阅读说明：本技术 一种煤矸石相变集料及其制备方法 (Coal gangue phase change aggregate and preparation method thereof ) 是由 高育欣 祝小靓 郭照恒 王军 杨文� 赖航 宋文静 程宝军 麻鹏飞 于 2021-01-07 设计创作，主要内容包括：本发明公开了一种煤矸石相变集料及其制备方法,所述制备方法包括以下步骤：S1：以煤矸石为原料,预先进行破碎,将破碎后的煤矸石在600-800℃条件下煅烧2-4h；S2：待煅烧后的产物冷却后取其50-65％并与30-40％的石蜡进行混合,将混合物在负压环境下,先在T-1温度条件下密封保温3-5h,然后降温至T-2温度条件下继续密封保温3-5h；S3：保温结束后,将步骤S2得到的产物取出冷却、破碎,然后与5-10％的活性掺合料在T-3温度条件下进行混合,使所述活性掺合料包裹在煤矸石-石蜡复合颗粒的表面,得到所述煤矸石相变集料。本发明工艺简单,利用固体废弃物煤矸石,成本较低,绿色环保,具有较好的控温效果,可以良好的适用于大体积混凝土。(The invention discloses a coal gangue phase-change aggregate and a preparation method thereof, wherein the preparation method comprises the following steps: s1: taking coal gangue as a raw material, crushing in advance, and calcining the crushed coal gangue at the temperature of 600-; s2: cooling the calcined product, mixing 50-65% with 30-40% paraffin, and mixing under negative pressure 1 Sealing and insulating for 3-5h at temperature, and cooling to T 2 Continuously sealing and preserving heat for 3-5h under the temperature condition; s3: after the heat preservation is finished, taking out the product obtained in the step S2, cooling, crushing, and then mixing with 5-10% of active admixture in T 3 And mixing under the temperature condition to enable the active admixture to wrap the surfaces of the coal gangue-paraffin wax composite particles to obtain the coal gangue phase change aggregate. The invention has simple process, utilizes solid waste coal gangue, has lower cost, is green and environment-friendly, has better temperature control effect, and can be well suitable for mass concrete.)

1. The coal gangue phase change aggregate is characterized by comprising the following components in percentage by mass: 50-65% of coal gangue, 30-40% of paraffin and 5-10% of active admixture.

2. The coal gangue phase change aggregate as claimed in claim 1, wherein the active admixture is one or more of mineral powder, gasified slag, steel slag, manganese slag, silica fume and fly ash.

3. The preparation method of the coal gangue phase-change aggregate is characterized by comprising the following steps:

s1: taking coal gangue as a raw material, crushing in advance, and calcining the crushed coal gangue at the temperature of 600-;

s2: cooling the calcined product, mixing 50-65% with 30-40% paraffin, and mixing under negative pressure₁Sealing and insulating for 3-5h at temperature, and cooling to T₂Continuously sealing and preserving heat for 3-5h under the temperature condition;

s3: after the heat preservation is finished, taking out the product obtained in the step S2, cooling, crushing, and then mixing with 5-10% of active admixture in T₃And mixing under the temperature condition to enable the active admixture to wrap the surfaces of the coal gangue-paraffin wax composite particles to obtain the coal gangue phase change aggregate.

4. The preparation method of the coal gangue phase-change aggregate as claimed in claim 3, wherein in the step S1, the particle size of the crushed coal gangue is less than or equal to 5 mm.

5. The preparation method of the coal gangue phase-change aggregate as claimed in claim 3, wherein in the step S2, the pressure value of the negative pressure environment is less than or equal to-1 MPa.

6. The preparation method of the coal gangue phase-change aggregate as claimed in claim 3, wherein in the step S2, T is₁The temperature is 1.5-3.0 times of the temperature corresponding to the highest point of the main peak of the phase change heat absorption of the paraffin.

7. The preparation method of the coal gangue phase-change aggregate as claimed in claim 3, wherein in the step S2, T is₂The temperature is the temperature corresponding to the highest point of the main peak of the paraffin phase-change heat absorption.

8. The preparation method of the coal gangue phase-change aggregate as defined in claim 3, wherein in the step S3, the grain size of the crushed product is less than or equal to 5 mm.

9. According to any of claims 3-8The preparation method of the coal gangue phase-change aggregate is characterized in that in the step S3, T₃Temperature less than T₂And (3) temperature.

