Abstract

A method has previously been described for the recycling of chrome-tanning liquors. This paper discusses the requirements for introduction of the recycling method into tannery practice and describes problems which have arisen during commercial trials and the factors which are important for successful operation of the process. In particular, control of ionic strength during pickling/tanning with the recycled liquors is vital to maintain leather quality and it has been established that this can be achieved simply by control of specific gravity, despite the progressive change from a chloride to a sulphate pickle system during the process. The advantages of the process are also summarised and these suggest that its adoption is essential under present conditions.