Circuit balling drum

In a recent quantitative comparison [32] of iron ore balling drum and disc circuits, using the two systems operating in parallel in the same plant with... 

M. Cross, Mathematical model of balling-drum circuit of a pelletizing plant, Ironmaking Steelmaking, No. 3 (1977) 159—169. 

O. Lofgren, C.-G. Nilsson and R. Odman, Operational experiences on balling circuits with drums, discs, and roller seed screens, in K.V.S. Sastry (Ed.), Agglomeration 77, AIME, New York, 1977, pp. 425-435. 

ASTM tumbler test, 36 balling circuit control, 75 balling drums, 78... 

While many of these and newer plants are still using balling drums, quite a few of the later installations employ the balling disc to eliminate the need for large closed-circuit recycle loops. 

Figure 107. Typical balling drum circuit for iron ore pelletizing ...

Sufficient nuclei must be produced in the drum at all times to replace the pellets that are removed from the circuit, and the growth rate per pass must be such that the required production capacity of green balls is consistently maintained. Therefore, the rate of pellet production must be stabilized and the balance between material in the drum and recycle rate must be kept constant. Nevertheless, balling drum circuits tend to surging the reasons for this are only recently beginning to be understood. 

More information on balling drums and circuits, their design, and operation can be found in the literature. ... 

Fig. 6.8-17 I sometric drawings of the three major iron ore pelletizing processes [B.48, B.97], a) Balling drum circuits with shaft furnaces, b) Balling drum circuits with straight travelling grate machine, c) Balling drum circuit(s) or balling pan(s) with grate-kiln hardening system...

Fig. 6.8-5 Typical balling drum circuit for the agglomeration of fine iron ores [B.48] Fig. 6.8-6 Diagram of the optimum charge movement in a balling drum [B.18]...

In the overall cost comparison (items 1—4 above), the balling disc circuit was only about 2% lower in cost than the drum circuit. This difference was considered not to be significant and it was concluded that the choice between the two types of circuits must be made on other factors, including personal choice. 

As alternatives to the closed-loop balling circuit (see Section 4.2.1.3.5) there have been several proposals to achieve classification in the drum by various internal designs. For example, a multiple-cone drum pelletizer was described. 

Fig. 6.8-4 Tumble/growth agglomeration equipment for the balling of iron ores. (Left) Diagram of a) the disc (pan), b) the cone, c) the drum (including recirculation circuit). (Right) Actual equipment (c drum only) (courtesy Feeco, Green Bay, Wl,...

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