Φ6×3m SAG mill (first stage) and Φ4.27×7.3m overflow ball mill (second stage)
Φ6×3m constant speed SAG mill (first stage) and Φ4.27×7.3m overflow ball mill (second stage) is applied to crush and separate gold ore in mining processing factory of Dulan Jinhui Mining Co., Ltd. Protodikonov's Hardness of ore is f=10-12, feeding material size is small, and 80-120mm material covers about 18% (see Fig. 1). Max. diameter of milling balls in the two kinds of mills is Φ120mm. All materials of mill liners are HMCB02, and the structure of mill end liners are all segmentation design of two loops. For the SAG mill, overflow type for discharging minerals, and cylinder liners are designed as the spacing configuration of high & low rectangular lifting bars. The rated output per hour of each mill is 100ton/h, and the actual output per hour of each mill reached 91.6 ton/h, now the output per hour of each mill is 65ton/h. We found that cylinder liners in the high lifting bars places are worn seriously after running for 45 days (see fig. 2). The electroacoustic system reflected the sound of milling is heavy (electro-acoustic output signal is 4mA). For the Φ4.27×7.3m overflow ball mill, the working faces of cylinder liners are designed as a geometric shape with a single wave peak. The thickness of the wave peak is 116mm, and the thickness of the wave valley is 50mm. The difference between wave peak and valley is 66mm. The electroacoustic system reflected the sound of milling is clear (electro-acoustic output signal is 11mA). So for SAG, wearing speed and conditions of liners are abnormal, and output per hour of each mill cannot reach the requirement, and milling sound is abnormal. And for the overflow ball mill, the milling sound is also abnormal.
SAG Mill - based on the detailed condition on-site, the CIC designed the lifting bars of cylinder liners to high trapezoid(see fig. 3 & 4), in order to effectively lift medium in the mill and guide the milling balls to be thrown on the working faces of material enrichment area on the bottom of the mill and achieve high-efficiency crushing of feeding material. The optimized plan can dramatically prolong the service life of mill liners, decrease output per hour (successful examples: Φ6.4×4.88m SAG in Tonghua Corporation Xinqiao Mining Co., Ltd and Φ7×3.5m SAG in Jiangtong Corporation Yinshan Mining Co., Ltd.). For the mill end liners, we designed them as segmentation structures in three loops (see Fig. 5). Actual running experience shows that mill end liners in the inside loop are all not needed to replace after being applied to our optimized design plan (successful example, Φ6.4×4.88m SAG in Tonghua Corporation Xinqiao Mining Co., Ltd.).
Overflow ball mill - base on the features of the ore and sufficiently play the grinding function of overflow ball mill, we suggested the size of main milling balls is Φ80mm, and designed the liners as double wave peaks (see Fig. 6) and the difference between wave peak and valley is 50mm. Meanwhile, the CIC designed the end mill liner as a segmentation structure in three loops in order that decreases the weight of residual scrapping end liners in the inside loop (successful example, Φ4.27×6.1m overflow ball mill in Fengyuan Molybdenum
Industry Co., Ltd.).