Pour faire face aux enjeux des transitions énergétique et numérique, la demande en ressources minérales va continuer à augmenter de manière importante. Pour autant, la France et l’Europe dépendent beaucoup des importations provenant de pays tiers potentiellement impactées par la montée des tensions internationales. Cette dépendance porte clairement des enjeux de souveraineté industrielle, de coûts énergétiques et économiques, d’impact environnemental exporté, et d’enjeux sociétaux et éthiques liés au transfert d’impact de nos modes de vie. Fort de ce constat, cet article vise à donner une vision synthétique des ressources primaires et secondaires potentiellement disponibles en France et des orientations qu’il nous semble souhaitable de suivre pour redévelopper un tissu industriel dans les territoires, accompagner la transition énergétique et reconquérir notre souveraineté économique tout en servant les objectifs de développement durable des Nations unies.

In line with the perspective of the Raw Material Initiative launched in 2008 by the European Commission to ensure access to and supply of critical raw materials in Europe, the H2020-funded IMPaCT project (Grant no. 730411) aims to develop a Switch-On Switch-Off (SO-SO) concept as an emergence of a new modern small-scale mining paradigm. Its ultimate goal is to increase the viability of many critical metals hosted in small primary deposits, particularly in Europe, by developing a modularized mobile plant (MMP) concept that can economically operate different type of ores in different types of geological and geographical contexts. In addition, the project addresses the prospect of applying the SO-SO concept and the small-scale mining paradigm with regard to the reprocessing of mineral wastes in Europe. A dataset of legacy deposits of interest for the SO-SO concept was drawn from the ProMine Anthropogenic Concentration (AC) database (built during the European FP7 ProMine project) used as the data source and by applying a sequential-rating as a methodology to rank records and to highlight potential targets. Apart from national mining wastes registries, the ProMine AC database remains so far the most exhaustive and reliable attempt at a consolidated pan-European database regarding mining wastes. Despite data shortcoming in the ProMine AC database, this study proposes potential targets of mineral wastes for the SO-SO concept in Europe and provides with preliminary information on location, type of waste, commodities content, tonnage and their potential. To put into perspective the application of the SO-SO concept and the small-scale mining paradigm in regards with mineral wastes reprocessing, this study also proposes generic flowsheets to address specific potential targets identified among the records from the ProMine AC database and based on the preliminary information available. However, the relevancy and completeness of these information still require a case-by-case assessment. As a result, this methodology falls into a scoping approach that could be applied ahead of (pre)feasibility studies. Combining the re-exploitation of a primary ore deposit along with the reprocessing of its wastes inherited from previous mining and ore processing activities is of great interest in seeking social acceptance. Eventually, in such perspective, a cross survey of the potential of both primary deposits, using the ProMine Mineral Deposits (MD) database, and secondary deposits, using the ProMine AC database, therefore appears as a relevant scoping strategy ahead of implementing small-scale mining.

