A phase change heat storage foam concrete and its preparation process

Abstract

The present invention discloses a phase change heat storage foam concrete, which relates to the technical field of foam concrete and is made from the following raw materials in parts by weight: 110 parts of portland cement, 27 - 30 parts of fly ash, 10 - 18 parts of phase change material, 1 - 2 parts of foaming agent, 1 - 2 parts of foam stabilizer, 45 - 48 parts of thermal insulation aggregate, 48 - 50 parts of water, and 1 - 1.5 parts of polycarboxylate water reducer. The prepared concrete not only has high strength but also excellent heat storage and insulation performance.

Description

Technical Field

[0001] The present invention relates to the technical field of foamed concrete, and in particular to a phase change heat storage foamed concrete and a preparation process thereof. Background Art

[0002] Foamed concrete is a concrete product with a large number of pores formed by introducing gases such as air into the concrete slurry, having a certain structure. It is light in weight, and has heat preservation, fire resistance, heat insulation, sound insulation and earthquake resistance, and is widely used in heat insulation structures such as building peripheries and roofs, and is used as an energy-saving material. The improvement of the heat insulation performance of foamed concrete mainly improves its energy-saving performance by increasing the porosity of the foamed concrete. However, increasing the porosity will lead to a decrease in its strength and easy cracking. Therefore, in the prior art, in order to increase the energy-saving performance of foamed concrete, the raw material components are optimized. For example, some reinforcing agents such as anti-cracking fibers are doped, which can improve its compressive strength on the basis of increasing the energy-saving effect of foamed concrete. However, only by increasing the porosity to improve its energy-saving performance, the improvement effect is limited.

[0003] At present, in the prior art, there is research on applying phase change materials to foamed concrete to enhance the energy-saving effect of foamed concrete. Li Gang et al. mentioned in the article "Research on the Preparation and Heat Transfer Characteristics of Phase Change Foamed Concrete Blocks": The east, south and west facing exterior walls of buildings in Guangzhou area are successively made of phase change foamed concrete with the content of composite phase change materials being 15%, 15% and 25% respectively, which has a good heat insulation effect and is obvious in reducing the indoor temperature fluctuation. It shows that applying phase change materials to concrete is effective for energy saving. However, the main problems existing in the preparation of phase change heat storage foamed concrete are: 1. The addition of phase change materials affects the strength of the concrete; 2. The heat storage and heat insulation effect is limited. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a phase change heat storage foamed concrete aiming at the deficiencies of the prior art. The prepared foamed concrete not only has high strength but also has excellent heat storage and heat insulation performance.

[0005] To achieve the above purpose, the present invention adopts the following technical solutions:

[0006] A phase change heat storage foamed concrete is made from the following raw materials in parts by weight: 110 parts of portland cement, 27 - 30 parts of fly ash, 10 - 18 parts of phase change material, 1 - 2 parts of foaming agent, 1 - 2 parts of foam stabilizer, 45 - 48 parts of heat preservation aggregate, 48 - 50 parts of water, and 1 - 1.5 parts of polycarboxylate water reducer.

[0007] Furthermore, the phase change material is prepared by the following steps:

[0008] (1) Mix zeolite powder and kaolin evenly according to a weight ratio of 1:1, then add a 10wt% polyvinyl alcohol solution accounting for 30% of the total mass of the above mixture for granulation. Heat the granules to 1000 - 1100 °C and calcine for 2 h to obtain porous granules;

[0009] (2) Immerse the porous granules and a citric acid solution with a concentration of 0.7 - 1 mol / L according to a weight ratio of 1:8 - 10 for 3 h, wash and dry to obtain modified porous granules;

