John Harrison, TecEco Pty. Ltd., Tasmania, Australia

1
Huge markets for magnesia in concretes and other
cementitious composites

• John Harrison, TecEco Pty. Ltd., Tasmania,
  Australia

Presentation downloadable from www.tececo.com
2
New Uses New Markets

• Demand in this industry has been static for some
  years. New markets can change all that.
• Demand for Caustic Calcined and Less Reactive
  Grades through growth in the production and use
  of MgO boards
• Based on magnesium oxychloride/sulfate cements
  or Mg phosphate cements
• Reinforced with natural and synthetic fibres.
• Huge potential demand for cements using reactive
  MgO
• Discovery that reactive MgO could be blended with
  other hydraulic binders such as Portland cement
  or pozzolans. (Patented TecEco -Harrison)
• A powerful and useful new tool in cement
  chemistry affecting all properties including
  rheology, bleeding, dimensional stability and
  durability to name but a few.
• Rekindled interest in environmentally friendly
  magnesium carbonate cements.
• Eco-Cements with a high proportion of reactive
  MgO (Patented TecEco - Harrison)
• Reactive MgO 95 5 Hydraulic cement e.g. PC 5 -
  95.
• Pure reactive MgO cements (Cambidge Uni Group.
  Old technology revisited)
• Magnesium oxy chloro carbonate cements. (Imperial
  College Novacem. Old technology with a new spin?)

3
New Demand for New Forms of MgO

• Reactive Magnesia
• MgO calcined below say about 750 oC and fine
  ground to say ltlt45 micron. Engineered particle
  size, size range and reactivity.
• Including nano sizes or separate category?
• Caustic Calcined MgO
• MgO light burned at less that say 1000 oC and
  ground relatively fine say lt75 micron
• Dead Burned MgO
• MgO high temperature calcined, mostly periclase
  and often ground lt 100 micron.
• Fused

Reactivity
Lat t ice Energy
Focus on new uses for reactive MgO
Reactivity is a function of the energy input
(temperature of calcination time heat applied),
impurities, grind size, ore characteristics and
other factors. The actual energy input is most
important as energy in excess of that required to
break the MgCO3 bond goes into lattice energy
4
Why Reactive MgO?
Lattice energy Periclase gt Hydration energy
Mg  3795 kJ/mol-1  gt 1926 kJ/mol-1
In solution in the first hydration shell six
water molecules are held tightly in place by
electrostatic interactions between the two
positive charges on the Mg ion and the partial
negative charge on the oxygen molecule of each
water. This structure electrostatically
propagates outward many layers deep.
Periclase has a high lattice energy and both
cations and anions are in octahedral (6)
coordination.
The specific surface area of MgO is a proxy for
lattice energy and the lower the temperature of
calcination the more reactive the MgO.
Rapid formation of hydrated magnesium carbonates.
Rapid formation of Brucite
e.g Tec-Cements e.g Eco-cements
See Reactive Magnesia The Importance of the
Temperature of Calcination at http//www.tececo.co
m/technical.reactive_magnesia.php
5
Deployment of new Cements

• Quality issues
• A narrower bell curve of properties such as
  reactivity and particle size is required
• Price challenges
• Reactive magnesia must compete with Portland
  cement
• Environmental bureaucratic challenges
• Carbon caps or taxes will apply to emissions from
  the production of MgO

After inventing our Tec, Eco and Enviro cements
TecEco set out to figure out new ways of making
reactive MgO and design a kiln that could solve
the environmental sustainability challenge and in
the process we have solved the environmental,
carbon, quality and price issues as well
6
Making Cheaper Better Reactive MgO
Step Process Conditions Upsides Downsides
MgCO3gtMgO ?CO2 600-750 OC Known technology Emissions, fossil fuel energy. Blight on landscapes.
Step 1 of 2 Mg Silicate ?CO2 gt Mg Carbonate 180oC/150bar Sequestration step Fossil fuel energy?
Step 2 Mg Carbonate gt MgO ?CO2 650-750 OC Calcination step Process energy re release CO2
Optional Step before Mg Silicate gt Mg Salt (MgCl2) Various Known acid extraction Expensive As acid corrosive.
Step 1 of 2 Mg Salt ?CO2 gt Mg Carbonate (Nequehonite?) Room temp. Use waste. Carbon credits.
Step 2 of 2 Mg Carbonate gt MgO ?CO2 650-750 OC Calcination step Process energy re release CO2
Carbon neutral
TecEcoPref erred
We have to ask ourselves why we are still digging
holes in the ground. The industry would encounter
far less bureaucratic blocking, make more money
and go a long way towards solving global warming
using the last option in black with a light green
background.
7
The TecEco Tec-Kiln - Changing the Way we Make
Magnesia

