Concrete material based on coal gangue and preparation method thereof

Abstract

The invention discloses a concrete material based on coal gangue and a preparation method thereof. The concrete material based on the coal gangue comprises the following raw materials in parts by weight: 30-50 parts of cement, 200-250 parts of the coal gangue, 40-60 parts of iron tailing powder, 10-15 parts of limestone powder, 20-40 parts of fly ash, 20-40 parts of iron alloy slag, 5-10 parts of bauxite, 5-8 parts of superfine silicon dioxide, 4-6 parts of sodium hydroxide, 2-4 parts of sodium thiosulfate, 2-4 parts of a water reducing agent and 60-80 parts of water. According to the mixed concrete material, through selection of the raw material components, recycling of waste resources such as the coal gangue, the iron tailings and the iron alloy slag is achieved, in addition, through interaction among the raw materials, the interface performance among the coal gangue, the iron tailings, the iron alloy slag and the cement can be improved, interaction among the raw materials is improved, and the utilization rate of the raw materials is improved. The hydration reaction is promoted, and the cross-linking reaction among the raw materials is realized, so that the overall mechanical property of the prepared mixed concrete is improved.

Description

Technical Field

[0001] The invention relates to the technical field of resource utilization, and in particular to a concrete material based on coal gangue and a preparation method thereof. Background Art

[0002] Coal gangue is solid waste discharged during the coal mining and coal washing process. It is a kind of black-gray rock with low carbon content and harder than coal that is associated with coal seams during the coal formation process. It includes excavation gangue during tunnel excavation, gangue mined from the roof, floor and interlayer during mining, and washed gangue picked out during coal washing. Its main components are Al2O3 and SiO2. It also contains varying amounts of Fe2O3, CaO, MgO, Na2O, K2O, P2O5, SO3 and trace rare elements (gallium, vanadium, titanium, cobalt).

[0003] If coal gangue is abandoned, it will occupy large tracts of land; the escape or leaching of sulfides in the coal gangue will pollute the atmosphere, farmland and water bodies; gangue mountains will also spontaneously combust and cause fires, or collapse during the rainy season, clogging rivers and causing disasters.

[0004] Iron tailings are waste after ore dressing and are the main component of industrial solid waste. According to incomplete statistics, more than 10 billion tons of tailings and waste rock are discharged worldwide each year. At present, the resource utilization of iron tailings generally includes the recovery of valuable elements, building materials, ceramic materials, etc. Among building materials, iron tailings are mainly used to prepare concrete, permeable bricks and other products. However, the mechanical properties of concrete materials prepared in the existing technology are relatively low.

[0005] In view of this, the present invention is proposed. Summary of the invention

[0006] The object of the present invention is to provide a concrete material based on coal gangue and a preparation method thereof. The concrete material of the present invention realizes the reuse of waste resources such as coal gangue, iron tailings and ferroalloy slag through the selection of various raw material components, and makes the prepared concrete material have excellent mechanical properties.

[0007] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

[0008] A first aspect of the present invention provides a concrete material based on coal gangue, wherein the concrete material based on coal gangue comprises the following raw materials in parts by weight:

[0009] 30-50 parts of cement, 200-250 parts of coal gangue, 40-60 parts of iron ore tailings powder, 10-15 parts of limestone powder, 20-40 parts of fly ash, 20-40 parts of ferroalloy slag, 5-10 parts of bauxite, 5-8 parts of ultrafine silica, 4-6 parts of sodium hydroxide, 2-4 parts of sodium thiosulfate, 2-4 parts of water reducer and 60-80 parts of water.

[0010] Preferably, the gangue-based concrete material comprises the following raw materials in parts by weight:

[0011] 40 parts of cement, 220 parts of coal gangue, 50 parts of iron ore tailings powder, 12 parts of limestone powder, 30 parts of fly ash, 30 parts of ferroalloy slag, 8 parts of bauxite, 6 parts of ultrafine silica, 5 parts of sodium hydroxide, 3 parts of sodium thiosulfate, 3 parts of water reducer and 70 parts of water.

[0012] Preferably, the coal gangue includes coal gangue powder and coal gangue blocks, and the mass ratio of the coal gangue powder to the coal gangue blocks is (0.8-1):1.

[0013] Preferably, the particle size of the coal gangue powder is not greater than 2 mm, and the content of coal gangue powder with a particle size below 0.8 mm is 70% to 80%.

