CN115180922B

CN115180922B - Sintered water permeable brick based on granite waste and coal cinder and preparation method thereof

Info

Publication number: CN115180922B
Application number: CN202210762007.1A
Authority: CN
Inventors: 包申旭; 桂娅琼; 黄敏; 张一敏; 黄修林
Original assignee: Wuhan University of Technology WUT
Current assignee: Wuhan University of Technology WUT
Priority date: 2022-06-30
Filing date: 2022-06-30
Publication date: 2023-08-01
Anticipated expiration: 2042-06-30
Also published as: CN115180922A

Abstract

The invention discloses a sintered water permeable brick based on granite waste and coal cinder and a preparation method thereof. The preparation method of the sintered water permeable brick based on granite waste and coal cinder comprises the following steps: and uniformly mixing granite waste, coal cinder, binder and water, and then forming, drying and sintering to obtain the sintered water permeable brick. According to the characteristics of granite waste and coal cinder, the method for preparing the water permeable brick by adopting the partial aggregate sintering method does not need to add artificial aggregate and high-temperature binder in the preparation process, has the advantages of few raw material types, simple preparation process, low cost and high production controllability, and simultaneously saves energy sources; the flexural strength and the water permeability coefficient of the water permeable brick prepared by the invention reach the national standard; meanwhile, the permeable bricks are prepared from the granite waste and the coal cinder, so that the environmental problem caused by stacking of the granite waste and the coal cinder is relieved, the land resource waste caused by solid waste stacking is solved, and the sustainable development of the stone industry is promoted.

Description

Sintered water permeable brick based on granite waste and coal cinder and preparation method thereof

Technical Field

The invention relates to the technical field of building materials, in particular to a sintered water permeable brick based on granite waste and coal cinder and a preparation method thereof.

Background

Coal cinder is waste produced by burning coal. How to recycle the coal slag becomes a serious difficulty in the research of the current solid waste recycling field. The granite has the advantages of fine structure, higher compressive strength, good chemical stability, difficult efflorescence, strong durability, capability of carrying out various special-shaped processing and good plate splicing property, and is an important building material. But the pollution problem caused by granite industry to the environment is not ignored. During the process of mining and processing granite, a large amount of leftover materials, powder particles and the like are generated. A large amount of stone waste residues are stacked at will, so that a large amount of land is occupied, soil vegetation is destroyed, and serious water and soil loss and soil degradation phenomena are generated. Saw mud generated in the granite processing process often flows into streams or rivers along surface runoffs when raining, and serious damage is caused to water quality; the saw mud is piled for a long time, and can be converted into air dust after being dried and weathered to cause air pollution. These have a great impact on the living and ecological environment of the residents around the mine.

In recent years, along with the rapid development of economy and the continuous acceleration of urban development, natural vegetation and bare soil are continuously replaced by various buildings and waterproof hardened pavements, and the hydrologic processes such as precipitation, evaporation, runoff and the like and the heat exchange process are affected. Therefore, the problems of urban heat island effect, rain island effect, urban sea watching and the like can be caused, and inconvenience is brought to urban construction and life of people. The water permeable brick is a pavement water permeable material with certain water permeability and water retention, not only can effectively permeate rainwater and lighten urban drainage pressure, but also can support water sources, and simultaneously evaporates the water in the brick body when the weather is hot so as to achieve the effect of relieving urban living heat environment. The water permeable brick material plays an irreplaceable role in relieving urban heat island effect, relieving urban drainage pressure and the like by virtue of good water permeability, water storage and water retention capacity and wear-resisting and skid-resisting properties. The water permeable brick is prepared by utilizing industrial solid waste, so that the construction of sponge cities can be supported, the environmental risk of solid waste landfill can be relieved, and win-win effect on economic and environmental benefits is achieved.

