TecEco EcoCement Concretes Abatement, Sequestration and Waste Utilization in the Built Environment

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TecEco Eco-Cement Concretes Abatement,
Sequestration and Waste Utilization in the Built
Environment
If we can make materials that take less than half
as much energy, last more than twice as long (are
more durable) and have a use when they are
retired as well as make them net carbon sinks
Then these materials must be sustainable.
Our slides are deliberately verbose as most
people download and view them from the net.
Because of time constraints I will have to race
over some slides John Harrison B.Sc. B.Ec.
FCPA.
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TecEco Binder Systems
SUSTAINABILITY
PORTLAND
POZZOLAN
Hydration of the various components of Portland
cement for strength.
Reaction of alkali with pozzolans (e.g. lime with
fly ash.) for sustainability, durability and
strength.
TECECO CEMENTS
DURABILITY
STRENGTH
TecEco concretes are a system of blending
reactive magnesia, Portland cement and usually a
pozzolan with other materials and are a key
factor for sustainability.
REACTIVE MAGNESIA
Hydration of magnesia gt brucite for strength,
workability, dimensional stability and
durability. In Eco-cements carbonation of brucite
gt nesquehonite, lansfordite and an amorphous
phase for sustainability.
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TecEco Formulations

• Tec-cements (5-15 MgO, 85-95 OPC)
• contain more Portland cement than reactive
  magnesia. Reactive magnesia hydrates in the same
  rate order as Portland cement forming Brucite
  which uses up water reducing the voidspaste
  ratio, increasing density and possibly raising
  the short term pH.
• Reactions with pozzolans are more affective.
  After all the Portlandite has been consumed
  Brucite controls the long term pH which is lower
  and due to its low solubility, mobility and
  reactivity results in greater durability.
• Other benefits include improvements in density,
  strength and rheology, reduced permeability and
  shrinkage and the use of a wider range of
  aggregates many of which are potentially wastes
  without reaction problems.
• Eco-cements (15-95 MgO, 85-5 OPC)
• contain more reactive magnesia than in
  tec-cements. Brucite in porous materials
  carbonates forming stronger fibrous mineral
  carbonates and therefore presenting huge
  opportunities for waste utilisation and
  sequestration.
• Enviro-cements (5-15 MgO, 85-95 OPC)
• contain similar ratios of MgO and OPC to
  eco-cements but in non porous concretes brucite
  does not carbonate readily.
• Higher proportions of magnesia are most suited to
  toxic and hazardous waste immobilisation and when
  durability is required. Strength is not developed
  quickly nor to the same extent.

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The Magnesium Thermodynamic Cycle
Calcination
CO2 CaptureNon fossil fuel energy
We think this cycle is relatively independent of
other constituents
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Strength with Blend Porosity
Tec-cement concretes
Eco-cement concretes
High Porosity
Enviro-cement concretes
High OPC
High Magnesia
STRENGTH ON ARBITARY SCALE 1-100
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The Carbon Cycle and Emissions
The cause of the global warming problem
Source David Schimel and Lisa Dilling, National
Centre for Atmospheric Research 2003
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Abatement and Sequestration

• To solve the greenhouse gas problem our approach
  should be holistically balanced and involve
• Everybody, every day
• Be easy
• Make money

New technical paradigms are required
Sequestration
Abatement
and


TecEco-cements Low Emissions
ProductionMineral Sequestration Waste
utilization
Emissions reductionthrough efficiency
andconversion to non fossil fuels
Geological Seques-tration
TecEcos Contribution
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Ramifications of TecEco Eco-Cement Technologies

• CO2 is a waste
• We need to think about supply and waste impacts
  when we design materials not just about the
  utility phase in the middle.
• Making the built environment a repository for
  waste and huge carbon sink as proposed by TecEco
  is a politically viable and economic alternative.
• Concrete, a cementitous composite, is the single
  biggest material flow on the planet with over 2
  tonnes per person produced and a good place to
  start.
• By including carbon, materialsare potentially
  carbon sinks.
• By including wastes many problems at the waste
  end are solved.

