Preparation method of high-whiteness light calcium carbonate

Abstract

The invention relates to the technical field of calcium carbonate manufacturing, in particular to a preparation method of high-whiteness light calcium carbonate. Comprising the following steps: efficiently leaching the calcium element in the carbide slag; preparing a microbial crystal form control agent; and carrying out electric dispersion treatment and precipitation on calcium ions. The microbial crystal form control agent is prepared by regulating and controlling the mixing ratio of the bacillus pumilus fermentation liquor to the pseudomonas fluorescens fermentation liquor, and it is avoided that in the full mixing process of the microbial crystal form control agent and the calcium-containing filtrate, Ca < 2 + > is mineralized to form large calcium carbonate particles; stearic acid and sodium polyacrylate in the microbial crystal form control agent can enable particles to be more stable, provide ion adsorption capacity, optimize the crystal form of calcium carbonate and form vaterite type crystals with smaller crystal form, and bacillus pumilus can assist generation of small-particle-size calcium carbonate along with time, so that high-whiteness small-particle-size light calcium carbonate is obtained.

Description

Technical Field

[0001] The invention relates to the technical field of calcium carbonate manufacturing, and in particular to a method for preparing high-whiteness light calcium carbonate. Background Art

[0002] Calcium carbonate is an important inorganic chemical raw material, widely used in rubber, plastic, ink and other industries. It is low-priced and abundant in source. According to different production processes, calcium carbonate powder is mainly divided into two types: one is heavy calcium carbonate (GCC) obtained by crushing and grinding natural calcium carbonate (such as marble, shells, etc.), and the other is light calcium carbonate synthesized by chemical reaction of materials such as phosphogypsum and carbide slag in liquid. The production process of heavy calcium carbonate is relatively simple, but due to its high impurities and large particle size, it is usually less used in the field of fine chemicals, while light calcium carbonate is often used in the field of fine chemicals.

[0003] Light calcium carbonate is currently generally prepared by carbonization. First, limestone, carbide slag and other materials are processed to obtain calcium oxide, which is further digested and separated to obtain a solution containing calcium ions. Carbon dioxide gas is then introduced to obtain calcium carbonate slurry, and then solid-liquid separation is performed to obtain light calcium carbonate. In order to obtain calcium carbonate with smaller and more uniform particle size, many processes will add additives to the calcium ion-containing solution. These additives include mineralizing microbial additives. Although mineralizing microbial additives can assist CO2 in the rapid formation of calcium carbonate grains, in order to better assist CO2, mineralizing microorganisms need to be evenly dispersed in the calcium ion-containing solution before CO2 is introduced. This causes the mineralizing microorganisms to mineralize some calcium ions, forming a portion of larger-sized calcium carbonate when the CO2 concentration is not high, affecting the size and uniformity of the subsequent preparation of light calcium carbonate particles. Summary of the invention

[0004] In order to solve the above technical defects, the present invention has developed a method for preparing high-whiteness light calcium carbonate, which can not only make the prepared light calcium carbonate have a fine and uniform particle size, but also have high purity and high whiteness.

[0005] A method for preparing high-whiteness light calcium carbonate comprises the following steps: S1: Efficient leaching of calcium from carbide slag After deionized water and PEG-400 are uniformly mixed, ammonium acetate is slowly added, and after the ammonium acetate is completely dissolved, ethanol is added and stirred, the stirring speed is increased and the temperature is raised, and triethyl citrate is added dropwise while stirring, and the stirring is continued to obtain an organic ammonium salt leaching agent, and the powder of calcium carbide slag is added into the preheated organic ammonium salt leaching agent for leaching and suction filtration, and the filter residue is harmlessly treated, and the calcium-containing filtrate is placed in a dark place and sealed for storage for standby use; S2: Preparation of microbial crystal form control agent The method comprises the following steps: activating Bacillus pumilus and oscillating the culture, collecting the bacterial solution and adjusting the concentration, adding mannose to obtain Bacillus pumilus fermentation liquid, activating Pseudomonas fluorescens and oscillating the culture, collecting the bacterial solution and adjusting the concentration to obtain Pseudomonas fluorescens fermentation liquid, dissolving sodium polyacrylate in deionized water, adding barium sulfate and stirring evenly to obtain a sodium polyacrylate solution, melting stearic acid and adding the sodium polyacrylate solution, ultrasonically dispersing the mixture and freeze-drying the mixture, and pulverizing the mixture to obtain a solid powder, and uniformly mixing the Bacillus pumilus fermentation liquid, the Pseudomonas fluorescens fermentation liquid, the solid powder, tricalcium phosphate, sodium citrate and magnesium sulfate in a mass ratio of 1: (0.2-0.3): (0.5-0.6): (0.02-0.025): (0.01-0.02): (0.02-0.03) and storing the mixture at low temperature to obtain a microbial crystal form control agent; S3: Electrodispersion and precipitation of calcium ions The calcium-containing filtrate is placed in a container, stirred continuously with a charged stirring rod, a microbial crystal form control agent is added, pure carbon dioxide is introduced after stirring, and stirring is continued to obtain a suspension, the calcium carbonate precipitate in the suspension is separated, and high-whiteness light calcium carbonate is obtained after washing and drying.

