John Harrison, TecEco Pty. Ltd., Tasmania, Australia
Huge markets for magnesia in concretes and other
cementitious composites
Presentation downloadable from www.tececo.com
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?)
June 2010
Presentation downloadable from www.tececo.com
New Demand for New Forms of MgO
 Reactive Magnesia
 MgO calcined below say about 750
and fine ground
to say <<45 micron. Engineered particle size, size
range and reactivity.
oC
 Including nano sizes or separate category?
Focus on
new uses
for reactive
MgO
 Caustic Calcined MgO
 MgO “light burned” at less that say 1000 oC and
ground relatively fine say <75 micron
 Dead Burned MgO
 MgO high temperature calcined, mostly periclase and
often ground < 100 micron.
 Fused
L
a
t
t
i
c
e
E
n
e
r
g
y
R
e
a
c
t
i
v
i
t
y
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 Mg~CO3 bond goes into lattice energy
June 2010
Presentation downloadable from www.tececo.com
Why Reactive MgO?
Lattice energy Periclase > Hydration energy Mg++
3795 kJ/mol-1 > 1926 kJ/mol-1
Periclase has a high lattice energy
and both cations and anions are in
octahedral (6) coordination.
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.
Rapid formation of
Rapid
hydrated
formation of
magnesium
Brucite
carbonates.
e.g Tec-Cements
e.g Eco-cements
The specific surface
area of MgO is a
proxy for lattice
energy and the
lower the
temperature of
calcination the
more reactive the
See: Reactive Magnesia The Importance of the Temperature of
MgO.
Calcination at
http://www.tececo.com/technical.reactive_magnesia.php
June 2010
Presentation downloadable from www.tececo.com
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
June 2010
Presentation downloadable from www.tececo.com
Making Cheaper Better Reactive MgO
Step
Process
Conditions
Upsides
Downsides
MgCO3=>MgO +↑CO2
600-750 OC
Known
technology
Emissions, fossil fuel
energy. Blight on
landscapes.
Step 1 of
2
Mg Silicate + ↓CO2 => Mg
Carbonate
180oC/150bar
Sequestration
step
Fossil fuel energy?
Step 2
Mg Carbonate => MgO +
↑CO2
650-750 OC
Calcination
step
Process energy + re
release CO2
Optional
Step
before
Mg Silicate => Mg Salt
(MgCl2)
Various
Known acid
extraction
Expensive As acid
corrosive.
Step 1 of
2
Mg Salt + ↓CO2 => Mg
Carbonate (Nequehonite?)
Room temp.
Step 2 of
2
Mg Carbonate => MgO +
↑CO2
650-750 OC
Use waste.
Carbon
credits.
Calcination
step
Process energy + re
release CO2
Carbon
neutral
TecEco
Pref –
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.
June 2010
Presentation downloadable from www.tececo.com
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)
MgO
 The CO2 produced can be sold or re-used.
 Cement made with the Tec-Kiln will be eligible for carbon offsets.
MgCO3
CO2
Tec-Kiln = Problems Solved = Way Forward
June 2010
Presentation downloadable from www.tececo.com
Gaia Engineering
Industrial CO2
Mg
Carbonates
TecEco Tec-Kiln
MgO
Aggregates
Bitterns
or
Brines
TecEco
EcoCements
MgCl2
Process
Building
waste
Other waste
June 2010
TecEco
TecCements
Concretes and
Other Composites
Built Environment
Presentation downloadable from www.tececo.com
New Players re CO2 Capture = > 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
June 2010
Presentation downloadable from www.tececo.com
The Kyoto Process – A Political and Economic Dilemma
CO2 is
adversely
affecting
climate
True
Action
Yes
Cost $
Global
Recession
Survival
False
Cost $
Global
Recession
No
Economic
Political
Social
Environmental
Catastrophe
Money
Saved $
CO2 is
adversely
affecting
climate
Action
No
Yes
Profit $
Economic
Political
Social
Environmental
Catastrophe
Profit $
Profit $
True
False
Survival
The Current Situation
A problem that’s never been easy to
come to grips with and that our
national and international political
systems were not designed to handle
June 2010
The TecEco
Alternative
By solving problems like global
warming profitably there is no
dilemma and the world can move
forward
Presentation downloadable from www.tececo.com
The Global Warming Problem
Global Carbon Flows
After: 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)
Atmosp
heric
increase
3.2 (±0.2)
= Emissions from
fossil fuels
6.3 (±0.4)
+
Net emissions
from changes in
land use
2.2 (±0.8)
-
Oceanic
uptake
2.4 (±0.7)
-
Missing
carbon
sink
2.9 (±1.1)
From: Haughton, R., Understanding the Global Carbon Cycle. 2009, Woods Hole Institute at http://www.whrc.org/carbon/index.htm
June 2010
Presentation downloadable from www.tececo.com
Net Atmospheric Increase in Terms of Billion Tonnes CO2
Using the Figures from Woods Hole on the Previous Slide
Atmospheric
increase
=
3.2 (±0.2)
Emissions from
fossil fuels
+
6.3 (±0.4)
Net emissions from
changes in land use
-
2.2 (±0.8)
Oceanic
uptake
-
2.4 (±0.7)
Missing
carbon sink
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
11.72 (±0.2)
=
Emissions from
fossil fuels
23.08 (±0.4)
+
Net emissions from
changes in land use
8.016 (±0.8)
-
Oceanic
uptake
8.79 (±0.7)
-
Missing
carbon sink
10.62 (±1.1)
From the above the annual atmospheric increase of CO2 is in the
order of 12 billion metric tonnes.
