A surfactant for steel slag-derived calcium carbonate and a method for preparing the same

Abstract

The application discloses a kind of steel slag derived calcium carbonate with surfactant and its preparation method, it is related to surfactant field.The surfactant includes: the mass ratio of 3~6:4~7 fatty acid salt and polyether modified polyvinyl phenol;The polyether modified polyvinyl phenol first takes vinyl phenol as comonomer, carries out free radical copolymerization in inert atmosphere, and the molecular weight of vinyl phenol polymer prepared is 1000~10000;Vinyl phenol polymer is made to be ring-opening polymerization with ethylene oxide gas under catalyst, and it is obtained;The molar ratio of vinyl phenol and ethylene oxide is 1:5~15.The surfactant of the application can effectively solve the problem that high oil absorption value steel slag derived calcium carbonate is poor in stability in aqueous system, and is easy to agglomerate and precipitate.

Description

Technical Field

[0001] This application relates to the field of surfactants, and in particular to a surfactant for steel slag-derived calcium carbonate and a method for preparing the same. Background Technology

[0002] Precipitated calcium carbonate is an important industrial filler due to its excellent whitening properties.

[0003] With its enhanced properties and low cost, calcium carbonate is widely used in coatings, plastics, rubber, papermaking, and other fields. Traditional calcium carbonate production relies on limestone calcination, which not only consumes large amounts of mineral resources but also results in significant carbon emissions and environmental damage. In recent years, the technology of using calcium sources from industrial solid wastes such as steel slag to prepare precipitated calcium carbonate through carbonation reactions has attracted much attention. This technology can achieve both the resource utilization of solid waste and the reduction of greenhouse gas emissions through carbon capture, resulting in significant environmental and economic benefits.

[0004] However, the complex composition of steel slag and the poor matching between the calcium source release rate and carbonation conditions make it difficult to precisely control the nucleation and growth process of the generated calcium carbonate crystals, resulting in problems such as wide crystal size distribution and irregular morphology. The uneven distribution of surface energy due to large differences in crystal size, coupled with the influence of residual iron, magnesium, and other impurity ions in steel slag, makes the oil absorption value of the product significantly higher than that of traditional calcium carbonate (typically reaching 40-80 mL / 100g). When this type of calcium carbonate is used in water-based coatings or adhesives, particle aggregation is prone to occur, and conventional dispersants are unable to form a stable adsorption layer on the crystal surface. During storage, stratification and sedimentation often occur, severely restricting its application.

[0005] While existing technologies have attempted to improve dispersibility by adding polycarboxylate or phosphate dispersants, their molecular structures are not well-suited to the high specific surface area and multiple active sites of calcium carbonate in steel slag. They cannot effectively inhibit crystal re-agglomeration, and excessive addition can easily lead to an abnormal increase in system viscosity, affecting coating performance. Summary of the Invention

[0006] To address the problem that steel slag-derived calcium carbonate is difficult to maintain stability in aqueous systems during long-term storage and is prone to agglomeration and precipitation, this application provides a surfactant for steel slag-derived calcium carbonate and its preparation method.

[0007] In a first aspect, this application provides a surfactant for steel slag-derived calcium carbonate, comprising:

[0008] Fatty acid salts and polyether-modified polyvinylphenol in a mass ratio of 3-6:4-7;

[0009] The polyether-modified polyvinylphenol is first prepared by free radical copolymerization of vinylphenol as a comonomer in an inert atmosphere to obtain a vinylphenol polymer with a molecular weight of 1,000 to 10,000; then the vinylphenol polymer is subjected to ring-opening polymerization with ethylene oxide gas under a catalyst to obtain the final product; the molar ratio of vinylphenol to ethylene oxide is 1:5 to 15.

[0010] The structural formula of the polyether-modified polyvinylphenol described in this application is as follows:

[0011]

[0012] Where R is -(CH2CH2O) m H, m = 5~15.

[0013] In any of the above technical solutions, the catalyst is tin tetrachloride.

[0014] In any of the above technical solutions, the amount of catalyst used is 1.0 to 2.0 wt% of vinylphenol.

[0015] In any of the above technical solutions, the ring-opening polymerization temperature is 80-100℃ and the pressure is 0.05-0.1MPa.

