A method for heating materials by application of radio frequency (“RF”) energy is disclosed. For example, the disclosure concerns a method for RF heating of petroleum ore, such as bitumen, oil sands, oil shale, tar sands, or heavy oil. Petroleum ore is mixed with a substance comprising susceptor particles that absorb RF energy. A source is provided which applies RF energy to the mixture of a power and frequency sufficient to heat the susceptor particles. The RF energy is applied for a sufficient time to allow the susceptor particles to heat the mixture to an average temperature greater than about 212° F. (100° C.). Optionally, the susceptor particles can be removed from the mixture after the desired average temperature has been achieved. The susceptor particles may provide for anhydrous processing, and temperatures sufficient for cracking, distillation, or pyrolysis.