New Markets for Magnesium Compounds

1
New Markets for Magnesium Compounds
It is time to contemplate new technology
paradigms, new products and new organisational
structures
TecEco are in the business of using MgO to solve
sustainability problems economically. Sustainabili
ty will be the biggest business on the planet if
we want to survive the future.
Auguste Rodin The Thinker
I will have to race over some slides but the
presentation is always downloadable from the
TecEco web site if you missed something.
John Harrison B.Sc.
B.Ec. FCPA.
2
The Mg Compounds Industry
We have to be flexible- Tsoukatos, Michael,
Magmin 2005 Obvious role is to be technical
leaders- Bamas, Dominique, Magmin 2005We need
to be proactive innovatorsHarrison, John, Magmin
2005

• Characterized as being.
• Market acceptors not creators.
• Mature but volatile markets
• Not investing in innovation
• Submissive
• Dominique Bamas A tough industry for tough guys
• Unidentified industry representative Our
  investors do not want us to be innovative
• Misconception that the type of product is very
  much controlled by the type of ore
• TecEco kiln technology will allow departure from
  this situation.
• Failure to understand what reactive means
• CCM is a catch all word for anything that is not
  DBM or FM
• A new product category called reactive magnesia
  
• Many pages on the net featuring TecEco
• We hope to find yours there by the next industry
  conference if you can make genuine low
  temperature calcined reactive MgO
• Largely oblivious as to how carbon taxes and
  energy shortages will impact.
• The production of reactive magnesia could be the
  first major non fossil fuel driven industrial
  process.

3
Time to Innovate

• Mining methods?
• Production technologies
• TecEco kiln technology will make it possible to
  efficiently make consistent product from a wide
  variety of ores using non fossil fuel energy in a
  closed system allowing the capture of CO2 (Carbon
  taxes will not be a burden using the technology)
• Why then is it so hard to raise funds to develop
  the technology?
• Product development
• Most uses of MgO have not yet been invented or
  improved. (Bamas, Dominique, Magmin 2005 )
• TecEco tec, eco and enviro cements could be
  developed and deployed very quickly with the
  backing of the industry create substantial new
  markets using high silica or possible iron
  magnesia (often a waste stream) without much
  cost.
• The construction market will grow significantly
  with TecEco technology not shrink.

Leaders innovate. Managers react
4
Time to Contemplate?

• MagMin 2005 may be the first time ever that such
  a large group of magnesium compounds industry
  representatives have been together.
• We should all thank Mike ODriscoll and
  Industrial Minerals Magazine for this
  opportunity.
• There are obviously common industry issues e.g.
• Response to carbon taxes
• Competition product associations and lobby groups
  e.g.
• Portland cement industry putting out information
  to diffuse and confuse regarding TecEco
  technology, use of MgO for environmental
  remediation etc.
• Lobby groups having a disproportionate say on
  government committees etc.
• Research development and deployment.
• To develop new markets (e.g Tec and Eco-Cements).
• Energy issues.
• Government policy issues. E.g. the EU on OHS

5
Time to Form an Association?

• Why not use this venue with so many of you
  together to form an association.
• There should be three sub-groups representing
• Dead burned magnesia
• Caustic calcined magnesia
• Reactive magnesia.
• Collectively you will
• Counter the lobbying power of alternative
  competing industries such as the lime and
  Portland cement industries.
• Move from being market acceptors to a leading
  industry creating your own future.

6
Opportunities for the Magnesium Compounds Industry

• The Kyoto treaty came in to force on the 16th
  February, 2005.
• Signatory countries are legally bound to reduce
  worldwide emissions of six greenhouse gases
  (collectively) by an average of 5.2 below their
  1990 levels by the period 2008-2012.
• Sequestration is just as important as emissions
  reduction.
• Magnesium compounds are the ideal choice for
  mineral sequestration.
• The magnesium compounds industry can play a vital
  role
• Supplying reactive magnesia to the new
  sequestration market.
• Developing new and innovative technologies to
  make reactive magnesia using non fossil fuel
  energy.
• Championing the use of reactive magnesia for
  sequestration in eco-cements for the built
  environment and directly out of the air.
• Helping their respective countries meet their
  Kyoto commitments.

TecEco can help the industry adapt and grow its
own future
7
Partners in the Business Opportunity

• The magnesium compounds industry.
• The power industry and others who will be seeking
  to reduce carbon taxes.
• Global governments who can organize carbon
  credits.
• The role of the magnesium compounds industry
• Pressing to remove standards banning reactive
  magnesia in Portland cement.
• Advocating mineral sequestration.
• Taking a stand in the sequestration debate
  pointing out the advantages of magnesium
  compounds.
• Providing research Funds to develop TecEco
  technologies by.
• Taking advance licences.
• Buying a share in the company.

