Patents by Inventor Hiroyuki Tamura

Hiroyuki Tamura 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).

  • Method for manufacture of arsenious anhydride
    Patent number: 4438079
    Abstract: Arsenic anhydride of high purity is inexpensively manufactured from an arsenic sulfide-containing substance by first contacting the arsenic sulfide-containing substance with a copper sulfate-containing aqueous solution so as to provide an extract solution containing arsenious acid, the extract solution is subjected to aeration in the presence of copper ions such that the arsenious acid therein is mostly oxidized to arsenic acid, the thus provided treated solution is subjected to a weak reducing agent to cause crystals of arsenious anhydride to form, and these crystals are then recovered.
    Type: Grant
    Filed: March 26, 1982
    Date of Patent: March 20, 1984
    Assignee: Sumitomo Metal Mining Company Limited
    Inventors: Tadashi Nakano, Hiroyuki Tamura, Naoki Kubo