A New Hybrid Decision Support Tool for Evaluating the Sustainability of Mining Projects

The integration of sustainable development challenges and opportunities into the decision making process during the design and/or implementation of multi-disciplinary mining projects is generally not supported by decision support systems (DSS). A new hybrid decision support tool, which features an integrated assessment of sustainable development issues as they apply to mining projects, is hereby proposed. The proposed DSS framework, named “Acropolis DSS”, can be used to assist involved stakeholders in critical decisions, especially when addressing issues such as stakeholder participation, transparency, and trade-offs. The proposed DSS is based on a multi-criteria decision analysis combined with the multi-attribute utility theory

BENEFITS OF THERMAL TREATMENT OF WASTEWATER & SLUDGE IN VARIOUS AREAS OF E/M SPECTRUM

Ενώ η θερμική επεξεργασία των υγρών αποβλήτων με Υπέρυθρη Ακτινοβολία (ΥΑ), Μικροκυματική Ακτινοβολία (ΜΑ) και Ραδιοσυχνότητες – Διηλεκτρική Θέρμανση (ΡΣ – ΔΘ) είναι δυνατή για βιομηχανική χρήση για διάστημα πλέον των 60 ετών, η πραγματική χρήση της είναι περιορισμένη, για την επεξεργασία δε της λυματολάσπης έχουν γίνει μόνο σποραδικές προσπάθειες. Ωστόσο, η επεξεργασία αυτή φαίνεται να προσφέρει μοναδικά οφέλη και αναμένεται να συγκεντρώσει το ενδιαφέρον της επιστημονικής / τεχνικής κοινότητας τα επόμενα έτη. Όταν εφαρμόζεται σωστά, μπορεί να βελτιώσει σημαντικά την κερδοφορία της βιομηχανικής επεξεργασίας λυματολάσπης κατά τρόπο που δεν επιτυγχάνεται με τις συμβατικές μεθόδους.While heat treatment of wastewaters with infrared radiation, microwaves and radio frequencies is available for industrial use for more than 60 years, its actual use is limited, while only sporadic efforts have been made for the management of sludge. However, this treatment option seems to offer unique benefits and will attract the interest of the scientific / technical community in the coming years. When properly applied, it can significantly improve the profitability of industrial sludge treatment in a way that is not achieved by any other means

A Review of the Carbon Footprint of Cu and Zn Production from Primary and Secondary Sources

Copper (Cu) and zinc (Zn) with their unique properties are central for economic growth, quality of life, and the creation of new jobs. The base-metal producing sector is, however, under growing public pressure in respect to energy and water requirements and needs to meet several challenges, including increased demand and lower ore grades, which are generally associated with larger resource use. The development of technologies for metal production from secondary sources is often motivated by increased sustainability, and this paper aims to provide further insights about one specific aspect of sustainability—namely, climate change. The paper presents a review of carbon footprints (CF) for Cu and Zn produced from primary and secondary raw materials by analyzing data taken from scientific literature and the Ecoinvent database. Comparisons are carried out based on the source of data selected as a reference case. The data available in the literature indicate that secondary production of Cu and Zn has the potential to be more beneficial compared to primary production regarding the impact on climate change. However, the technologies used today for the production of both metals from secondary sources are still immature, and more research on this topic is needed. The general variation of data suggests that the standardization of a comparison is needed when assessing the environmental benefits of production in line with the principles of waste valorization, the zero waste approach, and circular econom

The Effect of Si/Al on Mechanical Properties and Fracture Behavior of Stainless Steel Mesh/Cr p

In this study, a series stainless steel mesh/Crp reinforced geopolymer composites with different Si/Al molar ratio (N) were designed and prepared, where N = 1.75, 2 and 2.25, respectively. The effect of Si/Al molar ratio in the geopolymer matrix on mechanical properties and fracture behavior of the geopolymer composites were investigated. The microstructure of geopolymer became more compact when Si/Al increased from 1.75 to 2, which was beneficial to the improvement of geopolymer’s mechanical properties. And continuing to rise to 2.25 for Si/Al, the completely curing of geopolymer composites required more time compared with lower Si/Al, which can be attributed to the different microstructure and chemical composition caused by the different Si/Al. The optimum Si/Al molar ratio was about 2 at which the composites samples present the best mechanical properties with the flexure strength of 115.3 MPa and elastic modulus of 11.0 GPa, respectively. The results of fracture behavior suggested that geopolymer composites with N is 2.25 displayed the behavior characteristics of metal materials, which can be attributed to a poor integrated condition in interface between reinforcements and geopolymer matrix

Properties and microstructure of alkali-activated red clay brick waste

Sintered red clay ceramic is used to produce hollow bricks which are manufactured in enormous quantities in Spain. They also constitute a major fraction of construction and demolition waste. The aim of this research was to investigate the properties and microstructure of alkali-activated cement pastes and mortars produced using red clay brick waste. The work shows that the type and concentration of alkali activator can be optimised to produce mortar samples with compressive strengths up to 50 MPa after curing for 7 days at 65 C. This demonstrates a new potential added value reuse application for this important waste material.The authors are grateful to the Spanish Ministry of Science and Innovation for supporting this study through Project GEOCEDEM BIA 2011-26947, and to FEDER funding. They also thank the Institute for Science and Technology of Concrete - ICITECH, for providing the means to carry out this investigation; and Universitat Jaume I, for supporting this research through the research stay granted.Reig Cerdá, L.; Tashima, MM.; Borrachero Rosado, MV.; Monzó Balbuena, JM.; Cheeseman, C.; Paya Bernabeu, JJ. (2013). Properties and microstructure of alkali-activated red clay brick waste. Construction and Building Materials. 43:98-106. doi:10.1016/j.conbuildmat.2013.01.031S981064

