the crushed material may be further treated after comminution to remove clays and metallic ions that can interfere with the compaction process in a preferred embodiment the crushed material is treated with an acid such as sulfuric acid and deslimed solid fuel that has been comminuted to the desired particle top size is continuously compacted with sufficient force to collapse the porous structure of the fuel thereby mobilizing waters held in fractures voids and pores from the interior of the solid particles to the surface of the solid particles the compaction can be performed at any temperature but is preferably preformed at ambient temperature to avoid adding unnecessary energy or infrastructure costs to the processing the comminuted solid fuel is subjected to a compaction pressure of at least 20 000 kpa preferably the comminuted solid fuel is subjected to a compaction pressure greater than or equal to 100 000 kpa preferably the compaction pressure is no greater than 300 000 kpa more preferably the compaction pressure is no greater than 270 000 kpa any compaction machinery capable of continuous processing at these compaction pressures may be used for the compaction during the solid fuel processing preferably a roller press is used to compact the feed material in one embodiment preferred roller press rolls for use in compaction processes of the present invention have a specific design that delivers higher capacity and lower energy consumption than smooth rolls of conventional roller press roll design preferred roll designs for use in the compaction processes of the invention are described in detail.