Metakaolin - Cement Pozzolan
Metakaolin - Cement Pozzolan will comprise 25.1% of Kaolin products and 2.1% of all products produced by the Project at full production levels.
High Reactivity Metakaolin (HRM) is a semi-calcined kaolin (at 500-800°C), which is used as a manufactured pozzolan mineral admixture with portland cement to significantly enhance the performance characteristics of cement-based mortars, concretes and related products. Metakaolin (MK) can contribute to increased strength, reduced permeability, greater durability, efflorescent control and control degradation caused by Alkali Silica Reaction.
There is a trend to manufacture optimised engineered pozzolanic materials specifically intended for use in portland cement based formulations. Metakaolin is a leader amongst the new generation of such materials. Concrete producers worldwide recognise the value of pozzolanic enhancement to their products and are increasingly using MK, where available, as a routine concrete ingredient.
Most pozzolans used today are by-products of other industries, such as coal fly ash, or silica fume. Fly ash, at AUD90-140 per tonne, although the least expensive of materials, is increasingly causing concern due to salt efflorescence production in the final concrete product. Silica fume, a by product of silicon metal production, is generally used as a pozzolan in high performance or pre-stressed concretes, i.e. pre-cast components for high rise buildings, structures that require high compressive strength, marine structures, and bridge decks.
In Australia, silica fume is produced mainly by Simcoa in WA at an approximate rate of 10,000-15,000 tpa, for the cement industry (75%) and for the production of refractory castable materials used by the steel-making industry (25%). Some silica fume is exported but as demand has exceeded supply for several years, the export market constitutes a fairly small proportion of production. Production, however, is insufficient to satisfy the demands of the concrete industry. Furthermore, with the depletion of stockpiled silica fume at of the Temco operation in Tasmania, there is an increased shortfall. The shortfall in supply is made up by imports of ~5,000 tpa from Scandinavia and South Africa at a cost of AUD680-700/t.
At a projected sale price of AUD300-550/t, SCM's Metakaolin will compete directly with silica fume in a number of applications. Shotcrete used in mining tunnels is likely to become a market replacing high-priced silica fume and colloidal silica blends. It is likely the shotcrete will use a blend of these three materials.
Metakaolin, in laboratory controlled direct testing within concrete batches, out-performs silica fume. In addition, Metakaolin is fast replacing silica fume in various applications as it results in a white, light coloured concrete, mixes better, is easier to work with, provides a better finish, requires less plasticiser, reduces ASR, and, most importantly, reduces permeability.
Currently, there is no single producer of Metakaolin in Australia. The very minimal amounts being used are fully imported. SCM, therefore, will be the first producer of MK in Australia.
Production of cement in Australia is now controlled by three major cement companies: Cement Australia, Blue Circle Southern, and Adelaide Brighton. These companies account for almost all integrated clinker and hydraulic cement supplies in Australia. They produce in excess of 8 Mtpa.
MK additives for normal usage is as follows:
• 5-10% for compressive structures
• 10-15% for chloride resistance
• 15-20% for optimum chemical resistance and efflorescence control
Assuming an 8% average additive of pozzolanic material in cement, 640,000 tpa will be required. SCM's marketing objective of 25,000 tpa at full production represents only 3.9% of the total annual pozzolan demand. As SCM's MK begins to replace the silica fume market, the overall percentage of the remaining pozzolan market (fly ash), with which SCM will compete, will be reduced. Although fly ash is considerably less expensive than MK, Metakaolin's superior performance characteristics will allow it to compete with fly ash in certain applications. The Company believes that there will be significantly more that 3.9% of the current cement market that would benefit from the addition of Metakaolin in place of fly ash. As such, SCM believes the 25,000 tpa target to be well achievable.
Export of MK to New Zealand, which is approximately one fifth of the Australian market, could account for an additional 5,000 tpa of material sold.
A marketing target of 65,000 tpa of MK represents a 10.2% displacement of the pozzolans market, and given time to develop product awareness in the market, this is not an unreasonable long-term marketing goal. The increased amount of infrastructure projects planned for the Greater Sydney Metropolitan Area (over $18bn in infrastructure in the near future) will consume a large proportion of this 65,000 tpa.
© Sydney Construction Materials 2010