CN111848037A

CN111848037A - Composition for preparing slate tailing brick, tailing brick and preparation method thereof

Info

Publication number: CN111848037A
Application number: CN202010706708.4A
Authority: CN
Inventors: 康馨; 王巍瑾; 陈仁朋; 杨微
Original assignee: Hunan University
Current assignee: Hunan University
Priority date: 2020-07-21
Filing date: 2020-07-21
Publication date: 2020-10-30
Anticipated expiration: 2040-07-21
Also published as: CN111848037B

Abstract

The invention relates to the technical field of building materials, and discloses a composition for preparing a slate tailing brick, a tailing brick and a preparation method thereof. The composition comprises 35-75 mass% of slate tailings, 15-30 mass% of fly ash and 10-35 mass% of portland cement, based on the total mass of the composition. The preparation method of the tailing brick comprises the following steps: dry-mixing the slate tailings, the fly ash and the portland cement, and then adding water to mix uniformly to obtain a mixture; and pressing and forming the mixture, and then watering and maintaining to obtain the slate tailing brick. The tailing brick of the invention takes the slate tailing as a matrix, simultaneously, a large amount of industrial waste residue fly ash is digested, the brick can be prepared in a non-steaming and non-firing way, the preparation process is simplified, and the prepared slate tailing brick has better compressive strength.

Description

Composition for preparing slate tailing brick, tailing brick and preparation method thereof

Technical Field

The invention relates to the field of building materials, and particularly relates to a composition for preparing a slate tailing brick, a tailing brick and a preparation method of the tailing brick.

Background

Along with the rapid development of the building industry in China, the demand of the building bricks is also increasing. The brick for building can be divided into a sintered brick and a non-sintered brick according to different production processes, wherein the sintered brick is prepared by taking clay, shale, coal gangue or fly ash as raw materials and carrying out molding and high-temperature roasting, and because most of the raw materials of the traditional sintered brick adopt clay, part of culturable land is reduced, the state has formally implemented a policy of forbidding using solid clay bricks in 2005, and takes the development and popularization of novel sintered bricks (for example, shale replaces clay) as means, so that the aim of promoting building energy conservation is achieved, but air pollution and water pollution caused in the sintering process are also one of main factors for restricting the development of the sintered bricks; the non-sintered brick used at present is not sintered in a brick kiln and has no ultrahigh hardness and durability.

With the continuous promotion of city and road construction in China, the vigorous development of rock mining and processing enterprises is effectively promoted in order to meet the requirements of the brick and tile market for construction. When the slate or the filler used for the production and construction of the slate ore is utilized, a large amount of slate tailings can be generated, the particle size of the tailings is small, the tailings are difficult to stack, dust pollution is easily caused, and the requirement of sustainable development of enterprises is restrained. How to effectively utilize the tile rock ore and change the waste into valuable becomes an important subject to be solved urgently.

Disclosure of Invention

The invention aims to overcome the problems in the prior art and provide a composition for preparing a slate tailing brick, the tailing brick and a preparation method thereof.

In order to achieve the above object, the present invention provides in a first aspect a composition for use in the preparation of a slate tailing brick, the composition comprising 35 to 75 mass% of slate tailing, 15 to 30 mass% of fly ash and 10 to 35 mass% of portland cement, based on the total amount of the composition.

Preferably, the composition comprises 40-65 mass% of the slate tailings, 20-25 mass% of the fly ash, and 15-35 mass% of the portland cement.

Further preferably, the particle size distribution of the slate tailings is not less than 90% in the range of 0.5-30 μm.

Further preferably, the fly ash is first grade fly ash.

Further preferably, the portland cement is ordinary portland cement.

In a second aspect, the invention provides a preparation method of a slate tailing brick, which comprises the following steps:

Dry-mixing the slate tailings, the fly ash and the portland cement, and then adding water to mix uniformly to obtain a mixture; pressing and forming the mixture, and then watering and maintaining to obtain the slate tailing bricks;

wherein, the total mass of the slate tailings, the fly ash and the portland cement is 100%, the mass of the slate tailings is 35-75%, the mass of the fly ash is 15-30%, the mass of the portland cement is 10-35%, and the mass of the water is 10-20% of the total mass of the slate tailings, the fly ash and the portland cement.

