The subject of the invention is a process for melting and refining vitrifiable materials, such that all or part of the thermal energy necessary for melting the said vitrifiable materials is supplied by the combustion of fossil fuel(s) with at least one oxidizer gas, the said fuel(s)/gas or the gaseous products resulting from the combustion being injected below the level of the mass of vitrifiable materials (7). The refining of the vitrifiable materials after melting takes place at least partly in the form of a “thin layer”. The invention also relates to the device for implementing the process and to its applications.