• The Tec-Kiln is a top secret kiln being developed
  for low temperature calcination of alkali metal
  carbonates and the pyro processing and
  simultaneous grinding of other minerals such as
  clays.
• The TecEco Tec-Kiln makes no releases and is an
  essential part of TecEco's plan to sequester
  massive amounts of CO2 as man made carbonate in
  the built environment.
• The TecEco Tec-Kiln has the following features

• Operates in a closed system and therefore does
  not release CO2 or other volatiles substances to
  the atmosphere
• Can be powered by various potentially cheaper non
  fossil sources of energy such as intermittent
  solar or wind energy.
• Grinds and calcines at the same time thereby
  running 25 to 30 more efficiently.
• Produces more precisely definable product.
  (Secret as disclosure would give away the design)
• The CO2 produced can be sold or re-used.
• Cement made with the Tec-Kiln will be eligible
  for carbon offsets.

MgO
MgCO3
CO2
Tec-Kiln Problems Solved Way Forward
8
Gaia Engineering
Mg Carbonates
TecEco Tec-Kiln
Industrial CO2
MgO
Aggregates
Bitterns or Brines
TecEco Tec-Cements
TecEco Eco-Cements
MgCl2 Process
Building waste
Concretes and Other Composites
Built Environment
Other waste
9
New Players re CO2 Capture gt Building Materials

• 13th July 2002 Fred Pearce in New Scientist
  about TecEco technology
• THERE is a way to make our city streets as green
  as the Amazon rainforest. Almost every aspect of
  the built environment, from bridges to factories
  to tower blocks, and from roads to sea walls,
  could be turned into structures that soak up
  carbon dioxide- the main greenhouse gas behind
  global warming. All we need to do is change the
  way we make cement.
• 2008 - Calera Corporation
• Brett Constance backed by Vinod Khoshla and
  others
• Attracting considerable criticism from scientists
  as upsets pH balance resulting in reduced
  inability of oceans to absorb H2O (Ken Caldiera
  and others)
• Has so far produced the most expensive carbonate
  in the world
• 2008 - Greensols Process (Cuff and Blake)
• A fundamentally good idea stalled by lack of
  finance
• 2009 - Newcastle Group (Eric Kennedy and Others)
• Secretive

10
The Kyoto Process A Political and Economic
Dilemma
CO2 is adversely affecting climate
CO2 is adversely affecting climate
Action
Action
No
Yes
Yes
No
Cost GlobalRecessionSurvival
EconomicPoliticalSocialEnvironmentalCatastroph
e
EconomicPoliticalSocialEnvironmentalCatastroph
e
Profit
True
True
Cost GlobalRecession
Profit
Money Saved Survival
Profit
False
False
The TecEco Alternative
The Current Situation
A problem thats never been easy to come to grips
with and that our national and international
political systems were not designed to handle
By solving problems like global warming
profitably there is no dilemma and the world can
move forward
11
The Global Warming Problem
Global Carbon FlowsAfter David Schimel and Lisa
Dilling, National Centre for Atmospheric
Research 2003
The global CO2 budget is the balance of CO2
transfers to and from the atmosphere. The
transfers shown below represent the CO2 budget
after removing the large natural transfers (shown
to the right) which are thought to have been
nearly in balance before human influence.
Woods Hole Carbon Equation (In billions of metric
tonnes)
Atmospheric increase Emissions from fossil fuels Net emissions from changes in land use - Oceanic uptake - Missing carbon sink
3.2 (0.2) 6.3 (0.4) 2.2 (0.8) 2.4 (0.7) 2.9 (1.1)
From Haughton, R., Understanding the Global
Carbon Cycle. 2009, Woods Hole Institute at
http//www.whrc.org/carbon/index.htm
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Net Atmospheric Increase in Terms of Billion
Tonnes CO2
Using the Figures from Woods Hole on the Previous
Slide
Atmospheric increase Emissions from fossil fuels Net emissions from changes in land use - Oceanic uptake - Missing carbon sink
3.2 (0.2) 6.3 (0.4) 2.2 (0.8) 2.4 (0.7) 2.9 (1.1)
Converting to tonnes CO2 in the same units by
multiplying by 44.01/12.01, the ratio of the
respective molecular weights.
Atmospheric increase Emissions from fossil fuels Net emissions from changes in land use - Oceanic uptake - Missing carbon sink
11.72 (0.2) 23.08 (0.4) 8.016 (0.8) 8.79 (0.7) 10.62 (1.1)
From the above the annual atmospheric increase of
CO2 is in the order of 12 billion metric tonnes.
13
How Much Man Made Carbonate to Solve Global
Warming?

