Precision casting unshelling waste-based phase change energy storage material and preparation method thereof

Abstract

The invention discloses a phase change energy storage material based on precision casting unshelling waste. The phase change energy storage material comprises the following raw materials in parts by weight: 50-75 parts of precision casting unshelling waste, 5-40 parts of fly ash, 4-20 parts of a phase change agent, 3-6 parts of water and 6-16 parts of a binder, the preparation method comprises the following steps: (1) firstly drying the precision casting unshelling waste and the fly ash, and then adding the phase change agent for dry mixing; (2) adding water and a binder, and carrying out wet mixing and ball milling; (3) pressure forming; (4) drying; and (5) sintering. The energy storage material prepared by the invention has relatively high energy density, relatively low cost and relatively high safety, and is a phase change energy storage material which is stable in chemical performance and excellent in heat conduction and heat storage performance. According to the invention, waste is turned into wealth, the cost of the energy storage material is greatly reduced, and the application of the phase change energy storage brick is substantially developed. In the future, along with the further maturation of the technology and the profound enthusiasm of environmental consciousness, the zero emission of the precision casting shelling waste can be gradually realized, and a greener, more efficient and sustainable development road is brought to the casting industry.

Description

Technical Field

[0001] The invention relates to the technical field of waste utilization and energy storage materials, and more particularly to a precision casting shelling waste-based phase change energy storage material and a preparation method thereof. Background Art

[0002] In recent years, with the rapid development of my country's industry and technological progress, the foundry industry is facing unprecedented opportunities and challenges. Especially in high-tech fields such as aerospace, the demand for precision castings is growing, which has driven the development of castings towards larger sizes, more complex structures, thinner wall thickness and more intelligent directions. In this process, a key factor cannot be ignored-60% of the casting quality depends on the shell material used in the casting process.

[0003] With the continuous enhancement of environmental awareness, green casting and clean production have gradually become an inevitable trend in the research and development of casting technology. In order to achieve this goal, we must reduce the generation of waste from the source, among which precision casting shelling waste accounts for more than 90% of the emissions in the casting production process. The raw materials of precision casting shelling waste are mainly used in the forming of aerospace precision castings such as alloy steel, high-temperature alloy, magnesium, aluminum, titanium light alloy castings, etc. Its physical and chemical properties are stable, the composition is complex, and it is difficult to recycle. However, due to its high price and excellent performance, it has a high recycling value. Therefore, how to achieve zero emissions of precision casting shelling waste has become the core issue of green casting.

[0004] At present, with the increasingly stringent requirements of the country's environmental protection regulations, the recycling and reuse of precision casting shelling waste has not only been widely recognized by the business community, but has also begun to be actively applied to actual production. This recycling can not only reduce costs, but also effectively reduce environmental pollution and promote the sustainable development of resources.

[0005] Scholars at home and abroad have begun to study the utilization of foundry waste shell resources and have achieved certain results. Waste foundry shells are mostly used as raw materials for low value-added products such as concrete, fillers, and building blocks in the construction industry, or used to prepare refractory materials such as lightweight aggregates, clay bricks, and as raw materials for preparing ceramic-based composite materials. Although these products have achieved waste recycling, they are still non-renewable and not environmentally friendly, and the added value of the prepared products is low. The refractory properties of the waste shells are not fully utilized, and they cannot be produced systematically.

[0006] Phase change energy storage materials refer to materials that store and release energy by changing the physical properties of materials at a certain temperature. They exist in three forms, namely solid-liquid, liquid-gas and solid-solid phase change. The working mechanism of the object is: when the external temperature is greater than the phase change temperature, the material changes from solid to liquid and absorbs heat; when the ambient temperature is lower than the phase change temperature, the material changes from liquid to solid and maintains the surrounding temperature by releasing heat. During phase change, the heat absorption and release of the material are tens or even hundreds of times higher than that of the single phase.

