Abstract: A wireless communication system comprising a plurality of base station devices including a first base station device and a second base station device, wherein the first base station device connected with a terminal determines whether to continue connection with the terminal or not on a basis of a communication quality requirement of the terminal and a resource that can be provided to the terminal, and the first base station device transmits a control signal instructing connection with the second base station device to the terminal in a case where the first base station device determines not to continue the connection with the terminal.

Abstract: Provided is a method for enabling recovery of metal element leaching capacity of a deep eutectic solvent used for leaching a metal element from an ore containing the metal element. A method for recycling a hydrophobic deep eutectic solvent disclosed here includes: preparing a hydrophobic deep eutectic solvent used for leaching a metal element from an ore containing the metal element; and bringing the hydrophobic deep eutectic solvent and hydrochloric acid into contact with each other. In the hydrophobic deep eutectic solvent, a hydrogen bond donor is a carboxy group-containing compound, and a hydrogen bond acceptor is chloride salt. The amount of use of the hydrochloric acid is such that hydrogen chloride is 1 mole or more with respect to 1 mole of the hydrogen bond acceptor.

Abstract: Provided is a method for leaching nickel from a nickel oxide ore that enables a nickel sulfate production method which is easily carried out with a small amount of waste generation. The method for leaching nickel into an organic phase disclosed here includes the step of bringing a nickel ore into contact with an organic phase. The organic phase contains a hydrophobic deep eutectic solvent including a hydrogen bond donor and a hydrogen bond acceptor, and an organic acid. The hydrogen bond donor is an acidic hydrogen bond donor. The organic acid is a strong acid.

Abstract: Provided is a novel method of producing nickel sulfate from nickel oxide. The method of producing nickel sulfate herein disclosed includes a step of feeding nickel oxide particles and an acid aqueous solution into a pressure resistant container, a step of heating the pressure resistant container in a sealed state to a temperature exceeding 100° C. to obtain a mixed liquid in which nickel oxide is dissolved, and a step of forming nickel sulfate, using the mixed liquid.