The Untapped Potential of Fly Ash - Rishit Dalal, Jaycee

In an exclusive interview with CemWeek, Rishit Dalal, Director of Projects and International Business at Jaycee, shares his insights on the global fly ash market, from current challenges preventing higher utilization rates to the green potential of the coal combustion by-product

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According to official statistics, India produced 196 million tons of fly ash in 2017-18, but only 67% was gainfully utilized. What do you think are the current and upcoming challenges preventing higher fly ash utilization?

India is predominantly a coal-power driven economy and fly ash (as a by-product of coal combustion) will remain in abundance for the foreseeable future. Despite this, the overall utilization level of fly ash in the country has been below par, because of various challenges. First, there is a demand-supply mismatch wherein many power plants are located far from consumption centers and ports, making it logistically uneconomical to transport/ export fly ash to consumers. Second, the government has issued various notifications on fly ash utilization - directing power plants to support and promote ash-based industries, subsidize transportation within a specified radius, mandating various government agencies to increase ash usage, etc. but implementation has been weak resulting in limited impact. Moreover, there are no incentives/ subsidies on fly ash utilization or exports, which constrains competitiveness. Third, the fly ash industry is highly fragmented and unorganized, with only few players investing capital and focusing on value-added, quality products that can drive large-scale utilization. This is exacerbated by the fact that coal power plants usually provide only short-term contracts for demand-linked price elasticity. This approach deters serious, long-term investments due to lack of supply security. All of these factors have prevented higher fly ash utilization, and a concerted effort by industry participants, including the government, is needed to create and execute a robust ash utilization strategy.

How do you assess the environmental impact of unutilized fly ash?

Unutilized fly ash is dumped into ÔÇÿash pondsÔÇÖ, which play havoc with the environment. They result in significant air quality degradation and toxicity. For example, unutilized fly ash contributed to 37% PM10 and 26% PM2.5 in Delhi ÔÇô the capital of India. This can cause respiratory diseases, cancer and long-term health hazards such as birth defects and nervous system disorders. Moreover, ash ponds take away land from productive uses, causing direct economic losses. Heavy metal leaching into the soil prevents agriculture, contaminates ground water and affects flora and fauna. Disposal of unutilized fly ash thus has serious economic, environmental and social consequences that must not be ignored.

What are India's main advantages regarding fly ash production as compared to other producing markets?

Unlike other ash-producing countries where coal power plants are winding down to comply with carbon emission regulations, India will predominantly have coal power for the next few decades - assuring secure, stable and abundant fly ash availability for consumers. The majority of the power plants in India run on single-source, domestic Indian coal with a high ash content of 30-35%. This produces consistent quality fly ash with superior chemical properties (Class-F, siliceous), low LOI < 1% and stable color. With classification, the fineness can be controlled for various applications. While domestic consumption is dependent on proximity of power plants to consumers (mainly cement, concrete, bricks and blocks), India also has coastal power plants near major ports, from where exports can be done in containers, break bulk and bulk economically.

Can India turn fly ash into an important export asset? How?

India currently exports 800,000-900,000 metric tons per year of fly ash, mainly to Bangladesh and Middle East, with smaller volumes going into Asia-Pacific and Africa. As a proportion of ash produced, these volumes are insignificant and there is large untapped potential. Fly ash exports rely on three main elements - quality, supply chain and price. Power plants with a stable coal source (preferably single-source, domestic Indian coal) produce consistent quality ash with low LOI < 1% and stable color. With classification, this ash becomes superior to all international standards like ASTM C618 Class-F, EN 450 Category S/N, AS/NZS 3582 and GB/T 1596. The right supply chain must be determined for each market - be it containers, break-bulk or bulk. And if the power plant is close to port, the pricing can be made globally competitive for exports to happen in large volumes. Indian power plants typically do not invest in ash beneficiation nor do they export directly, so buyers need to work with ash exporters that own processing and export facilities. However, it is critical to conduct thorough due diligence of the exporter - check supply security (long-term agreement with power plant), identify coal source to analyze ash quality, consistency and color, inspect the ash processing and export facilities, check quality certifications like CE, ISO, etc. and importantly, verify the track record and credibility of the organization. Finally, to give a strong impetus to exports, the Government of India must include fly-Ash-based products in existing export promotion schemes such as MEIS, Interest Equalization Scheme, Market Access Initiatives and MSME schemes, which is lacking at present.

What else can the Indian government do to encourage fly ash use not only across the cement industry, but in other sectors as well?

