NOVELTY - Preparing particulate carbon fuel comprises finely dividing carbon particles, introducing the finely dividing carbon particles into the fuel cell, introducing a gas containing oxygen into the fuel cell, and exposing the finely divided carbon particles to carbonate salts, to molten sodium hydroxide, potassium hydroxide and/or lithium hydroxide, to mixed hydroxides, or to alkali and alkaline earth nitrates.    USE - The method is useful for the preparation of particulate carbon fuel, which is useful in a fuel cell (claimed) used: for direct carbon conversion; in efficient electric power generation; in broad mobile, transportable and stationary applications; and in electric power generation at high efficiencies from coal, petroleum derived fuels, petroleum coke and natural gas.    ADVANTAGE - The method: conserves precious fossil resources by allowing more power to be harnessed from the same amount of fuel, which improves the environment by decreasing the amount of pollutants and carbon dioxide emitted into the atmosphere per kilowatt-hour of electrical energy that is generated, and decreases emissions of carbon dioxide, which are largely responsible for global warming.    DETAILED DESCRIPTION - Preparing particulate carbon fuel, comprises finely dividing carbon particles, introducing the finely dividing carbon particles into the fuel cell, introducing a gas containing oxygen into the fuel cell, and exposing the finely divided carbon particles to carbonate salts, to molten sodium hydroxide, potassium hydroxide and/or lithium hydroxide, to mixed hydroxides, or to alkali and alkaline earth nitrates, where the step of exposing the finely divided carbon particles comprises: exposing the finely divided carbon particles to carbonate salts of lithium, potassium, sodium, magnesium, calcium and/or barium, to a hot carbon dioxide gas stream above 700 degrees C, to vapors in equilibrium with molten sodium hydroxide, potassium hydroxide or lithium hydroxide, or mixtures of alkaline earth and alkali carbonates and hydroxides, or to a mist of a low-melting eutectic of mixed hydroxides; reacting the finely divided carbon particles and the low-melting eutectic of mixed hydroxides with carbon dioxide; mixing the finely divided carbon particles with mixed alkali metal and alkaline earth nitrites and hydroxides; or milling the finely divided carbon particles with mixed alkali metal and alkaline earth nitrites.    DESCRIPTION OF DRAWING(S) - The figure shows the fuel cell system constructed.    Fuel cell body (201)    Molten mixture of alkali or alkaline earth metal carbonates electrolyte (202)    Carbonaceous fuel (204)    Anode (205)    Cathode (206)