Influence of Slag Composition on the Distribution Behavior of Cu between Liquid Sulfide and Cu-Containing Multicomponent Slag via Thermodynamic and Kinetic Assessment

At present, copper smelting slag is not effectively recycled and is wasted. Copper smelting slag contains FexO at more than 40 mass%. For the utilization of copper slag as a Fe resource, it is necessary to separate the Cu in the slag. For copper recycling from slag, FeS-based matte can be introduced to use sulfurization to concentrate Cu from the slag into the sulfide and finally recover the copper. In a previous paper, a kinetic model was developed to simulate the coupled reactions between the multicomponent slag and FeS-based matte by using previously reported thermodynamic data. Building on this work, we carried out equilibrium experiments to supplement the thermodynamic data used in the previously developed model. An empirical formula for the Cu2O activity coefficient of Cu2O-FeOX-CaO-MgO-SiO2-Al2O3 system slag was obtained. In addition, the effect of alumina content in the slag on the Cu2O activity coefficient in the slag was investigated. The model was also supplemented to account for MgO solubility. By the developed model and the industrial conditions, we investigated the effect of slag composition on the behavior of Cu between matte and Cu2O-FeOX-CaO-MgO-SiO2-Al2O3 system slag for the copper loss.

Case study of H2S release and transport in a trunk sewer with drops

Field work was performed to investigate the release of hydrogen sulphide (H2S) and its transport in the sewer trunk with drops in the Bonnie Doon area in Edmonton, Alberta, Canada, in order to develop a proper odor control strategy. The liquid sulfide concentration in the upstream trunk was low (less than 1.0 mg/L), and no H2S gas was detected in the head space under this low concentration. However, high H2S gas concentration was detected in the middle reach of the trunk due to the stripping effect of the three drops (2.7 m, 5.2 m and 2.0 m) along the trunk. The released H2S at drops was then transported in the sewer system and emitted at various locations and caused odor concerns. These drops played an important role in H2S release, and the overall H2S mass transfer coefficient at drops was much higher than that in normal gravity sewers. The overall oxygen and H2S mass transfer coefficient (KLa) was estimated to be around 200 h−1 and 300 h−1 at the first two drops, respectively. Field sampling of biofilm indicates that Desulfomicrobium was identified as the sulfate-reducing bacteria (SRB) responsible for sulfide generation in sewer wall biofilm and Thiobacillus was the only predominant member in manhole wall biofilm contributing to sewer manhole corrosion.