A CMA environmentally friendly de-icing agent prepared from magnesite tailings and waste acetic acid, its preparation method and application

Abstract

This invention provides a CMA environmentally friendly de-icing agent prepared from magnesite tailings and waste acetic acid, along with its preparation method and application. Belonging to the field of industrial solid waste treatment and utilization technology, it includes the following raw materials in parts by weight: 50-60 parts magnesite tailings, 40-80 parts waste acetic acid, 5-10 parts glacial acetic acid, 20-50 parts calcium oxide, and 1-5 parts magnesium oxide. By co-utilizing two industrial wastes—difficult-to-treat magnesite tailings and industrial waste acetic acid—a high-performance, low-corrosion CMA de-icing agent is prepared without deep purification. This achieves low-cost resource utilization of industrial waste and produces a competitive, environmentally friendly de-icing agent product, simultaneously solving multiple industrial and environmental problems such as solid waste accumulation, waste acid disposal, and the high cost and pollution of de-icing agents.

Description

Technical Field

[0001] This invention belongs to the field of industrial solid waste treatment and utilization technology, specifically relating to a CMA environmentally friendly de-icing agent prepared from magnesite tailings and waste acetic acid, its preparation method, and its application. Background Technology

[0002] The large quantities of low-grade ore and tailings generated during the mining and processing of magnesite resources in my country, due to their low magnesium and calcium grades and high impurity content, have long lacked economically feasible large-scale high-value utilization methods. Most of these have been stockpiled, not only occupying land resources but also posing environmental safety risks such as dust, leachate pollution, and slope stability. Meanwhile, large quantities of industrial waste acetic acid, a byproduct of the chemical, pharmaceutical, and chemical fiber industries, typically have low acetic acid concentrations, complex compositions, and high refining and purification costs. It is mostly treated as waste liquid for neutralization, increasing the environmental burden on enterprises and resulting in resource waste.

[0003] Snow-melting agents are essential materials for snow removal and ensuring smooth traffic in winter. Currently, the market is dominated by chloride-based products such as sodium chloride and calcium chloride. Although these snow-melting agents are inexpensive and have high snow-melting efficiency, their strong corrosiveness can severely erode roads, bridges, vehicle chassis, and reinforced concrete structures, leading to long-term ecological and environmental problems such as soil salinization, groundwater pollution, and vegetation death. In practice, their use comes with high hidden environmental costs.

[0004] CMA, as an internationally recognized environmentally friendly de-icing agent, has advantages such as being chlorine-free, low-corrosion, and biodegradable, thus avoiding the corrosion and pollution problems caused by chloride salts at the source. However, traditional CMA production relies on glacial acetic acid and high-purity calcium magnesium carbonate / oxides, resulting in high raw material costs and high prices, making large-scale promotion difficult.

[0005] In the existing technology, CMA environmentally friendly de-icing agents have the following defects: First, some technologies still rely on high-purity chemicals or specific biomass derivatives such as wood vinegar, which limits the source of raw materials and is costly; Second, the formulation and preparation process of some chlorine-free de-icing agents are relatively complex, which is not conducive to industrial production; Third, some products still fail to completely eliminate chloride salts and cannot completely solve the problems of corrosion and pollution. Summary of the Invention

[0006] Based on the above-mentioned technical problems, the purpose of this invention is to provide a CMA environmentally friendly de-icing agent prepared from magnesite tailings and waste acetic acid, as well as its preparation method and application. By co-utilizing two industrial wastes, namely the difficult-to-treat magnesite tailings and industrial waste acetic acid, a high-performance, low-corrosion CMA de-icing agent is prepared without deep purification. This achieves the resource utilization of industrial waste at low cost and produces a competitive environmentally friendly de-icing agent product, simultaneously solving multiple industrial and environmental problems such as solid waste accumulation, waste acid disposal, and the high cost and high pollution of de-icing agents.

[0007] The specific technical solution is as follows: A CMA environmentally friendly de-icing agent prepared using magnesite tailings and waste acetic acid. The de-icing agent comprises the following raw materials in parts by weight: 50-60 parts by weight of magnesite tailings, 40-80 parts by weight of waste acetic acid, 5-10 parts by weight of glacial acetic acid, 20-50 parts by weight of calcium oxide, and 1-5 parts by weight of magnesium oxide.

