The CIP (carbon-in-pulp) process in gold production is a highly efficient gold extraction technology. It mainly dissolves gold through cyanide leaching to form a gold-cyanide complex, then uses activated carbon to selectively adsorb gold, and finally recovers gold through desorption and electrolysis.
Gold CIP (Carbon in Pulp) Production Line is a mature process for adsorbing and recovering gold from gold leaching solution. It is mainly suitable for treating oxidized ores or flotation tailings containing fine gold. Its core is to dissolve gold through activated carbon adsorption, and then obtain high-purity gold mud through analytical electrolysis.
(1) Crushing and Grinding
Coarse Crushing: The raw ore is crushed to <50mm by jaw crusher or cone crusher.
Fine Crushing:The ball mill or rod mill further grinds the ore to approximately 0.074mm (200 mesh), liberating the gold particles.
Classification: Separate qualified particles by spiral classifier, and return coarse particles to regrind.
(2) Slurry preparation
Mix the finely ground ore with water to form a slurry with a concentration of 35%-45% (weight of solids).
Add lime (CaO) to adjust the pH to 10-11 to inhibit the volatilisation of cyanide and neutralise the acid.
(3) Cyanide dissolution of gold
Pump the slurry through 4-8 leaching tanks in series, simultaneously adding NaCN solution to maintain 0.02%-0.05% concentration.
Add air or oxygen to trigger the leaching reaction, maintaining the process for 24-48 hours to fully dissolve the gold as Au(CN)?? complexes.
(4) Carbon slurry mixing
The carbon-in-leach process introduces 6-16 mesh activated carbon (coconut/apricot shell) into the slurry at 10-25g/L.
Air lifters or mechanical agitators ensure complete charcoal-slurry contact, facilitating gold complex adsorption into the charcoal's porous structure.
(5) Multi-stage countercurrent adsorption
The slurry and activated carbon flow countercurrently in 5-7 adsorption tanks:
Fresh charcoal is added to the last tank to adsorb residual gold.
The system discharges gold-loaded carbon (adsorption capacity: 3000-6000g/t) from the first adsorption tank.
The adsorption time for each stage is 1-2 hours and the total adsorption rate is >95%.
(6) Gold-carrying charcoal screening and washing
The vibrating screen separates gold-loaded charcoal from the slurry, which then returns to the leaching system.
The purification process cleanses gold-saturated charcoal using 3%-5% hydrochloric acid, dissolving calcium carbonate and unwanted particulates.
(7) Electrolytic desorption
Electrolytic method (commonly used):
The process loads the gold-bearing charcoal into the desorption column and pumps a 90-110°C solution (1% NaOH + 0.1% NaCN) through the system.
Applying current desorbs the gold complexes and deposits them electrolytically onto the cathode steel wool, forming gold sludge.
(8) Carbon regeneration
The regeneration process treats the desorbed lean carbon by soaking it in 5% nitric acid, followed by thermal activation at 500-700°C in a rotary kiln to recover adsorption performance.
(9) Gold sludge treatment
The refining process treats electrolytic gold sludge with diluted nitric acid, dissolving residual copper, zinc, and other impurities."
After drying, add borax + sodium carbonate flux, and melt into crude gold ingot at 1200℃.
(10) Electrolytic refining
The process employs crude gold for the anode and a pure gold sheet for the cathode, placing both in a HAuCl? electrolyte solution.
The anode is dissolved and pure gold (purity ≥99.99%) is precipitated at the cathode.
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The CIL (carbon-in-leach) process used in gold production is a gold extraction technology that simultaneously performs cyanide leaching and activated carbon adsorption.
Gold mining equipment is mainly used for separating gold ore in mineral processing industry, and the methods of processing gold ore are flotation, magnetic separation and re-election.
The gold gravity separation process is a traditional method that utilizes the density differences between minerals to separate gold. It is particularly suitable for the coarse-grain recovery of placer gold, vein gold ore, or associated gold.
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