Packaging and Storage

Recommendations for optimal shelf life

Designed for Optimal Results

The storage (shelf) life of U.S. Borax borates—the period during which they remain in usable condition—depends on many factors. Most borates are relatively stable, so when stored and handled according to recommended practices, our products have demonstrated the ability to remain free-flowing and suitable for a year or more after packing. Our packaging is designed to provide maximum protection and provides satisfactory results when reasonable care is taken during storage and handling.
For optimal results, keep containers in a dry warehouse, off the floor, away from external heat (ie, keep temperatures less than 85°F [29°C]), and out of humid atmospheres (ie, maintain a relative humidity of less than 45%). Preferably, store product on wooden pallets and keep the number of layers on a pallet to a minimum. Do not stack pallets on top of one another for extended periods.

Bagged borate product handling and storage

20 Mule Team® Borax products are typically supplied in 50 lb (25 kg) bags. We pack these products in multiwall kraft-paper bags incorporating a polyethylene barrier layer. For added protection, pallet shipments are stretch-wrapped. Borates are also available in Intermediate Bulk Carriers (IBCs): primarily in 2,500 lb sacs for the North American market or 1,100 kg super bags for international markets. Other sizes are available for specialty products. These super bags are constructed from white woven 100% polypropylene, with or without polyethylene liners (depending on customer preference).

Store borates in a dry warehouse, preferably on wooden pallets. Do not allow bags to rest directly on a concrete or earthen floor. To minimize product compaction, keep the number of layers on a pallet to a minimum and do not stack pallets on top of one another for extended periods.

Always store product using the First In/First Out (FIFO) principle: Use the oldest material first. If prolonged storage is necessary, you can reduce caking tendencies by rolling individual bags on a clean, dry surface. Lumps that are caused by compaction generally crumble easily; do not confuse lumps with the hard caking that results from changes in water content. Caked material is chemically unchanged and suitable for most industrial applications. In the case of borax decahydrate EP, NF, and SP grades, we recommend NOT storing the product in a controlled atmosphere below 60% of relative humidity. If necessary, changes in water content can be determined in a laboratory. 

For storage information for specific bagged products, download Borate handling and storage (PDF) in English or Español.

Borates Best Practices - Bags

Bulk borate product storage

When storing bulk borate products in silos, use either concrete or mild steel. (Do not use steel silos to store Optibor®, due to potential corrosion problems.) For silos with a capacity of fewer than 500 tons, steel construction might be the lower-cost option. Even with concrete silos, using steel for the conical structure might be more economical.

Although most borates can be stored in silos, some borates, such as Dehybor®, can cake if storage is prolonged (due to the product’s hygroscopic nature). Although Granubor® products are designed to resist physical degradation, there is increased potential to damage granules where the product drops into storage bins or silos.

For details about silos, including design, coating, dust control, particle segregation, and discharge, download the Borate handling and storage (PDF) in English or Español.

Borate Best Practices - Silos

Powdered products are much more susceptible to compaction than granular products. Similar to household powders (eg, icing sugar), powders often form loose agglomerates quickly when stored. However, these agglomerates disintegrate under hand pressure and this compaction should not be mistaken for hard caking. Our team can help identity whether this is a risk in your application.

Expected shelf life of borates

Borates are chemically stable indefinitely when stored in the original, intact packaging in a dry and covered warehouse. Therefore, the concept of an expiration date is not typically applicable.

All borates have a natural tendency to cake under prolonged storage. This tendency is intensified when the product is compacted or in extreme or cycling heat or humidity. Therefore, we recommend you store product on racking or in a single layer and apply the First In First Out (FIFO) principle of stock control.


Our National Formulary (NF) and European Pharmacopoeia (EP) products are the only products that have a three-year-from-production expiration date (technically a retest date). This date is noted on the product’s Certificate of Analysis (COA).

Contact our customer service team to request an updated COA. 

U.S. Borax, part of Rio Tinto, is a global leader in the supply and science of borates—naturally-occurring minerals containing boron and other elements. We are 1,000 people serving 500 customers with more than 1,700 delivery locations globally. We supply 30% of the world’s need for refined borates from our world-class mine in Boron, California, about 100 miles northeast of Los Angeles.  Learn more about Rio Tinto.

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