Effect of Geological, Mineralogical Characteristics on Grindability of Bauxite: A Case Study of Indian Lateritic Bauxite Deposits.

Lateritic bauxite are the products of intense sub-aerial weathering of rocks. It is characterized by a particular enrichment of aluminium-hydroxide minerals such as gibbsite, boehmite and diaspore. Bauxite ore is the result of weathering of various parent rocks such as khondalite, Deccan trap basalt, granite gneiss, charnockite, etc. The two types of lateritic bauxite deposits are located in India viz high level and low level (coastal), situated in the regions namely Eastern ghat, Western ghat, central India, Gujarat, and in union territory Jammu. There are distinct geological variations in the mode of occurrence and ore body configuration. The geological, chemico-mineralogical and petrological characteristics are varying in deposits from region to region. The Eastern ghat and west coast bauxite is dominant in gibbsite minerals however, the central Indian bauxite is mixed gibbsitic boehmite and at places diasporic in nature. For the present study, representative samples of bauxite have been collected from Indian deposits. The samples were characterized for chemical composition, mineralogy and petrography. The bond work index tests have been performed on bauxite samples by standard procedure. The bond work index of ore indicates how much energy is required to grind the ore and it is a very significant property from a plant point of view. The laboratory results show that the eastern ghat bauxite is soft (BWI-10 kwh/mt) as compared to Central Indian bauxite (16 kwh/mt). The studies indicate that the base rock/parent rock, geological formation, mineralogy, etc. play an important role in the hardness of bauxite. In the present paper, details of the Bond work index of various bauxite are specified and factors responsible for the hardness of the ore is being highlighted. [ABSTRACT FROM AUTHOR]