
	Where results make sense

Topic: Pyrochlore

In the News (Thu 24 Dec 09)

Northern Trust

Marvin Harrison

Peter Chernin

Gary Locke

Match Play

Penelope Cruz

Mickey Rourke

AR Rahman

Danny Boyle

Hugh Jackman

	[No title] (Site not responding. Last check: 2007-09-07)
		Aegirine, albite, apatite grp., barkevikite, biotite, calcite, calzirtite, cancrinite, chromite, clinohumite, clinopyroxene, diopside, dolomite, dysanalyite, feldspar grp., fluorite, forsterite, magnetite, melilite, natrolite, nepheline, olivine, perovskite, phlogopite, pyrochlore, pyrrhotite, spinel, titanite, zeolite grp.
		Aegirine, albite, amphibole grp., ankerite, apatite grp., biotite, calcite, chalcopyrite, columbite, dolomite, feldspar grp., ilmenite, magnesioriebeckite, magnetite, microcline, pyrite, pyrochlore, pyrrhotite, quartz, titanite.
		Aegirine, aeschynite, albite, ankerite, apatite grp., arfvedsonite, baddeleyite, barite, bastnaesite, biotite, burbankite, calcite, calzirtite, cancrinite, carbocernaite, carbonate-apatite, chlorite grp., columbite, diopside, dolomite, eckermannite, fassaite, feldspar grp., fersmanite, fluorite, forsterite, hydromica grp., ilmenite, lueshite, magnesioarfvedsonite, magnesioriebeckite, magnetite, nepheline, parisite, perovskite, phlogopite, pyrite, pyrochlore, pyrrhotite, quartz, richterite, rutile, strontianite, tetraferriphlogopite, titanite, uranpyrochlore, zircon.
	www.koeln.netsurf.de /~w.steffens/ruse.htm (1816 words)

	[No title] (Site not responding. Last check: 2007-09-07)
		Amphibole grp., apatite grp., augite, biotite, calcite, chalcopyrite, dolomite, magnetite, olivine, phlogopite, pyrite, pyrochlore, pyrrhotite, riebeckite, salite, titanite, zircon.
		Apatite grp., augite, biotite, britholite-(Ce), calcite, diopside, dolomite, hauyne, latrappite, magnetite, melilite, monticellite, nepheline, niocalite, periclase, perovskite, pyrite, pyrochlore, pyroxene grp., pyrrhotite, richterite, wollastonite.
		Ankerite, apatite grp., barite, bastnaesite, cancrinite, dolomite, melanite, monazite, monticellite, nepheline, phlogopite, pyrite, pyrochlore, pyrrhotite, sphalerite, titanite.
	www.koeln.netsurf.de /~w.steffens/can.htm (2311 words)

	PYROCHLORE (Calcium Sodium Niobium Oxide Hydroxide Fluoride)
		Pyrochlore is one of the tantalum/niobium oxides that are generally difficult to distinguish.
		Pyrochlore crystallizes in the isometric symmetry class and forms fine octahedral crystals that are typically and characteristically modified by other isometric forms.
		Pyrochlore is the more impure mineral of the two because it is more often accepting of the inclusion of elements such as tantalum, titanium, iron and uranium as well as the previously mentioned rare earth metals into its structure.
	mineral.galleries.com /minerals/oxides/pyrochlo/pyrochlo.htm (460 words)

	Invited lecture at EM '95 (Stara Lesna, Slovak Republic) (Site not responding. Last check: 2007-09-07)
		In powder and thin film PLZT samples it was found that the size of pyrochlore grains increased and the chemical composition of the pyrochlore phase became enriched in Zr and La with increasing temperature.
		Pyrochlore phase was depleted in Pb but enriched in La and Zr content at higher firing temperature while perovskite phase was slightly depleted in the content of La and Zr.
		An increase of the pyrochlore particle size (from 2 nm to around 10 nm), and a simultaneous enrichment of this phase in La and Zr content and depletion in Pb content with increasing firing temperature, were observed in powder and thin film samples.
	cathy.ijs.si /~goran/slovak95.html (2307 words)

