Beneficiation of Iron ore sample from Bonai, Orissa

Abstract

A Sample of iron ore from Bonai, Orissa, was received from the Indian Bureau of Mines, at the instance of the Ministry of Steel, Mines and Fuels, Government of India, with a request to upgrade agreement for export of iron ore to Japan. The sample assayed Fe, 59.6%, SiO2, 2.23% Al2O3, 4.45% and loss on ignition at 1000° C, 7.5 percent and contained goethite as the principal of iron mineral. Due to low alumina and silica contents in the sample, washing and gravity methods of beneficiation were not successful. Calcining the sample at 500°C and above, eliminated most of the combined water automatically upgrading the sample to over 64% Fe. Heating the sample gradually to 650°C and soaking it at this temperature for half an hour yielded a calcined product assaying 64.1% Fe. The saving in freight for the calcined, enriched ore should more than offset the cost of crushing and Calcining.