A biosynthetic flotation reagent, its preparation method and application

Abstract

This invention belongs to the field of flotation reagent technology, specifically disclosing a biosynthesized flotation reagent, its preparation method, and its application. This invention applies biosynthesized extracellular polysaccharides to flotation, and improves the inhibitory performance of the flotation reagent by optimizing fermentation parameters to alter the structure of the polysaccharide molecules. The novel flotation reagent provided by this invention can achieve efficient separation of sulfide minerals and talc, offering new ideas and methods for solving the problems of current flotation reagents' difficulty in degradation and environmental pollution during production.

Description

Technical Field

[0001] This invention relates to a flotation reagent, specifically to a biosynthetic flotation reagent, its preparation method, and its application. Background Technology

[0002] Talc (Mg3(Si2O5)2(OH)2), a typical magnesium silicate gangue, exhibits excellent natural hydrophobicity, resulting in a non-polar surface. Its low hardness also makes it brittle and prone to mud formation during grinding. In flotation, it readily adheres to the surface of non-ferrous metal ores (such as copper, molybdenum, nickel, and lead), negatively impacting concentrate grade and subsequent smelting processes. Furthermore, talc in the pulp can cause sticky foam, reducing reagent selectivity and hindering the separation of non-ferrous metal ores from talc. Therefore, in the flotation of talc-containing non-ferrous metal ores, selectivity depressants must be added to reduce talc floatability.

[0003] Currently, commonly used talc inhibitors are divided into inorganic and organic inhibitors. Compared to inorganic inhibitors, organic inhibitors (such as carboxymethyl cellulose (CMC), glucon, and methyl chitosan) have stronger selectivity and inhibitory ability against talc. However, due to limited selectivity and high reagent consumption, researchers have chemically modified polysaccharide molecules, such as through carboxymethylation, phosphorylation, and etherification. But mineral processing wastewater containing chemical reagents can cause significant damage to the natural environment.

[0004] Microbial flotation is a green and environmentally friendly mineral processing method that utilizes microorganisms and their metabolites to selectively regulate the physicochemical properties of mineral surfaces, thereby separating valuable minerals from gangue minerals. Therefore, obtaining extracellular polysaccharides through microbial synthesis and using these structurally optimized microbial extracellular polysaccharides for the selective separation of minerals is an efficient and environmentally friendly approach. Summary of the Invention

[0005] To address the technical challenge of talc's fragility and tendency to become muddy during flotation, leading to sticky foam and a deteriorated flotation environment, this invention provides a highly selective flotation reagent for inhibiting talc and its preparation method. This reagent is synthesized by microorganisms, is environmentally friendly, low-cost, easily degradable, and pollution-free, and exhibits outstanding inhibitory effects.

[0006] To achieve the above objectives, the present invention is implemented in the following manner:

[0007] A method for preparing a biosynthetic flotation reagent, obtained by fermentation culture of Xanthomonas campestris.

[0008] The strain has the accession number Xc BNCC-188197 and was purchased from BeiNa Biotechnology.

[0009] In the preparation method described above, at least one of sucrose, glucose, maltose, lactose, soluble starch, and corn starch is selected as the carbon source for the fermentation culture medium, with corn starch and sucrose being preferred as carbon sources.

[0010] The nitrogen sources include urea, ammonium chloride, peptone, yeast powder, and beef extract. Yeast powder is the most preferred. Under the preferred carbon and nitrogen source conditions, microorganisms can synthesize extracellular polysaccharides containing the target active ingredient.

[0011] The preparation method involves inoculating a single colony of *Xanthomonas campestris* strain into a seed culture medium under sterile conditions, and culturing it at 25–37°C and 150–210 rpm until the bacteria reach OD500. 600 The absorbance at the point is 1; the seed fermentation broth is inoculated into the fermentation medium and cultured at 25-37℃ and 150-210rpm for at least 48h.

[0012] Furthermore, single colonies of *Xanthomonas campestris* strain were inoculated into 10 mL of seed culture medium under sterile conditions and cultured at 25–37 °C and 150–210 rpm until the bacteria reached OD500. 600 The absorbance at the point is 1; the seed fermentation broth is inoculated into a fermentation medium containing 100 mL at an inoculation rate of 8-12%, and cultured at an initial pH of 6-8, 25-37℃ and 150-210 rpm for at least 48 h.