Whereas there are growing needs for mineral resources (metals for the energy and digital transitionsand construction materials), the mining industry must produce them from poorer, moreheterogeneous and more complex deposits. Therefore, volumes of mine waste produced (includingtailings) are also increasing and add up to waste from mining legacy. For example in Europe (x27): 732Mtons of extractive waste are generated per year and more than 1.2 Btons of legacy waste are storedall over the European territory. The localisation (and potential hazards) are well known and coveredby the inventories carried out in EU countries under the Mining Waste Directive.At the same time, Europe is implementing the circular economy approach and put a lot of emphasison the resource efficiency concept. In this context, reprocessing operation to recover both metals andmineral fraction is studied with the objective of combing waste management (reducing final wastestorage and long-term impact) and material production from secondary resources.Numerous industrial experiences of reprocessing of mine waste and tailings exist all over the world torecover metals such as copper, gold or critical raw materials - CRM They concern mainly active minewhere both primary and secondary resources are considered in profitable operations; for example inChile, South Africa, Australia. Mineral fraction recovery is often not considered which still leaves theindustry with a high volume of residual minerals to store and manage.In addition, legacy mining waste are potentially available for reprocessing. In this case, numerousmining liabilities issues need to be managed. Some of the European legacy mining waste have residualvaluable metals that could be recovered but some of them have very low metal contents. In Europe,classical rehabilitation operations – usually at the charge of member states and local authorities – isthe priority and concern the reduction of instabilities and impacts to the environment including heapremodelling, covering and water management with long-term treatment. Completing this riskmanagement approach by a circular economy one is a very active R&D subject in EU27.This presentation will give an overview of EU research projects which tackled the legacy mining wastechallenge from inventory to process development. Several process flowsheets to recover metals weredesigned and tested on several case studies with CRM – REE, Co, W, Sb, etc. Initiatives to reuse mineralfraction are also underway and should be ready for commercialisation in the coming years.Resources efficiency concept and the circular economy implementation starts on mining sites. In orderto facilitate the implementation of this approach, the technical solutions will need to be included ininnovative global initiatives covering also legal (liability management), environmental (Life CycleAnalysis approaches) and social (acceptance) questions.

L’augmentation régulière des concentrations de gaz à effet de serre dans l’atmosphère sous l’effet des activités anthropiques conduit aujourd’hui à des modifications majeures du climat terrestre comme vient de le rappeler le rapport du GIEC. La France s’est engagée dans une stratégie ambitieuse de réduction de ses émissions afin d’atteindre la neutralité carbone en 2050. Cette stratégie repose notamment sur une modification profonde de nos consommations d’énergie en accélérant l’électrification des usages, en améliorant l’efficacité énergétique et en maintenant un mix électrique décarboné. Ces changements requièrent le déploiement de nouvelles technologies bas carbone reposant sur le nucléaire et les énergies renouvelables et sur le numérique (IA, réseau intelligent, etc.), mobilisant des quantités importantes de matières premières, métaux de base et de métaux rares.

Retreatment of metallic tailings: a review and a technico-economic case study In the context of a circular economy, contents of metals and matter in mining residues are pinpoint to recover value from secondary resources and, at the same time manage environmental issues. Numerous case studies of the reprocessing of stockpiles and mining wastes from metal mines all over the world demonstrate the possibility to extract metals of interest, to rehabilitate sites and still keeping the operation economically profitable. There are currently large tailings reprocessing operations outside Europe, including gold and copper mining (Australia, South Africa, Chile). In Uganda cobalt was produced for more than 10 years from an old pyritic tailings which generates acid mine drainage. Some industrial operations are very large-scale with significant tonnages of residues, ranging from several million tons to several hundred million tons, or even billions of tons to treat. Added value is high, especially for gold, since investments are lower than for traditional mine operations. Environmental problems often associated with the waste storage on more or less old exploitations are taken into consideration to reduce global impacts. In Europe, in relation to the mining past, many countries have historic tailings deposits (that can be seen as a stock of secondary material); residues are also produced annually (flows) in some EU-28 countries. Reprocessing experiences are much more limited than in the world and are related to smaller sites, fairly scattered stocks and lower economic value. However, projects are emerging, sometimes in connection with European research funding. Following a pilot operation of retreatment of Pb/Ag tailings (4t) the results of a technico-economic study is also proposed to discuss the issue of retreatment compare to standard rehabilitation.

The European Cluster Conference 2019 provided information and discussions on future priorities for cluster policies, with a focus on connecting ecosystems. EREK, the European Resource Efficiency Knowledge Centre, organised and moderated one of the breakout sessions, “Circular Europe”. The session started by two presentations. The first by Luca Donelli, President of the Lombardy Energy Cleantech Cluster, touched upon the complexity of the world that we live in: a world where change is driven partially driven by buzzwords and hashtags. But whether you talk about Circular Economy or Resource Efficiency or Industry 4.0, the underlying message remains the same. As our value chains are very much interconnected, a change in one country can also positively affect other countries. It is important to keep in mind that companies can’t change the way they produce in one day, but by taking one step at the time a lot can be achieved. Especially if Circular Economy is not view as a specific group of content but applied wider, for example by taking the perspective of environmental cost of production.

