03 matl recycle - ncsu coe people matl recycle.pdf · • manufacturing is cheaper (energy,...

1Copyright Anders Damgaard & Morton A. Barlaz, NC State University

Material recycling• Outline

– Objective of material recycling– Purpose of reuse in industry– Recycling Components of the MSW Stream

• Aluminum• Glass• Steel• Plastics• Paper• Tires

Copyright Anders Damgaard & Morton A. Barlaz, NC State University


Objective

• Examine recycling process for each material, alternative technologies, projected markets– Demand and economics have a significant influence on

recycling activity• Is it consistently marketable?• What limits recycling?


Purpose of reuse in industry

• Ensure raw materials to national industry: Paper, glass, metal.• Economy: Waste materials are cheaper than virgin materials at the

gate of the plant (price of raw materials, transport of raw materials)• Manufacturing is cheaper (energy, emissions, waste & costs)• Life-cycle assessment shows overall benefits (less virgin materials

used, less landfilling and maybe less treatment)

In the latter case, global assessment may be different than that of theindustry and regulations / incentives may be needed to improve recycling


Paper and paper products:Short version

• Paper is primarily based on wood fiber (renewable)• Paper recycling in terms of damaged products and converter´s

waste has a long history. Characteristics: large quantities from the individual source, defined quality and clean

• Problems with post-consumer paper: Ink/printing, fiber length, composite materials, foreign objects (clips, tape, strings, etc.)

• Major benefits: Savings in wood and pulp production (upstream activities)

• Products: Newspaper, tissue, cardboard, etc.


Paper: Remanufacturing 1Chemical-mechanical re-pulping• Chemical-mechanical re-pulping is used for higher-quality products requiring

removal of ink and maybe bleaching. Chemical-mechanical re-pulping including the cleaning process typically consists of seven steps (Virtanen & Nilsson, 1993):

– Feeding and pulping including pH adjustment (caustic soda, aluminum sulfates) and addition of dispersing agent (e.g. glycol ether)

– Pre-cleaning (mechanical) removes solid foreign items using centrifuges and pressure sorters

– Refining provides washing, sorting and milling of the pulp– De-inking and pigment removal by chemical (water glass, etc,) and mechanical

(flotation) treatment steps.– Final cleaning (mechanical) – Thickening and bleaching (heating with hydrogen peroxide or sodium

hypochlorite) and storing– Drying


Paper: Remanufacturing 2

• Mechanical re-pulping• Mechanical re-pulping is used for less demanding paper qualities such as brown

paper, boards, egg containers, etc. Mechanical re-pulping including the cleaning process typically consists of six steps (Virtanen & Nilsson, 1993):

– Feeding and pulping including pH adjustment (caustic soda, aluminum sulfates) and addition of dispersing agent (e.g. glycol ether).

– Pre-cleaning (mechanical) removes solid foreign items using centrifuges and pressure sorters.

– Refining provides washing, sorting and milling of the pulp.– Final cleaning (mechanical) to remove items released in the refining step.– Thickening reducing the water content and allowing for storing.– Drying


Paper Recycling 1: Major Grades

• There are about 80 grades of fiber• Major grades:

1. Pulp substitutes• Unprinted trimmings from envelopes and high grade paper• Generated in paper mills only• Primarily reused in tissue, also in book stock


Paper Recycling 2: Major Grades

Post Consumer2. High grade deinking

Office white paper3. Old corrugated (OCC) 4. Old newsprint (ONP)


Paper Recycling 3 – Major Grades

5. Residential mixed paper (RMP)office waste, third class mail, boxboard (cereal boxes), magazines, telephone books, OCC, coated packaging

6. Mixed office paper7. OMG - old magazines8. OTP - old telephone books


Paper Recycling 4: ONP

• ~4% of MSW in 2010 (includes 18.8% advertising)• ~70% recovery rate• Uses:

– largest use is in new newsprint– recycled paperboard– cereal & shoe boxes, tablet backs– cellulose insulation, roofing felt– animal bedding– export


Paper Recycling 5: ONP

• Specifications – #6 news - <1% prohibited material– #8 news - 0.25% prohibited material, bought by mills

• Dec., 2012 Prices– #6 – 50 $/ton– #8 – 90 $/ton


Cardbox Composition

• Linerboard - The inside and outside of a box that confers strength • Medium(fluting) - fluted section in between linerboard• Containerboard – a box


