CN115806402B - Special high-dispersion plastic-retaining polycarboxylate superplasticizer for phosphogypsum and preparation method thereof - Google Patents
Special high-dispersion plastic-retaining polycarboxylate superplasticizer for phosphogypsum and preparation method thereof Download PDFInfo
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Abstract
The invention provides a special high-dispersion plastic-retaining polycarboxylate water reducer for phosphogypsum and a preparation method thereof, wherein the water reducer comprises an unsaturated polyether macromonomer, unsaturated carboxylic acid, tetrahydrophthalic anhydride acylated amino-terminated polyether monomer, an unsaturated phosphoric monoester functional monomer, an initiator, a molecular weight regulator and water, wherein the solid content of a finished product mother solution of the polycarboxylate water reducer is 49-51%, and the pH value is 10.0-13.0. The polycarboxylate water reducer aims at solving the problems that the initial fluidity of gypsum self-leveling mortar is smaller, the fluidity loss is overlarge in 30min, the absolute dry fracture resistance and compressive strength of 24h and 28d are low and the standard requirements cannot be met due to the poor adaptability of the existing water reducer and phosphogypsum materials. The polycarboxylate water reducer has more remarkable dispersion effect on phosphogypsum systems, better plasticity retention and higher strength, and solves the problems of unobvious dispersion effect, poor plasticizing effect, low strength, poor adaptability and the like of the traditional polycarboxylate water reducer on phosphogypsum systems.
Description
Technical Field
The invention belongs to the technical field of building material additives, and particularly relates to a special high-dispersion plastic-retaining polycarboxylate superplasticizer for phosphogypsum and a preparation method thereof.
Background
Phosphogypsum is solid waste generated in the wet-process phosphoric acid process, and according to incomplete statistics, the total piling amount of phosphogypsum in China is more than 6 hundred million tons, and the annual production amount is 7500 ten thousand tons, a large amount of phosphogypsum is still piled up, not only occupies a large amount of land, but also causes environmental problems such as atmospheric, water system and soil pollution. Phosphogypsum is mainly composed of dihydrate gypsum, the content of which can reach 70-90%, and the phosphogypsum is acidic, and contains 20% -25% of free water, and besides, the phosphogypsum also contains a small amount of harmful substances such as phosphoric acid, silicon, magnesium, iron, aluminum, fluoride, organic impurities and the like. Phosphogypsum mainly has two colors of gray black and gray white, the particle diameter is generally 5-50 mu m, and the bulk density reaches 1000kg/m 3 . Phosphogypsum has the characteristics of strong viscosity, high temperature resistance and chemical corrosion resistance, and has the greatest advantages of high strength and good toughness.
The gypsum-based self-leveling mortar is also called self-leveling gypsum and self-leveling ground leveling gypsum, and is a dry powder mortar special for indoor ground leveling, which is prepared by carefully preparing and uniformly mixing gypsum materials, special fillers and various building chemical additives in factories. The phosphogypsum is utilized to replace natural gypsum to prepare the gypsum-based self-leveling material, so that waste can be changed into valuable, the method is an effective way for comprehensively utilizing resources, not only can the precious gypsum resources in industrial byproducts be fully utilized, but also the problem of environmental pollution caused by phosphogypsum can be solved, and the method has good economic benefit and market development prospect. Compared with natural gypsum, phosphogypsum contains a plurality of harmful impurities such as phosphorus, fluorine, organic matters and the like, and the components, colors, phosphorus residual amounts and the like of phosphogypsum of different production places are greatly different. The traditional polycarboxylate water reducer has poor dispersibility on phosphogypsum-based self-leveling slurry, large flow rate loss with time, low strength and poor adaptability, and can not meet the standard requirements, thereby greatly restricting the application of the polycarboxylate water reducer in phosphogypsum-based self-leveling materials.
In summary, as the adaptability problem of the industrial byproduct phosphogypsum and the polycarboxylate water reducer causes small initial fluidity of the phosphogypsum self-leveling mortar, the 30min fluidity loss is too large, and the 24h and 28d absolute dry fracture-resistant compressive strength is low and can not meet the standard requirements, the development of the high-dispersion plastic-retaining polycarboxylate water reducer special for the phosphogypsum with good adaptability is urgently needed, and the method has great practical significance for promoting the industrialization, the greenization and the high-efficiency utilization of the phosphogypsum.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides a special high-dispersion plastic-retaining polycarboxylate superplasticizer for phosphogypsum and a preparation method thereof, and aims to solve the problems that the initial fluidity of gypsum self-leveling mortar is smaller, the fluidity loss is overlarge in 30min, the absolute dry fracture-resistant compressive strength of 24h and 28d is low and can not meet the standard requirements due to the poor adaptability of the existing superplasticizer and phosphogypsum materials. The polycarboxylate water reducer has more remarkable dispersion effect on phosphogypsum systems, better plasticity retention and higher strength, overcomes the problems of unobvious dispersion effect, poor plasticizing effect, low strength, poor adaptability and the like of the traditional polycarboxylate water reducer on phosphogypsum systems, belongs to a pure green additive, has simple production equipment and process and mild reaction conditions, and has great significance in promoting industrialization, greenization and high-efficiency utilization of phosphogypsum.
