Applications of Phosphorus Compounds

In addition to the route via phosphoric acid, bones constitute a natural biosource of the highly important calcium phosphates. Industrially produced natural products such as casein and lecithin are also alternative sources of some phosphorus compounds (Fignre 12.2). They have a growing nnmber of applications in food products and many other areas. 

The bulk of manufactured phosphoric acid is used, either directly or indirectly, for fertilisers (Section 12.2). Much of the remainder is used for the production of phosphorus chemicals, but the acid itself has various important direct applications, particnlarly in the surface treatment of metals (Section 12.7). 

FIGURE 12.1 Main industrial routes to phosphorus chemicals. 

The commercial production of orthophosphates and polyphosphates, particularly the sodium, ammonium and calcium salts, together with phosphoric acid, greatly exceeds that of aU other compounds of phosphorus. The lion s share of these is used by the fertiliser industry, but detergents, animal foodstuffs, metal treatments and human food products are also major consumers. 

---