	pyrochlore.html (Site not responding. Last check: 2007-09-07)
		Description: Pyrochlore is a group of rare minerals found in pegmatitic granites, syenites and carbonatites.
		- A pyrochlore group mineral was tentatively identifed at the Koss Pit, a "rotten granite" quarry several miles west of Wausau.(SW sec.
		- A pyrochlore group mineral was identifed at the Red Rock North pit, a "rotten granite" quarry along Spring Brook road west of Wausau.
	www.uwrf.edu /~wc01/pyrochlore.htm (152 words)

	Mixed metal pyrochlores (Site not responding. Last check: 2007-09-07)
		The pyrochlore structure is interesting, because it influences the major properties of ceramics such as electronic conductivity and magnetic behaviour.
		The ratio of oxides to fluorides known to posess the pyrochlore structure is about the same as in the spinel or the perovskite family the two largest families of mixed-oxide structures.
		It is therfore a severe problem to decide, wether the series Ce obey the pyrochlore structure or not at least if one does not apply neutron diffraction or anomalous scattering experiments (which are rather expensive methods).
	www.uni-tuebingen.de /uni/pki/members/schinzer/stru_chem/pyro/pyro.html (846 words)

	Abstract Listing - Text Format (Site not responding. Last check: 2007-09-07)
		The chemical composition of pyrochlore covaries with that of its hostrock, without relation to the texture or paragenetic stage.
		Pyrochlore hosted in magnetite and diopside carbonatite is enriched in Ta and U and depleted in Th.
		Pyrochlore in forsterite, forsterite-magnetite-apatite and diopside-magnetite-apatite carbonatite is enriched in Th and depleted in U. Major element geochemistry indicates that fractional crystallization of calcite carbonatite enriched the magma in Fe, Mn and F and led to formation of ferrocarbonatite in the S-60 zone under low oxygen fugacity.
	gac.esd.mun.ca /gac_2004/search_abs/sub_program.asp?sess=98&form=10&abs_no=399 (379 words)

	Niobium - Raw Materials and Processing
		The third major deposit of pyrochlore being actively mined is the Niobec Mine in Quebec, Canada, owned by Cambior, with reserves of 18,000 tonnes.
		In all three facilities, the pyrochlore mineral is processed by primarily physical processing technology to give a concentrate ranging from 55 to about 60% niobium oxide.
		Those companies that mine pyrochlore convert the niobium oxide units into HSLA ferro-niobium through the aluminothermic reduction process or by reduction in an electric arc furnace.
	www.tanb.org /niobium1.html (688 words)

	feat14
		Most notably, many pyrochlore compounds display spin-glass transitions in the apparent absence of chemical disorder, in direct contradiction to well-established theory.
		However, we have discovered that magnetic anisotropy can have the surprising effect of reversing the roles of ferro- and antiferromagnetic exchange couplings with regard to frustration, such that the ferromagnet is highly frustrated and the antiferromagnet is not.
		In the inset to figure F14.1, we show the ground state of a single tetrahedron from the pyrochlore lattice, with ferromagnetic coupling and anisotropy constraining the spins to point along the <111>-type directions.
	www.isis.rl.ac.uk /ISIS98/feat14.htm (909 words)

	Carbonate-associated Deposits: Magmatic, Replacement and Residual - Mineral Deposit Profiles, B.C. Geological Survey
		Only intrusive carbonatites (in some cases further enriched by weathering) are associated with mineralization in economic concentrations which occur as primary igneous minerals, replacement deposits (intra-intrusive veins or zones of small veins, extra-intrusive fenites or veins) or residual weathering accumulations from either igneous or replacement protores.
		Pyrochlore, apatite and rare earth-bearing minerals are typically the most sought after mineral constituents, however, a wide variety of other minerals including magnetite, fluorite, calcite, bornite, chalcopyrite and vermiculite, occur in economic concentrations in at least one carbonatite complex.
		Pyrochlore is disseminated; apatite can be disseminated to semi-massive; bastnaesite occurs as disseminated to patchy accumulations; fluorite forms as veins and masses; hematite is semi-massive disseminations; and chalcopyrite and bornite are found in veinlets.
	www.em.gov.bc.ca /Mining/Geolsurv/MetallicMinerals/MineralDepositProfiles/profiles/n01.htm (1754 words)

