The demand for lithium-ion batteries has been rapidly increasing in the modern electronics and electric vehicle industries. Tremendous lithium-ion battery consumption leads to an increase in battery scrap, which has to be recycled to relieve the shortage of rare resources. We examined a new process for separation of lithium and cobalt ions, and the regeneration of nitric acid from their mixture solution by use of electrodialysis with water splitting and monovalent cation selective bipolar membranes. In the experiment with an electrodialysis cell divided between an anode and cathode with a water splitting, an anion exchange, a monovalent cation selective, and a water-splitting bipolar membrane, lithium ion selectively permeates to strip compartment through monovalent cation selective bipolar membrane. The nitrate ion also permeates through the anion-exchange membrane and regenerated to nitric acid solution by water splitting bipolar membrane. These results revealed that electrodialysis using water splitting and monovalent cation selective bipolar membrane is applicable to the selective separation of lithium and cobalt ions, and regeneration of nitric acid solution.

“Art Clay Silver (Silver Clay)”, developed as a silver recycled product, is a mixture of fine powdered silver and binder for easily making silver accessories after sintering at 650°C. In this study, in order to find the optimum binder amount to maximize the strength of the sintered product, the filling structure of sintered Silver Clay was analyzed at various binder amounts under three particle size fractions (fine, coarse, and their equal weight mixture) on the basis of the measurements of porosity, shrinkage rate, strength, and pore size distribution together with SEM observation. As a result, we found that the filling structure was controlled by changing the particle size and the binder amount, and that the binder addition of 5–8% to fine particle fraction yielded the minimum porosity and maximum strength.

Chloride is one of the effective medium in which platinum group metals (PGMs) can be brought into a solution, thus chlorocomplexes are particularly important in the process chemistry of PGMs separations. Ru(III) chlorocomplexes are poorly extracted into organic solvents, which is due to the charge of the complex as well as those inert character in a solution, that is, formation of RuCl_6–n(H₂O)_n^(3–n)– (n = 1–6). The problem of solvent extraction of Ru from chloride solutions has not yet been solved and there is no effective industrial extractant for Ru.

PGMs are traditionally separated from one another and the other metals by a complex series of selective precipitation techniques and distillation. These are generally inefficient in terms of the degree of separation achieved. Solvent extraction applied to refining process for PGMs offers several advantages over the traditional precipitation methods and distillation. Adding Sn(II) to a Rh(III) feed is a good procedure which can be used to make Rh react more easily to extraction. However, the effect of addition of Sn(II) on extraction of Ru(III) from chloride solution is not clarified.

In the present study, the extraction of Ru from hydrochloric acid solutions with tri-n-octylamine (TOA) and tri-octyl methyl ammonium chloride (TOMAC) were tested to clarify the effect of addition of Sn(II) on the extraction of Ru and stripping of Ru. The addition of Sn(II) was effective for the extraction of Ru, however, the stripping effeciency of Ru was not sufficient.