Innovation In Cement Production Crucial To Environmental Sustainability

Innovation In Cement Production Crucial To Environmental Sustainability

In this exclusive article SA Builder delves into sustainability in cement production:

AfriSam’s value of ‘Planet’ is defined as a responsibility for the impact of its actions on the community and the environment

AfriSam’s Dudfield cement plant near Lichtenburg in the North-West province has its roots dating back to 1949 and remains a vital pillar in South Africa’s construction sector.

Vishal Aniruth, general manager at AfriSam Dudfield, notes that the plant had seen a number of production upgrades over its life-time. As importantly, it had been at the leading edge of efforts to achieve environmental sustainability.

We were one of the first plants in the country to convert from old electrostatic precipitator technology in terms of air emissions control,” Aniruth said. “This involved the installation of bag-house filter technology for kiln emissions, and allowed us to achieve compliance with the latest emissions standards.”

The Dudfield facility began as a mining operation, exploiting the shallow calcrete deposit that covers the entire 3 608 hectare mining licence. Before the plant was built, the mined limestone was shipped to the company’s kilns in Roodepoort.

Today, the quarry is a split-bench operation that opens up about 15 hectares a year. It produces annually about two million tonnes of limestone and 120 000 tons of shale for the plant from the Spring Valley quarry, located 65 km away.

Aniruth highlighted that the latest computer-based modelling techniques are used for deposit optimisation. This ensures that the mine plan generates the required quality of material for the plant. He noted that there are 65 years of proven reserves at the quarry, with further reserves at AfriSam properties at Kalkfontein and on the neighbouring farm Bethlehem.

AfriSam’s Dudfield cement operation in the North West Province was commissioned in 1965

Long experience

The cement plant itself was commissioned in 1965, with one kiln with the capacity to produce 380 000 tonnes per year. Kiln 2 followed in 1972, with an annual production capacity upgraded over time to 780 000 tons. The plant grew further in 1977, when Kiln 3 was added, augmenting capacity by another 630 000 tonnes a year. In an important market-leading innovation in 1992, Dudfield installed the country’s first cement roller press to enhance the manufacturing process and improve grinding capacity.

Continuously aligning its production capacity with market demand, AfriSam Dudfield upgraded its Kiln 3 capacity in 2003 to over a million tonnes a year. The plant currently operates only the Kiln 3 production line – a four-stage configuration with in-line pre-calciner. The kiln features indirect firing with a multi-channel burner.

Fully integrated plants

Among the key elements of current plant operations at Dudfield are two coal mills and two cement mills. Coal mill 1, constructed in 1966 with production capacity of 11 tonnes an hour, feeds the pre-calciner burner. The other unit mills coal for the main burner, and was built in 1975 with a 16 ton per hour capacity. Cement mill 1, installed in 1966, has a 49 ton per hour capacity. The second cement mill is larger, giving it double the capacity at 98 tonnes an hour.

The cement output from Dudfield is delivered as road bulk, rail bulk and bagged cement. The plant’s in-house road bulk and weighbridge facility is used to load tankers. On the rail bulk operation, a large portion of the plant’s production is railed to AfriSam depots. Clinker is also supplied to AfriSam’s Roodepoort milling facility. The packing and palletising facility produces a bagged cement product for the market.

Dudfield is one of two fully integrated AfriSam cement plants in South Africa, which together can produce 4,5 million tons of cement. The second is the Ulco plant in the Northern Cape. The company’s third plant – with annual capacity of 1,2 million tons – is in Tanzania.

The cement output from Dudfield is delivered as road bulk, rail bulk and bagged cement

Environmental mission

Also addressing the media visit to Dudfield was Hannes Meyer, cementitious executive at AfriSam, who focused on the company’s commitment to environmental issues. He noted that the global cement industry was responsible for about 5% of the world’s greenhouse gases released into the atmosphere. The country was also a significant producer of CO2 emissions.

South Africa is one of the world’s largest and fastest-growing carbon emitters,” said Meyer. “We are in the global top ten of CO2 emitters, when measured per capita.”

As a result, the country had committed to reduce greenhouse gas emissions by 34% below its ‘business as usual’ levels by 2020. As cement manufacturing produces a high level of CO2, he said, AfriSam had been proactive since the 1990s in charting and implementing a path towards environmental sustainability.

