Coal annihilate is a kind of black mudstone with high ash content, low carbon content and low heat. It is accompanied by coal seams in the process of coal formation and removed in the process of coal mine production. Compared with coal, the ash content is more than 40% ~ 50%, the carbon content is 20% ~ 30%, and the heat is 800 ~ 1500kg / kg, sometimes as high as 1500 ~ 3000kg / kg. Coal research stone contains silicon, lead, calcium, magnesium and some rare elements. It is widely used, mainly including: (1) boiling boiler fuel; (2) Manufacture of cement or concrete products; (3) Manufacturing building materials and coal gangue bricks; (4) Manufacturing gas; (5) Extraction of chemical products; (6) Manufacturing fertilizer; (7) For power generation.

Comprehensive utilization of coal gangue.
（1） Coal gangue brick.
Including the production of sintered brick and internal fuel from coal gangue.
Coal gangue brick takes coal gangue as the main raw material, which generally accounts for more than 80% of the blank quality. Some take coal gangue as the raw material, and some have less admixture, although there is less clay. Coal gangue is made by crushing, grinding, stirring, pressing, forming, drying and baking. There is basically no need to add fuel during baking. Mud and carbon coal gangue.
The stone is soft and easy to break. It is an ideal raw material for the production of coal gangue brick. The calorific value of coal gangue is required to be 2100 ~ 4200kg / kg. If it is too low, coal needs to be added. If it is too high, it is easy to over fire the brick. More than 75% of the particles need to be crushed to less than LMM. The plasticity index of the blank pressed by coal gangue powder shall be between 7-17.
The moisture content is generally 15% - 20%. The compressive strength of coal gangue bricks produced by many brick factories is generally 4.80 ~ 1:4.71mpa, and the flexural strength is 2.94 ~ 4.90mpa, which is higher than that of ordinary clay bricks. The production process and process of coal gangue inner fuel brick are basically the same as that of coal as inner fuel, only the crushing process of coal grinding stone needs to be added.
(2) Coal gangue produces light aggregate.
Coal grinding stone suitable for firing lightweight aggregate is mainly carbon shale and coal gangue discharged from concentrator. Although the carbon content of coal gangue should not be too large, it should be less than 13%. There are two firing methods: balling method and non balling method. The pelletizing method is to crush the coal gangue, grind it into spherical particles, and then bake it. Return the spherical particles to the rotary kiln,
After preheating, it enters the decarburization section, the carbon in the ball starts to burn, then enters the expansion section, and then cools and sieves out of the factory. The loose amount is generally about 1000kg / m3. The non pelletizing method is to break the coal gangue to a certain particle size and bake it directly. The coal gangue is crushed to 5 ~ lomm and laid on the grate of the sintering machine. When the coal gangue is ignited.
After that, the temperature in the middle of the material layer can reach 1200C and the temperature at the bottom is less than 350C. The unburned gangue is returned to sintering after screening and separation. The sintered lightweight aggregate leaves the factory after being cooled, crushed and screened by water spray. Its weight is generally about 800kg / m3.
(=) coal gangue produces hollow blocks.
Coal gangue hollow block is a wall material made of spontaneous combustion or artificial calcined coal gangue as aggregate, ground lime and stone as cement, rotary molding and steam curing. The product label can reach No. 200.
(4) Coal gangue is used as raw fuel to produce cement.
The chemical composition of coal research stone is similar to that of clay, which can release a certain amount of heat. Using it to replace clay and some fuels to produce ordinary cement can improve the quality of clinker. This is because the activation energy of coal gangue proportioning is much lower than that of clay proportioning. The combustibles in coal gangue can improve the pre burning temperature of raw materials.
It is also conducive to the melting and formation of silicate and other minerals; In addition, the raw material surface of coal gangue can be very high, and acid oxides such as silicon and aluminum can easily absorb calcium oxide, which can accelerate the formation of minerals such as calcium silicate. The production process of coal gangue as cement raw fuel is basically the same as that of ordinary cement. Raw materials and fuels shall be grinded in proportion.
Fine raw materials are burned and partially melted to obtain clinker with calcium silicate as the main component, and then an appropriate amount of limestone and mixed materials are added to grind into fine powder to make cement.
(5) Coal gangue is used as cement mixture.
Coal gangue has certain activity after spontaneous combustion or artificial calcination. It can be mixed with cement as active mixing material, configured in proportion with clinker and stone, and then ground in cement. The content of coal gangue depends on the type and label of cement. 325-425 ordinary silicate brine can be made by adding 15% coal gangue into cement clinker.
Mud; When the content is more than 20%, it is pozzolanic Portland cement according to national regulations. When coal gangue is used as mixed material, the combustion loss shall be controlled ≤ 5%, s03s3%. Pozzolanic test must be qualified, and the compressive strength ratio of cement sand shall be ≥ 62%.
(6) Coal gangue is used as road construction and filler.
Coal gangue is a good road building material. It has good weather erosion resistance and can reduce the cost of road construction.