100 mL of the second mixed solution and add 500 mL of the alcohol precipitation solution to the second mixed solution to carry out the alcohol precipitation reaction. Control the alcohol precipitation temperature at 30℃, the alcohol precipitation time at 1.0 h, and the stirring rate at 300 r / min to obtain the third mixed solution.

[0070] (4) The third mixed solution is centrifuged to obtain crude calcium magnesium acetate environmentally friendly snow melting corrosion inhibitor and the fourth mixed solution. The crude calcium magnesium acetate environmentally friendly snow melting corrosion inhibitor is vacuum dried at 60℃ for 1.0h to obtain calcium magnesium acetate environmentally friendly snow melting corrosion inhibitor. The fourth mixed solution is distilled under reduced pressure in a distillation tower. A mixture of gaseous methanol, ethyl acetate and water is obtained at the top. The mixture of gaseous methanol, ethyl 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.

[0071] (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 5.0% of the mass of the fifth mixed solution, the adsorption time is 0.5h, 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 150℃ for 1h and then regenerated for recycling.

[0072] The residue in step (2) was dried and weighed. The weighing results are shown in Table 1.

[0073] In step (2), the second mixed solution undergoes ICP Ca2+ ionization. 2+ Mg 2+ Concentration testing was conducted using the same method as in Example 1, and the results are shown in Table 1.

[0074] In step (4), the fourth mixed solution is subjected to ICP Ca2+. 2+ Mg 2+ Concentration testing was conducted using the same method as in Example 1, and the results are shown in Table 1.

[0075] The XRD structure, yield, and whiteness of the calcium magnesium acetate environmentally friendly snow-melting corrosion inhibitor in step (4) were tested using the same methods as in Example 1. The test results are shown in [Figure 1]. Figure 1 Table 1.

[0076] Table 1 shows that the mass of the residue after drying is 63.688 g. Calculations indicate that the utilization rate of the salt mud is 87.26%, and the extraction rate of the effective components from the salt mud reaches 97.5%. The Ca content in the second mixed solution... 2+ Mg 2+ The concentrations were 1.05 mol / L and 0.28 mol / L, respectively. Calculations showed that the effect on Ca in the salt mud was... 2+ Mg 2+ The extraction rates were 99.99% and 92.0%, respectively; the Ca in the fourth mixed solution 2+ Mg 2+ The concentrations were 0.175 mmol / L and 0.047 mmol / L, respectively. Calculations show that Ca... 2+ Mg 2+ The precipitation rates were 99.9% and 99.9% respectively; the mass of the environmentally friendly calcium magnesium acetate snow-melting corrosion inhibitor was 20.58g, and the product yield was calculated to be 99.9%; the whiteness of the environmentally friendly calcium magnesium acetate snow-melting corrosion inhibitor was 98.5; and the water content in the alcohol precipitation solution was 0.05%.

[0077] Depend on Figure 1 It is known that the environmentally friendly snow melting corrosion inhibitor containing calcium acetate and magnesium acetate contains diffraction peaks. Therefore, the product obtained by this preparation method is calcium acetate. Example 4

[0078] (1) The solid phase in the salt mud was crushed into 450 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 1625mL of pure water was added and mixed evenly to prepare a slurry. 7.0g of allyl polyoxyalkyl epoxy ether and 210g of 1-propylamino-3-butylimidazolium tetrafluoroborate were added to the slurry and mixed evenly to obtain the first mixed solution.

[0079] (2) Add 9.0 mol of 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 the residue and the second mixed solution;

[0080] (3) Prepare an alcohol precipitation solution by mixing methanol and methyl acetate in a volume ratio of 1:3.5. Take 100 mL of the second mixed solution and add 400 mL of alcohol precipitation solution to the second mixed solution to carry out the alcohol precipitation reaction. Control the alcohol precipitation temperature at 40℃, the alcohol precipitation time at 0.6 h, and the stirring rate at 400 r / min to obtain the third mixed solution.