• If a proportion of the built environment were man
  made carbonate, how much would we need to reverse
  global warming?

MgO H2O gt Mg(OH)2 CO2 2H2O gt
MgCO3.3H2O40.31 18(l) gt 58.31 44.01(g) 2
X 18(l) gt 138.368 molar masses.44.01 parts by
mass of CO2 138.368 parts by mass MgCO3.3H2O1
138.368/44.01 3.14412 billion tonnes CO2
37.728 billion tonnes of nesquehonite or MgO
H2O gt Mg(OH)2 CO2 2H2O gt MgCO340.31
18(l) gt 58.31 44.01(g) 2 X 18(l) gt 84.32
molar masses.CO2 MgCO344.01 parts by mass of
CO2 84.32 parts by mass MgCO31
84.32/44.01 1.915912 billion tonnes CO2
22.99 billion tonnes magnesite
14
So How Much Magnesia Would be Sold?
Not enough to show on graph
How Much Money How Much Magnesia X Price
Value Carbon Credits Costs Production
15
Natural Sinks for Carbon
This industry could profitably be involved in
modifying the carbon cycle by facilitating a new
man made carbon sink in the built environment.
The need for a new and very large sink can be
appreciated by considering the balance sheet of
global carbon in the crust after Ziock, H. J. and
D. P. Harrison depicted.
Modified from Figure 2 Ziock, H. J. and D. P.
Harrison. "Zero Emission Coal Power, a New
Concept." from http//www.netl.doe.gov/publication
s/proceedings/01/carbon_seq/2b2.pdf by the
inclusion of a bar to represent sedimentary sinks
16
Carbon Capture Carbon Credits
17
Understanding Magnesium Compounds including Nano
Composites
At http//www.tececo.com/technical.nanocomposites
.php we discuss the amazing ability of magnesium
hydroxide to form complex layered double
hydroxide (LDH) compounds with many other
substances including water and CO2. This property
is important because it is why for example
magnesium hydroxide hydrates can prevent
autogenous shrinkage of concrete and why
magnesia is so useful for locking up wastes. It
is also related to how it can bond so easily with
other substances.
After DSouza, N. A., P. Braterman, et al.
"Flame retardant nano composites with layer
double hydroxides."   Retrieved 15 October 2006,
2006.
Many magnesium compounds are characterised by a
mixture of Ionic and Polar Bonding and this
accounts for many of their properties
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Understanding Magnesium Compounds including Nano
Composites
Brucite. Polar bound layers of ionically bound
atoms
Brucite hydrates. Polar bound layers of
ionically bound atoms
Strongly differentially charged surfaces and
polar bound water account for many of the
properties of brcute
Cellulose
19
A Classification of Magnesium Cements - 1
1. Cements that rely on the chemical reaction of
magnesia with another component. 1.1 Reactions
causing the formation of magnesium oxychloride,
magnesium oxysulfate or derivatives. (Excluded in
claim 1) 1.1.1 As a base with chlorides or
sulfates. E.g Aluminum, magnesium, calcium, zinc
or copper chloride or sulfate. 1.1.2 As a base
with acids. e.g. Sulfuric or hydrochloric
acids 1.1.3. As a base with partially substituted
acids or salts containing chloride or sulfates.
e.g. Reaction with calcium aluminate trisulphate,
a double salt, delivering sulphate for the
formation of magnesium oxy sulfate. 1.2 Chemical
reaction or interaction with substances that
cause carbonation. 1.2.1 As a base with organic
substances delivering CO3--. e.g Carbonic acid.
(See also 1.3.1) 1.2.2 As a base with inorganic
substances delivering CO3--. e.g. Sodium
carbonate and calcium carbonate, CO2 or a
chemical that releases CO2. The CO2 which then
dissolves in water forming carbonic acid.
(Carbonic acid will force rapid carbonation of
magnesia whereby various magnesium carbonates are
formed in situ.) 1.3 Chemical reaction with
acidifying agents. 1.3.1 Organic acidifying
agents. E.g. Citric acid, acetic acid and other
carboxylic or polycarboxylic acids. (Such organic
acidifying agents may also deliver carbonate
(CO3--.) and thus fall into the category 1.2.1
above.) 1.3.2 Inorganic acidifying agents.
Acidifying acids may assist the dissolution and
reformation of carbonate or act as accelerators
or retardants depending on the mix. 1.3.3 Neutrali
zation of acids e.g low molecular weight organic
acids from the breakdown of pectin and lignin in
wood prior to use of an ingredient such as in
this case wood 1.4 Cements that include an
soluble or acid phosphate and result in chemical
precipitation of insoluble magnesium
phosphates. 1.5 Chemical reaction in the form of
ion exchange. The use of magnesia for ion
replacement in a more soluble substance rendering
the substance less soluble. 1.5.1 The replacement
of Na or K is waterglass. e.g the replacement
of Na or K in sodium or potassium silicates
resulting in an insoluble precipitate of
magnesium silicate. 1.6 Chemical reaction as a so
called activator or accelerator (Note that
Mg is not a network former in geopolymeric
binders as claimed rather arbitrarily by
many.) 1.7 Cements that rely on prior addition of
magnesia to another substance resulting in
chemical and physical interaction sequentially
prior to the addition of other binder
components 1.7.1 The interaction of magnesia with
schist or the waste from coal washings prior to
the addition of other binders such as Portland
cement 1.7.2 The reaction of magnesia with low
molecular weight compounds e.g. wood acids prior
to further additions. 1.8 The reaction of
substances in a binder prior to addition of the
reactants to magnesia 1.9 Chemical interaction
with other salts (e.g. borax) 1.10 Interaction
with some other substance
Novacem
20
A Classification of Magnesium Cements - 2

