CN107032704B - It is a kind of for preventing and treating the cement foam material of spontaneous combustionof coal - Google Patents

Abstract

The invention discloses a cement foam material for preventing spontaneous combustion of coal, comprising the following raw materials in parts by weight: Portland cement 88-91.2, sodium metaaluminate 2-2.5, calcium chloride 1.5-2, carboxymethyl Cellulose sodium 0.3-0.5, sodium dodecylbenzene sulfonate 2-3, saponin 2-4, water 55-60. The cement foam material used for preventing and controlling spontaneous combustion of coal has the advantages of high foaming ratio, strong stability, short solidification time, good flame retardant effect, strong leak-stopping performance, low cost, good flow and diffusivity, and can be accumulated in high places. The medium and high coal can be covered and wrapped, which has good permeability to coal and rock fissures, low material density and high compressive strength, and has wide applicability in the field of underground coal mine fire prevention.

Description

A kind of cement foam material for preventing spontaneous combustion of coal

technical field

The invention relates to the field of cement foam materials, in particular to a cement foam material used for preventing spontaneous combustion of coal.

Background technique

Coal spontaneous combustion is one of the main natural disasters affecting the safety of coal mine production. It not only wastes a lot of coal resources, but also may cause gas explosion accidents, resulting in heavy casualties and property losses.

In order to prevent spontaneous combustion of coal, technologies such as grouting, inert gas injection, gel injection, foam injection and chemical inhibitor spraying have been successively adopted in my country since the 1950s. These technologies have played a positive role in preventing coal spontaneous combustion in goaf areas, but they all have some shortcomings, such as: grouting, the slurry only flows along the lower terrain, and cannot evenly cover the middle and high coal bodies; inert gas injection, The gas is easy to diffuse with the air leakage, and it is not easy to stay in the injection area, and its fire extinguishing and cooling ability is also weak; gel injection, high cost, small flow, limited diffusion range; Long-lasting and effective prevention and control of spontaneous combustion of coal; spraying inhibitor, it is not easy to evenly disperse on the coal body, and it is easy to corrode underground equipment and endanger the physical and mental health of workers.

Therefore, the existing technology cannot effectively prevent spontaneous combustion of coal in coal mines and ensure safe mining in coal mines, which needs to be further improved and developed.

SUMMARY OF THE INVENTION

Aiming at the deficiencies of the existing coal mine fire-fighting technology, the purpose of the present invention is to provide a high foaming ratio, good fluidity, good flame retardant effect, strong blocking performance, fast setting time, low cost, and can be accumulated in high places. A cement foam material for preventing and controlling spontaneous combustion of coal and a preparation method thereof.

In order to solve the above-mentioned technical problems, the present invention adopts the following technical scheme: a cement foam material for preventing and controlling spontaneous combustion of coal, including the following raw materials in parts by weight: Portland cement 88-91.2, sodium metaaluminate 2-2.5, chlorine Calcium 1.5～2, Sodium carboxymethyl cellulose 0.3～0.5, Sodium dodecylbenzene sulfonate 2～3, Saponin 2～4, Water 55～60.

The raw materials selected in the present invention, sodium metaaluminate and calcium chloride have a certain accelerating effect, which can accelerate the hydration reaction process of cement, and sodium metaaluminate, calcium chloride and cement form slurry, and the three can occur between them. Reaction, improve the hydration process of cement, and play the role of rapid solidification of cement; sodium carboxymethyl cellulose can form a film at the interface between cement particles and air bubbles, play a lubricating role, improve the toughness of air bubbles, can Compressibility and life, at the same time can improve the fluidity and water retention of cement foam, improve the performance of cement foam after molding, sodium carboxymethyl cellulose can form a thickening solution, improve the water retention of cement foam, and can enhance its fluidity and pumpability; sodium dodecyl benzene sulfonate and saponin are compounded into a composite foaming agent, which can significantly reduce the surface tension of water, improve the foaming ability of the solution, and the prepared foam has excellent stability.

Further, the particle size of the Portland cement is 3-40 microns. In the process of implementing the present invention, the inventor found that Portland cement with a particle size of 3 to 40 microns can not only meet the initial strength requirements of the cement foam of the present invention, but also meet the requirements of fast setting time. When the particle size is below 3 microns, although The solidification time is fast, but the strength is small. When the particle size is above 40 microns, although the strength meets the requirements, the solidification time is too long.

