The ribbon blender comprises of a U- shaped horizontal trough, specially designed double helical ribbon agitator, rigid fabricated structure motor gear box, in operation, material is filled to top of the outer ribbon. the shaft rotates at relatively low speed and the moving ribbons the material back and forth mixing it. the outer ribbon rotation displaces the material from the end to the center to the ends. This counter-cureent action results in homogenous blending. Mixing is achieved15to 20 minutes with 90 to 95%or better homogeneity. The bottom discharge is provided for unloading of the material and easy cleaning of the mixing drum. Specially designed self adjusting sealing arrangement of unique design is provided to ensure that no black particle center into the mixing drum.