R D is not just about studying your competitors
product or markets. It can be about creating new
market space.
8
The Problem A Planet in Crisis
TecEco are in the BIGGEST Business on the Planet
- Solving Sustainability Problems Economically
A Planet in Crisis?
9
A Demographic Explosion
?
Undeveloped Countries
Developed Countries
Global population, consumption per capita and our
footprint on the planet is exploding.
10
Atmospheric Carbon Dioxide
11
Global Temperature Anomaly
12
The Techno-Process
Earth Systems Atmospheric composition, climate,
land cover, marine ecosystems, pollution, coastal
zones, freshwater systems, salinity and global
biological diversity have all been substantially
affected.
Our linkages to the bio-geo-sphere are defined by
the techno process describing and controlling the
flow of matter and energy. It is these flows that
have detrimental linkages to earth systems.
Detrimental affects on earth systems
Move 500-600 billion tonnesUse some 50 billion
tonnes
13
Ecological Footprint
Our footprint is exceeding the capacity of the
planet to support it. We are not longer
sustainable as a species and must change our ways
14
Impact of the Largest Material Flow - Cement and
Concrete

• Concrete made with cement is the most widely used
  material on Earth accounting for some 30 of all
  materials flows on the planet and 70 of all
  materials flows in the built environment.
• Global Portland cement production is in the order
  of 2 billion tonnes per annum.
• Globally over 14 billion tonnes of concrete are
  poured per year.
• Over 2 tonnes per person per annum

TecEco Pty. Ltd. have benchmark technologies for
improvement in sustainability and properties
15
Embodied Energy of Building Materials
Concrete is relatively environmentally friendly
and has a relatively low embodied energy
Downloaded from www.dbce.csiro.au/ind-serv/brochur
es/embodied/embodied.htm (last accessed 07 March
2000)
16
Average Embodied Energy in Buildings
Most of the embodied energy in the built
environment is in concrete.
But because so much is used there is a huge
opportunity for sustainability by reducing the
embodied energy, reducing the carbon debt (net
emissions) and improving properties.
Downloaded from www.dbce.csiro.au/ind-serv/brochur
es/embodied/embodied.htm (last accessed 07 March
2000)
17
Emissions from Cement Production

• Chemical Release
• The process of calcination involves driving off
  chemically bound CO2 with heat.
• CaCO3 ?CaO ?CO2
• ?
• Process Energy
• Most energy is derived from fossil fuels.
• Fuel oil, coal and natural gas are directly or
  indirectly burned to produce the energy required
  releasing CO2.
• The production of cement for concretes accounts
  for around 10(1) of global anthropogenic CO2.
• (1) Pearce, F., "The Concrete Jungle Overheats",
  New Scientist, 19 July, No 2097, 1997 (page 14).

18
Cement Production Carbon Dioxide Emissions
19
Sustainability

• Sustainability is a direction not a destination.
• Our approach should be holistically balanced and
  involve
• Everybody, every process, every day.

Eco-cements Low Emissions ProductionMineral
Sequestration Waste utilization
Emissions reductionthrough efficiency
andconversion to non fossil fuels
Geological Seques-tration
TecEcos Contribution
20
Sustainability Culture Technology
Increase in demand/price ratio for sustainability
due to educationally induced cultural drift.

Supply
Greater Value/for impact (Sustainability) and
economic growth
Equilibrium shift
ECONOMICS
Demand
Increase in supply/price ratio for more
sustainable products due to innovative paradigm
shifts in technology.

Sustainability is where Culture and Technology
meet. Demand Supply
21
Huge Potential for Sustainable Materials in the
Built Environment

• The built environment is made of materials and is
  our footprint on earth.
• It comprises buildings and infrastructure.
• Building materials comprise
• 70 of materials flows (buildings, infrastructure
  etc.)
• 40-45 of waste that goes to landfill (15 of
  new materials going to site are wasted.)
• Reducing the impact of the take and waste phases
  of the techno-process.
• By including carbon in materialsthey are
  potentially carbon sinks.
• By including wastes forphysical properties
  aswell as chemical compositionthey become
  resources

22
Innovative New Technologies Vital

• It is possible to achieve Kyoto targets as the UK
  are proving, but we need to go way beyond the
  treaty according to our chief scientists.
• Carbon rationing has been proposed as the only
  viable means to keep the carbon dioxide
  concentration in the atmosphere below 450 ppm.
• Atmospheric carbon reduction is essential, but
  difficult to politically achieve by rationing.
• Making the built environment not only a
  repository for recyclable resources (referred to
  as waste) but a huge carbon sink is an
  alternative and adjunct that is politically
  viable as it potentially results in economic
  benefits.
• Concrete, a cementitous composite, is the single
  biggest material flow on the planet with over 2.2
  tonnes per person produced.
• Eco-cements offer tremendous potential for
  capture and sequestration using cementitious
  composites.
• Tec-Kiln technology vital to lower costs and make
  more reactive Mg compounds

23
TecEco Technologies

• 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
EconomicunderKyoto?
TecEco
24
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.
Silicic Acids or Silica
Magnesite (MgCO3)
Simplified TecEco ReactionsTec-Kiln MgCO3 ? MgO
CO2 - 118 kJ/moleReactor Process MgO CO2 ?
MgCO3 118 kJ/mole (usually more complex
hydrates)
Solar or Wind Electricity 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
25
Why Magnesium Compounds?

