High-strength geopolymer hollow microsphere, preparation method thereof and phase change energy storage microsphere

Abstract

A high-strength geopolymer hollow microsphere, a preparation method thereof and a phase change energy storage microsphere are provided, including: dissolving sodium hydroxide, sodium silicate and spheroidizing aid in water to form a solution A, and adding active powder to the solution A, stirring and uniformly mixing to form a slurry B, adding the slurry B to an oil phase, stirring and dispersing into balls, filtering to obtain geopolymer microspheres I, washing the geopolymer microspheres I, and then carrying out a high-temperature calcination to obtain the high-strength geopolymer hollow microspheres II; using the high-strength geopolymer hollow microsphere as a carrier, absorbing a phase change material into the carrier, and mixing a microsphere carrying the phase change material with an epoxy resin, adding a powder dispersant and stirring to disperse the microsphere, after the epoxy resin is solidified, screening the superfluous powder dispersant to obtain the phase energy storage microsphere.

Claims

1. A method of preparing high-strength geopolymer hollow microspheres, comprising: dissolving sodium hydroxide (NaOH), sodium silicate (Na.sub.2SiO.sub.3.9H.sub.2O) and a spheroidizing aid in water to form a solution, adding active powder to the solution to obtain a first mixture, stirring and uniformly mixing the first mixture to form a slurry, adding the slurry to an oil phase dispersion medium to obtain a second mixture, stirring the second mixture to disperse the slurry into the oil phase dispersion medium to form balls, after the stirring, filtering the second mixture to obtain geopolymer microspheres, washing the geopolymer microspheres, and then carrying out a high-temperature calcination on the geopolymer microspheres to obtain the high-strength geopolymer hollow microspheres; wherein a mass percentage of the sodium hydroxide (NaOH), the sodium silicate (Na.sub.2SiO.sub.3.9H.sub.2O) and the spheroidizing aid is (10-40%): (20-60%): (20-60%), a mass ratio of the water to the active powder is 1:2-1, the slurry accounts for 5%-50% of a volume of the oil phase dispersion medium, a temperature of the high-temperature calcination is 800-1500° C., and a time of the high-temperature calcination is 1-8 hours.

2. The method of preparing the high-strength geopolymer hollow microspheres of claim 1, wherein the mass percentage of the sodium hydroxide (NaOH), the sodium silicate (Na.sub.2SiO.sub.3.9H.sub.2O) and the spheroidizing aid is (12-20%): (40-60%): (30-50%), the mass ratio of the water to the active powder is 1:1.5-1, and the slurry B accounts for 10%-40% of the volume of the oil phase dispersion medium.

3. The method of preparing the high-strength geopolymer hollow microspheres of claim 1, wherein the temperature of the high-temperature calcination is 850-1200° C., and the time of the high-temperature calcination is 1-2 hours.

4. The method of preparing the high-strength geopolymer hollow microspheres of claim 1, wherein the spheroidizing aid is a sodium salt and a potassium salt.

5. The method of preparing the high-strength geopolymer hollow microspheres of claim 4, wherein the sodium salt comprises one or more selected from the group consisting of sodium carbonate, sodium chloride, sodium nitrate, and sodium sulfate; and the potassium salt comprises one or more selected from the group consisting of potassium chloride, potassium carbonate, and potassium sulfate.

6. The method of preparing the high-strength geopolymer hollow microspheres of claim 1, wherein the active powder comprises one or more selected from the group consisting of fly ash, metakaolin and slag, and the active powder has a mesh number of 500-1000 mesh.

7. The method of preparing the high-strength geopolymer hollow microspheres of claim 1, wherein the oil phase dispersion medium is a corn oil, a soybean oil, a peanut oil, a kerosene, a castor oil, or a rapeseed oil.

8. The method of preparing the high-strength geopolymer hollow microspheres of claim 1, wherein a temperature of the oil phase dispersion medium is 50-90° C.

9. The method of preparing the high-strength geopolymer hollow microspheres of claim 1, wherein a stirring speed of dispersing the slurry into the oil phase dispersion medium is 400-1000 r/min, and a stirring time is 0.5-3 hours.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The above and/or additional aspects and advantages of the present invention will become apparent and readily understood in the description of the embodiments in conjunction with the following drawings.

