A method for processing meat-and-bone meal for obtaining ashes includes steps of: feeding a catalytic fluidized bed gasifier with a meat-and-bone meal and an orthosilicate with a gas stream comprising oxygen, for obtaining a synthetic gas stream and ashes, wherein the catalytic fluidized bed gasifier is at a temperature from 400 C. to 1000 C.; grinding the obtained ashes; feeding a thermal boiler with the ground ashes, the obtained synthetic gas and a gas stream comprising oxygen for separating the ashes from the orthosilicate, wherein the thermal boiler is at a temperature from 600 C. to 2000 C.; and collecting the separated ground ashes.