LC³ – A Viable Solution for Achieving SDGs

Industrialisation has brought comfort to our lives, but at the expense of environmental resources. The quantity of cement produced has increased dramatically because of the growing world population, economic development and rapid urbanisation. The volume of cement production by 2050 is projected to be about 6 billion tonnes. In 2014 alone, 4.2 billion tonnes of cement was produced globally and accounted for 2.7 Gt of CO₂ emissions, approximately 7% of the total anthropogenic CO₂ emissions worldwide, making cement the second largest carbon dioxide (CO₂) contributor in industry after power plants.

Cement is also a resource intensive material. A tonne of conventional cement production requires 1.4 tonnes of limestone. The sheer quantity of cement demand in the future would put measurable and rapid impact on limestone resources around the world.

The most effective strategy for reducing CO₂ emissions and use of natural resources by cement production lies in reducing its clinker content. This can be achieved by substitution of clinker with reactive materials, which up to now have typically been industrial by - products: fly ash from coal fired power stations and blast furnace slag. However, supplies of these materials are limited compared to the amount of cement produced worldwide. We also do not want more coal based thermal power plants in the future. Hence the future availability of industrial wastes is a question mark.
Koilinitic clays have a considerable potential to replace harmful clinker in cement. They are widely available naturally and require very simple processing to be used in cement fabrication. Limestone Calcined Clay Cement (LC³) exploits this potential and reduces the limestone requirement in cement by 50% and CO₂ emissions by 30%. This is the innovation of LC³ - to replace clinker with a widely, naturally available material. The important thing to note is that clay used by LC³ is of a low quality and is left over as a waste by mine owners. Thus, LC³ presents an opportunity to use this mine waste as a resource. Cement companies can easily fabricate LC³ in their own cement plants without changing their existing processes. A small investment to purchase and install a kiln is required to calcine the clay. However, this investment is saved if there is spare kiln available in the existing production line of the cement company.

Practical experience has shown that the production of LC³ even under basic artisanal conditions is possible and produces cement of good quality. This means that the potential of producing LC³ under optimised industrial condition is highly attractive and can certainly be mastered by the major cement companies.

Furthermore, a few demonstration buildings - a house in Jhansi, Central India, some roads and the annex to the Swiss Embassy in Delhi have demonstrated the feasibility of using LC³ on a larger scale.

LC³ is expected to contribute to the following SDGs:

SDG 9: Industry, Innovation and Infrastructure

SDG 11: Sustainable Cities and Communities

SDG 12: Ensure Sustainable Consumption and Production Patterns

SDG 13: Take Urgent Action to Control and Combat Climate Change and its Impacts

LC³ is an innovative product that has the ability to reduce emissions and will contribute in reducing virgin resource use in infrastructure for growing cities. Thus, use of this cement will help in taking urgent action to combat climate change as given in SDG 13.

In the Indian context, LC³ can make important contributions to many of India’s international commitments and national missions. Some of them are as follows:

• India has committed to reduce the Emissions Intensity of its GDP by 33 to 35% by 2030 from the 2005 level. Cement industry in India is a significant contributor to India’s GDP as well as CO₂ emissions. Thus, LC³ proposes important contributions in supporting India towards achieving its INDC. Additionally, the Indian cement industry over the years has transformed itself tremendously towards sustainable production of cement and still remains receptive to new sustainable blends of cement.

• Addressing housing shortage of 2 million units for non-slum urban poor, the Pradhan Mantri Aawas Yojna (Urban) is being implemented during the period 2015-2022 and provides central assistance to Urban Local Bodies (ULBs) and other implementing agencies through States/UTs for affordable housing, slum rehabilitation etc. LC³ can be a viable and low carbon initiative to achieve sustainable growth of housing.

• Smart City Mission, an urban renewal and retrofitting programme aims at renewing 100 cities across India. Thus, there will be immense amount of cement and concrete needed to cater to this programme. Fly ash availability is becoming an issue that will affect production of PPC cement. Hence, LC³ can be an ideal alternative as resource-mapping studies suggest that china clay availability is spread across the country.

Economics and standardisation of LC³ are two key levers that can upscale the production and acceptance of LC³ in India. Quality of LC³ as compared to general purpose cement has already been proven from various lab and field experimentation. However, cement companies will only produce LC³ at large scale when it is standardised by Bureau of Indian Standards and has economic viability for production. The standardisation process in India is slow and complex and economic viability of cement can only be determined by cement companies, as financial information is a matter of discretion. However, it is understood that calcining clay is less costly per tonne than clinker production, because of the lower energy needed (heating the materials to 750-850°C instead of 1450°C) provided it can be carried out on a similar scale and with the same fuel and heat recovery systems as clinker. The cement also uses less limestone, which indirectly increases the mine life of limestone and hence positively impacts the revenue of cement companies. Specific economic advantages are however situation specific and depend on several factors such as the proximity of clay deposits and substitutes (fly-ash, slag) and whether new equipment or land is needed for LC³ production, or if under-utilised equipment can be used?

LC³ has made significant technical progress and has demonstrated enormous potential of savings and the pressing need to reduce greenhouse gases. It is the right time to put this solution into the global climate change dialogue where the world is looking for solutions that can be put to action. Sustainable cement is surely one of the most important one of them. ■

Vaibhav Rathi
vrathi@devalt.org