1,1 Applications of Slurry Transport Vast tonnages are pumped every year
in the form of solid-liquid mixtures, known as slurries. The application
which involves the largest quantities is the dredging industry,
continually maintaining navigation in harbours and rivers, altering
coastlines and winning material for landfill and construction purposes.
As a single dredge may be required to maintain a throughput of 7000
tonnes of slurry per hour or more, very large centrifugal pumps are
used. Figures 1-1 and 1-2 show, respectively, an exterior view of this
type of pump, and a view of a large dredge-pump impeller (Addie &
Helmley, 1989). The manufacture of fertiliser is another process
involving massive slur- transport operations. Li Florida, phosphate
matrix is recovered by huge draglines in open-pit mining operations. It
is then slurried, and pumped to the wash plants through pipelines with a
typical length of about 10 kilometres. Each year some 34 million tonnes
of matrix are transported in this manner. This industry employs
centrifugal pumps that are generally smaller than those used in large
dredges, but impeller diameters up to 1. 4 m are common, and drive
capacity is often in excess of 1000 kW. The transport distance is
typically longer than for dredging applications, and Chapter 1 Figure
LI. Testing a dredge pump at the GIW Hydraulic Laboratory Figure 1. 2.
Impeller for large dredge pump 1. Introduction 3 hence a series of
pumping stations is often used. Figure 1-3 shows a boost- pump
installation in a phosphate pipeline.