[0013] The preparation method described above uses a seed culture medium with the following formula: 20 g / L sucrose, 5 g / L beef extract, 3 g / L peptone, 1 g / L yeast powder, and distilled water to a final volume of 1 L, with a pH of 6–8.

[0014] Fermentation medium formula: corn starch 30-60 g / L, yeast powder 3-4 g / L, calcium carbonate 2-4 g / L, potassium dihydrogen phosphate 2-6 g / L, magnesium sulfate 2-4 g / L, citric acid 1-3 g / L, ferrous sulfate 0.1-0.5 g / L, distilled water to 1 L, pH 6-8.

[0015] In this invention, based on optimizing the composition and ratio of the culture medium, the culture conditions, including the amount of inorganic salts, culture temperature, inoculum size, and initial pH, are further controlled, resulting in a significant increase in the yield, molecular weight, and proportion of active components in the microbial extracellular polysaccharide structure. The microbial extracellular polysaccharide synthesized under the optimal conditions can further enhance the selective inhibition of talc flotation.

[0016] The preparation method described above involves centrifuging, purifying, and drying the fermentation broth after culture to obtain the extracellular polysaccharide.

[0017] The present invention also provides biosynthetic flotation reagents prepared by the method.

[0018] The present invention also provides the application of the aforementioned biosynthetic flotation reagent as a flotation inhibitor, particularly its application as an inhibitor for separating sulfide minerals from talc.

[0019] Furthermore, the amount of flotation inhibitor added is 80-100 mg / L.

[0020] After the culture cycle is completed, the fermentation broth is directly added to the talc-containing slurry, resulting in a significant inhibitory effect and a simple process. Alternatively, the fermentation broth can be purified to obtain microbial extracellular polysaccharides for inhibition.

[0021] The microbial extracellular polysaccharide selected in this invention can enhance the adsorption capacity on the talc surface, reduce the hydrophobicity of the talc surface, and effectively reduce reagent consumption. Simultaneously, the novel flotation reagent exhibits extremely weak adsorption and inhibition capabilities for the non-ferrous metal mineral chalcopyrite, while demonstrating excellent inhibition performance on the gangue mineral talc. Therefore, the novel microbial synthetic talc flotation reagent provided by this invention can efficiently separate talc and chalcopyrite.

[0022] The technical solution of this invention achieves a significant reduction in the recovery rate and grade of talc flotation in a mixed ore flotation system, while being environmentally friendly and cost-effective.

[0023] Beneficial effects

[0024] 1. The present invention has found that the active components in the extracellular polysaccharide structure synthesized by microorganisms are closely related to the types of carbon sources in the culture medium components. Among the carbon sources, only corn starch and sucrose are conducive to the synthesis of active components by microorganisms, and corn starch is more preferred.

[0025] 2. Characterization and comparison of the viscosity-average molecular weight, functional groups, and flotation performance of extracellular polysaccharides synthesized under different culture parameters revealed that the optimal main parameters—corn starch 30–60 g / L, yeast extract 3–4 g / L, calcium carbonate 2–4 g / L, potassium dihydrogen phosphate 2–6 g / L, magnesium sulfate 2–4 g / L, citric acid 1–3 g / L, ferrous sulfate 0.1–0.5 g / L, culture temperature 25–37 °C, inoculum size 10%, and initial pH 6–8—significantly increased the yield of microbial extracellular polysaccharides and improved the separation selectivity of chalcopyrite and talc.

[0026] 3. Currently, talc flotation reagents are mainly chemically synthesized or chemically modified. The high reagent consumption leads to a significant environmental impact, and enterprises face significantly increased costs for subsequent mineral processing wastewater treatment. Developing new talc inhibitors is difficult to reduce dosage and has high synthesis costs. However, the novel microbially synthesized talc flotation reagent provided by this invention has strong separation and inhibition properties, low requirements for the flotation environment, and good applicability. At the same time, the synthesis process is green, environmentally friendly, and inexpensive, significantly reducing the cost of subsequent mineral processing wastewater treatment. It is suitable for industrial scale-up production and application. Attached Figure Description

[0027] Figure 1 This is the NMR H spectrum of the flotation reagent of this invention.

[0028] Figure 2 This is the infrared analysis spectrum of the flotation reagent of this invention.

