img

Wechat

Adv. Search

Gold Science and Technology ›› 2020, Vol. 28 ›› Issue (4): 521-530.doi: 10.11872/j.issn.1005-2518.2020.04.016

• Mining Technology and Mine Management • Previous Articles     Next Articles

Experimental Study on Mechanical Impact Breaking Rock with Microwave Radiation

Biwei HU(),Tubing YIN(),Xibing LI   

  1. School of Resources and Safety Engineering,Central South University,Changsha 410083,Hunan,China
  • Received:2019-12-24 Revised:2020-03-25 Online:2020-08-31 Published:2020-08-27
  • Contact: Tubing YIN E-mail:406281952@qq.com;tubing_yin@mail.csu.edu.cn

Abstract:

In industrial production,dynamic load rock breaking equipment is widely used in metal and non-metal mines,such as drill,downhole drill and cable drill.Mechanical rock breaking is often faced with such problems as low crushing efficiency,poor crushing effect and expensive equipment.Therefore,it is necessary to find an efficient,simple and safe method to break the rock.Microwave-assisted percussive rock breaking is an important means to break hard rock quickly.It is of great theoretical and practical significance to study the impact resistance of rock by microwave radiation.In this paper,an industrial microwave oven was used to test the radiation of sandstone with different power and time.The wave velocity of sandstone before and after radiation were measured and the porosity of rock before and after radiation were measured by nuclear magnetic resonance equipment.Then,the dynamic compressive mechanical strength of rock was tested by SHPB method,and the rock failure process and characteristics were recorded by high-speed camera.The results show that under the microwave radiation,the sandstone heating speed is very fast.Under the radiation power of 5 kW,the sandstone heating rate reaches 1.29 ℃/s,and under the condition of 3 kW,it reaches 1.04 ℃/s.After the microwave radiation,the wave velocity of sandstone decrease continuously and the porosity increase continuously.After 5 kW radiation for 4 min,the wave velocity decreases by 34% and the porosity increases by nearly 70%.The dynamic compressive strength of sandstone is also continuously reduced,and after 5 kW and 3 kW radiation for 4 min,it decreases by 60.4 MPa and 44 MPa respectively.Under the action of impact stress,rock shows radial failure modes and axial failure modes.The results show that microwave radiation can rapidly heat up sandstone.Because of the thermal stress,cracks are generated inside the sample then spread,which makes the wave velocity decrease and the porosity increase and the dynamic compressive strength decrease drastically.

Key words: picrowave irradiation, dynamic compressive strength, P-wave velocity, porosity, nuclear magnetic resonance

CLC Number: 

  • TD05

Table 1

Basic mechanical parameters of sandstone"

参数名称参数值参数名称参数值
弹性模量E/GPa14.76密度ρ/ (g·cm-3)2.56
泊松比υ0.36单轴抗压强度σ/MPa84.57
纵波波速V/(m·s-13 137.54

Fig.1

Optical flakes and XRD patterns of sandstone samples"

Table 2

Sandstone mineral composition and its microwave absorbing ability"

矿物类型矿物质量百分比/%矿物吸波能力粒径/mm
石英41.72非常弱0.06~0.40
长石34.490.05~0.40

蒙脱石

滑石

9.35

6.18

0.10~0.40

0.02~0.06

方解石4.730.01~0.03
赤铁矿5.53很强0.20~0.40

Fig.2

Flow chart of experimental research"

Fig.3

Rock temperature rise curve and rock thermal fracture"

Fig.4

Wave velocity changes before and after microwave irradiation of sandstone"

Fig.5

Nuclear magnetic resonance T2 curves"

Fig.6

Porosity changes before and after microwave irradiation of sandstone"

Fig.7

Dynamic mechanical stress-strain curves"

Fig.8

Relationship between dynamic compression intensity and radiation time"

Fig.9

High-speed camera image of impact damage process"

