Zinc Chloride – CAS No. 7646-85-7
Product Overview
Zinc Chloride (ZnCl₂), a hygroscopic inorganic salt, is a versatile Lewis acid and fluxing agent essential in galvanizing, wood preservation, and chemical synthesis. This white, odorless crystalline powder or deliquescent solid offers high solubility in water (432 g/100 mL at 25°C) and a strongly acidic pH of 4.0-5.0 in 5% solution, enabling effective metal surface activation and dehydration in organic reactions. With a purity ≥98%, it promotes adhesion in hot-dip galvanizing, inhibits fungal growth in timber treatments, and catalyzes esterifications and isomerizations in pharmaceuticals. Its thermal stability up to 290°C decomposition supports high-temperature fluxes, while low heavy metal impurities ensure safety in water-soluble formulations, making it a reliable choice for industrial and laboratory applications.
Key benefits of Zinc Chloride include:
- Fluxing Efficiency: Cleans metal surfaces by removing oxides, improving weldability and coating uniformity.
- High Solubility: Rapid dissolution for precise dosing in aqueous systems and electrolytes.
- Catalytic Power: Accelerates reactions as a mild acid without harsh corrosiveness.
- Preservative Strength: Penetrates wood fibers to prevent rot and decay for extended service life.
- Regulatory Compliance: Compliant with REACH and TSCA for industrial uses, GRAS for select food processing aids.
Zinc Chloride is produced via the reaction of zinc oxide with hydrochloric acid, followed by crystallization, yielding a high-purity product meeting FCC and USP standards.
Technical Specifications
| Property | Value/Description |
|---|---|
| Chemical Formula | ZnCl₂ |
| CAS Number | 7646-85-7 |
| Molecular Weight | 136.30 g/mol |
| Appearance | White crystalline powder |
| Purity | ≥98% |
| pH (5% Solution) | 4.0-5.0 |
| Solubility in Water | 432 g/100 mL at 25°C |
| Density | 2.91 g/cm³ |
| Melting Point | 290°C (decomposes) |
| Boiling Point | 732°C |
| Bulk Density | 1.0-1.2 g/mL |
| Storage | Cool, dry place; airtight containers |
These specifications ensure Zinc Chloride’s performance in fluxing, catalytic, and preservative roles.
Applications
Metalworking and Galvanizing
- Flux for Hot-Dip Galvanizing: Applied at 10-20% in ammonium chloride baths to prepare steel for zinc coating, enhancing corrosion resistance.
- Soldering and Welding: 5-15% solutions as flux to remove oxides from copper and brass surfaces.
Wood Preservation and Construction
- Fire Retardant Treatments: Impregnated at 5-10% in lumber to char formation and reduce flammability in building materials.
- Fungal Inhibitor: 2-5% in timber preservatives to control rot and mold in outdoor structures.
Chemical Synthesis
- Catalyst in Esterification: 1-3% in reactions of alcohols and carboxylic acids for biodiesel and fragrances.
- Pharmaceutical Intermediates: Dehydrating agent in cyclization for antihistamines and antiseptics.
Why Choose Our Zinc Chloride?
Ours is refined from high-grade zinc with iron <10 ppm and sulfate <0.005%, delivering dust-free crystals and superior fluxing without residue buildup. Galvanizers achieve 25% faster line speeds and 20% better coating adhesion. Available in anhydrous powder and 60-75% solutions for technical/pharma/food grades, packaged in 25kg bags or 50kg drums, with Kosher, Halal, and ISO certifications for global reliability.
Frequently Asked Questions (FAQs)
What is Zinc Chloride?
It is a zinc salt with formula ZnCl₂ and CAS 7646-85-7, used as a flux and catalyst. It’s a white powder that activates metal surfaces and promotes reactions in synthesis and preservation.
How is Zinc Chloride used in galvanizing?
Dissolve 15-25% in water for pickling baths; it etches oxides from steel, preparing for zinc immersion and ensuring uniform, durable coatings.
Is Zinc Chloride safe for wood treatment?
Yes, at regulated concentrations (≤5%), it’s EPA-approved for pressure-treated lumber, providing rot resistance without leaching in outdoor exposure.
What is the shelf life of Zinc Chloride?
In sealed, dry storage below 30°C, anhydrous powder remains stable for 2-3 years, though hygroscopic—use desiccants to prevent clumping.
Can Zinc Chloride be used in pharmaceutical synthesis?
it catalyzes Friedel-Crafts and dehydration reactions at 1-5%, USP-grade ensuring low impurities for API production.
Does Zinc Chloride affect solution pH?
Its acidic pH (4-5) lowers system pH mildly, ideal for fluxes but requires neutralization in neutral formulations like preservatives.
What packaging options are available for Zinc Chloride?
We offer 25kg polyethylene-lined bags, 50kg plastic drums, and 1000kg supersacks, all moisture-proof for safe handling.
For flux recipes, purity verification, or custom solutions, our technical team provides expert support.
Contact Us
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