Abstract: Disclosed herein are methods, devices, and systems for effectively separating carbonate gangue from bastnaesite without sacrificing significant REO grade or recovery. In some embodiments, centrifugal concentrators may beneficiate Ultra-Fine (UF) bastnaesite and calcite bearing flotation concentrates. The disclosed methods, devices, and systems can achieve initial gravity REO recoveries exceeding 90% while rejecting on the order of 25% to 35% of the total calcium from an assortment of rougher and cleaner flotation concentrates. Addition of stages of cleaner UF Falcon gravity separation may be operated in an open circuit configuration, from an original fine feed of 35 microns containing 50.5% REO and 5.5% Ca, to upgrade up to approximately 59% REO and 2.0% calcium.

Abstract: Rechargeable metal-air battery, air electrodes for use in the metal-air battery, and methods to manufacture the same are provided. The battery includes a negative electrode capable of taking and releasing active metal ions, a porous positive electrode using oxygen as an electroactive material and an electrolyte configured to conduct ions between the negative and positive electrodes and comprising one or more phases, wherein at least one phase comprises a liquid that at least partially fills the pores of the positive electrode and wherein the liquid comprises an oxygen evolving catalyst (OEC). The OEC a) is soluble in the liquid of the phase that partially fills the positive electrode pores, b) is electrochemically activated at a potential above the equilibrium cell voltage and c) is capable of evolving oxygen gas by oxidizing a metal oxide discharge product produced during discharge of the rechargeable metal-air battery.

Abstract: High energy rechargeable batteries employing catalyzed molten nitrate positive electrodes and alkali metal negative electrodes are disclosed. Novel and advantageous aspects of the present invention are enabled by the provision catalytically active materials that support the reversible formation of NO3? from O2? and NO2? during battery charging. Such catalytically active materials allow highly efficient cycling and selectively eliminate irreversible side reactions that occur when cycling without such catalysts.

Abstract: High energy rechargeable batteries employing catalyzed molten nitrate positive electrodes and alkali metal negative electrodes are disclosed. Novel and advantageous aspects of the present invention are enabled by the provision catalytically active materials that support the reversible formation of NO3? from O2? and N02? during battery charging. Such catalytically active materials allow highly efficient cycling and selectively eliminate irreversible side reactions that occur when cycling without such catalysts.

Abstract: Rechargeable metal-air battery, air electrodes for use in the metal-air battery, and methods to manufacture the same are provided. The battery includes a negative electrode capable of taking and releasing active metal ions, a porous positive electrode using oxygen as an electroactive material and an electrolyte configured to conduct ions between the negative and positive electrodes and comprising one or more phases, wherein at least one phase comprises a liquid that at least partially fills the pores of the positive electrode and wherein the liquid comprises an oxygen evolving catalyst (OEC). The OEC a) is soluble in the liquid of the phase that partially fills the positive electrode pores, b) is electrochemically activated at a potential above the equilibrium cell voltage and c) is capable of evolving oxygen gas by oxidizing a metal oxide discharge product produced during discharge of the rechargeable metal-air battery.