CN103131650A - Eosino-thiobacillus and application thereof to copper pyrites leaching - Google Patents

Abstract

The invention discloses an extreme acidophilic thiobacterium named Acidithiobacillus sp. ZJJN, and the preservation number is: CCTCC NO: M2012104. The bacteria showed strong sensitivity to various antibiotics and high tolerance to several common metals in the bioleaching process. In addition, the bacteria and Thiobacillus ferrooxidans were used to leaching chalcopyrite at extreme pH, and it was found that compared with the control system, the recovery rate of copper was greatly improved. Scanning electron microscopy was used to observe the surface of the leached chalcopyrite, and it was found that the jarosite on the surface of the chalcopyrite added with the strain ZJJN system was greatly reduced, and the leaching efficiency was greatly improved. The extreme acidophilic thiobacterium of the present invention can tolerate an extremely low pH environment, is very suitable for leaching chalcopyrite leaching systems, and is expected to be applied to industrial leaching of chalcopyrite.

Description

A Acidophilus Thiobacillus and Its Application in Chalcopyrite Leaching

technical field

The invention relates to a strain of acidophilic thiobacillus, in particular to a strain of extreme acidophilic thiobacterium and its application. the

Background technique

Bioleaching is an interdisciplinary subject in the field of biology and metallurgy, also known as biooxidation or biohydrometallurgy, that is, using microorganisms, air and water and other natural substances to leach lean ore, waste ore, tailings and smelting slag, etc., to recycle Certain precious non-ferrous metals and rare metals are a metallurgical method to prevent the loss of mineral resources and maximize the use of mineral deposits; compared with traditional smelting methods, bioleaching usually has less infrastructure investment, low operating costs, and less environmental pollution. Lower-grade minerals can be processed, so it is considered a green metallurgical technology. the

Primary sulfide copper ore chalcopyrite is the most stable and difficult copper mineral to be leached. The leaching cycle is usually longer than 1 year, and the leaching rate is less than 30%. As a result, a large amount of low-grade chalcopyrite cannot realize economic value if traditional techniques are used. . More than 70% of the existing copper minerals in the world are low-grade chalcopyrite. With the reduction of high-grade ores and the increase of demand, the industrial leaching of such minerals has become a hot and difficult point of current research. the

Although it has been reported in China in recent years that optimizing the bacterial community structure can further improve the leaching efficiency of chalcopyrite, due to the presence of a large amount of iron ions in the leaching system, a large amount of jarosite will inevitably be produced during the leaching process. The denseness of the precipitate is very good, and it will be tightly wrapped on the mineral surface, which prevents the contact between microorganisms and the mineral surface, and affects the leaching efficiency. Recent studies have pointed out that controlling the lower pH (<1.5) will reduce the formation of jarosite precipitation, but the optimum pH of common leaching bacteria, such as Thiobacillus ferrooxidans, is 1.8-2.5, and too high acid will reduce Bacterial concentration during the leaching process, thereby reducing the leaching efficiency. the

Therefore, it is very important to screen and identify Thiobacillus extreme acidophilus and apply it to the leaching of chalcopyrite, so as to reduce the formation of jarosite precipitates and further improve the efficiency of chalcopyrite entry and exit. the

Contents of the invention

The main purpose of the present invention is to provide a strain of extreme acidophilic Thiobacillus and its application in chalcopyrite leaching in view of the above existing problems and deficiencies. the

In order to achieve the above object, the present invention provides a strain of acidophilic Thiobacillus, which is screened from the biological heap leaching pool of Fujian Zijinshan Copper Mine and obtained through artificial selection, named as acidophilic Thiobacillus ZJJN (Acidithiobacillus sp. ZJJN), which is rod-shaped, Gram-negative, very numerous flagella, and thick capsule. It was preserved in the China Center for Type Culture Collection (CCTCC) on April 9, 2012. The strain preservation registration number is: CCTCC NO: M 2012104, and the preservation address is Wuhan University, Wuhan, China. The optimal growth pH of the bacteria is only 0.5-1.5, and it can grow in the medium of pH 0. It can maintain a more acidic environment in the chalcopyrite leaching system, effectively reducing the production of Thiobacillus ferrooxidans on the mineral surface. Passivation effect, improved leaching. the

