Abstract: A structure of a tank for storage of a suspension is improved in that a conical bottom partition wall is disposed in the bottom portion within a cylindrical outer shell of the tank with its lowest point located substantially at the center of the horizontal cross-section of the cylindrical outer shell. An upwardly extending side wall is provided along the circumference of the conical bottom partition wall and is disposed with an appropriate interval spaced from an inner surface of the cylindrical outer shell. A cover consisting of an annular top wall inclined substantially in parallel to the conical bottom partition wall and a downwardly extending side wall is fixedly secured to the inner surface of the cylindrical outer shell so as to cover the upwardly extending side wall with an appropriate interval spaced therefrom.