Introduction to comprehensive utilization of coal gangue in China

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Summary and introduction of comprehensive utilization of coal gangue in China

With the exploitation and separation of coal resources, a large number of coal gangue has been produced in the concentrator. Due to the existence of harmful substances in coal gangue, it will cause serious pollution to the environment and cause great harm to human health. Therefore, it is necessary to deal with it timely and effectively in order to reduce its harm. Therefore, the comprehensive utilization of coal gangue has important significance.

 gangue

Comprehensive utilization of coal gangue in China

1. Coal gangue power generation and heating

Coal gangue power generation and heating is an important way to use coal gangue in China.

The key of coal gangue power generation is the combustion and utilization of coal gangue. Coal gangue power generation not only provides new energy for coal mine production, but also brings huge economic and social benefits. Now the fluidized bed is used, which uses fluidized bed boiler and circulating fluidized bed boiler to burn all kinds of inferior fuel and generate various nitrogen oxides and sulfides.

Coal gangue is used as fuel for power generation and heat supply. Generally, the calorific value of coal gangue is more than 1200 kJ / kg, which can be divided into two types: one is full coal gangue power generation; the other is coal gangue and slime mixed power generation.

In China, the installed capacity of coal gangue and slime power generation has reached 28 million KW, annual utilization of coal gangue is 140 million tons, and there are more than 400 comprehensive utilization power generation enterprises, which are mainly distributed in important coal production areas, with annual power generation capacity of 160 billion kw · h, equivalent to reducing 42 million tons of raw coal mining. Coal gangue power generation and heating is an important way to use coal gangue in China.

2. Making bricks from coal gangue

In our country, most of the clay rock gangue can be used to produce sintered brick. Generally, the whole internal combustion roasting is used, that is, the heat energy provided by the coal gangue's own heat capacity is used to complete the drying and roasting process, and no additional fuel is needed. About 1t standard coal can be saved by gangue brick per ten thousand standard blocks compared with clay brick. Coal gangue brick is mainly made of coal gangue, which accounts for more than 80% of the blank. After crushing, grinding, mixing, pressing, forming, drying and roasting, it is made into gangue brick. At present, the varieties of gangue brick include solid brick, porous bearing brick, hollow brick, etc. The production process of using coal gangue as internal fuel for brick making is basically the same as that using coal as internal fuel, and only the coal gangue crushing process needs to be added.

3. Cement production

The composition of coal gangue is complex, mainly including oxides of silicon, calcium, aluminum, iron, magnesium and some rare metals. It is similar to clay in composition and can be used to replace acid oxides. Coal gangue has been widely used in cement industry and its level is relatively mature. It is often used as raw material for cement production. As cement production It is also used to produce special cement, produce no clinker and less clinker.

4. Preparation of ceramsite from coal gangue

The coal gangue that meets the requirements of burning expansion is crushed (particle size less than 10 mm), preheated (temperature 250 ℃), burning expansion (temperature 1100-1200 ℃), cooling and grading, and then made into coal gangue ceramsite. Coal gangue ceramsite has the properties of heat resistance, frost resistance, acid and alkali resistance, corrosion resistance and low coefficient of thermal expansion. It can be widely used as pavement materials of expressways and airport runways, and can also be used as heat preservation, sound insulation, heat insulation wall materials, heavy oil dehydration and industrial water filtering materials.

5. It is used as the filling material for roadway protection

Gangue filling material is a kind of mixed filling material, which is made of cement as cementation material, coal gangue powder as aggregate and additives.

6. Subsidence for reclamation

When the coal gangue is used as filling material to fill the goaf, the method of layered filling should be adopted. Each layer should be rolled separately and lime water should be sprayed separately. In this way, better foundation stability and bearing capacity can be obtained

7. As road building materials

Coal gangue is cemented with water hard gel material or asphalt to seal its surface, so that it can be stable and bear heavy pressure even after being soaked in water or frozen. It can be used as the base, subbase and railway subgrade of highway.

In a word, the comprehensive utilization of coal gangue mainly includes coal gangue power generation, production of building materials, landfill, road construction, filling goaf, etc. at present, domestic power generation utilization accounts for 10% ~ 40% of the total treatment capacity of coal gangue, accounting for 21% of the total generated coal gangue; landfill, road construction and filling goaf are the main harmless treatment methods, accounting for 50% ~ 80% of the total treatment capacity, which is about the total production The treatment capacity of building materials is low, accounting for only 10% - 15% of the total treatment capacity, less than 8% of the total production; more than 35% of the coal gangue is still stored.

Existing problems and suggestions for improvement

1. The utilization rate of coal gangue resource is low. It is suggested to carry out classified management and efficient utilization. Through the classification management of coal gangue, the repeated construction of power generation and brick and tile making projects can be avoided, which can effectively separate the main components of coal gangue, and make the utilization of coal gangue resources scientific, orderly and sustainable.

2. The utilization of coal gangue is poor. It is suggested to develop a new mode and develop circular economy. For the existing coal gangue dump in the coal mine area, we should develop the ecological economic model with regional characteristics such as "landfill land reclamation ecological agriculture ecological tourism", and reduce and harmless coal gangue.

3. The regional imbalance of comprehensive utilization of coal gangue is serious. It is suggested to increase the flexibility of relevant preferential policies.

To sum up, the serious harm of coal gangue has been recognized, and the comprehensive utilization of coal gangue is urgent. The coal gangue industry should be developed in an all-round way with reasonable layout and equipment.

Our company can provide the coal gangue processing needs Crushing equipment drying equipment Coal gangue recycling equipment can be greatly improved.

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