Another technical problem to be solved by the present invention is to provide a physiological and biochemical identification method for the bacteria and investigate the sensitivity and tolerance of the above bacteria to several antibiotics and heavy metal ions. The temperature range is 25-30°C, and the optimum pH range is 0.5-1.5. Under optimal temperature and pH conditions, ferrous ions cannot be utilized, and reduced sulfur elements can be efficiently utilized. Under the transmission electron microscope, the cells are rod-shaped, surrounded by dense flagella, and surrounded by a thick capsule. After 16S rRNA identification, the genetic relationship between ZJJN and acidophilic Thiobacillus thiooxidans exceeded 99%. The order of sensitivity to antibiotics is: tetracycline > streptomycin > erythromycin > chloramphenicol > kanamycin > ampicillin; the order of tolerance to heavy metal ions is: copper > manganese > nickel > zinc Lead > Cobalt. the

Another technical problem to be solved by the present invention is to provide a method for chalcopyrite leaching by extreme acidophilic bacteria using sulfur as an energy substrate, so as to eliminate the jarosite produced in the leaching process and improve the leaching efficiency. Its characteristic is that ZJJN and a strain of Thiobacillus ferrooxidans ATCC23270 are used to leaching poor chalcopyrite ore in Tonglingshan, Anhui Province, which greatly improves the leaching efficiency, which is 80% higher than the leaching efficiency of pure bacteria system. On the surface of minerals, it was found that the precipitation of the mixed and leached minerals on the surface of the minerals was greatly reduced. the

The bio-heap leaching pool of Fujian Zijinshan Copper Mine is a liquid that has been leached through lean ore heaps. Preferably, it is rich in iron ions and other heavy metal ions, and its pH is only 0.8, which is suitable for the growth of extremely acidophilic microorganisms. the

Compared with other common biometallurgical strains, the bacterial strain provided by the present invention can tolerate higher acid, can grow in an extremely acidic environment with a pH of 0, and can better adapt to chalcopyrite leaching systems. The bacterial strain provided by the invention can efficiently utilize the reduced sulfur, and can effectively reduce the film surface passivation produced in the chalcopyrite entry and exit process. In addition, the bacterial strain provided by the present invention can realize strong acid leaching, greatly reduce the formation of jarosite, and the efficiency of leaching chalcopyrite mixed with other common biometallurgical strains is 80% higher than that of the Thiobacillus ferrooxidans leaching system. ,

Description of drawings

Fig. 1 is the cell morphology under a transmission electron microscope using the extreme acidophilic thiobacterium of the present invention. the

Fig. 2 is the change of copper ions in the leaching process of chalcopyrite ore leaching by using Thiobacillus extreme acidophilus and Thiobacillus ferrooxidans in cooperation with Thiobacillus ferrooxidans of the present invention. the

-未调初始pH的混菌；★-初始pH调到1.0的混菌。  ■-Blank control; ◆-Pure Thiobacillus ferrooxidans; ▲—Pure ZJJN bacteria

- Mixed bacteria with no initial pH adjustment; ★ - Mixed bacteria with initial pH adjusted to 1.0.

Fig. 3 is a scanning electron microscope picture of chalcopyrite ore leaching using Thiobacillus extreme acidophilus and Thiobacillus ferrooxidans in cooperation with Thiobacillus ferrooxidans of the present invention. the

A blank control; B pure Thiobacillus ferrooxidans; C mixed bacteria with unadjusted initial pH; D mixed bacteria with initial pH 1.0. the

Detailed ways

Example 1 strain screening

In this example, 100mL of the wet leaching heap of the Zijinshan Copper Mine in Shanghang County, Fujian Province was taken, and the large particles were first filtered with filter paper, and then the filtrate was added to a 250ml Erlenmeyer flask containing 1% chalcopyrite, at 30°C, 170r/h Min, carry out enrichment culture for 4 days, repeat 3-4 times, use Starky-Na ₂ S ₂ O ₃ 5H ₂ O medium for plate separation, after 2 weeks, colonies are formed, and single bacteria are picked and dropped into Starky-S ⁰ culture basal culture, repeated plate isolation 4 times to obtain pure bacteria.

