Separation of demineralized graphite from Egyptian ore by hydrometallurgical treatments

This paper focuses on the separation of demineralized graphite from Bent Um Qureia ore at the Eastern desert of Egypt. Minerals in ore were evaluated Ly XRD and SEM investigations and two routes were used. The first route inc luded fine grinding, hydrocyclone and flotation from which a poor grade and low yield of carbon were obtained. The second included jaw crushing, attri tion scrubbing, triple hydrocyclone separation and two flotation circuits u sing kerosene as a collector followed by acid leaching. Factors affecting t he graphite grade and separation efficiency eta(s) were investigated. A mat hematical model is suggested to explain the results based on the thermodyna mic properties of the minerals involved. Results obtained revealed the pres ence of 14% by weight of carbon in the ore. A further seven undesired miner als, namely antigorite, talc, chlorite, tremolite, feldspar, calcite and qu artz were present in ascending order. The second route was found acceptable for achieving high phi(p) and eta(s) values. Most of these minerals cohere d to graphite by interface forces of a physical order. So hydrometallurgica l acid leaching was applied to remove calcite and silicate-bearing minerals . The activation energy Delta E of this step amounts to 44.42 kJ/mol. Low a sh graphite grade (0.2% ash) with an eta(s) value amounting to 98.5% was su ccessfully separated. The method applied complies with pollution control me asures. The processed water is recyclable and the tailings were found suita ble for use in the refractory industry.