	New materials for nuclear waste storage suggested by Science research
		A material akin to the shiny, brown mineral, pyrochlore, results when the size of the cation pairs differs so much that they can't easily trade places.
		In the past, scientists believed that the materials with the brown pyrochlore structure were promising candidates for use in waste containment, because they would be chemically compatible with the waste constituents.
		Both the pyrochlore- and fluorite-type complex oxides are crystalline materials, meaning they consist of units of atoms that, overall, are regularly spaced.
	www.eurekalert.org /pub_releases/2000-08/AAft-Nmfn-0308100.php (758 words)

	Literature on pyrochlore antiferromagnets
		S.E. Palmer and J.T. Chalker, Quantum disorder in the two-dimensional pyrochlore Heisenberg antiferromagnet,
		Yanagishima and Y. Maeno, Metal-Nonmetal Changeover in the Pyrochlore Iridates,
		Di Matteo, G. Jackeli, N. Perkins, Valence-Bond Crystal, and Lattice Distortions in a Pyrochlore Antiferromagnet with Orbital Degeneracy, cond-mat/0501289.
	www.pha.jhu.edu /~olegt/pyrochlore.html (2390 words)

	Structural study and electrical properties of Zr-doped Nd2Sn2O7 pyrochlore compounds
		Nd$_{2}$Sn$_{2}$O$_{7}$ pyrochlores with the substitution of Zr$^{4+}$ were prepared by conventional ceramic double sintering technique.
		O(3) sublattice, is completely vacant and the structure is a perfect cubic pyrochlore with space group Fd3m (O$^{7}_{h}$).
		From the conductivity measurements, it is observed that the electronic conductivity dominates from room temperature up to about 525 K and for $T > 525$ K, the oxygen ion conduction dominates the charge transport in these compositions.
	www.ias.ac.in /pramana/v63/p189/abs.htm (171 words)

	Niocan Inc.
		The pyrochlore minerals, analyzed by Dr. Louis Bernier of Géoberex Research, has a Nb concentration varying between 31% and 62% by weight, while the size of the grains vary from 0.1mm to 3.5mm.
		The size of the pyrochlore grains, which is visible to the naked eye, is the main reason why recovery exceeded 80% in a pilot mill test.
		On the other hand, Dr. Bernier’s mineralogical findings during his analysis of pyrochlore mineral and concentrate samples from S-60 indicate that the radioactive elements uranium and thorium, as well as rare earths metals, are present within the crystalline structure of the pyrochlore.
	www.niocan.com /content.asp?SectionID=9 (1038 words)

	Journel of Materials Research 1998 (Site not responding. Last check: 2007-09-07)
		The formation of pyrochlore and perovskite phases is investigated by high temperature XRD and thermal analysis techniques.
		The pyrochlore phase first appears in x-ray amorphous form, and then gets converted to crystalline state on annealing in air.
		We show that vacuum-annealing of the pyrolyzed amorphous PZT gel suppresses the formation of the crystalline pyrochlore phase.
	www.mrs.org /publications/jmr/jmra/1998/aug/020.html (97 words)

