CN112391527B

CN112391527B - Method for strengthening biological leaching of copper blue by comprehensively utilizing ferric ions and ferrous ions

Info

Publication number: CN112391527B
Application number: CN202011280755.3A
Authority: CN
Inventors: 王军; 于世超; 刘仕统; 杨宝军; 廖蕤; 洪茂鑫; 邬柏强; 赵春晓; 林豪; 林墨; 刘玉玲; 周祎; 汤安妮; 张雁生; 谢建平; 申丽; 赵红波; 甘敏; 覃文庆; 邱冠周
Original assignee: Central South University
Current assignee: Central South University
Priority date: 2020-11-16
Filing date: 2020-11-16
Publication date: 2021-10-08
Anticipated expiration: 2040-11-16
Also published as: CN112391527A

Abstract

The invention belongs to the technical field of biological metallurgy, and particularly relates to a method for strengthening biological leaching of copper blue by comprehensively utilizing ferric ions and ferrous ions, which can be used for improving the leaching efficiency of low-grade copper sulfide ore. Specifically, ferric sulfate and sulfur oxidizing bacteria are used as a leaching agent to leach copper blue; then adding iron-oxidizing bacteria into the leaching system to realize leaching. The method realizes the efficient utilization of the iron source and bacteria, and avoids the premature generation of passivation substances such as dense jarosite on the surface of the mineral caused by the addition of exogenous iron and the limitation of a sulfur layer formed on the surface in the reaction process on the reaction rate. The invention has important significance for improving the biological leaching efficiency of the chalcocite.

Description

Method for strengthening biological leaching of copper blue by comprehensively utilizing ferric ions and ferrous ions

The technical field is as follows:

the invention belongs to the technical field of biological metallurgy, and particularly relates to a novel bioleaching method for promoting the dissolution of copper blue of refractory secondary sulfide minerals by means of the cooperation of ferric ions and leaching bacteria, which can be used for improving the leaching efficiency of low-grade copper sulfide minerals.

Background art:

copper blue is the main copper-containing mineral in the second stage of chalcocite leaching, and a large number of researches prove that the reaction rate in the second stage of chalcocite leaching is slow, so that the copper extraction efficiency of the chalcocite leaching is greatly limited. Research personnel on the components of the passivation film in the bioleaching process of the chalcopyrite and the bornite also show that the copper blue is one of the components of the passivation film.

By increasing the reaction temperature and increasing the oxidant (Fe) in the system³⁺) The content of copper blue can effectively improve the leaching efficiency of copper blue, and the two factors play a key role in improving the leaching rate of the second stage of the chalcocite. However, for the effective high temperature range of 75-100 ℃ selected by researchers, this condition is difficult to achieve in some heap bioleaching site practices despite the presence of thermophilic strains appropriate for this temperature range. The addition of a large amount of high-valence iron oxidant not only increases the cost of biological leaching of the chalcocite, but also is not beneficial to the growth of iron oxidizing bacteria in a system, thereby influencing the improvement of the leaching efficiency to a certain extent. Fe before the bacteria concentration in the sulfuric acid bioleaching system does not reach the logarithmic phase³⁺The concentration will drop suddenly in a short period, and the sulfur layer deposited on the surface of the chalcocite layer by layer limits Fe to a great extent³⁺Diffusion process of unreacted mineral to the inner layer.

Therefore, the applicant proposes a novel method for strengthening the leaching of the copper blue by means of ferric ions and mineral leaching bacteria, based on the following steps: the method provides a reinforced leaching method of adding leaching reagent step by step, firstly adding ferric iron and sulfur oxidizing bacteria, and then adding iron oxidizing bacteria after a certain time, thereby not only eliminating reaction stagnation caused by accumulation of sulfur as a reaction intermediate product, but also realizing high-efficiency utilization of an iron source and bacteria, and avoiding premature generation of a dense jarosite passivation on the surface of a mineral due to the addition of exogenous iron. The invention has important significance for improving the biological leaching efficiency of the chalcocite.

The invention content is as follows:

the invention aims to improve the leaching efficiency of copper blue, and provides a method for enhancing the leaching of copper blue by utilizing the synergistic effect between exogenous iron and leaching bacteria.

