ABSTRACT
The Sackett Super-Flo process for the continuous manufacture of superphosphates was introduced to the fertilizer industry in the late 1940s, with the installation of two mid-western operations. Excess air then left the tower through the bottom and into the housing of the next part of the process unit, the puddler, which was exhausted by the scrubbing system. The puddler was under a negative pressure, since it was necessary to exhaust SiF4 and CO2, which were flashed after contact of acid and rock. By the time the material had left the puddler, it had a consistency which was just barely self-leveling. The idea that Sackett had for the initial contact of rock and acid in the acidulating tower was valid, and one can see in retrospect that if the flow of the two basic materials had been interchanged the acidulating cone could have been invented ten years before it was.
