New Generation Low Carbon Refractory Composites Based on Graphite-Exfoliation

Carbon-containing refractory bricks (CCRBs) are one of the most important materials for the iron and steel industry worldwide. One modern steel-making company alone needs to spend over £200M/annum on refractories of which 70-80% are CCRBs. However, current commercial CCRBs contain high level of carbon (>25%C), causing several serious problems, including great heat loss, temperature drop of the molten steel, deformation of steel shells of steelmaking furnaces, nozzle clogging, carbon pickup, emission of green house gases and unnecessary use of excessive amounts of expensive graphite. To overcome these problems, the carbon content in CCRBs has to be reduced to an appropriately low level (ideally <3%C), i.e., the so-called low carbon carbon-containing refractories (LCCRs) have to be developed. In this programme, a simple, straightforward yet novel concept was put forward to develop LCCRs. Based on the proposed technique, the effective surface area of graphitic carbon to cover the oxide grains could be exponentially increased. Consequently, the carbon content could be substantially reduced without compromising properties and performance of the refractory. This programme, in addition to its academic significance, will greatly benefit many important industries, in particular the refractory and steel industries by providing high quality "greener" refractory materials at lower-cost.

1. Impact on the Refractories and Related Industries
If this programme is successful, LCCRs containing minimal level of carbon and having retained/improved properties and performances can be produced and applied, from which several important industries will greatly benefit, in particular, the refractories industry, the steel industry and all users of steel products, thus the economical and social impact of the programme will be major. >£100K of cash and in-kind contribution promised by the industrial collaborators shows the level of importance of this project to industry.
1) Impact on the refractories industry: With successful reduction of carbon level (ideally to <3%), usage of expensive graphite flakes and antioxidants can be substantially reduced, resulting in great saving on raw materials and thus substantial reduction in the overall refractory production costs, e.g., the direct raw materials costs alone could be saved by 15-20%. On the other hand, compared to their high carbon counterparts, LCCRs would retain or have improved properties and performance. This, along with the reduced production costs, would help the UK refractories industry to increase their market share (10-20% by estimate) (UK output of refractories products is currently £500-600M/annum). Furthermore, many techniques developed during this programme, such as the graphite-exfoliation and carbon dispersion, could be used to improve current commercial refractory products and/or to develop other new types of refractory products.
2) Impact on the steel industry: The steel-making industry will benefit greatly from using cheaper, better and low carbon refractories developed. As mentioned above, the direct raw material costs alone could be saved by 15-20%, which means that one modern steel-making company alone could save £20-30M/annum on refractories. Furthermore, with successful reduction of carbon, the heat loss arising from using current high carbon refractories can be reduced, saving thermal energy and improving the efficiency of steel-refining and casting processes. In addition, several serious problems affecting the steel refining and casting processes, in particular deformation of steel shells of furnaces and clogging of alumina-carbon nozzles, can be largely avoided, extending materials service life, decreasing the downtime, and improving steel-making efficiency. These, along with the improved properties and performance of refractories, would lead to substantial reduction in the energy usage and in the steel production costs, thus a "greener" steelmaking process. In addition, the carbon pick-up problem will be alleviated, resulting in high quality clean steel.
3) Impact on the user industries of steel and graphite micro/nano platelets: All users of steel products such as automotive and construction industries will economically benefit from using cheaper and higher quality steel. The social impact from using reliable high quality steel products will also be significant. Although the primary aim of this project is to develop new generation "greener" LCCRs, it may also impact on other areas using graphite micro/nano platelets (e.g. metal/ceramic/polymer composites reinforced by these novel phases used as parts of automobiles, structural components of electronic devices and films for food packaging), thus benefiting more industries and technology communities.

2. Ecological and Environmental Impact
This programme could lead to substantial reduction in carbon usage (by up to ~90%) and refractories consumption, which would, in turn, have environmental benefits from both mining and disposal aspects. Additional environmental benefits could also result from the substantially reduced emission of green house gases as a result of improved thermal efficiency, reduced carbon content, reduced levels of antioxidants, and extended service lives of refractories. which will help the UK (and other countries) meet their targets for reducing greenhouse gas emissions.