Calcium sulfate: Difference between revisions
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JeffEvarts (talk | contribs) (Created page with "{{Compound|chemf=CaSO4 |mm=136.14|density=2.96|mp=1460|sol_aq=2.1 |group=salts |stp_p=solid|stp_q=white |nfpa_h=1}} ==Uses== ===Primary=== * The γ-anhydrite form (1-5 mo...") |
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===Primary=== | ===Primary=== | ||
* The γ-anhydrite form (1-5 molar percent water) is the primary component of [[plaster#Gypsum Plaster|gypsum plaster]] | * The γ-anhydrite form (1-5 molar percent water) is the primary component of [[plaster#Gypsum Plaster|gypsum plaster]] | ||
===Secondary=== | |||
* Carbon sequestration and source of sulfate by converstion to [[calcium carbonate]] | |||
==Natural occurrence== | ==Natural occurrence== | ||
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==Storage== | ==Storage== | ||
==Disposal== | ==Disposal== | ||
Calcium sulfate in any degree of hydration is a naturally occurring minearl and may be disposed of directly into the environment. | |||
Calcium sulfate is not a terminal state for sulfate or calcium. Calcium sulfate may be converted to [[sodium sulfate]] and either [[calcium hydroxide]] or [[calcium carbonate]] by combining it with sodium salts while maintaining ''low temperatures'', large amounts of water, and strong intermixing: | |||
: {{#Chem: CaSO4(s) + 2NaOH(aq) { = ≤ 18°C strong mixing } Ca(OH)2(aq) + Na2SO4}}<ref>{{cite patent|title=Removal of calcium sulfate deposits | |||
|3170815}}</ref> | |||
: {{#Chem: CaSO4(s) + Na2CO3(aq) { = cold, strong mixing } CaCO3(aq) + Na2SO4 // may also work with bicarbonate, producing bisulfate}} | |||
==References== | ==References== | ||
<references/> | <references/> | ||
==See Also== | ==See Also== | ||
* [[Gypsum]] | * [[Gypsum]] |
Latest revision as of 19:11, 16 April 2020
Chemical formula | CaSO4 |
---|---|
OTP appearance | white solid |
Molar Mass(g/mol) | 136.14 |
Density(g/cc) | 2.96 |
Melting Point(°C) | 1460 |
Solubility in water(g/L) | 2.1 |
NFPA 704 |
Uses
Primary
- The γ-anhydrite form (1-5 molar percent water) is the primary component of gypsum plaster
Secondary
- Carbon sequestration and source of sulfate by converstion to calcium carbonate
Natural occurrence
- -dihydrate occurs naturally as gypsum
Hazards
Production
Extraction
from gypsum
- Heat gypsum to over 180°C producing anhydrite
Synthesis
as a byproduct
- During the production of phosphoric acid:
- Ca3(PO4)2 + 3 H2SO4 → 2 H3PO4 + 3 CaSO4
from chalk
- Combine sulfuric acid and calcium carbonate
- CaCO3 + H2SO4 → CaSO4 + H2O + CO2
Testing
Storage
Disposal
Calcium sulfate in any degree of hydration is a naturally occurring minearl and may be disposed of directly into the environment.
Calcium sulfate is not a terminal state for sulfate or calcium. Calcium sulfate may be converted to sodium sulfate and either calcium hydroxide or calcium carbonate by combining it with sodium salts while maintaining low temperatures, large amounts of water, and strong intermixing:
- CaSO4(s) + 2 NaOH(aq){Ca(OH)2(aq) + Na2SO4[1]≤ 18°C strong mixing}→
- CaSO4(s) + Na2CO3(aq){CaCO3(aq) + Na2SO4 // may also work with bicarbonate, producing bisulfatecold, strong mixing}→
References
- ↑ US patent 3170815 "Removal of calcium sulfate deposits"
Link courtesy Google