Periodic Reporting for period 2 - SULTAN (European Training Network for the remediation and reprocessing of sulfidic miningwaste sites)
Reporting period: 2020-09-01 to 2022-08-31
For more than 100 years the EU mining industries have been discarding their extractive-waste residues. Estimates suggest this represents 29% of the EU-28’s current waste output. When poorly managed these residues are a significant environmental hazard. Sulfidic Cu-Zn, Zn-Pb and Cu-Zn-Pb tailings pose the largest challenge, as they are prone to acid mine drainage. However, these tailings also contain valuable metals. Recently, the European Innovation Partnership (EIP) on Raw Materials launched a “call to arms” to transform the “extractive-waste problem” into a “resource-recovery opportunity”. Additionally, the EIP has warned about the acute shortage of talent in this sector. In order to develop a highly skilled workforce, to mitigate environmental risks and to economically recover valuable raw materials, the ETN for the remediation and reprocessing of sulfidic mining waste sites (SULTAN) provides the first-ever training programme dedicated to the reprocessing of tailings. In order to maximise the EU-wide applicability of the developed valorisation routes, the consortium has closely inspected the stocks and flows of tailings in Europe, in terms of mineralogical chemistry, metal content and EU-wide abundance. SULTAN has decided to focus on the tailings generated by the mineral processing of Cu-Zn ores, Zn-Pb ores and mixed Cu-Zn-Pb ores.
SULTAN has pooled the interdisciplinary and intersectoral expertise of leading EIT RawMaterials members, world-leading mining and chemical companies, covering all the links in the tailings-reprocessing value chain. The general process flow is shown in Figure 1. SULTAN develops cutting-edge methodologies to assess the resource potential of Europe’s main tailings families (WP1) and explores eco-friendly mining chemicals to be used in advanced metal-extraction/recovery set-ups (WP2). SULTAN not only recovers the metals but also valorises the clean(ed) tailing residues in circular-economy applications, incl. inorganic polymers, green cements and ceramics (WP3). In WP4 a novel environmental assessment methodology is developed. The 15 SULTAN ESRs also benefit from a unique soft-skills training programme (WP5) and maximise the impact of their research through dissemination and exploitation (WP6). This will kick-start their careers as highly employable professionals in the EU’s tailings reprocessing/remediation sector, as well as for geological surveys, teaching and scientific organisations, and public bodies.
SULTAN has pooled the interdisciplinary and intersectoral expertise of leading EIT RawMaterials members, world-leading mining and chemical companies, covering all the links in the tailings-reprocessing value chain. The general process flow is shown in Figure 1. SULTAN develops cutting-edge methodologies to assess the resource potential of Europe’s main tailings families (WP1) and explores eco-friendly mining chemicals to be used in advanced metal-extraction/recovery set-ups (WP2). SULTAN not only recovers the metals but also valorises the clean(ed) tailing residues in circular-economy applications, incl. inorganic polymers, green cements and ceramics (WP3). In WP4 a novel environmental assessment methodology is developed. The 15 SULTAN ESRs also benefit from a unique soft-skills training programme (WP5) and maximise the impact of their research through dissemination and exploitation (WP6). This will kick-start their careers as highly employable professionals in the EU’s tailings reprocessing/remediation sector, as well as for geological surveys, teaching and scientific organisations, and public bodies.
In WP1, 3 ESRS develop methodologies to assess the resource potential of Europe’s main sulphidic tailings families. More specifically, ESR1 develops and performs a tailored resource potential methodology for the Cu-Zn tailings from the Neves-Corvo Volcanogenic Massive Sulphide (VMS) ore deposit (Portugal); ESR2 performs an advanced geochemical and geometallurgical study with respect to the tailings of an epigenetic, Mississippi Valley-type (MVT) Zn-Pb deposit in Belgium. ESR3 addresses the tailings of a closed Cu-Zn-Pb mine in the Freiberg region in Germany. ESR3 applies the PERC standard requirements to establish the economic potential of these tailings and constructs, amongst others, a 3-D resource potential model.
WP2 explores the synthesis of novel mining chemicals and advanced processes for metal-extraction and metal recovery from tailings. ESR4 develops novel, selective, bio-based mining chemicals for the froth flotation of Cu-Zn, Zn-Pb and Cu-Zn-Pb tailings. These mining chemicals are based on lignocellulosic materials; Concurrently, ESR5 focuses on the development of ion-flotation chemicals that can be used in the metal-recovery step of the tailings reprocessing chain; ESR6 investigates the basics of selective flocculation for sulfidic ores to allow for a radically improved flotation process; ESR7 investigates the use of microwaves (MW) to increase the selectivity, efficiency and kinetics of and solvometallurgical leaching systems for tailings; Concurrently, ESR8 aims at a new leaching approach using salt-containing water sources, such as sea water, in order to save scarce resources; ESR9 develops a bioleaching approach to extract both valuable and hazardous elements (As,Cd) from Cu-Zn, Zn-Pb and Cu-Zn-Pb tailings. The novelty is that ESR9 targets the use of (halo)alkaliphilic sulphur oxidising micro-organisms that live in neutral to alkaline conditions. These are then used to treat tailings in neutral to alkaline conditions; ESR10 develops an innovative process for the recovery of metal ions from acidic sulphate solutions (as generated by the metal extraction step in SULTAN) by ion flotation.