[0081] (4) The third mixed solution is centrifuged to obtain crude calcium magnesium acetate environmentally friendly snow melting corrosion inhibitor and the fourth mixed solution. The crude calcium magnesium acetate environmentally friendly snow melting corrosion inhibitor is vacuum dried at 55℃ for 1.0h to obtain calcium magnesium acetate environmentally friendly snow melting corrosion inhibitor. The fourth mixed solution is distilled under reduced pressure in a distillation tower. A mixture of gaseous methanol, methyl acetate and water is obtained at the top. The mixture of gaseous methanol, 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.

[0082] (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 4.0% of the mass of the fifth mixed solution, the adsorption time is 0.8h, and the stirring speed is 200r / min. After filtration, 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.

[0083] In step (2), the residue was dried and weighed. The weighing results are shown in Table 1.

[0084] In step (2), the second mixed solution undergoes ICP Ca2+ ionization. 2+ Mg 2+ Concentration testing was conducted using the same method as in Example 1, and the results are shown in Table 1.

[0085] In step (4), the fourth mixed solution is subjected to ICP Ca2+. 2+ Mg 2+Concentration testing was conducted using the same method as in Example 1, and the results are shown in Table 1.

[0086] The XRD structure, yield, and whiteness of the calcium magnesium acetate environmentally friendly snow-melting corrosion inhibitor in step (4) were tested using the same methods as in Example 1. The test results are shown in [Figure 1]. Figure 1 Table 1.

[0087] Table 1 shows that the mass of the dried residue was 66.82 g. Calculations indicate that the utilization rate of the salt mud was 86.64%, and the extraction rate of the effective components from the salt mud reached 96.8%. The Ca content in the second mixed solution... 2+ Mg 2+ The concentrations were 1.16 mol / L and 0.30 mol / L, respectively. Calculations showed that the effect on Ca in the salt mud... 2+ Mg 2+ The extraction rates were 99.99% and 89.0%, respectively; the Ca in the fourth mixed solution 2+ Mg 2+ The concentrations were 1.39 mmol / L and 0.24 mmol / L, respectively. Calculations show that Ca... 2+ Mg 2+ The precipitation rates were 99.4% and 99.6%, respectively; the mass of the environmentally friendly calcium magnesium acetate snow-melting corrosion inhibitor was 22.51g, and the product yield was calculated to be 99.50%; the whiteness of the environmentally friendly calcium magnesium acetate snow-melting corrosion inhibitor was 98.5; and the water content in the alcohol precipitation solution was 0.15%.

[0088] Depend on Figure 1 It is known that the environmentally friendly snow melting corrosion inhibitor containing calcium acetate and magnesium acetate contains diffraction peaks. Therefore, the product obtained by this preparation method is calcium acetate. Example 5

[0089] (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. 7.5g of allyl alcohol polyoxyalkyl ether and 150g of 1-(2-aminoethyl)-2-methylpyrazole bromide were added to the slurry and mixed evenly to obtain the first mixed solution.

[0090] (2) Add 9.0 mol of 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 the residue and the second mixed solution;

[0091] (3) Prepare an alcohol precipitation solution by mixing ethanol and acetone in a volume ratio of 1:4. Take 100 mL of the second mixed solution and add 200 mL of the alcohol precipitation solution to the second mixed solution to carry out the alcohol precipitation reaction. Control the alcohol precipitation temperature at 50℃, the alcohol precipitation time at 1.0 h, and the stirring rate at 500 r / min to obtain the third mixed solution.

[0092] (4) The third mixed solution is centrifuged to obtain crude calcium magnesium acetate environmentally friendly snow melting corrosion inhibitor and the fourth mixed solution. The crude calcium magnesium acetate environmentally friendly snow melting corrosion inhibitor is vacuum dried at 45°C for 1.5h to obtain calcium magnesium acetate environmentally friendly snow melting corrosion inhibitor. The fourth mixed solution is distilled under reduced pressure in a distillation tower. A mixture of gaseous ethanol, acetone and water is obtained at the top. The mixture of gaseous ethanol, acetone 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.

[0093] (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 4.5% of the mass of the fifth mixed solution, the adsorption time is 0.8h, 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 140℃ for 3h and then regenerated for recycling.