Preferably, the weight percentage of the slate tailings is 40-65%, the weight percentage of the fly ash is 20-25%, and the weight percentage of the portland cement is 15-35%.

Preferably, the particle size distribution of the slate tailings is not less than 90% in the range of 0.5-30 μm.

Preferably, the fly ash is a first grade fly ash.

Preferably, the portland cement is ordinary portland cement.

Further preferably, the dry mixing time is 1-5 min; stirring for 8-12min after adding water; the pressure of the pressing is 5-10Mpa, and the time is 2-5 min; the watering and curing time is 12-48 h.

In a third aspect, the invention provides a tailing brick prepared by the preparation method of the slate tailing brick.

Through the technical scheme, the invention has the beneficial effects that:

the invention takes the slate tailings as the matrix and combines the industrial waste residue fly ash, thereby saving the cost and realizing the reasonable utilization of the slate tailings resource and the solid waste resource. The slate tailing brick prepared by the invention can be prepared in a steaming-free and baking-free mode, so that the production steps are simplified, and the environmental pollution is avoided. Meanwhile, the slate tailings contain more SiO₂The components can effectively improve the compressive strength of the tailing brick, the unconfined compressive strength of the tailing brick can reach 26Mpa at most, and the tailing brick meets the requirements of JC/T422-2007 non-sintered refuse tailing brick in the aspects of water absorption and the like. The slate tailing brick can obtain tailing bricks with different strengths in different proportions, provides a new way for reasonable secondary utilization of tailings and solid wastes, reduces energy consumption, effectively reduces environmental pollution caused by sintered bricks, and can generate good social benefit, economic benefit and environmental benefit.

Drawings

FIG. 1 is an XRD pattern of fly ash;

figure 2 is an XRD pattern of slate tailings.

Detailed Description

The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

In a first aspect, the present invention provides a composition for use in the preparation of a slate tailing brick, the composition comprising 35 to 75 mass% of slate tailing, 15 to 30 mass% of fly ash and 10 to 35 mass% of portland cement, based on the total amount of the composition.

Wherein the main components of the slate tailings are quartz, calcium carbonate, clinopodium and multiferroic muscovite, and the main components are quartz, calcium carbonate, clinopodium and multiferroic muscovite which have chemical compositionsIs composed of SiO₂、CaO、Fe₂O₃And Al₂O₃The main component of the fly ash is SiO₂And CaO. The main component of the portland cement is SiO₂、CaO、Fe₂O₃And Al₂O₃。

As a preferable scheme, in order to further enhance the compressive strength of the tile slate tailing brick, the composition contains 40-65 mass% of tile slate tailings, 20-25 mass% of fly ash and 15-35 mass% of portland cement.

The slate tailings can be slate tailings with any particle size, the fly ash can also be fly ash with any grade, certainly, in order to enable the slate tailings, the fly ash and the portland cement to be mixed more uniformly in the mixing process and further enhance the compressive strength of the slate mine, the particle size distribution of the slate tailings is 0.5-30 mu m and is not less than 90%, the part with larger particle size in the tailings can play a role of a framework in the brick forming process, and finally the strength of a test piece can also be improved; the fly ash is first-grade fly ash.

The portland cement may be one or more of ordinary portland cement, fly ash portland cement, and slag portland cement. Preferably ordinary portland cement.

Preferably, the particle size distribution of the slate tailings is not less than 90% in the range of 0.5-30 μm; the fly ash is first-grade fly ash; the portland cement is ordinary portland cement.

The time of dry mixing, the stirring time after adding water and the pressing time can be adjusted by those skilled in the art according to the actual situation. Further preferably, the dry mixing time is 1-5min, and specifically may be 1min, 2min, 3min, 4min, 5min or any value between the two values; stirring for 8-12min after adding water, specifically 8min, 9min, 10min, 11min, 12min or any value between the above two values; the pressing pressure is 5-10MPa, the time is 2-5min, the pressure can be 5MPa, 6MPa, 7MPa, 8MPa, 9MPa, 10MPa or any value between the two values, and the time can be 2min, 3min, 4min, 5min or any value between the two values; the watering curing time is 12-48h, and specifically can be 12h, 24h, 36h, 48h or any value between the two values.

