ISSN:
1662-9752
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
The hydrometallurgical processing of metal bearing residues is one of the establishedroutes envisaging metals recovery. In these processes, the leaching operation plays a central role asallows the solubilization of metals for further separation and recovery as pure products. This routecan be applied to spent domestic batteries recycling, which studies on sulphuric acid leaching ofspent alkaline batteries are reported in this paper. Material samples used in the trials were preparedconcerning the real proportion of the most common sizes and shapes of batteries found in the usualstream of this type of wastes. The research involved the evaluation of some factors which affectleaching yields namely temperature, reaction time and stirring speed, through a two-level factorialdesign methodology and analysis of variance. In this study, other factors related with leachantconcentration and stoichiometry were maintained constant. Zinc leaching yields were generally highand even near 100% when the high levels of the variables were used, meaning that zinc oxidespresent in the electrodes are very reactive to acid leachant. The variables had all positive effectsbeing temperature the most significant factor (confidence level 99%) while the other factors wereless significant (98.8% for time and 95% for stirring speed). Concerning manganese, leaching yieldsobtained were more dependent from the factors, being also positive and varying from 11% (for lowlevels of factors combination) to 89% (for high levels of factors combination). Temperature andtime were highly significant (confidence levels above 99.9%) while stirring speed was lesssignificant (97%). Contamination of leach liquors with iron was also evaluated since it is animpurity which requires special attention during the process development. For the higher levels ofthe factors (t = 1 h, T=80ºC and ω=400 rpm) the final solution contained 10 g/L Zn, 15 g/L Mn and3.2 g/L Fe. The removal of the iron from the solution is a necessary step prior to the separation andrecovery of zinc and manganese
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/19/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.587-588.763.pdf
