绿色基础：推动水泥制造变革的创新

Introduction Sustainability is more than a goal—it's a powerful commitment to shaping a future where both people andthe planet thrive.At its heart, it means meeting our current needs without compromising the ability of futuregenerations to meet theirs. By harmonizing environmental care, social well-being and economic progress,sustainability oƯers a hopeful path forward- one where innovation, responsibility and compassion drive lastingpositive change. In context to creating a better world for us and our future generation, this article focuses on sustainability relatedeƯorts currently being made by the cement industry and those envisaged in the future.Limestone is the mainingredient for producing clinker, that is the key input to produce cement along with other cementitious materials.Limestone is a scarce resource, which over the years will continue to deplete as more and more cement isconsumed. During the same moment of time, the process of limestone calcination is one of the key causes of CO2emission in the entire production process,which is detrimental to the environment. Increasing climate eƯect andscarcity of resources are motivating the industry to seek alternative cementitious materials. Cement is the backbone of modern infrastructure and construction. Being the fundamental component inconcrete, the second largest material consumed on the planet after water. It remains in huge demand, especiallyin developing nations with rapid infrastructure development and urbanization taking place. In 2024 the worldproduction capacity of cement was estimated to be over 7 billion t/yr (tonnes/year) and consumption was about 4billion t (tonnes). Globally, cement demand is envisaged to increase by 3%-5% over the next 5 to 7 years. The importance of cement in rapid infrastructure development and construction, particularly in developingcountries and considering its detrimental environmental impact, compels the industry to give higher emphasis onattaining sustainable practices in its production process. Key Sustainability Challenges Adopting sustainable practices in the hard-to-abate sectors like the cement industry is not easy due to its keychallenges which are given below: 1.High carbon emission from clinker production: Clinker is the main ingredient in cement manufacturing.For producing 1 tonne of clinker, limestone required is around 1.5 tonne, which emits roughly 500 kg (0.5tonne) of CO2. The chemical process of calcination, where limestone (CaCO3) is heated at around 1400OCtemperature to produce clinker, emits CO2which is 55-60% of the total CO2emission from the cementmanufacturing process (assuming Portland Cement CEM-I as per EN 197-1 is produced). Reducingdependency on clinker and/or replacing clinker from the process is a major challenge for the industry. 2.Energy intensive manufacturing process: From limestone extraction to cement transportation to market,the entire process is energy intensive. Energy can be divided into two parts, thermal energy and electricalenergy. a.Thermal energy (fuel) is used to heat the kiln during clinker production. Commonly used fuelincludes coal and pet coke – assuming a judicial mix, CO2emission from fuel is roughly 30-35%of the total CO2emitted during the cement manufacturing process. Use of alternative fuels (AF)such as biomass, plastics, tyres, RDF (Refuse Derived fuel) from municipal solid waste,pharmaceutical/other hazardous waste materials etc., are beginning to gain higher acceptancein the industry. However, the key challenges in AF gaining a much higher traction include reliablesupply chain, technical compatibility with existing kilns and regulatory support. b.Electrical energy refers to power/electricity used in the entire process to produce cement.Around 9%-10% of total CO2being emitted in the cement production process is from powerconsumption. To reduce this emission, industry is moving towards renewable energy (RE) suchas solar, wind, hydro and hybrid (Grid & CPP and renewable sources). The use of RE is dependentongeological and climatic conditions,storage facilities for nighttime and infrastructureavailability. 3.Government support: Government institutes/associations/organizations are starting to support cementcompanies in their pilot projects by providing collaboration opportunities, incentives, subsidies, etc.However, strong policies are still needed to support cement industry’s initiatives such as producing low-carbon cement, adopting alternative fuels and raw materials and advancing R&D in CCUS (CarbonCapture, Utilisation and Storage) technologies. While such policies exist in certain parts of the world, theyneed to be globalized. 4.Technological vs economic viability: Research institutes and cement companies are working towardsdeveloping technologies for reducing CO2emission in the industry. However, the key challenge is inmaking the technology commercially viable and ensuring its widespread adoption across the globe. Current Industry eƯorts Continual