Method for mineral flotation by using biological reagent extracted from gram-positive bacteria
阅读说明：本技术 采用从革兰氏阳性菌中提取的生物试剂进行矿物浮选的方法 (Method for mineral flotation by using biological reagent extracted from gram-positive bacteria ) 是由 M·L·特雷姆 J·G·S·普埃列斯 A·G·梅尔马 C·A·C·奥利韦拉 L·M·多罗萨里 于 2018-05-16 设计创作，主要内容包括：本发明涉及一种采用革兰氏阳性菌混浊红球菌和红平红球菌提取物作为生物反应试剂的矿物浮选方法。就此而言,通过采用革兰氏阳性菌作为生物反应试剂来体现矿物的可浮性,以表现其作为合成反应试剂的替代物以及单独采用微生物(生物质)的替代物的未来前景。(The invention relates to a mineral flotation method using gram-positive bacteria rhodococcus turbidity and rhodococcus erythropolis extracts as biological reaction reagents. In this regard, the floatability of minerals is embodied by the use of gram-positive bacteria as bioreactive agents to show its future promise as a substitute for synthetic reactive agents as well as for microorganisms (biomass) alone.)
1. A mineral flotation method is characterized in that a biological reaction reagent extracted from rhodococcus (rhodococcus turbidity, rhodococcus erythropolis) is adopted, and the method comprises the following steps:
a-cultivating bacteria
B-extraction of biological reagents
C, ore crushing and slurry preparation;
d-addition and modulation of biological agents;
e-flotation.
2. A mineral flotation process according to claim 1, wherein the minerals include hematite, calcite, dolomite and apatite for the purpose of recovering the specified metals/elements from ores containing any of the foregoing minerals.
3. Mineral flotation method according to claim 1, characterized in that the mineral comprises a mineral system, preferably a hematite-quartz system.
4. Mineral flotation process according to claim 1, characterized in that the extraction of bioreaction reagents from bacteria of the genus Rhodococcus (Rhodococcus clouded, Rhodococcus erythropolis) is carried out by a solvent extraction process, preferably hot ethanol (100-.
5. A mineral flotation process according to claim 4, wherein the reactive reagent is a biological reactive reagent extracted and purified from Rhodococcus (Rhodococcus clouded, Rhodococcus erythropolis).
6. A mineral flotation process according to claim 1, wherein the reagents added in step D comprise only bioreactive reagents extracted from rhodococcus (rhodococcus rhodochrous, rhodococcus erythropolis) in a concentration range of 5 to 200 mg/l.
7. A mineral flotation process according to claim 1, wherein the reagents added in step D include bioresponse reagents extracted from rhodococcus (rhodococcus rhodochrous), depressants, collector reagents and frothers.
8. Mineral flotation process according to claim 1, characterized in that the adjustment of step D is carried out in a pH range of 3 to 7 for the hematite-quartz system.
9. A mineral flotation process according to claim 1, characterized in that the flotation of step E can be carried out in a Hallimond tube, a flotation cell or a flotation column.
10. Mineral flotation process according to claim 1, characterized in that the flotation of step E is preferably direct flotation of the specified metals/elements.
11. A mineral flotation process according to claim 1, characterized in that the flotation of step E is carried out in the pH range of 3 to 7 for the hematite-quartz system.
Technical Field
The invention is mainly used in the mining industry and comprises a method for performing mineral flotation by using a biological reaction reagent extracted from gram-positive bacteria (rhodococcus turbinatus and rhodococcus erythropolis).
Background
One of the major mineral beneficiation processes employed in the mining industry is flotation. Bioflocculation is defined as a separation process in which a given mineral type is selectively floated or suppressed using a biologically derived reagent, i.e., a bioreactive reagent.
In recent years, bioflocculation has been extensively studied as an attractive alternative to traditional reagents with green reagents. The biological reaction reagent has the characteristics of low toxicity, easy degradation after being discarded, low production raw material cost, reproducibility and easy acquisition. In addition, the bioreaction reagent can be used for processing low-grade ores and tailings, thereby being applied to ore deposits with low commercial grade.
On the other hand, although there is evidence that bioflocculation is a reaction process with good recovery and selectivity, there are several factors that have hampered the development of this technology, including minor technological advances, and little is known about the reaction mechanism, reaction kinetics, and reaction thermodynamics of this process.
Bioreactive agents are heterogeneous mixtures of various compounds that are difficult to characterize and therefore difficult to understand the specific reaction mechanism in a flotation process where they can selectively alter the characterization of a target mineral. Furthermore, it is noted that theoretical models for embodying mineral/bacterial adhesion behavior have not been incorporated into biological factors. These factors are included and are crucial for a thorough understanding of the bioflocculation process.
