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Borate fluxes and chemicals

Your first choice to fuse samples for XRF, ICP and AA analysis

As the one-stop shop in fusion and the world leader in the production of borate fluxes, Claisse develops high-quality chemicals that are easy to use and that ensure no contamination.

Offered in two grades of purity (pure 99.98+% and ultra pure 99.995+%) and available with or without non-wetting agents, our lithium borate fluxes are homogeneous and available in bead format.

Use Claisse lithium borate fluxes to:

  • Avoid crystallization
  • Reduce the incidence of glass sticking to the platinumware
  • Avoid cracking

Make your life easier, try our pre-weighed or customized borate fluxes

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Why invest in the fluxes developed by Claisse?

Claisse fluxes are manufactured through a unique process that guarantees unmatched purity and outstanding physical properties. Here's why our fluxes are the best on the market:

  • Consistent quality: No need to stock large quantities of flux or to recalibrate your spectrometer after each order. With Claisse, you can always expect the same high-quality flux.
  • Fused and homogeneous: Claisse borate fluxes consist of homogeneous, spherical and vitreous particles. Each particle has the same composition to avoid segregation and to ensure the analytical accuracy of your analysis. There is no need to recalibrate the instrument every time a new batch of flux is used.
  • 99.98+% pure and 99.995+% ultra pure: Our fluxes are the purest on the market! We guarantee that our pure borate fluxes contain less than 10 ppm for each of the 15 selected elements. The level of contamination for ultra pure fluxes is carefully controlled and analyzed for 30 selected elements. A detailed certificate of analysis is supplied with each order.
  • High density: Claisse borate fluxes are three times denser than the other fluxes on the market. They never fill more than half of the crucible, even when fusions for large 40 mm disks are performed. It eliminates all risks of overflow during agitation.
  • Anhydrous: Claisse fluxes have the lowest water content on the market (< 0.05%).
  • Non-hygroscopic: Our fluxes consist of spherical glassy beads, they are therefore non-hygroscopic. A major problem with absorbed humidity is the loss of accuracy in the analytical results. It is caused by the induced error on the mass of flux weighed, and it affects the sample/flux ratio.
  • Controlled granulometry: Claisse fluxes are 100% less than 500 µm and contain no dust. Consequently, they do not tend to stick to the weighing pan, the funnel and the crucible wall. A controlled granulometry eliminates the segregation effect. It avoids the loss of flux and the formation of glass droplets on the wall of the crucible. It also allows better accuracy.
  • Non-wetting agents (NWAs) integrated: Our fluxes are available with integrated lithium bromide (LiBr) or lithium iodide (LiI). We know that adding an inconstant amount of NWAs to the melt can affect the accuracy of an analysis. You can solve this issue by using our fluxes with integrated NWAs. These fluxes are easier to use and they save you time because you do not have to add the NWAs separately during the fusion process.
  • Outstanding fluidity: Our borate fluxes are therefore easier to handle and weigh.
  • Available from stock: If you are out of stock or have an urgent request, we will promptly ship the product.


Do not hesitate to contact us to receive the proper MSDS needed.

