This M.A.Sc. work focuses on the development of a sensor to operate at industrially relevant conditions, directly in autoclaves, to generate accurate online free acidity estimates. The main goal is to obtain accurate (within 5% from titrated) free acid estimates at leach temperature while compensating for various metals in solution at high solid loadings. The electrodeless conductivity sensor and calibration technique that were developed in previous work have been improved upon for operation in slurry systems. The sensor operates at temperature on the basis of induction currents and is suitable for very concentrated solutions containing solid dispersions. Three systems have been investigated: limonitic feeds, limonite-saprolite blends, and a converter slag feed. Up to 40 wt.% solids were tested with investigation carried out from 25°C to 260°C. High quality estimates of acidity were produced for all systems studied, with the average difference between measured and titrated acidities being within 5%.

This M.A.Sc. work focuses on the development of a sensor to operate at industrially relevant conditions, directly in autoclaves, to generate accurate online free acidity estimates. The main goal is to obtain accurate (within 5% from titrated) free acid estimates at leach temperature while compensating for various metals in solution at high solid loadings. The electrodeless conductivity sensor and calibration technique that were developed in previous work have been improved upon for operation in slurry systems. The sensor operates at temperature on the basis of induction currents and is suitable for very concentrated solutions containing solid dispersions. Three systems have been investigated: limonitic feeds, limonite-saprolite blends, and a converter slag feed. Up to 40 wt.% solids were tested with investigation carried out from 25°C to 260°C. High quality estimates of acidity were produced for all systems studied, with the average difference between measured and titrated acidities being within 5%.