[0094] The residue in step (2) was dried and weighed. The weighing results are shown in Table 1.

[0095] In step (2), the second mixed solution undergoes ICP Ca2+ ionization. 2+ Mg 2+ Concentration testing was conducted using the same method as in Example 1, and the results are shown in Table 1.

[0096] In step (4), the fourth mixed solution is subjected to ICP Ca2+. 2+ Mg 2+ Concentration testing was conducted using the same method as in Example 1, and the results are shown in Table 1.

[0097] The XRD structure, yield, and whiteness of the calcium magnesium acetate environmentally friendly snow-melting corrosion inhibitor in step (4) were tested using the same methods as in Example 1. The test results are shown in [Figure 1]. Figure 1 Table 1.

[0098] Table 1 shows that the mass of the dried residue was 66.37 g. Calculations indicate that the utilization rate of the salt mud was 86.73%, and the extraction rate of the effective components from the salt mud reached 96.9%. The Ca content in the second mixed solution... 2+ Mg 2+ The concentrations were 1.49 mol / L and 0.39 mol / L, respectively. Calculations showed that the effect on Ca in the salt mud...2+ Mg 2+ The extraction rates were 99.99% and 89.0%, respectively; the Ca in the fourth mixed solution 2+ Mg 2+ The concentrations were 9.93 mmol / L and 0.91 mmol / L, respectively. Calculations show that Ca... 2+ Mg 2+ The precipitation rates were 98.0% and 99.3%, respectively; the mass of the environmentally friendly calcium magnesium acetate snow-melting corrosion inhibitor was 28.69 g, and the product yield was calculated to be 98.50%; the whiteness of the environmentally friendly calcium magnesium acetate snow-melting corrosion inhibitor was 98.5; and the water content in the alcohol precipitation solution was 0.08%.

[0099] Depend on Figure 1 It is known that the environmentally friendly snow melting corrosion inhibitor containing calcium acetate and magnesium acetate contains diffraction peaks. Therefore, the product obtained by this preparation method is calcium acetate. Comparative Example 1

[0100] 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, while the other steps remain the same.

[0101] During the experiment, it was found that when the ratio of dry-balanced salt mud to water in the slurry was less than 1 g: 2 mL, after adding acetic acid, the reaction lasted for about 10 minutes, and the entire reaction system became a viscous solid agglomerate, making acidification impossible. The reason for the formation of this viscous solid agglomerate state is that the acetic acid reacts 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 produced in the reaction absorbs 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 a stirred acidification reaction impossible, and the utilization rate of the salt mud is zero. Therefore, controlling the amount of water is a crucial factor in determining whether the acidification reaction can proceed; the amount of water must be appropriately controlled. Comparative Example 2

[0102] 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, while the other steps remain the same.

[0103] 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.

[0104] As shown in Table 1, the mass of the environmentally friendly calcium magnesium acetate snow-melting corrosion inhibitor is 4.79 g. Calculations show that the product yield is 65.11%. This indicates that excessive use of pure water, under the same conditions, will lead to a decrease in the product yield. Comparative Example 3

[0105] 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.

[0106] During the experiment, it was found that without the addition of acidifying aids, the acidification reaction was violent, producing large amounts of carbon dioxide gas bubbles that caused salt mud and solution to overflow, making the reaction dangerous. Therefore, acidifying aids are a key factor in ensuring the safe and gentle conduct of the acidification reaction. Comparative Example 4

[0107] 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.

[0108] During the experiment, it was found that without the addition of acidifying agents and ionic liquids, the reactants turned into viscous solid agglomerates. This is because the vigorous reaction between acetic acid and calcium carbonate in the salt mud generates a large amount of heat and carbon dioxide bubbles. The large amount of heat carries away some water, and the calcium acetate and magnesium acetate 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 the bubbles to combine with the salt mud to form viscous solid agglomerates, making the acidification reaction impossible. Therefore, ionic liquids and acidifying agents are necessary prerequisites for the acidification reaction to proceed. Comparative Example 5

[0109] The difference between Comparative Example 5 and Example 1 is that in step (1), 162.5g of ionic liquid 1-propylamino-3-butylimidazolium tetrafluoroborate is replaced with 162.5g of pure water and glacial acetic acid is added dropwise in step (2), while other operation steps remain unchanged.

