John Harrison Tec Eco Pty Ltd Tasmania Australia

  • Slides: 27
Download presentation
John Harrison, Tec. Eco Pty. Ltd. , Tasmania, Australia Huge markets for magnesia in

John Harrison, Tec. Eco Pty. Ltd. , Tasmania, Australia Huge markets for magnesia in concretes and other cementitious composites Presentation downloadable from www. tececo. com

New Uses = New Markets n Demand in this industry has been static for

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

New Demand for New Forms of Mg. O n Reactive Magnesia l Mg. O calcined below say about 750 and fine ground to say <<45 micron. Engineered particle size, size range and reactivity. o. C l Including nano sizes or separate category? Focus on new uses for reactive Mg. O n Caustic Calcined Mg. O l Mg. O “light burned” at less that say 1000 o. C and ground relatively fine say <75 micron n Dead Burned Mg. O l Mg. O high temperature calcined, mostly periclase and often ground < 100 micron. n 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~CO 3 bond goes into lattice energy June 2010 Presentation downloadable from www. tececo. com

Why Reactive Mg. O? Lattice energy Periclase > Hydration energy Mg++ 3795 k. J/mol-1

Why Reactive Mg. O? Lattice energy Periclase > Hydration energy Mg++ 3795 k. J/mol-1 > 1926 k. J/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 Mg. O 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 Mg. O. Calcination at http: //www. tececo. com/technical. reactive_magnesia. php June 2010 Presentation downloadable from www. tececo. com

Deployment of new Cements n Quality issues l A narrower bell curve of properties

Deployment of new Cements n Quality issues l A narrower bell curve of properties such as reactivity and particle size is required n Price challenges l Reactive magnesia must compete with Portland cement n Environmental & bureaucratic challenges n Carbon caps or taxes will apply to emissions from the production of Mg. O After inventing our Tec, Eco and Enviro cements Tec. Eco set out to figure out new ways of making reactive Mg. O 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 Mg. O Step Process Conditions Upsides Downsides Mg. CO 3=>Mg.

Making Cheaper Better Reactive Mg. O Step Process Conditions Upsides Downsides Mg. CO 3=>Mg. O +↑CO 2 600 -750 OC Known technology Emissions, fossil fuel energy. Blight on landscapes. Step 1 of 2 Mg Silicate + ↓CO 2 => Mg Carbonate 180 o. C/150 bar Sequestration step Fossil fuel energy? Step 2 Mg Carbonate => Mg. O + ↑CO 2 650 -750 OC Calcination step Process energy + re release CO 2 Optional Step before Mg Silicate => Mg Salt (Mg. Cl 2) Various Known acid extraction Expensive As acid corrosive. Step 1 of 2 Mg Salt + ↓CO 2 => Mg Carbonate (Nequehonite? ) Room temp. Use waste. Carbon credits. Step 2 of 2 Mg Carbonate => Mg. O + ↑CO 2 650 -750 OC Calcination step Process energy + re release CO 2 Carbon neutral Tec. Eco 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 Tec. Eco Tec-Kiln - Changing the Way we Make Magnesia n The Tec-Kiln

The Tec. Eco Tec-Kiln - Changing the Way we Make Magnesia n 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. n The Tec. Eco Tec-Kiln makes no releases and is an essential part of Tec. Eco's plan to sequester massive amounts of CO 2 as man made carbonate in the built environment. n The Tec. Eco Tec-Kiln has the following features: l Operates in a closed system and therefore does not release CO 2 or other volatiles substances to the atmosphere l Can be powered by various potentially cheaper non fossil sources of energy such as intermittent solar or wind energy. l Grinds and calcines at the same time thereby running 25% to 30% more efficiently. l Produces more precisely definable product. (Secret as disclosure would give away the design) Mg. O l The CO 2 produced can be sold or re-used. l Cement made with the Tec-Kiln will be eligible for carbon offsets. Mg. CO 3 Tec-Kiln = Problems Solved = Way Forward June 2010 Presentation downloadable from www. tececo. com CO 2

Gaia Engineering Mg Carbonates Tec. Eco Tec-Kiln Industrial CO 2 Mg. O Aggregates Bitterns

Gaia Engineering Mg Carbonates Tec. Eco Tec-Kiln Industrial CO 2 Mg. O Aggregates Bitterns or Brines Tec. Eco. Cements Mg. Cl 2 Process Building waste Other waste June 2010 Tec. Eco Tec. Cements Concretes and Other Composites Built Environment Presentation downloadable from www. tececo. com