Chinese patent 201810745515.2 discloses a water permeable brick prepared from granite stone waste and a preparation method thereof, wherein the water permeable brick is prepared from granite stone particles, high bauxite aggregate particles, granite stone sawing mud, plastic clay, high bauxite fine powder and auxiliary binders. The method has the advantages of various raw materials, strict requirements on different raw material grain grades and proportions, addition of plastic clay as a high-temperature binder in the preparation process, and difficult control of the production process. Among them, plastic clay is a non-renewable resource, and in order to protect natural clay brick resources, environment-friendly building materials are developed, and some countries such as china begin to prohibit the production and use of clay bricks. Chinese patent 201811649878.2 discloses a water permeable cinder block, which is prepared from cement, cinder particles, active carbon, polyacrylamide, acrylic acid polymer, polyoxyethylene shrinkage reducing agent, sodium abietate and early strength agent. The method has the problems of various raw materials, long curing period (34 days are needed), low production efficiency, occupation of a large amount of sites and unfavorable popularization and application of the permeable cinder bricks.

Disclosure of Invention

The invention aims to overcome the technical defects, and provides a sintered water permeable brick based on granite waste and coal cinder and a preparation method thereof, which solve the technical problems of various raw materials, complex preparation process, high cost and low production controllability of the water permeable brick in the prior art.

The first aspect of the invention provides a method for preparing a sintered water permeable brick based on granite waste and coal cinder, comprising the following steps:

and uniformly mixing granite waste, coal cinder, binder and water, and then forming, drying and sintering to obtain the sintered water permeable brick.

According to a second aspect of the invention, a sintered water permeable brick based on granite waste and coal cinder is provided, and the sintered water permeable brick based on granite waste and coal cinder is obtained by the preparation method of the sintered water permeable brick based on granite waste and coal cinder provided in the first aspect of the invention.

Compared with the prior art, the invention has the beneficial effects that:

according to the characteristics of granite waste and coal cinder, the method for preparing the water permeable brick by adopting the partial aggregate sintering method does not need to add artificial aggregate and high-temperature binder in the preparation process, has the advantages of few raw material types, simple preparation process, low cost and high production controllability, and simultaneously saves energy sources; the flexural strength and the water permeability coefficient of the water permeable brick prepared by the invention reach the national standard; meanwhile, the permeable bricks are prepared from the granite waste and the coal cinder, so that the environmental problem caused by stacking of the granite waste and the coal cinder is relieved, the land resource waste caused by solid waste stacking is solved, and the sustainable development of the stone industry is promoted.

Drawings

Fig. 1 shows a mass ratio of 2 for the individual coal cinder, the individual granite waste: 8 DSC profile of a mixture of coal slag + granite waste.

Detailed Description

The present invention will be described in further detail with reference to the drawings and examples, in order to make the objects, technical solutions and advantages of the present invention more apparent. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.

Referring to fig. 1, fig. 1 shows that the mass ratio of the individual coal cinder, the individual granite waste is 2:8 DSC profile of a mixture of coal slag + granite waste. The coal cinder and granite have obvious exothermic peaks at about 1012 ℃ and 1052 ℃ respectively, the DSC curve is reduced, the exothermic is reduced, and the crystallization melting is presumed; the mixture of the two materials has no obvious exothermic peak in DSC curve after 700 ℃, and the curve starts to drop greatly after 900 ℃. That is, the mixture of the coal cinder and the granite has lower crystallization melting temperature than that of the two raw materials, the liquid phase generated by melting is beneficial to the improvement of the brick strength, and the reduction of the melting temperature can reduce the energy consumption in the process of sintering the water permeable bricks. The invention selects coal cinder and granite as raw materials, and adopts a partial aggregate sintering method to prepare the water permeable brick. The coal cinder contains a large amount of glass bodies and Al ₂ O ₃ Higher content of K ₂ O，Na ₂ The O content is lower, and the hardness and the melting point are higher, so that the coal cinder is not easy to sinter. After the granite waste is added, the granite waste can form a low-temperature eutectic with coal cinder and other raw materials, and the sintering temperature is reduced. Meanwhile, granite can be used as a brick body as coarse aggregate is piled to form gapsIs a water permeable structure of (a). The two raw materials complement each other, and the manufactured water permeable brick can achieve better water permeability and mechanical strength without adding high-temperature binder and artificial aggregate. And the coal cinder contains a large amount of residual carbon, and in the sintering process, the combustion of the residual carbon can generate heat, so that the fuel required in the process of sintering the water permeable bricks can be saved to a certain extent. And certain gas can be discharged in the combustion process to leave holes, so that the water permeability of the water permeable brick is improved. The invention prepares the water permeable brick by taking granite waste and coal cinder as raw materials, not only consumes a large amount of solid waste, changes waste into valuable, realizes low-cost preparation of the water permeable brick, has the characteristics of stable ecology, energy conservation and environmental protection and resource circulation, but also solves the problems of land resource waste and environmental pollution caused by solid waste accumulation.