[0008] In addition, the CMA environmentally friendly de-icing agent prepared from magnesite tailings and waste acetic acid in the above-mentioned technical solution provided by the present invention may also have the following additional technical features: In the above technical solution, the waste acetic acid is at least one of the distillation residues or washing waste liquids from chemical fiber, pharmaceutical, wood processing or acetate production processes; the acetic acid content in the waste acetic acid is 20% to 40%, and it contains organic impurities, metal ions and suspended solids, and is not purified by distillation before use.

[0009] In the above technical solution, the de-icing agent is a white to slightly yellow powder, and its 5% aqueous solution has a pH of 6.5 to 7.5. The content of magnesium acetate is 48% to 56%, the content of calcium acetate is 18% to 22%, and the mass ratio of magnesium acetate to calcium acetate is 7:3 to 8:3.

[0010] In the above technical solution, the carbon steel corrosion rate of the de-icing agent is 0.08~0.09 mm / a, and it has a snow-melting function in an environment of -15℃.

[0011] A method for preparing CMA environmentally friendly de-icing agent includes the following steps: S1: Pretreatment of magnesite tailings by crushing, screening and washing, and analysis of magnesium and calcium content; S2: Based on the analysis results of step S1, calcium oxide and / or magnesium oxide are added to the pretreated magnesite tailings to adjust the mass ratio of magnesium acetate to calcium acetate in the final snow melting agent to be 7:3~8:3. S3: Add the material obtained in step S2 and waste acetic acid into the reactor at a mass ratio of 1:7 to 1:4, and carry out the acid hydrolysis reaction under heating and stirring conditions; S4: During the reaction, glacial acetic acid is added to adjust the pH value to 6.5~7.5. After the reaction is completed, a milky white viscous liquid is obtained. S5: CMA environmentally friendly de-icing agent is obtained by filtration, washing, drying and pulverizing a milky white viscous liquid.

[0012] In the above technical solution, the pretreatment includes crushing and finely grinding the magnesite tailings to 100-200 mesh, removing impurities by vibrating screen, and then washing, pressing and dewatering to a moisture content of ≤5%.

[0013] In the above technical solution, in step S3, the acid hydrolysis reaction temperature is 80~150℃, the heating rate is 2~5℃ / min, the reaction time is 1~2h, the stirring speed is 100~150r / min, and the stirring time is 30~40min.

[0014] Application of CMA environmentally friendly de-icing agent in de-icing and snow removal on roads, bridges, or airports.

[0015] The present invention discloses a CMA environmentally friendly de-icing agent prepared from magnesite tailings and waste acetic acid, its preparation method, and its application. Compared with the prior art, the advantages are as follows: 1. By co-utilizing two industrial wastes—difficult-to-process magnesite tailings and industrial waste acetic acid—a high-performance, low-corrosion CMA de-icing agent was prepared without deep purification. This not only enables the high-value utilization of resources but also reduces the environmental pressure caused by solid waste accumulation and waste acid emissions at the source, achieving waste resource recovery.

[0016] 2. By precisely controlling the ratio of magnesium acetate to calcium acetate in the product to remain stable within the optimal range of 7:3 to 8:3, and by controlling the reaction to be completed under near-neutral conditions, combined with the appropriate dilution effect of inert impurities in the raw materials, the resulting CMA de-icing agent exhibits low metal corrosivity. Its carbon steel corrosion rate is only 0.08~0.09 mm / a, which is about 46% lower than that of traditional CMA process and more than 80% lower than that of sodium chloride, significantly enhancing its protective effect on roads, bridges, vehicles, and reinforced concrete structures.

[0017] 3. This de-icing agent maintains its high-efficiency ice-melting capacity even at temperatures as low as -15℃, and its low-temperature adaptability is significantly better than that of chloride-based products, ensuring its reliability in extremely cold regions.

[0018] 4. The process flow of this invention is clear, and the main steps are conventional operations such as crushing, acid hydrolysis, filtration and drying. The reaction conditions are mild and controllable, and there is no need for complex distillation purification of waste acetic acid. The equipment requirements are low, and it is easy to achieve continuous and large-scale production, with high industrialization feasibility.