The present invention will be described in detail below by way of examples.

In the following examples, the particle size distribution and unconfined compressive strength were measured by an unconfined compression test of a sample under an axial pressure only test condition using a universal material testing machine; the density, the water absorption rate, the saturation coefficient, the freezing resistance, the softening resistance and the alkali resistance are respectively measured by methods GB/T4111-Buchner 2013 and non-sintered refuse tailing brick JC/T422-Buchner 2007. Fly ash portland cement was purchased from southern cement limited, Liuyang, Hunan. The slate mine tailings are purchased from a mine site in the argao county of Shanxi province. The iron ore tailings are purchased from ore dressing plants belonging to Ningshan mining industries, Inc., of cupling, Anhui province.

Fly ash

The fly ash used in the invention is taken from a certain coal-fired thermal power plant in Henan, the fine ash captured from the flue gas after coal combustion is taken as first-grade fly ash, and a sample is taken after drying for X-ray diffraction analysis, and the result is shown in figure 1. From the XRD image of the fly ash in FIG. 1, the mineral composition of the fly ash is mainly mullite. The chemical composition of this fly ash is shown in table 1.

TABLE 1 main chemical composition of fly ash

Oxide compound	SiO₂	Al₂O₃	Fe₂O₃	CaO	K₂O	TiO₂
							Content (%)	51.95	30.59	6.53	4.77	1.80	1.43

SiO in the fly ash₂And Al₂O₃The highest contents were 51.95% and 30.59%, respectively.

Slate tailings

The slate tailings used in the method are taken from a certain slate mine site in the langat county of Shanxi province, and are crushed and dried to obtain slate tailing powder required by an experiment for later use. A small amount of slate tailings are taken, and after X-ray diffraction analysis, the main mineral composition of the slate tailings is shown in figure 2. As can be seen from the XRD image of the slate shown in figure 2, the main components of the mineral composition of the slate tailings are quartz, calcium carbonate, clinopodium, and multiferroic muscovite. The chemical composition and particle size analysis of the slate tailings are shown in Table 2.

TABLE 2 chemical composition of shingle rock tailings

Oxide compound	SiO₂	CaO	Fe₂O₃	Al₂O₃	MgO
						Content (%)	41.02	32.44	9.21	8.99	5.28

SiO is contained in the slate tailings₂Mostly, and then CaO and Fe ₂O₃、Al₂O₃This isThe components are easy to generate hydration and gelation reactions, so that the strength of the product is improved.

Ordinary portland cement

The cement used in the invention is P.O42.5 ordinary portland cement, and the manufacturer is southern cement limited of Hunan Liuyang. The main components are as follows:

TABLE 3P.O 42.5.5 chemical composition of Portland Cement

Oxide compound	CaO	SiO₂	Fe₂O₃	Al₂O₃	SO₃
						Content (%)	69.21	17.01	3.75	3.62	2.99

In the invention, after the slate mine, the fly ash and the portland cement are mixed, CaO and SiO in the slate mine and the fly ash are contained₂、Al₂O₃The components and the Portland cement are subjected to hydration reaction to generate gel of hydrated calcium silicate and gel of hydrated calcium ferrite, and the reaction is followedBecause the generation speed of hydrate is higher than the diffusion speed, a large amount of gel is accumulated on the surfaces of the particles, and the reaction is continuously carried out, so that a new gel structure with a thick layer of gel film wrapped outside is generated. The reaction is continued, the water content in the brick blank is gradually reduced, the intermolecular distance of the gel structure is gradually reduced, the attraction is increasingly large, the adhesive force is increased, and the molecules are combined with each other by the intermolecular interaction force (adhesive force) to form a gradually regular crystal. The crystals and the colloid are mutually staggered to form a net shape, the crystals and the slate aggregate together play a main role of a bearing framework, the colloid plays a role of cementation, and the aggregate is closely combined with a cementing material to form a compact brick blank.

