To achieve carbon neutrality and establish a circular economy, glass manufacturers must significantly reduce CO₂ emissions and waste. This includes addressing CO₂ emissions that do not originate from energy production, such as those from carbonates like CaCO₃ and Na₂CO₃. CaCO₃, commonly used in industrial processes, is also a major component of shells and eggshells. These waste shells represent an underutilized resource that can contribute to carbon neutrality by reducing CO₂ emissions. In this study, soda-lime-silicate glass was manufactured by substituting waste shells for limestone, a traditional raw material in glass production. The findings confirmed that pearl shells, black pearl shells, white pearl shells, scallops, and oysters could effectively replace limestone in soda-lime-silicate glass manufacturing. This suggests that incorporating discarded shells as raw materials in glass production has the potential to reduce waste and lower CO₂ emissions. Additionally, it was observed that the type of waste shell and applied heat treatment influenced the color, homogeneity, and foaming properties of the resulting glass.

The method of gripping the edge of the cathode sheet of a lithium-ion battery between electrodes and using high-voltage electrical pulsed discharge to separate and recover the cathode active material from the aluminum foil is an effective recycling method to reduce the energy consumption and environmental impact. In this method, the cathode active material layer is a resistance component between the aluminum foil and electrode. By comparing the results of discharging onto a sheet with a cathode active material layer coated on both sides of the aluminum foil and discharging onto a sheet with aluminum foil exposed on one and both sides, we found that the cathode active material layer between the electrode and aluminum foil acts as a resistor to reduce overheating and vaporization of aluminum, leading to appropriate separation. Conversely, the electrical energy loss is minimized when aluminum and the electrode are in direct contact. As a result, it is suggested that further reduction in the energy consumption of a high-voltage electrical pulsed discharge is possible.

Ceramic pots are used as one of the lunchbox containers; however, most of them are discarded after a single use. In this study, a method was investigated to produce tile-shaped hardened materials with sufficient strength for use as interior materials by utilizing the geopolymerization reaction with waste ceramic pots as a raw material. The hardened materials were characterized using various analytical instruments, and their mechanical properties were assessed through three-point bending tests. The bending strength satisfied the requirements for indoor tiles specified in the JIS A5209 standard, reaching a maximum value of 48.3 N/mm².