Ore processing technologies applied to industrial waste decontamination: a case study

Peer ReviewedObjectius de Desenvolupament Sostenible::12 - Producció i Consum Responsables::12.2 - Per a 2030, assolir la gestió sostenible i l’ús eficient dels recursos naturalsObjectius de Desenvolupament Sostenible::12 - Producció i Consum ResponsablesPostprint (published version

Metric contrast of thermal 3D models of large industrial facilities obtained by means of low-cost infrared sensors in UAV platforms

Monitoring for maintenance or studies of energy efficiency in buildings, large infrastructure, industrial facilities, etc., are common nowadays. These kind of studies are developed with inspections which determine the state of the facilities that are analysed. The difficulty is increased along with the size and complexity of the facility itself, and even more when the attribute to be surveyed is not noticeable or responsive for the human eye. In recent years, a series of techniques that rely on different sensors mounted on UAVs allow detecting problems that are associated with facilities of large dimensions. Almost all of them work in the visible band (RGB), but the generation of thermal 3D models permits detecting any heat anomaly related to the functioning of these facilities. This research proposes a methodology and workflow for the generation and Metric Contrast of Thermal Models (MCTM). This methodology is metrically applied to a mining-industrial facility in which thermal conditions have great influence for a proper functioning. For this metric contrast, several distances have been measured in the field and compared to those obtained from the models. The average difference between the true magnitude and those obtained from the RGB and thermal models are 5 and 31 cm, and their standard deviations are 7 and 29 cm, respectively. The comparison between the RGB and the thermal model provides an average distance between points is 0.19 m, and for 75% of the points the distance is lesser than 0.35 m. Although the RGB model is more accurate, the precision of the thermal model is enough for the objectives se

Application Methodology for the generation of 3D thermal models using UAV Photogrammety and dual sensors for mining/industrial facilities inspection

ABSTRACT: Structural inspection activities are necessary to ensure the correct functioning of infrastructures. UAV techniques have become more popular than traditional techniques. Specifically, UAV Photogrammetry allows time and cost savings. The development of this technology has permitted the use of low-cost thermal sensors in UAVs. The representation of 3D thermal models with this type of equipment is in continuous evolution. The direct processing of thermal images usually leads to errors and inaccurate results. A methodology is proposed for the generation of 3D thermal models using dual sensors, which involves the application of RGB and thermal images in parallel. Hence, the RGB images are used as the basis for the generation of the model geometry, and the thermal images are the source of the surface temperature information that is projected onto the model. Mining/industrial facilities representations that are obtained can be used for inspection activities.The authors wish to express their gratitude to the "Concepción Arenal" Grant Programme of the University of Cantabria and to the Government of Cantabria for the financial support provided for the development of the research activities

Optimization of Photogrammetric Flights with UAVs for the Metric Virtualization of Archaeological Sites. Application to Juliobriga (Cantabria, Spain)

ABSTRACT: Three-dimensional models are required to virtualize heritage sites. In recent years, different techniques that ease their generation have been consolidated, such as photogrammetry with Unmanned Aerial Vehicles (UAVs). Nonmetric cameras allow relatively inexpensive data collections. Traditional aerial photogrammetry has established methodologies, but there are not commonly used recommendations for the selection of parameters when working with UAV platforms. This research applies the Taguchi Design of Experiments Method, with four parameters (height of flight, forward and lateral overlaps, and inclination angle of the sensor) and three levels (L9 matrix and nine flights), to determine the set that offers the best metric goodness and, therefore, the most faithful model. The Roman civitas of Juliobriga (Cantabria, North of Spain) was selected for this experiment. The optimal flight results of the average signal-to-noise ratio analysis were height of 15 m, forward and lateral overlaps of 80%, and inclination of 0° (nadiral). This research also highlights the noticeable contribution of the inclination in the accuracy of the model with respect to the others, which is 16.4 times higher than that of the less relevant one (height of flight). This leads to propose avoiding inclination angle as a variable, and the sole development of nadiral flights to obtain accurate models

Explotación de recursos alternativos para la optimización minera, mediambiental y económica del proceso de producción de clinker