Cutting emissions

The innovative step in 2006 to install a baghouse in Dudfield’s Kiln 2 line was part of a broader corporate strategy, built on the values of ‘people, planet and performance’. AfriSam’s value of ‘planet’ is defined as a responsibility for the impact of its actions on the community and the environment.

We were the first company to equip all our kilns with the latest bag filter technology,” he said. “As a company, we are committed to make a difference and to leave a legacy that is positive.”

These initiatives have reduced the company’s particulate emissions to less than a tenth of what they were in 2003. It has also brought emissions to below even the European standard of 30 mg/m3; local regulations require 50 mg/m3 or less.

In the year 2000 AfriSam introduced Project Green Cement to actively reduce its carbon footprint

CO2 programme

Overall, the progress achieved in controlling its plant emissions and making production facilities more energy efficient has had considerable impact on AfriSam’s environmental performance. Between 1990 and the present, its CO2 emissions per ton of cementitious material have been reduced by 35%.

The use of extenders in cement has been an important aspect of these efforts. In 2000, the company launched Project Green Cement – to increase the use of extenders like fly-ash and slag from other industries. This allows the reduced use of clinker – the main consumer of energy in the production process – while making more use of extenders.

We are probably South Africa’s leading company in our understanding and application of extenders in cement,” said Meyer. “This field holds considerable scope for creating more environmentally friendly cements. We are pleased that we have developed the technical expertise to do this.”

In 2009, AfriSam was the first in the industry to introduce a CO2 rating system. This indicates the carbon footprint of each of its cement products, relative to Ordinary Portland Cement (OPC). Indeed, the initiative has gone beyond cement manufacture. Even AfriSam’s other construction materials – aggregate and ready mix concrete – receive a carbon footprint rating. This may also be an industry first, argued Meyer.

Carbon tax

The carbon tax recently introduced in June 2019 will be another pressure for many South African CO2-producing sectors, but also brings opportunities, he said.

There are many good concepts that industry has developed to save energy and CO2 emissions, but the depressed economy has dampened their application,” he said. “Carbon tax revenues could be channelled into incentives that promote energy-saving innovation, with good effect. This would ease demand on Eskom’s grid, contribute toward the country’s Paris Agreement obligations, and make our industries more competitive.”

The company’s environmental efforts include the maintenance of a dedicated Nature Conservation Trust for the full rehabilitation of quarries and mining areas after the closure of operations. It also includes collaboration and support for important players in the conservation space such as the World Wildlife Trust and Cape Nature.

Carbon Tax: Legal Assessment Guide For Companies

Carbon Tax: Legal Assessment Guide For Companies

By Ayanda Msimang

The much anticipated and long overdue Carbon Tax Act came into effect on 1June 2019 – this after president Cyril Ramaphosa signed the Carbon Tax Bill into law in May. During the Minister of Finance’s budget speech in February 2019 it was announced that a carbon tax levy on fuel will be levied at 9c/litre on petrol and 10 c/litre on diesel effective from 5 June 2019, a burden to be carried by both companies and consumers.

1June marked the commencement of the first phase of the Carbon Tax Act, which will continue up until 31 December 2022. The second phase will commence thereafter which will start in 2023 and end in 2030. These phases have been aligned with South Africa’s National Determined Contributions targets to reduce greenhouse gas emissions, determined in accordance with the Paris Agreement. The goal is to reduce greenhouse gas emissions by at least 34% by 2020 and 42% by 2025.

How will carbon tax work?

According to the Act, any person that conducts an activity and emits greenhouse gas emissions (fuel combustion, industrial processes, and fugitive emissions) in the Republic above the prescribed threshold will be liable to carbon tax. However, the thresholds have mostly been set for the energy, manufacturing, construction and transportation sectors, this includes heat and electricity recovery from waste. But will exclude the Waste sector and Agriculture, Forest and other Land Use sectors.  

The initial marginal carbon tax rate on a taxpayer’s greenhouse gas emission has been set at R120 per ton carbon dioxide equivalent. However, due to South Africa’s struggling economy, the carbon tax will range between R6 – R48 per ton carbon dioxide equivalent during the implementation phase which is much lower than the initial rate of R120 per ton carbon dioxide equivalent. The implementation model is basically complemented by tax incentives and revenue recycling measures to allow a smooth business transition with minimal economic impact. The Act creates the following allowances: basic tax-free allowance, fugitive emissions allowance, trade exposure allowance, performance allowance, carbon-budget allowance and offsets allowance. Thus, during the implementation phases the total tax-free allowance could reach a high of up to 95 per cent.