Chemie Ingenieur TechnikVolume 90, Issue 9 p. 1277-1277 PosterFree Access Outotec RSA und Biohydrometallurgy: from laboratory scale to industrial application, the Kasese case study P. D'Hugues, P. D'HuguesSearch for more papers by this author P. D'Hugues, P. D'HuguesSearch for more papers by this author First published: 24 August 2018 https://doi.org/10.1002/cite.201855319AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume90, Issue9Special Issue: ProcessNet-Jahrestagung und 33. DECHEMA-Jahrestagung der Biotechnologen 2018September 2018Pages 1277-1277 RelatedInformation

In bioleaching processes using autotrophic bacteria, carbon dioxide (CO2) is the carbon source for the growth of the microorganisms and its availability is dependent on gas mass transfer. The objective of this study was to investigate the demand in CO2 in complex sulfidic copper (Cu) concentrate bioleaching operations and to optimise CO2 supply. Batch tests in 2 t-stirred reactors at 10%(w/v) solid concentration were performed to study the need for CO2-enrichment and to determine the adequate CO2 partial pressure in the gas inlet. The results show that ferrous iron (Fe(II)) oxidation, and thus microbial activity, is delayed when air is injected without CO2-enrichment; the carbonates present in the solid are not sufficient to provide the CO2 required for the activity of Fe oxidising bacteria. CO2-enrichment improves leaching kinetics since the copper dissolution rate increases from 84 mg L-1 h(-1) with air solely to 120 mg L-1 h(-1) when CO2 is added to air. A CO2 enrichment influences both the composition of the bacterial community and the abundance of the bioleaching species. This study proposes also a methodology to determine gas/liquid transfer components and to assess CO2 limitations in the system. It shows that the microorganisms are not only sensitive to the transfer rate of CO2 from the gas to the liquid phase, but also to the availability of CO2 in solution.

Compared to conventional extractive techniques, bacterial assisted leaching, also called “biomining” is an eco-friendly technology that provides improved metal/solid separations. These separations are enhanced by the synergistic activities of astonishingly diverse groups of microorganisms, which lead to an extraction process with low energy consumption, low capital investment and low impact on the environment. Recently, biomining has received great attention in a variety of niche areas, especially in the mineral industries and solid industrial waste materials (e.g. galvanic sludge, sewage sludge, fly ash, electronic waste, spent petrochemical catalysts, medical waste, spent batteries, waste slag) where the metals values are low, or where the presence of certain elements would lead to smelter damage, or where environmental considerations favor biological treatments options. It allows the recovery of metal from low-grade sulfide ores and concentrates that cannot be processed economically by conventional techniques, as well as the production of concentrated metal salt solutions, which could be recycled. Bacterial assisted leaching processes are based on the ability of certain microorganisms to solubilize/or expose the metals contained in the ores and concentrates by direct oxidation, or through indirect chemical oxidation instigated by the corrosive metabolic by-products generated by an electrochemical option, or a combination of both of these. The valuable metals in solution can be recovered using conventional hydrometallurgical techniques. If the material of interest constitutes part of or is in the pre-treated residue then it can be further processed for metal recovery.

