Page 114 - Fundamentals of Air Pollution

84 6, Sources of Air Pollution

Fig. 6-8. Flow diagram for a phosphoric acid plant.

E. Soaps and Detergents
Soaps are made by reacting fats or oils with a base. Soaps are produced
in a number of grades and types. They may be liquid, solid, granules, or
powder. The air pollution problems of soap manufacture are primarily
odors from the chemicals, greases, fats, and oils, although particulate emis-
sions may occur during drying and handling operations. Detergents are
manufactured from base stocks similar to those used in petroleum refiner-
ies, so the air pollution problems are similar to those of refineries.

F. Phosphate Fertilizers
Phosphate fertilizers are prepared by beneficiation of phosphate rock to
remove its impurities, followed by drying and grinding. The PO 4 in the rock
may then be reacted with sulfuric acid to produce normal superphosphate
fertilizer. Over 100 plants operating in the United States produce approxi-
mately a billion kilograms of phosphate fertilizer per year. Figure 6-9 is a
flow diagram for a normal superphosphate plant which notes the pollutants
emitted. The particulate and gaseous fluoride emissions cause greatest
concern near phosphate fertilizer plants.

G. Other Inorganic Chemicals
Production of the large quantities of inorganic chemicals necessary for
modern industrial processes can result in air pollutant emissions as undesir-
able by-products. Table 6-2 lists some of the more common inorganic chemi-