Robert A. Hard
28Patents
13h-index
25Co-inventors
81Inventor score
Filing activity: Jul 31, 1974 → Nov 11, 2004
Most-cited inventions
| Patent | Title | Area | Cited by | Status |
|---|---|---|---|---|
| US4722756A | Method for deoxidizing tantalum material | Chemistry; Metallurgy | 94 | Expired |
| US6268054A | Dispersible, metal oxide-coated, barium titanate materials | Emerging Cross-Sectional Technologies | 52 | Expired |
| US4960471A | Controlling the oxygen content in tantalum material | Chemistry; Metallurgy | 38 | Expired |
| US7282187B1 | Recovery of metal values | Emerging Cross-Sectional Technologies | 25 | Expired |
| US4602820A | Recovering metal values from geothermal brine | Emerging Cross-Sectional Technologies | 24 | Expired |
| US4360234A | In-situ method and apparatus for sparging gas bubbles | Emerging Cross-Sectional Technologies | 24 | Expired |
| US4390365A | Process for making titanium metal from titanium ore | Emerging Cross-Sectional Technologies | 20 | Expired |
| US4116488A | In-situ mining method and apparatus | Fixed Constructions | 18 | Expired |
| US4470847A | Process for making titanium, zirconium and hafnium-based metal particles for powder metallurgy | Performing Operations; Transporting | 17 | Expired |
| US6843970B1 | Process for recovering metal values by dissolving them in a sulfuric acid solution containing a carbon source and a reducing agent | Emerging Cross-Sectional Technologies | 16 | Expired |
| US5437848A | Recovery of metal values from process residues | Emerging Cross-Sectional Technologies | 14 | Expired |
| US5011742A | Article for controlling the oxygen content in tantalum material | Emerging Cross-Sectional Technologies | 14 | Expired |
| US4351809A | Process for reducing phosphate ore | Chemistry; Metallurgy | 13 | Expired |
| US4045084A | In-situ mining of copper and nickel | Fixed Constructions | 12 | Expired |
| US4359449A | Process for making titanium oxide from titanium ore | Emerging Cross-Sectional Technologies | 11 | Expired |
| US4171146A | Recovery of shale oil and magnesia from oil shale | Fixed Constructions | 10 | Expired |
| US4389384A | Process for reducing phosphate ore | Chemistry; Metallurgy | 10 | Expired |
| US4351813A | Process for producing phosphorus pentoxide or phosphorus or phosphoric acid | Chemistry; Metallurgy | 9 | Expired |
| US4655825A | Metal powder and sponge and processes for the production thereof | Performing Operations; Transporting | 7 | Expired |
| US4595413A | Group IVb transition metal based metal and processes for the production thereof | Chemistry; Metallurgy | 7 | Expired |
| US4397826A | Method of producing phosphorus pentoxide in a kiln with reduced carbon burnout | Chemistry; Metallurgy | 6 | Expired |
| US3951458A | Method of explosive fracturing of a formation at depth | Fixed Constructions | 5 | Expired |
| US4298437A | Method for producing magnesium metal from molten salt | Chemistry; Metallurgy | 5 | Expired |
| US4291920A | In situ exploitation of deep set porphyry ores | Fixed Constructions | 5 | Expired |
| US4241951A | Recovery of magnesia from oil shale | Fixed Constructions | 3 | Expired |
Source: USPTO / EPO open patent data. Inventor disambiguation is heuristic; counts are objective bibliographic measures.