Research & Development

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Research and development of the Resonant Shock Compaction process has been supported by the U.S. Department of Energy (DOE) Entrepreneur's Technical Assistance Program, DOE Argonne National Laboratory with the DOE Mixed Waste Focus Area, Public Service Company of Colorado and the University of Denver. A full scale Resonant Shock Compaction machine is located at the University of Denver, Environmental Materials Laboratory, Denver, Colorado, U.S.A.

 The university of Denver, Environmental Materials Laboratory has facilities to measure properties of RSC products including compressive, flexural and tensile strength, surface and bulk porosity, permeability, acoustic velocity and absorption, and ASTM freeze-thaw durability. Chemical and mineral compositions are measured with scanning electron microscopy, x-ray diffraction and nuclear magnetic resonance. Accelerometer measurements of g-forces and high speed photography are used to measure operating parameters.
 

Research and development is focused upon these three areas: 

• First is recycling coal ash (and other granular industrial waste materials), into construction blocks as strong and durable as concrete blocks but containing 50% to 90% ash. 

• The second is compaction (with up to 50% volume reduction), chemical stabilization and disposal of contaminated soil into strong, durable and low-leaching blocks for disposal. 

• The third is continued study of the RSC particle packing and chemical bonding process.

"Environmental Materials" are broadly defined as those materials or substances whose presence is commonly viewed as waste or as nearly useless by-products of industrial activity. Their disposal or modification represents an environmental challenge: rather than to dispose of such materials in a landfill or dump, they become candidates for conversion to useful & marketable products. Plastic and glass recycling are but two examples. In this laboratory, we are investigating the conversion of coal combustion ashes from power plants into building materials, requiring extensive research and testing as well as characterization. This study involves the application of dynamic compaction to solidify the waste ashes (as well as other granular materials) into useful shapes such as bricks and panels. Currently we are investigating large (800 lb) slabs of compacted ash for durability, strength, and other physical characteristics. As tools we use acoustic pulses and continuous waves for measurement of elastic module, resonant frequencies, and sound attenuation, as well as acoustic emission during deformation. Scanning electron microscopy is another important tool.
Other activities in this laboratory include the remediation of soils contaminated with heavy metals and/or radioactive elements, and water desalination using unique approaches, such as electrostatic ion separation. Polymer electrets are under investigation as a means of affecting ion gradients. Methods of net charge implantation are being studied, as well as the mobility of clustered ions in aqueous solutions in the presence of electric fields.
 

Large Blocks Testing Program by RSC Compaction Technology. Public Service Company of Colorado, other electric utilities, ash management companies, construction companies and a block manufacturers  participated in a test program to fabricate and test large blocks (4 ft. x 3 ft. x 1 ft. and weighing about 1000 lbs.) made from coal ash. A large block mold was fabricated and large blocks made from various ashes. The blocks were tested for strength and durability to demonstrate applicability to construct  walls for commercial and residential buildings. These buildings are expected to be stronger, quieter, more energy efficient and less expensive than wood framed buildings. Some blocks were crushed to make light weight aggregate.  Various surface colorings and textures have been tested. 

Compaction and Stabilization of Low-Level Mixed Waste. This program was conducted in cooperation with the U.S. Department of Energy, Argonne National Laboratory. The RSC technology was compared with a  laboratory hydraulic press, a much more expensive technology limited to producing much smaller blocks than the large RS blocks. Both technologies achieved about 50% volume reduction, 2500 psi compressive strength and low leaching characteristics. 

Criticality/Safety Calculations, 1998. The University of Denver provides expertise in the performance of criticality safety analysis employing up-to-date software. Experience exists in the application of a wide range of powerful and relatively mature transport codes and nuclear data libraries. For example, MCNC 4B has been used for a preliminary investigation of criticality vs. water content as a parameter. 

Particle Packing and Chemical Bonding. RSC ash-based test specimens composed of 65% to 100% ash, have passed ASTM strength and durability test including : compressive strength tests, freeze-thaw cycles, water absorption ratio, aggregate sulfate immersion and . Typical compressive strengths range from 2000 to 5000 psi. Cement, Class C fly ash, clay, phosphates and other binders have been added to mixes of fly ash and bottom ash to achieve these results. No heat treatment is required. High carbon ash, up to 30% carbon, has been compacted successfully as measured by ASTM compressive strength and water absorption tests. High sodium levels (from bag-house sodium carbonate injection) do not appear to interfere with the process.

The RSC process has been commercially applied for ten years to manufacture refectories. About 400 different shapes and sizes of refractories are manufactured. The standard design will process about 100 tons of material per 8 hour shift. The process starts out in a vibration mode and then changes to a stock mode, when the mold containing the ash mix is vigorously impacted upon the shake-table. 

We have studied waste compaction and stabilization for three years and ash-product fabrication for about two years. This is an exciting area of R&D. There are many unanswered questions about RSC particle packing dynamics, the associated inter-particle chemical bonding, and physical properties of the compacted products and their dependence on composition. 

1. Fabricating High Ash Content Building Materials Using Resonant Shock Compaction, D.C. Goss, R.C. Amme, D.J. Frey, R.E. Pressey and K.E. Wier, published in the Thirteenth International Symposium on Management & Use of Coal combustion Products (CCPs), American Coal Ash Association, January 1999. Click Here To Download. 
2. Resonant Shock Compaction of Low-Level Waste: Solidification, Stabilization, and Volume-Reduction, R.C. Amme, K.E. Wier, David J. Frey, R.E. Pressey and R.W. Peters, published in SPECTRUM '98 Supplement, International Conference on Nuclear & Hazardous Waste Management, American Nuclear Society, 1998. Click Here To Download. 
3. Interim Phase Two Report, Further Studies of Resonant Shock Compaction Processing of CCBs, R.C. Amme, D.J. Frey, R.E. Pressey and K.E. Wier, submitted to Public Service of Colorado, 1997. 
4. Comparison of Compaction Techniques in Terms of Structural Integrity and Leach Resistance, R.W. Peters, A.S. Wagh and D.O. Johnson, Energy Systems Division, Argonne National Laboratory, 10^th International Symposium on Gas, Oil and Environmental Bio technology & Site Re mediation Technologies, 1997. 
5. Phosphate Bonding with Harmonic Compaction for Stabilizing Low-Level Mixed Wastes, A.S. Wagh, D.O. Johnson, R.W. Peters et. al., Energy Systems Division, Argonne National Laboratory, Final Report on TTP CH2-6-MW-41 submitted to Mixed Waste Focus Area, U.S. Department of Energy, 1998. 
6. Resonant Shock Compaction: Ash-Based Construction Blocks, R.C. Amme, R.Pressey, K. Wier and D. Frey, Proceedings of International Symposium on Sustainable Construction Using Ashes: Use of Incineration Ash, Section 4, pp 355-367, 2000, ed. R.K. Dhir, published by T. Telford, London, ISBN 7277 2861 X

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