Preparation method of high-strength coal gangue sintered brick

Abstract

The application relates to a preparation method of high-strength coal gangue sintered bricks, which comprises the following steps: step 1, mixing the powder of coal gangue and quartz sandstone; step 2, adding fluoromanganous into the first mixture and carrying out wet ball milling treatment; step 3, pressing the second mixture into a shape, and then drying in an oven to obtain a precast brick blank; and step 4, placing the precast brick blank in a muffle furnace, carrying out temperature rising sintering treatment, and then cooling to room temperature to obtain the coal gangue sintered brick. The quartz sandstone is added as a mixed filling material on the basis of the coal gangue, and then the fluoromanganous is further added as a modified reinforcing material, so that the strength of the prepared coal gangue sintered brick is greatly improved, and the porosity can reach more than 40%, thereby greatly increasing the heat preservation performance of the sintered brick.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of building materials, and particularly relates to a preparation method of high-strength coal gangue sintered brick. BACKGROUND

[0002] With the development of society, the demand for sintered bricks is increasing, and the conventional sintered bricks usually use clay as raw material, which has caused a large number of sintered bricks produced by clay to artificially destroy a lot of good farmland in the past few years. In order to solve the above problems, people replace clay with coal gangue as raw material to make sintered bricks, which not only reduces the mining of clay, but also turns waste into treasure.

[0003] Coal gangue is a byproduct of coal mining, which has a great impact on the environment and has become one of the four solid wastes in China. At present, the main utilization methods include power generation, building materials, landfill, reclamation, chemical products and new ceramic products. Among them, as building materials, it has been rising since the 70s, with large quantity, simple process, low cost and high added value. The main products are hollow wall bricks, pavement bricks, cement materials, concrete, etc. The addition amount of coal gangue in cement materials is relatively low, about 20%, otherwise it will affect the performance. There are more researches on the preparation of sintered pavement bricks by using coal gangue, but few products are actually produced, mainly because the strength does not meet the index requirements. SUMMARY

[0004] In view of the problems in the prior art, the purpose of the present application is to provide a preparation method of high-strength coal gangue sintered brick.

[0005] The purpose of the present application is achieved by the following technical solutions:

[0006] A preparation method of high-strength coal gangue sintered brick, comprising the following steps:

[0007] Step 1, mix the powders of coal gangue and quartz sandstone, use a crusher for crushing treatment, and obtain a first mixture;

[0008] Step 2, add manganese fluoride to the first mixture, mix with deionized water uniformly, and place in a ball mill for wet ball milling treatment, and obtain a second mixture after the ball milling is completed;

[0009] Step 3, press the second mixture into shape, then dry in an oven, and obtain a precast brick blank;

[0010] Step 4, place the precast brick blank in a muffle furnace, heat and sinter, then cool to room temperature, and obtain a coal gangue sintered brick.

[0011] Preferably, in the step 1, the components of the coal gangue include: the mass percentage of SiO2 is 55.30%-62.52%, the mass percentage of Al2O3 is 17.21%-28.65%, the mass percentage of Fe2O3 is 1.35%-5.42%, the mass percentage of CaO is 1.12%-2.36%, the mass percentage of MgO is 0.53%-1.89%, and the mass percentage of TiO2 is 2.16%-3.57%.

[0012] Preferably, in the step 1, the components of the quartz sandstone include: the mass percentage of SiO2 is 97.28%-97.36%, the mass percentage of Al2O3 is 0.95%-1.03%, and the mass percentage of Fe2O3 is 0.64%-0.68%.

[0013] Preferably, in the step 1, the mass ratio of the coal gangue and the quartz sandstone is 2-5:1-3.

[0014] Preferably, in the step 1, the crushing treatment is to a particle size of 5-10mm.

[0015] Preferably, in the step 2, the particle size of the manganese fluoride (MnF2) is 1-2mm, and the amount of the manganese fluoride added is 15%-35% of the mass of the first mixture.

[0016] Preferably, in the step 2, the total mass of the manganese fluoride and the first mixture to the volume of the deionized water is 1g:(0.8-1.2)mL.

[0017] Preferably, in the step 2, during the ball milling treatment, the grinding balls are zirconium balls with a diameter of 3-5mm, the ball-to-material ratio is 4-6:1, the ball milling speed is 300-400r / min, and the ball milling time is 5-8h.

[0018] Preferably, in the step 3, the pressure for the press forming is 20-30MPa, the temperature for the drying in the oven is 60-80℃, and the drying time is 2-3h.