In September 2018, the Prime Minister's Office in India has asked all government agencies to multiply fly ash usage by 10 times in a time-bound manner to ensure clean air and minimize adverse impact on the environment. Fly ash bricks are being made mandatory in all government construction, while fly ash use is being mandated in all highways, roads and flyover projects as well as government initiatives such as smart cities, etc. A complete ban of clay bricks within a 300 km radius of power plants is also being considered to promote fly ash bricks. Furthermore, the Ministry of Power has launched a mobile application named ÔÇÿAshtrackÔÇÖ to monitor ash generation and utilization across India. The government has also seeded research institutes like Advanced Materials and Process Research Institute, National Metallurgical Laboratory, National Environmental Engineering Research Institute and National Council for Cement and Building Materials, to develop new-age applications of fly ash. There has been significant work done on cement-free green concrete, high volume fly ash concrete, coating materials, lightweight aggregates, furniture from hybrid composite materials, ceramics, geopolymers, insulation materials, zeolites and agricultural applications. However, the government must accelerate commercialization of the research work by providing special incentives to fly-ash-based industries, and promoting them through ÔÇÿMake-In-IndiaÔÇÖ and ÔÇÿStart-up IndiaÔÇÖ initiatives. Exports of fly-ash-based products must also be incentivized through inclusion in various export promotion schemes, as it provides an additional avenue for utilization and brings in valuable foreign exchange for the country.

Fly ash use can implicate longer concrete setting times. Availability of fly ash is also a problem in many regions. How do you think these factors can prove detrimental to the broader use of fly ash in the global construction sector?

Fly ash consists of small, hard, spherical particles rich in silica and alumina. It partially replaces cement in concrete and reacts with free lime to form an additional durable binder named calcium silicate hydrate. The spherical particles have a ÔÇÿball-bearingÔÇÖ effect, which increases workability/ flowability of concrete and allows concrete to be produced using less water, with long-term strength gain. Optimization of concrete mix design can help users reduce overall cost of concrete (and construction) using fly ash. The setting time can be controlled by adjusting the water-cement ratio as well as admixture dosage, and is not a major detriment. Usage of fly ash also depends on availability from logistically-economical sources. However, fly ash usage is mandated in certain projects purely for its technical advantages, and cost is not a consideration even if it is more expensive from cement. To overcome the problem of domestic availability, fly ash can be imported from other sources/countries with cost-optimized supply chains. New technologies are also available to reclaim pond ash for use in concrete, and fly ash is expected to have global demand for the foreseeable future.

What role can fly ash play in rendering the concrete-making process greener?

Fly ash is a by-product of coal combustion, and does not require additional energy-intensive processes. It partially replaces cement in concrete, thus saving 0.7-1 ton of CO2 per ton of fly ash. According to research, one ton of fly ash used saves 4 million Btu of energy and 90 gallons of water. It also reduces water demand in concrete due to its spherical shape. Furthermore, fly ash significantly increases the durability of concrete, increases life of structures and reduces maintenance. Thus, it is a very important part of green building/ sustainable construction and is accredited by the US Green Building Council for the LEED certification program.

What are the main factors boosting global fly ash consumption? And what holds it back?

Since the construction of Hoover Dam in the 1930's, fly ash has been an integral part of the global construction industry. Major markets such as North America, Europe, Australia, China and India use fly ash in most cement and concrete for technical and commercial reasons. Fly ash being a recycled material, is more economical than cement and directly replaces 20-30% (and even more) cement in concrete, thus saving cost. Fly ash also provides increased long-term strength, durability, workability and reduced heat of hydration, alkali silica reaction, as well as chemical attacks. It reduces water-demand in concrete, and in parallel, increases life of structure. While the technical and commercial advantages of fly ash will drive global consumption, substitutes like ground granulated blast furnace slag will also impact demand in some markets. Moreover, lower fly ash generation due to winding down of coal power plants in North America, Europe and Australia means that fly ash will either have to be reclaimed from ash ponds, or imported from countries like India where it is available in abundance. Robust, cost-efficient global supply chains will have to be developed to fill the need gap in large markets.

How can transportation issues impact fly ash trade?

Being a recycled product, the intrinsic value of fly ash is low and transportation typically constitutes 30-80% of the landed cost of fly ash in domestic as well as export markets. Fly ash transportation over long distances makes it economically unviable, unless specified for technical reasons. Therefore, consumers prefer fly ash from the nearest coal power plant to keep transportation costs in check. As far as exports are concerned, containerized cargo (with jumbo bags) is economical only for some destinations, whereas we need to look at larger break-bulk or bulk shipments for destinations with sailing time of more than 15-20 days. The right mode of packing and transportation is critical in making fly ash trade economically viable.

Scientists from the Nanyang Technological University, Singapore, managed to launch a proof-of-concept for a 3D-printed bathroom using fly ash in less than a day. How can fly ash help boost innovation in the building materials sector?

Fly ash is a unique material, and people are developing newer, innovative applications in the building materials industry using it. Since fly ash plays an important role in reducing CO2 emissions, companies are working on developing ÔÇÿGeopolymer CementÔÇÖ using fly ash and activators, which can completely replace Portland cement in some applications. There are other companies working on manufacturing bricks, blocks, pavers, pipes and tiles with a very high proportion of fly ash (up to 95%), creating light-weight aggregates from fly ash, developing specialized fillers for plaster and rubber products, creating hybrid composite materials using fly ash to substitute wood, and also extracting rare earth elements from fly ash. The value-added fly ash products space is looking exciting and we will see some interesting innovations in the time to come.

This interview originally appeared on CemWeek Magazine #51