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A considerable portion of energy consumption and, as a consequence, operational costs in mineral processing, is associated with comminution. High Pressure Grinding Rolls (HPGR) are appealing for their energy efficiency and resulting lower operating costs. This article evaluates this technology as an alternative to the conventional fused alumina comminution route of a specific plant comprising a complex roll crushing circuit. Two fused alumina samples, called BT and TB, were submitted to HPGR (open circuit) and physical characterization (DWT, BBWI, bulk density, specific gravity) tests. In addition, simulations were conducted using JKSimMet® 6.0 software, aiming to predict the performance of a closed circuit equipment and scale-up of an industrialscale unit. Product size distributions of the open circuit HPGR tests and closed circuit HPGR simulations were compared with the product size distribution required by the industrial comminution circuit. The required throughput was also evaluated. Results show that the alternative HPGR route provides a remarkable potential for circuit simplification, while considerably reducing the number of comminution equipments from 13 to 1, which facilitates operational control and possibly reduces operating costs. [ABSTRACT FROM AUTHOR]

Vertical Shaft Impact (VSI) crushers have been used as interesting alternatives to cone crushers, particularly in the production of aggregates for the construction industry, not only due to their good energy efficiency but also to their ability to generate more isometric and tougher particles, which is highly desirable in cement mortars and concrete applications. Several mathematical models for the VSI crusher have been proposed in the last two decades or so. The Whiten crusher model, originally developed for cone crushers, has served as the basis of several approaches to model VSI crushers. In the present work, the Andersen/Awachie/Whiten model has been used as the basis for modeling a VSI crusher operating in an industrial plant in Brazil, processing quarry rock to product manufactured sand. Nineteen industrial experiments, covering a range of feed rates, rotor speeds, feed distributor types and feed size distributions, have been carried out. The approach demonstrated to be capable of providing satisfactory estimates of the VSI performance, being able to predict the product size distribution and the specific energy consumption with confidence over a wide range of operating conditions. Since it uses a model that is already available in commercial plant simulators, it may be used, with additional expressions, in simulating any desired circuit. Model parameters such as K 3 and T 10 were found to be particularly influenced by key operational variables such as feed rate and rotor frequency. The significant effect of feed rate on the performance of the VSI crusher studied has been discussed on the basis of simulations of the material flow pattern inside its feed distributing system, simulated using the discrete element method. According to these simulations, it has been inferred that change in the behavior of VSI from lower to higher feed rates may be related to the transition from material being fed predominantly to the rotor, to the increasing contribution of the cascading effect. [ABSTRACT FROM AUTHOR]

• Innovation is key to improving the environmental performance of the mining industry. • Benefits of adopting circularity (open-loop CDW recycling) in mining are exhibited. • Novel LCA scenarios in aggregates production combining state-of-the-art methods. • Mine-to-product simulation assists in reducing epistemic uncertainty in LCA. • Comprehensive and regionalized LCI considering both mine and product life cycles. Sustainability in mining must be envisioned from a more comprehensive perspective that involves the management of primary and secondary resources and that prioritizes the adoption of innovation beyond a techno-economic mindset. The holistic Life Cycle Assessment (LCA) methodology is useful to diagnose the environmental profile of mining operations seeking a greater contribution to sustainability. This work proposes an enhanced life cycle-based approach for the minerals industry, which is supported by mine-to-product process simulation, scenario analysis, and a comprehensive and context-specific data collection involving the life cycles of the product and the mining project. The convenience of this approach in terms of reducing epistemic uncertainty is demonstrated with a Brazilian case study of a large-scale granitic quarry operation. It is shown that mining can contribute to sustainability by adopting sustainability-driven innovation and circularity principles. The proposed methodology can be applied to other mineral commodities and geographic contexts. [ABSTRACT FROM AUTHOR]

Comminution is an essential step in processing itabirite ores, given the need to liberate silica and other contaminants from the iron minerals for downstream concentration and then pellet feed production. In general, these ores in Brazil are not particularly hard to crush and grind, but both capital (CAPEx) and operating (OPEx) expenditures in this stage of preparation can be critical for the project, in particular due to uncertainties in iron ore prices. Several circuits have been designed and are in operation for this type of ore in Brazil; however, it is not yet clear which technologies are more cost-effective and in which configuration they should be applied. This work critically analyzes four comminution circuits for an undisclosed case study. For these circuits, CAPEx, OPEx, and some environmental sustainability indices, as well as qualitative technical criteria, were used in the comparisons. This work concludes that two of these process routes, especially those based on more energy-efficient technologies (and one of these still rarely explored even at bench-scale), have demonstrated to be very attractive from multiple standpoints. [ABSTRACT FROM AUTHOR]

• Froth flotation plays a key role in the recovery of stibnite from primary and secondary sources. • A critical literature review on stibnite flotation had not been undertaken for over 3 decades. • This exhaustive review covers multiple flotation scales, from laboratory to industrial testwork. • Challenges are identified, highlighting research opportunities to enhance stibnite flotation. Antimony has a long and diverse history of applications, and concerns about its future supply have emerged in recent years. Stibnite-bearing ores continue to be the main source of this critical element, although its sourcing from secondary resources (e.g. mine tailings) is becoming increasingly relevant yet technically challenging. In this sense, froth flotation plays a key role in the recovery of stibnite from both sources. In view of this, a comprehensive review of technical and environmental aspects related to the flotation of stibnite across scales (microflotation, bench-scale and industrial-scale) has been carried out. One of the major topics reviewed is stibnite flotation reagents; while the overall practice has been mostly conservative, relying on the use of xanthate collectors and lead nitrate as an activator, less common (bio)reagents for the flotation of stibnite ores of varying complexity have been shown to be a promising alternative. Other challenges identified from the literature are discussed, highlighting areas of opportunities for further research to enhance stibnite flotation, minimise antimony losses throughout the mine life cycle and thus make antimony more available for future generations. [ABSTRACT FROM AUTHOR]

Sustainability science has received progressively greater attention worldwide, given the growing environmental concerns and socioeconomic inequity, both largely resulting from a prevailing global economic model that has prioritized profits. It is now widely recognized that mankind needs to adopt measures to change the currently unsustainable production and consumption patterns. The minerals industry plays a fundamental role in this context, having received attention through various initiatives over the last decades. Several of these have been, however, questioned in practice. Indeed, a consensus on the implications of sustainability in the minerals industry has not yet been reached. The present work aims to deepen the discussion on how the mineral sector can improve its sustainability. An exhaustive literature review of peer-reviewed academic articles published on the topic in English over the last 25 years, as well as complementary references, has been carried out. From this, it became clear that there is a need to build a better definition of sustainability for the mineral sector, which has been proposed here from a more holistic viewpoint. Finally, and in light of this new perspective, several of the trade-offs and synergies related to sustainability of the minerals industry are discussed in a cross-sectional manner. [ABSTRACT FROM AUTHOR]