DR. NICHOLAS DECRISTOFARO, SOLIDIA TECHNOLOGIES,

USA, OUTLINES THE INNOVATION THAT WILL RE-CATEGORISE CO2 AS

A CATALYST FOR PROFITABILITY AND GROWTH.

Advancing the cement industry’s carbon reduction goalsCement manufacturers have committed to reducing the CO2 emissions associated with their product, but they are often constrained by the equipment used in cement making and the standardised chemistry of ordinary Portland cement. US start-up Solidia Technologies has joined forces with leaders in industry, government and academia to industrialise an innovative technology that could reduce the environmental footprint of cement in precast concrete applications while reducing concrete production costs

and improving the performance of concrete-based building materials.

Cement and concrete production is ripe for disruption. But bringing a sustainable innovation to a market that dates back 2000 years, and whose last major product innovation was the development of Portland cement in the early 19th century, is no small order. Solidia is tasked not only with the development of a sustainable technology, but making that technology easy for the industry to adopt.

To that end, Solidia’s patented processes for producing sustainable cement and concrete use

September 2015Reprinted from World Cement

the industry’s existing infrastructure, raw materials, formulations, production methods and specifications.

Motivating a marketThe incentive to ‘reduce the clinker factor’ in cement products is two-fold. The primary motivation is to reduce the energy consumption and CO2 emissions associated with cement clinker production in rotary kilns. It is generally accepted that the production of 1 t of ordinary Portland cement (OPC) creates over 800 kg of CO2. The secondary reason is to reduce the environmental impact of industrial byproducts such as flyash, slag and silica fumes.

The strategy deployed to accomplish these goals is to replace a portion of the cement clinker used in

cement production with industrial byproducts, without detrimentally affecting the performance of the cement.

Using Solidia’s patented processes in the production of concrete does not reduce the clinker factor, per se, but rather helps make clinker production and use more palatable from the carbon footprint and energy consumption perspectives.

A new class of sustainable cement and novel CO2-curing technologySolidia has developed a new class of sustainable cement that reacts with gaseous CO2 rather than with water to form Solidia Concrete™. Produced with a non-hydraulic, lower-energy and lower-emission chemistry, Solidia Cement™ is more sustainable than ordinary Portland cement (OPC). The patented technology allows lower CO2 emissions in the cement production process and involves the use of CO2 as a curing agent in precast concrete manufacturing.

Solidia Cement is composed of a family of ‘green’, low-lime calcium silicate phases, similar, but not identical to the chemistry of OPC. As a result, it can be produced in existing cement kilns using the same raw materials that are used to make ordinary Portland cement, albeit in different proportions. Solidia Cement is produced using less limestone and at lower temperatures than are necessary for Portland cement. These factors translate into a reduction in the CO2 emissions during cement manufacturing, from 816 kg/t of OPC clinker to 570 kg/ t of Solidia Cement clinker. This difference alone is equivalent to achieving a 30% reduction in the clinker factor.

To create Solidia Concrete products, water, aggregates and Solidia Cement are mixed, formed into the desired shape and then reacted with gaseous CO2 to produce a durable binding matrix. The curing process consumes up to 300 kg of CO2 per t of cement used. The CO2 is permanently and safely stored in solid carbonate form within the concrete. This difference is equivalent to an additional 37% reduction in the clinker factor.

Overall CO2 emissions associated with the production and use of cement can be reduced by up to 70%. Benefits realised by the concrete industry include reduced materials and water usage, shorter curing times and improved product durability.

Solidia Concrete can be produced by manufacturers of traditional concretes and can be designed to address any precast concrete application. These products, which include paving stones, concrete blocks, hollow-core slabs, railroad sleepers (ties), roof tiles, and pervious concrete, match or exceed the properties and characteristics of concrete products made using OPC. Additionally, the Solidia Concrete cures in less than 24 hours, compared to the up to 28 days required for traditional concrete products to reach full strength. As water is not consumed during the CO2-curing process, it can be collected and reused, with recycle rates of 60 to 80%.

Solidia Cement™ clinker nodules

Formation of Solidia Cement™ clinker nodules

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Collaborators committed to commercialising sustainable solutionsSolidia has purposefully sought partnerships with private sector leaders committed to the commercialisation of sustainable technologies and with public sector organisations capable of validating technologies and accelerating their adoption.

A key innovation partner is Lafarge, a world leader in cement, concrete and building materials technology. “The mandate of the Lafarge Innovation Division is to provide solutions that meet the current and, more importantly, the future needs of both our customers and the end user,” said Lafarge Vice President Precast Concrete, Innovation Division, Peter Quail. “To do this, we invest heavily in R&D and team up with innovative start-up enterprises like Solidia Technologies.” Lafarge joined Solidia in 2013 to industrialise the technology and recently increased its support by signing on as an investor with a seat on its board of directors.

“Lafarge has an ongoing campaign to lower CO2 emissions through, among other variables, the exploration of cements that substitute ground limestone, slag and flyash to reduce the amount of Portland clinker in their blended cement offerings. The Solidia cement clinkering process represents a quantum leap in CO2 reduction well above these blended Portland cements.”

In April 2014, a joint group of Lafarge and Solidia scientists validated the reduced carbon footprint and commercial viability of Solidia cement during a full-scale trial at Lafarge’s Whitehall cement plant in the US. Over 5000 t of Solidia Cement was produced. The two companies are now actively collaborating to market this technology as a sustainable solution for the precast concrete sector. This cement has subsequently been used by a variety of precast concrete manufacturers in North America and Europe. Collaborative testing performed with concrete manufacturers in recent months has demonstrated both the superior quality of Solidia concrete products and their cost competitiveness in applications ranging from blocks to pavers to roof tiles.