[0019] 5. This invention simultaneously solves four major industry pain points: solid waste accumulation, waste acid treatment, corrosive pollution from de-icing agents, and high costs. Attached Figure Description

[0020] Figure 1 This is a flowchart illustrating the preparation of the CMA environmentally friendly de-icing agent according to the present invention. Detailed Implementation

[0021] The following are specific implementation cases and appendices. Figure 1 The present invention will be further described, but the present invention is not limited to these embodiments.

[0022] A CMA environmentally friendly de-icing agent prepared using magnesite tailings and waste acetic acid. The de-icing agent comprises the following raw materials in parts by weight: 50-60 parts by weight of magnesite tailings, 40-80 parts by weight of waste acetic acid, 5-10 parts by weight of glacial acetic acid, 20-50 parts by weight of calcium oxide, and 1-5 parts by weight of magnesium oxide.

[0023] In embodiments of the present invention, the waste acetic acid is at least one of the distillation residues or washing waste liquids from chemical fiber, pharmaceutical, wood processing or acetate production processes; the acetic acid content in the waste acetic acid is 20% to 40%, and it contains organic impurities, metal ions and suspended solids, and is not purified by distillation before use.

[0024] Specifically, the typical composition of industrial waste acetic acid includes: 20%~40% acetic acid, 55%~75% H2O, 0.5%~3% small molecule organic acids, 0.2%~2% alcohols / esters / aldehydes, 500~2000ppm metal ions, and 0.1%~1% suspended solids.

[0025] The factory produces its own waste acetic acid, which is taken from the process where acetic acid is used as a solvent / reaction medium. After being allowed to settle and coarsely filtered to remove suspended solids, it is used directly without distillation, concentration, or decolorization, thus achieving low-cost on-site disposal of waste acid.

[0026] In embodiments of the present invention, the de-icing agent is a white to slightly yellow powder, the pH of its 5% aqueous solution is 6.5 to 7.5, the content of magnesium acetate is 48% to 56%, the content of calcium acetate is 18% to 22%, the total effective acetate is 70% to 78%, the water-insoluble matter is 18% to 26%, and the crystal morphology is weakly crystalline / amorphous; the mass ratio of magnesium acetate to calcium acetate is 7:3 to 8:3.

[0027] In the embodiments of the present invention, the carbon steel corrosion rate of the de-icing agent is 0.08~0.09 mm / a, and it has a de-icing function at -15℃; it reduces corrosion rate by about 46% compared to traditional pure CMA and by more than 80% compared to NaCl.

[0028] A method for preparing CMA environmentally friendly de-icing agent includes the following steps: S1: Pretreatment of magnesite tailings by crushing, screening and washing, and analysis of magnesium and calcium content; S2: Based on the analysis results of step S1, calcium oxide and / or magnesium oxide are added to the pretreated magnesite tailings to adjust the mass ratio of magnesium acetate to calcium acetate in the final snow melting agent to be 7:3~8:3. S3: Add the material obtained in step S2 and waste acetic acid into the reactor at a mass ratio of 1:7 to 1:4, and carry out the acid hydrolysis reaction under heating and stirring conditions; S4: During the reaction, glacial acetic acid is added to adjust the pH value to 6.5~7.5. After the reaction is completed, a milky white viscous liquid is obtained. S5: CMA environmentally friendly de-icing agent is obtained by filtration, washing, drying and pulverizing a milky white viscous liquid.

[0029] The milky white viscous liquid obtained in step S4 can be used as an anti-icing material and evenly applied to the surface of the target material.

[0030] The CMA environmentally friendly de-icing agent obtained in step S5 is a white to slightly yellow powder. Sprinkle the powder evenly on the snow surface to achieve the effect of snow removal and ice breaking.

[0031] Magnesite tailings mainly consist of carbonates such as MgCO3, CaCO3, and CaMg(CO3)2. They undergo a liquid-solid heterogeneous acidolysis reaction with acetic acid, a spontaneously exothermic reaction in which CO2 escapes and drives the reaction in the forward direction. The carbonates in magnesite undergo an acidolysis reaction with acetic acid: MgCO3+2CH3COOH → Mg(CH3COO)2+H2O+CO2↑ CaCO3+2CH3COOH → Ca(CH3COO)2+H2O+CO2↑ Small amounts of MgO and CaO in the tailings undergo a neutralization reaction, transforming into magnesium acetate and calcium acetate. SiO2 and Al2O3 in the system are inert and insoluble substances that do not participate in the reaction; they are ultimately partially removed or moderately retained through solid-liquid separation.

