Transcript Chapter 5 Phase equilibrium

Chapter 5 Phase equilibrium
5 Phase equilibrium
5.1 Introduction
5.2 Equilibrium condition of heterogeneous system
5.3 Phase rule
5.4 Phase diagram of single component
5.5 Phase diagram of two components
5.6 Phase diagram of three components
5.1 Introduction
Phase
The part whose physical and chemical
properties are completely even is called
phase.
There is an obvious interface between
two phases, the change of microcosmic
properties in the interface is flight type.
The total system phase is called
phase number, we use  to stand for it.
5.1 Introduction
Gas
No matter how many gases commix,
there is only one gas phase.
Solid
Generally, one kind of solid has one
phase. No matter how evenly two
solid powder commix, they are still
two phases.
Phase Diagram
5.2 Equilibrium conditions in
heterogeneous system
In a closed multi-phases system, there
can be transition of heat, work and material.
There are four equilibrium conditions.
(1) thermo-equilibrium condition:
suppose system has phases α, β,…… , F
when it get equilibrium, every phases has
the same temperature.
T  T  
 TF
5.2 equilibrium conditions of
heterogeneous system
(2) pressure equilibrium condition:

p  p 
 pF
(3) Phase equilibrium condition:
B  B 
 FB
(4) chemical equilibrium condition:
 BB  0
B
5.3 Phase rule
5.3.1 Number of independent component
Definition:
C  S  R  R'
In the equilibrium condition, the independent
species number which can insure the
composing of every phases is called the
number of independent component.
5.3.2 Degree of freedom
The number of independent
intension variable which confirm
the equilibrium system state is
called degree of freedom, f.
These intension variable usually
called P, T, concentration and so
on.
5.3.2 Degree of freedom
If certain intension variable is
fixed, the other intension variable
except this variable is called
condition freedom degree, f*.
For example:
f  f 1
P is fixed
*
P and T are fixed,
f **  f  2
5.3.3 Phase rule
f F  C  2
Phase rule shows the relationship of
phase number  , independent
component number C and the free
degree f. “2” indicate usually two variables
T, P.
Phase rule discovered by Gibbs earliest.
5.3.3 Phase rule
If it affect by other force field besides
T and P, then 2 is instead by n, that is:
f F  C  n
Phase diagram
Phase diagram shows the multisystem state changes with the T,
P, composing and other intension
properties.
5.4 Phase diagram of single component
5.4.1 Some concepts
Phase point
The point which denote
certain phase state (such as,
composing, T, P, and so on).
5.4 Phase diagram of single component
material system point
The point in the phase diagram which denote
the system total state is called material system
point.
In the single phase section, material system
point and phase point are superposition; in the
two phase sections, it has only material system
point, its two corresponding phase composing is
denoted by corresponding two phase points.
5.4.1 Some concepts
Phase number and free degree of single component
system
C 1
f F  3
When F=1
single phase f=2
double variable system
F=2
bi-phases equilibrium f=1
single variable system
F=3
tri-phase coexist f=0
no variable system.
5.4.2 phase diagram of water
Three single
phase section
gas, liquid or
solid,
F  1, f  2
The certain independent change of T
and P will not arouse phase change.
5.4.2.2 Three two phase
equilibrium line
F=2, f=1 P and T can only
be changed one item, if the
P is fixed, the T is decided
by system.
5.4.2.3 Phase diagram
OA a gas-liquid bi-phase equilibrium
line
OB a gas-solid line
OC a liquid-solid line
OD the AO prolong line
Point O triple point,
three phase coexist,
F=3, f=0
5.4.2.4 Phase changing process
in the bi-equilibrium lines
Any point in the
two equilibrium line
Can have three
conditions. Such as
point P
in the line OA:
5.4.3 Triple point
H2O: T=273.16K, p=610.62Pa
When P=105 Pa,
ice point temperature
is 273.15K, change
outside pressure,
freezing point also
changes following it.
