APLICAÇÃO DE FLOCULANTES EM PÓ PARA SEDIMENTAÇÃO DO RESÍDUO BAYER NA INDÚSTRIA DO ALUMÍNIO.

The alumina production through Bayer process generates a large amount of residue known as red mud. Once separated from green liquor (GLQ), red mud is direct to washing steps where synthetic flocculant dosage promotes solid liquid separation. The goal is thickening the slurry to recover caustic sodium as much as possible. The use of powder polyacrylamide with high molecular weight and suitable ionic charge results in significant gains in terms of dosage, settling rate, underflow compaction and overflow turbidity. However, the alumina industry in Brazil still using emulsion flocculants despite the reported benefits. In this paper was evaluated the performance of different powder flocculants from BASF (Alclar® line). In addition, was performed a comparison between powder polyacrylamide and emulsion flocculants associated or not with hydroxamates. [ABSTRACT FROM AUTHOR]