Investigating 21st Century Cement Production in Interior Alaska Using Alaskan Resources Funded by the Fairbanks North Star Borough Project Period: April, 2009 – December, 2010 Grant Number: 012409 Primary Investigator: GH Cole Sonafrank Assistant Director of Research, CCHRC CCHRC - www.cchrc.org, P.O. Box 82489, Fairbanks, AK 99708, 907-457-3454 Abstract High performance geopolymer cements are used commercially elsewhere in the world due to superior performance to portland cement. These cements are stronger,1 fireproof,2 and waterproof.3,19 They bond strongly to most materials,4 do not appreciably expand or contract,5 are foamable,6 and resistant to salts, acids and alkalis.7,8,18 They also require less energy to make9,10,20 and are more environmentally benign.11 Additionally, geopolymer cement can be produced in ways that make it useful for addressing a range of everyday and extreme challenges. Through this grant and related work, CCHRC has investigated the potential for producing geopolymer cements using local materials and making products for the Alaskan marketplace. Based on this review, CCHRC is optimistic about the chance for a commercially viable enterprise to develop. Compounding our optimism is the potential for a new geopolymer industry to create local jobs and economic opportunities, wisely use Alaskan resources such as fly ash and mine tailings, make products that help address the extreme challenges of our geographical setting, and significantly reduce CO emissions 2 associated with cement manufacturing. Geopolymers require 30-60% less energy to make9,10 and release about 80% less carbon dioxide into the atmosphere.11 Unlike portland cement, which requires a huge plant costing upwards of $150 million to manufacture, geopolymer cement production requires only a concrete batch plant costing between $50,000 and $200,000. In part, this is because the source materials for geopolymers are by-products that have already gone through combustion in a power plant, or milling in a mine, which are processes analogous to transforming limestone into portland cement clinker. Five coal-fired electrical power generation plants12,13 in Interior Alaska are currently producing more than 100,000 tons of ash per year. The Fort Knox gold mine has more than 200 million tons of finely milled tailings accumulated in their retention pond.14 These pre-processed materials can be used to locally manufacture geopolymer cement, concrete and derivative products. This project has demonstrated that fly ash from GVEA’s Healy 1 power plant and from Aurora Energy’s Chena power plant both work as the sole active alumina-silicate source for producing geopolymer cements. Fort Knox mine tailings are demonstrated to be a useful filler material and further experimentation may confirm their potential as an active component. The cost of producing geopolymer cement-based concrete in Fairbanks, Alaska, is approximately the same as the cost of producing portland cement-based concrete in Fairbanks at current material prices. The material cost for both is approximately $84 per cubic yard. The processing equipment and costs are the same. The higher the concrete’s performance specifications are set, the more cost advantageous using geopolymer cement becomes. This project has moved Fairbanks significantly closer to being ready to utilize local resources presently wasted to commercially manufacture geopolymer cements, concrete and derivative products on an economically competitive basis. CCHRC - www.cchrc.org, P.O. Box 82489, Fairbanks, AK 99708, 907-457-3454 2 of 114 Contents Abstract 2 Contents 3 Project Description 4 Accomplishments 5 Next Steps 9 Appendices 13 A.Footnotes 13 B.Producing Geopolymers in Interior Alaska 15 C.Alaskan Geopolymer Costs 65 D.Interior Alaska’s Geopolymer Potential 87 E.A Comparison of Portland and Geopolymer Cement Costs 103 F.Elemental Composition and Particle Size Distribution Analysis of Alaskan Raw Materials 105 G.Usibelli Coal Produces More Than Power, Pollution and Profit 109 CCHRC - www.cchrc.org, P.O. Box 82489, Fairbanks, AK 99708, 907-457-3454 3 of 114 Project Description This project was undertaken to investigate and foster local manufacturing of cement and cement products using locally available resources. The cements investigated are known as “geopolymers” or “alkali-activated alumina-silicates.” The fundamental chemistry and molecular structure of geopolymers are significantly different from portland cement. Geopolymers are relatively new cements that have been developed and are commercially available elsewhere in the world. Geopolymers are substantially superior to portland cement in all performance measurements. These cements are stronger,1 fireproof,2 and waterproof.3,19 They bond strongly to most materials,4 do not appreciably expand or contract,5 are foamable,6 and resistant to salts, acids and alkalis,7,8,18 They also require less energy to make9,10and are more environmentally benign.11 Concrete is, and will continue to be, a vital component of the infrastructure upon which modern economies are based. About three tons per human on earth are manufactured every year and global demand continues to increase.15,16 Concrete is made from locally available sand and gravel bound together by cement. For the last century the cement used has been predominantly portland cement