Aluminum sulfate
10043-01-3 · 10124-29-5 · Alum · ALUM CAKE · Aluminii sulfas · Aluminii sulfas, hydrate · aluminium potassium sulfate 12-hydrate · aluminium potassium sulfate hydrate (1:1:2:12) · Aluminium sulfate · Aluminium sulfate (2:3) hydrate · aluminium sulfate anhydrous · Aluminium sulfate, hydrate · Aluminium sulphate · Aluminium Sulphuricum · Aluminum alum · Aluminum alum (VAN) · Aluminum sesquisulfate · ALUMINUM SULFATE · Aluminum sulfate (2:3) · Aluminum Sulfate (2:3) Hydrate · Aluminum sulfate (3:2) · Aluminum sulfate (Al2(SO4)3) · Aluminum sulfate anhydrous · Aluminum Sulphate · Aluminum sulphate (2:3) hydrate · Aluminum sulphate anhydrous · Aluminum sulphate hydrate · Aluminum trisulfate · Aluminum(III) silfate · aluminum(III) sulfate · Cake alum (VAN) · dialuminium trisulfate · DIALUMINIUM(3+) ION TRISULFATE · Dialuminum sulfate · Dialuminum sulphate · Dialuminum trisulfate · Dialuminum Trisulfate Hydrate · E 520 · FERTOSAN · Filter Alum · Gingi-Aid MAX Z-Twist 00 · Gingi-Aid MAX Z-Twist 1 · Gingi-Aid MAX Z-Twist 2 · Gingi-Aid MAX Z-Twist 3 · Hi Soft C 2 · HIS Styptic Pencil · INS NO.520 · INS-520 · Nalco 7530 · NICK RELIEF · Papermaker's Alum · Pearl Alum · Pickle Alum · Shaving Factory · Shaving Factory Disposable Styptic Pencil · Sulfatodialuminum disulfate (Al2(SO4)3) · SULFURIC ACID, ALUMINIUM SALT · Sulfuric acid, aluminum salt · Sulfuric acid, aluminum salt (3:2) · Sulfuric acid, aluminum(3+) salt (3:2) · Tai-Ace S 150 · Trim Men Styptic Pencil · E520 · Dialuminum trisulfate · Aluminium sulphate · Aluminum sulfate · Aliuminio sulfatas · Alumiinisulfaatti · Alumiiniumsulfaat · Aluminijev sulfat · Aluminium sulphate · Aluminiumsulfaat · Aluminiumsulfat · Alumínium-szulfát · Alumīnija sulfāts · Siarczan glinu · Solfato d'alluminio · SOLFATO DI ALLUMINIO · Sulfat de aluminiu · Sulfat tal-aluminju · Sulfate d’aluminium · Sulfato de aluminio · Síran hlinitý · Θειϊκό αργίλιο · Алуминиев сулфатE number E520CAS 10043-01-3
Listed as a firming agent by Canada and the US.
Listed as firming agents (CA, US) · colours (US) · emulsifiers (US) · acidity regulators (US) · sequestrants (US) · starch-modifying agents (CA) · processing aids (US)
- Canada: Firming agent — Health Canada, List of Permitted Firming Agents (List 6)
- United States: Firming agent — FDA, Substances Added to Food: ALUMINUM SULFATE
- United States: Color or coloring adjunct — FDA, Substances Added to Food: ALUMINUM SULFATE
- United States: Emulsifier or emulsifier salt — FDA, Substances Added to Food: ALUMINUM SULFATE
- United States: pH control agent — FDA, Substances Added to Food: ALUMINUM SULFATE
- United States: Sequestrant — FDA, Substances Added to Food: ALUMINUM SULFATE
- Canada: Starch-modifying agent — Health Canada, List of Permitted Starch-Modifying Agents (List 13)
- United States: Processing aid — FDA, Substances Added to Food: ALUMINUM SULFATE
Aluminium sulfate is a firming agent used in pickles and some canned vegetables, and a clarifying agent. It is one of the additives contributing dietary aluminium.
