High-strength glass-ceramic-based lightweight aggregates and preparation method thereof

Abstract

The invention discloses high-strength glass-ceramic-based lightweight aggregates and the preparation method thereof. The mass ratio of raw material components is 50-70 parts of engineering muck, 20-40 parts of glass, 3-7 parts of calcium carbonate, 3-7 parts of magnesium oxide, and 2-10 parts of a nucleating agent; the nucleating agent is at least one of calcium fluoride, titanium dioxide, and chromium oxide. After crushing, mixing, and granulating, spherical particles with a particle size of 10-12 mm are formed; and then the product can be obtained after drying, sintering, and cooling. The obtained lightweight aggregate from the invention has a diopside matrix which provides high strength and a low water absorption rate at low densities. Moreover, waste glass and engineering muck could be utilized with high value.

Claims

1. High-strength glass-ceramic-based lightweight aggregates, containing the following components in parts by mass: 50-70 parts of engineering muck, 20-40 parts of waste glass, 3-7 parts of calcium carbonate, 3-7 parts of magnesium oxide, and 2-10 parts of a nucleating agent; the nucleating agent is at least one of calcium fluoride, titanium dioxide, and chromium oxide; the sintering steps of the high-strength glass-ceramic-based lightweight aggregates are as follows: a first heating stage that raises the temperature from room temperature to 800° C. at a heating rate of 5-10° C./min; a nucleation phase that is maintained at 800° C. for 30-60 min; a second heating stage that raises the temperature from 800° C. to 1100-1180° C. at a heating rate of 10° C./min; a sintering phase that maintains at 1120-1180° C. for 1 h and then cools down to room temperature.

2. The high-strength glass-ceramic-based lightweight aggregates according to claim 1, containing the following components in parts by mass: 50-70 parts of engineering muck, 20-40 parts of waste glass, 5 parts of calcium carbonate, 5 parts of magnesium oxide and 2-10 parts of a nucleating agent; the nucleating agent is at least one of calcium fluoride, titanium dioxide, and chromium oxide.

3. The high-strength glass-ceramic-based lightweight aggregates according to claim 2, wherein the engineering muck is brown muck produced in underground engineering development, which is crushed before use and then dried at 105° C. for 48 h.

4. The high-strength glass-ceramic-based lightweight aggregates according to claim 2, wherein the calcium carbonate and magnesium oxide are analytically pure; the waste glass is waste colorless transparent flat glass.

5. The high-strength glass-ceramic-based lightweight aggregates according to claim 1 are used to prepare building materials.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Accompanying drawings provide a further understanding of embodiments of the disclosure. The drawings form a part of the disclosure and illustrate the principle of the embodiments of the disclosure along with the literal description. Apparently, the drawings in the description below are merely some embodiments of the disclosure. A person skilled in art can obtain other drawings according to these drawings without creative efforts. In the figures:

(2) FIG. 1 is an internal micrograph of the high-strength glass-ceramic-based lightweight aggregate prepared in Example 1;

(3) FIG. 2 is an external micrograph of the high-strength glass-ceramic-based lightweight aggregate in Example 1;

(4) FIG. 3 is an internal micrograph of the high-strength glass-ceramic-based lightweight aggregate prepared in Example 2;

(5) FIG. 4 is an external micrograph of the high-strength glass-ceramic-based lightweight aggregate prepared in Example 2;

(6) FIG. 5 is an internal micrograph of the high-strength glass-ceramic-based lightweight aggregate in Example 3;

(7) FIG. 6 is an external micrograph of the high-strength glass-ceramic-based lightweight aggregate in Example 3.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

(8) The invention will be further described in detail in combination with embodiments to make the purpose, technical scheme, and advantages of the invention clear. The specific embodiments described herein are only used to explain the invention and are not intended to limit the invention.

Example 1

(9) This embodiment provides a method for preparing a high-strength glass-ceramic-based lightweight aggregate, including the following steps:

(10) (1) Preparation of raw materials: firstly, the engineering muck is crushed and put into a drier for drying at 105° C. for 48 h. Then, the components of the waste glass (transparent plate glass), engineering muck, analytically pure calcium carbonate, analytically pure magnesium oxide, and calcium fluoride are crushed and ball-milled, respectively. The powder with a sieve residue of less than 5% is obtained through a 200 mesh sieve. Then weigh the above powder according to the mix proportion. Specifically, the mass ratio of the waste glass, engineering muck, analytical pure calcium carbonate, analytical pure magnesium oxide, and calcium fluoride is 50:40:5:5:2.

(11) (2) Raw material mixing, raw spherical pellets preparing, and drying: putting all powder raw materials into the blender and mix for 4 hours at 120 r/min to get the mixture; Then, add 30-40% water of the mixture, and the pellets with a diameter of 10-12 mm are formed by a granulator. Put the pellets into an oven and dry them for 4 h at 105° C. to obtain dry raw spherical pellets.

(12) (3) Sintering of LWAs: putting the raw spherical pellets into a muffle furnace, and the sintering regime are as follows: raising the temperature from room temperature to 800° C. at a heating rate of 5° C./min and maintaining at 800° C. for 1 h; then raising the temperature from 800° C. to 1150° C. at a heating rate of 10° C./min, and maintaining at 1150° C. for 1 h; then naturally cooling to room temperature to get the product.

