Aluminum Sulfate, sometimes referred to as alum or papermaker’s alum, is a nontoxic, water-soluble inorganic compound with the chemical formula Al₂(SO₄)₃ and CAS number 10043-01-3. It presents as a white, odorless crystalline solid with a sweet, mildly astringent taste. Aluminum Sulfate is primarily used as a coagulating and flocculating agent in the purification of drinking water and wastewater treatment, and also finds broad application in textile dyeing, paper manufacturing, agriculture, and a wide range of industrial and consumer product formulations.
Aluminum Sulfate is typically supplied as white crystals, granules, pieces, or powder and is available in bulk quantities and custom packaging options depending on application requirements.
Contact The Chemical Company for current packaging options, lead times and supply chain updates.
Aluminum Sulfate (Al₂(SO₄)₃) is a water-soluble, odorless, white crystalline compound. It is insoluble in ethanol and may burn but will not ignite. Aluminum sulfate is manufactured by reacting freshly precipitated aluminum hydroxide with an appropriate quantity of sulfuric acid. The resulting solution is then evaporated and allowed to crystallize, yielding the product in the form of white, lustrous crystals, pieces, granules, or powder.
As a coagulant in water and wastewater treatment, aluminum sulfate works by reacting with water to form aluminum hydroxide, a gelatinous precipitate that attracts and binds suspended particles, bacteria, and impurities, allowing them to settle out of solution. This process, known as flocculation, is one of the most widely used methods for clarifying drinking water and treating industrial effluents.
In the paper industry, aluminum sulfate is used as a sizing agent to improve water resistance and surface properties of paper. In the textile industry, it serves as a mordant to fix dyes to natural fibers and improve color fastness. In agriculture, it is used to lower the pH of alkaline soils, making nutrients more available to acid-loving plants such as blueberries, azaleas, and rhododendrons.
Aluminum sulfate is also used in the manufacture of adhesives and sealants, pigments and dyes, finishing agents, non-pesticidal agricultural chemicals, building and construction materials, cleaning products, fabric and leather treatments, and personal care products.
Aluminum Sulfate is used across several industries and applications, including:
| Property | Value |
|---|---|
| Chemical Name | Aluminum Sulfate |
| CAS Number | 10043-01-3 |
| Molecular Formula | Al₂(SO₄)₃ |
| Appearance | White crystalline solid; available as crystals, granules, pieces, or powder |
| Odor | Odorless |
| Taste | Sweet, mildly astringent |
| Solubility | Soluble in water; insoluble in ethanol |
| Melting Point | 770°C (decomposes) |
| Density | 2.67 g/cm³ |
| Flammability | May burn; will not ignite |
Aluminum Sulfate is available in a range of packaging formats to meet your operational needs including crystals, granules, pieces, and powder. Custom packaging and supply solutions are available based on your application and volume requirements.
Contact The Chemical Company for current packaging options, lead times, and supply chain updates.
Aluminum Sulfate is most commonly used as a coagulant and flocculant in drinking water purification and wastewater treatment. It is also widely used as a sizing agent in paper manufacturing, a mordant in textile dyeing, a soil pH adjuster in agriculture, and as an ingredient in adhesives, construction materials, pigments, and personal care products.
Aluminum Sulfate is sometimes referred to as alum or papermaker’s alum in certain industries, though this is technically an improper use of the term. True alum refers to potassium aluminum sulfate (KAl(SO₄)₂·12H₂O), while aluminum sulfate (Al₂(SO₄)₃) is a distinct compound. Both are used in water treatment and textile applications but have different chemical compositions.
The CAS number for Aluminum Sulfate is 10043-01-3.
When added to water, Aluminum Sulfate reacts to form aluminum hydroxide, a gelatinous precipitate that attracts and binds suspended particles, bacteria, and impurities. This process, known as flocculation, causes the bound particles to clump together and settle out of solution, clarifying the water. It is one of the most widely used and cost-effective methods for purifying drinking water and treating industrial wastewater.
Aluminum Sulfate is considered nontoxic and noncombustible under normal conditions. It may cause mild irritation to skin, eyes, and the respiratory tract with prolonged or concentrated exposure. Appropriate personal protective equipment should be worn when handling the material in industrial quantities.
Aluminum Sulfate is available in a range of formats including white crystals, granules, pieces, and powder. Contact The Chemical Company at (401) 360-2800 or fill out our contact form for current packaging options, lead times, and supply chain updates.
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