[0006] Furthermore, the efficient leaching of calcium in carbide slag in step S1 comprises the following steps: S1.1: 80-100 parts by weight of deionized water and 0.3-0.4 parts by weight of PEG-400 are placed in a container, and the mixture is continuously stirred at a stirring speed of 300-350 rpm, and then 4-5 parts by weight of ammonium acetate are slowly added, and after the ammonium acetate is completely dissolved, 5-6 parts by weight of ethanol are added, and the stirring is continued for 3-5 minutes, and then the stirring speed is increased to 550-600 rpm and the temperature is raised to 35-40° C., and 0.8-1 parts by weight of triethyl citrate is slowly added dropwise while stirring, and after the addition is completed, the stirring is continued for 10-15 minutes to obtain an organic ammonium salt leaching agent; S1.2: The organic ammonium salt leaching agent prepared in step S1.1 is placed in a container, and the container is placed in a water bath and heated to 30-35°C to obtain a preheated organic ammonium salt leaching agent. 4-5 parts by weight of carbide slag is placed in a ball mill and ground into powder. The powder is sieved through a 120-130 mesh sieve and then added into the preheated organic ammonium salt leaching agent for 25-30 minutes of magnetic stirring. The calcium-containing filtrate and filter residue are then filtered to obtain the calcium-containing filtrate and the filter residue. The filter residue is rendered harmless, and the calcium-containing filtrate is sealed and stored in a dark place for later use.

[0007] Furthermore, the preparation of the microbial crystal form control agent in step S2 comprises the following steps: S2.1: After activating Bacillus pumilus, inoculate it into LB medium and place it in a constant temperature shaker at 37-37.5℃ and 180-200rpm for 22-24 hours. After centrifugation, collect the bacterial solution and adjust the concentration of the bacterial solution to 1×10 8 -3×10 8 CFU / mL, add 0.1-0.2wt% mannose to obtain Bacillus pumilus fermentation broth, activate Pseudomonas fluorescens and inoculate it into LB medium, place it in a constant temperature shaker at 29.5-30℃ and 175-180rpm for 22-24 hours, collect the bacterial solution by centrifugation and adjust the bacterial solution concentration to 1×10 7 -2×10 7 CFU / mL, and the Pseudomonas fluorescens fermentation broth was obtained; S2.2: 5-6 parts by weight of sodium polyacrylate are dissolved in 15-20 parts by weight of deionized water, and then 0.01-0.02 parts by weight of barium sulfate are added and stirred evenly to obtain a sodium polyacrylate solution. 18-20 parts by weight of stearic acid are placed in a container, heated to 70-75°C, and after the stearic acid is completely melted, 20-25 parts by weight of the sodium polyacrylate solution are slowly added within 1-1.5 hours, and ultrasonic dispersion is performed at a frequency of 20-25kHz for 10-12 minutes, followed by freeze drying and pulverization to obtain a solid powder; S2.3: Mix Bacillus pumilus fermentation broth, Pseudomonas fluorescens fermentation broth, solid powder, tricalcium phosphate, sodium citrate and magnesium sulfate in a mass ratio of 1: (0.2-0.3): (0.5-0.6): (0.02-0.025): (0.01-0.02): (0.02-0.03), and then store at 2-4°C to obtain a microbial crystal form controller.

[0008] Furthermore, step S3 of electrodispersion and precipitation of calcium ions comprises the following steps: S3.1: 20-30 parts by weight of the calcium-containing filtrate obtained in step S1.2 is placed in a container, an insulating stirring rod wrapped with copper wire is installed in a stirrer, the two ends of the copper wire are respectively connected to the positive and negative electrodes of the power supply, and the voltage is adjusted to 2-5V, and then placed in the calcium-containing filtrate and stirred continuously at a stirring speed of 200-250rpm, 8-10 parts by weight of a microbial crystal form control agent is added, and pure carbon dioxide is introduced after stirring for 40-50 minutes, the temperature is adjusted to 37-37.5°C, and then stirred continuously at a stirring speed of 80-100rpm until the pH of the calcium-containing filtrate does not change, to obtain a suspension; S3.2: The suspension is placed in a centrifuge for solid-liquid separation to obtain a calcium carbonate precipitate, the calcium carbonate precipitate is washed 2-3 times with anhydrous ethanol, and then dried at 80-85°C to obtain a high-whiteness light calcium carbonate.

[0009] Furthermore, the Pseudomonas fluorescens in step S2.1 is Pseudomonas fluorescens AbⅢ745-6.

[0010] Furthermore, the preparation method of the LB medium in step S2.1 is as follows: by mass fraction, 1% peptone, 0.5% yeast extract and 1% sodium chloride are added to deionized water to prepare 1000 mL of solution, the pH is adjusted to 7 after boiling, and then sterilized at 121° C. for 20 minutes.

[0011] Furthermore, the volume ratio of the pure carbon dioxide introduced in step S3.1 to the calcium-containing filtrate is 1:(1.8-2).

