Biologically induced sorting of chalcopyrite and galena

I. Overview

Using associated cell outside a microorganism and biopolymers galena selective separation of binary mixtures has been reported from galena and sphalerite or pyrite. In this study, Paenibacillus poly-myxa (B. polymyxa, abbreviated as P. polymyxa) is a Gram-positive bacterium, neutrophilic, surrounded by flagellated heterotrophic organisms, and survives in many deposits. In addition to the main biopolymers such as exopolysaccharides and proteins, the main products of P. polymyxa metabolism contain organic acids such as oxalic acid, formic acid and acetic acid.

In addition to induction of copper ore sorting yellow galena and microbial bio-sourced polymer study, the effects on the organisms themselves understand the sorting process is required. The affinity for bacterial effects and the adjustment of biopolymer's attachment behavior have been studied. However, there is still a need to understand the biopolymers present at the mineral and bacterial interfaces and their role in the attachment process. This article will determine the affinity of chalcopyrite and galena for extracellular biopolymers such as extracellular proteins (EBP) and extracellular polysaccharides (ECP). The relationship between the surface hydrophobicity associated with floatability and the adsorption of biopharmaceuticals was also investigated.

Second, raw materials and test methods

(a) minerals

Samples were collected from Almin-Rock, Indscer Fabriks, India, and hand-selected high purity chalcopyrite and galena samples. Chemical analysis, X-ray analysis, and mineralogical analysis are used to determine the purity of the sample. The purity of chalcopyrite and galena samples was 99.8% and 99.7%, respectively. The above samples were finely ground using a porcelain ball mill and sieved into -105 + 74 Î¼m and -37 Î¼m pellets. Further ball milling was carried out at -37 Î¼m particle size, and a -5 Î¼m particle size was obtained by sedimentation. The samples were subjected to particle size analysis using a Malvern Zetasizer particle size analyzer with an average particle size of 3 to 5 Î¼m. This fraction is used for adsorption and flocculation tests. The specific surface area of â€‹â€‹the sample was determined using a BET nitrogen adsorption method. The chalcopyrite obtained by the above method had a specific surface area of â€‹â€‹1.93 m ² /g. The galena is 1.939 m ³ /g. The -105+74 Î¼m fraction was used for flotation studies.

(two) bacterial culture

The Institute was obtained from the National Industrial Microbial Specimen Laboratory in the National Chemical Laboratory of India using the P. polymyxa strain (numbered NCIM2639). The culture was carried out in the laboratory using Bromfield medium. Potassium nitrate was used to maintain ionic strength, and nitric acid and potassium hydroxide were used as pH adjusters. All reagents in the test were of analytical grade. Distillation deionized water with a specific conductivity <1.5 Î¼S/m was used in the test. 10 mL of the pure strain was injected into Bromfield medium for culture. The culture was carried out in a Remi incubator at 30 Â° C and a rotational speed of 340 r/min. The pH change was measured every 30 min using a Systronics digital pH meter.

(3) Preparation of cell-free metabolites

Bacteria (48 h) grown at 4 Â°C were centrifuged for 15 min in a Sorvall RC-5B centrifuge (10000 r/min). The supernatant was decanted and filtered through sterile Millipore (pore size o. 2 Î¼m) to remove all insoluble materials while removing bacterial cells. The cell spheres were washed with a second distillation of deionized water and then centrifuged. The above procedure was repeated twice to obtain a pure cell sphere.

(4) Separating proteins from metabolites

After 48 h incubation, 1 LP. polymyxa broth was centrifuged. The supernatant was filtered through a Millipore (pore size 0.2 Î¼m) filter paper. Under the constant shaking at 4 Â° C, the analytically pure ultrafine granular sulfuric acid was slowly added at a concentration of 90% (600.16 g/L). The solution was cooled at 4 Â° C for 12 h. The protein precipitate was dissolved in 1 mol/L of a solution of tris (hydroxymethyl) aminomethane hydrochloride buffer (pH 7). Dialysis was carried out at 4 Â° C for 18 h. The precipitate produced during dialysis was removed by centrifugation. The supernatant was frozen, weighed and stored at 4 Â°C.

