Page 362 - Centrifugal Pumps 2E

Chemical Pumps Metallic and Nonmetallic 327

Sodium Chlorite—Na CIO 3

This is used for bleaches, herbacides, explosives, and rocket fuels.
Pumps can be in 316 or nonmetallic.

Pulp and Paper

Sulfite process: usually acids and bleaches. Sulfate (which is Kraft) is
used in making strong cardboard containers and wrappings. Usually use
titanium or vinyl ester pumps.

Metal Finishing
Electronic plating, cleanings such as oil, rust, and scale. Usually use
ductile iron pumps. Plating usually use nonmetallic pumps to prevent
stray currents. Waste treating of the vent plating baths are usually 316 or
eonmetallic pumps.

Carbon Steel Pickling

Sulfuric acid was replaced by hydrochloric acid to give a better finish.
Use 316, alloy 20, or nonmetallic pumps.

Stainless Steel Pickling

Nitric hydrofluoric acid solutions process is not suitable for nonmetal-
lic pump application.

Oesalinization and Water Purification

Desalinization and water purification are done through distillation or
reverse osmosis. Usually a simple plant used for marine or power plants
is used for distillation. The size of the plant can be scaled up or down. It
can tolerate a wide latitude of feeder water quality, but requires high tem-
peratures and results in more corrosion and more maintenance. It is usu-
ally only efficient using low pressure steam. The temperature is from
70° to 250°F with a vacuum as low as 25 inches of mercury. The pumps
are usually 316 or alloy 20.
The reverse osmosis process using a membrane is simple, compact,
more efficient, and uses ambient temperature. The membranes are sensi-
tive to metal pick ups. It can purify dirty well water, brackish water with
200 to 600 psi. If it is used for desalinization of salt water, the pressures
are from 800 to 1000 psi. Miscellaneous pumps can either be 316 or non-
metallic.