| The principle of "more crushing and less grinding" is considered as an effective way of decreasing consumptions of the energy and materials in grinding and crushing, and moreover, fine crushing is thought of as a direct means with which reducing the size of mill feed and "more crushing and less grinding" are realized. The crushing product particle size could be lower than 4mm when Auto Inner Cycling Fine Crusher (ACFC) was used in fine crushing. The breakage theory and experimental parameter of ACFC are studied in detail, which is of benefit to greatly improving the throughput capacity of ball mill, less overcrushing, making full use of resources and increasing economic benefit.ACFC is a newly highly-efficient machine(The patent number is ZL96220822.1.)invented by Kunming University of Science and Technology, which adopts medium pressure and particle bed breakage and makes full use of the second crushing energy. Ore comminution in the crusher chamber that is composed of the outside surface of the small roll and the inside surface of the big roll takes place during the automatic circle movement of the ore. An ingenious device is well employed to remove the crushing product forcingly even if ore contains a great deal of water and clay.On the basis of ACFC's design and manufacture, not only theoretical study and experimental study of medium pressure and particle bed breakage, but also the studies of product size distribution and energy-consumption principle are carried out. Crushing pressure, the speed of the small roll, the gap between two rotating rolls and throughput capacity are four important parameters that affect ACFC.The results of theoretical study are 1) The ore distortion is reversible before elastic ore fractures, but the ore distortion is not reversible before plastic ore fractures. 2) Plenty of new surface area is created continuously in a short time when high pressure exerts particles. If the particles have the same new surface area, intermissive medium pressure must do it for a longer time. 3) Creation, coalesce, extension of crack are relative to energy transformation among system energy, new surface energy and distortion energy. 4) Energy efficiency in medium pressure is not as high as thatin high pressure. 5) The nip angle has a great effect on the performance and wear abrasion of high-pressure grinding roll and ACFC respectively. 6) The tangency speedof the ore locomotion is calculated as follows: Vt = . The average shaft speed iscalculated as follows: v = . The throughput capacity of ACFC can be calculatedby ) When the interspace quotiety of the ore falls rapidly, the crushprocess of ACFC is greatly enhanced.The crushing pressure and the speed of the small roll are the main parameters that affect the performance of ACFC through fine crushing experiments of Vanadium- Titanium magnetite ore and Platinum-Palladium sulphide ore. Considering the relationship among the abrasion of the two rolls, energy-consumptions and product size, the best parameter is that the compress pressure is 10 tons, the speed of the small roll is 231r/min. When the installation power of 800 X 400X1200 ACFC is 10KW and the capacity of ore feed reaches 11 ~ 13t/h, the energy-consumption of crushing one ton Vanadium-Titanium magnetite ore is 1 . 1 ~ 1.3KW-h.Analyzing the character of product size and energy-consumption, we can obtain four conclusions. 1) When the gap of ACFC is 4mm, the character of product size distribution is calculated as follows: y = 100e-0.003436494x0.849 . 2) When the gap of ACFC is 7mm, the character of product size distribution is calculated as follows: y = KWe-0000807264x1.0108 . 3) When the gap of ACFC is 10mm, the character of product size distribution is calculated as follows: y = l00e-0.000852738x0.9827 . 4) The Energy-consumption of crushing Vanadium-Titanium magnetite ore is calculated asfollows:...
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