In WP3, three parallel routes are investigated to valorise the mineral fraction of the SULTAN tailings, which represents more than 90 wt% of the initial mining residue material. ESR11 studies pre-treatment methods to increase the alkali solubility of Al, Si, Fe and Mg from the SULTAN tailings in the synthesis of inorganic polymers from purified mineral residues, targeting sound mechanical properties. In parallel, ESR12 investigates the possibility to blend cleaned tailing residues into the production of ceramics, ranging from roof tiles, blocks to pavers. ESR13 is developing new cement chemistries to develop flowable tailing-based cements for underground applications.
WP4 deals with the environmental assessment of the developed value chains. Considering the presence of low concentrations of hazardous elements (e.g. As, Cd) in sulfidic tailings, ESR14 studies the environmental and health impact of these elements in the processing chain from untreated tailing to final downstream product. Finally, ESR15 performs a Life Cycle Assessment (LCA) of the complete system, collaborating with all other ESRs. The new valorisation processes are benchmarked and compared among each other as well as with the environmental impacts of conventional tailings processing.
WP2 explores the synthesis of novel mining chemicals and advanced processes for metal-extraction and metal recovery from tailings. ESR4 develops novel, selective, bio-based mining chemicals for the froth flotation of Cu-Zn, Zn-Pb and Cu-Zn-Pb tailings. These mining chemicals are based on lignocellulosic materials; Concurrently, ESR5 focuses on the development of ion-flotation chemicals that can be used in the metal-recovery step of the tailings reprocessing chain; ESR6 investigates the basics of selective flocculation for sulfidic ores to allow for a radically improved flotation process; ESR7 investigates the use of microwaves (MW) to increase the selectivity, efficiency and kinetics of and solvometallurgical leaching systems for tailings; Concurrently, ESR8 aims at a new leaching approach using salt-containing water sources, such as sea water, in order to save scarce resources; ESR9 develops a bioleaching approach to extract both valuable and hazardous elements (As,Cd) from Cu-Zn, Zn-Pb and Cu-Zn-Pb tailings. The novelty is that ESR9 targets the use of (halo)alkaliphilic sulphur oxidising micro-organisms that live in neutral to alkaline conditions. These are then used to treat tailings in neutral to alkaline conditions; ESR10 develops an innovative process for the recovery of metal ions from acidic sulphate solutions (as generated by the metal extraction step in SULTAN) by ion flotation.
In WP3, three parallel routes are investigated to valorise the mineral fraction of the SULTAN tailings, which represents more than 90 wt% of the initial mining residue material. ESR11 studies pre-treatment methods to increase the alkali solubility of Al, Si, Fe and Mg from the SULTAN tailings in the synthesis of inorganic polymers from purified mineral residues, targeting sound mechanical properties. In parallel, ESR12 investigates the possibility to blend cleaned tailing residues into the production of ceramics, ranging from roof tiles, blocks to pavers. ESR13 is developing new cement chemistries to develop flowable tailing-based cements for underground applications.
WP4 deals with the environmental assessment of the developed value chains. Considering the presence of low concentrations of hazardous elements (e.g. As, Cd) in sulfidic tailings, ESR14 studies the environmental and health impact of these elements in the processing chain from untreated tailing to final downstream product. Finally, ESR15 performs a Life Cycle Assessment (LCA) of the complete system, collaborating with all other ESRs. The new valorisation processes are benchmarked and compared among each other as well as with the environmental impacts of conventional tailings processing.
SULTAN provides the first-ever training programme dedicated to the reprocessing of tailings. SULTAN has pooled the interdisciplinary and intersectoral expertise of leading EIT RawMaterials members, world-leading mining and chemical companies, covering all links in the tailings-reprocessing value chain. By unlocking the potential of sulphidic tailings – currently waste – SULTAN contributes to a more diversified and sustainable supply chain for base, valuable and critical metals, and novel raw materials for the construction industry, while reducing the risk and long term environmental impact posed by sulphidic tailings.
The SULTAN project website (https://etn-sultan.eu/) is the main hub for communication of project results. Among others, the following items are available on the website: ERR/research introduction, research posters, publications, blogposts. The SULTAN introductory video (https://www.youtube.com/watch?v=jp7t6NwOGzA) was promoted on various other channels reaching more than 15000 views so far.
SULTAN is well embedded in/ and actively contributes to the growth of the network on tailings processing. The long-term sustainability of the network is ensured through a strong link to national/E.U. initiatives (e.g. the H2020 IA NEMO project), active participation in conferences and events in the field, the organisation of the SULTAN symposium and engagement in upscaling of SULTAN technologies, e.g. “KAVA activities” (KIC Added Value Activities) within EIT KIC Raw Materials and EIA/RIA projects in the field.
The SULTAN project website (https://etn-sultan.eu/) is the main hub for communication of project results. Among others, the following items are available on the website: ERR/research introduction, research posters, publications, blogposts. The SULTAN introductory video (https://www.youtube.com/watch?v=jp7t6NwOGzA) was promoted on various other channels reaching more than 15000 views so far.
SULTAN is well embedded in/ and actively contributes to the growth of the network on tailings processing. The long-term sustainability of the network is ensured through a strong link to national/E.U. initiatives (e.g. the H2020 IA NEMO project), active participation in conferences and events in the field, the organisation of the SULTAN symposium and engagement in upscaling of SULTAN technologies, e.g. “KAVA activities” (KIC Added Value Activities) within EIT KIC Raw Materials and EIA/RIA projects in the field.