• 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.
• Magnesium minerals are relatively abundant.
• Magnesium minerals are potential low cost. New
  kiln technology from TecEco will enable low cost
  simple non fossil fuel calcination with CO2
  capture of magnesium carbonate.
• Because large quantities of carbonates (the
  binder in eco-cements) are produced from not much
  MgO. (The volumetric expansion from MgO to
  MgCO3.5H2O is 811 )

26
Why Magnesium Compounds (2)?

• At 2.09 of the crust magnesium is the 8th most
  abundant element.
• Magnesium oxide is easy to make using non fossil
  fuel energy using TecEco kiln technology.
• 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
  nearly six times more efficient.
• Use for sequestration directly and in the built
  environment would result in new and exciting
  markets for the magnesium compounds industry.

27
MgO Production at 10 of PC
Portland Cement Production
Possible Reactive Magnesia Production
At 10 substitution of PC by MgO 2005 world
production would have been 210 million tonnes
which is more than 100 times greater than current
production
The MgO could come from abundant silicates not
necessarily carbonates. A carbon credit would
apply for first carbonating a silicate then
calcining the resulting carbonate without
emitting CO2 to the atmosphere.
28
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

29
More Consistently Reactive MgO
Particle Size gt
A narrower distribution of reactivity is desirable
The current state of the art is a broad
distribution of reactivity
Reactivity gt
30
More Consistently Ground MgO
The current state of the art is a broad
distribution of particle size.
Particle Size gt
A narrower distribution of particle size is
desirable
Particle Size gt
31
A Post Carbon Age
The magnesium industry can be uniquely
responsible for helping achieve this transition
Molecular Biomimicry
32
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
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.
33
Drivers for Change Robotics

• Using Robots to print buildings is all quite
  simple from a software, computer hardware and
  mechanical engineering point of view.
• The problem is in developing new construction
  materials with the right flow characteristics so
  they can be squeezed out like toothpaste, yet
  retain their shape until hardened
• Once new materials suitable for the way robots
  work have been developed economics will drive the
  acceptance of robots for construction
• Concretes for example will need to evolve from
  being just a high strength grey material, to a
  smorgasbord of composites that can be squeezed
  out of a variety of nozzles for use by a robotic
  workforce for the varying requirements of a
  structure

• TecEco cement concretes have the potential of
  achieving the right shear thinning
  characteristics required

34
Benefits of Adopting TecEco Technology

• We can meet Kyoto objectives and at the same time
  reduce our footprint and make money.
• There are a number of opportunities for improved
  sustainability that are relatively easily
  achieved with MgO
• Utilizing wastes to make concretes.
• Fly ash, bottom ash, industrial slags etc. (Tec
  and Eco-Cements.)
• Reducing energy and emissions during the
  production of cements.
• Sequestering carbon by allowing MgO to
  re-carbonate.

The biggest business on the planet is going to be
the sustainability business
35
The Role of the Magnesium Compounds Industry

• The use of reactive MgO for sequestration
  directly (as magnesium hydroxide used to scrub
  CO2 out of the air) and as tec, eco and enviro
  cements in the built environment could
  potentially increase the market to in the order
  of millions of tonnes especially for lower purity
  grades (e.g. High SiO2).
• Players in the magnesium compound industry of the
  future will need to understand and get involved
  in sustainability issues and what TecEco are
  doing. Making sure
• Mineral sequestration research, development and
  deployment remain on track as the physical
  outcome the supply of large amounts of
  magnesium carbonate will reduce mining costs
  considerably.
• The development of tec and eco-cements occurs as
  large quantities of reactive reactive MgO will be
  required for this purpose.
• Enabling technologies such as the TecEco kiln are
  developed as they will allow production of the
  highly reactive magnesia required and reduce the
  cost base of manufacture.
• There are significant outcomes requiring
  significant commitment and a vision for the
  future.

36
TecEco Cements
More slides on web site
More information at www.tececo.com
37
TecEco Cements
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.
38
The Magnesium Thermodynamic Cycle
39
TecEco Cements - Sustainability in The Built
Environment

• The CO2 released by calcined carbonates used to
  make binders can be captured using TecEco kiln
  technology.
• Tec-Cements Develop Significant Early Strength
  even with Added Supplementary Materials.
• Around 25 30 less total binder is required for
  the same strength.
• Eco-cements carbonate sequestering CO2
• Both tec and ecocements provide a benign low pH
  environment for hosting large quantities of waste
  overcoming problems of
• Using acids to etch plastics so they bond with
  concretes.
• sulphates from plasterboard etc. ending up in
  recycled construction materials.
• heavy metals and other contaminants.
• delayed reactivity e.g. ASR with glass cullet
• Durability issues

40
TecEco Formulations

• Tec-cements (Low MgO)
• 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 (High MgO)
• 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 (High MgO)
• 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.

41
TecEco Cement Technology

• Portlandite (Ca(OH)2) is too soluble, mobile and
  reactive.
• It carbonates, reacts with Cl- and SO4- and being
  soluble can act as an electrolyte.
• TecEco generally (but not always) remove
  Portlandite using the pozzolanic reaction and
• TecEco add reactive magnesia
• which hydrates forming brucite which is another
  alkali, but much less soluble, mobile or reactive
  than Portlandite.
• In Eco-cements brucite carbonates

The consequences of need to be considered.
42
Why Add Reactive Magnesia?

