CN116640925A - Method for weakening surface passivation effect of low-grade chalcocite by using L-ascorbic acid - Google Patents

Abstract

The invention belongs to the technical field of biometallurgy, and in particular relates to a method for weakening the surface passivation effect of chalcocite by using L-ascorbic acid. The method uses acidophilic Thiobacillus ferrooxidans, Leptospira ferrooxidans and acidophilic ferroplasma bacteria domesticated by chalcocite pure minerals as leaching strains, and bioleaches low-grade chalcocite. , during the leaching process, monitor the pH value and Eh value of the leaching system, and measure it every 24 hours. When the pH value of the leaching system exceeds 1.90±0.05, add sulfuric acid to reduce the pH value to 1.90±0.05. When the measured value exceeds 500±5mV, add L-ascorbic acid to reduce the Eh value to 500±5mV, and the leaching cycle is 20d, and finally realize the use of L-ascorbic acid to weaken the surface passivation effect of low-grade chalcocite and improve the bioleaching of low-grade chalcocite efficiency. It has been determined that the leaching rate of Cu in the present invention can reach 96%.

Description

A method for weakening the surface passivation effect of low-grade chalcocite by using L-ascorbic acid

technical field

The invention belongs to the technical field of biometallurgy, and in particular relates to a method for weakening the surface passivation effect of chalcocite by using L-ascorbic acid.

Background technique

Pyrite is a common associated gangue mineral in the bioleaching process of chalcocite. In the complex leaching system, the Fe ³⁺ generated by the dissolution of pyrite will undergo hydrolysis reaction, and different forms of precipitates will be formed, which will lead to leaching. The pH value of the system changes. During the bioleaching process, the hydrolysis reaction will consume the oxidant Fe ³⁺ required for the oxidation of sulfide ore, resulting in a decrease in the concentration of Fe ²⁺ , the energy material for microorganisms, and affecting the growth and activity of microorganisms; at the same time, iron vitriol produced by the hydrolysis of Fe ³⁺ will precipitate The substance will also attach to the surface of copper sulfide, reducing the dissolution rate of copper, that is, the passivation in the process of copper ore bioleaching.

Relevant researchers have found that the passivation effect of the ore surface during chalcocite bioleaching is closely related to the Eh value in the leaching system. In the bioleaching process of copper ore, the main influencing factors of Eh value are the concentrations of Fe ³⁺ and Fe ²⁺ . Therefore, a reducing agent can be added to the leaching system, so that a large amount of Fe ³⁺ in the leaching system is reduced to Fe ²⁺ , and the reduced Fe ²⁺ can continue to be used as an energy source for bacteria, and Fe ³⁺ continues to oxidize chalcocite; In addition, it can also reduce the formation of ferrite substances, weaken the passivation effect on the surface of copper minerals, and promote the leaching reaction, thereby increasing the leaching rate of chalcocite.

Therefore, based on this, the applicant proposed a method of adding L-ascorbic acid reducing agent to weaken the surface passivation effect of chalcocite. In the middle stage of ^bioleaching , the Fe in the leaching system is promoted to be depleted by adding L-ascorbic acid reducing agent. Reduction to Fe ²⁺ , reducing the generation of passivation products such as ferrite. The invention has great significance for improving the bioleaching rate of chalcocite.

Contents of the invention

The purpose of the present invention is in order to improve the leaching efficiency of chalcocite, and propose a kind of method that utilizes L-ascorbic acid to weaken the surface passivation effect of chalcocite, this method can significantly promote the leaching efficiency that improves chalcocite.

To achieve the above object, the present invention adopts the following technical solutions:

A method for using L-ascorbic acid to weaken the surface passivation effect of low-grade chalcocite, which is acidophilic Thiobacillus ferrooxidans, Leptospira ferrooxidans and acidophilic ferrogenase domesticated through chalcocite pure minerals The mixed strains of bacteria are the leaching strains, and the low-grade chalcocite is bioleached. During the leaching process, the pH value and Eh value of the leaching system are monitored and measured every 24 hours. When the pH value of the leaching system exceeds 1.90± At 0.05, add sulfuric acid to reduce the pH value to 1.90±0.05. When the measured Eh value of the leaching system exceeds 500±5mV, add L-ascorbic acid to reduce the Eh value to 500±5mV. The leaching cycle is 20d, and finally realize the use of L-ascorbic acid to weaken the low-grade Chalcocite surface passivation effect, and improve low-grade chalcocite bioleaching efficiency.

