Case Study CSN plant | Matec Industries

Plant Data

CSN plant and the Minas Gerais Mines

CSN, the Companhia Siderúrgica Nacional, is one of Brazil’s leading steel companies and a fundamental pillar in the country’s mining and metallurgical industry. Founded in 1941, CSN has always played a key role in Brazil’s economic development, thanks to its ability to exploit the nation’s rich mineral resources. The company operates in various regions of Brazil, but its most important and significant mines are located in Minas Gerais, an area known for its abundance of iron ore.

Minas Gerais is the beating heart of Brazil’s mining industry. The region, whose name literally means “General Mines” in Portuguese, has a long history of mining activity dating back to the colonial period. CSN’s mines in this area are among the most productive, significantly contributing to the national production levels of iron and other precious metals. However, with large-scale mining production comes a significant challenge: managing the processing residues, sludge, and their storage.

In mining operations, the management and disposal of sludge are critical issues. These materials, resulting from the extraction and processing of minerals, must be disposed of safely and efficiently to prevent negative impacts on the environment and human health. Traditionally, CSN, like many other mining companies, has used tailings dams to contain these residues. However, increasing production and growing environmental concerns have pushed the company to seek more sustainable and innovative solution.

Answering the needs: CSN – Companhia Siderúrgica Nacional

To address this complex challenge, CSN decided to partner with Matec Industries, a leading global sludge and wastewater treatment company, which handled the entire project from the engineering level down to the civil works, essentially becoming a trailblazer in the country in this type of process called Dry Stacking. The partnership, initiated in 2018, led to an ambitious project aimed at completely eliminating the need for these dams at CSN’s iron mine “Casa De Pedra” in Minas Gerais, the biggest dam in a city area of all the Latin America. The solution proposed by Matec is structured in three main phases, each aimed at increasing sludge treatment capacity and improving the plant’s operational efficiency.

Phase 1: the beginning of the transformation

The first phase of the project began in April 2018 with the installation of four Magnum 2000×2000 filter presses, each equipped with 190 plates. These filter presses were designed to handle large volumes of sludge, ensuring effective separation of mineral solids and clay from the residual water. Additionally, two vertical silos with a capacity of 550,000 liters each were installed for the decantation and clarification process and the recovery of clean water.

The implementation of this equipment achieved an hourly production of almost 550 tons of dry material. This treatment capacity represented a significant first step towards eliminating tailings ponds, immediately reducing the amount of accumulated sludge and improving water resource management. Phase 1 demonstrated the effectiveness of Matec’s technology and laid the foundation for subsequent phases of the project.

Phase 2: expansion and capacity increase

The second phase of the project, which began in March 2019, saw a further expansion of treatment capacity. In this phase, five more Magnum 2000×2000 filter presses, also equipped with 190 plates each, were installed. Additionally, four new vertical silos were added for a total capacity of 3.9 million liters.

This expansion increased the hourly production of dried sludge to almost 650 tons, significantly enhancing the plant’s efficiency and further reducing the reliance on tailings dams. The increased treatment capacity allowed CSN to manage sludge more effectively, reducing operational costs and improving the sustainability of mining operations.

Phase 3: completion and optimization

The final phase of the project, which began at the end of 2021, saw the installation of two additional Magnum 2000×2000 filter presses and the addition of a fixed bridge High Rate horizontal thickener with a diameter of 40 meters. This phase brought the plant’s overall capacity to over 30,000 tons of dry sludge treated per day.

With the implementation of Phase 3, CSN’s sludge treatment plant became one of the most advanced and capable in the world. Operating 24 hours a day, 365 days a year, the plant is able to treat enormous volumes of sludge, completely eliminating the need for tailings ponds. This transformation brought numerous benefits, including the reduction of dam collapse risks, significant water savings, elimination of potential contamination risks, and reduction of disposal costs.

A sustainable future for CSN plant

Thanks to the collaboration with Matec Industries and the implementation of the new sludge treatment plant, CSN has taken a decisive step towards the sustainability and safety of its mining operations. The elimination of these dams has drastically reduced the risks associated with possible dam collapses, protecting the surrounding environment and local communities. Additionally, the plant’s efficiency has allowed the client to save precious water resources and reduce operational costs.

This project represents an exemplary model for the global mining industry, demonstrating how technological innovation can solve complex problems and improve the sustainability of industrial operations. CSN, with the support of Matec, has shown that it is possible to reconcile productivity and respect for the environment, creating a safer and more sustainable future for all.