使用硫的可持續金屬回收.pdf

1、Sustainable metal recovery using sulfurAntoine Allanore Professor of Metallurgy MIT-Materials Science&Engineering allanoremit.eduUpstream low value added inherent to the sector,makes incremental solutions unlikely to mitigate the environmental impact while maintaining the highest standards.Steelshap

2、eSupply chain(1)2$/tmetalMetal(wt%)Upstream low value added inherent to the sector,makes incremental solutions unlikely to mitigate the environmental impact while maintaining the highest standards.SteelshapeSupply chain(1)2$/tmetal1750350052507000020405060100CrTiMnAlFeAlloyLME MetalConcentrateOreCom

3、poundMetal(wt%)SteelshapeProcesses based on hydrometallurgy and organic solvents are the most expensive and questionable from a sustainability standpoint3255075100CapexGlobalWarmingPotentialOther Metal ContentSupply chain(2)Process TechnologyBottleneck Minerals processingCrackingLeachingSolventMiner

4、alogical barrier and energy consumptionTMS 2022Mineralogical barrier and energy consumptionTMS 2022The volume of material handled is larger in aqueous than solid-state separations.Processes converge at low feedstock grades.HIGHER RECOVERYincrease liberation size enhance separationcoarsening partial

5、melting new phasehigh temperaturedensitymagneticsulfides(5.5)vsoxides(7.3)sulfur chemistryMaterials Processing-directions6solid vs melt vs gasHIGHER RECOVERYincrease liberation size enhance separationcoarsening partial melting new phasehigh temperaturehigh temperaturedensitymagneticsulfides(5.5)vsox

6、ides(7.3)sulfur chemistrysulfur chemistrysulfides vsoxidesliquid vs solidMaterials Processing-directions7BETTER SELECTIVITYchange chemistrychange state of mattersolid vs melt vs gasSelective sulfidation flow-sheet8Stinn and Allanore,Nature,2022Mixed Metal OxidesIsolated Metal OxideIsolated Metal Sul

7、fideGasChemPhysicalSulfidation of copper slag(“fayalite”+Cu)Sulfidation of copper slag(“fayalite”+Cu)Caspar Stinn and Antoine Allanore,Allanore Research Group,MIT Slag(sulfidized)qualitative element map:Ca(blue),O(red),S(yellow)Slag(sulfidized)qualitative element map:Cu(green),O(red),S(yellow)Slag(s

8、ulfidized)qualitative element map:Fe(blue),O(red),S(yellow)100 m 100 m Cu enrichmentin sulfidepossible formation of new Cu and Fe sulfides from copper oxide slagSulfidation of bauxiteSulfidation of bauxiteSustainable?-example rare-earth1,000 ktpa100 ktpa10 ktpaOPEX PER TONNE OF FEEDStinn and Allanor

9、e,Nature,2022Sustainable?-example rare-earth1,000 ktpa100 ktpa10 ktpaOPEX PER TONNE OF FEEDHydro.Sulfid.kg CO2eq PER TONNEStinn and Allanore,Nature,2022FeS feedFemolten MxNzS electrolyteS2(g)14FeS Fe+12S2(g)GHG-free production of metal from sulfideSulfides processing in absence of oxygenFeS feedFemo

10、lten MxNzS electrolyteS2(g)14 current flow generates heatFeS Fe+12S2(g)GHG-free production of metal from sulfideSulfides processing in absence of oxygenFeS feedFemolten MxNzS electrolyteS2(g)14 current flow generates heat 66%of energy needed vs oxideFeS Fe+12S2(g)GHG-free production of metal from su

11、lfideSulfides processing in absence of oxygenFeS feedFemolten MxNzS electrolyteS2(g)14 current flow generates heat 66%of energy needed vs oxide proven possible for Cu,Zn,Pb,Au,Ag,Mo,Re,Ni,FeS Fe+12S2(g)GHG-free production of metal from sulfideSulfides processing in absence of oxygenIron production s

12、tage15300g/h scaleHigh Faradaic efficiencyLow cell voltageHigh current densityAbility to produce“hot metal”,i.e.iron with up to 4%CPrior Findings(DOE-AMO,CuFeS2 electrolysis)Sulfur is an extremely efficient mediator for redistribution and new phase growth from natural mineralsThe prior-art at scale

13、shows the path toward energy and cost efficient usage of sulfurSeveral features known to metallurgy(sulfuric acid,power generation,)Opportunity for GHG-free reduction approach,e.g.using electricity.At MIT,we have kilogram scale capabilities,working now on the tonne scale.Duke Ellington/Irving Mills“It does not mean a thing if it aint got that swing”