June 2010
Presentation downloadable from www.tececo.com
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 => Mg(OH)2 + CO2 + 2H2O => MgCO3.3H2O
40.31 + 18(l) => 58.31 + 44.01(g) + 2 X 18(l) => 138.368 molar masses.
44.01 parts by mass of CO2 ~= 138.368 parts by mass MgCO3.3H2O
1 ~= 138.368/44.01= 3.144
12 billion tonnes CO2 ~= 37.728 billion tonnes of nesquehonite
or
MgO + H2O => Mg(OH)2 + CO2 + 2H2O => MgCO3
40.31 + 18(l) => 58.31 + 44.01(g) + 2 X 18(l) => 84.32 molar masses.
CO2 ~= MgCO3
44.01 parts by mass of CO2 ~= 84.32 parts by mass MgCO3
1 ~= 84.32/44.01= 1.9159
12 billion tonnes CO2 ~= 22.99 billion tonnes magnesite
June 2010
Presentation downloadable from www.tececo.com
So How Much Magnesia Would be Sold?
2E+10
1.8E+10
1.6E+10
1.4E+10
Tonnes
1.2E+10
Not enough
to show on
graph
1E+10
8E+09
6E+09
4E+09
2E+09
Magnesite Production
0
World Production Cement
Magnesia in Cement
Portland Cement in Cement
World Production Concrete
Source Cement Data: USGS Minerals Yearbooks.
Assume Concrete Includes 15% Cement
How Much Money = How Much Magnesia X Price + Value Carbon Credits – Costs Production
June 2010
Presentation downloadable from www.tececo.com
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/publications/proceedings/01/carbon_seq/2b2.pdf by the inclusion of a bar
to represent sedimentary sinks
June 2010
Presentation downloadable from www.tececo.com
Carbon Capture = Carbon Credits
June 2010
Presentation downloadable from www.tececo.com
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: D’Souza, 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
June 2010
Presentation downloadable from www.tececo.com
Understanding Magnesium Compounds including Nano Composites
Brucite.
Polar bound
layers of
ionically
bound
atoms
Cellulose
June 2010
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
Presentation downloadable from www.tececo.com
A Classification of Magnesium Cements - 1
1.
1.1
1.1.1
1.1.2
1.1.3.
1.2
1.2.1
1.2.2
1.3
1.3.1
1.3.2
1.3.3
1.4
1.5
1.5.1
1.6
1.7
1.7.1
1.7.2
1.8
1.9
1.10
Cements that rely on the chemical reaction of magnesia with another component.
Reactions causing the formation of magnesium oxychloride, magnesium oxysulfate or derivatives. (Excluded in claim 1)
Novacem
As a base with chlorides or sulfates. E.g Aluminum, magnesium, calcium, zinc or copper chloride or sulfate.
As a base with acids. e.g. Sulfuric or hydrochloric acids
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.
Chemical reaction or interaction with substances that cause carbonation.
As a base with organic substances delivering CO3--. e.g Carbonic acid. (See also 1.3.1)
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.)
Chemical reaction with acidifying agents.
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.)
Inorganic acidifying agents. Acidifying acids may assist the dissolution and reformation of carbonate or act as accelerators or retardants depending on the
mix.
Neutralization 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
Cements that include an soluble or acid phosphate and result in chemical precipitation of insoluble magnesium phosphates.
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.
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.
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.)
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
The interaction of magnesia with schist or the waste from coal washings prior to the addition of other binders such as Portland cement
The reaction of magnesia with low molecular weight compounds e.g. wood acids prior to further additions.
The reaction of substances in a binder prior to addition of the reactants to magnesia
Chemical interaction with other salts (e.g. borax)
Interaction with some other substance
June 2010
Presentation downloadable from www.tececo.com
A Classification of Magnesium Cements - 2
2.
