Projeto PRR

Sumário

Job main focus will be on topics related to the life cycle of primary raw materials (availability; prospection, recognition and exploitation; beneficiation and processing; disposal, treatment and recycling of mineral wastes). This “strategic focus” means a fully commitment to the new trends of research and exploitation of raw materials: Sustainable exploitation; Remining; Reuse; Recycling, putting particular emphasis on development of new materials and/or new applications for old materials.Minimization of negative environmental, economic, and social impacts of mining activities can/must be achieved promoting a comprehensive and holistic development of mining, fostering horizontal relationships among multiple stakeholders in the supply chain. This implies a more integral resource extraction to avoid as much as possible to produce huge amounts of wastes; for that, it’s essential to explore pathways to exploite also the low-grade minerals therefore being vital to support a research based on production of low-cost materials. Alkali-activated materials production may constitute a waste management solution and its derived products a replacement for cementitious materials in particular applications.The use of rejects is both an opportunity and a requirement to achieve sustainable and eco-friendly mining exploitation. Thus, it is possible to minimize the overall environmental impact of the exploitation, through its systematic evaluation, and to increase the efficiency and sustainability of the production processes, reducing the consumption of resources and minimizing the volume of fine tailings, taking into account that the handling and processing of mining waste are an integral part of the project.It is intended to transform fine rejects into raw material; The rejects will be essentially alumino-silicate materials, which will allow the development of 3 product lines, with increasing degrees of innovation:Silica, as a raw material for the ceramic and glass industries;Alumino-silicate, feldspathic and clayey white pastes for the white ceramic industry (in particular for flooring and wall coverings);Geopolymers, alumino-silicate materials (with high Si content), with new but growing application in industry (potential cement substitutes) Scientific Profile:For these pretended goals, the demanded scientific profile is a PhD owner (in Geosciences, Chemistry), with at least 5 years of pos-doctoral research experience in the fields of silicate minerals crystallochemical characterization, minerals alkaline activation and geopolymerization as well as strong laboratorial skills in XRD, XRF, SEM/EDS and FTIR analyses of silicate minerals.The contracted researcher must have skills and experience to direct and perform advanced studies at laboratorial and semi-industrial scale of the fine rejects, for each of the potential uses, respectively:processes of beneficiation of the most silicate phases, using disaggregation, comminution, dehydration, flotation using organic acids and granulometric, gravitational or magnetic separation; very recent studies are also testing a process of chemical extraction of silica (fusion with sodium hydroxide);particle size separation processes to obtain the finer, more aluminous phases, which will be subjected to physical (e.g. sonication) and chemical (e.g. chemical activation) beneficiation processes to improve the degree of whiteness and rheological properties;Synthesis of zeolites, from the most aluminosilicate and kaolinite-rich phases.Geopolymerization of the intermediate phases, alumino-silicate (but predominantly siliceous), by chemical means (alkaline activation), with reduced thermal activation, and with the incorporation of national raw materials (kaolin) of low quality (from neighboring farms) of low/zero commercial value. Rationale for Hiring:This job program will allow a relevant advance compared to what currently exists, as it will exploit all the added value that these by-products may have and thus increase the value chain in mineral (for instance, lithium in pegmatites) extraction, allowing valorization of fine rejects (with abundant alumino-silicate phases, such as feldspars, quartz and clay minerals) through their compositional characterization and beneficiation and transformation processes into new geomaterials, as well as their adaptation to market requirements.This way a Researcher is needed to focus on one hand the reduction of used thermal energy (and CO2 emissions) and on the other hand the replacement of most common precursors/raw materials by low-grade ones and mining wastes, producing, at lab-scale, alkali-activated materials, also called geopolymers, aiming an extensive range of applications (construction materials but also for filtration /sorption of PHE); in particular, research must be done aiming to improve mechanical properties and the ability to withstand high temperatures and chemical attack by acids and salts.