Where it is and isn’t permitted
| Jurisdiction | Status | Scope and limits | Citation |
|---|---|---|---|
| Australia and New Zealand | No listed food uses foundThis site has not matched this substance to any food use on this jurisdiction’s list of authorised food additives. A food additive may be used only in foods that list names. Flavourings, enzymes, processing aids and added nutrients are regulated separately and do not appear on it. | ||
| Canada | Permitted, with conditions | highest permitted level 900 mg/kg 7 permitted uses Show every permitted use
| Health Canadaand 6 further provisionsretrieved 2026-10-17 |
| European Union | Permitted, with conditions | 2 food categories highest permitted level 25 mg/l Show every food category
| Regulation (EC) No 1333/2008, Annex IIand 1 further provisionretrieved 2026-10-18 |
| Great Britain | Permitted, with conditions | 2 food categories highest permitted level 200 mg/kg or mg/l Show every food category
| Assimilated Regulation (EC) No 1333/2008and 1 further provisionretrieved 2026-10-18 |
| Japan | No listing matchedThis site imports only Japan’s list of designated additives (Appended Table 1 to the Regulations for Enforcement of the Food Sanitation Act), matched by English name. Existing additives, natural flavouring agents and ordinary foods used as additives are permitted outside that list and are not imported, so an empty row does not show that Japan does not permit the substance. | ||
| South Korea | No listing matchedThis site imports Part III of South Korea’s Standards and Specifications for Food Additives, matched by CAS number, then INS number, then exact name. Mixed preparations and sanitisers are not imported, and an entry whose identifiers disagreed with a page’s is held for review, so an empty row does not show that South Korea does not permit the substance. | ||
| United States | Permitted | 21 CFR 182.1125retrieved 2026-10-17 | |
| Codex Alimentarius | Not listedDoes not appear on this jurisdiction’s permitted list. That is not the same as being prohibited. |
How much is permitted
A listing usually limits the quantity as well as the food. Only one of the forms that takes is a figure: quantum satis and good manufacturing practice permit the amount the technological effect requires and no more, which is a limit rather than the absence of one. Figures below are the range across every food category this page is listed in, and categories differ between regulators — see how much is permitted.
| Canada | 50 mg/kg – 900 mg/kg | 2 numeric limit, 1 GMP, 4 no quantity stated |
|---|---|---|
| European Union | 25 mg/kg | 1 numeric limit, 1 no quantity stated |
| Great Britain | 25 mg/kg – 200 mg/kg | 2 numeric limit |
| United States | — | 1 no quantity stated |
What it is made from
Produced by dissolving bauxite or aluminium hydroxide in sulfuric acid.
- Vegan
- Vegetarian
Compare other additives on the dietary indexes.
- CAS registry number
- 10043-01-3
- InChIKey
- DIZPMCHEQGEION-UHFFFAOYSA-H
- PubChem
- CID 24850
The two specifications, compared
The European Union sets identity and purity by regulation; JECFA publishes its own through FAO, advisory until a country adopts it. Both documents are below in full. These are the parameters each puts a number on.
| Parameter | European Union | JECFA |
|---|---|---|
| Assay | no less than 99.5 % | no less than 99.5 % |
| Lead | no more than 5 mg/kg | no more than 5 mg/kg |
| Arsenic | no more than 3 mg/kg | — |
| Mercury | no more than 1 mg/kg | — |
The two documents state the same figures for every parameter compared here.
How the EU defines it
The legal specification an additive must meet to be sold as this E number in the EU — what it is, how it may be made, and the purity it must reach. From Commission Regulation (EU) No 231/2012.
E 520 Aluminium sulphate
Synonyms: Alum
Assay, identification and purity criteria
Description and assay
- Chemical name
- Aluminium sulphate
- Chemical formula
- Al₂(SO₄)₃
- Molecular weight
- 342,13
- Assay
- Content not less than 99,5 % on the ignited basis
- Description
- White powder, shining plates or crystalline fragments
Identification
- Test for aluminium
- Passes test
- Test for sulphate
- Passes test
- pH
- 2,9 or above (5 % solution)
- Solubility
- Freely soluble in water, insoluble in ethanol
Purity criteria
- Loss on ignition
- Not more than 5 % (500 °C, 3 hours)
- Alkalies and alkaline earths
- Not more than 0,4 %
- Selenium
- Not more than 30 mg/kg
- Fluoride
- Not more than 30 mg/kg
- Arsenic
- Not more than 3 mg/kg
- Lead
- Not more than 5 mg/kg
- Mercury
- Not more than 1 mg/kg
How JECFA defines it
The international specification for identity and purity, prepared by the Joint FAO/WHO Expert Committee on Food Additives and published by FAO. It is a different document from any above, written by a different body and revised on its own cycle; it is advisory, and a country adopts it or does not.
INS 520 Aluminium Sulfate, anhydrous
Synonyms: INS No. 520
Assay, identification and purity criteria
Description and assay
- Specification history
- Prepared at the 55 th JECFA (2000) and published in the Combined Compendium of Food Additive Specifications, FAO JECFA Monographs 1 (2005). A PTWI of 2 mg/kg bw for aluminium was established at the 74 th JECFA (2011).
