Iron-free Aluminum Sulfate Granules
Overview
Iron-free aluminum sulfate granules are a specialized form of aluminum sulfate with minimal iron impurities (<0.005%), making them ideal for applications requiring color-sensitive outcomes. The granular form offers superior handling properties compared to powdered variants, with reduced dusting and improved flow characteristics. This high-purity variant is particularly valued in industries where iron contamination could affect product quality, such as in high-grade paper production or clear water treatment processes. The manufacturing process typically involves careful raw material selection and controlled crystallization to achieve the desired low-iron specification.
Physical and Chemical Properties
The granules exhibit a white to slightly off-white appearance, with typical particle sizes ranging from 1-3 mm for optimal dissolution rates. The anhydrous form (Al2(SO4)3) has a molecular weight of 342.15 g/mol and decomposes rather than melts at approximately 770°C. A key advantage is its high solubility in water (31.2 g dissolves in 100 mL at 0°C), which increases with temperature. The solution is acidic (pH ~2.5 for 10% solution) due to hydrolysis. Unlike standard aluminum sulfate, the iron-free version shows superior clarity in solution, critical for applications where color contamination must be avoided.
Main Applications
In water treatment, these granules serve as an effective coagulant for municipal and industrial wastewater, particularly where low residual iron content is mandated. The granular form allows for controlled dosing in continuous treatment systems. The paper industry utilizes this compound for rosin sizing in premium-grade papers, where iron impurities could cause discoloration. Textile manufacturers employ it as a mordant in dyeing processes for color-fast fabrics. Additional uses include catalyst supports in chemical synthesis and as a raw material for manufacturing other aluminum compounds where iron interference must be minimized.
Safety and Storage
While not classified as highly hazardous, the material can cause skin and eye irritation upon contact. Appropriate PPE including gloves and safety goggles should be worn during handling. Dust inhalation should be avoided through proper ventilation or respiratory protection. Storage requires dry conditions in tightly sealed containers to prevent caking from moisture absorption. Bulk storage silos should be constructed from corrosion-resistant materials as the compound is mildly corrosive to carbon steel. Incompatibilities include strong bases and alkaline substances, which can cause violent reactions. Spills should be contained and cleaned with water, avoiding dry sweeping to prevent dust dispersion.
B2B Procurement Guide
Industrial buyers should specify iron content requirements (typically <0.005% for sensitive applications) and verify certificates of analysis. Granule size distribution affects dissolution rates - standard ranges are 1-3 mm, but specialized sizes may be available. Bulk shipments (typically 25kg bags or 1-ton super sacks) should include moisture-proof packaging. For large-volume procurement, consider suppliers with ISO-certified manufacturing facilities and ask about batch consistency guarantees. Pricing is typically quoted per metric ton, with discounts available for contract quantities. Lead times may vary seasonally due to raw material availability in the aluminum supply chain.