Before Deciding On Online Slurry Analysis System for Metallurgical Ops

Online slurry analysis systems can provide accurate, real-time elemental analysis for process control of slurry in Minerals Processing operations. These analysis systems help improve product quality and recovery, as well as lower production costs. They are certainly worth purchasing, but before making a buy, you should ask these three technical questions to see if you need more advanced technology and higher priced equipment:

Must light elements (Z <20 (Ca) be measured?

There are slurry analysis systems that can measure both light and heavy elements. However, since more advanced technology is needed, it is usually more expensive to measure light elements. Because of the higher cost of the technology, you would not normally need to consider the higher priced option unless the project’s unique properties (like measurement of light elements, and unaffected by changes in mineralogy, matrix and particle size distribution) are critical to the success of the project and meet ROI criteria.

Which streams are to be measured?

The streams should be listed into two groups:

Those which are critical for control of the process. This group will normally include the feed, final tailings and each concentrate stream. Possibly individual bank rougher concentrates can fall into this category.
Those which are not critical for control but which will allow a better understanding of trends within the process. This group may include the total rougher concentrate and some of the recirculating process streams in the cleaner circuit and cleaner tailing streams.

What elements must be measured in each stream?

Know which elements are critical to your operations. Based on this information, the various trade-offs taking into account all factors between centralized and dedicated analyzers, Prompt Gamma Neutron Activation Analysis (PGNAA) and X-ray Fluorescence (XRF), capital and maintenance cost etc., can be worked out and a recommendation made for the optimum system configuration for the particular plant. [To learn more about PGNAA (prompt gamma neutron activation analysis) and PFTNA (pulsed fast thermal neutron activation), visit the PGNAA and PFTNA Technology page.]
For example, in a nickel concentrator, it is essential to control the concentration of talc (or MgO) in the concentrate stream. To be able to control the concentration of talc in the concentrate requires measurement of Ni and talc in each of the feed, rougher concentrate and final concentrate streams so that the appropriate concentration gradients between these can be optimized and the ratio of Ni/talc can be maximized at each stage for minimum reagent usage.
It may also be useful to measure Fe and S in the feed stream because this may give an indication of the nickel mineralogy entering the plant. In all other streams, it is only necessary to measure Ni because the information from these streams is used only for monitoring the recovery of Ni. Thus, PGNAAA would be required with multiplexing for the three main streams, and possibly a combination of dedicated and multi-stream analyzer (using XRF technology) for the other streams).

There are different types of analyzers, utilizing different technologies, to meet the needs of a particular plant. However, after answering the above questions, you may find that you need a combination of different types of analyzers to fit your requirements. So make sure that whichever vendor you choose, you have the option of mixing and matching equipment and technologies.

You’ll find additional information about online slurry analysis systems in our Frequently Asked Questions page Process Control Considerations for Online Slurry Analysis in Metallurgical Plants FAQs