Embodiment 2 strain identification

The entire genome of the pure culture was extracted using the Bacterial Whole Genome Rapid Extraction Kit, and PCR was performed with 16S rDNA universal primers to identify the strain as Thiobacillus acidophilus. the

Physiology, biochemistry and resistance research of embodiment 3 bacterial strains

The morphology of the above ZJJN observed by transmission electron microscopy is shown in Figure 1. Take 10°C, 20°C, 25°C, 30°C and 45°C for the culture of the strains screened to determine the optimum growth temperature is 30°C; take initial pH 0.5, 0.8, 1.0, 1.5, 2.0 and 2.5 at the optimum The culture is carried out at a temperature, and the optimum growth pH range is determined to be 0.5-1.5. Determine the optimal energy substrate (g/l) of strain ZJJN by the following combination: S ⁰ 10.0g, Na ₂ S ₂ O ₃ 5H ₂ O 10.0; FeSO ₄ 7H ₂ O 10.0; FeCl ₂ 10.0; Peptone 10.0; yeast extract 10.0; glucose 10.0; fructose, 10.0; sucrose 10.0; it was determined that ZJJN could not utilize ferrous iron, ferric ions and various organic substances, and its best energy substrate was elemental sulfur.

Using several antibiotics with a concentration gradient of 10 and 100mg/l, it was found that the sensitivity order of ZJJN to several common antibiotics was tetracycline > streptomycin > erythromycin > chloramphenicol > kanamycin > ampicillin; Several heavy metal ions with gradients of 0.5 and 3g/l are found as follows: ZJJN has the order of resistance to several heavy metals: copper>manganese>nickel>zinc-lead>cobalt. the

Embodiment 4 microbial leaching

Chalcopyrite leaching was carried out with sterile, ZJJN pure bacteria, pure Thiobacillus ferrooxidans, ZJJN/Thiobacillus ferrooxidans with unadjusted initial pH and ZJJN/Thiobacillus ferrooxidans with initial pH 3.5. The initial cell concentration was controlled to be 5.0×10 ⁷ cells/ml, the pulp concentration was 10%, 30°C, 170r/min, and the change of copper ions was tested every two days during the leaching process, as shown in Figure 2. The final copper ion concentrations of sterile, ZJJN pure bacteria, pure Thiobacillus ferrooxidans, ZJJN/Thiobacillus ferrooxidans with unadjusted initial pH, and ZJJN/Thiobacillus ferrooxidans mixed bacteria with initial pH 3.5 were respectively 48, 304, 294, 534, and 601mg/l, it can be seen that the mixed bacteria system added with ZJJN has far better ingress and egress effects than the blank and pure bacteria systems. Finally, the leached ore samples were analyzed by scanning electron microscope, as shown in Figure 3, and the precipitation of the mixed leached minerals on the surface of the minerals was greatly reduced.

The leaching rate of the mixed bacteria system with an initial pH of 1.0 was much higher than that of the blank control, the pure bacteria system, and the mixed bacteria system with an initial pH of 3.5, and the jarosite precipitation on the surface was significantly less than that of the pure bacteria system of Thiobacillus ferrooxidans. It shows that ZJJN can effectively inhibit the passivation effect of iron-oxidizing bacteria-Thiobacillus ferrooxidans in the leaching process of chalcopyrite, and can effectively assist Thiobacillus ferrooxidans to improve the leaching efficiency of chalcopyrite. the

To sum up, the extreme acidophilic Thiobacillus acidophilus of the present invention has strong acid resistance, can effectively assist other Thiobacillus ferrooxidans to reduce the jarosite that occurs in the chalcopyrite leaching process, greatly improve the leaching efficiency, and is expected to be used in Hydrometallurgy for large-scale chalcopyrite. the

In this specification, the invention has been described with reference to specific embodiments thereof. However, it is obvious that various modifications and changes can be made without departing from the spirit and scope of the invention. Accordingly, the specification and drawings are to be regarded as illustrative rather than restrictive. the

Claims (5)

1. A strain of Acidithiobacillus sp. ZJJN was deposited in the China Center for Type Culture Collection on April 9, 2012, and the preservation number is: CCTCC NO: M2012104. 2. the screening method of acidic thiobacillus described in claim 1 is characterized in that, sampling in Zijinshan biological heap leaching pool, adopts 1% chalcopyrite to carry out enrichment culture 4 days, repeats 3-4 times, adopts The Starky-Na ₂ S ₂ O ₃ ·5H ₂ O medium was used for plate isolation. After 2 weeks, colonies were formed, and a single colony was picked and cultured in the Starky-S ⁰ medium. The pure bacteria were obtained by repeating 4 times. 3. The acidic Thiobacillus extreme acidophilus described in claim 1 is applied to the extreme environment of acid production, and the optimum pH is 0.5-2.0. 4. The pH of the extreme environment where the extreme acidophilic Thiobacillus acidophilus described in claim 1 is applied to extreme acid production is 0. 5. The acidic thiobacillus extreme acidophilus described in claim 1 is applied to metal smelting.

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