The use of microorganisms and/or their metabolites as reactive agents, in particular capture agents, foaming agents and modified mineral processing operations, has become very attractive because of its great technical potential, environmental acceptability and selectivity in mineral particle processing. These microorganisms and/or their metabolites may directly or indirectly alter the characterization of the mineral. The direct reaction mechanism involves direct adhesion of the microbial cells to the mineral particles, while the indirect reaction mechanism involves product metabolism or soluble cellular constituents as surface active agents. Both interactions lead to a change in chemical characterization, making it hydrophilic or hydrophobic, which is determined by the characteristics of the bacteria and minerals.
The main function of microorganisms and/or their metabolites as bioreactive agents in mineral processing is related to the presence of supporting functional groups (hydrocarbon chains) and polar groups (carboxyl, phosphate, hydroxyl) on their cell surface or in the cell. Microbial production of internal and/or external compounds that can alter the interfacial properties and thus the amphiphilic molecular characteristics of mineral surfaces.
Rhodococcus erythropolis and Rhodococcus turbinatus bacteria are gram-positive, nonpathogenic, widely occurring in nature and widely available.
For example CN102489415 describes the use of rhodococcus erythropolis as a capture agent in the flotation process of hematite containing systems. This document differs from the present invention in that it employs the bacteria themselves (biomass) as a capture agent rather than a bioreactive agent extracted from the bacteria.
CN102911904 describes the use of bacteria as a capture agent in the flotation of ores containing refractory hematite. This document differs from the present invention, as in CN102489415, in that it employs the bacteria themselves (biomass) as their capture agent, rather than the bioreactive agent extracted from the bacteria.
In the article "production of biosurfactant of rhodococcus erythropolis and its use in degreasing", published by the federal university of ricoxi, at 29/10/2010, a biosurfactant extracted from rhodococcus erythropolis used in the treatment of petroleum contaminated soils is mentioned. The present invention differs from said document in that it is mineral flotation, not oil contaminated soil treatment.
An article "influence of rhodococcus erythropolis on flocculation and flotation of pure minerals in hematite" published by the university of beijing science and technology, 2013, 2.27 describes the use of rhodococcus erythropolis bacteria as a capture agent in the flotation process of hematite-containing systems. This document differs from the present invention in that it employs bacteria (biomass) as its capture agent, rather than bioreactive agents extracted from bacteria, as in CN102489415 and CN 102911904.
A publication published by Polish Frouwa university of Walsh, 5/6/2012, "flotation of serpentine and quartz using biosurfactant" proposes a biosurfactant extracted from Bacillus circulans and Streptomyces species for use in flotation of quartz and serpentine. The present invention differs from said document in that they are different bacteria and different minerals to float.
As will be described in further detail below, the present invention provides a method for mineral flotation using bioreactive agents extracted from the bacteria Rhodococcus turbinatus and Rhodococcus erythropolis.
Disclosure of Invention
The main object of the present invention is to provide a method for mineral flotation using bioreactive agents extracted from bacteria of the genera rhodococcus clouding and rhodococcus erythropolis.
Therefore, the process of extracting metabolites, particularly protein compounds, from Rhodococcus rhodochrous and Rhodococcus erythropolis was evaluated in order to use them as collecting bioresponse agents in mineral flotation, since proteins tend to provide hydrophobicity at the mineral surface, thus facilitating the flotation process.
In this regard, the floatability of minerals was assessed using bioresponse reagents extracted from Rhodococcus to determine their potential as alternatives to synthetic reagents and to microorganisms (biomass) alone.
Drawings
The detailed description given below refers to the accompanying drawings and their respective reference numerals.