1 卢高明,李元辉,Hassani F,等.微波辅助机械破岩试验和理论研究进展[J].岩土工程学报,2016,38(8):1497-1506.
Lu Gaoming,Li Yuanhui,Hassani F,et al.Review of theoretical and experimental studies on mechanical rock fragmentationusing microwave-assisted approach[J].Chinese Journal of Geotechnical Engineering,2016,38(8):1497-1506.
2 Haque K E.Microwave energy for mineral treatment processes—A brief review[J].International Journal of Mineral Processing,1999,57(1):1-24.
3 喻清,丁德馨,张炬.微波辐照技术在矿业中的应用现状及发展趋势[J].黄金科学技术,2017,25(1):112-120.
Yu Qing,Ding Dexin,Zhang Ju. Application status and development trend of microwave irradiation technology in mining[J].Gold Science and Technology,2017,25(1):112-120.
4 Lu G M,Feng X T,Li Y H,et al.Experimental investigation on the effects of microwave treatment on basalt heating,mechanical strength,and fragmentation[J].Rock Mechanics and Rock Engineering,2019,52(8):2535-2549.
5 Peinsitt T,Kuchar F,Hartlieb P,et al.Microwave heating of dry and water saturated basalt,granite and sandstone[J].International Journal of Mining and Mineral Engineering,2010,21(1):18-29.
6 Hassani F,Nekoovaght P M,Gharib N.The influence of microwave irradiation on rocks for microwaveassisted underground excavation[J].Journal of Rock Mechanics and Geotechnical Engineering,2016,8(1):1-15.
7 Santos J,Rossi A.Influence of rock chemical composition in microwave heating and decontamination of drill cuttings[J].Materials Science Forum,2017,899(1):469-473.
8 Lu G M,Li Y H,Hassani F,et al.The influence of microwave irradiation on thermal properties of main rock-forming minerals[J].Applied Thermal Engineering,2017,112(1):1523-1532.
9 Olubambi P A.Influence of microwave pretreatment on the bioleaching behaviour of low-grade complex sulphide ores[J].Hydrometallurgy,2009,95(1/2):159-165.
10 周子龙,李夕兵,刘希灵.深部岩石破碎方法[J].采矿与安全工程学报,2005,22(3):63-65.
Zhou Zilong,Li Xibing,Liu Xiling.Rock fragmentation method in deep level[J].Journal of Mining and Safety Engineering,2005,22(3):63-65.
11 赵伏军,李夕兵,冯涛,等.动静载荷耦合作用下岩石破碎理论分析及试验研究[J].岩石力学与工程学报,2005,24(8):1315-1320.
Zhao Fujun,Li Xibing,Feng Tao,et al.Theoretical analysis and experiments of rock fragmentation under coupling dynamic and static loads[J].Chinese Journal of Rock Mechanics and Rock Engineering,2005,24(8):1315-1320.
12 Thostenson E,Chou T W.Microwave processing:Fundamentals and applications[J].Composites Part A: Applied Science and Manufacturing,1999,30(9):1055-1071.
13 Frosch G P,Tillich J E,Haselmeier R,et al.Probing the pore space of geothermal reservoir sandstones by Nuclear Magnetic Resonance[J].Geothermics,2000,29(6):671-687.
14 Liu D Q,Ge H K,Liu J R,et al.Experimental investigation on aqueous phase migration in unconventional gas reservoir rock samples by nuclear magnetic resonance[J].Journal of Natural Gas Science and Engineering,2016,36:837-851.
15 Zhou K Q,Chu Z H,Zhang Y Z,et al.Research of the detection method and thermal cracking of rock[J].Chinese Journal of Rock Mechanics and Engineering,2000,19(4):412-416.
16 Li X B,Gong F Q,Tao M,et al.Failure mechanism and coupled static-dynamic loading theory in deep hard rock mining:A review[J].Journal of Rock Mechanics and Geotechnical Engineering,2017,9(4):767-782.
17 Li X B,Lok T S,Zhao J.Dynamic characteristics of granite subjected to intermediate loading rate[J].Rock Mechanics and Rock Engineering,2005,38(1):21-39.
18 Zhang W Q,Sun Q,Hao S Q,et al.Experimental study on the variation of physical and mechanical properties of rock after high temperature treatment[J].Applied Thermal Engineering,2016,98:1297-1304.
19 Li H,Shi S L,Lu J X,et al.Pore structure and multifractal analysis of coal subjected to microwave heating[J].Powder Technology,2019,346:97-108.
20 朱晶晶,李夕兵,宫凤强,等.单轴循环冲击下岩石的动力学特性及其损伤模型研究[J].岩土工程学报,2013,35(3):531-539.
Zhu Jingjing,Li Xibing,Gong Fengqiang,et al.Dynamic characteristics and damage model for rock under uniaxial cyclic impact compressive loads[J].Chinese Journal of Geotechnical Engineering,2013,35(3):531-539.
21 宫凤强,李夕兵,刘希灵,等.一维动静组合加载下砂岩动力学特性的试验研究[J].岩石力学与工程学报,2010,29(10):2076-2085.
Gong Fengqiang,Li Xibing,Liu Xiling,et al.Experimental study of dynamic characteristics of sandstone under one-dimensional dynamic coupled static and dynamic loads[J].Chinese Journal of Rock Mechanics and Engineering,2010,29(10):2076-2085.
22 刘柏禄,潘建忠,谢世勇.岩石破碎方法的研究现状及展望[J].中国钨业,2011,26(1):15-19.
Liu Bolu,Pan Jianzhong,Xie Shiyong.On the research development of back fragment and its prospect[J].China Tungsten Industry,2011,26(1):15-19.
[1] Siyu MAO, Ping CAO, Jianxiong LI, Chuanjing OU. Fatigue Damage Analysis of Fractured Sandstone Based on Nuclear Magnetic Resonance T2 Spectrum [J]. Gold Science and Technology, 2020, 28(3): 430-441.
[2] ZHUO Yulong,WANG Xiaojun,CAO Shirong,DENG Shuqiang,LI Yongxin,HAN Jianwen . Study on Relationship Between Pore Structure and Strength Weakening of Rare Earth Ore Under Seepage [J]. Gold Science and Technology, 2017, 25(5): 101-106.
Viewed
Full text