• 2. Cements in which the main role of magnesia is
  in electrostatic bonding reactions. Cements that
  rely on the strong non-ionic, non covalent
  bonding of Mg to a negative region of a
  molecule. E.g. Mg to oxygen - similar to
  hydrogen bonding.
• 2.1 Bonding of Mg to oxygen in cellullosic
  compounds and oxygen in water.
• 2.2 Bonding and complexing with water. The
  hydration energy of Mg is very high (Note1) In
  solution Mg complexes with water more readily
  than Ca forming ions of the general form
  Mg(H2O)N2. Mg can also hydroxylate forming
  H3O and MgOH and hydrated forms of MgOH. These
  complexes greatly affect the rheology of water
  particularly in the presence of substances
  displaying strong hydrogen bonding, wherein Mg
  is attracted to the net negative charge on
  oxygen.
• 2.3 Electrostatic and sorption bonding to
  activated carbon
• 3 Cements that use dead burned rather than
  reactive magnesia.
• 3.1 Cements that use dead burned rather than
  reactive magnesia to deliberately induce
  expansion.
• 4. Cements that rely on the physical properties
  of magnesia rather than reaction. E.g. Cements
  that use dead burned rather than reactive
  magnesia to increase fire retarding properties
• Cements that have a high proportion of calcium
  carbonate in them. (May also fall into 1.2.2
  above)
• 5.1 Cements that include magnesia sourced from
  dolomite or
• 5.2 Cements that have been blended to include
  calcium carbonate. (excluded as we teach this is
  obviously not desirable)
• 6. Cements that do not include another hydraulic
  cement. Cements that may include magnesia but do
  not include a hydraulic cement like Portland
  cement.
• 7. Citations in which the use of magnesia is
  incidental and unnecessary
• 8. Citations that are nothing whatsoever to do
  with the TecEco patent or for which insufficient
  information has been provided
• 9. Complex mechano or nano composites.

Note 1 Mg has a hydration energy of 1926
kJ/mol compared to 1579 kJ/mol for Ca 1,2.
Six water molecules in octahedral coordination
surround the Mg2 ion in a rigid first solvent
shell 3. For comparison, the exchange rate of
water in the hydration shell of Ca2 ions is
1000-fold faster than for Mg2 ions 4. Ref
1 Slaughter M, Hill RJ The influence of organic
matter in organogenic dolomitization. J Sed
Petrol 1991, 61296-303. Ref 2 Wright DT, Wacey
D Precipitation of dolomite using
sulphate-reducing bacteria from the Coorong
Region, South Australia Significance and
implications. Sedimentology 2005, 52987-1008.
Publisher Full Text Ref 3 Kluge S, Weston J
Can a hydroxide ligand trigger a change in the
coordination number of magnesium ions in
biological systems. Biochemistry 2005,
444877-4885. PubMed Abstract Publisher Full
Text Ref 4 Fenter P, Zhang Z, Park C, Sturchio
NC, Hu XM, Higgins SR Structure and reactivity
of dolomite (104)-water interface New insights
into th dolomite problem. Geochim Cosmochim Acta
2007, 71566-579. Publisher Full Text
21
Why MgO in Hydraulic Binder Systems?