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TecEco Technologies Provide a Profitable Solution

• Silicate ? Carbonate Mineral Sequestration
• Using either peridotite, forsterite or serpentine
  as inputs to a silicate reactor process CO2 is
  sequestered and magnesite produced.
• Proven by others (NETL,MIT,TNO, Finnish govt.
  etc.)
• Tec-Kiln Technology
• Combined calcining and grinding in a closed
  system allowing the capture of CO2. Powered by
  waste heat, solar or solar derived energy.
• To be proved but simple and should work!
• Direct Scrubbing of CO2 using MgO
• Being proven by others (NETL,MIT,TNO, Finnish
  govt. etc.)
• Tec and Eco-Cement Concretes in the Built
  Environment.
• TecEco eco-cements set by absorbing CO2 and are
  as good as proven.

TecEco
More EconomicunderKyoto?
TecEco
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The TecEco Total Process
Olivine Mg2SiO4
This reaction is how most MgCO3 came to be formed
anyway so why are we not using it to also
sequester carbon?
Serpentine Mg3Si2O5(OH)4
Crushing
Crushing
CO2 from Power Generation or Industry
Grinding
Grinding
Waste Sulfuric Acid or Alkali?
Screening
Screening
Silicate Reactor Process e.g. Mg2SiO4 2CO2
gt2MgCO3 SiO2
Magnetic Sep.
Gravity Concentration
Heat Treatment
Fe, Ni, Co.
Magnesite (MgCO3)
Silicic Acids or Silica
Non Stored Energy Powered Tec-Kiln
CO2 for Geological Sequestration
Magnesium Thermodynamic Cycle
Magnesite MgCO3)
Magnesia (MgO)
Oxide Reactor Process
Other Wastes after Processing
CO2 from Power Generation, Industry or CO2
Directly From the Air
MgO for TecEco Cements and Sequestration by
Eco-Cements in the Built Environment
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The TecEco Dream A More Sustainable Built
Environment
CO2
OTHERWASTES
CO2 FOR GEOLOGICAL SEQUESTRATION
PERMANENT SEQUESTRATION WASTE UTILISATION (Man
made carbonate rock incorporating wastes as a
building material)
MINING
MgO
TECECO KILN
MAGNESITE OTHER INPUTS
TECECO CONCRETES
RECYCLED BUILDING MATERIALS
We need materials that require less energy to
make them, that last much longer and that
contribute properties that reduce lifetime
energies
There is a way to make our city streets as green
as the Amazon rainforest. Fred Pearce, New
Scientist Magazine
SUSTAINABLE CITIES
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TecEco Kiln Technology

• Grinds and calcines at the same time.
• Runs 25 to 30 more efficiency.
• Can be powered by variable non fossil fuel
  energy.
• Theoretically capable of producing much more
  reactive MgO
• Even with ores of high Fe content.

• Captures CO2 for bottling and sale to the oil
  industry (geological sequestration).
• Runs at low temperatures.
• Can be run cyclicly as part of a major process to
  solve global CO2 problems.
• Will result in new markets for ultra reactive low
  lattice energy MgO (e.g. paper and environment
  industries)
• TecEco need your backing to develop the kiln

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Advantages of Adopting TecEco Eco-Cement
Technology

• Utilizing wastes to make materials like
  concretes.
• Tec-cements have more rapid strength development
  with fly ash, bottom ash, industrial slags etc.
  (Tec-Cements.)
• Reducing energy and emissions during the
  production of cements using the TecEco kiln.
• MgO can be made using non fossil fuel energy
• Concretes containing MgO are demonstrably more
  durable.
• It makes sense to sequester carbon by allowing
  MgO to re-carbonate and thereby gain strength.

The biggest business on the planet is going to be
the sustainability business
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TecEco Technologies Take Concrete into the Future

• More rapid strength gain even with added
  pozzolans
• More supplementary materials can be used reducing
  costs and take and waste impacts.
• Higher strength/binder ratio
• Less cement can be used reducing costs and take
  and waste impacts
• More durable concretes
• Reducing costs and take and waste impacts.
• Use of wastes
• Utilizing carbon dioxide
• Magnesia component can be made using non fossil
  fuel energy and CO2 captured during production.

Tec -Cements
Tec Eco-Cements
Eco-Cements
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Carbonation

• Eco-cement is based on blending reactive
  magnesium oxide with other hydraulic cements and
  then allowing the Brucite and Portlandite
  components to carbonate in porous materials such
  as concretes blocks and mortars.
• Magnesium is a small lightweight atom and the
  carbonates that form contain proportionally a lot
  of CO2 and water and are stronger because of
  superior microstructure.
• The use of eco-cements for block manufacture,
  particularly in conjunction with the kiln also
  invented by TecEco (The Tec-Kiln) would result in
  sequestration on a massive scale.
• As Fred Pearce reported in New Scientist Magazine
  (Pearce, F., 2002), There is a way to make our
  city streets as green as the Amazon rainforest.