(5) Separation of extracellular polysaccharide (ECP) from metabolites

1 L was centrifuged to remove the cells for 48 h. The supernatant containing ECP was filtered through a sterile Millipore membrane. It was then lyophilized to 200 mL under vacuum at -80 Â°C using a Virtis Freezemobile 12EL freezer. The dehydrated solid matter was dissolved in 10 mL of distilled millipore high purity water at room temperature and cooled below 10 Â°C. 20 mL of secondary distilled ethanol was added to precipitate ECP and it was separated from other bacteria-containing supernatants. The above ethanol precipitation was repeated two to three times to further purify the polysaccharide. The polysaccharide solution was dialyzed against double distilled water. Prior to dialysis, the dialysis tubing was boiled in a water bath of 0.01 mol/L EDTA and 2% sodium bicarbonate solution for 10-15 min. After dialysis, the ECP was stored at low temperature (4 Â° C). The purity of ECP is determined by the phenol-sulfuric acid method.

(6) Adsorption test

1 g of the mineral sample was added to a 100 mL 10 ^-3 mol/L KNO ₃ solution of known pH and EBP concentration in a 250 mL Erlenmeyer flask. The Remi oscillator was used to shake for 15 min at 30 Â° C and 250 r/min. After equilibration, the pH of the slurry was measured again. It was then centrifuged at 200 r/min for 5 min to remove the mineral particles to which EBP adhered. The supernatant containing EBP was further filtered with Whatman No. 42 filter paper, and the concentration of EBP remaining in the supernatant was measured. A similar method was used to study the adsorption behavior of bacterial cells and ECP on mineral particles.

(7) Flocculation research

In the flocculation study, 1 g of the mineral sample was dispersed in 100 mL of twice-distilled deionized water in a graduated cylinder of 100 mL volume. The amount of the stopper was turned upside down and inverted 10 times, and then allowed to stand for 2 minutes. Using a pipette, remove 90 ml of the supernatant and place it in a beaker. The supernatant was filtered, dried and weighed to obtain a mass fraction of solid particle dispersion. The test was carried out with pH and time as variables. A flocculation test was carried out in a graduated cylinder containing 1 g of 50 mL of slurry and 50 mL of protein supernatant or a known concentration of ECP plus a 100 mL stopper. The pH of the pulp and protein was adjusted to the same value before mixing. The selective flocculation test was carried out in a binary mixture of 1:1 by weight of galena and chalcopyrite. Containing 0.5 g of 50 ml, the added slurry is added to the graduated cylinder with 50 mL of the added bacterial supernatant. Prior to mixing, the slurry and cell supernatant were adjusted to the same pH. The cylinder with the stopper was inverted 10 times and allowed to stand for 2 minutes (de-slurry stage). The dispersed and settled products were analyzed by ICP spectroscopy to obtain the mass fraction of each mineral in both products.

(8) Microflotation test

At neutral pH, 1 g of mineral was mixed with 100 mL of secondary distilled deionized water containing known concentrations of EBP, ECP or bacterial cells in an Erlenmeyer flask. The flask was incubated for 30 min in a 250 r/min shaker. After the action, the supernatant is removed and the mineral particles are separated. The mineral particles sinking at the bottom were filtered through Whatman No. 42 filter paper and washed with a second distillation of deionized water to remove EBP, ECP or cells adhering to the mineral surface. Transfer the conditioned minerals to a modified Harrison flotation tube. Transfer 40 mL of /min nitrogen for 3 min. The settled and floated portions were separated and dried and weighed separately. Potassium isopropyl xanthate (PIPX) was used as a collector to study flotation behavior. At the same time, the effect of the order of addition of collectors and bacterial reagents on flotation was studied. 1 g of a mineral having a degree of -105 + 74 Î¼m (1:1 weight ratio) was suspended in a 200 mL addition solution. Prior to flotation, the mineral mixture acts with different bacteria. The mineral mixed sample was mixed with a solution of known pH for 15-20 min with a magnetic stirrer. Then a flotation test was conducted. The floated minerals were measured by ICP and the recovery was calculated.

