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D456-85 – Standard Test Method Technical Guide
This specification, designated D456-85 (Reapproved 1997), covers caustic soda (anhydrous) for industrial cleaning applications. It defines requirements for chemical purity, packaging, and testing to ensure safe and effective use in washing, cleaning, and scouring processes where a strongly alkaline material is needed.
🔬 Chemical Composition and Properties
Caustic soda (anhydrous) must be purchased by net weight and conform to the following chemical composition limits as received. These values guarantee the material’s effectiveness in alkaline detergent applications.
| 🟦 Component | 📏 Specification |
|---|---|
| Total alkalinity as Na₂O | Min 75.5% |
| Sodium hydroxide (NaOH) | Min 96% |
| Carbonate as Na₂CO₃ | Max 2% |
These limits ensure the material’s suitability for demanding cleaning operations where high alkalinity is required.
📦 Packaging and General Requirements
The material shall be supplied in air-tight containers in flake, coarsely powdered, or solid form as specified by the purchaser. Packaging and labeling must comply with all local, state, and federal regulations. The standard emphasizes safe handling due to the hazardous nature of caustic soda.
⚠️ Safety Alert: Caustic soda is hazardous if not managed properly. Obtain safety data from suppliers, and in case of exposure, apply first aid and seek medical attention immediately. Store in airtight containers to prevent moisture absorption and contamination.
⚙️ Sampling and Analysis
Sampling and chemical analysis shall be performed according to ASTM Test Methods D 501. This ensures that the material meets the specified composition requirements for total alkalinity, sodium hydroxide, and carbonate content.
✅ Quality Assurance: Regular sampling and analysis per D 501 confirm compliance with the standard, guaranteeing performance in alkaline detergent applications.
❓ Frequently Asked Questions
🔍 What is the minimum purity level for sodium hydroxide?
Caustic soda (anhydrous) must contain at least 96% sodium hydroxide by weight.
💡 How is the material packaged?
It must be in air-tight containers and can be flake, coarsely powdered, or solid form based on buyer requirements.
⚡ What are the maximum carbonate limits?
The carbonate content, expressed as Na₂CO₃, must not exceed 2% by weight.
📌 Which test methods govern analysis?
Analysis must follow ASTM D 501 for sampling and chemical testing.