New Industrial Process for Electrowinning of Nd-Fe
                                                Alloy

Tamamura, Hideo

doi:10.1149/199017.0611pv

Cited by 10 publications

(6 citation statements)

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“…In addition, depending on the replacement rate of LiF-NdF -Nd O and the Nd 2 O 3 solubility in the electrolyte, other fluorine emissions occur. Under conditions of positive oxidizing atmosphere, the F reacts with the water contained in the cell forming HF (reaction 15) [18,27].The theoretical decomposition of Nd fluoride and H O producing HF [17] is presented (reaction 16) below:…”

Section: Anode Effects and Pfc Emissionsmentioning

confidence: 99%

Rare Earth Electrolysis: key issues for measurement of greenhouse gases from oxide-fluoride systems

Fukurozaki¹,

Landgraf²

2021

Preprint

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Over the past decade, the reduction of greenhouse gases (GHG) has been recognized as one of the key factors for sustainable primary metal production, in which the rare earth (RE) industry can be affected both in terms of price and use by GHG reduction policies and nontariff technical barriers. From environmental and economic standpoint, the perfluorocarbons (PFC) emissions generated in RE electrolysis during events known as anode effects (AE) are strong infrared-absorbing GHG and play an important role for RE metals process improvements. However, there is no standard methodology to account these GHG emissions from RE metal production industry and the assessment of the contribution of PFC emissions from different technologies to the global warming is urgently needed. This paper focuses on the analysis of PFC measurements from RE metal production in terms of GHG inventory and sustainable production. The state of art of RE fused oxide-fluoride electrolysis, particularly of neodymium electrolysis, provides the technical fundamentals for the evaluation of PFC emissions factors reported in scientific articles. Based on International Panel on Climate Change (IPCC) standard methods and US Environmental Protection Agency (EPA) and International Aluminium Institute (IAI) protocol applied to analogous industrial process, the analysis of key issues for estimate CF4 and C2F6 emission factors from electrolytic RE production indicates the additional refinements are necessary to optimize the accuracy of total PFC emission amount from each currently RE technology. Additionally, the selection of emission estimation technique (EET) or mix EET should be considered on case-by-case basis as to their purposes and suitability for a particular process and facility. Finally, this paper highlights the technological implications related to the PFC emissions measurements and trends towards to set goals and develop strategies for GHG mitigation.

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Section: Anode Effects and Pfc Emissionsmentioning

confidence: 99%

Rare Earth Electrolysis: key issues for measurement of greenhouse gases from oxide-fluoride systems

Fukurozaki¹,

Landgraf²

2021

Preprint

View full text Add to dashboard Cite

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“…In addition, depending on the replacement rate of LiF-NdF 3 -Nd 2 O 3 and the Nd 2 O 3 solubility in the electrolyte, other uorine emissions occur. Under conditions of positive oxidizing atmosphere, the F reacts with the water contained in the cell forming HF (reaction 15) [18,27].The theoretical decomposition of Nd uoride and H 2 O producing HF [17] is presented (reaction 16) below:…”

Section: Anode Effects and Pfc Emissionsmentioning

confidence: 99%

Rare Earth Electrolysis: key issues for measurement of greenhouse gases from oxide-fluoride systems

Fukurozaki¹,

Landgraf

2021

Preprint

View full text Add to dashboard Cite

Over the past decade, the reduction of greenhouse gases (GHG) has been recognized as one of the key factors for sustainable primary metal production, in which the rare earth (RE) industry can be affected both in terms of price and use by GHG reduction policies and non-tariff technical barriers. From environmental and economic standpoint, the perfluorocarbons (PFC) emissions generated in RE electrolysis during events known as anode effects (AE) are strong infrared-absorbing GHG and play an important role for RE metals process improvements. However, there is no standard methodology to account these GHG emissions from RE metal production industry and the assessment of the contribution of PFC emissions from different technologies to the global warming is urgently needed. This paper focuses on the analysis of PFC measurements from RE metal production in terms of GHG inventory and sustainable production. The state of art of RE fused oxide-fluoride electrolysis, particularly of neodymium electrolysis, provides the technical fundamentals for the evaluation of PFC emissions factors reported in scientific articles. Based on International Panel on Climate Change (IPCC) standard methods and US Environmental Protection Agency (EPA) and International Aluminium Institute (IAI) protocol applied to analogous industrial process, the analysis of key issues for estimate CF4 and C2F6 emission factors from electrolytic RE production indicates the additional refinements are necessary to optimize the accuracy of total PFC emission amount from each currently RE technology. Additionally, the selection of emission estimation technique (EET) or mix EET should be considered on case-by-case basis as to their purposes and suitability for a particular process and facility. Finally, this paper highlights the technological implications related to the PFC emissions measurements and trends towards to set goals and develop strategies for GHG mitigation.

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“…Studies by Tamamura et al8 and Kaneko et al9 suggest that the source of Nd is [NdF 6 ] 32 at high current densities and [NdOF 5 ] 42 at low current densities. To clarify the role of oxyfluoride ions, the reactions in the electrolysis of Al and Nb from oxyfluoride melts are discussed briefly.That is, the oxyfluoroaluminate ions formed by the addition of Al 2 O 3 to cryolite is involved in the anodic reaction, and not the deposition of aluminium.In fluoride niobium bearing melts [NbF 7 ] 22 is the dominant complex, while [NbOF 6 ] 32 prevails in oxyfluoride melts,7 the equilibrium reaction being 3 NbF 7 ½ 2{ zNb 2 O 5 z9F { ~5 NbOF 6 ½ 3{…”

mentioning

confidence: 99%

Molten salt electrolysis of neodymium: electrolyte selection and deposition mechanism

Thudum

Srivastav

Nandi

et al. 2010

Mineral Processing and Extractive Metallurgy

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Molten salt electrolysis of neodymium from Nd 2 O 3 can be a viable alternative to calciothermic reduction. Two important issues merit attention: selection of an appropriate electrolyte and the mechanism of the neodymium deposition reaction. Cyclic voltammetry experiments and melting point considerations point to the eutectic LiF-CaF 2 as an appropriate electrolyte. The presence of CaF 2 polarises the Li deposition reaction to more cathodic potentials, thereby providing a larger potential window for the deposition of neodymium. Experiments with the LiF-CaF 2 -NdF 3 -Nd 2 O 3 and LiF-CaF 2 -LaF 3 -Nd 2 O 3 melts suggest that both [NdF 6 ] 32 and [NdOF 5 ] 42 , depending on their molar ratios, can be reduced to neodymium.

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New Industrial Process for Electrowinning of Nd-Fe Alloy

Cited by 10 publications

References 0 publications

Rare Earth Electrolysis: key issues for measurement of greenhouse gases from oxide-fluoride systems

Rare Earth Electrolysis: key issues for measurement of greenhouse gases from oxide-fluoride systems

Rare Earth Electrolysis: key issues for measurement of greenhouse gases from oxide-fluoride systems

Molten salt electrolysis of neodymium: electrolyte selection and deposition mechanism

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