[0029] Figure 3 This is a flotation flowchart of embodiments 1-3 of the present invention. Detailed Implementation

[0030] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments and accompanying drawings. The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0031] The following are some of the embodiments used by the inventors in their experiments:

[0032] Examples 1-2 and Comparative Examples 1-2: (Talc Single Mineral Flotation Case)

[0033] Example 1 Biosynthetic conditions:

[0034] Fermentation medium composition: corn starch 45g / L, yeast powder 3g / L, calcium carbonate 2g / L, potassium dihydrogen phosphate 4g / L, magnesium sulfate 3g / L, citric acid 2g / L, ferrous sulfate 0.3g / L, distilled water to make up to 1L, pH 7.

[0035] Comparative Example 1 used a preferred corn starch concentration of 25 g / L, and other conditions were the same as in Example 1.

[0036] Example 2 Biosynthesis conditions:

[0037] Fermentation medium composition: corn starch 30g / L, yeast powder 4g / L, calcium carbonate 2g / L, potassium dihydrogen phosphate 5g / L, magnesium sulfate 4g / L, citric acid 3g / L, ferrous sulfate 0.5g / L, distilled water to make up to 1L, pH 7.

[0038] Comparative Example 2 used a preferred amount of 1 g / L of precalcium carbonate, and other conditions were kept the same as in Example 2.

[0039] Biosynthesis procedure: A single colony of *Xanthomonas campestris* strain was inoculated into 10 mL of seed culture medium under sterile conditions and cultured at 30°C and 200 rpm until the bacteria reached the OD value. 600 The absorbance at the specified location was 1. The seed fermentation broth was inoculated at 10% into 100 mL of fermentation medium and cultured at 30℃ and 200 rpm for 48 h. The fermentation broth was then separated and purified to obtain microbial extracellular polysaccharides. The polysaccharide yield was determined by the dry weight after drying, and the viscosity-average molecular weight of the polysaccharides was measured using an Ubbelohde viscometer.

[0040] The seed culture medium formula is as follows: 20 g / L sucrose, 5 g / L beef extract, 3 g / L peptone, 1 g / L yeast powder, and distilled water to make up to 1 L, pH 7.

[0041] The separation and purification process was as follows: First, 5 mL of fermentation broth was taken, diluted with an equal volume of distilled water, and thoroughly mixed. After centrifugation at 10,000 rpm for 25 minutes, the supernatant was extracted. Then, three volumes of ethanol were added and shaken well to allow the extracellular polysaccharides to precipitate completely. The mixture was centrifuged again at 10,000 rpm for 25 minutes, and the supernatant was discarded. Finally, the substrate was dried at 60°C to constant weight to obtain the extracellular polysaccharides.

[0042] Table 1

[0043]

[0044]

[0045] The comparative examples are microbial extracellular polysaccharides synthesized under the culture medium composition formulations reported in the studies, while the examples are microbial extracellular polysaccharides synthesized with optimized culture medium components. As shown in Table 1, compared to comparative examples 1 and 2, examples 1 and 2 with optimized formulations showed significantly increased microbial extracellular polysaccharide yield and viscosity-average molecular weight, as well as enhanced inhibition of talc flotation. This indicates that the optimized culture medium conditions are more suitable for the growth and metabolism of the microorganisms and increase the content of active molecules in the synthesized extracellular polysaccharide molecular structure (e.g., the polysaccharide in example 1). Figure 1 This further proves that the method of synthesizing extracellular polysaccharides by optimizing the microbial culture conditions and using them to inhibit the buoyancy of talc is feasible and effective.

[0046] The differences in functional groups of extracellular polysaccharides synthesized by Xc under different carbon sources were studied using infrared spectroscopy (all polysaccharides were synthesized by fermentation according to the formula in Example 2). Figure 2The infrared spectra of extracellular polysaccharides synthesized by Xanthomonas campestris in different carbon sources are shown: (a) glucose, (b) sucrose, (c) corn starch, (d) malt powder and (e) lactose.

[0047] Figure 2 1720, 1320–1210 and 930cm -1 The peaks at 3650–3600 cm⁻¹ correspond to the stretching vibration absorption peaks of C=O and C–O, and the out-of-plane bending absorption peak of the O–H bond, respectively. This indicates the presence of –COOH in the polysaccharide molecules synthesized from sucrose (b) and corn starch (c) as carbon sources. Furthermore, the peaks at 3650–3600 cm⁻¹... -1 The sharp absorption peaks confirmed the presence of free hydroxyl groups in the polysaccharide molecules synthesized from sucrose (b) and corn starch (c). Infrared spectroscopy analysis explained the significant inhibitory effect of the polysaccharide synthesized from corn starch and sucrose as carbon sources on talc, attributing this to the presence of carboxyl groups (—COOH) and hydroxyl groups (—OH) in the molecule.