Paper Recycling 6: OCC

• ~12% of MSW (2001)• ~71% recovery rate• Uses:

– Container board (linerboard and corrugating medium)• news boxes require 20% OCC• construction products• wallboard, roofing felt• Paperboard

• Dec. 2012 Prices – 70-130 $/ton


Paper Recycling 7: OFF

• There are a number of grades of office paper:– office paper only– white copy and pad paper– standard office mix that may include:

• envelopes (with and without plastic)• mail including coated papers• colored paper• folders and card stock


Paper Recycling 8: Office Paper (OFF)

• ISRI Grades & 2006 Price: – 127: sorted white ledger – 119: sorted color ledger – Mixed Office Paper

• “Clean, sorted ledger & writing papers, free of brown grades, cardboard, boxboard, may contain up to 10% groundwood paper fiber content”


Paper Recycling 9: Office Paper (OFF)

• Problems– no consistent definitions/varying markets– adhesive labels, stamps– paper clips, plastics– grey and brown products (brightness)

• Uses:– historically tissue paper– printing and white (somewhat grey) paper is a newer use– Federal agencies must use paper with 30% recycled content by

1998


Paper Recycling 10: Old Magazines (OMG)

• Coated magazine and catalog papers• OMG facilitates ONP ink flotation• Ample market capacity given high demand for ONP


Paper Recycling 11: Residential Mixed Paper (RMP)

• May contain OMG, books, ONP, third class mail, envelopes,food cartons and OCC

• A relatively low quality fiber but incentives to use:– cheap and in large supply

• Uses are limited due to fiber length:– Egg cartons, roofing felt, fruit, separators– Boxboard and wallboard backing


Paper Recycling 12: RMP

• May be used where shortages of other paper grades develop• Price will depend on availability of better papers • Solid waste manager must figure out what to separate and what to

leave as mixed paper– Flexibility is key


Paper Recycling 13

• Effects of recycling– weaker fibers– decreased burst strength– stiffer paper

This decreases ability to light weight a box• Losses During Recycling:

– OCC: 10-15%– OMG: 40-60%– OFF: 8-20%


Paper Recycling 14: European paper flows

Ref: CEPI, 2004

Million tonnes


Paper Recycling 15: Paper market prices

Ref: Danfiber, 2009


Container Glass: Short version

• Glass is made primarily from sand (quartz), soda and lime; none-renewable but not scarce resources

• Problems with post-consumer glass: Mix of colors, foreign objects (ceramics, metal caps). More than a few percent of wrong color affects the color of the remanufactured product

• Major benefits: Energy savings in production• Products: Glass containers/bottles, insulation material


Glass: Types

• Soda-lime glass, which is used for bottles, jars, drinking glasses and window glass, is typically produced from 70-75% quartz sand (SiO2, particle size 0.1-0.4 mm), 12-16% soda (Na2O, Na2CO3), 10-15% lime (CaO, CaCO3) and traces of other materials.

• Crystal glass, which is used for high-quality drinking glasses, vases, art etc, is typically produced from 54-65% SiO2, 18-38% PbO, 13-15% Na2O or K2O and various other oxides.

• Borosilicate glass (Pyrex glass), which is used for laboratory glass ware, kitchen glass ware and high temperature lamps, is typically produced from 70-78% SiO2, 7-13% B2O3, 4-8% Na2O and K2O, and 2-7% Al2O3. Borosilicate glass is corrosion and temperature resistant.


Container Glass Recycling 1

• Glass is about 5.5% of MSW / 90% containers – beer and soda– food jars– wine/liquor– ~55% clear (flint)– ~6% green (50% imported)– ~38% brown (amber)

• Only container glass can be recycled



• Recycling processing– Color separation is critical due to tight specs on end product

(glass containers)• optical sorting possible at regional level

• Source separation is most efficient as breakage reduces ability to separate colors



Pricing ($/ton) – Dec. 2009end user

Clear 29Brown 17Green 8

Market for recycled glass historically stable (except green) market share is shrinking due to plastic



Uses• new beverage containers • these alternates provide a market for mixed color glass

– substitute for stone and sand in asphalt (up to 20%)– fiberglass insulation– drainage material

• 1992: California required fiberglass manufacturers to use 30% recycled glass



Processing• Shipped either crushed or loose• Cullet (crushed glass) requires less energy to melt compared to

sand & already contains additivesSpecifications• clear - 95%, green and brown - 90%• no metal, rocks, ceramic


Aluminum: Short version

• Aluminum is obtained under great energy expenses from mined bauxite, a limited non-renewable mineral

• Problems with post-consumer aluminum: Few if clean from other metals

• Major benefits: Energy savings in production, preserving a resource with a large “environmental signature”

• Products: Any new aluminum product. No loss of quality


Aluminum Recycling

• Al is about 0.7% of MSW• The aluminum stream contains:

– ~63% Beverage containers– ~14% Other non-durables

• Foil & other packaging– ~23% Durables

• Appliances, lawn furniture, construction waste (gutters, etc.)


