Summary description of the project
The project aims to revise the production process in the Vitreous Sanitary Ware (VSW) ceramic sector by introducing relevant amounts of glass cullet waste from urban waste disposal in the ceramic blends formulations. The project focuses process innovations designed to a) provide a sustainable management, in terms of recovery of large amounts of glass cullet waste (soda lime glass: SLG), b)improve environmental performances of the ceramic sector by reducing CO2 emissions, c) enhance sustainability by energy saving and natural resources preservation.
In VSW production no extensive use has hitherto been made of SLG, although its introduction would yield remarkable benefits. The replacement of feldspar-like materials (up to some 40-50%), or of flux agents(about 40-50 %), with SLG would provide: (i) savings in natural resources consumption (often imported because of increasing scarceness in European countries, implying also fuel consumption and emissions for transport); (ii) reductions of process energy consumption and CO2 emissions.
Introduction of SLG allows (a) to lower VSW production’s firing temperatures from 1230-1250°C to1120-1150°C, and (b) to shrink soaking times by 20%. The related CO2 emissions reduction will be quantified through the Life Cycle Assessment. All this can be realized by an acceleration of main ceramic reaction kinetics exploiting the SLG high reactivity.
The obstacles that hamper so far feldspars substitution with SLG are: 1. revision of firing timetemperature cycles as a function of the new compositions with SLG; 2. proper management of the rheological behaviour of slips bearing SLG, in order to avoid an excess of thixotropy which might result in a difficulty of casting; 3. deformations control of large ceramic output owed to pyro-plasticity effects;4. revision of the glaze formulation, so as to have it matching the modified time-temperature cycles of firing and the new bulk compositions, and avoiding an increase of production costs.
Taking profit from promising solutions emerged in Partners’ previous studies/lab-scale experimentations, SANITSER is meant to tackle technological hurdles hampering the introduction of SLG in VSW production, through following targets:
- Deep re-definition of the best performing firing time-temperature cycles as a function of the SLG content.
- Optimization of the firing cycles and slips composition to guarantee preservation of technological quality of the final ceramic bodies with respect to present standards for marketability.
- Revision of the glaze compositions in the context of firing time-temperature cycles fixed anew.
- Adjustment of the process dynamics/parameters as a function of the rheological properties of new slips formulated with SLG.
The targets on the VSW production are:
- to proof technical feasibility of achieving a substitution of about 50% of feldspar saving natural resources’ deposits and preserving landscape.
- to extend the achievements of point a) to slips bearing pitcher and granite proving a possible substitution of 100 %.
- to obtain a reduction of at least 16-18% in energy consumption and in the CO2 emissions of at least 16-18% lowering by 80-110°C the ceramic bodies’ firing temperature and shrinking soaking times.
- to reduce production costs rising industrial competitiveness and promoting a shift from a traditional man-labor-oriented to a technology-driven manufacturing, bearing SLG and pitcher, and eventually to the fully novel one substituting 100% of hard-component (feldspar+quartz) with granite and SLG. During project realization, 120 ton of primary raw materials (feldspar, quartz) will be saved and the same amount of SLG waste recycled; 9500 Sm3 of gas will be saved with related CO2 reduction of 1,3 t, excluding the performances obtained by avoided transport of primary resources.
Impact is expected to be very high, as partners represent the whole supply chain for the ceramic industry.