The purpose of the invention is realized by the following modes:

a method for strengthening biological leaching of copper blue by comprehensively utilizing ferric ions and ferrous ions sequentially comprises the following steps:

(1) firstly, ferric sulfate is added into sulfur oxidizing bacteria to leach copper blue;

(2) adding iron-oxidizing bacteria into the leaching system in the step (1) for leaching.

In the method, the raw material is subjected to a chemical reaction,

adding iron oxidizing bacteria after the ferric ions in the step (1) are completely converted into the ferrous ions (after the reaction is carried out for 3-5 days, the ferric ions are completely converted into the ferrous ions, and at the moment, the leaching of the copper ions in the leaching solution reaches about 35% -40%);

and (2) finishing leaching when the concentration of copper ions in the leaching solution phase fluctuates up and down within an interval of less than 5%.

The method is used for leaching Fe in a system³⁺The concentration of (B) is 0.05 to 0.15M, preferably 0.07 to 0.12M, and more preferably 0.1M.

In the method, the leaching reaction temperature is controlled at 30-50 ℃, preferably 42-47 ℃, and further preferably 45 ℃.

The method has the leaching reaction rotating speed of 170-.

The method adjusts the pH value of a liquid-phase mineral leaching system to 1.7-2.0, and preferably uses H₂SO₄And adjusting the pH value.

The method comprises the steps of leaching more than 80% of copper blue minerals with the particle size less than 74 um; the mineral leaching liquid phase system adopts a 0K culture medium.

According to the method, the concentration of the copper blue ore pulp in an ore leaching system is 10-15g/L, and preferably 10 g/L.

In the method, the sulfur oxidizing bacteria comprise: one or more of Acidithiobacillus caldus, Sulfobacillus thermosulfidooxidans and Acidithiobacillus ferrooxidans; the iron-oxidizing bacteria comprise: one or more of moderately thermophilic iron-oxidizing bacteria (Leptospirium ferriphilum), Leptospirillum ferrioxamides (Leptospirium ferrioxamides), Acidithiobacillus ferrooxidans (Acidithiobacillus ferrooxidans).

The method is to make the concentration of 10⁹Inoculating sulfur-oxidizing bacteria or iron-oxidizing bacteria solution with cell/ml or more to the ore leaching system, wherein the inoculation volume percentage is 5-10%.

In the invention, the copper blue mineral is preferably preserved in a vacuum drying oven before use by controlling the particle size of more than 80% of the copper blue mineral to be less than 74um by using a dry vibration mill. The formula of the 0K culture medium is as follows: (NH)₄)₂SO₄ 3.0g/L、KC1 0.1g/L、K₂HPO₄ 0.5g/L、MgSO₄·7H₂O 0.5g/L、Ca(NO₃)₂ 0.01g/L。

The process of the invention preferably comprises the following steps:

(1) firstly, preparing a 0K culture medium leaching liquid phase: (NH)₄)₂SO₄ 3.0g/L、KC1 0.1g/L、K₂HPO₄ 0.5g/L、MgSO₄·7H₂O 0.5g/L、Ca(NO₃)₂0.01g/L, with 0.1mol/L H₂SO₄Adjusting pH to 1.7-2.0, adding 10-20g/L Fe into the liquid phase system₂(SO₄)₃(relative molecular weight)Amount 400) sufficiently dissolved to ensure a concentration of ferric ions in the liquid phase of about 0.05-0.15M; the concentration of the pre-activated active agent is 10⁹More than cell/ml sulfur oxidizing bacteria are inoculated into an ore leaching system, the inoculation volume percentage is 5-10%, the temperature is 30-50 ℃, and the rotating speed is 170-.

(2) The concentration of ore pulp of the ore leaching copper blue is 10-15g/L, and the leaching solution in the step (1) is used for leaching the ore.

(3) Adopting atomic spectrophotometer and phenanthroline spectrophotometry and dicyclohexyl oxalyl dihydrazone spectrophotometry to treat Cu in daily leachate²⁺、Fe³⁺、Fe²⁺And monitoring the change condition of the ion concentration in real time.

(4) Added Fe³⁺(iron sulfate salt) copper blue oxide and all reduced to Fe²⁺And (6) finally. The concentration of the pre-activated active agent is 10⁹Inoculating iron-oxidizing bacteria with cell/ml or more into the ore leaching system, wherein the inoculation volume percentage is 5-10%; the temperature is 30-50 ℃, and the rotating speed is 170-.