[0010] (3) Heat the phase change paraffin to melt it. At the same time, place the modified porous granules in a reactor, evacuate to a vacuum degree of 0.05 - 0.06 MPa in the reactor, then drop the molten phase change paraffin onto the modified porous granules in the reactor. Meanwhile, control the temperature in the reactor to be 50 - 55 °C. After dropping, seal the reactor and ultrasonically oscillate for 30 min to obtain particulate matter. The weight ratio of the phase change paraffin to the modified porous granules is 1:2 - 3;

[0011] (4) Stir the above particulate matter, calcium chloride, sodium dodecylbenzenesulfonate and an appropriate amount of water evenly, and dropwise add sodium carbonate while stirring and reacting. After the reaction ends, wash, filter and dry to obtain the phase change material. The weight ratio of calcium chloride, sodium carbonate, sodium dodecylbenzenesulfonate to the particulate matter is 3:3:0.1:8 - 9.

[0012] Further, the particle size of the granulated particles in step (1) is 1 - 3 mm.

[0013] Further, the thermal insulation aggregate is prepared by the following steps:

[0014] (1) Mix steel slag, kaolin and feldspar according to a weight ratio of 2:1:1, ball mill them, then add 5 - 8% of white dextrin, 5 - 8% of dolomite and 30% of water, mix evenly, and extrude and granulate with a particle size of 3 - 6 mm;

[0015] (2) Dry the above particles at 70 - 80 °C and then conduct high-temperature calcination to obtain the thermal insulation aggregate.

[0016] Further, the foam stabilizer is composed of calcium stearate, sodium carboxymethyl cellulose and nano-calcium carbonate mixed according to a weight ratio of 1:1:0.5 - 1.

[0017] Further, in step (2), the high-temperature calcination is first to raise the temperature to 400 °C at a rate of 2 °C / min and hold for 30 min, then raise the temperature to 800 °C at a rate of 1 °C / min and hold for 30 min, and finally raise the temperature to 1150 °C at a rate of 3 °C / min and hold for 2 - 3 h.

[0018] A preparation process of phase change heat storage foam concrete includes the following steps:

[0019] (1) Mix the foaming agent with 20 times water and then foam it using a foaming machine;

[0020] (2) First, soak the thermal insulation aggregate in water for 1 h, then mix it evenly with portland cement, fly ash, phase change material, foam stabilizer, polycarboxylate water reducer and the remaining water, add the foam in step (1) and stir evenly, then cast and cure.

[0021] The beneficial effects of the present invention are as follows:

[0022] 1. The present application discloses a phase change heat storage foam concrete, which adopts a self-made phase change material and thermal insulation aggregate, greatly improving the heat preservation and heat storage performance of the concrete. The concrete has high strength and excellent heat preservation and heat storage performance.

[0023] 2. The phase change material is prepared by loading paraffin on modified porous particles and then capped with calcium carbonate. The modified porous particles are first granulated from zeolite powder and kaolin with the addition of a binder polyvinyl alcohol, and then calcined into porous particles. After zeolite and kaolin are calcined at high temperature, components such as Al and Si in them form a mullite phase skeleton after calcination to ensure strength, while the water and organic substances in them form a porous channel structure after calcination. After further impregnation with citric acid, the roughness of its pore channel structure is further increased, and the loading amount of paraffin is increased. Then, by vacuum impregnating the molten solution of phase change paraffin, paraffin is adsorbed into the interior of the modified porous particles. Then, the particles loaded with paraffin are evenly dispersed in calcium chloride solution, and sodium carbonate is added drop by drop to precipitate calcium carbonate on the surface of the particles, playing a capping role, which can ensure that paraffin does not leak and ensure that it does not affect the strength while increasing the heat preservation and heat storage performance of the concrete.

[0024] 3. The thermal insulation aggregate is prepared by ball milling, extruding and granulating steel slag, kaolin and feldspar and then calcining at high temperature. The extruded and granulated particles have a large density and dense particle contact. The silica, silica, etc. in steel slag, kaolin and feldspar form a glass phase skeleton after high-temperature sintering. During the heating process, water is gradually lost, and then dextrin and dolomite are gradually decomposed. By controlling the heating rate, gas can be slowly discharged, reducing the cracking or deformation of the pore channels inside the thermal insulation aggregate, ensuring the mechanical strength of the thermal insulation aggregate, and preparing a thermal insulation aggregate with high skeleton strength and a porous structure inside, which can further increase the heat preservation performance of the concrete.