[0016] It is worth noting that ethylene oxide is prone to self-polymerization or decomposition at temperatures above 100°C, which is not conducive to chain growth control.

[0017] In any of the above technical solutions, the molecular weight of the vinylphenol polymer is 2000 to 5000.

[0018] Vinylphenol polymers with molecular weights controlled between 1000 and 10000 are suitable for calcium carbonate dispersion. When the molecular weight is below 1000, the polymer chain is too short, resulting in insufficient anchoring points and easy desorption; when it is above 10000, the molecular chain rigidity increases, making it difficult to adapt to the particle surface morphology, and the adsorption capacity decreases. The molecular weight range of 2000 to 5000 gives the polymer moderate flexibility and outstanding adsorption effect.

[0019] It is worth noting that the molecular weight of the vinylphenol polymer in this application can be determined by gel permeation chromatography and viscosity method.

[0020] In any of the above technical solutions, the vinylphenol polymer is pretreated before the ring-opening polymerization, specifically by vacuum dehydrating the polymer until the water content is less than 1%.

[0021] In this application, polyether-modified polyvinylphenol exhibits a strong affinity between its main vinylphenol unit and high oil absorption value steel slag-derived calcium carbonate. The polyether segments in the side chains form a steric barrier on the particle surface through hydration, significantly reducing particle agglomeration and effectively dispersing the steel slag-derived calcium carbonate particles. The synergistic effect of fatty acid salts and polyether chains further enhances the stability of the adsorption layer. Fatty acid salts preferentially adsorb onto high surface energy sites, while polyether chains cover low-energy regions. This complementary coating improves the surface energy uniformity of particles of different sizes.

[0022] In any of the technical solutions, the fatty acid salt is selected from sodium stearate, potassium stearate, sodium oleate, sodium laurylate, or ammonium stearate.

[0023] In any of the above technical solutions, the raw materials for the free radical copolymerization reaction further include an alkenyl sulfonate, wherein the amount of the alkenyl sulfonate is 2-5 wt% of vinylphenol.

[0024] In any of the above technical solutions, the alkenyl sulfonate is selected from one or more of sodium vinyl sulfonate, sodium styrene sulfonate, sodium methacrylate sulfonate, and sodium allyl sulfonate.

[0025] In any of the above technical solutions, the method for preparing the vinylphenol polymer is as follows: vinylphenol and an alkenyl sulfonate are dissolved in a solvent, heated to 65-75°C under a nitrogen atmosphere, an initiator solution is added dropwise, the reaction time is 2-4 hours, hydroquinone is added to terminate the reaction; the solution is dropped into cold methanol to precipitate, filtered, and then vacuum dried to obtain the polymer.

[0026] In any of the above technical solutions, the amount of the initiator is 2 to 5% of the mass of the comonomer.

[0027] In any of the above technical solutions, the amount of hydroquinone used is 0.1 to 0.3% of the mass of vinylphenol.

[0028] The introduction of alkenyl sulfonate increases the negative charge density on the particle surface due to the strong ionization properties of the sulfonic acid groups, enhancing electrostatic repulsion and significantly improving the stability of the dispersion system. Simultaneously, the sulfonic acid groups form an amphiphilic structure with the polyether chains. At low temperatures, the hydrophilicity of the sulfonic acid groups dominates, allowing the polymer to fully extend; as the temperature rises, the dehydration shrinkage of the polyether chains is offset by the hydration of the sulfonic acid groups. This improved temperature responsiveness allows the dispersant to maintain a stable adsorption conformation within the temperature range of 5–80°C.

[0029] Secondly, this application provides a method for preparing a surfactant for steel slag-derived calcium carbonate, comprising: mixing polyether-modified polyvinylphenol with a fatty acid salt according to the proportion of any of the surfactants described above, and stirring until homogeneous.