10. The preparation method of the coal gangue phase-change aggregate as claimed in claim 9, wherein T is T₃The temperature is 0.5-0.9 times of the temperature corresponding to the highest point of the main peak of the phase change heat absorption of the paraffin.

Technical Field

The invention relates to the technical field of building materials, in particular to a coal gangue phase change aggregate and a preparation method thereof.

Background

The heat generated by hydration of the cementing material in the large-volume concrete is not dissipated as fast as the heat on the surface, so that the temperature difference between the inside and the outside is too large, and the generated temperature stress is easy to crack the concrete. The phase-change energy storage building material has the advantages of both common building materials and phase-change materials, can absorb and release a proper amount of heat energy, and can be used with other traditional building materials. The phase-change material realizes the storage of heat energy through the change of the energy storage medium, and when the ambient temperature is higher than a certain value, the phase-change material is melted from a solid state to a liquid state to absorb heat. The application of the phase change material in the mass concrete can reduce the hydration heat when the temperature is too high, and reduce the risk of temperature damage of the mass concrete.

In the current research on coal gangue phase change materials, there is a coal gangue-based medium-high temperature phase change heat storage material prepared by grinding, mixing, press forming and sintering coal gangue as a framework material (a coal gangue-based medium-high temperature phase change heat storage material and a preparation method thereof) under the patent number of CN 108624294a, but the coal gangue is used in a small amount, and is used in the fields of solar power generation, waste heat recovery and the like, and the consumption of a large amount of industrial solid waste coal gangue is low.

Disclosure of Invention

Aiming at the problems, the invention aims to provide a coal gangue phase-change aggregate and a preparation method thereof.

The technical scheme of the invention is as follows:

on the one hand, the coal gangue phase change aggregate comprises the following components in percentage by mass: 50-65% of coal gangue, 30-40% of paraffin and 5-10% of active admixture.

Preferably, the active admixture is one or more of mineral powder, gasified slag, steel slag, manganese slag, silica fume and fly ash.

On the other hand, the preparation method of the coal gangue phase-change aggregate comprises the following steps:

s1: taking coal gangue as a raw material, crushing in advance, and calcining the crushed coal gangue at the temperature of 600-;

s2: cooling the calcined product, mixing 50-65% with 30-40% paraffin, and mixing under negative pressure₁Sealing and insulating for 3-5h at temperature, and cooling to T₂Continuously sealing and preserving heat for 3-5h under the temperature condition;

s3: after the heat preservation is finished, taking out the product obtained in the step S2, cooling, crushing, and then mixing with 5-10% of active admixture in T₃And mixing under the temperature condition to enable the active admixture to wrap the surfaces of the coal gangue-paraffin wax composite particles to obtain the coal gangue phase change aggregate.

Preferably, in step S1, the coal refuse after crushing has a particle size of 5mm or less.

Preferably, in step S2, the pressure value of the negative pressure environment is equal to or less than-1 MPa.

Preferably, in step S2, T₁The temperature is 1.5-3.0 times of the temperature corresponding to the highest point of the main peak of the phase change heat absorption of the paraffin.

Preferably, in step S2, T₂The temperature is the temperature corresponding to the highest point of the main peak of the paraffin phase-change heat absorption.

Preferably, in step S3, the particle size of the crushed product is 5mm or less.

Preferably, in step S3, T₃Temperature less than T₂And (3) temperature.

Preferably, T is₃The temperature is 0.5-0.9 times of the temperature corresponding to the highest point of the main peak of the phase change heat absorption of the paraffin.

The invention has the beneficial effects that:

according to the invention, the coal gangue, the paraffin and the active admixture are combined, and the coal gangue phase-change aggregate is prepared by mixing, heating under negative pressure, cooling and other procedures by utilizing the porous structure of the coal gangue and the phase change characteristics of the paraffin; then, the surface of the phase-change aggregate is coated with an active admixture to improve the quality of the interface joint between the phase-change aggregate and a hydrated hydration product, and the phase-change aggregate can be well suitable for mass concrete. The preparation method disclosed by the invention is simple in process, utilizes solid waste coal gangue, is low in cost, is green and environment-friendly, and has a good temperature control effect.

Detailed Description

The present invention will be further described with reference to the following examples.

It should be noted that, in the present application, the embodiments and the technical features of the embodiments may be combined with each other without conflict.

It is noted that, unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

Example 1

A preparation method of coal gangue phase-change aggregate comprises the following steps:

s1: the coal gangue is taken as a raw material, the coal gangue is crushed in advance, and the crushed coal gangue is calcined for 2 hours at the temperature of 600 ℃.

