Flow diagrams nitric acid production

A qualitative flow diagram indicates the flow of materials, unit operations involved, equipment necessary, and special information on operating temperatures and pressures. A quantitative flow diagram shows the quantities of materials required for the process operation. An example of a qualitative flow diagram for the production of nitric acid is shown in Fig. 2-1. Figure 2-2 presents a quantitative flow diagram for the same process. 

Wet Process Phosphoric Acid. A production process flow diagram is shown in Figure 8. Insoluble phosphate rock is changed to water-soluble phosphoric acid by solubilizing the phosphate rock with an acid, generally sulfuric or nitric. The phosphoric acid produced from the nitric acid process is blended with other ingredients to produce a fertilizer, whereas the phosphoric acid produced from the sulfuric acid process must be concentrated before further use. Minor quantities of fluorine, iron, aluminum, sUica, and uranium are usually the most serious waste effluent problems. 

Figure 2 shows a simplified process flow diagram for halogenated aliphatic acid production facilities [8]. Halogenated aliphatic acids include chlorinated aliphatic acids and their salts, for example, TCA, Dalapon, and Fenac herbicides. Chlorinated aliphatic acids can be prepared by nitric acid oxidation of chloral (TCA) or by direct chlorination of the acid. The acids can be sold as mono- or dichloro acids, or neutralized to an aqueous solution with caustic soda. The neutralized solution is generally fed to a dryer from which the powdered product is packaged. 

The two important modern weak nitric acid (60-68% by weight) production processes which have been developed are the dualpressure process and single-pressure process. The dual-pressure process was developed and used mainly in Europe, whereas the single-pressure process (developed by Du Pont) is common in the USA. Both processes are capable of highly efficient production of the same quality product, with the same limits on atmospheric pollution. The process flow diagrams for the dual-pressure process and the single-pressure process are presented in Figures 3.1 and 3.2 respectively (Ref. PTI pp.176,177). 

Net realizable value, definition of, 333 Nickel and alloys, 431, 438, 440-442 Nitric acid, flow diagram for production of,... 

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