• To maintain the long term stability of CSH.
• Maintains alkalinity preventing the reduction in
  Ca/Si ratio.
• To remove water.
• Reactive magnesia consumes water as it hydrates
  to possibly hydrated forms of brucite.
• To reduce shrinkage.
• The consequences of putting brucite through the
  matrix of a concrete in the first place need to
  be considered.
• To make concretes more durable
• Because significant quantities of carbonates are
  produced in porous substrates which are affective
  binders.

Reactive MgO is a new tool to be understood with
profound affects on most properties
43
Overcoming Dogma

• In 1917 the US National Bureau of Standards (now
  the National Bureau of standards and Technology)
  and the American Society for Testing Materials
  established a standard formula for Portland
  cement which excluded MgO in any form.
• We now know that it is lattice energy that causes
  the difference between amorphous magnesia and
  periclase
• TecEco have proved that amorphous magnesia,
  having no lattice energy to overcome, is safe to
  use in hydraulic binder cement systems
• Standards still ban any form of MgO in concretes
  to the detriment of the industry.
• This perception is something the magnesium
  compounds industry must overcome .

44
Lattice Energy Destroys a Myth

• Magnesia, provided it is reactive rather than
  dead burned (or high density, crystalline
  periclase type), can be beneficially added to
  cements in excess of the amount of 5 mass
  generally considered as the maximum allowable by
  standards prevalent in concrete dogma.
• Reactive magnesia is essentially amorphous
  magnesia with low lattice energy.
• It is produced at low temperatures and finely
  ground, and
• will completely hydrate in the same time order as
  the minerals contained in most hydraulic cements.
• Dead burned magnesia and lime have high lattice
  energies
• Crystalline magnesium oxide or periclase has a
  calculated lattice energy of 3795 Kj mol-1 which
  must be overcome for it to go into solution or
  for reaction to occur.
• Dead burned magnesia is much less expansive than
  dead burned lime (Ramachandran V. S., Concrete
  Science, Heydon Son Ltd. 1981, p 358-360 )

45
Summary of Reactions Involved
We think the reactions are relatively independent.
Notice the low solubility of brucite compared to
Portlandite and that nesquehonite adopts a more
ideal habit than calcite aragonite
46
Strength with Blend Porosity
Tec-cement concretes
Eco-cement concretes
High Porosity
Enviro-cement concretes
High Magnesia
High OPC
STRENGTH ON ARBITARY SCALE 1-100
47
Tec-Cement Concrete Strength Gain Curve

• Concretes are more often than not made to
  strength.
• The use of tec-cement results in
• 20-30 greater strength or less binder for the
  same strength.
• more rapid early strength development even with
  added pozzolans.
• Straight line strength development for a long time

strength gain with less cement and added
pozzolans is of great economic and environmental
importance.
48
Reasons for Strength Development in Tec-Cements.

• Reactive magnesia requires considerable water to
  hydrate resulting in
• Denser, less permeable concrete.
• A significantly lower voids/paste ratio.
• Higher early pH initiating more effective
  silicification reactions?
• The Ca(OH)2 normally lost in bleed water is used
  internally for reaction with pozzolans.
• Super saturation of alkalis caused by the removal
  of water?
• Micro-structural strength due to particle packing
  (Magnesia particles at 4-5 micron are a little
  over ½ the size of cement grains.)
• Slow release of water from hydrated Mg(OH)2.nH2O
  supplying H2O for more complete hydration of C2S
  and C3S?
• Formation of MgAl hydrates? Similar to flash set
  in concrete but slower??
• Formation of MSH??

49
Water Reduction During the Plastic Phase
Water is required to plasticise concrete for
placement, however once placed, the less water
over the amount required for hydration the
better. Depending on grind size magnesia consumes
more water as it hydrates than is required
because of its fineness.
Less water results in less shrinkage and cracking
and improved strength and durability.
Concentration of alkalis and increased density
result in greater strength.
50
Tec-Cement Compressive Strength
Graphs by Oxford Uni Student
51
Tec-Cement Tensile Strength
Graphs by Oxford Uni Student
Tensile strength is thought to be caused by
change in surface charge on MgO particles from
ve to ve at Ph 12 and electrostatic attractive
forces
52
Other Strength Testing to Date

• BRE (United Kingdom)
• 2.85PC/0.15MgO/3pfa(1 part) 3 parts sand -
  Compressive strength of 69MPa at 90 days.
• Note that there was as much pfa as Portland
  cement plus magnesia. Strength development was
  consistently greater than the OPC control
• TecEco Large Cement Company

Modified 20 MPa mix
53
Increased Density Reduced Permeability

• Concretes have a high percentage (around 18 -
  25) of voids.
• On hydration magnesia expands 116.9 filling
  voids and surrounding hydrating cement grains and
  compensates for the shrinkage of Portland cement.
• Brucite is 44.65 mass water.
• Lower voidspaste ratios than waterbinder ratios
  result in little or no bleed water less
  permeability and greater density.
• Compare the affect to that of vacuum dewatering.