[0032] In an embodiment of the present invention, the pretreatment includes crushing and finely grinding the magnesite tailings to 100-200 mesh, removing impurities by vibrating screen, and then washing, pressing, filtration and dewatering until the moisture content is ≤5%.

[0033] The tailings are coarsely crushed by a jaw crusher and then finely ground to 100-200 mesh by wet grinding in a ball mill to increase the surface area and acid lysis conversion rate. Quartz, silicates and other difficult-to-acid-lyse coarse particles are removed by vibrating screen. Stirring, washing and pressure filtration are performed to dewater and reduce mud and soluble impurities. The moisture content after pretreatment is ≤5%, ensuring stable and controllable reaction.

[0034] In an embodiment of the present invention, in step S3, the acid hydrolysis reaction temperature is 80~150℃, the heating rate is 2~5℃ / min, the reaction time is 1~2h, the stirring speed is 100~150r / min, and the stirring time is 30~40min.

[0035] Application of CMA environmentally friendly de-icing agent in de-icing and snow removal on roads, bridges, or airports.

[0036] CMA environmentally friendly de-icing agent can be used as a liquid spray, a solid spreader, and as an anti-icing coating material as a substrate. Example 1

[0037] The magnesite tailings studied in this embodiment came from Laizhou, Shandong Province, and their main chemical composition is shown in Table 1: Table 1. Composition of tailings from a magnesite mine in Laizhou, Shandong Province Element MgO CaO <![CDATA[SiO2]]> <![CDATA[Al2O3]]> Loss on ignition other content 42.70 4.85 6.10 0.75 44.32 1.28 As shown in Table 1, the total amount of MgO+CaO is high, but the calcium-magnesium ratio fluctuates greatly and contains inert impurities. It belongs to low-quality solid waste that is difficult to directly utilize at a high value. It must be adjusted by elemental supplementation to obtain the optimal CMA performance.

[0038] This example provides a method for preparing CMA environmentally friendly de-icing agent using magnesite tailings and waste acetic acid as raw materials. The raw material components include: Magnesite tailings, 50 parts by weight; waste acetic acid, 50 parts by weight; glacial acetic acid, 5 parts by weight; calcium oxide, 50 parts by weight.

[0039] The preparation method of the CMA environmentally friendly de-icing agent in this embodiment includes the following steps: S1: Take 50 parts by weight of magnesite tailings, calcium oxide and waste acetic acid; S2: Add 50 parts by weight of calcium oxide to optimize the elemental ratio in magnesite tailings; S3: Add magnesite tailings and waste acetic acid to the reactor. The reactor is heated at a rate of 5℃ / min, with a maximum temperature of 120℃. S4: Stirring speed 120 rad / min, stirring time 40 min, reaction time 1.5 h; S5: Add 5 parts by weight of glacial acetic acid to adjust the pH to 6.5; S6: After the reaction is complete, a milky white viscous liquid is obtained; S7: After filtration, washing, drying, and pulverizing, a milky white powder is obtained, which is CMA environmentally friendly de-icing agent.

[0040] The performance parameters of the CMA environmentally friendly de-icing agent obtained in Example 1 were determined in accordance with the national standard "GB / T23851-2017".

[0041] 1. Relative snow melting capacity: Snow melting performance test: At -10℃, the snow melting agent and the traditional NaCl-type snow melting agent were evenly sprayed onto a unit volume of snow. The snow melting efficiency of the snow melting agent was tested by the amount of snow that could be melted by the snow melting agent per unit time. The results are as follows: Table 2 Comparison of snow melting efficiency between the snow melting agent of this invention and NaCl-type snow melting agents type 5min 10min 15min Calcium magnesium acetate de-icing agent Melt 45% Melt 70% All melted NaCl-type snow melting agent 47% melted Melt 75% All melted As shown in Table 2, the snow melting efficiency of this de-icing agent is basically comparable to that of traditional NaCl-type de-icing agents, but it has more significant advantages over the latter: The de-icing agent prepared by this method has low corrosiveness to highway infrastructure and will not cause water and soil pollution, thus exhibiting green and environmentally friendly characteristics. It is a new technology that turns tailings into valuable resources, and it is of great significance for the effective utilization of biomass resources.

