Prototype of an Automation System for Hazardous Chemical Dosing in the Graphite Leaching Process

Abstract

In the industrial context, handling corrosive and toxic chemicals poses a high risk due to their adverse health effects and potential to cause life-threatening situations. Automating this process emerges as an effective solution to minimize these risks. The present work aims to develop a prototype of an automation system for the dosing process of chemical products and the preparation of an acidic solution for use in graphite leaching in companies that process this mineral. The goal is to prevent direct human contact with these substances, thereby reducing the risk of accidents. To achieve this objective, industrial automation techniques were applied. The development included the creation of a functional description specifying the expected system behavior and operator interaction via HMI (human-machine interface), as well as the identification of all field devices. The instrumentation utilized level transmitters and load cells to send data to the PLC (programmable logic controller), which converts these signals into useful values. The field valves were controlled by the PLC’s digital outputs, with position feedback. The PLC programming was carried out using TIA Portal V17 software, employing ladder logic and function block diagrams, optimizing the logic for code reuse. The HMI screens, using the Siemens TP700 Comfort 7" model, displayed the status of tanks and valves, operating modes, and alarms, and communicated with the PLC via PROFINET. It is expected that this work will contribute to the dissemination and application of industrial automation technologies, promoting greater safety and risk reduction in industrial processes involving hazardous chemicals.