AGH Akademia Górniczo-Hutnicza
The main aim of the paper was a comparison of various mobile and fixed (stationary) circuits with the material recycle stream (closed) and without it (open circuits) applied in production of mineral aggregates from different rock raw materials. In the second chapter there was presented a detailed analysis of following chosen circuits: mobile circuit with an impact crusher producing lime aggregates (Fig. 1), mobile circuit with a jaw crusher cooperating with a fixed three-stage circuit applied in quartz aggregate production (Fig. 2 and 3) and fixed two-stage circuits with impact and cone crusher, producing dolomit aggregates (Fig. 4a, b and c). The circuits mentioned the above were characterized with using of simplified schemes. In Chapter three a work analysis of nine circuits was made on the basis of collected data and calculated indices (Table 6). Following indices were taken into consideration: fuel and energy consumption costs, unit energy consumption, maximum size reduction ratios, and the index which is the product of energy consumption and maximum size reduction ratio at single comminution of 1 tonne of feed. It was concluded that the most appropriate method of comparison of different devices is presentation of energy consumption values in joule units. When analyzing the mineral aggregates production processes in the above circuits it was concluded (Chapter three and four) that the application of multi-stage comminution and classification circuits, especially with material recirculation streams, is the most favourable in terms of the energy consumption. The most favourable installation appeared the two-stages closed circuit with shaft impactors and hammer mills with screens (Fig. 4c). It was emphasized that application of circuits with the material recirculation enables the control of comminution process run through re-crushing of the screening oversize product which leads to better quality aggregates. The article also highlighted the advantages and disadvantages of mobile and fixed comminution circuits.
analiza porównawcza; przesiewanie i kruszenie
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