Ancient and modern carbonating lime mortars are
based on this principle
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Eco-Cement Biomimicry

• During earth's geological history large tonnages
  of carbon were put away as limestone and other
  carbonates and as coal and petroleum by the
  activity of plants and animals.
• Sequestering carbon in magnesium binders and
  aggregates in the built environment mimics nature
  in that carbon is used in the homes or skeletal
  structures of most plants and animals.

In eco-cement blocks and mortars the binder is
carbonate and the aggregates are preferably wastes
We all use carbon and wastes to make our homes!
Biomimicry
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A Post Carbon Age
We cannot get there without new technical
paradigms. The construction industry can be
uniquely responsible for helping achieve this
transition

• By enabling us to make productive use of
  particular raw materials, technology determines
  what constitutes a physical resource1
• Pilzer, Paul Zane, Unlimited Wealth, The Theory
  and Practice of Economic Alchemy, Crown
  Publishers Inc. New York.1990

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Why Magnesium Carbonates?

• Because of the low molecular weight of magnesium,
  magnesium oxide which hydrates to magnesium
  hydroxide and then carbonates, is ideal for
  scrubbing CO2 out of the air and sequestering the
  gas into the built environment
• More CO2 is captured than in calcium systems as
  the calculations below show.
• At 2.09 of the crust magnesium is the 8th most
  abundant element
• Magnesium minerals are potential low cost. New
  kiln technology from TecEco will enable easy low
  cost simple non fossil fuel calcination with CO2
  capture of magnesium carbonate.

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Why Magnesium Carbonates?

• Reactive, low lattice energy forms of magnesium
  oxide are most suitable as they are
• Easier to get into solution
• Efficiently absorb CO2
• A high proportion of CO2 and water means that a
  little MgO goes a long way.
• In terms of sequestration or binder produced for
  starting material in cement, eco-cements are much
  more efficient.
• Capture of CO2 during manufacture and use for
  sequestration directly in the built environment
  makes a lot of sense.

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Drivers for TecEco Cement and Kiln Technology
Government Influence Carbon Taxes Provision of
Research Funds Environmental education
TecEco kiln technology could be the first non
fossil fuel powered industrial process
Consumer Pull Environmental sentimentFear of
climate changeCost and technical
advantagesCompetition, robotics
Huge Markets Cement 2 billion tonnes. Bricks
130,000 million tonnes
Producer Push The opportunity cost of compliant
waste disposal Profitability and cost
recovery Technical merit Resource
issues Robotics Research objectives
TecEco cements are the only binders capable of
utilizing very large quantities of wastes based
on physical property rather than chemical
composition overcoming significant global
disposal problems, and reducing the impact of
landfill taxes. TecEco eco-cements can sequester
CO2 on a large scale and will therefore provide
carbon accounting advantages.
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Eco-Cements

• Eco-cements are similar but potentially superior
  to lime mortars because
• The calcination phase of the magnesium
  thermodynamic cycle takes place at a much lower
  temperature and is therefore more efficient.
• Magnesium minerals are generally more fibrous and
  acicular than calcium minerals and hence add
  microstructural strength.
• Water forms part of the binder minerals that
  forming making the cement component go further.
  In terms of binder produced for starting material
  in cement, eco-cements are much more efficient.
• Magnesium hydroxide in particular and to some
  extent the carbonates are less reactive and
  mobile and thus much more durable.

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Eco-Cement Strength Development

• Eco-cements gain early strength from the
  hydration of PC.
• Later strength comes from the carbonation of
  brucite forming an amorphous phase, lansfordite
  and nesquehonite.
• Strength gain in eco-cements is mainly
  microstructural because of
• More ideal particle packing (Brucite particles at
  4-5 micron are under half the size of cement
  grains.)
• The natural fibrous and acicular shape of
  magnesium carbonate minerals which tend to lock
  together.
• More binder is formed than with calcium
• Total volumetric expansion from magnesium oxide
  to lansfordite is for example volume 811.

