4 Benefits of On-Line Particle Analysis for Mineral Processing

In order to extract valuable minerals from naturally occurring ores, the process of comminution and milling must take place to produce materials of an appropriate particle size. This process is critical in order to ensure operating costs stay low and to ensure the minerals extracted are of high value. Traditionally, particle size analysis has been performed through manual measurement, but increasingly the industry is turning towards on-line particle size measurement methods such as laser diffraction. In this article, we’ll look at four reasons that laser diffraction is the optimum method for particle sizing in the mineral processing industries.

1. Quicker and higher ROI

Most studies have confirmed that return of investment for on-line laser diffraction occurs anywhere between six months and a year following installation. The biggest reason for this is that there is much less reliance on manpower; manual analysis methods generally necessitate highly-skilled individuals to be working around the clock, while on-line systems only require occasional intervention from a semi-skilled worker, lowering costs in terms of both time and expertise. These lowered man hours have the added benefit of minimising the risk of hazard material exposure.

2. Greater levels of process control

With off-line measurement, the frequency of analysis is quite low, occurring an average of once or twice an hour. This has the flow-on effect that operational changes are bound to be much less frequent; the operator will receive the data and make a change (perhaps a very large change), and won’t see the outcome of that change until the next analysis. With online particle size analysis, however, there is a constant flow of information, meaning that smaller changes can be made on a more consistent basis.  Additionally, the on-line method of measurement allows for a steadier stream of automated control. Both of these factors lead to more efficient process control.

3. Faster process optimisation

Since finding the optimal particle size is crucial to extracting the most valuable from the ore, the optimal processes must be put in place. Much like discussed above, off-line particle size analysis requires the analyst to wait until several samples have been taken and analysed before they can see the outcomes of their changes. With an on-line particle size analyser, however, this process is much quicker. Assessing new operating scenarios requires nothing more than a new steady state to be established, meaning the changes can be evaluated in minutes.

4. Immediate upset detection

The impact of an upset can be disastrous for the batch, leading to significant loss of profit. To avoid this kind of situation, it’s important to detect problems as soon as possible. With off-line particle size measurement, problems can go undetected for hours, but with on-line methods such as laser diffraction, there is constant monitoring of the process and upsets can be detected as they occur. Rio Tinto, for example, has enjoyed a two year period without unplanned stoppages, and it’s all thanks to their installation of an on-line particle size analyser. Problems are detected and the appropriate action is taken to remedy the situation before it escalates.