1.Introduction
2.Background
i. PCB Structure, Composition, Uses, Properties
- heterogeneous
ii. Brief Overview of Current Practises
- Flow diagram/words to describe process in general
iii. Drivers
a. Price
- Precious metals is main driver due to high prices
b. Resource Depletion
c. Social Responsibility
d. Increased disposal rates
- [“The rapid innovation in technology has resulted in availability of cheaper and better electronic products in the market making products obsolete faster and shortening the product life”]
e. Social Responsibility
f. Legislation
3. PCB Recycling
i. Pretreatment
a. Composition Analysis
- Techniques??
- Identify reusable parts
- AAS, ICP-AES
b. Disassembly/Dismantling
- They use lasers and stuff
- Reusable parts are shipped back to the market or OEM
- Removal of hazardous components
- Generally Manual (not economical)
- Research into auto and semi auto (Austria full scale)
ii. Separation/Concentration
- Shredding and crushing to reduce particle size ( find the optimum size)
- Separation methods
o Size
o Density
o Electrostatic
o Eddy (Al)
o Magnetic
o Gravitational
iii. Refining/Recovering
a. Hydrometallurgy
- Most metals are recovered at high efficiency
- Environmental impacts – effluents
- Different Chemicals used at different stages
o Fluoroboric acid for Solder
o Sulphuric/Nitric for Copper
o Cyanide for Gold (?)
Thiourea
Thiosulphate
Halides
o Alternatives
- For Metal/Non-Metal mixes use Leaching
- For Metallic mixes use electrochemical processes
b. Pyrometallurgy
- Smelting to recover copper, tin and lead
• waster generation: slag and ash, volume waste
• environmental impacts: global warming, acidification, photochemical ozone creation, and eutrophication
• resource draw: lignite, natural gas, crude oil, coal, aluminum, iron, and zinc
- Air Pollution
- Flame retardant properties of matrix
- Potential use of oil and gas effluents for fuelling system
What about substrate? Ceramics, Glass, Polymers! Out of scope?