(2) FIG. 1 is a micrograph showing a geopolymer hollow microsphere, with a particle size of 50-100 μm;

(3) FIG. 2 is a broken microsphere showing that the microsphere is hollow (the microsphere and a cavity inside the microsphere can be clearly seen from the figure);

(4) FIG. 3 is a micrograph showing a phase change energy storage microsphere dispersed by calcium carbonate powder; and

(5) FIG. 4 is a micrograph showing paraffin absorbed into geopolymer hollow microspheres.

DETAILED DESCRIPTION OF THE EMBODIMENTS

(6) The present invention will be further described in conjunction with the drawings and embodiments. It should be noted that the following description is only for the purpose of explaining the present invention and is not intended to limit the content thereof.

Embodiment 1

(7) High-Strength Geopolymer Hollow Microspheres, and a Preparation Method thereof

(8) 1.5 g of sodium hydroxide (NaOH), 5 g of sodium silicate (Na.sub.2SiO.sub.3.9H.sub.2O) and 3 g of sodium chloride (NaCl) were dissolved in 10 g of water to form a solution A, and 10 g of metakaolin was added to the solution A, stirred and uniformly mixed to form a slurry B, the slurry B was added to a corn oil, wherein the slurry B accounts for 10% of a volume of the corn oil. The slurry B was stirred to disperse into balls, a stirring speed was 600 r/min, a stirring time was 0.5 hours, and a temperature of the corn oil is 55° C. A filtration was performed to obtain geopolymer microspheres I. The geopolymer microspheres I were washed, and then subjected to a high-temperature calcination at 850° C. for 2 hours to obtain the high-strength geopolymer hollow microspheres (M1). The microspheres have a particle size of 50-100 μm, a compressive strength of 23 MPa, a wall thickness of 10 μm, and a density of 0.60 g/cm.sup.3.

Embodiment 2

(9) High-Strength Geopolymer Hollow Microspheres, and a Preparation Method thereof.

(10) 2 g of sodium hydroxide (NaOH), 6 g of sodium silicate (Na.sub.2SiO.sub.3.9H.sub.2O) and 4.5 g of sodium chloride (NaCl) were dissolved in 10 g of water to form a solution A, and 15 g of metakaolin was added to the solution A, stirred and uniformly mixed to form a slurry B, the slurry B was added to a soybean oil, wherein the slurry B accounts for 15% of a volume of the soybean oil. The slurry B was stirred to disperse into balls, a stirring speed was 400 r/min, a stirring time was 1.5 hours, and a temperature of the soybean oil is 65° C. A filtration was performed to obtain geopolymer microspheres I. The geopolymer microspheres I were washed, and then subjected to a high-temperature calcination at 1000° C. for 1.5 hours to obtain the high-strength geopolymer hollow microspheres (M2). The microspheres have a particle size of 250-300 μm, a compressive strength of 27 MPa, a wall thickness of 45 μm, and a density of 0.65 g/cm.sup.3.

Embodiment 3

(11) High-Strength Geopolymer Hollow Microspheres, and a Preparation Method thereof.

(12) 1.2 g of sodium hydroxide (NaOH), 4 g of sodium silicate (Na.sub.2SiO.sub.3.9H.sub.2O) and 5 g of sodium chloride (NaCl) were dissolved in 10 g of water to form a solution A, and 12 g of metakaolin was added to the solution A, stirred and uniformly mixed to form a slurry B, the slurry B was added to a corn oil, wherein the slurry B accounts for 40% of a volume of the corn oil. The slurry B was stirred to disperse into balls, a stirring speed was 500 r/min, a stirring time was 2.0 hours, and a temperature of the corn oil is 75° C. A filtration was performed to obtain geopolymer microspheres I. The geopolymer microspheres I were washed, and then subjected to a high-temperature calcination at 1200° C. for 1 hour to obtain the high-strength geopolymer hollow microspheres (M3). The microspheres have a particle size of 250-300 μm, a compressive strength of 24 MPa, a wall thickness of 30 μm, and a density of 0.70 g/cm.sup.3.

Embodiment 4

(13) High-Strength Geopolymer Hollow Microspheres, and a Preparation Method thereof.