The above-mentioned preparation method of the cement foam material for preventing and controlling spontaneous combustion of coal comprises the following steps:

(1) Mixing Portland cement, sodium metaaluminate and calcium chloride evenly to form composite cement powder;

(2) mixing water, sodium carboxymethyl cellulose, sodium dodecyl benzene sulfonate and saponin, and foaming by high-speed stirring to form foam;

(3) Under stirring conditions, the composite cement powder is added to the foam to prepare the cement foam material for preventing spontaneous combustion of coal.

The beneficial effects of the present invention are embodied in:

The cement foam material used for preventing and controlling spontaneous combustion of coal has high foaming ratio (8-10 times), strong stability, short setting time (30-40 minutes) and good flame retardant effect (heat transfer coefficient is 0.045-0.061W). /(m·K)), strong leakage blocking (can block gas pressure of 15Kpa), low cost, good flow diffusivity (viscosity is 4400-4600mpa·s), can be accumulated in high places, and is suitable for medium and high coal. It can cover and wrap, has good permeability to coal and rock fissures, low material density (density of 300-400kg/m3), high compressive strength (compressive strength of more than 1.5Mpa), and has a wide range of applicability in the field of underground coal mine fire prevention .

The preparation method of the cement foam material for preventing and controlling spontaneous combustion of coal has the advantages of simple process, convenient operation and low energy consumption, and is suitable for industrialized large-scale production.

The main raw materials of the invention are Portland cement, sodium metaaluminate, calcium chloride, etc., which have wide sources and simple operation process.

Detailed ways

The present invention will be described in detail below in conjunction with the embodiments.

Example 1

A cement foam material for preventing spontaneous combustion of coal, comprising the following raw materials by weight: Portland cement 89, sodium metaaluminate 2, calcium chloride 1.5, sodium carboxymethyl cellulose 0.3, dodecylbenzene Sodium sulfonate 2, saponin 2, water 55, the particle size of Portland cement is 3 microns.

The above-mentioned preparation method of the cement foam material for preventing and controlling spontaneous combustion of coal is as follows:

(1) Weigh Portland cement, sodium metaaluminate and calcium chloride according to the formula, put them into a dry-mixing mixer, fully stir (stirring rate is 40 rev/min) and mix to form composite cement powder for subsequent use;

(2) take by weighing water, sodium carboxymethyl cellulose, sodium dodecyl benzene sulfonate and saponin according to the formula, put them into the mixing container, and use an electric mixer to stir at high speed (the stirring speed is 3000 rev/min) to foam, When the foam volume is basically stable, stop stirring to make foam;

(3) Under the condition of stirring (the stirring speed is 950 rpm), the composite cement powder is slowly added (3 parts by weight per minute) into the foam, and the stirring is continued until a foam that can flow freely and has a certain consistency is formed The body is the cement foam material used for preventing spontaneous combustion of coal.

The cement foam material used for preventing spontaneous combustion of coal in this embodiment has a foaming ratio of 10 times, a solidification time of 30 to 33 minutes, a heat transfer coefficient of 0.045W/(m·K), and can block a gas pressure of 15Kpa. The viscosity is 4400mpa·s, the density is 300kg/m ³ , the compressive strength is up to 1.5Mpa, it can be piled up to high places, it can cover and wrap the medium and high coal, and it has good permeability to coal rock fissures and strong stability.

Example 2

A cement foam material for preventing spontaneous combustion of coal, comprising the following raw materials in parts by weight: Portland cement 91.2, sodium metaaluminate 2.5, calcium chloride 2, sodium carboxymethyl cellulose 0.5, dodecylbenzene Sodium sulfonate 3, saponin 4, water 60, the particle size of Portland cement is 25 microns.

The above-mentioned preparation method of the cement foam material for preventing and controlling spontaneous combustion of coal is as follows:

(1) Weigh Portland cement, sodium metaaluminate and calcium chloride according to the formula, put them into a dry-mixing mixer, fully stir (stirring rate is 40 rev/min) and mix to form composite cement powder for subsequent use;

(2) Weigh water, sodium carboxymethyl cellulose, sodium dodecyl benzene sulfonate and saponin according to the formula, put them into the mixing container, and use an electric mixer to stir at high speed (the stirring speed is 2850 rev/min) to foam, When the foam volume is basically stable, stop stirring to make foam;

(3) Under the condition of stirring (the stirring speed is 1000 rpm), the composite cement powder is slowly added into the foam (3 parts by weight per minute), and the stirring is continued until a foam that can flow freely and has a certain consistency is formed The body is the cement foam material used for preventing spontaneous combustion of coal.