[0019] Preferably, in the step 4, during the sintering of the preformed brick material, the tail gas is treated by absorption using an alkaline solution (such as a sodium hydroxide solution).

[0020] Preferably, in the step 4, the process of the temperature rising sintering treatment includes two stages: in the first stage, the temperature is raised to 860-920℃ at a speed of 4-6℃ / min, and the holding time is 0.5-1h; in the second stage, the temperature is raised to 1220-1450℃ at a speed of 2-4℃ / min, and the holding time is 1-2h.

[0021] Preferably, the cooling process in step 4 includes two stages: the first stage is to continuously cool to 500℃ after the sintering process at a temperature rising rate of 4-6℃ / min; the second stage is to cool from 500℃ to room temperature, which is not controlled in the cooling rate and can be cooled to room temperature with the furnace.

[0022] The beneficial effects of the present application are:

[0023] 1. The sintered brick prepared from coal gangue on the market not only has low strength but also low porosity, which leads to easy breakage and poor thermal insulation performance. The present application adds quartz sandstone as a mixed filler and fluoromanganous as a modified reinforcing material based on coal gangue, so that the strength of the prepared coal gangue sintered brick is greatly improved, and the porosity can reach more than 40%, greatly increasing the thermal insulation performance of the sintered brick.

[0024] 2. In the present application, fluoromanganous is used as manganese fluoride, which is commonly used as a raw material for kiln industry and non-ferrous metal welding. It is relatively stable at room temperature, but it is easy to oxidize and decompose under high-temperature conditions containing oxygen, generating gas and solid product manganese oxide. The generated gas can maintain the porosity of the sintered brick, and the generated manganese oxide is mainly trimanganese tetraoxide, and part of manganese dioxide and dimanganese trioxide, which can be used as a reinforcing filler to increase the strength of the sintered brick.

[0025] 3. The melting point of fluoromanganous is more than 800 degrees, and it is relatively stable at a lower temperature. Therefore, the present application maintains the melting point temperature of fluoromanganous in the first temperature rising stage of the sintering process, so that fluoromanganous can be fully fused into coal gangue. In the second stage, the decomposition rate is accelerated, and manganese oxide can be more fully generated. DETAILED DESCRIPTION

[0026] The technical solutions of the present application are described below through specific examples. It should be understood that the one or more method steps mentioned in the present application do not exclude other method steps before and after the combination steps or other method steps inserted between the explicitly mentioned steps; it should also be understood that these examples are only used to illustrate the present application and not to limit the scope of the present application. Moreover, unless otherwise stated, the numbering of each method step is only a convenient tool to identify each method step, and is not a limitation on the arrangement order or the scope of the present application that can be implemented. The change or adjustment of the relative relationship is also considered as the scope of the present application that can be implemented without substantial change of the technical content.

[0027] For a better understanding of the above technical solutions, the following describes the exemplary embodiments of the present application in more detail. Although the exemplary embodiments of the present application are shown, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present application and to fully convey the scope of the present application to those skilled in the art.

[0028] The present application is further described below in conjunction with the following examples.

[0029] Example 1

[0030] A method for preparing a high-strength coal gangue sintered brick, comprising the following steps:

[0031] Step 1, mixing powders of coal gangue and quartz sandstone, the components of which are shown in Table 1 and Table 2, the mass ratio of the mixture of coal gangue and quartz sandstone is 3:2, using a crusher for crushing treatment to a particle size of 5-10 mm, to obtain a first mixture;

[0032] Table 1 Mass content component table of coal gangue

[0033]

[0034] Table 2 Mass content component table of quartz sandstone

[0035]

[0036] Step 2, adding manganese fluoride (MnF2) with a particle size of 1-2 mm to the first mixture, the amount of manganese fluoride added is 25% of the mass of the first mixture, and then mixing with deionized water uniformly, the mass-volume ratio of the total mixture and deionized water is 1g:1mL, placing in a ball mill, using zirconium balls with a diameter of 4mm for wet ball milling treatment, the ball-to-material ratio is 5:1, the ball milling speed is 350r / min, the ball milling time is 6h, and after ball milling, a second mixture is obtained;

[0037] Step 3, pressing the second mixture into a mold under a pressure of 25MPa, and then drying in an oven at 70℃ for 2h to obtain a preformed brick blank;

[0038] Step 4, placing the preformed brick blank in a muffle furnace, the first stage is heated to 880℃ at a rate of 5℃ / min, and the holding time is 0.5h; the second stage is heated to 1360℃ at a rate of 3℃ / min, and the holding time is 2h; the tail gas generated during the sintering process is treated by absorption using a 0.5mol / L sodium hydroxide solution, and then cooled to 500℃ at a rate of 5℃ / min, and then cooled to room temperature with the furnace, to obtain a coal gangue sintered brick.

