A Study on a New Concept of Thermal Hard Rock Crushing.
New Horizons in Rock Mech Part 14th:527-554
A new concept of thermal crushing of hard rocks is examined in this study. The theoretical methods developed to analyze thermal stresses and fragmentation induced by partial and complete surface heating of rock blocks are correlated with experimental results. A three-dimensional state of tensile stresses induced in the rock specimen interior during surface heating initiates fragmentation. Thermal crushing of both good spalling (Sioux quartzite) as well as poor spalling (Dresser basalt) rock types was achieved in laboratory tests. The size distribution of thermally crushed fragments was controlled by varying the thermal shock conditions. Crushed fragment size decreased with increasing intensity of surface heating. The specific energy requirement for laboratory thermal crushing of Sioux quartzite test blocks using multiple heat sources was within 12 kwhr/ton and produced a fragment size distribution of about 0.2 Cm to about 6.0 Cm. The study shows that the process of thermal crushing is feasible and can be applied for size reduction of hard rocks.
New Horizons in Rock Mech., Part V; 14th Symp. on Rock Mech. Asce, New York, PP. 527-554