Investigation of column flotation process on sulphide ore using 2-electrode capacitance sensor is presented in this paper. The effect of air flow rate and solid percentage on column flotation process has been experimentally investigated. The purpose of this paper is to understand the capacitance signal characteristic affected by the air flow rate and the solid percentage which can be used to determine the metallurgical performance. Experiments were performed using a laboratory column flotation cell which has a diameter of 5 cm and the total height of 140 cm. The sintered ceramic sparger and wash water were installed at the bottom and above of the column. Two-electrode concave type capacitance sensor was also installed at a distance of 50 cm from the sparger. The sensor was attached to the outer wall of the column, connected to data acquisition system, manufactured by CTECH Labs Edwar Technology and personal computer for further data processing. Feed consisting ZnS and SiO2 with the ratio of 3:2 was mixed with some reagents to make 1 litre of slurry. The slurry was fed into the aerated column at 100 cm above the sparger with a constant rate and the capacitance signals were captured during the process. In this paper, 7.5 and 10% of solid and 2-4 L/min of air flow rate with 0.5 L/min intervals were used as independent variables. The results show that the capacitance signal characteristics between the 7.5 and 10% of solid are different at any given air flow rate in which the 10% solid produced signals higher than those of 7.5%. Metallurgical performance and capacitance signal exhibit a good correlation.