Method for enhancing flotation of microcrystalline graphite by using biomass derivative

Abstract

The invention relates to a method for enhancing flotation of microcrystalline graphite by utilizing a biomass derivative, and belongs to the technical field of purification of natural microcrystalline graphite. The method comprises the following steps: uniformly mixing a microcrystalline graphite powder raw material with water to obtain an ore pulp solution, and adding a pH regulator to regulate the pH value of the ore pulp to 8-9; then, an inhibitor, a collecting agent and a foaming agent are added, and primary roughing concentrate is obtained through air inflation, foam scraping and flotation; the collecting agent is emulsified kerosene containing biomass derivatives; the biomass derivative contains a saponin extract; and during flotation, the use amount of the inhibitor is 1500-2000 g / t, the use amount of the collecting agent is 1000-2000 g / t, and the use amount of the foaming agent is 250-750 g / t. According to the method, the fixed carbon content of the low-grade natural microcrystalline graphite ore can be increased to about 75% through one-time roughing, and the recovery rate is increased to 87% or above.

Description

Technical Field

[0001] The invention relates to a microcrystalline graphite flotation method using latent biomass to prepare a natural surfactant to emulsify kerosene and coupled with ultrasonic enhancement, belonging to the technical field of mineral processing and purification. Background Art

[0002] Microcrystalline graphite has become an important raw material for high-tech products such as batteries, lubricants, and conductive materials due to its excellent conductivity, lubricity, and high temperature resistance. However, natural microcrystalline graphite often contains a variety of impurities, such as minerals, metal elements, and non-metallic elements, which can significantly affect its performance and application value. Flotation, as a mature mineral separation technology, utilizes the differences in surface properties between different minerals to achieve mineral separation through the attachment and separation of bubbles. This method has the advantages of simple operation, low cost, and strong adaptability, and is particularly suitable for processing complex ores and separating multiple impurities.

[0003] With the increasing awareness of environmental protection and the promotion of the concept of sustainable development, researchers have begun to explore ways to reduce the amount of kerosene used by emulsifying kerosene. However, people often use traditional chemical surfactants to emulsify kerosene. However, most common surfactants are synthetic chemicals. Although they can effectively improve flotation efficiency, they often have problems such as toxicity and environmental pollution. Their use in industrial applications is gradually restricted.

[0004] In the prior art, people have tried to flotation microcrystalline graphite. For example, the paper "Experimental Study on Flotation Purification of Low-grade Cryptocrystalline Graphite" published by Weng Xiaoqing involves a set of better flotation schemes, specifically: the mass fraction of microcrystalline graphite ore slurry is 10%, the amount of water glass is 1500g / t, the amount of emulsified diesel is 6000 g / t, the amount of MIBC is 500 g / t, one roughing and four fine cleaning, which can increase the fixed carbon content of the original ore from 53.30% to 84%, and the carbon recovery rate is 81.12%.

[0005] The search revealed that there are few reports on the technology of using organic extracts containing saponins as flotation agents to float microcrystalline graphite. Summary of the invention

[0006] In view of the problems that the existing natural microcrystalline graphite is difficult to purify in conventional flotation processes, has low fixed carbon content after purification, and has low recovery rate, and the use of chemical surfactants to emulsify kerosene as a collector has the problems of high toxicity and environmental pollution. The present invention provides for the first time a method for strengthening the flotation of microcrystalline graphite using biomass derivatives, that is, on the basis of traditional graphite flotation technology, an ultrasonic combined with saponin natural surfactant extract is used to emulsify kerosene, which promotes the particle size of the emulsified kerosene to reach the micrometer or even nanometer level, creates favorable conditions for the reaction between kerosene and fine-grained cryptocrystalline graphite, and increases the collision probability between kerosene microemulsion and microcrystalline graphite particles. It can not only reduce the amount of kerosene used, improve the flotation rate and recovery rate of microcrystalline graphite, but also reduce environmental impact and safety risks, and has broad application prospects.

[0007] The present invention discloses a method for enhancing the flotation of microcrystalline graphite by using biomass derivatives, comprising the following steps: The microcrystalline graphite powder raw material is mixed evenly with water to obtain a pulp solution, and a pH adjuster is added to adjust the pH value of the pulp to 8-9; then an inhibitor, a collector and a frother are added to perform aeration scraping flotation to obtain a primary roughing concentrate; the collector is emulsified kerosene containing a biomass derivative; and the biomass derivative contains a saponin extract.

[0008] The present invention discloses a method for strengthening the flotation of microcrystalline graphite by using biomass derivatives, wherein the saponin extract is obtained by the following process: Step 1 The biomass is placed in a drying oven for drying, and then crushed and sieved; the biomass is selected from at least one of Gleditsia sinensis and Soapberry; Step 2 Weigh the powder obtained in step 1, add it to water, and stir at 60°C to 80°C for at least 2 hours; filter; and collect the filtrate; Step 3 The filtrate collected in step 2 is concentrated under vacuum to evaporate water to obtain a concentrated saponin extract; during vacuum concentration, the heating temperature is less than or equal to 60° C. and the vacuum degree is 0.1-0.5 atm; Step 4 Add ethanol to the saponin concentrated extract obtained in step 3, and place the dissolved solution in a centrifuge for centrifugation to obtain a light yellow saponin viscous liquid, which is a relatively pure saponin component.

[0009] When used in industry, the soapberry peel is taken and the seeds of the soapberry are removed; the soapberry peel and / or the seeded soapberry are placed in a drying oven at 45-55° C. and dried for at least 12 hours, preferably 20-28 hours; the dried biomass is placed in a ball mill and ground, passed through a 50-mesh sieve, and the sieved material is taken. The sieved material is further ground until all of it passes through the sieve.

