Work at Occidental Research Corporation in the Late 1970’s and Early 1980’s


Partially Melted Feedstock (Low Silica Formulation)

    • The Hard Process is named after Dr. Robert Hard, an Occidental scientist who first discovered that high silica additions to the feedstock composition could be used to inhibit the melting of kiln solids (the melting problem).  Dr. Joseph Megy was the leader of the pyro-metallurgical team.
    • The melting of kiln solids imposed two significant penalties on the kiln phosphoric acid process.  First, the formation of rings and clinker were costly to remove and impeded continuous kiln operation.  Second, the onset of solids melting effectively truncates phosphorus yield, often at low levels.
    • The melting problem had been intractable and represented a fundamental roadblock to the successful development of the kiln phosphoric acid process.

High Silica Formulation


  • High silica formulations result in the formation of long polysilicate chains, which served to inhibit feedstock melting, even at high reduction reaction temperatures.
  • This discovery was a breakthrough for the kiln phosphoric acid process.
  • Occidental Research Corporation patents (now expired):
    • US Patent 4,351,809. Process for Reducing Phosphate Ore. Issued 1982. Joseph Megy and Robert Hard.
    • US Patent 4,351,813. Process for Producing Phosphorus Pentoxide or Phosphorus or Phosphoric Acid. Issued 1982. Joseph Megy and Robert Hard.
    • US Patent 4,389,384. Process for Reducing Phosphate Ore. Issued 1983. Robert Hard.
    • US Patent 4,397,826. Method of Producing Phosphorus Pentoxide in a Kiln with Reduced Carbon Burnout. Issued 1983. Robert Hard and Jacob Mu.
    • US Patent 4,420,466. Process for Producing Phosphorus Pentoxide. Issued 1983. Won Park and Jacob Mu.



Occidental Team Members at Allis Chalmers Pilot Plant, 1982
(Dr. Megy in orange jumpsuit and hard hat)


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IHP Technology Brief

Learn more about JDC’s Improved Hard Process (IHP) and what it means for our resources...