Terra Goyana and STEINERT: How ore sorting technology is transforming bauxite beneficiation
Terra Goyana Mining (TGM) benchmark themselves in mineral research, development, beneficiation and bauxite commercialization. Representing 5.5 % of national production, the company stands out among Brazil’s largest producers. With operations at the Barro Alto mine (Goiás) and an office in Goiânia, TGM maintains a strong presence in the international market, establishing commercial relationships with partners in South America, Europe and Asia. TGM is part of the Supergram group, which operates in various sectors, including commercial bauxite extraction. Through Bautek, a producer of calcined bauxite, the group strengthens the vertical integration of its product. The company is also present in Poços de Caldas, Minas Gerais/Brazil.
To ensure a competitive product, TGM faces environmental, social and especially commercial challenges. The goal is clear: Transform compact bauxite into a material with accepted calcium and aluminium content, to meet increasingly stringent market standards. With advancement in mining operations, the need for innovative technological solutions has become even more urgent.
In this scenario, the implementation of Sensor-Based Sorting (SBS) technology emerges as a solution to meet the market requirements. Previously, material classification was done through screening only, which resulted in the retention of anorthosite a more resilient lithology rich in iron (Fe) and calcium oxide (CaO) in the coarser fractions.
As the next step in the project’s development, the creation of a new, higher-value-added product was planned. The primary requirement defined was to ensure efficient impurity removal to reduce calcium contamination below 0.15 %. Additionally, increasing the aluminium oxide (Al2O3) content range between 62 and 63 % would be beneficial, as it would enable the production of a premium material.
To accomplish this objective, developing a beneficiation flowsheet for the screened material would be required. Conventional bauxite processing flowsheets involve stages such as comminution, magnetic separation, washing, dewatering or flotation. It was in this context that the partnership with STEINERT Latinoamericana, a company of STEINERT GmbH, Cologne/Germany, was established, providing sensor-based sorting technology, also known as “Ore Sorting”, to the forefront of operations. Unlike conventional methods, Ore Sorting enables dry separation applying sensors that identify the ore’s composition in real time. This solution not only enhances product quality but also eliminates the need for water and tailings dams, promoting a more sustainable and efficient operation.
With this innovation, TGM not only enhances its competitiveness in the industry but also positions itself as a benchmark in sustainable mining, aligning with best environmental practices and the growing global demand for more responsible operations.
The collaboration between TGM and STEINERT began in 2022 with testing to validate the technology’s efficiency. Samples were sent to the Testing Centre in Matosinhos, Minas Gerais/Brazil, where the STEINERT KSS | XT CLI equipment which are equipped with X-ray transmission, colour, 3D laser and magnetic induction sensors to enabled precise material analysis (Figure 4).
In the first round of tests, using 2 t of samples from 1″ to 4″, the results were exceptional: a customized configuration for each material type, with a standout combination of X-ray transmission (XRT) and 3D laser, ensuring highly efficient separation.
This initial success led to a second round of testing, focused on an even greater challenge: obtaining premium bauxite with high Al₂O₃ content while reducing contaminants such as SiO₂, Fe₂O₃, CaO and MgO, in a finer size fraction of 1″ to 2″.
After fine-tuning the process, STEINERT’s technology demonstrated its full capability to:
- reject particles with high iron content;
- significantly increase Al₂O₃ levels;
- reduce impurities to meet market standards.
The second test confirmed the efficiency of XRT technology in removing contaminants, achieving the desired parameters (CaO < 0.1 %) and reducing Fe₂O₃ contamination in the reject material, which showed levels between 7 and 22 %.
TGM’s strategy for directing Ore Sorter products reinforces the zero-waste concept, enabling the production of high-value bauxite and the commercialization of reject material for various industries, such as cement, ceramics and metallurgy. This expands both sustainability and the economic feasibility of the process.
One of the improvements proposed by the STEINERT Latinoamericana team during the initial phase of the pilot plant was the use of object formation optimization technology on its software to improve particle recognition and ejection accuracy. This optimization helped counteract the effects of fines in the feed material while meeting the requirement to adjust the processed material’s particle size to 1/2″ to 2″. As a result, data accuracy increased, result variability decreased, and plant productivity improved significantly.
With the proven effectiveness of Ore Sorting, TGM acquired its first STEINERT sorting system, replicating the excellent laboratory results on an industrial scale. TGM’s ore, derived from the leaching of anorthosite, contains high calcium levels, making separation a critical challenge. The use of XRT, which correlate the atomic density of the particles, proved to be the ideal solution for this scenario, enabling precise separation of bauxite from anorthosite and ensuring operational efficiency directly at the mine.
After more than a year of operation, the partnership between TGM and STEINERT has been strengthened. STEINERT provides continuous support, with remote assistance and regular technical visits to optimize processes and make personalized adjustments in line with new market demands.
“We rely on the excellent support from the technicians at STEINERT Latinoamericana who are in constant contact with me and the operators, always ready to correct failures – something common in any process, regardless of the time,” says Osmar Ribeiro, Beneficiation Supervisor at TGM.
During the assisted operation of the pilot plant, it was observed that the variation between the two predominant seasons in the region rainy and dry directly impacts the efficiency of separation due to changes in the material’s characteristics. In response to this challenge, the STEINERT global team actively worked to mitigate the production impacts and remains constantly attentive to provide support for the improvement of mineral operations. As a result, the companies have established a solid partnership based on technical collaboration and continuous project development (Figure 2).
TGM’s process is 100 % dry, using water only for infrastructure activities. This differentiator is fully aligned with the company’s ESG practices, reinforcing its commitment to more sustainable mining. With the implementation of the STEINERT Ore Sorter technology, TGM significantly increased the selectivity of the process, resulting in cleaner, higher-quality products that can be directed to new markets with more stringent requirements, without the need for wet beneficiation. Additionally, there was an increase in available reserves, as improving classification efficiency and ore recovery allows for better use of the deposit, thereby reducing future environmental impacts.
This technological evolution not only enhanced operational efficiency but also brought the company closer to one of its main goals: achieving zero waste production, consolidating a sustainable and profitable business model. This advancement is in complete harmony with STEINERT’s philosophy, which generally promotes sustainability through innovative technological solutions. These technologies not only optimize processes and reduce waste but also reinforce the commitment to the circular economy, efficient resource use and sustainable development, aligning with environmental preservation principles and the enhancement of industrial processes.
Today, the STEINERT Ore Sorter is a strategic pillar for TGM, providing not only efficiency and quality gains but also aligning with the internal project “Mine of the Future”, which represents the level of excellence the company seeks to achieve. This project incorporates features such as environmental responsibility, innovation and maximization of mineral utilization.
The success at Barro Alto is a clear example of how technology, when properly applied, can transform challenges into solid and lasting results.
Further information/Weitere Informationen:
STEINERT GmbH
www.steinertglobal.com