FIG. 1 illustrates a process flow diagram for extracting bioreactive agents from microorganisms;
FIG. 2 shows the infrared spectra of a bacterium of the genus Rhodococcus turbulently (blue line) and a crude bioreaction reagent (black line);
FIG. 3 shows the IR spectra of Rhodococcus erythropolis (blue line) and crude bioreaction reagent (black line);
FIG. 4 shows the effect of bioreactive reagent concentration on the surface tension of deionized water at neutral pH at 20 ℃: the solid line indicates the biological activity extracted from Rhodococcus turbinatus and the solid line indicates the biological activity extracted from Rhodococcus erythropolis;
FIG. 5 shows a bar graph comparing hematite floatability using bacteria (biomass) and bioreactive reagents: (a) pH3, (b) pH5, (c) pH7, (d) pH9, (e)
FIG. 6 is a graph illustrating the floatability of hematite in bioresponse agents of different concentrations extracted from Rhodococcus turbinatus;
FIG. 7 is a graph illustrating the floatability of hematite in bioresponse agents of varying concentrations extracted from Rhodococcus erythropolis;
FIG. 8 shows a bar graph comparing the floatability of hematite, quartz, dolomite, calcite and apatite using bioreactive agents extracted from Rhodococcus hazeus: (a) pH3, (b) pH5, (c) pH7, (d) pH9, (e)
FIG. 9 shows a bar graph comparing the floatability of hematite, quartz, dolomite, calcite and apatite using bioreactive agents extracted from Rhodococcus erythropolis: (a) pH3, (b) pH5, (c) pH7, (d) pH9, (e)
Detailed Description
It is emphasized that the following description will begin with a preferred embodiment of the invention. It will be obvious to those skilled in the art, however, that the invention is not limited to this particular embodiment.
The invention relates to a method for floating biological reaction reagents extracted from bacteria rhodococcus turbinatus and rhodococcus erythropolis, which comprises the following steps: i) cultivating bacteria; ii) extracting the biological agent; iii) ore comminution and pulping; iv) adding and adjusting biological agents; v) flotation.
As is well known to the person skilled in the art, the growth broth used in the present invention for inoculating bacteria should preferably comprise a source of nutrients, proteins and carbohydrates. The broth may be prepared using commercial reagents or may be partially or completely replaced with ingredients from other production chains, such as food industry residues. Growth of the microorganisms may be carried out in a rotary kiln or, for large scale processes, fermenters or bioreactive reagents may be employed. First the temperature and the presence of contaminants are controlled.
According to the present invention, the extraction of bioreaction reagents from Rhodococcus bacteria (Rhodococcus turbinatus, Rhodococcus erythropolis) is carried out by a solvent extraction process, preferably hot ethanol extraction (100 ℃ C.) at 140 ℃.
FIG. 1 shows a process flow diagram for extracting bioreaction reagents from microorganisms, comprising the steps of (i) solid/liquid separation and water washing; (ii) resuspending with ethanol; (iii) sterilizing under high pressure; (iv) a new solid/liquid separation; (v) drying or lyophilizing the biomass; (vi) (vii) resuspending with water (vii) for new solid/liquid separation.
The solid/liquid separation step may preferably be carried out by centrifugation or filtration using 25 μm open pore membranes. Autoclaving should preferably be carried out at a pressure of 0.5 to 1.5 bar and a temperature in the range from 100 to 140 ℃
The ratio of ethanol and water used in the extraction and dissolution of the soluble fraction, respectively, can be adjusted according to the growth process of the microorganism. Factors that may cause process variations: broth ingredients (which may be replaced, for example, by food industry tailings), equipment, and growth conditions (e.g., inoculation with biofermentation agents, immobilized cells).
According to the invention, the extraction of the bioreaction reagent from bacteria of the genus Rhodococcus (Rhodococcus turbinatus, Rhodococcus erythropolis) may comprise a purification step.
The resulting bioreaction reagent is preferably stored at 4 ℃ for a maximum of 5 days for later use in the flotation process. The extraction method employed allows the recovery of components related to intracellular compounds and compounds present in the cell wall of the microorganism. These substances are responsible for rendering the mineral surface hydrophobic.
The bioreactive agent extracted from gram-positive bacteria belonging to the genus Rhodococcus (Rhodococcus turbinatus, Rhodococcus erythropolis) of the present invention can be used for the flotation of any iron mineral, preferably hematite. It is also possible to float mineral systems, preferably hematite-quartz systems. However, it is also possible to flotate ores containing other minerals of interest, such as calcite, dolomite and apatite, using the process of the present invention.
According to the present invention, the reagent added in the flotation step may contain only the bioreactive agent extracted from Rhodococcus bacteria (Rhodococcus turbinatus, Rhodococcus erythropolis) at a concentration ranging from 5 to 200 mg/L, or may be used in combination with any of the following reagents, which are an inhibitor, a capturing agent and a foaming agent.
According to the present invention, the adjusting step may be performed at a pH value in the range of 3 to 7 for hematite-quartz systems.
Still according to the invention, the flotation step may be carried out in a Hallimond tube, a flotation cell or a flotation column.
According to the invention, the flotation step preferably consists of direct flotation of the metal/element of interest.
Still according to the invention, the flotation step of the hematite-quartz system may be performed at a pH value in the range of 3 to 7.