54
Reduced Permeability

• As bleed water exits ordinary Portland cement
  concretes it creates an interconnected pore
  structure that remains in concrete allowing the
  entry of aggressive agents such as SO4--, Cl- and
  CO2
• TecEco tec - cement concretes are a closed
  system. They do not bleed as excess water is
  consumed by the hydration of magnesia.
• Consequences
• Tec - cement concretes tend to dry from within,
  are denser and less permeable and therefore
  stronger more durable and more waterproof. Cement
  powder is not lost near the surfaces.
• Tec-cements have a higher salt resistance and
  less corrosion of steel etc.

55
Tec-Cement pH Curves
56
Lower More Stable Long Term pH with Less Corrosion
In TecEco cements the long term pH is governed by
the low solubility and carbonation rate of
brucite and is much lower at around 10.5 -11,
allowing a wider range of aggregates to be used,
reducing problems such as AAR and etching. The pH
is still high enough to keep Fe3O4 stable in
reducing conditions.
Eh-pH or Pourbaix Diagram The stability fields of
hematite, magnetite and siderite in aqueous
solution total dissolved carbonate 10-2M.
Steel corrodes below 8.9
57
Reduced Steel Corrosion

• Steel remains protected with a passive oxide
  coating of Fe3O4 above pH 8.9.
• A pH of over 8.9 is maintained by the equilibrium
  Mg(OH)2 ? Mg 2OH- for much longer than the pH
  maintained by Ca(OH)2 because
• Brucite does not react as readily as Portlandite
  resulting in reduced carbonation rates and
  reactions with salts.
• Concrete with brucite in it is denser and
  carbonation is expansive, sealing the surface
  preventing further access by moisture, CO2 and
  salts.
• Brucite is less soluble and traps salts as it
  forms resulting in less ionic transport to
  complete a circuit for electrolysis and less
  corrosion.
• Free chlorides and sulfates originally in cement
  and aggregates are bound by magnesium
• Magnesium oxychlorides or oxysulfates are formed.
  ( Compatible phases in hydraulic binders that are
  stable provided the concrete is dense and water
  kept out.)

58
Corrosion in Portland Cement Concretes
Both carbonation, which renders the passive iron
oxide coating unstable or chloride attack
(various theories) result in the formation of
reaction products with a higher electrode
potential resulting in anodes with the remaining
passivated steel acting as a cathode.
Passive Coating Fe3O4 intact
Corrosion Anode Fe ? Fe 2e-Cathode ½ O2
H2O 2e- ? 2(OH)-Fe 2(OH)- ? Fe(OH)2 O2 ?
Fe2O3 and Fe2O3.H2O (iron oxide and hydrated iron
oxide or rust)
The role of chloride in Corrosion Anode Fe ?
Fe 2e-Cathode ½ O2 H2O 2e- ? 2(OH)-Fe
2Cl- ? FeCl2FeCl2 H2O OH- ? Fe(OH)2 H
2Cl-Fe(OH)2 O2 ? Fe2O3 and Fe2O3.H2O Iron
hydroxides react with oxygen to form rust. Note
that the chloride is recycled in the reaction
and not used up.
59
Reduced Delayed Reactions

• A wide range of delayed reactions can occur in
  Portland cement based concretes
• Delayed alkali silica and alkali carbonate
  reactions
• The delayed formation of ettringite and
  thaumasite
• Delayed hydration of minerals such as dead burned
  lime and magnesia.
• Delayed reactions cause dimensional distress and
  possible failure.

60
Reduced Delayed Reactions (2)

• Delayed reactions do not appear to occur to the
  same extent in TecEco cements.
• A lower long term pH results in reduced
  reactivity after the plastic stage.
• Potentially reactive ions are trapped in the
  structure of brucite.
• Ordinary Portland cement concretes can take years
  to dry out however the reactive magnesia in
  Tec-cement concretes consumes unbound water from
  the pores inside concrete, probably holding it
  for slow release to extended hydration reactions
  of Ca silicates.
• Magnesia dries concrete out from the inside.
  Reactions do not occur without water.

61
Durability - Reduced Salt Acid Attack

• Brucite has always played a protective role
  during salt attack. Putting it in the matrix of
  concretes in introduces considerable durability.
• Brucite does not react with salts because it is a
  least 5 orders of magnitude less soluble, mobile
  or reactive.
• Ksp brucite 1.8 X 10-11
• Ksp Portlandite 5.5 X 10-6
• TecEco cements are more acid resistant than
  Portland cement
• This is because of the relatively high acid
  resistance (?) of Lansfordite and nesquehonite
  compared to calcite or aragonite

62
Non Newtonian Rheology
The addition of finely ground reactive magnesia
results in Bingham plastic rheology.
This is mainly due to electrostatic charge affects
63
Non Newtonian Rheology
The strongly positively charged small Mg atoms
attract water (which is polar) in deep layers
affecting the rheological properties and making
concretes less sticky with added pozzolan
It is not known how deep these layers get
Etc.
Etc.
Ca 114, Mg 86 picometres
64
Rheology

• TecEco concretes and mortars are
• Very homogenous and do not segregate easily. They
  exhibit good adhesion and have a shear thinning
  property.
• Exhibit Bingham plastic qualities and react well
  to energy input.
• Have good workability.
• TecEco concretes with the same water/binder ratio
  have a lower slump but greater plasticity and
  workability.