[0010] When used in industry, the powder obtained in step 1 is added to water at a mass ratio of powder: water = 1: 8-25, preferably 1: 10-20, and stirred at 60°C-80°C for 2-6 hours. Then filter; take the filtrate. In order to improve the extraction rate of saponin extract, after the first extraction of a batch of biomass powder, the filter residue can continue to be extracted, and the extraction is repeated several times until the filtrate no longer produces obvious foam, and the filtrate is combined. When filtering, a vacuum pump can be considered to collect the filtrate.

[0011] Preferably, during the vacuum concentration in step 3, the heating method is steam heating, the heating temperature is 40° C. to 60° C., the vacuum degree is 0.1 to 0.5 atm, and the concentration time is 1 to 3 hours.

[0012] In step 4, 5 to 15 times, preferably 8 to 12 times, volume of 90 to 95% ethanol is added to the saponin concentrate, the dissolved solution is placed in a centrifuge at a speed of 3000 to 5000 r / min, preferably 3500 to 4500 r / min, centrifuged for at least 8 min, preferably 8 to 15 min, the supernatant is taken and the ethanol is recovered by vacuum distillation, the operation is repeated at least 2 times, preferably 3 times, to obtain a light yellow saponin viscous liquid, and a relatively pure saponin component is obtained.

[0013] The present invention discloses a method for strengthening the flotation of microcrystalline graphite by using biomass derivatives. The saponin viscous liquid obtained in step 4 is heated and mixed with kerosene in a water bath to obtain a kerosene microemulsion, and the kerosene microemulsion is emulsified by ultrasound to obtain a stable emulsified kerosene as a collector for subsequent flotation of microcrystalline graphite. The addition amount of the light yellow saponin viscous liquid saponin viscous liquid is between 1% and 10% of the total volume of kerosene, preferably 2% to 10%, and more preferably 4% to 10%. The water bath heating temperature is 50 to 60° C., the stirring rate is 800 to 1200 r / min, and the time is 4 to 6 min to obtain a kerosene microemulsion.

[0014] When ultrasonic emulsification is used for kerosene microemulsion, the ultrasonic power is 10~60W and the ultrasonic emulsification treatment time is 5~10min.

[0015] The fixed carbon content of the raw microcrystalline graphite is 35%~60%; the microcrystalline graphite powder with a particle size of -200 mesh accounts for more than 95% of the total volume of the raw microcrystalline graphite powder. When used in industry, the dried microcrystalline graphite blocks are crushed into graphite particles, and then ball milled to obtain the raw microcrystalline graphite powder.

[0016] The present invention discloses a method for enhancing the flotation of microcrystalline graphite by using biomass derivatives, wherein the concentration of the slurry solution is 7wt.% to 11wt.%. The pH adjusting agent CaO and / or Na 2 CO 3Finally, adjust the pH of the slurry to 8~9.

[0017] The present invention discloses a method for strengthening the flotation of microcrystalline graphite by using biomass derivatives, wherein the dosage of the depressant is 1500-2000 g / t, preferably 1500-1800 g / t; the dosage of the collector is 1000-2000 g / t, preferably 1000-1900 g / t, more preferably 1000-1600 g / t; the dosage of the frother is 250-750 g / t, preferably 250-650 g / t, more preferably 250-550 g / t.

[0018] The inhibitor is selected from at least one of sodium silicate, water glass and sodium carboxymethyl cellulose; The collector is emulsified kerosene containing saponin extract; The foaming agent is selected from at least one of methyl isobutyl carbinol, sec-octanol and terpineol.

[0019] The main differences between microcrystalline graphite and flake graphite are structure, physical properties and application areas. Microcrystalline graphite is composed of tiny and irregularly shaped graphite crystals, usually with low conductivity and lubricity, and is mostly used in refractory materials and coatings, while flake graphite is composed of larger, flat layered graphite sheets, with excellent conductivity and lubricity, and is widely used in high-tech fields such as batteries and conductive materials. In the flotation process, the flotation difficulty of microcrystalline graphite is much higher than that of flake graphite, because microcrystalline graphite particles are small and irregular in shape, easily entrained by foam and difficult to separate, and there are more impurities in the ore, which affects the recovery rate; while the flake structure of flake graphite is easy to capture and separate, and the ore is relatively pure, and the flotation process structure is simplified. Therefore, the flotation process of microcrystalline graphite is complicated, and the reagents and parameters need to be strictly controlled.

[0020] The method of the present invention can increase the fixed carbon content of low-grade natural microcrystalline graphite ore to more than 73% through a single roughing, and the recovery rate is increased to more than 85%. After optimization, the fixed carbon content of low-grade natural microcrystalline graphite ore can be increased to more than 74.2% through a single roughing, and the recovery rate is increased to more than 87.5%.

[0021] The beneficial effects of the present invention are: (1) The present invention extracts natural surfactants from the biomass of Gleditsia sinensis and Soapberry to replace chemically synthesized surfactants, thereby reducing environmental impact and safety risks; (2) The present invention uses ultrasound-assisted saponin natural surfactant to emulsify kerosene, which reduces the particle size of kerosene droplets, increases the collision probability between kerosene and graphite particles, reduces the amount of polar collectors such as kerosene and diesel, and effectively reduces production costs; (2) The process of the present invention is simple and easy to operate. Ultrasonic physical strengthening further reduces the oil droplet size of the emulsified kerosene, and enables the emulsified kerosene microemulsion to exist stably for a long time, thereby improving the flotation rate of microcrystalline graphite. (3) The recovery rate of the microcrystalline graphite product treated by the method of the present invention is greatly improved, reaching more than 87%, meeting the needs of subsequent graphite ore concentration. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the SEM image of the microcrystalline graphite ore used in Example 3; Figure 2 This is the SEM image of the microcrystalline graphite concentrate obtained in Example 3; Figure 3 This is an optical microscope image of the emulsified kerosene obtained after microwave treatment in Example 3.

