IMOS Moldule 2 -Clay Review

UF IDS2935: Impact of Material Science Quest Fall 2024 Midterm: Modules 1-6

Properties of Clay

• high plasticity (manipulated at room temp.)

• good cohesion (maintains shape)

• high strength under compression (after drying and baking)

• poor tensile strength

• opaque

• insulator

• can be dried

• can be chemically transformed (heating above 1000C, shrinks, forms Si-O-Si bond)

Structure of clay

• Si has 4 bonds (Si-O-Si)

• Al has 6 bonds (Al-O-Al)

• Oxygen has 2 covalent bonds (Si-O-Al)

Kaolinite (China clay)

• 1:1 ratio (O-T-O-T)

• lower shrink to swell capacity

• heated <500C = drying can be reversed

• heated >1000C = stoneware dishes

Montmorillonite

• 2:1 ratio (T-O-T-interlayer-T-O-T)

• most common

• large shrink to swell capacity

Temper

non-plastic materials used to prevent shrinkage and cracking during drying and firing of vesels (ex. bone, charcoal, wood ash, sand, crushed sandstone, crushed limestone, crushed volcanic rock, crushed shells)

Primary v. Secondary clays

• primary: found at the site of formation

• secondary: washed downstream

factors for types of clay

• minerals

• glaciation

• ratio

Cuneiform

• oldest written story (2700 BC)

• account of King Ur’s superhuman strength and journey for immortality

• influence Illiad and Odyssey

History of clay

• Paleolithic: clay figurines

• Mesolithic: Japanese hunter-gatherers used clay pots for cooking

• Neolithic: sun-dried clay bricks in Israel, (oldest inhabited cities); crops stored in clay

• 7000 BC: Chatal Huyuk Clay Society

• 5000: potters wheel

• 4000BC: cuneiform tablets

Ancient uses of clay

• building materials (Great Ziggurat of Ur)

• writing

• cooking

• storage

• sling ammunition

• medical (Armenian bole medicine drink)

• musical instruments (ocarina flute)

Modern uses of clay

• sealing of oil drilling, landfills, and dams

• building materials

• odor absorbents

• pottery

• toothpaste

• cosmetics

• paint

• gasoline production

• papermaking

• cement production

• byproduct of phosphate mining

• chemical filtering

• organic farming

• quick-clot combat gauze

• hazardous waste clean-up

Carbon capture

• contains olivine (MgSiO4)

• traps Co2 into solid form

• captures up to 1/3 of weight in CO2

• could remove up to 1.7 trillions lbs of CO2 (5% of excess CO2 per year)

Affordances v. Constraints

• affordances: durable, hard, watertight, thermal conductivity

• constraints: brittle

Catalhoyuk clay society

mound settlement; entangled with clay

Theory of Entanglement

1. humans depend on things

2. things depend of things

3. things depend on humans (chains of interdependence)

4. humans depend of things that depend on humans/other things

Things

an assembling or bringing together of properties (potential and actualized)

Material entanglement

• influences social and cultural traits over time

• creates “thingworlds”

• new materials are selected if they fit within existing entanglements

• social change is not dependent on human intervention

Rare Earths

• not easily smelted

• hard to isolate

• often found in clay

• polluting to extract

• chemically similar (Sc, Y, La, Ce, Pr, Nd, Pm, Sm, Eu, gd, Tb, Dy, Ho, Er, Tm, Yb)

Uses of rare earths

• low-energy LEDs

• strong magnets

• wind turvines

• electrical vehicles

• polishing lgass

• alloying agent for stell

• phone LEDs

Extraction of rare earths

• China extracts 63%

  • byproduct of steel production

  • restricted exports and caused a the price spike

  • removed export restrictions and dropped worldwide prices

• source may not be sustanible (critical material)

Rare earth sustanibility

• massive recycling effort

• use less waste during extraction