Aluminum Recycling

What can be recycled? Essentially everything - the only limit is cleanliness and price

paid Price structure (Dec. 2012):

delivered to end userUBC - Used beverage can 1200-1800 $/tonClean scrap higherFoil lower


Market Conditions

• The aluminum companies will buy as much as they can get• Recycled aluminum is used for:

– New beverage cans - 27%– Building and construction - 21%– Transportation - 21%– Electrical goods - 9%– Other - 23%

• Major barrier to aluminum recycling is collection• National UBC recovery rate is <50% (2007), Higher (70 - 95%) in

states with bottles bills


Aluminum Recycling

• Processing of used aluminum– Shred, flatten or bail for transport, cans are actually blown into a

trailer• Tremendous energy savings realized with use of recycled

aluminum– ~95% energy saving in production– Eliminates energy for mining– Requires energy for collection


Iron / steel: Short version

• Iron / steel is obtained under great energy expenses from mined ore. Iron is a non-renewable mineral, but rather abundant

• Problems with post-consumer : Few if clean from other metals (tin as plating, lead as solder)

• Major benefits: Energy savings in production, preserving a resource with a large “environmental signature”

• Products: Any new iron product. If tin or lead have penetrated into the iron, the quality may be lower


Steel Recycling

• 7.9% of solid waste stream• 22% of steel is food and beverage cans• 58% -appliance, furniture, tires, other durables (excludes - cars,

construction waste)• Ferrous metal is easily separated from shredded MSW with

magnets but this is quite rare (~95% pure)


Steel Recycling• Depending upon the furnace type - can utilize 20 to 100% scrap as

raw material• Market is soft and fluctuates but overall market capacity is adequate

– Controlled by price at scrap yard– White goods - dealers may charge if they contain CFCs

• Pricing (Dec. 2012)Cans 100-200 $/ton

Ref: Danfiber, H.J. Hansen, Westmetall, 2009


Plastics Recycling

• ~12% of MSW stream by weight• Plastics - polymers that can be formed into shapes, typically by the

application of heat and/or pressure• Two categories

– thermoplastics: soften when heated and can be remolded (recycled)

• 85% of manufactured plastic– thermosetting: do not soften when heated and cannot be

remolded, limited opportunity for recycling• 15% of manufactured plastic


Plastics Production

• Raw materials:– ethylene oxide, benzene– Raw materials ---> resin (petrochemical industry) ~300– Resin ----> molded products (independent producers) 1000's– hundreds of types of resins


Plastic Recycling

• Plastics can only be recycled if separated by resin type• Currently no mechanical processes are available to sort plastic from

mixed refuse• Sortation of HDPE/PET/PVC can be done


Types Of Thermoplastics: HDPE

High density polyethylene (HDPE)• Consumer products:

– Containers for milk, water, foods, oil (~0.3% of MSW)• Major division for recycling:

– translucent HDPE - milk and water jugs (0.05 – 0.30 $/lb baled)– pigmented HDPE - household industrial chemical containers

(HICs) (0.13 – 0.22 $/lb):– oil, detergent, shampoo


Types Of Thermoplastics: HDPE

• Recycle market: – Need for translucent/pigment separation is not always

necessary– some MRFS ship mixed PET/HDPE (lower value)

• Products:– Garbage bags, flower pots, speed bumps, drain pipes, auto

parts, films, toys, – Sandwich layer in bottles


Types Of Thermoplastics: PET

Polyethylene terephthalate (PET)• Consumer products: soda and liquor bottles

– beverage bottles - ~0.4% of MSW– custom PET is other recyclable component

• Major recycled markets: – carpets, polyester fiberfill, auto parts, textiles (~70%)– approved for contact with food (1998)

44Copyright Anders Damgaard & Morton A. Barlaz, NC State University44

Types Of Thermoplastics: PET The most widely recycled resin because 30% of the U.S.