[0007] Phase change heat storage technology can alleviate the contradiction of time-space mismatch between energy supply and demand, and has broad application prospects in improving energy efficiency, protecting the environment, "shifting peaks and filling valleys", utilizing solar energy, recycling waste heat and waste heat, heating and air conditioning in industrial and civil buildings, etc. Establishing a multi-industry collaborative precision casting shelling waste recycling system to make "green +" a new economic growth point; combining the development trend of "digital expansion", establishing a precision casting shelling waste database and information exchange system, improving the efficiency of supervision and service industries, and improving the utilization rate of the entire chain of precision casting shelling waste resources are the focus of research at home and abroad.

[0008] Therefore, how to use precision casting shelling waste for phase change energy storage materials is a problem that technicians in this field need to solve urgently. Summary of the invention

[0009] In view of this, the object of the present invention is to provide a precision casting shelling waste-based phase change energy storage material and a preparation method thereof to address the deficiencies in the prior art.

[0010] In order to achieve the above object, the present invention adopts the following technical solution:

[0011] A precision casting shelling waste-based phase change energy storage material comprises the following raw materials in parts by weight: 50-75 parts of precision casting shelling waste, 5-40 parts of fly ash, 4-20 parts of phase change agent, 3-6 parts of water and 6-16 parts of binder.

[0012] Preferably, the composition comprises: 73 parts of precision casting shelling waste, 8 parts of fly ash, 4 parts of phase change agent, 3 parts of water and 16 parts of binder.

[0013] Preferably, the composition is: 67 parts of precision casting shelling waste, 17 parts of fly ash, 10 parts of phase change agent, 4 parts of water and 12 parts of binder.

[0014] Preferably, the composition is: 60 parts of precision casting shelling waste, 26 parts of fly ash, 15 parts of phase change agent, 5 parts of water and 9 parts of binder.

[0015] Preferably, the ingredients are: 53 parts of precision casting shelling waste, 35 parts of fly ash, 20 parts of phase change agent, 6 parts of water and 6 parts of binder.

[0016] Furthermore, the particle sizes of the above-mentioned precision casting shelling waste and fly ash are both 20-200 meshes.

[0017] A further beneficial effect of adopting the above method is that the present invention uses precision casting shelling waste as raw material and adds a certain proportion of fly ash, thereby increasing the overall mechanical properties and thermal properties of the phase change energy storage material.

[0018] Furthermore, the phase change agent is at least one of paraffin, polyol, water and inorganic salt.

[0019] Furthermore, the binder is at least one of polyvinyl alcohol aqueous solution, water glass and phenolic resin. Furthermore, the mass concentration of the polyvinyl alcohol aqueous solution is 8%; the mass ratio of the polyvinyl alcohol aqueous solution to the water glass is 1:2; the mass ratio of the polyvinyl alcohol aqueous solution to the phenolic resin is 1:1; the mass ratio of the water glass to the phenolic resin is 1:1; the mass ratio of the polyvinyl alcohol aqueous solution, the water glass and the phenolic resin is 1:1:1.

[0020] A further beneficial effect of the above method is that polyvinyl alcohol, water glass and phenolic resin are commonly used binders and are relatively easy to obtain.

[0021] A method for preparing a precision casting shelling waste-based phase change energy storage material, specifically comprising the following steps:

[0022] (1) firstly drying the precision casting shelling waste and fly ash, and then adding a phase change agent for dry mixing to obtain a base material;

[0023] (2) adding water and a binder to the base material, wet mixing, and ball milling to obtain a mixed material;

[0024] (3) pressurizing the mixed material to obtain a pressurized material;

[0025] (4) drying the pressurized material to obtain a dried material;

[0026] (5) Sintering the dried material to obtain the precision casting shelling waste-based phase change energy storage material.