In the invention, the mass ratio of granite waste to coal cinder is (1-9): 1, preferably (1-1.5): 1 or (3-5): 1, more preferably 1:1 or 4:1. In the mass ratio range, the prepared sintered water permeable brick has optimal comprehensive performance.

In the invention, the coal cinder is the residue after coal combustion. In some embodiments of the invention, the mass percentages of the components in the coal cinder are: siO (SiO) ₂ 35-65％、Al ₂ O ₃ 20-50％、 Na ₂ O 0.1-1％、Fe ₂ O ₃ 1-8％、CaO 0.5-3％、K ₂ O 0.1-2％、MgO 0.01-2％、TiO ₂ 0.1-2%; the grain size of the coal cinder is below 0.074 mm.

In the invention, the granite waste is particles obtained by crushing and sieving waste granite stone scraps. In some embodiments of the present invention, the granite particles comprise the following components in percentage by mass: siO (SiO) ₂ 55-85％、Al ₂ O ₃ 5-20％、Na ₂ O 2-8％、Fe ₂ O ₃ 0.5-3％、 CaO 0.5-3％、K ₂ O 1-8％、MgO 0.01-1％、TiO ₂ 0.1-1%; the granite particles have a particle size of 0.6 to 4.75mm, preferably 0.6 to 1.25mm, more preferably 0.9 to 1.25mm.

In the present invention, the binder is polyvinyl alcohol.

In the invention, the mass of the binder is 0.1-1% of the total mass of granite waste and coal cinder, and further 0.3-0.4%.

In the invention, the mass of water is 5-10% of the total mass of granite waste and coal cinder, and further 5-7%.

In some embodiments of the present invention, the process of uniformly mixing granite waste, coal cinder, binder and water is: evenly mixing granite and coal cinder, then adding a mixed solution formed by a binder and water, and continuously evenly mixing.

In the invention, the molding mode is as follows: and (3) injecting a mixture of granite waste, coal cinder, binder and water into a mold, and demolding after compression molding. Further, the molding pressure is 10-30MPa, and the dwell time is 10-60s.

In the invention, the drying temperature is 60-120 ℃, and further 105 ℃; the drying time is 6-12h, and the drying time is 10h.

In the invention, the sintering process is as follows: firstly, raising the temperature from room temperature to a first target temperature at a heating rate of 4-6 ℃/min, then raising the temperature from the first target temperature to a second target temperature at a heating rate of 2-5 ℃/min, and cooling to the room temperature along with a furnace after heat preservation. In the invention, the overflow of the gas product before sintering can be ensured by reducing the temperature rising rate of the second stage.

Further, the first target temperature is 700-760 ℃, preferably 750 ℃; the second target temperature is 1100-1250 ℃, preferably 1125-1175 ℃, more preferably 1150-1175 ℃; the incubation time is 0.5 to 1.5 hours, preferably 0.8 to 1.2 hours, more preferably 1 hour.

Example 1

(1) Crushing granite waste, sieving to obtain particles with the particle size of 0.9-1.25mm and coal cinder particle size below 0.074 mm.

(2) Mixing granite and coal cinder uniformly according to the mass ratio of 90 parts to 10 parts, adding a polyvinyl alcohol solution with the weight ratio of 6% (the mass fraction of the solution is 6%), injecting the mixture into a mould after uniformly mixing, pressurizing to 10MPa, maintaining the pressure for 30s, demoulding, and drying at 105 ℃ for 10h to remove water, thus obtaining the water permeable brick green brick.

