Patents by Inventor Robert J. Grolman

Robert J. Grolman has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 5470559
    Abstract: A process for recycling spent potlining material from aluminum reduction cells contaminated with fluoride and aluminum values. The process comprises first reducing the average particle size of the spent potlining material to smaller than 28 Tyler mesh to form a powder. The powder is then treated with an aqueous sodium hydroxide solution containing about 10 to 60 g/L of sodium hydroxide at a temperature in the range of between 60.degree. and 90.degree. C. to form a solution containing fluoride and sodium aluminate and a residual solid. The solution is removed from the residual solid and the content of NaOH is adjusted in the solution to the range of about 10 to 60 g/L of NaOH, if the content differs from this range, to produce a solution suitable for cyanide destruction. This solution is then heated to a temperature in the range of about 160.degree. to 220.degree. C. at a pressure in the range of about 150 to 350 p.s.i. for a time of between about 1/2 and 3 hours to destroy cyanide values in the solution.
    Type: Grant
    Filed: February 26, 1993
    Date of Patent: November 28, 1995
    Assignee: Alcan International Limited
    Inventors: Robert J. Grolman, George C. Holywell, Frank M. Kimmerle, Gilles R. Turcotte