Recycling of the rare earth oxides from spent NiMH batteries using waste metallurgical slag
A high temperature process for recycling spent nickel-metal hydride batteries has been recently developed at SINTEF/NTNU. The spent battery modules were first frozen with liquid nitrogen for the deactivation and brittle fracture treatment. The broken steel scraps and plastics were then separated by mechanical classification and magnetic separation. The remaining positive and negative electrodes together with the polymer separator were heated to 600-800oC in order to remove the organic components and further separate the Ni-based negative electrode. XRF analyses indicate that the heat-treated materials consist mainly of nickel, rare earth and cobalt oxides. The valuable rare earth oxides were further recovered by the high temperature slagging process. The waste calcium silicate slags were used as the rare earth oxide absorbent. After the high temperature slagging treatment, over 98％ of nickel and cobalt oxides were reduced to the metal phase; meanwhile almost all rare earth oxides remain in the molten slags. Furthermore, EPMA and XRF analyses of the slag samples indicate that the rare earth oxides selectively precipitate in the forms of solid calcium cerite (xSiO2·yCaO·zRE2O3). The matrix of slag phases are therefore RE2O3 deficient, typically being less than 15wt％. This provides a sound basis to further develop the high temperature process of concentrating the RE2O3 oxides from the slag phase.
Recycling spent NiMH battery rare earth oxide nickel-based alloy waste slag
Kai TANG Arjan CIFTJA Casper van der EIJK Shawn WILSON Gabriella TRANELL
SINTEF Materials and Chemistry, N-7465 Trondheim, Norway Norwegian University of Science and Technology, N-7491 Trondheim, Norway
国际会议
Ninth International Conference on Molten Slags,Fluxes and Salts(第九届国际熔渣、溶剂与熔盐学术会议 MOLTEN12)
北京
英文
1-8
2012-05-27（万方平台首次上网日期，不代表论文的发表时间）