Apparatus for mixing

Apparatus for mixing of a chemical medium in gaseous or liquid state with a pulp suspension, comprising a housing having a wall that defines a mixing chamber, a first feeder for feeding the pulp suspension to the mixing chamber, a rotor shaft that extends in the mixing chamber, a drive device for rotation of the rotor shaft, a rotor body that is connected to the rotor shaft and arranged to supply kinetic energy to the pulp suspension flow during rotation of the rotor shaft by the rotation of the drive device, such that turbulence is produced in a turbulent flow zone in the mixing chamber, a second feeder for feeding the chemical medium to the mixing chamber, an outlet for discharging the mixture of chemical medium and pulp suspension from the mixing chamber, a flow-restraining disk in the outlet from the mixing chamber with one or more flow passages arranged to temporarily increase the flow velocity of the pulp suspension when the pulp suspension passes the flow-restraining disk, the second feeder comprising a chemical distribution element integrated with the rotor body and arranged to distribute the chemical medium to within a close vicinity of said turbulent flow zone and said rotor body comprising a number of rotor pins which extend from the rotor shaft on the upstream side of the flow-restraining disk.