Brazilian producer outlines their research findings
Brazilian Bauxite producer Terra Goyana and Steinert (TGM) looks to stay competitive by transforming the compact bauxite into a material with accepted calcium and aluminium content and stay up to date with ever growing market standards.
Using Sensor-Based Sorting (SBS) technology can help stay competitive, with reduced costs due to the reduction in processes and resources required for sorting compared to more traditional methods.
This is a step up from previous methods, such as screening which resulted in the retention of anorthosite a more resistant lithology rich in iron and calcium oxide in the coarser fractions.
A benefication flowsheet for the screen materials is required for this process, this requires comminution, magnetic separation, washing, dewatering, or flotation.
Processes such as these inspired the participation with Steinert Latinoamericana, allowing access to sensor-based sorting technology, known as ‘Ore Sorting’. This allows for dry separation by applying sensors that identify the ore’s composition in real-time. This boosts both product quality and reduces the need for water and tailings dams.
José Maurício, TGM's planning manager, said: "The application of Ore Sorter is crucial to meeting the requirements of specific markets, such as the refractory abrasives market, due to the strict standards regarding calcium oxide content."
Partnership began in 2022 between TGM and Steinert, beginning with testing the technology's efficiency. First samples were sent to the Test Centre in Matosinhos, Brazil where Steinert KSS | XT CLI are equipped with x-ray transmission, colour, 3D laser, and magnetic induction sensors to conduct material analysis.
Tests used two tons of samples, ranging from one to four inches. The results showed customisation for the material type was possible with a combination of x-ray transmission and 3D laser.
After the encouraging results, a second round of testing was undertaken. The objective was now to obtain premium bauxite with high aluminium oxide content, and at the same time reducing contaminants such as silicon dioxide, hematite, calcium oxide, and magnesium oxide, in finer size fractions of just one to two inches.
After some fine-tuning, Steinerts technology was capable of rejecting particles with high iron content, significantly increase aluminium oxide levels, and reducing impurities to meet market standards.
Second round of testing showed XRT (x-ray transmission) technology was successful at removing contaminants and achieved the desired parameters and reducing iron oxide contamination in the reject material, with levels between 7% and 22%.
Using Ore Sorter reinforces TGM’s zero-waste concept, making high-value bauxite production possible and commercialisation of reject material for various industries, including cement, ceramics, and metallurgy.
Alexandre Rosa, TGM's PCP supervisor, said: “Bringing together the expertise of those who know the equipment with those who understand the process and the product allows us to identify the ideal operational limits and areas for improvement, facilitating collaborative work to optimize operational profitability and enhance the product.”
Steinret proposed using object formation optimisation technology on its software to improve particle recognition and ejection accuracy. This counteracts the effects of fines in the feed material while meeting the requirements to adjust the processed material’s particles size to half an inch to two inches.
