Zirconium(IV) silicate

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Zirconium(IV) silicate
Identifiers
CAS number 10101-52-7 YesY
PubChem 61775
ChemSpider 55663 N
EC number 233-252-7
MeSH Zircon
Jmol-3D images Image 1
Properties
Molecular formula O4SiZr
Molar mass 183.31 g mol−1
Appearance Colourless crystals
Density 4.56 g cm-3
Melting point 2,550 °C (4,620 °F; 2,820 K) (decomposes)
Hazards
MSDS MSDS
EU Index Not listed
NFPA 704
Flammability code 0: Will not burn. E.g., water Health code 1: Exposure would cause irritation but only minor residual injury. E.g., turpentine Reactivity code 1: Normally stable, but can become unstable at elevated temperatures and pressures. E.g., calcium Special hazards (white): no codeNFPA 704 four-colored diamond
Flash point Non-flammable
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 N (verify) (what is: YesY/N?)
Infobox references

Zirconium silicate, also zirconium orthosilicate, (ZrSiO4) is a chemical compound, a silicate of zirconium. It occurs in nature as the zircon, a silicate mineral. Zirconium silicate is also sometimes known as zircon flour.

Zirconium silicate is usually colorless, but impurities induce various colorations. It is insoluble in water, acids, alkali and aqua regia. Hardness is 7.5 on the Mohs scale.[1]

Production[edit]

See also: Chernobylite

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

Also, the compound can be made by fusion of SiO2 and ZrO2 in an arc furnace, or by reacting a zirconium salt with sodium silicate in an aqueous solution.

Uses[edit]

Zirconium silicate is used for manufacturing refractory materials for applications where resistance to corrosion by alkali materials is required. It is also used in production of some ceramics, enamels, and ceramic glazes. In enamels and glazes it serves as an opacifier. It can be also present in some cements. Another use of zirconium silicate is as beads for milling and grinding. Thin films of zirconium silicate and hafnium silicate produced by chemical vapor deposition, most often MOCVD, can be used as a high-k dielectric as a replacement for silicon dioxide in semiconductors.[2]

Zirconium silicates have also been used in medical applications. For example, ZS-9 is a zirconium silicate that was designed specifically to trap potassium ions over other ions throughout the gastrointestinal tract.[3] ZS-9 is being developed for oral administration to treat hyperkalemia (increased serum potassium levels). Currently, the only product approved by the FDA to treat hyperkalemia is sodium polystyrene sulfonate (Kayexalate). However, Kayexalate is an organic ion-exchange resin that nonspecifically entraps cations including potassium, magnesium, and calcium. Kayexalate has also been associated with cases of serious gastrointestinal adverse events and colonic necrosis.[4]

During the process that ultimately resulted in ZS-9, zirconium silicate candidate molecules were optimized to selectively capture potassium cations and to have an optimal balance of counter ions. This was accomplished by screening zirconium silicate compounds to find one that mimicked the action of physiologic potassium channels and to exchange the counter ions present in the drug candidates.

In a randomized, double-blind, placebo-controlled, phase 2 clinical trial in patients with chronic kidney disease and hyperkalemia, ZS-9 three times daily for 2 days reduced potassium levels to a significantly greater extent than did placebo, and ZS-9 was well tolerated.[5] Similar results were observed in a randomized, double-blind, placebo-controlled phase 3 clinical trial with ZS-9 given three times daily for 2 days.[6] ZS-9 given once daily for 12 additional days during an extended treatment phase was able to maintain a significant reduction in serum potassium relative to placebo.[7] ZS-9 was well-tolerated at all doses, with comparable rates of overall adverse events and GI adverse events between the placebo and ZS-9 treated patients.[8]

Toxicity[edit]

Zirconium silicate is an abrasive irritant for skin and eyes. Chronic exposure to dust can cause pulmonary granulomas, skin inflammation, and skin granuloma.[9] However, there are no known adverse effects for normal, incidental ingestion.[10]

References[edit]

  1. ^ P. Patnaik (2002). Handbook of inorganic chemicals. McGraw-Hill Professional. p. 1002. ISBN 0-07-049439-8. 
  2. ^ Lide, David R. (1998). Handbook of Chemistry and Physics (87 ed.). Boca Raton, FL: CRC Press. pp. 4–96. ISBN 0-8493-0594-2. 
  3. ^ http://www.zspharma.com/ZS-9.html
  4. ^ Sterns RH, Rojas M, Bernstein P, Chennupatie S. (2010) Ion-exchange resins for the treatment of hyperkalemia: are they safe and effective. J Am Soc Nephrol 21: 733-735
  5. ^ Ash SA, Singh B, Lavin PT, Stavros F, Rasmussen HS. (2013) Safety and efficacy of ZS-9, a novel selective cation trap, for treatment of hyperkalemia in CKD patients. J Am Soc Nephrol 24: 2B (abstract)
  6. ^ http://www.zspharma.com/downloads/ZS_Pharma_Announces_Positive_Top-Line_Results_of_Phase_3_Trial_of_ZS-9_in_Patients_with_Hyperkalemia.pdf
  7. ^ http://www.zspharma.com/downloads/ZS_Pharma_Announces_Positive_Results_from_the_Extended_Treatment_Phase.pdf
  8. ^ http://www.zspharma.com/downloads/ZS_Pharma_Announces_Positive_Results_from_the_Extended_Treatment_Phase.pdf
  9. ^ "Zirconium silicate MSDS". Retrieved 2009-06-06. [dead link]
  10. ^ http://www.agsco.com/MSDS/Zirconium%20Silicate.pdf