TecEco Technology and Geopolymers

1. Can we create more polymeric non hydration species using Ca-Mg cements? TecEco Technology and Geopolymers It is time to deploy new technology materials like geopolymers and TecEco cement binders that offer waste utilisation, emissions reduction, capture and sequestration. Sustainability 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. TecEco Binder Systems and Geopolymer • Geopolymers and TecEco binders have much in common. • Both are sustainable materials with common deployment issues e.g. • Response to the reality of carbon taxes. • Lobby groups and competition product associations e.g. • Portland cement industry putting out information to diffuse and confuse regarding geopolymer and TecEco technology. • Lobby groups having a disproportionate say on government committees etc. • Research development and deployment issues. • Energy issues. • Government policy issues. • Development of standards and codes of practice? • Can we learn from each other? Can we help each other? • There are also features of tec-cement chemistry that invoke hydrolysis and more polymeric reactions. There are definitely benefits to co-operation between the two emerging technologies e.g. EU research funding.

3. The Problem – A Planet in Crisis TecEco are in the BIGGEST Business on the Planet - Solving Sustainability Problems Economically A Planet in Crisis?

4. A Demographic Explosion ? Undeveloped Countries Developed Countries Global population, consumption per capita and our footprint on the planet is exploding.

5. Atmospheric Carbon Dioxide

6. Global Temperature Anomaly

7. The Techno-Process 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. Earth Systems Atmospheric composition, climate, land cover, marine ecosystems, pollution, coastal zones, freshwater systems, salinity and global biological diversity have all been substantially affected. Detrimental affects on earth systems Move 500-600 billion tonnesUse some 50 billion tonnes

8. 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

9. 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 2.1 tonnes per person per annum TecEco Pty. Ltd. And the geopolymer industry both have important technologies for improvement in sustainability and properties

10. 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/brochures/embodied/embodied.htm (last accessed 07 March 2000)

11. 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/brochures/embodied/embodied.htm (last accessed 07 March 2000)

12. 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% of global anthropogenic CO2. • Pearce, F., "The Concrete Jungle Overheats", New Scientist, 19 July, No 2097, 1997 (page 14). CO2 CO2 The article by Fred Pearce was based on a 1994 article by Joseph Davidovits of the Geopolymer Institute titled “Global Warming Impacts on the Cement and Aggregates Industries.” World Resources Review, pages 263-278, volume 6, number 2.

13. Cement Production = Carbon Dioxide Emissions Between geopolymers, tec, eco and enviro-cements we can provide a viable much more sustainable alternative.

14. Sustainability • Sustainability is a direction not a destination. • Our approach should be holistically balanced and involve • Everybody, every process, every day. + + Geopolymers + TecEco Cements= Low Emissions ProductionMineral Sequestration + Waste utilization Emissions reductionthrough efficiency andconversion to non fossil fuels Geological Seques-tration Common Contributions?

15. Materials Affect Underlying Molecular Flows Recycle Waste only what is biodegradable or can be re-assimilated Take only renewables → Manipulate → Make→ Use → ReuseRe-make e.g. heavy metals, cfc’s, c=halogen compounds and CO2 [ ←Materials→ ] [← Underlying molecular flows →] Materials control: How much and what we have to take to manufacture the materials we use.How long materials remain of utility, whether they are easily recycled and how andwhat form they are in when we eventually throw them “away”. What we take from the environment around us, how we manipulate and make materials out of what we take and what we waste result in underlying molecular flows that affect earth systems. Problems in the global commons today include heavy metals, halogen carbon double bond compounds, CFC’s too much CO2 etc.

16. Innovative New Materials - the Key to Sustainability The choice of materials in construction controls emissions, lifetime and embodied energies, user comfort, use of recycled wastes, durability, recyclability and the properties of wastes returned to the bio-geo-sphere. There is no such place as “away”, only a global commons

17. 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 New Technical Paradigms are required that deliver sustainability. (TecEco and geopolymers.) 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

18. Huge Potential for Sustainable Materials in the Built Environment C C Waste C Waste C C • The built environment is made of materials and is our footprint on earth. • It comprises buildings and infrastructure. • Construction 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. • Reducing emissions and other impacts during manufacture. • Including carbon in materials so they become carbon sinks (eco-cements). • including wastes fortheir physical properties aswell as chemical compositionso they become resources.

