MIXTURE DESIGN APPLIED TO THE ELECTROCHEMICAL REDUCTION OF CaWO4 TO W

An experiment (mixture) design was created to optimize the process parameters of the electrochemical reduction of CaWO4 to W in molten CaCl2-NaCl eutectic mixture. Temperature, applied voltage and the length of Kanthal wire winding of the CaWO4 pellets were selected as the process parameters that were allowed to vary between the predetermined minimum and maximum values. The rates of the electrochemical reductions were interpreted from the variations of current and total charge vs. time graphs under different conditions. The analysis pointed out that 640 degrees C and 2.81 V resulted in the fastest reduction. Itwas seen that the effect of Kanthal wire winding on the output current was less pronounced when compared to the other two parameters.