Environmental impacts of processing secondary cobalt raw materials

Riina Aromaa-Stubb

Environmental impacts of processing secondary cobalt raw materials

Julkaisun otsikon käännös: Sekundääristen kobolttiraaka-aineiden prosessoinnin ympäristövaikutukset

Riina Aromaa-Stubb

Kemian tekniikan ja metallurgian laitos

Tutkimustuotos: Doctoral Thesis › Collection of Articles

Abstrakti

Koboltin kysynnän on ennustettu kasvavan tulevina vuosikymmeninä. Nykyisellään lähes kaikki koboltti tuotetaan primääriraaka-aineista ja sen tuotanto on keskittynyt maantieteellisesti harvoille alueille. Tuotantoon liittyy myös ympäristövaikutuksia sekä huolta toiminnan kestävyydestä. Kierrätysraaka-aineiden käytön lisääminen koboltin tuotannossa on käytännössä välttämätöntä ja sen avulla voidaan myös parantaa raaka-ainesaatavuutta sekä laskea tuotannon ympäristövaikutuksia. Tämän väitöskirjan tutkimuksen tavoitteena on arvioida koboltin kierrätyksen ympäristövaikutuksia, kun raaka-aineina käytetään kovametallia ja kobolttikatalyyttejä. Tutkimuksessa käytettiin tutkimusmenetelmänä prosessimallinukseen perustuvaa elinkaariarviointia (LCA). Tutkittavat prosessit mallinnettiin HSC Sim -ohjelmalla kirjallisuudesta saatujen prosessitietojen ja -arvojen avulla. Kierrätysprosessimallin perusteella voitiin rakentaa inventaario, joka sisältää numeraalisina arvoina sekä prosessin suorat päästöt että käytettyjen kemikaalien ja hyödykkeiden kulutuksen. Tämänkaltainen inventaario mahdollistaa kehitteillä olevien prosessien ennakoivan ympäristövaikutusten arvioinnin. Ympäristövaikutukset laskettiin GaBi tai openLCA -ohjelmalla ja taustaprosessien (kuten käytettyjen kemikaalien ja sähkön tuotanto) arvoina käytettiin ecoinvent-tietokannan arvoja. Tulosten tulkinnassa sekä johtopäätösten ja suositusten määrityksessä käytettiin erilaisia kontribuutio-, skenaario-, herkkyys-, ja epävarmuusanalyysejä. Tutkituissa kierrätysprosesseissa arvioitiin yhteensä yhdeksän prosessiskenaariota. Viisi kierrätysprosessia keskittyi kovametallin kierrätykseen ja näistä kolme volframin ja koboltin kierrätykseen, kun taas kaksi tantaalin ja niobiumin kierrätykseen. Lisäksi tutkittiin neljää katalyyttien kierrätysprosessia. Kolme tutkittua prosessia keskittyi koboltin kierrätykseen Fischer-Tropsch-katalyytistä ja yksi molybdeenin, vanadiinin, nikkelin ja koboltin kierrätykseen Mo/Co/γ-Al2O3-katalyytistä. Kaikissa skenaarioissa - tantaalin ja niobiumin kierrätystä lukuun ottamatta - kierrätysprosessien ympäristövaikutukset olivat pienemmät kuin samojen tuotteiden ympäristövaikutukset olisivat valmistettaessa primääriraaka-aineista. Tutkimuksessa käytettävällä prosessimallinnuksella kerätyt lähtötiedot ovat toissijaista, ja niillä on korkeampi epävarmuus kuin ensisijaisesti suoraan laitokselta kerätyillä massa- ja energiatase tiedoilla ja arvoilla. Tässä tutkimuksessa käytettiin useita herkkyys- ja epävarmuusanalyysimetodeja arvioimaan, miten mallinnettuun dataan liittyvä epävarmuus vaikuttaa tulosten perusteella määritettyihin johtopäätöksiin ja suosituksiin. Nämä analyysit tehtiin sekä suoraan elinkaariarvion mallin inventaariolle, kuten kemikaalien kulutukselle, että prosessimallinnuksen parametreille, jotka vaikuttavat inventaarion muodostumiseen. Prosessimallinnuksen parametreilla, jotka liittyivät kemikaalien ja hyödykkeiden kulutukseen tulokset olivat samankaltaisia inventaarion analyysien tulosten kanssa, kun taas suoriin päästöihin liittyvillä parametreilla erot olivat suurempia.

