Meta description: Learn the differences between borax pentahydrate and anhydrous borax. Compare their properties, use cases, storage rules and procurement tips for industrial buyers.
Borax pentahydrate and anhydrous borax are two widely used borate chemicals in global manufacturing. Many industrial buyers assume they can be swapped freely, but their crystal water content creates major differences in performance, storage and formulation.
Borax Pentahydrate
Chemical formula: \(\boldsymbol{Na_2B_4O_7·5H_2O}\). Turkish ETIBOR-48 is the most popular grade. It is white free-flowing crystalline granules with \(\boldsymbol{B_2O_3}\) at 48.6–49.3%. It decomposes around 122°C and releases water vapor. It has low hygroscopicity and resists caking under normal warehouse conditions.
Main applications: fiberglass, flat glass, ceramic glazes, enamel, agricultural boron fertilizer and detergent additives. It is the top bulk export borate, offering stable quality and competitive cost.
Anhydrous Borax
Chemical formula: \(\boldsymbol{Na_2B_4O_7}\). It is fully dehydrated borax, appearing as white glassy powder or granules. Its \(\boldsymbol{B_2O_3}\) reaches 68.5–69.4%, with moisture below 0.5%. It melts at 743°C without releasing steam.
The biggest downside is strong hygroscopicity. It absorbs moisture quickly from the air if packaging is broken, turning back into hydrated borax.
Main applications: metallurgy flux, metal brazing, optical glass and high-temperature special ceramics. It is selected for processes where steam bubbles will cause defects in molten products.
Core Comparison & Selection Guide
- Pick Borax Pentahydrate: Large-volume orders, fiberglass, standard ceramics, farm boron fertilizer, normal warehouse environment, cost control.
- Pick Anhydrous Borax: High-temperature melting scenarios, no steam allowed in production, premium glass and metallurgy.
Storage & Sourcing Pitfalls
Borax pentahydrate only needs dry storage and sealed bags. Anhydrous borax requires tight waterproof packaging. Once opened, consume it quickly; humid areas are not suitable for long-term storage.
Do not substitute them directly. Switching materials without recalculating formula ratios will cause product defects. Turkey mainly exports borax pentahydrate. Anhydrous borax is a secondary processed product with higher MOQ and longer lead time. Always calculate the effective \(\boldsymbol{B_2O_3}\) cost instead of simply comparing per-ton prices.
FAQ
Q1: Can I replace borax pentahydrate with anhydrous borax directly?
A: No. You must recalculate the formula based on different B₂O₃ content. Improper replacement causes bubbling or boron overdose.
Q2: Why is anhydrous borax more expensive?
A: It needs extra high-temperature dehydration processing. Its high boron concentration also brings stricter packaging and shipping requirements.
Q3: Is Turkish borax pentahydrate stable during ocean shipping?
A: Yes. With intact PP bags and pallet packing, it stays stable in normal sea freight without easy caking.