RECMINE – Environmental Footprint Reduction through Eco-Friendly Technologies of Mine Tailing Recycling
Project title: ENVIRONMENTAL FOOTPRINT REDUCTION THROUGH ECO-FRIENDLY TECHNOLOGIES OF MINE TAILING RECYCLING (RecMine)
Duration of the project: May 2022 – April 2024
Project code: COFUND-ERAMIN-3-RecMine, contract no. 307
Funder: European Comision, Horizont 2020
Programme Coordinator: Fundação para a Ciência e a Tecnologia (FCT), Portugal
The aim of this project is the valorisation of high-volume mineral residues from mining and different industrial residues (such as coal combustion by-products (CCP) and demolition waste (DW)) for the development of (i) new geopolymers with low CO2 footprint, and (ii) advanced refractories, suitable for 3-D printing applications.
This will be done through the development of two innovative processing techniques that will be able to make the mine tailings and the industrial wastes suitable for replacing the concrete based on Ordinary Portland Cement (OPC), reducing the requirements of primary raw materials, the waste generation and landfilling. It will be ensured that the developed materials (the geopolymers and the refractories) match the technical and environmental criteria for its use in steel industry or civil engineering applications and develop appropriate business models to secure profitability and sustainability.
Accordingly, the overall objective of the project is to use wastes from five different European countries (Romania, Bulgaria, Portugal, Turkey and Spain) for the obtaining of new green materials, considering the advantages introduced by 3D printing method. Therefore, it is expected to obtain technological progress in the manufacture of geopolymers and refractories which use mine tailings and industrial wastes (CCP and/or DW) as raw materials, due to the presence of a SME as end-user. Moreover, knowing that the synthesis of the materials with similar characteristics (Ordinary Portland cement-based materials) involves consumption of virgin raw materials (kaolin, limestone, sand, gravel, clays) or high temperatures for curing or calcination, the project aims the improvement of currently developed materials by obtaining ambient cured geopolymers with 100% recycled raw materials and self-flowing refractories (high-temperature ceramics) with low or ultra-low cement content that are suitable for 3D-printing.
The overall objective of the project (Figure 1) is to utilize wastes from five different European countries (Romania, Portugal, Bulgaria, Turkey and Spain) in order to obtain new green materials, considering the advantages introduced by the 3D printing method.
The main objectives are:
To formulate new technological concepts: to achieve this objective, the eco-friendly technologies of obtaining (i) the new high-performance geopolymers and (ii) the advanced refractories based on mine tailings and/or industrial waste (CCP/DW) will be designed and improved, also, the characterization procedures will be established and the raw materials (mine tailings, CCP and DW) will be collected from different regions of each country.
To propose and demonstrate the obtaining model (obtaining technology): the raw materials will be analysed from the chemical, physical and morpho-structural points of view to establish its identity, purity and quality to ensure the product is suitable for its intended use. Different types of mineral-based geopolymers or refractories will be obtained using appropriate quantities of mine tailings and/or industrial wastes. Establishing a suitable activation method (alkali activation, mechanical activation, or fusion activation) taking into account the characteristics of raw materials. Obtaining geopolymers and refractories based on mine tailings and industrial waste (CCP and DW). Establishing the methods for characterization of the obtained geopolymers.
To validate the eco-friendly technologies in laboratory conditions: this objective will be achieved through advanced material characterization from microstructural (SEM, AFM, NMR and optical micrography), mineralogical (XRD and FTIR), chemical (EDAX, XRF), mechanical (compressive strength, flexural strength, hardness, toughness, elastic modulus and Vicat tests), thermal behaviour (TGA and DTA) and durability (freeze-thaw cycles and leaching) point of view: (i) characterization of the obtained geopolymers and refractories; (ii) optimization of the obtaining methods according to the characterization results; (iii) assessment analysis of environmentally friendly material and (iv) numerical simulation of thermo-mechanical behaviour and life cycle assessment.
To evaluate the geopolymers and refractories for 3D printing applications: this objective will be achieved by 3D printing of geopolymer and refractory mixtures with adequate characteristics: (i) develop a smart 3D printer that can adjust itself according to the thixotropic properties of the developed geopolymers and refractories; (ii) successfully 3D print the selected geopolymers and refractories at various dimensions required for further evaluations; (iii) experimentally determine and computationally model the mechanical properties of the 3D printed materials considering their anisotropy; (iv) experimentally determine thermal and acoustic properties of the 3D printed materials; (v) design a 3D printable structure (such as a one-story residential unit) and computationally evaluate its performance (structural load carrying capacity, energy demand and occupant thermal comfort).
To realize the transition to market of the obtained materials: To achieve this objective, several actions will be carried out: i) Study the building and refractory materials sectors regarding future trends, market volume and the state of the art of 3D printing on them. ii) determine potential customer model companies and sectors, as well as possible competitors in the fields of 3D printing of geopolymers and refractories. iii) Compare developed technology versus conventional technology in terms of time and economic savings to improve market and social acceptance.
