Zirconium silicates

The best sealed-in minerals are zircons, zirconium silicate minerals which are formed when melted lava on the flanks of volcanoes solidifies. When the zircons crystallize out, they incorporate radioactive uranium (in particular 238U), which decays in several steps, leading Anally to the lead isotope 208Pb. The rate of decay is very low, as the half-life of uranium-238 is 4.5 x 109 years. Thus, the U-Pb-zircon method for age determination of Precambrian rock is very important. The fossils studied by Schopf were sandwiched between two lava layers (Schopf, 1999). The volcanic layers were dated to 3.458 0.0019 x 109 years and 3.471 0.005 x 109 years the age of the fossil layer (Apex chert) was thus determined to be about 3.465xlO9 years. 

Zirconium silicate crystals, 19 405 Zirconium-silicon alloy, 22 520-521 Zirconium tetrabromide, 26 645 Zirconium tetrachloride, 26 629, 630—631,... 

Zirconium silicate (ZrSiO ) is one form of the mineral whose crystals when polished are known as cubic zircons, which resemble diamond gemstones. 

Synonyms Zirconium dioxide zirconium silicate zirconium tetrachloride... 

German chemist Martin Heinrich Klaproth Durable metal highly resistant to heat its mineral zircon, a compound of zirconium silicate, is a semiprecious gem often substituted for diamonds. 

Zirconium silicate occurs in nature as mineral zircon. Ore is mined from natural deposits and concentrated by various techniques (See Zirconium, Recovery). It is separated from sand by electrostatic and electromagnetic methods. 

Zirconium Carbide Zirconium Hydride Zirconium Hydroxide Zirconium Nitrate Zirconium Oxide Zirconium Silicate Zirconium Sulfate Zirconium Tetrachloride Zirconyl Chloride Chemical Substances Index CAS Registry Number Index... 

Zircon, is a zirconium silicate, ZrSi04, with a tetragonal structure IA jamd)... 

The most important application of praseodymium is the production of very beautiful high ta[tperature resistant lemon-yellow pigments for the ceramic industry. The praseodymium is built into the zirconium silicate lattice and therd y yields full optical splendor. 

The other abrasive agents used are tin oxide, chromic oxide, sand, carbides (silicon carbide and boron carbide), zirconium silicate, zinc oxide, garnet, rouge (fine red powder of iron oxide), kieselgurh, tripoli, magnesium oxide, hydrated silica etc. 

The most efficient matrix for retention of actinides and fission products is the uraninite mineral. However, it has been shown that other matricies such as apatite, clay minerals, zirconium silicates, and oxides (Fe, Mn) may also be important in the retention of fission products and actinides. For example, Pu was stored in apatite (Bros et al. 1996) and chlorite (Bros et al. 1993) in the core of the reactor 10. In the core of the reactors, between uraninite grains, 20-200 (j.m-sized metallic aggregates containing fissiogenic Ru, Rh, and Te associated with As, Pb, and S were found. These aggregates also exist in spent fuels of water-pressured type reactor plants, suggesting their analogy with spent fuels. 

Zirconia. Zircon (zirconium silicate), the most widely occurring zirconium-bearing mineral, is dispersed in various igneous rocks and in zircon sands. The main deposits are in New South Wales, Australia Travancore, India and Florida in the United States. Zircon can be used as such in zircon refractories or as a raw material to produce zirconia. The zircon structure becomes unstable after about 1650°C, depending on its purity, and decomposes into Zr02 and Si02 rather than melting (see Zirconiumand zirconium compounds). 

Zinc oxide (ZnO) is widely used as an active filler in rubber and as a weatherability improver in polyolefins and polyesters. Titanium dioxide (TiOj) is widely used as a white pigment and as a weatherability improver in many polymers. Ground barites (BaS04) yield x-ray-opaque plastics with controlled densities. The addition of finely divided calcined alumina or silicon carbide produces abrasive composites. Zirconia, zirconium silicate, and iron oxide, which have specific gravities greater than 4.5, are used to produce plastics with controlled high densities. 

Nickel—beryllium casting alloys are readily air melted, in electric or induction furnaces. Melt surface protection is supplied by a blanket of argon gas or an alumina-base slag cover. Furnace linings or cmcibles of magnesia are preferred, with zirconium silicate or mullite also adequate. Sand, investment, ceramic, and permanent mold materials are appropriate for these alloys. Beryllium in the composition is an effective deoxidizer and scavenger of sulfur and nitrogen. 

Yeast Cream Stone Slop Starch Solutions Glaze Zirconium Silicate Brewers Yeast Clay Slip... 

In pigments, zirconium silicate serves as the host lattice for various chromophores, such as vanadium, praseodymium, iron, etc. Zirconium silicate crystals are usually formed in situ during pigment preparation by a high temperature reaction of Zr02 and Si02 ... 

Magnesium Zirconium Silicate. MgZrStOs. or MgO ZrO SiO . while solid, nip I760°C. d 80 Ib/ll . insoluble in water and alkalies, slightly soluble in acids. Use Electrical resistor, ceramics, glaze opacilier. 

Zircon pigments are derived from the tetragonal zirconium silicate, ZrSi(>4. Because uf Lite high temperature (up to 1600°C) and chemical stability of zirconium silicate, zircon pigments can be used in the formulations of high temperature (1300- 14O0cC) glazes, Zirconium silicate is also used as an opacifier in porcelain and vitreous enamels. 

Zirconia. Zircon (zirconium silicate), the most widely occurring zirconium-bearing mineral, is dispersed in various igneous rocks and in zircon sands, Zircon can be used as such in zircon refractories or as a raw material to produce zirconia, ZrC>2. 

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