A process container comprising a metallic casing having at least one refractory cladding layer disposed on the inner side thereof, and cooling elements connected to the outer side of the casing. Each cooling element comprises a base plate and at least one cooling channel connected to the base plate in a heat-conducting manner. The base plate is connected to the outer side of the casing by being screw connected to threaded bolts welded onto the outer side of the casing whereby the base plates nestle against the casing by flexural deformation due to clamping pressure of the screw connections. Ends of the cooling channels are connected to ends of adjacent cooling channels.