[0025] 4. A foam stabilizer is also added to the concrete raw materials. The foam stabilizer is a mixture of calcium stearate, sodium carboxymethyl cellulose and nano calcium carbonate. Calcium stearate can increase the hydrophobicity of the particles in the cement slurry, make it and nano calcium carbonate adhere to the gas-liquid interface, increasing the stability of the foam, while sodium carboxymethyl cellulose can further increase the viscoelasticity of the foam. The compounding of these three components has a synergistic foam stabilizing effect. Description of the Drawings

[0026] Figure 1 It is the heating curve graph of the specimens of Examples 1-4 and Comparative Example 1. Detailed implementation manners

[0027] The following further describes the present application in combination with specific embodiments.

[0028] Embodiment 1

[0029] A phase change heat storage foamed concrete is made from the following raw materials in parts by weight: 110 parts of portland cement, 27 parts of fly ash, 10 parts of phase change material, 1 part of foaming agent, 1 part of foam stabilizer, 45 parts of thermal insulation aggregate, 48 parts of water, and 1 part of polycarboxylate water reducer.

[0030] The phase change material is prepared by the following steps:

[0031] (1) Mix zeolite powder and kaolin evenly according to a weight ratio of 1:1, add a 10wt% polyvinyl alcohol solution with a mass fraction of 30% of the total amount of the above mixture for granulation, and the particle size of the particles is 1 - 3mm. Heat the particles to 1000 - 1100°C and calcine for 2h to obtain porous particles;

[0032] (2) Immerse the porous particles and 0.7mol / L citric acid solution according to a weight ratio of 1:8 for 3h, wash and dry to obtain modified porous particles;

[0033] (3) Heat and melt the phase change paraffin. At the same time, place the modified porous particles in a reactor, evacuate to a vacuum degree of 0.05MPa in the reactor, then drop the molten phase change paraffin onto the modified porous particles in the reactor, while controlling the temperature in the reactor to be 50 - 55°C. After dropping, seal the reactor and ultrasonically oscillate for 30min to obtain particulate matter. The weight ratio of the phase change paraffin to the modified porous particles is 1:2;

[0034] (4) Stir the above particulate matter, calcium chloride, sodium dodecylbenzenesulfonate and an appropriate amount of water evenly, and dropwise add sodium carbonate for stirring reaction. After the reaction ends, wash, filter and dry to obtain the phase change material. The weight ratio of calcium chloride, sodium carbonate, sodium dodecylbenzenesulfonate and particulate matter is 3:3:0.1:8.

[0035] The thermal insulation aggregate is prepared by the following steps:

[0036] (1) Mix steel slag, kaolin and feldspar according to a weight ratio of 2:1:1, ball mill them, add 5% of white dextrin, 5% of dolomite and 30% of water based on the total amount of the above raw materials, mix evenly, and extrude and granulate with a particle size of 3 - 6mm;

[0037] (2) Dry the above particles at 70 - 80°C and then conduct high-temperature calcination. The high-temperature calcination is to first heat up to 400°C at a rate of 2°C / min and hold for 30min, then heat up to 800°C at a rate of 1°C / min and hold for 30min, and finally heat up to 1150°C at a rate of 3°C / min and hold for 2h to obtain the thermal insulation aggregate.

[0038] Among them, the foam stabilizer is composed of calcium stearate, sodium carboxymethyl cellulose and nano-calcium carbonate mixed in a weight ratio of 1:1:0.5; the phase change temperature of the phase change paraffin is 45 °C.