[0014] Preferably, the content of the gangue blocks with a particle size of 12 to 18 mm is 20% to 30%, the content of the gangue blocks with a particle size of 8 to 12 mm is 30% to 50%, and the remainder is the gangue blocks with a particle size of 5 to 8 mm.

[0015] Preferably, the cement is Portland cement.

[0016] A second aspect of the present invention provides a method for preparing the above-mentioned coal gangue-based concrete material, the preparation method comprising the following steps:

[0017] (a) weighing each raw material according to weight;

[0018] (b) adding sodium hydroxide and sodium thiosulfate to water, and then adding coal gangue, iron ore tailings powder and limestone to stir for a period of time to obtain a mixture;

[0019] (c) adding ultrafine silicon dioxide, ferroalloy slag, cement, fly ash, and water reducing agent bauxite to the mixture and continuing to stir and mix to obtain the coal gangue-based concrete material.

[0020] Preferably, in step (b), the stirring time is 40 to 60 minutes.

[0021] Preferably, in step (c), the stirring and mixing time is continued for 1 to 2 hours.

[0022] Compared with the prior art, the beneficial effects of the present invention include at least:

[0023] The concrete material of the present invention realizes the reuse of waste resources such as coal gangue, iron tailings and ferroalloy slag through the selection of various raw material components. In addition, the raw materials of the present invention can improve the interface properties between coal gangue, iron tailings, ferroalloy slag and cement through interaction, enhance the interaction between the raw materials, promote hydration reaction, realize cross-linking reaction between the raw materials, and thus improve the overall mechanical properties of the prepared mixed concrete. DETAILED DESCRIPTION

[0024] The following embodiments of the technical solution of the present invention are described in detail in conjunction with the embodiments. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and are therefore only used as examples, and cannot be used to limit the protection scope of the present invention.

[0025] It should be noted that, unless otherwise specified, the technical terms or scientific terms used in this application should have the common meanings understood by those skilled in the art to which the present invention belongs.

[0026] Unless otherwise specified, the raw materials used in the following embodiments can be purchased from the market; the iron tailings used in each embodiment are high-silicon iron tailings; the water reducer is a polycarboxylic acid-based water reducer with a water reduction rate of 25%; and the cement is 42.5# Portland cement.

[0027] Example 1

[0028] This embodiment is a concrete material based on coal gangue, and the concrete material based on coal gangue includes the following raw materials in parts by weight:

[0029] 30 parts of cement, 200 parts of coal gangue, 60 parts of iron ore tailings powder, 10 parts of limestone powder, 20 parts of fly ash, 40 parts of ferroalloy slag, 5 parts of bauxite, 8 parts of ultrafine silicon dioxide, 4 parts of sodium hydroxide, 4 parts of sodium thiosulfate, 2 parts of water reducer and 80 parts of water;

[0030] The coal gangue includes coal gangue powder and coal gangue blocks, and the mass ratio of the coal gangue powder to the coal gangue blocks is 0.8:1;

[0031] The particle size of coal gangue powder is not more than 2mm, and the content of coal gangue powder with a particle size less than 0.8mm is 70%;

[0032] The content of the coal gangue blocks with a particle size of 12 to 18 mm is 20%, the content of the coal gangue blocks with a particle size of 8 to 12 mm is 50%, and the remainder is the coal gangue blocks with a particle size of 5 to 8 mm.

[0033] The preparation method of the above-mentioned concrete material based on coal gangue comprises the following steps:

[0034] (a) weighing each raw material according to weight;

[0035] (b) adding sodium hydroxide and sodium thiosulfate to water, and then adding coal gangue, iron ore tailings powder and limestone and stirring for 40 minutes to obtain a mixture;

[0036] (c) adding ultrafine silicon dioxide, ferroalloy slag, cement, fly ash, and water reducing agent bauxite to the mixture and continuing to stir and mix for 2 hours to obtain the coal gangue-based concrete material.

[0037] Example 2

[0038] This embodiment is a concrete material based on coal gangue, and the concrete material based on coal gangue includes the following raw materials in parts by weight:

[0039] 50 parts of cement, 250 parts of coal gangue, 40 parts of iron ore tailings powder, 15 parts of limestone powder, 40 parts of fly ash, 20 parts of ferroalloy slag, 10 parts of bauxite, 5 parts of ultrafine silicon dioxide, 6 parts of sodium hydroxide, 2 parts of sodium thiosulfate, 4 parts of water reducer and 60 parts of water;

[0040] The coal gangue includes coal gangue powder and coal gangue blocks, and the mass ratio of the coal gangue powder to the coal gangue blocks is 1:1;

[0041] The particle size of the coal gangue powder is not greater than 2 mm, and the content of coal gangue powder with a particle size less than 0.8 mm is 80%;

[0042] The content of the coal gangue blocks with a particle size of 12 to 18 mm is 30%, the content of the coal gangue blocks with a particle size of 8 to 12 mm is 30%, and the remainder is the coal gangue blocks with a particle size of 5 to 8 mm.

