BRIEF COMMUNICATIONS Evaporation of Sulfur-Lean Melts of the System Cu Ni S

Differential high-temperature mass spectrometry was applied to study evaporation in sulfur-lean melts of the systems Cu S and Cu Ni S at 1500 K. Data on partial pressures and activities of melt com- ponents were obtained. Presently, a new autogenous technology for proc- essing of a nickel-containing copper concentrate ob- tained in converter matte separation is being de- veloped and put into practice. This technology has to produce copper with the minimum possible (for this process) impurity content. 1 The behavior of basic im- purities (nickel and sulfur) in this process is governed by the thermodynamic properties of the Cu Ni S sys- tem at Ni content in the range 0.5 50% and up to 21.0% sulfur. Here we report the results obtained in studying evaporation processes in sulfur-lean melts of the sys- tem Cu Ni S at a temperature of 1500 K by differen- tial high-temperature mass spectrometry. The investigation was performed on an MS-1301 mass spectrometer which, including apparatus units for measurements by the Knudsen effusion method and mass-spectrometric analysis of the vapor phase, allows experimental determination of partial vapor pressures of melt components. In this work, the evap- oration occurred from a double effusion cell made of molybdenum and calibrated by the calcium fluoride vapor pressure (1). The set of studies of evaporation from Cu Ni S melts also included investigations of evaporation from sulfur-lean Cu S melts and measurements of partial vapor component pressures over the Cu 2 S melt. The latter was necessary since Cu 2 S was used as pressure standard in studying Cu S and Cu Ni S melts.