1 Introduction
The mine is located in Jinxi, Liaoning Province, 32km away from Jinxi Railway Station. The factory is 80~120m above sea level. It is under the China Nonferrous Metal Industry Corporation. In 1933, lead and zinc were developed here, and in 1940, molybdenum was selected. By 1945, the plant selection capacity reached 3000t/d, and in 1959, the plant was expanded to 3000t/d.
Now it has a daily processing capacity of 7000t of mineral production. The annual production of molybdenum concentrate is about 6000t.
2. Deposits, ores and mining
There are two mining areas in Yangjiazhangzi: Songbei, Lingqian and Songbei molybdenum deposits are high-temperature hydrothermal granite porphyry molybdenum deposits. The ore body is subjected to multiple times of hydrothermal fluid to form ore. The average grade is 0.103~0.105% Mo. The amount of molybdenum metal is nearly 10,000 tons.
The Lingqian molybdenum deposit belongs to the skarn type large multi-layer molybdenum deposit. The average grade is 0.156~0.146%.
According to the total reserves of the two mines, it can guarantee the normal production of the factory for 30 years (A+B+C ore), or 51 years (A+B+C+D). If you consider the reserve mine in Lanjiagou, the resources are sufficient.
In the shale skarn ore before the ridge, the molybdenum ore has a good crystal shape, which is embedded in the gangue in a dip-dyed or spot shape, and has a coarse particle size, generally 0.42 to 0.08 mm, which is an unevenly embedded cloth. The molybdenum grade is between 0.15% and 0.08%. Molybdenite addition, the small amount of metal mineral pyrite, yellow copper ore, sphalerite and galena. The gangue minerals are mainly garnet, diopside , calcite and quartz . The ore is hard and has a Platts hardness of 15. It is an easy to choose molybdenum ore.
The metal minerals of the Songbei porphyry molybdenum ore are similar to those of the ridge, except that there are more pyrites. The molybdenum ore is embedded in the ore in a thin aggregate, with a particle size of 0.15~0.02mm and a grade of 0.12%~0.06%Mo. The gangue mineral is mainly feldspar , quartz, calcite and kaolin . The ore has a hardness of 10, which is a more difficult choice of molybdenum ore. The multi-element analysis of ore and the molybdenum phase are shown in Table 1 and Table 2. Mining is open-pit mining.
Table 1 Multi-element analysis of Yangjiazhangzi molybdenum ore (%)
ore | Mo | S | SiO 2 | CaO | Al 2 O 3 | MgO | Sulfate | TiO 2 | Mn | Zn | As | P 2 O 5 | Bi |
Before the ridge Songbei | 0.19 0.095 | 5.8 7.42 | 33.66 40.24 | 31.37 22.05 | 10.08 10.93 | 3.3 3.52 | 2.6 5.14 | 1.5 1.0 | 0.64 1.08 | 0.075 0.27 | 0.01 0.01 | 0.08 0.07 | <0.01 <0.01 |
Table 2 Phase of molybdenum in ore
Mining area | Total molybdenum (%) | Molybdenum oxide (%) | Molybdenum sulfide (%) | Oxidation rate (%) |
Pre-molybdenum ore Songbei Molybdenum Ore | 0.1515 0.100 | 0.0015 0.0042 | 0.15 0.0958 | 1.0 4.2 |
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3. Mineral processing technology
The three-stage and one-closed process of crushing. The coarse crushing is set in the stope. After the coarse crushing, the -300mm ore block is transported by the aerial ropeway to the medium crushing mine silo. The 2.lm standard cone crusher is used in the 2.lm short-head cone crusher and the 1.8×3.6m self-centering center. The vibrating screen is closed. The final crushed product has a particle size of -15 mm.
Grinding and floating with 1 section of coarse grinding, 2 sections of re-grinding (remaining for a period of re-grinding), 8 times of selection, 2 times of rough sweeping (tailing mine waste) fine tail after 4 fine sweeps, tailings to send water and metallurgy, 4 The fine tail is selected by 3 times of fine sweeping, and the tailings are sent to water and metallurgy. The process is shown in Figure 1.
