reclaimed green sand for core room application€¦ · afs sand casting conference october 20-22,...

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


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


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


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


SEM of Molding Sand

Before Reclamation


SEM of Molding Sand After

Reclamation


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


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


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


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


100% New Sand


50% New Sand and 50%

Reclaimed Sand


20% New Sand and 80%

Reclaimed Sand


100% Reclaimed Sand


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


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.


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.


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.


Questions and Answers

reclaimed green sand for core room application€¦ · afs sand casting conference october 20-22,...

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