[0030] In summary, this application has the following beneficial effects:

[0031] This application utilizes the synergistic effect of fatty acid salts and polyether-modified polyvinylphenol to form a multi-layered dispersion system. The fatty acid salts rapidly adsorb, reducing surface energy differences, while the polymer grafted with polyether chains inhibits aggregation through a steric barrier. The introduction of sulfonic acid groups enhances both electrostatic stability and temperature adaptability, while also raising the cloud point. Detailed Implementation

[0032] Example

[0033] Example 1: A surfactant for steel slag-derived calcium carbonate. 40g of ammonium stearate and 60g of polyether-modified polyvinylphenol were mixed and stirred at 50°C for 2 hours to obtain a uniform paste.

[0034] Polyether-modified polyvinylphenol is prepared according to the following steps:

[0035] Preparation of vinylphenol polymers

[0036] Dissolve 500g of vinylphenol and 15g of sodium styrene sulfonate in 600mL of tetrahydrofuran, and purge with nitrogen three times to remove dissolved oxygen.

[0037] The temperature was raised to 70℃, and 50 mL of ethanol solution containing 15 g of azobisisobutyronitrile was added dropwise at a rate of 10 mL / min. The reaction was maintained at this temperature for 3 hours. The reaction was terminated by adding 1.25 g of hydroquinone, and the mixture was cooled to room temperature. The reaction solution was slowly added dropwise to 4 L of cold methanol to precipitate the product. After filtration, the product was washed three times with methanol and dried under vacuum at 60℃ for 12 hours to obtain a vinylphenol polymer with an average molecular weight of approximately 3600.

[0038] Preparation of polyether-modified polyvinylphenol

[0039] The dried vinylphenol polymer was placed in a high-pressure reactor and dehydrated under vacuum at 100°C until the water content reached 0.8%. 7.5 g of tin tetrachloride was added, and ethylene oxide gas was introduced at a molar ratio of (vinylphenol: ethylene oxide) of 1:10. The reaction was maintained at 95°C for 8 hours under a pressure of 0.08 MPa. After the reaction was completed, the mixture was cooled to 50°C, and after depressurization, polyether-modified polyvinylphenol (m=10) was obtained.

[0040] Example 2: A surfactant for steel slag-derived calcium carbonate. 30g of sodium oleate and 70g of polyether-modified polyvinylphenol were mixed and stirred at 60°C for 1 hour to obtain a uniform paste.

[0041] Polyether-modified polyvinylphenol is prepared according to the following steps:

[0042] Preparation of vinylphenol polymers

[0043] Dissolve 300g of vinylphenol and 6g of sodium vinyl sulfonate in 400mL of toluene, and purge with nitrogen three times to remove dissolved oxygen.

[0044] The temperature was raised to 65℃, and 30 mL of acetone solution containing 6 g of benzoyl peroxide was added dropwise at a rate of 10 mL / min. The reaction was maintained at this temperature for 4 hours. The reaction was terminated by adding 0.9 g of hydroquinone, and the mixture was cooled to room temperature. The reaction solution was slowly added dropwise to 4 L of cold methanol to precipitate the product. After filtration, the product was washed three times with methanol and dried under vacuum at 60℃ for 12 hours to obtain a vinylphenol polymer with an average molecular weight of approximately 2000.

[0045] Preparation of polyether-modified polyvinylphenol

[0046] The dried vinylphenol polymer was placed in a high-pressure reactor and dehydrated under vacuum at 105°C until the water content reached 0.5%. 6g of tin tetrachloride was added, and ethylene oxide gas was introduced at a molar ratio of (vinylphenol:ethylene oxide) 1:15. The reaction was maintained at 100°C for 6 hours under a pressure of 0.05 MPa. After the reaction was completed, the mixture was cooled to 50°C, and after depressurization, polyether-modified polyvinylphenol (m=15) was obtained.

[0047] Example 3: A surfactant for steel slag-derived calcium carbonate. 60g of sodium stearate and 40g of polyether-modified polyvinylphenol were mixed and stirred at 40°C for 2 hours to obtain a uniform paste.

[0048] Polyether-modified polyvinylphenol is prepared according to the following steps:

[0049] Preparation of vinylphenol polymers

[0050] Dissolve 700g of vinylphenol and 35g of sodium styrene sulfonate in 800mL of tetrahydrofuran, and purge with nitrogen three times to remove dissolved oxygen.