(9) SEM analysis

Bacterial cells were obtained after centrifugation at 10,000 r/min for 15 min. The cell spheres were resuspended in secondary distilled deionized water. Wash the mineral particles twice with water through nitrogen. 0.5 g of mineral was suspended in 50 mL of water (NW) containing nitrogen. The mineral particles obtained above are interacted with a known number of cells. It was applied in an Erlenmeyer flask and then transferred to an Eppendorf tube and centrifuged at 5000 r/min. Add 5% glutaraldehyde, just enough to immerse the mineral sample, stir at 100 r/min for 2 h, then stir with 0.5% glutaraldehyde for another 2 h. The mineral sample was then adjusted with 35% ethanol. Remove 0.5 mL of the extract with a micropipette, take a drop onto the covered slide, dry it in the dry machine for 15 min, then add a drop (50%) of ethanol. Dry for 15min. The above procedure was then repeated with 70% and 95% ethanol. After complete dry operation, the drying was carried out sequentially with acetone at a concentration of 35%, 50%, 70% and 95%. Store the coverslip in a desiccator until an SEM test (not to exceed 12 h).

Third, the results and discussion

(1) Adsorption research

Firstly, the relationship between the adsorption behavior of BBS and ECP on the surface of galena and chalcopyrite and the change of action time and pH was established. The results are shown in Figures 1 and 2. Figure 1 is a scanning electron micrograph of the adhesion of bacterial cells to chalcopyrite and galena. It can be seen from the figure that the affinity of bacterial cells for both minerals is relatively large. The adsorption kinetics curves of bacterial cells were obtained by measuring the change of adsorption density of different components on the mineral surface with time. The adsorption behavior was observed with time at 10 ^-3 mol/L KNO ₃ and pH 6.5-7. The cell concentration was 4 x 109 cells/mL before adsorption. Figure 2, a shows that the adsorption density of bacterial cells on chalcopyrite is 1.5 x 109 cells/m ² after 15 min of action, and 1 x 109 cells/m ² on galena. This indicates that the adsorption of bacterial cells on minerals is not selective. The literature indicates that the cell wall contains polysaccharides and proteins. Therefore, the adsorption behavior of EBP was investigated at an initial EBP concentration of 4 mg/g mineral. Figure 2, a shows that the adsorption density of EBP on chalcopyrite is 3 mg/m ² after 15 min, while galena is less than 1 mg/m ² . The adsorption behavior of ECP was also studied at an initial concentration of EPC of 10 mg/g. Figure 2, a shows that after 15 min of action, more than 9 mg/m ² ECP is adsorbed on chalcopyrite, while the adsorption on galena is less than 8 mg/m ² . After 15 minutes of action with the two minerals, the ECP is saturated on the mineral surface. However, the amount of adsorption of EBP and ECP on chalcopyrite and galena is not as large as the adsorption of bacterial cells on the surface of these two minerals.

Figure 1 SEM photograph of P. polymyxa, bacterial cells in chalcopyrite (a) and galena (b)

Figure 2, b is the bacterial cell, the amount of adsorption of EBP and ECP on the mineral as a function of pH. In all pH, the adsorption density in the bacterial cells are larger than the yellow silver ore in the galena. In the acidic range. The adsorption density on chalcopyrite is higher than that on galena. For chalcopyrite, as the pH increases, the bacterial cell adsorption density decreases sharply. The adsorption density of EBP on chalcopyrite is uniform in the acidic pH range, which is 3 mg/m ^{2 in the} neutral range. For galena, the adsorption amount is relatively uniform throughout the pH range, and the maximum adsorption density is 1 mg. /m ² . The adsorption density of ECP on chalcopyrite varies from 4 mg/m ² to 8 mg/m ² at pH 3-8. Similar behavior was observed for galena. The adsorption behavior of ECP in chalcopyrite and galena in the acidic pH range is similar to that in the alkaline range. However, EBP adsorbs more on chalcopyrite in the acidic and alkaline pH range than on galena.

