Emulsification and Flow Characteristics in Copper Oxygen-Rich Side-Blown Bath Smelting Process

Oxygen-rich side-blown bath smelting (OSBS) is a kind of copper smelting technology with high efficiency, energy-saving, and environment-friendly characteristics. However, emulsification and flow pattern as significant hydrodynamic parameters have been rarely studied for the OSBS process. The formation, size distribution of slag-matte droplets, and flow patterns of the melt in the industry were physically simulated and investigated by the water–oil system in this paper. Moreover, a mathematical model was proposed to estimate the interfacial area between the liquid slag and the emulsion droplets. The results reveal that the typical droplet diameter is in the range of 2 mm to 4 mm. The increase in gas velocity leads to decreasing droplet size and increasing the interfacial area. However, the increase of the injection angle tends to generate large droplets, which is not conducive to strengthen the OSBS process. The correlations of average diameter with Weber number are analyzed in the emulsified region. Besides, the flow patterns in the OSBS process can be divided into the chaotic zone and the quiet zone. In the industrial OSBS process, suitable gas velocity and a small injection angle will refine the copper matte droplets and accelerate the smelting process.

A SYSTEM APPROACH TO CARCINOGENIC RISK ASSESSMENT AND MANAGEMENT FOR METALLURGICAL WORKERS EMPLOYED IN VARIOUS BLISTER COPPER PRODUCTION PROCESSES

The paper presents results of the application of the system approach to carcinogenic risk assessment and management based on the identification carcinogens, prediction carcinogenic effects and rationale for targeted preventive and curative measures. Evidence from metallurgical shops where various blister copper production processes are used regardless of the existing smelting technologies shows the risk of cancer to be Federal Service for Surveillance on Consumer Rights Protection and Human Wellbeingeptable even when the working conditions are classified as permissible (class 2) in terms of chemical factors. The highest carcinogenic risk values are observed for occupations with workplaces characterized by a significant release of dust, arsenic being the main risk contributor. In cases of the blast furnace and reverberatory furnace smelting, carcinogenic risks for workers with a 25-year length of employment exceed the permissible level by 17.6 and 28.8 times, respectively, and in the case of bath smelting, carcinogenic risks exceed the permissible level by 5.1 times. The maximum length of employment for bath smelting shop workers amounts to 5.14 years, being by 1.42 and 0.89 years higher than that for the blast furnace and reverberatory furnace smelting shop workers, respectively. The observed cancer mortality rates exceed significantly the expected mortality rates for the tumor of all sites in cases of combined and respiratory cancers. The highest cancer mortality rates were recorded for batch loaders (60%) and smelter (40%) with the highest predicted carcinogenic risk values. Cancer-specific marker levels higher normal ones were detected in 73% of workers from the increased individual carcinogenic risk group. The proposed system approach to carcinogenic risk assessment and management will make it possible to try out components of the risk-based approach in the supervisory activities at industrial facilities with exposure to carcinogens, to establish the acceptable risk levels depending on the length of employment, identify the priority carcinogens; it will also allow indicating a rationale for additional testing for occupational carcinogenesis predictors as part of routine medical examination procedures and to develop preventive measures against key risk factors.