(3) The green embryo is put into a muffle furnace for roasting, and is firstly heated to 750 ℃ from room temperature at a heating rate of 5 ℃/min, and then heated to 1150 ℃ from 750 ℃ at a heating rate of 4 ℃/min; finally, the mixture is kept at 1150 ℃ for 1h and then cooled to room temperature along with the furnace.

Example 2

The only difference from example 1 is that the raw materials are added in different amounts during the preparation of the sintered water permeable brick, specifically as follows:

(2) Mixing granite and coal cinder uniformly according to the mass ratio of 80 parts to 20 parts, adding a polyvinyl alcohol solution with the weight ratio of 6% (the mass fraction of the solution is 6%), injecting the mixture into a mould after uniformly mixing, pressurizing to 10MPa, maintaining the pressure for 30s, demoulding, and drying at 105 ℃ for 10h to remove water, thus obtaining the water permeable brick green brick.

Example 3

(2) Mixing granite and coal cinder uniformly according to the mass ratio of 70 parts to 30 parts, adding a polyvinyl alcohol solution with the weight ratio of 6% (the mass fraction of the solution is 6%), injecting the mixture into a mould after uniformly mixing, pressurizing to 10MPa, maintaining the pressure for 30s, demoulding, and drying at 105 ℃ for 10h to remove water, thus obtaining the water permeable brick green brick.

Example 4

(2) Mixing granite and coal cinder uniformly according to the mass ratio of 60 parts to 40 parts, adding a polyvinyl alcohol solution with the weight ratio of 6% (the mass fraction of the solution is 6%), injecting the mixture into a mould after uniformly mixing, pressurizing under 10MPa, maintaining the pressure for 30s, demoulding, and drying at 105 ℃ for 10h to remove water, thus obtaining the water permeable brick green body.

Example 5

(2) Mixing granite and coal cinder uniformly according to the mass ratio of 50 parts to 50 parts, adding a polyvinyl alcohol solution with the weight ratio of 6% (the mass fraction of the solution is 6%), injecting the mixture into a mould after uniformly mixing, pressurizing at 10MPa, maintaining the pressure for 30s, demoulding, and drying at 105 ℃ for 10h to remove water, thus obtaining the water permeable brick green brick.

The sintered water permeable bricks prepared in the above examples 1 to 5 were subjected to performance test, and the results are shown in Table 1.

Table 1 proportioning test (granite particle size 0.9-1.25mm,1150 ℃ C.)

Granite: coal cinder	Permeability coefficient (×10) ^-2 cm/s)	Bending resistance (MPa)	Apparent porosity (%)
				90:10	2.04	2.52	17.21
80:20	2.57	3.33	18.16
				70:30	1.97	2.17	16.82
60:40	2.66	2.96	19.60
				50:50	2.93	3.02	21.56
National standard	≥1.0	≥3.0	/

As can be seen from Table 1, when the ratio of granite to coal cinder is 8:2 and (1.5-1): 1, the prepared water permeable brick has optimal comprehensive performance.

Example 6

(1) Crushing granite waste, sieving to obtain particles with the particle size of 0.6-0.9mm and coal cinder particle size below 0.074 mm.

Example 7

Compared with example 6, the difference is only that during the process of preparing the sintered water permeable brick, the particle size of granite particles is different, specifically as follows:

Example 8

(1) Crushing granite waste, sieving to obtain particles with particle size of 1.25-2mm, and burning cinder particle size below 0.074 mm.

Example 9

(1) Crushing granite waste, sieving to obtain particles with the particle size of 2-2.5mm and coal cinder particle size below 0.074 mm.

Example 10

(1) Crushing granite waste, sieving to obtain particles with the particle size of 2.5-4.75mm and the particle size of coal cinder below 0.074 mm.

The performance test was performed on the above examples 6 to 10, and the results are shown in Table 2.

TABLE 2 particle size test (80:20, 1150 ℃ C.)

