Post on 04-Jan-2016
description
Emissions from melted glass: experimental and theoretical approaches
MAKAROV Pavel2st year master student MSU
Trainee in SGR: 18/03/2013 – 31/07/2013
Supervisors: BLAHUTA Samuel
CONDOLF Cyril
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INTRODUCTION
2
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Key questions
What gaseous species are the most stable during volatilization of glass in Na-B-Si-O(-H) system according to literature data?
What thermochemical databases do we have?
Are current databases convenient for simulation of experimental processes?
3
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Literature survey on the most stable gaseous species in high temperature (1700 – 1800 K) region;
Volatilization experiments (binary, ternary glasses);
Thermodynamic simulation (FactSage) of the experiments;
Comparison of experimental results to FactSage simulation;
General conclusions;
Perspectives.
Summary of presentation
4
NaBO2, HBO2 (+NaOH)1
2
3
4
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5
Poor agreement of FactPS and experimental dataIn high temperature region
• Data for NaBO2 (g) were modified (based on FactPS data);• New database FactTEST was created;
NaB
O2
(g) p
arti
al p
ress
ure
(l
og
)
1000/T, K-1
(1) NaBO2 (g): literature data, comparison to FactSage
Cole et al., 1935
Cable et al., 1987 Gorokhov et
al., 1971
Nalini et al., 2008
Ivanov, 2002
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(1) How to build new database?
NaBO2 (l) ↔ NaBO2 (g)
6
∆G = G(NaBO2(g)) – G(NaBO2(l)) = - RT lnKeq
Keq = P(NaBO2(g))/a(NaBO2(l))a(NaBO2(l))=1
_____________________________________∆G = G(NaBO2(g)) – G(NaBO2(l))= - RT lnP(NaBO2(g))
1) Thermodynamic description
2) Experimental descriptionlg P = A + B/T
Literature dataFactSage (SLAGA)
?
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(1) NaBO2 (g): literature data, comparison to FactSage
7FactTEST is also efficient for Na2O/B2O3 system with
different compositions
NaB
O2
(g) p
arti
al p
ress
ure
(l
og
)
1000/T, K-1
2 B2O3 + Na2O
Cole et al., 1935
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(1) HBO2 (g): literature data, comparison to FactSage
8
FactPS: Good agreement to Knudsen effusion mass-spectrometric method data;
HB
O2
(g) p
arti
al p
ress
ure
(l
og
)
1000/T, K-1B2O3(s) + H2O(g):
1960
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(1) HBO2 (g): literature data, comparison to FactSage
9
FactPS: Good agreement for values obtained from transpiration method;
Eq
uili
bri
um
co
nst
ant
(lo
g)
T, K
B2O3 (l) + H2O (g) = 2 HBO2 (g)
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(1) HBO2 (g): literature data, comparison to FactSage
10
FactPS calculation results in agreement with experimental (Knudsen effusion method) at different T;
0.5 H2O (g) + 0.5 B2O3 (l or s) = HBO2 (g)
y = x
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(1) Conclusions on thermodynamic databases?
thermodynamic functions for NaBO2 (g) modified; new database (FactTEST);
thermodynamic functions for HBO2 (g) – no change; still using FactPS.
11
CONFIDENTIAL - Disclosure or reproduction without prior written permission of Saint-Gobain Recherche is prohibited.
Literature survey on the most stable gaseous species in high temperature (1700 – 1800 K) region;
Volatilization experiments (binary, ternary glasses);
Thermodynamic simulation (FactSage) of the experiments;
Comparison of experimental results to FactSage simulation;
General conclusions;
Perspectives.
Summary of presentation
12
2
3
4
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(2) Experimental set-up
Conditions: T = 1475 °C, P(H2O) = 0,19 & 0,65 bar;
Glass: 1) binary (26 wt. % Na2O, 74 wt. % SiO2);
2) ternary (26 wt. % Na2O, 5 wt. % B2O3, 69 wt. % SiO2);
13Flacons with deionized water
Quartz fiber filter
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(2) What changes during the experiment?
14
Initial composition
of glass
Composition of g
lass
changes d
uring th
e
experim
ent
5 series of solutions for each hour was analyzed with ICP
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(2) Analyses used, sample preparation
ICP (for all solutions);
pH – measurments;
μprobe analyses;
SEM/EDS (additional);
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Ci in each solution
Final glass composition,
concentration profiles
Verification of ICP & μprobe
Verification μprobe
Gas / melt composition on each step
CONFIDENTIAL - Disclosure or reproduction without prior written permission of Saint-Gobain Recherche is prohibited.
Literature survey on the most stable gaseous species in high temperature (1700 – 1800 K) region;
Volatilization experiments (binary, ternary glasses);
Thermodynamic simulation (FactSage) of the experiments;
Comparson of experimental results to FactSage simulation;
General conclusions;
Perspectives.
