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- Faramarzpour, A., et al.
(author)
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Calcite in froth flotation - a review
- 2022
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In: Journal of Materials Research and Technology. - : Elsevier. - 2238-7854. ; 19, s. 1231-1241
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Research review (peer-reviewed)abstract
- Calcite is a semi-soluble mineral that can be considered one of the main problematic gangue phases for several different types of valuable sulfides and oxides. Since froth flotation is the main beneficiation technique for upgrading these valuable minerals, calcite flotation separation has been widely investigated. Semi solubility property of calcite makes its flotation complicated. Through the flotation process, calcium particles release cations into the pulp solution, generate similar surface properties throughout ore minerals, consume reagents, and lockdown flotation beneficiation. Over the years, to tackle this complexity, calcite reverse flotation (calcite depression) has become the main technique for its rejection; therefore, there is a gap in its direct flotation investigations. In addition, the low selectivity of the existing depressants enhanced the importance of detailed calcite surface chemistry analyses and the development of more selective depressants. These studies can use various cations and explore their interactions with calcite surface depression. Ultrasonic and leaching pretreatments have been reported to enhance calcite depression as well, although several rooms are still empty in this area. As a review article, this study generally discussed the existing challenges in detail and provided suggestions for future investigation in calcite flotation.
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| 2. |
- V. Saucedo, Mario A., et al.
(author)
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Event Camera and LiDAR based Human Tracking for Adverse Lighting Conditions in Subterranean Environments
- 2023
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In: 22nd IFAC World Congress. - : Elsevier. ; , s. 9257-9262
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Conference paper (peer-reviewed)abstract
- In this article, we propose a novel LiDAR and event camera fusion modality for subterranean (SubT) environments for fast and precise object and human detection in a wide variety of adverse lighting conditions, such as low or no light, high-contrast zones and in the presence of blinding light sources. In the proposed approach, information from the event camera and LiDAR are fused to localize a human or an object-of-interest in a robot's local frame. The local detection is then transformed into the inertial frame and used to set references for a Nonlinear Model Predictive Controller (NMPC) for reactive tracking of humans or objects in SubT environments. The proposed novel fusion uses intensity filtering and K-means clustering on the LiDAR point cloud and frequency filtering and connectivity clustering on the events induced in an event camera by the returning LiDAR beams. The centroids of the clusters in the event camera and LiDAR streams are then paired to localize reflective markers present on safety vests and signs in SubT environments. The efficacy of the proposed scheme has been experimentally validated in a real SubT environment (a mine) with a Pioneer 3AT mobile robot. The experimental results show real-time performance for human detection and the NMPC-based controller allows for reactive tracking of a human or object of interest, even in complete darkness.
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