RIS ID
29973
Abstract
The electric discharge assisted mechanochemical milling technique has been applied to the reduction of copper sulphide using either elemental magnesium or elemental iron as the reducing agent. X-ray diffraction was employed for phase identification of starting materials and reaction products. After only 5 min processing using the Electric discharge assisted mechanical milling (EDAMM) method, Cu2S + Mg can be fully reduced to Cu + MgS with small amount of CuO, and Cu2S + Fe can be partially reduced to Cu + Cu5FeS4 (bornite). Secondary electron imaging combined with X-ray mapping was used to investigate the distribution of elements within the processed powder particles. In the case of the Mg reduced sample the product comprised large Cu grains of purity >98%, surrounded by regions of agglomerated, small particles of Cu and MgS. In the case of the Fe partially reduced sample the product comprised a mixture of Cu plus Fe phases, frequently surrounded by regions containing the bornite phase. The morphological evidence of the existence of deformed and some re-melted particles was consistent with arguments that high local temperatures can be achieved during EDAMM processing. However the SEM results also indicated that the primary reduction reaction mechanism involved the formation of agglomerates of small particles that did not exhibit melting. Further experiments under impulse plasma mode, both with and without conventional milling applied, demonstrated that a critical condition for the reduction reactions to occur is not based on temperature alone, but on how long the particles are processed within the in the gap between the milling rod and the base, under what may be described as Dusty Plasma conditions.
Publication Details
Calka, A, Wexler, D, Monaghan, BJ, Mosbah, A & Balaz, P, Rapid reduction of copper sulfide (Cu2S) with elemental Fe and Mg using electrical discharge assisted meachanical milling (EDAMM), Journal of Alloys and Compounds, 486(1-2), 2009, p 492-496.