| Abstract Scope |
This presentation summarizes our work on the development of high strength, thermal shock-resistant, high optical absorptivity materials for use as solar thermal transfer media, catalytic substrates for reactive permeable barriers, and stimulation media for oil and gas extraction. A large focus has been on the use of raw materials from domestic and industrial waste streams such as recycled mixed glass cullet, fly ash, mine tailings, metallurgical slags and machining swarf, and cuttings from well drilling. Our technical approach has been to tailor fracture mechanisms, strength, and fracture toughness via microstructural control, engineered stress profiles, and controlled devitrification of a wide range of aluminosilicate compositions. Tailoring specific gravity via redox during sintering has enabled a family of aggregates possessing a core-shell macrostructure while retaining requisite strength. These materials rival commercially available sintered bauxite-based spherical materials with regard to strength, hardness, specific gravity and permeability behavior in ISO 13503 testing. Progression from laboratory development to large scale manufacturing using infrastructure common to the glass and refractories industry will be discussed. The ability to manufacture these high performance materials from inexpensive indigenous raw materials, close to their site of application, offers significant potential for operational cost savings while removing a sizable stream of cast-off materials from engineered landfills. |