Industrial Optimization of Vacuum Disk Filter Dewatering in an Iron Ore Beneficiation Plant

Abstract

Filtration of the final concentrate at the Sanabad iron beneficiation plant is carried out using 16 vacuum ceramic disk filters. The plant survey indicated that the disk filters were operating sub-optimally, with high filter cake moisture (>11%), deteriorating material handling, and reduced pelletizing performance. Industrial-scale trials were conducted to assess the effects of key operating parameters, including feed particle size, disk rotation speed, pulp level, agitator speed, flocculant addition, wash cycle time, and washing acid concentration. Plant-site tests demonstrated that filtration performance improved significantly by increasing feed particle size, reducing disk rotation speed (from 50 to 30 rpm), lowering tank level (from 100% to 50%), increasing agitator speed (from 30 to 50 rpm), shortening the disk washing cycle (from 8 to 6 hours), and increasing washing acid concentration. The addition of a flocculant (anionic polyacrylamide) significantly enhanced both filtration rate and clarity of the filtrate, while the moisture content of the cake remained relatively unchanged. Implementing the optimum conditions identified during plant-site trials resulted in a 1.84% reduction in cake moisture, along with a substantial increase in filtrate clarity. Although the filtration rate decreased due to changes in process conditions, the addition of 10 g/t of flocculant offset this effect, enabling the cake moisture to be maintained at the target value (around 9%). These findings demonstrate that operational adjustments can significantly enhance filtration efficiency and improve downstream process stability, while lower cake moisture may potentially contribute to reduced energy demand in subsequent pelletizing and drying stages.