Study on heat transfer behavior and thermal breakage characteristic of the charge in ball mills

Tongqing Li,Zixin Yin,Guiyi Wu

doi:10.1177/1687814021994964

Tongqing Li, Zixin Yin + Show 1 more

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https://doi.org/10.1177/1687814021994964

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Abstract

Ball mill is the widely used comminution device for the size reduction of iron ore particles, yet the underlying mechanisms of heat transfer and thermal breakage inside the mills heretofore are not deeply understood. Therefore, the Discrete element method was carried out to study the effect of operating parameters on charge temperature, and the batch grinding experiments of iron ores were conducted to verify the heating temperatures using a laboratory ball mill. Results show that increasing mill speed will result in the charge temperature increasing initially and then decreasing. The temperature fields of the charge and load behavior remain approximately the same for the different ball filling. The main findings of this study are that the heating temperature can contribute to enhancing the breakage behavior of iron ore particles, and correspondingly the optimal feed sizes for different heating temperatures are determined to be 2.48 mm, 2.63 mm, 2.78 mm, and 3.59 mm, respectively.

Highlights

Ball mill is an energy-intensive device for grinding and breaking iron ore particles, which is extensively used in mineral, cement, chemical, and other industries.[1,2,3,4] In the field of mineral processing, a portion of the energy is converted into heat that will raise the milling temperature and breakage characteristics of iron ore will be changed
Little attention has been given to the study of heat transfer and thermal breakage in ball mills, whether the breakage kinetics of material is related to the thermal behavior has not been studied
To understand the mechanism of heat transfer and improve the grinding efficiency, the heat transfer model should be established and the thermal breakage experiments should be conducted in detail

Summary

Introduction

Ball mill is an energy-intensive device for grinding and breaking iron ore particles, which is extensively used in mineral, cement, chemical, and other industries.[1,2,3,4] In the field of mineral processing, a portion of the energy is converted into heat that will raise the milling temperature and breakage characteristics of iron ore will be changed . Gui and Fan[17] used DEM simulation with a thermal conduction model to investigate the effect of rotational speed and wave number on heat transfer. The above literature mainly investigates the heat transfer behavior of high-temperature rotation body to granular material All of these provide an insight into the heat transfer phenomenon. A laboratory ball mill was applied to study the effect of heating temperature on the breakage characteristics of iron ore These results explore the relationship between charge temperature and operating parameters and can apply in other particle systems that are sensitive to temperature variation. To quantitatively describe the discrete heat transfer characteristics of charge in ball mills, this work focused on charge thermal conduction behavior and collision heat.

Material and method

Findings

Conclusions