Acid treatment of oil shale ash, its utilization as a substitute of natural aggregates, sand, and cement in concrete

Oil shales are rocks that contain organic matter, at a concentration that allows their utilization as an energy source. As a result of the shale burning process, large quantities of related combustion products are created.

These combustion products contain a high concentration of calcium anhydrite (CaSO₄) and calcium carbonate (CaCO₃), which can be utilized to neutralize acidic wastes (e.g., H₃PO₄).

It was shown that using oil shale without any further treatment caused significantly decreased performances of the concrete mixtures. However, by blending the oil shale with acidic materials, the concrete properties were improved, as the compressive strengths development and the workability of the concrete mixtures.

In the current study, it was shown that the treatment of the oil shale ash with the acidic waste of the Israeli phosphate industry improved the properties of the concrete mixtures significantly, by partial replacement of the natural aggregates and sand by oil shales.

References

[1] R. Hanni, “Energy and valuable material by-product from firing estonian oil shale,” Waste Manag., vol. 16, no. 1–3, pp. 97–99, 1996.

[2] Russell, P. L. Oil Shale’s of the World, Their Origin, Occurrence, and Exploitation. – Pergamon Press, 1990, 753 P.

[3] Kikas, V. Application of oil shale ash in the building materials industry. UN Symposium of oil shale resources. Tallinn, 1968