A sodium naphthalene formaldehyde (SNF) manufacturer makes sodium naphthalene sulfonate formaldehyde condensate from naphthalene, sulfuric acid, formaldehyde and caustic soda, then dries it to a brown powder. This page explains how SNF is produced, which quality checks a manufacturer should run on every batch, and what a buyer should check before approving a source.
How SNF Is Manufactured
- Sulfonation: molten naphthalene reacts with concentrated sulfuric acid at high temperature to form naphthalene sulfonic acid, mainly the beta isomer.
- Condensation: formaldehyde is added and the sulfonated rings are linked into chains. Time, temperature and acid level control the chain length, which drives dispersing performance.
- Neutralisation: sodium hydroxide converts the acid to the sodium salt. Excess sulfuric acid becomes sodium sulfate.
- Sulfate control and drying: part of the sodium sulfate may be removed, then the solution is spray-dried. The remaining sulfate sets the grade (5%, 10%, 18% or 20% max).
Batch Quality Checks
| Check | Why it matters | Our TDS limit |
|---|---|---|
| Cement paste fluidity | Direct measure of dispersing power | 220 mm min (SNF-5, SNF-10); 210 mm min (SNF-18, SNF-20) |
| Sodium sulfate | Defines the grade; affects active content and liquid stability | 5 / 10 / 18 / 20% max |
| Chloride | Limited in reinforced concrete | 0.4% max (SNF-5, SNF-10); 0.5% max (SNF-18, SNF-20) |
| Solids | Active product per kg | 91% min |
| pH | Batch consistency | 7 – 9 |
| Concrete test | Water reduction, air, strength ratio | Water reduction 14% min (SNF-5 TDS) |
What to Check Before Approving a Manufacturer
- TDS and SDS for the exact grade, with test methods; a recent batch COA that uses the same methods.
- Whether the plant runs its own sulfonation and condensation, or blends bought-in material. Ask to see the reaction and spray-drying lines.
- Laboratory equipment for the fluidity, sulfate and chloride tests, and retained samples per batch.
- Consistency: compare COAs from several batches and test a pre-shipment sample in your cement.
- Packaging (25 kg bags or 500–600 kg jumbo bags), labelling, and export documents.
A step-by-step audit and RFQ checklist is in how to choose an SNF supplier in China.
Our SNF Grades
| Grade | Sodium sulfate (Na2SO4) | Chloride (Cl–) | Cement paste fluidity | Solids | pH |
|---|---|---|---|---|---|
| SNF-5 (GAC-SNF-5) | 5% max | 0.4% max | 220 mm min | 91% min | 7 – 9 |
| SNF-10 (GAC-SNF-10) | 10% max | 0.4% max | 220 mm min | 91% min | 7 – 9 |
| SNF-18 (GAC-SNF-18) | 18% max | 0.5% max | 210 mm min | 91% min | 7 – 9 |
| SNF-20 (GAC-SNF-20) | 20% max | 0.5% max | 210 mm min | 91% min | 7 – 9 |
| Powder Grade, high solids (GAC-SNF-P) | 10% max | Below 200 ppm | Not listed | 95% min | 6.5 – 8.5 (1:10) |
Data sheets, samples and quotations: SNF product page.
Frequently Asked Questions
How is sodium naphthalene formaldehyde manufactured?
By sulfonating naphthalene with sulfuric acid, condensing the product with formaldehyde, neutralising with sodium hydroxide and spray-drying. The sodium sulfate left after neutralisation sets the grade.
What should I check when choosing an SNF manufacturer?
Grade-specific TDS and SDS, batch COAs with stated test methods, the plant’s own production and laboratory capability, batch-to-batch consistency, and a pre-shipment sample tested in your cement.
What quality tests are run on SNF?
Cement paste fluidity, sodium sulfate, chloride, solids and pH on each batch, with concrete tests (water reduction, air, strength ratio) for type testing.