(5) When the concentration of copper ions in the leaching solution phase fluctuates up and down in an interval of less than 5%, the final leaching stage is reached, leaching residues are collected by using medium-speed filter paper, and the surface appearance, the phase and the element composition are analyzed.

The invention has the beneficial effects that:

1. adding a leaching reagent step by step, firstly adding ferric ions and sulfur oxidizing bacteria, then adding the iron oxidizing bacteria for enhanced leaching, taking a sulfur simple substance generated in the process of converting ferric iron into ferrous iron as an energy source substance for producing the sulfur oxidizing bacteria, and adding the sulfur oxidizing bacteria and the ferric ions synchronously can obviously promote the dissolution of copper blue; ferrous iron can be used as an energy substance for the growth of iron-oxidizing bacteria, so that the iron-oxidizing bacteria can better grow, and a more remarkable ore leaching effect can be further exerted.

2.Fe³⁺The preferential addition of copper can effectively act on the copper blue surface layer and convert the copper blue surface layer into copper blue minerals with smaller particle sizes so as to increase the reaction surface area and promote the leaching process. And Fe existing in a large amount in the system²⁺By means of the surface of the copper blue mineral with excellent conductivity, Fe can be effectively realized³⁺Thereby maintaining the rate of copper blue oxidation leaching.

3. The delayed addition of the iron-oxidizing bacteria strains delays the generation time of jarosite on the mineral surface passivation layer, and provides a way for realizing the efficient utilization of copper resources in the copper blues.

Compared with the prior art, the invention has the following remarkable advantages:

1. the reaction temperature is relatively low, the operation is simple, and the ore leaching efficiency is greatly improved;

2. the concentration of the iron oxidant is required to be relatively low, and the reaction cost is reduced.

Drawings

FIG. 1(a) is a graph showing the trend of the copper leaching rate of the aseptic ceruloplasmin leaching system enhanced by iron ions according to the comparative example 1;

FIG. 1(b) is a graph showing the trend of the concentration of iron ions in the system for aseptic copper blue leaching under iron ion reinforcement in comparative example 1 with time;

FIG. 2 is a scanning electron microscope image of the surface morphology of leaching residue of the sterile ceruloplasmin leaching system under iron ion reinforcement in comparative example 1;

FIG. 3 is a substance transformation X-ray diffraction pattern of the copper blue sterile iron ion enhanced leaching process in comparative example 1;

FIG. 4 is a graph showing the time-dependent trend of copper leaching rate in a copper blue bioleaching system enhanced by ferrous ions in comparative example 2, wherein 318K-Fe²⁺As a control group with a bacterial system;

FIG. 5 is a scanning electron microscope image of the surface morphology of leached slag of a copper blue bioleaching system under the strengthening of ferrous ions in comparative example 2;

FIG. 6 is a graph showing the time-dependent trend of the copper leaching rate in a copper blue bioleaching system enhanced by ferric ions in comparative example 3;

FIG. 7 is a graph showing the time-dependent change trend of the copper leaching rate in a copper blue bioleaching system enhanced by sulfur oxidizing bacteria in comparative example 4;

FIG. 8 is a graph showing the time-dependent change of the leaching rate of copper in the process of the comparative example 5 in which ferric ions (0.1M) are added step by step and the mixed leaching bacteria are used for enhanced leaching of copper blue;

FIG. 9 is a graph showing the time-dependent trend of copper leaching rate in the ceruloplasmin bioleaching system enhanced by ferric ions (0.1M) in example 1;

fig. 10 is a graph showing the time-dependent trend of copper leaching rate in the ceruloplasmin bioleaching system enhanced by ferric ions (0.07M) in example 2.

Detailed Description

The following specific examples or embodiments are intended to further illustrate the invention, but are not intended to limit the invention.

Table 1 relevant parameter settings for each experimental group in comparative examples 1 and 2

Comparative example 1:

the process of this comparative example was carried out essentially as follows

(1) Crushing a copper blue pure ore mineral sample, sieving until the particle size of more than 80 percent of the mineral is below 74um, storing in a vacuum drying oven for later use, and detecting the phase components by adopting a synchronous radiation SR-XRD method before the experiment, wherein the phase components only contain a copper blue phase (File ID: PDF # 78-2391). XRF elemental analysis shows that the sample has the mineral element composition of Cu 61.78%, S33.71%, Fe 0.0198%, O4.35%, Si 0.031 and Cl 0.11%, and the content of other impurity elements is relatively low. Therefore, it can be considered that the mineral has a higher purity.

