Heat treatment of material

DETAILED DESCRIPTION We claim: 1.
Apparatus for the heat treatment of a material in discrete form including a horizontally elongate combustor adapted to contain a fluidised combustion bed of particulate material and having at least one horizontally elongate imperforate thermally conductive wall for indirect heat exchange therethrough, a fuel inlet for the combustor, an exhaust gas outlet for the combustor, a heat treatment vessel disposed alongside the combustor and enclosing at least the said wall to receive heat transmitted therethrough from the combustion, the vessel being adapted to contain a bed of material in discrete form, a material inlet and a material outlet in the vessel, a plurality of heat exchange means passing through the vessel and communicating with the exhaust gas outlet of the combustor, and downwardly directed perforated gas distribution means located in the vessel and connected to the heat exchange means, the gas distribution means extending into the base region and releasing at diverse points across the plan of the vessel at a plurality of horizontally spaced locations.
2.
A method for the heat treatment of a material in discrete form, the method including the steps of burning a fuel in a fluidised combustion bed contained within a combustor having at least one thermally conductive imperforate wall, arranging a heat treatment bed of the material so as to receive heat through said wall, forming combustion gases from the combustion bed directly into a plurality of spaced streams in which each stream in turn is formed into a plurality of smaller streams released at diverse points across the plan of the heat treatment bed, introducing said smaller streams into the base region of the heat treatment bed downwardly thereby distributing the gases throughout the base region of the heat treatment bed which is fluidised at least partly by said gases, and passing the combustion gases from the combustion bed in heat exchange relation with the heat treatment bed prior to the introduction of the gases into the heat treatment bed