But also in some 182 pyrometallurgical smelting routes higher levels of electricity use can be possible by replacing fossil fuels with other electricitybased heating technologies e g induction heating 183 In the nick el industry various sources of fossil fuels are used in the production of technicalindustrial gases whichmight be replaced by electricity longer termElectric heating can also be considered as a replacement to the fossil fuel used for heating in auxiliary processes e g boilers and heating Finally in secondary production and more downstream applications electricity might be a viable replacement for some processes using e g natural gas as energy source being replaced by induction heating For higher levels of electrifcation to be viable it will be rele vant that these new processes improve efciency of e xisting fossil fuelbased processes as to ofset possible higher costs of electricity visavis e g natural gas 66 Hydrogen as smelting reducing agent Hydrogen can be considered as a replacement to cok e or natural gasasthe reductant in some pyrometallurgical processes of nonferrous metals or as a reducing agent in the copper fre refning process Hydrogen produced via electrolysis has the beneft of having o xygen as a byproduct which can also be used in some of the smelting processes e g copper smelting This can improve the business case of using electrolysisbased hydrogen as a reducing agent In silicon production research is ongoing to reduce fne grain quartz sand d 5035m in a plasma reactor by means of a suitable reduction agent to produce highpurity solar cell quality silicon metal in a one step process instead of the metallurgical followed by the chemical processes The reduction agent or agents can comprise gases and solid particles and isare typically chosen among hydrocarbon gases particularly methane natural gas hydrogen or a combination of these gases 184 Using hydrogen instead of carbon as reducing agent lik e in steel is not applicable to all metal ores as the reduction process to transform a metal o xide into a metallic form are gov erned by laws of thermodynamics The more G Gibbs constant is high the more difcult is the reaction Constants Gibbs equilibrium K are favourable for reduction by hydrogen of iron ore and are very unfavourable for chromiummanganesesilicon ores as the energy to accomplish the reaction is much higher than to k eep it in equilibrium 185 As with the electrifcation of processes to be viable it will be relevant that hydrogen costs are competitive with carbonbased feedstock s Furthermore hydrogen production itself will 182 For primary copper production this would not apply given that these processes are already e x othermal 183 ICF 2015 184 Euroalliages 185 Sabat et al 2014 has large resources of k aolin clay but aluminasilicate concentration can be low in some places 176 The chlorination and electrolytic reduction of k aolin would replace the current Bayer alumina production and HallH e roult processes The overall process would be 12 46 more efcient and would use smaller cells with the ability to retain temperature and would allow aluminium producers to tak e better advantage of electricity demand response systems 177 The process is still at the early development stages TRL 24 178 Primary copper production via electrolysis Finally a process similar to the HallH e roult process could also be applied to copper pro duction from sulphidebased minerals through a route 179 which selectively separates pure copper and other metallic elements from sulphurbased minerals using molten electrolysis The process is broadly similar to the aluminium HH cell The research found a method of forming liquid copper metal and sulphur from an electrolyte composed of barium sulphide lanthanum sulphide and copper sulphide Electrolysis decomposed sulphurrich minerals into pure sulphur and e xtracted three diferent metals at high purity copper molybdenum and rhenium This onestep process greatly simplifes metal production It yields 99 9 pure copper which is equivalent to the best current copper production methods but without having to undergo multiple energyintense and polluting process stages Furthermore it is more energy efcient 50 energy savings compared to pyrometallurgical route and eliminates to xic byproducts such as sulphur dio xide R esearch is still at early stages and TRL is estimated to be 23 180 65 Further electrifcation of processes While nonferrous metals production is already very electrointensive there still e xists potential for further shifts to replace fossils fuels with electricity In zinc EU production this shift has been outspok en over the past 20 years It is conceivable that in the EU some smelting processes and in particular recycling and metals recovery processes could see a shift over the ne xt decades to the more electrointensive and energyefcient hydrome tallurgical leaching or bioleaching processes This is also due to the decreasing metals concentrations in ores following increased global demand and more difculttorecycle waste streams which might mak e the pyrometallurgical route more energy intensive and less competitive 181 176 European Commission 2017a Flavier et al 2018 177 Fraunhofer ISI 2019 178 Ibidem updated by additional input aluminium technology e xpert 179 P aiste 2018 S tillman H 2018 180 Fraunhofer ISI 2019 181 See Biomore project European Commission ND a and T eck A urubis ND MET ALS IN A CLIMA TE NEUTRAL EUROPE A 2050 BL UEPRINT 55