• A range of pumpable composites with Bingham
  plastic properties will be required in the future
  as buildings will be printed. (See slides on
  Robotics)

65
Reduced Shrinkage
Net shrinkage is reduced due to stoichiometric
expansion of Magnesium minerals, and reduced
water loss.
Dimensional change such as shrinkage results in
cracking and reduced durability
66
Reduced Shrinkage Less Cracking
Cracking, the symptomatic result of shrinkage, is
undesirable for many reasons, but mainly because
it allows entry of gases and ions reducing
durability. Cracking can be avoided only if the
stress induced by the free shrinkage strain,
reduced by creep, is at all times less than the
tensile strength of the concrete. Tec-cements
also have greater tensile strength.
Large Cement Company
Tec-cements exhibit higher tensile strength and
less shrinkage and therefore less cracking
67
Volume Changes on Hydration

• When magnesia hydrates it expands
• MgO (s) H2O (l) ? Mg(OH)2.nH2O (s)
• 40.31 18.0 ? 58.3 (minimum)
  molar mass
• 11.2 liquid ? 24.3 (minimum) molar
  volumes
• A minimum of 116.96 solidus expansion depending
  on whether the water is coming from
  stoichiometric mix water, bleed water or from
  outside the system. In practice less as the water
  comes from mix and bleed water.

The molar volume (L.mol-1)is equal to the molar
mass (g.mol-1) divided by the density (g.L-1).
68
Volume Changes on Carbonation

• Consider what happens when Portlandite
  carbonates
• Ca(OH)2 CO2 ? CaCO3
• 74.08 44.01 ? 100 molar mass
• 33.22 gas ? 36.93 molar volumes
• Slight expansion. But shrinkage from surface
  water loss
• Compared to brucite forming nesquehonite as it
  carbonates
• Mg(OH)2 CO2 ? MgCO3.3H2O
• 58.31 44.01 ? 138.32 molar mass
• 24.30 gas ? 74.77 molar volumes
• 307 expansion (less water volume reduction) and
  densification of the surface preventing further
  ingress of CO2 and carbonation. Self sealing?

The molar volume (L.mol-1)is equal to the molar
mass (g.mol-1) divided by the density (g.L-1).
69
Dimensionally Control Over Concretes During
Curing?

• Portland cement concretes shrink around .05.
  Over the long term much more (gt.1).
• Mainly due to plastic and drying shrinkage.
• The use of some wastes as aggregates causes
  shrinkage e.g. wood waste in masonry units, thin
  panels etc.
• By varying the amount and form of magnesia added
  dimensional control can be achieved.

70
TecEco Cement Concretes Dimensional Control

• Combined Hydration and Carbonation can be
  manipulated to be close to neutral.
• So far we have not observed significant shrinkage
  in TecEco tec - cement concretes (5 -10
  substitution OPC) also containing fly ash.
• At some ratio, thought to be around 10 reactive
  magnesia and 90 PC volume changes are optimised
  as higher additions of MgO reduce strength.
• The water lost by Portland cement as it shrinks
  is used by reactive magnesia as it hydrates also
  reducing shrinkage.

71
Tec - Cement Concretes Less or no Dimensional
Change
It may be possible to engineer a particle with
slightly delayed expansion to counterbalance the
expansion and then shrinkage concretes containing
gbfs.
72
Tec-Cement - Less Freeze - Thaw Problems

• Denser concretes do not let water in.
• Brucite will to a certain extent take up internal
  stresses
• When magnesia hydrates it expands into the pores
  left around hydrating cement grains
• MgO (s) H2O (l) ? Mg(OH)2 (s)
• 40.31 18.0 ? 58.3 molar
  mass
• 11.2 18.0 ? 24.3 molar
  volumes
• 39.20 ? 24.3 molar volumes
• 38 air voids are created in space that was
  occupied by magnesia and water!
• Air entrainment can also be used as in
  conventional concretes
• TecEco concretes are not attacked by the salts
  used on roads

73
Eco-Cements - Utilizing Carbon as a Binder

• The concept of using carbon as a binder is not
  new.
• Ancient and modern carbonating lime mortars are
  based on this principle.
• TecEco have now taken the concept a lot further
  however with the development of eco-cement which
  is based on blending reactive magnesium oxide
  with other hydraulic cements. Eco-cements only
  carbonate in porous materials like 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.

74
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 nearly six times more
  efficient.
• Magnesium hydroxide in particular and to some
  extent the carbonates are less reactive and
  mobile and thus much more durable.

