Rare Earths Occurrence in Florida Phosphate Ore and Their Fate during Mining and Chemical Processing

Phosphate minerals have been identified as significant unconventional rare earths resources. World’s identified phosphate resources total about 300 billion tons, representing 90 million tons of rare earth elements (REE), assuming an average REE content of 300 ppm Under a project funded by the Critical Materials Institute (CMI), the Florida Industrial and Phosphate Research Institute (FIPR Institute) conducted detailed chemical and mineralogical characterization of REE in different phosphate mining and processing streams. The research project include three major parts. Part I covers chemical analysis and some basic properties of different samples. Part II is a detailed process mineralogy study of the amine flotation tails. The third part focuses on isolation and characterization of REE mineral particles in three samples using two advanced techniques, dual energy (DE) rapid scan radiography and high resolution X-ray microtomography (HRXMT). Five samples were collected from a central Florida phosphate operation, including amine flotation tails, waste clay, phosphate rock, phosphoric acid, wet phosphogypsum (PG), and phosphoric acid sludge. These samples were analyzed for rare earth elements, uranium, thorium, routine chemical compositions, and radioactivity. Results show total REE of 70-500 ppm in the samples with uranium ranging from 25-120 ppm. Radium-226 analyzed about 20 pCi/g in phosphogypsum, 28 in phosphate rock, and 0.2 in phosphoric acid, and the corresponding uranium-238 numbers are 2.8, 20 and 36 pCi/g. Simple sizing and chemical analysis of phosphogypsum revealed an extremely encouraging piece of information on REE in PG. About 65% of the REE in PG is concentrated in the minus 500 mesh (approximately 30 microns) fraction that represents less than 10% of the total PG mass. Another fact is that the finest fraction also contains most of the thorium but little uranium. A detailed process mineralogy study was conducted on the amine flotation tails sample using a Mineral Liberation Analyzer, the most advanced instrument for this type of study. Two major rare earth minerals were detected in the amine tails including monazite and xenotime. The monazite monomers average 1.27% CaO, 13.73% La2O3, 29.28% Ce2O3, 12.26% Nd2O3, 0.63% UO2, 6.2% ThO2, 3.55% Pr2O3, 0.46% Al2O3, 1.69% SiO2, and 30.92% P2O5. Xenotime is composed of the following chemicals: 46.44% Y2O3, 2.29% Gd2O3, 5.24% Dy2O3, 3.93% Yb2O3, 0.31% Nd2O3, 4.61% Er2O3, 0.66% Sm2O3, 1.06% UO2, 0.19% CaO, and 35.26 P2O5. Other major minerals in the amine tails include quartz, fluoapatite, feldspar, rutile, pseudorutile and zircon. In Part III, dual energy (DE) rapid scan radiography was used to first identify potential RE particles, followed by a more detailed quantified liberation analysis by high resolution X-ray microtomography (HRXMT). Three sample streams, Shaking Table Concentrate, Acid Plant Feed, and Phosphogypsm, were separated into three size classes: \u3e106 μm, 75-106 μm, and 53-75 μm. DE radiographs were taken at two energy levels and the ratio calculated. The images were thresholded to show only potential rare earth particles and then those particles were removed to prepare HRXMT samples. The samples were digitally reconstructed and the concentration of rare earth particles found using digital processing software. Based on the degree of liberation, the best particle size to find fully liberated monazite particles is 75-106 μm, although other sizes can reasonably be considered for Acid Plant Feed and Phosphogypsm. Based on chemical analyses and minerals characterization, the following conclusions may be made about the occurrence and fate of REE in phosphate mining and processing: 1) REE in the flotation tails exist primarily in monazite with some in xenotime and heavy minerals such as zircon; 2) In the phosphoric acid manufacturing process over 70% of the REE in phosphate rock is dissolved, but a majority (about 70%) of which is either re-precipitated with PG or get absorbed onto PG; 3) the REE in phosphoric acid is mostly precipitated as the acid is concentrated from about 30% P2O5 to 54%; 4) REE in the waste clay occur in two major forms, xenotime and calcium substitution in phosphate crystals

Status of Safeguards and Separations Model Development at Plant and Molecular Levels

A primary goal of the Safeguards and Separations IPSC effort is the development of process modeling tools that allow dynamic simulations of separations plant operations under various configurations and conditions, and integration of relevant safeguards analyses. A requirement of the effort is to develop codes on modern, expandable architectures, with flexibility to explore and evaluate a wide range of process options. During FY09, efforts at ORNL have been focused on two priority tasks toward achieving the IPSC goal: (1) a top-down exploration of architecture - Subtask 1: Explore framework for code development and integration for plant-level simulation; and (2) a bottom-up fundamental modeling effort - Subtask 2: Development of molecular-level agent design code. Subtask 1 is important because definition and development of architecture is a key issue for the overall effort, as selection of an overall approach and code/data requirements is a necessary first step in the organization, design and development of separations and safeguards codes that will be incorporated. The agent design effort of Subtask 2 is a molecular-level modeling effort that has a direct impact on a near-term issue of the Separations and Waste Forms Campaign. A current focus of experimental efforts is the development of robust agents and processes for separation of Am/Cm. Development of enhanced agent-design codes will greatly accelerate discovery and experimental testing