[0051] The temperature was raised to 75℃, and a 70mL ethanol solution containing 30g of azobisisobutyronitrile was added dropwise at a rate of 5mL / min. The reaction was maintained at this temperature for 2 hours. The reaction was terminated by adding 0.8g of hydroquinone, and the mixture was cooled to room temperature. The reaction solution was slowly added dropwise to 5L of cold methanol to precipitate the product. After filtration, the product was washed three times with methanol and dried under vacuum at 60℃ for 12 hours to obtain a vinylphenol polymer with an average molecular weight of approximately 5000.

[0052] Preparation of polyether-modified polyvinylphenol

[0053] The dried vinylphenol polymer was placed in a high-pressure reactor and dehydrated under vacuum at 100°C until the water content reached 0.9%. 7.0 g of tin tetrachloride was added, and ethylene oxide gas was introduced at a molar ratio of (vinylphenol:ethylene oxide) 1:5. The reaction was maintained at 82°C for 10 hours under a pressure of 0.1 MPa. After the reaction was completed, the mixture was cooled to 50°C, and after depressurization, polyether-modified polyvinylphenol (m=5) was obtained.

[0054] Example 4, a surfactant for steel slag-derived calcium carbonate, differs from Example 1 in that an equal mass of vinylphenol is used instead of sodium styrene sulfonate.

[0055] Example 5: A surfactant for steel slag-derived calcium carbonate. 40g of ammonium stearate and 60g of polyether-modified polyvinylphenol were mixed and stirred at 50°C for 2 hours to obtain a uniform paste.

[0056] Polyether-modified polyvinylphenol is prepared according to the following steps:

[0057] Preparation of vinylphenol polymers

[0058] Dissolve 500g of vinylphenol and 15g of sodium styrene sulfonate in 600mL of tetrahydrofuran, and purge with nitrogen three times to remove dissolved oxygen.

[0059] The temperature was raised to 75℃, and 50 mL of ethanol solution containing 25 g of azobisisobutyronitrile was added dropwise at a rate of 15 mL / min. The reaction was maintained at this temperature for 2 hours. The reaction was terminated by adding 1.25 g of hydroquinone, and the mixture was cooled to room temperature. The reaction solution was slowly added dropwise to 4 L of cold methanol to precipitate the product. After filtration, the product was washed three times with methanol and dried under vacuum at 60℃ for 12 hours to obtain a vinylphenol polymer with an average molecular weight of approximately 1200.

[0060] The preparation of polyether-modified polyvinylphenol is the same as in Example 1.

[0061] Example 6: A surfactant for steel slag-derived calcium carbonate. 40g of ammonium stearate and 60g of polyether-modified polyvinylphenol were mixed and stirred at 50°C for 2 hours to obtain a uniform paste.

[0062] Polyether-modified polyvinylphenol is prepared according to the following steps:

[0063] Preparation of vinylphenol polymers

[0064] Dissolve 500g of vinylphenol and 15g of sodium styrene sulfonate in 600mL of tetrahydrofuran, and purge with nitrogen three times to remove dissolved oxygen.

[0065] The temperature was raised to 65℃, and 50 mL of ethanol solution containing 10 g of azobisisobutyronitrile was added dropwise at a rate of 5 mL / min. The reaction was maintained at this temperature for 4 hours. The reaction was terminated by adding 1.25 g of hydroquinone, and the mixture was cooled to room temperature. The reaction solution was slowly added dropwise to 4 L of cold methanol to precipitate the product. After filtration, the product was washed three times with methanol and dried under vacuum at 60℃ for 12 hours to obtain a vinylphenol polymer with an average molecular weight of approximately 9600.

[0066] The preparation of polyether-modified polyvinylphenol is the same as in Example 1.

[0067] Comparative Example

[0068] Comparative Example 1, a surfactant for steel slag-derived calcium carbonate, differs from Example 1 in that it uses an equal mass of polyether-modified polyvinylphenol instead of ammonium stearate.

[0069] Comparative Example 2, a surfactant for steel slag-derived calcium carbonate, differs from Example 1 in that it replaces polyether-modified polyvinylphenol with an equal mass of ammonium stearate.

[0070] Comparative Example 3, a surfactant for steel slag-derived calcium carbonate, differs from Example 1 in that an equal mass of isomeric alcohol polyether surfactant (Pluronic PE6100) replaces polyether-modified polyvinylphenol.

