DETERMINATION OF THE BATH RATIO IN ACID ALUMINUM ELECTROLYTE BY FLAMEAAS

A new method is described for the determination of the bath ratio in a cid aluminum electrolyte. In the presence of fluoride ions, excess alu minum fluoride in the sample reacts with the added potassium chloride to form potassium hexafluoaluminate. The remaining potassium chloride is determined by flame atomic absorption spectrometry and the bath rat io can be calculated. The method proposed is simple, without need for sintering or melting of the sample. Other components commonly present in aluminum electrolyte do not interfere. The absolute error is less t han 0.05 bath ratio units. The relative standard deviation is found to be 0.9-3.4% for acid aluminum electrolyte in 2.4-3.0 bath ratio units . The method can be applied to the routine determination of the bath r atio for materials used in the aluminum industry.