ARMs drive decarbonisation

The use of cementitious materials to reduce the clinker factor and co-processing are two of the pillars of Votorantim Cimentos’ decarbonisation strategy, which also includes energy efficiency, the use of renewable energy sources and the development of new technologies.

In December 2022 Votorantim  Cimentos announced its revised 2030 decarbonisation target of 475kg of CO₂/t of cement. The new global target is 8.7 per cent lower than the target previously announced as part of the company’s commitments, of 520kg of CO₂/t of cement. The new target was approved by the Science Based Target initiative (SBTi) and represents a 24.8 per cent reduction compared to the 2018 baseline. This commitment to science confirms the company’s alignment with the goals established in the Paris Agreement to limit global warming to well below 2°C compared to pre-industrial levels, making every possible effort to limit the increase in global temperature to 1.5°C.

Tackling the negative effects of climate change is at the core of the company’s strategy. Votorantim Cimentos recognises the role, importance and relevance of its decarbonisation journey for the company and the planet. As it reflects on its decarbonisation efforts, the central vision that guides it is the future it wants to build. The company is committed to making continuous and effective progress, as it remains determined to decarbonise its operations and the entire value chain.

In this article, Votorantim Cimentos will address the use of alternative raw materials in cement production, focussing on its initiatives to reduce its clinker factor and increase co-processing. Both are examples of the circular economy, which it boosts by leveraging the renewal and reuse cycle, supporting the value chain and encouraging partnerships between various sectors of the economy, in line with the UN Sustainable Development Goal 17 – Partnership for the Goals. Reflecting the principles of the circular economy, Votorantim Cimentos strives to reduce the use of resources, recycle and reuse materials that would otherwise be discarded, and readjust its choices in pursuit of solutions with a lower environmental impact.

More cementitious materials, less clinker 

The use of cementitious materials, by-products and alternative raw materials from other activities, such as blastfurnace slag, fly ash, calcined clays, limestone filler and other materials to replace clinker, not only supports the circular economy but also drives Votorantim Cimentos’ decarbonisation strategy. Globally, in 2023, the company reduced the clinker factor of its cements to 72.8 per cent (compared to 73.9 per cent in 2022) and its goal is to reach 68 per cent by 2030. In addition to the environmental benefits, the use of cementitious materials in cement production diversifies the product portfolio and expands the possibilities for cement applications. Efforts are being made to find new cementitious materials around the world. In 2023 clays and other inputs were identified at a global level. Throughout the year, these options were tested in a laboratory to assess their potential for use.

In Türkiye, for example, laboratory tests with samples of calcined rocks have found some to be suitable for use in production, while others are pending confirmation. 

In 2023 Uruguay achieved the lowest clinker/cement ratio in the history of the company in the country. This achievement resulted from the implementation of a vertical mill, which primarily optimised the use of limestone filler and clay additions. The company also started a technical feasibility study to incorporate a new addition made of fly ash (a by-product from the local paper industry) into cement.

Co-processing – enabling waste disposal, reducing fossil fuel use

During the cement production process, the temperature in clinker production kilns surpasses 1400°C, requiring a high amount of thermal energy. Co-processing is an approach that enables the reuse of industrial, urban and biomass waste to offset part of the fossil fuels used in the process. This solution contributes not only to reducing the amount of waste sent to landfills but also to reducing CO₂ emissions from clinker production.

Globally, in 2023, 30.9 per cent of Votorantim Cimentos fuels came from alternative sources, representing an increase of 4.4 percentage points compared to 2022. This achievement resulted from several initiatives the company has implemented in all operating regions, including the use of low-carbon alternative fuels, storage infrastructure and crushing sites. In Brazil the company achieved a thermal substitution rate of 34.3 per cent in 2023. The company invested BRL27m (US$4.9m) in the modernisation of the Xambioá site in Tocantins, to increase its level of co-processing and the percentage of AFs in the site’s matrix. In Edealina, in the state of Goiás, it increased the plant’s thermal substitution efficiency by 10 per cent, thanks to an improved ability to measure AFs. At the Rio Branco do Sul plant in Paraná, Votorantim Cimentos invested in a third fan for the limestone mill circuit, to improve the flow of gases and enable higher rates of waste co-processing. At the Salto de Pirapora plant, in São Paulo, a production line modernisation project started that is associated with a US$150m financing agreement the company signed with IFC. One of its goals is to expand the site’s thermal substitution capacity. 

In Europe, Asia and Africa, the highest thermal substitution rate in the history of Votorantim Cimentos was achieved. At the end of 2023, 42.9 per cent of the thermal energy used by its operations came from AFs. At the Alconera cement site, located in the province of Extremadura, Spain, a recently implemented project to replace fossil fuels with alternative materials led the site to reach a thermal substitution rate of 40 per cent in just six months. 

In Uruguay, the AF portfolio now includes waste from pulp mills (biosludge). In 2023, a thermal substitution rate of 29 per cent was achieved by co-processing rice husks, wood chips and biosludge, among other materials.

To support the company in advancing its strategy to increase co-processing, in 2019 it created a waste management and disposal business unit called Verdera, which operates in the environmental solutions chain, repurposing waste. Verdera helps companies and cities minimise the disposal of environmental liabilities that can be reused to produce energy and generate a positive impact by disposing of industrial, urban and biomass waste in an environmentally friendly way.

Verdera offers co-processing services and ensures the safety and traceability of co-processed waste by providing disposal certificates to customers. In 2023 more than 1Mt of waste found new use as fuel and alternative raw materials in Votorantim Cimentos cement kilns in Brazil and North America.

In April 2024 Verdera opened a new waste processing site in Itaperuçu, in Paraná, Brazil. The site receives waste that cannot be recycled and prepares it for disposal using the co-processing technology. The new facility has the capacity to process 48,000tpa of waste.  Occupying an area of 4400m², the processing site is equipped with a state-of-the-art waste crusher that will enable Verdera to prepare new types of non-recyclable materials, such as furniture, palletised products and waste stored in drums, for sustainable disposal.

Waste processed at the Verdera site in Itaperuçu is transformed into clean energy for cement production at the company’s plant in the town of Rio Branco do Sul, in Paraná. Votorantim Cimentos’ investment in the Itaperuçu site, added to local road infrastructure improvements, totalled BRL145m.

Increased competitiveness

For Votorantim Cimentos the climate change agenda can also translate into increased competitiveness. Faced by the growth of regulated carbon markets, the increasing demand for more sustainable products and the issue of climate change, the most competitive companies will be those with the lowest greenhouse gas emission intensity. As a building materials and sustainable solutions company, Votorantim Cimentos is part of the solution for the decarbonisation of the planet. 

This article was first published in the November 2024 issue of International Cement Review.