Quail added, “As a 35-year veteran in the precast concrete industry, I see the physical characteristics and properties of this material to be a real game changer. Not only will Solidia cement result in an improved product with higher profitability for the precast concrete customer, it also represents a new paradigm with respect to sustainability.”

A critical development along the path to commercialising Solidia’s concrete technology will be delivering CO2 to the concrete curing location and managing it at that location. Solidia has joined forces with The Linde Group, a world-leading supplier of industrial gas and equipment and engineering. The collaboration includes the development, demonstration and commercialisation of Solidia’s carbon dioxide (CO2)-based concrete curing technology. Solidia and Linde are also collaborating on marketing the technology.

Supply of CO2 will be first for in-plant precast and eventually for onsite cast-in-place construction. Linde will bring CO2 supply and delivery expertise, including engineering of application-specific equipment, to contribute to this joint development. With its impressive CO2 supply infrastructure using trucks, railcars and ships for CO2 transport, its experience with CO2 production and its wide range of applications-specific knowledge, Linde is well prepared to support the roll-out of this technology.

“This project with Solidia marks an important step in expanding Linde’s CO2 supply and management capabilities,” said Dr Andreas Opfermann, Head of Clean Energy and Innovation Management at Linde.

As collaborators with a global reach and decades of technological and market knowledge, industry leaders such as Lafarge and Linde play a significant role in driving innovation to market. Linde’s expertise in gas delivery and equipment engineering enables rapid commercialisation by freeing Solidia to focus on the development of the core technology. Likewise, Solidia’s technology gives Linde access to a large, new market for CO2 that would not otherwise exist.

Solidia also recently signed a partnership agreement with CDS Group, the world’s largest supplier of precast concrete curing and drying equipment, to collaborate on the design of systems and components needed to cure concrete with CO2 instead of water. The innovations will include technological upgrades for existing curing chambers and the design and manufacture of new curing chambers to accommodate Solidia’s patented CO2-curing process.

CDS will play a key role in helping Solidia achieve its top R&D priority, which is to make it easy and profitable for concrete manufacturers to adopt its novel technology. Modifying existing chambers will minimise capital investment for Solidia’s customers. Because CDS is marketed worldwide, the company is fully conversant with the regulations that occur in countries across the globe and can provide systems that have technical and regulatory approval.

“Solidia’s technology will extend our commitment to delivering sustainable innovations to the global building materials market,” said Andrew J. Hall, President of US Operations of the UK-based CDS Group.

Public and academic partners join the effortAn impressive array of public sector organisations have also joined Solidia in the quest to characterise and commercialise its sustainable technology. Prominent among these is the US Department of Energy’s National Energy Technology Laboratory (DOE-NETL). To date, an ongoing research project has been funded with US$1.1 million from the DOE-NETL through its Carbon Storage Technology Program and US$1 million from Solidia Technologies as a cost share. DOE-NETL supports Solidia Cement-based concrete technology because of its potential to consume CO2 as it cures.

September 2015Reprinted from World Cement

The project has focused on developing an understanding of the relationships between the water use, CO2-curing time, and mechanical strength of Solidia Cement-based concrete. The research has demonstrated that Solidia Concrete can achieve full hardness in less time than traditional OPC-based concrete. In every application studied, Solidia Concrete cures in less than 24 hours. In addition, at every stage of curing, Solidia Concrete parts match or exceed the strength of comparable products made with OPC-based concrete.

DOE-NETL recently agreed to finance the project’s next stage, which will focus on demonstrating this CO2 reduction and storage capability on a prototype scale in a commercial concrete plant.

“As an alternative building material with a lower carbon footprint, Solidia Cement is an excellent example of the innovative technologies DOE’s Carbon Storage Program advances in its mission to promote solutions for reducing CO2 emissions,” stated NETL Carbon Storage Technology Manager Traci Rodosta. “We’re hopeful that the commercial success of Solidia Cement will encourage the view that CO2 has untapped value as a commodity.”

Other collaborators include the US Department of Transportation’s Federal Highway Administration (USDOT-FHWA), the US Environmental Protection Agency, Purdue University, The University of South Florida and Rutgers, the State University of New Jersey.

USDOT-FHWA supports Solidia through a Cooperative Research and Development Agreement (CRADA). This agreement governs a programme conducted at the Turner-Fairbank Highway Research Centre where the mechanical, chemical and environmental durability of Solidia Concrete has been systematically examined and confirmed vis-à-vis transportation infrastructure applications.

Research programmes at Purdue University and the University of South Florida also focus on the durability of Solidia Concrete. Purdue has characterised the behaviour of Solidia Concrete in freeze-thaw, in freeze-thaw with de-icing salts, and in sulfate environments. South Florida is assessing the corrosion of rebar and the overall performance of reinforced Solidia Concrete in a variety of simulated service conditions.

Long-term research at Rutgers, where the original generation of the Solidia Concrete technology was developed, continues to focus on the optimisation of the CO2-curing process.

ConclusionThe Cement Sustainability Initiative of the World Business Council for Sustainable Development set 2050 CO2 reduction targets for the global cement industry. Hypothetically, if the industry were to adopt Solidia’s technologies today, it could achieve those 2050 goals within three years.

The partnerships between Solidia, Lafarge, Linde, CDS, US government agencies and university laboratories marry the scientific innovation of a start-up with the market intelligence and global infrastructure of established industry leaders, and the expertise, facilities and funding available in the public and academic sectors. By developing a means of transforming CO2 into a valuable commodity for one of the world’s largest industries, the collaborations will help speed the market penetration and social impact, re-categorising CO2 as a catalyst for profitability and growth. Together, they create a sustainable pathway for the cement and concrete industry with the development of new technologies that offer cost savings and added value without burdening the industry with significant capital investments or dramatic changes in production.