[0043] The preparation method of the above-mentioned concrete material based on coal gangue comprises the following steps:

[0044] (a) weighing each raw material according to weight;

[0045] (b) adding sodium hydroxide and sodium thiosulfate to water, and then adding coal gangue, iron ore tailings powder and limestone and stirring for 60 minutes to obtain a mixture;

[0046] (c) adding ultrafine silicon dioxide, ferroalloy slag, cement, fly ash, and water reducing agent bauxite to the mixture and continuing to stir and mix for 1 hour to obtain the coal gangue-based concrete material.

[0047] Example 3

[0048] This embodiment is a concrete material based on coal gangue, and the concrete material based on coal gangue includes the following raw materials in parts by weight:

[0049] 40 parts of cement, 220 parts of coal gangue, 50 parts of iron ore tailings powder, 12 parts of limestone powder, 30 parts of fly ash, 30 parts of ferroalloy slag, 8 parts of bauxite, 6 parts of ultrafine silicon dioxide, 5 parts of sodium hydroxide, 3 parts of sodium thiosulfate, 3 parts of water reducer and 70 parts of water;

[0050] The coal gangue includes coal gangue powder and coal gangue blocks, and the mass ratio of the coal gangue powder to the coal gangue blocks is 1:1;

[0051] The particle size of coal gangue powder is not more than 2mm, and the content of coal gangue powder with particle size less than 0.8mm is 75%;

[0052] The content of the coal gangue blocks with a particle size of 12 to 18 mm is 25%, the content of the coal gangue blocks with a particle size of 8 to 12 mm is 40%, and the remainder is the coal gangue blocks with a particle size of 5 to 8 mm.

[0053] The preparation method of the above-mentioned concrete material based on coal gangue comprises the following steps:

[0054] (a) weighing each raw material according to weight;

[0055] (b) adding sodium hydroxide and sodium thiosulfate into water, and then adding coal gangue, iron ore tailings powder and limestone and stirring for 50 min to obtain a mixture;

[0056] (c) adding ultrafine silicon dioxide, ferroalloy slag, cement, fly ash, and water reducing agent bauxite to the mixture and continuing to stir and mix for 2 hours to obtain the coal gangue-based concrete material.

[0057] Comparative Example 1

[0058] This comparative example is a concrete material based on coal gangue, and the concrete material based on coal gangue includes the following raw materials in parts by weight:

[0059] 40 parts of cement, 270 parts of coal gangue, 12 parts of limestone powder, 30 parts of fly ash, 30 parts of ferroalloy slag, 8 parts of bauxite, 6 parts of ultrafine silicon dioxide, 5 parts of sodium hydroxide, 3 parts of sodium thiosulfate, 3 parts of water reducer and 70 parts of water;

[0060] The coal gangue includes coal gangue powder and coal gangue blocks, and the mass ratio of the coal gangue powder to the coal gangue blocks is 1:1;

[0061] The particle size of coal gangue powder is not more than 2mm, and the content of coal gangue powder with particle size less than 0.8mm is 75%;

[0062] The content of the coal gangue blocks with a particle size of 12 to 18 mm is 25%, the content of the coal gangue blocks with a particle size of 8 to 12 mm is 40%, and the remainder is the coal gangue blocks with a particle size of 5 to 8 mm.

[0063] The preparation method of the above-mentioned concrete material based on coal gangue comprises the following steps:

[0064] (a) weighing each raw material according to weight;

[0065] (b) adding sodium hydroxide and sodium thiosulfate to water, and then adding coal gangue and limestone and stirring for 50 minutes to obtain a mixture;

[0066] (c) adding ultrafine silicon dioxide, ferroalloy slag, cement, fly ash, and water reducing agent bauxite to the mixture and continuing to stir and mix for 2 hours to obtain the coal gangue-based concrete material.

