Identification of Waste Streams through Hydrometallurgy and Characterisation

REQUIREMENT

A titration study of industrial waste produced from a client’s acid chloride production operations was requested. The client would regularly increase the pH of the acid waste to above 9 using lime for repurpose. The requirement was to bring the waste up half pH steps and characterise the solids dropped out by X-ray fluorescence (XRF) and X ray diffraction (XRD) analysis; the liquids were characterised by Inductively Coupled Plasma (ICP) analysis.

The work was largely undertaken using a 20-litre reaction-filter vessel in the Hydrometallurgy Laboratory along with characterisation analysis. The project yielded full characterisations at several pH steps.

IDENTIFICATION OF WASTE STREAMS

The client approached the Institute to utilise our hydrometallurgical vessels and characterisation capabilities to help understand the chemical nature and composition of the solids present in their industrial waste from their acid chloride synthesis process. They already treated their waste using lime to basify it and repurposed its resulting solid precipitate.

The client wanted to understand what compositions would precipitate and discreet pH steps and the nature of individual elements at each pH stage. The proposed work was to take this up, via titration, in sub-pH steps and to characterise the resulting solid via XRF and XRD.

THE CHALLENGE

The client’s blanket approach to fully basifying the material did not exploit any differences in the chemistries of its varying components, creating only one solid at a given composition. This work can be used to formulate new waste treatment plans to gain solid phases that are enriched with desirable elements, by creating an understanding of their precipitation behaviour at different pHs.

THE PROJECT

The client needed a means to perform this reaction at scale and perform the necessary characterisations. By contracting the Institute, they could be provided with use of our new hydrometallurgical vessels and our XRD and XRF instruments. We also provided the expertise to run the experiment.

We performed the titration as well as characterisation of the client’s filter cake solid from their already established basification process.