Saturated aqueous solutions in Potash industry. Modeling of properties...
Transcript of Saturated aqueous solutions in Potash industry. Modeling of properties...
Saturated aqueous solutions in Potash
industry. Modeling of properties and composition
Sergei Panasiuk, Ph.D. Chief mineral process specialist
WorleyParsons Canada, Minerals & Metals
Potash – any potassium compound (KCl – most common).
Potash = “pot ashes” old method of making K2CO3 by
leaching of wood ashes, evaporating the resulting solution in
iron pots.
The first U.S patent issued in 1790 and sighed by G.
Washington. “in the making of Pot ash … by new Apparatus
and Process”.
Samuel Hopkins
“…making of Pot ash and Pearl ash by a
new Apparatus and Process”
In 1791, Government of Lower Canada
(Quebec) issued “letter of reward” to
Hopkins for his improved method.
Regarded as the first “patent” issued in
Canada.
Potassium minerals
Mineral Composition K2O, %
Chlorides:
Sylvinite KCl · NaCl mixture 28
Sylvite KCl 63
Carnalite KCl · MgCl2 · H2O 17
Kainite 4KCl · 4MgSO4 · 11H2O 19
Hanksite KCl · 9Na2SO4 · 2Na2CO3 3
Sulphates:
Polyhalite K2SO4 · 2MgSO4 · 2CaSO4 · 2H2O 16
Langeinite K2SO4 · 2MgSO4 23
Leonite K2SO4 · MgSO4 · 4H2O 26
Schoenite K2SO4 · MgSO4 · 6H2O 23
Krugite K2SO4 · MgSO4 · 4CaSO4 · 2H2O 11
Glaserite 3K2SO4 · Na2SO4 43
Syngenite K2SO4 · CaSO4 · H2O 29
Aphthitalite (K,Na)2SO4· 30
Kalinite KAl(SO4)2 · 11H2O 10
Alunite K2Al6(OH)12 · (SO4)4 11
Nitrates:
Niter KNO3 47
Mines (Canada, USA, Russia) - 96%
Evaporating ponds (USA, Jordan, Israel) - 3%
NEW
Block Flow Diagram – Potash Solution Mine
Solubility: - Flotation (salts and amines)
- U/G solution mining
- Brine evaporation
- KCl crystallization
- Brine U/G injection
Density: - U/G solution mining
- Evaporation/crystallization
- Brine U/G injection
Vapor pressure and composition: - Evaporation/crystallization
- Exhaust gas scrubbers
- Dryers
Boiling point elevation: - Evaporation/crystallization
- Dryers
KC l- NaCl - H2O
0
5
10
15
20
25
30
35
0 5 10 15 20 25 30 35 40
Na
Cl,
wei
gh
t %
KCl, weight %
OLI data 0C
25C
50C
75C
100C
150C
NaCl
KCl
NaCl + KCl
Solution mine
NaCl saturated
KCl depleted
KCl -NaCl
NaCl
NaCl
65 °C 55 °C
NaCl saturated
KCl saturated
1500 m depth
No problems?
OLI predicts proper pH for the vapor condensate from evaporators but not for dryers.
1
MgCl2·2H2O = MgOHCl + HCl + H2O t > 135 °C
Problem 2
NaCl saturated
KCl depleted
KCl -NaCl
NaCl
NaCl
65 °C 55 °C
NaCl saturated
KCl saturated
1500 m depth
Conclusions:
• Potash industry requires accurate prediction of solubility in system
K-Na-Mg-Cl-SO4-H2O system
• Predictions of the brine density, boiling point elevation, viscosity,
vapor pressure and compositions are also very important
• METSIM uses polynomial functions to approximate some of the
brine parameters
• OLI is capable to predict all required brine properties in the wide
range of conditions
• OLI and METSIM predictions of the brine properties are very
similar in the narrow range of the most common potash industry
applications.
• Computer simulation of the large industrial projects requires to use
some simplifications of OLI approach