S2: and after calcination, cooling at room temperature, mixing the cooled 60% product with 30% paraffin for 20min, wherein the temperature corresponding to the highest point of the phase change heat absorption main peak of the paraffin is 60 ℃, then placing the mixture in a negative pressure environment of-2 MPa, sealing and preserving heat for 3h at 120 ℃, and then cooling to 60 ℃ and continuing to seal and preserve heat for 5 h.

S3: and after the heat preservation is finished, taking out the product obtained in the step S2, cooling and crushing the product at room temperature, and then mixing the product with 10% of fly ash at 48 ℃ for 20min to wrap the fly ash on the surfaces of the coal gangue-paraffin composite particles to obtain the coal gangue phase-change aggregate.

Example 2

A preparation method of coal gangue phase-change aggregate comprises the following steps:

s1: the coal gangue is taken as a raw material, the coal gangue is crushed in advance, and the crushed coal gangue is calcined for 2 hours at the temperature of 700 ℃.

S2: and after calcination, cooling at room temperature, mixing the cooled 60% product with 30% paraffin for 20min, wherein the temperature corresponding to the highest point of the phase change heat absorption main peak of the paraffin is 54 ℃, then placing the mixture into a negative pressure environment of-2 MPa, sealing and preserving heat at 108 ℃ for 3h, and then cooling to 54 ℃ and continuing to seal and preserve heat for 5 h.

S3: and (4) after the heat preservation is finished, taking out the product obtained in the step S2, cooling and crushing the product at room temperature, and then mixing the product with 10% of silica fume at 43 ℃ for 20min to wrap the silica fume on the surfaces of the coal gangue-paraffin wax composite particles to obtain the coal gangue phase-change aggregate.

Example 3

A preparation method of coal gangue phase-change aggregate comprises the following steps:

s1: the coal gangue is taken as a raw material, the coal gangue is crushed in advance, and the crushed coal gangue is calcined for 2 hours at the temperature of 800 ℃.

S2: and after calcination, cooling at room temperature, mixing the cooled 55% product with 30% paraffin for 20min, wherein the temperature corresponding to the highest point of the phase change heat absorption main peak of the paraffin is 80 ℃, then placing the mixture into a negative pressure environment of-2 MPa, sealing and preserving heat at 160 ℃ for 3h, and then cooling to 80 ℃ and continuing to seal and preserve heat for 4 h.

S3: and (4) after the heat preservation is finished, taking out the product obtained in the step (S2), cooling and crushing the product at room temperature, and then mixing the product with 15% of mineral powder at 64 ℃ for 20min to wrap the mineral powder on the surfaces of the coal gangue-paraffin composite particles to obtain the coal gangue phase-change aggregate.

Test example

The coal gangue phase change aggregate prepared in the example 1-3 is substituted for sand by 30% by volume, the hydration heat of concrete is tested and compared with an unsubstituted sample, and the test results are shown in table 1:

TABLE 1 hydration heat test results (. degree. C.) for the coal gangue phase change material-doped concrete of each example

Time	30min	1h	3h	6h	12h	24h	30h	36h
									Control group	17.2	18.7	20.0	29.5	82.4	63.6	47.4	38.0
Example 1	16.1	17.2	18.4	27.2	62.6	57.3	50.8	36.4
									Example 2	16.8	17.7	19.1	28.2	67.3	59.4	49.7	34.1
Example 3	15.5	16.2	17.6	27.4	57.8	52.2	51.2	37.0

As can be seen from table 1, the hydration exotherm of the concrete can be significantly reduced using embodiments of the present invention.

It should be noted that, in addition to the above examples, the present inventors made other changes to the component usage (for example, end point value, intermediate value), the kind of the active admixture, the calcination temperature, the calcination time, the negative pressure environment, the holding time, and the holding temperature (especially, T) by experimental design methods such as orthogonal experiments₁The temperature is T corresponding to the highest point of the main peak of the phase change heat absorption of the paraffin₂1.5 times, 1.7 times, 2.5 times, 2.8 times, 3.0 times, etc. of temperature T₃The temperature is T corresponding to the highest point of the main peak of the phase change heat absorption of the paraffin₂0.5 times, 0.6 times, 0.7 times, 0.9 times) of the temperature, and the like, the obtained coal gangue phase change aggregate can obviously reduce the hydration heat release of the concrete.

Although the present invention has been described with reference to a preferred embodiment, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.