[0039] A preparation process of phase change heat storage foam concrete includes the following steps:

[0040] (1) The foaming agent is mixed with 20 times of water and then foamed by a foaming machine;

[0041] (2) First, the thermal insulation aggregate is soaked in water for 1 h, and then mixed evenly with portland cement, fly ash, phase change material, foam stabilizer, polycarboxylate water reducer and the remaining water, and the foam in step (1) is added for further stirring evenly, and then poured into a mold for curing.

[0042] Example 2

[0043] A kind of phase change heat storage foam concrete is made of the following raw materials in parts by weight: 110 parts of portland cement, 28 parts of fly ash, 12 parts of phase change material, 1.5 parts of foaming agent, 1.5 parts of foam stabilizer, 46 parts of thermal insulation aggregate, 49 parts of water, and 1.2 parts of polycarboxylate water reducer.

[0044] Among them, the phase change material is prepared by the following steps:

[0045] (1) Zeolite powder and kaolin are mixed evenly in a weight ratio of 1:1, and then granulated by adding a 10 wt% polyvinyl alcohol solution with a mass fraction of 30% of the total amount of the above mixture. The particle size of the particles is 1-3 mm, and the particles are heated to 1050 °C and calcined for 2 h to obtain porous particles;

[0046] (2) The porous particles are impregnated with a 0.8 mol / L citric acid solution in a weight ratio of 1:9 for 3 h, washed and dried to obtain modified porous particles;

[0047] (3) The phase change paraffin is heated and melted. At the same time, the modified porous particles are placed in a reactor, and the vacuum is pumped to a vacuum degree of 0.055 MPa in the reactor. Then, the melted phase change paraffin is dropped onto the modified porous particles in the reactor. At the same time, the temperature in the reactor is controlled at 50-55 °C. After dropping, the reactor is closed and ultrasonically oscillated for 30 min to obtain particulate matter. The weight ratio of the phase change paraffin to the modified porous particles is 1:2.5;

[0048] (4) The above particulate matter, calcium chloride, sodium dodecylbenzenesulfonate and an appropriate amount of water are stirred evenly, and dropped into sodium carbonate dropwise for stirring reaction. After the reaction is completed, it is washed, filtered and dried to obtain the phase change material. The weight ratio of calcium chloride, sodium carbonate, sodium dodecylbenzenesulfonate and particulate matter is 3:3:0.1:8.5.

[0049] The thermal insulation aggregate is prepared by the following steps:

[0050] (1) After mixing and ball-milling steel slag, kaolin and feldspar in a weight ratio of 2:1:1, 6% white dextrin, 6% dolomite and 30% water are added and mixed evenly, followed by extrusion granulation with a particle size of 3 - 6 mm;

[0051] (2) The above-mentioned particles are dried at 70 - 80 °C and then calcined at high temperature. The high-temperature calcination is carried out by first heating at a rate of 2 °C / min to 400 °C and holding for 30 min, then heating at a rate of 1 °C / min to 800 °C and holding for 30 min, and finally heating at a rate of 3 °C / min to 1150 °C and holding for 3 h to obtain heat-preserving aggregate.

[0052] The foam stabilizer is composed of calcium stearate, sodium carboxymethyl cellulose and nano calcium carbonate mixed in a weight ratio of 1:1:0.6.

[0053] The preparation process is the same as that of Example 1.

[0054] Example 3

[0055] A phase change heat storage foam concrete is made from the following raw materials in parts by weight: 110 parts of portland cement, 29 parts of fly ash, 15 parts of phase change material, 1.8 parts of foaming agent, 1.8 parts of foam stabilizer, 47 parts of heat-preserving aggregate, 49 parts of water, and 1.4 parts of polycarboxylate water reducer.