In order to achieve the above purpose, the technical scheme adopted by the invention for solving the technical problems is as follows:
the special high-dispersion plastic-retaining polycarboxylate water reducer for phosphogypsum comprises an unsaturated polyether macromonomer, unsaturated carboxylic acid, tetrahydrophthalic anhydride acylated amino-terminated polyether monomer, an unsaturated phosphoric monoester functional monomer, an initiator, a molecular weight regulator and water, wherein the mass ratio of the unsaturated polyether macromonomer, the unsaturated carboxylic acid, the tetrahydrophthalic anhydride acylated amino-terminated polyether monomer, the unsaturated phosphoric monoester functional monomer, the initiator and the molecular weight regulator is 340-370:20-35:5-10:3-8:2.5-5:1.0-3.5, the solid content of the finished product mother solution of the polycarboxylate water reducer is 49-51%, and the pH value is 10.0-13.0.
Further, the tetrahydrophthalic anhydride acylated amino-terminated polyether monomer is prepared by the following method: dissolving tetrahydrophthalic anhydride and amine-terminated polyether in an organic solvent, heating to 70-120 ℃ under stirring, adding a catalyst into the mixture, carrying out an acylation reaction for 5-8h under heat preservation, and removing the organic solvent after the reaction is finished to obtain the modified polyamide.
Further, the molar ratio of the tetrahydrophthalic anhydride to the amino-terminated polyether is 1.0-1.1:1; the catalyst is one or two of anhydrous aluminum trichloride, trifluoroacetic acid, 4-dimethylaminopyridine, benzenesulfonic acid, methanesulfonic acid, sulfamic acid and p-toluenesulfonic acid, and the dosage of the catalyst is 2.0-5.0% of the total mass of tetrahydrophthalic anhydride and amino-terminated polyether; the organic solvent is at least one of ethyl acetate, N-dimethylformamide, N-dimethylacetamide, toluene and acetone, and the dosage of the organic solvent accounts for 5-25% of the total mass percent of the material.
Further, the amino-terminated polyether is a polyether diamine compound terminated by amino or amino, and the molecular weight of the amino-terminated polyether is 100-1000.
Further, the amine-terminated polyether includes at least one of triethylene glycol diamine, tripropylene glycol diamine, polyoxyethylene diamine, polyoxypropylene diamine, polyoxyethylene-polyoxypropylene copolyether diamine, and polytetramethylene ether diamine.
Further, the unsaturated phosphate monoester functional monomer is prepared by the following method: mixing N-hydroxyalkyl acrylamide and polyphosphoric acid, heating to 50-70 ℃ for phosphating reaction for 4-6h, adding water into the mixture, heating to 60-80 ℃ for hydrolysis reaction for 1.5-3h, and obtaining the N-hydroxyalkyl acrylamide.
Further, the molar ratio of the N-hydroxyalkyl acrylamide to the polyphosphoric acid is 1:1.0-1.1; the N-hydroxyalkyl acrylamide comprises one of N-methylolacrylamide, N-hydroxyethyl acrylamide, N- (3-hydroxypropyl) acrylamide, N- (4-hydroxybutyl) acrylamide, N-methylolmethacrylamide, N- (2-hydroxyethyl) methacrylamide and N- (2-hydroxypropyl) methacrylamide; the polyphosphoric acid comprises at least one of tripolyphosphoric acid, tetraphosphoric acid, pentaphosphoric acid and hexaphosphoric acid, and the industrial grade content is 105-118% (calculated by mass fraction of phosphoric acid).
Further, the polyphosphoric acid was tetraphosphoric acid having an industrial grade content of 115% (in terms of phosphoric acid mass fraction).
Further, the unsaturated polyether macromonomer is ethylene glycol monovinyl polyoxyethylene ether and/or methallyl alcohol polyoxyethylene ether, and the molecular weight of the unsaturated polyether macromonomer is 3000-5000; the unsaturated carboxylic acid is at least one of acrylic acid, methacrylic acid, 3-dimethyl acrylic acid, vinyl acetic acid, 4-pentenoic acid and fumaric acid; the molecular weight regulator is water soluble chain transfer agent, including at least one of phosphorous acid, hypophosphorous acid, sodium hypophosphite, potassium hypophosphite, mercaptoethanol, thioglycerol, thioglycollic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, thiomalic acid, octyl mercaptoacetate, octyl 3-mercaptopropionate and 2-mercaptoethane sulfonic acid, and the dosage of the molecular weight regulator is 0.3-0.8% of the mass of the unsaturated polyether macromonomer.
Further, the initiator comprises at least one of a hydrogen peroxide-sodium formaldehyde sulfoxylate-ferrous sulfate heptahydrate composition, a hydrogen peroxide-ascorbic acid-ferrous pyrophosphate composition, a hydrogen peroxide-2-hydroxy-2-sulfinylacetic acid-disodium salt-stannous sulfate composition, an ammonium persulfate-sodium formaldehyde sulfoxylate-titanyl sulfate composition, a tert-butyl hydrogen peroxide-ascorbic acid-ferrous sulfate heptahydrate composition, a tert-butyl hydrogen peroxide-2-hydroxy-2-sulfinylacetic acid-disodium salt-ferrous pyrophosphate composition, and the initiator is used in an amount of 0.5-1.5% of the mass of the unsaturated polyether macromonomer.