As shown in examples 4, 5 and 6, the results of the bioreactive reagent flotation test according to the present invention show the potential use of bioreactive reagents as a replacement for synthetic reagents in mineral flotation processes. For example, in addition to accelerating the flotation process, the use of bioreactive reagents also increases the recovery of hematite. FIG. 5 shows the composition of a bar graph comparing the floatability of hematite using Rhodococcus clouding and its bioreactive agents at different pH values: (a) pH3, (b) pH5, (c) pH7, (d) pH9, (e)
The maximum floatability of hematite obtained with bacteria (biomass) at neutral pH was 43% (fig. 5(c)), while the maximum recovery with bioreactive reagents at acidic pH was 95% (fig. 5(a) and (b)). Even in an acidic environment, the high performance of bioreactive agents is characteristic of most bioreactive agents, which exhibit stability even under extreme temperature, pH and salinity conditions. The results show that the bioresponse agent according to the invention has a high affinity for hematite particles and that the agent consumption is relatively low compared to the use of bacteria (biomass).
Example 1
Bioreaction extraction tests were performed from microorganisms. Rhodococcus bacteria (Rhodococcus turbinatus, Rhodococcus erythropolis) were purchased from the Pasteur environment and the Collection of Industrial microorganisms (Brazilian environment and Collection of Industrial microorganisms-UNICAMP).
The culture solution for the growth of rhodococcus turbinatus is composed of 10g dm-3Glucose, 5g dm-3Peptone, 3g dm-3Malt extract, 3g dm-3Yeast extract, and 2g dm-3CaCO3And (4) forming. The culture solution for Rhodococcus erythropolis is composed of 17g dm-3Casein extract, 3g dm-3Soybean powder, 5g dm-3Sodium chloride, 2.5g dm-3Glucose and 2.5gdm-3Dipotassium phosphate. The bacteria were incubated in a rotary oven at 125 rpm for 7 days.
After the growth period, biomass from the growth broth (cell suspension) was separated by centrifugation at 4000 rpm (fig. 1). The biomass was washed with deionized water and centrifuged again to remove the remaining growth broth. The washing was repeated twice.
The biomass was resuspended in 500 ml of ethanol per liter of cell suspension used for the initial centrifugation process. For bioreaction reagent extraction, the solution containing biomass and ethanol was autoclaved at 1 bar, 121 ℃ for 20 minutes.
After extraction, a new centrifugation step is performed to separate the biomass from the extract. The supernatant was discarded and the biomass was oven dried at 50 ℃ for 24 hours.
The already dried biomass was resuspended in deionized water at a rate of 125 ml of water per liter of growth broth (cell suspension used in the extraction process). The mixture was centrifuged and the water insoluble fraction was discarded while the soluble fraction was stored at 4 ℃ for up to 5 days for microbial culture and characterization analysis.
Example 2
In order to identify the functional groups present in the bioreactive reagent obtained in example 1, infrared analysis was performed using a Nikeley Fourier
In order to compare the characteristics of the bioreaction reagent with those of the microorganism itself (biomass), Rhodococcus cloudiness and Rhodococcus erythropolis were analyzed under the same conditions as described above, as shown in FIGS. 2 and 3.
In the IR spectrum of the bacteria (biomass), 1500cm were observed-1The following regions have a large number of adsorption peaks due to the changes in carbon-carbon, carbon-oxygen and carbon-nitrogen bonds that may occur; this area is unique for each substance. In addition, aromatic compounds, aldehydes, ketones and esters were found at 1750--1With a strong peak in between. Mycolic acid is part of the cell envelope, responsible for the hydrophobicity of bacteria, and can be reflected by peaks in alkane, ketone and aldehyde clusters. The presence of amino and aromatic compounds, possibly part of aromatic amino acids, suggests that the protein material plays a decisive role in the flotation and flocculation process.
With respect to the bioreaction reagents, table 1 shows possible functional groups found in infrared spectroscopic analysis. At 3417, 2929, 2855 and 1634, 1629cm-1The alcohol, alkane, alkene and ketone groups found in the region between, respectively, may indicate the presence of mycolic acid. Wavelength of 1400, 1548 and 3350cm-1Recognition of aromatic and amino groups of (a) may indicate the presence of a polar amino acid such as tyrosine.
According to the literature, the proteins present in bacteria and their biologics may be the cause of the flocculation flotation process, because they are amphiphilic.
Table 1: potential functional groups determined in infrared spectroscopic analysis of crude bioreaction reagents.