[0023] like Figure 1 Most of the microcrystalline graphite shown in the figure is black earthy particles, and contains a large amount of non-graphite phase (white part). Due to the characteristics of the microcrystalline structure, impurities will be wrapped inside the graphite grains. However, due to the extremely small diameter of microcrystalline graphite grains, and the dense combination of graphite particles and other minerals and embedded in the clay, it is more difficult to effectively separate microcrystalline graphite from other minerals compared to flake graphite, resulting in poor floatability.

[0024] Figure 2 Compared to Figure 1 , Figure 2 The medium impurities (white area) are greatly reduced, and most of the remaining area is black graphite, which is consistent with the experimental results. The fixed carbon content is increased and the recovery rate is greatly increased.

[0025] like Figure 3 As shown, the droplets of emulsified kerosene containing saponin extract obtained after microwave treatment (yellow droplets) are uniformly dispersed in water. Although some large droplets are detected, most of them are small spherical with diameters ranging from 1 to 2µm. The outside is a similar continuous water phase, confirming the water-in-oil (O / W) structure, which is conducive to the full contact between the emulsified kerosene and the microcrystalline graphite. DETAILED DESCRIPTION

[0026] The present invention is further described in detail below in conjunction with specific implementation modes, but the protection scope of the present invention is not limited to the described contents.

[0027] Example 1: A method for flotation of microcrystalline graphite using ultrasonic-assisted anionic and cationic surfactants and emulsified kerosene, the specific steps are as follows: (1) Remove the seeds from the soapberry and place it in a forced air drying oven at 50°C for 24 hours. Grind the dried soapberry peel in a ball mill and sieve it to a particle size of 50 mesh.

[0028] (2) According to the solid-liquid ratio of 1:10, weigh the crushed sapodilla peel and add deionized water to it. Put the mixture solution into a heat-collecting constant temperature heating magnetic stirrer, heat it to 60°C, keep it warm for 2 hours, stir it appropriately during the period, and filter the soaking liquid. Repeat the heating 5 times until the filtrate no longer produces obvious foam, combine the filtrate, and collect the filtrate with a vacuum pump.

[0029] (3) The collected filtrate is vacuum concentrated to remove water by evaporation. The heating method is steam heating at a temperature of 40°C and a vacuum degree of 0.1 atm for 3 hours to obtain a concentrated saponin extract.

[0030] (4) Add 10 times the volume of 95% ethanol to the saponin concentrate, place the dissolved solution in a centrifuge at a speed of 4000 r / min for 10 min, take the supernatant and distill it under reduced pressure to recover the ethanol. Repeat the purification three times to obtain a light yellow saponin viscous liquid and a relatively pure saponin component.

[0031] (5) Add 2% of the total volume of kerosene saponin natural surfactant (i.e., the light yellow saponin viscous liquid obtained in the previous step) to kerosene, heat in a water bath at 55°C, stir at a rate of 1000 rpm, and prepare a kerosene microemulsion for 5 min.

[0032] (6) The obtained microemulsion was subjected to ultrasonic treatment in an intelligent numerically controlled ultrasonic generator at an ultrasonic power of 10 W, a frequency of 20 kHz, and a time of 5 min to obtain a stable emulsified kerosene; (7) Grind the natural microcrystalline graphite ore with a fixed carbon content of 40% with a vibration mill for 3 minutes to obtain microcrystalline graphite ore with a particle size of -200 mesh accounting for more than 95%, and then mix the graphite ore with water at a slurry concentration of 7% for 3 minutes to obtain a slurry, and add Na 2 CO 3 Adjust the pH of the slurry to 8 and continue stirring for 3 minutes. Add 1500g / t of sodium silicate inhibitor (stir for 3 minutes), 1000g / t of emulsified kerosene collector (stir for 3 minutes), and 250g / t of MIBC foaming agent (stir for 3 minutes) in order. Then turn on the aeration switch (the air intake is 16L / h), scrape and foam for 5 minutes, filter the scraped foam and dry it at 80℃ to obtain microcrystalline graphite concentrate.

[0033] The yield of saponin obtained in this embodiment is 39.1% (19.55 / 50g), the fixed carbon content of microcrystalline graphite concentrate is 73.52%, the recovery rate is 86.3%, and the scraping time is 5min.

[0034] Example 2: A method for enhancing the flotation of microcrystalline graphite using biomass derivatives, the specific steps are as follows: (1) Remove the seeds from the soapberry and place it in a forced air drying oven at 50°C for 24 hours. Grind the dried soapberry peel in a ball mill and sieve it to a particle size of 50 mesh.

[0035] (2) According to the solid-liquid ratio of 1:15, weigh the crushed sapodilla peel and add deionized water to it. Put the mixture solution into a heat-collecting constant temperature heating magnetic stirrer, heat it to 65°C, keep it warm for 3 hours, stir it appropriately during the period, and filter the soaking liquid. Repeat the heating 5 times until the filtrate no longer produces obvious foam, combine the filtrate, and collect the filtrate by vacuum filtration.

[0036] (3) The collected filtrate is vacuum concentrated to remove water by evaporation. The heating method is steam heating at a temperature of 45°C and a vacuum degree of 0.2 atm for 1 hour to obtain a concentrated saponin extract.

[0037] (4) Add 10 times the volume of 95% ethanol to the saponin concentrate, place the dissolved solution in a centrifuge at a speed of 4000 rmin for 10 min, take the supernatant and distill under reduced pressure to recover ethanol. Repeat the purification three times to obtain a light yellow saponin viscous liquid and a relatively pure saponin component.

[0038] (5) Add 4% of the total amount of kerosene saponin natural surfactant (i.e., the light yellow saponin viscous liquid obtained in the previous step) to kerosene, heat in a water bath at 55°C, stir at a rate of 1000 rpm, and prepare a kerosene microemulsion for 5 min.

