In the whole coal industry, crushing is a very important step for coal preparation and primary processing. Because of its impact on sales and later investment, it is linked to the economic benefits of coal enterprises. The improvement of coal preparation technology and the further development of market economy have put forward new requirements for traditional coal sizer operations, which are mainly reflected in the following aspects:
1.Requirements of washing equipment: Different washing equipment has different processing particle size range, must be broken to meet the requirements of washing equipment.For example, the heavy medium cyclone is widely used because of its high sorting efficiency and strong adaptability, and its production is easy to automate. But if the washing product particle size exceeds the limit, it is easy to cause the plugging phenomenon, so that it can not play an efficient role, the operation of coal sizer can strictly ensure the feeding particle size to solve this problem.
2.Market requirement: Coal users have very strict requirements for product granularity, and different users have different requirements for granularity that constantly change with the market. If the requirements are not met, it will lead to unsalable coal or customers refuse to pay for goods due to granularity exceeding the limit, which will directly affect the economic benefits of coal enterprises. Moreover, at different times, the prices of products with different particle sizes and specifications are different, and enterprises must rely on effective operations of coal sizer to obtain maximum profits. 3.Reducing the over-comminution in crushing process: the over-comminution in crushing process will not only cause the waste of resources and affect the economic benefit of coal enterprises, but also lead to the increase of water content of coal slime system pressure and the decrease of the actual yield of gravity separation cleaned coal. Reducing the amount of pulverized coal to a minimum in the case of environmental protection requirements and the increase of pulverized coal treatment costs becomes the key to operation of coal sizer.
4.The requirement of Coal deep processing and clean: in the process of washing and processing should be carried out on coal crushing operation effectively, to maximize coal gangue monomer dissociation, increasing the specific surface area of raw material, improve the quality of coal (lower ash content, higher calorific value), remove the harmful material such as sulfur, phosphorus in the coal, decrease air pollution resulted from the coal combustion.
5.The requirement of Energy conservation: The production cost of crushing and grinding operation in the concentrator will account for more than 40% of the total dressing cost, and the investment cost of these equipment will account for about 60% of the total investment in the concentrator. Although the production cost and capital construction investment of crushing operation of coal preparation plant are lower than that of concentrator, the production cost and capital construction investment of preparation system have relatively great influence on the technical and economic indicators of coal preparation plant.Therefore, it is of great significance to reduce crushing power consumption and improve coal sizer productivity.