[0027] Furthermore, in the above step (1), the drying equipment is a constant temperature drying oven, the temperature is 30° C., and the time is 2-4 hours; the dry mixing equipment is a roller sand mixer, and the time is 3 minutes.

[0028] A further beneficial effect of the above method is that the mixing method of the present invention is simple and does not require pretreatment, and the prepared energy storage materials are all inorganic-inorganic composites, so that the recycling rate of precision casting shelling waste reaches 100%.

[0029] Furthermore, in the above step (2), the wet mixing time is 3-5 minutes; the ball milling equipment is a drum ball mill, the rotation speed is 800r / min, and the time is 8 minutes.

[0030] Furthermore, in the above step (3), the equipment for pressure molding is a press, the pressure is 60 MPa, the time is 30 s, and the compaction strength is 0.1-0.4 MPa.

[0031] Furthermore, in the above step (4), the drying equipment is a drying oven, the temperature is 180-250° C., and the time is 2-4 hours.

[0032] Furthermore, in the above step (5), the sintering equipment is a box-type resistance furnace, the heating rate is 5-10°C / min, the temperature is 800-1000°C, and the time is 5-8h.

[0033] A further beneficial effect of adopting the above is that the present invention uses precision casting shelling waste as a matrix of energy storage material through a simple sintering process, achieving a phase change of 50-800°C or even lower temperature, and various performance indicators meet the design requirements, and can be used as a heat storage material.

[0034] It can be seen from the above technical solution that compared with the prior art, the beneficial effects of the present invention are as follows:

[0035] 1. The recycling of precision casting shelling waste is regarded as an important resource conservation and environmental protection measure, especially in the field of preparing energy storage materials. The present invention can not only realize the efficient utilization of resources, but also provide a new way for energy storage. Through a carefully designed processing flow, it is transformed into a new material with high-efficiency energy storage characteristics.

[0036] 2. The precision casting shelling waste of the present invention does not require additional pretreatment, and only needs to be crushed in a grinding wheel sand mixer and the particle size is controlled to be 20-200 mesh. The combination of precision casting shelling waste, fly ash and adhesive is completed by simple stirring and sintering. After the precision casting shelling waste is recycled, its refractory performance will be significantly improved. Compared with the new casting sand, its fire resistance limit is significantly enhanced, which can effectively reduce the deformation, sintering, and sand sticking of castings, and greatly improve the surface quality and dimensional accuracy of castings. This not only means an improvement in product quality, but also can reduce the amount of waste and save casting costs. The present invention also embodies a sense of responsibility for environmental protection, reduces the consumption of natural resources and the pressure of waste disposal. Therefore, the method of recycling treatment adopted in the present invention is not only beneficial to economic benefits, but also helps to promote sustainable development and green production.

[0037] 3. The energy storage material prepared by the present invention has high energy density, low cost and high safety. It is a phase change energy storage material with stable chemical properties, excellent thermal conductivity and heat storage performance. The present invention will realize the transformation of waste into treasure, greatly reduce the cost of energy storage materials, and make substantial progress in the application of phase change energy storage bricks. In the future, with the further maturity of technology and the deepening of environmental awareness, zero emission of precision casting shelling waste will gradually become a reality, bringing a more green, efficient and sustainable development path to the foundry industry.

[0038] 4. This invention not only reflects the efficient reuse of waste resources, but also demonstrates a new idea for promoting sustainable development in the field of materials science. Through the development of this new energy storage material, it is expected to play an important role in future energy storage technology and contribute to the widespread application of green energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is a physical picture of the drying material in step (4) of Example 1;

[0040] Figure 2 This is a physical picture of the drying material in step (4) of Example 2;

[0041] Figure 3 This is a physical picture of the drying material in step (4) of Example 3;

[0042] Figure 4 This is a physical picture of the drying material in step (4) of Example 4. DETAILED DESCRIPTION

