Abstract
Abstract A considerable portion of energy consumption and, as a consequence, operational costs in mineral processing, is associated with comminution. High Pressure Grinding Rolls (HPGR) are appealing for their energy efficiency and resulting lower operating costs. This article evaluates this technology as an alternative to the conventional fused alumina comminution route of a specific plant comprising a complex roll crushing circuit. Two fused alumina samples, called BT and TB, were submitted to HPGR (open circuit) and physical characterization (DWT, BBWI, bulk density, specific gravity) tests. In addition, simulations were conducted using JKSimMet® 6.0 software, aiming to predict the performance of a closed circuit equipment and scale-up of an industrial-scale unit. Product size distributions of the open circuit HPGR tests and closed circuit HPGR simulations were compared with the product size distribution required by the industrial comminution circuit. The required throughput was also evaluated. Results show that the alternative HPGR route provides a remarkable potential for circuit simplification, while considerably reducing the number of comminution equipments from 13 to 1, which facilitates operational control and possibly reduces operating costs.
Highlights
Comminution accounts for a significant share of energy consumption in ore processing plants and approximately 2% of the electric power generated worldwide (Abouzeid and Fuerstenau, 2009; NapierMunn, 2015)
Presented are the results of pilot High Pressure Grinding Rolls (HPGR) tests performed by Metso in 2010 on a sample obtained from the same comminution circuit with characteristics similar to those considered in this study
It must be noted that the annual average product size specification required by the TB circuit could be met in a relatively satisfactory manner by the HPGR operating in open circuit and using a specific grinding force of 3 N/mm2
Summary
Comminution accounts for a significant share of energy consumption in ore processing plants (almost 80% in certain cases) and approximately 2% of the electric power generated worldwide (Abouzeid and Fuerstenau, 2009; NapierMunn, 2015). When fed between the rollers, particles enter a pre-grinding zone and reach an area in which interparticle breakage takes place on a bed under high compression. Such transfer is characterized by particle compaction and friction, resulting in a bulk density equivalent of up to 85% of the ore specific gravity. Three key criteria have been established for the HPGR design: throughput, specific grinding force, and power consumption (Schönert, 1985). Throughput is influenced by the ore properties and equipment characteristics and may be defined by the continuity equation, represented by Equation 1 below (Morrell et al, 1997)
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