Does carbon tax apply to my company, and if so, how do I go about assessing my position?

In order to have a holistic understanding of the Act’s legal and fiscal implication, it is suggested that companies should perform their assessments in the following manner:

Step one – Applicability

Companies must first determine whether the Act actually applies to their operations. Thereafter, it is imperative for companies to establish the practical implications of the Carbon Tax Act or the effect of the Act on a company’s business operations.

Step Two – Quantum

Companies should determine and establish how much carbon tax will be levied in respect of the companies’ total greenhouse gas emissions. This aspect will require someone with technical knowledge who will calculate the amount of carbon tax to be levied from a company.

Step Three – Financial Ramifications

Once a company has established that the Act applies to its operations and how much carbon tax will be levied from such company, the company should then proceed with seeking a broader understanding of the Act’s fiscal or financial implication.

In essence, the company will then require someone with tax, customs and commercial expertise to conduct a holistic financial assessment of the company’s financial position as far as the impacts of carbon tax are concerned.

It is recommended that companies should seek expert advice on the consequences of the Act to avoid unwarranted confusion when the Act actually kicks in and to attain proper understanding of the relevant regulatory requirements.

Source: Construction World

Environmentally Eco Friendly Readymixes Are Gaining Traction

Environmentally Eco Friendly Readymixes Are Gaining Traction

AfriSam, as part of its efforts to conserve the environment, perfected the art of producing composite cements using additives as partial replacement for cement.

AfriSam uses sustainably sourced materials coupled with environmentally friendly manufacturing processes

While Portland cement served industry for well over a century it has been superseded by composite cements. Using sustainably sourced materials coupled with more environmentally friendly manufacturing processes, these are blends of high performance cement with carbon neutral mineral components designed to achieve excellent cementitious properties.

Depending on the compressive strength, the carbon footprint is reduced by between 46% to 51% when compared to typical industry cement. An example of this is the AfriSam Eco Readymix brands – Starmix, Foundation Mix and Retainer Mix – which were developed to suit particular construction sector applications.

The performance of the Eco Readymix concretes is far superior to concrete made from pure cements. AfriSam can produce ultra-high performance Eco Readymix concretes with compressive strengths of above 70 MPa.”

AfriSam, as part of its efforts to conserve the environment, perfected the art of producing composite cements using additives as partial replacement for cement. Not only does this practice of recycling products from other industries minimise harm to the environment, these additives also enhance the performance of cement and offer advantages over ordinary Portland cement.

The additives include limestone, fly ash (a by-product of coal fired power stations) and ground granulated blast furnace slag from the steel industry. These products behave like pure cements in the presence of cement of lime.

AfriSam perfected the art of producing composite cements using additives as partial replacement for cement

Significantly despite the low carbon footprint, the performance of the Eco Readymix concretes is far superior to concrete made from pure cements. AfriSam can produce ultra-high performance Eco Readymix concretes with compressive strengths of above 70 MPa.

Years of research and development in cement products and in particular C-Tech technology has given several distinct advantages overs pure cements including improved workability, reduce heat of hydration, reduced susceptibility to chemical attack and increased erosion resistance. The resultant concretes are less permeable and more resistant to corrosion. They also continue to gain strength over time.

Nothing wasted, everything gained

Nothing wasted, everything gained

This ultra-modern, sustainable home makes extensive use of recycled materials. To ensure energy-efficiency it incorporates the best of passive design including clever orientation, double glazing, cross-ventilation, strategic shading and the thermal mass of clay brick.

Clay bricks are highly durable and have a life expectancy of hundreds of years. Bricks can also be reused, which minimises waste and distributes their carbon footprint over an extended life span.

Reduce, Reuse, Recycle
Renovation of an existing building can result in significant reductions in both cost and environmental impact compared with levelling the site and rebuilding. Because of aesthetic appeal and longevity, brick masonry buildings often are chosen for reuse. In many cases, load-bearing brick buildings are reused in their entirety. In other cases, the brick walls retained while new facings and extensions are built around the core.
Because of the desirability often associated with genuine brick buildings, adaptive reuse of brick masonry is increasingly popular saving both resources and energy.

Use of salvaged materials avoids the environmental impacts associated with new products. Salvaged brick can be reused, although material performance tests of very old bricks should be done if they are to be used in load-bearing structures. Because of the small, modular nature of brick, scrap brick on construction sites is easily crushed and used for landfill. It is commonly used as sub-base material for pavements, on quarry roads or even as aggregate for concrete.