[0043] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] Example 1

[0045] Precision casting shelling waste-based phase change energy storage material, including the following raw materials by weight: 73kg of 200-mesh precision casting shelling waste, 8kg of 200-mesh fly ash, 4kg of paraffin, 3kg of water, and 16kg of 8% mass concentration of polyvinyl alcohol aqueous solution;

[0046] The method for preparing the above-mentioned precision casting shelling waste-based phase change energy storage material specifically comprises the following steps:

[0047] (1) First, the precision casting shelling waste and fly ash are placed in a 30°C constant temperature drying oven and dried for 2 hours, and then added with paraffin wax to a roller sand mixer for dry mixing for 3 minutes to obtain a base material;

[0048] (2) adding water and polyvinyl alcohol aqueous solution to the substrate, wet mixing for 3 minutes, adding the substrate and 20 zirconium oxide balls with a diameter of 5 mm to a drum ball mill, and ball milling at a speed of 800 r / min for 8 minutes to obtain a mixed material;

[0049] (3) The mixed material is loaded into a mold, added to a press, and pressed using a Φ50 mm pressure head at a pressure of 60 MPa for 30 seconds and a compaction strength of 0.2 MPa to obtain a pressurized material;

[0050] (4) placing the pressurized material in a drying oven at 180° C. and drying for 4 h to obtain a dry material;

[0051] (5) The dried material is placed in a box-type resistance furnace, heated to 800°C at a heating rate of 5°C / min, and sintered for 5 hours to obtain a precision casting shelling waste-based phase change energy storage material.

[0052] Example 2

[0053] Precision casting shelling waste-based phase change energy storage material, including the following raw materials by weight: 67 kg of 200-mesh precision casting shelling waste, 17 kg of 200-mesh fly ash, 10 kg of paraffin, 4 kg of water, and 12 kg of 8% polyvinyl alcohol aqueous solution;

[0054] The method for preparing the above-mentioned precision casting shelling waste-based phase change energy storage material specifically comprises the following steps:

[0055] (1) First, the precision casting shelling waste and fly ash were placed in a 30°C constant temperature drying oven and dried for 3 hours, and then dry-mixed with a paraffin roller sand mixer for 3 minutes to obtain a base material;

[0056] (2) adding water and polyvinyl alcohol aqueous solution to the substrate, wet mixing for 3 minutes, adding the substrate and 20 zirconium oxide balls with a diameter of 5 mm to a drum ball mill, and ball milling at a speed of 800 r / min for 8 minutes to obtain a mixed material;

[0057] (3) The mixed material is loaded into a mold, added to a press, and pressed using a Φ50 mm pressure head at a pressure of 60 MPa for 30 seconds and a compaction strength of 0.2 MPa to obtain a pressurized material;

[0058] (4) placing the pressurized material in a drying oven at 200° C. for 3 h to obtain a dry material;

[0059] (5) The dried material is placed in a box-type resistance furnace, heated to 900°C at a heating rate of 5°C / min, and sintered for 6 hours to obtain a precision casting shelling waste-based phase change energy storage material.

[0060] Example 3

[0061] Precision casting shelling waste-based phase change energy storage material, including the following raw materials by weight: 60kg of 200-mesh precision casting shelling waste, 26kg of 200-mesh fly ash, 15kg of paraffin, 5kg of water, and 9kg of 8% mass concentration polyvinyl alcohol aqueous solution;

[0062] The method for preparing the above-mentioned precision casting shelling waste-based phase change energy storage material specifically comprises the following steps:

[0063] (1) First, the precision casting shelling waste and fly ash were placed in a 30°C constant temperature drying oven and dried for 4 hours, and then dry-mixed with a paraffin roller sand mixer for 3 minutes to obtain a base material;

[0064] (2) adding water and polyvinyl alcohol aqueous solution to the substrate, wet mixing for 3 minutes, adding the substrate and 20 zirconium oxide balls with a diameter of 5 mm to a drum ball mill, and ball milling at a speed of 800 r / min for 8 minutes to obtain a mixed material;