[0042] 2. pH value of CMA de-icing agent: The standard value specified in the national standard "GB / T23851-2017" is 6.0-10.0. The pH value of the CMA de-icing agent in this invention is 6.5, which complies with the national standard.

[0043] 3. Impacts on soil and plants: Soil was soaked and leached with traditional NaCl-type de-icing agent and this CMA de-icing agent, respectively. The leaching solution was NaCl-type de-icing agent and CMA de-icing agent with a mass fraction of 3% and 5%, respectively. After each leaching, the different heavy metal forms and contents in the soil were measured to investigate the effects of the two de-icing agents on the typical heavy metal binding states in the soil.

[0044] The results showed that, compared with CMA de-icing agent, NaCl-type de-icing agent had a more significant impact on soil heavy metals, and the impact increased with the increase of the NaCl de-icing agent mass ratio; CMA de-icing agent was more environmentally friendly.

[0045] 4. Corrosion rate of carbon steel: This experiment used 200 g / L NaCl-type de-icing agent and this CMA de-icing agent to determine the corrosion degree of carbon steel at the same concentration. The corrosion rates of 200 g / L sodium chloride and 200 g / L CMA on carbon steel were 0.446 mm / a and 0.087 mm / a, respectively. The corrosion rate of this CMA de-icing agent was reduced by 80% compared to the NaCl-type de-icing agent.

[0046] The national standard "GB / T23851-2017" specifies a carbon steel corrosion rate of ≤0.11mm / a. The carbon steel corrosion rate of the CMA environmentally friendly de-icing agent in this invention is 0.01mm / a, which meets the national requirements. Example 2

[0047] The magnesite studied in this embodiment is an ore sourced from Haicheng, Liaoning Province, and its main chemical composition is shown in Table 3. Table 3. Composition of tailings from a magnesite mine in Haicheng, Liaoning Province Element w(MgO) w(CaO) <![CDATA[w(SiO2)]]> <![CDATA[w(Al2O3)]]> Loss on ignition other content 32.17 16.59 5.89 0.91 43.13 1.31 This example provides a method for preparing CMA environmentally friendly de-icing agent using magnesite tailings and waste acetic acid as raw materials. The raw material components include: Magnesite tailings, 50 parts by weight; waste acetic acid, 50 parts by weight; glacial acetic acid, 5 parts by weight; calcium oxide, 35 parts by weight.

[0048] The preparation method of the CMA environmentally friendly de-icing agent in this embodiment includes the following steps: S1: Take 50 parts by weight of magnesite tailings, calcium oxide and waste acetic acid; S2: Add 35 parts by weight of calcium oxide to optimize the elemental ratio in magnesite tailings; S3: Add magnesite tailings and waste acetic acid to the reactor. The reactor is heated at a rate of 5℃ / min, with a maximum temperature of 140℃. S4: Stirring speed 120 rad / min, stirring time 40 min, reaction time 2 h; S5: Add 5 parts by weight of glacial acetic acid to adjust the pH to 6.8; S6: After the reaction is complete, a milky white viscous liquid is obtained; S7: After filtration, washing, drying, and pulverizing, a milky white powder is obtained, which is CMA environmentally friendly de-icing agent.

[0049] The performance parameters of the CMA environmentally friendly de-icing agent obtained in Example 2 were determined according to the national standard "GB / T23851-2017".

[0050] 1. Relative snow melting capacity: Snow melting performance test: At -10℃, the snow melting agent and the traditional NaCl-type snow melting agent were evenly sprayed onto a unit volume of snow. The snow melting efficiency of the snow melting agent was tested by the amount of snow that could be melted by the snow melting agent per unit time. The results are as follows: Table 4 Comparison of snow melting efficiency between the snow melting agent of this invention and NaCl-type snow melting agents type 5min 10min 15min Calcium magnesium acetate de-icing agent Melt 45% Melt 70% All melted NaCl-type snow melting agent 47% melted Melt 75% All melted As shown in Table 4, the snow melting efficiency of this de-icing agent is basically comparable to that of traditional NaCl-type de-icing agents, but it has more significant advantages over the latter: 2. pH value of CMA de-icing agent: The standard value specified in the national standard "GB / T23851-2017" is 6.0-10.0. The pH value of the CMA de-icing agent in this invention is 6.8, which complies with the national standard.