The preparation method of the high-dispersion plastic-retaining polycarboxylate superplasticizer special for phosphogypsum comprises the following steps of:
(1) Dissolving an unsaturated polyether macromonomer, tetrahydrophthalic anhydride acylated amino-terminated polyether monomer and an initiator in deionized water to obtain a base material;
(2) Dissolving the rest initiator and the molecular weight regulator in deionized water to prepare a mixed solution A material;
(3) Dissolving unsaturated carboxylic acid and unsaturated phosphoric monoester functional monomer in deionized water to prepare a mixed solution B material;
(4) And (3) dropwise adding the mixed solution A material and the mixed solution B material into the base material at the initial temperature of 10-25 ℃, preserving heat until the reaction is finished after the dropwise adding, adjusting the pH value, and supplementing water until the solid content is 49-51%, thus obtaining the modified polyurethane foam.
The beneficial effects of the invention are as follows:
(1) According to the polycarboxylic acid water reducer provided by the invention, the unsaturated polyether macromonomer is chain-extended by adopting the compound with carboxyl, phosphate group, phenyl, amido, amino and polyoxyethylene group on the molecular structure, and more rigid groups, polar groups and heterogeneous charges are endowed to the branched chain of the water reducer, so that the steric hindrance, the acting force between chains and the terminal electrostatic acting force of the branched chain of the polycarboxylic acid water reducer are enhanced, the synergistic effect among all the components is fully exerted, the water reducer can be enhanced in the multilayer adsorption, the inter-particle steric hindrance repulsion and the electrostatic repulsion effects of the gypsum-based self-leveling mortar material, the water reducing rate is improved, and the plasticity is better.
(2) By introducing amino groups, amides and other groups with early strength into the molecules of the polycarboxylic acid water reducer, needle-like crystals in the crystal structure of the gypsum hardened body are reduced after the polycarboxylic acid water reducer is added, a large number of column plate-shaped compact crystals with complete structures and amorphous gelatinous substances are generated, the length-diameter ratio of the crystals is reduced, the number of nodes among the crystals is increased, the contact points develop well, mutual lap joint is tighter, a complete crystallization network system is formed, and therefore the mechanical property of the gypsum hardened body is improved, and the fracture-resistant compressive strength of the gypsum hardened body is improved.
(3) Because the hydration speed of the gypsum is too high, the dispersibility of the gypsum is poor, the loss of fluidity with time is large, and the compressive strength and the flexural strength are low and cannot meet the standard requirements. Unsaturated phosphate is introduced into the molecular structure of the polycarboxylate water reducer, and contains amide groups, hydroxyl groups and phosphate groups, so that the polycarboxylate water reducer can be gradually hydrolyzed in a strong alkaline environment, and hydrophilic groups such as carboxyl groups and the like can be continuously released, so that good dispersibility is shown; in alkaline environment, phosphate groups are released after hydrolysis, and the phosphate groups have more negative charges than carboxyl groups, so that the adsorption capacity of the synthesized polycarboxylate superplasticizer is higher than that of a common polycarboxylate superplasticizer, and the synthesized polycarboxylate superplasticizer has better plastic retention performance.
(4) The industrial production is more than using P 2 O 5 The phosphating reagent is used for phosphating reaction to obtain a mixture of monoester and diester, but the reaction is easy to cause local reaction to be severe, the reaction is uneven, the operation is not easy to control, if the generated heat is not timely and fully diffused, the reactant can be dehydrated to deepen the color of the product, the quality and the yield of the product are finally influenced, and the monoester with high content is not obtained. And use P 2 O 5 Compared with the phosphating reaction, the polyphosphoric acid is in a liquid state and can be mutually dissolved with the hydroxyl compound under the condition of no solvent, the reaction conversion rate is higher, the most effective method for obtaining the phosphoric monoester with higher purity is realized, and the P is also used in operation 2 O 5 The method has the advantages of convenience, mild reaction conditions, easiness in operation, no exhaust gas and waste liquid emission and wide industrial application prospect.
(5) In the polymerization reaction, an oxidation-reduction initiation system is adopted, so that the initiation temperature of the reaction can be reduced, the controllability is high, the initiation efficiency is high, the reaction time is shortened by 1.5-2.5 hours compared with the conventional water reducer process, meanwhile, the reaction condition is mild, the production equipment and process are simple, the economic cost is reduced, the energy is saved, and the large-scale production is easy to realize.