made from limestone. The production of every ton of portland cement releases about a ton of carbon dioxide into the atmosphere11 and consumes the energy equivalent of 450 lbs of coal.9,10,17,20 All of the concrete in Alaska is made using portland cement imported from Outside, mostly from Korea. Imported portland cement is costly and has bearing on project economics for which cement is required. This is especially prescient in remote areas and large projects. Funded by the Fairbanks North Star Borough, this project was built upon CCHRC’s substantial investment researching and experimenting with modern cements over the past three years. This early research determined that the performance characteristics of these cements make them well-suited for creating high-performance products which could resolve many existing housing problems in cold climates, while reducing environmental impacts. CCHRC has focused on investigating how geopolymers can be made using raw materials readily available in Alaska, including ash from coal-fired electrical generation plants, mine tailings and naturally occurring materials such as clay and glacial silt. CCHRC’s base of knowledge and empirical test results provided a strong foundation for this project. Central to CCHRC’s mission and strategic plan is to work with private manufacturing companies to help develop superior products. This project established and provided the foundation for expanding the collaborative relationships between the University of Alaska Fairbanks (UAF), non-profit, for-profit, and public corporations that will be necessary to accomplish the work necessary to bring locally produced geopolymer cement products to a willing market. CCHRC - www.cchrc.org, P.O. Box 82489, Fairbanks, AK 99708, 907-457-3454 4 of 114 Accomplishments Development of presentations: Two PowerPoint presentations were developed and used to introduce the potential for producing geopolymer cement and cement products in Fairbanks. The first, “Producing Geopolymers in Interior Alaska” (Appendix A), is intended for a general audience. The second, “Alaskan Geopolymer Costs” (Appendix B), is intended for those interested primarily in the economic competitiveness of geopolymer cement compared to portland cement. Development of prototype mix designs: Through experimentation, several successful mix designs have been developed using fly ash from GVEA’s Healy 1 power plant in Healy and Aurora Energy’s Chena power plant in Fairbanks. Some of the most successful mixes also include tailings from the Fort Knox gold mine. These mixes use sodium or potassium hydroxide and sodium silicate as the alkali-activator and small amounts of other additives commonly used in cements such as superplasticizers and set retarders. Analysis of locally available raw materials which are potentially suitable: Whether or not a raw material is suitable for making geopolymer cement depends primarily upon three factors: it’s silica content; it’s alumina content; and the reactivity of the two. In simplified and practical terms, for a given alumina-silicate material, this boils down to answering the questions: 1) does it contain a significant amount of alumina?; and 2) are the particles small enough, or the molecular structure amorphous enough, that they are partially soluble in a strongly alkaline solution? If the answer to both is yes, then the material may be suitable as a primary component for making geopolymer cement. If the answer to only one is yes and the other no, then the material may still be useful, but not without some additional alumina-silicate source. To determine their chemical makeup, X-ray fluorescence (XRF) analysis was conducted by Ken Severin at UAF’s Advanced Instrumentation Laboratory on several fine particulate alumina-silicate materials readily available in the Interior. These included fly ash from the Healy 1, Aurora and UAF power plants, Fort Knox and Pogo mine tailings, and three sources of silt. Analysis was also done on samples of some naturally occurring clay from Healy, Hinkley Gulch, Livengood, Murphy Dome, Silver Fox and the Taylor Highway provided courtesy of chemist and potter David Stannard. Metakaolin (calcined kaolin clay), which is most commonly used for producing geopolymers in the laboratory, was included in the analysis for reference. The graphical representation of the XRF results is provided in Appendix E. CCHRC - www.cchrc.org, P.O. Box 82489, Fairbanks, AK 99708, 907-457-3454 5 of 114 Additionally, UAF’s Advanced Instrumentation Laboratory performed a particle size distribution analysis on the same set of samples. A graphical representation of the results is provided in Appendix E. Experimental and analysis results indicate that all of these materials are potentially useful for producing geopolymer cements. Since CCHRC’s efforts to date have focused upon the most readily available materials, the natural clay that would require quarry development have not yet been investigated. Of the rest, only the fly ashes have been demonstrated to work as the sole active alumina-silicate source for geopolymer cement production. The Fort Knox mine tailings have proven to be a useful filler material and further experimentation may determine their potential as an active component. Likewise, Chena river mud, which has the finest particle size of the local silts sampled, may