Requirements for a Dynamic Solvent Extraction Module to Support Development of Advanced Technologies for the Recycle of Used Nuclear Fuel

The Department of Energy's Nuclear Energy Advanced Modeling and Simulation (NEAMS) Program has been established to create and deploy next generation, verified and validated nuclear energy modeling and simulation capabilities for the design, implementation, and operation of future nuclear energy systems to improve the U.S. energy security. As part of the NEAMS program, Integrated Performance and Safety Codes (IPSC's) are being produced to significantly advance the status of modeling and simulation of energy systems beyond what is currently available to the extent that the new codes be readily functional in the short term and extensible in the longer term. The four IPSC areas include Safeguards and Separations, Reactors, Fuels, and Waste Forms. As part of the Safeguards and Separations (SafeSeps) IPSC effort, interoperable process models are being developed that enable dynamic simulation of an advanced separations plant. A SafeSepss IPSC 'toolkit' is in development to enable the integration of separation process modules and safeguards tools into the design process by providing an environment to compose, verify and validate a simulation application to be used for analysis of various plant configurations and operating conditions. The modules of this toolkit will be implemented on a modern, expandable architecture with the flexibility to explore and evaluate a wide range of process options while preserving their stand-alone usability. Modules implemented at the plant-level will initially incorporate relatively simple representations for each process through a reduced modeling approach. Final versions will incorporate the capability to bridge to subscale models to provide required fidelity in chemical and physical processes. A dynamic solvent extraction model and its module implementation are needed to support the development of this integrated plant model. As a stand-alone application, it will also support solvent development of extraction flowsheets and integrated safeguards approaches within the Fuel Cycle Research and Development (FCR&D) Program. The purpose of this document is to identify the requirements for this dynamic solvent extraction model to guide process modelers and code developers to produce a computational module that meets anticipated future needs

Requirements for a Dynamic Solvent Extraction Module to Support Development of Advanced Technologies for the Recycle of Used Nuclear Fuel

The Department of Energy's Nuclear Energy Advanced Modeling and Simulation (NEAMS) Program has been established to create and deploy next generation, verified and validated nuclear energy modeling and simulation capabilities for the design, implementation, and operation of future nuclear energy systems to improve the U.S. energy security. As part of the NEAMS program, Integrated Performance and Safety Codes (IPSC's) are being produced to significantly advance the status of modeling and simulation of energy systems beyond what is currently available to the extent that the new codes be readily functional in the short term and extensible in the longer term. The four IPSC areas include Safeguards and Separations, Reactors, Fuels, and Waste Forms. As part of the Safeguards and Separations (SafeSeps) IPSC effort, interoperable process models are being developed that enable dynamic simulation of an advanced separations plant. A SafeSepss IPSC 'toolkit' is in development to enable the integration of separation process modules and safeguards tools into the design process by providing an environment to compose, verify and validate a simulation application to be used for analysis of various plant configurations and operating conditions. The modules of this toolkit will be implemented on a modern, expandable architecture with the flexibility to explore and evaluate a wide range of process options while preserving their stand-alone usability. Modules implemented at the plant-level will initially incorporate relatively simple representations for each process through a reduced modeling approach. Final versions will incorporate the capability to bridge to subscale models to provide required fidelity in chemical and physical processes. A dynamic solvent extraction model and its module implementation are needed to support the development of this integrated plant model. As a stand-alone application, it will also support solvent development of extraction flowsheets and integrated safeguards approaches within the Fuel Cycle Research and Development (FCR&D) Program. The purpose of this document is to identify the requirements for this dynamic solvent extraction model to guide process modelers and code developers to produce a computational module that meets anticipated future needs

Mobile Communication 2012 : Experiències i recerques sobre comunicació mòbil

La comunicació mòbil és un dels temes de més actualitat en diferents fòrums, des de diferents perspectives. Espanya juga un paper important per les dinàmiques i l’evolució del seu mercat. En aquest sentit, el nostre país ofereix un interès específic per l'amplitud del seu parc de dispositius 3G (el segon d'Europa, després d'Itàlia) i per la intensitat del desenvolupament de xarxes socials mòbils, a més de per la creixent implicació d'empreses en la producció i distribució de continguts mòbils. Com va passar amb Internet, es tracta d’un procés d'innovació pel qual els formats de contingut, les pràctiques de consum i els models de negoci característics de la televisió i la xarxa, per exemple, s'adapten, primer, al nou mitjà, per a després desenvolupar formes i models específics que aprofiten les potencialitats de personalització, geolocalització i conectivitat ubiqua