[0012] The beneficial effects are as follows: 1. The present invention performs oscillation culture on Bacillus pumilus and Pseudomonas fluorescens respectively to obtain Bacillus pumilus fermentation liquid and Pseudomonas fluorescens fermentation liquid. At this time, a variety of antibacterial substances, such as anilinomethylacetic acid, are produced in the Pseudomonas fluorescens fermentation liquid due to the metabolism of Pseudomonas fluorescens. The microbial crystal form control agent is obtained by adjusting the mixing ratio of the Bacillus pumilus fermentation liquid and the Pseudomonas fluorescens fermentation liquid, which can inhibit the activity of Bacillus pumilus to a certain extent in the initial stage of adding the calcium-containing filtrate, slow down the mineralization efficiency of Bacillus pumilus, and avoid the microbial crystal form control agent and the calcium-containing filtrate in the process of fully mixing. 2+ The mineralized calcium carbonate particles are larger, which is beneficial to the subsequent formation of small and uniform calcium carbonate particles. After the temperature is raised and CO2 is introduced, the activity of Bacillus pumilus recovers rapidly with time and the number of bacterial colonies, and can assist in the formation of small-particle calcium carbonate. By adjusting the mixed mass ratio of Bacillus pumilus fermentation broth and Pseudomonas fluorescens fermentation broth to 1: (0.2-0.3), not only can the mineralization efficiency of Bacillus pumilus be effectively inhibited in the early stage, but also its activity can be quickly restored in the subsequent stage, thereby obtaining high-purity and high-whiteness small-particle light calcium carbonate.

[0013] 2. The present invention prepares solid powder from stearic acid, barium sulfate and sodium polyacrylate, and then adds the solid powder when preparing a microbial crystal form controller. After the microbial crystal form controller is added to a calcium-containing filtrate and heated and CO2 is introduced, the stearic acid and sodium polyacrylate in the microbial crystal form controller can make the particles more stable, provide ion adsorption capacity, optimize the crystal form of calcium carbonate, and form vaterite-type crystals with smaller crystal forms.

[0014] 3. The present invention prepares an organic ammonium salt leaching agent by mixing deionized water and a surfactant PEG-400, adding ammonium acetate, and then dripping triethyl citrate. When the organic ammonium salt leaching agent is used to leach calcium ions from carbide slag, acetate ions and calcium ions generate soluble calcium acetate, while triethyl citrate can form a stable chelate with calcium ions to reduce the concentration of calcium ions. The synergy of the two can effectively increase the speed and depth of acetate ions invading the interior of the carbide slag, thereby increasing the leaching rate of calcium ions.

[0015] 4. The present invention stirs the calcium-containing filtrate by a charged stirring rod. Compared with the ordinary stirring process, it can fully drive the ions in the solution to move, avoid the deposition and aggregation of calcium carbonate to form large particles, make the crystallization of calcium carbonate more uniform, higher in purity, and form finer crystals. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 The present invention is a flow chart of the method for preparing high-whiteness light calcium carbonate used in the embodiments of the present invention. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0018] Example 1 A method for preparing high-whiteness light calcium carbonate, such as Figure 1 As shown, the following steps are included: S1: Efficient leaching of calcium from carbide slag S1.1: 80 parts by weight of deionized water and 0.3 parts by weight of PEG-400 are placed in a container, and the mixture is continuously stirred at a stirring speed of 300 rpm. Then, 4 parts by weight of ammonium acetate are slowly added. After the ammonium acetate is completely dissolved, 5 parts by weight of ethanol are added, and the stirring is continued for 3 minutes. Then, the stirring speed is increased to 550 rpm and the temperature is raised to 35° C., and 0.8 parts by weight of triethyl citrate is slowly added dropwise while stirring. After the addition is completed, the stirring is continued for 10 minutes to obtain an organic ammonium salt leaching agent; S1.2: The organic ammonium salt leaching agent prepared in step S1.1 is placed in a container, and the container is placed in a water bath and heated to 30°C to obtain a preheated organic ammonium salt leaching agent. 4 parts by weight of carbide slag is placed in a ball mill and ground into powder. After passing through a 120-mesh sieve, the powder is added into the preheated organic ammonium salt leaching agent and magnetic stirring is performed for 25 minutes. The calcium-containing filtrate and filter residue are then filtered to obtain the calcium-containing filtrate and the filter residue. The filter residue is rendered harmless, and the calcium-containing filtrate is placed in a sealed place in the dark for storage.