population lives in bottle bill states Also the most valuable plastic resin

ethylene glycol plus dimethyl terephthalate


Types Of Thermoplastics: Polystyrene (PS) (Styrofoam)

• Consumer products:– Fast food packaging, packing for shock insulation, eating

utensils, dairy containers• Recycled markets:

– Packing for shock insulation, desk accessories• Recycling:

– Technically feasible• Limitations:

– cost due to light weight– cost to wash


Types Of Thermoplastics: PVC

• Polyvinyl chloride (PVC)– has been a shift away from use in household containers– it burns before PET melts

• Polypropylene (PP)– Films, Textiles


Composition of Plastic Waste Stream (2005) (See Table 7 for 2010 data)

Resin Type Durables % Non- Durables %PET 5.5 3.7HDPE 7.5 10.8PVC 5.9 10.0LDPE/LLDPE 8.8 37.0PP 15.7 13.7PS 8.4 23.0Other 48.2 1.5


Products for which the majority is made from one resin

Item Resin/ Share of Product Food Packaging Film LDPE/ 65%Carryout bags HDPE/ 63%Dairy containers HDPE/52%Pipe and conduit PVC/ 96%Trash bags LLDPE/ 62%HIC bottles HDPE/ 80%LLDPE - Linear Low Density Polyethylene


Plastic Recycling

• What left must be treated as commingled plastic– it can be made into plastic lumber– development of construction specifications – expensive relative to wood for all but high end uses, need

specific uses– new life as CCA treated lumber is banned

• Other sources of pure material:– pallet wrap– process trimmings

50Copyright Anders Damgaard & Morton A. Barlaz, NC State University50

Barriers To Recycling

1 Collection/participation2 Cost of resin fluctuates


Wood Waste• Pallets, tree trimmings, land clearing debris• Typically comes in ”Monoloads" • Markets BioCycle,Jan., 1995: $/ton

– Paper pulp 2-5– Wood composite materials 5-35– Fuel (8500 BTU/lb) 0-20– Mulch 0-10– Landfill cover 0-2– Road stabilization ?– animal bedding 0-20

The distance to market is critical as the value is low: transportation cost - 0.1 $/ton-mi


Tire Recycling

• Generation rate ~ 1 per person per year– 290 million generated in 2003– Proper inflation = source reduction!!

• Unique problems– Whole tires do not stay buried in landfills– Serve as breeding grounds for mosquitoes– Present a special fire hazard


Tire Recycling

• Alternative uses for tires– Retreading– Direct reuse– combustion – tire derived fuel (TDF) – Reuse in other products


Tire Recycling

• A tire contains three components:– Rubber (~12 lb)– Fabric (~4 lb)– Metal (~4 lb)

• In several layers:– Rubber– Beads– Fabric and steel– Rubber / tread


Tire Recycling

• Combustion– As "tire derived fuel" in industrial boilers (~50% of all tires)

• Cement kilns where the lime in cement neutralizes the SO2• Whole or 2" chips• Paper industry boilers

– 2" chips• Utilities -- ?

http://www.rma.org/scrap_tires/


Tire Recycling

• Reuse in other products– Drainage material – CE Applications (14.2% in 2001)

• leachate distribution• septic fields• erosion control• subgrade fill• backfill for walls and bridge abutments


Tire Recycling

• Crumb rubber for low end rubber products (11.7% in 2001)– car mats– mud flaps– shoe soles– carpet backing– tires for wheel barrel and tricycles– recreational surfaces (e.g. tennis courts)

58Copyright Anders Damgaard & Morton A. Barlaz, NC State UniversityCopyright Morton A. Barlaz, NC State University 58

Low end rubber products (contd.) Overall demand is not adequate Over 50% of U.S. demand for rubber is for tires Any time crumb rubber is produced, steel and fiber remain

for disposalUse in asphalt rubber mixtures

Technically feasible but typically not as viable as combustion

Tire Recycling


Tire Recycling

SUMMARY1. Use in cement kilns, and use in other boilers as TDF works well

and is dominant outlet2. Demand for use as a drainage material varies with location


Material Markets• Prices are volatile

BLS OCC National

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Overview of Futures Markets


Material Specifications

• Often subjective but reputation is critical• MRFs and processors must have end users (purchasers)

– Often will take less money for sales guarantees• Specifications vary

– with the plant capability– with material demand over time

03 matl recycle - ncsu coe people matl recycle.pdf · • manufacturing is cheaper (energy,...

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