5.4.4 Slope in bi-phase equilibrium line
Slope of three bi-phase equilibrium
line can work out by equation of
Clausius-Clapeyron and Clapeyron .
Line OA
d ln p  vap H m

dT
RT 2
 vap H m  0
slope is positive
5.4.4 Slope in bi-phase equilibrium line
Line OB
d ln p  fus H m

dT
RT 2
 fus H m  0
Slope is positive
Line OC
dp  fus H m

dT T fusV
fus H  0, fusV  0
Slope is negative
Example A
5.5 Phase diagram of two components
P-x figure and T-x figure
Bi-liquid-system of ideal complete solution
Lever rule
Distillation principle
Bi-liquid-system of non-ideal complete solution
Bi-liquid-system of part solution
Bi-liquid-system of non-solution ----vapor distillation
Simple low eutectic mixture
System of forming compound
complete soluble solid
part soluble solid
Zone melting
5.5.1 p-x figure and T-x figure
For two components system,
C=2,
f=4-F ,
F is 1 at least, so f is 3 at most.
These three variable usually is T, P and
composing X. Therefore, if we need
solid figure of three coordinate to
express the diagram of bi-components
system state.
5.5.2 Bi-liquid-system of
ideal complete solution
Two pure liquids can dissolve each
other in various proportion, every
composing follows Raoult Law. Bi-
liquid-system of ideal complete
solution.
Such as benzene and toluene,
hexane and heptane.
5.5.2 Bi-liquid-system of
ideal complete solution
(1) P-X figure
P*A and P*B:
Pure liquid
saturation vapor
pressure;
P: total pressure.
pA  pA* xA
pB  pB* xB
p  pA  pB
5.5.2.2 p-x-y figure
pA
yA 
p
yB  1  yA
p  pA  pB  pA* xA  pB* xB
 pA* xA  pB* (1  xA )
 pB*  ( pA*  pB* ) xA
As we already know PA *, PB* , XA or XB ,
then we can work out the gas composing
which corresponding every liquid phase, draw
in the p-x figure, then we can get p-x-y
figure.
5.5.2.3 p-x-y figure analysis
If P*A >P*B ,
then, yA>xA ,
three areas:
L;
L+G;
G
5.5.2.4 T-x figure
Boiling-point -composing figure.
For certain composing solution, the
higher vapor pressure is, the lower
the boiling point is.
T-x figure can be drawed by the
experiment data directly and also
worked out from the p-x figure.
5.5.2.5 From T-x to p-x figure
 Benzene-toluene p-x

figure at four different
temp.
Draw a horizontal line
at the pressure P$
location.
Mark the relationship
of composing and
boiling point.
the bigger P* is, the
lower Tb is.
5.5.2.6 draw T-x figure
Use the methods
p
of y  p to work
out the gas
composing line.
gas line is above
the liquid phase line
A
A
5.5.2.7 T-p-x diagram
 Combine p-x and
T-x together.
Right side of
vertical plane,
xA=1, xB=0 Then,
PA* and TA*.
Left side, xA=0,
xB=1, then PB* and
TB*.
5.5.2.7.2 T-p-x diagram
The shuttle pattern
of concomitant gas-liquid
bi-phase moves along
two lines pA*-TA* and
pB*-TB* , the flat
Column space area is
the gas-liquid bi-phase coexist area,
5.5.2.7.3 T-p-x diagram
in the frontage above the coexist
area, it is the high temperature, low
pressure area, therefore, it is gas
phase area; in the coexist area
under behind, it is the low
temperature, high pressure area, it
is liquid phase area.
5.5.2.7.4 T-p-x diagram
In the solid figure,
all the verticals which
parallel with the most
front plane, then we
Can get the T-x figure;
All the section which
parallel with the most
above plane is isothermal plane,
then we can get the p-x figure.
5.5.3 Lever rule
DE: isothermal tie
line.
All of the material
system points in DE
are denoted by the
composing of point
D (Liquid) and E(Gas)
Material system point
is thought as pivot.