Detailed Description
Example 1
The special high-dispersion plastic-retaining polycarboxylate water reducer for phosphogypsum has a finished product mother liquor pH value of 12.3 and a solid content of 49.5 percent, and the preparation method comprises the following steps:
(1) Preparation of tetrahydrophthalic anhydride acylated amino-terminated polyether monomer: adding 48.6g of tetrahydrophthalic anhydride and 70g of polyoxypropylene diamine (with the molecular weight of 230) into a round bottom four-neck flask with a stirrer, a thermometer and a condenser, dissolving in 29.7g of N, N-dimethylformamide, uniformly stirring, heating to 95 ℃, adding 2.6g of 4-dimethylaminopyridine, carrying out heat preservation reaction for 5.5 hours, and carrying out reduced pressure distillation to remove an organic solvent after the acylation reaction is finished to obtain an acylated amino polyether monomer TP-1 of the tetrahydrophthalic anhydride;
(2) Unsaturated phosphoric monoester functional monomer preparation: 52.6-g N-hydroxyethyl acrylamide and 154.4g of tetraphosphoric acid with the content of 115 percent (calculated by mass fraction of phosphoric acid) are added into a round-bottom four-neck flask with a stirrer and a thermometer, the feeding temperature is controlled to be not more than 30 ℃, the device is put into a water bath kettle for stirring after the feeding is finished, the temperature is raised to 65 ℃, after the phosphating reaction is carried out for 4.5 hours, 23g of deionized water is weighed and added into the four-neck flask for hydrolysis reaction, the temperature is raised to 75 ℃ for 2 hours, and the unsaturated phosphoric acid monoester functional monomer POP-1 is obtained after cooling;
(3) And (3) preparing a polycarboxylate water reducer: 360g of ethylene glycol monovinyl polyoxyethylene ether (with a molecular weight of 3000), 6.4g of tetrahydrophthalic anhydride acylated amino-terminated polyether monomer TP-1, 3.6g of hydrogen peroxide and 0.01g of ferrous pyrophosphate are added into 310g of deionized water, stirred until the mixture is completely dissolved, then a mixed solution A material consisting of 0.6g of ascorbic acid, 1.6g of thioglycollic acid and 70g of deionized water and a mixed solution B material consisting of 33.2g of acrylic acid, 5.6g of unsaturated phosphoric monoester functional monomer POP-1 and 20g of deionized water are sequentially added dropwise, the initial dropwise adding temperature is 15 ℃, the dropwise adding time of the mixed solution A is controlled to be 1.5h, the dropwise adding time of the mixed solution B is controlled to be 1.0h, and after dropwise adding, the mixed solution B material is continuously kept for 0.5h; after the reaction is finished, 48g of 30% sodium hydroxide is added to adjust the pH value of the reaction product to 12.3, then water is added, and the solid content is adjusted to 49.5%, so that the special high-dispersion plastic-retaining polycarboxylate superplasticizer TZ-PG1 for phosphogypsum is obtained.
Example 2
The special high-dispersion plastic-retaining polycarboxylate water reducer for phosphogypsum has a finished product mother liquor pH value of 12.6 and a solid content of 50.3 percent, and the preparation method comprises the following steps:
(1) Preparation of tetrahydrophthalic anhydride acylated amino-terminated polyether monomer: adding 33.6g of tetrahydrophthalic anhydride and 86.3g of polyoxypropylene diamine (with molecular weight of 430) into a round bottom four-neck flask with a stirrer, a thermometer and a condenser, dissolving in 30g of toluene, stirring uniformly, heating to 105 ℃, adding 3.6g of p-toluenesulfonic acid, reacting for 4.5h under heat preservation, and distilling under reduced pressure to remove the organic solvent after the acylation reaction is finished to obtain an acylated amino polyether monomer TP-2 of the tetrahydrophthalic anhydride;
(2) Unsaturated phosphoric monoester functional monomer preparation: 48.5g N- (3-hydroxypropyl) acrylamide and 126.9g of tetraphosphoric acid with the content of 115 percent (calculated by mass fraction of phosphoric acid) are added into a round-bottom four-neck flask with a stirrer and a thermometer, the feeding temperature is controlled to be not more than 30 ℃, the device is put into a water bath kettle to be started for stirring after the feeding is completed, the temperature is raised to 70 ℃, 25g of deionized water is weighed after the phosphating reaction is carried out for 4 hours, the hydrolysis reaction is carried out in the four-neck flask, the temperature is raised to 80 ℃, the reaction is finished for 2 hours, and the unsaturated phosphoric acid monoester functional monomer POP-2 is obtained after cooling;
(3) And (3) preparing a polycarboxylate water reducer: 350g of methylallyl alcohol polyoxyethylene ether (with a molecular weight of 3000), 8.6g of tetrahydrophthalic anhydride acylated amino-terminated polyether monomer TP-2, 4.0g of hydrogen peroxide and 0.012g of ferrous sulfate heptahydrate are added into 300g of deionized water, stirred until the mixture is completely dissolved, then mixed solution A consisting of 0.6g of sodium formaldehyde sulfoxylate, 3.2g of hypophosphorous acid and 65g of deionized water and mixed solution B consisting of 28.8g of acrylic acid, 6g of 3, 3-dimethyl acrylic acid and 4.8g of unsaturated phosphoric monoester functional monomer POP-2 and 30g of deionized water are sequentially added dropwise, the initial dropwise adding temperature is 19 ℃, the dropwise adding time of the mixed solution A is controlled to be 2.5h, the dropwise adding time of the mixed solution B is controlled to be 2.0h, and after dropwise adding is completed, the mixed solution A is kept warm for 1.0h; after the reaction is finished, 52g of 30% sodium hydroxide is added to adjust the pH value of the reaction product to 12.6, then water is added, and the solid content is adjusted to 50.3%, so that the special high-dispersion plastic-retaining polycarboxylate superplasticizer TZ-PG2 for phosphogypsum is obtained.