Discovery and Development of Small-Molecule Inhibitors of Glycogen Synthase

The overaccumulation of glycogen appears as a hallmark in various glycogen storage diseases (GSDs), including Pompe, Cori, Andersen, and Lafora disease. Accumulating evidence suggests that suppression of glycogen accumulation represents a potential therapeutic approach for treating these GSDs. Using a fluorescence polarization assay designed to screen for inhibitors of the key glycogen synthetic enzyme, glycogen synthase (GS), we identified a substituted imidazole, (rac)-2-methoxy-4-(1-(2-(1-methylpyrrolidin-2-yl)ethyl)-4-phenyl-1H-imidazol-5-yl)phenol (H23), as a first-in-class inhibitor for yeast GS 2 (yGsy2p). Data from X-ray crystallography at 2.85 Å, as well as kinetic data, revealed that H23 bound within the uridine diphosphate glucose binding pocket of yGsy2p. The high conservation of residues between human and yeast GS in direct contact with H23 informed the development of around 500 H23 analogs. These analogs produced a structure–activity relationship profile that led to the identification of a substituted pyrazole, 4-(4-(4-hydroxyphenyl)-3-(trifluoromethyl)-1H-pyrazol-5-yl)pyrogallol, with a 300-fold improved potency against human GS. These substituted pyrazoles possess a promising scaffold for drug development efforts targeting GS activity in GSDs associated with excess glycogen accumulation

IMPROVED BIOMASS UTILIZATION THROUGH REMOTE FLOW SENSING

The growth of the livestock industry provides a valuable source of affordable, sustainable, and renewable bioenergy, while also requiring the safe disposal of the large quantities of animal wastes (manure) generated at dairy, swine, and poultry farms. If these biomass resources are mishandled and underutilized, major environmental problems will be created, such as surface and ground water contamination, odors, dust, ammonia leaching, and methane emission. Anaerobic digestion of animal wastes, in which microorganisms break down organic materials in the absence of oxygen, is one of the most promising waste treatment technologies. This process produces biogas typically containing {approx}65% methane and {approx}35% carbon dioxide. The production of biogas through anaerobic digestion from animal wastes, landfills, and municipal waste water treatment plants represents a large source of renewable and sustainable bio-fuel. Such bio-fuel can be combusted directly, used in internal combustion engines, converted into methanol, or partially oxidized to produce synthesis gas (a mixture of hydrogen and carbon monoxide) that can be converted to clean liquid fuels and chemicals via Fischer-Tropsch synthesis. Different design and mixing configurations of anaerobic digesters for treating cow manure have been utilized commercially and/or tested on a laboratory scale. These digesters include mechanically mixed, gas recirculation mixed, and slurry recirculation mixed designs, as well as covered lagoon digesters. Mixing is an important parameter for successful performance of anaerobic digesters. It enhances substrate contact with the microbial community; improves pH, temperature and substrate/microorganism uniformity; prevents stratification and scum accumulation; facilitates the removal of biogas from the digester; reduces or eliminates the formation of inactive zones (dead zones); prevents settling of biomass and inert solids; and aids in particle size reduction. Unfortunately, information and findings in the literature on the effect of mixing on anaerobic digestion are contradictory. One reason is the lack of measurement techniques for opaque systems such as digesters. Better understanding of the mixing and hydrodynamics of digesters will result in appropriate design, configuration selection, scale-up, and performance, which will ultimately enable avoiding digester failures. Accordingly, this project sought to advance the fundamental knowledge and understanding of the design, scale up, operation, and performance of cow manure anaerobic digesters with high solids loading. The project systematically studied parameters affecting cow manure anaerobic digestion performance, in different configurations and sizes by implementing computer automated radioactive particle tracking (CARPT), computed tomography (CT), and computational fluid dynamics (CFD), and by developing novel multiple-particle CARPT (MP-CARPT) and dual source CT (DSCT) techniques. The accomplishments of the project were achieved in a collaborative effort among Washington University, the Oak Ridge National Laboratory, and the Iowa Energy Center teams. The following investigations and achievements were accomplished: Systematic studies of anaerobic digesters performance and kinetics using various configurations, modes of mixing, and scales (laboratory, pilot plant, and commercial sizes) were conducted and are discussed in Chapter 2. It was found that mixing significantly affected the performance of the pilot plant scale digester ({approx}97 liter). The detailed mixing and hydrodynamics were investigated using computer automated radioactive particle tracking (CARPT) techniques, and are discussed in Chapter 3. A novel multiple particle tracking technique (MP-CARPT) technique that can track simultaneously up to 8 particles was developed, tested, validated, and implemented. Phase distribution was investigated using gamma ray computer tomography (CT) techniques, which are discussed in Chapter 4. A novel dual source CT (DSCT) technique was developed to measure the phase distribution of dynamic three phase system such as digesters with high solids loading and other types of gas-liquid-solid fluidization systems. Evaluation and validation of the computational fluid dynamics (CFD) models and closures were conducted to model and simulate the hydrodynamics and mixing intensity of the anaerobic digesters (Chapter 5). It is strongly recommended that additional studies be conducted, both on hydrodynamics and performance, in large scale digesters. The studies should use advanced non-invasive measurement techniques, including the developed novel measurement techniques, to further understand their design, scale-up, performance, and operation to avoid any digester failure. The final goal is a system ready to be used by farmers on site for bioenergy production and for animal/farm waste treatment