The total estimate mark et value of these additionally recovered metals would be around EUR 29 Bn per year With current technologies and new pyrometallurgical methods the recovery of additional metals from residues requires energy intensive smelting and fuming processes Further more these processes will have to avoid direct and indirect CO 2 emissions 207 Indirect emissions can be avoided by using more carbonfree electricity In addition process emis sions will be released in the fuming of metals from the waste streams due to the use of re ducing agents such as coal The slag obtained after fuming can be used in other industries e g as construction material in particular if environmentally hazardous substances such as arsenic have been removed This would limit or avoid landflling A voiding or reducing CO 2 emissions in fuming and smelting processes would require technologies and techniques as mentioned before For instance the use of biobased fuels andor reducing agents hydrogen andor CCUS However investment costs can be large and higher operational e xpenditure might hamper largescale application Other new technologies that can help bring about a higher recovery rate of the abovemen tioned metals from lowgrade ore and waste streams include 208 A tmo spheric acid leaching TRL 34 TRL 2 for ferronick el slag 209 Heap leaching TRL 34 TRL 23 for ferronick el slag 210 A utotrophic bioleachin g TRL 23 211 Heterotrophic bioleaching TRL 2 212 Solvometallurgical leaching TRL 24 213 Io nometallurgic al e x ctraction TRL 34 214 Plasmapy ro technology TRL 34 215 Most of the abovementioned technological option are still at low TRL and will require further research and investments to allow upscaling to pilot and demonstration stages 207 Salminen J and Olaussen S2018 208 Metgrow 2018 209 A tmospheric acid leaching refers to hydrometallurgical processes that utilize nonpressurized stirred reactor appl ications with temperatures 100 C For application to laterite ores and ferronick el slag 210 Heap leaching is a controlled process whereby a comple x or lowgrade ore is stack ed in short lifts usually crushed and often agglomerated on a carefully prepared containment system the leach pad and irrigated in a controlled manner with a solution to e xtract the optimum amount of metal from the material For application to laterite ores ferronick el slag landflled chromiumrich sludge jarosite landflled zincrich sludge and Goethite 211 A utotrophic o xidative and reductive bioleaching refers to biohydrometallurgical methods which rely on bacterial activity to o xidizereduce diferent sulfur and iron species This results in production of leaching agent sulfuric acid o xidant ferric iron or reduction of iron enabling enhanced leaching of certain o xidized minerals For application to laterite ores Jarosite landflled zincrich sludges goethite fayalitic slags 212 Heterotrophic bioleaching involves the production of diverse biogenic lixiviants via microbial yeast fungi and bac teria respiration using organic carbon For application to landflled chromiumrich sludge jarosite landflled zincrich sludge fayalitic slag steel sludge and automotive shredder residue 213 Solvometallurgical leaching consists of applying organic liquids solvents e xtractants organic acids modifers to e xtract metals from a solid source The aim is to reduce the volume of the aqueous phase 50 compared to conventional leaching For application to laterite ores jarosite landflled chromium and zincrich sludge Ggoethite and steel sludge 214 Solvent leaching using Deep Eutectic Solvents DESs which are eutectic mixtures of L ewis or Bronsted acids and bases For application to laterite ores Jarosite landflled zincrich sludge fayalitic slag and steel sludge 215 A pyrometallurgical route to preconcentrate diferent type of materials For application to jarosite landflled zincrich sludge goethite and fayalitic slag Process to 913 It s TRL is estimated to be 7 202 More importantly the process converts a hazardous waste into two viable coproducts also preventing accidental discharge into the environment e g rivers marine or ground water This technology would also ofer a solution for cleaningup legacy redmud 203 Other technologies in development to treat red mud with the goal to e xtract valuable mate rials and metals include 204 L eaching of rare earth elements from red mud TRL 5 R ecovery of titanium dio xide and aluminium o xide through microwave roasting of baux ite residue and inorganic cement binder production TRL 4 Scandium e xtraction from bauxite residue TRL 7 Inorganic polymers from bauxite residue TRL 6 Production of iron alloy TRL 6 Enhanced metals recovery from low grade ores landflled sludges and slags Ne xt to the recovery of valuable metals and other products from bauxite residue waste streams from other nonferrous mining and production can result in large quantities of additional metals production in the EU The combination of enhanced metals recovery from lowgrade ores e g laterite fne grained landflled sludges iron rich sludges from metals production e g Jarosite sludge from zinc production 205 and fayalitic slag mostly from primary and secondary copper production can bring about the following additional annual metals production in the EU 206 129 000 t Zinc 49 000 t lead 38000 t nick el 36000 t chromium 27 000 t copper 1400 t cobalt 13 of current EU demand 225 t antimony 28 of current EU demand 78 t gallium 29 of current EU de mand 58 t indium 77 of current EU demand and 31 t germanium 15 of current EU demand 202 Ibidem EN EX AL project FP720102014 estimates TRL 7 203 Fraunhofer ISI 2019 204 EU MSC AETN REDMUD 2018 205 Jarosite contains for e xample Fe 15 wt Zn 23 wt Pb 3 wt A g In Ga Ge in ppm levels and A u less than 1 ppm 206 The sources considered here are P olish laterite Greek laterite FeNi slag landflled Crrich sludge Jarosite landflled Znrich sludge Goethite fayalitic slag steel sludge and automotive shredder residue MET GRO W ND MET ALS IN A CLIMA TE NEUTRAL EUROPE A 2050 BL UEPRINT 58