75
Eco-Cement pH Curves
76
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.

77
Eco-Cement Concrete 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.
78
Eco-Cement Micro-Structural Strength
79
Carbonation

• Because magnesium has a low molecular weight,
  proportionally a greater amount of CO2 is
  captured.
• Carbonation results in significant sequestration
  because of the shear volumes involved.
• Carbonation adds strength.
• Carbonates are the stable phases of both calcium
  and magnesium.
• The formation of carbonates lowers the pH of
  concretes compromising the stability of the
  passive oxide coating on steel.
• Some steel reinforced structural concrete could
  be replaced with fibre reinforced porous
  carbonated concrete.

80
Chemistry of Carbonation

• 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.
81
Ramifications of Carbonation

• Magnesium Carbonates.
• The magnesium carbonates that form at the surface
  of tec cement concretes expand significantly
  thereby sealing off further carbonation.
• Lansfordite and nesquehonite are stronger and
  more acid resistant than calcite or aragonite.
• The curing of eco-cements in a moist - dry
  alternating environment seems to encourage
  carbonation.

82
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)
83
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)
84
Utilizing Wastes to Make Concretes

• Many wastes can contribute physical property
  values. Take plastics for example which are
  collectively light in weight, have tensile
  strength and low conductance.
• Tec, eco and enviro-cements will allow a wide
  range of wastes to be used for their physical
  property rather than chemical composition.
• Tec, enviro and eco-cements are
• low alkali reducing reaction problems with
  organic materials.
• stick well to most included wastes
• Carbon wastes such as sawdust and plastic if
  taken to landfill eventually becomes methane
  which is a greenhouse gas 21 times worse than
  CO2.
• Tec, enviro and eco-cements can utilize wastes
  including carbon to increase sequestration.

85
TecEco Binders - Solving Waste Problems

• There are huge volumes of concrete produced
  annually ( 2 tonnes per person per year.)
• An important objective should be to make
  cementitous composites that can utilise wastes.
• TecEco cements provide a benign environment
  suitable for waste immobilisation
• Many wastes such as fly ash, sawdust , shredded
  plastics etc. can improve a property or
  properties of the cementitious composite.

There are huge materials flows in both wastes and
building and construction. TecEco technology will
lead the world in the race to incorporate wastes
in cementitous composites
86
TecEco Binders - Solving Waste Problems (2)

• TecEco cementitious composites represent a cost
  affective option for both use and immobilisation
  of waste.
• 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
87
Role of Brucite in Immobilization

• In a Portland cement brucite matrix
• PC takes up lead, some zinc and germanium
• Brucite and hydrotalcite are both excellent hosts
  for toxic and hazardous wastes.
• Heavy metals not taken up in the structure of
  Portland cement minerals or trapped within the
  brucite layers end up as hydroxides with minimal
  solubility.

The brucite in TecEco cements has a structure
comprising electronically neutral layers and is
able to accommodate a wide variety of extraneous
substances between the layers and cations of
similar size substituting for magnesium within
the layers and is known to be very suitable for
toxic and hazardous waste immobilisation.
Layers of electronically neutral brucite suitable
for trapping balanced cations and anions as well
as other substances.
Van de waals bonding holding the layers together.
Salts and other substances trapped between the
layers.
88
Lower Solubility of Metal Hydroxides
There is a 104 difference
89
TecEco Materials as Fire Retardants

• The main phase in TecEco tec - cement concretes
  is Brucite.
• The main phases in TecEco eco-cements are
  Lansfordite and nesquehonite.
• Brucite, Lansfordite and nesquehonite are
  excellent fire retardants and extinguishers.
• At relatively low temperatures
• Brucite releases water and reverts to magnesium
  oxide.
• Mg(OH)2 ? MgO H2O
• Lansfordite and nesquehonite releases CO2 and
  water and convert to magnesium oxide.
• MgCO3.nH2O ? MgO CO2 H2O
• Fires are therefore not nearly as aggressive
  resulting in less damage to structures.
• Damage to structures results in more human losses
  that direct fire hazards.

90
TecEco Cement Implementation Summary
91
The Right Magnesia

• We are still exploring the boundaries as to the
  extent of MgO crystallization that can be
  tolerated without damaging delayed hydration in
  tec-cements. Eco-cements are more tolerant.
• Until we know more it is important that
  researchers use the most reactive MgO as they can
  get hold of.
• If you experience dimensional distress the MgO is
  not reactive enough.
• Be skeptical of producer specs as particle size
  and distribution is easily measured in the
  industry using laser-diffraction techniques and
  incorrectly considered by many to be the same
  thing as reactivity. It is not.
• We agree tests will need to be evolved and apart
  from neutralization of citric acid or
  phenolphthalein which would give no indication of
  a dangerous dead burned fraction consider that
  calorimetry offers the most promising method.
• Any input welcome!

92
High Performance-Lower Construction Costs

• Less binders (OPC magnesia) for the same
  strength.
• Faster strength gain even with added pozzolans.
• Elimination of shrinkage reducingassociated
  costs.
• Tolerance and consumption of water.
• Reduction in bleed water enables finishing of
  lower floors whilst upper floors still being
  poured and increases pumpability.
• Cheaper binders as less energy required
• Increased durability will result in lower
  costs/energies/emissions due to less frequent
  replacement.
• Because reactive magnesia is also an excellent
  plasticiser, other costly additives are not
  required for this purpose.
• A wider range of aggregates can be utilised
  without problems reducing transport and other
  costs/energies/emissions.

