Abstract

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).

中文翻译：

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铁矿石材料热性能测定技术

摘要

相关文献充分地涵盖了用于确定包括铁矿石在内的各种材料的热性能的方法。通常，如果加热（冷却）过程伴随着各种热化学和相变（通常是典型的），它们就依赖于导热性问题的某些解决方案，而不考虑被研究样品体内出现的内部热源。铁矿石材料。因此，这种方法仅允许确定热性能的有效值或表观值，仅在特定的热处理条件下才足以充分反映材料的性能。关键在于存在内部热源时，要找到的参数基本上取决于加热速率以及样品的形状和大小。本文考虑了一种新技术，

改进在各种热聚集体中在高温下处理铁矿石材料的方法需要了解材料的热特性以及在宽温度范围内的热处理过程中这些参数的变化。这是由于以下事实：加热此类材料通常伴随着复杂的物理和化学过程的发展，例如氧化铁的氧化和还原，碳酸盐的分解，孔隙率和强度的变化，新化学化合物的形成，等等。伴随着热量的释放或吸收[1-12]。这些过程的完成程度取决于温度条件以及材料和冷却剂的成分。

确定铁矿石材料热性能的方法在文献中已广泛讨论[14-20]。但是，它们都解决了热导率问题，而没有考虑内部热源，因此只能确定对特定加热条件有效的热参数有效值。

内部热源对发现的热性能的影响只能通过使用热导率问题的相应解决方案来考虑。以下确定铁矿石材料热特性复杂度的方法取决于在第一类对称加热条件下内部热源的导热系数问题的解决方案，该方法适用于形状最简单的物体（无限板，无限圆柱体） ， 球）。