Design, Optimization and Transfer of a Process for Biodissolution of Precious Metals from Used Electronic Equipment
The recovery of valuable materials from electronic waste is of growing importance for the resource management not only in the industrialized nations. Being a significant step in an innovative automated process for recycling of metals and plastics from used electric and electronic equipment,the results of the work introduced below, prove the applicability of microbial leaching of metals from printed circuit boards (PCBs) at industrial scale.Within the first project step, which started in March 2005, experiments in shaking flasks with a mixed culture of chemolitotrophic bacteria (mainly AcidithiobaciUus ferrooxidans and Leptospirillum ferrooxidans) were carried out to study the solubilization of non-ferrous metals present in the electronic waste. It was found that the best results were achieved by means of a two-stage process in which leaching of these metals was carried out by acidified ferric sulphate solutions generated as a result of the prior bacterial oxidation of ferrous ions to the ferric state. Special reactor systems for bacterial generation of such solutions and for the subsequent leaching of non-ferrous metals from the waste were developed, constructed and tested under laboratory and pilot scale conditions. The optimum technological parameters such as concentration of iron ions, pH-value, temperature and presence of nutrients were established for both reactor systems. Parameters such as particle size,pulp density and flow rate of the suspensions being leached were established for the leaching process carried out under continuous-flow conditions. The complex flow sheet reflects a highly efficient technology on the basis of metal recovery, environmental effect and economical acceptance. The process was successfully implemented into an industrial demonstration unit.
Recycling Biohydrometallurgy Electronic Waste Printed Circuit Boards Technology Transfer
C. Stollberg J. Markowski R. Klein P. Ay S. N. Groudev
Brandenburg University of Technology,Mineral Processing and Upgrading of Renewable Raw Materials, Ge Brandenburg University of Technology, Chair of Mineral Processing, Germany Department of Engineering Oeoecology, University of Mining and Geology, Bulgaria
国际会议
XXIV International Mineral Processing Congress(第24届国际矿物加工大会)
北京
英文
2667-2675
2008-09-24（万方平台首次上网日期，不代表论文的发表时间）