The Role of High Molecular Weight Polyethylene Oxide in Reducing Quartz Gangue Entrainment in Chalcopyrite Flotation by Xanthate Collectors

• Author / Creator

  Gong, Jihua

• Fine particles pose two challenging problems to all mineral processors around the world today. The problems are the inefficient collection of hydrophobic particles (low recovery), and mechanical/hydraulic entrainment of hydrophilic gangue particles (low concentrate grade). Extensive research has been conducted to improve the flotation recovery of fine hydrophobic particles. However, much less effort was made to lower the mechanical/hydraulic entrainment of fine gangue mineral particles.

  In this study, polyethylene oxide (PEO) was used to flocculate and depress fine quartz particles. Batch flotation results indicated that the addition of low dosages of PEO improved value mineral recovery and concentrate grade in the flotation of artificial mixtures of chalcopyrite/quartz and a commercial Au-Cu sulfide ore sample. It was found that PEO adsorbed on both minerals mainly through hydrogen bonding and caused non-selective flocculation of quartz and chalcopyrite, forming large hetero-aggregates. However, the addition of potassium amyl xanthate (KAX), a specific sulfide mineral collector, adsorbed on chalcopyrite through chemical interaction, replaced PEO and caused the chalcopyrite particles to break away from the hetero-aggregates, forming separate homo-aggregates of quartz and chalcopyrite. The flotation of the chalcopyrite and the depression of the quartz were thus both improved due to the larger sizes of the homo-aggregates compared to the discrete particles.
  
  It was also observed that a completely solubilized PEO solution could not flocculate quartz, while a partially solubilized PEO solution was most effective. This was attributed to the better “bridging” functions of the undissolved PEO aggregates when it was partially solubilized. When the PEO was fully solubilized, the individual PEO molecules were probably too flexible and tended to flatten on the adsorbed solid surface and thus could not function as an effective bridging flocculant.

  Furthermore, it was found that PEO could function as a “collector” for quartz due to its affinity to air-water interface and quartz, and it could increase quartz entrainment when used at high dosages. Selective flocculation and depression of the quartz gangue during chalcopyrite flotation could only be achieved at low PEO dosages. The implication of these observations on how to utilize the polyethylene oxide in industrial flotation was discussed.

• Subjects / Keywords

  • Chalcopyrite flotation
  • Sulfides
  • Polyethylene oxide
  • Gangue entrainment
  • Flocculation

• Graduation date

  Fall 2011

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R3NK91

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.