[0110] In step (2), the residue was dried and weighed. The weighing results are shown in Table 1.

[0111] In step (2), the second mixed solution undergoes ICP Ca2+ ionization. 2+ Mg 2+ Concentration testing was conducted using the same method as in Example 1, and the results are shown in Table 1.

[0112] In step (4), the fourth mixed solution is subjected to ICP Ca2+. 2+ Mg 2+ Concentration testing was conducted using the same method as in Example 1, and the results are shown in Table 1.

[0113] The yield of the environmentally friendly calcium magnesium acetate snow melting corrosion inhibitor in step (4) was tested using the same method as in Example 1. The test results are shown in Table 1.

[0114] Table 1 shows that the residue mass is 66.82g. Calculations indicate that the utilization rate of the salt mud is 86.64%, and the extraction rate of the effective components from the salt mud is 96.90%. The Ca content in the second mixed solution... 2+ Mg 2+ With concentrations of 1.50 mol / L and 0.40 mol / L, respectively, calculations show that the effect on Ca in the salt mud... 2+ Mg 2+ The extraction rates were 99.9% and 90.0%, respectively; the Ca in the fourth mixed solution 2+ Mg 2+ The concentrations were 40.50 mmol / L and 10.80 mmol / L, respectively. Calculations show that Ca... 2+ Mg 2+ The precipitation rates were 89.2% and 89.2% respectively; the mass of the environmentally friendly calcium magnesium acetate de-icing corrosion inhibitor was 26.25g, and the calculated product yield was 89.2%. This indicates that ionic liquids can affect the addition rate of glacial acetic acid. This is because during the acidification reaction, the amino or azole functional groups (i.e., nitrogen sites) of the ionic liquid can absorb carbon dioxide, reducing the likelihood of large bubbles being generated; ionic liquids also affect the reaction rate of Ca... 2+ Mg 2+ The precipitation rate, which is the decrease in Ca2+ concentration in the reaction solution due to the presence of ionic liquids during alcohol precipitation. 2+ Mg 2+ The solubility of [the substance] increases the efficiency of alcohol precipitation. Comparative Example 6

[0115] The difference between Comparative Example 6 and Example 1 is that the amount of acetic acid added in step (1) is different. The amount of acetic acid added is changed from 8.5 mol to 5.0 mol, while the other operation steps remain unchanged.

[0116] In step (2), the residue was dried and weighed. The weighing results are shown in Table 1.

[0117] In step (2), the second mixed solution undergoes ICP Ca2+ ionization. 2+ Mg 2+ Concentration test results are shown in Table 1.

[0118] In step (4), the fourth mixed solution is subjected to ICP Ca2+. 2+ Mg 2+ Concentration testing was conducted using the same method as in Example 1, and the results are shown in Table 1.

[0119] The yield of the environmentally friendly calcium magnesium acetate snow melting corrosion inhibitor in step (4) was tested using the same method as in Example 1. The test results are shown in Table 1.

[0120] Table 1 shows that the mass of the residue after drying is 256.11 g. Calculations indicate that the utilization rate of the salt mud is 48.78%, and the extraction rate of the effective components from the salt mud reaches 54.5%. The Ca content in the second mixed solution... 2+ Mg 2+ The concentrations were 0.872 mol / L and 0.228 mol / L, respectively. Calculations show that the effect on Ca in the salt mud... 2+ Mg 2+ The extraction rates were 51.50% and 45.90%, respectively; the Ca in the fourth mixed solution 2+ Mg 2+ The concentrations were 42.51 mmol / L and 11.11 mmol / L, respectively. Calculations show 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 indicates that when the amount of acetic acid added is small, it affects not only the acidification efficiency but also the alcohol precipitation efficiency. Comparative Example 7

[0121] The difference between Comparative Example 7 and Example 1 is that the alcohol precipitation reaction conditions in step (4) are different. The alcohol precipitation temperature is changed from 45°C to 80°C, while the other operation steps remain unchanged.