(2) An aseptic copper blue leaching experiment is designed, and the promotion effect of exogenous ferric ions and ferrous ions on copper blue leaching under the conditions of low temperature (30-303K) and medium-high temperature (45-318K) is respectively explored.

(3)318K-Fe³⁺And 303K-Fe³⁺In the experimental group, the leaching solution is a 0K culture medium formula: (NH)₄)₂SO₄ 3.0g/L、KC1 0.1g/L、K₂HPO₄ 0.5g/L、MgSO₄·7H₂O 0.5g/L、Ca(NO₃)₂0.01 g/L; controlling pH value within 1.7-2.0 range by dilute sulphuric acid solution, and fully dissolving 2g Fe per 100ml leachate₂(SO₄)₃(relative molecular mass 400); 318K-Fe²⁺And 303K-Fe²⁺In the experimental group, 2.78g of FeSO was sufficiently dissolved in 100ml of the leaching solution₄·7H₂O (relative molecular mass 278); the 318K-Non and 303K-Non experimental groups are control groups without adding exogenous iron ions, and the setting parameters of the experimental groups are shown in the table 1. The rotating speed of the shaking table is set to be 170-200 r/min.

(4) Adding the ceruloplasmin sample prepared in the step (1) into the 6 groups of experiments in the step (3), wherein the set ore pulp concentration is 10 g/L; the ion concentration in the leachate was measured by atomic spectrophotometer, phenanthroline spectrophotometry, and bicyclohexanoneoxalyl dihydrazone spectrophotometry, and the results are shown in fig. 1.

(5)318K-Fe³⁺In the leaching process, the increase speed of the copper ion leaching rate is reduced after 4d, and a leaching sample of a time node is selected for slag sample analysis. Likewise, for 318K-Fe²⁺And (3) carrying out slag sample analysis on a leaching sample leached at the same time, filtering leaching slag at the time node, analyzing the surface morphology of the leaching slag by using SEM (scanning Electron microscope), analyzing the phase composition of the leaching slag by XRD (X-ray diffraction), and revealing the action mechanism of the exogenous iron, wherein the results are shown in figures 2 and 3.

And (4) conclusion: as shown in figure 1, the dissolution of copper in the copper blue is remarkably promoted by adding exogenous iron ions, and Fe³⁺The effect is better than that of Fe in the early reaction stage²⁺(ii) a When the reaction temperature was increased from 303K to 318K, the effect of the exogenous iron on promoting the dissolution of copper blue was further enhanced, and the degree of surface corrosion was further enhanced (fig. 2(c, d), fig. 2(e, f)). Both XRD and SEM results show that the surface of the copper blue only generates a new phase of elemental sulfur during the aseptic leaching process (figure 3; figure 2(c, d)), but Fe³⁺The ceruloplasmin minerals can be converted into ceruloplasmin-like substances with smaller particle size and larger surface area by directly reacting with the surface of the ceruloplasmin, so that the dissolving of the ceruloplasmin at the early stage is accelerated (fig. 2 (a)); and Fe²⁺Copper blue dissolution can also be promoted, but Fe²⁺Needs to be converted into Fe on the surface of the copper blue by oxygen³⁺Further, the surface of the copper blue was corroded (FIG. 2(b)), and the elemental sulfur generated in the reaction was attached to the surface of the copper blue, as opposed to Fe³⁺System due to Fe²⁺The dissolving rate of the copper blue in the system is more limited by the diffusion of surface sulfur, and the reaction efficiency is reduced to a certain degree.

Comparative example 2:

(1) a bacterial ceruloplasmin leaching experiment is designed, and the synergistic effect of exogenous ferrous ions and moderate thermophilic bacteria on ceruloplasmin leaching under the condition of medium temperature (45-318K) is respectively explored.