[0056] The phase change material is prepared by the following steps:

[0057] (1) After mixing zeolite powder and kaolin evenly in a weight ratio of 1:1, granulation is carried out by adding a 10 wt% polyvinyl alcohol solution with a mass fraction of 30% of the total amount of the above mixture. The particle size of the particles is 1 - 3 mm, and the particles are heated to 1100 °C and calcined for 2 h to obtain porous particles;

[0058] (2) The porous particles are impregnated with a 0.9 mol / L citric acid solution in a weight ratio of 1:9 for 3 h, washed and dried to obtain modified porous particles;

[0059] (3) The phase change paraffin is heated and melted. At the same time, the modified porous particles are placed in a reactor, and the vacuum is pumped to a vacuum degree of 0.06 MPa in the reactor. Then the melted phase change paraffin is dropped onto the modified porous particles in the reactor, while controlling the temperature in the reactor to be 50 - 55 °C. After dropping, the reactor is sealed and ultrasonically oscillated for 30 min to obtain particulate matter. The weight ratio of the phase change paraffin to the modified porous particles is 1:3;

[0060] (4) The above-mentioned particulate matter, calcium chloride, sodium dodecylbenzenesulfonate and an appropriate amount of water are stirred evenly, and then dropped into sodium carbonate dropwise for stirring reaction. After the reaction ends, it is washed, filtered and dried to obtain the phase change material. The weight ratio of calcium chloride, sodium carbonate, sodium dodecylbenzenesulfonate to the particulate matter is 3:3:0.1:8.5.

[0061] The heat-insulating aggregate is prepared by the following steps:

[0062] (1) After mixing and ball-milling steel slag, kaolin and feldspar according to a weight ratio of 2:1:1, 7% white dextrin, 7% dolomite and 30% water are added and mixed evenly, and then extrusion granulation is carried out, with the particle size being 3-6 mm;

[0063] (2) The above-mentioned particles are dried at 70-80 °C and then calcined at high temperature. The high-temperature calcination is to first increase the temperature to 400 °C at a rate of 2 °C / min and hold for 30 min, then increase the temperature to 800 °C at a rate of 1 °C / min and hold for 30 min, and finally increase the temperature to 1150 °C at a rate of 3 °C / min and hold for 2.5 h to obtain the heat-insulating aggregate.

[0064] The foam stabilizer is composed of calcium stearate, sodium carboxymethyl cellulose and nano-calcium carbonate mixed according to a weight ratio of 1:1:0.8.

[0065] The preparation process is the same as that of Example 1.

[0066] Example 4

[0067] A phase change heat storage foam concrete is made from the following raw materials in parts by weight: 110 parts of portland cement, 30 parts of fly ash, 18 parts of phase change material, 2 parts of foaming agent, 2 parts of foam stabilizer, 48 parts of heat-insulating aggregate, 50 parts of water, and 1.5 parts of polycarboxylate water reducer.

[0068] The phase change material is prepared by the following steps:

[0069] (1) After mixing zeolite powder and kaolin evenly according to a weight ratio of 1:1, 30% of the total mass of the above mixture of a 10 wt% polyvinyl alcohol solution is added for granulation, and the particle size of the particles is 1-3 mm. The particles are heated to 1100 °C and calcined for 2 h to obtain porous particles;

[0070] (2) The porous particles are impregnated with a 1 mol / L citric acid solution according to a weight ratio of 1:10 for 3 h, washed and dried to obtain modified porous particles;

[0071] (3) The phase change paraffin is heated and melted. At the same time, the modified porous particles are placed in a reactor, and the vacuum is pumped to a vacuum degree of 0.06 MPa in the reactor. Then the melted phase change paraffin is dropped onto the modified porous particles in the reactor, and at the same time, the temperature in the reactor is controlled at 50-55 °C. After dropping, the reactor is closed and ultrasonically oscillated for 30 min to obtain particulate matter. The weight ratio of the phase change paraffin to the modified porous particles is 1:2;

[0072] (4) Stir the above-mentioned particulate matter, calcium chloride, sodium dodecylbenzenesulfonate and appropriate amount of water evenly, dropwise add sodium carbonate and stir for reaction. After the reaction is completed, wash, filter by suction and dry to obtain the phase change material. The weight ratio of calcium chloride, sodium carbonate, sodium dodecylbenzenesulfonate and particulate matter is 3:3:0.1:9.

