Wulfenite

WULFENITE (from the name of the Austrian mineralogist Franz Xaver von Wulfen * EN: wulfenite, yellow lead ore; DE: Wulfenit; FR: wulfenite; ES: vulfenita; RU: вульфенит) is the mineral of the class of the molybdates, namely, Pb(MoO)4. The wulfenite contains approximately 60% of the Pb element, and 39% of the MoO3 compound; the usual admixtures are the CaO compound (up to 7%), the WO3 compound (up to 28%), and the V2O5 compound (up to 1.3%). The wulfenite crystallizes according to the tetragonal crystal system. The basis of the crystal structure is the isolated [MoO]4 tetrahedra, which are connected by the Pb cations into the chains. The wulfenite is usually represented by the druses or brushes of the well formed tabular or double-pyramidal crystals. The continuous aggregates are rare. The colour is mostly honey-yellow, brown-red to orange. The lustre is strong, greasy to adamantine. The wulfenite is brittle. The hardness is 3. The density is 6800 kilograms per cubic metre.

The wulfenite is the characteristical mineral for the zone of oxidation within the lead deposits. The wulfenite may be encountered in association with the cerussite, anglesite, pyromorphite, vanadinite, and other secondary minerals of lead; the wulfenite is the most widespread mineral of molybdenum after the molybdenite. Within the significant clusters, the wulfenite is the lead ore; less often, the wulfenite is also used as the molybdenum ore. The most known deposits of the wulfenite are within the Algeria, Australia, USA, Yugoslavia, and other countries. The wulfenite is beneficiated using the flotation. The collectors are: the xanthates after the Na2S sulfidation (the pH is 7.5-9.5), the saponified oxidized petrolatum, and the soap stock; the regulator of the environment is the soda. The speed of the sulfidation increases with the increasing of the temperature of the slurry.