Figure 2 Above: P. polymyxa cells, ECP and EBP in chalcopyrite at pH 6.5-7

And the adsorption density on galena with time (pH 6.56.7);

Bottom: P. polymyxa cells, ECP and EBP in chalcopyrite and galena to mine

Adsorption density changes with pH (15 min)

â– -bacterial cells + chalcopyrite; â—-bacterial cells + galena; â–¡-ECP+ chalcopyrite;

â—‹-ECP+ galena; â–³-EBP+ chalcopyrite; â–³-EBP+ galena

(2) Flocculation test

The sedimentation behavior of chalcopyrite and galena fines at different times and pH in the presence of different biological agents and bacterial cells was determined. Figure 3 shows the sedimentation behavior of chalcopyrite and galena with time. Figure 3, a shows that at pH 6.5 to 7, after 15 minutes of action, the chalcopyrite increased from 30% in the absence of bacterial cells to 90% in the presence of bacterial cells. The bacterial cell wall contains polysaccharides and proteins. Therefore, the change of the flocculation rate of minerals with the action time in the presence of EBP and ECP was investigated. The flocculation rate was 95% when the chalcopyrite was treated with EBP for 15 min; while in the presence of ECP, only a small amount of chalcopyrite flocculated. The action of bacterial cells and EBP promoted flocculation of a large number of fine-grained chalcopyrites, and there was no significant change in flocculation of fine-grained chalcopyrite in the presence of only ECP (Fig. 3, b and c). The sedimentation rate of the 15 min galena increased from 35% in the absence of cells to 90% in the presence of cells. However, at EBP, the sedimentation rate of the 15 min galena was reduced to less than 20%, and the sedimentation rate was 30% without any agent. The flocculation rate of galena and ECP after 15 minutes is higher than 90%, and the flocculation rate is 35% without any reagent. The specificity of bacterial cells and biological agents is attributed to the specific functional groups on the mineral and bacterial cell walls. When testing the flocculation effect of chalcopyrite and galena, each mineral settled for 15 min. When working with EBP, the sedimentation rate of chalcopyrite (95% in 15 min) is higher than the high sedimentation rate of galena (20% in 15 min). After interaction with ECP, about 30% of the chalcopyrite and more than 90% of the galena deposits settle within 15 min. The sedimentation behavior of mineral and bacterial cells, EBP and ECP at different pH is shown in Figure 4. Figure 4, a shows that in the absence of any drug, 90% of the chalcopyrite settles at pH ³ , while at pH 9, the sedimentation rate is reduced to 40%. About 90% of the chalcopyrite settles at pH 3-9 and in the presence of bacterial cells and EBP. The galena has a sedimentation rate of 55% without any agent and pH 3, and a sedimentation rate of 35% at pH 9.

Figure 3 Chalcopyrite and galena in the presence of bacterial cells (top), ESP (middle)

Relationship between settlement and settlement time in the presence of ECP (bottom)

1-Chalcopyrite; 2-galena; 3-Chalcopyrite + bacterial cell; 4-galena + fine cell;

5-Chrysanthemum + EBP; 6-galena + EBP; 7 - chalcopyrite + ECP; 8 side lead + ECP

Figure 4 Chalcopyrite and galena in bacterial cells (top), EBP (middle)

Relationship between sedimentation and pH in the presence of ECP (bottom)

1-Chalcopyrite; 2-galena; 3-Chalcopyrite + bacterial cell; 4-galena + bacterial cell;

