SELECTION OF WET PROCESS

SELECTION   OF   WET   PROCESS

[By H2S04 Leaching]

1) Now a days both the phosphoric acid production method is in side use but the wet      process will probably predominate because of fertiliser requirement.

2) Phosphoric acid (about 93%) is mostly used for fertiliser production. On the other hand only 20% phosphoric acid of electric furnace process is used for fertilizers.

3) The cost of the plant in electric furnace process is higher as compared to wet            Process. A capital investment of Rs. 600 per annual tonnes is required for wet. Process where as it is Rs. 1000-1200 per annual tone for an electric furnace plant.

4) Gypsum a byproduct of wet process (H₂S0₄ leaching) is a useful material. It can be used as it is or can be converted into ammonium sulphate which can be used as Fertilizers.

          (NH₄)₂C0₃    + CaS0₄                (NH₄)₂S0₄   + CaC0₃

          Whereas the byproduct of electric furnace process slag carbon dioxide and           Phosphorous are practically used.

5)        Sulphuric acid generally obtained from sulphur. Sulphur and its compound like S0₂, S0₃ are present in many rocks, which can be readily converted into sulphuric acid, sulphuric acid is readily available nearer to plant as compared to the HCI acid. Also phosphate rock contain SO which may be converted into H₂S0₄ acid & as sulphuric acid cheaperer than HCI acid also transportation is less costly. SO we select wet process by H₂S0₄ leaching.