1 Thermophilic bioreactor practice
Can be highly exothermic oxidation of sulfide minerals, chalcopyrite and pyrite may be exothermic complete oxidation 2578kJ / mol and 2883lkJ / mol, respectively. The oxidative exotherm of sulfide minerals is conducive to the growth of thermophilic bacteria and promotes the temperature rise of the heap. The temperature of the heap during the mention of the biopile depends on the local climate, temperature, sulfide oxidation rate, liquid distribution and strength, aeration rate and solution evaporation rate. The research on the thermal balance of the heap is sufficient, and there are mathematical models and software. The practice examples of thermophilic bioleaching are as follows.
A Binham Canyon Copper Mine
The copper minerals in the Binham Canyon copper mine are mainly chalcopyrite, with a copper grade of only 0.2% and a pyrite content of 4%. When Kennecott Copper Company studied the heat balance of the Binham Canyon copper mine, it was found that at an altitude of 2070m, the local temperature of 0-20 °C (average 10 °C) in the cold region of 960,000 tons of mines can reach 30-50 °C (high) The local temperature is above 30 °C). The temperature inside the heap (6-12m below the surface of the heap) can reach 60 °C.
B Nifty Copper Mine
The copper minerals in the 85,000 tons test pile of the Nifty copper mine are mainly copper ore and contain a small amount of chalcopyrite. The pyrite content is 3%. A thermocouple was installed at a mine 0.5 to 2.5 m to measure the internal temperature of the heap during the leaching process. It was found that the temperature in the initial stage of leaching (the first 20 days) increased rapidly to 60 °C. During the 120-day leaching period, the temperature of the heap fluctuated at 30-60 °C. The late temperature drop may be due to rapid consumption of pyrite or lack of resistance. Thermophilic bacteria subject to temperatures above 60 °C.
Using the dilution culture count (MPN) to determine the number of bacteria in the culture, the number of mesophilic and medium thermophilic bacteria was very low (10 2 to 10 4 per ml), and the 16S rRNA gene sequence was identified in the isolated strain. Sulfo baci llu s found in the temperature and Fer ro plas m a a cidip hilum , but found thermophiles. Further, the use of fatty acids of phosphorus (microbial PLFA) of ore samples for analysis of a population of microorganisms, the number of bacteria found 5 × l0 6 ~ 6 × 10 7 per gram; Af species found only bacteria, archaea not found. The type of microorganisms in the test pile of the Niffty copper mine is limited, and the lack of thermophilic bacteria may be the reason why the temperature of the heap cannot exceed 60 °C.
C Mo nywa copper mine
The Monywa copper mine in Myanmar, owned by Ivanhoe Mining, is a low-grade secondary copper sulfide mine. Containing 0.4% copper (based on chalcopyrite) and pyrite content 4%. Cathodic copper is produced using a bio-stack immersion-SX-EW process. The agglomeration process is used before the pile is piled up, and the pile is not inflated, and a backhoe pile is used to improve the permeability. The unheated thermocouple of the heap is only measuring the temperature of the ore sample of 2 to 5 m deep, and the sample temperature exceeds 46 °C. A large number of medium thermophilic bacteria were found in the heap, which proved that the heap was not inflated to maintain high temperature and effective leaching of the heap. The pH of the Monywa copper ore leaching solution is generally below 1.5, sometimes below 1.0, the Fe 3 + concentration is 18 g/L, and the heap temperature is greater than 45 °C.