[0039] Example 2

[0040] A method for preparing a high-strength coal gangue sintered brick, comprising the following steps:

[0041] Step 1, mix the powders of coal gangue and quartz sandstone, the components of coal gangue and quartz sandstone are the same as those in Example 1, the mass ratio of the mixture of coal gangue and quartz sandstone is 2:1, use a crusher to crush the mixture to a particle size of 5-10 mm to obtain a first mixture;

[0042] Step 2, add manganese fluoride (MnF2) with a particle size of 1-2 mm to the first mixture, the amount of manganese fluoride added is 15% of the mass of the first mixture, then mix with deionized water uniformly, the mass-volume ratio of the total mixture and deionized water is 1g:0.8mL, place in a ball mill, use zirconium balls with a diameter of 3mm for wet ball milling, the ball-to-material ratio is 4:1, the ball milling speed is 300r / min, the ball milling time is 5h, and the second mixture is obtained after ball milling;

[0043] Step 3, press the second mixture into a mold under a pressure of 20MPa, then place it in an oven at 60℃ for 2-3h to dry, and obtain a preformed brick blank;

[0044] Step 4, place the preformed brick blank in a muffle furnace, the first stage is to heat to 86℃ at a rate of 4℃ / min, and the holding time is 0.5h; the second stage is to heat to 1220℃ at a rate of 2℃ / min, and the holding time is 1h; the tail gas generated during the sintering process is treated by absorption with 0.5mol / L sodium hydroxide solution, then cooled to 500℃ at a rate of 4℃ / min, and then cooled to room temperature with the furnace, to obtain a coal gangue sintered brick.

[0045] Example 3

[0046] A method for preparing a high-strength coal gangue sintered brick, comprising the following steps:

[0047] Step 1, mix the powders of coal gangue and quartz sandstone, the components of coal gangue and quartz sandstone are the same as those in Example 1, the mass ratio of the mixture of coal gangue and quartz sandstone is 5:3, use a crusher to crush the mixture to a particle size of 5-10 mm to obtain a first mixture;

[0048] Step 2, add manganese fluoride (MnF2) with a particle size of 1-2 mm to the first mixture, the amount of manganese fluoride added is 35% of the mass of the first mixture, then mix with deionized water uniformly, the mass-volume ratio of the total mixture and deionized water is 1g:1.2mL, place in a ball mill, use zirconium balls with a diameter of 5mm for wet ball milling, the ball-to-material ratio is 6:1, the ball milling speed is 400r / min, the ball milling time is 8h, and the second mixture is obtained after ball milling;

[0049] Step 3, the second mixture is pressed into a mold under a pressure of 30 MPa, and then dried in an oven at 80℃ for 3h to obtain a preformed brick blank;

[0050] Step 4, the preformed brick blank is placed in a muffle furnace, the first stage is heated to 920℃ at a heating rate of 6℃ / min, and the holding time is 1h; the second stage is heated to 1450℃ at a heating rate of 4℃ / min, and the holding time is 2h; the tail gas generated in the sintering process is treated by absorption with a 0.5mol / L sodium hydroxide solution, then cooled to 500℃ at a rate of 6℃ / min, and then cooled to room temperature with the furnace, to obtain a coal gangue sintered brick.

[0051] Comparative Example 1

[0052] A preparation method of a coal gangue sintered brick, which is different from Example 1 in that quartz sandstone and manganese fluoride (MnF2) are not added, and the remaining steps are the same as those of Example 1.

[0053] Comparative Example 2

[0054] A preparation method of a coal gangue sintered brick, which is different from Example 1 in that manganese fluoride (MnF2) is not added, and the remaining steps are the same as those of Example 1.

[0055] Experimental detection

[0056] The properties of the coal gangue sintered bricks prepared in Examples 1-3 and Comparative Examples 1-2 were detected, and the detection standard was GB / T5101-2017 "Sintered Common Brick", and the detection results are shown in Table 3:

[0057] Table 3: Performance test results of sintered bricks

[0058] Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Compressive strength (MPa) 21.3 20.1 21.8 17.5 18.9 Brick porosity (%) 42.0 38.6 43.5 31.3 32.6 5h boiling water absorption (%) 14.5 14.8 14.6 15.4 15.7 Saturation coefficient 0.62 0.65 0.64 0.71 0.68 Blushing phenomenon No No No No No

[0059] As can be seen from Table 3, the sintered bricks prepared in Examples 1-3 have higher compressive strength, indicating excellent strength performance; the brick hole rate is higher, which can reflect its stronger heat preservation effect; the 5h boiling water absorption rate and the saturation coefficient are lower, indicating better weathering resistance. In summary, it can be concluded that the sintered bricks prepared in the examples of the present application have more excellent comprehensive performance.