(14) 1.4 g of sodium hydroxide (NaOH), 6 g of sodium silicate (Na.sub.2SiO.sub.3.9H.sub.2O) and 4 g of sodium chloride (NaCl) were dissolved in 10 g of water to form a solution A, and 12 g of metakaolin was added to the solution A, stirred and uniformly mixed to form a slurry B, the slurry B was added to a corn oil, wherein the slurry B accounts for 30% of a volume of the corn oil. The slurry B was stirred to disperse into balls, a stirring speed was 700 r/min, a stirring time was 0.5 hours, and a temperature of the corn oil is 85° C. A filtration was performed to obtain geopolymer microspheres I. The geopolymer microspheres I were washed, and then subjected to a high-temperature calcination at 900° C. for 2 hours to obtain the high-strength geopolymer hollow microspheres (M4). The microspheres have a particle size of 100-200 μm, a compressive strength of 26 MPa, a wall thickness of 25 μm, and a density of 0.65 g/cm.sup.3.

Embodiment 5

(15) High-Strength Geopolymer Hollow Microsphere, and a Preparation Method thereof.

(16) 1.5 g of sodium hydroxide (NaOH), 5 g of sodium silicate (Na.sub.2SiO.sub.3.9H.sub.2O) and 3 g of sodium chloride (NaCl) were dissolved in 10 g of water to form a solution A, and 10 g of metakaolin was added to the solution A, stirred and uniformly mixed to form a slurry B, the slurry B was added to a corn oil, wherein the slurry B accounts for 10% of a volume of the corn oil. The slurry B was stirred to disperse into balls, a stirring speed was 550 r/min, a stirring time was 2 hours, and a temperature of the corn oil is 60° C. A filtration was performed to obtain geopolymer microspheres I. The geopolymer microspheres I were washed, and then subjected to a high-temperature calcination at 900° C. for 2 hours to obtain the high-strength geopolymer hollow microspheres (M5). The microspheres have an average particle size of 200 μm, a wall thickness of 20-30 μm. The micrographs of the microspheres M5 are shown in FIG. 1 and FIG. 2.

Embodiment 6

(17) A Method of Preparing Phase Change Energy Storage Microspheres.

(18) The high-strength geopolymer hollow microspheres (M5) were used as carriers, phase change materials, i.e., paraffin (C18-30), were absorbed into hollows of the carrier microspheres by a vacuum suction. The geopolymer microspheres and the paraffin in a molten state were placed in an open container, the open container was placed in a vacuum chamber. Under a pressure of −0.1 MPa, a vacuumization was performed for 60 min, the microspheres were moved from the vacuum chamber to a 4° C. refrigerator for freezing until the paraffin become solid to obtain microspheres carrying the phase change materials (paraffin-geopolymer microspheres). A mass of the paraffin is 15% of that of the hollow microspheres. The paraffin-geopolymer microspheres were mixed with an ambient cured waterborne epoxy resin to make the epoxy resin coat on surfaces of the microspheres, a mass of the epoxy resin is 10% of that of the hollow microspheres. Subsequently, a calcium carbonate powder dispersant with a particle size of 1200 mesh was added, and a stirring was performed at 100 r/min for 0.5 hours to disperse the microspheres. After the epoxy resin was solidified, the superfluous powder dispersant was screened to obtain the phase energy storage microsphere sample 1.

Embodiment 7

(19) A Method of Preparing Phase Change Energy Storage Microspheres.

(20) The high-strength geopolymer hollow microspheres (M5) were used as carriers, phase change materials (C18-30) were absorbed into hollows of the carrier microspheres by a vacuum suction. The geopolymer hollow microspheres and the paraffin in a molten state were placed in an open container, the open container was placed in a vacuum chamber. Under a pressure of −0.1 MPa, a vacuumization was performed for 30 min, the microspheres were moved from the vacuum chamber to a 4° C. refrigerator for freezing until the paraffin become solid to obtain microspheres carrying the phase change materials (paraffin-geopolymer microspheres). A mass of the paraffin is 10% of that of the hollow microspheres. The paraffin-geopolymer microspheres were mixed with ambient cured oily epoxy resin to make the epoxy resin coat on surfaces of the microspheres, a mass of the epoxy resin is 8% of that of the hollow microspheres. Subsequently, a graphite powder dispersant with a particle size of 1500 mesh was added, and a stirring was performed at 150 r/min for 1 hour to disperse the microspheres. After the epoxy resin was solidified, the superfluous powder dispersant was screened to obtain the phase energy storage microsphere sample 2.