	TSX Venture Exchange Trading Symbol - CCE - Mineral Processing and Metallurgical Testing Commences - Mon Oct 31, 2005 (Site not responding. Last check: 2007-09-07)
		At the Fir Carbonatite, the dominant tantalum-bearing phase is ferrocolumbite with lesser pyrochlore in a ratio of approximately 20 : 1 (columbite : pyrochlore) (Mariano, 1982).
		Pyrochlores have been mined and processed for their niobium content from several carbonatites worldwide, including: Araxa (M.G., Brazil), Catalao I and II (Goias, Brazil), Fen (Norway), Luesche (DRC, Kivu Province), Niobec (Quebec, Canada), and Oka (Quebec, Canada).
		Pyrochlores that are treated by alumina-fusion, produce a high-value Ta / Nb product free of deleterious constituents.
	www.commerceresources.com /s/NewsReleases.asp?ReportID=28267 (583 words)

	Jahrbuch-CD der MPG 2003 - Mixed valence on a pyrochlore l
		Above 40 K, the magnetic susceptibility of the heavy Fermion spinel LiV2O4 has many features in common with those of geometrically frustrated magnetic insulators, while its room temperature resistivity comfortably exceeds the Mott-Regel limit.
		This suggests that local magnetic moments, and the underlying geometry of the pyrochlore lattice, play an important role in determining its magnetic properties.
		We extend a recently introduced tetragonal mean field theory for insulating pyrochlore antiferromagnets to the case where individual tetrahedra contain spins of different lengths, and use this as a starting point to discuss three different scenarios for magnetic and electronic transitions in LiV2O4.
	www.mpg.de /forschungsergebnisse/wissVeroeffentlichungen/archivListenJahrbuch/2002/07/publZIM269.html (127 words)

	Interfacial and Processing Sciences - 9. Analysis and Measurement (Site not responding. Last check: 2007-09-07)
		, with the pyrochlore structure were prepared by a sol-gel route using an aqueous mix of titanium iso-propoxide and the appropriate rare-earth nitrate.
		pyrochlore samples leached at pH 2 for up to 23 days.
		pyrochlores when compared to their crystalline counterparts, although it does not explain the failure to see any effect of amorphization in the Y leach rates.
	www.emsl.pnl.gov /docs/ice/annual_report1999/1615b-9b.html (1116 words)

	Laboratory researchers demonstrate new radiation tolerant materials; implications for waste storage are positive
		Recent research has centered on a class of materials that are part of a larger group of ceramics called complex oxides.
		Pyrochlore is a brownish-fl mineral oxide found in granitic rocks and pegmatites, coarse-grained igneous rocks.
		The researchers tested several combinations and discovered that radiation resistance increases when relatively large metallic ions such as zirconium are included in the compound's atomic structure.
	www.lanl.gov /worldview/news/releases/archive/00-108.shtml (547 words)

	Metall-InfoCenter.de
		If bulk or thin-film ceramics consisting of more than one component are subjected to a high temperature during processing or use, interfacial solid— solid reactions occur between the components.
		To understand this type of reactions, the atomic structure of various reactive oxide/pyrochlore and oxide/spinel model interfaces is studied by high-resolution transmission electron microscopy.
		Kinetics of the pyrochlore-and spinel-forming reactions at these interfaces are shown to depend on the atomic structure of the interface, in particular on that of the interfacial dislocations.
	www.metall-infocenter.de /metall/mk_online/overview_mk.asp?task=3&xid=&mix=jhMNTHVQRQ&refid=&nav_id=231817KDbFS80BP (190 words)

	Rick Ubic College Abstracts (Site not responding. Last check: 2007-09-07)
		Single-phase cubic pyrochlore was obtained for n = 1.5.
		planes between alternating slabs of pyrochlore, similar in appearance to Ruddlesden-Popper phases.
		The occurrence of these layers results in a lowering of the overall symmetry to trigonal, and their presence was found to have a profound effect on the microwave dielectric properties.
	www.qmw.ac.uk /~ugez644/abstracts/02-ur.htm (131 words)