Above-mentioned a kind of method utilizing L-ascorbic acid to weaken low-grade chalcocite surface passivation effect specifically comprises the following steps:

(1) making low-grade chalcocite into powder with a particle size of ≤74 μm;

(2) Put 10mL iron bacteria mixed bacteria solution into 90mL 9K medium, adjust the pH value to 1.8 with sulfuric acid solution, place it in a constant temperature shaking incubator at 30°C and 150r/min for shaking culture, and passage once every 6 days with 10vol% inoculum , when the color of the culture solution changed from light green to reddish brown, the subculture was completed to obtain a subculture culture solution; wherein, the mixed bacteria solution of iron bacteria was composed of 1×10 ⁷ CFU/mL acidophilic Thiobacillus ferrooxidans, 1×10 Composition of ⁶ CFU/mL Leptospira ferrous oxide and 1×10 ⁴ CFU/mL acidophilic ferroplasma;

(3) Take 10 mL of the subculture culture solution obtained in step (2) and put it in a 250 mL Erlenmeyer flask, put it into a constant temperature shaking incubator at a temperature of 30 °C and 150 r/min for shaking culture, and add 90 mL of no Iron 9K medium and 1.0g chalcocite pure mineral, continue to cultivate until the culture medium turns reddish-brown to obtain a primary domesticated bacterial liquid; take 10mL primary domesticated bacterial liquid and place it in a 250mL Erlenmeyer flask, put it in a temperature of 30°C and 150r Vibration culture in a constant temperature shaking incubator, when the bacteria grow to the logarithmic phase, add 90mL iron-free 9K medium and 1.0g chalcocite pure mineral, continue to cultivate until the culture medium turns reddish brown, and obtain the secondary acclimatization bacteria liquid;

(4) Add 2-3g of low-grade chalcocite powder obtained in step (1), 10mL of secondary domesticated bacteria liquid obtained in step (3) and 90mL of iron-free 9K medium in a 250mL Erlenmeyer flask, mix and place in 40±5℃, 180±10r/min constant temperature shaking incubator for biological bottle leaching, the whole leaching cycle is 20d, during the leaching process, the pH value and Eh value of the leaching system are monitored and measured every 24h, when When the measured pH value of the leaching system exceeds 1.90±0.05, add sulfuric acid solution to reduce the pH value to 1.90±0.05, and add L-ascorbic acid solution to reduce the Eh value to 500±5mV when the Eh value of the leaching system exceeds 500±5mV;

Wherein, the Cu grade of the low-grade chalcocite is 0.30%±0.05%;

Wherein, the formulation of the 9K medium is: Liquid A: 3.0g/L (NH) ₂ SO ₄ , 0.5g/L K ₂ HPO ₄ , 0.1g/L KCl, 0.5g/L MgSO ₄ ·7H ₂ O, 0.01g/L Ca(NO ₃ ) ₂ , 800mL deionized water, adjust the pH to 2.0, autoclave at 121°C for 20min; liquid B: FeSO ₄ 7H ₂ O 44.3g/L, 200mL deionized water, adjust the pH value to 2.0, 0.22μm filter membrane filtration sterilization; after the sterilization of 800mL A liquid and 200mL of B liquid mixed and packed;

Wherein, the formulation of the iron-free 9K medium is: 3.0g/L (NH) ₂ SO ₄ , 0.5g/L K ₂ HPO ₄ , 0.1g/L KCl, 0.5g/L MgSO ₄ ·7H ₂ O, 0.01 g/L Ca(NO ₃ ) ₂ , 100mL deionized water, adjust the pH value to 2.0, and autoclave at 121°C for 20min;

Wherein, the concentration of the sulfuric acid solution is 50% v/v;

Wherein, the concentration of the L-ascorbic acid solution is 100g/L.

The application of the method of using L-ascorbic acid to weaken the surface passivation effect of low-grade chalcocite ore in the bioleaching of low-grade chalcocite ore.

