Sodium Metasilicate vs Sodium Silicate: Different Modulus
Sodium metasilicate and instant sodium silicate powder are the two solid silicates buyers most often confuse. Both are inorganic sodium silicate salts. They differ in modulus — the molar ratio of SiO₂ to Na₂O — and that number determines alkalinity and silica behaviour.
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Short answer
The decisive difference is modulus — the molar ratio of SiO₂ to Na₂O. Sodium metasilicate is fixed at 1:1 and supplied as a solid under CAS 6834-92-0. Instant sodium silicate powder is the higher-modulus solid under CAS 1344-09-8, supplied as LGS-20 (modulus ≈ 1.9–2.1) and LGS-30 (modulus ≈ 2.9–3.1). That difference determines alkalinity and silica behaviour, which is why the two are named separately on an RFQ. Zhongzhi Chemical supplies both solids factory-direct from Changyi and replies within 12 hours.
The Decisive Difference: Modulus
Sodium metasilicate (Na₂SiO₃, CAS 6834-92-0 anhydrous) carries an approximately 1:1 molar ratio of SiO₂ to Na₂O — a modulus near 1.0. Instant sodium silicate powder (Na₂O·nSiO₂, CAS 1344-09-8) is supplied as LGS-20 (modulus ≈ 1.9–2.1) and LGS-30 (modulus ≈ 2.9–3.1). The higher the modulus, the more silica and the less free alkali the product carries per tonne.
This is why the two products are not interchangeable. Metasilicate's low modulus makes it a strong alkaline builder: it delivers high, immediately available alkalinity, which is what detergent, degreasing and metal-cleaning formulations are buying. Instant powder at the LGS moduli delivers comparatively more silica and less alkalinity, which is what binding, film-forming and adhesion systems review.
Both are inorganic compounds — a question buyers ask often enough that it is worth stating plainly. Neither is an organic chemical, and neither carries phosphate, which is why metasilicate in particular appears in phosphate-free reformulation work.
Which One Your Application Needs
Specify sodium metasilicate when the formulation needs alkalinity: powder and tablet detergents, industrial and institutional cleaners, degreasers, bottle-washing compounds, textile scouring and metal-surface cleaning. In these systems the buying criteria are Na₂O and SiO₂ content, iron, and dissolution behaviour, and the product ships as a dry solid.
Specify instant sodium silicate powder when the formulation needs silica functionality rather than metasilicate alkalinity: foundry binders and refractories, construction and cement systems, paper and pulp processing, soil stabilisation, and adhesive or coating systems. Here the governing specification is the powder grade (LGS-20 or LGS-30).
Detergent buyers should name the process step in the RFQ. Powder lines take solid sodium metasilicate. Stating the step, not only the chemical name, is how the quotation matches the grade.
Both Grades Ship as Solids
Sodium metasilicate and instant sodium silicate powder both ship as solids. Metasilicate ships as granules or powder in 25 kg bags or FIBC jumbo bags. Instant powder packing is confirmed on the RFQ for the grade selected.
Metasilicate is hygroscopic and needs sealed packing and dry storage to prevent caking. State packing and destination on the RFQ so the quotation matches the way the plant receives the material.
Specification Comparison for the RFQ
Sodium metasilicate anhydrous, granular and powder, is specified at SiO₂ 45.0–48.0% and Na₂O 50.0–51.5%, under CAS 6834-92-0. Iron on those forms is typical ≤100 ppm. The pentahydrate grade (Na₂SiO₃·5H₂O, CAS 10213-79-3) is specified at Na₂O 28–30% and SiO₂ 28–30%, with dry matter 56–60%. Compare the published bands.
Instant sodium silicate powder is named by grade: LGS-20 (modulus ≈ 1.9–2.1) or LGS-30 (modulus ≈ 2.9–3.1). No TDS is published for instant powder. The RFQ names the grade and the application so quotations are comparable.
For either product, request TDS, SDS and stamped COA samples on Downloads before order confirmation. A shipment COA is issued per order. Confirm packing method, loading quantity, destination port and required export documents so the landed cost is fully visible at the quotation stage.
FAQ
Is sodium metasilicate the same as sodium silicate?
No. Sodium metasilicate (Na₂SiO₃, CAS 6834-92-0) has a modulus near 1.0 and is bought for alkalinity. Instant sodium silicate powder (Na₂O·nSiO₂, CAS 1344-09-8) is LGS-20 or LGS-30 and is reviewed for silica functionality. They are related salts, not substitutes.
Is sodium metasilicate organic or inorganic?
Inorganic. Both sodium metasilicate and sodium silicate are inorganic sodium silicate salts, and neither contains phosphate, which is why metasilicate is widely used in phosphate-free detergent reformulation.
Can instant sodium silicate powder replace sodium metasilicate in a detergent?
Only where the formulation is built for it. Powder detergent lines take the solid, high-alkalinity metasilicate grade. Name the process step in the RFQ so the correct solid grade is quoted.
What should the RFQ state to get a comparable quotation?
For metasilicate: grade (anhydrous, granular or pentahydrate), Na₂O, SiO₂, Fe, particle size, packing and destination. For instant sodium silicate powder: LGS-20 or LGS-30, packing and destination. Request TDS, SDS and stamped COA samples on Downloads, and a shipment COA per order.
Request a quotation
Send application, monthly quantity, packing and destination port. Grade is optional. Zhongzhi Chemical replies within 12 hours.
- Grade
- Monthly quantity (MT)
- Application
- Buyer type
- Packing
- Destination port
Next Step
Request a quotation
Use the guide to define grade, packing, volume and documents. Then continue to product specifications or send an RFQ for factory review.
RFQ Checklist
- Grade
- Monthly quantity (MT)
- Application
- Buyer type
- Packing
- Destination port