[0019] S2: Preparation of microbial crystal form control agent S2.1: After activating Bacillus pumilus, inoculate it into LB medium. The LB medium is prepared by adding 1% peptone, 0.5% yeast extract and 1% sodium chloride by mass fraction into deionized water to make a 1000mL solution. After boiling, adjust the pH to 7, and then sterilize it at 121℃ for 20 minutes. Place it in a constant temperature shaker at 37℃ and 180rpm for 22 hours. After centrifugation, collect the bacterial solution and adjust the concentration of the bacterial solution to 1×10 8 CFU / mL, 0.1wt% mannose was added to obtain Bacillus pumilus fermentation broth, and Pseudomonas fluorescens AbⅢ745-6 was activated and inoculated into LB medium, and placed in a constant temperature shaker at 29.5℃ and 175rpm for 22 hours. The bacterial solution was collected by centrifugation and the concentration of the bacterial solution was adjusted to 1×10 7 CFU / mL, and the Pseudomonas fluorescens fermentation broth was obtained; S2.2: 5 parts by weight of sodium polyacrylate are dissolved in 15 parts by weight of deionized water, and then 0.01 parts by weight of barium sulfate are added and stirred to obtain a sodium polyacrylate solution. 18 parts by weight of stearic acid are placed in a container and heated to 70°C. After the stearic acid is completely melted, 20 parts by weight of the sodium polyacrylate solution are slowly added within 1 hour. Ultrasonic dispersion is performed at a frequency of 20 kHz for 10 minutes, and then freeze-dried and pulverized to obtain a solid powder. S2.3: Evenly mix the Bacillus pumilus fermentation broth, Pseudomonas fluorescens fermentation broth, solid powder, tricalcium phosphate, sodium citrate and magnesium sulfate in a mass ratio of 1:0.2:0.5:0.02:0.01:0.02, and then store at 2°C to obtain a microbial crystal form controller.

[0020] S3: Electrodispersion and precipitation of calcium ions S3.1: Take 20 parts by weight of the calcium-containing filtrate obtained in step S1.2 and place it in a container. Install an insulated stirring rod wrapped with copper wire in a stirrer. Connect the two ends of the copper wire to the positive and negative electrodes of a power supply, respectively. Adjust the voltage to 2V. Then place it in the calcium-containing filtrate and continue stirring at a stirring speed of 200rpm. Add 8 parts by weight of a microbial crystal form control agent. After stirring for 40 minutes, introduce pure carbon dioxide. The volume ratio of pure carbon dioxide to calcium-containing filtrate is 1:1.8. Adjust the temperature to 37°C. Then continue stirring at a stirring speed of 80rpm until the pH of the calcium-containing filtrate does not change to obtain a suspension. S3.2: The suspension is placed in a centrifuge for solid-liquid separation to obtain a calcium carbonate precipitate, the calcium carbonate precipitate is washed twice with anhydrous ethanol, and then dried at 80° C. to obtain a high-whiteness light calcium carbonate.

[0021] Example 2 A method for preparing high-whiteness light calcium carbonate, such as Figure 1 As shown, the following steps are included: S1: Efficient leaching of calcium from carbide slag S1.1: 100 parts by weight of deionized water and 0.4 parts by weight of PEG-400 are placed in a container, and the mixture is continuously stirred at a stirring speed of 300 rpm, and then 5 parts by weight of ammonium acetate are slowly added, and after the ammonium acetate is completely dissolved, 6 parts by weight of ethanol are added, and the stirring is continued for 3 minutes, and then the stirring speed is increased to 550 rpm and the temperature is raised to 35° C., and 1 part by weight of triethyl citrate is slowly added dropwise while stirring, and after the addition is completed, the stirring is continued for 10 minutes to obtain an organic ammonium salt leaching agent; S1.2: The organic ammonium salt leaching agent obtained in step S1.1 is placed in a container, and the container is placed in a water bath and heated to 30°C to obtain a preheated organic ammonium salt leaching agent. 5 parts by weight of carbide slag is placed in a ball mill and ground into powder. The powder is sieved through a 120-mesh sieve and then added into the preheated organic ammonium salt leaching agent for 25 minutes of magnetic stirring. The calcium-containing filtrate and filter residue are then filtered to obtain the calcium-containing filtrate and the filter residue. The filter residue is rendered harmless, and the calcium-containing filtrate is sealed and stored in a dark place for later use.

[0022] S2: Preparation of microbial crystal form control agent S2.1: After activating Bacillus pumilus, inoculate it into LB medium. The LB medium is prepared by adding 1% peptone, 0.5% yeast extract and 1% sodium chloride by mass fraction into deionized water to make a 1000mL solution. After boiling, adjust the pH to 7, and then sterilize it at 121℃ for 20 minutes. Place it in a constant temperature shaker at 37℃ and 180rpm for 22 hours. After centrifugation, collect the bacterial solution and adjust the concentration of the bacterial solution to 1×10 8 CFU / mL, 0.2wt% mannose was added to obtain Bacillus pumilus fermentation broth, and Pseudomonas fluorescens AbⅢ745-6 was activated and inoculated into LB medium, and placed in a constant temperature shaker at 29.5℃ and 175rpm for 22 hours. The bacterial solution was collected by centrifugation and the concentration of the bacterial solution was adjusted to 1×10 7 CFU / mL, and the Pseudomonas fluorescens fermentation broth was obtained; S2.2: 6 parts by weight of sodium polyacrylate are dissolved in 20 parts by weight of deionized water, and then 0.02 parts by weight of barium sulfate are added and stirred to obtain a sodium polyacrylate solution. 20 parts by weight of stearic acid are placed in a container and heated to 70°C. After the stearic acid is completely melted, 25 parts by weight of the sodium polyacrylate solution are slowly added within 1 hour. Ultrasonic dispersion is performed at a frequency of 20 kHz for 12 minutes, and then freeze-dried and pulverized to obtain a solid powder. S2.3: Evenly mix the Bacillus pumilus fermentation broth, Pseudomonas fluorescens fermentation broth, solid powder, tricalcium phosphate, sodium citrate and magnesium sulfate in a mass ratio of 1:0.3:0.6:0.025:0.02:0.03, and then store at 2°C to obtain a microbial crystal form controller.