During curing, the hydration reaction and the cementation and hardening reaction continue continuously and slowly with the reduction of moisture and the action of oven heating, and the rational strength is stably achieved after 1 day of oven curing.

Example 1

(1) Carrying out dry mixing on 240kg of the slate tailings (the particle size distribution is 0.5-30 mu m and accounts for 95 percent), 80kg of fly ash and 60kg of ordinary portland cement in a stirrer for 3min, then adding 60kg of water, uniformly mixing and stirring for 10min to obtain a mixture;

(2) and (2) pouring the mixture obtained in the step (1) into a brick making machine, pressing for 3min at 8MPa for forming, transferring the formed green brick into a curing room, and carrying out water spraying curing for 24h to obtain the tailing brick.

The unconfined compressive strength of the tailing brick reaches 20.37MPa, and the density is 1893.92kg/m³The water absorption, saturation coefficient, frost resistance, softening resistance and alkali resistance all reach the levels of MU20 in the non-sintered refuse tailing brick of the national standard.

Example 2

(1) 192kg of slate tailings (the granularity distribution is 0.5-30 mu m and accounts for 93 percent), 88kg of fly ash and 120kg of ordinary portland cement are dry-mixed in a stirrer for 3min, and then 60kg of water is added to be uniformly mixed and stirred for 12min, so as to obtain a mixture;

(2) and (2) pouring the mixture obtained in the step (1) into a brick making machine, pressing for 2min at 10MPa for forming, transferring the formed green brick into a curing room, and carrying out water spraying curing for 24h to obtain the tailing brick.

The unconfined compressive strength of the tailing brick reaches 26.00MPa, and the density of the tailing brick reaches 1861.50kg/m³The water absorption, saturation coefficient, frost resistance, softening resistance and alkali resistance all reach the levels of MU25 in the non-sintered refuse tailing brick of the national standard.

Example 3

(1) The method comprises the following steps of dry-mixing 160kg of slate tailings (the granularity distribution is 0.5-30 mu m and accounts for 90 percent), 100kg of first-grade fly ash and 140kg of fly ash portland cement in a stirrer for 1min, and then adding 40kg of water, uniformly mixing and stirring for 12min to obtain a mixture;

(2) and (2) pouring the mixture obtained in the step (1) into a brick making machine, pressing for 5min at 9MPa for forming, transferring the formed green brick into a curing room, and carrying out water spraying curing for 12h to obtain the tailing brick.

The unconfined compressive strength of the tailing brick reaches 23.5MPa, and the density is 1794kg/m³The water absorption, saturation coefficient, frost resistance, softening resistance and alkali resistance all reach the levels of MU20 in the non-sintered refuse tailing brick of the national standard.

Example 4

(1) Dry-mixing 140kg of slate tailings (the granularity distribution is 0.5-30 mu m and accounts for 90 percent), 120kg of first-grade fly ash and 140kg of ordinary portland cement in a stirrer for 3min, then adding 60kg of water, uniformly mixing and stirring for 10min to obtain a mixture;

(2) and (2) pouring the mixture obtained in the step (1) into a brick making machine, pressing for 3min at 5MPa for forming, transferring the formed green brick into a curing room, and carrying out water spraying curing for 24h to obtain the tailing brick.

The unconfined compressive strength of the tailing brick reaches 19.87MPa, and the density is 1785.46kg/m³The water absorption, saturation coefficient, frost resistance, softening resistance and alkali resistance all reach the levels of MU15 in the non-sintered refuse tailing brick of the national standard.

Example 5

(1) 288kg of the slate tailings (the granularity distribution is 0.5-30 mu m and accounts for 90 percent), 72kg of the first-grade fly ash and 40kg of ordinary portland cement are dry-mixed in a stirrer for 3min, and then 60kg of water is added to be uniformly mixed and stirred for 10min, so as to obtain a mixture;

The unconfined compressive strength of the tailing brick reaches 16.68MPa, and the density of the tailing brick reaches 1758.33kg/m³The water absorption, saturation coefficient, frost resistance, softening resistance and alkali resistance all reach the levels of MU15 in the non-sintered refuse tailing brick of the national standard.