The cement foam material used for preventing spontaneous combustion of coal in this embodiment has a foaming ratio of 9 times, a solidification time of 35 to 38 minutes, a heat transfer coefficient of 0.055W/(m·K), and can block a gas pressure of 15Kpa. The viscosity is 4530mpa·s, the density is 350kg/m ³ , and the compressive strength is 1.65Mpa. It can be piled up to high places, and can cover and wrap both medium and high coals. It has good permeability to coal rock fissures and strong stability.

Example 3

A cement foam material for preventing spontaneous combustion of coal, comprising the following raw materials by weight: Portland cement 88, sodium metaaluminate 2.3, calcium chloride 1.7, sodium carboxymethyl cellulose 0.34, dodecylbenzene Sodium sulfonate 2.5, saponin 3, water 58, the particle size of Portland cement is 40 microns.

The above-mentioned preparation method of the cement foam material for preventing and controlling spontaneous combustion of coal is as follows:

(1) Weigh Portland cement, sodium metaaluminate and calcium chloride according to the formula, put them into a dry-mixing mixer, fully stir (stirring rate is 40 rev/min) and mix to form composite cement powder for subsequent use;

(2) take by weighing water, sodium carboxymethyl cellulose, sodium dodecyl benzene sulfonate and saponin according to the formula, put into the mixing container, and use an electric mixer to stir at a high speed (the stirring speed is 3150 rev/min) to foam, When the foam volume is basically stable, stop stirring to make foam;

(3) Under the condition of stirring (the stirring rate is 1050 rpm), slowly (3 parts by weight/minute) the composite cement powder is added to the foam, and continue stirring until a foam that can flow freely and has a certain consistency is formed The body is the cement foam material used for preventing spontaneous combustion of coal.

The cement foam material used for preventing spontaneous combustion of coal in this embodiment has a foaming ratio of 8 times, a solidification time of 38 to 40 minutes, a heat transfer coefficient of 0.061W/(m·K), and can block a gas pressure of 15Kpa. The viscosity is 4600mpa·s, the density is 400kg/m ³ , and the compressive strength is 1.95Mpa. It can be piled up to high places, and can cover and wrap both medium and high coals. It has good permeability to coal rock cracks and strong stability.

When using the cement foam material for preventing spontaneous combustion of coal according to the present invention for fire prevention in coal mines, a coal mine grouting pump is used to inject the prepared cement foam material for preventing and controlling spontaneous combustion of coal into the coal mine where there is a tendency for coal to spontaneously ignite or where air leakage needs to be blocked. In the area, the coal body is covered or the cracks are blocked to isolate oxygen and control air leakage, thereby preventing spontaneous combustion of coal.

It should be understood that the examples and embodiments described herein are only for illustration, not for limiting the present invention, and those skilled in the art can make various modifications or changes according to it. Modifications, equivalent replacements, improvements, etc., should all be included within the protection scope of the present invention.

Claims (3)

1. a cement foam material for preventing and controlling spontaneous combustion of coal is characterized in that, by weight, made from the following raw materials: Portland cement 88～91.2, sodium metaaluminate 2～2.5, calcium chloride 1.5～2 , Sodium carboxymethyl cellulose 0.3-0.5, sodium dodecyl benzene sulfonate 2-3, saponin 2-4, water 55-60. 2 . The cement foam material for preventing and controlling spontaneous combustion of coal according to claim 1 , wherein the particle size of the Portland cement is 3-40 microns. 3 . 3. the preparation method of the cement foam material for preventing and controlling spontaneous combustion of coal as claimed in claim 1 or 2, is characterized in that, comprises the following steps: (1) Mix Portland cement, sodium metaaluminate and calcium chloride evenly to form composite cement powder; (2) Mix water, sodium carboxymethyl cellulose, sodium dodecyl benzene sulfonate and saponin, and foam by high-speed stirring to form foam; (3) Under stirring conditions, the composite cement powder is added into the foam to prepare the cement foam material for preventing spontaneous combustion of coal.