The expected outcomes are to obtain technological progress in the manufacturing of geopolymers and refractories, using mine tailings and industrial wastes (CCP and/or DW) as raw materials. In accordance with subtopic 3.1. “Valorisation of by-products, co-products” and 3.2. “Tailings from mining”, the proposal addresses recycling of waste (mine tailings and CCP/DW) through a low energy consumption method.
Moreover, based on the knowledge that the synthesis of the materials with similar characteristics involves consumption of natural raw materials (kaolin, limestone, sand, gravel, clays – related with OPC-based concrete) or high temperatures for curing or calcination (high energy consumption – related with currently obtained geopolymers) and in accordance with subtopic 2.2. “The use of materials that facilitates reuse”, 2.3. “Use of materials that are recyclable” and 2.4. “Substitution of primary raw materials with secondary raw materials”, the proposal approaches the improvement of currently developed materials by obtaining ambient cured geopolymers with 100% recycled raw materials and self-flowing refractories (high-temperature ceramics) with low or ultra-low cement content with a large amount of mineral residues.
Relevance and expectation: The technologies will serve as a benchmark for research institutions and companies interested in developing a more sustainable environment or those which desire to contribute to the soil decontamination or clearing of dumps area. The obtained materials will become proof-of-concept for further research on the recycling of end-life materials. Local entrepreneurs will improve their understanding of how to collaborate more efficiently with universities to foster their innovation process, products and services.
The project will contribute to the development of competitive technologies to valorise, convert and transform mine tailings and industrial waste (CCP and DW) into raw materials for civil engineering applications. Additionally, the natural raw materials will be preserved, while the CO2 emissions and ecological footprint associated with their exploitation will be significantly reduced.
SCIENTIFIC REPORT – 2022
Contract no. 307/2022; stage no. 1/2022;
Reducing the environmental footprint through ecological technologies for recycling mining waste
In stage 1 of the project entitled “Reducing the environmental footprint through ecological technologies for recycling mining waste” which aims to capitalize on large volumes of mineral residues from mining and various industrial residues (such as coal combustion by-products (CCP) and construction waste (DW)) for the development of (i) new geopolymers with a low CO2 footprint and (ii) advanced refractory materials suitable for 3D printing applications, the following activities were carried out: A1. Collection and processing of raw materials (drying, screening, etc.); A2. Chemical, physical and morpho-structural analysis (XRF, EDAX, SEM, XRD) of raw materials; A3. Establishing the methodology for obtaining geopolymers based on mining waste and/or industrial waste (coal ash/construction waste); and A4. Data dissemination, exploitation and management. Risk analysis plan. Promotion of project results in the media (round table, workshops).
The results obtained, in accordance with the activities carried out, led to the realization of the following deliverables:
Deliverable 1: Collection and processing of raw materials (drying, screening, etc.). In order to obtain this deliverable, raw materials suitable for obtaining geopolymers were collected and processed (drying, sieving, etc.) from the following locations:
– Sludge dump owned by ALUM s.a. Tulcea – raw material collected: red mud.
– Thermal power plant ash dumps from S.C. property. VEOLIA ENERGIE IAțI S.A. – collected raw materials: thermal power plant fly ash and lime ash.
Deliverable 2: Bulletins of analysis and characterization of raw materials. In order to obtain this deliverable, the three types of raw materials collected were analyzed chemically (XRF and EDAX), physically (determination of specific density) and morpho-structurally (SEM and XRD) by means of specific methods and equipment.
Deliverable 3: Methodology for obtaining geopolymers. In order to obtain this deliverable, 9 different geopolymer mixtures were designed, consistent with the L9 orthogonal matrix Taguchi method (36). Thus, the methodology for obtaining geopolymers and the main factors that can influence the performance of the studied materials were established.
Deliverable 4: Dissemination of results. Articles published in international journals. Participation in conferences and presentation of the intermediate results of the project. In order to fulfill this deliverable, the brief description of the RecMine project is published online at https://simtit.ro/recmine/. The preliminary results obtained as a result of the activities carried out were disseminated in specialized journals in the following scientific articles: DOI: 10.3390/ma15124178; DOI: 10.3390/coatings12091348; DOI: 10.3390/cryst12091313. Also, the concept of sustainable development promoted by the RecMine project was presented at several conferences and invention salons where it was awarded as follows:
- The Special Prize awarded by the Highly Innovative Unique Foundation (HIUF) at the European Exhibition of Creativity and Innovation (EUROINVENT), May 26-28, Iasi, Romania.
- Certificate of Excellence awarded at The 7th International Invention Innovation Competition in Canada, iCAN, August 27, 2022, Toronto, Canada.
- Diploma of excellence and the gold medal awarded by the Forum of Romanian Inventors Iași at the International Salon of Scientific Research, Innovation and Invention PRO INVENT 2022, October 26-28, 2022, Cluj-Napoca, Romania.
- The Prize of the Faculty of Materials and Environmental Engineering awarded by the “Gheorghe Asachi” Technical University at the International Exhibition of Scientific Research, Innovation and Invention PRO INVENT 2022, October 26-28, 2022, Cluj-Napoca, Romania.
Also, within the project, a Workshop was held on May 27, 2022, which was announced on the http://www.euroinvent.org/conference/program/ page.
In relation to the project implementation plan, all activities and important milestones have been successfully completed by the project team.