Impact of Firing Duration on the Density, Porosity, and Macrostructure of Crucible Specimens Made from Evaporation Boat Waste and Sodium SilicateRusiyanto Rusiyanto, Rifky Ismail, Athanasius Priharyoto Bayuseno, Deni Fajar Fitriyana, Wirawan Sumbodo, Ninda Kurniadi and Umar Makarim WibisonoE3S Web Conf., 674 (2025) 06011DOI: https://doi.org/10.1051/e3sconf/202567406011