Sulcis coal water jet assisted comminution

Abstract

This study has sought to verify the effectiveness of high-speed water jets on solid minerals grinding. To this end, an innovative gyratory crusher called HERA (High Energy Reduction Apparatus) has been designed and employed. The experiment has been carried out on samples of sub-bituminous coal extracted from the Sulcis coal basin (Sardinia, Italy). The experiment has aimed to examine and evaluate the effects of high-speed water jets on the milled product. These grinding tests have returned carbon suspensions in water, which could be used to power fluidized bed combustors. The parameters used to evaluate the adequacy of the assisted water jet comminution are: jet mill pressure, nozzles size, water flow rate, jets hydraulic power and specific energy consumption. The effects of preliminary water imbibition of coal samples have also been considered. The results have shown that the synergic combination of hydraulic and mechanical energy can have positive effects on grinding.