[0039] (6) The obtained microemulsion was subjected to ultrasonic treatment in an intelligent numerically controlled ultrasonic generator at an ultrasonic power of 20 W, a frequency of 20 kHz, and a time of 5 min to obtain a stable emulsified kerosene; (7) Grind the natural microcrystalline graphite ore with a fixed carbon content of 45% with a vibration mill for 3 minutes to obtain microcrystalline graphite ore with a particle size of -200 mesh accounting for more than 95%, and then mix the graphite ore with water at a ratio of 8% slurry concentration for 3 minutes to obtain a slurry, and add Na 2 CO 3 Adjust the pH of the slurry to 9 and continue stirring for 3 minutes. Add 1600g / t of sodium silicate inhibitor (stir for 3 minutes), 1200g / t of emulsified kerosene collector (stir for 3 minutes), and 350g / t of MIBC foaming agent (stir for 3 minutes) in order. Then turn on the aeration switch (the air intake is 20L / h), scrape and foam for 5 minutes, filter the scraped foam and dry it at 80℃ to obtain microcrystalline graphite concentrate.

[0040] The yield of saponin obtained in this embodiment is 42.5% (21.25 / 50g), the fixed carbon content of microcrystalline graphite concentrate is 74.37%, the recovery rate is 87.8%, and the scraping time is 5min.

[0041] Example 3: A method for enhancing the flotation of microcrystalline graphite using biomass derivatives, the specific steps are as follows: (1) Remove the seeds from the soapberry and place it in a forced air drying oven at 50°C for 24 hours. Grind the dried soapberry peel in a ball mill and sieve it to a particle size of 50 mesh.

[0042] (2) According to the solid-liquid ratio of 1:20, weigh the crushed sapodilla peel and add deionized water to it. Put the mixture solution into a heat-collecting constant temperature heating magnetic stirrer, heat it to 70°C, keep it warm for 4 hours, stir it appropriately during the period, and filter the soaking liquid. Repeat the heating 5 times until the filtrate no longer produces obvious foam, combine the filtrate, and collect the filtrate by vacuum filtration.

[0043] (3) The collected filtrate is vacuum concentrated to remove water by evaporation. The heating method is steam heating at a temperature of 55°C and a vacuum degree of 0.3 atm for 3 hours to obtain a concentrated saponin extract.

[0044] (4) Add 10 times the volume of 95% ethanol to the saponin concentrate, place the dissolved solution in a centrifuge at a speed of 4000 r / min for 10 min, take the supernatant and distill it under reduced pressure to recover the ethanol. Repeat the purification three times to obtain a light yellow saponin viscous liquid and a relatively pure saponin component.

[0045] (5) Add 6% of the total amount of kerosene saponin natural surfactant (i.e., the light yellow saponin viscous liquid obtained in the previous step) to kerosene, heat in a water bath at 55°C, stir at a rate of 1000 rpm, and prepare a kerosene microemulsion for 5 min.

[0046] (6) The obtained microemulsion was subjected to ultrasonic treatment in an intelligent numerically controlled ultrasonic generator at an ultrasonic power of 30 W, a frequency of 20 kHz, and a time of 5 min to obtain a stable emulsified kerosene; (7) Grind the natural microcrystalline graphite ore with a fixed carbon content of 50% with a vibration mill for 3 minutes to obtain microcrystalline graphite ore with a particle size of -200 mesh accounting for more than 95%, and then mix the graphite ore with water at a pulp concentration of 9% for 3 minutes to obtain a pulp, and add CaO to adjust the pulp pH to 9, and continue stirring for 3 minutes. Add inhibitor sodium silicate 1700g / t (stirring for 3 minutes), collector emulsified kerosene 1400g / t (stirring for 3 minutes), and foaming agent MIBC 450g / t (stirring for 3 minutes) in order according to the dosage. Then turn on the inflation switch (air intake volume is 24L / h), scrape and foam for 3 minutes, filter the scraped foam and dry it at 80℃ to obtain microcrystalline graphite concentrate.

[0047] The yield of Gleditsia saponin obtained in this embodiment is 45.2% (22.6 / 50g), the fixed carbon content of the obtained microcrystalline graphite concentrate is 74.59%, the recovery rate is 88.2%, and the scraping time is 3min.

[0048] Example 4: A method for enhancing the flotation of microcrystalline graphite using biomass derivatives, the specific steps are as follows: (1) Remove the seeds from the soapberry and place it in a forced air drying oven at 50°C for 24 hours. Grind the dried soapberry peel in a ball mill and sieve it to a particle size of 50 mesh.

[0049] (2) According to the solid-liquid ratio of 1:15, weigh the crushed sapodilla peel and add deionized water to it. Put the mixture solution into a heat-collecting constant temperature heating magnetic stirrer, heat it to 75°C, keep it warm for 6 hours, stir it appropriately during the period, and filter the soaking liquid. Repeat the heating 5 times until the filtrate no longer produces obvious foam, combine the filtrate, and collect the filtrate by vacuum filtration.

[0050] (3) The collected filtrate is vacuum concentrated to remove water by evaporation. The heating method is steam heating at a temperature of 60°C and a vacuum degree of 0.5 atm for 2 hours to obtain a concentrated saponin extract.

[0051] (4) Add 10 times the volume of 95% ethanol to the saponin concentrate, place the dissolved solution in a centrifuge at a speed of 4000 r / min for 10 min, take the supernatant and distill it under reduced pressure to recover the ethanol. Repeat the purification three times to obtain a light yellow saponin viscous liquid and a relatively pure saponin component.

[0052] (5) Add saponin natural surfactant (i.e., the light yellow saponin viscous liquid obtained in the previous step) in an amount of 10% of the total volume of kerosene to kerosene, heat in a water bath at 55°C, stir at a rate of 1000 rpm, and prepare a kerosene microemulsion for 5 min.

