Calcium nitrate

Calcium nitrate
Names
Other names
Kalksalpeter, nitrocalcite, Norwegian saltpeter, lime nitrate
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.030.289
RTECS number EW2985000
UNII
UN number 1454
Properties
Ca(NO3)2
Molar mass 164.088 g/mol (anhydrous)
236.15 g/mol (tetrahydrate)
Appearance colorless solid
hygroscopic
Density 2.504 g/cm3 (anhydrous)
1.896 g/cm3 (tetrahydrate)
Melting point 561 °C (1,042 °F; 834 K) (anhydrous)
42.7 °C (109 °F; 316 K) (tetrahydrate)
Boiling point decomposes (anhydrous)
132 °C (270 °F; 405 K) (tetrahydrate)
anhydrous:
1212 g/L (20 °C)
2710 g/L (40 °C)
tetrahydrate:
1050 g/L (0 °C)
1290 g/L (20 °C)
3630 g/L (100 °C)
Solubility soluble in ammonia
almost insoluble in nitric acid
Solubility in ethanol 51.4 g/100 g (20 °C)
62.9 g/100 g (40 °C)[1]
Solubility in methanol 134 g/100 g (10 °C)
144 g/100 g (40 °C)
158 g/100 g (60 °C)[1]
Solubility in acetone 16.8 g/kg (20 °C)[1]
Acidity (pKa) 6.0
-45.9·10−6 cm3/mol
Structure
cubic (anhydrous)
monoclinic (tetrahydrate)
Hazards
Safety data sheet ICSC 1037
R-phrases (outdated) R22, R41
NFPA 704
Flash point Non-flammable
Lethal dose or concentration (LD, LC):
302 mg/kg (rat, oral)
Related compounds
Other anions
 Calcium sulfate
Calcium chloride
Other cations
 Magnesium nitrate
Strontium nitrate
Barium nitrate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YesYN ?)
Infobox references

Calcium nitrate, also called Norgessalpeter (Norwegian saltpeter), is the inorganic compound with the formula Ca(NO3)2. This colourless salt absorbs moisture from the air and is commonly found as a tetrahydrate. It is mainly used as a component in fertilizers but has other applications. Nitrocalcite is the name for a mineral which is a hydrated calcium nitrate that forms as an efflorescence where manure contacts concrete or limestone in a dry environment as in stables or caverns. A variety of related salts are known including calcium ammonium nitrate decahydrate and calcium potassium nitrate decahydrate.[2]

Production and reactivity

Norgessalpeter was synthesized at Notodden, Norway in 1905 by the Birkeland–Eyde process. Most of the world's calcium nitrate is now made in Porsgrunn.

It is produced by treating limestone with nitric acid, followed by neutralization with ammonia:

CaCO3 + 2 HNO3 → Ca(NO3)2 + CO2 + H2O

It is also an intermediate product of the Odda Process:

Ca3(PO4)2 + 6 HNO3 + 12 H2O → 2 H3PO4 + 3 Ca(NO3)2 + 12 H2O

It can also be prepared from an aqueous solution of ammonium nitrate, and calcium hydroxide:

2 NH4NO3 + Ca(OH)2 → Ca(NO3)2 + 2 NH4OH

Like related alkaline earth metal nitrates, calcium nitrate decomposes upon heating (starting at 500 °C) to release nitrogen dioxide:[2]

2 Ca(NO3)2 → 2 CaO + 4 NO2 + O2 ΔH = 369 kJ/mol

Applications

Use in agriculture

As of 1978, only 170,000 tons/year were produced for applications in fertilizers.[2] The fertilizer grade (15.5-0-0 + 19% Ca) is popular in the greenhouse and hydroponics trades; it contains ammonium nitrate and water, as the "double salt" 5Ca(NO3)2.NH4NO3·10H2O. This is called calcium ammonium nitrate. Formulations lacking ammonia are also known: Ca(NO3)2·4H2O (11.9-0-0 + 16.9%Ca). A liquid formulation (9-0-0 + 11% Ca) is also offered. An anhydrous, air-stable derivative is the urea complex Ca(NO3)2·4[OC(NH2)2], which has been sold as Cal-Urea.

Calcium nitrate is also used to control certain plant diseases. For example, dilute calcium nitrate (and calcium chloride) sprays are used to control bitter pit and cork spot in apple trees.[3]

Waste water treatment

Calcium nitrate is used in waste water pre-conditioning for odour emission prevention. The waste water pre-conditioning is based on establishing an anoxic biology in the waste water system. In the presence of nitrate, the metabolism for sulfates stops, thus preventing formation of hydrogen sulphide.[4] Additionally easy degradable organic matter is consumed, which otherwise can cause anaerobic conditions downstream as well as odour emissions itself. The concept is also applicable for surplus sludge treatment.[5]

Concrete

Calcium nitrate is used in set accelerating concrete admixtures. This use with concrete and mortar is based on two effects. The calcium ion accelerates formation of calcium hydroxide and thus precipitation and setting. This effect is used also in cold weather concreting agents as well as some combined plasticizers.[6] The nitrate ion leads to formation of iron hydroxide, whose protective layer reduces corrosion of the concrete reinforcement.[7]

Latex coagulant

Calcium nitrate is a very common coagulant in latex production, especially in dipping processes. Dissolved calcium nitrate is a part of the dipping bath solution. The warm former is dipped into the coagulation liquid and a thin film of the dipping liquid remains on the former. When now dipping the former into the latex the calcium nitrate will break up the stabilization of the latex solution and the latex will coagulate on the former.[8][9]

Cold packs

The dissolution of calcium nitrate tetrahydrate is highly endothermic (cooling). For this reason, calcium nitrate tetrahydrate is sometimes used for regenerable cold packs.[2]

Molten salts for heat transfer and storage

Calcium nitrate can be used as a part of molten salt mixtures. Typical are binary mixtures of calcium nitrate and potassium nitrate or ternary mixtures including also sodium nitrate.[10][11][12] Those molten salts can be used to replace thermo oil in concentrated solar power plants for the heat transfer, but mostly those are used in heat storage.