Hawkes et al. used culture and culture-free techniques to analyze microbes on leachate and ore surfaces. We found At.cald u s and L .ferriphilum, Ferop l as ma cupricumulans sulfobacillus and other moderate thermophile. Six pure strains were isolated from the Monywa heap and enriched and cultured at 35 ° C, 44 ° C, and 55 ° C. Enriched cultures were unable to grow at 65 °C. At 55 ℃ Ferroplasma isolated pure culture of the new species was found, start named Fe rro plasma cyprexacervatum, later named Fe rr oplasma  Cup r icu m ulans . The ferrous phase oxidation temperature range of the new strain obtained by the Ratkowsky model was 15-63 °C, and the optimum temperature was 55.2 °C. There is a significant difference from the Ferroplas ma acidiphilum found in the biopreoxidation reactor of Kazakhstan by Golyshina et al. (growth interval 15 to 45 ° C, optimum temperature 35 ° C). There is also a significant difference in the pH range of growth: Fp.cu pricu mulans is 1.0 to 1.2, while Fp. a cidip hilum has an optimum pH of 1.7.
At 35 ℃ not isolated pure iron bacteria, 16S rRNA gene sequence identified as A t. Caldus, obtained at 44 ℃ facultative under culture conditions L. ferriphilu m, L. ferriphilu m at a growth temperature range from 7.5 to 50.9 °C. The optimum temperature Topt is 41.3 ° C, and the optimum pH range is 1.1 to 1.5. The optimum pH is lower than that reported by Okibe et al., L. fer rip h ilum and Coram et al. (1.4 to 1.8) isolated from the pre-oxidation reactor. No thermophilic leaching bacteria found in the Monywa copper ore bioleaching system may have a strict regional relationship with the distribution of thermophilic leaching bacteria.
D Newmont Bio-Preoxidation Heap Leaching
Newmont's 800,000-ton bio-pre-oxidation industrial test heap contains 3.3% to 3.8% sulfur, the average temperature in the heap can reach 52 °C, and the local measurement is 60-75 °C. The presence of bacteria capable of oxidizing iron at temperatures above 65 ° C was not detected in the stack. The temperature of the industrial ore reactor (containing 1.4% to 1.8% of sulfur) put into operation in 1999 was as high as 81 °C. After 6 months of operation, the commercial ore reactor was connected with thermophilic archaea, and the concentration of mesophilic bacteria and medium thermophilic bacteria in the leachate were Thermophilic archaea can be detected in all samples after 10 6 -10 8 ml, after the thermophilic archaea Acidianus and me tallosphaera.
Logan et al., Described in detail in the case of company Newmont Gold Quarry gold ore heap bioleaching preoxidation commercial practice: sulfur ore l.58%, gold 2.6g / t, CaC0 3 3.4% ; local temperature 0 ~ 30 ℃, the leaching liquid pool 20 ~25 ° C, 4 m deep heap 30 ~ 45 ° C, 12 m deep heap 35-55 ° C, the heap temperature fluctuates between 25 ~ 81 ° C (see Figure 5-2); solution redox potential is 710 ~ 760mV (vs.SHE), total iron concentration 8～36g/L, ferrous iron concentration 2～5g/L, pH value 1.3～2.2. 12.6m stack height, oxidation time 164 days, sulfur oxidation rate 22%, gold leaching rate 50%-55%, the consumption of tons of mineral acid is lkg. The leaching microorganisms in the heap include the mesophilic bacteria At. ferrooxidans and Leptospiril lum , the medium thermophilic bacteria Sulfobacillus and the thermophilic bacteria Acidianus, and the ta ll osp h aera .
E Talvivaara black shales containing nickel and cobalt ore heap bioleaching plant tests
The Talvi vaara nickel-cobalt black shale mine is the largest nickel mine in Europe with a reserve of 340 million tons of ore (average 0.27% nickel, 0.02% cobalt, 0.56% zinc , 0.14% copper). Talvivaara nickel sulfide mineral comprising mainly pyrrhotite, pyrite, sphalerite, pentlandite, purple sulfur nickel and chalcopyrite, gangue minerals as quartz, mica, calcium feldspar, plagioclase Stone and graphite ; the main chemical components in the ore are nickel 0.27%, zinc 0.56%, copper 0.14%, cobalt 0.02%, iron 10.3%, sulfur 8.4%, carbon 7.2% and Si0 2 50%. Main value element
The occurrence state is: nickel is distributed in pentlandite (71%), pyrrhotite (21%) and pyrite (8%); cobalt is distributed in pyrite (63%), magnetic yellow iron Mine (26%) and pentlandite (11%); all copper is present in chalcopyrite, and zinc is present in the form of sphalerite.