[0023] S3: Electrodispersion and precipitation of calcium ions S3.1: 30 parts by weight of the calcium-containing filtrate obtained in step S1.2 is placed in a container, an insulated stirring rod wrapped with copper wire is installed in a stirrer, the two ends of the copper wire are respectively connected to the positive and negative electrodes of the power supply, and the voltage is adjusted to 2V, and then placed in the calcium-containing filtrate and stirred continuously at a stirring speed of 200rpm, 10 parts by weight of a microbial crystal form control agent is added, and pure carbon dioxide is introduced after stirring for 40 minutes, the volume ratio of pure carbon dioxide to calcium-containing filtrate is 1:1.8, the temperature is adjusted to 37°C, and then stirred continuously at a stirring speed of 80rpm until the pH of the calcium-containing filtrate does not change, to obtain a suspension; S3.2: The suspension is placed in a centrifuge for solid-liquid separation to obtain a calcium carbonate precipitate, the calcium carbonate precipitate is washed twice with anhydrous ethanol, and then dried at 80° C. to obtain a high-whiteness light calcium carbonate.

[0024] Example 3 A method for preparing high-whiteness light calcium carbonate, such as Figure 1 As shown, the following steps are included: S1: Efficient leaching of calcium from carbide slag S1.1: 80 parts by weight of deionized water and 0.3 parts by weight of PEG-400 are placed in a container, and the mixture is continuously stirred at a stirring speed of 350 rpm, and then 4 parts by weight of ammonium acetate are slowly added, and after the ammonium acetate is completely dissolved, 5 parts by weight of ethanol are added, and the stirring is continued for 5 minutes, and then the stirring speed is increased to 600 rpm and the temperature is raised to 40° C., and 0.8 parts by weight of triethyl citrate is slowly added dropwise while stirring, and after the addition is completed, the stirring is continued for 15 minutes to obtain an organic ammonium salt leaching agent; S1.2: The organic ammonium salt leaching agent prepared in step S1.1 is placed in a container, and the container is placed in a water bath and heated to 35°C to obtain a preheated organic ammonium salt leaching agent. 4 parts by weight of carbide slag is placed in a ball mill and ground into powder. The powder is sieved through a 130-mesh sieve and then added into the preheated organic ammonium salt leaching agent for 30 minutes of magnetic stirring. The calcium-containing filtrate and filter residue are then filtered to obtain the calcium-containing filtrate and the filter residue. The filter residue is rendered harmless, and the calcium-containing filtrate is sealed and stored in a dark place for later use.

[0025] S2: Preparation of microbial crystal form control agent S2.1: After activating Bacillus pumilus, inoculate it into LB medium. The LB medium is prepared by adding 1% peptone, 0.5% yeast extract and 1% sodium chloride by mass fraction into deionized water to make 1000mL solution, boil it and adjust the pH to 7, then sterilize it at 121℃ for 20 minutes, and culture it in a constant temperature shaker at 37.5℃ and 200rpm for 24 hours. After centrifugation, the bacterial solution is adjusted to a concentration of 3×10 8 CFU / mL, 0.1wt% mannose was added to obtain Bacillus pumilus fermentation broth, and Pseudomonas fluorescens AbⅢ745-6 was activated and inoculated into LB medium, and placed in a constant temperature shaker at 30℃ and 180rpm for 24 hours. The bacterial solution was collected by centrifugation and the concentration of the bacterial solution was adjusted to 2×10 7 CFU / mL, and the Pseudomonas fluorescens fermentation broth was obtained; S2.2: 5 parts by weight of sodium polyacrylate are dissolved in 15 parts by weight of deionized water, and then 0.01 parts by weight of barium sulfate are added and stirred to obtain a sodium polyacrylate solution. 18 parts by weight of stearic acid are placed in a container and heated to 75°C. After the stearic acid is completely melted, 20 parts by weight of the sodium polyacrylate solution are slowly added within 1.5 hours. Ultrasonic dispersion is performed at a frequency of 25 kHz for 12 minutes, and then freeze-dried and pulverized to obtain a solid powder. S2.3: Evenly mix the Bacillus pumilus fermentation broth, Pseudomonas fluorescens fermentation broth, solid powder, tricalcium phosphate, sodium citrate and magnesium sulfate in a mass ratio of 1:0.25:0.5:0.02:0.01:0.02, and then store at 4°C to obtain a microbial crystal form controller.

[0026] S3: Electrodispersion and precipitation of calcium ions S3.1: Take 20 parts by weight of the calcium-containing filtrate obtained in step S1.2 and place it in a container. Install an insulated stirring rod wrapped with copper wire in a stirrer. Connect the two ends of the copper wire to the positive and negative electrodes of a power supply, respectively. Adjust the voltage to 5V. Then place it in the calcium-containing filtrate and continue stirring at a stirring speed of 250rpm. Add 8 parts by weight of a microbial crystal form control agent. After stirring for 50 minutes, introduce pure carbon dioxide. The volume ratio of pure carbon dioxide to calcium-containing filtrate is 1:2. Adjust the temperature to 37.5°C. Then continue stirring at a stirring speed of 100rpm until the pH of the calcium-containing filtrate does not change to obtain a suspension. S3.2: The suspension is placed in a centrifuge for solid-liquid separation to obtain a calcium carbonate precipitate, the calcium carbonate precipitate is washed three times with anhydrous ethanol, and then dried at 85°C to obtain a high-whiteness light calcium carbonate.

