Implementação de um sistema automático de dosagem de floculante em um espessador de rejeito.

The mineral industry consumes a considerable amount of water in mineral beneficiation processes, which can result in significant environmental impacts if water is used improperly. In order to reduce these environmental impacts and mining costs, companies have been adopting water reuse policies. In this context, low operational efficiency was observed in a tailings thickener at a mining company in the Iron Quadrangle, due to inadequate dosages of flocculant or reagents in general, compromising the efficiency of the process. The consequences of recirculating water with high turbidity include increased water consumption, high operational costs, obstruction of spray jets in magnetic separation, and clogging of water injection nozzles used for ore washing on screens. In view of these problems, this work aims to solve or mitigate them by adapting an automatic flocculant dosing system in the tailings thickener. The project execution methodology was chosen to study ways to automate the flocculant dosing system in the thickener, improving operational efficiency and preventing problems in water recovery and recirculation in the mining circuit. For the implementation of this project, tests of chemical, granulometric, and sedimentation characterization were carried out on the sample, which were essential for the validation and operation of the adaptation of the automatic flocculant dosing system in the thickener. The results of the chemical and granulometric characterization tests indicated a predominance of fine particles, on the order of 0.045 mm in the tailings sample, in addition to a high iron content of approximately 31.23%. Through sedimentation tests, it was determined that the most effective dosage for the dosing equipment is 25 g/ton, resulting in better turbidity, compaction, and sedimentation velocity. Based on the results obtained in the laboratory, the system was implemented in the industrial thickener, obtaining a clarified liquid with a turbidity of 54.6 NTU. It can be concluded that the equipment implementation was successful, presenting satisfactory performances in its operation, such as operational efficiency, assurance of recirculation of clarified water, and a significant reduction in operational costs.