Patents by Inventor John Y. Stevens

John Y. Stevens 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).

  • Immobilization of thallium during electric arc furnace dust treatment
    Patent number: 6053857
    Abstract: A method and a mixture for chemically stabilizing electric arc furnace dust (EAFD) containing thallium by entrapping the metals inherent in EAFD within a cementitiously hardened product from the mixture. The method includes using the pozzolanic characteristics of EAFD by forming a mixture of EAFD with sufficient water, ferrous sulfate, and Portland cement, then permitting the mixture to react to form a product having a decreased concentration of thallium in its leachate. The method may also include permitting the mixture to form a cementitiously hardened product. The composition of the present invention is the mixture of EAFD, water, ferrous sulfate, and Portland cement. Even immediately after forming the mixture and before hardening, the composition has acceptable leachate characteristics. The hardened product also has acceptable leachate concentrations.
    Type: Grant
    Filed: May 15, 1998
    Date of Patent: April 25, 2000
    Assignee: Conversion Systems, Inc.
    Inventor: John Y. Stevens