[0027] Comparative Example 1 Compared with Example 1, the difference of Comparative Example 1 is that in Comparative Example 1, Pseudomonas fluorescens fermentation broth is not added in step S2.3 to obtain a microbial crystal form control agent, and the remaining steps are the same as those in Example 1. The obtained high-whiteness light calcium carbonate is recorded as Comparative Example 1.

[0028] Comparative Example 2 Compared with Example 1, the difference of Comparative Example 2 is that step S2.2 is removed in Comparative Example 2, and solid powder is not added in step S2.3 to obtain a microbial crystal form control agent. The remaining steps are the same as those in Example 1, and the obtained high-whiteness light calcium carbonate is recorded as Comparative Example 2.

[0029] Comparative Example 3 Compared with Example 1, the difference of Comparative Example 3 is that in Comparative Example 3, the insulated stirring rod wrapped with copper wire in step S3.1 is replaced by an ordinary stirring rod, and the remaining steps are the same as those in Example 1. The obtained high-whiteness light calcium carbonate is recorded as Comparative Example 3.

[0030] Comparative Example 4 Compared with Example 1, the difference of Comparative Example 4 is that in Comparative Example 4, triethyl citrate is not added in step S1.1 to prepare an ammonium salt leaching agent, the organic ammonium salt leaching agent in step S1.2 is replaced with an ammonium salt leaching agent of equal mass, and the remaining steps are the same as in Example 1.

[0031] Comparative Example 5 Compared with Example 1, the difference of Comparative Example 5 is that in step S2.3, Bacillus pumilus fermentation broth, Pseudomonas fluorescens fermentation broth, solid powder, tricalcium phosphate, sodium citrate and magnesium sulfate are uniformly mixed in a mass ratio of 1:0.1:0.5:0.02:0.01:0.02, and then stored at 2°C to obtain a microbial crystal form controller, and the remaining steps are the same as in Example 1, and the obtained high-whiteness light calcium carbonate is recorded as Comparative Example 5.

[0032] Comparative Example 6 Compared with Example 1, the difference of Comparative Example 6 is that in step S2.3, Bacillus pumilus fermentation broth, Pseudomonas fluorescens fermentation broth, solid powder, tricalcium phosphate, sodium citrate and magnesium sulfate are uniformly mixed in a mass ratio of 1:0.15:0.5:0.02:0.01:0.02, and then stored at 2°C to obtain a microbial crystal form controller, and the remaining steps are the same as in Example 1, and the obtained high-whiteness light calcium carbonate is recorded as Comparative Example 6.

[0033] Comparative Example 7 Compared with Example 1, the difference of Comparative Example 7 is that in step S2.3, Bacillus pumilus fermentation broth, Pseudomonas fluorescens fermentation broth, solid powder, tricalcium phosphate, sodium citrate and magnesium sulfate are uniformly mixed in a mass ratio of 1:0.35:0.5:0.02:0.01:0.02, and then stored at 2°C to obtain a microbial crystal form controller, and the remaining steps are the same as in Example 1, and the obtained high-whiteness light calcium carbonate is recorded as Comparative Example 7.

[0034] Comparative Example 8 Compared with Example 1, the difference of Comparative Example 8 is that in step S2.3, Bacillus pumilus fermentation broth, Pseudomonas fluorescens fermentation broth, solid powder, tricalcium phosphate, sodium citrate and magnesium sulfate are uniformly mixed in a mass ratio of 1:0.4:0.5:0.02:0.01:0.02, and then stored at 2°C to obtain a microbial crystal form controller, and the remaining steps are the same as in Example 1, and the obtained high-whiteness light calcium carbonate is recorded as Comparative Example 8.

[0035] Experiment 1: Take the high-whiteness light calcium carbonate obtained in Examples 1-3, Comparative Examples 1-3 and Comparative Examples 5-8 of equal mass, first measure the whiteness by a digital whiteness meter (XT-48B / BN); then grind the high-whiteness light calcium carbonate into a calcium carbonate powder sample and disperse it in an ethanol solution, place it in an ultrasonic cleaner, ultrasonically disperse it for 5 minutes, select a disposable sizing cuvette method to test the particle size distribution, and test the particle size distribution by a particle size analyzer; then use a thermogravimetric analyzer to test the content of high-whiteness light calcium carbonate, the heating gas atmosphere is air, the heating temperature is 800°C, and the calcium carbonate content is recorded as the purity; record the above whiteness, particle size distribution and purity data and make a table, as shown in Table 1; Table 1: Whiteness, particle size and purity of high whiteness light calcium carbonate

