Aluminum Sulfate
Introduction of Aluminum sulfate
Aluminum sulfate is a salt with the formula Al2(SO4)3. It is soluble in water and is mainly used as a coagulating agent in the purification of drinking water and wastewater treatment plants, and also in paper manufacturing. Our Aluminium Sulphate has powder granules, flakes, and tablets, we also can supply no-ferric, low-ferric, and industrial grade.
Aluminum sulfate exists as white, lustrous crystals, granules, or powder. In nature, it exists as the mineral alunogenite. Aluminum sulfate is sometimes called alum or papermaker’s alum.
| Chemical formula | Al2(SO4)3 |
| Molar mass | 342.15 g/mol (anhydrous) 666.44 g/mol (octadecahydrate) |
| Appearance | White crystalline solid Hygroscopic |
| Density | 2.672 g/cm3 (anhydrous) 1.62 g/cm3(octadecahydrate) |
| Melting point | 770 °C (1,420 °F; 1,040 K) (decomposes, anhydrous) 86.5 °C (octadecahydrate) |
| Solubility in water | 31.2 g/100 mL (0 °C) 36.4 g/100 mL (20 °C) 89.0 g/100 mL (100 °C) |
| Solubility | slightly soluble in alcohol, dilute mineral acids |
| Acidity (pKa) | 3.3-3.6 |
| Magnetic susceptibility (χ) | -93.0·10−6 cm3/mol |
| Refractive index(nD) | 1.47[1] |
| Thermodynamic data | Phase behavior: solid–liquid–gas |
| Std enthalpy of formation | -3440 kJ/mol |
Packing: lined with plastic bag, outer woven bag. Net weight: 50 kg bag
Household Uses
Some of the most common uses of aluminum sulfate are found within the home. The compound is often found in baking soda, although there’s some controversy over whether it’s appropriate to add aluminum to the diet. Some antiperspirants contain aluminum sulfate because of its antibacterial properties, although as of 2005 the FDA does not recognize it as a wetness reducer. Finally, the compound is the astringent ingredient in styptic pencils, which are designed to stop small cuts from bleeding.
Gardening
Other interesting uses of aluminum sulfate around the house are in gardening. Because aluminum sulfate is extremely acidic, it’s sometimes added to very alkaline soils to balance the pH of plants. When aluminum sulfate comes into contact with water, it forms aluminum hydroxide and a diluted sulfuric acid solution, which alters the soil acidity. Gardeners who plant hydrangeas apply this property to change the flower color (blue or pink) of the hydrangeas since this plant is very sensitive to soil pH.
Aluminum SulfateWater Treatment
One of the most important uses of aluminum sulfate is in water treatment and purification. When added to water, it causes microscopic impurities to clump together into larger and larger particles. These clumps of impurities will then settle to the bottom of the container or at least get large enough to filter them out of the water. This makes the water safer to drink. On the same principle, aluminum sulfate is also sometimes used in swimming pools to decrease the cloudiness of the water.
Dyeing Fabrics
Another one of the many uses of aluminum sulfate is in dyeing and printing on cloth. When dissolved in a large amount of water that has a neutral or slightly alkaline pH, the compound produces a gooey substance, aluminum hydroxide. The gooey substance helps dyes stick to the cloth fibers by making the dye water insoluble. The role of aluminum sulfate, then, is as a dye “fixer,” which means that it combines with the molecular structure of the dye and the fabric so the dye doesn’t run out when the fabric gets wet.
Paper Making
In the past, aluminum sulfate was used in making paper, although synthetic agents have mostly replaced it. The aluminum sulfate helped to the size of the paper. In this process, aluminum sulfate was combined with rosin soap to change the absorbency of the paper. This changes the ink-absorbing properties of the paper. Using aluminum sulfate means that the paper was made under acidic conditions. The use of synthetic sizing agents means that acid-free paper can be produced. The acid-free paper does not break down as fast as paper sized with acid.
