Alkyl aminated nanocelluloses in selective flotation of aluminium oxide and quartz

There are economic and ecological incentives for developing novel green chemicals from renewable resources in order to reduce the environmental impact of mineral processing. Cellulose, the most abundant natural polymeric source, is a promising green alternative that could replace the synthetic chemicals currently used. In this study, linear alkyl aminated nanocelluloses with increasing chain lengths were used for the selective flotation of aluminium oxide and quartz. Methylamine, ethylamine, n-propylamine, n-butylamine, n-pentylamine and n-hexylamine were introduced into a cellulose backbone using combined periodate oxidation and reductive amination in an aqueous environment. The hydrophobicity of the nanocelluloses was found to be increased by extending the alkyl chain length of the amino groups. Flotation experiments proved that alkyl aminated nanocelluloses can be both effective and selective collectors for quartz in a flotation system if they are sufficiently hydrophobic to allow the particles to effectively attach to the air bubbles. In the case of flotation with a known quartz and alumina mixture, the successful separation solution used aminated nanocelluloses at a pH of around 7.5.