Presex Corporation Ndak Molybdenum Ore Selection Plant
1 Introduction
The mine is part of the company. Central Canada, British Columbia, beneficiation plant elevation of 1000m. In 1927, the Ndak molybdenum deposit was discovered. In 1965, the ore processing plant was put into operation at 10 kkt/d. After the expansion in 1967, the ore dressing capacity reached 25 kt/d. After expansion in 1976, the ore dressing capacity reached 27 kt/d.
2. Deposits, ores and mining
According to the genesis of the deposit, the Ndak molybdenum deposit is a hydrothermal (porphyry molybdenum) molybdenum deposit. The appearance is a reticular vein.
The ore body produces a hydrothermal alteration zone in the large fault fine-grain filling zone. The ore body is huge, 1800m long, 750m wide, and the thickness ranges from a few meters to more than ten meters. 1967 approved reserves of 240Mt of ore at an average grade 0.15MoS 2, cut-off grade 0.08% MoS 2. By the end of 1983 to maintain ore reserves of 195Mt, of which recoverable resources 138kt molybdenum metal molybdenum.
The main valuable mineral in the ore is molybdenite. Metallic minerals are mainly pyrite, magnetite, a small amount of brass ore. The surrounding rock is a granite porphyry.
Ndak uses a large open pit mining process. The ore dressing process is shown in the figure below.
Tuendaco beneficiation process
3, broken
Adopt a three-stage and one-closed process. The size of the ore is larger, and the final discharge size is -19mm.
Coarse crush: 1 set of 1.1×1.6m rotary crusher , 140mm discharge port, production capacity of 1600t/h·set.
Medium crush: 2 sets of 2130×133mm hydraulic cone crusher , 32mm discharge port, production capacity 700t/h·set.
Finely divided: 2 sets of 2130×130mm hydraulic cone crusher, 13mm discharge port, production capacity 700t/h·set.
Pre-screening before crushing, the fine-cut closed-screen screening mesh is 19mm, and the mining size is -19mm.
Characteristics of crushing process: Pre-screening is added before three times of crushing to reduce the fineness and reduce the amount of crushed ore and improve the crushing capacity. Before the crushing, the vibrating sieve sifts out about 30%-19mm of the total yield of the powder ore directly into the powder bin, but does not work in the middle and fine crushing.
4, rough selection
Five coarse grinding rough selection systems. Rough grinding uses a two-stage grinding process with open rod grinding and closed ball milling systems. The overflow concentration is 40%~42%, and the overflow fineness is 40%~42%-200 mesh, including 14%~17%+48 mesh. It adopts 5 sets of ¢3.8×4.6m rod mills, 5 sets of ¢3.8×4.6m ball mills and 10 sets of ¢760mm hydrocyclone closed circuits.
The rough selection process is simple, one rough and one sweep (substantially only two sections of rough selection, one selection process).
The coarse selection of systems 1, 2, and 3 used 72 units of Akitel flotation machines. The flotation time was 14.7 min each, and the 4th and 5th systems were coarsely selected and replaced with the Denver DR200H flotation machine, and the flotation time was 16.3 min. The five rough-selected tailings were concentrated into one sweep, using the 11-slot Denver DR600 flotation machine with a flotation time of 4.5 min. The Denver DR flotation machine is highly efficient, with a rich ore ratio of 60 to 125 times. [next]
En Dake deposit in the fault zone, eastern mineral ore, the feldspar is by hydrothermal alteration of kaolin, sorting using the above conditions, molybdenum recovery decrease. Reduce the concentration of slurry in production and extend the roughing time (usually 40%).
The crude selection agent system is simple: oil collector (steam oil substitute) 1148/t, Xintex 14g/t, they are added to the rod mill and ball mill to the mine. Pine oil oil 23g / t is added to the ball mill ore discharge. The oil collector was calculated at 70.5 g/kg MoS 2 . Excess oil collectors will defoam, and when not enough, the trapping power will be too weak, which will affect the recovery rate.
Characteristics of rough selection process: (1) Continuous two-stage coarse grinding rod grinding-ball milling system. (2) Centralized sweeping. (3) Thick, sweeping foam combined with continuous selection. (4) Fine tail rewinding, the rough selection section and the selection section cannot be clearly separated.
5, selected sections
Merged into a series. Three-stage re-grinding and five selection processes.
Each of the 1~3 sections is re-grinded with a ¢1.8×3.7m ball mill. The final length of regrind is 50%~90%-9μm.
1~3 times selected Akitel 48 flotation machine, a fine 36 trough, two fine 12 trough, three fine 6 trough. 4, 5 times selected Denver 15 flotation machine, four selected 14 slots, five selected 14 slots.
Nedak is different from the above factories. The grinding medium is not used with gravel, but the steel ball is used. From the product point of view, iron pollution is not obvious.
At the time of selection, only N-sodium metasilicate 105g/t (addition of 2, 3 stages of regrind to the ore) and sodium chloride 15g/t were added. (Add to selected jobs). The molybdenum recovery rate of the selected section is 98%~99%.
When the flotation product contains a high CaO, the calcium is soaked with hydrochloric acid before filtration to make the CaO content less than 0.03%, and the iron content also decreases.
6. Pharmacy system
Drug | Dosage (g/t) | Dosing position |
Fuel oil | 114 | Rod mill, ball mill feed |
Xintex L | 13.6 | Rod mill, sweeping tank |
Pine oil | 22.7 | Ball mill discharge |
N-sodium metasilicate (NaZSi03) | 105 | 2, 3 times regrind machine to mine |
Sodium cyanide (NaCN) | 15 | Featured slot |
7. Mineral processing index
The ore grade: 0.1% Mo, the original ore processing capacity is 27kt/d, the graded overflow fineness is 40%~42%-200 mesh, and the overflow concentration is 40%~42%.
The molybdenum concentrate grade is 54% Mo, 0.02% to 0.05% Cu, 0.03% CaO (after HCl leaching), 2.5% oil, 1.5% to 3.0% water.
The molybdenum concentrate has a molybdenum recovery rate of 84% and a yield of 6350 t/a (Mo).
Ndakco has its own roasting workshop, which uses a m6.0m, ten-layer multi-layer furnace to convert molybdenum concentrate into industrial molybdenum trioxide for sale.
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