The use of oxygen enriched air is a common practice in high-temperature bioleaching tests (>70 degrees C) to overcome oxygen solubility limitation and reduced the energy costs of the process. Air is usually preferred in medium and low-temperature operations mainly for technical and economic constraints. Nevertheless, under high-sulfide loading conditions - high-grade metal sulfide concentrates and high solids concentration - the microbial and chemical demand for oxygen is significantly increased during the bioleaching process. If not satisfied, this high oxygen demand might limit the oxidation efficiency. Therefore it requires the injection of large amounts of air. Sparging with oxygen enriched gas instead of air may offer an interesting alternative process option to improve gas transfer in the bioleaching reactor and to provide an adequate oxygen supply in order to satisfy the oxygen demand. It might be useful to develop innovative alternative to the classical stirred tank reactor (STR) technology. However, the use of such conditions can lead to much higher dissolved oxygen (DO) concentrations than those encountered with air. Very few papers have been devoted to the study of the optimal range of DO concentrations for bioleaching processes. Most of them reported an inhibitory effect of DO concentrations above 5 ppm. The purpose of this study was to investigate the influence of DO on the bioleaching efficiency under oxygen enriched atmosphere in 21 L stirred tank reactor at 42 degrees C. Bioleaching experiments were performed in continuous mode with sulfide-rich tailings wastes composed mainly of pyrite (51%) and quartz using the "BRGM-KCC" bacterial consortia. The solid load was close to 20% (w/w). Using various oxygen supply conditions (partial pressure, gas rate), the DO concentration in the reactor varied between 4 and 17 ppm. For a DO ranging from 4 to 13 ppm, a good bacterial oxidizing activity was observed and the sulfide dissolution efficiency increased with the DO concentration. It is assumed that this improvement of the bioleaching efficiency was linked to an increase of the oxygen transfer rate from the gas phase to the liquid phase rather than a direct effect of the DO level. When the DO concentration reached 17 ppm a significant decrease of the microbial activity and consequently of the oxygen consumption was noticed. These results show that there is a critical value above which the DO concentration is detrimental to the activity of the bioleach microorganisms present in the "BRGM-KCC" consortia but this value is much higher than the one usually mentioned in the literature. (C) 2016 Elsevier Ltd. All rights reserved.

In bioleaching processes using autotrophic bacteria, CO2 is the carbon source for the growth of the microorganisms and its availability is dependent on gas mass transfer. The objective of this study was to investigate the demand in CO2 in complex copper concentrate bioleaching operations and to optimize CO2 supply. Batch tests in 2L-stirred reactors at 10%w/v solid load were performed to study the need for CO2-supplementation and to determine the adequate CO2 partial pressure in the gas inlet. The results show that Fe oxidation (and thus microbial activity) is delayed when air is injected without CO2-supplementation. CO2-supplementation improves leaching kinetics since Cu dissolution rate increases from 84 mg/L/h with air solely to 120 mg/L/h when CO2 is added to air. The study proposes also a methodology to determine G/L transfer components and to asses CO2 limitations in the system. It shows that the microorganisms are not only sensitive to the transfer rate of CO2 from the gas to the liquid phase, but also to the availability of CO2 in solution.

The Kupferschiefer deposits host the largest known copper reserve in Europe. These black shale type ores are currently exploited in Poland through pyrometallurgical smelting. In Germany exploration campaigns were recently carried out in order to assess and prepare future exploitation of this ore deposit type. The main copper-bearing minerals are: chalcocite, bornite, chalcopyrite and covellite. This type of ore is also characterized by high amounts of carbonate and organic carbon. They can also potentially present high content of arsenic (volatile in pyrometallurgical processes). During the last years, some mining operations in the area face an increased As and C contents, and a lower Cu contents. This phenomenon leads to a lower quality concentrate as well as operating and environmental issues during smelting.

