Using new 2020 research from Outotec, and the University of Chile (combined), it is possible to get a 60-70% recovery of Copper in a more environmentally effective way from leaching. It's still a slow process, but used less acid.
https://www.mogroup.com/portfolio/copper-pressure-leaching-process/There is a lot of scientific research at universities going on at the moment, into more effective, faster, and environmentally safer copper heap leaching. Here is one geologist's perspective from 2020.
https://pubs.geoscienceworld.org/se...91/Management-of-Copper-Heap-Leach-Projects-AAgglomeration as a pre-treatment to the heap leaching step, seems to be the way the industry is going, and appears to be most effective. I'd assume the CYM science with regard to their IP features some kind of agglomeration step. Recently, the Universities in Chile have had some breakthroughs in this area.
Since CYM's 9th March 2020 release on copper metal plate extraction methodologies, there have been further scientific advancements via university studies in this area, and these are more environmentally friendly, with higher leaching rates. These also involve acid-ferric sulfate heap leaching, with fewer, more tightly controlled column tests, but most importantly with the addition of agglomeration (which has been something of a minor scientific breakthrough).
For Nifty, all of this science is crucially important, because in effect, the new science will either make or break the project, it is the single
critical factor that needs to be understood by investors here.
Copper production by heap leaching, coupled with solvent extraction and electrowinning (SX-EW), is a well-established technology. Copper heap leaching is a rate-dependent process sensitive to copper mineralogy driven by the pH of the leach solution.
LixTRA advanced Chemistry
The primary sulfide minerals of copper have been difficult to leach for the purpose of direct copper extraction. In particular, chalcopyrite has been observed to undergo a type of “passivation” under a variety of oxidative leaching conditions.Over the last 10–15 years, a variety of biological and chemical leaching processes have emerged for overcoming the passivation of chalcopyrite. A number of these processes are now entering commercial production or are approaching this status. The BIOCOP™ process of BHP Billiton has now been commercialized at the Alliance Copper plant in Chile. The Total Pressure Oxidation technology has been implemented by Phelps Dodge at Bagdad, Arizona. The Mt. Gordon copper process and the Sepon copper process both use autoclave processes in the overall metallurgical circuit. In the Mt. Gordon circuit, the autoclave was used to leach copper while at Sepon the autoclave is used to produce acid and ferric sulfate to meet the requirements of an atmospheric leach. CESL and CVRD have completed a feasibility study to apply the CESL copper process in Brazil. PLATSOL™ technology for copper, nickel, cobalt and precious metal recovery is now under final feasibility study for application by PolyMet Mining at the NorthMet deposit in Minnesota, USA.The number of available options for copper recovery from primary sulfides is multiplying. In addition to the above options utilizing stirred reactor leaching, a number of heap leach options for primary sulfides are also emerging.
Gw
