291907 Treatment of Bauxite Tailings Into Useful Products

Monday, October 29, 2012
Hall B (Convention Center )
Paige Kleinow, Chemical Engineering, Michigan Tech University, Houghton, MI and Gerard Caneba, Michigan Tech University, Houghton, MI

Aluminum is a packaging material that is almost 100% recyclable, and it is a relatively inexpensive metal that has a high strength-to-weight ratio.  In its production from bauxite ore, the Aluminum is extracted using a highly basic caustic solution, and the spent ore (tailings) is a red caustic particulate material that poses risks to human health, to the groundwater, livestock, and to the natural and built environment.  This poster involves the preliminary investigation of properties of polymer composites containing red mud bauxite tailing particulates that are treated with in-house generated vinyl acetate (VA)-based block copolymers.  The technical approach involves the use of reactive biodegradable vinyl acetate-acrylic acid-based copolymer materials that function simultaneously as cleaning surfactant, fast caustic neutralizer, binder, and coupling agent for facilitating reuse of treated dried red mud powder.  The proposed transformative solution involves the use of multifunctional copolymer surfactants that have biodegradability characteristics, able to neutralize and become a surface coupling agent for use of the dried red sludge in a composite formulation.  The surfactant class is a neutralized version of a tapered block copolymer of vinyl acetate and acrylic acid (VA-AA), which was co-developed between G. Caneba’s group at Michigan Technological University and the Corporate Research group at National Starch and Chemical Co. in 1999-2000.

The research project involves the following tasks:

  1. Assist G. Caneba and his group in the preparation of the VA-based surfactant emulsions, to be used to surface treat red mud particulate materials obtained from Rio Tinto;
  2. Carry out Microtox biodegradability testing of the surfactant emulsions;
  3. Prepare red mud samples from Rio Tinto for experimentation;
  4. Treat red mud samples with the polymer surfactants;
  5. Prepare treated red mud samples for consolidation into test samples;
  6. Preparation of test samples from treated red mud samples;
  7. Applications testing of benchscale product samples.

So far, we found the treated red mud material to require only 3-7 wt % VA-based surfactant solid in total solids down to pH=8, and with very low levels of aquatic toxicities.  We are also able to incorporate the treated red mud material into various products, including paints, cements, and polymer composites.

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