A METHOD AND AN APPARATUS FOR MAKING A MINERAL MELT

The present invention concerns a method and an apparatus for the production of a mineral melt by burning combustible material in the presence of inorganic particulate material and thereby forming a melt, said apparatus comprising : a circulating combustion chamber (1) receiving a supply of a fuel, pre-heated mineral material and a combustion gas and combusting the fuel in the circulating combustion chamber (1) thereby melting the mineral material to form a mineral melt and generating exhaust gases, wherein the exhaust gases are separated from the mineral melt (9) and the exhaust gases are passed upwards through an exhaust pipe (10) to a conduit (11) of a heat exchange system; and quenching means for quenching the exhaust gases at the exhaust pipe (10), wherein the quenching means comprises a quenching hood for quenching the exhaust gases before entering the conduit (11) by drafting a cooling fluid, such as ambient air, Into the flow of exhaust gases around the exhaust outlet (10), and wherein the exhaust pipe (10) extends upwards from the combustion chamber (1) at a height of at least 2.5 times, preferably between 2.5 and 4, more preferably approximately three times, the inner diameter of the exhaust pipe and into the quenching hood so that the exhaust gases exits the exhaust pipe (10) inside the hood.