Example 3
The special high-dispersion plastic-retaining polycarboxylate water reducer for phosphogypsum has a finished product mother liquor pH value of 11.8 and a solid content of 49.7 percent, and the preparation method comprises the following steps:
(1) Preparation of tetrahydrophthalic anhydride acylated amino-terminated polyether monomer: adding 54.6g of tetrahydrophthalic anhydride and 56g of triethylene glycol diamine (molecular weight is 148.23) into a round bottom four-neck flask with a stirrer, a thermometer and a condenser, dissolving in 19.6g of toluene and 8g of N, N-dimethylacetamide, uniformly stirring, heating to 85 ℃, adding 3.1g of methanesulfonic acid, carrying out heat preservation reaction for 6 hours, and carrying out reduced pressure distillation to remove an organic solvent after the acylation reaction is finished to obtain an amino polyether monomer TP-3 of the acylated end of the tetrahydrophthalic anhydride;
(2) Unsaturated phosphoric monoester functional monomer preparation: adding 56g N- (2-hydroxypropyl) methacrylamide and 132.2g of tetraphosphoric acid with the content of 115 percent (calculated by mass fraction of phosphoric acid) into a round-bottom four-neck flask with a stirrer and a thermometer, controlling the feeding temperature to be not more than 30 ℃, putting the device into a water bath kettle to start stirring after the feeding is completed, heating to 65 ℃, after phosphating for 5.5 hours, weighing 21.8g of deionized water, adding into the four-neck flask to carry out hydrolysis reaction, heating to 70 ℃, finishing the reaction for 2 hours, and cooling to obtain an unsaturated phosphoric monoester functional monomer POP-3;
(3) And (3) preparing a polycarboxylate water reducer: 340g of ethylene glycol monovinyl polyoxyethylene ether (molecular weight: 5000), 7.6g of tetrahydrophthalic anhydride acylated amino-terminated polyether monomer TP-3 and 2.4g of hydrogen peroxide, 0.006gStannous sulfateAdding the mixture into 290g of deionized water, stirring until the mixture is completely dissolved, then sequentially dropwise adding a mixed solution A material consisting of 0.52g of 2-hydroxy-2-sulfinylacetic acid-disodium salt, 1.8g of mercaptopropionic acid and 60g of deionized water and a mixed solution B material consisting of 27.5g of methacrylic acid, 6.2g of unsaturated phosphoric monoester functional monomer POP-3 and 20g of deionized water, wherein the initial dropwise adding temperature is 16 ℃, the dropwise adding time of the mixed solution A is controlled to be 1.0h, the dropwise adding time of the mixed solution B is controlled to be 0.8h, and continuously preserving the heat for 1.0h after the dropwise adding is completed; after the reaction is finished, 45g of 30% sodium hydroxide is added to adjust the pH value of the reaction product to 11.8, then water is added, and the solid content is adjusted to 49.7%, so that the special high-dispersion plastic-retaining polycarboxylate superplasticizer TZ-PG3 for phosphogypsum is obtained.
Example 4
The special high-dispersion plastic-retaining polycarboxylate water reducer for phosphogypsum has a finished product mother liquor pH value of 12.6 and a solid content of 50.5 percent, and the preparation method comprises the following steps:
(1) Preparation of tetrahydrophthalic anhydride acylated amino-terminated polyether monomer: adding 21.2g of tetrahydrophthalic anhydride and 88.7g of polyoxyethylene-polyoxypropylene copolyether diamine (with the molecular weight of 700) into a round bottom four-neck flask with a stirrer, a thermometer and a condenser, dissolving in 36.6g of ethyl acetate, uniformly stirring, heating to 110 ℃, adding 2.3g of 4-dimethylaminopyridine, carrying out heat preservation reaction for 5 hours, and carrying out reduced pressure distillation to remove an organic solvent after the acylation reaction is finished to obtain an amino polyether monomer TP-4 of the acylated end of the tetrahydrophthalic anhydride;
(2) Unsaturated phosphoric monoester functional monomer preparation: 48g N- (4-hydroxybutyl) acrylamide and 124.6g of tetraphosphoric acid with the content of 115 percent (calculated by mass fraction of phosphoric acid) are added into a round-bottom four-neck flask with a stirrer and a thermometer, the feeding temperature is controlled to be not more than 30 ℃, the device is put into a water bath kettle for stirring after the feeding is finished, the temperature is raised to 70 ℃, 27.4g of deionized water is weighed after the phosphating reaction is carried out for 5 hours, the hydrolysis reaction is carried out in the four-neck flask, the temperature is raised to 75 ℃, the reaction is finished for 2 hours, and the unsaturated phosphoric acid monoester functional monomer POP-4 is obtained after cooling;
(3) And (3) preparing a polycarboxylate water reducer: 365g of methylallyl alcohol polyoxyethylene ether (with a molecular weight of 4000), 6.6g of tetrahydrophthalic anhydride acylated amino-terminated polyether monomer TP-4, 2.8g of ammonium persulfate and 0.01g of titanyl sulfate are added into 300g of deionized water, stirred until the mixture is completely dissolved, then mixed solution A consisting of 1.2g of sodium formaldehyde sulfoxylate, 1.6g of thioglycollic acid and 80g of deionized water and mixed solution B consisting of 24.2g of acrylic acid, 8g of vinyl acetic acid, 5.6g of unsaturated phosphoric monoester functional monomer POP-4 and 30g of deionized water are sequentially added dropwise, the initial dropwise adding temperature is 25 ℃, the dropwise adding time of the mixed solution A is controlled to be 2.5h, the dropwise adding time of the mixed solution B is controlled to be 2.5h, and the mixed solution A is kept warm for 0.5h after dropwise adding; after the reaction is finished, 49g of 30% sodium hydroxide is added to adjust the pH value of the reaction product to 12.6, then water is added, and the solid content is adjusted to 50.5%, so that the special high-dispersion plastic-retaining polycarboxylate superplasticizer TZ-PG4 for phosphogypsum is obtained.