[0060] In the description of the specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the specification, the illustrative description of the above terms should not be understood as necessarily referring to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any suitable manner in one or more embodiments or examples. In addition, those skilled in the art can combine and integrate different embodiments or examples described in the specification.

[0061] Although the embodiments of the present application have been shown and described above, it is understood that the above-described embodiments are exemplary, and should not be construed as limiting the present application, and those skilled in the art can make changes, modifications, replacements and variations to the above-described embodiments within the scope of the present application.

Claims

1. A method for preparing high-strength coal gangue sintered brick, characterized in that, The method comprises the following steps: Step 1, mixing the powders of coal gangue and quartz sandstone, crushing treatment by using a crusher to obtain a first mixture; Step 2, adding manganese fluoride into the first mixture, mixing with deionized water uniformly, and then placing in a ball mill for wet ball milling treatment to obtain a second mixture; Step 3, pressing the second mixture into a shape, and then placing in an oven for drying to obtain a precast brick blank; Step 4, placing the precast brick blank in a muffle furnace for temperature rising and sintering treatment, and then cooling to room temperature to obtain a coal gangue sintered brick.

2. The method for preparing high-strength coal gangue sintered bricks according to claim 1, characterized in that, In the step 1, the components of the coal gangue include: the mass percentage of SiO2 is 55.30%-62.52%, the mass percentage of Al2O3 is 17.21%-28.65%, the mass percentage of Fe2O3 is 1.35%-5.42%, the mass percentage of CaO is 1.12%-2.36%, the mass percentage of MgO is 0.53%-1.89%, and the mass percentage of TiO2 is 2.16%-3.57%.

3. The method for preparing high-strength coal gangue sintered bricks according to claim 1, characterized in that, In the step 1, the components of the quartz sandstone include: the mass percentage of SiO2 is 97.28%-97.36%, the mass percentage of Al2O3 is 0.95%-1.03%, and the mass percentage of Fe2O3 is 0.64%-0.68%.

4. The method for preparing high-strength coal gangue sintered bricks according to claim 1, characterized in that, In the step 1, the mass ratio of the coal gangue and the quartz sandstone is 2-5:1-3, and the crushing treatment is performed to a particle size of 5-10 mm.

5. The method for preparing high-strength coal gangue sintered bricks according to claim 1, characterized in that, In the step 2, the particle size of the manganese fluoride is 1-2 mm, and the addition amount of the manganese fluoride is 15%-35% of the mass of the first mixture.

6. The method for preparing high-strength coal gangue sintered bricks according to claim 1, characterized in that, In the step 2, the volume ratio of the total mass of the manganese fluoride and the first mixture to the deionized water is 1g:(0.8-1.2)mL.

7. The method for preparing high-strength coal gangue sintered bricks according to claim 1, characterized in that, In the step 2, during the ball milling treatment, the grinding balls are zirconium balls with a diameter of 3-5 mm, the ball-to-material ratio is 4-6:1, the ball milling speed is 300-400r / min, and the ball milling time is 5-8h.

8. The method for preparing high-strength coal gangue sintered bricks according to claim 1, characterized in that, In the step 3, the pressure for the pressing is 20-30MPa, the drying temperature in the oven is 60-80℃, and the drying time is 2-3h.

9. The method for preparing high-strength coal gangue sintered bricks according to claim 1, characterized in that, In the step 4, the temperature rising and sintering treatment process includes two stages: the first stage is to rise the temperature to 860-920℃ at a speed of 4-6℃ / min and keep the temperature for 0.5-1h; the second stage is to rise the temperature to 1220-1450℃ at a speed of 2-4℃ / min and keep the temperature for 1-2h.

10. The method for preparing high-strength coal gangue sintered bricks according to claim 1, characterized in that, In the step 4, the cooling process includes two stages: the first stage is to continuously cool to 500℃ at a speed of 4-6℃ / min after the temperature rising and sintering treatment is completed; the second stage is to cool from 500℃ to room temperature without controlling the cooling speed, and the furnace cooling to room temperature is allowed.

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