[0048] Example 3 and Comparative Example 3: (Flotation Case of Talc-Chalcopyrite 1:1 Mixed Ore)

[0049] Flotation reagents used in Example 3:

[0050] The polysaccharide flotation inhibitor prepared in Example 1 of this invention was used in the same amount as the flotation inhibitor in Comparative Example 3, which was 100 mg / L.

[0051] Collector: Amyl methyl xanthate (PAX), 5 mg / L.

[0052] Foaming agent methyl isobutyl methanol (MIBC), 20 mg / L.

[0053] The flotation reagent used in Comparative Example 3 was methylcellulose.

[0054] During flotation, the amount of methylcellulose added was maintained at the level required for adsorption equilibrium on the talc surface, which was 100 mg / L. The concentrations of other collectors and frothers remained consistent with those in Example 3.

[0055] Flotation process: Add 2g of artificially mixed ore to a 40mL flotation cell, add an appropriate amount of water, stir and aerate for 3 minutes to make it into a slurry, adjust the pH to an appropriate level, add the flotation reagent described in this invention, stir and aerate for 3 minutes, then add the collector and stir for 3 minutes, followed by the frother for 1 minute. Then scrape the concentrate that floats to the surface with the froth, scraping once every 5 seconds for 3 minutes. Weigh and dry the concentrate and tailings separately, and determine the grade and calculate the recovery rate by chemical analysis, as shown in Table 2. The flotation process is as follows. Figure 3 As shown.

[0056] Table 2

[0057]

[0058] As shown in Table 2, under the same reagent dosage and pH conditions, compared with methylcellulose, the flotation reagent of the present invention can significantly improve the recovery rate and grade of the valuable mineral chalcopyrite, while reducing the recovery rate and grade of talc. This indicates that the flotation reagent of the present invention can efficiently separate high-talc-type copper sulfide ores. More importantly, the flotation reagent of the present invention can maintain strong inhibition and separation properties of talc even at low dosages, which is beneficial for reducing flotation costs and environmental protection.

Claims

1. Use of biosynthetic flotation reagent as a flotation depressant, characterized in that, The flotation depressant is a depressant for separating sulfide minerals from talc, and the method for preparing the biosynthetic flotation reagent comprises the following steps: Xanthomonas campestris is obtained by fermentation culture of the bacteria.

2. Use according to claim 1, characterized in that, The preservation number of the strain is X.c BNCC-188197.

3. Use according to claim 1, characterized in that, The fermentation medium selects at least one of sucrose, glucose, maltose, lactose, soluble starch and corn starch as a carbon source of the medium; and selects at least one of urea, ammonium chloride, peptone, yeast powder and beef extract as a nitrogen source.

4. The production method according to claim 3, characterized by, The fermentation medium selects corn starch or sucrose as a carbon source; and selects yeast powder as a nitrogen source.

5. The use according to claim 1, characterized in that, Inoculation of seed medium under aseptic conditions Xanthomonas campestris A single colony of the strain was inoculated into 5 ml of seed medium and grown at 25-37 °C and 150-210 rpm until the bacteria reached an optical density at OD 600 600 of 1. The seed broth was inoculated into 50 ml of fermentation medium and grown at 25-37 °C and 150-210 rpm for 48 h.

6. Use according to claim 1, characterized in that, Inoculation of 10 mL seed medium under aseptic conditions Xanthomonas campestris Single colony of the strain was inoculated into 10 mL seed medium and grown at 25-37 °C and 150-210 rpm until the bacteria reached an optical density at OD 600 The seed broth was inoculated into 100 mL fermentation medium at a ratio of 8-12% and grown at 25-37 °C and 150-210 rpm for at least 48 h.

7. Use according to claim 1, characterized in that, The fermentation medium formula is: corn starch 30~60 g / L, yeast powder 3~4 g / L, calcium carbonate 2~4 g / L, potassium dihydrogen phosphate 2~6 g / L, magnesium sulfate 2~4 g / L, citric acid 1~3 g / L, ferrous sulfate 0.1~0.5 g / L, pH 6~8.

8. The use according to claim 1, characterized in that, The extracellular polysaccharide obtained by centrifugation, purification and drying of the fermentation liquor after the culture is ended.

9. The use according to claim 1, characterized in that, The adding amount of the flotation inhibitor is 80-100 mg / L.

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