Zenith Crushing Plant Finely Ground

In Fig. 3 the traveling grate machine is the same as that shown to the right of drying drum 12 in Fig. 1. Fig. 3, however, shows different apparatus for preparing the pellets to be charged on the grate of the traveling grate machine. Each element of apparatus in Fig. 3 corresponding or similar to an element of apparatus in Fig. l is designated by the same reference numeral with the sufiix a added.

The main difference between the apparatus shown in Figs. 1 and 3,zenith crushing plant is that means are provided in the apparatus of Fig. 3 for forming pellets by coating balls of iron ore with a layer of solid fuel instead of admixing fuel with the iron ore and subsequently forming pellets as done with the apparatus shown in Fig. 1. It has been found by experiment-that pellets containing hematite burn to a harder consistency when the fuel is on their surface than when the fuel is distributed throughout the pellets. The fuel for coating the iron ore may comprise finely ground coke or anthracite passing through a two hundred mesh screen, but finer ground coal adheres better to the surface of the ore.

In Fig. 3, a hopper 3a supplies finely divided concentrated iron ore, and suitable feeding means (not shown) supplies ore at the desired rate to an endless belt conveyor 7a which delivers the oreto a balling drum 1a. Balls are formed most efficiently in balling drum 1a when the moisture content of the ore is between 8 and 11 percent. A water pipe 109 is provided for adding water to raise the moisture content to that amount, if necessary. Balls formed in balling drum 1a are preferably formed in sizes between one quarter and three quarters of an inch in diameter although some variation beyond these limits is permissible. Formed balls from balling drum 1a are discharged to a shaking screen 80 from which balls of suitable size are delivered to a rotatable coating drum 101. Undersized balls are returned to the feed end of balling drum In via endless belt conveyors 9a, 10a...