Lowering Of Grinding Energy And Enhancement Of Agglomerate Strength By Dehydration Of Indonesian Laterite Ore

In order to utilize the iron-rich laterite as raw material for ironmaking process, the effect of dehydration on physical properties of its agglomerate was investigated experimentally. The laterite used in this experiment was produced in Sebuku Island (Indonesia) containing 50.88 mass% of iron. The laterite ore was analyzed by X-ray diffraction for its mineral composition. Differential Thermal Analysis was employed for the thermal analysis and High Temperature microscopic observation was conducted to clarify the behavior of dehydration during the thermal treatment. Agglomeration was carried out in the form of briquette and the strength was measured for laterite ore before and after preheating. Furthermore, Grinding Work Index was measured to evaluate the energy consumption for grinding operation.X-ray diffractometry and Differential Thermal Analysis revealed that the iron mainly formed iron oxide hydrate (goethite), and it decomposed at the range of 530-673 K. High Temperature Microscopic observation explained that the dehydration resulted in crack generation. The crushing strength was measured for the briquettes prepared from the laterite with or without preheating. The improvement of crushing strength was obtained by preheating the laterite ore at 673 K for 1 h. The grinding work index for preheated laterite was obtained about 35 % lower than that of no preheated original ore. Generally, the experimental results showed that preheating treatment promoted in increasing the crushing strength of briquette and decreasing energy consumption for the grinding of laterite ore.