Callidan Instruments, a microwave moisture analysis specialist, has developed a new bulk sample analyser. The MoistScan^® MA-100 uses microwave technology to determine the moisture content of large samples, providing accurate results in quick time. Callidan says that it is an improvement on traditional benchtop instruments as the sample is much larger (it takes a sample of litres), hence more representative, and the result is instantaneous (less than 10 seconds) when compared to traditional methods, which can take up to 10 minutes.

A large smelter in Japan recently purchased an MA-100 to help them better control the granulation process. It has been used to measure the moisture in a lead-zinc concentrate mix fed to the agglomerator. The product granules are also sampled and analysed by the instrument. With this information at their fingertips the plant operators regulate the addition of water to the agglomerator so as to produce granules of the correct size.

The size of the sample is particularly important. Callidan believes that a very small sample size is not a representative sample, even if very stringent sampling procedures are followed. During the course of its normal business of commissioning and calibrating online moisture analysers, Callidan has conducted many hundreds of duplicate sampling programs where laboratory results using small sample sizes have been compared. Inevitably there are significant differences in the moisture results between large and small samples.