Abstract: With the world's rapid advancement of technology, the demand and need for the materials that make up that technology has exploded. An important group of materials needed in this rapid advancement are the rare earth elements (REE) used in countless necessary applications. One source of rare earths found in the United States is bastnaesite, a rare earth bearing fluorocarbonate, mined at the Mountain Pass Mine in California. To increase production, it has been essential to optimize existing processes and create new ones to exploit current reserves. This research program was run to expand the understanding of the bastnaesite leaching system. A novel single stage hydrochloric leach system was created to optimize the rare earth extraction from bastnaesite. Typically, this process has utilized a two-stage leach system involving a high temperature hydrochloric acid leach followed by a caustic crack.

Abstract: Disclosed herein is a treated ore solid comprising a reduced amount of a contaminant, for example arsenic, compared to the ore solid prior to treatment. Also disclosed are temperature and pressure modifications, parameters, and methods for treating an ore solid by pressure oxidation leaching of enargite concentrates. The disclosed methods and processes may be applied to copper sulfide orebodies and concentrates containing arsenic. In some cases, the disclosed methods and systems extract, remove, or reduce contaminants, for example arsenic, from an ore containing solution at moderately increased temperature, pressure, and oxygen concentration, and in the presence of an acid.

Abstract: Disclosed herein are methods, techniques, and processes for enhancing the purity of a mixed rare earth solution. In one embodiment the rare earth mixture may include Lanthanum, Cerium, Praseodymium, Neodymium, Promethium, Samarium, Europium, Gadolinium, Terbium, Dysprosium, Holmium, Erbium, Thulium, Ytterbium, Lutetium, Scandium, and/or Yttrium. In one embodiment, the resin is a chelating resin that interacts poorly with one or more rare earth elements. In one embodiment a rare earth is selectively excluded for example, Lanthanum (sometimes considered a transition metal), Cerium, Praseodymium, Neodymium, Promethium, Samarium, Europium, Gadolinium, Terbium, Dysprosium, Holmium, Erbium, Thulium, Ytterbium, Lutetium, Scandium, and/or Yttrium. In one embodiment, yttrium is selectively excluded from the column.

Abstract: Disclosed herein are methods and systems for recovery of ancylite, a rare earth mineral comprising strontium carbonate, from rare earth ore. In many embodiments, the disclosed methods and systems provide for recovery of greater than 50% of the ancylite from an ancylite containing ore. In many embodiments, the ore is subjected to flotation in the presence of an acid, for example a hydroxamic acid, such as octanohydroxamic acid. The ore may also be subjected to magnetic separation, for example wet high intensity magnetic separation.

Abstract: A system and method for decoating a scrap coated metal in a leach solution uses direct measuring of the corrosion potential of the scrap metal in the system to determine the progress of the decoating process and end the process when the scrap is decoated. Corrosion potential measurements are made using a working electrode comprising more than one piece of scrap coated-metal within the system. The decoating system and method may include a system for recycling leach solution.

Abstract: Disclosed herein are methods and systems for recovery of ancylite, a rare earth mineral comprising strontium carbonate, from rare earth ore. In many embodiments, the disclosed methods and systems provide for recovery of greater than 50% of the ancylite from an ancylite containing ore. In many embodiments, the ore is subjected to flotation in the presence of an acid, for example a hydroxamic acid, such as octanohydroxamic acid. The ore may also be subjected to magnetic separation, for example wet high intensity magnetic separation.

Abstract: Oxine ligands placed on styrene base ion exchange resins selectively remove iron and gallium from acidic solutions. After loading, the oxine resin is stripped of the loaded metals and used again for further metal removal. The resins can be used for process streams, acid rock drainages, or any other iron or gallium containing solution.

Abstract: A system and method for decoating a scrap coated metal in a leach solution uses direct measuring of the corrosion potential of the scrap metal in the system to determine the progress of the decoating process and end the process when the scrap is decoated. Corrosion potential measurements are made using a working electrode comprising more than one piece of scrap coated-metal within the system. The decoating system and method may include a system for recycling leach solution.

Abstract: Disclosed herein are methods, techniques, and processes for enhancing the purity of a mixed rare earth solution. In one embodiment the rare earth mixture may include Lanthanum, Cerium, Praseodymium, Neodymium, Promethium, Samarium, Europium, Gadolinium, Terbium, Dysprosium, Holmium, Erbium, Thulium, Ytterbium, Lutetium, Scandium, and/or Yttrium. In one embodiment, the resin is a chelating resin that interacts poorly with one or more rare earth elements. In one embodiment a rare earth is selectively excluded for example, Lanthanum (sometimes considered a transition metal), Cerium, Praseodymium, Neodymium, Promethium, Samarium, Europium, Gadolinium, Terbium, Dysprosium, Holmium, Erbium, Thulium, Ytterbium, Lutetium, Scandium, and/or Yttrium. In one embodiment, yttrium is selectively excluded from the column.

Abstract: Disclosed herein is a treated ore solid comprising a reduced amount of a contaminant, for example arsenic, compared to the ore solid prior to treatment. Also disclosed are temperature and pressure modifications, parameters, and methods for treating an ore solid by pressure oxidation leaching of enargite concentrates. The disclosed methods and processes may be applied to copper sulfide orebodies and concentrates containing arsenic. In some cases, the disclosed methods and systems extract, remove, or reduce contaminants, for example arsenic, from an ore containing solution at moderately increased temperature, pressure, and oxygen concentration, and in the presence of an acid.

Abstract: Oxine ligands placed on styrene base ion exchange resins selectively remove iron and gallium from acidic solutions. After loading, the oxine resin is stripped of the loaded metals and used again for further metal removal. The resins can be used for process streams, acid rock drainages, or any other iron or gallium containing solution.

Abstract: An antimony recovery process is disclosed in which antimony-containing material is leached in a solvent including elemental sulfur and a caustic to preferentially leach antimony. The antimony-containing leach liquor from the leaching step is separated from the insoluble residue by filtration, and the antimony compounds in the separated leach liquor are crystallized to separate the antimony compounds from impurities which are left in solution in the leach liquor. The crystals are then redissolved and treated to create marketable antimony products of high purity, such as antimony metal, sodium hydroxy antimonate, sodium antimonate, antimony pentoxide, and antimony pentasulfide. Alternatively, the crystallized antimony compounds comprising primarily sodium thioantimonate crystals may be recovered and sold without further treatment. Waste products may be treated with soluble iron compounds and lime to render the waste products safe for disposal.

Abstract: A process for extracting silver, copper, zinc, arsenic and iron from sulfide materials by leaching under relatively mild oxygen pressure and temperature conditions with sulfuric acid and sodium nitrite.