Method for preparing nano calcium carbonate based on alkaline residues

Abstract

The invention discloses a method for preparing nano calcium carbonate based on alkaline residues, which comprises the following steps: (1) grinding an alkaline residue raw material to obtain alkaline residue powder; (2) mixing the alkaline residue powder with a hydrochloric acid solution to obtain an acid leaching solution; (3) adjusting the pH value of the acid leaching solution; (4) mixing the acid leaching solution of which the pH value is adjusted with hexadecyl trimethyl ammonium bromide, n-butyl alcohol and cyclohexane, and uniformly stirring to obtain a microemulsion a; (5) preparing a sodium carbonate solution, mixing the sodium carbonate solution with hexadecyl trimethyl ammonium bromide, n-butyl alcohol and cyclohexane, and uniformly stirring to obtain a microemulsion b; and (6) mixing the microemulsion a and the microemulsion b for reaction, carrying out solid-liquid separation after the reaction is finished, and washing and drying the separated solid-phase product to obtain the nano calcium carbonate. The nano calcium carbonate is prepared by innovatively utilizing effective components in the alkaline residues, so that reduction treatment and resource utilization of the alkaline residues can be realized, and the economic and environment-friendly benefits are remarkable.

Description

Technical Field

[0001] The invention relates to the technical field of industrial solid waste treatment, and in particular to a method for preparing nano calcium carbonate based on alkali residue. Background Art

[0002] Alkali residue is a type of solid waste with huge production volume, which is produced in the process of making alkali by ammonia-soda method. There are a large number of mineral elements (mainly Ca) and strong alkalinity (pH is about 11) in the alkali residue, so it is easy to cause pollution of soil, groundwater and surface water in the disposal and storage site. If it is not properly handled, it will cause serious harm to human health and ecological environment. In order to treat alkali residue and control its pollution environment, the current method includes preparing building materials and desulfurizing agents using alkali residue. For example, the Chinese invention patent with application publication number CN105481303A discloses a kind of unburned brick made based on alkali residue and its preparation method, which is to match alkali residue, fly ash and steel slag to make unburned brick. For example, the Chinese invention patent with application publication number CN118558704A discloses a device and method for preparing flue gas desulfurizer using alkali residue, which can prepare high-quality flue gas desulfurization powder for coal-fired power plants with stock alkali residue. However, the comprehensive utilization rate of alkali residue by the above method is less than 3%, and the consumption of alkali residue is relatively small. Summary of the invention

[0003] Based on the above technical problems, the present invention proposes a method for preparing nano calcium carbonate based on alkali residue, which can achieve the reduction treatment and resource utilization of alkali residue.

[0004] The technical solution adopted by the present invention is:

[0005] A method for preparing nano calcium carbonate based on alkali residue comprises the following steps:

[0006] (1) grinding the alkali residue raw material to obtain alkali residue powder;

[0007] (2) mixing the alkali residue powder and the hydrochloric acid solution to obtain an acid leaching solution;

[0008] (3) adjusting the pH value of the acid leaching solution;

[0009] (4) mixing the pH-adjusted acid leaching solution with hexadecyltrimethylammonium bromide, n-butanol and cyclohexane, and stirring evenly to obtain a microemulsion a;

[0010] (5) preparing a sodium carbonate solution, and mixing the sodium carbonate solution with hexadecyltrimethylammonium bromide, n-butanol and cyclohexane, and stirring uniformly to obtain a microemulsion b;

[0011] (6) mixing the microemulsion a and the microemulsion b to react, performing solid-liquid separation after the reaction, and washing and drying the separated solid phase product to obtain nano calcium carbonate.

[0012] Preferably, in step (1): the alkali residue raw material is alkali residue with a calcium content of more than 30%; the alkali residue raw material is ground to a particle size of less than 0.038 mm, and the portion accounts for ≥70% of the total mass of the alkali residue.

[0013] Preferably, in step (1): before grinding the alkali residue raw material, the alkali residue raw material is crushed and dried; the drying temperature is controlled to be 80-105° C., and the drying time is 24-48 hours.

[0014] Preferably, in step (2): the concentration of the hydrochloric acid solution is 4-5 mol / L, and the mass ratio of the alkali residue powder to the hydrochloric acid solution is 1:3-5.

[0015] Preferably, in step (3): the pH value of the acid leaching solution is adjusted to 11-12 by adding NaOH solution to the acid leaching solution.

[0016] Preferably, in step (4), the acid leaching solution: hexadecyltrimethylammonium bromide: n-butanol: cyclohexane are mixed in a mass ratio of 1:1-3:3-5:5-7.

[0017] Preferably, in step (5): the concentration of the sodium carbonate solution is 0.5-2 mol / L; the sodium carbonate solution: hexadecyltrimethylammonium bromide: n-butanol: cyclohexane are mixed in a mass ratio of 1:1-3:3-5:5-7.

