CN105152601B - A kind of preparation method of bastard coal ground mass mine cemented filling material - Google Patents

Abstract

The invention discloses a kind of preparation method of bastard coal ground mass mine cemented filling material, belong to filling in mine Material Field.The present invention ejects the potential gelation activity of gangue by complex excitation mode, and part substitution cement serves as the binder materials of mine cemented filling, is then hybridly prepared into mine cemented filling material with fine grain gangue.The gangue base cemented filling material technique prepared using inventive formulation is simple, realize the vast scale volume and filler of colliery powder and cement have preferable mechanical property, stable transportation performance, do not isolate, not bleeding, application of the gangue in filling in mine is widened, reduce filling in mine cost, improve material transportation performance, the purpose effectively using gangue is reached simultaneously, promotes advancing for filling in mine.

Description

A preparation method of coal gangue-based mine cemented filling material

technical field

The invention relates to a preparation method of a coal gangue-based mine cemented filling material, which belongs to the field of mine filling materials.

Background technique

Coal gangue is the solid waste discharged during coal mining and washing. It is one of the largest industrial solid wastes in my country. It has accumulated nearly 4 billion tons, occupies more than 10,000 hectares of land, and still costs 100 million The number of tons or so has increased dramatically year by year. A large amount of coal gangue not only occupies arable land, but also easily weathers and spontaneously combusts, causing air, soil and water pollution, and even causing serious geological disasters, which has extremely bad effects on the ecological environment and social environment. Therefore, the disposal and effective utilization of coal gangue has become an urgent problem to be solved.

At present, the utilization of coal gangue mainly includes brick making, power generation, etc., using the calorific value of coal gangue itself, and directly using it after crushing to make blocks, concrete aggregates, backfilling mine goafs or paving materials, etc. , and the similar properties of coal gangue to clay are also used to replace part or all of the clay to produce cement. However, due to the high performance requirements of cement surface quality and strength in ground construction projects, when coal gangue is used for firing cement It is difficult to meet the requirements of construction projects. The utilization rate of coal gangue is still less than 20%.

With the rapid development of my country's coal industry, the area of gobs continues to expand, and the problems of surface subsidence and "three-down" coal pressure become more and more prominent. The advantages of filling mining technology in preventing large-scale surface subsidence, liberating "three-down" coal pressing, improving resource recovery rate, and solving the problem of coal gangue stacking on the ground are becoming more and more prominent. At present, the main filling material is Portland cement as the cementitious material. , using crushed coal gangue as aggregate is not only expensive, but also has unstable conveying performance, which seriously restricts the development of coal mine filling. Therefore, it is necessary to develop a new cementitious material to replace cement to promote cemented filling mining. technology development.

Compared with ground construction projects, mine filling has lower requirements for filling materials. According to different roof conditions, the strength of the filling body is only required to be 0-8MPa, and generally 0.5-4MPa can meet the requirements. SiO ₂ and Al ₂ O ₃ in coal gangue are potential gelling active components, which can stimulate their gelling properties and partially replace cement as the gelling material in cemented filling materials, thereby reducing the amount of cement and reducing costs. At the same time, it solves the problem of coal gangue discharge, promotes the application and promotion of coal mine cemented filling technology, and realizes the green and sustainable development of the coal industry.

Contents of the invention

The present invention aims to provide a preparation method of coal gangue-based cemented filling material for mines. The potential gelling activity of coal gangue is stimulated through a composite excitation method, and part of the cement is used as the cemented material for mine cemented filling, and then mixed with fine-grained coal Gangue is mixed and formulated into mine cemented filling materials, which reduces the cost of filling materials, improves material conveying performance, and achieves the purpose of effectively utilizing coal gangue.

A method for preparing coal gangue-based mine cemented filling material provided by the present invention comprises the following steps:

(1) First, crush the large pieces of coal gangue so that the particle size of the crushed particles is distributed in the range of 0-5 mm, and set aside;

The chemical composition of the coal gangue is: SiO ₂ : 35%-57%, Al ₂ O ₃ : 16%-25%, and SiO ₂ and Al ₂ O ₃ are latent gelling active substances. And does not contain radioactive elements.

(2) Grinding the coal gangue crushed in step (1) on a ball mill for 45-60 minutes, and sieving with 200-mesh and 300-mesh standard sieves to obtain coal gangue powder with a particle size of less than 300 mesh;

(3) Put the coal gangue powder obtained in step (2) in an industrial furnace, heat up to a calcination temperature of 700-750°C, and keep it warm after the calcination is completed, and the holding time is 2-2.5 hours;

(4) taking out the calcined coal gangue powder in step (3) and quenching;

The rapid cooling is to directly take the calcined coal gangue powder out of the industrial furnace and put it in the air to cool to room temperature.