.
or
nl  CD  ng  CE
ml  CD  mg  CE
5.5.4 Distillation principle
Simple distillation
Simple distillation
can only detach
briefly A and B
of the bi-liquid
system.
5.5.4 Distillation principle
In the T-x figure of A and B, the
boiling-point of pure A is higher than pure
B, it shows that the content of B
composing in gas phase is higher when
distilling, the content of A composing in
liquid phase is higher too.
Simply distilling once, the substance
which has been distilled, composing B
will increase obviously, composing A in
residual liquid will increase too.
5.5.4.2 Simple distillation
bi-phase solution X1 ,
boiling when heating
to T1, the composing
of balanceable gas
phase is y1 (content
B increase).
5.5.4.2 Simple distillation
Condense the vapor which composing is
y1, content B in the liquid phase,
composing ascends along line OA, boilingpoint also ascends to T2, at this moment,
corresponding gas phase composing is y2.
Incept the the substance which has been
distilled between T1–T2, composing between
y1–y2 , residual liquid is x2, content A
increase. Thus, detach A and B briefly.
5.5.4.3 Fine distillation principle
Fine distillation,
rectification is the
Combination of many
steps of simple
distillation.
The bottom of rectify tower is heating area,
temperature is the highest one; The
temperature of the tower peak is the
lowest one.
5.5.4.3.2 Fine distillation principle
The rectification result, the collecting
composing which condensed in the peak of
the tower is the pure low boiling-point
composing, the pure high boiling-point
composing one left in the bottom of the
tower.
Rectification tower has many different kinds,
as the figure shows, it is the sketch map of
the rectification tower which is bubble covered
tower state.
5.5.4.3.3 Fine distillation principle
Use the T-x
figure of A, B
bi-composing to
express the
rectification
process.
5.5.5 Bi-liquid-system of
non-ideal complete solution
5.5.5.1 Positive deviation
to Raoult law
The broken line is theory
value, real line is
experiment value. Real
vapor pressure is
higher than calculated
value.
5.5.5.1.2 P-x(y) & T-x(y) figure
Draw the corresponding
gas composing line,
then we can get
p-x(y) figure and
T-x(y) figure. Liquid
phase line is no longer
beeline.
5.5.5.2 The peak in diagram
The positive warp is
so large, the highest
point in the p-x
figure is formed.
The one has highest
point in the p-x
figure, also has
lowest point in the
T-x figure.
The lowest point:
minimum azeotropic
point.
Azeotropes
5.5.5.2.2 Minimum azeotropic mixture
In the T-x(y) figure, the mixture
lies in the lowest-boiling azeotrope
is called minimum azeotropic mixture.
It is mixture not compound, which
composation in the fixed pressure
has fixed value. But the coposation of
lowest-boiling azeotrope chages with P,
T change of pressure. The systems:
H2O-C2H5OH; C2H5OH-C6H6
5.5.5.2.3 H2O-C2H5OH azeotrope
Combination of
two simple T-x(y) figure.
H2O-C2H5OH is 351.28K,
it contains ethanol
95.57. If the ethanol
content < 95.57,
absolute alcohol can not
be get.
The absorber CaCl2 ,
molecule siever can
make the ethanol
content excess 95.57.
5.5.5.3 Lowest point in p-x diagram
The one has
lowest point in the
p-x figure, also
has highest point
in the T-x figure,
the highest point
is called maximum
azeotropic point.
5.5.5.3.2 High-boiling azeotrope
In the T-x(y) figure, the mixture
lies in the highest-boiling azeotrope
is called maximum azeotropic
mixture.
The highest-boiling azeotrope
temperature of H2O-HCl is 381.65K,
it contains HCl 20.24. Usually, it is
used to be the standard solution in
chemical analysis.
5.5.6 Bi-liquid-system of
part solution
5.6.1 High critical consolute
temperature
H2O-C6H5NH2 system can
only dissolve with each
other partly, it is separated
into two layer. Underlayer
is the saturated anilin in water,
solubility is shown by the left
half; superstratum solubility
is shown by the right half.