(2) In the experimental groups of 318K-Bio1 and 318K-Bio2, the leaching solution adopts a 0K culture medium formula: (NH)₄)₂SO₄ 3.0g/L、KC1 0.1g/L、K₂HPO₄ 0.5g/L、MgSO₄·7H₂O 0.5g/L、Ca(NO₃)₂0.01 g/L; the pH value is controlled within the range of 1.7-2.0 by using a dilute sulfuric acid solution. 2.78g of FeSO is fully dissolved in each 100ml of leaching solution₄·7H₂Inoculating activated iron-oxidizing bacteria Leptospirillum ferriphilum in O, 318K-Bio1, inoculating mixed mineral leaching bacteria in 318K-Bio2, wherein the mixed mineral leaching bacteria is obtained by uniformly mixing medium thermophilic sulfur-oxidizing bacteria (Acidithiobacillus caldus) and medium thermophilic iron-oxidizing bacteria (Leptospirillum ferriphilum) according to the mass percentage of 1:1, and inoculating 10ml of leachate with the concentration of 10ml per 100ml⁹cell/ml of the bacterial solution. Experimental group setup parameters are shown in table 1. Both groups had the bacterial inoculation time at day 1 of the start of the reaction. The rotating speed of the shaking table is set to be 170-200 r/min.

(3) Adding the ceruloplasmin sample prepared in the comparative example 1(1) into the 2 experiments in the comparative example 2, wherein the concentration of the ore pulp is 10 g/L; the ion concentration in the leachate was measured by atomic spectrophotometer, phenanthroline spectrophotometry, and bicyclohexanoneoxalyl dihydrazone spectrophotometry, and the results are shown in fig. 4.

(4) Filtering the leaching residue during leaching, and analyzing the surface composition

And (4) conclusion: FIG. 1318K-Fe³⁺FIG. 4318K-

Bio

1, 318K-Fe²⁺The time-dependent change of the leaching rate of the medium copper can be seen, the dissolving rates of the copper blue are similar in the stage of 6 days before leaching, which indicates that the iron oxidizing bacteria oxidize Fe²⁺Is Fe³⁺Is the main factor affecting the leaching in the first 6 days. After 6 days, the growth rate of the iron-oxidizing bacteria bioleaching system 318K-Bio1 is slowed down, and SEM surface morphology and XRD analysis show that flaky sulfur and jarosite are covered on the surface of the copper blue (figure 5(a, b)), and the formation of the substances hinders the copper blue leaching. However, for 318K-Bio2, the copper blue extraction rate remained increased after 6 days of leaching, thatBecause the existence of sulfur oxidizing bacteria in the system eliminates partial elemental sulfur generated by the dissolution of the surface of the copper blue, the copper blue is continuously dissolved at the moment. However, the existence of sulfur oxidizing bacteria and iron oxidizing bacteria has both favorable leaching promoting effect and disadvantages, namely sulfate ions (SO) generated by the sulfur oxidizing bacteria₄ ^2-) Fe produced by oxidation with iron-oxidizing bacteria³⁺Under the high potential condition in the later stage of leaching, compact jarosite is easily generated, thereby passivating the surface of the copper blue (fig. 5(c, d)).

Comparative example 3:

(1) a bacterial copper blue leaching experiment is designed, and the synergistic effect of exogenous ferric ions and mixed leaching strains on copper blue leaching under the condition of medium temperature (45-318K) is respectively explored.

(2) In the shaking-flask leaching experiment, the leaching solution adopts a formula of a 0K culture medium: (NH)₄)₂SO₄ 3.0g/L、KC1 0.1g/L、K₂HPO₄ 0.5g/L、MgSO₄·7H₂O 0.5g/L、Ca(NO₃)₂0.01 g/L; the pH value is controlled within the range of 1.7-2.0 by using a dilute sulfuric acid solution. 2g Fe is fully dissolved in each 100ml leaching solution₂(SO₄)₃The inoculated mixed leaching-ore bacteria is obtained by uniformly mixing medium thermophilic sulfur-oxidizing bacteria (Acidithiobacillus caldus) and medium thermophilic iron-oxidizing bacteria (Leptospirillum ferriphilum) according to the mass percentage of 1:1, and 10ml of 10-concentration 10 is inoculated to every 100ml of leaching solution⁹cell/ml bacterial solution. The time of bacterial inoculation was day 1 from the start of the reaction. The rotating speed of the shaking table is set to be 170-200 r/min.

(3) Adding the ceruloplasmin sample prepared in the comparative example 1(1) into the experiment in the comparative example 3, wherein the concentration of the ore pulp is 10 g/L; the ion concentration in the leachate was measured by atomic spectrophotometer, phenanthroline spectrophotometry, and bicyclohexanoneoxalyl dihydrazone spectrophotometry, and the results are shown in fig. 6.