En este trabajo de tesis se realiza el análisis de la viabilidad de la sustitución parcial de las materias primas y combustibles tradicionales necesarios en el proceso de fabricación de clinker (para la posterior obtención de cemento), por otros recursos de similares características y mejor comportamiento medioambiental, que contribuyan a un consumo más sostenible de los recursos mineros y energéticos. Las principales materias primas que se utilizan para el clinker son margas, calizas y arcillas, que se obtienen de explotaciones mineras, en su mayor parte a cielo abierto (canteras de áridos y areneros). Respecto al combustible, el tradicionalmente usado es coque de petróleo, subproducto de otro recurso natural. Los recursos sustitutivos propuestos, denominados ¿alternativos¿, proceden de residuos y estériles de diversos sectores, principalmente del sector minero y del sector industrial. El resultado final demuestra que la valorización material y energética de residuos en los hornos de clinker contribuye a aumentar la sostenibilidad del proceso de producción de cemento, muy intensivo en el consumo de materia prima y energía. Los beneficios medioambientales directos son la explotación más racional de los recursos mineros (disminuyendo el aporte necesario de los mismos), la disminución del impacto ambiental de las explotaciones mineras (pues disminuye el impacto visual de las mismas y otros impactos relevantes como las vibraciones, el ruido y el polvo) y la reducción en la emisión de gases de efecto invernadero. Además, desde el punto de vista del tratamiento de residuos se establece una solución integral para determinados tipos de residuos mineros e industriales, evitando otras formas de gestión más perjudiciales medioambientalmente, como la incineración o el vertido controlado. La metodología empleada comienza con la caracterización de posibles recursos alternativos procedentes de residuos asociados al sector minero, industrial y municipal y/o urbano del área de estudio. En concreto, se han seleccionado para su análisis posterior 18 clases de recursos materiales alternativos (9 de ellos procedentes del sector de la minería y 9 de ellos procedentes del sector industrial), y 9 clases diferentes de combustibles alternativos. También se ha realizado un análisis sobre los efectos que determinados elementos inducen en las características finales del clinker/cemento que permite a la doctoranda proponer una tabla de valores límite de contenido en ciertos elementos, que se limitarían en la corriente de material y combustible que entra al horno de clinker. Para este análisis se han incluido los aportes de los recursos alternativos. Partiendo de las características y dosificaciones de un clinker normal y otro sulforresistente, se han diseñado 32 dosificaciones diferentes, remplazando parte de la materia prima tradicional por recursos alternativos. Paralelamente, se han diseñado 36 escenarios de combustión, con mezclas de combustibles tradicionales y alternativos. Todas las dosificaciones y escenarios se analizan desde el punto de vista de su composición química conjunta, con el objetivo de asegurar que su uso no produzca ningún perjuicio en las diferentes etapas de producción en el horno de clinker, ni tampoco en la calidad del cemento final. Por último, se han efectuado 64 combinaciones diferentes de sustituciones materiales y energéticas que son analizadas desde un punto de vista económico, medioambiental, y de ahorro de recursos. En el análisis económico se ha planteado un análisis de sensibilidades que tiene en cuenta el coste medioambiental de las emisiones de CO2 y la puesta en valor que supone la reducción de dichas emisiones. Esto se ha logrado a través de la valoración de los derechos de emisión, contemplando precios actuales y la evolución posible del precio del CO2 en un futuro próximo. Se proponen las alternativas de sustitución más destacadas y se calculan los ahorros netos anuales. La metodología se ha validado aplicándola a una planta tipo con características comunes a la mayoría de las actuales (horno de vía seca dotado de intercambiador de calor con precalcinador y una producción de 2.000 t/día). Se ha demostrado que las combinaciones óptimas son aquellas que contienen cierto poder calorífico residual, (como por ejemplo, el estéril de la minería de carbón), y aquellas que contienen cal parcial o totalmente descarbonatada. De este modo, se abre un nuevo campo de aplicación para los estériles mineros y se contribuye a alargar la vida útil de las explotaciones mineras de rocas industriales

Ore processing technologies applied to industrial waste decontamination: a case study

The correct management of industrial waste, as well as being an environmental obligation, can also be used as an opportunity to reduce costs in terms of energy and raw material consumption. A large amount of waste sand is generated in foundries with a high content of pollutants adhering to its surface structure. In this study, the material utilized consists of a silicic sand that comes from a casting process, with a thin layer of fixed carbon on the surface of the particles. The objective is to remove this contaminant, in order to have clean sands for use in alternative processes, such as in glass raw material, green concrete, or in the recirculation of these in the same process. The mechanical action that is best for eliminating surface attached contaminants is abrasion. In this regard, two specific devices, commonly used in ore processing operations, were utilized to apply energy in a material in order to reach abrasion by attrition, but with different kinetic approaches: stirring in a slurry media and using a light milling, in both cases reducing the grinding media in order to avoid material fracture. The test performance evaluation is mainly focused on the decontamination efficiency, the sand mass recovery ratio, and the energy consumption. The results show that in all cases, liberation is reachable in different levels at different residence times. We were able to decrease the LOI content from 4% to less than 1%, combined with a near 85% recovery rate of clean sand in the case of stirring. In the case of light milling, the results are even better: the final product reached near 0.5% of LOI content, despite mass flow recovery potentially being less than 80%. Finally, we discuss whether energy consumption is the factor which decides the best alternative. The energy consumed ratio when comparing light milling with stirring is near 9:1, which is a significant amount when taking into account the importance of reducing energy consumption in today’s industry due to its economic and environmental impact

3D Documentation with TLS of Caliphal Gate (Ceuta, Spain)

Three-dimensional surveying with a terrestrial laser scanner (TLS) has implied a revolution in the field of 3D modeling, as this methodology provides detailed point-clouds with simplified processes of capture. In addition to the point-clouds, other outputs can be obtained, such as ortho-images, virtual itineraries, 2D cartography, and meshes, which implies a second avenue of multimedia products, such as 3D Portable Document Format (PDF) files and interactive applications. All these options are interesting for the management and broadcast of cultural heritage. The works that have been developed in this research are aimed at setting a workflow for the TLS surveying works and subsequent data management for the generation of a 3D model of the Caliphal Gate of Ceuta, which is considered as one of the most important medieval findings in Spain in recent years, and its immediate surroundings. This model and the different outputs that have been obtained from it allow for the continuation of the historiographic analysis of the complex, while documenting a partial stage in the development of the works of enhancement. In addition to this, these products are not only useful in terms of conservation studies or enhancement, as they are also suitable for the dissemination of the site. Special attention has been set on the paid suitable software for data management while generating the outputs, and for its application by the final users