[0036] From the data of Examples 1-3 and Comparative Examples 1-3 in Table 1, it can be seen that the whiteness and purity of the high-whiteness light calcium carbonate prepared in Examples 1-3 are greater than those of Comparative Examples 1-3, and the particle size distribution is smaller than that of Comparative Examples 1-3. It can be proved that adding Pseudomonas fluorescens fermentation broth and solid powder prepared by adding sodium polyacrylate and stearic acid to the microbial crystal form controller, and adding the obtained microbial crystal form controller to the calcium-containing filtrate can not only improve the whiteness and purity of the obtained light calcium carbonate, but also reduce the particle size of the obtained high-whiteness light calcium carbonate. It can also be proved that stirring the calcium-containing filtrate with a charged stirring rod during the carbonization process can fully drive the ions in the solution to move, avoid the deposition and aggregation of calcium carbonate to form large particles, so that the crystallization of calcium carbonate is more uniform, the purity is higher, and the formed crystal form is finer; It can be seen from the data of Examples 1-3 and Comparative Examples 5-8 in Table 1 that when preparing the microbial crystal form controller, when the ratio of Bacillus pumilus fermentation broth to Pseudomonas fluorescens fermentation broth is not in the range of 1: (0.2-0.3), the whiteness and purity of the high-whiteness light calcium carbonate are reduced, and the particle size distribution is also increased. It can be proved that when the ratio of Bacillus pumilus fermentation broth to Pseudomonas fluorescens fermentation broth is in the range of 1: (0.2-0.3), the effect of the microbial crystal form controller is the best, which can not only effectively inhibit the mineralization efficiency of Bacillus pumilus in the early stage, but also quickly restore its activity in the subsequent stage, thereby obtaining high-purity and high-whiteness small-particle light calcium carbonate.

[0037] Experiment 2: Take two portions of carbide slag of equal mass and grind them into powder, perform chemical component analysis on the raw materials by XRF analysis, record the mass m of the carbide slag before leaching, and the mass fraction w of calcium in the carbide slag before leaching, respectively adopt the process of step S1.2 in Example 1 and Comparative Example 4 to perform leaching, obtain filter residue, perform chemical component analysis on the raw materials by XRF analysis, record the mass m1 of the filter residue, and the mass fraction w1 of calcium in the filter residue, and the calcium ion leaching rate = (m·w-m1·w1) / m×100%, perform three parallel experiments, record the calcium ion leaching rate and make a table, as shown in Table 2; Table 2: Calcium ion leaching rate

[0038] It can be seen that the calcium ion leaching rate of Example 1 is greater than that of Comparative Example 4 for three times, which can prove that adding triethyl citrate to ammonium acetate can synergistically leach calcium ions and improve the leaching rate of calcium ions.

[0039] The above embodiments are merely illustrative of the principles and effects of the present invention, and are not intended to limit the present invention. Any person familiar with the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by a person of ordinary skill in the art without departing from the spirit and technical concept disclosed by the present invention shall still be covered by the claims of the present invention.

Claims

1. A method for preparing high-whiteness light calcium carbonate, characterized in that: The following steps are involved: S1: Efficient leaching of calcium from carbide slag After deionized water and PEG-400 are uniformly mixed, ammonium acetate is slowly added, and after the ammonium acetate is completely dissolved, ethanol is added and stirred, the stirring speed is increased and the temperature is raised, and triethyl citrate is added dropwise while stirring, and the stirring is continued to obtain an organic ammonium salt leaching agent, and the powder of calcium carbide slag is added into the preheated organic ammonium salt leaching agent for leaching and suction filtration, and the filter residue is harmlessly treated, and the calcium-containing filtrate is placed in a dark place and sealed for storage for standby use; S2: Preparation of microbial crystal form control agent The method comprises the following steps: activating Bacillus pumilus and oscillating the culture, collecting the bacterial solution and adjusting the concentration, adding mannose to obtain Bacillus pumilus fermentation liquid, activating Pseudomonas fluorescens and oscillating the culture, collecting the bacterial solution and adjusting the concentration to obtain Pseudomonas fluorescens fermentation liquid, dissolving sodium polyacrylate in deionized water, adding barium sulfate and stirring evenly to obtain a sodium polyacrylate solution, melting stearic acid and adding the sodium polyacrylate solution, ultrasonically dispersing the mixture and freeze-drying the mixture, and pulverizing the mixture to obtain a solid powder, and uniformly mixing the Bacillus pumilus fermentation liquid, the Pseudomonas fluorescens fermentation liquid, the solid powder, tricalcium phosphate, sodium citrate and magnesium sulfate in a mass ratio of 1: (0.2-0.3): (0.5-0.6): (0.02-0.025): (0.01-0.02): (0.02-0.03) and storing the mixture at low temperature to obtain a microbial crystal form control agent; S3: Electrodispersion and precipitation of calcium ions The calcium-containing filtrate is placed in a container, stirred continuously with a charged stirring rod, a microbial crystal form control agent is added, pure carbon dioxide is introduced after stirring, and stirring is continued to obtain a suspension, the calcium carbonate precipitate in the suspension is separated, and high-whiteness light calcium carbonate is obtained after washing and drying.

