Aluminum sulfate is readily soluble in water but insoluble in ethanol. It does not dissolve in pure sulfuric acid and undergoes slow hydrolysis in aqueous solutions. When heated to 770°C, it decomposes into aluminum oxide, sulfur trioxide, sulfur dioxide, and water vapor.
Aluminium sulfate octadecahydrate Chemical Properties
| Melting point | 86 °C |
| Density | 1,69 g/cm3 |
| Bulk density | 820kg/m3 |
| Storage temp | Sealed in dry,Room Temperature |
| Solubility | 364g/l |
| Form | Powder/Solid |
| Color | White |
| Specific Gravity | 1.69 |
| PH Range | 3 - 4 |
| PH | 2.5-4.0 (20g/l, H2O, 20℃) |
| Water Solubility | Soluble |
| Sensitive | moisture sensitive |
| InChI | InChI=1S/2Al.3H2O4S.18H2O/c;;3*1-5(2,3)4;;;;;;;;;;;;;;;;;;/h;;3*(H2,1,2,3,4);18*1H2/q2*+3;;;;;;;;;;;;;;;;;;;;;/p-6 |
| InChIKey | AMVQGJHFDJVOOB-UHFFFAOYSA-H |
| SMILES | S([O-])([O-])(=O)=O.S([O-])([O-])(=O)=O.S([O-])([O-])(=O)=O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.[Al+3].[Al+3] |
| CAS DataBase Reference | 7784-31-8(CAS DataBase Reference) |
| EPA Substance Registry System | Sulfuric acid, aluminum salt (3:2), octadecahydrate (7784-31-8) |
Safety Information
| Hazard Codes | N-Xn,Xi,N,Xn |
| Risk Statements | 51/53-41-36/37/38-22 |
| Safety Statements | 61-37/39-29-26-39 |
| RIDADR | UN3260 - class 8 - PG 3 - RQ - Corrosive solid, acidic, inorganic, n.o.s., HI: all |
| WGK Germany | 1 |
| RTECS | WS5697000 |
| HS Code | 2833 22 00 |
| Toxicity | LD50 orally in Rabbit: > 5000 mg/kg |
Product Usage
Aluminum sulfate is widely used in the paper industry. In its acidic form, with a slight excess of H₂SO₄, it controls the pH of pulp slurries, treats process waters, sets dyes, and precipitates dissolved resin to fix sizing on fibers. In a slightly basic form, with a slight excess of Al₂O₃, it is applied in drinking and wastewater treatment, such as reducing phosphorus content. Other key applications include dyeing, tanning, acting as a catalyst, modifying concrete, and serving as a raw material in the production of various chemicals and pharmaceutical products.
