The need of modern science to achieve a sustainable future development through strategies less harmful to environment has been a major research focus. Nature has continuously provided materials for many applications. Thus, polysaccharides, in natural or chemically modified form, have become increasingly attractive to both research and industrial communities, due to their good solubility in water, high chemical reactivity and viscosity, at low cost and toxicity. An example of such biomaterials is xylan, extracted from corn fiber, used in the industrial production of iron ore pellets and other high-quality metallurgical raw materials, which requires the use of flotation to reduce impurities content.The special affinity of the iron oxide minerals for polysaccharides led to the use of xylan to facilitate their depression during reverse cationic flotation of silica. Comprehensive characterization of the materials involved in this process is a crucial requirement, especially challenging in the case of natural products, where variations due to different sources and extraction conditions may affect performance. Light scattering-based unique methodologies together with traditional methods (FTIR, SEM, TGA) were used in the characterization studies of xylan samples extracted under different conditions, with focus on quantification of sample components (protein, lignin, amylose/amylopectin) and on understanding of how critical parameters, such composition, molecular weight distribution, size, hydrophilic/hydrophobic character, and structure affect their performance as depressants. Monitoring viscosity and light scattering signatures during these modification reactions allowed correlations between polymer characteristics and variables used in extraction process (NaOH, H2O2) to be made by following their evolution in real time and led to process optimization. It is hoped that the knowledge gained from these studies will offer convinicing arguments in proving that the modified polysacharides represent efficient depresants.

Macromolecular characterization of biopolymers as alternative depressants for iron ore flotation

253rd National Meeting (2017)

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