be useful either for making geopolymers that require some heat to cure, or after calcining to increase their reactivity. Calcining, in this case, involves heating the silt in a kiln to approximately 1400°F for about 30 minutes. Collaboration with Aurora Energy, LLC: Aurora Energy, LLC, owned by Usibelli Coal Mine, Inc., owns and operates the coal-fired electrical power generation plant located on the Chena River in downtown Fairbanks. Like all coal-burning companies, Aurora Energy is facing a significant increase to their operating costs. The US Environmental Protection Agency (EPA) will likely soon reclassify fly ash as a hazardous waste. This will mean that instead of being cheaply disposed of as a benign fill material, the ash will be isolated in a hazardous waste disposal facility. Therefore, Aurora Energy, Usibelli and other coal providers and users are seeking more economically beneficial alternatives. The most common use of fly ash around the world is as a supplemental cementitious material (SCM), added to portland cement and/or concrete to improve its physical properties and decrease cost. This use of fly ash from Alaskan coal is more complicated than using ash from most of the rest of the United States due to its higher calcium content. Aurora Energy’s fly ash, and ash from similar power plants, has the additional problem of containing too much un-burnt carbon to meet the standards required for use in portland cement mixes. The excess carbon interferes with the chemical admixtures, particularly for air entrainment necessary for freeze-thaw endurance. This degrades the performance of the concrete. In areas with denser populations and greater volumes of fly ash, the removal and recycling of carbon from fly ash is economically viable. That does not appear to be the case here in Alaska. These issues, combined with a commitment to economic development in their local community, have led the Usibelli and Aurora Energy management teams to take an active leadership role in investigating the potentials for using fly ash for the production CCHRC - www.cchrc.org, P.O. Box 82489, Fairbanks, AK 99708, 907-457-3454 6 of 114 of geopolymer cement. As a direct result of this FNSB-funded project, Aurora Energy is working closely with CCHRC to continue this investigation with the goal of involving additional private companies this spring and summer. CCHRC is grateful to and encouraged by Aurora Energy and most especially CEO Buki Wright’s enthusiastic interest and funding support. Collaboration with UAF School of Management: Associate professor Jim Collins, UAF School of Management Director of Entrepreneurship, has taken an interest in this project and begun involving some of his students in working on the economic feasibility and business-planning aspects. This project provides students with an excellent opportunity to leverage their academic study and exercises into real-world results. CCHRC is pleased and grateful to have the opportunity to collaborate with these students and for Dr. Collins’ interest and mentorship. Collaboration with Small Businesses in Fairbanks & North Pole: A growing number of local cement-related business owners and managers are expressing interest in participating directly in CCHRC’s efforts to develop the commercial applications of geopolymer cements and concretes. These businesses presently include Stonecastle Masonry, Fairweather Masonry, MAPPA Test Lab, and Fairbanks Precast & Rebar. One of the top 20 in the 2010 Arctic Innovation Competition: Out of more than 200 entries in the UAF School of Management 2010 Arctic Innovation Competition, CCHRC’s presentation (given by Ty Keltner) on the potential for local geopolymer development was selected as one of the top 20. The final four projects were notably further along in the process of establishing a specific business. CCHRC’s involvement in the competition helped establish connections with individuals contributing suggestions and expressing interest in working with us in the future. These included Jim Collins in the School of Management and Shiva Hullavarad in the Advanced Materials Group of the UAF Institute of Northern Engineering. Collection and organization of 2.5GB of relevant literature: CCHRC staff have collected, organized and partially reviewed more than 2.5 GB of text on the alternatives to portland cement. That currently amounts to 2,049 files in 161 folders and seven mind-maps, including over 600 research papers. Plus seven text books on geopolymer cements. Although it is outside the scope of this project, the organization of this information has been done in a manner which will facilitate references, abstracts and CCHRC’s notes being made publically available on the Internet without copyright infringement. It is our hope that this extensive and on-going literature CCHRC - www.cchrc.org, P.O. Box 82489, Fairbanks, AK 99708, 907-457-3454 7 of 114 search will help and encourage UAF graduate students to undertake master’s projects in support of local geopolymer production and use. Development of a geopolymer research proposal to the National Science Foundation: In 2009, as part of CCHRC’s on-going efforts to secure funding to expand and accelerate work toward the local geopolymer production, a proposal was developed and submitted to the National Science Foundation (NSF) Structural Materials and