How to prevent Sodium Sulfate Cryslazing in Detergent product

We use sodium sulfate in our detrgent product, but it tends to crystalize into needles. We use the sodium sulfate as a filler. How to prevent this crystalization?


  • Chemist77Chemist77 Member, PCF student
    Presence of phosphonates is mentioned as one of the reasons for crystallization, what are other components here???
  • BILOBILO Member
    The other components are in mixing sequence:
    1. Water.
    2. Caustic Soda 48%.
    3. LABSA.
    4. Sodium Silicate.
    5. Sodium Carbonate.
    6. Sodium Sulfate.
    7. Calcium Carbonate.
    8. Glycerine.
    9. Dye.
    10. Scent.
    11. Formaline.
  • Chemist77Chemist77 Member, PCF student
    why glycerin, why no binder like CMC. Nothin looks out of sort here but you can do knock outs or replace Sodium Sulfate with STPP. Just a thought.
  • try a hydrotrope like  SXS (sodium xylene sulfonate).
  • BILOBILO Member
    Hi Chemist77,

    Glycerin is used as an emollient. 
    I will try your suggestion of replacing Sodium Sulfate with STPP and i will give you a feedback on that.
    Thank you.
  • Chemist77Chemist77 Member, PCF student
    Dr. Bob do you think a hydrotrope would be suitable for a powder detergent? We generally advise SXS & SCS for liquid detergents where viscosity or solubility is an issue. Would appreciate your comments.
  • Chemist77 A powder detergent--no--just for liquids as you say for viscosity and/solubility.
  • Chemist77Chemist77 Member, PCF student
    Thank you Dr. Bob
  • anytime   your welcome
  • BILOBILO Member

    Above is a picture of the final product with Sodium Sulfate crystal pieces clearly showing up.
    By the way this is a paste product, not powder nor liquid.
  • BILOBILO Member
    Chemist77, replacing Sodium Sulfate with STPP will not be cost effective. The price of STPP is 4.5 times higher. 
  • Chemist77Chemist77 Member, PCF student
    Try changing order of addition and if it is a paste then as Dr. Bob suggested use a hydrotrope.
  • BILOBILO Member
    Thank you for the feedback. I need some clarifications:
    Chemist77, Dr.Bob.

    1. Do you mean by SCS Sodium Coconut Sulfate? 

    2. I found out that SLS Sodium Lauryl Sulfate is the equivalent to SCS. Can it be used as Hydrotrope?

    3. How about SLES (Sodium Laureth Sulfate) can it replace the Sodium Coconut Sulfate? It is readily available and cheap.

    Thank you in advance.
  • BILOBILO Member
    i found it....mix Sodium Sulfate with water first and then add it to the mix slowly.
    That is all it took.
    Thank you for your feedback.
  • Chemist77Chemist77 Member, PCF student
    And thank you BILO for sharing your outcome.
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