Example 3
In order to verify another important feature of the bioreactive agent obtained in example 1, the effect of the bioreactive agent on the surface tension of distilled water at neutral pH was evaluated by varying the bioreactive agent concentration from 0ppm to 250 ppm. Surface tension measurements were made by the loop method on a Kruss K10 digital tensiometer. To estimate the Critical Micelle Concentration (CMC), two tangent lines were constructed at the minimum and maximum surface tension points, and the CMC was represented at the intersection of these lines. The CMC was 92ppm for the bioreactive agent from Rhodococcus turbinatus (RoBR) and 62ppm for the bioreactive agent extracted from Rhodococcus erythropolis (ReBR).
FIG. 4 shows surface tension as a function of bioreactive agent concentration. When RoBR is used, the surface tension is reduced to 50.5mN m-1When ReBR is used, the surface tension is reduced to 62mN m-1. The bioreactor may be composed of polymeric substances that do not necessarily reduce surface tension, but may be effective in reducing interfacial tension between immiscible liquids and forming a stable emulsion.
Example 4
To verify the floatability of hematite, a solution having 10 deg.C was used according to the invention-3mol·L-1Improved Hallimond tube with sodium chloride as different electrolytes and air flow of 35dm3min-1And carrying out a micro flocculation test, wherein the mineral particle size fraction is +75-150 microns, the conditioning time is 2 minutes, and the flotation time is 1 minute. The concentration of bioreactive agent varies between 25 and 150ppm and the pH varies between 3 and 11. Buoyancy is calculated as the ratio of the floating mass to the total mass of the mineral.
Figures 6 and 7 show the floatability of hematite when RoBR and ReBR are used, respectively. Both bioreactive agents exhibit similar behavior: maximum floatability (about 90%) of hematite occurs at pH3 with bioreactive agent concentrations of 75 ppm. However, it was found that hematite can be floated at acidic and neutral pH values when RoBR is used, whereas hematite can be floated only at acidic pH values when ReBR is used. The literature indicates that most non-toxic bioreactive agents are anionic. Further, the isoelectric point of hematite is about 5.1. In this way, the pH of the medium can be linked to the adsorption of bioreactive agents on the mineral surface. In acidic media, there is electrostatic attraction between the mineral surface and the anionic bioreactive agent, resulting in maximum adsorption and thus maximum recovery of hematite. On the other hand, in alkaline media, adsorption of bioreactive agents on mineral surfaces will be minimal due to electrostatic repulsion.
Example 5
To verify the floatability zones of calcite, dolomite, apatite, quartz and hematite, tests were carried out under the same conditions as described in example 4. The tests were carried out with pure minerals.
FIGS. 8 and 9 show bar chart compositions comparing the floatability of the different minerals described above using two bioresponse reagents (ReBR and RoBR). Several selective regions (windows) in the studied mineral can be observed, for example:
a) considering that the ore consists of hematite and quartz minerals, it is possible to directly float hematite with RoBR at pH3, 5 and 7, 50 to 150ppm, whereas with ReBR this method is only applicable at pH3 and
b) Considering the minerals composed of apatite and calcite minerals, it has been demonstrated that at pH values of 5, 7 and 9, direct apatite flotation can be carried out using 25ppm RoBR; 50ppm RoBR was used at
c) Considering the minerals consisting of the minerals apatite and dolomite, it has been demonstrated that dolomite can be directly floated in the presence of 25ppm rebr at a pH of 3.
Example 6
The hematite-quartz system was investigated using the same procedure and flotation conditions as listed in example 5. The pH was maintained at 3 and three different hematitesQuartz ratio (25H-75Q; 50H-50Q; 75H-25Q) ReBR and two concentrations (50 mgL)-1And 100mg L-1). The results are shown in Table 2.
Table 2: results of microbiological phase test of hematite-quartz system
The results show that the metallurgical recovery of the concentrations of the two bioreactive agents studied is similar when comparing the same mineral systems. The metallurgical recovery difference was 1% (50 and 100 mg. L) for 25% hematite to 75% quartz ratio-1The recovery rates of the bioreaction reagents were 55.5 and 56.5%, respectively). For 5% hematite to 50% quartz ratios, 50 and 100 mg.L were used-1The recovery rates of iron in the case of the bioreaction reagent were 83.6% and 85.5%, respectively. 50 and 100 mg.L for 75% hematite to 25% quartz ratio-1The metallurgical recovery of the bioreactive reagent was 89.7% and 91.3%, respectively.
The same behaviour can be seen when comparing the mass recovery and iron content of the (flotation) concentrate. Adopts double biological reaction reagents (100 mg. L)-1) There is little interference with the results of the flotation process described above. This effect can be attributed to the RoBR efficiency in the bioflocculation process.
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