Example 5
The special high-dispersion plastic-retaining polycarboxylate water reducer for phosphogypsum has a finished product mother liquor pH value of 11.6 and a solid content of 49.3, and the preparation method comprises the following steps:
(1) Preparation of tetrahydrophthalic anhydride acylated amino-terminated polyether monomer: 15.6g of tetrahydrophthalic anhydride and 93.2g of polytetramethylene ether diamine (molecular weight 1000) were placed in a round-bottomed four-necked flask equipped with a stirrer, thermometer and condenser. Dissolving in 20g toluene and 16g N, N-dimethylacetamide, stirring uniformly, heating to 120 ℃, adding 1.2g benzenesulfonic acid and 2.2g p-toluenesulfonic acid, reacting for 4.5 hours at a constant temperature, and distilling under reduced pressure to remove the organic solvent after the acylation reaction is finished to obtain tetrahydrophthalic anhydride acylated amino polyether monomer TP-5;
(2) Unsaturated phosphoric monoester functional monomer preparation: adding 53.4g N- (2-hydroxyethyl) methacrylamide and 146.7g of tetraphosphoric acid with the content of 115 percent (calculated by mass fraction of phosphoric acid) into a round-bottom four-neck flask with a stirrer and a thermometer, controlling the feeding temperature to be not more than 30 ℃, putting the device into a water bath kettle to start stirring after the feeding is finished, heating to 60 ℃, after phosphating for 5 hours, weighing 25g of deionized water, adding into the four-neck flask to carry out hydrolysis reaction, heating to 80 ℃, finishing the reaction for 2 hours, and cooling to obtain an unsaturated phosphoric monoester functional monomer POP-5;
(3) And (3) preparing a polycarboxylate water reducer: 200g of ethylene glycol monovinyl polyoxyethylene ether (with a molecular weight of 3000), 160g of methyl allyl alcohol polyoxyethylene ether (with a molecular weight of 3000), 7.2g of tetrahydrophthalic anhydride acylated amino-terminated polyether monomer TP-5, 3.6g of tertiary butyl hydroperoxide and 0.012g of ferrous pyrophosphate are added into 310g of deionized water, stirred until the mixture is completely dissolved, then a mixed solution A consisting of 0.6g of 2-hydroxy-2-sulfinylacetic acid, 3.2g of sodium hypophosphite and 80g of deionized water and a mixed solution B consisting of 24.2g of acrylic acid, 10g of fumaric acid, 6.4g of unsaturated phosphoric monoester functional monomer POP-5 and 30g of deionized water are sequentially added dropwise, the initial dropwise adding temperature is 16 ℃, the dropwise adding time of the mixed solution A is controlled to be 1.5h, the dropwise adding time of the mixed solution B is controlled to be 1.0h, and the heat preservation is continued for 0.5h after the dropwise adding is completed; after the reaction is finished, 42g of 30% sodium hydroxide is added to adjust the pH value of the reaction product to 11.6, then water is added, and the solid content is adjusted to 49.3%, so that the special high-dispersion plastic-retaining polycarboxylate superplasticizer TZ-PG5 for phosphogypsum is obtained.
Example 6
The special high-dispersion plastic-retaining polycarboxylate water reducer for phosphogypsum has a finished product mother liquor pH value of 11.4 and a solid content of 49.6 percent, and the preparation method comprises the following steps:
(1) Preparation of tetrahydrophthalic anhydride acylated amino-terminated polyether monomer: adding 35.6g of tetrahydrophthalic anhydride and 87.6g of polyoxyethylene diamine (with molecular weight of 412) into a round bottom four-neck flask with a stirrer, a thermometer and a condenser, dissolving in 30.8g of acetone, stirring uniformly, heating to 85 ℃, adding 5.2g of anhydrous aluminum trichloride, carrying out heat preservation reaction for 6 hours, and carrying out reduced pressure distillation to remove an organic solvent after the acylation reaction is finished to obtain an acylated amino polyether monomer TP-6 of the tetrahydrophthalic anhydride;
(2) Unsaturated phosphoric monoester functional monomer preparation: adding 42g N-methylol acrylamide and 147.4g of tetraphosphoric acid with the content of 115 percent (calculated by mass fraction of phosphoric acid) into a round-bottom four-neck flask with a stirrer and a thermometer, controlling the feeding temperature to be not more than 30 ℃, putting the device into a water bath kettle after the feeding is finished, starting stirring, heating to 65 ℃, carrying out phosphating reaction for 4.5 hours, weighing 20.6g of deionized water, adding into the four-neck flask, carrying out hydrolysis reaction, heating to 70 ℃, finishing the reaction for 2 hours, and cooling to obtain an unsaturated phosphoric acid monoester functional monomer POP-6;
(3) And (3) preparing a polycarboxylate water reducer: 200g of methylallyl alcohol polyoxyethylene ether (with a molecular weight of 3000), 160g of ethylene glycol monovinyl polyoxyethylene ether (with a molecular weight of 5000), 7.6g of tetrahydrophthalic anhydride acylated amino-terminated polyether monomer TP-6, 3.6g of tertiary butyl hydroperoxide and 0.01g of ferrous sulfate heptahydrate are added into 310g of deionized water, stirred until the mixture is completely dissolved, then a mixed solution A material consisting of 0.6g of ascorbic acid, 1.6g of hypophosphorous acid, 1.8g of sodium hypophosphite and 70g of deionized water and a mixed solution B material consisting of 27.2g of methacrylic acid, 7.6g of 4-pentenoic acid, 6.6g of unsaturated phosphoric monoester functional monomer POP-6 and 30g of deionized water are sequentially added dropwise, the initial dropwise adding temperature is 23 ℃, the dropwise adding time of the mixed solution A material is controlled to be 1.5h, and after dropwise adding is completed, the mixed solution B material is continuously kept for 1h; after the reaction is finished, 42g of 30% sodium hydroxide is added to adjust the pH value of the reaction product to 11.4, then water is added, and the solid content is adjusted to 49.6%, so that the special high-dispersion plastic-retaining polycarboxylate superplasticizer TZ-PG6 for phosphogypsum is obtained.