Figure 1 Yangjiazhangzi beneficiation process
There are 8 series of coarse grinding sections, 4 sets of 3.2×3.1m ball mills , 1 set of 3.2×4.lm (3.2×3.1 modified lengthened lm) and 3 sets of ¢3.0×2.0m cone type ball mills. ¢3.2×3.lm mill production capacity is 50t/h·set, ¢3.0×2.0m mill production capacity is 43t/h·set, closed with spiral classifier. The overflow fineness is 55%-200 mesh. The rough grade is 5%~7%Mo.
Re-grinding 1 with 3 sets of ¢3×1.67m cone-type ball mills with a fineness of 75%-200 mesh. Re-grind 2 with a 1.2 x 1.2 m ball mill. [next]
4. Selected tailings hydrometallurgy
There are two selected tailings in the selection process. After the pyrite is selected, the molybdenum is about 0.6%~1.0%. After concentration, it is sent to the water and metallurgy.
The water metallurgy process is shown in Figure 2. The entire process can be summarized into six steps.
Figure 2 Yangjiazhangzi Middle Mine Water and Metallurgy Process
(1) Sodium hypochlorite leaching: The reaction of decomposing molybdenite with a strong oxidizing agent sodium hypochlorite is:
MoS 2 + 9NaClO + 6NaOH → Na 2 MoO 4 + 2Na 2 SO 4 + 9NaCl + 3H 2 O
This is an exothermic reaction. The suitable temperature is between 25 and 35 ° C, the temperature is higher, and sulfides such as Cu and Fe are also oxidized into the solution. At this time, the concentration of NaClO in the immersion liquid is 130 to 140 g/L, and the concentration of NaOH is 50 to 90 g/L.
(2) Calcium sinking: CaCl 2 is added to the filtrate Na 2 MoO 4 filtered after sodium hypochlorite leaching to form calcium molybdate precipitate:
Na 2 MoO 4 +CaCl 2 → CaMoO 4 +2NaC1
CaCl 2 was added before the first mother liquor is adjusted to pH 5 to 6, the amount of CaC1 2 was added was 1.2 times the theoretical amount of reaction, the reaction must be carried out during heating.
(3) Alkali solution: calcium molybdate precipitation is leached with sodium carbonate solution, and the reaction is:
CaMoO 4 +Na 2 CO 3 → Na 2 MoO 4 +CaCO 3 ↓
At this time, other metal ions can only form MeCO 3 precipitates and cannot be dissolved. Molybdenum enters the liquid phase. [next]
(4) Acid precipitation: After adding acid, after pH=0.5~1.95°C, the molybdic acid precipitate is formed:
Na 2 MoO 4 +2HCI → H 2 MoO 4 ↓+2NaC1
(5) Ammonia dissolution: After the molybdenum acid precipitation is added to the ammonia water, it is dissolved to form an ammonium molybdate solution.
(6) Acid precipitation: After filtering the pure ammonium molybdate solution, after adding hydrochloric acid to pH=2.5~3 at 30~40 °C, the white ammonium paramolybdate precipitates. The precipitate was filtered and dried to obtain a product of ammonium paramolybdate.
The Yangjiazhangzi Water and Metallurgical Workshop produces about 40 tons of ammonium paramolybdate per year.
5. Mineral processing agent system (g/t)
Butyl xanthate 5 (rougher); ADDP 5 (rougher); Kerosene 180 (rougher); Oil # 2 175 (rougher); 10 sodium cyanide (1.4 Discover); Knox 36 (Selected 4, 6, 7 times); water glass 1400 (grinding, fine 1, 5, 8 times).
6, mineral processing indicators
The ore grade is 0.15%; the ore processing capacity is 6000t/d; the concentrate grade is 48%; the concentrate molybdenum recovery rate is 80%~84%.
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