|
We have never subscribed to the idea that the hammermills is suited to the primary breaking of shovel-loaded, quarry-run, or mine-run rock and ore. Even though the material be nonabrasive and quite friable there are other machines which are better fitted for such work. N or do we believe that the hammermills has a place in any of the stages of a plant intended for the production of commercial crushed stone unless the production of a high percentage of fines is not objectionable-a rather rare condition for operations of this character.
These legitimate restrictions still leave quite a broad field for this machine, and it is probable that more applications will crop up from time to time as our chemical industries grow.
Examination of 33 cement plant flowsheets, published in 1922, discloses that, at that time, only six of these plants employed hammermills, and two of these were used in the shale crushing department. Today the hammermill is widely accepted as a secondary or tertiary crusher in cement plants throughout the country; and there are isolated instances where they perform the primary breaking as well.
During World War 1 the Pulverator was successfully applied to the production of manufactured sand for concrete aggregates used in the construction of a large dam in one of the eastern states. This application was made after
crushing rolls had been tried and discarded because their product ran so. heavily to flat spalls that a workable concrete could not be made with it. We mention this case as being indicative of the ability of the hammermill to cube material, even though the rock's physical structure is conducive to spalling or flaking. Subsequent installations for the same purpose have been equally successful. |
