The Particle Collision Analysis Of Semi-autogenous Mill Based On The EDEM

Semi-autogenous mill is the key equipment in mines grinding operation at present, with the advantages of short technological, low investment and operation, and large throughput, its status has been gradually moving beyond the traditional ball mill in mines. Semi-autogenous mill are the same as ball mill, belonging to the tumbling mill, and its grinding mechanism has many similarities with ball mill, such as the shortcomings of the high energy consumption and low efficiency. For a long time, many scholars are set out to the movement of ore and steel ball in mill to research the grinding mechanism of the semi-autogenous mill, forming a lot of ore and ball movement theories, but because of the complexity of the milling system, it still cannot explain the grinding mechanism of the semi-autogenous mills clearly.On the basis of investigating and surveying the production practice of semi-autogenous mill, the trend of domestic overseas optimization and improvement in throughput, selecting the two most common optimized parameters in production practice:feed particle size and ball load, researching on an Φ10.377m×5.19m semi-autogenous mill of the mammoth mill in our country, the three-dimensional simulation of the semi-autogenous mill was established which considering feed end and discharge end, and verifying the three-dimensional simulation. Starting from the particle collision in semi-autogenous mill and broken theory of ore, four groups of different sizes of valuesin was selected in the view of two parameters, processing a total of 16 groups of all combination EDEM simulation. Firstly, the transformation of feed particle size and ball load was analyzed due to five different collision energy as its target, preliminary analyzing the semi-autogenous mill’s energy utilization efficiency; Then through the analysis of ore impact velocity and impact specific energy, on the basis of the ore broken mechanism, researching the collision circumstance in semi-autogenous mill, and using it to explain the grinding mechanism of the semi-autogenous mill.Through the researches we found that the effective collision energy occupy about 66%-77% of the sum of five collision energy in semi-autogenous mill, the effective collision energy will increase with the decrease of the feed particle size and the increment of the ball load, which can provide certain theoretical basis for mines throughput optimization. The collision velocity of ore in semi-autogenous mill is mostly very small, about 83%-93% is less than 0.5m/s; and the average collision velocity of ore is about 0.2m/s, while the maximum collision velocity of ore is 12m/s. The distribution of the ore collision specific energy is similar to the collision velocity of ore in semi-autogenous mill, most of the collision specific energy is very small, the probability of ore come up to body broken is very small, which are even negligible, therefore, the semi-autogenous mill’s grinding is giving priority to the surface rupture to ore with low energy collision, and the grinding strip occupy the most of energy in semi-autogenous mill, which leads to a lot of energy are missing with thermal, and also is the root cause of semi-autogenous mill’s high energy consumption and low efficiency.