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Eco-Cement Strength Gain Curve
Eco-cement bricks, blocks, pavers and mortars
etc. take a while to come to the same or greater
strength than OPC formulations but are stronger
than lime based formulations.
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Chemistry of Eco-Cements

• There are a number of carbonates of magnesium.
  The main ones appear to be an amorphous phase,
  lansfordite and nesquehonite.
• The carbonation of magnesium hydroxide does not
  proceed as readily as that of calcium hydroxide.
• ?Gor Brucite to nesquehonite - 38.73 kJ.mol-1
• Compare to ?Gor Portlandite to calcite -64.62
  kJ.mol-1
• The dehydration of nesquehonite to form magnesite
  is not favoured by simple thermodynamics but may
  occur in the long term under the right
  conditions.
• ?Gor nesquehonite to magnesite 8.56 kJ.mol-1
• But kinetically driven by desiccation during
  drying.
• Reactive magnesia can carbonate in dry conditions
  so keep bags sealed!
• For a full discussion of the thermodynamics see
  our technical documents.

TecEco technical documents on the web cover the
important aspects of carbonation.
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Eco-Cement Reactions
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Eco-Cement Micro-Structural Strength
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Proof of Carbonation - Minerals Present After 18
Months
XRD showing carbonates and other minerals before
removal of carbonates with HCl in a simple Mix
(70 Kg PC, 70 Kg MgO, colouring oxide .5Kg, sand
unwashed 1105 Kg)
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Proof of Carbonation - Minerals Present After 18
Months and Acid Leaching
XRD Showing minerals remaining after their
removal with HCl in a simple mix (70 Kg PC, 70 Kg
MgO, colouring oxide .5Kg, sand unwashed 1105 Kg)
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CO2 Abatement in Eco-Cements
No Capture11.25 mass reactive magnesia, 3.75
mass Portland cement, 85 mass
aggregate. Emissions.37 tonnes to the tonne.
After carbonation. approximately .241 tonne to
the tonne.
Portland Cements15 mass Portland cement, 85
mass aggregate Emissions.32 tonnes to the
tonne. After carbonation. Approximately .299
tonne to the tonne.
Capture CO211.25 mass reactive magnesia, 3.75
mass Portland cement, 85 mass
aggregate. Emissions.25 tonnes to the tonne.
After carbonation. approximately .140 tonne to
the tonne.
Capture CO2. Fly and Bottom Ash11.25 mass
reactive magnesia, 3.75 mass Portland cement, 85
mass aggregate. Emissions.126 tonnes to the
tonne. After carbonation. Approximately .113
tonne to the tonne.
For 85 wt Aggregates 15 wt Cement
Eco-cements in porous products absorb carbon
dioxide from the atmosphere. Brucite carbonates
forming lansfordite, nesquehonite and an
amorphous phase, completing the thermodynamic
cycle.
Greater Sustainability
.299 gt .241 gt.140 gt.113Bricks, blocks, pavers,
mortars and pavement made using eco-cement, fly
and bottom ash (with capture of CO2 during
manufacture of reactive magnesia) have 2.65 times
less emissions than if they were made with
Portland cement.
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Aggregate Requirements for Carbonation

• The requirements for totally hydraulic limes and
  all hydraulic concretes is to minimise the amount
  of water for hydraulic strength and maximise
  compaction and for this purpose aggregates that
  require grading and relatively fine rounded sands
  to minimise voids are required
• For carbonating eco-cements and lime mortars on
  the on the hand the matrix must breathe i.e.
  they must be porous
• requiring a coarse fraction to cause physical air
  voids and some vapour permeability.
• Coarse fractions are required in the aggregates
  used!

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Roman Specifications

• The oldest record Book II, chapter IV of the Ten
  Books of Architecture by Vitruvius Pollio.
• According to Vitruvius the best (sand) will be
  found to be that which crackles when rubbed in
  the hand, while that which has much dirt in it
  will not be sharp enough. Again throw some sand
  upon a white garment and then shake it out if
  the garment is not soiled and no dirt adheres to
  it, the sand is suitable Vitruvious was talking
  about gritty sand with no fines.
• The 16th century architect Andrea Palladio is
  renowned for "The Four Books of Architecture
• translated into English in the early 18th century
• used as a principal reference for building for
  almost two centuries (Palladio, Isaac Ware
  translation, 1738).
• In the first book Palladio says, "the best river
  sand is that which is found in rapid streams, and
  under water-falls, because it is most purged". In
  other words, it is coarse. Compare this with most
  sand for use in mortar today.
• The conclusion form history is that a coarse
  gritty sand that is not graded for minimum paste
  is required.