2. The method for preparing a high-whiteness light calcium carbonate according to claim 1, characterized in that: Step S1: Efficient leaching of calcium from carbide slag, comprising the following steps: S1.1: 80-100 parts by weight of deionized water and 0.3-0.4 parts by weight of PEG-400 are placed in a container, and the mixture is continuously stirred at a stirring speed of 300-350 rpm, and then 4-5 parts by weight of ammonium acetate are slowly added, and after the ammonium acetate is completely dissolved, 5-6 parts by weight of ethanol are added, and the stirring is continued for 3-5 minutes, and then the stirring speed is increased to 550-600 rpm and the temperature is raised to 35-40° C., and 0.8-1 parts by weight of triethyl citrate is slowly added dropwise while stirring, and after the addition is completed, the stirring is continued for 10-15 minutes to obtain an organic ammonium salt leaching agent; S1.2: The organic ammonium salt leaching agent prepared in step S1.1 is placed in a container, and the container is placed in a water bath and heated to 30-35°C to obtain a preheated organic ammonium salt leaching agent. 4-5 parts by weight of carbide slag is placed in a ball mill and ground into powder. The powder is sieved through a 120-130 mesh sieve and then added into the preheated organic ammonium salt leaching agent for 25-30 minutes of magnetic stirring. The calcium-containing filtrate and filter residue are then filtered to obtain the calcium-containing filtrate and the filter residue. The filter residue is rendered harmless, and the calcium-containing filtrate is sealed and stored in a dark place for later use.

3. The method for preparing a high-whiteness light calcium carbonate according to claim 1, characterized in that: Step S2: Preparation of a microbial crystal form control agent, comprising the following steps: S2.1: After activating Bacillus pumilus, inoculate it into LB medium and place it in a constant temperature shaker at 37-37.5℃ and 180-200rpm for 22-24 hours. After centrifugation, collect the bacterial solution and adjust the concentration of the bacterial solution to 1×10 8 -3×10 8 CFU / mL, add 0.1-0.2wt% mannose to obtain Bacillus pumilus fermentation broth, activate Pseudomonas fluorescens and inoculate it into LB medium, place it in a constant temperature shaker at 29.5-30℃ and 175-180rpm for 22-24 hours, collect the bacterial solution by centrifugation and adjust the bacterial solution concentration to 1×10 7 -2×10 7 CFU / mL, and the Pseudomonas fluorescens fermentation broth was obtained; S2.2: 5-6 parts by weight of sodium polyacrylate are dissolved in 15-20 parts by weight of deionized water, and then 0.01-0.02 parts by weight of barium sulfate are added and stirred evenly to obtain a sodium polyacrylate solution. 18-20 parts by weight of stearic acid are placed in a container, heated to 70-75°C, and after the stearic acid is completely melted, 20-25 parts by weight of the sodium polyacrylate solution are slowly added within 1-1.5 hours, and ultrasonic dispersion is performed at a frequency of 20-25kHz for 10-12 minutes, followed by freeze drying and pulverization to obtain a solid powder; S2.3: Mix Bacillus pumilus fermentation broth, Pseudomonas fluorescens fermentation broth, solid powder, tricalcium phosphate, sodium citrate and magnesium sulfate in a mass ratio of 1: (0.2-0.3): (0.5-0.6): (0.02-0.025): (0.01-0.02): (0.02-0.03), and then store at 2-4°C to obtain a microbial crystal form controller.

4. The method for preparing a high-whiteness light calcium carbonate according to claim 1, characterized in that: Step S3: electrodispersion and precipitation of calcium ions, comprising the following steps: S3.1: 20-30 parts by weight of the calcium-containing filtrate obtained in step S1.2 is placed in a container, an insulating stirring rod wrapped with copper wire is installed in a stirrer, the two ends of the copper wire are respectively connected to the positive and negative electrodes of the power supply, and the voltage is adjusted to 2-5V, and then placed in the calcium-containing filtrate and stirred continuously at a stirring speed of 200-250rpm, 8-10 parts by weight of a microbial crystal form control agent is added, and pure carbon dioxide is introduced after stirring for 40-50 minutes, the temperature is adjusted to 37-37.5°C, and then stirred continuously at a stirring speed of 80-100rpm until the pH of the calcium-containing filtrate does not change, to obtain a suspension; S3.2: The suspension is placed in a centrifuge for solid-liquid separation to obtain a calcium carbonate precipitate, the calcium carbonate precipitate is washed 2-3 times with anhydrous ethanol, and then dried at 80-85°C to obtain a high-whiteness light calcium carbonate.

5. The method for preparing a high-whiteness light calcium carbonate according to claim 3, characterized in that: The Pseudomonas fluorescens in step S2.1 is Pseudomonas fluorescens AbⅢ745-6.

6. The method for preparing a high-whiteness light calcium carbonate according to claim 3, characterized in that: The preparation method of LB medium in step S2.1 is as follows: by mass fraction, 1% peptone, 0.5% yeast extract and 1% sodium chloride are added to deionized water to prepare 1000 mL of solution, the pH is adjusted to 7 after boiling, and then sterilized at 121°C for 20 minutes.

7. The method for preparing a high-whiteness light calcium carbonate according to claim 4, characterized in that: The volume ratio of the pure carbon dioxide introduced in step S3.1 to the calcium-containing filtrate is 1:(1.8-2).

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