[0053] (6) The obtained microemulsion was subjected to ultrasonic treatment in an intelligent numerically controlled ultrasonic generator at an ultrasonic power of 40 W, a frequency of 20 kHz, and a time of 5 min to obtain a stable emulsified kerosene; (7) Grind the natural microcrystalline graphite ore with a fixed carbon content of 45% with a vibration mill for 3 minutes to obtain microcrystalline graphite ore with a particle size of -200 mesh accounting for more than 95%, and then mix the graphite ore with water at a ratio of 10% of the slurry concentration for 3 minutes to obtain a slurry, and add CaO to adjust the slurry pH to 8, and continue to stir for 3 minutes. Add inhibitor sodium silicate 1800g / t (stirring for 3 minutes), collector emulsified kerosene 1600g / t (stirring for 3 minutes), and foaming agent MIBC 550g / t (stirring for 3 minutes) in order according to the dosage. Then turn on the inflation switch (air intake volume is 28L / h), scrape and foam for 3 minutes, filter the scraped foam and dry it at 80°C to obtain microcrystalline graphite concentrate.

[0054] The yield of Gleditsia saponin obtained in this embodiment is 47.8% (23.9 / 50g), the fixed carbon content of microcrystalline graphite concentrate is 74.25%, the recovery rate is 88.4%, and the scraping time is 3min.

[0055] Example 5: A method for enhancing the flotation of microcrystalline graphite using biomass derivatives, the specific steps are as follows: (1) Take the peel of soapberry, place it in a forced air drying oven at 50°C, keep it warm for 24 hours, grind the dried soapberry peel in a ball mill, and sieve it to a particle size of 50 mesh.

[0056] (2) According to the solid-liquid ratio of 1:10, weigh the crushed soapberry peel and add deionized water to it. Put the mixture solution into a heat-collecting constant temperature heating magnetic stirrer, heat it to 80°C, keep it warm for 2 hours, stir it appropriately during the period, and filter the soaking liquid. Repeat the heating 5 times until the filtrate no longer produces obvious foam, combine the filtrate, and collect the filtrate by vacuum filtration.

[0057] (3) The collected filtrate is vacuum concentrated to remove water by evaporation. The heating method is steam heating at a temperature of 40°C and a vacuum degree of 0.2 atm for 1 hour to obtain a concentrated saponin extract.

[0058] (4) Add 10 times the volume of 95% ethanol to the saponin concentrate, place the dissolved solution in a centrifuge at a speed of 4000 r / min for 10 min, take the supernatant and distill it under reduced pressure to recover the ethanol. Repeat the purification three times to obtain a light yellow saponin viscous liquid and a relatively pure saponin component.

[0059] (5) Add saponin natural surfactant (i.e., the light yellow saponin viscous liquid obtained in the previous step) at a volume ratio of 4% of the total volume of kerosene to kerosene, heat in a water bath at 55°C, stir at a rate of 1000 rpm, and prepare a kerosene microemulsion for 5 min.

[0060] (6) The obtained microemulsion was subjected to ultrasonic treatment in an intelligent numerically controlled ultrasonic generator at an ultrasonic power of 40 W, a frequency of 20 kHz, and a time of 5 min to obtain a stable emulsified kerosene; (7) Grind the natural microcrystalline graphite ore with a fixed carbon content of 55% with a vibration mill for 3 minutes to obtain microcrystalline graphite ore with a particle size of -200 mesh accounting for more than 95%, and then mix the graphite ore with water at a slurry concentration of 11% for 3 minutes to obtain a slurry, and add Na 2 CO 3 Adjust the pH of the slurry to 8 and continue stirring for 3 minutes. Add 1800g / t of sodium silicate inhibitor (stir for 3 minutes), 1900g / t of emulsified kerosene collector (stir for 3 minutes), and 650g / t of MIBC foaming agent (stir for 3 minutes) in order. Then turn on the aeration switch (the air intake is 32L / h), scrape and foam for 3 minutes, filter the scraped foam and dry it at 80℃ to obtain microcrystalline graphite concentrate.

[0061] The yield of soapberry saponin obtained in this embodiment is 36.3% (18.15 / 50g), the fixed carbon content of microcrystalline graphite concentrate is 73.83%, the recovery rate is 87.21%, and the scraping time is 3min.

[0062] Example 6: A method for enhancing the flotation of microcrystalline graphite using biomass derivatives, the specific steps are as follows: (1) Take the peel of soapberry, place it in a forced air drying oven at 50°C, keep it warm for 24 hours, grind the dried soapberry peel in a ball mill, and sieve it to a particle size of 50 mesh.

[0063] (2) According to the solid-liquid ratio of 1:20, weigh the crushed soapberry peel and add deionized water to it. Put the mixture solution into a heat-collecting constant temperature heating magnetic stirrer and heat it to 70°C for 4 hours. Stir it appropriately during the period and filter the soaking liquid. Repeat the heating for 5 times until the filtrate no longer produces obvious foam. Combine the filtrates and collect the filtrate with a vacuum pump.

[0064] (3) The collected filtrate is vacuum concentrated to remove water by evaporation. The heating method is steam heating at a temperature of 50°C and a vacuum degree of 0.4 atm for 3 hours to obtain a concentrated saponin extract.

[0065] (4) Add 10 times the volume of 95% ethanol to the saponin concentrate, place the dissolved solution in a centrifuge at a speed of 4000 r / min for 10 min, take the supernatant and distill it under reduced pressure to recover the ethanol. Repeat the purification three times to obtain a light yellow saponin viscous liquid and a relatively pure saponin component.

[0066] (5) A pale yellow saponin viscous liquid (i.e., saponin natural surfactant) was added to kerosene at a volume of 8% of the total volume of kerosene. The mixture was heated in a water bath at 55°C and stirred at a rate of 1000 rpm for 5 min to obtain a kerosene microemulsion.