Due to the strength of clay brick pavers, there is a flourishing market for old pavers, which is used to restore damaged driveways and paths. Because brick is so hardy, packaging on palletised, newly-purchased bricks is minimal and easily recycled.

Reducing waste during manufacture
The brick industry in South Africa is committed to minimising waste and to managing any remaining waste responsibly. As a result, the volume of waste per tonne of production is very low compared with international counterparts, equating to 0.75% when it was last measured in 2014. Numerous initiatives completed by the clay brick industry over the past two years have further reduced these numbers.

Small red- and blue-glazed bricks are combined with recycled clay brick to create an interesting play of light, shadow and colour on this three-story exterior wall. A one-bedroom “studio” has been innovatively extended into a family home – with swimming pool.

Both unfired (also called green) and fired brick are recycled during the manufacturing process. The CBA’s recently completed LCA (Life Cycle Assessment) shows the following efficient use of brick waste during production:

Dematerialisation
Dematerialisation – where bricks are perforated with holes during manufacture – is another way to reduce waste. This decreases raw material and water use during forming as well as reducing energy use during firing. Contractors also prefer perforated products because the bricks are lighter and easier to handle and transport.
However dematerialisation presents challenges in handling the brittle green bricks before and during firing. Several South African brick makers have invested in technology that now allows them to offer perforated products to buyers.

This type of investment in advanced manufacturing techniques supports the clay brick industry’s commitment to the ‘triple bottom line’ – it benefits brick makers, the environment and the communities in which these operations are situated.

Corobrik continues to lead the way in sustainable practices

Corobrik’s robotics allow for flexibility in production, lowering the demand on the energy grid during peak hours

Corobrik continues to lead the way in sustainable practices

While sustainability is becoming commonplace in the construction industry, it has always formed an important component of Corobrik’s business – from the environmentally high-performing clay bricks to every aspect of its business operations.

“Sustainability doesn’t just make sense from a business perspective, it is the social and environmental responsibility of every organisation to incorporate this as part of the company ethos, and this is something Corobrik has never taken lightly,” explained Daniele Torricelli, Director of Engineering at Corobrik. “From the creation of our bricks to the actual nature of the brick itself, sustainability is key. There has been significant investment made in reducing our carbon footprint and Corobrik will continue to adapt as newer technology becomes available.”

The past decade has seen Corobrik investing heavily in more sustainable equipment including advanced extrusion technology at its Phesantekraal factory. The technology reduces energy consumption while also increasing the brick’s fundamental integrity as a weather proof and structural building material, further benefiting the consumer.

Robotics make a significant contribution to reduction of Corobrik’s carbon footprint

New robotics introduced at Corobrik’s Rietvlei and Lawley factories also served to reduce energy consumption on a number of fronts. The robotics allow for flexibility in production, lowering the demand on the energy grid during peak hours. Further to this, the consistent gaps in the setting pattern achieved by the robotics results in easy access of heat during the drying and firing processes, optimising the amount of energy needed for brick production.

Corobrik’s conversion from a coal fired, to a natural gas fired kiln, at its Lawley Factory has resulted in reduced emissions, earning its Lawley factory carbon credits for the effort. As it stands, eight of Corobrik’s factories have attained ISO 14001 Environmental Management Systems.

Committed to sustainability, Corobrik complies fully with the National Environment Management Act of 2014 (NEMA) and all quarries are concurrently rehabilitated in accordance with the individual Mine and Works Programme submitted as part of the application for a Mining Right. Further to this, each Corobrik quarry has its own independently accessed Environmental Impact Access or Environmental Management Plan. These are reviewed by the Department of Mineral Resources at various intervals, as amendments must be made regularly to comply with any changes to the law.

In addition to the stringent sustainability practices adopted by Corobrik, the products also rate highly with respect to their energy efficiency. The thermal property of thermal mass in clay face bricks is widely acknowledged for moderating indoor temperatures, off-setting the need for artificial heating and cooling which results in lower energy use. Human health also benefits because the inert qualities of fired clay means no dangerous levels of volatile organic compounds. The ability of fired clay to absorb and release humidity also results in the optimum humidity level for healthy living.

Torricelli said sustainable practices and innovations are improving on a daily basis: “Corobrik keeps abreast of all industry advancements and every effort will always be made to ensure our practices meet international sustainability-standards. This means a better product for our consumers and an improved global environment.”