Minerals of the pyrochlore group as niobium-ore

March 27th, 2012  Posted by jmwarnsloh

In comparison to other commodities, e.g. gold, niobium-ores are related to a small number of igneous rocks, in particular carbonatites and genetically-related silicate-carbonate rocks.
Within these rocks niobium is segregated principally in oxide minerals such as the pyrochlore-microlite solid solution series (Ca,Na)2(Nb,Ta)2O6(O,OH,F) and niobian perovskite (Ca,Na)(Ti,Nb)O3. At least four other Nb minerals can occur in sufficient quantities to dominate or affect the niobium content of a carbonatite. They include ferrocolumbite FeNb2O6, fersmite (Ca,REE,Na)(Nb,Ta,Ti)2(O,OH,F)6, niocalite Ca4NbSi2O10(O,F), and wöhlerite NaCa2(Zr,Nb)Si2O8(O,OH,F). Pyrochlore is the dominant niobium host and the only mineral

World-wide Niobium and Tantalum Availability

March 26th, 2012  Posted by jmwarnsloh

Niobium is a shiny, white, soft, and ductile metal with superconductive properties. Niobium products are used in a wide variety of applications. The largest end market for HSLA steel is for large diameter steel pipelines for the transmission of natural gas and oil. Price increases in oil and natural gas during the last years have created a new interest in exploration for, and

The effect of hydrothermal alteration and metamictisation on the U-Th-Pb- distribution and U-Pb-systematics of pyrochlore of the Sokli carbonatite complex, N-Finland

March 26th, 2012  Posted by jmwarnsloh

Pyrochlore is a common accessory mineral in granite pegmatites, nepheline syenites and carbonatites. Its ability to accomodate many different elements lead to a wide range of pyrochlore varieties. This is obvious for the U- and Th- contents. The Sokli carbonatite complex is part of the Kola alkaline province (KAP) in the northern Baltic Shield. The complex is situated in the area of Savukoski, Finish Lapland, close to the border to Russia. The emplacement age of 360 – 370 Ma falls in

Pyrochlore Composition As Indicator For The Carbonatite Evolution Stages At Sokli?

March 26th, 2012  Posted by jmwarnsloh

Pyrochlore is a common accessory mineral in granite pegmatites, nepheline syenites and carbonatites. The general chemical formular is A2-mB2X6-wY1-n • pH2O where A includes Na, Ca, U, Th , Pb, REE, Ba and Sr; B includes Nb, Ta, Ti, Zr and Fe; X = O and OH; Y = O, OH and F. The ability to accomodate many different elements leads to a wide range of pyrochlore varieties.
In Sokli (Finland) pyrochlore composition

U-Th-Pb- elemental and isotopic distribution of pyrochlore minerals from the Sokli carbonatite complex, N-Finland

March 26th, 2012  Posted by jmwarnsloh

Pyrochlore, ideally (Ca,Na)2(Nb5O6)(OH,F), is a relatively common accessory mineral in many rock-types including carbonatites. In the Sokli carbonatite, N. Finland, pyrochlore concentrates to economically important amounts, where it forms the ore mineral of niobium.