Alternative raw material research for decarbonization of UK glass manufacture

Based on the current UK decarbonization policy, a general outlook on potential routes for the glass industry to achieve net-zero is discussed and the differentiation during decarbonization is specified. Biomass ash is considered a potential alternative raw material for low-carbon glass manufacture as it is rich in certain advantageous components, chiefly network modifiers. Simple sieving processes were shown to effectively separate impurities such as S, Cl, and C from some biomass ashes according to particle size distribution. The concentration of undesirable impurities decreased with increasing particle size. Morphologies and X-ray diffraction patterns of larger washed biomass ash particles indicated liquid/amorphous phase formation during biomass combustion. The washing of ashes was also shown to be a potential route to purification. A washed bracken ash relevant to both modern and ancient glass production was characterized for comparison. Ultraviolet-visible near-infrared (UV-Vis-near IR) absorption spectra of representative green container glasses produced using biomass ash confirmed that ∼5 wt.% ash in representative glass batches has little impact on the color and redox state of glasses; the redox status of glass produced using >2 mm biomass ash after washing was less reduced than that of glass produced using high levels (>∼9 wt.%) of >2 mm biomass ash after sieving alone, observed via the redox couple Cr³⁺/Cr⁶⁺ by UV-Vis-near IR absorption spectroscopy.