Gold ore carbon leaching gold process is a process in which activated carbon is added to the pulp to simultaneously leaching and adsorbing gold. It is one of the main methods of gold ore beneficiation at present.
The process is developed on the basis of the carbon-in-pulp process (CIP), which combines the two steps of cyanide leaching slurry and activated carbon adsorption into one, reducing the number of leaching tanks, shortening the process flow, and reducing infrastructure investment and production. cost. Generally, the carbon leaching (CIL) process of gold mines mainly includes six stages: pulp removal, concentration before leaching, leaching and adsorption, desorption electrolysis, pyrometallurgy, and activated carbon regeneration.
Before leaching and adsorbing cyanide pulp, it is necessary to remove impurities such as sawdust in the pulp to prevent impurities from adsorbing gold in the pulp, preventing it from being mixed into rich carbon, and blocking pipelines and carbon screens. If necessary, the slurry needs to be concentrated, and a descaling agent is added, which can reduce the scaling on the surface of the activated carbon and the screen.
The level of slurry concentration will not only affect the leaching time, but also affect the suspension state of activated carbon. Therefore, in order to make the pulp reach a suitable leaching concentration, the pulp needs to be dehydrated through a thickener before leaching.
When the overflow concentration of grinding and grading is 18-22%, it is not suitable for direct leaching, and the ore pulp must be concentrated first. At this time, it is recommended to use a high-efficiency thickener with a small footprint and high concentration efficiency.
A major feature of the gold ore carbon leaching (CIL) process is that the gold leaching and adsorption operations are carried out at the same time, and the specification and number of leaching tanks need to be determined according to the processing capacity of the gold ore concentrator.
The impurity-removed and concentrated pulp is pumped into high-efficiency leaching tanks arranged in a ladder shape, and generally 5-12 leaching tanks are arranged in series. Add cyanide to the first one or two leaching tanks, and add activated carbon to the latter leaching tanks. Since sodium cyanide is just added to the first one or two tanks, the amount of leached gold is relatively small, so most gold ore carbon leaching ore dressing plants use the first one or two leaching tanks as pre-leaching tanks, and the latter leaching tanks are leaching adsorption tanks .
At present, the desorption method of gold-loaded carbon is high temperature and high pressure desorption method, that is, under the condition of high temperature and high pressure, anion easily adsorbed by activated carbon is added to the desorption system, and Au(CN)2- is replaced to obtain gold mud and poor carbon. , so as to realize the desorption of gold.
The precious liquid obtained by desorbing the gold-loaded carbon is recovered by ionization to obtain solid gold.
In production practice, most gold ore carbon leaching plants use pyrometallurgy, that is, gold ingots are directly smelted from gold mud obtained through simple pickling and impurity removal operations. After pyrometallurgy, the purity of gold ingots can reach more than 99.99%.
Activated carbon after adsorption and desorption needs to be regenerated to restore its adsorption performance. Usually, after desorption, activated carbon is first pickled to remove accumulations such as carbonates, and after repeated use, it needs to be thermally activated to restore the adsorption activity of activated carbon, and then it can be recycled again. The equipment required for activated carbon regeneration operations mainly includes activated carbon pickling tanks, neutralization tanks, regeneration kilns, fine carbon separation screens, water quenching tanks, etc.
Gold ore carbon leaching (CIL) process has strong adaptability to gold ore and is suitable for most types of gold ore. It has simple process, low investment cost, easy operation and high recovery rate of gold. In production practice, it is recommended to do a good job of beneficiation test, and determine scientific and reasonable process flow and technical parameters according to the results of beneficiation test, and avoid random application or simple copying.
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