The original beneficiation process of the gold mine was all slime cyanidation CIP process. Because of the change of mining method, the mud content reached more than 15%, which makes the leaching period longer and limited processing capacity; the flotation recovery rate decreased; the production cost became higher. Xinhai needed to change the process to reduce the cost.
After contracting this gold reconstruction project, Xinhai decided to take the test with all slime cyanidation-countercurrent washing-carbon solution method, because the required leaching ore particle of this new process is larger than the process of original process.
The problems of all slime cyanidation CIP process
This process required the leaching ore granularity is fine, -200 mesh accounted for 85%, but the gold mine granularity is coarse, and the mill processing capacity is limited resulting in the entire gold processing decreasing, and the cost of ore dressing increasing; secondly, carbon leaching carbon was weared seriously reaching 120g/t according to Xinhai Research Institute testing; so the overall economic benefits were low.
The all slime cyanidation-countercurrent washing-carbon solution method designed by Xinhai Mineral Processing Research Institute adopted classifying control and thickening before leaching. The details of the test as follow
1. Leaching rate kept stable while the leaching ore particle size was changing in certain range.
Particle size（-200 mesh）% | Grade of crude gold/g | Grade of tailings/g | Gold leaching rate/% |
56.90 | 1.662 | 0.155 | 90.67 |
65.58 | 1.908 | 0.176 | 90.78 |
74.21 | 1.803 | 0.166 | 90.79 |
80.75 | 1.509 | 0.142 | 90.59 |
2. Ore pulp would not become layering with the strong agitation.
3. The low pulp concentration did not affect the leaching because of the simple ore properties and fast leaching speed.
Technology Index Comparison
Process | Max. capacity | Grade of crude gold
/g | Leaching ore particle size（-200 mesh）% | Grade of tailings
/g | Gold leaching rate
/% | Recovery rate
/% | NaCN Consumption
/kg | Power consumption /kw | Steel consumption/kg |
all slime cyanidation CIP | 540 | 1.628 | 85 | 0.180 | 88.94 | 87.16 | 0.45 | 25.79 | 1.85 |
All slime cyanidation-countercurrent washing-carbon solution method | 800 | 1.729 | 65 | 0.181 | 89.53 | 86.86 | 0.35 | 16.94 | 1.25 |
According to the comparison, it showed that the mineral dressing recovery rate was the same, but the cost of all slime cyanidation-countercurrent washing-carbon solution method saved 15.06 Yuan/ton which brought benefits over 3 millon Yuan per year.
Tags:CIP, gold mine
From:Xinhai Mining Machinery Company