In the summer of 2005, a semi-industrial test of 50,000 tons of ore bioleaching was started. The ore was broken to P 80 = 8 mm. After the ore mine was put into the yard, the yard area was 50 m × 60 m and the pile height was 8 m. In August, the liquid leaching began. By the end of 2006, the leaching rate reached 94% of nickel, 13% of cobalt, 83% of zinc, and 3% of copper. The pH value of the solution is controlled at I.5~3.0, and the drip strength is 5L/(m 2 .h); the heap and the sump are covered with heat preservation, so that the temperature of the leaching solution is kept at 40-50 ° C, and the temperature of the drip is 20~ 40 ° C (see Figure 5-3). Bioleaching microorganisms include mesophilic At .fe rroo x idans,
L .f erroo xidans and moderate thermophilic At. C a l d us, Sulfobaci ll us, No thermophilic archaea.
2 Zijinshan 10,000-ton biological copper extraction industry practice and its characteristics
Zijinshan Copper Mine is the largest secondary copper sulfide mine in China. It has an average copper grade of 0.43% and a ore volume of 400 million tons. The copper metal reserves are 1.72 million tons (the national land reserve word [2007] No. 001). In December 2005, the commercial mining of the underground mining-bio-pile-SX-EW process with an annual output of 10000t of cathode copper was put into operation. In the four years from 2006 to 2009, a total of 13.8 million tons of ore with an average grade of 0.38% was processed, and the cumulative production of cathode copper was 3.76. Ten thousand tons, the average copper production cost is 14,200 yuan / ton, and the accumulated profits and taxes are 1.2 billion yuan. The bio- heap leaching process was successfully commercialized for the first time in China (see Figure 5-4). The bio-stacking process for the treatment of Zijinshan Copper Mine not only has low production cost, but also shows that it is superior to traditional flotation-flash smelting process in terms of energy saving, water saving and pollutant discharge. .
Compared with most bioleaching commercial mines in the world, the Zijinshan Copper Mine bio-leaching project faces new challenges, including acid iron accumulation caused by high pyrite content, large rainfall, and dense geographical conditions. And demanding environmental requirements. According to the characteristics of Zijinshan copper ore, through the reasonable engineering measures, a characteristic leaching system has been formed in the bio- heap leaching system of Zijinshan Copper Mine: low pH (0.8~1.0), high iron concentration (50g/L), temperature High (leachate temperature 45 ~ 60 ° C), microbial population sulfur bacteria advantage, in the realization of copper efficient leaching, pyrite dissolution is inhibited, iron in the heap into a sputum, to achieve low-cost iron balance; using lime neutralization And membrane technology to deal with acidic wastewater and other measures to achieve external discharge standards.
Table 5-3 lists the operating costs and economic benefits of the Zijinshan Copper Mine from 2006 to 2009; Table 5-4 shows the results of the life cycle evaluation of the copper extraction and traditional process of Zijinshan. Compared with the two processes, the biological copper extraction process The energy consumption, water consumption, greenhouse effect and acidification effect were reduced by 62%, 87%, 62% and 85%, respectively.
Plate Flange is the most popular using flange type, DIN EN1092-1 BS4504 GOST33259-2015 SANS1123 JIS B2220 KS B1503 and ANSI B16.5 both have plate flange type, plate flange pressure for PN6 PN10 PN16 PN25 PN40, ANSI B16.5 rating class for 150 and 300, JIS B2220 and KS B1503 class for 5K 10K 16K 20K, plate flange facing type have flat face, raised face.
Plate Flange manufacturer, plain flange, flat face flange, plate FF flanges, en1092-1 type 01 plate ff flanges
Jinan Hyupshin Flanges Co., Ltd , https://www.iflange.com