Characteristics of Infrared Radiation in the Failure of Phosphate Rock at Different Loading Rates

Chengcheng Gao,Yongxiong Lu,Xiaoshuai Liang,Guangliang Feng,Manqing Lin,Dianji Zhang

doi:10.3389/feart.2021.812661

Abstract

Safe and effective mining of phosphate rock plays an important role in the sustainable development of phosphorus resources. The mechanical properties and failure process of phosphate rock under different mining rates remain unclear, further restricting the safe and efficient mining of phosphate rock. In this paper, infrared radiation and uniaxial compression tests of phosphate rock under different loading rates, e.g., 0.0005, 0.001, 0.005, and 0.01 mm/s, were conducted to investigate the failure process of phosphate rock. Energy evolution and infrared radiation characteristics of the phosphate rock damage process were analyzed using nondestructive, real-time, and noncontact infrared thermal imaging technology. The results show that the higher the loading rate of phosphate rock, the more obvious the high-temperature zone and high-temperature point of phosphate rock in the loading process. At failure, the friction and slippage between internal cracks are intense, showing that the infrared radiation temperature difference increases with the increase of loading rate. As loading rate increases, the energy release time of phosphate rock before damage is reduced, resulting in more energy stored in the rock as evinced by its infrared radiation characteristics, finally resulting in greater damage. The increase of loading rate reduces the dissipation energy of phosphate rock before failure so that more energy remains in the rock mass through the weak surface of the grain boundary. The results of this work will be helpful in enhancing theoretical support for prevention and control of dynamic disasters in phosphate mines.

Highlights

Phosphate rock, as a nonrenewable resource (Vaccari and Strigul, 2011), is an important nonmetallic mineral resource, mainly distributed in Africa, North America, South America, Asia, and the Middle East
The specimen is crushed into multiple blocks of different sizes at failure, which cannot maintain its integrity: the degree of crushing of phosphate rock increases with the increase of loading rate, and many particles are crushed at a higher loading rate
The result indicated that the change of loading rate affects the failure mode of phosphate rock specimens

Summary

Introduction

As a nonrenewable resource (Vaccari and Strigul, 2011), is an important nonmetallic mineral resource, mainly distributed in Africa, North America, South America, Asia, and the Middle East. Global phosphate rock production driven by demand has been increased year on year. Based on the current global phosphate rock production capacity and the amount of retained resources, the available period of resources is a further 99 years. Due to insufficient rich ore reserves in China and the gradual depletion of shallow phosphate resources, deep phosphate must be mined. With the increase of mining depth, rockbursts in deep phosphate rock frequently occur, which seriously threaten the safety of underground mining. The identification of rockburst precursors is of great significance to the safe mining of phosphorus resources and deep engineering (Guang-Liang et al, 2015a; Guang-Liang et al, 2019a; Guang-Liang et al, 2021)

Methods

Results

Conclusion