5-Chrysanthemum + EBP; 6-galena + EBP; 7 - chalcopyrite + ECP; 8-galena + ECP

However, in the presence of bacterial cells, the sedimentation rate of the ore particles increases. Almost 90% of the galena precipitates after acting on bacterial cells. Figure 4, b shows that the sedimentation rate of the Huangtong Mine is 90% in the absence of medicinal herbs and pH3, while the sedimentation rate drops to 40% at pH 9. In the presence of EBP and pH3, the chalcopyrite sedimentation rate is 92%, the pH7 sedimentation rate is 95%, the sedimentation rate is reduced to 65% at pH 9, and the galena sedimentation rate is 55% in the absence of the agent and pH3. The pH 9 sedimentation rate was 35%. However, galena has a sedimentation rate of 30% in the pH 3 range and a 20% reduction in pH 9. This indicates that galena is dispersed in the presence of EBP. Figure 4, c shows that the chalcopyrite sedimentation rate is 90% in the absence of any agent and pH3, and the sedimentation rate is reduced to 40% at pH 9. However, in the presence of ECP, the sedimentation rate of chalcopyrite is small, indicating that ECP has no major effect. The sedimentation rate of galena was 55% without any agent and pH 3, and the sedimentation rate was reduced to 35% at pH 9. However, in the presence of ECP, galena flocculation is significantly increased. 95% of the lead ore is flocculated in the range of pH 3 to 9.

The floc formed by bacterial cells/biological reagents and minerals is a three-dimensional disc. SEM photographs of the flocs indicate that the bacterial cells are mixed with the minerals and wrapped around each other. Early studies have shown that cell surface tissue has a specific affinity for different minerals. Therefore, the bacterial cell wall acts as a bridge between minerals and bacterial cells to connect them into a three-dimensional structure. The SEM flocs are shown in Figures 5 and 6. Biological agents (EBP) produced by bacteria also form mineral flocs.

Figure 5 SEM photograph and schematic diagram of flocs formed by mineral and bacterial cells

Figure 6 SEM photograph and schematic representation of the floc formed by minerals and extracellular products

(III) Selective flocculation research

The selective separation of galena from binary mixtures of chalcopyrite and galena with bacterial cells, EBP and ECP was tested. It can be seen from the results in Table 1 that 71.4% of galena can be isolated in the presence of bacterial cells, and 92.3% of galena can be isolated in the presence of EBP. At pH 8.5-9, 70.2% of galena can be isolated in the presence of bacterial cells, and 89.7% of galena can be isolated in the presence of EBP.

Table 1 EBP in bacterial cells (5 Ã— 108 cells / mL) and P. Polreyxa

Selective flocculation of chalcopyrite from a mixture of chalcopyrite and galena (mass ratio 1:1) in the presence of (50 mg/g)

Desliming section number (3 minutes each)	Galena removal (cumulative) /% at different pH
	6.5~7		8.5~9
	cell	EBP	cell	EBP
1 2 3 4 5	22.6 41.8 61.8 68.0 71.4	25.6 49.7 69.9 81.2 92.3	31.2 56.7 62.3 69.8 70.2	33.0 45.6 70.2 85.1 89.7

Figure 4, c results show that ECP does not significantly affect the sedimentation rate of chalcopyrite. The separation of galena from the binary mixture of chalcopyrite and galena after the action with ECP was also observed. Table 2 shows that in the range of pH 6.5 to 7, 87.2% of chalcopyrite can be separated, and 81% of chalcopyrite can be separated in the range of pH 8 to 8.5.

Table 2 ECP (l00mg/g) isolated from P. polymyxa, bacterial supernatant

Selective flocculation of chalcopyrite from a mixture of chalcopyrite and galena (mass ratio 1:1) in existence

Desliming section number (2 min per segment)	Chalcopyrite removal rate at different pH (cumulative) /%
Desliming section number (2 min per segment)	6.5~7	8~8.5
1 2 3 4 5	40.1 62.3 71.9 82.3 87.2	35.0 59.7 68.7 79.6 81.0

(4) Microflotation test

The flotation behavior of chalcopyrite and galena after treatment with bacterial cells, EBP and ECP was also studied. Mineral flotation behavior after interaction with EBP and ECP in the presence of a collector such as PIPX was determined. As can be seen from Figure 7, the flotation recovery of chalcopyrite was 20% after treatment with bacterial cells, EBP and ECP. However, after acting with EBP, galena exhibits hydrophobic behavior. At pH 3, the flotation recovery of galena increased from 25% to 45% after EBP. At pH 6, the flotation recovery was 65% and pH 9 was reduced to 45%. However, after treatment with bacterial cells and ECP, the recovery of galena was reduced.