[0018] Preferably, in step (4) and step (5): the mixture is stirred uniformly at room temperature for 50-70 minutes.

[0019] Preferably, in step (6): the reaction is controlled to be carried out at room temperature; solid-liquid separation is performed using a centrifuge; the solid phase product is washed with deionized water and anhydrous ethanol; the drying temperature is 60-80° C., and the drying time is 12-24 h.

[0020] The beneficial technical effects of the present invention are:

[0021] The present invention innovatively utilizes the effective components in the alkali residue to prepare nano calcium carbonate, which can achieve the reduction treatment and resource utilization of the alkali residue, and has significant economic and environmental benefits. Compared with the traditional process for preparing nano calcium carbonate, the present invention uses acid leaching, the reaction between two microemulsions, and the selection of reaction raw materials and dosage, so that the prepared nano calcium carbonate shows advantages in ensuring the uniform particle size and uniform morphology of the product particles. The present invention also has the advantages of short process flow, high efficiency, low energy consumption, and environmental friendliness. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a flow chart of the method for preparing nano calcium carbonate based on alkali residue of the present invention;

[0023] Figure 2 This is a SEM image of the nano calcium carbonate prepared in Example 1 of the present invention;

[0024] Figure 3 This is a SEM image of the nano calcium carbonate prepared in Comparative Example 1 of the present invention;

[0025] Figure 4 This is a SEM image of the nano calcium carbonate prepared in Comparative Example 2 of the present invention. DETAILED DESCRIPTION

[0026] It has been found through research that alkali residue is mainly composed of calcium carbonate and has a high calcium content. How to efficiently utilize the calcium element in alkali residue is the key to realizing the comprehensive utilization of alkali residue. Based on this, the present invention proposes a method for preparing nano calcium carbonate based on alkali residue. This method can not only realize the reduction treatment and resource utilization of alkali residue, but also obtain high-quality nano calcium carbonate through the steps of acid leaching, reaction regulation between two microemulsions, and the selection of reaction raw materials and dosage. The present invention can regulate the particle size of the resultant nano calcium carbonate particles and solve the problem of uneven particle size and morphology of nano calcium carbonate particles.

[0027] The present invention will be further described below in conjunction with specific embodiments.

[0028] Example 1

[0029] like Figure 1 As shown, a method for preparing nano calcium carbonate based on alkali residue comprises the following steps:

[0030] (1) Alkali residue with a calcium content of 30.8% from industrial solid waste is used as the alkali residue raw material. The alkali residue raw material is first crushed, dried at 105°C for 48 hours, and then ground to a particle size of -0.038 mm, which accounts for ≥70% of the total mass of the alkali residue, to obtain alkali residue powder.

[0031] (2) Mixing the alkali residue powder and the hydrochloric acid solution to obtain an acid leaching solution. The concentration of the hydrochloric acid solution is 4.5 mol / L, and the mass ratio of the alkali residue powder to the hydrochloric acid solution is 1:4.

[0032] (3) After the acid leaching solution is mixed evenly, 4 mol / L NaOH solution is added to the acid leaching solution to remove impurities, the pH value of the acid leaching solution is adjusted to 12, and the solution is transferred to a 500 mL wide-mouth bottle.

[0033] (4) The pH-adjusted acid leaching solution was mixed with hexadecyltrimethylammonium bromide, n-butanol and cyclohexane, and stirred evenly at room temperature for 60 minutes to obtain microemulsion a. The mass ratio of acid leaching solution: hexadecyltrimethylammonium bromide: n-butanol: cyclohexane was 1:2:4:6.

[0034] (5) Prepare a 1 mol / L sodium carbonate solution, mix the sodium carbonate solution with hexadecyltrimethylammonium bromide, n-butanol and cyclohexane, and stir evenly at room temperature for 60 min to obtain microemulsion b. The mass ratio of sodium carbonate solution: hexadecyltrimethylammonium bromide: n-butanol: cyclohexane is 1:2:4:6.

[0035] (6) The microemulsion a and the microemulsion b are stirred and mixed at room temperature (25° C.) to react. After the reaction, a centrifuge is used to separate the solid and the liquid. The separated solid phase product is washed with deionized water and anhydrous ethanol, and then dried at 70° C. for 24 hours to obtain nano calcium carbonate.

[0036] Example 2

[0037] A method for preparing nano calcium carbonate based on alkali residue comprises the following steps:

[0038] (1) Alkali slag with a calcium content of more than 30% from industrial solid waste is used as the alkali slag raw material. The alkali slag raw material is first crushed, dried at 80°C for 24 hours, and then ground to a particle size of -0.038 mm, which accounts for ≥70% of the total mass of the alkali slag, to obtain alkali slag powder.