5.5.6.1.2 High conjugate layers
Increase T, both of the
solubility will increase. At
point B, interface
disappears, become a
single liquid phase.
Inside cap, solution is
separated into two part.
At 373K, the composing
of two layers separately
are A’ and A’’, they are
called conjugate layers. An
is the average value.
5.5.6.2 Low critical
consolute temperature
water-three ethylamic
system
Lowest critical consolute
temperature TB: 291.2K
<TB: single liquid phase
>TB : bi-phase area.
critical consolute
temperature
Water and
nicotinic system
The lowest consolute
temperature 334K.
The highest consolute
temperature 481K.
5.5.6.4 No critical consolute temperature
Aether-water system
5.5.7 Bi-liquid-system of non-solution
5.5.7.1 Characters
The solubility between liquids A
and B is so small that it can be
ignored. So when A and B coexist,
vapor pressure of every composing
is the same as it exist by itself, the
total vapor pressure is equal to the
summation of two pure composing
saturated vapor pressure on the
liquid.
5.5.7 Bi-liquid-system of non-solution
5.5.7.1 Characters
The solubility
between liquids A
and B is so small
that it can be
ignored.
p p  p
*
A
*
B
5.5.7 Bi-liquid-system of non-solution
Cover a layer of water on the
mercury, attempt to decrease the
mercury vapor, it is furitless.
When two liquids coexist, its total
vapor pressure always large than the
vapor pressure of every composing,
While boiling-point is always lower
than the one of every composing.
5.5.7.2 Distillation of vapor
Water-bromine system
dissolving each other
is very small, while
the density difference
is very large.
5.5.7.2 Distillation of vapor
Material system
Vapor
pressure
curve
Bromine benzene QM
water
QN
Water+bromine
QO
benzene
Boiling
point
429K
373.15K
368.15K
5.5.7.2.2 Distillation of vapor
The substance after distilling, the compare
of the composing quality as following:
nB
p  py B 
nA  nB
*
B
*
B
*
A
p
nB mB / M B


p
nA mA / M A
nA
p  py A 
nA  nB
*
A
*
B
*
A
mB p M B


mA p M A
Though pB* is small, MB is big, so mB is
not too small.
5.5.8 Eutectic mixture
Thermal analytical method
Basis principle: two composing system C=2,
p=constant
f *  C 1   3  
 1
f * 2
double variable system
2
f * 1
single variable system
3
f * 0
non-variable system
5.5.8.1 Cooling curve
Cooling curve
change following
time during the
cooling process.
When new phase
agglomerates, it
discharge freezing
heat, slope of
cooling curve
changes. f*=0
horizontal appears.
5.5.8.2 Making Cd-Bi diagram
5.5.8.2.1 Step 1
Mark out the
melting point of pure
Bi (546K) and pure Cd
(546K) . At thismoment,
f *  C 1 F  11 2  0
When all of the melt curdled, F=1,
f*=1, temperature keeps on
dropping.
Step 1
5.5.8.2.2 step 2
20Cd-80Bi cooling curve
At point C, Bi(s)
separates out, the
cooling speed of
dropping turns slowly.
f *  C 1 F  2 1 2  1
At point D, Cd (s)
begins to separate
out, T=constant
f *  2 1 3  0
Similar for 70 Cd system.
Step 2
5.5.8.2.3 Step 3
40Cd-60Bi system
point E
f *  C 1 F  2 1 3  0
After E
f  2 1  2 1
*
5.5.8.1.3.2 Step 3
5.5.8.2.4 Step 4
Connecting point A,
C, E points.
ACE is the composition
line of bi-phase
Bi(s)+melt.
