Zirconium occurrence

Figure Bl.25.9(a) shows the positive SIMS spectrum of a silica-supported zirconium oxide catalyst precursor, freshly prepared by a condensation reaction between zirconium ethoxide and the hydroxyl groups of the support [17]. Note the simultaneous occurrence of single ions (Ff, Si, Zr and molecular ions (SiO, SiOFf, ZrO, ZrOFf, ZrtK. Also, the isotope pattern of zirconium is clearly visible. Isotopes are important in the identification of peaks, because all peak intensity ratios must agree with the natural abundance. In addition to the peaks expected from zirconia on silica mounted on an indium foil, the spectrum in figure Bl. 25.9(a)...

Minerals belonging to the category of insoluble oxide and silicate minerals are many in number. Insoluble oxide minerals include those superficially oxidized and those of oxide type. The former category comprises mainly superficially oxidized sulfide minerals, including metals such as aluminum, tin, manganese, and iron which are won from their oxidic sources. As far as silicate minerals are concerned, there can be a ready reference to several metals such as beryllium, lithium, titanium, zirconium, and niobium which are known for their occurrence as (or are associated with) complex silicates in relatively low-grade deposits. 

There are many advantages of using metal chlorides as interprocess intermediates. One of the most important advantages is that the metal chlorides could be readily purified. In other words, co-occurring metals could be more readily separated from one another as chlorides. This is particularly important when the co-occurring metals have very different technological properties and the presence of one in another in the final product is detrimental to the intended commercial application. A famous example of such co-occurrence is that of zirconium and hafnium in the mineral zircon. Not more than 100 ppm hafnium should be present in the zirconium intended for use in the nuclear reactor core. The hafnium content of zircon is about 2.5%. 

They include the hydrolysis to form the (i-dioxo dimer 49, and the products derived from the formal insertion of nitriles, ketones, and Bu NC into the Zr-C ct bonds. In the case of hydrolysis, butenes have been identified. The occurrence of the zirconyl ( Zr=0 ) group in a monomeric zirconium compound remains... 

Synonyms zircon hyacinth zirconium orthosilicate Occurrence and Uses... 

There are only a few minerals where thorium occurs as a significant constituent. The commercially important ore is the golden-brown, lanthanide phosphate, monazite [13064-1 -8/, LnPO where Ln = Ce, La, or Nd, in which thorium is generally present in a 1—15% elemental composition (7,8). Monazite is widely distributed around the world. Some deposits are quite large. Beach sands from Australia and India contain monazite from which concentrates of lanthanides, titanium, zirconium, and thorium are produced (7). The Travancore deposits in India are the most famous, and have been perhaps one of the most significant sources of commercial thorium. Additional information on the occurrence of thorium in minerals can be found in the literature (7). A review of the mineralogy of thorium is also available (9). 

Occurrence and History.—The name ruthenium is due to Osann,1 who obtained what he believed to be the oxide of a new metal from the Ural platinum ores. This oxide was subsequently investigated by Claus,8 who found that, although it contained a high proportion of the oxides of silicon, zirconium, titanium, and iron, it nevertheless possessed a small quantity of a new oxide for which he retained the name used by Osann. 

Ca) (iii) the nuclear statistical equilibrium peak at the position of Fe and (iv) the abundance peaks in the region past iron at the neutron closed shell positions (zirconium, barium, and lead), confirming the occurrence of processes of neutron-capture synthesis. The solar system abundance patterns associated specifically with the slow (s-process) and fast (r-process) processes of neutron capture synthesis are shown in Figure 2. 

Addition of carbon monoxide and water to an alkene, i.e. hydrocarboxylation, is catalyzed by a variety of transition metal complexes, including [Ni(CO)4], [Co2(CO)s] and [HaPtClg]. Unfortunately this reaction usually leads to mixtures of products due to both metal-catalyzed alkene isomerization and the occurrence of Irath Markownikov and anti-Markownikov addition of the metal hydride intermediate to the alkene. The commercially available zirconium hydride [(C5Hs)2Zr(H)Cl] can be used as a stoichiometric reagent for conversion of alkenes to carboxylic acids under mild conditions (equation 23). In this case the reaction with linear alkenes gives exclusively terminal alkyl complexes even if the alkene double bond is internal. Insertion of CO followed by oxidative hydrolysis then leads to linear carboxylic acids in very good yield. 

There are a number of ways of obtaining U-Pb ages on zircons, but in the last two decades the use of the ion microprobe has become the method of choice. Zircon (zirconium silicate, ZrSi04) is a common mineral in granitic rocks, often abundant as a detrital mineral in clastic sediments and a rare accessory mineral in mafic rocks and some metamorphic rocks. The frequent occurrence of the mineral zircon, and its resilience to later thermal events that would reset other isotopic systems are the reasons for its frequent use in studies of the early Earth. 

Occurrence.4 — The chief zirconium minerals are zircon, an orthiindicate, ZrSiO, tuul baddoloyite, Zr()2, with traces of... 

Successful processes for separating hafnium from zirconium take advantage of rather rare occurrences of substantial differences in solubilities of corresponding hafnium and zirconium compounds in water, organic solvents, fused salts, or liquid metals. 

Chapters S, 6, and 7 take up uranium, thorium, and zirconium in that order. Each chapter discusses the physical and chemical properties of the element and its compounds, its natural occurrence, and the processes used to extract the element from its ores, purify it, and convert it to the forms most useful in nuclear technology. 

Birch WD, Bring A, Bevan DJM, Khaiisun (1994) Wycheproofite a new hydrated sodium aluminum zirconium phosphate frmom Wycheproof, Victoria, Australia, and a new occurrence of kosnarite. Mineral Mag 58 635-639... 

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