LEVEL AND SOLIDS PROFILE DETECTION IN THICKENERS USING CONDUCTIVITY

Solids concentration (weight % solids) profiles and the clear liquid/s lurry interface level (mud-line) were determined from conductivity mea surements in thickeners at Falconbridge's Strathcona mill (Ni concentr ate and non-mag thickners) and Kidd Creek Division (Cu, Zn concentrate s and final tails in the concentrator and a jarosite thickener in the Zn plant). The conductivity measurement system consisted of a probe 1. 5 m in length with 23 electrode cells, a 24-channel relay, a conductiv ity meter and a computer. A conductivity profile is collected which lo cates the mud-line by a sharp change in conductivity. The conductivity measurements are readily converted to solids concentration profiles u sing a model due to Maxwell. The results from conductivity measurement s were compared with direct measurements on local samples obtained usi ng a modified Noranda sampler. It is concluded that the conductivity t echnique is applicable to locate the mud-line and to estimate the soli ds concentration profiles in thickeners. This on-line information coul d improve the operational efficiency of industrial thickeners.