Alternative fuels are increasingly being used in the cement industry to reduce production costs. The cement manufacturing industry is highly capital-intensive, and fuel consumption accounts for almost one-third of the cost of cement production. Due to increased demand for cement in the past few years, most companies have focused on the addition of new capacities. Manufacturers have started to consider alternative fuel sources such as biomass or waste to reduce operating costs, as well as to contribute to a greener environment. In 2018, LafargeHolcim, a Switzerland-based building materials company, reduced net CO2 emissions per tonne of cementitious material by 1% year-on-year to 576 kg CO2/t in 2018 from 582kg CO2/t in 2017, mostly by using alternative fuels.
In November 2014, a study was conducted on the impact of environmental accounting in the cement sector in India. The study revealed the application of environmental accounting helped cement manufacturers reduce and eliminate production and release of damaging pollutants and greenhouse gasses, particularly CO2. According to the study, overall cement emissions could be reduced from 2006 levels by 2050 using less carbon-intensive fuels and by switching to natural gas, biomass and waste derived fuels to heat the kiln. The study also revealed that the use of blended cement made of coal fly ash and blast furnace slag helped reduce CO2 emissions by 20%, while switching from inefficient wet to dry production methods or regular preventive maintenance helped reduce emissions by 40% and bring efficiency in the production process.
The global cement and concrete market is expected to grow from around $483 billion in 2019 to more than $652 billion in 2022 at a compound annual growth rate (CAGR) of 10.4%.
The increased use of alternative raw materials in cement production is delivering improved quality of products and reducing the environmental impact. The main raw material used in cement production has traditionally been limestone. About 60% of the industry’s CO2 emissions are caused by decarbonation of limestone during the production process. The innovations and research and development projects in the industry have already replaced some of the natural raw materials with waste and by-products from other industrial processes. The waste and by-products elements such as calcium, silica, alumina and iron are used as alternative binding materials instead of natural substances such as clay, shale and limestone in cement production. In Europe, for example, about 3-4% of raw materials used in the production of clinker consists of alternative raw materials and ashes from fuel, totaling about 14.5 million tonnes a year. The clinker-to-cement ratio in the EU27 is 73.7%, whereas ordinary Portland cement can contain up to 95% clinker and the remaining 5% is gypsum.