- Chemical names
- Aluminium sulfate
- C.A.S. number
- 10043-01-3
- Chemical formula
- Al2(SO4)3
- Formula weight
- 342.13
- Assay
- Not less than 99.5% on the ignited basis
- DESCRIPTION
- White powder, shining plates, or crystalline fragments; odourless
- FUNCTIONAL USES
- Firming agent
- METHOD OF ASSAY
- Weigh accurately about 4 g of the sample, transfer into a 250-ml volumetric flask. Dissolve in water, dilute to volume with water, and mix. Pipet 10 ml of this solution into a 250-ml beaker, add 25.0 ml of 0.05 M disodium ethylenediaminetetra-acetate, and boil gently for 5 min. Cool, and with continuous stirring add in the order given: 20 ml of pH 4.5 buffer solution (77.1 g of ammonium acetate and 57 ml of glacial acid in 1000 ml), 50 ml of ethanol, and 2 ml of dithizone TS. Titrate with 0.05 M zinc sulfate until the colour changes from green-violet to rose-pink, and perform a blank determination, substituting 10 ml of water for the sample. Each ml of 0.05 M disodium ethylenediaminetetraacetate is equivalent to 8.553 mg of Al2(SO4)3.
Identification
- Solubility (Vol. 4)
- Freely soluble in water, insoluble in ethanol
- pH (Vol. 4)
- 2.9 or above (5% solution)
- Test for aluminium (Vol. 4)
- Passes test
- Test for sulfate (Vol. 4)
- Passes test
Purity criteria
- Loss on ignition (Vol. 4)
- Not more than 5% (about 500°, 3 h)
- Alkalis and alkaline earths (Vol. 4)
- To a boiling solution of 2 g of the sample in 150 ml of water add a few drops of methyl red TS. Then add ammonia TS until the colour of the solution just changes to a distinct yellow. Add hot water to restore the original volume, and filter while hot. Evaporate 75 ml of the filtrate to dryness, and ignite to constant weight. Not more than 4 mg of residue remains (about 0.4%).
- Fluoride
- Not more than 30 mg/kg See description under TESTS
- Lead (Vol. 4)
- Not more than 5 mg/kg Determine using an AAS/ICP-AES technique appropriate to the specified level. The selection of sample size and method of sample preparation may be based on the principles of the methods described in Volume 4 (under “General Methods, Metallic Impurities”).
- Selenium (Vol. 4)
- Not more than 30 mg/kg Test 0.2 g of the sample as directed in the Limit Test (Method II)
- Fluoride
- Lime Suspension Carefully slake about 56 g of low-fluoride calcium oxide (about 2 mg/kg F) with 250 ml of water, and add 250 ml of 60% perchloric acid slowly and with stirring. Add a few glass beads, and boil to copious fumes of perchloric acid, then cool, add 200 ml of water, and boil again. Repeat the dilution and boiling once more, cool, dilute considerably, and filter through a fritted glass filter, if precipitated silicon dioxide appears. Pour the clear solution, with stirring, into 1000 ml of a 1 in 10 sodium hydroxide solution, allow the precipitate to settle, and siphon off the supernatant liquid. Remove the sodium salts from the precipitate by washing 5 times in large centrifuge bottles, shaking the mass thoroughly each time. Finally, shake the precipitate into a suspension and dilute to 2000 ml. Store in paraffin-lined bottles and shake well before use. 100 ml of this suspension should give no appreciable fluoride blank when evaporated in a platinum dish and treated as directed below under "Procedure", beginning with "Ignite briefly at 600°,...". Distillation Apparatus Connect a 125-ml distillation flask with a condenser. Equip also with a thermometer and a capillary tube, both of which must extend into the liquid. Connect a small dropping funnel or a steam generator to the capillary tube. Support the flask on an asbestos mat with a hole which exposes about one-third of the flask to the flame. To minimize the distillation blank resulting from fluoride leached from the glassware, the distillation apparatus should be treated as follows: treat the glassware with hot 10% sodium hydroxide solution, followed by flushing with tap water and rinsing with distilled water. At least once daily, treat in addition by boiling down 15-20 ml of a 1 in 2 sulfuric acid solution until the still is filled with fumes; cool, pour off the acid, treat again with 10% sodium hydroxide solution, and rinse thoroughly. Procedure Add to the distilling flask 1.67 g of the sample, accurately weighed, and 25 ml of a 1 in 2 sulfuric acid solution. Distil until the temperature reaches 160°, then maintain at 160° to 165° by adding water from the funnel, collecting 300 ml of distillate. Oxidize the distillate by the cautious addition of 2 or 3 ml of fluoride-free 30% hydrogen peroxide (to remove sulfites), allow to stand for a few min, and evaporate in a platinum dish with an excess of Lime Suspension. Ignite briefly at 600°, then cool and wet the ash with about 10 ml of water. Cover the dish with a watch glass, and cautiously introduce under cover just sufficient 60% perchloric acid to dissolve the ash. Add the contents of the dish through the dropping funnel of a freshly treated distilling apparatus (the distilling flask should contain a few glass beads), using a total of 20 ml of 60% perchloric acid for dissolving the ash and transferring the solution. Add 10 ml of water and a few drops of a 1 in 2 silver perchlorate solution through the dropping funnel. Continue as directed in the Limit Test, Method I, Thorium Nitrate Colorimetric Method , beginning with "Distil until the temperature reaches 135° ...".
