Recycling In General Flashcards
Law of diminishing returns
A concept in economics which says that if one factor of production is
increased while other factors are held constant, the output per unit of the variable factor will eventually diminish. Although the marginal productivity decreases as output increases, this DOES NOT mean negative returns. Expressed as “the gain is not worth the pain.”
Economy of Scale & Diseconomy of Scale. What are their implications for the recycling industry?
Economy of Scale: Unit costs of recycling go down when the supply of waste material increases.
- 0.6 rule: Capital cost increases with a power of 0.6 of the production volume
Diseconomy of Scale: Unit costs of recycling go up when the number of different recyclable materials and applications increases. Due to:
- Demanding more expensive processing technology
- Supply shortage of feed
- Scheduling issues
- Other non-linear costs
Grade, recovery rate, and recyclability
Recovery rate:
- Percentage of marketable materials compared to the same materials in the feed (waste)
- A measure of separation efficiency
Grade:
- The purity of a material in the product fraction
- A measure of the product quality
Higher grade -> lower recovery rate
Higher grade -> higher processing cost
The relationship b/w recycling, waste management, sustainability, and economics
Recycling & waste management: Recycling is part of the waste management hierarchy. Although recycling helps conserving resources and reduces waste, there are economic and environmental costs associated with waste collection and recycling. => Recycling should only be considered for waste which can’t be reduced or reused.
Recycling & sustainability: Recycling extends the lifetime of resources and thus contributes to the sustainable development.
Recycling & economics: When materials become scarce, prices go up. Recycling slows down the decline in availability => positive effect on the price of the materials.
Factors influencing the recycling cost
- Capital investments - machinery
- Operational: A) Labour. B) Consumption of energy, water, materials.
- Raw materials: EoL products, waste
EoL Recycling Rate
How much available metals has been recycled.
EoL.RR = recycled EoL metal (old scrap)/EoL products
Recycled Content
RC = Recycling Input Rate. The share of recycled metal to the total metal input in refining. RC = (scrap used in fabrication (new & old scrap) + scrap used in production (new & old scrap))/(primary metal input + fabr. & prod. scrap)
Old Scrap Ratio
Ratio of the old scrap to the total
OSR = recycled EoL metal / (recycled EoL metal + scrap from manufacturing) = old scrap / (old + new scrap)
What is recycling? What types of recycling exist?
- Recycling is a materials recovery process from EoL consumer goods, byproducts, capital goods, and waste.
- Involves interconnected chain operations, like collection, transport, dismantling, size reduction, sorting and separation, chemical or metallurgical recovery.
- Starts in the design and manufacturing phase, in which materials selection and product complexity are important.
- Governed by policies, environmental regulations, and economics.
- Part of everybody’s daily life.
- Part of “circular economy”.
Up-cycling: recycling back to virgin materials quality (high value-added recycling), e.g. copper.
Down-cycling: recycling to lesser quality materials, e.g. plastics.
What are the benefits of recycling?
- Extension of resource life
- Energy savings
- Less pollutions of air (CO2) and water
- Reducing landfill
- Increasing employment opportunities
- Contribution to resource efficiency and a circular economy
What are the limitations of recycling?
Current needs are:
- Better product design
- Selection of materials which are more easily recyclable
- Reduction in use of critical materials
- Reduction in number of materials used
- Reduction in use of dissimilar materials
- Easy dismantling mechanisms, e.g. click systems and less joints
- More advanced machinery for physical separation
- More efficient end-processing technologies (chemical and metallurgical)
What role does economics play in recycling?
Profit = Market value - Recycling cost
Market value:
- Purity of recovered product
- Markets for recycled products
- Monetary value of the materials
Recycling cost:
- Logistics: collection and transport
- Processing: sorting and refining
- Disposal of residual materials
- Higher product complexity -> higher processing cost
Waste management hierarchy
The waste management hierarchy orders the different options for waste processing from most favoured (top) to least favoured (bottom); prevention, minimisation (reduction), reuse, recycling, energy recovery, disposal.
- Reduce: whenever possible, waste reduction is the preferable option.
- Reuse: if waste is produced, efforts should be made to reuse it if practicable.
- Recycling: helps conserve resources and reduce waste, but there are economic and environmental costs associated w/ waste collection and recycling.
- Recovery: it could be possible to recover energy from waste which can’t be reduced, reused or recycled.
How does product and materials complexity affect recyclability, the recycling cost, and operation?
The more complex a product is, i.e. many different or critical materials which are difficult to recycle, the higher the recycling cost, and the harder the operation.