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Using Wastes and Non-Traditional Aggregates to
Make TecEco Cement Concretes

• As the price of fuel rises, theuse of on site
  low embodiedenergy materials ratherthan carted
  aggregates willhave to be considered.

No longer an option?
Recent natural disasters such as the recent
tsunami and Pakistani earthquake mean we urgently
need to commercialize TecEco technologies because
they provide benign environments allowing the use
of many local materials and wastes without
delayed reactions
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Using Wastes and Non-Traditional Aggregates to
Make TecEco Cement Concretes

• Many wastes and local materials can contribute
  physical property values.
• Plastics for example are collectively light in
  weight, have tensile strength and low
  conductance.
• Tec, eco and enviro-cements will allow a wide
  range of wastes and non-traditional aggregates
  such as local materials to be used.
• Tec, enviro and eco-cements are benign binders
  that are
• low alkali reducing reaction problems with
  organic materials.
• stick well to most included wastes
• Tec, enviro and eco-cements can utilize wastes
  including carbon to increase sequestration
  preventing their conversion to methane
• There are huge volumes of concrete produced
  annually (gt2 tonnes per person per year)

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Solving Waste Logistics Problems

• TecEco cementitious composites represent a cost
  affective option for
• using non traditional aggregates from on site
  reducing transports costs and emissions
• use and immobilisation of waste.
• Because they have
• Lower reactivity
• less water
• lower pH
• Reduced solubility of heavy metals
• less mobile salts
• Greater durability.
• Denser.
• Impermeable (tec-cements).
• Dimensionally more stable with less shrinkage and
  cracking.
• Homogenous.
• No bleed water.

TecEco Technology - Converting Waste to Resource
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Recycling Materials Reduced Embodied Energies
and Emissions
The above relationships hold true on a macro
scale, provided we can change the technology
paradigm to make the process of recycling much
more efficient economic.
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TecEco Technology in Practice - Whittlesea, Vic.
Australia

• First Eco-cement mud bricks and mortars in
  Australia
• Tested up twice as strong as the PC controls
• Mud brick addition rate 2.5
• Addition rate for mortars 18 not 13 because of
  molar ratio volume increase with MgO compared to
  lime.

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TecEco Technology in Practice - Whittlesea, Vic.
Australia

• On 17th March 2005 TecEco poured the first
  commercial slab in the world using tec-cement
  concrete.
• The formulation strategy was to adjust a standard
  20 MPa high fly ash (36) mix from the supplier
  as a basis of comparison.
• Strength development, and in particular early
  strength development was good.
• Shrinkage was low.
• First Eco-cement mud bricks and mortars
• Tested up twice as strong as the PC controls
• Mud brick addition rate 2.5
• Rate for mortars 18 not 13 because of molar
  ratio increase.

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Blocks also available
TecEco tec and eco-cement blocks are now being
made commercially in Tasmania and with freight
equalization may be viable to ship to Victoria
for your green project. Hopefully soon we will
have a premix mortar available that uses
eco-cement.
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Eco-Cement Porous Pavement A Solution for Water
Quality?
Porous Pavements are a Technology Paradigm Change
Worth Investigating
Before three were cites forests and grassland
covered most of our planet. When it rained much
of the water naturally percolated though soils
that performed vital functions of slowing down
the rate of transport to rivers and streams,
purifying the water and replenishing natural
aquifers. Our legacy has been to pave this
natural bio filter, redirecting the water that
fell as rain as quickly as possible to the sea.
Given global water shortages, problems with
salinity, pollution, volume and rate of flow of
runoff we need to change our practices so as to
mimic the way it was for so many millions of
years before we started making so many changes.
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Earthship Brighton First Building to Use
Eco-Cements Throughout
Conclusion As materials scientists we must do all
we can to change the technology paradigms so that
carbon and wastes become resources. TecEco are
mimicking nature where the principle building
materials for trees, animals and fish has been
for millennia carbon Aubrey John Weston Harrison
B.Sc. B.Ec. FCPA.