Energy Requirement for Rock Breakage in Laboratory Experiments and Engineering Operations: A Review

Abstract

Based on the review of a wide range of literature, this paper finds that: (1) the average specific surface energy of various single crystals is only 0.8 J/m2. (2) The average specific fracture energy of the rocks with a pre-crack under static cleavage tests is 4.6 J/m2. (3) The average specific fracture energy of the rocks with a pre-cut notch but with no pre-crack under static tensile fracture (mode I) tests is 4.6 J/m2. (4) The average specific fracture energies of regular rock specimens with neither pre-made crack nor pre-cut notch are 26.6, 13.9 and 25.7 J/m2 under uniaxial compression, tension and shear tests, respectively. (5) The average specific fracture energy of irregular single quartz particles under uniaxial compression is 13.8 J/m2. (6) The average specific fracture energy of particle beds under drop weight tests is 74.0 J/m2. (7) The average specific fracture energy of multi-particles in milling tests is 72.5 J/m2. (8) The average specific energy of rocks in percussive drilling is 399 J/m3, that in full-scale cutting is 131 J/m3, and that in rotary drilling is 157 J/m3. (9) The average energy efficiency of milling is only 1.10%. (10) The accurate measurements of specific fracture energy in blasting are too few to draw reliable conclusions. In the last part of the paper, the effects of inter-granular displacement, loading rate, confining pressure, surface area measurement, premade crack, attrition and thermal energy on the specific fracture energy of rock are discussed.

Reduction of Fragment Size from Mining to Mineral Processing: A Review

“…As mentioned in Sect. 1 and the review by Zhang and Ouchterlony (2022), the energy efficiency, i.e., the ratio of the energy used in fracturing rock to the energy input, was only 10%, 6%, 4%, and 1% in rock drilling, blasting, crushing, and grinding, respectively. In short, the disparities between energy efficiencies of drilling, blasting, crushing, and grinding are large.…”

“…A rock with greater specific fracture energy requires more energy to break (Zhang and Ouchterlony 2022). Fragmentation is also affected by water and temperature in the rock.…”

“…A recent review (Zhang and Ouchterlony 2022) confirms that only a very small fraction of energy input is used to create new rock surface area in the mills and single particle impact crushing, resulting in an extremely low-energy efficiency of about 1% in such conventional milling. For example, measurement results have demonstrated that about 75-90% of the energy input is finally degraded into thermal energy; see Sect.…”

“…Unfortunately, the energy efficiency is extremely low in operations, such as rock blasting, crushing, and grinding. For instance, the energy efficiency is about 10% in percussive rock drilling (Carrol 1985), 3-5% in rock crushing (Prasher 1987), approximately 1% in milling (Chi et al 1996;Alvarado et al 1998;Fuerstenau and Abouzeid 2002;Zhang and Ouchterlony 2022), and maximum 6% in rock blasting (Ouchterlony et al 2003;Sanchidrián et al 2007). These extremely lowenergy efficiencies result in a considerable amount of energy wastage and make the mining industry worse than most other industrial sectors regarding energy utilization.…”

An ultrafast time-resolution method based on picosecond pulsed laser for determining rock fracture toughness at multipoint during the crack propagation

“…Studying the fracture process of heterogeneous rock is of great help to establish rock fracture model, engineering stability, hydraulic fracturing, and other engineering applications. For example, effective rock fracture may improve the ore recovery ratio through effective separation of minerals along their grain boundaries in mineral processing 32 – 35 . Jialiang Liu et al studied the crack evolution rules of hydraulic fracturing rock with different hardness 36 .…”