Test examples
The following performance test experiments are carried out on the special high-dispersion plastic-retaining polycarboxylate superplasticizer for phosphogypsum, which is prepared by the invention:
(1) materials for testing: phosphogypsum hemihydrate, sichuan shi 370225; cement, conch brand p.o42.5 common Portland cement, sichuan Guangyuan; superfine gray calcium powder, sichuan Mianyang; gypsum retarder, defoamer, stabilizer, hebei Shijia; water, tap water; additive, commercial powder polycarboxylate superplasticizer PCE-SG1 and commercial polycarboxylate superplasticizer mother liquor PCE-SG2 (solid content is 50%).
(2) The polycarboxylic acid water reducer TZ-PG1 to TZ-PG6 obtained in the above examples 1 to 6, and the commercial polycarboxylic acid water reducer PCE-SG1 and PCE-SG2 were added in the same refraction and fixation mixing amounts, and stirred at a low speed by a stirrer for 1min and then rapidly stirred for 2min to obtain the gypsum-based self-leveling mortar. The mixing ratio of the gypsum-based self-leveling mortar is shown in table 1. (3) The physical property evaluation of the gypsum-based self-leveling mortar test is carried out by referring to JC/T1023-2021 Standard of gypsum-based self-leveling mortar, and the initial fluidity, 30min flow expansion degree, 24h compression and bending strength and 28d absolute compression and bending strength are detected, and the comparison results are shown in the following table 2.
TABLE 1 mixing ratio/G of Gypsum-based self-leveling mortar (G20)
Table 2 influence of water reducing agent on phosphogypsum self-leveling mortar performance
As can be seen from the comparison of Table 2, the same amount of water reducer is added into phosphogypsum-based self-leveling mortar, and the comparison result shows that when two commercial water reducers are used, the phosphogypsum-based self-leveling mortar has smaller initial fluidity, excessive 30min fluidity loss and low absolute dry fracture and compression strength of 24h and 28d, and can not meet the standard requirement. When the polycarboxylic acid water reducers TZ-PG 1-TZ-PG 6 obtained in the examples 1-6 are used, the phosphogypsum-based self-leveling mortar has larger initial fluidity, the fluidity is larger than the initial fluidity for 30min, no fluidity loss exists, and the absolute dry fracture compression strength of 24h and 28d also meets the standard requirement. Compared with the commercial polycarboxylate superplasticizer, the polycarboxylate superplasticizer special for phosphogypsum has higher dispersibility and plasticity-maintaining performance, high flexural compression strength and obvious advantages.
The foregoing is only a preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art, who is within the scope of the present invention, should make equivalent substitutions or modifications according to the technical scheme of the present invention and the inventive concept thereof, and should be covered by the scope of the present invention.
Claims (7)
1. The special high-dispersion plastic-retaining polycarboxylate water reducer for phosphogypsum is characterized by comprising an unsaturated polyether macromonomer, an unsaturated carboxylic acid, a tetrahydrophthalic anhydride acylated amino-terminated polyether monomer, an unsaturated phosphoric monoester functional monomer, an initiator, a molecular weight regulator and water, wherein the mass ratio of the unsaturated polyether macromonomer to the unsaturated carboxylic acid to the tetrahydrophthalic anhydride acylated amino-terminated polyether monomer to the unsaturated phosphoric monoester functional monomer to the initiator to the molecular weight regulator is 340-370:20-35:5-10:3-8:2.5-5:1.0-3.5, the solid content of the finished product mother solution of the polycarboxylate water reducer is 49-51%, and the pH value is 10.0-13.0;
the tetrahydrophthalic anhydride acylated amino-terminated polyether monomer is prepared by the following method: dissolving tetrahydrophthalic anhydride and amine-terminated polyether in an organic solvent, heating to 70-120 ℃ under stirring, adding a catalyst into the mixture, carrying out an acylation reaction for 5-8h under heat preservation, and removing the organic solvent after the reaction is finished to obtain the modified polyamide;
wherein the molar ratio of the tetrahydrophthalic anhydride to the amino-terminated polyether is 1.0-1.1:1; the catalyst is one or two of anhydrous aluminum trichloride, trifluoroacetic acid, 4-dimethylaminopyridine, benzenesulfonic acid, methanesulfonic acid, sulfamic acid and p-toluenesulfonic acid, and the dosage of the catalyst is 2.0-5.0% of the total mass of tetrahydrophthalic anhydride and amino-terminated polyether; the organic solvent is at least one of ethyl acetate, N-dimethylformamide, N-dimethylacetamide, toluene and acetone, and the dosage of the organic solvent accounts for 5-25% of the total mass of the materials; the amino-terminated polyether is polyether diamine compound terminated by amino or amino, and the molecular weight of the amino-terminated polyether is 100-1000.