New Players re CO 2 Capture = > Building Materials l 13 th July

New Players re CO 2 Capture = > Building Materials l 13 th July 2002 – Fred Pearce in New Scientist about Tec. Eco 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. l 2008 - Calera Corporation u Brett Constance backed by Vinod Khoshla and others u Attracting considerable criticism from scientists as upsets p. H balance resulting in reduced inability of oceans to absorb H 2 O (Ken Caldiera and others) u Has so far produced the most expensive carbonate in the world l 2008 - Greensols Process (Cuff and Blake) u A fundamentally good idea stalled by lack of finance l 2009 - Newcastle Group (Eric Kennedy and Others) u Secretive June 2010 Presentation downloadable from www. tececo. com

The Kyoto Process – A Political and Economic Dilemma CO 2 is adversely affecting

The Kyoto Process – A Political and Economic Dilemma CO 2 is adversely affecting climate True Action Yes Cost $ Global Recession Survival False Cost $ Global Recession No Economic Political Social Environmental Catastrophe Money Saved $ CO 2 is adversely affecting climate Action Yes No Profit $ Economic Political Social Environmental Catastrophe 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 Tec. Eco 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

The Global Warming Problem Global Carbon Flows After: David Schimel and Lisa Dilling, National Centre for Atmospheric Research 2003 The global CO 2 budget is the balance of CO 2 transfers to and from the atmosphere. The transfers shown below represent the CO 2 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 CO 2 Using the Figures from

Net Atmospheric Increase in Terms of Billion Tonnes CO 2 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 CO 2 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 CO 2 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? n If a proportion of

How Much Man Made Carbonate to Solve Global Warming? n If a proportion of the built environment were man made carbonate, how much would we need to reverse global warming? Mg. O + H 2 O => Mg(OH)2 + CO 2 + 2 H 2 O => Mg. CO 3. 3 H 2 O 40. 31 + 18(l) => 58. 31 + 44. 01(g) + 2 X 18(l) => 138. 368 molar masses. 44. 01 parts by mass of CO 2 ~= 138. 368 parts by mass Mg. CO 3. 3 H 2 O 1 ~= 138. 368/44. 01= 3. 144 12 billion tonnes CO 2 ~= 37. 728 billion tonnes of nesquehonite or Mg. O + H 2 O => Mg(OH)2 + CO 2 + 2 H 2 O => Mg. CO 3 40. 31 + 18(l) => 58. 31 + 44. 01(g) + 2 X 18(l) => 84. 32 molar masses. CO 2 ~= Mg. CO 3 44. 01 parts by mass of CO 2 ~= 84. 32 parts by mass Mg. CO 3 1 ~= 84. 32/44. 01= 1. 9159 12 billion tonnes CO 2 ~= 22. 99 billion tonnes magnesite June 2010 Presentation downloadable from www. tececo. com

So How Much Magnesia Would be Sold? Not enough to show on graph How

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 June 2010 Presentation downloadable from www. tececo. com

Natural Sinks for Carbon This industry could profitably be involved in modifying the carbon

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/2 b 2. 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

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

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 CO 2. 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

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. 2 1. 1. 3. 1.

A Classification of Magnesium Cements - 1 1. 1. 2 1. 1. 3. 1. 2. 1 1. 2. 2 1. 3. 1 1. 3. 2 1. 3. 3 1. 4 1. 5. 1 1. 6 1. 7. 1 1. 7. 2 1. 8 1. 9 1. 10 Novacem 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) 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 CO 3 --. e. g Carbonic acid. (See also 1. 3. 1) As a base with inorganic substances delivering CO 3 --. e. g. Sodium carbonate and calcium carbonate, CO 2 or a chemical that releases CO 2. The CO 2 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 (CO 3 --. ) 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

A Classification of Magnesium Cements - 2 2. 2. 1 2. 2 2. 3 3 3. 1 4. • 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 (Note 1) In solution Mg++ complexes with water more readily than Ca ++ forming ions of the general form [Mg(H 2 O)N]2+. Mg++ can also hydroxylate forming H 3 O+ 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 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 Tec. Eco patent or for which insufficient information has been provided Complex mechano or nano composites. Note 1 Ref 2 Ref 3 Ref 4 June 2010 Mg++ has a hydration energy of 1926 k. J/mol compared to 1579 k. J/mol for Ca ++ [1, 2]. Six water molecules in octahedral coordination surround the Mg 2+ ion in a rigid first solvent shell [3]. For comparison, the exchange rate of water in the hydration shell of Ca 2+ ions is ~1000 -fold faster than for Mg 2+ 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. Pub. Med 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 Mg. O in Hydraulic Binder Systems? n Mg in solution is l strongly

Why Mg. O in Hydraulic Binder Systems? n Mg in solution is l strongly kosmotrophic => profound effects on rheology l increased surface tension reduces bleeding and thus early age plastic shrinkage. l Long term shrinkage eliminated. n Replaces free lime (Portlandite Ca(OH)2) in concretes l Free lime (Portlandite, Ca(OH)2) in concretes is too reactive. l 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 p. H control and eliminate autogenous shrinkage. n Dramatically improves durability l Lower solubility and reactivity (Eh & p. H conditions) of Brucite l 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. n.