[0122] During the alcohol precipitation reaction, it was found that when the precipitation temperature exceeds 60℃, the reaction solution rapidly transforms into a gel state. This is because at excessively high temperatures, calcium and magnesium acetate particles in the solution rapidly nucleate, grow, and precipitate. These particles also adhere to each other, causing the solution to become gel-like, making it difficult to remove the material and thus hindering industrial-scale production. Therefore, it is crucial to appropriately control the temperature of the alcohol precipitation reaction. Comparative Example 8

[0123] 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, while the other operation steps remain unchanged.

[0124] During the alcohol precipitation reaction, it was found that when the stirring speed was below 300 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. Comparative Example 9

[0125] The difference between Comparative Example 9 and Example 1 is that steps (3)-(5) are omitted. The specific operation steps are as follows:

[0126] Take 100 mL of the second mixed solution, place it in a beaker and seal it with tin foil. Evaporate the moisture in a forced-air drying oven at 90-110℃. After evaporation for 12 hours, you will obtain calcium magnesium acetate environmentally friendly snow melting corrosion inhibitor.

[0127] The yield and whiteness of the environmentally friendly calcium magnesium acetate snow melting corrosion inhibitor were tested using the same method as in Example 1. The test results are shown in Table 1.

[0128] As shown in Table 1, the mass of the product was 29.42 g. Calculations show a yield of 100% and a whiteness of 90.5. Compared to the whiteness of Example 1, the whiteness of Comparative Example 9 in Example 1 is 1.09 times higher. This is because the solution contains Fe. 3+ Impurity ions or air oxidation can cause a decrease in whiteness, but the alcohol precipitation method does not require consideration of Fe. 3+ The influence of impurity ions reduces the number of operation steps and lowers process operating costs. Furthermore, the alcohol precipitation method in Example 1 takes 48 minutes, while the evaporation and concentration method in Comparative Example 9 takes 720 minutes. Example 1 is 15 times faster than Comparative Example 9, demonstrating that the alcohol precipitation method can also significantly save time and reduce energy consumption. Comparative Example 10

[0129] The difference between Comparative Example 10 and Example 1 is that the salt mud was not crushed in step (1), while the other steps remained the same.

[0130] In step (2), the residue was dried and weighed. The weighing results are shown in Table 1.

[0131] As shown in Table 1, the residue was 363.51g. Calculations show that the utilization rate of the salt mud was 27.30%, far lower than the effect of Example 1. This is because large pieces of salt mud are difficult to acidify. Therefore, the crushing of the salt mud is a key factor in the acidification reaction. Comparative Example 11

[0132] The difference between Comparative Example 11 and Example 1 is that the particle size of the salt mud crushed in step (1) is different. The particle size of the solid phase in the salt mud is 1200 mesh, while the other steps remain unchanged.

[0133] In step (2), the residue was dried and weighed. The weighing results are shown in Table 1.

[0134] During the experiment, we found that some salt mud floated on the surface. This was because prolonged crushing caused the material to heat up rapidly, moisture to evaporate, and the mass of individual salt mud particles to decrease, making them easy to float. This resulted in the salt mud not reacting with acetic acid in time, and consequently, the utilization rate of the salt mud decreased.

[0135] As shown in Table 1, the residue was 113.522g. Calculations indicate that the utilization rate of the salt mud was 77.30%, far lower than the effect of Example 1. Therefore, controlling the particle size of the salt mud is also a key factor in the acidification reaction.

[0136]