[0039] (2) Mixing the alkali residue powder and the hydrochloric acid solution to obtain an acid leaching solution. The concentration of the hydrochloric acid solution is 4 mol / L, and the mass ratio of the alkali residue powder to the hydrochloric acid solution is 1:5.

[0040] (3) After the acid leaching solution was mixed evenly, 4 mol / L NaOH solution was added to the acid leaching solution to remove impurities, the pH value of the acid leaching solution was adjusted to 11, and the solution was transferred to a 500 mL wide-mouth bottle.

[0041] (4) The pH-adjusted acid leaching solution was mixed with hexadecyltrimethylammonium bromide, n-butanol and cyclohexane, and stirred evenly at room temperature for 50 minutes to obtain microemulsion a. The mass ratio of acid leaching solution: hexadecyltrimethylammonium bromide: n-butanol: cyclohexane was 1:3:3:5.

[0042] (5) Prepare a 2 mol / L sodium carbonate solution, mix the sodium carbonate solution with hexadecyltrimethylammonium bromide, n-butanol and cyclohexane, and stir evenly at room temperature for 50 min to obtain microemulsion b. The mass ratio of sodium carbonate solution: hexadecyltrimethylammonium bromide: n-butanol: cyclohexane is 1:3:3:5.

[0043] (6) The microemulsion a and the microemulsion b are stirred and mixed at room temperature (25° C.) to react. After the reaction, a centrifuge is used to separate the solid and the liquid. The separated solid phase product is washed with deionized water and anhydrous ethanol, and then dried at 60° C. for 20 hours to obtain nano calcium carbonate.

[0044] Example 3

[0045] A method for preparing nano calcium carbonate based on alkali residue comprises the following steps:

[0046] (1) Alkali slag with a calcium content of more than 30% from industrial solid waste is used as the alkali slag raw material. The alkali slag raw material is first crushed, dried at 90°C for 24 hours, and then ground to a particle size of -0.038 mm, which accounts for ≥70% of the total mass of the alkali slag, to obtain alkali slag powder.

[0047] (2) Mixing the alkali residue powder and the hydrochloric acid solution to obtain an acid leaching solution. The concentration of the hydrochloric acid solution is 5 mol / L, and the mass ratio of the alkali residue powder to the hydrochloric acid solution is 1:3.

[0048] (3) After the acid leaching solution is mixed evenly, 4 mol / L NaOH solution is added to the acid leaching solution to adjust the pH value of the acid leaching solution to 12, and the solution is transferred to a 500 mL wide-mouth bottle.

[0049] (4) The pH-adjusted acid leaching solution was mixed with hexadecyltrimethylammonium bromide, n-butanol and cyclohexane, and stirred evenly at room temperature for 70 minutes to obtain microemulsion a. The mass ratio of acid leaching solution: hexadecyltrimethylammonium bromide: n-butanol: cyclohexane was 1:1:3:7.

[0050] (5) Prepare a 2 mol / L sodium carbonate solution, mix the sodium carbonate solution with hexadecyltrimethylammonium bromide, n-butanol and cyclohexane, and stir evenly at room temperature for 70 min to obtain microemulsion b. The mass ratio of sodium carbonate solution: hexadecyltrimethylammonium bromide: n-butanol: cyclohexane is 1:1:3:7.

[0051] (6) The microemulsion a and the microemulsion b are stirred and mixed at room temperature (25° C.) to react. After the reaction, a centrifuge is used to separate the solid and the liquid. The separated solid phase product is washed with deionized water and anhydrous ethanol, and then dried at 80° C. for 12 hours to obtain nano calcium carbonate.

[0052] Example 4

[0053] A method for preparing nano calcium carbonate based on alkali residue comprises the following steps:

[0054] (1) Alkali slag with a calcium content of more than 30% from industrial solid waste is used as the alkali slag raw material. The alkali slag raw material is first crushed, dried at 100°C for 24 hours, and then ground to a particle size of -0.038 mm accounting for ≥70% of the total mass of the alkali slag to obtain alkali slag powder.

[0055] (2) Mixing the alkali residue powder and the hydrochloric acid solution to obtain an acid leaching solution. The concentration of the hydrochloric acid solution is 4.5 mol / L, and the mass ratio of the alkali residue powder to the hydrochloric acid solution is 1:3.

[0056] (3) After the acid leaching solution is mixed evenly, 5 mol / L NaOH solution is added to the acid leaching solution to adjust the pH value of the acid leaching solution to 12, and the solution is transferred to a 500 mL wide-mouth bottle.

