Applicability of pre-heating techniques for recovery of minerals from rocks

Abstract

In mineral processing industry, liberating of minerals is the most important involvement because it can enhance the purity of the mineral. However, if we can initiate micro-cracks in rock pieces in advance to these operations, it would be more economically viable. Hence, there is a trend i n the world to investigate less energy-consuming methods for propagating micro cracks within rock grains. Previous studies show that preheating techniques such as heating in muffle furnace, microwave preheating can enhance micro-cracks propagation in rocks and samples. Microwaves have several advantages over standard heat application methods namely that they heat only "responsive" phases. Microwaves also heat considerably faster than conventional heating methods as the heating on radiation and conduction heat transfer mechanisms. Therefore, in this scientific investigation, we applied microwave pre-heating technique to liberate Garnet from Garnet Biotite Gneiss for which samples were collected from Boulder Mix Pvt. Ltd quarry in Meepe. To create a weak zone i n between graphite and its gangui rock in graphite bearing rocks which were collected from Bogala Mines in Aruggammana have also tested. Industrial price of garnet vary w i t h the particle size. In general, higher the particle size, higher w i l l be the value. Hence, the recovery of Garnet in this study was considered focused on industry needed particle size which is less than 850 |xm. The analysis revealed that there is a possibility to produce low cost garnet sand which is cheaper than i n the international market with high purity, by means of microwave technology,. Also it is proved that creating a weak zone along the grain boundary of graphite and its gangue rock is possible w i t h microwave pre-heating.