Abstract: A method of firing a lime sludge reburning kiln with a solid fuel at reburning of lime sludge (CaCO.sub.3) to burnt lime sludge is described. The solid fuel is gasified under supply of air to form hot flue gases in a cyclone gasifier, which is built in conjunction with the lime sludge reburning kiln, at a temperature in excess of 1000.degree. C., at which temperature ashes formed melt, after which the molten ashes are separated, preferably into the burnt lime sludge within the lime sludge reburning kiln.

Abstract: A process is provided for heating up wood chips in one or more stages at progressively higher temperatures prior to steaming and pulping in an economical manner at a considerable cost saving; heating the chips in at least a first preheating stage directly with moisture-saturated hot air, optionally admixed with inert gas, having a temperature within the range from about 55.degree. to about 99.degree. C., preferably from 70.degree. to 90.degree. C., having been brought to that temperature in a heat exchanger with hot water or air heaters with waste gases, such as gases drawn at different levels from an evaporator, for example, a Lockman pre-evaporator column.