7 research outputs found
How efficient are metalāpolymer and dualāmetalsāpolymer nonālead radiation shields?
Abstract Introduction Lead shields are often used to attenuate ionising radiations. However, to make lighter, recyclable and more efficient shields compared to lead, combinations of new metallic compounds together with polymer, for example, flexible polyvinyl chloride (PVC) have been developed recently. In this study, the capabilities of nonālead radiation shields made of one or two metallic compounds and polymer were evaluated. Methods Monte Carlo (MC)ābased BEAMnrc code was used to build a functional model based on a Philips Xāray machine in the range of radiographic energies. The MC model was then verified by IPEM Report 78 as a standardised global reference. The MC model was then used to evaluate the efficiency of nonāleadābased garments made of metallic compound and polymer (MCP) including BaSO4āPVC, Bi2O3āPVC, SnāPVC and WāPVC, as well as dualāmetallic compounds and polymer (DMCP) including Bi2O3āBaSO4āPVC, Bi2O3āSnāPVC, WāSnāPVC and WāBaSO4āPVC. The absorbed doses were determined at the surface of a water phantom and compared directly with the doses obtained for 0.5āmm pure lead (Pb). Results Bi2O3āBaSO4āPVC and WāBaSO4āPVC were found to be efficient shields for most of the energies. In addition to the above radiation shields, Bi2O3āSnāPVC was also found to be effective for the spectrum of 60ākeV. Bi2O3āBaSO4āPVC as a nonālead dual metalsāPVC shield was shown to be more efficient than pure lead in diagnostic Xāray range. Conclusion Combination of two metalsāPVC, a low atomic number (Z) metal together with a high atomic number metal, and also singleāmetalāPVC shields were shown to be efficient enough to apply as radiation protection shields instead of leadābased garments
Re-Thinking Mining Waste Through an Integrative Approach Led by Circular Economy Aspirations
Mining wastes, particularly in the form of waste rocks and tailings, can have major social and environmental impacts. There is a need for comprehensive long-term strategies for transforming the mining industry to move toward zero environmental footprint. “How can the mining industry create new economic value, minimise its social and environmental impacts and diminish liability from mining waste?„ This would require cross-disciplinary skills, across the social, environmental, technical, legal, regulatory, and economic domains, to produce innovative solutions. The aim of this paper is to review the current knowledge across these domains and integrate them in a new approach for exploiting or “re-thinking„ mining wastes. This approach includes five key areas of social dimensions, geoenvironmental aspects, geometallurgy specifications, economic drivers and legal implications for improved environmental outcomes, and circular economy aspirations, which are aligned with the 10 principles of the International Council on Mining and Metals (ICMM). Applying circular economy thinking to mining waste presents a major opportunity to reduce the liability and increase the value of waste materials arising from mining and processing operations
Selective flotation of enargite from copper sulphides in Tampakan deposit
Recent research has demonstrated promising results showing the possibility of separating arsenic-copper sulphides from other copper minerals by controlling the potential of the flotation pulp. Most of these studies were conducted on single mineral systems, and the selective removal of arsenic-copper minerals in real ore systems is not well understood, particularly, the effects of mineralogical properties such as liberation and mineralogical association. In this study, two distinct ore samples, termed low arsenic sample (LAS) and high arsenic sample (HAS) were selected from the Tampakan copper-gold deposit in the Philippines, providing a range of arsenic levels. The selective separation of enargite from other copper sulphide minerals in a rougher flotation system under controlled pulp potential was investigated for both samples