Pumps mill discharge

DESCRIPTION MILL OIF SLURRY MILL DlUniON SOLUTION MILL STEEL BAIL CONSUMPnON OREFEED TO MILL O.S.W.TO MILL DISCHARGE PUMP MILL SUMP DILUTON SOLUTION TROMMEL SCREEN 0/SIZE SCREEN SPRAY WATER... 

In a typical copper or zinc circuit, the recirculation load can be as high as 250-350% of the new feed. The mill and mill discharge pumps must then be sized for the combination of recirculation load and new feed. 

A rod mill in an open circuit may be followed by a ball mill in a closed circuit. This is called a double-stage circuit and is often a wet process. The output from the rod mills is a slurry that contains a high proportion of coarse stones. The slurry is pumped via mill discharge pumps to a hydrocyclone. The underflow from the cyclone is then fed to a ball mill. From tiiere, the output from the ball mill is fed once again to the hydrocyclone via the pump. 

In some circuits, the rod mill discharge is fed first to the ball mill before reaching the hydrocyclone. The hydrocyclones then feed the ball mills by gravity. A set of ball mill discharge pumps may then pump the output to a second classification circuit. The ball miU discharge has its own sets of slurry pumps. 

TABLE 8-5 Preliminary Range for Efficiency versus Flow (L/s units) For Mill Discharge Pump—Rubber-Lined Version... 

Addle and Helmly (1989) measured the cavitations parameter against specifrc speed for a number of dredging pumps. Their work is represented in Figure 8-18. Tables 8-7 and 8-8 also show certain calculations for the design of mill discharge pumps. 

TABLE 8-7 Recommendations for Impeller Diameter, Speed, Specific Speed Number, and Cavitations Parameter for Rubber-Lined Mill Discharge Pumps (U.S. Units)... 

TABLE 8-9 Recommended Dimensions for a Single Stage Mill Discharge Pump (metric size example)... 

Mill discharge pumps Gravel and dredge pumps ... 

The vertical sump (Figure 8-36) complements the horizontal pump. The vertical pump is particularly suitable for floor sumps in mill discharge areas and in dealing with flotation circuits. The vertical sump pump may be supplied as ... 

FIGURE 8-38 Sump pump with single suction impeller and auger to agitate settled solids particularly suited for mill discharge floor. (Courtesy of Mazdak International Inc.)... 

Abulnaga, B. E. 2001. Recommendations for the design of mill discharge slurry pumps. Mazdak International Inc. Internal Report 02/2001 (unpublished). 

After being pulped, the nitrocotton fibres are pumped into the poacher. If the consistency is insufficiently liquid then water is added to the slurry during pumping. The beaters or mills are emptied through a discharge pipe in the base. 

The diameter of the rods is often 50 mm (2 in) but can be set by the designer of the mill. It is, however, important to separate the rods or balls from the slurry at the discharge of the mill before they enter the slurry pump. The successful separation of steel balls from the slurry involves proper design of trommels, a mechanism to catch the balls, and screens on top of the pump box. Ideally, the balls should be recycled back to the feed of the milling unit. 

The centrifugal slurry pump is the workhorse of slurry flows. Chapter 7 briefed the reader about some important slurry circuits, and it was explained that the grinding circuits consume a fair portion of the power of a concentrator. One particular pump at the discharge of the SAG, ball, or other mills is called the mUl discharge pump. Wear in these pumps is particularly harsh, leading to frequent replacement of impellers and liners, because a fair portion of the solids remain fairly coarse until recirculated back through the classification circuit. 

Miii discharge pumps for milling and grinding circuits... 

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