Phosphoric Acid (H3 PO4 ) Dosing in Sugar Industry | Online Calculator

Role of Phosphoric Acid (H3 PO4 ) Dosing in Sugar Process with Online Calculator


Phosphoric acid occurs in the cane juice as both soluble phosphates and in combination as protein in the cell material. But both phosphates are not participate in reaction, only the soluble phosphates take part in the reaction of defecation.

If the phosphate content is less than 200 to 300 mg/P2O in juice, it is beneficial to make additions of inorganic phosphate to raise the juice phosphate level to above 250-300 mg/kg.

The phosphoric acid added to the juice precipitates part of the colloids and coloring matter that it contains. The precipitate formed with lime is mainly Tricalcium Phosphate.

The benefits of maintaining an optimum level of phosphate in juice are as:Phosphoric Acid (H3 PO4 ) Dosing

  • Greater colloidal elimination
  • Less calcium in clear juice;
  • Faster mud floc formation, with more rapid settling;
  • Better clarification with lighter colored clarified juice.

Disadvantages of too much phosphate addition can be higher chemical costs, higher lime consumption and higher mud volume (and hence higher filter mud sugar loss).

Action Due to phosphoric Acid Addition:

The major chemical reaction is that of the Ca++ cation with the phosphate ion to form phosphate Intermediates and to precipitate tricalcium phosphate Ca 3(PO4)2.

We have to know the activity of calcium and phosphate ions and how the phosphate components behave in the adsorption and absorption of organic colloids and other non-sugars.

It is after reacting with the available Ca++ and then  further with lime is one of the major reaction responsible for juice clarification. In the beginning the Ca++ ion reacts with HPO4 to form CaHPO4.  This is second order reaction & hence it is fast reaction,

Ca2++ + HPO– –4→ CaHPO4

Second stage phosphate ion reacts with free Ca ion to form the precipitate of tricalcium phosphate.  This a higher order reaction, hence takes time to complete

3Ca++ + 2PO– —4 → Ca3 (PO4)2      TriCalcium Phosphate

3 Ca (OH) 2 + 2 H3 PO4 ———- Ca3 (PO4) 2 + 6 H2O

Steps in Calculation for required quantity of Phosphoric acid to add in Raw juice:

Required Data:

  1. Crushing Rate ( M ) in T/hr
  2. Percentage of mixed juice ( P )
  3. Density of juice ( D )(Generally take 1.06 gm/ml for raw juice)
  4. Required phosphoric acid (in P2O5 Content) dosing in PPM ( R )to raw juice ( To know this analyze P2O5 content in mixed juice before addition than we can concluded to  how much dosing required to raw juice).
  5. Purity of Used Ortho phosphoric acid chemical ( H ) ( i.e Percentage of H3PO4 purity)

Calculation Part:

  1. Calculate mixed juice quantity (Q ) in Ltrs/hr.

  Formula = ( M x 1000)/ D

  1. P2O5 requirement in ( R ) Kg/hr (1ppm=1 mg/lit)

        T = ( Q x R) / 1000000

  1. Calculate P2 O5 % ( Y ) in given chemical H3PO4

2 H3PO4         →   P2O5 + 3H2O

2(3+31+64)          (2*31+5*16) + (3*2+3*16)

196                             142                       54

i.e 196 parts of H3PO4 gives 142 parts P205)

                           Y = ( H x 142)/196

  1. H3PO4 required quantity in kg/Hr      (R x 100)/Y

      Phosphoric Acid (H3 PO4 ) Calculator :

Some Related Articles:

Flocculants Used in Sugar Processing | Flocculant Dosing Calculation.

Juice Sulphitation Process | Methods of Sugar Cane Juice Sulphitation.

Concepts of Juice Defecation Process and its Mechanization.

Sugar Industry Related Important Websites | sugar Technology.

Sugar Tech | Sugar Technology related articles .

Sugar Industry Equipment Design and Drawing Online Calculations.

Thumb Rules for Sugar factory Equipment Design Sizing.


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Post Author: siva alluri

The aim of this Blog "sugarprocesstech" is Providing basic to advance knowledge in sugar process industry and providing maximum calculation regarding capacity and equipment design online calculators .

6 thoughts on “Phosphoric Acid (H3 PO4 ) Dosing in Sugar Industry | Online Calculator


    (April 4, 2017 - 1:26 pm)

    Good keep it up
    Website is useful for Sugar technologists


      (April 4, 2017 - 2:00 pm)

      thank you sir

    subhash Biradr

    (April 5, 2017 - 5:18 am)


    Brijendra singh

    (May 28, 2017 - 4:32 am)

    Very interested topic good

    Sageer Ahmed

    (April 12, 2018 - 9:27 pm)

    Very nice and much useful calculation for sugar mills.

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