And (4) conclusion: analysis of 318K-Bio2 (Fe) in FIG. 6 and comparative example 2²⁺Mixed species leaching system) change of leaching rate of copper ions with time, and the results show that the mixed species copper blue leaching system is despite of exogenous Fe³⁺The addition of (A) can obviously improve the dissolution reaction rate of the copper blue in the early stage, but two of the reaction ratesThe system can finally reach the leaching rate of 76 percent of copper ions after 12 days of reaction. In the sulfuric acid system, due to Fe³⁺The copper oxide blue is completely converted into Fe in the early stage of the reaction²⁺Therefore, the replacement of the exogenous ferrous salt with the ferric salt does not substantially help to improve the efficiency of the ceruloplasmin mixed strain leaching system.

Comparative example 4:

(1) a bacterial copper blue leaching experiment is designed, and the effect of exogenous ferric ions and sulfur oxidizing bacteria (Acidithiobacillus caldus) on copper blue leaching under the condition of medium temperature (45-318K) is respectively explored.

(2) In the shaking-flask leaching experiment, the leaching solution adopts a formula of a 0K culture medium: (NH)₄)₂SO₄ 3.0g/L、KC1 0.1g/L、K₂HPO₄ 0.5g/L、MgSO₄·7H₂O 0.5g/L、Ca(NO₃)₂0.01 g/L; the pH value is controlled within the range of 1.7-2.0 by using a dilute sulfuric acid solution. Dissolving 1g of sulfur powder in 100ml of leachate, inoculating ore leaching bacteria to obtain medium thermophilic sulfur oxidizing bacteria (Acidithiobacillus caldus), and inoculating 10ml of leachate with concentration of 10⁹cell/ml of the bacterial solution. The time of bacterial inoculation was day 1 from the start of the reaction. The rotating speed of the shaking table is set to be 170-200 r/min.

(3) Adding the ceruloplasmin sample prepared in the comparative example 1(1) into the experiment in the comparative example 4, wherein the concentration of the ore pulp is 10 g/L; the ion concentration in the leachate was measured by atomic spectrophotometer, phenanthroline spectrophotometry, and bicyclohexanoneoxalyl dihydrazone spectrophotometry, and the results are shown in fig. 7.

And (4) conclusion: as can be seen from the biological leaching result of the copper blue under the independent action of the sulfur oxidizing bacteria, the leaching rate of copper ions only reaches 13 percent after 18 days of leaching. At the moment, no exogenous iron ions are added, and the sulfur oxidizing bacteria cannot effectively improve the dissolving rate of the copper blue due to the fact that a system is lack of necessary oxidizing agents.

Comparative example 5:

(1) a bacterial copper blue leaching experiment is designed, and the process of adding ferric iron and mixed mineral leaching bacteria step by step to strengthen leaching of copper blue under the condition of medium temperature (45-318K) is explored.

(2) In the shaking-flask leaching experiment, the leaching solution adopts a formula of a 0K culture medium: (NH)₄)₂SO₄ 3.0g/L、KC1 0.1g/L、K₂HPO₄ 0.5g/L、MgSO₄·7H₂O 0.5g/L、Ca(NO₃)₂0.01 g/L; the pH value is controlled within the range of 1.7-2.0 by using a dilute sulfuric acid solution. 2g Fe is fully dissolved in each 100ml leaching solution₂(SO₄)₃The leaching rate of liquid phase copper ions is 38 percent after 5 days from the beginning of the reaction, the inoculated mixed leaching-ore bacteria is obtained by evenly mixing medium thermophilic sulfur-oxidizing bacteria (Acidithiobacillus caldus) and medium thermophilic iron-oxidizing bacteria (Leptospirillum ferriphilum) according to the mass percentage of 1:1, and 10ml of leaching solution with the concentration of 10 is inoculated to 100ml of leaching solution⁹cell/ml of the bacterial solution. The rotating speed of the shaking table is set to be 170-200 r/min.

(3) Adding the ceruloplasmin sample prepared in the comparative example 1(1) into the experiment in the comparative example 5, wherein the concentration of the ore pulp is 10 g/L; the ion concentration in the leachate was measured by atomic spectrophotometer, phenanthroline spectrophotometry, and bicyclohexanoneoxalyl dihydrazone spectrophotometry, and the results are shown in fig. 8.

