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AFS Sand Casting ConferenceOctober 20-22, 2014 – Indianapolis, IN USA
Reclaimed Green Sand for
Core Room Application
Victor S. LaFay
S&B Industrial Minerals
Evaluation Completed at University of Northern Iowa by Jerry Thiel
AFS Sand Casting ConferenceOctober 20-22, 2014 – Indianapolis, IN USA
100% New Sand
50% New Sand
50% Reclaimed
Sand
20% New Sand
80% Reclaimed
Sand
100% Reclaimed
Sand
63 AFS GFN
65 AFS GFN
65 AFS GFN
65 AFS GFN
AFS Sand Casting ConferenceOctober 20-22, 2014 – Indianapolis, IN USA
Characteristics of the Sands
Sample ID Surface Area (cm2/g)
Coefficient
of Angularity
100% New Sand 236.764 1.433
50% New Sand
and 50%
Reclaimed Sand 249.273 1.43
20% New Sand
and 80%
Reclaimed Sand 216.054 1.236
100% Reclaimed
Sand 213.134 1.231
Shape Grain Shape Factor
Rounded 1.2
Semi-Angular 1.4
Angular 1.6
Compound No Factor Determined
AFS Sand Casting ConferenceOctober 20-22, 2014 – Indianapolis, IN USA
Characteristics of the Sands
Sample ID pH ADV
100% New
Sand 6.59 -0.667
50% New
Sand and 50%
Reclaimed
Sand 8.05 2.16
20% New
Sand and 80%
Reclaimed
Sand 8.92 3.833
100%
Reclaimed
Sand 9.16 5.067
Sample ID Conductivity (uS/cm)
Overflow Sand 835
Reclaimed Sand
after Processing 22
New Sand 10
AFS Sand Casting ConferenceOctober 20-22, 2014 – Indianapolis, IN USA
SEM of Molding Sand
Before Reclamation
AFS Sand Casting ConferenceOctober 20-22, 2014 – Indianapolis, IN USA
SEM of Molding Sand
Before Reclamation
AFS Sand Casting ConferenceOctober 20-22, 2014 – Indianapolis, IN USA
SEM of Molding Sand After
Reclamation
AFS Sand Casting ConferenceOctober 20-22, 2014 – Indianapolis, IN USA
SEM of Molding Sand After
Reclamation
AFS Sand Casting ConferenceOctober 20-22, 2014 – Indianapolis, IN USA
100
120
140
160
180
200
220
240
260
280
300
Immediate 5 min 1 Hr 4 Hr 24 Hr
Tensile
Str
ength
(psi)
Time
Tensile Strength Curves
100% New Sand
50% NewSand/50%Reclaimed Sand
20% NewSand/80%Reclaimed Sand
100% ReclaimedSand
AFS Sand Casting ConferenceOctober 20-22, 2014 – Indianapolis, IN USA
0.000
0.004
0.008
0.012
0.016
0.020
0.024
0.028
0.032
0 500 1000 1500 2000 2500 3000
Lin
ear
Expansio
n (
in/in)
Temperature (F)
S&B Minerals - Linear Expansion
100% New Sand 50% New Sand/50% Reclaimed Sand 20% New Sand/80% Reclaimed Sand 100% Reclaim
AFS Sand Casting ConferenceOctober 20-22, 2014 – Indianapolis, IN USA
1.0E+08
2.1E+09
4.1E+09
6.1E+09
8.1E+09
1.0E+10
1.2E+10
1.4E+10
1.6E+10
1.8E+10
0 500 1000 1500 2000 2500 3000
Surf
ace V
iscosity (
Pa.s
)
Temperature (F)
S&B Minerals - Surface Viscosity
100% New Sand 50% New Sand/50% Reclaimed Sand 20% New Sand/80% Reclaimed Sand 100% Reclaim
AFS Sand Casting ConferenceOctober 20-22, 2014 – Indianapolis, IN USA
Linear Expansion and
Viscosity Characteristics
Sample ID
Peak Expansion at
Alpha-Beta phase
transition (in/in)
Sinter Temperature
(F)
Peak Viscosity at
Sinter Temperature
(Pa.s)
100% New Sand 0.00897 2313.4 1.419 x 109
50% New Sand / 50%
Reclaimed Sand
0.00778 2143.7 1.240 x 109
20% New Sand / 80%
Reclaimed Sand
0.00643 2226.6 9.250 x 108
100% Reclaimed Sand 0.006 2294.3 9.621 x 108
AFS Sand Casting ConferenceOctober 20-22, 2014 – Indianapolis, IN USA
50% New Sand and 50%
Reclaimed Sand
AFS Sand Casting ConferenceOctober 20-22, 2014 – Indianapolis, IN USA
20% New Sand and 80%
Reclaimed Sand
AFS Sand Casting ConferenceOctober 20-22, 2014 – Indianapolis, IN USA
Summary
Step Cone Castings
Sample ID Veining Index Penetration Index
100% New Sand 28 26.75
50% New Sand / 50%
Reclaimed Sand
23 23.75
20% New Sand / 80%
Reclaimed Sand
20 16.25
100% Recalimed Sand 18 10.75
AFS Sand Casting ConferenceOctober 20-22, 2014 – Indianapolis, IN USA
Conclusions• Evaluations have shown that “overflow” green sand
can be reclaimed for use in the core room with a
phenolic urethane cold box organic binder.
• A simple but effective measure of the characteristics
of reclaimed green sand is clay content and acid
demand value.
• A reclamation process can reduce the angularity of
the sand grain as measured in the coefficient of
angularity.
AFS Sand Casting ConferenceOctober 20-22, 2014 – Indianapolis, IN USA
Conclusions
• In the tensile profile tests, 100% New Sand
showed higher tensile strengths than the
other samples.
• A decrease in tensile strength of about
20% was observed in the higher reclaim
sand content samples.
AFS Sand Casting ConferenceOctober 20-22, 2014 – Indianapolis, IN USA
Conclusions• With increasing addition of reclaimed sand to
new sand, a decrease in the peak expansion at
the alpha-beta phase transition was observed.
Similarly, a lower sinter temperature was also
observed for the reclaim sand blends.
• With regards to the step-cone castings, addition
of reclaim sand to the new sand improved veining
and penetration defects considerably with higher
amounts of reclaim sand displaying a lower
indication of these defects.