Fossil coals are extremely diverse in their properties. They are determined by maternal substance, the conditions of its accumulation and the initial processes of decomposition, and secondary geological factors, under the influence of which occur subsequent processes change the coals.

The color of the coals varies from brown to black, as an exception it can be light yellow.

B l e to the coal depends on the degree of coalification. The older coals, the more they Shine, this is especially noticeable in anthracite.

I d e l l n s in th e coal depends on the quantity of mineral impurities, entering the organic mass during its accumulation, and the degree of coalification. The average specific gravity of coal of the same composition depends on the degree of coalification: brown coals have it equal to 0.8–1,24, the stone – 1,26–1,35.

T e R d o C t ü depends on the petrographic composition and degree of coalification (the higher the degree, the higher the hardness).

X p y p K o t l depends on the internal cohesion of the particles of the coal mass and from its hardness. Main ingredients are humic coals may be arranged in the following series in descending order of fragility: Fusen, windy, the McLaren, düren.

An important characteristic of coal is the content of the l e t in h and x in e o e t in. This substance, which is removed by heating coal without access of air at high temperature. Together with volatile substances moisture; the remaining solid residue called coke, which will be ash. The content of volatile matter coals are arranged in the following sequence: peat -70 %, brown coal is 45-50 %, stone coals – 35-50 %, anthracite – 5 %.

Important is x a R a C t e R to o K a. It is determined by the properties goldcrest, remaining after the removal of volatile substances. It can be in the form of powder or in the form of a sintered mass. Distinguish not caked, weakly caked, matted and, finally, sintered beads.

T h e p l o t b o R n and I with n about with b on n about with t ü coal is the amount of heat, released during complete combustion of unit weight. The calorific value is determined by completely burning the sample of coal in an atmosphere of compressed oxygen in a bomb, placed in the calorimeter. Temperature rise of water, surrounding the bomb, calculate the heat of combustion of coal, assigned to taken hanging.

In the elemental analysis of coals to determine the hydrocarbon, hydrogen, oxygen, nitrogen and sulfur, and sometimes phosphorus (table. 1.5).

There are several types of classifications of coal. They are based on the physical properties of coal, and its elementary composition. The basis of the generalized classification is based on the final product, the number of volatile substances and properties goldcrest. Depending on this, all the coals are divided into 6 types, each of them has its own name (table. 1.6).

Table 1.5

Characterization of coals

Type of fuel	The elemental composition, %	Calorific value the ability, cal/kg
C	H	O	N
Peat		6,0		2,0	4 000-5 000
Brown coal		5,2		0,8	4 500-6 200
Coal		5,0	12,2	0,8	7 000-9 000
Anthracite		2,5	2,5		9 000-9 200

Table 1.6

Generalized coal classification

Type of coal	Class	The content, %	Goldcrest properties
Cox	volatile
Dry long-flame coals		55-60	45-50	Porous, slightly caked
Fat coals are subbituminous		60-80	42-32	Fused, expanded
Fat coals		68-74	32-26	Fused, dense
Coke coal		74-82	26-18	Fused, very dense
Lean coal		82-90	18-10	Weakly caked
Anthracite		90-92	10-8	In powder form

Anthracite for coking cannot be used, as the coke is obtained in powder form.