Novel Method for Determining the Interfacial Properties of Melt Slags Based on Single Hot Thermocouple Technique

To solve the problem of slow heating rate of traditional surface and interfacial tension test method of molten slag, a fast testing method of interface property is proposed in this paper, which bases on the single hot thermocouple technique (SHIT). The results are compared with those of the sessile drop method and literature. The results show that: 1) Using the capillary action of molten slag on the B-type thermocouple, the contact angle can be obtained quickly. The relative error between the contact angle of the slag and that of the sessile drop method is 0.10%, and the maximum fluctuation range of the repeated experiment is +/- 2.00 degrees. 2) Substituting the contact angle and surface tension of the slag into Young's equation, the interfacial tension between the slag and the B-type thermocouple can be obtained. 3) For the commonly used CaO-SiO2-Al2O3-MgO metallurgical slag system, without flux (CaF2, Na2O), the interfacial tension between slag and B-type thermocouple is less affected by the change of composition. The surface tension of the slag can be obtained by the SHTT method, and the relative error with the literature value is less than 2.94%.