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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==Storage== | ==Storage== | ||
==Disposal== | ==Disposal== | ||
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 monovalent alkali metal 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) + NaSO4}} | |||
: {{#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]] | ||
Revision as of 19:07, 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 |  0
1
0
|
Uses
Primary
- The γ-anhydrite form (1-5 molar percent water) is the primary component of gypsum plaster
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 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 monovalent alkali metal salts while maintaining low temperatures, large amounts of water, and strong intermixing:
- CaSO4(s) + 2 NaOH(aq){Ca(OH)2(aq) + NaSO4≤ 18°C strong mixing}→
- CaSO4(s) + Na2CO3(aq){CaCO3(aq) + Na2SO4 // may also work with bicarbonate, producing bisulfatecold, strong mixing}→