Julkaisun otsikon käännös	Sekundääristen kobolttiraaka-aineiden prosessoinnin ympäristövaikutukset
Alkuperäiskieli	Englanti
Pätevyys	Tohtorintutkinto
Myöntävä instituutio	Aalto-yliopisto
Ohjaaja	Lundström, Mari, Vastuuprofessori Rinne, Marja, Ohjaaja
Kustantaja	Aalto University
Painoksen ISBN	978-952-64-2799-7
Sähköinen ISBN	978-952-64-2798-0
Tila	Julkaistu - 2025
OKM-julkaisutyyppi	G5 Artikkeliväitöskirja

Tutkimusalat

prosessimallinnus
ympäristövaikutukset
kovametallin kierrätys
katalyyttien kierrätys

Pääsy asiakirjaan

http://urn.fi/URN:ISBN:978-952-64-2798-0

Raaka-aineiden tutkimusinfrastruktuuri
Karppinen, M. (Manager)
Kemian tekniikan korkeakoulu
Laitteistot/tilat: Facility

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title = "Environmental impacts of processing secondary cobalt raw materials",

abstract = "The demand for cobalt is predicted to continue growing in the next decades and is currently being supplied practically entirely by primary production, which is highly concentrated geographically and raises environmental concerns. Increasing the supply of cobalt from secondary raw materials is necessary to meet the growing demand and can help diversify the supply and lower the environmental impacts of cobalt production. The goal of this thesis was to assess the environmental impacts of cobalt recycling from hard metal scrap and spent cobalt catalysts. The methodology used in this study was simulation-based life cycle assessment (LCA). The studied processes were simulated with HSC Sim software based on information and values from the literature to gather an inventory of direct emissions and consumed chemicals and utilities. This allows for investigation of the environmental impacts of pro-cesses still in the development stage. The environmental impacts were calculated in GaBi or openLCA software using the ecoinvent database for the background data, such as the production of the chemicals and electricity consumed. Contribution, scenario, sensitivity and uncertainty analyses were used in the interpretation phase to formulate the conclusions and recommendations. In total nine scenarios were assessed in this work. Five recycling scenarios examined hard metal recycling with three focusing on tungsten and cobalt recycling and two on tantalum and niobium recycling. In addition, four catalyst recycling scenarios were investigated. Three were focused on cobalt recycling from a Fischer-Tropsch catalyst, and one on molybdenum, vanadium, nickel and cobalt recycling from a Mo/Co/γ-Al2O3 catalyst. All scenarios apart from the tantalum and niobium recycling scenarios showed that the environmental impacts of the recycling systems were lower than those of primary production of the same products. Data produced by process simulation is considered secondary data, which has a higher uncertainty than primary data measured directly from a plant. This study used several methods of sensitivity and uncertainty analysis to estimate the effect of data uncertainty on the conclusions and recommendations formulated based on process simulation data. The analyses were performed both directly on the inventory items of the LCA model, such as the consumption of chemicals, and the process simulation parameters that affected the formation of the inventory. For the process simulation parameters related to the consumption of chemicals and utilities the results were similar to the results of the analyses focused on the inventory, while the parameters related to direct emissions showed a larger difference between the analyses.",