Abstract

Cited

  Shared   
  Discussed   
[1] HAO Chunguang,WANG Yuankui,WANG Ping,W ANG Dequan. The Practice of Stable Yield in Transition Period about Opencut M ining to Well M ine[J]. J4, 2008, 16(4): 70 -71 .
[2] CAI Yinfeng,WANG Yongzhi,GUO Zhonglin. Xiao Tie Shan Mine’s Research of the Law of Ground Pressure[J]. J4, 2004, 12(6): 19 -22 .
[3] SHI Tongji. DISCUSSION ON DEVELOPING TECHNIQUE STATUS EXTRATING GOLD FROM CYANIDE[J]. J4, 2001, 9(6): 22 -29 .
[4] WANG Long-Cheng. Characteristics of the Control Factors of Gold M ine in the West Part of Southern Beishan Area,Gansu Province[J]. J4, 2007, 15(2): 15 -19 .
[5] DIAO Jian-Guo, WANG Long-Cheng. Discussion on Characteristics and Genesis Type of Hongshiquan Uranium Deposit[J]. J4, 2009, 17(1): 38 -41 .
[6] SU Ren-Kui, XU Jian-Bei, CHU Yao-Jun, SONG Chang-Bao. Geological Characteristics and Prospecting potential of DongAn Gold Ore Field in Heilongjiang[J]. J4, 2006, 14(1): 10 -13 .
[7] . [J]. J4, 1989, 0(1): 30 -33 .
[8] LU Tiaojian. The Ore Grade Distribution Features and Grade Prediction of Maquan Gold Deposit,Gansu Province[J]. J4, 2011, 19(2): 1 -7 .
[9] LI Shiqiao,JIA Hongfang,XIE Jieqiao,LIU Duolin. Analysis on the Water Filling Factors of Yangshan Gold Mine,Gansu Province[J]. J4, 2012, 20(1): 82 -85 .
[10] TUN Fu-Jiang, LIANG Qing-Ti. Research on Metallogenic Regularity of Boka Gold Deposit in Yunnan Province[J]. J4, 2011, 19(1): 1 -5 .