Geological Bureau of Guangdong ninth laboratories ore leaching a sulfur molybdenum sulfate, molybdenum immersion uranium extraction and separation, leaching residue flotation, the flotation of water mixed concentrate smelting process, the following products can be obtained: calcium molybdate, molybdenum 40.77%, 85% recovery; diuranate, uranium 70.37%, the recovery rate of 88%; concentrate gold and silver, gold 24.6 g / t, the recovery rate of 90%, silver 490 g / t, the recovery rate 36.8 % (the volatile part is not counted). The radioactive strength of molybdenum products and gold and silver concentrates meets national standards.
1. Characteristics of sulfur-molybdenum ore and properties of a molybdenum uranium deposit
Both sulphide molybdenum and molybdenum ore are molybdenum sulfides (MoS 2 ). The study from the deposit specimen shows that the sulphide-molybdenum ore exists as amorphous or cryptocrystalline minerals, and no single substance can be separated. According to electron probe analysis, it contains 49.66% of molybdenum, 43.59% of sulfur and 6.21.54% of iron . Sulfur-molybdenum ore is very unstable in the oxidation zone and exposed to air, and is easily oxidized into blue-molybdenum ore. Its performance "long white hair, out of the blue sweat." The original ore milled to -200 mesh accounted for about 60% of the blisters for 24 hours, the water solubility rate of molybdenum reached about 9%.
The main metal minerals of a molybdenum uranium mine are sulphur molybdenum ore, blue molybdenum ore and pyrite. It followed sphalerite, Hui copper ore, galena, limonite; throw main gangue minerals and quartz, potassium feldspar, albite, water, mica, potassium alum, kaolin. The sulphur-molybdenum ore is closely associated with pyrite and sphalerite. Uranium minerals mainly exist in the state of ion adsorption and dispersion. Separate uranium minerals (pitchblende, thorianite, molybdenum, uranium yellow, etc.) containing not more than 10% of uranium. Gold-silver ore and sulphide ore such as pyrite zinc ore are symbiotic. The chemical analysis of the ore is shown in Table 1. The molybdenum phase analysis is shown in Table 2.
Table 1 Phase analysis of molybdenum | ||||
project | Total mo | Molybdenum in molybdenum oxide | Molybdenum in molybdenum sulfide | Oxidation rate% |
content% | 0.311 | 0.151 | 0.161 | 48.4 |
Table 2 Chemical analysis of ore | ||||||
project | Mo | U | Au | Ag | Th | K2O |
content% | 0.317 | 0.078 | 1.19 (g / ton) | 66.5 (g / ton) | 0.0025 | 6.9 |
project | Cu | Pb | Zn | Na2O | C | SiO2 |
content% | 0.05 | 0.262 | 0.154 | 0.8 | 0.11 | 72.48 |
project | Al2O3 | TFe | Fe2O3 | FeO | CaO | MgO |
content% | 11.54 | 1.56 | 1.18 | 0.95 | 0.08 | 0.34 |
project | TiO2 | MnO | P2O5 | S | H2O- | Lost |
content% | 0.075 | 0.089 | 0.013 | 0.91 | 0.57 | 2.61 |
2. Characteristics of processing technology of sulfur-molybdenum ore and selection of a molybdenum uranium
The mineral addition process depends primarily on the nature of the ore. The sulphur-molybdenum ore is an amorphous or crypto-crystalline mineral that cannot be separated from a single mineral and is often present as a cemented molybdenum-containing aggregate. Sulfur-molybdenum ore is easily oxidized and dissolved in water, and there are deposits of sulphur-molybdenum ore, and there are often blue-molybdenum ore. Due to these characteristics of sulphur-molybdenum ore, it is difficult to obtain qualified concentrates by general beneficiation methods. A certain molybdenum uranium mine was selected four times by rough selection, and only about 7% of the concentrate was obtained. The water solubility of the blue molybdenum ore and uranium (the solubility rate of molybdenum is 9%, and the water solubility of uranium is more than 1.3%) causes difficulties in flotation water treatment and metal recovery. The single-use beneficiation method can not obtain the qualified concentrate, and the metallurgical method is used to treat the low-grade ore, which is economically uneconomical. Therefore, it is more reasonable to treat the sulphur-molybdenum ore with the combined process of smelting and smelting. [next]
In the research process of some molybdenum uranium deposits, considering the comprehensive recovery of the associated elements of molybdenum and uranium, the former has been subjected to raw material roasting and sulfuric acid leaching, and the sulfuric acid ripening and leaching test, but the leaching effect is not good. According to the symbiotic relationship between the sulphur-molybdenum ore and the blue-molybdenum ore in the ore, and the sulphur-molybdenum ore and the sulphide ore such as pyrite and sphalerite are closely related, the ore leaching of the original ore (leaching of molybdenum oxide) is selected, and the leaching slag is floated. Selection (floating sulphur-molybdenum ore and other sulphide ore), flotation of mixed concentrate ore processing. The test principle flow is shown in the figure below.
