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Achieving the New World Sustainability Vision 2030 leads to enacting environmental restrictions, which aim to partially or totally reduce the negative impacts of different forms of waste and develop alternative technologies for eco-friendly and cost-effective utilization. Solid waste is a hazardous waste with many environmental and economic problems resulting from its storage and disposal. However, at the same time, these wastes contain many valuable elements. One of these solid wastes is heavy oil fly ash “HOFA” generated in power stations using heavy oil as fuel. HOFA is produced annually in massive amounts worldwide, the storage of which leads to the contamination of water resources by the contained heavy metals, resulting in many cancerogenic diseases. At the same time, these ashes contain many valuable metals in significant amounts, such as vanadium “V” and nickel “Ni” that can be extracted effectively compared to their low content and difficulty processing in their main ores. Hence, recycling these types of wastes reduces the environmental adverse effects of their storage and the harmful elements in their composition. This paper critically reviews the world resources of vanadium-bearing waste and various approaches described in the literature for recovering V, Ni, as well as other valuable metals from (HOFA) and other wastes, including pyro- and hydro-metallurgical processes or a combination. Hydro-metallurgical processes include alkaline or acidic leaching using different reagents followed by chemical precipitation, solvent extraction, and ion exchange to extract individual elements. The pyro-metallurgical processes involve the non-salt or salt roasting processes followed by acidic or alkaline leaching processes. The operational parameters and their impact on the efficiency of recovery are also discussed. The digestion mixtures of strong mineral acids used to dissolve metal ions in HOFA are also investigated. Bioleaching is a promising eco-friendly technology for recovering V and Ni through appropriate bacteria and fungi. Oxidation leaching is also a promising environmentally friendly approach and more effective. Among all these processes, the salt roasting treatment showed promising results concerning the cost, technological, and environmental effectiveness. The possibility of complex processing of HOFA has also been investigated, proposing innovative technology for completely utilizing this waste without any remaining residue. Effective zeolite for wastewater treatment has been formulated as a good alternative for conserving the available water resources.

In the resources sector, artificial neural networks (ANNs) are becoming more and more well-liked. Using datasets of uranium occurrence as input data, ANN technology offers answers to problems. In this paper, a new artificial neural network (ANN) model and Triangulation Irregular Network (TIN) were used for forecasting of uranium occurrence in Gattar II (GII) area, Northeastern Desert, Egypt. The multilayer perceptron ANN model was trained with the Levenberg–Marquardt algorithm, for calculating the uranium (U) occurrence in GII area based on 185 datasets. TIN method showed a clear distribution for uranium ore grade, total gamma ray (total γ-ray) and thorium (Th) content at the studied area. The proposed ANN model achieves coefficient of determination (R2) of 0.993, root mean square error (RMSE) of 67.197%, mean relative error (MRE) of −2.66%, and mean absolute relative error (MARE) of 12.54%.

Banded ferruginous-siliceous formations (FSF) are confined to the Precambrian basement of the Arabian-Nubian Shield within the central part of the Eastern Desert of Egypt. Gold mineralization is spatially associated with banded ferruginous quartzite, representing one of the most ancient manifestations of gold ore. The Precambrian rocks are combined into deposits complex of the Neoproterozoic Pan-African megacycle of the territory development. Banded iron-silicate rocks occur in sedimentary-volcanogenic rocks that were formed in the subduction trough zones, and are represented by metamorphosed ferruginous quartzites, jaspilites and schists. FSF show tectonic dislocations, shear cracks, and fracture cracks made by gold-quartz-sulphide mineralization. Promising for the identification of gold-bearing mineralization in the rocks of the FSF can be iron-silicate deposits with the occurrence of epigenetic hydrothermal activity as a result of activation of the submarine volcanism of the tholeiitic type.