Significant advantage of the present invention is:

The invention has short technological process, simple operation, simple equipment and low energy consumption, and can significantly increase the bioleaching rate of chalcocite. It is determined that after 20 days of leaching, the Cu leaching rate can reach up to 96%.

Description of drawings

Fig. 1 is a process flow diagram of the present invention.

Figure 2 shows the pH measurements of the present invention.

Fig. 3 is the measured value of Eh of the present invention.

Fig. 4 is the graph of copper leaching rate of the present invention.

Detailed ways

In order to make the content of the present invention easier to understand, the technical solutions of the present invention will be further described below in conjunction with specific embodiments, but the present invention is not limited thereto.

In the present invention, the formula of the 9K medium is: Liquid A (g/L): 3.0g/L (NH) ₂ SO ₄ , 0.5g/L K ₂ HPO ₄ , 0.1g/L KCl, 0.5g/L MgSO ₄ 7H ₂ O, 0.01g/L Ca(NO ₃ ) ₂ , 800mL deionized water, adjust the pH value to 2.0, autoclave at 121°C for 20min; liquid B: FeSO ₄ 7H ₂ O 44.3g/L, deionized 200mL of ionized water, adjust the pH value to 2.0, filter and sterilize with a 0.22μm membrane filter; mix 800mL of the sterilized A solution and 200mL of the B solution, and dispense.

In the present invention, the formulation of the iron-free 9K medium is: 3.0g/L (NH) ₂ SO ₄ , 0.5g/LK ₂ HPO ₄ , 0.1g/LKCl, 0.5g/L MgSO ₄ ·7H ₂ O, 0.01g/L Ca(NO ₃ ) ₂ , 1000mL deionized water, adjust the pH value to 2.0, and autoclave at 121°C for 20min.

In the present invention, the multi-element analysis results and copper chemical phase analysis results of the low-grade chalcocite are listed in Table 1 and Table 2.

Table 1 The multi-element analysis results (%) of low-grade chalcocite

components Cu S TF As Pb Al ₂ O ₃ SiO ₂ CaO MgO K ₂ O Na ₂ O Zn content 0.30 5.03 4.23 0.074 0.079 12.34 76.66 0.13 0.01 1.05 0.087 0.01

The copper chemical phase analysis result (%) of table 2 low-grade chalcocite

In the present invention, the multi-element analysis results of the chalcocite pure mineral are listed in Table 3.

Table 3 Multi-element analysis results of chalcocite pure minerals

In the present invention, there is no special limitation on the sources of the three kinds of iron bacteria, acidophilic Thiobacillus ferrooxidans, Leptospira ferrooxidans, and acidophilic ferroplasma, and the source of iron bacteria known in the art is Yes, specifically, the three iron bacteria in the examples of the present invention were isolated from the acid pit water of the Zijinshan sulfide mine in Longyan City, Fujian Province.

In the present invention, Ohaus ST3100 acidity meter is used for pH value measurement, METTLER TOLEDO potentiometer is used for Eh value measurement, and iCAP7400 inductively coupled plasma emission spectrometer is used for copper and iron content measurement.

Test group 1

A method for weakening the surface passivation effect of low-grade chalcocite, carried out as follows:

(1) Process low-grade chalcocite through operations such as crushing, ore grinding, and grading to produce powders with a particle size of ≤74 μm, and carry out quantitative analysis and detection on the representative samples obtained, and the Cu grade is 0.30%;

(2) Put 10mL iron bacteria mixed bacteria solution into 90mL 9K medium, adjust the pH value to 1.8 with 50% (v/v) sulfuric acid solution, place in 30°C, 150r/min constant temperature shaking incubator for shaking culture, every 6d Passage once according to the inoculum amount of 10vol%, and end the passage when the color of the culture solution changes from light green to reddish brown, and obtain the subculture bacterial liquid; the mixed bacterial liquid of iron bacteria is composed of 1×10 ⁷ CFU/mL Bacillus, 1×10 ⁶ CFU/mL Leptospira ferrous oxide and 1×10 ⁴ CFU/mL acidophilic ferroplasma;