[0067] (6) The obtained microemulsion was subjected to ultrasonic treatment in an intelligent numerically controlled ultrasonic generator at an ultrasonic power of 60 W, a frequency of 20 kHz, and a time of 5 min to obtain a stable emulsified kerosene; (7) Grind the natural microcrystalline graphite ore with a fixed carbon content of 60% with a vibration mill for 3 minutes to obtain microcrystalline graphite ore with a particle size of -200 mesh accounting for more than 95%, and then mix the graphite ore with water at a pulp concentration of 8% for 3 minutes to obtain a pulp, and add CaO to adjust the pulp pH to 8, and continue stirring for 3 minutes. Add inhibitor sodium silicate 2000g / t (stirring for 3 minutes), collector emulsified kerosene 2000g / t (stirring for 3 minutes), and foaming agent MIBC 750g / t (stirring for 3 minutes) in order according to the dosage. Then turn on the inflation switch (air intake volume is 24L / h), scrape and foam for 3 minutes, filter the scraped foam and dry it at 80℃ to obtain microcrystalline graphite concentrate.

[0068] The yield of soapberry saponin obtained in this embodiment is 39.4% (19.7 / 50g), the fixed carbon content of microcrystalline graphite concentrate is 72.46%, the recovery rate is 85.37%, and the scraping time is 3min.

[0069] Comparative Example 1: Other conditions are the same as those of Example 4, except that steps 1 to 5 of Example 4 are omitted; that is, the specific steps are as follows: (1) The kerosene is ultrasonically treated in an intelligent numerically controlled ultrasonic generator at an ultrasonic power of 40 W, a frequency of 20 kHz, and a time of 5 min to obtain ultrasonically treated kerosene; (2) Grind the natural microcrystalline graphite ore with a fixed carbon content of 45% with a vibration mill for 3 minutes to obtain microcrystalline graphite ore with a particle size of 200 mesh accounting for more than 95%, and then mix the graphite ore with water at a ratio of 10% of the slurry concentration for 3 minutes to obtain a slurry, and add CaO to adjust the slurry pH to 8, and continue to stir for 3 minutes. Add the inhibitor sodium silicate 1800g / t (stirring for 3 minutes), add ultrasonically treated kerosene at a ratio of 1600g / t (stirring for 3 minutes), and add the foaming agent MIBC550g / t (stirring for 3 minutes). Then turn on the inflation switch (air intake of 20L / h), scrape and foam for 3 minutes, filter the scraped foam and dry it at 80℃ to obtain microcrystalline graphite concentrate.

[0070] The fixed carbon content of the microcrystalline graphite concentrate obtained in this comparative example is 72.68%, and the recovery rate is 81.7%.

[0071] Comparative Example 2: Other conditions are the same as those of Example 4, except that the dosage of the inhibitor is not within the protection range of the present invention of 1500 to 2000 g / t. The specific steps are as follows: (1) Take the peel of soapberry, place it in a forced air drying oven at 50°C, keep it warm for 24 hours, grind the dried soapberry peel in a ball mill, and sieve it to a particle size of 50 mesh.

[0072] (2) According to the solid-liquid ratio of 1:20, weigh the crushed soapberry peel and add deionized water to it. Put the mixture solution into a heat-collecting constant temperature heating magnetic stirrer and heat it to 70°C for 4 hours. Stir it appropriately during the period and filter the soaking liquid. Repeat the heating for 5 times until the filtrate no longer produces obvious foam. Combine the filtrates and collect the filtrate with a vacuum pump.

[0073] (3) The collected saponin aqueous solution is concentrated under vacuum to remove water by evaporation. The heating method is steam heating at a temperature of 55°C and a vacuum degree of 0.3 atm for 2 hours to obtain a concentrated saponin extract.

[0074] (4) Add 10 times the volume of 95% ethanol to the saponin concentrate, place the dissolved solution in a centrifuge at a speed of 4000 r / min for 10 min, take the supernatant and distill it under reduced pressure to recover the ethanol. Repeat the purification three times to obtain a light yellow saponin viscous liquid and a relatively pure saponin component.

[0075] (5) A 6% light yellow saponin viscous liquid (i.e., saponin natural surfactant) was added to kerosene, and the heating temperature in a water bath was 55°C. The stirring speed was 1000 rpm for 5 min to obtain a kerosene microemulsion.

[0076] (6) The obtained microemulsion was subjected to ultrasonic treatment in an intelligent numerically controlled ultrasonic generator at an ultrasonic power of 30 W, a frequency of 20 kHz, and a time of 5 min to obtain a stable emulsified kerosene; (7) Grind the natural microcrystalline graphite ore with a fixed carbon content of 45% with a vibration mill for 3 minutes to obtain microcrystalline graphite ore with a particle size of -200 mesh accounting for more than 95%, and then mix the graphite ore with water at a ratio of 10% of the slurry concentration for 3 minutes to obtain a slurry, and add CaO to adjust the slurry pH to 8, and continue to stir for 3 minutes. Add inhibitor sodium silicate 1000g / t (stirring for 3 minutes), add collector emulsified kerosene 1600g / t (stirring for 3 minutes), and add foaming agent MIBC 550g / t (stirring for 3 minutes) in order according to the dosage. Then turn on the inflation switch (air intake volume is 24L / h), scrape and foam for 7 minutes, filter the scraped foam and dry it at 80℃ to obtain microcrystalline graphite concentrate.

[0077] The yield of Gleditsia saponin obtained in this comparative example is 47.8% (23.9 / 50g), the fixed carbon content of the obtained microcrystalline graphite concentrate is 69.46%, the recovery rate is 84.3%, and the scraping time is 7min.

[0078] Comparative Example 3: Other conditions are the same as those of Example 4, except that the amount of emulsified kerosene (i.e., collector) is not within the protection range of the present invention of 1000 to 2000 g / t. The specific steps are as follows: (1) Take the peel of soapberry, place it in a forced air drying oven at 50°C, keep it warm for 24 hours, grind the dried soapberry peel in a ball mill, and sieve it to a particle size of 50 mesh.

