mineral formations containing vanadium in amounts sufficient to make extraction of the element by modern methods economically feasible. The most important vanadium-ore minerals are vanadinite (19 percent V2O5), descloizite (22 percent), cuprodescloizite (17-22 percent), carnotite (20 percent), roscoelite (21-29 percent), and patronite (17-29 percent). Vanadium is present as an admixture in the following ore minerals: titanomagnetite (up to 8.8 percent V2O5), magnomagnetite (1.6 percent), magnetite (0.6 percent), rutile (1 percent), and ilmenite (0.4 percent).
Vanadium-ore deposits may be endogenic or exogenic. Endogenic deposits are found in areas of ultrabasic, basic, and alkaline rocks; they are formed by magmatic, contact-metasomatic, and hydrothermal processes. Endogenic deposits may be magmatic (titanomagnetite, magnetite-ilmenite, and ilmenite-hematite in pyroxenites, hornblendes, olivinites, gabbro, norites, anorthosites, and gabbro-diabases), contact-metasomatic (magnetite in scarned rock), or hydrothermal-magnomagnetite (in regions of widespread traps). Endogenic ore deposits are characterized by a low vanadium content (0.1-1 percent V2O5), but the reserves are very large. The best-known deposits are in the USSR (Gusinaia Gora), the Republic of South Africa (Magnet), the USA (Tahawus), Canada (Lac Tio), Sweden (Taberg), and Finland (Otanmäki).
Exogenic deposits of vanadium ores include descloizite, cuprodescloizite, and vanadinite deposits in oxidation zones of lead-zinc and copper ores (containing 2-10 percent V2O5); carnotite and roscoelite deposits among the mottled rocks of the Colorado Plateau type (1-5 percent); vanadium-bearing phosphorites (0.1-1 percent) and petroleum (5-58 percent in the ash); patronite deposits in asphaltites (up to 50 percent in the ash); and titanomagnetite alluvial deposits, primarily offshore marine (approximately 0.3 percent). Large exogenic deposits are known to exist in the USA (the Colorado Plateau), Namibia (Berg Aukas), and Zambia (Broken Hill).
All types of vanadium ore are complex and contain iron, titanium, uranium, lead, zinc, copper, molybdenum, aluminum, and phosphorus, in addition to vanadium. Possible future sources of vanadium include oolitic brown ironstones (iron-phosphorus ores), which are characterized by a low V2O5 content (0.07-0.2 percent) but large reserves; carbonaceous-siliceous shales (0.2-1.5 percent V2O5); bauxites (0.02-0.04 percent); coal and fuel shale ash (0.2 percent); and marine iron-manganese concretions (0.1 percent). In 1968 vanadium production in capitalist countries was 10,000 tons, of which the USA accounted for 5,200 tons and the Republic of South Africa for 2,300 tons.
REFERENCEDenchev, V. I., and P. P. Shilovskii. “Vanadii.” In the collection Metally v osadochnykh tolshchakh [vol. 2]. Moscow, 1965.
L. F. BORISENKO