Shanghai Minggong Heavy Equipment Co., Ltd0

The effect of Ball Mill Charge Pressure and Impact on Grinding

新闻稿   •   2012年07月06日 16:15 CST

The Ball Mill is made up of feeding part, discharging part, gyre part, transmission part(inclding decelerator, small transmission gear, generator, electrical control) and so on. The hollow axis adopts the cast steel and the lining can be replaced, the rotary big gear is processed from cast rolling gear. The barrel body is wearable well and bears wearable scaleboard. So this machine runs steadily and works reliably.
The actual comminution of the material is as result of the pressure exerted by the grinding media and the impact generated by the weight and movement of the charge.
At every phase of grinding operations, there should be a balance between the comminution resulting from pressure and that resulting from impact.
In primary mills, large particles of feed material are crushed by impact. A minimum size of grinding body is needed to generate the required impact. However, this means that a small number of large grinding bodies occupy a large proportion of mill volume. The degree of medium and fine grinding is reduced, and mill throughput is low.
Smaller grinding bodies can be used if their kinetic energy can be increased through greater drop height. This can be achieved by installing higher lifter bars, as shown in figs. E65 and G65.
A comparison of these two pictures shows that the grinding bodies drop off the lifter bars at a greater height in Fig. G65, in which the toe of the charge is also thinner. This indicates that total droop height has increased and that impact force is consequently greater.
The pressure within the charge is very uniform in both cases. Figs. F65, F75 and F85 illustrate how charge pressure decreases as mill speed is increased.
The quantity of grinding bodies is identical in each of these illustrations, although the charge level appears to be higher in F85.
The liner plate profile affects the relative movement of the grinding bodies. This in turn is another important factor with respect to the utilization of mill capacity. Get beneficiation,Mineral Processing,ball mill From http://www.ballmill8.com

Direct Preferential Flotation
Definition of this method is: separate various helpful minerals in proper order. With its feature of high flexibility, it can adapt the change of ore grade, especially for sulphide ore of high grade. Xilin, Fankou, Lechang lead-zinc dressing plant of our country, and Laisvall lead-zinc dressing plant of Sweden all adopt this method.

Combined Flotation Flowsheet
Firstly, get mixed concentrate through the emersion of all useful minerals in ores; secondly, separate various helpful minerals in sequence from mixed concentrate. These two steps together are called part of amalgamate flotation Flowsheet. This process is suitable for treat raw ores of complex structure, fine embedded grains, and low content of sulfide mineral, which are in close symbiosis relationship. Because this process can simplify process, reduce ores’ over grinding, so as to benefit separation. Almarc Lead-zinc plant of former Soviet Union adopts preferential flotation this process. By using this process, we can get higher index than preferential flotation improve 10% of lead concentrate ore grade and 4.5% of zinc concentrate ore grade, raise the rate of multipurpose utilization from 75.4% to 83.7%, and double labor productivity. Qingchengzi zinc-lead ore dressing plant and Xiaotieshan copper ore dressing plant of our country adopt this process.

Part of Amalgamate Flotation Flowsheet
We can get mixed concentrate by the emersion of two useful minerals in ores together, then separate single concentrate from the mixed concentrate. The two stages together are called part of amalgamate flotation Flowsheet, which is the most widely used process in production. It is quite economical to adopt this process when raw ores contain low-grade nitrogen, copper-lead, copper-zinc, and lead-zinc.

Iso-flotability Flotation Process
According to minerals’ flotability in ores, mineral assemblages of good, medium and worse flotability are separated through flotation separation. Secondly, different helpful minerals are selected out from all mixed concentrates, which is called iso-flotability flotation process. For example, Huangshapinng lead-zinc ore dressing plant of our country, and Zheskaz of former Soviet Union both adopt this process. beneficiation,Mineral Processing,rotary kiln http://www.dryballmill.com