Description
Ammonium alum, NH4Al(SO4)2, supplied as the dodecahydrate. A leavening-acid and firming agent functionally analogous to potash alum, with the ammonium cation replacing potassium.
Colorless to white crystalline material with characteristic astringent taste. Soluble in water with acidic pH due to aluminum cation hydrolysis; the ammonium cation contributes weak additional acidity through partial dissociation.
We supply food-grade Ammonium Aluminum Sulfate from manufacturers in China holding ISO, Halal, Kosher and other certifications relevant to the product and production. Aluminum-additive use restrictions in several jurisdictions should be confirmed before purchase.
Common market grades include food-grade dodecahydrate for baking-powder and pickling applications, pharmaceutical USP grade, and industrial grade for water treatment and chemical synthesis.
Bulk and reduced-MOQ shipments. Batch-level COA covering assay, aluminum, ammonium, iron, heavy metals, and microbiology.
Introduction
Ammonium Aluminum Sulfate is the ammonium-cation analog of potash alum, with broadly similar chemistry and applications. The compound has been produced industrially since the nineteenth century and was widely used in baking-powder formulations in the United States through the twentieth century.
Production proceeds by reaction of aluminum sulfate with ammonium sulfate in solution, followed by crystallization of the dodecahydrate. The crystals share the characteristic octahedral habit of alum-family compounds. Industrial production is typically integrated with sulfuric acid and ammonia plants.
Regulated in the EU as E523, subject to the same aluminum-additive restrictions in several jurisdictions as SAS and potash alum. In the United States, the substance is permitted under 21 CFR 182.1127. Customers should confirm current destination-market regulations before specifying.
Mechanism is dual: aluminum hydrolysis provides the leavening-acid acidity that reacts with sodium bicarbonate, while the ammonium cation contributes additional weak acidity and decomposes on heating. The decomposition products from the ammonium fraction can leave a slight aftertaste in thick baked goods, which is why ammonium alum is less common in modern bread and cake formulations than its potassium counterpart or the SALP and SAPP alternatives.
Strategic positioning: Ammonium alum is a niche specialty ingredient used in traditional baking-powder recipes and in pickling applications where its specific acidity profile is preferred over potash alum. Regulatory pressure on aluminum-containing food additives has further narrowed its commercial role.
Where it is used
- Leavening acid in selected baking powder and self-rising flour formulations
- Pickling firming agent in cucumber, melon-rind, and traditional preserve recipes
- Clarification in selected sugar refining and beverage filtration operations
- Astringent in pharmaceutical and personal-care applications
- Mordant in dyeing and textile applications outside the food sector
- Water treatment flocculant in some industrial systems
- Component in fire-retardant chemistry
- Aluminum source in specialty chemical synthesis
Technical data
| Item | Specification |
|---|---|
| Appearance | Colorless to white crystalline material |
| Assay (NH4Al(SO4)2·12H2O) | 99.0% to 100.5% |
| Aluminum content | 5.7% to 6.0% |
| Ammonium (as NH4) | 3.8% to 4.2% |
| Iron (as Fe) | ≤ 50 mg/kg |
| Heavy metals (as Pb) | ≤ 10 mg/kg |
| Arsenic | ≤ 3 mg/kg |
| Fluoride | ≤ 30 mg/kg |
| Selenium | ≤ 30 mg/kg |
| Particle size | Per customer specification |
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