Scalable sampling solutions for in-process particle size monitoring: Stuart Barton, Xoptix (UK)
Filmed at Cemtech Europe 2015, 20-23 September, Intercontinental Hotel, Vienna, Austria.
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Now until recently this fineness has been carried out by various techniques in the laboratory, blaine apparatus, sieves, and actually this must be a very old slide because I've said more recently laser diffraction. Actually laser diffraction has been used in cement plants for more than 25 years.
Okay all these techniques give valuable information, otherwise they wouldn't be used I think that's another fairly obvious statements. I was at the cement plant in the UK a few months ago when I was speaking to the laboratory manager and she hated the laser diffraction instrument, because it gave different answers to the other techniques.
Now, what I said to her is that she should be worried if it didn't give different answers, different techniques by definition, will give different answers. We take for example I need a drink, I'm sorry if I lose my voice halfway through this presentation, I think I'm going down with a cold so that's if I could open this, this is a good start.
Right, okay, that particle has just changed its properties. It's almost the same dimension, but the absorption of that particle by blaine apparatus will be completely different. Different techniques will give different answers, and it's what you do with those answers that define the quality of the data that you receive.
Okay, some of the reasons that laser diffraction has become popular. The measurements are fast and reproducible, instead of one or two parameters, you can get a complete distribution of the particle size. Arguably less operator to operator dependency although some people would dispute that, but of course because a computer is attached to it, computers are very clever things they can crunch numbers very well, it's possible to alternate the system. Some of the disadvantages I spoke about one of them, it's going to give different answers to the some of the techniques.
It's no a do agree so which is correct? Is the safe correct, is the blaine measurement correct, is the laser diffraction correct? The are two possible answers to that, they are all correct or none of them are correct, you choose which one you want for that. So more training is required but the technology is not pretty widely used.
In some cases robotic labs are used for automation and you take the human out of the equation and this potential for more frequent analysis. Obviously, less operated intervention and of course one very important thing, it's possible to measure multi-parameters not just size, you can measure XRF, XRD and particle size, in the same laboratory.
While it's almost online it's not really online, the sampling is still relatively infrequent. So typically every 20 minutes. You're then making more frequent measurements in laboratory instrumentation which was designed not to be used as frequently and hence the reliability of less ragged laboratory equipment was questionable and so not possible to close the loop because of the infrequency of the measurement and it's actually very very expensive.
Okay, now in-process systems have been available for some time, and