TECNOLOGIA DOS MATERIAIS CERÂMICOSweb.ist.utl.pt/ist12456/6. DRYING.pdf · 2018. 11. 30. ·...

TECNOLOGIA DOS MATERIAIS CERÂMICOS

VI – DRYING

TECNOLOGIA DOS MATERIAIS CERÂMICOS M. Clara Gonçalves 2015

PRESSING FILTER

RAW MATERIALS

SLIP CASTING

DRYING

FINISHING

SINTERING

GRANULATION SPRAY DRYING

PRESSING

CLASSIFICATION

WASTE

ADITIVES DOSAGE

GRINDING AND/OR DRY MIX

GRIDING AND/OR WET MIX

ADITIVES

WASTE

PLASTIC FORMING


I-WET ROUTE II-DRY ROUTE

http://www.google.pt/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0CAcQjRxqFQoTCMOoipP-5MgCFcjaGgod7YMLSQ&url=http://www.alibaba.com/product-detail/Vacuum-304-Stainless-Steel-Ball-Mill_60124056872.html&psig=AFQjCNEBK_eMlcy510JYX6h7u3j9HdxcIw&ust=1446115447785688

http://www.google.pt/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwigwIDwg6fJAhWGfRoKHaCJDv8QjRwIBw&url=http://spray-dryer.com/designs/elements/&bvm=bv.108194040,d.d2s&psig=AFQjCNG_xFRet3HIk6gr6_8DmQxl4mRksA&ust=1448384738357725

http://durand.com.au/claymaking.html

http://www.aadvancedmach.com/inventory/Jars_Ball_Pebble_Mills/AA-6292-Paul_O._Abbe.html

http://www.google.pt/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0CAcQjRxqFQoTCI7C6aC-zsgCFQpVGgodehEBMg&url=http://www.guptagrinding.com/kaolin-powder.htm&psig=AFQjCNHdkXMJrt0ewC3JkQpUpb-gyJyuDg&ust=1445342209995335

http://www.google.pt/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0CAcQjRxqFQoTCOmTiaeL5cgCFQI_Ggodg0ABhg&url=http://www.ceramicmaterials.saint-gobain.com/products/ceramic-grains.aspx&psig=AFQjCNFZA-WZHwn-Mz255cw_MOS6WuLLWQ&ust=1446119014853777

http://www.google.pt/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0CAcQjRxqFQoTCIvL-ef61cgCFQk_Ggod_eAGLw&url=http://digitalfire.com/4sight/material/ball_clay_80.html?logout%3Dyes&bvm=bv.105814755,d.d2s&psig=AFQjCNFNAhoqnhw2JPjcI5Z-DzXxgp66Ow&ust=1445599180393962

http://www.lippert.de

Drying


Drying


Drying


http://www.google.pt/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwjZt8XTzNnJAhXJWhoKHZUxD5gQjRwIBw&url=http://www.keramverband.de/brevier_engl/4/1/4_1_4.htm&psig=AFQjCNHFHGB15Rvicc9A1o6qI6A-75NLbA&ust=1450122256803982

http://digitalfire.com/4sight/glossary/glossary_firing_shrinkage.html

http://earthwork7.blogspot.pt/2011_09_01_archive.html

Drying: what could go wrong?

Crasks !


Linear/volumic deformation !



Warping !

http://www.fireverseceramics.com/clay-memory-and-movement.html



http://www.ceramicindustry.com/articles/82979-lean-drying

Drying: inside the drying chamber


H2O H2O

H2O

H2O

H2O H2O

air in movement

static air with high relative humidity

surface continuous liquid film

Risk of water saturation!

T Tboiling

T Tboiling

Liquid evaporation rate = f( T , liquid surface area)

= 1/f (liquid concentration in air)

Liquid evaporation rate = f( velocity of Q transfer into the system)

f (liquid concentration in air)

Drying


Critical moisture content (CMC) corresponds to

the termination of shrinkage. Until CMC a

superficial liquid film is distributed uniformly

throughout the volume.

What really happens at this point?

At CMC the superficial liquid film is interrupted!

Liquid evaporation is no more controlled by T

(and liquid film surface area) but by liquid

diffusion from interior towards exterior of

ceramic piece.

Drying


(CMC)

(CMC)

A

B

C D


A B

C D

Drying



A B

C D

air

(CMC)

Drying


A B

C D

A

B

C D


(CMC)

(CMC)


Drying


A B

C D

(CMC)



Risk of water saturation!

http://www.ceramicindustry.com/articles/82979-lean-drying

Drying: inside the drying chamber


H2O H2O

H2O

H2O

H2O H2O

static air with high relative humidity

Drying


Drying


http://www.google.pt/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwjZt8XTzNnJAhXJWhoKHZUxD5gQjRwIBw&url=http://www.keramverband.de/brevier_engl/4/1/4_1_4.htm&psig=AFQjCNHFHGB15Rvicc9A1o6qI6A-75NLbA&ust=1450122256803982

Sintering


Further reading

Ceramic Processing and Sintering. M. N. Rahaman CRC Press (2003)

Sintering of Ceramics – New Emerging Techniques. Arunachalam

Lakshmanan (Ed.) INTECWEB.ORG (2012)

TECNOLOGIA DOS MATERIAIS CERÂMICOSweb.ist.utl.pt/ist12456/6. DRYING.pdf · 2018. 11. 30. ·...

Documents

Transcript of TECNOLOGIA DOS MATERIAIS CERÂMICOSweb.ist.utl.pt/ist12456/6. DRYING.pdf · 2018. 11. 30. ·...