And (4) conclusion: from the graph of the change of the leaching rate of copper ions with time shown in FIG. 8, 4 days before the reaction, in terms of Fe³⁺The copper blue mineral can be dissolved quickly, but the copper leaching rate is increased slowly after 5 days of reaction, and after the mixed leaching bacteria are inoculated and activated, although a large amount of reduced Fe exists in the solution²⁺The growth of the iron-oxidizing bacteria can be effectively promoted, but the bacteria still need a certain time to grow, and under the experimental condition, the Fe of the iron-oxidizing bacteria after 5 days of reaction²⁺The system becomes a dominant strain and can inhibit the activity of sulfur oxidizing bacteria to a certain degree. As can be seen from fig. 8, the leaching rate of copper ions can be rapidly increased in 7-12 days when the mixed leaching bacteria are added, but after 12 days, the leaching rate of copper ions reaches an equilibrium value of 71%, which is slightly lower than the final leaching rate of 17 days when the copper ions in comparative examples 2 and 3 react, which indicates that the copper blue dissolution efficiency cannot be further improved by adding the mixed leaching bacteria in a delayed manner after the external ferric iron is added.

Example 1:

(1) a bacterial copper blue leaching experiment is designed, and the process of adding ferric iron (with the ion concentration of 0.1M) and sulfur oxidizing bacteria for reaction and then adding iron oxidizing bacteria for strengthening leaching of copper blue is explored under the condition of medium temperature (45-318K).

(2) In the shaking-flask leaching experiment, the leaching solution adopts a formula of a 0K culture medium: (NH)₄)₂SO₄ 3.0g/L、KC1 0.1g/L、K₂HPO₄ 0.5g/L、MgSO₄·7H₂O 0.5g/L、Ca(NO₃)₂0.01 g/L; the pH value is controlled within the range of 1.7-2.0 by using a dilute sulfuric acid solution. 2g Fe is fully dissolved in each 100ml leaching solution₂(SO₄)₃On the 1 st day after the start of the reaction, medium thermophilic sulfur oxidizing bacteria (Acidithiobacillus caldus) were inoculated, and 5ml of 10-concentration leachate was inoculated per 100ml of the leachate⁹cell/ml bacterial liquid, reacting for 3-5 days, converting ferric iron into ferrous iron, adding iron oxidizing bacteria, leaching copper ion in the leaching solution to 35-40%, inoculating medium thermophilic iron oxidizing bacteria (Leptospirillum ferriphilum) into the leaching system, inoculating 5ml leaching solution with 10 concentration per 100ml⁹cell/ml of the bacterial solution. The rotating speed of the shaking table is set to be 170-200 r/min.

(3) Adding the ceruloplasmin sample prepared in the comparative example 1(1) into the experiment in the example 1, wherein the concentration of the ore pulp is 10 g/L; the ion concentration in the leachate was measured by atomic spectrophotometer, phenanthroline spectrophotometry, and bicyclohexanoneoxalyl dihydrazone spectrophotometry, and the results are shown in fig. 9.

And (4) conclusion: FIG. 9 shows that the leaching rate of copper ions in the system is as high as 92% after the reaction for 9 days, so that the invention is proved to be capable of effectively improving the extraction rate of copper blue and copper and simultaneously reducing the time required by the reaction.

Example 2:

(1) a bacterial copper blue leaching experiment is designed, and the process of adding ferric iron (with the ion concentration of 0.07M) and sulfur oxidizing bacteria for reaction and then adding iron oxidizing bacteria for strengthening leaching of copper blue is explored under the condition of medium temperature (45-318K).

(2) In the shaking-flask leaching experiment, the leaching solution adopts a formula of a 0K culture medium: (NH)₄)₂SO₄ 3.0g/L、KC1 0.1g/L、K₂HPO₄ 0.5g/L、MgSO₄·7H₂O 0.5g/L、Ca(NO₃)₂0.01 g/L; the pH value is controlled within the range of 1.7-2.0 by using a dilute sulfuric acid solution. Each 100ml of the leaching solution is fully dissolved with 1.4g of Fe₂(SO₄)₃On the 1 st day after the start of the reaction, medium thermophilic sulfur oxidizing bacteria (Acidithiobacillus caldus) were inoculated, and 5ml of 10-concentration leachate was inoculated per 100ml of the leachate⁹cell/ml bacterial liquid, reacting for 3-5 days, converting ferric iron into ferrous iron, adding iron oxidizing bacteria, leaching copper ion in the leaching solution to 35-40%, inoculating medium thermophilic iron oxidizing bacteria (Leptospirillum ferriphilum) into the leaching system, inoculating 5ml leaching solution with 10 concentration per 100ml⁹cell/ml of the bacterial solution. The rotating speed of the shaking table is set to be 170-200 r/min.

