Evaluation of New Applications of Oil Shale Ashes in Building Materials

Abstract

Achieving sustainable zero-waste and carbon neutral solutions that contribute to a circular economy is critically important for the long-term prosperity and continuity of traditional carbon-based energy industries. The Estonian oil shale (OS) sector is an example where such solutions are more than welcome. The combustion of OS generates a continuous flow of ashes destined to landfills. In this study, the technical feasibility of producing monolith building materials incorporating different OS ashes from Estonia was evaluated. Three binder systems were studied: self-cementation of the ashes, ceramic sintering in clay brick production and accelerated carbonation of OS ash (OSA) compacts. Results showed that most of the OSAs studied have low self-cementitious properties and these properties were affected by ash fineness and mineralogical composition. In case of clay bricks, OSA addition resulted in a higher porosity and improved insulation properties. The carbonated OSA compacts showed promising compressive strength. Accelerated carbonation of compacted samples was found to be the most promising way for the future utilization of OSAs as sustainable zero-waste and carbon neutral solution.

Design of High Volume CFBC Fly Ash Based Calcium Sulphoaluminate Type Binder in Mixtures with Ordinary Portland Cement

“…98% of the ash production) landfilled [ 33 ]. The raw oil shale CFBC ash has weak pozzolanic and self-cementitious properties [ 34 , 35 , 36 ], but the ash has been studied for accelerated carbonation and alkali activation to improve the mechanical properties of the ash aggregates [ 37 , 38 , 39 , 40 , 41 , 42 ].…”

Oil Shale Ash as a Substitutional Green Component in Cement Production

“…The oil shale ash (OSA) is the residual product of the direct burning of the oil shale [1]. This ash becomes more accepted as sub-alternative material in several industrial products manufacturing; especially in the ceramics, water treatment plants and construction materials [2][3][4][5][6] The latter use received massive interests in the last decade with the focus on the cement partial replacement in concrete [7][8][9]. Such replacement promotes reducing the need of high cement ratio in concrete with insignificant differences in the mechanical properties [8].…”

“…The percentages of the OSA replacement in cement vary between 10-30 percent [3,7]. These percentages along with mixing amounts will lead to different cement mixture and, thus, different mechanical properties [6]. Another research paper suggested up to 15% OSA replacement to produce typical Portland cement clinker.…”

The composition and properties of ash in the context of the modernisation of oil shale industry

“…By today, possibilities of using OS ash have been quite extensively studied and some have been realised (mainly based on outdated pulverised firing technology). The related areas are: production of cement and building blocks [18][19][20], preparation of curing mixtures and manufacturing of construction aggregates [21,22], road base construction and strengthening/stabilizing of peat ground arrays [23], backfilling of underground mines [24], quick neutralization of acidic soils and production of granulated soil conditioners with modified composition [25,26]. Oil shale is also utilised as a polymer filler, a raw material for precipitated calcium carbonate production [27][28][29], a component of ceramic plates and geopolymers [30], and materials with zeolitic properties, tobermorites [31][32][33], a phosphorus sorbent in municipal sewage treatment [34,35], and an acidic gases sorbent (CO 2 and SO 2 ) [36,37].…”