Engineering topics

Baek, Donna L.

Publications and source records attributed to Baek, Donna L..

5 records

DOE OSTI2023

Methods of recovering an elemental rare earth metal, and methods of forming a rare earth metal

A method of recovering an elemental rare earth metal comprises placing a rare earth-containing material comprising a rare earth metal in a reaction solution comprising a reducing agent and a non-aqueous solvent comprising an ionic liquid or a eutectic mixture, reducing the rare earth metal with the reducing agent to form a metallic rare earth metal and cations of the reducing agent, transferring the cations of the reducing agent from the reaction solution to an electrochemical cell through an ion exchange membrane, and reducing the cations of the reducing agent in the electrochemical cell. Related methods of forming an elemental rare earth metal, and related systems are disclosed.

Case, Mary E.↗

DOE OSTI2022

Molten salt electrolysis and room temperature ionic liquid electrochemical processes for refining rare earth metals: Environmental and economic performance comparison

Circularizing end of life products such as electronic waste can open a new source for rare earth elements (REEs) that will decrease the demand pressure on conventional virgin production. The last step to produce REEs consists of a refining process to convert rare earth oxide (REO) to REE metal. One promising technology is processing REO via a room temperature ionic liquid, which is characterized by low energy requirements in contrast to existing REEs extraction processes. In this work, life cycle and techno-economic assessments are performed and compared against molten salt electrolysis. Here, the results show that both processes have advantages and disadvantages in terms of environmental performance, and that they are similarly competitive in terms of economic performance. A breakeven analysis suggests that future research should focus on coupling the production of REOs with the refining processes to attempt to lower REO cost and make them economically feasible in the U.S.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2022

Studies toward the Use of Ionic Liquids and Supercritical CO 2 for the Recovery and Separation of Praseodymium from Waste Streams

Waste streams from the incineration of metal-containing materials like such as computer processor boards and batteries may contain critical rare earth elements like praseodymium. Data on the solubility of Pr compounds and on their distribution coefficients in supercritical CO 2 /ionic liquid two-phase systems are important to determine if an ionic liquid/supercritical CO 2 two-phase approach is feasible toward the recovery of a particular metal. This work provides data on the solubility of various praseodymium compounds in butyl-methyl-pyrrolidinium bis(trifluoromethylsulfonyl)imide (BMPyTf2N) ionic liquid and on the distribution coefficients of these praseodymium compounds in the supercritical CO 2 phase of the two-phase BMPyTf2N ionic liquid/supercritical CO 2 system, with and without a tributyl phosphate additive.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2022

Electrochemical, thermodynamic, and physical properties of tetradecyltrihexylphosphonium ([P 6,6, 6,14 ] + ) and methyl-propyl piperidinium containing ionic liquids and their propylene carbonate solutions

Here, the viscosity, conductivity, electrochemical window and related thermodynamic properties such as excess volume and dynamic viscosity deviation of two phosphonium ionic liquids were measured and calculated for “as-supplied” and dried neat liquids and also v/v mixtures of 99/1, 95/5, 90/10, 75/25, and 50/50 of the ionic liquids with propylene carbonate (PC). Tetradecyltrihexylphosphonium dicyanamide ([P 6,6,6,14 ] + dicyanamide), Cyphos 105, and tetradecyltrihexylphosphonium bis(trifluororomethanesulfonyl)imide (called bistriflimide) ([P 6,6,6,14 ] + bistriflimide), Cyphos 109, ionic liquids were studied. Generally speaking, there were slight differences in the measured properties of the wet and dried IL solutions which were reflected in differences if the calculated properties. The measured and calculated properties were compared with those collected and derived from a piperidinium-based ionic liquid, methyl-propyl piperidinium bistriflimide. Arrhenius plots for both the viscosity and conductivity were linear, with the linearity of the Litovitz plots being slightly higher. The viscosity and conductivity of the phosphonium solutions yielded Walden Plots that differed from Walden plots of piperidinium solutions and other ionic liquid solutions. For the phosphonium based ionic liquids, the ionicity was found to increase with increasing dilution in propylene carbonate. The electrochemical windows of the ionic liquids were determined as a function of the concentration of the ionic liquid present in the solution. The size of the window generally initially decreased and then increased with the addition of PC for the [P 6,6,6,14 ] + dicyanamide ionic liquid increasing from 3.4 V in the 95/5 v/v (volume Cyphos 105) to volume of PC solvent) to 3.7 in the 50/50 dried IL case. The electrochemical windows of the dried liquids were slightly larger 3.5 V for the 95/5 v/v and 4.2 V for the 50/50 v/v Cyphos 105/PC solutions. The electrochemical window was larger and the conductivity was higher for the piperidinium IL solutions, but since the ionicity increases with dilution, the phosphonium based IL solutions may prove favorable for processes such as electrochemical reduction.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2021

Methods of forming metals using ionic liquids

A method of forming an elemental metal (e.g., a rare-earth element) includes forming a multicomponent solution comprising an ionic liquid, a secondary component, and a metal-containing compound. The multicomponent solution is contacted with at least a first electrode and a second electrode. A current is passed between the first electrode to the second electrode through the multicomponent solution. The metal-containing compound is reduced to deposit the elemental metal therefrom on the first electrode.

Baek, Donna L.↗