Energy Efficiency Grinding Circuit Optimization
The Mount Isa copper concentrator started operation in 1973. Its secondary grinding circuit consisted of two 5 meters diameter ball mills in closed circuit with 505 mm cyclones. At the design throughput of 800 t/h, the 80% passing size of the circuit product (P80) was about 140 μm.The then Mount Isa Mines Limited (MIM) installed two autogenous grinding (AG) mills in 1991 to replace two stages of crushing, a rod milling stage and one primary ball milling stage. One of the AG mills was later converted to semi-antogenous grinding (SAG) operation by the addition of a steel grinding medium to achieve the designed plant throughput of 800 t/h. The cyclone overflow P80 of the secondary ball mill circuit was reduced to 120 μm by the increased operating power in the AG/SAG mill circuits. The two secondary bails mills had a grinding power of 5.2 MW. A mineralogical study of the milled products indicated that half of this grinding power was sufficient for adequate chalcopyrite liberation. Eliminating one of the secondary ball mills could reduce energy and operating costs by more than A$2 million dollars per year.An optimisation project team was established to achieve the predicted power saving. Grinding circuit simulations were conducted for different circuit configurations. Ball mill parameters such as ball size, ball charge and feed slurry density were optimised. Cyclone body diameter, spigot and vortex finder sizes, and cyclone types were tested. The secondary ball mill circuit was redesigned and several proposed circuits were run as trial production campaigns to determine their operability and efficiency. The plant trials confirmed that one of the secondary ball mills could be decommissioned. Significant cost savings were achieved as a result.The success of the project demonstrates optimising grinding circuits can not only deliver the plant performance, but also a much lower unit operating cost through energy and maintenance savings.
Grinding circuit Ball mills Cyclones Copper concentrator Mount Isa Mines Energy efficiency Cost saving
M. W. Gao C. Fountain M. Magee D. Way
Ausenco Services Pty Limited, Australia Xstrata Copper, Australia
国际会议
XXIV International Mineral Processing Congress(第24届国际矿物加工大会)
北京
英文
283-289
2008-09-24（万方平台首次上网日期，不代表论文的发表时间）