Ion-exchange process with chelating resins was investigated for recovery scandium from sulfuric acid aqueous solutions. An iminodiacetic acid type chelating resin, Diaion CR11, had a higher Sc adsorption selectivity than other elements. Diaion CR11 had high trivalent ions adsorption, and almost divalent ions other than nickel were not adsorbed. The adsorbed metal ions were eluted with sulfuric acid, and scandium was separated from aluminum, nickel and chromium. Only iron (III) showed a behavior similar to scandium and was difficult to separate with Diaion CR11. The elution behavior was related to the stability constants of the complex of iminodiacetic acid and metal ions.

Aggregate is important as a basic material that supports Japan's industrial economy, along with steel, cement, wood, and non-ferrous metals as construction materials for civil engineering and construction. After the Great East Japan Earthquake, the importance of aggregate as a basic material was reaffirmed, and the demand for aggregate is currently in a slight increase or leveling off, and the annual production has been around 380 million tons. In this review, overviewing the transition of aggregate production in Japan from the viewpoint of aggregate resources, the current issues and future prospects are explained. It mentions the shift to mining method in harmony with the environment to enable “sustainable development” on the premise of coexistence with the region, which is an important issue in the mining and production of aggregate. Then, it will be described that trends such as the construction of smart mining system that utilize ICT, IoT, AI, etc. with the aim of responding to labor shortages due to the declining birthrate, aging population, and the advent of a declining population.