[0051] 3. Impacts on soil and plants: Soil was soaked and leached with traditional NaCl-type de-icing agent and this CMA de-icing agent, respectively. The leaching solution was NaCl-type de-icing agent and CMA de-icing agent with a mass fraction of 3% and 5%, respectively. After each leaching, the different heavy metal forms and contents in the soil were measured to investigate the effects of the two de-icing agents on the typical heavy metal binding states in the soil.

[0052] The results showed that, compared with CMA de-icing agent, NaCl-type de-icing agent had a more significant impact on soil heavy metals, and the impact increased with the increase of the NaCl de-icing agent mass ratio; CMA de-icing agent was more environmentally friendly.

[0053] 4. Corrosion rate of carbon steel: This experiment used 200 g / L NaCl-type de-icing agent and this CMA de-icing agent to determine the corrosion degree of carbon steel at the same concentration. The corrosion rates of 50 g / L sodium chloride and 50 g / L CMA on carbon steel were 0.774 mm / a and 0.188 mm / a, respectively. The corrosion rate of this CMA de-icing agent was reduced by 80% compared with that of the NaCl-type de-icing agent.

[0054] The national standard "GB / T23851-2017" specifies a carbon steel corrosion rate of ≤0.11mm / a. The carbon steel corrosion rate of the CMA environmentally friendly de-icing agent in this invention is 0.01mm / a, which meets the national requirements. Example 3

[0055] The basis and experimental data for the magnesium acetate:calcium acetate ratio of 7:3~8:3 are as follows: Table 5. Effects of different formulation ratios on CMA performance <![CDATA[Mg(Ac)2:Ca(Ac)2]]> Freezing point (°C) Snow melting time at -10℃ (min) Corrosion rate of carbon steel (mm / a) Solubility / hygroscopicity 5:5 -12.5 22 0.12 generally 6:4 -14.2 18 0.1 better 7:3 -15.8 14 0.085 excellent 7.5:2.5 -16.1 13 0.082 excellent 8:2 -15.3 15 0.090 Moisture-absorbing 9:1 -13.7 19 0.11 Moisture-absorbing Conclusion: The 7:3 to 8:3 range exhibits the lowest freezing point, fastest snow melting, lowest corrosion, and best storage and transportation performance. Excessive magnesium content leads to moisture absorption and increased corrosion; excessive calcium content raises the freezing point and reduces efficiency.

[0056] Table 6 Results of Process Parameter Optimization heating rate 2~5℃ / min reaction temperature 80~150℃ Liquid-to-solid ratio (acid:mineral) 4:1~7:1 reaction time 1~2h Stirring speed 100~150r / min endpoint pH 6.5~7.5 After optimization: acid hydrolysis conversion rate ≥92%, effective acetate yield ≥88%, suitable for industrial continuous production.

[0057] Table 7 Physicochemical Properties of CMA Snow Melting Agent Appearance In liquid form, it is a milky white viscous liquid; in solid form, it is a white to slightly yellow powder with good flowability. phase of matter Weakly crystalline / amorphous complex salt, XRD shows no strong sharp peaks (distinguishing it from pure CMA). Active ingredient (HPLC / titration) Magnesium acetate: 48%–56%; Calcium acetate: 18%–22%; Total available acetate: 70%–78%. Water-insoluble matter (inert impurities) 18%~26% Moisture content (after drying) ≤1.5% 5% aqueous solution pH 6.5~7.5 Low corrosion core mechanism Inert insoluble substances moderately dilute the concentration of active salts, reducing ionic strength and electrochemical corrosion; near-neutral pH prevents concrete erosion; trace organic components in waste acetic acid form a weakly adsorbed protective film; a specific 7:3 to 8:3 ratio synergistically reduces corrosivity. Table 8 Comparison of snow melting performance at different temperatures (equal dosage: 100g / m²) 2 ) sample Melting time at -5℃ (min) Melting time at -10℃ (min) Melting time at -15℃ (min) This invention CMA 8 14 25 Traditional Pure CMA 9 16 28 NaCl 7 15 >60 Conclusion: Under conditions ranging from room temperature to -10℃, the snow melting efficiency of the CMA of this invention is comparable to that of NaCl and superior to that of traditional pure CMA. At a low temperature of -15℃, the snow melting efficiency of NaCl drops sharply, while the CMA of this invention can still melt ice efficiently, demonstrating significantly better low-temperature adaptability than chloride salts.