[0079] (2) According to the solid-liquid ratio of 1:20, weigh the crushed soapberry peel and add deionized water to it. Put the mixture solution into a heat-collecting constant temperature heating magnetic stirrer and heat it to 70°C for 4 hours. Stir it appropriately during the period and filter the soaking liquid. Repeat the heating for 5 times until the filtrate no longer produces obvious foam. Combine the filtrates and collect the filtrate with a vacuum pump.

[0080] (3) The collected saponin aqueous solution is concentrated under vacuum to remove water by evaporation. The heating method is steam heating at a temperature of 55°C and a vacuum degree of 0.3 atm for 2 hours to obtain a concentrated saponin extract.

[0081] (4) Add 10 times the volume of 95% ethanol to the saponin concentrate, place the dissolved solution in a centrifuge at a speed of 4000 r / min for 10 min, take the supernatant and distill it under reduced pressure to recover the ethanol. Repeat the purification three times to obtain a light yellow saponin viscous liquid and a relatively pure saponin component.

[0082] (5) A saponin natural surfactant was added to kerosene at a volume ratio of 6% of the total volume of kerosene. The water bath was heated at 55°C and stirred at a rate of 1000 rpm for 5 min to obtain a kerosene microemulsion.

[0083] (6) The obtained microemulsion was subjected to ultrasonic treatment in an intelligent numerically controlled ultrasonic generator at an ultrasonic power of 30 W, a frequency of 20 kHz, and a time of 5 min to obtain a stable emulsified kerosene; (7) Grind the natural microcrystalline graphite ore with a fixed carbon content of 45% with a vibration mill for 3 minutes to obtain microcrystalline graphite ore with a particle size of -200 mesh accounting for more than 95%, and then mix the graphite ore with water at a ratio of 10% of the slurry concentration for 3 minutes to obtain a slurry, and add CaO to adjust the slurry pH to 8, and continue to stir for 3 minutes. Add inhibitor sodium silicate 1800g / t (stirring for 3 minutes), add collector emulsified kerosene 3000g / t (stirring for 3 minutes), and add foaming agent MIBC 550g / t (stirring for 3 minutes) in order according to the dosage. Then turn on the inflation switch (air intake volume is 20L / h), scrape and foam for 3 minutes, filter the scraped foam and dry it at 80°C to obtain microcrystalline graphite concentrate.

[0084] In this comparative example, the yield of saponin from Gleditsia sinensis was 47.8% (23.9 / 50g), the fixed carbon content of the obtained microcrystalline graphite concentrate was 68.3%, the recovery rate was 85.7%, and the scraping time was 3min.

[0085] Comparative Example 4: Other conditions are the same as those of Example 3, except that the amount of the foaming agent is not within the protection range of the present invention, 250 to 750 g / t. The specific steps are as follows: (1) Take the peel of soapberry, place it in a forced air drying oven at 50°C, keep it warm for 24 hours, grind the dried soapberry peel in a ball mill, and sieve it to a particle size of 50 mesh.

[0086] (2) According to the solid-liquid ratio of 1:20, weigh the crushed soapberry peel and add deionized water to it. Put the mixture solution into a heat-collecting constant temperature heating magnetic stirrer and heat it to 70°C for 4 hours. Stir it appropriately during the period and filter the soaking liquid. Repeat the heating for 5 times until the filtrate no longer produces obvious foam. Combine the filtrates and collect the filtrate with a vacuum pump.

[0087] (3) The collected saponin aqueous solution is concentrated under vacuum to remove water by evaporation. The heating method is steam heating at a temperature of 55°C and a vacuum degree of 0.3 atm for 2 hours to obtain a concentrated saponin extract.

[0088] (4) Add 10 times the volume of 95% ethanol to the saponin concentrate, place the dissolved solution in a centrifuge at a speed of 4000 r / min for 10 min, take the supernatant and distill it under reduced pressure to recover the ethanol. Repeat the purification three times to obtain a light yellow saponin viscous liquid and a relatively pure saponin component.

[0089] (5) A saponin natural surfactant was added to kerosene at a volume ratio of 6% of the total volume of kerosene. The water bath was heated at 55°C and stirred at a rate of 1000 rpm for 5 min to obtain a kerosene microemulsion.

[0090] (6) The obtained microemulsion was subjected to ultrasonic treatment in an intelligent numerically controlled ultrasonic generator at an ultrasonic power of 30 W, a frequency of 20 kHz, and a time of 5 min to obtain a stable emulsified kerosene; (7) Grind the natural microcrystalline graphite ore with a fixed carbon content of 45% with a vibration mill for 3 minutes to obtain microcrystalline graphite ore with a particle size of -200 mesh accounting for more than 95%, and then mix the graphite ore with water at a ratio of 10% of the slurry concentration for 3 minutes to obtain a slurry, and add CaO to adjust the slurry pH to 8, and continue to stir for 3 minutes. Add inhibitor sodium silicate 1800g / t (stirring for 3 minutes), add collector emulsified kerosene 1600g / t (stirring for 3 minutes), and add foaming agent MIBC 150g / t (stirring for 3 minutes) in order according to the dosage. Then turn on the inflation switch (air intake volume is 20L / h), scrape and foam for 10 minutes, filter the scraped foam and dry it at 80℃ to obtain microcrystalline graphite concentrate.

[0091] In this comparative example, the yield of Gleditsia saponin is 42.5% (21.25 / 50g), the fixed carbon content of the obtained microcrystalline graphite concentrate is 74.26%, the recovery rate is 79.6%, and the scraping time is 10min.

[0092] Comparative Example 5 Other conditions are the same as those in Example 3, except that: The natural microcrystalline graphite ore with a fixed carbon content of 50% was ground with a vibration mill for 3 minutes to obtain a microcrystalline graphite ore with a particle size of -200 mesh accounting for more than 95%. Then the graphite ore was mixed with water at a ratio of 9% pulp concentration for 3 minutes to obtain a pulp, and GaO was added to adjust the pulp pH to 9, and the stirring was continued for 3 minutes. According to the dosage, 900g / t of inhibitor water glass (stirring for 3 minutes), 350g / t of collector kerosene (stirring for 3 minutes), and 160g / t of foaming agent MIBC (stirring for 3 minutes) were added in sequence. Then the inflation switch was turned on (the air intake was 20L / h), and the foam was scraped for 3 minutes. The scraped foam was filtered and dried at 80°C to obtain the microcrystalline graphite concentrate.