(13) The apparent density of the LWAs prepared in Example 1 is 1110 kg/m.sup.3 (the bulk density is about 600 kg/m.sup.3), the 24 h water absorption rate is 0.389%, and the single particle crushing strength is 14.01 MPa. The experimental data is obtained from 10 LWAs with similar sizes and regular shapes, and their average strength is calculated.

Example 2

(14) This embodiment provides a method for preparing high-strength glass-ceramic-based LWAs, including the following steps:

(15) (1) Preparation of raw materials: firstly, the engineering muck is crushed and put into a drier for drying at 105° C. for 48 h. Then, the components of the waste glass (transparent plate glass), engineering muck, analytically pure calcium carbonate, analytically pure magnesium oxide, and calcium fluoride are crushed and ball-milled, respectively. The powder with a sieve residue of less than 5% is obtained through a 200 mesh sieve. Then weigh the above powder according to the mass ratio. Specifically, the mass ratio of the waste glass, building residue, analytical pure calcium carbonate, analytical pure magnesium oxide, and calcium fluoride is 50:40:5:5:2.

(16) (2) Raw material mixing, raw spherical pellets preparing, and drying: putting all powder raw materials into the blender and mix for 4 hours at 120 r/min to get the mixture; Then, add 30-40% water of the mixture, and the pellets with a diameter of 10-12 mm are formed by a granulator. Put the pellets into an oven and dry them for 4 h at 105° C. to obtain dry raw spherical pellets.

(17) (3) Sintering of LWAs: putting the raw spherical pellets into a muffle furnace, and the sintering regime are as follows: raising the temperature from room temperature to 800° C. at a heating rate of 5° C./min and maintaining at 800° C. for 1 h; then raising the temperature from 800° C. to 1180° C. at a heating rate of 10° C./min, and maintaining at 1180° C. for 1 h; then naturally cooling to room temperature to get the product.

(18) The apparent density of the product prepared in Example 2 is 930 kg/m.sup.3 (the bulk density is about 500 kg/m.sup.3), the 24 h water absorption rate is 2.224%, and the single particle crushing strength is 10.07 MPa. The experimental data is obtained from 10 LWAs with similar sizes and regular shapes, and their average strength is calculated.

(19) At 1180° C., the liquid viscosity of LWAs is lower. Therefore, a part of the gas will overflow the surface of LWAs during the expansion process, which forms connected pores in the inner matrix of LWAs, and the surface of LWAs will also form pores. This is the reason why the water absorption of LWAs increases. At the same time, the porous surface and low density reduced the strength.

Example 3

(20) This embodiment provides a method for preparing high-strength glass-ceramic-based LWAs, including the following steps:

(21) (1) Preparation of raw materials: firstly, the engineering muck is crushed and put into a drier for drying at 105° C. for 48 h. Then, the components of the waste glass (transparent plate glass), engineering muck, analytically pure calcium carbonate, analytically pure magnesium oxide, and calcium fluoride are crushed and ball-milled, respectively. The powder with a sieve residue of less than 5% is obtained through a 200 mesh sieve. Then weigh the above powder according to the mass ratio. Specifically, the mass ratio of the waste glass, engineering muck, analytical pure calcium carbonate, analytical pure magnesium oxide, and calcium fluoride is 70:20:5:5:2.

(22) (2) Raw material mixing, raw spherical pellets forming and drying: putting raw materials into the blender and mixing for 4 hours at 120 r/min to get the mixture; Then, add 30-40% water of the mixture and the pellets with a diameter of 10-12 mm are formed by a granulator. Put the pellets into an oven and dry them for 4 h at 105° C. to obtain dry raw spherical pellets.

(23) (3) Sintering of LWAs: putting the raw spherical pellets into a muffle furnace, and the sintering conditions are as follows: raising the temperature from room temperature to 800° C. at a heating rate of 5° C./min and maintaining at 800° C. for 1 h; then raising the temperature from 800° C. to 1120° C. at a heating rate of 10° C./min, and maintaining at 1120° C. for 1 h; then naturally cooling to room temperature to get the product.

(24) The apparent density of the product prepared in Example 3 is 1090 kg/m.sup.3 (the bulk density is about 600 kg/m.sup.3), the 24 h water absorption rate is 0.479%, and the single particle crushing strength is 13.93 MPa. The experimental data is obtained from 10 LWAs with similar sizes and regular shapes, and their average strength is calculated.

(25) FIG. 1 is an internal micrograph of the high-strength glass-ceramic-based lightweight aggregates prepared in Example 1. Microcrystalline phases (long columnar shape) are intertwined, which differs from the microscopic morphology of conventional LWAs. The three-dimensional network structure is composed of microcrystalline phases that significantly improve the strength of LWAs.

(26) FIG. 2 is an external micrograph of the high-strength glass-ceramic-based LWAs prepared in Example 1. Although there are microcrystalline phases on the surface of LWAs, the distribution density is less than that inside. The surface is still dominated by the dense glass phase, which is conducive to reducing the water absorption of LWAs.

(27) The LWAs prepared in Examples 2-3 have an external and internal structure similar to that in Example 1, as shown in FIGS. 3-6.

(28) The above descriptions are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc., made within the spirit and principle of the present invention shall be included in the protection of the present invention.