International Journal of Environment Science and Technology
Center for Environment and Energy Research and Studies (CEERS)
Vol. 6, No. 1, 2009, pp. 57-68
Bioline Code: st09006
Full paper language: English
Document type: Research Article
Document available free of charge
International Journal of Environment Science and Technology, Vol. 6, No. 1, 2009, pp. 57-68
© Copyright 2009 IRSEN, CEERS, IAU
Analysis of shake flask experiments results conducted on residues from hydrometallurgical processes|
Steel, A.; Hawbol, K. & Khan, F.
Hydrometallurgical facilities processing sulfide based ores produce waste residues in the form of sludges that contain concentrations of metals, as well as metal sulfides. As a part of the waste characterization and risk assessment process, a statistical design of experiment was used to assess the significant factors and interactions in the residue leaching process. Two shake flask experiments, a 24 factorial design and 23 central composite design were employed to evaluate the effect of mixing time, test pH, solid/liquid ratio and residue type on acidity, alkalinity, sulfate and metal concentration and pH of the resulting filtered leachate. The results indicate that the variable tested mixing time and solid/liquid ratio most strongly affect metal concentration in the filtrate from waste residue samples tested over a moderate test pH range. When tests were conducted over a longer test period and at lower test pH values, test pH and residue type were dominant factors contributing to residue filtrate metal concentration.
Process waste, leaching, characterization, batch tests, acid generation, factorial design
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