RAW MATERIAL FOR H3P04:-

RAW   MATERIAL FOR H₃P0₄

Two   types of raw    material are used in the production of   H₃P0₄   as   phosphatic   rocks   and   sulphur.

1] Phosphate rock:-

In 1981 the world phosphate rock production was estimated to be 138 million tones of commercial ore. Phosphorous is the 11th most frequent element in the earth crust sealimentary deposits are the most important for phosphate rock production. Sealimentary rock contains more carbonates and fluorides and usually more iron and aluminium. May present as a porous material and offer surface for a chemical reaction. Most of the time they contains organics which are responsible for coloring and foaming that occurs in acid and finished product.

MINING AND BENEFACTION

To bring the phosphates rock on to international market. The ore has to mined concentrated and transported to nearest port from where it is shipped to H₃P0₄ plant.

Mining is done either by open cast mining   or underground   mining. To produce H₃P0₄ main criteria for phosphates ore are:

 1) P₂0₅ content: When above   33% to   38% P₂0₅ considered    as    high    gread.

2) CaO content: Affects  the     H₂S0₄  consumption. Relatively  pure   acid   can  be producefrom ore containing    very large amount of   calcite.

3) Fluorine: It can be  corrosive component   if not   enough  reactive silica is    also present.

4) SO_3: Only  dead    wt.    The existing    S0₃   in phosphate  rock       will   save the corresponding   amount   of   H₂S0₄ during acidification.

5) Chlorine:   Undesirable  impurity because of corrosion      damages.

6) Al₂O₃ and: Problems    when      using     H₃PO₄  sludge formation    with' cone.   

    Fe203 acid.

7) MgO:  Increase    viscosity    strongly.

8)  Organics: Foaming    during    reaction      dark    cloudy, solid, suspended    in    product    acid.

9) Sulphur:    Besides phosphates rock sulphur by means of sulphuric acid is the second raw material need for phosphoric acid production wet process phosphoric acid is the major world sulphur consumer with nearly 50% of total production sulphur is produced from brine stone purifies and other forms. The prices of the world sulphur are all from production consequent strongly affecting acid economics.