Abstract: A system for automatically and continuously measuring the zinc and sulfuric acid concentration in an electrolyte circulating through electrolysis cells of a hydrometallurgical zinc production system, in which an inductive solution analyzer capable of continuously detecting the conductivity of the circulating electrolyte is used with a measuring cell disposed in the path of a continuous stream of the circulating electrolyte. The measuring cell comprises a defoaming chamber, a measuring chamber and an overflow chamber, and the continuous stream of the electrolyte flows through the measuring chamber as a downward stream so that bubbles can be removed and precipitation of slurry can be prevented. The signal representative of the detected conductivity is applied to an electronic computer which computes automatically the zinc and sulfuric acid concentration according to predetermined calculation formulas.

Abstract: An apparatus for automatically cleaning the electrodes of a pH meter comprising a measuring tank containing a sample solution supplied from a tank of purification section to be subject to measurement of the pH value, a cleaning tank juxtaposed with the measuring tank and having therein a cleaning brush mounted on a rotary shaft, means for supporting the electrodes of the pH meter for vertical movement, and means for supporting the electrodes supporting means for horizontal swinging movement, whereby the electrodes of the pH meter can be moved between the pH value measuring position in the measuring tank and the position engaged by the cleaning brush in the cleaning tank.