ICSREE 2017

星融

Recovery of cathode material from lithium-ion batteries by acid leaching and solvent extraction

Lithium-ion batteries are currently widely used in various field, resulting in a great deal of spent Lithium-ion batteries. In order to avoid environmental pollution, as well as to promote the field of resources circulation, using hydrometallurgy process for the recovery is a sensible method. Cathode material of spent lithium-ion batteries are refined to obtain high value-added cobalt and lithium products based on the chemical behaviors of metal in different condition. In this study, a hydrometallurgy process is adopted for the recovery of cobalt, nickel, manganese and lithium from sulfuric acid leaching liquor. The leaching efficiency of cobalt is 98.5% under conditions of 2M H₂SO₄+10vol% H₂O₂, at 70℃ and 300rpm using liquid/solid ratio 30:1. After the leaching is completed, metal impurities such as copper, iron, and aluminium are removed by Acorga M5640. The solvent extraction of cobalt, manganese, nickel and lithium from sulfate solution is carried out using Cyanex 272 diluted with kerosene. The factors affecting the extraction process are the effect of equilibrium pH and extractant concentration, O/A ratio, temperature. The metal further recovered using precipitation to seperate, and obtain cobalt, nickel, manganese and lithium with purity >99% in operating condition.

Keywords : lithium-ion battery positive electrode material, solvent extraction, leaching , hydrometallurgy , separation

弼程

Recovery of germanium from optical fiber by ion-exchange resin

Due to the rapid development of optical fiber communication in recent years, germanium tetrachloride and germanium dioxide which used in optical fiber demand rises significantly. It has 3% germanium in the optical fiber that is enough high to recycle them.

In this study, we use ion-exchange to separate selectively germanium (IV) from high concentration silicate ion which is 30 times more than germanium. Germanium in solution was recovered on an anion-exchange resin after complexation with catechol. Experiment investigations were undertaken using quaternary ammonium resins: IRA-900 and IRA-958. The influence of pH, time and amounts of resin and catechol on the sorption capacity were investigated. Owing to the selective complexation of germanium ions with catechol, the operation at low pH enhanced the selectivity. And using hydrochloric acid eluted the germanium ions. The best condition of solution is at pH=6, 5 times as high as the germanium molarity of catechol, flow rate=35ml/h and use 0.1M hydrochloric acid to elute, then we can separate 99% germanium from silicate effectively. Obviously, it indicated that process was very a powerful technique for recovering germanium. Germanium (IV) is the lack of resources in the world, and it is also the scattered precious metal .Therefore, the waste optic fiber cable has recovered economic benefits and necessities.

Keywords : germanium recovery, ion-exchange, recycling technology, Waste optical fiber cable

振堯

Neodymium Resources Recycling from Spent Magnets Slurry

Cooling agent mixed with the scraps during the process of slicing and polishing on the permanent magnets which become neodymium-containing magnets slurry. Over 10 tons of slurry produced in Taiwan annually. The analysis of the slurry contains 24.5% of Nd, 72.5 % of Fe and 1.0% of B, which were valuable to recover. The purpose of this recycling process is to build an optimal hydrometallurgy process to recycle the neodymium from the magnets slurry and makes it into neodymium oxides as the final product. The first process includes roasting and hydrochloric acid leaching. Then, using D2EHPA for solvent extraction and sulfuric acid for stripping. Oxalic acid is used to precipitate neodymium oxalate and then undergo calcination. The product is neodymium oxide powder with the recovery rate over 95% and the purity over -99%.

Keywords: Neodymium; Solvent extraction; Neodymium-containing magnets slurry; D2EHPA