Magnesium Compounds Mineral (or Product) Formula Partial Pressures Brucite Mg(OH)2 Brucite Hydrates Mg(OH)2. n. H 2 O Dypingite Mg 5(CO 3)4(OH)2· 5 H 2 O Hydromagnesite Giorgiosite Mg 5(CO 3)4(OH)2· 4 H 2 O Artinite Ph Hard ness Habit 10. 2 2. 5 - 3 Blocky pseudo hexagonal chrystals. Not much known! Low CO 2, H 2 O High? ? Platy or rounded rosettes High? 3. 5 Include acicular, lathlike, platy and rosette forms Mg 2(CO 3)(OH)2 • 3(H 2 O) 2. 5 Bright, white acicular sprays Magnesite Mg. CO 3 3. 9 Usually massive Barringtonite Mg. CO 3· 2 H 2 O 2. 5 Glassy blocky crystals Nesquehonite Mg. CO 3· 3 H 2 O Lansfordite Mg. CO 3· 5 H 2 O Presence H 2 O Variable? 2. 5 Acicular prismatic needles Glassy blocky crystals 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

Magnesium Carbonate Phases June 2010 Presentation downloadable from www. tececo. com

Why Brucite in Dense Concretes? n Brucite l Improves rheology (see http: //www. tececo.

Why Brucite in Dense Concretes? n Brucite l Improves rheology (see http: //www. tececo. com/technical. rheological_shrinkage. php) l Prevents shrinkage and cracking (see http: //www. tececo. com/technical. rheological_shrinkage. php) l Provides p. H and e. H control. Reduced corrosion. Stabilises CSH with pozzolanic reaction (Encouraged) l Provides early setting even with added pozzolans Pourbaix diagram steel reinforcing l Relinguishes polar bound water for more complete hydration of PC (thereby preventing autogenous shrinkage? ) Mg. O + H 2 O => Mg(OH)2 June 2010 Surface charge on magnesium oxide Presentation downloadable from www. tececo. com

Why Nesquehonite in Carbonating Binder Systems? n At 2. 09% of the crust magnesium

Why Nesquehonite in Carbonating Binder Systems? n At 2. 09% of the crust magnesium is the 8 th most abundant element n Nesquehonite l Has an ideal shape that contributes strength to the microstructure of a concrete l Forms readily at moderate and high p. H in the presence of CSH, our catalyst. (Nucleation mechanism? ) n The hydration of PC => alkalinity dramatically increasing the CO 3 -- levels that are essential for carbonation. Nesquehonite n Significant molar volume expansion. n Captures more CO 2 than Calcium 3 H 2 O + CO 3 ---- + Mg++ => Mg. CO 3· 3 H 2 O n 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

Tec. Eco Formulations n Tec-Cements (5 -20% Mg. O, 80 -95% OPC) l contain

Tec. Eco Formulations n Tec-Cements (5 -20% Mg. O, 80 -95% OPC) l 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 p. H. l Reactions with pozzolans are more affective. After much of the Portlandite has been consumed Brucite tends to control the long term p. H which is lower and due to it’s low solubility, mobility and reactivity results in greater durability. l 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. n Eco-Cements (20 -95% Mg. O, 80 -5% OPC) l 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. n Enviro-Cements (5 -15% Mg. O, 85 -95% OPC) l contain similar ratios of Mg. O and PC to eco-cements but in non permeable concretes brucite does not carbonate readily. l 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 n To avoid carbon costs and other imposts maybe the industry should consider

Conclusion n To avoid carbon costs and other imposts maybe the industry should consider making Mg. O in different way. l The industry can gain a competitive advantage by being the first to produce product without releases and utilising wastes. u Mg. Cl 2 + CO 2 => Mg. CO 3. 3 H 2 O => Mg. O +CO 2 n 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. l There must be much more focussed research into this wide array of new products as they are sold into technical markets. n Mg. O of better quality and lower price is required to compete with Portland cement. n As in the cement industry the Mg. O 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