the furnaces, while the coal lumps reduce the burning
rate. Regulating the porosity of the obtained coal
briquettes is one of the important tasks of increasing
their combustibility and environmental cleanliness of
the atmosphere.
We should consider the scientific basis of the
formation of the structure of coal briquettes with
binders and additives as one of the types of bonding of
dispersible solid materials using binders. The mixture
forms the basis of the formation of the interconnection
of individual contact particles in the structure, which
are self-regulating and self-regulating processes, and
determine the attachment process. As the initial stage
of the bonding process, adhesion is associated with the
formation of an adhesive film on the surface of a solid
body (substrate). Adhesion is characterized by the
viscous liquid state of the binder. Further processes
lead to an increase in the maximum strength of the
binder. As a result, separated solid particles coated
with a binder are attached in the form of briquettes
(Petrova, Latyshev, & Burenina, 2007).
In this process, the diffusion coefficient is the
difference between the adhesion energy of the binder
to the substrate and the adhesion of the binder. It
serves as a measure to evaluate the wettability of the
binder, which describes the relationship between the
structure of the binder and the orientation of its
molecules on the surface of the substrate. Substances
containing binding and multipolar groups have a high
scattering coefficient. With higher values, the binder
is sufficiently wetted. If its value is negative, it does
not spread to the solid body and wraps in the form of
a lens (Aleksandrova, Rasskazova, & Prokhorov,
2012; Semenov, Podolskaya, Buzaeva, & Klimov,
2009).
The granulometric structural value is determined
by the total contact surface of the grains, the number
and size of the voids in the structural frame of the
briquettes, the content of sharp-cornered grains, the
relief and impact of the hard surface. The principle of
choosing a mixture of coal particles of different sizes
is to create a structural composition that meets the
standard requirements (Podolskaya, Buzaeva, &
Klimov, 2011; Chiari, 1990) .
Small grains are more angular than large ones, and
the heat content of hydration is about 4 times higher
than that of the latter. The addition of large grains to
briquettes (more than 6 mm) negatively affects the
strength of coal briquettes, that is, new surfaces that
are not covered with binder appear. The porosity of the
structure significantly affects the packing density of
coal briquettes. No matter how carefully the solid
grains are packed into briquettes, there will always be
holes between them. The number and size of voids
affect the durability of briquettes. Briquettes made of
fine coal particles have small holes and are mostly
filled with binder. If there are few defects in the form
of voids, the strength of coal briquettes is high.
Briquettes consisting of large grains will have many
defects. The adhesive layer will not be enough to fill
the gaps in them. Therefore, these briquettes are
considered to have low strength. To increase the
strength, it is recommended to add dust-like coal
particles to the briquette mixture, which easily
penetrate into the voids. The unevenness and
unevenness of the material has a positive effect on the
mechanical fastening of the binder and increases the
strength of the briquettes. If the composition of the
sieve is homogeneous, the strength of the briquettes
decreases. A homogeneous mixture does not allow to
ensure compaction density. Grains accumulate in the
briquette with a significant number of voids [6; 7;]. To
increase the strength, it is recommended to add dust-
like coal particles to the briquette mixture, which
easily penetrate into the voids. The unevenness and
unevenness of the material has a positive effect on the
mechanical fastening of the binder and increases the
strength of the briquettes. If the composition of the
sieve is homogeneous, the strength of the briquettes
decreases. A homogeneous mixture does not allow to
ensure compaction density. Grains accumulate in the
briquette with a significant number of voids (Gos,
2021; Salikhanova, Abdurahimov, & Jumayeva,
2020). To increase the strength, it is recommended to
add dust-like coal particles to the briquette mixture,
which easily penetrate into the voids. The unevenness
and unevenness of the material has a positive effect on
the mechanical fastening of the binder and increases
the strength of the briquettes. If the composition of the
sieve is homogeneous, the strength of the briquettes
decreases. A homogeneous mixture does not allow to
ensure compaction density. Grains accumulate in the
briquette with a significant number of voids (Gos,
2021; Salikhanova, Abdurahimov, & Jumayeva,
2020);]. Grains accumulate in the briquette with a
significant number of voids (Gos, 2021; Salikhanova,
Abdurahimov, & Jumayeva, 2020). Grains
accumulate in the briquette with a significant number
of voids (Gos, 2021; Salikhanova, Abdurahimov, &
Jumayeva, 2020).
In nature, there are several types of coals, formed
underground at different times and conditions from
different types of plant and animal sources.
Therefore, coals mined in opposite continents and
regions of our planet have significant differences in
composition and physical and chemical properties.
Their composition and properties should be taken into