Analysis of the effect of potassium cryolite molten salt on inert anodes

Potassium cryolite molten salt also corrodes the inert anode and side lining materials more severely, and further search for suitable inert anode and side lining materials is needed.

One of the problems with potassium cryolite electrolytes is the low conductivity, which results in a large ohmic drop. Although this can be compensated by adding additives such as LiF and lowering the pole pitch, the additives increase the conductivity while lowering the solubility of alumina and raising the initial crystal temperature, and the lowering of the pole pitch depends on the industrial application of the wettable cathode.

In addition, K+ is enriched at the cathode during low temperature electrolysis, and the mole ratio of electrolyte near the cathode increases, resulting in cathode crusting. High and fluctuating tank voltages and low current efficiency are common in electrolysis with potassium cryolite as the electrolyte. Although the research of potassium cryolite electrolyte has been paid some attention, it is still far from the research of sodium cryolite. The physical and chemical properties of potassium cryolite have only been studied preliminarily and have not been systematized yet, and the available data are few and imperfect, and there are inconsistencies in the data reported in the literature. The existing studies mainly focus on physical and chemical properties such as electrical conductivity, alumina solubility and initial crystallization temperature, but there are very few studies on physical and chemical properties such as density, surface tension and viscosity, so further systematic studies on the physical and chemical properties of potassium cryolite are needed. In addition, the thermodynamic data of potassium cryolite electrolyte system are also lacking, and the understanding of molten salt structure is not deep, all these aspects need to be further investigated.

The industrial application of potassium cryolite electrolytes requires more research on the electrolysis process and optimization of the process, in addition to the search for suitable inert anode materials. In addition, the study of corrosion and permeation of potassium salts on carbon cathodes and wettable inert cathodes is also one of the important conditions for their industrial application.