[0093] The fixed carbon content of the obtained microcrystalline graphite concentrate is only 65.83%, and the recovery rate is only 74.2%.

[0094] The specific implementation modes of the present invention are described in detail above, but the present invention is not limited to the above implementation modes, and various changes can be made within the knowledge scope of ordinary technicians in this field without departing from the purpose of the present invention.

Claims

1. A method for enhancing the flotation of microcrystalline graphite using biomass derivatives, characterized in that: The steps include: The microcrystalline graphite powder raw material is mixed with water to obtain a pulp solution, and a pH adjuster is added to adjust the pH value of the pulp to 8-9; then an inhibitor, a collector, and a frother are added to perform aeration and frothing flotation to obtain a primary roughing concentrate; the collector is emulsified kerosene containing a biomass derivative; the biomass derivative contains a saponin extract; During flotation, the dosage of the depressant is 1500-2000 g / t, the dosage of the collector is 1000-2000 g / t, and the dosage of the frother is 250-750 g / t.

2. The method for enhancing the flotation of microcrystalline graphite using biomass derivatives according to claim 1, characterized in that: The saponin extract is obtained by the following process; Step 1 The biomass is placed in a drying oven for drying, and then crushed and sieved; the biomass is selected from at least one of Gleditsia sinensis and Soapberry; Step 2 Weigh the powder obtained in step 1, add it to water, and stir at 60°C to 80°C for at least 2 hours; filter; and collect the filtrate; Step 3 The filtrate collected in step 2 is concentrated under vacuum to evaporate water to obtain a concentrated saponin extract; during vacuum concentration, the heating temperature is less than or equal to 60° C. and the vacuum degree is 0.1 to 0.5 atm; Step 4 Add ethanol to the saponin concentrated extract obtained in step 3, and place the dissolved solution in a centrifuge for centrifugation to obtain a light yellow saponin viscous liquid.

3. The method for enhancing the flotation of microcrystalline graphite using biomass derivatives according to claim 2, characterized in that: The peel of soapberry is taken, and the core of Gleditsia sinensis is removed to take only the shell; the peel and / or core obtained are placed in a drying oven at 45-55° C. and dried for at least 12 hours, preferably 20-28 hours; the dried biomass is placed in a ball mill and ground, passed through a 50-mesh sieve, and the sieve residue is taken.

4. The method for enhancing the flotation of microcrystalline graphite using biomass derivatives according to claim 2, characterized in that: According to the mass ratio of powder: water = 1: 8-25, preferably 1: 10-20, the powder obtained in step 1 is added to water and stirred at 60° C. to 80° C. for 2-6 hours.

5. The method for enhancing the flotation of microcrystalline graphite using biomass derivatives according to claim 2, characterized in that: During vacuum concentration in step 3, the heating method is steam heating, the heating temperature is 40°C to 60°C, the vacuum degree is 0.1 to 0.5 atm, and the concentration time is 1 to 3 hours.

6. The method for enhancing the flotation of microcrystalline graphite using biomass derivatives according to claim 2, characterized in that: In step 4, 5 to 15 times, preferably 8 to 12 times, volume of 90 to 95% ethanol is added to the saponin concentrate, the dissolved solution is placed in a centrifuge at a speed of 3000 to 5000 r / min, preferably 3500 to 4500 r / min, centrifuged for at least 8 minutes, preferably 8 to 15 minutes, the supernatant is taken and the ethanol is recovered by vacuum distillation, the operation is repeated at least 2 times, preferably 3 times, to obtain a light yellow saponin viscous liquid, and a relatively pure saponin component is obtained.

7. The method for enhancing the flotation of microcrystalline graphite using biomass derivatives according to claim 2, characterized in that: The saponin viscous liquid obtained in step 4 is heated and mixed with kerosene in a water bath to obtain a kerosene microemulsion, and the kerosene microemulsion is emulsified by ultrasound to obtain a stable emulsified kerosene as a collector for subsequent microcrystalline graphite flotation; The addition amount of the light yellow saponin viscous liquid is between 1% and 10% of the total volume of kerosene, the water bath heating temperature is 50-60°C, the stirring speed is 800-1200r / min, the time is 4-6min, and kerosene microemulsion is obtained. When ultrasonic emulsification is used for kerosene microemulsion, the ultrasonic power is 10 to 60 W, and the ultrasonic emulsification treatment time is 5 to 10 minutes.

8. The method for enhancing the flotation of microcrystalline graphite using biomass derivatives according to claim 1, characterized in that: The fixed carbon content of the microcrystalline graphite ore is 35% to 60%; the microcrystalline graphite powder with a particle size of -200 mesh accounts for more than 95% of the total volume of the microcrystalline graphite powder raw material.

9. The method for enhancing the flotation of microcrystalline graphite using biomass derivatives according to claim 1, characterized in that: The concentration of the slurry solution is 7 wt.% to 11 wt.%. After adding pH adjusters CaO and / or Na2CO3, the pH of the slurry is adjusted to 8 to 9.

10. The method for enhancing the flotation of microcrystalline graphite using biomass derivatives according to claim 7, characterized in that: During flotation, the dosage of the depressant is 1500-1800 g / t; the dosage of the collector is 1000-1900 g / t, more preferably 1000-1600 g / t, and the dosage of the frother is 250-650 g / t; The inhibitor is selected from at least one of sodium silicate, water glass and sodium carboxymethyl cellulose; The collector is emulsified kerosene containing saponin extract; The foaming agent is selected from at least one of methyl isobutyl carbinol, sec-octanol and terpineol.

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