Metal Surface Treatment
Removal of rust, scale and oxide layers from steel and iron components.
Rotterdam Chemicals Group supplies Industrial Grade Oxalic Acid Dihydrate, a widely used organic dicarboxylic acid applied in rust removal, metal surface treatment, wood bleaching and specialty cleaning formulations. Oxalic Acid is valued for its ability to dissolve iron oxides, brighten metallic surfaces and remove mineral staining in controlled industrial environments. We support bulk and packaged supply with structured logistics coordination from our Rotterdam hub.
Oxalic Acid Dihydrate (CAS No. 6153-56-6) is an organic dicarboxylic acid with the molecular formula C2H2O4·2H2O. The anhydrous form (CAS 144-62-7) has the molecular formula C2H2O4. It appears as a white crystalline solid and is soluble in water. Oxalic Acid functions as both a reducing agent and a chelating agent, particularly effective in dissolving iron oxides (rust). This makes it relevant in metal cleaning, oxide removal and marine maintenance applications where controlled surface treatment is required.
Metal Surface Treatment
Removal of rust, scale and oxide layers from steel and iron components.
Industrial Cleaning
Component in cleaning formulations targeting iron stains and mineral deposits.
Marine Maintenance
Controlled rust removal and brightening of metal fittings and deck hardware.
Wood Processing
Bleaching and stain removal in wood treatment industries.
Textile & Leather Processing
Used in certain dyeing and finishing processes.
Specialty Chemical Manufacturing
Intermediate in chemical synthesis and processing applications.
200L drums (palletized)
1000L IBC containers
Road tank transportation
Bulk ISO tanks
Custom packaging solutions available upon request
*All formats available directly from our Rotterdam warehouse with international supply support.
Industrial Grade – Designed for rust removal, metal brightening, industrial cleaning and controlled oxide treatment applications.
Property
Value
|
Chemical Name |
|
Oxalic Acid Dihydrate |
|
CAS Number (Dihydrate) |
|
6153-56-6 |
|
CAS Number (Anhydrous) |
|
144-62-7 |
|
EC Number |
|
205-634-3 |
|
HS Code |
|
29171100 |
|
Molecular Formula (Dihydrate) |
|
C2H2O4·2H2O |
|
Molecular Weight (Dihydrate) |
|
126.07 g/mol |
|
Physical Form |
|
White crystalline solid |
|
Typical Assay (Industrial Grade) |
|
≥ 99% (industry typical) |
|
Insoluble Matter |
|
≤ 0.01% (typical) |
|
Sulphate |
|
≤ 0.02% (typical) |
|
Iron Content |
|
≤ 50 ppm (industry typical range) |
|
Solubility in Water (20°C) |
|
Soluble |
|
pH (5% solution) |
|
Approx. 1.3 – 1.5 |
|
Melting Point (Anhydrous) |
|
Approx. 189–191°C (decomposes) |
|
UN Number |
|
UN 3261 |
|
ADR Classification |
|
Class 8 – Corrosive |
|
IMDG Classification |
|
Class 8 – Corrosive |
|
Packing Group |
|
III (solid form, industry typical classification) |
|
Storage Conditions |
|
Store in dry, well-ventilated area, protected from moisture |
|
Stability |
|
Stable under recommended storage conditions |
REACH Registered
Compliant with European transport and safety standards
SDS, TDS, and Certificate of Analysis available upon request
Rotterdam Chemicals Group supports bulk, drum and containerised shipments globally. Given its corrosive classification under ADR and IMDG, Oxalic Acid transport is coordinated in accordance with dangerous goods handling requirements. We support structured long-term industrial procurement programs as well as recurring marine sector supply.
What is Oxalic Acid Dihydrate primarily used for in industrial and marine environments?
Oxalic Acid Dihydrate is primarily used for rust removal, metal brightening and oxide cleaning in industrial maintenance programs. It is particularly effective at dissolving iron oxide deposits on steel, iron and certain alloys, making it widely used in fabrication workshops, surface preparation processes and corrosion spot treatment. In marine environments, it is commonly applied for controlled rust removal on deck hardware, fittings and metallic components exposed to saltwater conditions. It is also used in wood bleaching, stain removal and selected textile processing operations.
How does Oxalic Acid chemically remove rust and iron stains?
Oxalic Acid reacts with iron oxides to form soluble iron oxalate complexes. This reaction breaks down visible rust layers and allows the oxide material to be rinsed away from the treated surface. Unlike strong mineral acids, Oxalic Acid provides more targeted oxide removal, reducing the risk of excessive base-metal attack when used under controlled conditions.
Is Oxalic Acid classified as dangerous goods for transport and storage?
Yes. Oxalic Acid (solid form) is typically classified under UN 3261 as a corrosive substance (ADR Class 8, Packing Group III). Shipments must comply with dangerous goods packaging, labeling and documentation requirements under ADR and IMDG frameworks.
What safety considerations should industrial users be aware of when handling Oxalic Acid?
Oxalic Acid is corrosive and toxic if ingested or absorbed in significant quantities. Direct skin or eye contact should be avoided, and appropriate personal protective equipment should be used during handling. Adequate ventilation is recommended during industrial use. Detailed hazard identification and recommended protective measures are outlined in the Safety Data Sheet.
Connect with our sales team to discuss packaging options and international delivery arrangements. Every shipment is supported by complete safety and compliance documentation. Contact us today to review availability and lead times.
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