(3) Adding the ceruloplasmin sample prepared in the comparative example 1(1) into the experiment in the example 2, wherein the concentration of the ore pulp is 10 g/L; the ion concentration in the leachate was measured by atomic spectrophotometer, phenanthroline spectrophotometry, and bicyclohexanoneoxalyl dihydrazone spectrophotometry, and the results are shown in fig. 10.

And (4) conclusion: FIG. 10 shows that the reaction rate in this system was lower than that in example 1 as a whole, and that the leaching rate of copper ions reached 86% after 17 days of reaction, and that the leaching rate of copper ions tended to increase further with time. Indicating that the concentration of iron ions has difference on the copper blue leaching process within a certain concentration range, and preferably 0.1M Fe³⁺And (4) concentration.

Example 3:

for the ceruloplasmin leaching experiment under the low temperature (30-303K), compared with the experiment 1, the temperature is different only, after the ferric iron (with the ion concentration of 0.1M) and the sulfur oxidizing bacteria are added for reaction, the process of the reinforced leaching of the ceruloplasmin by adding the iron oxidizing bacteria is added, in the comparative example 1, under the low temperature (30-303K) reaction condition, 303K-Fe³⁺Solution Fe in the experimental group³⁺The ion concentration decreased linearly within 12 days of reaction, while Fe²⁺The concentration increases linearly (FIG. 1(b)), the copper blue dissolution reaction is slower than at moderate temperatures (45 ℃ to 318K). Thus, the low temperature (30-303K) reaction takes longer to reach the end of leaching than the medium temperature (45-318K) reaction of example 1, so the conditions of example 1 are preferably applied to copperBlue bioleaching process.

Claims

1. A method for strengthening biological leaching of copper blue by comprehensively utilizing ferric ions and ferrous ions is characterized by sequentially comprising the following steps of:

(1) leaching copper blue by adopting ferric sulfate and adding sulfur oxidizing bacteria as a leaching agent;

(2) adding iron-oxidizing bacteria into the leaching system in the step (1) for leaching;

after all ferric ions in the step (1) are converted into ferrous ions, adding iron oxidizing bacteria; step (2), completing leaching when the concentration of copper ions in the leaching solution phase fluctuates within an interval of less than 5%;

the sulfur oxidizing bacteria comprise: one or two of Acidithiobacillus caldus and Acidithiobacillus caldus; the iron-oxidizing bacteria comprise: one or two of moderate thermophilic iron oxidizing bacteria and ferrous oxide leptospirillum.

2. The method of claim 1,

step (1) leaching Fe in the system³⁺The concentration of (A) is 0.05-0.15M.

3. The method of claim 2,

step (1) leaching Fe in the system³⁺The concentration of (A) is 0.07-0.12M.

4. The method of claim 3,

step (1) leaching Fe in the system³⁺The concentration of (3) is 0.1M.

5. The method of claim 1,

the leaching reaction temperature is controlled at 30-50 ℃.

6. The method of claim 5,

the leaching reaction temperature is controlled at 42-47 ℃.

7. The method of claim 6,

the leaching reaction temperature is controlled at 45 ℃.

8. The method of claim 1 or 5 or 6 or 7,

the leaching reaction speed is 170-200 r/min.

9. A method according to claim 1 or 5 or 6 or 7, characterized in that the pH of the liquid phase leaching system is adjusted to 1.7-2.0.

10. The method of claim 9, wherein H is used₂SO₄And adjusting the pH value.

11. The method according to claim 1 or 5 or 6 or 7, characterized in that more than 80% of the ceruloplasmin minerals with a size less than 74 μm are leached; A0K culture medium is adopted as a liquid-phase ore leaching system.

12. The method according to claim 1, characterized in that the pulp concentration of the copper blue in the leaching system is 10-15 g/L.

13. The method according to claim 12, characterized in that the pulp concentration of the copper blue in the leaching system is 10 g/L.

14. The method according to claim 1, wherein the concentrations are 10 in each case⁹Inoculating sulfur-oxidizing bacteria or iron-oxidizing bacteria solution with cell/ml or more to the ore leaching system, wherein the inoculation volume percentage is 5-10%.