2.1
2.2
2.3
3
3.1
4.
5.
5.1
5.2
6.
7.
8.
9.
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.
Bonding of Mg++ to oxygen in cellullosic compounds and oxygen in water.
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)N]2+. Mg++ can also hydroxylate forming H3O+ and Mg+OH and hydrated forms of Mg+OH. 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.
Electrostatic and sorption bonding to activated carbon
Cements that use dead burned rather than reactive magnesia.
Cements that use dead burned rather than reactive magnesia to deliberately induce expansion.
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)
Cements that include magnesia sourced from dolomite or
Cements that have been blended to include calcium carbonate. (excluded as we teach this is obviously not desirable)
Cements that do not include another hydraulic cement. Cements that may include magnesia but do not include a hydraulic cement like Portland cement.
Citations in which the use of magnesia is incidental and unnecessary
Citations that are nothing whatsoever to do with the TecEco patent or for which insufficient information has been provided
Complex mechano or nano composites.
Note 1
Ref 1
Ref 2
Ref 3
Ref 4
June 2010
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].
Slaughter M, Hill RJ: The influence of organic matter in organogenic dolomitization. J Sed Petrol 1991, 61:296-303.
Wright DT, Wacey D: Precipitation of dolomite using sulphate-reducing bacteria from the Coorong Region, South Australia: Significance
and implications. Sedimentology 2005, 52:987-1008. Publisher Full Text
Kluge S, Weston J: Can a hydroxide ligand trigger a change in the coordination number of magnesium ions in biological systems.
Biochemistry 2005, 44:4877-4885. PubMed Abstract | Publisher Full Text
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, 71:566-579. Publisher Full Text
Presentation downloadable from www.tececo.com
Why MgO in Hydraulic Binder Systems?
 Mg in solution is
 strongly kosmotrophic => 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.
June 2010
Presentation downloadable from www.tececo.com
Magnesium Compounds
Mineral (or
Product)
Formula
Partial
Pressures
Brucite
Mg(OH)2
Brucite Hydrates
Mg(OH)2.nH2O
Dypingite
Mg5(CO3)4(OH)2·5H2O
Hydromagnesite
Giorgiosite
Mg5(CO3)4(OH)2·4H2O
Artinite
Ph
Hard
ness
Habit
10.2
2.5 3
Blocky pseudo
hexagonal chrystals.
Not much known!
Low CO2,
H2O
High?
?
Platy or rounded
rosettes
High?
3.5
Include acicular,
lathlike, platy and
rosette forms
Mg2(CO3)(OH)2•3(H2O)
2.5
Bright, white acicular
sprays
Magnesite
MgCO3
3.9
Usually massive
Barringtonite
MgCO3·2H2O
2.5
Glassy blocky crystals
Nesquehonite
MgCO3·3H2O
2.5
Acicular prismatic
needles
Lansfordite
MgCO3·5H2O
2.5
Glassy blocky crystals
Presence
H2O
Variable?
Note: Many other possible forms. Abiotic and biotic precipitation pathways
and a lack of thermodynamic optimisation data
June 2010
Presentation downloadable from www.tececo.com
C
a
r
b
o
n
a
t
e
s
Magnesium Carbonate Phases
June 2010
Presentation downloadable from www.tececo.com
Why Brucite in Dense Concretes?
 Brucite
 Improves rheology (see
http://www.tececo.com/technical.rheological_shrinkage.
php)
 Prevents shrinkage and cracking (see
http://www.tececo.com/technical.rheological_shrinkage.
php)
 Provides pH and eH control. Reduced corrosion.
Stabilises CSH with pozzolanic reaction (Encouraged)
 Provides early setting even with added pozzolans
Pourbaix diagram steel reinforcing
 Relinguishes polar bound water for more complete
hydration of PC (thereby preventing autogenous
shrinkage?)
MgO + H2O => Mg(OH)2
June 2010
Surface charge on magnesium oxide
Presentation downloadable from www.tececo.com
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 => alkalinity dramatically increasing the
CO3-- levels that are essential for carbonation.
Nesquehonite
 Significant molar volume
expansion.
 Captures more CO2 than Calcium
CO 2
44

 52%
MgCO3
84
CO 2
44
-++

 43 % 3H2O + CO3 -- + Mg => MgCO3·3H2O
CaCO 3
101
 Ideal wet dry conditions are easily and cheaply provided. Forced
carbonation is not required (Cambridge uni and others)
June 2010
Presentation downloadable from www.tececo.com
XRD Pattern Nesquehonite
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 voids:paste 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 it’s 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.
June 2010
Presentation downloadable from www.tececo.com
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 => MgCO3.3H2O => 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.
June 2010
Presentation downloadable from www.tececo.com