Issued Patents 1989
Showing 1–6 of 6 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4830740 | Pyrite depressants useful in the separation of pyrite from coal | Robert D. Hansen | 1989-05-16 |
| 4826588 | Pyrite depressants useful in the separation of pyrite from coal | Robert D. Hansen, Michael J. Fazio | 1989-05-02 |
| 4822483 | Collector compositions for the froth flotation of mineral values | Robert D. Hansen | 1989-04-18 |
| 4820406 | Method for the froth flotation of coal | Robert D. Hansen | 1989-04-11 |
| 4808301 | Flotation depressants | Robert D. Hansen | 1989-02-28 |
| 4797202 | Froth flotation method | Robert D. Hansen | 1989-01-10 |