A copper anode furnace includes a furnace drum which can be pivoted about a horizontal axis and in which copper melt is refined into anode copper by fire refining. The furnace drum is provided with a spout for pouring out the refined copper. A sliding closure is arranged on the spout of the furnace drum. The sliding closure includes at least one stationary, fireproof closing plate and a fireproof sliding plate which can be displaced relative to the closing plate. Through the displacement of the sliding plate, the outflow out the furnace drum can be regulated or closed and therefore the outflow amount of the copper can be controlled. A drawing of slag into the casting, which reduces the anode quality, can be prevented using the sliding closure.