Exploratory research in alternative raw material sources and reformulation for industrial soda‐lime‐silica glass batches

Abstract

For energy saving and CO2 emissions reduction, in addition to extending the range of suitable raw material sources for glass manufacture, compositional reformulation, and alternative raw materials have been studied in the context of industrial container and float‐type soda‐lime‐silica (SLS) glasses. Lithium, potassium, and boron were applied to modify benchmark glass compositions. Reformulation impacts on key glass properties including the viscosity‐temperature relationship, thermal expansion, liquidus temperature, forming behavior and color. Compared to the benchmark glass, representative of commercial SLS glasses, melting temperatures (taken as temperatures corresponding to log (viscosity/dPa·s) = 2) of reformulated glasses are reduced by 11°C‐55°C. Investigation of four industrial by‐products (seashell waste, eggshell waste, biomass ash, and rice husk ash), and their potential suitability as alternative glass batch raw materials, was also conducted. Seashell waste and biomass ash were successfully introduced into representative green glass formulations.

Effects of composition and phase relations on mechanical properties and crystallization of silicate glasses

“…It also partly dictates the energy requirements for glass manufacture, hence efforts to reformulate or modify existing commercial glass compositions to provide lower viscosities and thereby achieve lower melting energies and lower CO 2 emissions. 19,37,38 Log (η/dPa-s) = 2 generally corresponds to a viscosity at melting temperature for most sodalime-silica type glass compositions, and it is also regarded as the refining viscosity of molten glass. Liquidus viscosity 39 at log (η/dPa-s) = ~4 or alternatively liquidus temperature (denoted as T Liq ) can, to a degree, be interchangeably used to establish the crystallization properties of glass while new glass compositions are studied.…”

“…High‐temperature viscosity governs the refining of molten glass, along with proper glass redox number and refining agents. It also partly dictates the energy requirements for glass manufacture, hence efforts to reformulate or modify existing commercial glass compositions to provide lower viscosities and thereby achieve lower melting energies and lower CO 2 emissions 19,37,38 . Log ( η /dPa‐s) = 2 generally corresponds to a viscosity at melting temperature for most soda‐lime‐silica type glass compositions, and it is also regarded as the refining viscosity of molten glass.…”

Enhanced Reactivity and Primary Liquid-Phase Forming in Mechanochemically Activated Soda–Lime–Silica Glass Batches

“…8−10 Cullet glass, on the other hand, serves as a fluxing agent and leads to an important reduction in CO 2 emissions from both fuel consumption and raw materials requirements. 10,11 However, detecting and removing contaminants in cullet glass is difficult. Moreover, its use in the flat glass industry, with highly stringent quality standards, is mostly limited to in-house cullet, from within its own manufacturing lines.…”

“…As almost 90% of all the glass produced worldwide, flat glass is, chemically, a soda–lime–silica glass consisting of, basically, Na 2 O (added as soda ash (Na 2 CO 3 )), CaO (added as calcite (CaCO 3 ) and dolomite (MgCO 3 ·CaCO 3 )) and SiO 2 (added as silica sand), with minor amounts of some other constituents. Although significant progress has been made in recent years toward reducing its environmental burden, − glass manufacturing is still an energy-intensive, high-temperature, and highly inefficient process. Depending on its chemical composition, the energy cost of melting one ton of glass is, theoretically, between 2.2 million and 2.7 million Btu (where Btu = British Thermal Unit); however, the energy consumption is, in practice, two or threetimes the theoretical minimum, because of the process inherent deficiencies and losses.…”

“…In this context, compositional reformulation, batch consolidation, and increasing use of recycled glass (cullet) are some of the strategies that have been implemented over the years, to obtain significant savings in both energy consumption and raw materials requirements for glass production. Batch consolidation through pelletizing or briquetting has been shown to minimize batch segregation, while reducing volatilization and dusting, and increasing melting rates. − Cullet glass, on the other hand, serves as a fluxing agent and leads to an important reduction in CO 2 emissions from both fuel consumption and raw materials requirements. , However, detecting and removing contaminants in cullet glass is difficult. Moreover, its use in the flat glass industry, with highly stringent quality standards, is mostly limited to in-house cullet, from within its own manufacturing lines.…”