19. 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

20. TecEco Kiln Technology • Tec-Kiln technology will be the first non fossil fuel industrial process. • variable energy input. • Made from geopolymers. • Suitable for the manufacture of MgO, CaO and metakaolin. Eventually Portland cement. • Grinds and calcines at the same time. • Runs 25% to 30% more efficiency. • Theoretically capable of producing much more reactive MgO as well as metakaolin and other input materials for geopolymers.

21. TecEco Kiln Technology • Captures CO2 for bottling and sale. • To the oil industry (geological sequestration). • Coca Cola? • 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 plan to use geopolymer materials for the kiln capable of withstanding high temperatures.

22. Drivers for TecEco & Geopolymer Technology Government Influence Carbon Taxes Provision of Research Funds Environmental education Consumer PullEnvironmental sentimentFear of climate changeCostTechnical advantagesCompetition Huge Existing Markets Cement >2 billion tonnes. New markets e.g. Bingham mixtures for robots, kilns, fireproof materials etc. Producer PushThe opportunity cost of compliant waste disposalProfitability and cost recoveryTechnical meritResource issuesRoboticsResearch objectives The way forward is through solving problems in niche markets and delivering sustainability.

23. TecEco Cement Concretes More information at www.tececo.com

24. TecEco Cements SUSTAINABILITY HYDRAULIC CEMENT + or - POZZOLAN Hydration of the various components of a hydraulic cement such as Portland cement for strength. Note that geopolymers are esp. included Reaction of alkali with pozzolans (e.g. lime with fly ash.) for sustainability, durability and strength. TECECO CEMENTS DURABILITY STRENGTH MAGNESIA Hydration of magnesia => brucite for strength, workability, dimensional stability and durability. In Eco-cements carbonation of brucite => nesquehonite, lansfordite and an amorphous phase for sustainability.

25. The Magnesium Thermodynamic Cycle

26. 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 voids:paste 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 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 (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.

27. 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, consuming water and concentrating alkalis 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.

28. Strength with Blend & Porosity Tec-cement concretes High Porosity Eco-cement concretes Enviro-cement concretes High Magnesia High PC Tec – cement concretes have more polymeric species because they are much more alkaline during the early plastic phase. STRENGTH ON ARBITARY SCALE 1-100

29. 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 raise the early Ph. • Increasing non hydraulic strength giving reactions • 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

30. Tec-Cements & Geopolymers In the presence of water magnesium does not appear to be an important network former in silicate structures including geopolymers at room temperature and this is probably because of it’s high affinity for water which it seems to retain even when it carbonates. There are however other intriguing ramifications of adding reactive MgO. More information at www.tececo.com

31. The Form of MgO - 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 water based binder systems.

32. The Form of MgO - 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 in a hydraulic binder (Ramachandran V. S., Concrete Science, Heydon & Son Ltd. 1981, p 358-360 )

33. Tec-Cement Concrete Strength Gain Curve • 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. We have observed this sort of curve in over 300 cubic meters of concrete now

34. Tec-Cement Reactions • MgO + H2O => Mg(OH)2.nH2O - water consumption resulting in greater density and higher alkalinity. • Higher alkalinity => more reactions involving silica & alumina. • Mg(OH)2.nH2O => Mg(OH)2 + H2O – slow release water for more complete hydration of PC • MgO + Al + H2O => 3MgO.Al.6H2O ??? – equivalent to flash set?? • MgO + SO4-- => various Mg oxy sulfates ?? – yes but more likely ettringite reaction consumes SO4-- first. • MgO + SiO2 => MSH ?? Yes but high alkalinity required. Strength?? We think the reactions are relatively independent of PC reactions

35. Non hydration Reactions in Tec-Cement Concretes? • MgO + H2O => Mg(OH)2.nH2O - water consumption • Increases density. • Raises the alkalinity during the early plastic stage. • Better pozzolanic reactions, surface hydrolysis and re-bonding as well as the formation of more polymeric not necessarily hydraulic species. • Resulting mineralization more similar to Roman cement concretes that contained more Mg and more polymeric species.

36. Tec-Cement pH Curves

37. Conjecture • Why does Mg keep turning up in discussion of ancient mineral systems (Egyptians, Mesopotamians and Romans)?? • Maybe sepiolite (polygorskite with Al?) are carrier minerals that break down as the alkalinity rises delivering soluble and mobile SiO2 and Al2O3 for reactions forming more polymeric minerals. This idea emerged over too many drinks with Herbert Baier of PCI (part of Degussa) on the 29th June in Saint Quentin, France. It’s conjecture, interesting and not completely daft.