2. The phosphogypsum-specific high-dispersion plastic-retaining polycarboxylate water reducer as set forth in claim 1, wherein the amine-terminated polyether comprises at least one of triethylene glycol diamine, tripropylene glycol diamine, polyoxyethylene diamine, polyoxypropylene diamine, polyoxyethylene-polyoxypropylene copolyether diamine and polytetramethylene ether diamine.
3. The special high-dispersion plastic-retaining polycarboxylate water reducer for phosphogypsum, as set forth in claim 1, wherein the unsaturated phosphate monoester functional monomer is prepared by the following method: mixing N-hydroxyalkyl acrylamide and polyphosphoric acid, heating to 50-70 ℃ for phosphating reaction for 4-6h, adding water into the mixture, heating to 60-80 ℃ for hydrolysis reaction for 1.5-3h, and obtaining the N-hydroxyalkyl acrylamide.
4. The phosphogypsum-specific high-dispersion plastic-retaining polycarboxylate superplasticizer as set forth in claim 3, wherein the molar ratio of the N-hydroxyalkyl acrylamide to the polyphosphoric acid is 1:1.0-1.1; the N-hydroxyalkyl acrylamide comprises one of N-methylolacrylamide, N-hydroxyethyl acrylamide, N- (3-hydroxypropyl) acrylamide, N- (4-hydroxybutyl) acrylamide, N-methylolmethacrylamide, N- (2-hydroxyethyl) methacrylamide and N- (2-hydroxypropyl) methacrylamide; the polyphosphoric acid comprises at least one of tripolyphosphoric acid, tetraphosphoric acid, pentaphosphoric acid and hexaphosphoric acid.
5. The special high-dispersion plastic-retaining polycarboxylate superplasticizer for phosphogypsum, as set forth in claim 1, wherein the unsaturated polyether macromonomer is ethylene glycol monovinyl polyoxyethylene ether and/or methallyl alcohol polyoxyethylene ether, and the molecular weight of the unsaturated polyether macromonomer is 3000-5000; the unsaturated carboxylic acid is at least one of acrylic acid, methacrylic acid, 3-dimethyl acrylic acid, vinyl acetic acid, 4-pentenoic acid and fumaric acid; the molecular weight regulator is a water-soluble chain transfer agent and comprises at least one of phosphorous acid, hypophosphorous acid, sodium hypophosphite, potassium hypophosphite, mercaptoethanol, thioglycerol, thioglycolic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, thiomalic acid, octyl mercaptoacetate, octyl 3-mercaptopropionate and 2-mercaptoethane sulfonic acid, and the dosage of the molecular weight regulator is 0.3-0.8% of the mass of the unsaturated polyether macromonomer.
6. The high-dispersion plastic-retaining polycarboxylate water reducer special for phosphogypsum as set forth in claim 1, wherein the initiator comprises hydrogen peroxide-sodium formaldehyde sulfoxylate-ferrous sulfate heptahydrate composition, hydrogen peroxide-ascorbic acid-ferrous pyrophosphate composition, hydrogen peroxide-2-hydroxy-2-sulfinylacetic acid-disodium salt-Stannous sulfateAt least one of a composition, an ammonium persulfate-sodium formaldehyde sulfoxylate-titanyl sulfate composition, a tert-butyl hydroperoxide-ascorbic acid-ferrous sulfate heptahydrate composition and a tert-butyl hydroperoxide-2-hydroxy-2-sulfinylacetic acid-disodium salt-ferrous pyrophosphate composition, wherein the use amount of the initiator is 0.5-1.5% of the mass of the unsaturated polyether macromonomer.
7. The method for preparing the high-dispersion plastic-retaining polycarboxylate superplasticizer special for phosphogypsum as set forth in any one of claims 1-6, which is characterized by comprising the following steps:
(1) Dissolving an unsaturated polyether macromonomer, tetrahydrophthalic anhydride acylated amino-terminated polyether monomer and an initiator in deionized water to obtain a base material;
(2) Dissolving an initiator and a molecular weight regulator in deionized water to prepare a mixed solution A material;
(3) Dissolving unsaturated carboxylic acid and unsaturated phosphoric monoester functional monomer in deionized water to prepare a mixed solution B material;
and (3) dropwise adding the mixed solution A material and the mixed solution B material into the base material at the initial temperature of 10-25 ℃, preserving heat until the reaction is finished after the dropwise adding, adjusting the pH value, and supplementing water until the solid content is 49-51%, thus obtaining the modified polyurethane foam.
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