[0057] (4) The pH-adjusted acid leaching solution was mixed with hexadecyltrimethylammonium bromide, n-butanol and cyclohexane, and stirred evenly at room temperature for 70 minutes to obtain microemulsion a. The mass ratio of acid leaching solution: hexadecyltrimethylammonium bromide: n-butanol: cyclohexane was 1:3:5:5.

[0058] (5) Prepare a 1 mol / L sodium carbonate solution, and mix the sodium carbonate solution with hexadecyltrimethylammonium bromide, n-butanol and cyclohexane, and stir evenly at room temperature for 60 minutes to obtain microemulsion b. The mass ratio of sodium carbonate solution: hexadecyltrimethylammonium bromide: n-butanol: cyclohexane is 1:1:3:5.

[0059] (6) The microemulsion a and the microemulsion b are stirred and mixed at room temperature (25° C.) to react. After the reaction, a centrifuge is used to separate the solid and the liquid. The separated solid phase product is washed with deionized water and anhydrous ethanol, and then dried at 80° C. for 12 hours to obtain nano calcium carbonate.

[0060] Comparative Example 1

[0061] The preparation method is the same as that of Example 1. The difference is that in step (6), the mixing temperature of microemulsion a and microemulsion b is adjusted to 60°C.

[0062] Comparative Example 2

[0063] The preparation method is the same as that of Example 1. The difference is that in step (6), the mixing temperature of microemulsion a and microemulsion b is adjusted to 80°C.

[0064] from Figure 2-Figure 4 It can be seen that when the mixing temperature of microemulsion a and microemulsion b is 25°C (room temperature), the particle size of the prepared nano-calcium carbonate is the smallest, reaching 70nm, and the particle size and morphology are uniform.

[0065] The parts not mentioned in the above methods can be realized by adopting or drawing on existing technologies.

[0066] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing nano calcium carbonate based on alkali residue, characterized in that The following steps are involved: (1) grinding the alkali residue raw material to obtain alkali residue powder; (2) mixing the alkali residue powder and the hydrochloric acid solution to obtain an acid leaching solution; (3) adjusting the pH value of the acid leaching solution; (4) mixing the pH-adjusted acid leaching solution with hexadecyltrimethylammonium bromide, n-butanol and cyclohexane, and stirring evenly to obtain a microemulsion a; (5) preparing a sodium carbonate solution, and mixing the sodium carbonate solution with hexadecyltrimethylammonium bromide, n-butanol and cyclohexane, and stirring uniformly to obtain a microemulsion b; (6) mixing the microemulsion a and the microemulsion b to react, performing solid-liquid separation after the reaction, and washing and drying the separated solid phase product to obtain nano calcium carbonate.

2. A method for preparing nano calcium carbonate based on alkali residue according to claim 1, characterized in that: In step (1), the alkali residue raw material adopts alkali residue with a calcium content of more than 30%; the alkali residue raw material is ground to a particle size less than 0.038 mm, which accounts for ≥70% of the total mass of the alkali residue.

3. A method for preparing nano calcium carbonate based on alkali residue according to claim 1, characterized in that: In step (1): before grinding the alkali residue raw material, the alkali residue raw material is crushed and dried; the drying temperature is controlled to be 80-105° C. and the drying time is 24-48 hours.

4. A method for preparing nano calcium carbonate based on alkali residue according to claim 1, characterized in that: In step (2), the concentration of the hydrochloric acid solution is 4-5 mol / L, and the mass ratio of the alkali residue powder to the hydrochloric acid solution is 1:3-5.

5. A method for preparing nano calcium carbonate based on alkali residue according to claim 1, characterized in that: In step (3): the pH value of the acid leaching solution is adjusted to 11-12 by adding NaOH solution to the acid leaching solution.

6. A method for preparing nano calcium carbonate based on alkali residue according to claim 1, characterized in that: In step (4), the acid leaching solution: hexadecyltrimethylammonium bromide: n-butanol: cyclohexane are mixed in a mass ratio of 1:1-3:3-5:5-7.

7. A method for preparing nano calcium carbonate based on alkali residue according to claim 1, characterized in that: In step (5), the concentration of the sodium carbonate solution is 0.5-2 mol / L; the sodium carbonate solution: hexadecyltrimethylammonium bromide: n-butanol: cyclohexane are mixed in a mass ratio of 1:1-3:3-5:5-7.

8. A method for preparing nano calcium carbonate based on alkali residue according to claim 1, characterized in that: In step (4) and step (5): the mixture is stirred evenly at room temperature for 50-70 minutes.

9. A method for preparing nano calcium carbonate based on alkali residue according to claim 1, characterized in that: In step (6): the reaction is controlled to be carried out at room temperature; solid-liquid separation is performed using a centrifuge; the solid phase product is washed with deionized water and anhydrous ethanol; the drying temperature is 60-80° C., and the drying time is 12-24 hours.

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