Figure 7 Chalcopyrite after treatment with bacterial cells and ECP at different pHs (top)

And galena (bottom) flotation recovery

â–¡-not acting with the agent; â—-acting with bacterial cells; â–²-acting with EBP; â–²-acting with ECP

(5) Micro-separation flotation test

After studying the flotation behavior of single minerals treated with different biological agents, the possibility of separating chalcopyrite from a binary mixture of chalcopyrite and galena with different biological agents was investigated. In order to improve the separation efficiency, potassium isopropyl xanthate (PIPX) was added. Table 3 shows the results of selective flotation separation experiments using bacterial cells, EBP and ECP. It can be seen from Table 3 that after the action with bacterial cells, the recovery of chalcopyrite in the mixture was 49.9% and the recovery of galena was 44% after adjustment by PIPX (1Ã—10 ^-3 mol/L). When the PIPX concentration was reduced to 5Ã—10 ^-4 mol/L, the recovery of chalcopyrite was 44.4%, and the recovery of galena was 37.2%. However, when the mixture first interacted with PIPX (1 Ã— 10 ^-3 mil / L) and then with bacterial cells, the recovery of chalcopyrite was 48%, and the recovery of galena was 47.9%. When PIPX concentration When the temperature is reduced to 5Ã—10 ^-4 mol/L, the recovery rate of chalcopyrite is 39.2%, and the recovery rate of galena is 38.8%. When the mixture was first reacted with EBP and then with PIPX (5Ã—10 ^-4 mol/L), the recovery of chalcopyrite was 29.1% and the galena was 81.4%. However, after the action with ECP, the flotation recovery of chalcopyrite was 49.6%, and the recovery of galena was 14.1%.

Table 3 Separation and flotation results of chalcopyrite and galena after treatment with bacterial cells, EBP and ECP at pH 6-6.5 using PIPX as a collector

Test conditions	Cell/biological Reagent concentration	PIPX concentration /molÂ·L ^-1	Chalcopyrite Recovery rate/%	Galena Recovery rate/%
First interact with cells and then treated with PIPX	2 Ã— 10 ⁹ cells / mL	1Ã—10 ^-3	49.9	44
First with the fine package, then with PIPX		5Ã—10 ^-4	44.4	37.2
First with PIPX, then cell treatment	2 Ã— 10 ⁹ cells / mL	1Ã—10 ^-3	48	47.9
First with PIPX, then cell treatment		5Ã—10 ^-4	39.2	38.8
First with EBP, then with PIPX	50mg/g	5Ã—10 ^-4	29.1	81.4
First with EBP, then with PIPX	100mg/g	5Ã—10 ^-4	49.6	14.1

Fourth, the conclusion

The main conclusions can be obtained from the results of this test.

(a) Paenibacillus polymyxa cells can be strongly adsorbed on the surface of chalcopyrite and galena.

(b) However, bacterial extracellular products, such as biological proteins and exopolysaccharides, adsorb more on chalcopyrite than galena.

(3) The degree of flocculation of chalcopyrite and galena is enhanced after the action of bacteria. Promotes chalcopyrite flocculation after interaction with biological proteins, whereas exopolysaccharide enhances flocculation of galena.

(d) When the pH is higher than 6, the biological protein enhances the flotation of galena.

(v) At natural pH, galena and chalcopyrite can be effectively separated by biologically induced flocculation by controlling the regulation of biological proteins and exopolysaccharides. Similarly, first action with biological proteins enhances selective flotation of galena from chalcopyrite.

Ultrasonic Pest Repellent

Ultrasonic Pest Repellent,Ultrasonic Animal Repeller,,Solar Animal Repeller,Environmentally Solar Pest Repeller

SHAOXING SUNSHINE ELECTRONIC CO.,LTD , https://www.ultralitelamp.com