A Radiometric Technique for Monitoring the Desulfurization Process of Blister Copper

In this paper, a novel optical technique for following the progress of the blister copper desulfurization process is presented. The technique is based on the changes observed in the continuous spectrum of the visible–near-infrared (VIS–NIR) radiation that the blister melt emits while the chemical reactions of the sulfur elimination process are taking place. Specifically, the proposed technique uses an optical probe composed of an optical fiber, a collimating lens, and a quartz tube, which is immersed in the melt. This optical probe provides a field of view of the blowing zone where the desulfurization reaction occurs. The experimental results show that the melt VIS–NIR total irradiance evolves inversely to the SO2 concentration reported by a gas analyzer based on differential optical absorption spectroscopy. Furthermore, the blister copper spectral emissivity as well as the total emissivity observed throughout the process show strong correlation with the sulfur content during desulfurization reaction.

Removal of arsenic from liquid blister copper during remelting in an induction vacuum furnace

Using a reduced pressure during the smelting and refining of alloys removes dissolved gasses, as well as impurities with a high vapor pressure. When smelting is carried out in vacuum induction furnaces, the intensification of the discussed processes is achieved by intensive mixing of the bath, as well as an enhanced mass exchange surface (liquid metal surface) due to the formation of a meniscus. This is due to the electromagnetic field applied to the liquid metal. This study reports the removal of arsenic from blister copper via refining in an induction vacuum furnace in the temperature range of 1423-1523 K, at operating pressures from 8 to 1333 Pa. The overall mass transfer coefficient kAs determined from the experimental data ranged from 9.99?10-7 to 1.65?10-5 ms-1. Arsenic elimination was largely controlled by mass transfer in the gas phase. The kinetic analysis indicated that the arsenic evaporation rate was controlled by the combination of both liquid and gas-phase mass transfer only at a pressure of 8 Pa.

Looking at the changing composition of blister copper obtained through continuous converting

Conventional converting of nickel-bearing copper mattes in horizontal Peirce – Smith converters does not conform with the current environmental regulations. A general global trend includes a transition from conventional batch converting to a continuous converting process producing running slags. The main purpose of the continuous matte converting process is to obtain commercial blister copper that would not require oxidation during further anode refining. To achieve this, rational process parameters should be strictly maintained. The existing method of monitoring the Vanyukov furnace process that is based on the product analysis is a prerequisite but cannot ensure real-time process control. The blister copper obtained through continuous converting differs from the one obtained through the conventional technology in terms of oxygen and nickel concentrations. That’s why its composition should be constantly monitored. The authors looked at how the composition of blister copper obtained through continuous converting of matte tends to change. Samples of blister copper of different compositions were synthesized that are typical of the start-up mode. When the process temperature rises, the required product characteristics can only be obtained if the oxidation potential is higher. This results in a higher concentration of oxygen in blister copper. Mathematical dependencies were derived between the concentrations of nickel and sulphur in the product at various temperatures and the concentration of oxygen. A technique is proposed that enables a real-time monitoring of impurities in blister copper.

Results of dust factor in copper pyrometallurgy

The dust entering the air of the working zone of metallurgical shops was shown to be presented by a disintegration aerosols originating in crushing and transporting ore materials and condensation occurring in the course of smelting, converting and fire-refining copper. The overwhelming majority of the grains have a size of 2,1-5,0 mm, which determines a fixed condition of the presence of given dust in the working area, its long presence in the deeper parts of the respiratory system. At the preparatory stages in the composition of the dust there are presented significant amounts of crystalline silicon dioxide possessing of the fibrogenic impact on the body. In the dust the presence of the crystalline silicon dioxide, arsenic, nickel, cadmium determines its carcinogenic hazard. The elevated dustiness of the air is noted with the reflective and especially mine melting, due to the imperfection of the technological equipment and sanitary technical devices. Autogenous smelting processes have demonstrated their hygienic advantage over outdated methods of producing blister copper (mining and smelting reflectivity.