Binderless Briquetting of Collie Coal for Synthetic Rutile Production

The primary objectives of this development program were,

• to construct a semi commercial pilot plant to produce from Collie sub-bituminous coal, dried and binderless briquettes, which provide greater value to metallurgical coal customers (including the synthetic rutile producers of Western Australia), and
• to gather sufficient data upon which to assess the feasibility of a commercial plant to produce such a product.

The development work was carried out with Griffin as Project Manager with further financial and technical support from CSIRO, TraDet and Komarek. The four organisations being referred to as the "technology partners".

Following extensive development work, well beyond the original estimates in terms of time and expenditure, the pilot plant has been able to produce binderless briquettes of adequate mechanical strength for the synthetic rutile producers to conduct a limited evaluation trial.

This report covers the development work up until the evaluation of the synthetic rutile producers' second trial, December 2001.

The synthetic rutile producers carried out two trials. The first trial was conducted in October 1998. This was carried out on a small development kiln with 350 tonnes of the best briquettes from the initial pilot plant configuration. Results obtained indicated that the kiln metallurgical performance improved in line with the expectations of utilising a low moisture coal. However the mechanical strength of the briquettes proved inadequate resulting in excess fines and an unacceptable propensity to spontaneously combust.

The second trial was conducted in October 2001. This was carried out on a commercial kiln with 250 tonnes of briquettes from the reconfigured pilot plant. Results obtained indicated that the kiln metallurgical performance improved in line with the expectations of utilising a low moisture coal. The mechanical strength of the briquettes proved adequate, requiring crushing, resulting in very few fines and no spontaneous combustion during the trial period.

Results were sufficiently encouraging that the synthetic rutile producers are interested in carrying out further trials once the commercial viability of the technology can be substantiated.

The operation of the pilot plant provided sufficient data to model the coal drying circuit for a pre feasibility study. However the data on the briquetting plant cannot be finalised until the briquetting press configuration has been developed further.