HFE: Cd(s) +melt
DEG: Bi(s) +Cd(s)+
melt (3 phases)
Step 4
5.5.8.2.5 Phase zone
1. Above line AEH,
melt phase f*=2
2. Inside ABE zone,
Bi(s)+melt, f*=1
3. Inside HEM zone,
Cd(s)+melt, f*=1
4. Under BEM zone,
Bi(s)+Cd(s), f*=1
5. Line BEM, f*=0
Bi(s)+Cd(s)+1
5.5.8.2.6 Important phase points
Point A, pure Bi (s) m.p.
Point H, pure Cd(s) m.p
Point E, the coexisting
point of tri-phases
Bi (s)+Cd (s)+l.
5.5.8.2.7 Eutectic mixture
and eutectic point
Point E is lower than point A and H,
it is called low eutectic point.
Low eutectic mixture is not compound,
it is composed by bi-phases, just
commixing very evenly. The
temperature of point E will change
following the changing of outside
pressure, in the T-x figure.
5.5.8.3 Water-salt diagram
Solubility method
H2O-(NH4)2SO4 system
Expressing salt solubility at
the different temperatures.
Above LAN, single phase l;
Inside LAB, ice+solution;
Above NAC, (NH4)2SO4 (s)+ l;
Under BAC, ice+(NH4)2SO4(s).
Water-salt diagram
5.5.8.3.2 special phase lines
Line LA: freezing point
dropping curve ice+ l.
Line AN, salt saturated
solubility curve
(NH4)2SO4 (s) + l
Line BAC, tri-phase
coexisting line
5.5.8.3.3 special phase points
L ice melting point.
but salt m.p. can’t be
expressed here.
A tri-phase coexisting
point
Ice+ (NH4)2SO4 (s)+ l.
If composition <A%,
first separates out ice;
If composition <A%, first
separates out salt.
5.5.9 System of forming compound
Two substances of A and B can form
two kinds of compounds:
(1) stabilization compound
It includes stabilization hydrated substance,
they have their own melting point, when
at the melting point, the composing of
liquid phase and solid phase are the same.
(2) non-stabilization compound
5.5.9.2 CuCl-FeCl3 Phase diagram
CuCl (A) and FeCl3 (B)
can form compound C;
The combination of two
simple low eutectic
phase diagram;
H is melting point of
C, adding A or B in C,
m.p. dropping.
5.5.9.2.2 CuCl-FeCl3 phase diagram
5.5.9.3 H2O-H2SO4 phase diagram
H2O and H2SO4 can
form three stabilization
hydrated substance,
that is
H2SO4  H2 O (C3 )
H2SO4  2H2 O (C2 )
H2SO4  4H2 O (C1 )
the combination of four simple bi-phase
low eutectic phase diagrams.
5.5.9.3.2 H2O-H2SO4 phase diagram
5.5.9.4 CaF-CaCl phase diagram
CaF2(A) and CaCl2(B) form
non-stabilization C .
Heating C up to point O,
it decomposes and the
melt composation is N.
Therefore, this temperature
is called peritectic
temperature.
FON: tri-phase line: A(s),
C(s) and N (melt). N is at
the end, not in middle.
5.5.9.4.2 CaF-CaCl phase diagram
5.5.9.4.3 Analysis of phase diagram
In OIDN, C(s) and
melt (L) bi-phase.
Line a:
L  A(s)  L  A(s)  C(s)  L(N)  A(s)  C(s)
Line b
L  A(s)  L  A(s)  C(s)  L(N)  C(s)
Line c
L  A(s)  L  A(s)  C(s)  L(N)  C(s)  L
 C(s)  B(s)  L(D)  C(s)  B(s)
5.5.10 Diagram of complete
soluble solid
Two composing can
dissolve each other in
solid/liquid state, not
to form compound
and low eutectic point.
Analysis A, in bi-phase,
Au m.p. is higher than
Ag, Au content in solid
phase is more, less
in in liquid phase.
5.5.10.2 Branch crystal,
annealing and quenching
Solid-liquid bi-phase is different from the gasliquid bi-phase, crystal is not easy to get
equilibrium with melting substances. the
crystal separated earlier contains more higher
m.p. composition, forming branch crystal, the
later one contains lower m.p. composition.