[0137] As shown above, comparing Comparative Examples 1-2 and Example 1 reveals that a dry-based ratio of salt mud to water of less than 1g:2mL or greater than 1g:4mL affects both the acidification and alcohol precipitation reactions. When the dry-based ratio is less than 1g:2mL, the solution forms viscous solid agglomerates. When the dry-based ratio is greater than 1g:4mL, the concentration of the calcium magnesium acetate solution decreases, leading to a decrease in the precipitation effect of the alcohol precipitation reaction under the same conditions, thus affecting the precipitation efficiency. Therefore, the amount of pure water used should be appropriately controlled. Comparing Comparative Example 3 and Example 1 shows that the acidification aid can suppress the generation of large carbon dioxide bubbles, dispersing them into smaller bubbles and preventing solution overflow, which is a key factor for the safe and gentle conduct of the acidification reaction. Comparative Example 4 and Example 1 show that the ionic liquid and the acidification aid have a synergistic effect and can also prevent the solution from becoming viscous solid agglomerates, which is a key factor for maintaining a gentle acidification reaction. A comparison of Comparative Example 5 and Example 1 shows that ionic liquids can absorb carbon dioxide, reduce the likelihood of large bubbles forming, and have a synergistic effect with acidifying agents, promoting the one-time addition of acetic acid and accelerating the acidification reaction process. Simultaneously, ionic liquids also affect the absorption of Ca... 2+ Mg 2+ The precipitation rate is crucial; therefore, ionic liquids are an indispensable condition for the entire reaction process. A comparison between Comparative Example 6 and Example 1 shows that a small amount of acetic acid affects both acidification and alcohol precipitation efficiency; therefore, the amount of acetic acid added must be appropriately controlled. A comparison between Comparative Examples 7-8 and Example 1 shows that both the alcohol precipitation temperature and stirring speed affect the alcohol precipitation effect; therefore, the alcohol precipitation reaction conditions must be appropriately controlled. A comparison between Comparative Example 9 and Example 1 shows that the traditional method of preparing environmentally friendly calcium magnesium acetate desiccant corrosion inhibitor by evaporation and concentration is not only time-consuming and produces low whiteness, but also energy-intensive. A comparison between Comparative Examples 10-11 and Example 1 shows that a particle size of 200-500 mesh for crushing salt mud is another key factor in the acidification reaction.

Claims

1. A method for preparing an environmentally friendly calcium magnesium acetate snow-melting corrosion inhibitor through comprehensive utilization of chlor-alkali salt mud solid waste, characterized in that, Includes 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. 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) Acetic acid is added to the first mixed solution in one go under stirring, and the reaction is carried out at 25-85℃ for 1-4 hours. After separation, the residue and the second mixed solution are obtained. (3) Prepare an alcohol precipitation solution by mixing water-soluble alcohol organic solvents with ketone organic solvents or ester organic solvents, 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 calcium magnesium acetate environmentally friendly snow melting corrosion inhibitor and the fourth mixed solution; the crude calcium magnesium acetate environmentally friendly snow melting corrosion inhibitor is dried to obtain calcium magnesium acetate environmentally friendly snow melting corrosion inhibitor; the fourth mixed solution is distilled under reduced pressure to obtain a gaseous mixture of water-soluble alcohol organic solvent, ketone organic solvent or ester organic solvent and water at the top; the mixture of water-soluble alcohol organic solvent, ketone organic solvent or ester organic solvent and water is condensed to obtain the 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.

2. The method for preparing calcium magnesium acetate environmentally friendly snow-melting corrosion inhibitor through comprehensive utilization of chlor-alkali salt mud 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 0.003-0.008g:1mL; the ratio of the amount of ionic liquid added to the total amount of water in the first mixed solution is 0.1-0.15g:1mL.

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

4. 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 organic solvent is either methanol or ethanol; the ketone organic solvent is acetone; and the ester organic solvent is either ethyl acetate or methyl acetate.

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

1.

6. The method for preparing calcium magnesium acetate environmentally friendly snow-melting corrosion inhibitor through 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℃, alcohol precipitation time 0.5-1h, and stirring speed 300-600r / min.

7. The method for preparing calcium magnesium acetate environmentally friendly snow-melting corrosion inhibitor through comprehensive utilization of chlor-alkali salt mud 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.

8. The method for preparing calcium magnesium acetate environmentally friendly snow-melting corrosion inhibitor through comprehensive utilization of chlor-alkali salt mud 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 2-5% of the mass of the fifth mixed solution, the adsorption time is 0.5-1h, and the stirring speed is 200-300r / min.

9. The method for preparing calcium magnesium acetate environmentally friendly snow-melting corrosion inhibitor through comprehensive utilization of chlor-alkali salt mud 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.

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