• Mg in solution is
• strongly kosmotrophic gt profound effects on
  rheology
• increased surface tension reduces bleeding and
  thus early age plastic shrinkage.
• Long term shrinkage eliminated.
• Replaces free lime (Portlandite Ca(OH)2) in
  concretes
• Free lime (Portlandite, Ca(OH)2) in concretes is
  too reactive.
• In Tec-Cement binders free lime is encouraged to
  react with pozzolans forming more calcium
  silicate hydrates. It is replaced by brucite and
  brucite hydrates which take on the major
  function of long term pH control and eliminate
  autogenous shrinkage.
• Dramatically improves durability
• Lower solubility and reactivity (Eh pH
  conditions) of Brucite
• Expansive carbonation resulting in very tight
  surfaces preventing entry of aggressive ions.

22
Magnesium Compounds
Mineral (or Product) Formula Partial Pressures Ph Hard ness Habit
Brucite Mg(OH)2 10.2 2.5 - 3 Blocky pseudo hexagonal chrystals.
Brucite Hydrates Mg(OH)2.nH2O Not much known!
Dypingite Mg5(CO3)4(OH)25H2O Low CO2, H2O High? ? Platy or rounded rosettes
HydromagnesiteGiorgiosite Mg5(CO3)4(OH)24H2O High? 3.5 Include acicular, lathlike, platy and rosette forms
Artinite Mg2(CO3)(OH)23(H2O) 2.5 Bright, white acicular sprays
Magnesite MgCO3 3.9 Usually massive
Barringtonite MgCO32H2O 2.5 Glassy blocky crystals
Nesquehonite MgCO33H2O Presence H2O Variable? 2.5 Acicular prismatic needles
Lansfordite MgCO35H2O 2.5 Glassy blocky crystals
Carbonates
Note Many other possible forms. Abiotic and
biotic precipitation pathways and a lack of
thermodynamic optimisation data
23
Magnesium Carbonate Phases
24
Why Brucite in Dense Concretes?

• Brucite
• Improves rheology (see http//www.tececo.com/techn
  ical.rheological_shrinkage.php)
• Prevents shrinkage and cracking (see
  http//www.tececo.com/technical.rheological_shrink
  age.php)
• Provides pH and eH control. Reduced corrosion.
  Stabilises CSH with pozzolanic reaction
  (Encouraged)
• Provides early setting even with added pozzolans
• Relinguishes polar bound water for more complete
  hydration of PC (thereby preventing autogenous
  shrinkage?)

Pourbaix diagram steel reinforcing
Surface charge on magnesium oxide
MgO H2O gt Mg(OH)2
25
Why Nesquehonite in Carbonating Binder Systems?

• At 2.09 of the crust magnesium is the 8th most
  abundant element
• Nesquehonite
• Has an ideal shape that contributes strength to
  the microstructure of a concrete
• Forms readily at moderate and high pH in the
  presence of CSH, our catalyst. (Nucleation
  mechanism?)
• The hydration of PC gt alkalinity dramatically
  increasing theCO3-- levels that are essential
  for carbonation.
• Significant molar volumeexpansion.
• Captures more CO2 than Calcium
• Ideal wet dry conditions are easily and cheaply
  provided. Forced carbonation is not required
  (Cambridge uni and others)

Nesquehonite
3H2O CO3---- Mg gt MgCO33H2O
XRD Pattern Nesquehonite
26
TecEco Formulations

• Tec-Cements (5-20 MgO, 80-95 OPC)
• contain more Portland cement than reactive
  magnesia. Reactive magnesia hydrates in the same
  rate order as Portland cement forming Brucite
  which uses up excess water reducing the
  voidspaste ratio, increasing density and
  possibly raising the short term pH.
• Reactions with pozzolans are more affective.
  After much of the Portlandite has been consumed
  Brucite tends to control 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 (20-95 MgO, 80-5 OPC)
• contain more reactive magnesia than in
  Tec-Cements. Brucite in permeable 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 PC to
  eco-cements but in non permeable 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.

27
Conclusion

• To avoid carbon costs and other imposts maybe the
  industry should consider making MgO in different
  way.
• The industry can gain a competitive advantage by
  being the first to produce product without
  releases and utilising wastes .
• MgCl2 CO2 gt MgCO3.3H2O gt MgO CO2
• Magnesium oxide on hydration and/or carbonation
  becomes many different minerals all of which
  should be considered as products with huge
  marketing opportunities such as for carbon
  sequestration.
• There must be much more focussed research into
  this wide array of new products as they are sold
  into technical markets.
• MgO of better quality and lower price is required
  to compete with Portland cement.
• As in the cement industry the MgO industry should
  consider forming an association which at an
  industry level carries out the basic research
  required to move into new markets.