A gasification apparatus and method

Gasifier 10 comprises a primary chamber 20 with feedstock augers 38 and a floor comprising a hearth (24, Fig. 5) which forms a roof of a secondary chamber 35. A mixing chamber 30 has an opening suitable for receiving synthetic gases from the primary chamber and comprises an air inlet fan 26 for adding oxygen for ignition. Heat from combustion of gases is delivered from the mixing chamber to the hearth in the secondary chamber. The secondary chamber includes baffles (29, Fig. 6) under the hearth, and an outlet valve 40. A controller 100 controls flow of gases in the chambers according to sensed pressures and temperatures in the chambers, so that flow through the secondary chamber around the baffles optimises combustion in an after-burner phase, and controls flow rate caused by a downstream fan 80. A heat exchanger 60 may be downstream of the secondary chamber and a feedback circuit (110, Fig. 7) may feed a portion of exhaust gases back into the secondary chamber. A corresponding method is also claimed. The gasifier is particularly suitable for treating organic feedstock.