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N2 - The demand for cobalt is predicted to continue growing in the next decades and is currently being supplied practically entirely by primary production, which is highly concentrated geographically and raises environmental concerns. Increasing the supply of cobalt from secondary raw materials is necessary to meet the growing demand and can help diversify the supply and lower the environmental impacts of cobalt production. The goal of this thesis was to assess the environmental impacts of cobalt recycling from hard metal scrap and spent cobalt catalysts. The methodology used in this study was simulation-based life cycle assessment (LCA). The studied processes were simulated with HSC Sim software based on information and values from the literature to gather an inventory of direct emissions and consumed chemicals and utilities. This allows for investigation of the environmental impacts of pro-cesses still in the development stage. The environmental impacts were calculated in GaBi or openLCA software using the ecoinvent database for the background data, such as the production of the chemicals and electricity consumed. Contribution, scenario, sensitivity and uncertainty analyses were used in the interpretation phase to formulate the conclusions and recommendations. In total nine scenarios were assessed in this work. Five recycling scenarios examined hard metal recycling with three focusing on tungsten and cobalt recycling and two on tantalum and niobium recycling. In addition, four catalyst recycling scenarios were investigated. Three were focused on cobalt recycling from a Fischer-Tropsch catalyst, and one on molybdenum, vanadium, nickel and cobalt recycling from a Mo/Co/γ-Al2O3 catalyst. All scenarios apart from the tantalum and niobium recycling scenarios showed that the environmental impacts of the recycling systems were lower than those of primary production of the same products. Data produced by process simulation is considered secondary data, which has a higher uncertainty than primary data measured directly from a plant. This study used several methods of sensitivity and uncertainty analysis to estimate the effect of data uncertainty on the conclusions and recommendations formulated based on process simulation data. The analyses were performed both directly on the inventory items of the LCA model, such as the consumption of chemicals, and the process simulation parameters that affected the formation of the inventory. For the process simulation parameters related to the consumption of chemicals and utilities the results were similar to the results of the analyses focused on the inventory, while the parameters related to direct emissions showed a larger difference between the analyses.

AB - The demand for cobalt is predicted to continue growing in the next decades and is currently being supplied practically entirely by primary production, which is highly concentrated geographically and raises environmental concerns. Increasing the supply of cobalt from secondary raw materials is necessary to meet the growing demand and can help diversify the supply and lower the environmental impacts of cobalt production. The goal of this thesis was to assess the environmental impacts of cobalt recycling from hard metal scrap and spent cobalt catalysts. The methodology used in this study was simulation-based life cycle assessment (LCA). The studied processes were simulated with HSC Sim software based on information and values from the literature to gather an inventory of direct emissions and consumed chemicals and utilities. This allows for investigation of the environmental impacts of pro-cesses still in the development stage. The environmental impacts were calculated in GaBi or openLCA software using the ecoinvent database for the background data, such as the production of the chemicals and electricity consumed. Contribution, scenario, sensitivity and uncertainty analyses were used in the interpretation phase to formulate the conclusions and recommendations. In total nine scenarios were assessed in this work. Five recycling scenarios examined hard metal recycling with three focusing on tungsten and cobalt recycling and two on tantalum and niobium recycling. In addition, four catalyst recycling scenarios were investigated. Three were focused on cobalt recycling from a Fischer-Tropsch catalyst, and one on molybdenum, vanadium, nickel and cobalt recycling from a Mo/Co/γ-Al2O3 catalyst. All scenarios apart from the tantalum and niobium recycling scenarios showed that the environmental impacts of the recycling systems were lower than those of primary production of the same products. Data produced by process simulation is considered secondary data, which has a higher uncertainty than primary data measured directly from a plant. This study used several methods of sensitivity and uncertainty analysis to estimate the effect of data uncertainty on the conclusions and recommendations formulated based on process simulation data. The analyses were performed both directly on the inventory items of the LCA model, such as the consumption of chemicals, and the process simulation parameters that affected the formation of the inventory. For the process simulation parameters related to the consumption of chemicals and utilities the results were similar to the results of the analyses focused on the inventory, while the parameters related to direct emissions showed a larger difference between the analyses.

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KW - environmental impacts

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KW - hard metal recycling

KW - catalyst recycling

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Environmental impacts of processing secondary cobalt raw materials

Abstrakti

Tutkimusalat

Pääsy asiakirjaan

Sormenjälki

Laitteet

Raaka-aineiden tutkimusinfrastruktuuri

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