Abstract: The ball valve, especially for a solvent-containing flow and/or an abrasive solid mixture, has a housing, a sintered ceramic valve seat, a sintered ceramic valve ball and an operating shaft for the valve ball guided through a shaft seal in the housing. The valve ball is positioned free of an elastic seal between seating surfaces of the valve seat and the valve seat has at least two sintered ceramic seat rings which are mounted in the housing and which are acted on with a pressing force by an elastic element supported in the housing. The valve ball is positioned between the seat rings which seal on the housing and are acted on with a sealing force. The seat rings have a plurality of seating surfaces which are formed like the surface of an inner core and contact tangentially on the valve ball along circumferential sealing lines.