[0065] (3) The mixed material is loaded into a mold, added to a press, and pressed using a Φ50 mm pressure head at a pressure of 60 MPa for 30 seconds and a compaction strength of 0.3 MPa to obtain a pressurized material;

[0066] (4) placing the pressurized material in a drying oven at 250° C. and drying for 4 h to obtain a dry material;

[0067] (5) The dried material is placed in a box-type resistance furnace, heated to 1000°C at a heating rate of 10°C / min, and sintered for 8 hours to obtain a precision casting shelling waste-based phase change energy storage material.

[0068] Example 4

[0069] Precision casting shelling waste-based phase change energy storage material, including the following raw materials by weight: 53kg of 200-mesh precision casting shelling waste, 35kg of 200-mesh fly ash, 20kg of paraffin, 6kg of water, and 6kg of polyvinyl alcohol aqueous solution with a mass concentration of 8%;

[0070] The method for preparing the above-mentioned precision casting shelling waste-based phase change energy storage material specifically comprises the following steps:

[0071] (1) First, the precision casting shelling waste and fly ash were placed in a 30°C constant temperature drying oven and dried for 4 hours, and then dry-mixed with a paraffin roller sand mixer for 3 minutes to obtain a base material;

[0072] (2) adding water and polyvinyl alcohol aqueous solution to the substrate, wet mixing for 3 minutes, adding the substrate and 20 zirconium oxide balls with a diameter of 5 mm to a drum ball mill, and ball milling at a speed of 800 r / min for 8 minutes to obtain a mixed material;

[0073] (3) The mixed material is loaded into a mold, added to a press, and pressed using a Φ50 mm pressure head at a pressure of 60 MPa for 30 seconds and a compaction strength of 0.4 MPa to obtain a pressurized material;

[0074] (4) placing the pressurized material in a drying oven at 250° C. and drying for 4 h to obtain a dry material;

[0075] (5) The dried material is placed in a box-type resistance furnace, heated to 1000°C at a heating rate of 10°C / min, and sintered for 8 hours to obtain a precision casting shelling waste-based phase change energy storage material.

[0076] Performance Testing

[0077] 1. The actual pictures of the dried materials obtained in step (4) of Examples 1-4 are as follows: Figure 1-4 shown.

[0078] Depend on Figure 1-4 It can be seen that the green body samples of the dried materials in Examples 1-4 have good appearance quality, no obvious surface cracks are observed, and the fly ash particles achieve good mechanical bonding with the precision casting shelling waste particles under the viscous bonding effect of the binder.

[0079] 2. Take the precision casting shelling waste-based phase change energy storage materials prepared in Examples 1-4, and test their performances at 800°C.

[0080] The results are shown in Table 1.

[0081] Table 1 Performance test results of phase change energy storage materials based on precision casting shelling waste in Examples 1-4

[0082] Test items Test Results Bulk density <![CDATA[≥2.0g / cm 3 ]]> Thermal conductivity ≥0.3w / m·k Specific heat ≥0.85kJ / kg.℃ Phase transition temperature 50-800℃ Latent heat coefficient of phase change 70-90J / g Compressive strength ≥30MPa Flexural strength ≥13MPa Linear expansion rate ≤2.7％

[0083] It can be seen from Table 1 that at 800°C, the volume density of the phase change energy storage material based on precision casting shelling waste in Example 1-4 is ≥2.0 g / cm 3 , thermal conductivity ≥0.3w / m·k, specific heat capacity ≥0.85kJ / kg·℃, phase change temperature is 50-800℃, phase change latent heat coefficient is 70-90J / g, compressive strength ≥30MPa, flexural strength ≥13MPa, linear expansion rate ≤2.7%.

[0084] The above experiments show that the precision casting shelling waste-based phase change energy storage material of the present invention has high compressive strength, flexural strength, specific heat capacity and phase change latent heat, as well as good thermal conductivity, and has the excellent characteristic of low density.

