SURFACE TENSION OF MOLTEN ALKALI METAPHOSPHATES V. V. Lisnyak #* * Chemical Department, Kyiv National Taras Shevchenko University, Kyiv, Ukraine (Received 02 Mart 2010; accepted 25 May 2010) Abstract Two molten alkali metaphosphates (LiPO 3 and NaPO 3 ), known components of molten salt baths for electrolytic metallurgical processes, were examined using the ring tensiometry technique. The surface tension of the melts was measured as a function of temperature in Ar atmosphere. The surface tension decreases linearly with increasing of the temperature in the range from 1123 up to 1373 K. The surface tension data obtained were fitted by linear regression and were compared with the available literature data. The reasons of disagreement between values of surface tension taken from the literature and obtained in the present study were suggested. Keywords: Tensiometry; Molten salts; Thermal analysis. # Corresponding author: lisnyak@chem.univ.kiev.ua Journal of Mining and Metallurgy J. Min. Metall. Sect. B-Metall. 46 (1) B (2010) 117 - 121 1. Introduction Molten salt technology implemented into electrolytic metallurgical processes [1, 2] operates with electrochemical and chemical oxidation/reduction in molten salt baths. Among the molten salts, phosphates as components of molten salt bathes are frequently used for the electrowinning, electrorefining, electroplating of refractory metals and electrodeposition of the metal coatings [3–7]. These processes are linked by the general physicochemical characteristics of molten salts that functioned as solvents. Among known literature the Janz molten salt physical properties database [8] is the most comprehensive collection of data on molten salts properties available today. For both fundamental and applied purposes lot of physicochemical properties of different melts were examined up to nowadays. However, limited data on the surface tension Letter to Editor