Search

Wulfenite is a useful mineral containing both lead and molybdenum. Although the Mo theoretical content of wulfenite is too low to meet the sales requirement, how to pre-concentrate the wulfenite more efficiently and economically becomes increasingly important for subsequent leaching process. Using sodium oleate (NaOL), benzohydroxamic acid (BHA) and sodium dodecyl sulfonate (SDS) as collector, the flotation behavior of wulfenite has been investigated by micro-flotation tests, and the adsorption capacity of the three collectors on wulfenite has been measured and listed as below: NaOL (pH = 9.5) > SDS (pH = 6.5) > BHA (pH = 7.5). According to the frontier orbital theory analysis, when the collector ions act on the {112} surface of wulfenite, the effective mass of NaOL is the lowest, followed by SDS and BHA. Moreover, the molecular dynamics simulation of the three collector ions on wulfenite {112} surface reveals that the two adjacent outermost molybdenum atoms of wulfenite have strong adsorption due to the fracture of the original Mo-O bonds and could easily react with the single-bond oxygen atom outside the polar groups of the three collectors. Comparing the adsorption energy, NaOL has the best adsorption performance to wulfenite {112} surface, during which the O-Mo1 distance and O-Mo2 distance are both below 2.5 Å. By associations of the simulation results with flotation tests, when the feed contains 0.14% Mo, using NaOL as collector, a rough molybdenum concentrate with molybdenum grade of 17.25% and molybdenum recovery of 86.32% has been obtained by conventional flotation tests, which provide theoretical guidance and practical evidence to promote the wulfenite flotation performance. [ABSTRACT FROM AUTHOR]

The article features classical scientist Franz Xaver Freiherr von Wulfen, who discovered and described then-unknown plants, mushrooms, and lichens as well as animals and minerals. Breif overview of Wulfen's personal and educational background, and his focus in three realms of nature such as plants, animals and minerals, is offered. The scientists who have influenced Wulfen's works and his pioneering works in naming several wulfenite specimen are also mentioned.

The article focuses on the qualities and characteristics of wulfenites from Tsumeb, Namibia. Discussion of the history of the first discovery of wulfenites through different mines in the area that lead to the growth of collections in various museums is offered. Description of the different specimens, crystallography, habit and color of wulfenites that were produced in the area is also mentioned.

The article focuses on the history of wulfenite and its subsequent refinement into several categories or varieties of pseudomorphs in Namibia. Brief overview of the meaning and definition of pseudomorph, which has outward form proper to another species of mineral, is offered. The other categories or varieties of pseudomorphs that have entered the literature with recognized terms are also mentioned.

The article focuses on the different wulfenite stamp collections. It mentions philatelic organization American Topical Association (ATA) whose members collect postage stamps of gemstones and minerals from different countries. It also features various postage stamps with unique and distinct pictures of mineral wulfenite.

The article focuses on the characteristics and qualities of wulfenite found in different localities of Mexico. Overview of the different localities of the region which have produced several quantities of great specimens with distinctive beauty and abundance is offered. The history of different mines in various localities in the country are also mentioned.

The article focuses on the different wulfenite localities in New Mexico. Overview of the different mines in the region and the prevalence of wulfenite in the Bennett orebody which have inspired various collectors who were familiar in the area is offered. Information on the geology of wulfenite formation in the area and the history of the collection of the mineral is also mentioned.

The article focuses on the qualities and characteristics of wulfenite found in Arizona. Topics include the approval of the state's legislature and governor for wulfenite as the official state mineral to join copper, the list of best-of-species found in different localities of the state, and the recognized qualities and characteristics of the rock.

The article offers information on minerals that are reported in central Iran such as that of fluorite, andradite, wulfenite, mimetite and vanadinite. Topics discussed include information on Iranian zeolites that are found in northwestern Iran; information on trapezohedral crystals of analcime which were found during construction of a tunnel going through Mount Kahovan, Iran; and information on the Qaragol or Gharah Gol Boron mine located in Zanjan Province, Iran.

The article provides an overview of the mineral collecting localities in Iran and the mineralogical descriptions and observations of some of mineral specimens like wulfenite. Topics include the occurrence of lead-zinc (Zn-Pb) ore deposits in Iranian metallogenic belts, the discovery of Iranian wulfenites at Chah-Kharboze mine, and the wulfenite crystals at Ahmad Abad mine.

The article offers information on the stottite crystals which is discovered in Tsumeb, Namibia in 1957 by miner Friedrich Gramatzki. It says that the stottite crystals become the first naturally occurring germanate around the world and named to honor Charles E. Stott, the general manager of Tsumeb Corp. Ltd. It mentions the importance of analytical verification to correctly identify stottite against siderite and dipyramidal wulfenite.

Variable-temperature (−150°C to 600°C) and high-pressure (up to ∼5 GPa) micro-Raman spectra have been obtained for the mineralwulfenite[lead(II) molybdate(VI), PbMoO4], a main constituent of the artists' pigment,orange molybdate. The spectra were quite similar in both the temperature and the pressure studies, except for broadening and shifting of some peaks. No phase changes were detected, although there is possibly some amorphization beginning at ∼600°C. The photoacoustic IR spectrum in the 1950–450 cm−1region is reported for characterization purposes. The long-term stability of PbMoO4with respect to extreme changes in both temperature and pressure illustrates the importance oforange molybdatein artwork and protective coatings. [ABSTRACT FROM PUBLISHER]

The molybdate-bearing mineral szenicsite, Cu3(MoO4)(OH)4, has been studied by Raman and infrared spectroscopy. A comparison of the Raman spectra is made with those of the closely related molybdate-bearing minerals, wulfenite, powellite, lindgrenite, and iriginite, which show common paragenesis. The Raman spectrum of szenicsite displays an intense, sharp band at 898 cm-1, attributed to the ν1 symmetric stretching vibration of the MoO4 units. The position of this particular band may be compared with the values of 871 cm-1 for wulfenite and scheelite and 879 cm-1 for powellite. Two Raman bands are observed at 827 and 801 cm-1 for szenicsite, which are assigned to the ν3(Eg) vibrational mode of the molybdate anion. The two MO4 ν2 modes are observed at 349 (Bg) and 308 cm-1 (Ag). The Raman band at 408 cm-1 for szenicsite is assigned to the ν4(Eg) band. The Raman spectra are assigned according to a factor group analysis and are related to the structure of the minerals. The various minerals mentioned have characteristically different Raman spectra. [ABSTRACT FROM AUTHOR]

The article focuses on the availability of wearable wulfenite. Brief overview of the different characteristics of wulfenite and the effort of several collectors in completing the information of their collections is offered. The success stories of several people after taking up the challenge of producing facetted and wearable wulfenite are also mentioned.

The article focuses on the history of the value of wulfenite in Tucson, Arizona. Topics include the beginning of how the people's love of wulfenite became an inspiration to the reopening of old mines, mineral stores and dealers in the area, the start of the Tucson Gem and Mineral Show, and the growth of collectors who began collecting the gem.