(5) Add a chemical activator to the coal gangue powder that has been cooled to room temperature in step (4) and pre-mix for 30 seconds.

The chemical activators are Al ₂ (SO ₄ ) ₃ , NaOH, CaSO ₄ ·2H ₂ O, all of which are analytically pure chemical reagents. Wherein the mass proportioning of each activator and coal gangue is respectively:

NaOH: 1~5:100;

Al ₂ (SO4) ₃ : 5~10:100;

CaSO ₄ 2H ₂ O: 1~5:100;

(6) Mix the cement with the gangue powder in step (5) and stir for 120s. After fully mixing, the cementitious material for mine cementation filling is obtained, wherein the mass ratio of gangue powder and cement is:

Coal gangue powder: 50%-70%;

Cement: 30%-50%;

(7) After premixing the fine-grained coal gangue in step (1) with the cementitious material in step (6) for 30 seconds, add water and stir evenly to make a mine cemented filling material, in which the fine-grained coal gangue is mixed with the cementitious material The mass ratio of materials is:

Fine-grained coal gangue: 70%-80%;

Cementitious material: 20%-30%;

The mass ratio of water to gelling material is: 0.4-0.8:1.

Further, the cement in the step (6) is 42.5 ^# ordinary Portland cement.

In the present invention, coal gangue is subjected to compound excitation of thermal excitation, mechanical excitation and chemical excitation to form coal gangue powder, and then mixed with cement to form a cementitious material.

Beneficial effects of the present invention:

(1) Improve the status quo of low added value of coal gangue, low economic benefits, and lagging utilization technology, realize large-scale and high value-added utilization of coal gangue, use coal gangue more efficiently and rationally, and solve the problem of disorder on the ground of coal gangue Ecological and social environmental problems caused by stacking.

(2) The coal gangue-based cemented filling material prepared by the formula of the present invention has a simple process, realizes a large proportion of coal gangue powder and cement, and the filling material has good mechanical properties, stable transportation performance, no segregation, and no leakage Water, broaden the application of coal gangue in mine filling, reduce the cost of mine filling, and promote the development of mine filling.

(3) Grinding coal gangue and mixing it into cement not only improves the gelling performance of the filling body, but also the addition of ultra-fine coal gangue powder greatly improves the pumping performance of the filling material.

(4) By adjusting the proportion of excited coal gangue powder, cement, chemical activator, and fine-grained coal gangue, it is possible to prepare a filling body that meets various roof conditions, and then popularize and apply it to different coal mines to control roof underfilling. sink, reduce surface subsidence, and liberate the "three under" pressure coal to promote the green and sustainable development of coal.

detailed description

The present invention is further illustrated by the following examples, but not limited to the following examples.

Example 1:

(1) First, crush and screen large pieces of coal gangue with a jaw crusher, and control the particle size of coal gangue within the range of 0 to 5mm.

The effective chemical composition of the gangue is: SiO ₂ : 35.46%, Al ₂ O ₃ : 16.11%

(2) Accurately weigh 18kg of 0-5mm coal gangue and grind it in a ball mill for 45 minutes, and then sieve it with 200-mesh and 300-mesh standard sieves to obtain coal gangue powder with a particle size of less than 300 mesh for use.

(3) Put all 18kg of coal gangue powder in step (2) into an industrial furnace, heat up to 750°C for calcination, and calcine at a constant temperature of 750°C for 2 hours.

(4) The calcined coal gangue in step (3) is taken out and rapidly cooled for later use.

(5) Add 1.62 kg of Al ₂ (SO ₄ ) ₃ , 0.54 kg of NaOH, and 0.84 kg of CaSO ₄ ·2H ₂ O powdered analytically pure chemical reagents to the gangue powder in step (4), and pre- Mix for 30s to make the components evenly mixed.

(6) Accurately weigh 9kg of 42.5 ^# ordinary portland cement and mix and stir the gangue sample in step (5) for 120s to make it fully mixed.

(7) Take 70kg of coal gangue with a fine particle size of 0-5mm in step (1) and premix it with the cementitious material in step (6) for 30 seconds, then accurately weigh 21kg of tap water into the mixed material and stir for 120 seconds. That is, the mine cemented filling material is obtained. Test the slump, expansion and compressive strength.

Table 1

Example 2:

(1) First, crush and screen large pieces of coal gangue with a jaw crusher, and control the particle size of coal gangue within the range of 0 to 5 mm.

