Thankfully, the process of agglomeration is a highly effective, economical method to extract precious metals. According to Theo Winterbach, Mechanical and Bulk Materials Handling Manager at SENET, this is one of the key benefits of the agglomeration process – along with its ability to improve the leaching properties on the heap.
What is Agglomeration?
Hugo Bronkhorst, Product Specialist at SENET describes the agglomeration process as a wet process whereby material fines are rolled into uniformed pellets with the aid of binding agents, to achieve the tackiness needed for material to stick to the coarser particles. The efficiency of the heap leaching process relies on the process of quality agglomerate particles. This increases the ore permeability, drives proper percolation, and minimises segregation during the handling and stacking of the agglomerate, prior to loading on the heap leach pad.
“Heap leaching is a relatively low capital investment option for extracting lean-grade metals, like Gold, Nickel, Uranium, or Copper, from the ore body,” confirms Winterbach. “A low operational cost offers the opportunity for new entrants to grow in mining.” He adds that agglomeration is not recommended for high grade ore, which would be better suited to the carbon-in-leach (CIL) extraction process.
The Steps in the Agglomeration and Related Processes
Winterbach simplifies the complex agglomeration and related processes into three steps:
Why Seek Expert Advice for Agglomeration?
It is widely recognised that the efficiency of the heap leaching process relies heavily on the process of quality agglomerate particles. With expert guidance and accurate testing, mines are better able to determine the best process and equipment for extracting their particular precious materials.
“An experience-based approach is critical to success,” believes Bronkhorst. “A myriad of factors influences agglomerate characteristics – from variable drum speed to ore type and moisture content, feed rates and residence times. Agglomeration has the potential to maximise recovery rates, but only if the necessary factors are considered, and the correct processes are followed.”
Blinding the heap with fines means losing the recovery of the precious metals, wasting much energy, and little return on investment. “This is not true agglomeration. Proper processes must be followed to ensure a good agglomerate is added to the heap leach pad. With this approach, the best solution is used to ensure cost savings and maximum profitability,” concludes Bronkhorst.
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