Embodiment 8

(21) A Method of Preparing Phase Change Energy Storage Microspheres.

(22) The high-strength geopolymer hollow microspheres (M5) were used as carriers, phase change materials (C18-30) were absorbed into hollows of the carrier microspheres by a vacuum suction. The geopolymer hollow microspheres and the paraffin in a molten state were placed in an open container, the open container was placed in a vacuum chamber. Under a pressure of −0.1 MPa, a vacuumization was performed for 40 min, the microspheres were moved from the vacuum chamber to a 4° C. refrigerator for freezing until the paraffin become solid to obtain microspheres carrying the phase change materials (paraffin-geopolymer microspheres). A mass of the paraffin is 12% of that of the hollow microspheres. The paraffin-geopolymer microspheres were mixed with an ambient cured waterborne epoxy resin to make the epoxy resin coat on surfaces of the microspheres, a mass of the epoxy resin is 12% of that of the hollow microspheres. Subsequently, a silicon powder dispersant with a particle size of 1500 mesh was added, and a stirring was performed at 150 r/min for 0.5 hours to disperse the microspheres. After the epoxy resin was solidified, the superfluous powder dispersant was screened to obtain the phase energy storage microsphere sample 3.

Embodiment 9

(23) A Method of Preparing Phase Change Energy Storage Microspheres.

(24) The high-strength geopolymer hollow microspheres (M5) were used as carriers, phase change materials (C18-30) were absorbed into hollows of the carrier microspheres by a vacuum suction. The geopolymer hollow microspheres and the paraffin in s molten state were placed in an open container, the open container was placed in a vacuum chamber. Under a pressure of −0.1 MPa, a vacuumization was performed for 80 min, the microspheres were moved from the vacuum chamber to a 4° C. refrigerator for freezing until the paraffin become solid to obtain microspheres carrying the phase change materials (paraffin-geopolymer microspheres). A mass of the paraffin is 18% of that of the hollow microspheres. The paraffin-geopolymer microspheres were mixed with an ambient cured oily epoxy resin to make the epoxy resin coat on surfaces of the microspheres, a mass of the epoxy resin is 15% of that of the hollow microspheres. Subsequently, an ultrafine slag powder dispersant with a particle size of 1500 mesh was added, and a stirring was performed at 300 r/min for 1.5 hours to disperse the microspheres. After the epoxy resin was solidified, the superfluous powder dispersant was screened to obtain the phase energy storage microsphere sample 4.

(25) FIG. 3 is a micrograph showing the phase change energy storage microsphere sample 1. It can be seen that the surfaces of the microspheres are uniformly covered with the epoxy resin, and after dispersion by the calcium carbonate powder dispersant, the microspheres have good dispersion effect and no agglomeration phenomenon occurs. Broken microspheres in the phase change energy storage microsphere sample 1 were selected for a microscopic observation. As shown in FIG. 4, the paraffin was successfully absorbed into the geopolymer hollow microsphere.

(26) Evaluations of effects of the above different phase change energy storage microsphere samples on a hydration exothermic temperature and a compressive strength of a cement slurry are shown in Table 1.

(27) TABLE-US-00001 TABLE 1 Effects of phase change energy storage microsphere samples on cement slurry performance compressive strength hydration exothermic after curing at 75° C. sample temperature peak/° C. for 24 h/MPa comparison sample: pure 103.7 28.5 cement slurry cement slurry + 5% 83.3 27.2 (mass ratio) sample 1 cement slurry + 10% 71.5 23.8 (mass ratio) sample 2 cement slurry + 5% 80.5 26.8 (mass ratio) sample 3 cement slurry + 10% 74.6 25.4 (mass ratio) sample 4

(28) The evaluation results show that an addition of phase change energy storage microspheres significantly reduces the cement hydration exothermic temperature peak, and has little effect on the compressive strength of cement stone.

(29) Although the specific embodiments of the present invention have been described above in conjunction with the drawings, it is not intended to limit the scope of protection of the present invention. On the basis of the technical solutions of the present invention, various modifications or variations that can be made by those skilled in the art without any creative effort are still within the scope of protection of the present invention.