[0071] Comparative Example 4, a surfactant for steel slag-derived calcium carbonate, differs from Example 1 in that an equal mass of sodium polycarboxylate (DP5040) replaces polyether-modified polyvinylphenol and ammonium stearate.

[0072] Performance testing

[0073] Experiment 1: Surfactant Stability Test

[0074] Sample preparation: Ten groups of steel slag-derived calcium carbonate (D50 particle size 2μm, oil absorption value 60mL / 100g) of the same specification were taken as samples. The samples and steel slag-derived calcium carbonate were mixed evenly with surfactant and water, and then polyvinyl alcohol (PVA1788) was added. The mixture was stirred at 500rpm for 1h to obtain the samples. The mass ratio of surfactant, steel slag-derived calcium carbonate, polyvinyl alcohol and water was 5:20:10:65.

[0075] Test method: (1) The particle size and particle size distribution of the sample were detected by Malvern laser particle size analyzer. The initial average particle size and particle size distribution uniformity (PDI) were measured. After being placed at room temperature (23±2℃) for 3 months, the average particle size was measured again.

[0076] (2) After placing the sample in a constant temperature environment of 5°C for 1 month, measure its average particle size.

[0077] (3) After placing the sample in a constant temperature environment of 80℃ for 1 month, measure its average particle size.

[0078] Table 1. Stability Test Results

[0079]

[0080] As can be seen from Examples 1 to 6 and Comparative Examples 1 to 4, and Table 1, the polyether-modified polyvinylphenol and fatty acid salts used in this application can effectively promote the dispersion of steel slag-derived calcium carbonate and inhibit its agglomeration and sedimentation. It can maintain good storage stability when stored for a long time in the temperature range of 5-80℃, and no obvious agglomeration and sedimentation phenomenon is observed.

[0081] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A surfactant for steel slag-derived calcium carbonate, characterized in that, include: Fatty acid salts and polyether-modified polyvinylphenol in a mass ratio of 3-6:4-7; The polyether-modified polyvinylphenol is first prepared by free radical copolymerization of vinylphenol and alkenyl sulfonate as comonomers in an inert atmosphere to obtain a vinylphenol polymer with a molecular weight of 1,000 to 10,000; wherein the amount of alkenyl sulfonate is 2 to 5 wt% of vinylphenol; then the vinylphenol polymer is subjected to ring-opening polymerization with ethylene oxide gas under a catalyst to obtain the final product; the molar ratio of vinylphenol to ethylene oxide is 1:5 to 15. The alkenyl sulfonate is selected from one or more of sodium vinyl sulfonate, sodium styrene sulfonate, sodium methacrylate sulfonate, and sodium allyl sulfonate; The fatty acid salt is selected from sodium stearate, potassium stearate, sodium oleate, sodium laurate, or ammonium stearate; The method for preparing the vinylphenol polymer is as follows: vinylphenol and alkenyl sulfonate are dissolved in a solvent, heated to 65-75°C under a nitrogen atmosphere, an initiator solution is added dropwise, the reaction time is 2-4 hours, hydroquinone is added to terminate the reaction; the solution is dropped into cold methanol to precipitate, filtered, and then vacuum dried to obtain the polymer.

2. The surfactant according to claim 1, characterized in that, The catalyst is tin tetrachloride.

3. The surfactant according to claim 2, characterized in that, The catalyst is used in an amount of 1.0 to 2.0 wt% of vinylphenol.

4. The surfactant according to claim 1, characterized in that, The ring-opening polymerization is carried out at a temperature of 80–100°C and a pressure of 0.05–0.1 MPa.

5. The surfactant according to claim 1, characterized in that, The molecular weight of the vinylphenol polymer is 2000-5000.

6. The surfactant according to claim 1, characterized in that, The amount of the initiator is 2 to 5% of the total mass of the comonomer.

7. A method for preparing a surfactant for steel slag-derived calcium carbonate as described in any one of claims 1 to 6, characterized in that, The polyether-modified polyvinylphenol and fatty acid salt are mixed in the specified ratio and stirred until homogeneous to obtain the final product.

Images