SPECIALIST EQUIPMENT
laboratory in South Africa as a process tool; the technique is now applied to refi ne the process choices. T is has often resulted in the use of more specifi c collectors, more targeted frothers and mineral-specifi c depressants. As ever, sampling and sample preparation
are of paramount important. T e scanning unit uses a polished section of a process sample and then usually takes a scan of 20,000 particles. It is not only important that the sample taken is representative of the process, but also that the sample preparation is rigorous, to eliminate particle
Screenshot of the mineral processing software
size segregation, for example. One of the key factors in the project has been the development of software to accurately defi ne the mineral matrix of a particular orebody. It is only by successfully doing this that testing turnaround time can be reduced to get the feedback to make decisions quickly. T is takes the process from the research to the operational level. Being able to identify the value element loss
in the fi nal tail, and the gangue components in the fi nal concentrate, is important to being able to keep a plant operating effi ciently. T is data is also invaluable in matching the reagent suite to the needs of the plant. How the data is used is crucial to helping in the drive for continuous improvement. T e process mineralogy team should make sure that they use
MLA Dataview software is used to identify mineral losses
the data fi rstly to identify the problem, secondly to form an opinion of why the problem has occurred, and lastly – and most importantly – to off er a solution. As Riaan Grobler, manager of Nasaco and Betachem’s process mineralogy lab says, “Our mantra is: what, why, remedy.” T e process mineralogy team uses the
following method to help their clients maintain an effi cient fl otation operation:
On fi nal fl otation tail: use the MLA data to identify the main mineral lost to tails. T en use the liberation function and the size fi lter function of the MLA Dataview software (part of the FEI MLA Suite software package) to form an opinion as to why the valuable mineral is lost. T e loss is usually due to one of the following
reasons:
● Too small to fl oat ● Too large to fl oat ● Locked in non-fl oating gangue ● Incorrect process or reagent suite to fl oat the value mineral
● Other reasons, including process effi ciency
On the fi nal concentrate: use the MLA data to identify the main gangue mineral in the concentrate. T en use the liberation function and the grouping function of the MLA Dataview software to form an opinion as to why the gangue mineral is present. T is presence is usually due to one of the
following reasons:
● Locked in fl oatable mineral ● Naturally fl oatable mineral in this process and/or reagent suite
● Recovered as entrained fi nes in the fl otation water
● Recovered as a larger particle entrapped in a non-draining froth
● Other reasons, including process ineffi ciency
T e process engineer can now use the data to suggest a course of action to improve the performance. Grobler says, “T e data we obtain from the
MLA helps us in the service we are able to off er through our chemicals. It has made it possible for us to help our clients track their continuous improvement programmes and help with troubleshooting campaigns. It has also made it possible for us to develop new approaches in the chemical solution we are able to off er our clients. We have developed some excellent reagent suite solutions. Process mineralogy is critical for us to help our clients operate effi cient fl otation plants.” ●
For more information ✔ at
www.engineerlive.com/ime Simon Isherwood is with Nasaco.
www.nasaco.ch www.engineerlive.com 45
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