Issued Patents All Time
Showing 1–5 of 5 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 5458744 | Process to produce hydrogen and/or hemihydrate calcium sulphate from calcium sulphite | Donald W. Kirk, Richard L. Hummel | 1995-10-17 |
| 5204084 | Hydrometallurgical production of zinc oxide from roasted zinc concentrates | Donald H. Eberts | 1993-04-20 |
| 5028410 | Hydrometallurgical production of zinc oxide from roasted zinc concentrates | Donald R. Spink, Kim Nguyen | 1991-07-02 |
| 5017346 | Process for treating zinc oxide bearing materials | Donald R. Spink, Kim Nguyen | 1991-05-21 |
| 4789529 | Recovery of zinc from zinc bearing sulphidic ores and concentrates by controlled oxidation roasting | Donald W. Kirk, Bruce Jue | 1988-12-06 |