Branch crystal phenomenon.
Annealing process
5.5.10.3 Diagram with
extreme value
Diagram with the
lowest or highest
point.
When the particles
size of two composing
and the crystal
structure are not
completely same, the
lowest/highest point
will appear in their Tx figure.
5.5.11 Diagram of part
soluble solid
Two composing can dissolve each other
infinitely in liquid state, but only partly in
solid phase, forming the cap pattern area.
Outside the cap pattern area, it is the
single phase soluble solid, inside it, it is the
bi-phase coexisting of two soluble solid.
two types:
(1) there is one low eutectic point,
(2) there is a changing m.p temperature.
5.5.11.2 Diagram with
eutectic point
single phase:
Above line AEB (L)
AJF Left, soluble solid (1)
BCG Right, soluble solid (2)
bi-phase areas:
Area AEJ, L+(1)
Area BEC, L+(2)
Area FJECG, (1）+（2）
AE, BE: liquid phase lines;
AJ, BC: solid composing lines;
5.5.11.2 Diagram with
eutectic point
line JEC: the tri-phase coexisting line,
(1)+ (2)+L
point E: the low eutectic point.
The degree of two soluble solid
dissolving each other can be found
out from line JF and CG.
5.5.11.2.2 Analysis of phase diagram
 From point a
 From point e:
Melt L  L +（1）
（1）（1）+（2）
From point j:
L  L +（1）(1) +
（2）+L（composing
is E )  (1) +（2）
5.5.11.3 Diagram with
transition temperature
 single phase : BCA Left; L
Area ADF, (1);BEH Right, (2)
Bi-phase areas: BCE
L+(2); ACD L+(1); FDEG
(1)+(2)
Because this kind curve
is difficult to measure, it
is denoted by broken line.
5.5.11.3.2
5.5.11.3.3 Analysis of phase diagram
CDE: tri-phase line:
Melt (composing C)
+(1) (composing D)
+(2) (composing E).
CDE transition temperature,
over this T, solid solution
(1) disappears and
changes into the melt
(composing C) and solid
solution (2) ( composing
E).
5.5.12 Zone melting
Zone melting is the availability methods of
preparing high pure substance.
Cover the high frequency heating loop on one
end of stick material which needs refined,
melting down some part of it, then heating
loop advance forward slowly, the part which
already melted re-curdle again.
5.5.12.1 Coagulation coefficient
Impurity concentration in solid
phase and liquid phase separately
are Cs and C1 , the coagulation
Cs
coefficient is Ks:
K 
s
Cl
5.5.12.1 Coagulation coefficient
Ks<1 The concentration of impurity
in liquid phase more than solid phase.
If heating loop moves from the left
to the right, impurity concentrate on
the right end.
5.5.12.1.2 Coagulation coefficient
Ks<1 The impurity
concentration in liquid
phase more than solid
phase. impurity makes
Material m.p. decrease.
When heating to point P, it begins to
melt, the impurity concentration is C1 .
After the heating loop is moved, the
solid (composing N, the impurity
concentration Cs.) begins to separate
out.
Because Ks<1, Cs<C1 , the
impurity in solid phase is fewer
than before, impurity moves to the
right end along the heating loop.
5.5.12.1.3 Coagulation coefficient
The condition of
Ks  1
5.6 Phase diagram of three
components
Because C=3, f=3+2-Ф
When Ф=1 f=4 , it can not be denote by
the phase figure.
When Ф=1, isotonic, f*=3 ( or f*=3
isothermal), use normal tri-prism to denote,
the normal triangle on the underside stands
for the composing, the high of the pole
stands for the temperature or pressure.
5.6.1 Expression of three
components
On equilateral
triangle, mark
three peaks
along the
counterclockwise
direction, three peaks separately stands
for pure composing A, B and C,
5.6.1 Expression of three
components
The points on the three sides
stands for the quantity fraction of
the corresponding composings. All of
the points in the triangle stands for
the tri-composing system. Lead
parallel lines of every sides through
point O in the triangle at random,
5.6.1 Expression of three
components
the distance which is cut in every
sides stands for the content of the
corresponding peak composing, that is,
a’ stands for the A content in O, the
same reason, b’ , c’ separately stands
for the B and C contents in the
system which denoted by O.
