Characterization of a hybrid polyacrylamide and its flocculation properties in cyanide tailing suspensions

Water Sci Technol. 2017 Nov;76(9-10):2482-2493. doi: 10.2166/wst.2017.422.

Abstract

An inorganic-organic hybrid flocculant Al(OH)3-polyacrylamide (Al-PAM) with narrow molecular weight distribution was synthesized using inverse microemulsion polymerization. The hybrid polymer Al-PAM was characterized by Infrared spectroscopy, thermogravimetric analysis, transmission electron microscopy and scanning electron microscopy, and it was found that it had a 'star-like' structure in which Al(OH)3 colloidal particles acted as cores linking PAM chains. The properties of Al-PAM were investigated in flocculating 10 wt% cyanide tailing suspensions. It was found that as the amount of Al-PAMM1 with high molecular weight and aluminum content increased, the initial settling rate of particles accelerated, achieving the maximum 6.6 m/h, 17.3 times the rate of the control without flocculants. The turbidity of the supernatant decreased to 35 ± 2 NTU accordingly, compared to 353 ± 2 NTU of that in the control, which meant that 90.0% of turbidity was removed from the cyanide tailing suspensions. The flocculation mechanism was further explored by floccule size and ζ potential measurements. The superior performance of cationic Al-PAM in flocculating negatively charged particles compared to commercial non-ionic GG indicated that electrostatic repulsion between tailing particles was a crucial factor in deciding the flocculation performance of the polymer. The study demonstrated that both charge neutralization and bridge adsorption were conductive to the particle flocculation.

MeSH terms

  • Acrylic Resins / chemistry*
  • Adsorption
  • Aluminum Hydroxide / chemistry
  • Cyanides / chemistry*
  • Flocculation
  • Molecular Weight
  • Polymerization
  • Polymers / chemistry*
  • Suspensions / chemistry

Substances

  • Acrylic Resins
  • Cyanides
  • Polymers
  • Suspensions
  • Aluminum Hydroxide
  • polyacrylamide