38. Role of Mg++ in Geopolymerism??! • Mg4Si6O15(OH)2.6H2O (sepiolite)+ clay + sodium or potassium salt => Geopolymer (Si-O-Al-O-Si ??) + brucite + more sepiolite?? • or • Sepiolite + clay + H2O + CO2 + OH- • Geopolymer + sepiolite + salt?? Sepiolite precipitates from salty alkaline waters in arid environments and was available to the Egyptians. Does explain role of Mg in Egyptian cements.

39. Strength Development in Tec-Cements. • Reactive magnesia requires considerable water to hydrate resulting in: • A significantly lower voids/paste ratio i.e. denser, less permeable concrete. • 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? Could the role of added reactive magnesia be to consume water like the ettringite reaction in PC concretes. This property could be useful with geopolymers to overcome the viscosity problem.

40. Water Reduction During the Plastic Phase? Ph Water Reduction. Water is required to plasticise concrete for placement, however once placed, the less water over the amount required for hydration the better. Magnesia consumes water as it hydrates producing solid material. Less water results in increased density and concentration of alkalis- less shrinkage and cracking and improved strength and durability.

41. High Alkalinity Common to Both Hydraulic and Geopolymer Systems => Better Reactions. • For more effective reactions in hydraulic concretes like PC and in “geopolymer concretes” high alkalinity is required. • To achieve high alkalinity it is necessary to not add too much water –this results in higher viscosity. • To place concretes low viscosity is required. • Tec-cement concretes achieve high alkalinity by internal water removal. • The dichotomy between viscosity and ease of placement defines much of the current research on geopolymers and for that matter in relation to additives for PC. • Depending on the level of alkalinity reached, many of the particles of fly ash or dehydrated clay (Kandoxi) polymerise, react at the surface only (hydrolyse and re-bond) or remain as micro-aggregates.

42. Adding Reactive MgO • Portland cements stoichiometrically require around 23 -25% water for hydration yet we add approximately 45 to 50% at cement batching plants to fluidise the mix sufficiently for placement. • If it were not for the enormous consumption of water by tri calcium aluminate as it hydrates forming ettringite in the presence of gypsum, concrete would remain as a weak mush and probably never set. • 26 moles of water are consumed per mole of tri calcium aluminate to from a mole of solid ettringite. When the ettringite later reacts with remaining tri calcium aluminate to form monosulfoaluminate hydrate a further 4 moles of water are consumed. • The addition of reactive MgO achieves water removal in a similar way. • Can reactive MgO be used to get over the viscosity issue in geopolymers? • Would this be cheaper than using super plasticisers?

43. Adding Reactive MgO to Geopolymers • It is not possible to add water to geopolymers. If water were add the alkalis would be diluted, the pH would fall and the mix would not set as unlike the setting of Portland cement concretes there is no reaction that consumes water. On the contrary – water is expelled. • Reactive magnesia is a water removal tool and may be useful as an adjunct to assist with the viscosity problem. • Most people researching geopolymers seem to be trying various super, duper, hyper, blah blah plasticiser molecules to see if they can be used to fluidise the mix sufficiently. • The water removal mechanism of magnesia and its plasticising properties may be useful as a totally different approach to get over the viscosity issue. There is obviously more work to do pending funding but could it be that the best features of geopolymeric and hydraulic cements can be combined? • There are more polymeric species in Roman cements.

44. Non Newtonian Rheology It is not known how deep these layers get 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 Etc. Etc. Ca++ = 114, Mg++ = 86 picometres

45. MgO Changes Surface Charge as the Ph Rises + + + + + + + This could be the reason for the greater tensile strength displayed during the early plastic phase of tec-cement concretes. + + + Cement MgO Sand + + + + + + + + + + + Mutual Repulsion => Ph 12 ? + + + + - + + - + - Cement MgO - Sand + - + + + - - + + + Mutual Attraction

46. 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

47. 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.” (Robotics)

48. Technical Comparisons Geopolymers and Tec-Cement Concretes

49. Technical Comparisons Geopolymers and Tec-Cement Concretes (2)

50. Other Comparisons = Common Problems