3. Separation and smelting test (1) Sulfuric acid leaching test of raw ore The factors affecting the leaching of molybdenum and uranium include sulfuric acid dosage, oxidant, particle size, temperature, time and liquid-solid ratio. The test results show that the main factors affecting the leaching rate of molybdenum and uranium are the amount of sulfuric acid, the amount of oxidant (MnO 2 ) and other factors of temperature. The final process conditions were as follows: acid consumption 6% ore weight, oxidant (MnO 2 ) 1.2% ore weight, leaching time 1.5 to 2.0 hours, liquid-solid ratio 1:1, particle size 0.5 mm. The leaching rate of molybdenum is 58-61%, and the leaching rate of uranium is 87-89. The chemical analysis of the infusion is shown in Table 3.
Table 3 Multiple chemical analysis of immersion liquid | |||||
Ingredients | Mo | U | TFe | SiO 2 | Al 2 O 3 |
Content (g / l) | 1.8 | 0.746 | 2.66 | 0.17 | 1.74 |
Ingredients | K 2 O | P 2 O 5 | AS | SO 4 -2 | Acid |
Content (g / l) | 0.58 | 0.048 | 0.048 | 54.7 | 29.4 |
(2) Extraction and separation of molybdenum and uranium from leachate The components with recovering value in the immersion liquid are mainly molybdenum and uranium. Priority immersion extraction of uranium with 5% P 2 O 4 + 3 % TBP kerosene three countercurrent uranium extraction unsaturated organic phase was washed with 0.75% sodium oxalate was washed three countercurrent molybdenum (pH = 4 ~ 4.5), washed tungsten molybdenum transuranium The organic phase is back-extracted with 10% sodium carbonate brick-level counter-regression uranium, and the stripping solution is used to precipitate ammonium diuranate product with ammonia water. The uranium residual liquid and the washing water of the washing phase are combined in proportion as a raw material for extracting molybdenum. The molybdenum was extracted by a three-stage countercurrent flow of 2.5% N235 + 7.5% TBP kerosene. The molybdenum-saturated organic phase is washed with 15% sulfuric acid, then the molybdenum is stripped with a 2.5% sodium hydroxide solution, and the anti-molybdenum solution is precipitated with lime milk to obtain a calcium molybdate product.
(3) Flotation of acid leaching slag According to the exploration test results and the requirements of flotation concentrates by hydrometallurgy and comprehensive consideration of concentrate grade and recovery rate, a rough and one sweeping process is proposed. The flotation concentrate contains 1.5 to 2% molybdenum for water treatment. In order to improve the recovery rate of molybdenum, gold and silver, a reinforced pharmaceutical system was adopted, and butyl xanthate and black medicine 25 were used as collectors to enrich the sulphur-molybdenum ore, gold, silver and other sulphide ore. The top is a mixed flotation of sulfide ore.
The flotation medium of molybdenum generally uses sodium carbonate as the pulp pH adjuster, and the pulp is alkaline, weakly alkaline and neutral. Since molybdenum, gold, silver and pyrite are closely related, the flotation scheme cannot be determined without considering the flotation of pyrite. Compared with the acid and alkaline flotation medium schemes, the recovery rate of molybdenum, gold and silver is 10-20% higher than that in the alkaline medium. The use of acidic medium flotation can also utilize raw ore to leach residual acid remaining in the ore. Therefore, acidic medium flotation was chosen.
The addition of Na 2 S and CuSO 4 activates the surface oxidized sulfide ore, which is beneficial to the recovery of molybdenum, gold and silver. The amount of water glass has little effect on the recovery rate of molybdenum, but it has a significant effect on the grade of concentrate.