Granite particle size (mm)	Permeability coefficient (×10) ^-2 cm/s)	Bending resistance (MPa)	Apparent porosity (%)
				0.6-0.9	2.79	4.25	18.41
0.9-1.25	3.37	3.01	17.28
				1.25-2	3.63	2.89	17.12
2-2.5	4.03	2.09	16.79
				2.5-4.75	4.43	1.60	15.41
National standard	≥1.0	≥3.0	/

As can be seen from Table 2, when the granite particle size is 0.6-1.25, the prepared water permeable brick has optimal comprehensive performance and meets the national standard.

Example 11

(3) The green embryo is put into a muffle furnace for roasting, and is firstly heated to 750 ℃ from room temperature at a heating rate of 5 ℃/min, and then heated to 1100 ℃ from 750 ℃ at a heating rate of 4 ℃/min; finally, the temperature is kept at 1100 ℃ for 1h, and then the mixture is cooled to room temperature along with the furnace.

Example 12

The only difference compared with example 11 is that the sintering temperature is different in the process of preparing the sintered water permeable brick, and the specific steps are as follows:

(3) The green embryo is put into a muffle furnace for roasting, and is firstly heated to 750 ℃ from room temperature at a heating rate of 5 ℃/min, and then heated to 1125 ℃ from 750 ℃ at a heating rate of 4 ℃/min; finally, the mixture is kept at 1125 ℃ for 1 hour and then cooled to room temperature along with the furnace.

Example 13

(3) The green embryo is put into a muffle furnace for roasting, and is firstly heated to 750 ℃ from room temperature at a heating rate of 5 ℃/min, and then heated to 1150 ℃ from 750 ℃ at a heating rate of 4 ℃/min; finally, the temperature is kept at 1150 ℃ for 1h, and then the mixture is cooled to room temperature along with the furnace.

Example 14

(3) The green embryo is put into a muffle furnace for roasting, and is firstly heated to 750 ℃ from room temperature at a heating rate of 5 ℃/min, and then heated to 1175 ℃ from 750 ℃ at a heating rate of 4 ℃/min; finally, the mixture is kept at 1175 ℃ for 1 hour and then cooled to room temperature along with the furnace.

Example 15

(3) The green embryo is put into a muffle furnace for roasting, and is firstly heated to 750 ℃ from room temperature at a heating rate of 5 ℃/min, and then heated to 1200 ℃ from 750 ℃ at a heating rate of 4 ℃/min; finally, the temperature is kept at 1200 ℃ for 1h, and then the mixture is cooled to room temperature along with the furnace.

Example 16

(3) The green embryo is put into a muffle furnace for roasting, and is firstly heated to 750 ℃ from room temperature at a heating rate of 5 ℃/min, and then heated to 1225 ℃ from 750 ℃ at a heating rate of 4 ℃/min; finally, the mixture is kept at 1225 ℃ for 1 hour and then cooled to room temperature along with the furnace.

Example 17

(3) The green embryo is put into a muffle furnace for roasting, and is firstly heated to 750 ℃ from room temperature at a heating rate of 5 ℃/min, and then heated to 1250 ℃ from 750 ℃ at a heating rate of 4 ℃/min; finally, after incubation for 1h at 1250 ℃, cooling to room temperature with the furnace.

The sintered water permeable bricks prepared in the above examples 11 to 17 were subjected to performance test, and the results are shown in Table 3.

TABLE 3 temperature test (granite particle size 0.9-1.25mm, 80:20)

Temperature (. Degree. C.)	Permeability coefficient (×10) ^-2 cm/s)	Bending resistance (MPa)	Apparent porosity (%)
				1100	4.02	0.60	25.21
1125	3.94	1.19	22.61
				1150	3.42	3.07	17.70
1175	2.88	4.14	11.53
				1200	0.64	6.04	4.69
1225	0.23	5.93	2.11
				1250	0.00	3.72	1.86
National standard	≥1.0	≥3.0	/

Note that: in order to better compare the performances of the same batch of water permeable bricks, the test conditions of examples 2, 7 and 13 are identical, and the results are within the allowable error range of the test and do not affect the change rule although the results have certain deviation.

As can be seen from Table 3, the prepared water permeable bricks can meet the national standard when the sintering temperature is 1150-1175 ℃.

