Up-cycling of ‘unrecyclable’ glasses in glass-based foams by weak alkali-activation, gel casting and low-temperature sintering

The EU Training Network for Resource Recovery through Enhanced Landfill Mining—A Review

“…This paper was cited in publications on the preparation of glass-containing foams from geopolymers [122] and vitrified MSWI bottom ash [123] in which the formation of wollastonite and the freezing of the microstructural evolution were mentioned. Other papers cited this publication with respect to the recycling of glass waste into foam glass [124][125][126][127][128][129], porous waste glass for lead removal in wastewater treatment [130], lead stabilization through alkali activation and sintering of Pb-bearing sludge [131], utilization of waste glass for the production of sulphuric acid resistant concrete [132], mechanical and alkali activation of MSWI fly and bottom ashes for the production of low-range alkaline cement [133] and foam glass-ceramics [134], inorganic gel casting for manufacturing of boro-alumino-silicate glass foams [135], porous glass-ceramics derived from MgO-CuO-TiO 2 -P 2 O 5 glasses [136], alkali activation of coal and biomass fly ashes [137], nickel-based catalysts for steam reforming of naphthalene utilizing MSW gasification slag as support [138], production of porous glass ceramics from titanium mine tailings and waste glass [139], porous bioactive glass microspheres [140], Al-SiO 2 composites [141], glass-ceramic foams from alkali-activated vitrified MSWI bottom ash and waste glasses [142]. Another study used vitrified MSWI bottom ash as input material to obtain similar porous glass ceramics [143] and was cited by some of the publications that also cited the first study.…”

Porous Glass Microspheres from Alkali-Activated Fiber Glass Waste

“…The sustainability of this approach (e.g., cullet from crushed container used for new containers) is complicated by the need for expensive sorting operations, aimed at separating glass from other materials, glasses of different chemical compositions, or even glasses with different colors [ 3 ]. Some materials, such as residues from the production of glass fibers (fiber glass waste, FGW), are practically ‘unrecyclable’ [ 4 ]. The utilization of FGW can be accomplished either by decreasing the cost of cleaning and sorting through applying new procedures or by applying an up-cycling approach, consisting of the obtainment of innovative products, which could justify the expense of processing [ 5 ].…”

Low‐alkali borosilicate glass microspheres from waste cullet prepared by flame synthesis

“…This happens with medical glasses, 6 lead/barium crystal glasses, and also glass fibers and their composites. 7 These glasses are also oftentimes landfilled directly from their manufacture, if products are faulty. Their reintroduction in a glass batch would cause too many serious technological problems, that is, stones or streaks.…”

“…The aim of upcycling is to provide a product, different from the original one, but possessing an added economic value. Upcycling options for borosilicate glasses include the conversion of cullet into glass foams 7,[15][16][17][18][19] or geopolymers. [20][21][22][23] However, the practical implementations are limited because of (a) the necessity to transport the waste from several distant producing facilities into a processing facility, (b) mixed material characterization, and (c) the material processed on the industrial scale needs to be produced in large and steady quantities.…”

“…During the glass waste treatment, the unrecyclable cullet is sorted out in energetically and technologically expensive procedures, 5 only for then being landfilled. This happens with medical glasses, 6 lead/barium crystal glasses, and also glass fibers and their composites 7 . These glasses are also oftentimes landfilled directly from their manufacture, if products are faulty.…”