Samarco has been using advanced process control with proven benefits, recognizing that the use of these technologies is a constant necessity. In the main stages of the production process, the "Advanced Process Control System" (SCAP) is employed, which consists of a multivariable control based on conventional control tools and fuzzy logic, simulating human thinking in decision-making.

SCAPs are computer programs that incorporate specific tools and knowledge to solve operational tasks, controlling the processes autonomously and intelligently. The practices and expertise of specialists are incorporated into the systems through the control strategy, usually aiming to stabilize and optimize the production processes. The strategy is composed of models and rules, constituting the intelligence of the system for decision-making.

The expert system maximizes the profitability of the operation of the most important equipment involved, from the iron ore beneficiation to the fired pellet. These systems automatically receive information from the controllers and use various advanced techniques to generate new appropriate set-points for the process at a very high frequency. These set-points are established to continuously pursue the objectives of Samarco's control strategy in different stages of the production process.

In the flotation stage, where the ore is separated from contaminants such as silica, the control method that best reflects the strategy and produces the best results is fuzzy logic, which consists of a set of rules that reproduce the best operational practices. Accompanying the expert system is the foam image analysis system, which measures the drag velocity, crucial for control. Another established and patented technology used by Samarco is the online silica analyzer, which provides information about the silica trend in the concentrate, as well as X-ray analyzers, which provide the iron trend in the tailings. These tools have contributed to maximizing the metallurgical recovery in conventional flotation and reducing the variability of silica content in the final concentrate. The main objective was to maximize the metallurgical recovery in conventional flotation and reduce the variability of silica content in the final concentrate. Combined with the foam image analysis system and the online silica analyzer, the tool has proven capable of achieving the expected objectives, bringing stability to the process, standardizing operations, and reducing input consumption by approximately 17.78%.

In the filtration stage, vacuum pressure and the number of pumps are adjusted to achieve the appropriate moisture level for the pelletizing stage. SCAPs play a decisive role in adjusting vacuum pressure and automating filter rotation cycles to optimize moisture and process productivity. In addition to reducing variability, there has been a reduction in moisture of approximately 2.26%. 

In the iron ore green pellet formation, it is a dynamic process with complex control requirements. In manual control, the local operator is responsible for process adjustments, and the timing and proportion of their actions depend on individual perception. With the implementation of the pelletizing SCAP, were achieved automated, standardized, and optimized control of the green pellet growth rate on the pelletizing discs. After implementation, there was a reduction in pellets out of size specification, a reduction in input raw material’s consumption, improvement in the quality of the final product and high productivity. The variability was reduced by 37.4%, the size range of 8 to 16 mm was increased by approximately 1.15% and productivity increased by approximately 6.1%.

For controlling the variables in the pelletizing plant’s furnace, the SCAP's actions determine the optimal configuration of the fans based on the temperatures and pressures of the wind boxes. The controller also optimizes the ideal burning profile based on the grate feeding rate. The result is a reduction in variability with an improvement in the physical quality of the burnt pellets. Variability was reduced by 49.8%, specific gas consumption decreased by approximately 19.58%, and thermal consumption decreased by approximately 10.54%.

Optimized decision-making improves process control by reducing variability and shifting averages towards operational limits. The observed benefits include capacity/production optimization, yield optimization, loss reduction, cost reduction, improvement in the quality of the final product, environmental compliance, and others.

This article aims to describe how SCAP processes input information through conventional calculations and statistical calculations combined with "crisp" and "fuzzy" rules in order to reduce variability in the main stages of the production process.