Example 18

Compared with example 14, the difference is only that the raw materials are added in different amounts in the process of preparing the sintered water permeable brick, and the raw materials are specifically as follows:

(2) Uniformly mixing granite and coal cinder according to the mass ratio of 40 parts to 60 parts, adding a polyvinyl alcohol solution with the weight ratio of 6% (the mass fraction of the solution is 6%), uniformly mixing, then injecting into a mould, pressurizing under 10MPa, maintaining the pressure for 30s, demoulding, and then baking at 105 ℃ for 10h to remove water, thus obtaining the water permeable brick green body.

Example 19

The only difference compared with example 14 is that during the process of preparing the sintered water permeable brick, the granite particles have different particle sizes, specifically as follows:

(1) Crushing granite waste, sieving to obtain particles with the particle size of 4.75-7mm, and the particle size of coal cinder is below 0.074 mm.

Example 20

crushing granite waste, sieving to obtain particles with the particle size of 0.034-0.6mm and coal cinder particle size below 0.074 mm.

The baking-free water permeable bricks prepared in examples 18 to 20 were subjected to performance test, and the results are shown in Table 4.

TABLE 4 Table 4

From the results of Table 4, it can be seen that even at optimal temperature conditions, the mass ratio of granite to cinder should not be too low, and the water permeability coefficient will be significantly reduced once the mass ratio of granite to cinder is less than 1:1. Meanwhile, even under the optimal temperature condition, the particle size of the granite cannot be too high or too low, the water permeability coefficient is obviously reduced, and the flexural strength is obviously reduced due to the too high particle size. The water permeable brick meeting the national standard is successfully prepared by optimizing the mass ratio of granite to coal cinder, the particle size of the granite and the sintering temperature.

The above-described embodiments of the present invention do not limit the scope of the present invention. Any other corresponding changes and modifications made in accordance with the technical idea of the present invention shall be included in the scope of the claims of the present invention.

Claims

1. The preparation method of the sintered water permeable brick based on granite waste and coal cinder is characterized by comprising the following steps:

uniformly mixing granite waste, coal cinder, binder and water, and then forming, drying and sintering to obtain a sintered water permeable brick; wherein the mass ratio of the granite waste to the coal cinder is (1-9): 1, a step of; the sintering process comprises the following steps: firstly, raising the temperature from room temperature to a first target temperature at a heating rate of 4-6 ℃/min, then raising the temperature from the first target temperature to a second target temperature at a heating rate of 2-5 ℃/min, and cooling to the room temperature along with a furnace after heat preservation; the first target temperature is 700-760 ℃, the second target temperature is 1100-1250 ℃, and the heat preservation time is 0.5-1.5 h.

2. The method for preparing the sintered water permeable brick based on granite waste and coal cinder according to claim 1, wherein the mass ratio of the granite waste to the coal cinder is (1-1.5): 1 or (3-5): 1.

3. The method for preparing the sintered water permeable brick based on granite waste and coal cinder according to claim 1, wherein the particle size of the coal cinder is below 0.074 and mm; the particle size of the granite waste is 0.6-4.75 and mm.

4. The method for preparing a sintered water permeable brick based on granite waste and coal cinder as set forth in claim 1, wherein the particle size of the granite waste is 0.6-1.25-mm.

5. The method for preparing a sintered water permeable brick based on granite waste and coal cinder as set forth in claim 1, wherein the binder is polyvinyl alcohol.

6. The method for preparing the sintered water permeable brick based on granite waste and coal cinder according to claim 1, wherein the mass of the binder is 0.1% -1% of the total mass of the granite waste and the coal cinder; the mass of the water is 5% -10% of the total mass of granite waste and coal cinder.

7. The method for preparing the sintered water permeable brick based on granite waste and coal cinder according to claim 1, wherein the first target temperature is 750 ℃, the second target temperature is 1150-1175 ℃, and the heat preservation time is 1h.

8. A sintered water permeable brick based on granite waste and coal cinder, wherein the sintered water permeable brick based on granite waste and coal cinder is obtained by the preparation method of the sintered water permeable brick based on granite waste and coal cinder as set forth in any one of claims 1 to 7.