Mechanics program for $498,000, to be given over three years. Unfortunately, CCHRC’s proposal was not funded. That program did fund four other geopolymer projects totaling $800k. CCHRC is presently working with faculty from the UAF Geological Engineering Program to revise, update and improve our previous proposal for re-submission to this year’s funding cycle to the same NSF program. Preparatory work toward proposals to other public and private funding sources & collaborators: This project has accomplished much of the preparatory work necessary for developing credible proposals to public agencies and private corporations likely to have a serious interest in its goals. These include the US Army Corp of Engineers, the Alaska Railroad Corporation and the Alaska Department of Transportation, among many others. CCHRC - www.cchrc.org, P.O. Box 82489, Fairbanks, AK 99708, 907-457-3454 8 of 114 Next Steps Toward Geopolymer Production Submit proposals to public and private funding sources and collaborators: • Since the potential impacts of using geopolymer-based concretes for infrastructure such as dams, dikes, sea walls and armor blocks is so significant, the US Army Corps of Engineers should be one of the next agencies contacted. • Presentations need to be given to the Alaska Railroad Corporation and the Alaska Department of Transportation to determine what work they would consider funding and the potential scope for geopolymer use in Alaska’s transportation infrastructure market. • Similarly, presentations need to be given to private corporations such as Doyon, Ltd, NANA Regional Corporation, Eklutna, Inc. and others that are involved in large scale construction projects. • Mining companies including Kinross (Fort Knox), Sumitomo (Pogo), Teck Cominco (Red Dog), Coeur Alaska (Kensington), The Pebble Partnership and Northern Dynasty Minerals (Pebble), need to be contacted regarding the potential for using mine tailings to produce geopolymers as well as the potential uses of geopolymers for at mines. • Once the economic feasibility and Alaskan market potential have been sufficiently analyzed and collaborations with private corporations established, a proposal to the Alaska Industrial Development and Export Authority to facilitate capitalization would be in order. Further economic feasibility analysis and business planning: • For local geopolymer bulk concrete production; • For local concrete railroad sleeper production; • For local production of other specific concrete products. Development and testing of geopolymer concrete mix designs: • Using the cement and mortar mix designs developed thus far, produce concrete using a variety of locally available aggregates and test their performance characteristics. Further optimization of the geopolymer mix designs will be an on-going process. • Continue working with local companies such as HC Redi-Mix and Alaska Precasters to ensure that the geopolymer concrete will be of commercial interest. This work will be accomplished by CCHRC this spring in collaboration with and funded by Aurora Energy. Investigation of other locally available alumina-silicate sources: CCHRC - www.cchrc.org, P.O. Box 82489, Fairbanks, AK 99708, 907-457-3454 9 of 114 • Healy clay is worthy of special attention since it is already being removed as part of the overburden in the Usibelli Coal Mine operations. From geological investigations done in the past by the UAF Mineral Industry Research Laboratory, Healy clay is known to be high-quality kaolin clay. It may require little or no processing to be useful in geopolymer cement production. • UAF’s Silver Fox clay, Tanana Valley loess and silts may decrease costs and open up possibilities for remote village geopolymer production. Investigation of the alkali-activator sources: • Gather more specific information regarding the possibilities for importing industrial quantities of dry sodium hydroxide and sodium (meta)silicate. • Potential sources of alkalis to use instead of importing sodium or potassium hydroxide have not yet been investigated, but there are no obvious local alternatives. The predominant method for producing sodium hydroxide is through the electrolysis of salt from sea water. Thus, Alaskan production of sodium hydroxide could become economical only if the cost of electricity decreased dramatically as a result of, for example, a large hydro-electric dam being built. How the local production of geopolymer concrete would impact the engineering and cost of constructing such a dam is worthy of further investigation. Preliminary product prototyping: • Railroad sleepers • Paving blocks • Pervious pavements • Refractory bricks • Radiant floor slabs • Floor, wall and ceiling tiles • Counter tops • Exterior wall sheathings, e.g., simulated rock, simulated wood, etc. • Roofing shingles • Retaining wall blocks • Foamed/aerated insulating blocks • Whatever local precasters want to try Concrete and composite reinforcement evaluation: • The performance characteristics of various reinforcing materials, when used in locally produced geopolymer concrete and composites, needs to be tested. This includes standard steel rebar, basalt rebar, chopped stainless steel wire, as well as polypropylene, nylon, glass, basalt, and refractory ceramic fibers. CCHRC - www.cchrc.org, P.O. Box 82489, Fairbanks, AK 99708, 907-457-3454 10 of 114