Methods for determination of thermal properties of various materials,
including iron ore, are adequately covered in the relevant literature.
They rely, as a rule, on certain solutions to the problem of heat
conductivity without consideration of internal heat sources that occur
in the body of sample under study if the heating (cooling) process is
accompanied by various thermochemical and phase transformations, which
is typical of iron ore materials. Therefore, such methods allow
determination of only effective or apparent values of thermal
properties, which adequately reflect properties of the material only in
specific heat treatment conditions. The point is that in the presence of
internal heat sources, parameters to find substantially depend on the
heating rate and sample shape and size. This paper considers a new
technique, which allows finding (at known calculated values of heat
capacity and material density) how five thermal parameters (temperature
and heat conductivity coefficients, power of internal heat sources, as
well as effective values of heat and temperature conductivity) depend on
the heating (cooling) temperature. Improvement of methods of processing iron ore materials at elevated
temperatures in various heat aggregates requires knowledge of thermal
properties of the materials and variation of these parameters during
heat treatment in a wide temperature range. This is due to the fact that
heating of such materials is usually accompanied by development of
complex physical and chemical processes such as oxidation and reduction
of iron oxides, decomposition of carbonates, porosity and strength
change, formation of new chemical compounds, and others, many
accompanied by release or absorption of heat [1–12]. The degree of
completion of these processes depends on the temperature conditions and
composition of the material and coolant. Consideration of the effect of
these conditions on the temperature distribution in the treated layer of
material and consequently on the duration of the heat treatment it is
possible only having reliable data on the thermal constants [13]. Methods of determination of thermal properties of iron ore materials
are widely discussed in the literature [14–20]. However, all they
address the heat conductivity problem without consideration of internal
heat sources, and thus can determine only the effective values of
thermal parameters, valid for specific conditions of heating. The effect of internal heat sources on thermal properties to find can
be taken into account only by using respective solutions to the heat
conductivity problem. The below method to determine the complex of
thermal properties of iron ore materials relies on the solution to the
heat conductivity problem with internal heat sources under symmetric
heating conditions of the first kind, which is valid for objects of
simplest shape (infinite plate, infinite cylinder, ball).