References

  1. 1 2 3 Anatolievich, Kiper Ruslan. "Properties of substance: calcium nitrate". Retrieved 2015-09-09.
  2. 1 2 3 4 Wolfgang Laue, Michael Thiemann, Erich Scheibler, Karl Wilhelm Wiegand "Nitrates and Nitrites" in Ullmann's Encyclopedia of Industrial Chemistry, 2002, Wiley-VCH, Weinheim.doi:10.1002/14356007.a17_265. Article Online Posting Date: June 15, 2000
  3. ↑ "Bitter Pit and Cork Spot". University of Wisconsin-Extension Cooperative Extension. UW-Madison, Dept of Horticulture.
  4. ↑ Bentzen, G; Smith, A; Bennett, D; Webster, N; Reinholt, F; Sletholt, E; Hobson, J (1995). "Controlled dosing of nitrate for prevention of H2S in a sewer network and the effects on the subsequent treatment process". Water Science and Technology. 31 (7): 293. doi:10.1016/0273-1223(95)00346-O.
  5. ↑ Einarsen, A.M.; ÆeesØy, A.; Rasmussen, A. I.; Bungum, S.; Sveberg, M. (2000). "Biological prevention and removal of hydrogen sulphide in sludge at Lillehammer Wastewater Treatment Plant". Water Sci. Technol. 41 (6): 175–187.
  6. ↑ Justines, H. (2010) "Calcium Nitrate as a Multifunctional Concrete Admixture" Concrete Magazine, Vol 44, No. 1, p.34. ISSN 0010-5317
  7. ↑ Al-Amoudi, Omar S.Baghabra; Maslehuddin, Mohammed; Lashari, A.N; Almusallam, Abdullah A (2003). "Effectiveness of corrosion inhibitors in contaminated concrete". Cement and Concrete Composites. 25 (4–5): 439. doi:10.1016/S0958-9465(02)00084-7.
  8. ↑ N. C. Dafader, Y. N. Jolly, M. E. Haque, F. Akhtar & M. U. Ahmad: The Role of Coagulants on the Preparation of Dipped film from Radiation Vulcanized Natural Rubber Latex. Polymer-Plastics Technology and Engineering. Volume 38, Issue 2, 1999, pages 267-274. Online: http://www.tandfonline.com/doi/abs/10.1080/03602559909351576
  9. ↑ http://www.rubbercare.com.my/process.html
  10. ↑ http://www.solarnovus.com/potassium-calcium-nitrate-promising-for-csp-heat-storage_N6044.html
  11. ↑ European Patent Application EP0049761: Use of a ternary mixture of salts as a heat transmitting medium and/or as a heat storage medium. http://www.freepatentsonline.com/EP0049761A1.html
  12. ↑ WIPO Patent Application WO/2014/044652: USE OF A CALCIUM POTASSIUM NITRATE SALT FOR THE MANUFACTURE OF A HEAT TRANSFER FLUID. http://www.freepatentsonline.com/WO2014044652A1.html
Salts and covalent derivatives of the Nitrate ion
HNO3 He
LiNO3 Be(NO3)2 B(NO3)4− C N O FNO3 Ne
NaNO3 Mg(NO3)2 Al(NO3)3 Si P S ClONO2 Ar
KNO3 Ca(NO3)2 Sc(NO3)3 Ti(NO3)4 VO(NO3)3 Cr(NO3)3 Mn(NO3)2 Fe(NO3)3,
Fe(NO3)2		 Co(NO3)2,
Co(NO3)3		 Ni(NO3)2 Cu(NO3)2 Zn(NO3)2 Ga(NO3)3 Ge As Se Br Kr
RbNO3 Sr(NO3)2 Y Zr(NO3)4 Nb Mo Tc Ru Rh Pd(NO3)2 AgNO3 Cd(NO3)2 In Sn Sb(NO3)3 Te I Xe(NO3)2
CsNO3 Ba(NO3)2   Hf Ta W Re Os Ir Pt Au Hg2(NO3)2,
Hg(NO3)2		 Tl(NO3)3,
TlNO3		 Pb(NO3)2 Bi(NO3)3
BiO(NO3)		 Po At Rn
FrNO3 Ra(NO3)2   Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og
↓
La(NO3)3 Ce(NO3)3,
Ce(NO3)4		 Pr Nd Pm Sm Eu Gd(NO3)3 Tb Dy Ho Er Tm Yb Lu
Ac(NO3)3 Th(NO3)4 Pa UO2(NO3)2 Np Pu Am Cm Bk Cf Es Fm Md No Lr
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.