Borax Decahydrate

Alternate Names: Sodium TetraBorate Decahydrate, Borax 10-hydrate, 10 Mol Borax, Neobor, Borax

Oxide	Analysis	Formula
B2O3	36.52%	2.00
Na2O	16.26%	1.00
H2O	47.21%	n/a
Oxide Weight		201.25
Formula Weight		381.23

Notes

Borax Decahydrate is the refined form of natural sodium borate. Composed of boric oxide (B₂O₃), sodium oxide, and water, it is a mild, alkaline salt, white and crystalline, with excellent buffering and fluxing properties. Borax Decahydrate is an important multifunctional source of B₂O₃ (e.g. frits), particularly for processes in which the simultaneous presence of sodium is beneficial.

Borax is available in large crystal, powder, and granular form, the latter being the most practical for ceramic use. Although the 10 molecules of water in the theoretical formula vary somewhat, they are the source of the designation "10 Mol Borax". The water content can vary with storage (it tends to lose water with time). Where precision is required, it is necessary to measure the water content just before use (the material begins to melt in its own water of crystallization at 60.8C).

Almost all American borax comes from deposits of the crystalline precipitate mineral tincal in the Mohave Desert of California (Asian borax is called Tincal).

It is soluble in water, acids, glycol and other solvents. This solubility onormally disqualifies it for use in clay bodies and glazes (since during drying it will come to the surface with the water and be concentrated there). That being said, some have observed that the granular material is not all that soluble and it is necessary to ball mill glazes containing it. Of course, the smaller particle size will increase surface area and accelerate solubility overtime.

Actually, the solubility can be used to advantage to make self-glazing products like Egyptian Paste and it can produce a hardened surface in non-fired products. In addition, the migration issue during drying can be tolerated in some circumstances, borax can be employed in a traditional ceramic slip or glaze blend as a low-cost super-flux to produce a glaze or slip for low temperatures.

Rio Tinto Borax has many technical, granular and powder grades of this material. "20 Mule Team" borax is this material. It is also produced at the Bandirma Borax Plant in Turkey.

Related Information

The amazing fluxing power of boron (in borax)

The two top clay bars contain 15% hydrous borax. At cone 06, a very low temperature, it has already melted and drained out of the bars, running down over the others as a glass.

Original Container Bag of Borax Decahydrate

Links

URLs	http://www.etimineusa.com/borax-decahydrate/ Borax Decahydrate Data Sheet Etibor Compared to Borax Pentahyrdate, which has a similar chemical structure, Borax Decahydrate has a lower Boron content per unit mass, a higher ratio of bound water and is more hygroscopic. It dissolves in water more easily than most other boron products.
URLs	http://www.borax.com/pdfs/dist/Profile_Borax_Decahydrate.pdf Data Sheet US Borax
Materials	Anhydrous Borax A white, odorless product crystalline granular by dehydrating Borax to remove the crystal bound water.
Materials	Borax Pentahydrate
Materials	Boric Acid
Materials	Boric Oxide
Materials	Disodium Octaborate Tetrahydrate
Hazards	Boron Compounds and Their Toxicity
Typecodes	Generic Material Generic materials are those with no brand name. Normally they are theoretical, the chemistry portrays what a specimen would be if it had no contamination. Generic materials are helpful in educational situations where students need to study material theory (later they graduate to dealing with real world materials). They are also helpful where the chemistry of an actual material is not known. Often the accuracy of calculations is sufficient using generic materials.
Typecodes	Flux Source Materials that source Na2O, K2O, Li2O, CaO, MgO and other fluxes but are not feldspars or frits. Remember that materials can be flux sources but also perform many other roles. For example, talc is a flux in high temperature glazes, but a matting agent in low temperatures ones. It can also be a flux, a filler and an expansion increaser in bodies.
Oxides	B2O3 - Boric Oxide
Oxides	P2O5 - Phosphorus Pentoxide
Minerals	Borate Minerals The major borate minerals are Colemanite and Ulexite. The geology required for borates is found in v

By Tony Hansen
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