Flux Catalog


Catalog NumberFluxMSDS 
C-0600-00LiT, Pure, 1 kgMSDS
C-0600-10LiT, Powder Flux, Pure, 500 gMSDS
C-0600-60LiT/LiBr 99.50/0.50, Pure, 1 kgMSDS
C-0600-63LiT/LiBr 99.00/1.00, Pure, 1KgMSDS
C-0600-70LiT/LiI 99.50/0.50, Pure, 1 kgMSDS
C-0601-00LiT, Ultra Pure, 1 kgMSDS
C-0601-60LiT/LiBr 99.50/0.50, Ultra Pure, 1 kgMSDS
C-0601-70LiT/LiI 99.50/0.50, Ultra Pure, 1 kgMSDS
C-0610-00LiM, Pure, 1 kgMSDS
C-0610-10LiM, Powder Flux, Pure, 500 gMSDS
C-0610-66LiM/LiBr 98.50/1.50, Pure, 1 kgMSDS
C-0611-00LiM, Ultra Pure, 1 kgMSDS
C-0611-66LiM/LiBr 98.50/1.50, Ultra Pure, 1 kgMSDS
C-0620-00LiT/LiM 50/50, Pure, 1 kgMSDS
C-0620-60LiT/LiM/LiBr 49.75/49.75/0.50, Pure, 1 kgMSDS
C-0620-63LiT/LiM/LiBr 49.50/49.50/1.00, Pure, 1 kgMSDS
C-0620-70LiT/LiM/LiI 49.75/49.75/0.50, Pure, 1 kgMSDS
C-0621-00LiT/LiM 50/50, Ultra Pure, 1 kgMSDS
C-0621-60LiT/LiM/LiBr 49.75/49.75/0.50, Ultra Pure, 1 kgMSDS
C-0621-63LiT/LiM/LiBr 49.50/49.50/1.00, Ultra Pure, 1 kgMSDS
C-0621-70LiT/LiM/LiI 49.75/49.75/0.50, Ultra Pure, 1 kgMSDS
C-0630-00Sodium Tetraborate, Pure, 1 kgMSDS
C-0631-00Sodium tetraborate, ultra pure, 1 kgMSDS
C-0640-00LiT/LiM 67/33, Pure, 1 kgMSDS
C-0640-10LiT/LiM, 67/33, powder flux, pure, 500 gMSDS
C-0640-60LiT/LiM/LiBr 66.67/32.83/0.50, Pure, 1 kgMSDS
C-0640-70LiT/LiM/LiI 66.67/32.83/0.50, Pure, 1 kgMSDS
C-0641-00LiT/LiM 67/33, Ultra Pure, 1 kgMSDS
C-0641-60LiT/LiM/LiBr 66.67/32.83/0.50, Ultra Pure, 1 kgMSDS
C-0641-70LiT/LiM/LiI 66.67/32.83/0.50, Ultra Pure, 1 kgMSDS 
C-0650-00LiT/LiM 35/65 (12/22), Pure, 1 kgMSDS
C-0650-10LiT/LiM, 35/65 (12/22), powder flux, pure 500 gMSDS
C-0650-60LiT/LiM/LiBr 34.83/64.67/0.50 (11.94/21.89/0.17), Pure, 1 kgMSDS
C-0650-70LiT/LiM/LiI 34.83/64.67/0.50, Pure, 1 kgMSDS
C-0651-00LiT/LiM 35/65 (12/22), Ultra Pure, 1 kgMSDS
C-0651-60LiT/LiM/LiBr, 34.83/64.67/0.50 (11.94/21.89/0.17) , ultra pure, 1 kgMSDS
C-0651-70LiT/LiM/LiI 34.83/64.67/0.50, Ultra Pure, 1 kgMSDS 
C-0685-00Boric acid, ultra pure, 500 g
C-0690-00Lithium Carbonate, Powder Flux, Ultra Pure, 500 gMSDS 
C-0695-00Sodium carbonate, ultra pure, 500 gMSDS
C-0910-00Sodium nitrate, powder, 500 gMSDS

Oxidizers and Non-Wetting Agents Catalog

Catalog NumberFluxMSDS
C-0700-00Potassium Iodide, NWA - Crystal, 100 g
C-0700-01Potassium Iodide, NWA - Crystal, 250 g
C-0701-00Potassium Iodide, NWA - Solution, 15 ml Bottle
C-0701-01Potassium Iodide, NWA - Solution, 15 ml Bottle (10-Pack)
C-0710-00Lithium Bromide, NWA - Crystal, 100 gMSDS
C-0710-01Lithium Bromide, NWA - Crystal, 250 gMSDS
C-0711-00Lithium Bromide, NWA - Solution, 15 ml Bottle
C-0711-01Lithium Bromide, NWA - Solution, 15 ml Bottle (10-Pack)
C-0720-00Lithium Iodide, NWA - Crystal, 100 g
C-0720-01Lithium Iodide, NWA - Crystal, 250 g
C-0740-00Sodium Iodide, NWA - Crystal, 100 gMSDS
C-0740-01Sodium Iodide, NWA - Crystal, 250 gMSDS
C-0800-00Lithium Fluoride, Crystal, 100 g
C-0800-01Lithium Fluoride, Crystal, 250 g
C-0900-00Lithium Nitrate (LiNo3) 500 gMSDS
C-0910-00Sodium Nitrate (NaNo3) 500 gMSDS