Shrinking core models in hydrometallurgy: What students are not being told about the pseudo-steady approximation

There is a significant amount of early work that has been largely forgotten that deals with the validity of the pseudo-steady approximation for liquid-solid reactions. Much of this was originally published in the chemical engineering literature but is highly relevant to hydrometallurgical processes. The purpose of this paper is to summarize some criteria that have been developed by various authors for determining the error associated with use of shrinking core models for liquid-solid systems and to provide an illustrative example using data for a mineral leaching reaction.