Tungsten (W) nanoparticles were synthesised by using a novel low temperature molten salt technique. Na 2 WO 4 and Al were used as starting materials, and NaCl, KCl, and NaF used to form the reaction media. Among the three salts, NaF showed the best accelerating effect in the W formation. When it was used alone, phase pure W could be produced after 4h at 850°C. On the other hand, when it was combined with the other two salts (forming a NaCl–KCl–NaF eutectic salt), phase pure W nanoparticles could be produced at as low as 650°C. As no water-insoluble by-product phases formed in the final samples, acid leaching which has to be used by many other techniques previously proposed, can be avoided. In addition, the by-product NaAlO 2 , happening to be the key intermediate product phase in the Bayer process, could be further used to prepare two important industrial materials Al 2 O 3 and Na 2 CO 3 , adding more value to the molten salt technique developed with this work.