overview of current activities in industrial by-products ... · overview of current activities in...

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Center for By-Products Utilization

Overview of Current Activities in Industrial By-Products and Post-Consumer Waste Recycling and

Utilizationby

Tarun R. NaikResearch Professor and Director, UWM Center for By-Products Utilization

University of Wisconsin – Milwaukee

and Rudolph N. Kraus

Assistant Director, UWM Center for By-Products UtilizationUniversity of Wisconsin – Milwaukee

Presented at the MSOE Master of Science in Environmental EngineePresented at the MSOE Master of Science in Environmental Enginee ring Symposium, “Exploring ring Symposium, “Exploring Synergies in Materials Management,” January 30, 2008, Milwaukee,Synergies in Materials Management,” January 30, 2008, Milwaukee, WI WI


UWM Center for By-Products Utilization

• Authorized by UWM in September 1988

• Began Operation in January 1989

• Tarun R. Naik, Director of UWM-CBU

• Rudi Kraus, Assistant Director

• Yoon-moon Chun, Post-Doctoral Research Associate


UWM-CBU’s Mission• Perform Research and Develop Practical

Information for Beneficial Recycling from Industrial, Commercial, and Private Sectors– Working with Industry, Government Agencies,

Engineering Committees, and Others– Teaching and Training Students in Recycling

Technologies– Technology Transfer Activities

• Over 65 Workshops and Symposiums – More that 2,000 Attendees

• Research Reports, Papers, and Technical Presentations at Conferences

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Basic ApproachBasic Approach

WA$TE is wasted if you waste it, WA$TE is wasted if you waste it, otherwise it is a resource. Resource is otherwise it is a resource. Resource is

wasted if you ignore it and do not wasted if you ignore it and do not conserve it with holistic best practices and conserve it with holistic best practices and reduce societal costs. Resource is for the reduce societal costs. Resource is for the

transformation of people and society. transformation of people and society.


Disposal in LandfillsDisposal in Landfills

• Cost (transportation, fees, and taxes)

• Decreasing landfill space

• Unknown future liabilities


By-Product Experience

• Coal Combustion By-Products– Fly Ash, Bottom Ash, Slag, FGD Materials

• Wood Ash• Blended Ash (Blends of Coals, Wood/Coal Ash)

• Used Foundry Sand, Slag, Bag-House Dust• Pulp and Paper Mill Residual Solids• Limestone Quarry Fines (Dust and Crusher Fines)

• Lumber Industry Waste (Wood, Sawdust)

• Dredged Materials• Post-Consumer Waste

– Plastics, Used Tires, Glass Cullet, Gypsum Drywall

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Coal Combustion Products

- Fly ash

- Bottom ash


The precise properties of CCPsare dependent upon the kind of coal each utility burns and the type of boiler used. Coal mined in the western United States, for example, produces fly ash that has more lime and less silica than ash from eastern coal.


Of all the uses for fly ash, the best known are as an additive in portland cement (or, directly in concrete as a SCM) and as a raw-feed material in the production of portland cement.

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Portland Cement + Water

Cementitious Material

Fly Ash/Pozzolan

Free Lime/Ca(OH2)

+


Benefits of Fly Ash in Concrete

-Increased Strength-Reduced Shrinkage-Reduced Permeability-Improved Durability-Increased Abrasion Resistance


Current Uses–Concrete–Cement Raw-feed–Bricks, blocks, and paving stones

–Flowable Slurry and/or SCC–Blended Cements–Aggregates from bottom ash and/or slag

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Foundry Sand

Mined foundry sands are silica sand of graded size used for making molds.

Sand molds are made to cast a hollow shape in which molten metal is poured to cast a metal product. Sand in the

mold is bonded by clay (green sand) or chemicals (clay-bonded or chemically-

bonded).


Foundry Sand (cont’d)

Used foundry sand from green-sand molds are black in color, due to the carbon content. It is finer than typical concrete sand due to

the presence of clay.

Chemically-bonded sands are lighter in color and coarser than green sands.


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Large-Volume Recycling Options for Used Foundry

Sand- Portland cement concrete

- Raw-feed for cement production

- Asphaltic concrete- Bricks, blocks, and paving stones - Flowable slurry or CLSM (Controlled

low strength materials)



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Wood Fly Ash

Generated by burning a combination

of wood products and coal, coke, or

oil for the pulp and paper industry,

and wood-products industry.


1000X Magnification

100X Magnification


Wood Ash Use Opportunities• Flowable Fill Materials• Structural-Grade Concrete

• Bricks, Blocks, and Paving Stones• Decorative Aggregate & Roofing Shingle

Grit• Roller Compacted Concrete Pavement• Self-Consolidating Concrete• Soil Amendment• Blended Cements

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Pulp and Paper Mills and Paper-recycling Facilities Residual Solids (i. e., sludge)

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Pulp Mill Primary Sludge Solids


100X Magnification 1000X Magnification

BR


Residual Fiber Reinforcing a Micro-crack in Concrete

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Reasons for Fiber Reinforcement of Concrete

• Inherently, concrete is a brittle material.

• By incorporating fibers into concrete, its toughness and tensile strength can be improved; and, also, shrinkage cracking can be reduced.


Fly ash slurry (without fibrous residuals)


Water, fibrous residuals, cement, and fly ash in the mixer

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POST-CONSUMER GLASS

• Approximately 200 thousand tons of post-consumer glass is produced each year in Wisconsin; and, about 12 million tons is produced in USA.

• Only about 1/4 of glass is being recycled due to co-mingling of colors.

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POST-CONSUMER GLASS

§US annual production: 35 billion glass containers.§20% of glass is recycled to produce new

bottles (2.4 million tons); and, about 5% 0.6 million tons) is used for miscellaneous uses.§The rest is landfilled (1.3% of all solid

wastes, about nine million tons)



Possible Options for Post-consumer Glass Use in Construction

• In asphalt paving mixture as a substitute for fine aggregate

• Flowable slurry (CLSM)

• Concrete masonry products

• Structural concrete

• Sub-base course materials

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Post-consumer Glass in Structural Concrete

• Silica present in the post-consumer glass may react with alkali of cement causing detrimental expansive alkali silica reaction (ASR).

• Glass can be used in concrete along with a suitable suppresser of ASR expansion; e. g. Class F fly ash.


USE OF POST-CONSUMER PLASTICS IN CEMENT-BASED COMPOSITES

• Approximately 20 million tons of post-consumer plastics is generated in the USA.

• Although post-consumer plastics constitutes over 8 % of total municipal solid waste by weight, they constitute nearly 20 % of the total municipal wastes by volume.

• Less than 2.5 % of the total post-consumer plastics is recycled/reused.

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• A need exists to find high-volume uses of post-consumer plastics, especially in cementitious matrix composites that may consume a large amounts of the post-consumer plastics generated (even possibly all of the post-consumer plastics).

• Cement-based materials are inherently brittle in nature. Plastics with high-tensile strength should help improve the the tensile & flexural strengths, fatigue strength, as well as fracture toughness.


• Increased ductility in concrete can be introduced through addition of more ductile materials, such as post-consumer plastics.

• Ductility in a material is characterized by high-tensile strain capability before fracture.

• Research conducted at the UWM Center for By-Products Utilization included finding best uses of post-consumer plastics in concrete and other concrete-making materials.


Summary

• UWM-CBU Research, education, and demonstration projects show that there are options to disposal of by-products

• Recycled materials are not waste!• Using recycled materials should be a first

option in engineering design• Think sustainability! • Promote recycled materials and commit

to make it happen

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THANK YOU

For your interest

More information at<www.cbu.uwm.edu>

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