CIL and CIP are the two standard processes for extracting gold from ore using cyanide and activated carbon. They sound similar, they are often quoted interchangeably by suppliers, and choosing the wrong one for your ore will cost you recovery for the entire life of the plant.<\/p>\n
This article explains the real difference between them, when each one wins, and what you should test before you commit.<\/p>\n
Both processes do the same two things: dissolve gold into cyanide solution (leaching), and then pull that gold out of solution onto activated carbon (adsorption). The difference is where<\/strong> adsorption happens.<\/p>\n That is the whole architectural difference. Everything else \u2014 tank sizes, carbon transfer systems, desorption, electrowinning, regeneration \u2014 follows from it.<\/p>\n Because CIL adsorbs gold as soon as it dissolves, the gold concentration in solution stays very low throughout the leach. This matters enormously for a certain class of ores.<\/p>\n Preg-robbing ores<\/strong> \u2014 ores containing carbonaceous material, graphite, or certain clay\/shale components \u2014 actively adsorb dissolved gold onto themselves instead of letting it stay in solution. In a CIP circuit, the gold that gets robbed onto the ore is simply lost with the tailings. In a CIL circuit, the activated carbon competes for the gold and usually wins, because it is present from the first tank at high concentration.<\/p>\n If your ore is preg-robbing, CIL is not a preference \u2014 it is the difference between a viable project and one that loses a large share of its gold.<\/p>\n CIP is not obsolete. It has real advantages on the right ore:<\/p>\n In practice, most modern gold plants that handle a mix of ore types are built as CIL, because it is more forgiving. CIP is typically chosen when test work shows the ore is clean and requires no preg-robbing protection.<\/p>\n The choice should never be made on ore type description alone. Before committing to CIL or CIP, you need:<\/p>\n These tests need very little material and can be run before you commit capital. Doing them in the wrong order is how projects end up rebuilding their leach circuit two years after commissioning.<\/p>\n Whichever process you choose, the back end of the plant is essentially the same, and it is where projects are most often under-sized:<\/p>\n Get the regeneration kiln capacity right at the design stage. It is far cheaper than adding capacity later.<\/p>\n Small plants and large plants do not make the same choice. At the smaller end of the range \u2014 tens of tonnes per day \u2014 CIL with a small number of combined leach-adsorption tanks is usually the practical option, because it needs the fewest vessels and the least instrumentation. As throughput grows into the hundreds of tonnes per day and beyond, the extra tanks of a CIP train become an affordable way to buy process control, provided the ore permits it.<\/p>\n If you want to see how the equipment is arranged at each of these scales, our CIP \/ CIL production line page<\/a> lists standard configurations by daily capacity, from 50 t\/d up to 1,000 t\/d.<\/p>\n If you are at the design stage, send us your ore test results \u2014 extraction percentage, reagent consumption, grind size, and whether any preg-robbing behaviour was observed. We will tell you which process fits and give you a tank arrangement and equipment list for your target capacity.<\/p>\n If you have not run the tests yet, we can supply the laboratory equipment<\/a> to do the work at site scale before you commit to a full line.<\/p>\n\n
Why the difference changes your recovery<\/h2>\n
Where CIP still wins<\/h2>\n
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Side-by-side comparison<\/h2>\n
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\n \nFactor<\/th>\n CIL<\/th>\n CIP<\/th>\n<\/tr>\n<\/thead>\n \n Where adsorption happens<\/td>\n In the leach tanks<\/td>\n In a separate adsorption train<\/td>\n<\/tr>\n \n Gold in solution during leach<\/td>\n Kept very low<\/td>\n Builds up to a normal leach profile<\/td>\n<\/tr>\n \n Preg-robbing ore<\/td>\n Handles it<\/td>\n Loses gold to the ore<\/td>\n<\/tr>\n \n Tank count for the same throughput<\/td>\n Fewer, because leach and adsorption are combined<\/td>\n More, because both stages need their own tanks<\/td>\n<\/tr>\n \n Process control flexibility<\/td>\n Lower, but more forgiving<\/td>\n Higher<\/td>\n<\/tr>\n \n Typical application<\/td>\n Mixed and difficult ores, most new projects<\/td>\n Clean oxide ores with completed test work<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n What you must test before choosing<\/h2>\n
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What comes after the leach circuit<\/h2>\n
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How plant scale changes the answer<\/h2>\n
The three mistakes that cost the most<\/h2>\n
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Next step<\/h2>\n