[0058] Table 9 Comparison of Corrosion Rates sample Corrosion rate of carbon steel (mm / a) CMA is lower than that of pure CMA Lower than NaCl This invention 0.08-0.09 ≈46% ≈82% Pure CMA (Traditional Craftsmanship) 0.14-0.16 —— ≈70% NaCl 0.45-0.75 —— —— The solid waste-based CMA prepared by this invention has a significantly lower corrosion rate than traditional CMA and NaCl. Its advantage is not achieved through raw material purification, but rather through the synergistic effect of solid waste route + ratio control + near-neutral synthesis, which has outstanding technical non-obviousness.

[0059] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A CMA environmentally friendly de-icing agent prepared from magnesite tailings and waste acetic acid, characterized in that, The de-icing agent comprises the following raw materials in parts by weight: 50-60 parts by weight of magnesite tailings, 40-80 parts by weight of waste acetic acid, 5-10 parts by weight of glacial acetic acid, 20-50 parts by weight of calcium oxide, and 1-5 parts by weight of magnesium oxide.

2. The CMA environmentally friendly de-icing agent prepared from magnesite tailings and waste acetic acid according to claim 1, characterized in that, The waste acetic acid is at least one of the distillation residues or washing waste liquids from chemical fiber, pharmaceutical, wood processing or acetate production processes; the acetic acid content in the waste acetic acid is 20% to 40%, it contains organic impurities, metal ions and suspended solids, and it is not purified by distillation before use.

3. The CMA environmentally friendly de-icing agent prepared from magnesite tailings and waste acetic acid according to claim 2, characterized in that, The de-icing agent is a white to slightly yellow powder, and its 5% aqueous solution has a pH of 6.5 to 7.

5. The content of magnesium acetate is 48% to 56%, the content of calcium acetate is 18% to 22%, and the mass ratio of magnesium acetate to calcium acetate is 7:3 to 8:

3.

4. The CMA environmentally friendly de-icing agent prepared from magnesite tailings and waste acetic acid according to claim 3, characterized in that, The de-icing agent has a carbon steel corrosion rate of 0.08~0.09 mm / a and has a de-icing function at -15℃.

5. A method for preparing the CMA environmentally friendly de-icing agent as described in any one of claims 1-4, characterized in that, Includes the following steps: S1: Pretreatment of magnesite tailings by crushing, screening and washing, and analysis of magnesium and calcium content; S2: Based on the analysis results of step S1, calcium oxide and / or magnesium oxide are added to the pretreated magnesite tailings to adjust the mass ratio of magnesium acetate to calcium acetate in the final snow melting agent to be 7:3~8:

3. S3: Add the material obtained in step S2 and waste acetic acid into the reactor at a mass ratio of 1:7 to 1:4, and carry out the acid hydrolysis reaction under heating and stirring conditions; S4: During the reaction, glacial acetic acid is added to adjust the pH value to 6.5~7.

5. After the reaction is completed, a milky white viscous liquid is obtained. S5: CMA environmentally friendly de-icing agent is obtained by filtration, washing, drying and pulverizing a milky white viscous liquid.

6. The method according to claim 5, characterized in that, The pretreatment includes crushing and finely grinding the magnesite tailings to 100-200 mesh, removing impurities by vibrating screen, and then washing, filtration and dewatering until the moisture content is ≤5%.

7. The method according to claim 5, characterized in that, In step S3, the acid hydrolysis reaction temperature is 80~150℃, the heating rate is 2~5℃ / min, the reaction time is 1~2h, the stirring speed is 100~150r / min, and the stirring time is 30~40min.

8. The application of the CMA environmentally friendly de-icing agent according to any one of claims 1-4 in de-icing and snow removal on roads, bridges or airports.

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