Aluminum sodium sulfate

E number E521CAS 10102-71-3

Aluminium sodium sulfate is a firming agent and a raising-agent component in some baking powders.

Where it is and isn’t permitted

Status of Aluminum sodium sulfate by jurisdiction. Every jurisdiction this site covers is listed, including those where the substance does not appear.
JurisdictionStatusScope and limitsCitation
United StatesFood and Drug AdministrationPermitted21 CFR 182.1131retrieved 2026-09-07
Codex AlimentariusCodex Alimentarius Commission / JECFANot listedDoes not appear on this jurisdiction’s permitted list. That is not the same as being prohibited.

What it is made from

Crystallised from aluminium sulfate and sodium sulfate together.

  • Vegan
  • Vegetarian
CAS registry number
10102-71-3
InChIKey
GJPYYNMJTJNYTO-UHFFFAOYSA-J
PubChem
CID 24939

Every name it appears under

35 recorded names. A label may use any of them.

E number

  • E521

CAS registry number

  • 10102-71-3

As it appears in regulation

  • Aluminum sodium sulfate

Other names

  • ALUMINIUM SODIUM BIS(SULFATE)
  • Aluminium sodium bis(sulphate)
  • ALUMINIUM SODIUM SULFATE
  • ALUMINIUM SODIUM SULFATE ANHYDROUS
  • Aluminium sodium sulphate
  • aluminium(3+) ion sodium disulfate
  • Aluminum sodium disulfate
  • ALUMINUM SODIUM SULFATE
  • Aluminum sodium sulfate (AlNa(SO4)2)
  • ALUMINUM SODIUM SULFATE ANHYDROUS
  • Aluminum sodium sulfate, NaAl(SO4)2
  • Aluminum sodium sulfic acid
  • Aluminum sodium sulphate
  • ALUMINUM SODIUM SULPHATE ANHYDROUS
  • Aluminum sodium sulphic acid
  • E 521
  • EXSICCATED SODIUM SULFATE
  • HSDB 571
  • INS NO.521
  • INS-521
  • NATRII SULFAS EXSICCATUS
  • Soda alum
  • Sodium alum
  • SODIUM ALUM ANHYDROUS
  • Sodium aluminium sulfate
  • Sodium aluminum sulfate
  • Sodium aluminum sulfate (NaAl(SO4)2)
  • SODIUM ALUMINUM SULPHATE
  • SULFURIC ACID, ALUMINIUM SODIUM SALT (2:1:1)
  • Sulfuric acid, aluminum sodium salt (2:1:1)
  • XUANMINGFEN

Systematic names

  • aluminum sodium disulfate

Hazard reference values

No reference value for this substance in the sources we hold.

Evidence and how bodies read it

Studies, and the differing conclusions regulators drew from them, are curated by hand rather than machine-read, and none has been written for this substance yet.

Sources for this page

  • ecfr retrieved 2026-09-07

Full licence terms and publisher details on Sources. How this page is built and updated: Method.

Machine-readable:/api/v1/additives/aluminum-sodium-sulfate.json