(3) Take 10 mL of the subculture culture solution obtained in step (2) and put it in a 250 mL Erlenmeyer flask, put it into a constant temperature shaking incubator at a temperature of 30 °C and 150 r/min for shaking culture, and add 90 mL of no Iron 9K medium and 1.0g chalcocite pure mineral, continue to cultivate for about 6 days until the culture medium turns reddish brown, and obtain a primary domesticated bacterial liquid; take 10mL primary domesticated bacterial liquid and place it in a 250mL Erlenmeyer flask at a temperature of 30°C , 150r/min constant temperature shaking incubator shaking culture, when the bacteria grow to the logarithmic phase, add 90mL iron-free 9K medium and 1.0g chalcocite pure mineral, continue to cultivate for about 6d until the culture medium turns reddish brown, and obtain the secondary Acclimatized bacteria liquid; the secondary domesticated bacteria liquid contains 1×10 ⁸ CFU/mL of acidophilic Thiobacillus ferrooxidans, 1×10 ⁷ CFU/mL of Leptospira ferrooxidans, and acidophilic ferroplasma 1×10 ⁵ CFU/mL;

(4) In a 250mL Erlenmeyer flask, add 2 to 3g of the low-grade chalcocite sample powder obtained in step (1), 10mL of the secondary domesticated bacteria liquid obtained in step (3), and 90mL of iron-free 9K medium, and place at temperature 40±5°C, 180±10r/min constant temperature shaking incubator for bio-bottle leaching, real-time monitoring of the pH value and Eh value of the leaching system, and the entire leaching cycle is 20d;

(6) After the leaching is completed, the leaching system is subjected to solid-liquid separation to obtain the leaching solution and leaching residue, which are tested by ICP. After calculation, the leaching rate of Cu is 66%.

Test group 2

A method for weakening the surface passivation effect of low-grade chalcocite, carried out as follows:

(1) The low-grade chalcocite is subjected to operations such as crushing, ore grinding, and grading to obtain a powder with a particle size of ≤74 μm, and quantitative analysis is performed on the representative sample obtained, and the Cu grade is 0.30%;

(2) Put 10mL iron bacteria mixed bacteria solution into 90mL 9K medium, adjust the pH value to 1.8 with 50% (v/v) sulfuric acid solution, place in 30°C, 150r/min constant temperature shaking incubator for shaking culture, every 6d Passage once according to the inoculum amount of 10vol%, and end the passage when the color of the culture solution changes from light green to reddish brown, and obtain the subculture bacterial liquid; the mixed bacterial liquid of iron bacteria is composed of 1×10 ⁷ CFU/mL Bacillus, 1×10 ⁶ CFU/mL Leptospira ferrous oxide and 1×10 ⁴ CFU/mL acidophilic ferroplasma;

(3) Take 10 mL of the subculture culture solution obtained in step (2) and put it in a 250 mL Erlenmeyer flask, put it into a constant temperature shaking incubator at a temperature of 30 °C and 150 r/min for shaking culture, and add 90 mL of no Iron 9K medium and 1.0g chalcocite pure mineral, continue to cultivate for about 6 days until the culture medium turns reddish brown, and obtain a primary domesticated bacterial liquid; take 10mL primary domesticated bacterial liquid and place it in a 250mL Erlenmeyer flask at a temperature of 30°C , 150r/min constant temperature shaking incubator shaking culture, when the bacteria grow to the logarithmic phase, add 90mL iron-free 9K medium and 1.0g chalcocite pure mineral, continue to cultivate for about 6d until the culture medium turns reddish brown, and obtain the secondary Acclimatized bacteria liquid; the secondary domesticated bacteria liquid contains 1×10 ⁸ CFU/mL of acidophilic Thiobacillus ferrooxidans, 1×10 ⁷ CFU/mL of Leptospira ferrooxidans, and acidophilic ferroplasma 1×10 ⁵ CFU/mL.

(4) In a 250mL Erlenmeyer flask, add 2 to 3g of the low-grade chalcocite sample powder obtained in step (1), 10mL of the secondary domesticated bacteria liquid obtained in step (3), and 90mL of iron-free 9K medium, and place at temperature 40±5°C, 180±10r/min constant temperature shaking incubator for biological bottle leaching, real-time monitoring of the pH value and Eh value of the leaching system, the whole leaching cycle is 20d; during the leaching process, the pH value and Eh value of the leaching system The value is monitored and measured every 24 hours; after each measurement, when the pH measurement value of the leaching system exceeds 1.90±0.05, the pH value is controlled at 1.90±0.05 with 50% (v/v) sulfuric acid.