Example 6

(1) Carrying out dry mixing on 300kg of the slate tailings (the granularity distribution is 0.5-30 mu m and accounts for 90 percent), 60kg of first-grade fly ash and 40kg of ordinary portland cement in a stirrer for 5min, and then adding 80kg of water, uniformly mixing and stirring for 10min to obtain a mixture;

(2) and (2) pouring the mixture obtained in the step (1) into a brick making machine, pressing for 2min at 6MPa for forming, transferring the formed green brick into a curing room, and carrying out water spraying curing for 24h to obtain the tailing brick.

The unconfined compressive strength of the tailing brick reaches 15.83MPa, and the density of the tailing brick reaches 1753.55kg/m³The water absorption, saturation coefficient, frost resistance, softening resistance and alkali resistance all reach the levels of MU15 in the non-sintered refuse tailing brick of the national standard.

Example 7

(1) Carrying out dry mixing on 240kg of the slate tailings (the granularity distribution is 0.5-30 mu m and accounts for 88%), 80kg of first-grade fly ash and 60kg of ordinary portland cement in a stirrer for 3min, then adding 60kg of water, uniformly mixing and stirring for 10min to obtain a mixture;

The unconfined compressive strength of the tailing brick reaches 16.32MPa, and the density of the tailing brick reaches 1836.23kg/m³The water absorption, saturation coefficient, frost resistance, softening resistance and alkali resistance all reach the levels of MU15 in the non-sintered refuse tailing brick of the national standard.

Comparative example

(1) Dry-mixing 328kg of iron ore tailings (the proportion of particles with the particle size of less than 74 microns is more than 70 percent), 32kg of first-grade fly ash and 40kg of ordinary portland cement in a stirrer for 5min, then adding 64kg of water, uniformly mixing and stirring for 2min to obtain a mixture;

(2) and (2) pouring the mixture obtained in the step (1) into a brick making machine, pressing for 3min at 10MPa for forming, transferring the formed green brick into a curing room, and carrying out water spraying curing for 28 days to obtain the tailing brick.

The unconfined compressive strength of the tailing brick reaches 14.68MPa, and the density of the tailing brick reaches 1738.58kg/m³The compressive strength of the brick is less than 15Mpa, and the brick does not reach the MU15 grade of the national standard 'non-sintered refuse tailing brick'.

The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.

Claims

1. A composition for use in the preparation of a slate tailing brick, characterized in that the composition comprises 35 to 75 mass% of slate tailing, 15 to 30 mass% of fly ash and 10 to 35 mass% of portland cement, based on the total amount of the composition.

2. The composition for making a slate tailing brick according to claim 1, wherein the composition comprises 40-65 mass% of slate tailing, 20-25 mass% fly ash, and 15-35 mass% portland cement.

3. The composition for preparing a slate tailing brick according to claim 1 or 2, wherein the particle size distribution of the slate tailing is not less than 90% in the range of 0.5 to 30 μ ι η.

4. The composition for preparing a slate tailing brick according to claim 1 or 2, wherein the fly ash is a primary fly ash.

5. The composition for making slate tailing bricks according to claim 1 or 2, wherein the portland cement is ordinary portland cement.

6. The preparation method of the slate tailing brick is characterized by comprising the following steps:

7. The preparation method of the slate tailing brick according to claim 6, wherein the slate tailing accounts for 40-65 mass%, the fly ash accounts for 20-25 mass%, and the portland cement accounts for 15-35 mass%.

8. The method for preparing the slate tailing brick according to claim 6, wherein the particle size distribution of the slate tailing is not less than 90% in the range of 0.5-30 μm;

the fly ash is first-grade fly ash;

the portland cement is ordinary portland cement.

9. The method of making a slate tailing brick according to any of claims 6 to 8, wherein the dry blending time is 1-5 min; stirring for 8-12min after adding water; the pressure of the pressing is 5-10Mpa, and the time is 2-5 min; the watering and curing time is 12-48 h.

10. A tailing brick produced by the method for producing a slate tailing brick according to any one of claims 6 to 9.