Foolproof Concrete?
93
TecEco Concretes - Lower Construction Costs (2)

• Homogenous, do not segregate with pumping or
  work.
• Easier placement and better finishing.
• Reduced or eliminated carbon taxes.
• Eco-cements can to a certain extent be recycled.
• TecEco cements utilise wastes many of which
  improve properties.
• Improvements in insulating capacity and other
  properties will result in greater utility.
• Products utilising TecEco cements such as masonry
  and precast products can in most cases utilise
  conventional equipment and have superior
  properties.
• A high proportion of brucite compared to
  Portlandite is water and of Lansfordite and
  nesquehonite compared to calcite is CO2.
• Every mass unit of TecEco cements therefore
  produces a greater volume of built environment
  than Portland and other calcium based cements.
  Less need therefore be used reducing
  costs/energy/emissions.

94
Summary

• Simple, smart and sustainable?
• TecEco cement technology has resulted in
  potential solutions to a number of problems with
  Portland and other cements including shrinkage,
  durability and corrosion and the immobilisation
  of many problem wastes and will provides a range
  of more sustainable building materials.
• The right technology at the right time?
• TecEco cement technology addresses important
  triple bottom line issues solving major global
  problems with positive economic and social
  outcomes.

95
TecEco Doing Things
96
The Use of Eco-Cements for Building Earthship
Brighton
By Taus Larsen, (Architect, Low Carbon Network
Ltd.) The Low Carbon Network (www.lowcarbon.co.uk)
was established to raise awareness of the links
between buildings, the working and living
patterns they create, and global warming and aims
to initiate change through the application of
innovative ideas and approaches to construction.
Englands first Earthship is currently under
construction in southern England outside Brighton
at Stanmer Park and TecEco technologies have been
used for the floors and some walling.
Earthships are exemplars of low-carbon design,
construction and living and were invented and
developed in the USA by Mike Reynolds over 20
years of practical building exploration. They are
autonomous earth-sheltered buildings independent
from mains electricity, water and waste systems
and have little or no utility costs. For
information about the Earthship Brighton and
other projects please go to the TecEco web site.
97
Repair of Concrete Blocks. Clifton Surf Club
The Clifton Surf Life Saving Club was built by
first pouring footings, On the footings block
walls were erected and then at a later date
concrete was laid in between. As the ground
underneath the footings was sandy, wet most of
the time and full of salts it was a recipe for
disaster. Predictably the salty water rose up
through the footings and then through the blocks
and where the water evaporated there was strong
efflorescence, pitting, loss of material and
damage.
The TecEco solution was to make up a formulation
of eco-cement mortar which we doctored with some
special chemicals to prevent the rise of any more
moisture and salt. The solution worked well and
appears to have stopped the problem.
98
Mike Burdons Murdunna Works
Mike Burdon, Builder and Plumber. I work for a
council interested in sutainability and have been
involved with TecEco since around 2001 in a
private capacity helping with large scale testing
of TecEco tec-cements at our shack. I am
interested in the potentially superior strength
development and sustainability aspects. To date
we have poured two slabs, footings, part of a
launching ramp and some tilt up panels using
formulations and materials supplied by John
Harrison of TecEco. I believe that research into
the new TecEco cements essential as overall I
have found

• The rheological performance even without
  plasticizer was excellent. As testimony to this
  the contractors on the site commented on how easy
  the concrete was to place and finish.
• We tested the TecEco formulations with a hired
  concrete pump and found it extremely easy to pump
  and place. Once in position it appeared to gel
  up quickly allowing stepping for a foundation to
  a brick wall.
• Strength gain was more rapid than with Portland
  cement controls from the same premix plant and
  continued for longer.
• The surfaces of the concrete appeared to be
  particularly hard and I put this down to the fact
  that much less bleeding was observed than would
  be expected with a Portland cement only
  formulation

99
Tec-Cement Slab Whittlesea, Vic. Australia

• On 17th March 2005 TecEco poured the first
  commercial slab in the world using tec-cement
  concrete with the assistance of one of the larger
  cement and pre-mix companies.
• The formulation strategy was to adjust a standard
  20 MPa high fly ash (36) mix from the company as
  a basis of comparison.
• Strength development, and in particular early
  strength development was good. Interestingly some
  70 days later the slab is still gaining strength
  at the rate of about 5 MPa a month.
• Also noticeable was the fact that the concrete
  was not as "sticky" as it normally is with a fly
  ash mix and that it did not bleed quite as much.
• Shrinkage was low. 7 days - 133 micro strains, 14
  days - 240 micro strains, 28 days - 316 micros
  strains and at 56 days - 470 microstrains.

100
Embodied Energies and Emissions
101
Reducing Embodied Energy and Emissions

• 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.

We all use carbon and wastes to make our
homes! Molecular Biomimicry
102
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.
Aft