Iron oxide-modified nanoporous geopolymers for arsenic removal from ground water

AbstractComposite materials of hierarchically porous geopolymer and amorphous hydrous ferric oxide were produced and characterized as a new potentially cost-effective arsenic adsorbent. The arsenic removal capabilities of the iron (hydr)oxide (HFO) media were carried out using batch reactor experiments and laboratory scale continuous flow experiments. The Rapid Small-Scale Column Tests (RSSCT) were employed to mimic a scaled up packed bed reactor and the toxicity characteristic leaching procedure (TCLP) test of arsenic adsorbed solid material was carried out to investigate the mechanical robustness of the adsorbent. The best performing media which contained ~20 wt% Fe could remove over 95 µg of arsenic per gram of dry media from arsenic only water matric. The role of the high porosity in arsenic adsorption characteristics was further quantified in conjunction with accessibility of the adsorption sites. The new hierarchically porous geopolymer-based composites were shown to be a good candidate for cost-effective removal of arsenic from contaminated water under realistic conditions owing to their favorable adsorption capacity and very low leachability

Near-zero-waste processing of low-grade, complex primary ores and secondary raw materials in Europe: technology development trends

With an increasing number of low-grade primary ores starting to be cog-effectively mined, we are at the verge of mining a myriad of low-grade primary and secondary mineral materials. At the same time, mining practices and mineral waste recycling are both evolving towards sustainable near-zero-waste processing of low-grade resources within a circular economy that requires a shift in business models, policies and improvements in process technologies. This review discusses the evolution towards low-grade primary ore and secondary raw material mining that will allow for sufficient supply of critical raw materials as well as base metals. Seven low-grade ores, including primary (Greek and Polish laterites) and secondary (fayalitic slags, jarosite and goethite sludges, zincrich waste treatment sludge and chromium-rich neutralisation sludge) raw materials are discussed as typical examples for Europe. In order to treat diverse and complex low-grade ores efficiently, the use of a new metallurgical systems toolbox is proposed, which is populated with existing and innovative unit operations: (i) mineral processing, (ii) metal extraction, (iii) metal recovery and (iv) matrix valorisation. Several promising novel techniques are under development for these four unit-operations. From an economical and environmental point of view, such processes must be fitted into new (circular) business models, whereby impacts and costs are divided over the entire value chain. Currently, low-grade secondary raw material processing is only economic and environmentally beneficial when the mineral residues can be valorised and landfill costs are avoided and/or incentives for waste processing can be taken into account

Value added utilization of by-product electric furnace ferronickel slag as construction materials: A review

This paper reviews the potential use of electric furnace ferronickel slag (FNS) as a fine aggregate and binder in Portland cement and geopolymer concretes. It has been reported that the use of FNS as a fine aggregate can improve the strength and durability properties of concrete. Use of some FNS aggregates containing reactive silica may potentially cause alkali-silica reaction (ASR) in Portland cement concrete. However, the inclusion of supplementary cementitious materials (SCM) such as fly ash and blast furnace slag as partial cement replacement can effectively mitigate the ASR expansion. When finely ground FNS is used with cement, it shows pozzolanic reaction, which is similar to that of other common SCMs such as fly ash. Furthermore, 20% FNS powder blended geopolymer showed greater strength and durability properties as compared to 100% fly ash based geopolymers. The utilization of raw FNS in pavement construction is reported as a useful alternative to natural aggregate. Therefore, the use of by-product FNS in the construction industry will be a valuable step to help conservation of natural resources and add sustainability to infrastructures development. This paper presents a comprehensive review of the available results on the effects of FNS in concrete as aggregate and binder, and provides some recommendations for future research in this field

Alkaline activation of ceramic waste materials

Ceramic materials represent around 45 % of construction and demolition waste, and originate not only from the building process, but also as rejected bricks and tiles from industry. Despite the fact that these wastes are mostly used as road sub-base or construction backfill materials, they can also be employed as supplementary cementitious materials, or even as raw material for alkali-activated binders This research aimed to investigate the properties and microstructure of alkali-activated cement pastes and mortars produced from ceramic waste materials of various origins. Sodium hydroxide and sodium silicate were used to prepare the activating solution. The compressive strength of the developed mortars ranged between 22 and 41 MPa after 7 days of curing at 65 C, depending on the sodium concentration in the solution and the water/binder ratio. These results demonstrate the possibility of using alkaliactivated ceramic materials in building applications.The authors are grateful to the Spanish Ministry of Science and Innovation for supporting this study through Project GEOCEDEM BIA 2011-26947, and also to FEDER funding. They also thank Universitat Jaume I for supporting this research through Lucia Reig's granted research stay.Reig Cerdá, L.; Mitsuuchi Tashima, M.; Soriano, L.; Borrachero Rosado, MV.; Monzó Balbuena, JM.; Paya Bernabeu, JJ. (2013). Alkaline activation of ceramic waste materials. Waste and Biomass Valorization. 4:729-736. https://doi.org/10.1007/s12649-013-9197-zS7297364Puertas, F., García-Díaz, I., Barba, A., Gazulla, M.F., Palacios, M., Gómez, M.P., Martínez-Ramírez, S.: Ceramic wastes as alternative raw materials for Portland cement clinker production. 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