| This study revealed the reason for gold loss in a gold mine in Inner Mongolia,and proposed solutions based on lab-scale experiments.Firstly,the ore and leaching residue were tested separately on their process mineralogy to find out the cause for gold loss,where XRF,ABS and AMICS were used to detect the mineral composition,chemical composition and mineral dissemination respectively.It was found that some coarse gold grains were not leached completely with surface passivation.The gold distribution in each flow of grinding circuit indicated that free gold particles accumulated in the circuit and a gravity concentration should be set to capture those particles.Secondly,the sample of hydrocyclone underflow was processed by a falcon L40 gravity concentrator with orthogonal method,which presented the optimum efficiency of 66.9% gold recovery and 9.15 g/t captured gold per ton with the operating condition of 60 G centrifugal force and 9 psi backwash pressure.Finally,a series of lab-scale CIL tests were conducted with response surface method to investigate the effects of lime dosage,sodium cyanide dosage and aeration rate on leaching efficiency.Then,the other operating factors were tested.According to those results,leaching efficiency was improved to 94.74% in 36 h with 80% particles passing 38?m,liquid-solid ratio of 1.5,lime dosage of 3.3 Kg/t,sodium cyanide dosage of 1.0 Kg/t,aeration rate of 0.08m3/h,and carbon concentration of 16g/L.This paper may benefit technical optimization of the concentrator and provide reference for other CIL operations. |
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