After the condition test, it was finally determined that the grinding fineness - 200 mesh accounted for 99.3%, and the flotation agent dosage is shown in Table 4.
Table 4 Flotation agent system | |||||||
Pharmacy (g / ton) | sulfuric acid | Water glass | Sodium sulfide | Copper sulfate | Butyl xanthate | 25th black medicine | No. 2 oil |
Rough selection | 8300 | 385 | 690 | 230 | 15 | 12 | 75 |
Sweep | - | 231 | 231 | - | 77 | 13 | 32 |
Selected concentrates and sweeping concentrates are combined as a mixed concentrate of molybdenum, gold and silver for leaching flotation. The chemical analysis results of the flotation mixed concentrate are shown in Table 5. The leaching flotation index is shown in Table 6.
Table 5 Multiple chemical analysis of flotation mixed concentrate | ||||||||
project | Mo | U | Au | Ag | Cu | Zn | Pb | K 2 O |
content(%) | 1.6 | 0.0226 | 18.82 (g / ton) | 918.09 (g / ton) | 0.45 | 2 | 3.65 | 5.68 |
project | Fixed charcoal | Ma 2 O | Fe | S | Al 2 O 3 | CaO | MgO | SiO 2 |
content(%) | 0.64 | 0.65 | 9.43 | 11.87 | 9.55 | 0.82 | 0.25 | 48.68 |
Table 6 Flotation indicators | ||||
project | Mo | U | Au | Ag |
index | ||||
Flotation operation recovery rate (%) | 76.5 | 14.3 | 90 | 86.5 |
Recovery rate of raw ore (%) | 30.9 | 1.7 | 90 | - |
(4) Treatment of flotation mixed concentrates The valuable components in flotation mixed concentrates are mainly molybdenum, gold and silver. The sulphur-molybdenum ore and other sulphide ore are converted into oxides which are easily soluble in water or dilute acid by oxidative roasting, and then leached with sulfuric acid to extract molybdenum and uranium by immersion liquid; the leaching residue is gold and silver concentrate.
The calcination temperature of molybdenum is suitably 450-500 ° C. In order to reduce the radioactive contamination of gold and silver concentrate, the calcination temperature is increased to 650 ° C, and the calcination time is 90 minutes. The amount of leaching sulfuric acid is 5 to 8% of the ore weight, the leaching temperature is 80 ° C, the liquid-solid ratio is 1.5, and the leaching time is 30 minutes. The leaching rate of molybdenum is 84.2%, and the leaching rate of uranium is 81.7%. See Table 7 for chemical analysis of immersion and leaching.
Multiple analysis of flotation concentrate leaching and immersion liquid | |||||||||||
project | Mo | U | Au | Ag | Cu | Zn | Pb | TFe | S | SO 4 -2 | Acid |
Leaching content% | 0.337 | 0.0034 | 24.64 (g / ton) | 490 (g / ton) | 0.11 | 0.76 | 4.4 | 11.35 | 1.41 | 　 | 　 |
Infusion content (mg/L) | 6850 | 99.5 | 8.75 | 1968 | 8630 | 9.4 | 1120 | 7988 | 28700 | ||
The flotation mixed concentrate leaching solution extracts molybdenum with 5% N235+12.5% ​​TBP kerosene, the molybdenum containing tungsten and the organic phase washes the uranium with 15% H 2 SO 4 , and the saturated organic phase containing molybdenum after uranium washing with 5% sodium hydroxide The solution is de-extracted with molybdenum. The anti-molybdenum solution contains 35.85 g/L of molybdenum and 4 mg/L of uranium. In order to eliminate the pollution of radioactive molybdenum products, AlCl 3 •6H 2 O is used as a carrier to remove uranium. The molybdenum solution after uranium is heated to 80-90 ° C, neutralized with hydrochloric acid to pH=3~4, and added with lime milk precipitation. Molybdenum, obtaining calcium molybdate products.
The sulphur-molybdenum ore is a sulfide of molybdenum (MoS 2 ), but their structure is different from that of the group, and there is a big difference in properties. Therefore, the sulphur-molybdenum ore is more complicated and difficult to process than the molybdenite. It is economically meaningful to comprehensively recover sulphur-molybdenum ore from the combined process of metallurgy
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