The effective chemical composition of the gangue is: SiO ₂ : 50.33%, Al ₂ O ₃ : 23.46%

(2) Accurately weigh 15kg of 0-5mm coal gangue and grind it in a ball mill for 60 minutes, and then sieve it with 200-mesh and 300-mesh standard sieves to obtain coal gangue powder with a particle size of less than 300 mesh for use.

(3) Put all 15kg of coal gangue powder in step (2) into an industrial furnace, heat up to 700°C for calcination, and calcine at a constant temperature of 700°C for 2.5 hours.

(4) The calcined coal gangue in step (3) is taken out and rapidly cooled for later use.

(5) Add 1.20 kg of Al ₂ (SO ₄ ) ₃ , 0.60 kg of NaOH, and 0.45 kg of CaSO ₄ ·2H ₂ O powdered analytically pure chemical reagents to the gangue powder in step (4), and pre- Mix for 30s to make the components evenly mixed.

(6) Accurately weigh 10kg of 42.5 ^# ordinary portland cement and mix it with the gangue sample in step (5) for 120s to make it fully mixed.

(7) Take 75 kg of coal gangue with a fine particle size of 0-5 mm in step (1) and premix it with the cementitious material in step (6) for 30 seconds, then accurately weigh 17.5 kg of tap water, add it to the mixed material and stir for 120 seconds. That is, the mine cemented filling material is obtained. Test the slump, expansion and compressive strength.

Table 2

In order to ensure good pipeline transportation performance of the filling material and good mechanical strength of the filling body, it is required that the slump of the filling material should not be less than 180mm, and the strength should be 0-8MPa. As can be seen from Table 1 and Table 2, the slump of the mine cemented filling material prepared by the present invention is greater than 180mm, which has well met the requirements of the mine filling pipeline for material performance, and the 7-day compressive strength has exceeded 8MPa, which is very good It meets the requirements of mine filling for the strength of the filling body. In summary, the mine cemented filling material configured by the present invention has good conveying performance and mechanical properties, and can be popularized and applied to different coal mines to control roof subsidence, reduce surface subsidence, liberate "three-down" coal pressing, and promote the green and sustainable development of coal .

Claims (3)

1. a kind of preparation method of bastard coal ground mass mine cemented filling material, it is characterised in that：Comprise the following steps：

（1）Bulk gangue is crushed first, make it is broken after particle size distribution 0~5mm scope, it is standby；

The chemical composition of the gangue is：SiO₂：35%-57%、Al₂O₃：16%-25%；Wherein SiO₂、Al₂O₃For potential gelling Active component, and without radioactive element；

（2）By step（1）In crush after gangue on ball mill grinding 45min-60min, and with 200 mesh, 300 targets standard Sieved, obtain the gangue powder that particle diameter is less than 300 mesh；

（3）By step（2）In obtained gangue powder be placed in industrial furnace, be warming up to 700 ~ 750 DEG C of calcining heat, calcined It is incubated into rear, soaking time is 2 ~ 2.5 hours；

（4）By step（3）In calcining coal gangue powder take out chilling；

（5）To step（4）In have cooled in the gangue powder of room temperature and add chemical activator and premix 30s；

Described chemical activator is Al₂(SO₄)₃, NaOH and CaSO₄·2H₂O；The quality of the chemical activator and gangue Match and be：

NaOH：1~5∶100；

Al₂(SO₄)₃：5~10∶100；

CaSO₄·2H₂O：1~5∶100；

（6）By cement and step（5）In gangue powder be mixed and stirred for 120s, described mine is obtained after being sufficiently mixed The binder materials of consolidated fill, the quality proportioning of wherein gangue powder and cement is：

Gangue powder：50%-70%；

Cement：30%-50%；

（7）Take step（1）In 0~5mm fine grain gangue and step（6）In binder materials premix 30s after, add water stir Mix and mine cemented filling material uniformly is made；The quality proportioning of wherein fine grain gangue and binder materials is：

Fine grain gangue：70%-80%；

Binder materials：20%-30%；

The quality proportioning of water and binder materials is：0.4-0.8:1.

2. the preparation method of bastard coal ground mass mine cemented filling material according to claim 1, it is characterised in that：Described Chilling is directly to take out to put from industrial furnace by calcining coal gangue powder to be cooled to room temperature in atmosphere.

3. the preparation method of bastard coal ground mass mine cemented filling material according to claim 1, it is characterised in that：The step Suddenly（6）In cement be 42.5# Portland cements.