Every name it appears under
85 recorded names. A label may use any of them.
E number
- E520
CAS registry number
- 10043-01-3
- 10124-29-5
As it appears in regulation
- Aluminium sulphate
- Aluminum sulfate
Other names
- Alum
- ALUM CAKE
- Aluminii sulfas
- Aluminii sulfas, hydrate
- aluminium potassium sulfate 12-hydrate
- aluminium potassium sulfate hydrate (1:1:2:12)
- Aluminium sulfate
- Aluminium sulfate (2:3) hydrate
- aluminium sulfate anhydrous
- Aluminium sulfate, hydrate
- Aluminium sulphate
- Aluminium Sulphuricum
- Aluminum alum
- Aluminum alum (VAN)
- Aluminum sesquisulfate
- ALUMINUM SULFATE
- Aluminum sulfate (2:3)
- Aluminum Sulfate (2:3) Hydrate
- Aluminum sulfate (3:2)
- Aluminum sulfate (Al2(SO4)3)
- Aluminum sulfate anhydrous
- Aluminum Sulphate
- Aluminum sulphate (2:3) hydrate
- Aluminum sulphate anhydrous
- Aluminum sulphate hydrate
- Aluminum trisulfate
- Aluminum(III) silfate
- aluminum(III) sulfate
- Cake alum (VAN)
- dialuminium trisulfate
- DIALUMINIUM(3+) ION TRISULFATE
- Dialuminum sulfate
- Dialuminum sulphate
- Dialuminum trisulfate
- Dialuminum Trisulfate Hydrate
- E 520
- FERTOSAN
- Filter Alum
- Gingi-Aid MAX Z-Twist 00
- Gingi-Aid MAX Z-Twist 1
- Gingi-Aid MAX Z-Twist 2
- Gingi-Aid MAX Z-Twist 3
- Hi Soft C 2
- HIS Styptic Pencil
- INS NO.520
- INS-520
- Nalco 7530
- NICK RELIEF
- Papermaker's Alum
- Pearl Alum
- Pickle Alum
- Shaving Factory
- Shaving Factory Disposable Styptic Pencil
- Sulfatodialuminum disulfate (Al2(SO4)3)
- SULFURIC ACID, ALUMINIUM SALT
- Sulfuric acid, aluminum salt
- Sulfuric acid, aluminum salt (3:2)
- Sulfuric acid, aluminum(3+) salt (3:2)
- Tai-Ace S 150
- Trim Men Styptic Pencil
Systematic names
- Dialuminum trisulfate
Hazard reference values
| Type | Value | Population | Assessed by | Opinion |
|---|---|---|---|---|
| ADI | not allocated | — | JECFA | 1978 |
Evidence and how bodies read it
What assessing bodies concluded
Each conclusion is paraphrased in the body's own framing, from the published opinion linked beneath it. Where bodies differ, both stand; this site does not adjudicate between them or add a view of its own.
EFSA 2018
The ANS Panel concluded that aluminium sulphates (E 520–E 523) and acidic sodium aluminium phosphate (E 541), which are permitted in only a few specific products with exposure probably near zero, are of no safety concern at current authorised uses and use levels.
Common questions
Assembled from what is above, in the words the questions are usually asked in. Each answer is the same statement the relevant section makes, with the same citations behind it.
- What is E 520?
- E 520 is Aluminum sulfate. Aluminium sulfate is a firming agent used in pickles and some canned vegetables, and a clarifying agent. It is one of the additives contributing dietary aluminium.
- What is Aluminum sulfate used for in food?
- It is listed as a firming agent — the role Canada and the US assign it. This page shows every function each regulator records, with the citation for each.
- Where is Aluminum sulfate permitted?
- Of the seven regulators this site reads, Canada, the EU, Great Britain and the US permit it. Each permission is for named foods at named levels, not a blanket one; the table on this page gives them with citations.
- Is Aluminum sulfate vegan?
- Yes. Aluminum sulfate is not derived from animals, and is suitable for vegetarians. This page says what it is made from and how.
Sources for this page
- ca retrieved 2026-10-17
- eu retrieved 2026-10-18
- gb retrieved 2026-10-18
- ecfr retrieved 2026-10-17
- euspecs retrieved 2026-10-18
- jecfaspecs retrieved 2026-09-23
Full licence terms and publisher details on Sources. How this page is built and updated: Method.
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