A drum coater for applying a surface layer on bulk-like materials includes a rotatably mounted drum for accommodating bulk-like materials, inlet and outlet openings, at least one spray nozzle for applying the surface material, a drying device for a drum interior, at least first and second radially-offset mixing tools in the drum, the first mixing tool protruding into the drum interior. The at least one second mixing tool has at least one mixing surface such that the first mixing tool is at least partially arranged on the drum inner surface and the at least one second mixing tool has at least one opening on the at least one mixing surface. A mixing tool to be used in a drum coater to gently blend and/or homogenize bulk-like materials has a first mixing surface angled relative to a second mixing surface, at least one mixing surface having at least one opening.

A roasting drum has a main body and at least one opening formed through the main body. The main body has a first end, a second end opposite the first end, and multiple drums. The multiple drums are mounted around one another in sequence, are fastened to one another, and communicate with one another. Each one of the multiple drums has a blending blade formed on an inner surface of the drum. The blending blade is spiral and extends from the first end toward the second end. The blending blade of one of the multiple drums twists along a clockwise direction from the first end toward the second end. The blending blade of another one of the multiple drums that is mounted around the drum twists along a counter-clockwise direction from the first end toward the second end.

A roasting drum has a main body and at least one opening formed through the main body. The main body has a first end, a second end opposite the first end, and multiple drums. The multiple drums are mounted around one another in sequence, are fastened to one another, and communicate with one another. Each one of the multiple drums has a blending blade formed on an inner surface of the drum. The blending blade is spiral and extends from the first end toward the second end. The blending blade of one of the multiple drums twists along a clockwise direction from the first end toward the second end. The blending blade of another one of the multiple drums that is mounted around the drum twists along a counter-clockwise direction from the first end toward the second end.

A drum coater for applying a surface layer on bulk-like materials includes a rotatably mounted drum for accommodating bulk-like materials, inlet and outlet openings, at least one spray nozzle for applying the surface material, a drying device for a drum interior, at least first and second radially-offset mixing tools in the drum, the first mixing tool protruding into the drum interior. The at least one second mixing tool has at least one mixing surface such that the first mixing tool is at least partially arranged on the drum inner surface and the at least one second mixing tool has at least one opening on the at least one mixing surface. A mixing tool to be used in a drum coater to gently blend and/or homogenize bulk-like materials has a first mixing surface angled relative to a second mixing surface, at least one mixing surface having at least one opening.