Obviously, a'b'c'  a  b  c  1
5.6.1.2 Expression of three
components
(1) on every lines
which parallel the
hemline, all the point
which stands for the
material system, the
peak composing
quantity fraction are the same.
5.6.1.2 Expression of three
components
Such as, material system point d,
e, f, the quantity fraction which
contents A are the same.
(2) On the line which goes
through the peak, the ratio of other
two composings are the same. Such
as, on line AD, c' '  c'
b' '
b'
5.6.1.2 Expression of three
components
(3) on every line which goes through
the peak, the nearer it approaching the
peak, the more content which stands for
the peak composing; the farther it is, the
fewer content is. Such as, on line AD,
content A in D’ is more than D
5.6.1.3 Expression of three
components
(4) if point D and E which stands
for two tri-phase composing systems,
commix into a new system, the
material point O of it must lies on the
linking line DE. Which material system
content is more, point O approaches
which material system point.
5.6.1.3 Expression of three
components
The location of
point O can be
worked out by lever
rule. Use mD, mE to
stands for the
quantity of D and E,
therefore: mD  OD  mE  OE
5.6.1.4 Expression of three
components
(5) the material system
point of new system
which commixed by
three tri-phase system D,
E, F, it lies in the
triangle location
barycenter which
compose by this three
points, that is point H.
5.6.1.4 Expression of three
components
Use lever rule to work out
material system point G of new
system which commixed by D and E
firstly, then use lever rule to work
out material system point H of new
system which commixed by G and F,
H is the barycenter of DEF.
5.6.1.5 Expression of three
components
(6) suppose S is the tricomposing liquid system, when
separates out composing A from S,
the residual liquid phase composing
changes along the extending line
AS, suppose it get B.
5.6.1.5 Expression of three
components
The A quantity
which separates out
can be work out by
lever rule:
mA  AS  mB  bS
If adding Composing A in b, the material
system point moves towards peak A.
5.6.2 System of part
soluble in three-kind liquids
(1) there is a pair
partial soluble system,
both acetic acid (A),
chloroform (B) and
acetic acid , water (C)
can commix infinitely,
but chloroform and
water can dissolve
each other partial.
5.6.2 System of part
soluble in three-kind liquids
There is a cap pattern area on the
tri-composing system phase diagram
which composed by them, between a
and b, solution is divided into two
layer, one layer is under the exists of
acetic acid , the saturated liquid of
water in chloroform, as it shows by a
5.6.2 System of part
soluble in three-kind liquids
serious of point a; anther layer is
the saturated liquid of chloroform in
water, as it shows by a serious of
point b. This pair is called
conjugation solution.
Example B
5.6.3 T-x1-x2 diagram
Draw the pair of
part soluble system
which is in the
tri-solution to a
Positive tri-prism solid
figure, vertical coordinate
is temperature, every
level section is the
positive triangle composing figure.
5.6.3 T-x1-x2 diagram
Temperature keeps on increasing,
soluble degree also increases, the cap
pattern area which bi-liquid phase
coexists keep on reducing, at last, it
get point K, form a single even
phase. Connect all the transversals
which under the isothermal condition
to a bend face, inside the bend face
is the bi-phase area.
5.6.4 Exaction principle
For the liquid mixture
which boiling-point
approaching or the
one which has
co-boiling phenomenon,
it can be used
extraction to separate.
For the separation of
Aryne and alkane,
usually use di-glycol ester as extracter.
5.6.4 Exaction principle
It can be seen from the phase figure,
aryne A and alkane B completely dissolve
each other, aryne A and extracter S also can
dissolve each other, while the solubility of
alkane and extracter is very small.
Usually according to the distribution coefficient
to choose the appropriate extraxter.
