A combined experimental unit for high-temperature viscosity, density and surface-tension measurements in oxide melts (glasses, metallurgical slags and coal ash) is described. The high-temperature viscometer is based on the Brookfield device whereas the density and surface-tension measurements are based on the maximum-bubble-pressure method. A vertical tube furnace is capable of reaching temperatures up to 1550 • C. An inert (argon) atmosphere allows the use of non-standard, molybdenum spindles for viscosity measurements and permits investigation of melts susceptible to oxidation. The ranges for the measured values are 0.1-460 Pa s for viscosity, 10-500 m N m −1 for surface tension, and (0.2-5)×10 3 kg m −3 for density. Since the range of the pressure transducer can be changed for measurements of higher surface tension and density, the experimental unit can also be used for density and surface-tension measurements in liquid metals and mattes. These high-temperature measurements are accurate to within ±8% for viscosity, ±3% for surface tension and ±1% for density.

The properties of liquid slag and matte were studied in the autogeneous extraction of copper which occurs in the Vanyukov's furnace, applied in the Balkhash copper-smelting plant (Balkhash Group of Mining and Metallurgical Enterprises, Kazakhstan). The density and surface tension of the melts were measured using the maximum-bubble pressure method, and the viscosity of the melts was measured by the rotational method. These properties were determined in the temperature interval from 1350 ЊC to 1550 ЊC. The temperature coefficients of the surface tension, density, and viscosity were determined, and the technological significance of results obtained is considered.

Slags and matte in Vanyukov's process, an autogeneous method of processing sulfide concentrates of nonferrous metals used in a specially designed furnace at the Balkhash copper-smelting plant (Kazakstan), have been characterized by scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and X-ray diffraction (XRD). The liquid matte was shown to have contained 3.6 wt pct of slag inclusions and about 4 wt pct of magnetite. The solid matte is a mixture of sulfide phases. The liquid-waste slag was shown to have contained 0.6 wt pct of matte inclusions and about 3 wt pct of magnetite. The silicate field of the solid slag consists of two phases, identified as iron orthosilicate and iron metasilicate. It was shown that most slag formation occurred before the emulsion reached the settling tank of the furnace. Thermodynamic calculation of the exchange reactions for the oxide and sulfide components of the slag showed that zinc and lead dissolved in the slag are present mainly as oxides, but with only a small part (10 to 20 pct) in the form of sulfides. By contrast, copper is present in the slag as dissolved sulfides and also as matte reguli. The results of these thermodynamic calculations are supported by the experimental data.