[0067] Comparative Example 2

[0068] This comparative example is a concrete material based on coal gangue, and the concrete material based on coal gangue includes the following raw materials in parts by weight:

[0069] 40 parts of cement, 220 parts of coal gangue, 50 parts of iron ore tailings powder, 12 parts of limestone powder, 30 parts of fly ash, 30 parts of ferroalloy slag, 8 parts of bauxite, 6 parts of ultrafine silicon dioxide, 8 parts of sodium hydroxide, 3 parts of water reducer and 70 parts of water;

[0070] The coal gangue includes coal gangue powder and coal gangue blocks, and the mass ratio of the coal gangue powder to the coal gangue blocks is 1:1;

[0071] The particle size of coal gangue powder is not more than 2mm, and the content of coal gangue powder with particle size less than 0.8mm is 75%;

[0072] The content of the coal gangue blocks with a particle size of 12 to 18 mm is 25%, the content of the coal gangue blocks with a particle size of 8 to 12 mm is 40%, and the remainder is the coal gangue blocks with a particle size of 5 to 8 mm.

[0073] The preparation method of the above-mentioned concrete material based on coal gangue comprises the following steps:

[0074] (a) weighing each raw material according to weight;

[0075] (b) adding sodium hydroxide to water, and then adding coal gangue, iron ore tailings powder and limestone and stirring for 50 minutes to obtain a mixture;

[0076] (c) adding ultrafine silicon dioxide, ferroalloy slag, cement, fly ash, and water reducing agent bauxite to the mixture and continuing to stir and mix for 2 hours to obtain the coal gangue-based concrete material.

[0077] Experimental example

[0078] The gangue-based concrete materials prepared in Example 3 and Comparative Examples 1-2 are obtained respectively;

[0079] The mechanical properties of the above different concrete materials based on coal gangue were tested according to the method in GB / T50081-2002, and the test results are shown in Table 1;

[0080] Table 1

[0081]

[0082] From Table 1, we can see that:

[0083] Compared with the comparative example, the gangue-based concrete material prepared in the embodiment of the present invention has more excellent mechanical properties.

[0084] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

Claims

1. A concrete material based on coal gangue, characterized in that: The concrete material based on coal gangue comprises the following raw materials in parts by weight: 30-50 parts of cement, 200-250 parts of coal gangue, 40-60 parts of iron ore tailings powder, 10-15 parts of limestone powder, 20-40 parts of fly ash, 20-40 parts of ferroalloy slag, 5-10 parts of bauxite, 5-8 parts of ultrafine silica, 4-6 parts of sodium hydroxide, 2-4 parts of sodium thiosulfate, 2-4 parts of water reducer and 60-80 parts of water.

2. The gangue-based concrete material according to claim 1, characterized in that: The concrete material based on coal gangue comprises the following raw materials in parts by weight: 40 parts of cement, 220 parts of coal gangue, 50 parts of iron ore tailings powder, 12 parts of limestone powder, 30 parts of fly ash, 30 parts of ferroalloy slag, 8 parts of bauxite, 6 parts of ultrafine silica, 5 parts of sodium hydroxide, 3 parts of sodium thiosulfate, 3 parts of water reducer and 70 parts of water.

3. The gangue-based concrete material according to claim 1, characterized in that: The coal gangue includes coal gangue powder and coal gangue blocks, and the mass ratio of the coal gangue powder to the coal gangue blocks is (0.8-1):

1.

4. The gangue-based concrete material according to claim 3, characterized in that: The particle size of the coal gangue powder is not greater than 2 mm, and the content of the coal gangue powder with a particle size lower than 0.8 mm is 70% to 80%.

5. The gangue-based concrete material according to claim 3, characterized in that: The content of the coal gangue blocks with a particle size of 12 to 18 mm is 20% to 30%, the content of the coal gangue blocks with a particle size of 8 to 12 mm is 30% to 50%, and the remainder is the coal gangue blocks with a particle size of 5 to 8 mm.

6. The gangue-based concrete material according to claim 1, characterized in that: The cement is silicate cement.

7. The method for preparing a concrete material based on coal gangue according to any one of claims 1 to 6, characterized in that: The preparation method comprises the following steps: (a) weighing each raw material according to weight; (b) adding sodium hydroxide and sodium thiosulfate to water, and then adding coal gangue, iron ore tailings powder and limestone and stirring for a period of time to obtain a mixture; (c) adding ultrafine silicon dioxide, ferroalloy slag, cement, fly ash, and water reducing agent bauxite to the mixture and continuing to stir and mix to obtain the coal gangue-based concrete material.

8. The preparation method according to claim 7, characterized in that: In the step (b), the stirring time is 40 to 60 minutes.

9. The preparation method according to claim 7, characterized in that: In the step (c), the stirring and mixing time is continued for 1 to 2 hours.

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