[0073] The thermal insulation aggregate is prepared by the following steps:

[0074] (1) Mix steel slag, kaolin and feldspar in a weight ratio of 2:1:1, grind them in a ball mill, then add 8% white dextrin, 8% dolomite and 30% water, mix evenly, and extrude and granulate with a particle size of 3-6 mm;

[0075] (2) Dry the above-mentioned particles at 70-80 °C and then calcine them at high temperature. The high-temperature calcination is to first raise the temperature to 400 °C at a rate of 2 °C / min and hold for 30 min, then raise the temperature to 800 °C at a rate of 1 °C / min and hold for 30 min, and finally raise the temperature to 1150 °C at a rate of 3 °C / min and hold for 3 h to obtain the thermal insulation aggregate.

[0076] The foam stabilizer is composed of calcium stearate, sodium carboxymethylcellulose and nano-calcium carbonate mixed in a weight ratio of 1:1:1.

[0077] The preparation process is the same as that of Example 1.

[0078] Comparative Example 1

[0079] Comparative Example 1 is a comparative example of Example 4, and no phase change material is added to the foam concrete raw materials.

[0080] Performance detection

[0081] Detect the dry density, 28-day compressive strength and thermal conductivity of the foam concrete prepared in Examples 1-4 and Comparative Example 1. The dry density test refers to GB / T 54863-2001, and the specimen specification is 70.7*70.7*70.7 mm. The thermal conductivity is measured according to GB / T10294 "Determination of Steady-State Thermal Resistance and Related Characteristics of Thermal Insulation Materials - Heat Flow Meter Method", and the specimen specification is 300 mm×300 mm×50 mm. The results are shown in Table 1.

[0082] Detect the leakage performance of paraffin in the phase change materials prepared in Examples 1-4. The test method is: place 20 g of the phase change materials prepared in Examples 1-4 on filter paper, heat them to 60 °C and melt them repeatedly 50 times, and test the leakage situation. The leakage rate is the ratio of the mass lost in the melting test to the mass of the phase change material before the test. The results are shown in Table 1.

[0083] Test the thermal conductivity of the concrete specimens prepared in Examples 1-4 of this application. Place the 40*40*40 mm specimens in the same ambient temperature for 1 day to ensure that all sample blocks have the same initial temperature. Before the heating test, place all sample blocks in heat insulation molds made of EPS insulation boards to isolate the influence of the ambient temperature, and place each sample block on a digital display heating plate to heat the bottom of the specimen simultaneously. Detect the top surface temperature and draw a curve, see Figure 1 .

[0084] Table 1 Performance test data

[0085]

[0086] As can be seen from Table 1, the concrete specimens prepared from the raw materials of Examples 1-4 of this application have good uniformity, high strength, and the 28-day compressive strength can reach 9.3-9.9 Mpa. Moreover, they have excellent heat insulation performance; and the paraffin in the phase change material has a good loading effect and a low leakage rate.

[0087] Comparative Example 1 is a comparative example of Example 4 without adding a phase change material. Although its strength is slightly higher than that of Example 4, its thermal conductivity is much higher than that of Example 4, indicating that the added phase change material in this application can improve the heat insulation performance of the material and has little effect on the strength.

[0088] Figure 1 is the heating curve graph of the blocks in Examples 1-4 and Comparative Example 1. From Figure 1 it can be seen that the blocks in Examples 1-4 reach the maximum heat storage capacity near 45 min, 60 min, 75 min, and 90 min, respectively, and there is a heating pause. While Comparative Example 1 does not add a phase change material and there is no heating pause, and its temperature gradually increases as the block is heated. This shows that the concrete prepared in this application can buffer the indoor and outdoor temperature changes and has excellent heat storage performance. Its phase change temperature is between 36-42 °C, which is suitable for use as a building energy-saving material.

