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 (more…)
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 (more…)
The coal mining waste dump Anna I of the Anna black coal underground mine in Alsdorf (Germany) – in operation between 1854 and 1983 – is characterized by internal combustion. Volatile products of this process are emitted though vent-like holes and fractures on the top of the dump. Surface temperatures are heterogeneous within a dm-scale and partly exceed 210 degrees centigrade. The pH of condensed vapour (more…)
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 (more…)
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. (more…)