NOVELTY - Operating shaft furnace (2) produced from carbonate-containing raw materials, preferably quicklime, dolomite, magnesia or cement, comprises supplying a carbon-containing fuel and/or substitute fuel, supplying industrially produced oxygen, and combusting a mixture of the carbon-containing fuel and/or substitute fuel and oxygen; calcining carbonate-containing raw material; additionally introducing carbon dioxide; removing exhaust gas comprising carbon dioxide, and introducing the exhaust gas into an exhaust gas reservoir (4); and producing methane and methanol from carbon dioxide and hydrogen.    USE - The method is useful for producing quicklime or cement (claimed).    ADVANTAGE - The method makes use of released carbon dioxide for preparing methane and methanol, and thus it completely avoids carbon dioxide emission in the process.    DETAILED DESCRIPTION - Operating shaft furnace (2) produced from carbonate-containing raw materials, preferably quicklime, dolomite, magnesia or cement, comprising at least one upper raw material inlet zone, at least one central combustion zone, and at least one lower combustion material outlet zone, comprises (a) supplying a carbon-containing fuel and/or substitute fuel to the combustion zone of the shaft furnace, supplying industrially produced oxygen to the combustion zone and/or the outlet zone of the shaft furnace, and combusting a mixture of the carbon-containing fuel and/or substitute fuel and oxygen in the combustion zone of the shaft furnace, (b) calcining the carbonate-containing raw material in the combustion zone and above it, (c) additionally introducing carbon dioxide into the combustion zone and/or the outlet zone of the shaft furnace respectively as a substitute of nitrogen-containing atmospheric air, (d) removing exhaust gas comprising at least 60 vol.% carbon dioxide, obtained from the combustion of the fuel with oxygen and the supplied carbon dioxide, at an inlet opening of the raw material inlet zone, and introducing the exhaust gas into an exhaust gas reservoir (4), and (e) producing methane and methanol in a methanation reactor or methanolation reactor from carbon dioxide which is supplied from the exhaust gas reservoir to the reactor, and hydrogen which is supplied to the reactor. An INDEPENDENT CLAIM is also included for a shaft furnace plant (1) for producing quick lime, cement, dolomite or magnesia, and for carrying out the above method, comprising a shaft furnace device which comprises the shaft furnace, at least one exhaust pipe (3) from shaft furnace inlet to an exhaust gas reservoir, at least one exhaust gas reservoir, at least one methanation- or methanolation reactor, at least one methane- or methanol storage (10), at least one water electrolysis plant operated with water and electricity, and at least one exhaust pipe from the exhaust gas reservoir to the combustion zone and/or the outlet zone of the shaft furnace.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic representation of the shaft furnace plant.    Shaft furnace plant (1)    Shaft furnace (2)    Exhaust pipe (3)    Exhaust gas reservoir (4)    Methane- or methanol storage (10)