	Synroc
		The specialised form of Synroc which has emerged for this plutonium program is a pyrochlore-rich titanate ceramic with an increased loading of natural uranium and neutron absorbers (Gd, Sm, Hf) needed for nuclear criticality control.
		The baseline wasteform is 95% pyrochlore and 5% rutile (TiO
		Where there is a lot of either sodium or silicon in the wastes, these can form a glass as apart of a durable glass-ceramic composite wasteform.
	www.uic.com.au /nip21.htm (2148 words)

	Influence of strain on the dielectric relaxation of pyrochlore bismuth zinc niobate thin films
		Influence of strain on the dielectric relaxation of pyrochlore bismuth zinc niobate thin films
		It is expected that films under large tensile stress require higher frequencies than bulk BZN to shift the dielectric relaxation to room temperature, which makes these films attractive for low-loss high-frequency applications.
		J W. Lu, D O. Klenov, and Susanne Stemmer, "Influence of strain on the dielectric relaxation of pyrochlore bismuth zinc niobate thin films" (2004).
	repositories.cdlib.org /postprints/267 (254 words)

	Production Capacity (Site not responding. Last check: 2007-09-07)
		- Flotation concentrates pyrochlore in flotation tanks where pyrochlore particles are mixed with chemical reagents and trapped by air bubbles introduced at the bottom of the tank.
		In order to meet the specifications required by industry in general, the pyrochlore concentrate is refined by means of a pyrometallurgical process, developed by
		The economical separation of niobium oxide from pyrochlore ore is one of the most important technological breakthroughs resulting from CBMM research.
	www.cbmm.com.br /english/sources/mine/operat/operat.htm (673 words)

	Commerce Resources Corp. - About Niobium - Mon Oct 31, 2005
		Another pyrochlore mine in Brazil is owned and operated by Mineração Catalão de Goiás Ltda.
		The third major deposit of pyrochlore being actively mined is the Niobec Mine in Quebec, Canada, jointly owned by Cambior and Mazarin, with reserves of 18,000 tonnes.
		These three companies produce about 85% of the world's demand for niobium products, with most of that product being in the form of high-strength, low-alloy ferroniobium containing a nominal 60% niobium oxide content.
	www.commerceresources.com /s/AboutNiobium.asp (579 words)

	Mineral Gallery - The Pyrochlore Group
		The Pyrochlore Group is composed of basically three minerals and members of their respective subgroups.
		The subgroups are named after pyrochlore, betafite and microlite, the three most common and most well known members of the pyrochlore group.
		The Stibiconite Group rarely forms good crystals whereas the Pyrochlore Group is known for fine crystal forms of the isometric system.
	mineral.galleries.com /minerals/oxides/pyrochlo.htm (291 words)

	Oxygen disorder and conductivity in pyrochlore and perovskite (Site not responding. Last check: 2007-09-07)
		Oxygen disorder and conductivity in pyrochlore and perovskite
		Oxygen disorder and conductivity in pyrochlore and perovskite-based compounds.
		powder neutron diffraction and impedance spectroscopy studies of the pyrochlore structured Zr2Nd2O7 and Zr2Gd2O7, brownmillerite structured Ba2In2O5 and perovskite structured Ba(InxZr1-x)O2.5+x/2.
	www.fos.su.se /~pedro/recentpuba10.html (161 words)

	intas 952-0213 (Site not responding. Last check: 2007-09-07)
		Most detailed information for the zirconia (hafnia) and pyrochlore rich compositions will be obtained, such as lattice parameters, boundaries of phase stability, kinetic data on homogenisation of fluorite and pyrochlore solid solutions, and the same during low-temperature synthesis of nanocrystalline powders.
		Dense and fine-grain specimens of prospective ion conductors with fluorite and pyrochlore structures will be obtained and novel data on their conductivity and mechanical properties will be analysed as well.
		In the second part of the Project, an attempt of preparing nanoparticles by non-conventional method of tetragonal, pyrochlore, and cubic zirconia-based powders has been carried out, and the corresponding dense bodies by isothermal and non-isothermal sintering has also been carried out.
	www.intas.be /catalog/952-0213.htm (798 words)

Try your search on: Qwika (all wikis)