[0085] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A precision casting shelling waste-based phase change energy storage material, characterized in that: The invention comprises the following raw materials in parts by weight: 50-75 parts of precision casting shelling waste, 5-40 parts of fly ash, 4-20 parts of phase change agent, 3-6 parts of water and 6-16 parts of binder.

2. The precision casting shelling waste-based phase change energy storage material according to claim 1, characterized in that: The invention comprises the following raw materials in parts by weight: 73 parts of precision casting shelling waste, 8 parts of fly ash, 4 parts of phase change agent, 3 parts of water and 16 parts of binder.

3. The precision casting shelling waste-based phase change energy storage material according to claim 1, characterized in that: The invention comprises the following raw materials in parts by weight: 67 parts of precision casting shelling waste, 17 parts of fly ash, 10 parts of phase change agent, 4 parts of water and 12 parts of binder.

4. The precision casting shelling waste-based phase change energy storage material according to claim 1, characterized in that: The invention comprises the following raw materials in parts by weight: 60 parts of precision casting shelling waste, 26 parts of fly ash, 15 parts of phase change agent, 5 parts of water and 9 parts of binder.

5. The precision casting shelling waste-based phase change energy storage material according to claim 1, characterized in that: The invention comprises the following raw materials in parts by weight: 53 parts of precision casting shelling waste, 35 parts of fly ash, 20 parts of phase change agent, 6 parts of water and 6 parts of binder.

6. A precision casting shelling waste-based phase change energy storage material according to any one of claims 1 to 5, characterized in that: The particle sizes of the precision casting shelling waste and fly ash are both 20-200 meshes.

7. A precision casting shelling waste-based phase change energy storage material according to any one of claims 1 to 5, characterized in that: The phase change agent is at least one of paraffin, polyol, water and inorganic salt.

8. The precision casting shelling waste-based phase change energy storage material according to claim 7, characterized in that: The binder is at least one of polyvinyl alcohol aqueous solution, water glass and phenolic resin; The mass concentration of the polyvinyl alcohol aqueous solution is 8%; the mass ratio of the polyvinyl alcohol aqueous solution to water glass is 1:2; the mass ratio of the polyvinyl alcohol aqueous solution to phenolic resin is 1:1; the mass ratio of water glass to phenolic resin is 1:1; the mass ratio of the polyvinyl alcohol aqueous solution, water glass and phenolic resin is 1:1:

1.

9. A method for preparing a phase change energy storage material based on precision casting shelling waste, characterized in that: The specific steps include: (1) firstly drying the precision casting shelling waste and fly ash, and then adding a phase change agent for dry mixing to obtain a base material; (2) adding water and a binder to the base material, wet mixing, and ball milling to obtain a mixed material; (3) pressurizing the mixed material to obtain a pressurized material; (4) drying the pressurized material to obtain a dried material; (5) Sintering the dried material to obtain the precision casting shelling waste-based phase change energy storage material.

10. The method for preparing a precision casting shelling waste-based phase change energy storage material according to claim 9, characterized in that: In step (1), the drying equipment is a constant temperature drying oven, the temperature is 30°C, and the time is 2-4 hours; the dry mixing equipment is a grinding wheel sand mixer, and the time is 3 minutes; In step (2), the wet mixing time is 3-5 min; the ball milling equipment is a drum ball mill, the speed is 800 r / min, and the time is 8 min; In step (3), the pressurizing and molding equipment is a press machine, the pressure is 60MPa, the time is 30s, and the compaction strength is 0.1-0.4MPa; In step (4), the drying equipment is a drying oven, the temperature is 180-250° C., and the time is 2-4 hours; In step (5), the sintering equipment is a box-type resistance furnace, the heating rate is 5-10°C / min, the temperature is 800-1000°C, and the time is 5-8h.

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