(5) After the leaching is completed, the leaching system is subjected to solid-liquid separation to obtain leaching liquid and leaching residue, and ICP detection is carried out. After calculation, the leaching rate of Cu is 75%.

Test group 3

A method utilizing L-ascorbic acid to weaken the surface passivation effect of low-grade chalcocite, carried out as follows:

(1) The low-grade chalcocite is subjected to crushing, grinding, grading and other operations to obtain a powder with a particle size of ≤74 μm. Quantitative analysis and detection is carried out on the representative sample obtained, and the Cu grade is 0.30%.

(2) Put 10mL iron bacteria mixed bacteria solution into 90mL 9K medium, adjust the pH value to 1.8 with 50% (v/v) sulfuric acid solution, place in 30°C, 150r/min constant temperature shaking incubator for shaking culture, every 6d Passage once according to the inoculum amount of 10vol%, and end the passage when the color of the culture solution changes from light green to reddish brown, and obtain the subculture bacterial liquid; the mixed bacterial liquid of iron bacteria is composed of 1×10 ⁷ CFU/mL Bacillus, 1×10 ⁶ CFU/mL Leptospira ferrous oxide and 1×10 ⁴ CFU/mL acidophilic ferroplasma;

(3) Take 10 mL of the subculture culture solution obtained in step (2) and put it in a 250 mL Erlenmeyer flask, put it into a constant temperature shaking incubator at a temperature of 30 °C and 150 r/min for shaking culture, and add 90 mL of no Iron 9K medium and 1.0g chalcocite pure mineral, continue to cultivate for about 6 days until the culture medium turns reddish brown, and obtain a primary domesticated bacterial liquid; take 10mL primary domesticated bacterial liquid and place it in a 250mL Erlenmeyer flask at a temperature of 30°C , 150r/min constant temperature shaking incubator shaking culture, when the bacteria grow to the logarithmic phase, add 90mL iron-free 9K medium and 1.0g chalcocite pure mineral, continue to cultivate for about 6d until the culture medium turns reddish brown, and obtain the secondary Acclimatized bacteria liquid; the secondary domesticated bacteria liquid contains 1×10 ⁸ CFU/mL of acidophilic Thiobacillus ferrooxidans, 1×10 ⁷ CFU/mL of Leptospira ferrooxidans, and acidophilic ferroplasma 1×10 ⁵ CFU/mL.

(4) In a 250mL Erlenmeyer flask, add 2-3g of the low-grade chalcocite powder obtained in step (1), 10mL of the secondary domesticated bacteria liquid obtained in step (3) and 90mL of iron-free 9K medium, and place at a temperature of 40 Biological bottle leaching is carried out in a constant temperature shaking incubator at ±5°C and 180±10r/min. The entire leaching cycle is 20 days. During the leaching process, the pH value and Eh value of the leaching system are monitored and measured every 24 hours; After the first measurement, use 50% (v/v) sulfuric acid solution to reduce the pH value to 1.90±0.05 when the pH measurement value of the leaching system exceeds 1.90±0.05, and use 100g/L when the Eh value of the leaching system exceeds 500±5mV The L-ascorbic acid solution reduces the Eh value to 500±5mV.

(5) After the leaching is completed, the leaching system is subjected to solid-liquid separation to obtain leaching liquid and leaching residue, and ICP detection is performed. After calculation, the leaching rate of Cu is 96%.

The above descriptions are only preferred embodiments of the present invention, and all equivalent changes and modifications made according to the scope of the patent application of the present invention shall fall within the scope of the present invention.