5.6.4.2 Exaction principle
Put A and B mixture
which composing is F
into distributed funnel,
adding extracter, shaking,
material system point
moves along line FS,
suppose getting point
O ( according to the quantity of S by the
lever rule calculating ), placing till delamination.
5.6.4.2 Exaction principle
Extraction phase composing is y1, remove
S by distillation, material system point
moves along Sy1, till point G, at this
moment, the content aryne is higher than
point F obviously.
Extraction phase composing is X1, remove
S by distillation, material system point
moves along Sx1, till point H, at this
moment, the content alkane is higher than
point F.
5.6.5 Water-salt system of
three components
(1) The system of
solid salt B, C and
water ( two kinds
of salts have a
common ion, avoid
forming the alternate
system which has not only two kinds salts
by the ions interaction ). In the picture:
5.6.5 Water-salt system of
three components
One single phase area
ADFE is the non-saturated solution
single phase area.
Two bi-phase areas
BDF is the bi-phase coexist area
of B (s) and its saturated solution;
5.6.5 Water-salt system of
three components
CEF is the bi-phase coexist area
of C (s) and its saturated solution.
One tri-phase area
BFC is the tri-phase coexist area
of B (s), C (s) and the saturated
solution which composing is F.
5.6.5.2 Water-salt system of
three components
(1) The system of solid salt B, C
and water, in the figure:
Two special lines:
Line DF is the solubility curve of
B in the water solution which
contains C; line EF is the solubility
curve of C in the water solution
which contains B.
5.6.5.2 Water-salt system of
three components
One tri-phase area:
F is the tri-phase
point, tri-phase of
saturated solution
and B (s), C (s)
coexist, f**=0
Several linking lines
The several linking lines of B and DF as
well as C and EF are called linking lines.
5.6.6 Purifying salt
If the composing
of the mixture
which composed
by two kinds of
salt B and C is
point Q, how to separate B?
5.6.6 Purifying salt
We should add water firstly, get
the material system point moving
along the direction QA, go to point
R from area BDF, C (s) dissolve
completely, the left is pure B (s),
filtrate, drying, then we can get
pure B (s).
5.6.6 Purifying salt
The more point R approaching line BF,
thus the more pure B (s) can be get.
The appropriate quantity of water which is
added and the B (s) which we can get
may be used to calculate by lever rule.
If point Q is on the right of line AS, use
this methods to get pure C (s).
5.6.7 Eutectic mixture of
three components
Metal Sn, Bi and Pb
can form three bi-phase
low eutectic phase
diagram each other,
their low eutectic point
are separately E1, E3 and
E2, the position of low
eutectic point in the hemline
composing line are separately C, D and B.
5.6.7 Eutectic mixture of
three components
Folding the ichnography towards to
the middle, make three hemlines SnBi, Bi-Pb and Pb-Sn which stands for
the composing form the positive
triangle, then we can get the triphase low eutectic phase diagram of
three-dimensional positive prism,
vertical coordinates are temperature.
5.6.7.2 Eutectic mixture of
three components
One single phase area
Above the
anadem bend
face is the
solution single
phase area;
5.6.7.2 Eutectic mixture of
three components
Three bi-phase area
On the three bend face are the
bi-phase coexisting area of solution
and the solid of corresponding peak
substance
Three tri-phase coexisting point
At every low eutectic points E1,
E2, E3, is tri-phase coexist.
5.6.7.3 Eutectic mixture of
three components
If adding Bi at point
E2, low eutectic point
keeps on dropping,
when getting E4,
there are metal Bi
separates out
( adding Sn in E3,
adding Pb in E1 both
have the similar conditions ).
5.6.7.3 Eutectic mixture of
three components
One four phases point
E4 is four phases point which coexist
by four phases of Sn (s), Pb (s), Bi (s)
and the solution which composing is E4,
at this moment, f*=0 , the location of E4
has fixed value under the fixed pressure.
When temperature keeps dropping, liquid
phase disappears, three solid coexist.
ending