Summary of presentation
16
3
4
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(3) Thermodynamic simulation (FactSage) of volatilization experiments
17
ICP - output FactSage
simulation
comparison
Qi = ΣQ(i elem)
Input for FactSage
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(3) Ternary glass: working assumption
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ICP result recalculation: Main assumption - NaOH amount is negligible
Na
B
NaBO2
HBO2
ICP: Ci in each solution
Pj we want to
calculate
CONFIDENTIAL - Disclosure or reproduction without prior written permission of Saint-Gobain Recherche is prohibited.
Literature survey on the most stable gaseous species in high temperature (1700 – 1800 K) region;
Volatilization experiments (binary, ternary glasses);
Thermodynamic simulation (FactSage) of the experiments;
Comparison of experimental results to FactSage simulation;
General conclusions;
Perspectives.
Summary of presentation
19
4
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(4) Binary glass: experiment vs FactSage
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0,19 bar 0,65 bar
Time ↑
NaO
H (g
) par
tial
pre
ssu
re
(lo
g)
Time ↑
NaO
H (g
) par
tial
pre
ssu
re
(lo
g)
FactSage simulation results are close to experimental points
Na, Si
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21
P (H2O) SiO2,
wt. %
Na2O,
wt. %
0.19 bar 73.2 16.8
0.65 bar 73.6 17.4
μprobe
SiO2
Na2O
(4) Binary glass: experiment vs FactSageNa, Si
ICP
µprobe
1) Flat profiles (µprobe) → it’s possible to recalculate melt composition from ICP results;
2) Differs between w(Na2O) for ICP and for µprobe.
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(4) Binary glass: experiment vs FactSage
22
?
EDS
1) Precipitation during cooling of melt;2) Precipitate absorbs Na from glass matrix.
Na, Si
Black particles
SiO
Na Glass matrix
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(4) Ternary glass: experiment vs FactSage
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Na, Si, B
T = 1475 °C
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(4) Ternary glass: experiment vs FactSage
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ICP analysis
FactTEST is not suitable because of problems with mass balance at phase equilibrium calculation (reason – G(T) for NaBO2 (g) in FactTEST)
Na, Si, B
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(4) Ternary glass: experiment vs FactSage
25
Cross section plotting
Na, Si, B
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(4) Ternary glass: experiment vs FactSage
26
NaBO2 HBO2
1) FactPS results are in agreement with ICP for NaBO2 (g);2) Differs for HBO2 (g) at 0,65 bar: Possible reasons: - not all condensate was collected in experiments;
- deffects of thermodynamic glass model in FactSage.
Na, Si, B
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27
μprobe
SiO2
Na2O
(4) Ternary glass: experiment vs FactSage
ICP µprobe
1) Flat profiles (µprobe);2) Differs (less than for binary glass) between w(Na2O) for ICP and for
µprobe.
Na, Si, B
P (H2O)
SiO2,
wt. %
B2O3,
wt. %Na2O,
wt. %
0.19 bar
72,9 1,6 19,8
0.65 bar
73,2 1,6 20,9
B2O3
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(4) Ternary glass: experiment vs FactSage
28
EDS
1) Precipitation during cooling of melt;2) Precipitate absorbs Na from glass matrix.
Na, Si, B
Black particles
O Si
Na Glass matrix
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(4) Industrial glass (SGR, 2009)
Insulation glass (wt. %):
SiO2 = 65.6
Al2O3 = 2
B2O3=4.3
CaO=8
MgO=2.7
Na2O (+K2O)=17.0 (K2O=0.6 put as Na2O)
T = 1475 °C, P(H2O) = 0,19 bar
29
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(4) Industrial glass (SGR, 2009)
30
1) FactPS can be approached for experiment simulation;2) FactTEST is not suitable.
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(4) Industrial glass (SGR, 2009)
31
NaBO2 HBO2
The same magnitudes for Pi like in our experiments → Differs for HBO2 (g) for ternary glass at 0,65 bar could be explained by problems of
theoretical glass model in FactSage;
CONFIDENTIAL - Disclosure or reproduction without prior written permission of Saint-Gobain Recherche is prohibited.
Literature survey on the most stable gaseous species in high temperature (1700 – 1800 K) region;
Volatilization experiments (binary, ternary glasses);
Thermodynamic simulation (FactSage) of the experiments;
Comparison of experimental results to FactSage simulation;
General conclusions;
Perspectives.
Summary of presentation
32
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General conclusionsAccording to literature analysis:
- Thermodynamic properties of NaBO2 (g) in FactPS were modified;
- New FactTEST database was created;
- Properties of HBO2 (g) are in good agreement with literature data;
Volatilization experiments were carried out;
FactTEST can not be used for real experiment simulation;
Initial database FactPS was recommended to be used for experiment optimizing.
33
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PERSPECTIVESVerification of Tboiling of pure NaBO2 (g) (literature – 1434°C, FactPS – 1757°C);
Check SLAG database on data correctness, creating new database/ new solution model for glass melt in Na2O-B2O3-SiO2 system;
34
NaB
O2
(g) p
arti
al p
ress
ure
(l
og
)
1000/T, K-1
1757°C1434°C