Claims (8)

1. A method utilizing L-ascorbic acid to weaken the surface passivation effect of low-grade chalcocite, characterized in that: acidophilic thiobacterium ferrooxidans, Leptospira ferrooxidans and The mixed strain of ferroplasma acidophilus is the leaching strain, and the low-grade chalcocite is bioleached. During the leaching process, the pH value and Eh value of the leaching system are monitored and measured every 24 hours. When the pH of the leaching system is measured When the value exceeds 1.90±0.05, add sulfuric acid to reduce the pH value to 1.90±0.05. When the measured Eh value of the leaching system exceeds 500±5mV, add L-ascorbic acid to reduce the Eh value to 500±5mV. The leaching cycle is 20d, and finally realize the use of L- Ascorbic acid weakens the surface passivation effect of low-grade chalcocite and improves the bioleaching efficiency of low-grade chalcocite. 2. The method according to claim 1, characterized in that: comprising the following steps: (1) Make low-grade chalcocite into powder with particle size ≤74μm; (2) Put 10mL iron bacteria mixed bacteria solution into 90mL 9K medium, adjust the pH value to 1.8 with sulfuric acid solution, place it in a constant temperature shaking incubator at 30°C and 150r/min for shaking culture, and passage once every 6 days with 10vol% inoculum , when the color of the culture solution changed from light green to reddish brown, the subculture was completed to obtain a subculture culture solution; wherein, the mixed bacteria solution of iron bacteria was composed of 1×10 ⁷ CFU/mL acidophilic Thiobacillus ferrooxidans, 1×10 Composition of ⁶ CFU/mL Leptospira ferrous oxide and 1×10 ⁴ CFU/mL acidophilic ferroplasma; (3) Take 10 mL of the subculture culture liquid obtained in step (2) and place it in a 250 mL Erlenmeyer flask, put it into a constant temperature shaking incubator at a temperature of 30°C and 150 r/min for shaking culture, and add 90 mL of Iron 9K medium and 1.0g chalcocite pure mineral, continue to cultivate until the culture medium turns reddish-brown to obtain a primary domesticated bacterial liquid; take 10mL primary domesticated bacterial liquid and place it in a 250mL Erlenmeyer flask, put it in a temperature of 30°C and 150r Vibration culture in a constant temperature shaking incubator, when the bacteria grow to the logarithmic phase, add 90mL iron-free 9K medium and 1.0g chalcocite pure mineral, continue to cultivate until the culture medium turns reddish brown, and obtain the secondary acclimatization bacteria liquid; (4) Add 2~3g of the low-grade chalcocite powder obtained in step (1), 10mL of the secondary domesticated bacteria liquid obtained in step (3) and 90mL of iron-free 9K medium into a 250mL Erlenmeyer flask, mix and place in 40±5℃, 180±10r/min constant temperature shaking incubator for biological bottle leaching, the whole leaching cycle is 20d, during the leaching process, the pH value and Eh value of the leaching system are monitored and measured every 24h, when When the measured pH value of the leaching system exceeds 1.90±0.05, add sulfuric acid solution to reduce the pH value to 1.90±0.05, and add L-ascorbic acid solution to reduce the Eh value to 500±5mV when the Eh value of the leaching system exceeds 500±5mV. 3. The method according to claim 2, characterized in that: the Cu grade of the low-grade chalcocite is 0.30%±0.05%. 4. The method according to claim 2, characterized in that: the formulation of the 9K medium is: liquid A: 3.0g/L (NH) ₂ SO ₄ , 0.5g/LK ₂ HPO ₄ , 0.1g/L KCl, 0.5g/L MgSO ₄ 7H ₂ O, 0.01g/L Ca(NO ₃ ) ₂ , 800mL deionized water, adjust the pH value to 2.0, autoclave at 121°C for 20min; liquid B: FeSO ₄ 7H ₂ O 44.3g/L, 200mL of deionized water, adjust the pH value to 2.0, and filter to sterilize with a 0.22μm filter membrane; mix 800mL of liquid A and 200mL of liquid B after sterilization, and then pack. 5. The method according to claim 2, characterized in that: the formulation of the iron-free 9K medium is: 3.0g/L (NH) ₂ SO ₄ , 0.5g/LK ₂ HPO ₄ , 0.1g/L KCl , 0.5g/L MgSO ₄ ·7H ₂ O, 0.01g/L Ca(NO ₃ ) ₂ , 100mL deionized water, adjust the pH value to 2.0, and autoclave at 121°C for 20min. 6. The method according to claim 2, characterized in that: the concentration of the sulfuric acid solution is 50% v/v. 7. The method according to claim 2, characterized in that: the concentration of the L-ascorbic acid solution is 100g/L. 8. The application of the method as claimed in claim 1 in low-grade chalcocite bioleaching.