[0089] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Any other modifications or equivalent replacements made by those of ordinary skill in the art to the technical solutions of the present invention shall be covered by the scope of the claims of the present invention as long as they do not depart from the spirit and scope of the technical solutions of the present invention.

Claims

1. A phase change thermal storage foam concrete, characterized in that: Made from the following raw materials in parts by weight: 110 parts of Portland cement, 27-30 parts of fly ash, 10-18 parts of phase change material, 1-2 parts of foaming agent, 1-2 parts of foam stabilizer, 45-48 parts of thermal insulation aggregate, 48-50 parts of water, 1-1.5 parts of polycarboxylate water reducer; The phase change material is prepared by the following steps: (1) After zeolite powder and kaolin are uniformly mixed in a weight ratio of 1:1, 30% of the total amount of the above mixture and a 10wt% polyvinyl alcohol solution are added to granulate the particles, and the particles are heated to 1000-1100°C and calcined for 2 hours to obtain porous particles; (2) immersing the porous particles in a citric acid solution with a concentration of 0.7-1 mol / L at a weight ratio of 1:8-10 for 3 hours, washing and drying to obtain modified porous particles; (3) heating and melting the phase change wax, placing the modified porous particles in a reactor, evacuating the reactor to a vacuum degree of 0.05-0.06 MPa, and then dripping the molten phase change wax onto the modified porous particles in the reactor, while controlling the temperature in the reactor to 50-55° C., sealing the reactor after dripping, and ultrasonically oscillating for 30 minutes to obtain particles, wherein the weight ratio of the phase change wax to the modified porous particles is 1:2-3; (4) The above-mentioned granules, calcium chloride, sodium dodecylbenzene sulfonate and an appropriate amount of water are stirred evenly, and sodium carbonate is added dropwise to stir for reaction. After the reaction is completed, the phase change material is washed, filtered and dried to obtain a phase change material, wherein the weight ratio of calcium chloride, sodium carbonate, sodium dodecylbenzene sulfonate and granules is 3:3:0.1:8-9; The foam stabilizer is a mixture of calcium stearate, sodium carboxymethyl cellulose and nano calcium carbonate in a weight ratio of 1:1:0.5-1; The thermal insulation aggregate is prepared by the following steps: (1) After steel slag, kaolin and feldspar are mixed and ball-milled in a weight ratio of 2:1:1, 5-8% white dextrin, 5-8% dolomite and 30% water are added and mixed evenly, and then extruded into granules with a particle size of 3-6 mm; (2) The above particles are dried at 70-80°C and then calcined at high temperature to obtain thermal insulation aggregate.

2. The phase change thermal storage foam concrete according to claim 1, characterized in that: The particle size of the granulated particles in the phase change material preparation step (1) is 1-3 mm.

3. The phase change thermal storage foam concrete according to claim 1, characterized in that: In the step (2) of preparing the thermal insulation aggregate, the high temperature calcination is firstly heated to 400°C at a rate of 2°C / min and kept at that temperature for 30 minutes, then heated to 800°C at a rate of 1°C / min and kept at that temperature for 30 minutes, and finally heated to 1150°C at a rate of 3°C / min and kept at that temperature for 2-3 hours.

4. A process for preparing the phase change thermal storage foam concrete according to claim 1, characterized in that: The following steps are involved: (1) The foaming agent is mixed with 20 times water and then foamed using a foaming machine; (2) First, soak the thermal insulation aggregate in water for 1 hour, then mix it evenly with silicate cement, fly ash, phase change material, foam stabilizer, polycarboxylic acid water reducer and the remaining water, add the foam in step (1) and stir it evenly, and then inject and cure it.

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