The lack of adequate gas mass transfer is a potential rate limiting step in many bacterial leaching processes. Oxygen can become a limiting factor because of its low solubility compared to the high demand induced by sulfide oxidation. One way of increasing the solubility of oxygen in water or in media solution is by increasing the driving force, i.e. raising the oxygen partial pressure in the gas stream supplied to the leach pulp. The use of oxygen is a well-known practice in high-temperature bioleaching reactors (above 70°C) whereas air is usually preferred in medium and low-temperature operations, mainly for practical and economic reasons in classical CSTR bioleaching condition.Another reason associated with not using enriched oxygen gasis to avoid too high dissolved oxygen concentrations which could impact negatively the bacterial activity. The purpose of this study was to investigate the use of oxygen-enriched gas in bioleaching reactors at 40°C in order to improve the gas transfer in the system when operating at high solid load (20% and more). Bioleaching experiments were performed on a sulfide-rich tailing waste (pyrite 60%) using the “BRGM-KCC” bacterial consortia. The reactor used for the tests was designed on the basis of a new bioleaching reactor concept developed by Air Liquide, Milton Roy Mixing and the BRGM which uses a floating agitator to inject gases, and to mix and suspend solids in the bioleaching solution.Two types of tests were carried out: with air injection and with oxygen enriched gas mix injection.The aim of this work was to confirm the capacity of bacteria to grow and to dissolve pyrite in this type of bioreactors in oxygen-rich atmosphere, and to compare sulfides dissolution rates during the two types of bioleaching tests. The profitability of this new concept of bioreactor will relyon the optimisation of oxygen transfer. The results obtained show that the use of oxygen enriched gas mix does not negatively impact bioleaching performances compared to air injection. High metal extraction yields were achieved (above 80%). No deleterious effect due to oxygen use was observed on the bacteria despite the high level of dissolved oxygen reached in oxygen tests (up to 14 mg.L -1 ). This result is very encouraging in the development of the new type of bioreactorwhere limited gas flows can be combined with high oxygen transfer rates and efficiency.

This paper presents an overview of the work performed by the BRGM team in the last 10 years on the development of bio-hydrometallurgy dedicated to the processing of low-grade copper ores from the Kupferschiefer deposits. It covers selection and adaptation of microbial consortia, optimization of process operating parameters such as solid contents, the relationship between bioleaching performance and mineralogy, testing operating parameters to overcome chalcopyrite recalcitrance, design of process options and economical assessment. The selected bacterial inoculum (autotrophic, working at 42 degrees C) enables to achieve high Cu recovery (up to 95%). In continuous piloting tests the increase of the solid load in the pulp from 15% to 25% doesn't affect the bioleaching efficiency despite the high and unusual Cu concentration reached in the liquor (40 g l(-1)). Operating at 25% solid load reduces by 2.3 the size of the leaching tanks compared to 15% solid load, which leads to a significant decreasing of the CAPEX.

•Overview of Kupferschiefer geology/mineralogy with special emphasis on copper and valuable associate metals.•Bioleaching for metal recovery from Kupferschiefer blackshale (primary and secondary resources).•Discussion of scientific bottlenecks related to the(bio)treatment of blackshale type of ores.•Perspectives in Ecometals project to develop an innovative eco-efficient biohydrometallurgy process.

The consequence of a strong economic growth in emerging countries combined with the rise of the world population is an increase in the demand for raw materials, leading to growing concern regarding their availability and the global efficiency of the supply chain. These tensions reinforce the need to associate the development of the recycling industry to the identification of new resources which could be used for the recovery of valuable materials. The purpose of this study is to develop a novel biological co-processing approach for the recovery of strategic metals in both sulfidic mining wastes and post-consumer wastes (WEEE). The principle of this treatment is based on two steps: mine wastes are biologically oxidized, resulting in the production of a ferric iron-sulfuric acid lixiviant solution which is used to leach base and other soluble metals contained in e-scraps. Batch tests were carried out using flotation tailings wastes containing 60% of pyrite and grinded Printed Circuit Boards (PCB < 750 mu m) with a solid load of 2.5%. Two series of tests were conducted in order to study the influence of the ferric iron concentration and of the bacterial activity on metals dissolution. Results showed that a higher ferric iron concentration led to an increase in the dissolution rate of copper which is the main metal contained in the PCBs. Moreover, a dissolution yield of 98.3% was reached for copper after 2 days when bacterial activity was observed, corresponding to an increase of about 20% compared to the tests without bacterial activity. Finally, this study highlights the importance of the availability of ferric iron and of the bacterial oxidation of ferrous iron for the feasibility of this bioleaching process dealing with the recycling of PCBs. (C) 2015 Elsevier Ltd. All rights reserved.