CN-121990601-A - Method for preparing nano calcium carbonate based on ceramic microchannel membrane reactor

CN121990601ACN 121990601 ACN121990601 ACN 121990601ACN-121990601-A

Abstract

The invention relates to the technical field of nano material preparation and resource recycling, in particular to a method for preparing nano calcium carbonate based on a ceramic microchannel membrane reactor, which comprises the steps of mixing carbide slag with ammonium chloride solution for leaching reaction, and obtaining calcium-containing mineral solution after solid-liquid separation; adding composite additive into calcium-containing ore solution, pumping the mixed solution into the membrane internal channel of ceramic microchannel membrane reactor, introducing CO 2 -containing gas from the outside of the membrane of ceramic microchannel membrane reactor, dispersing the gas through micropores of membrane wall to form micro-nano bubbles, then making the micro-nano bubbles enter the liquid phase of the membrane internal channel, making gas-liquid two phases contact in cross flow mode and implement carbonization reaction so as to obtain nano calcium carbonate-containing slurry, making gas-liquid separation of the slurry, collecting solid product in the liquid phase, washing and drying so as to obtain the nano calcium carbonate. The invention improves the fixation rate of CO 2 and the conversion rate of calcium element in carbide slag by improving the reaction rate and the mass transfer efficiency, and ensures the high uniformity of the product.

Inventors

ZHOU JUN
ZHOU LINA
LIAO JINGWEN
Jing Shaotao
FAN CHUIGANG
YU CHANGJUN

Assignees

南京工业大学
卡本洛克科技(北京)有限公司
原初科技（北京）有限公司

Dates

Publication Date: 20260508
Application Date: 20260206

Claims (10)

1. The method for preparing nano calcium carbonate based on the ceramic microchannel membrane reactor is characterized by comprising the following steps of: S1, mixing carbide slag with an ammonium chloride solution for leaching reaction, and carrying out solid-liquid separation to obtain calcium-containing ore solution; s2, adding a composite additive into the calcium-containing ore-dissolving liquid; S3, pumping the mixed liquor obtained in the step S2 into a membrane inner channel of the ceramic microchannel membrane reactor, simultaneously introducing gas containing CO 2 from the outer side of the membrane of the ceramic microchannel membrane reactor, dispersing the gas through micropores of a membrane wall to form micro-nano bubbles, then entering a liquid phase of the membrane inner channel, and enabling the gas phase and the liquid phase to contact in a cross flow mode and carry out carbonization reaction to generate slurry containing nano calcium carbonate; S4, carrying out gas-liquid separation on the slurry obtained in the step S3, collecting a solid product in a liquid phase, and washing and drying to obtain nano calcium carbonate; wherein, the membrane component matrix of the ceramic microchannel membrane reactor is made of porous ceramic material, and the surface of the membrane is provided with a hydrophobic and corrosion-resistant modified functional layer.
2. The method for preparing nano calcium carbonate based on the ceramic microchannel membrane reactor according to claim 1, wherein in the step S2, the composite auxiliary agent comprises any two or three of polyphosphate compound, organic polymer compound and surfactant, wherein the mass ratio of the polyphosphate compound, the organic polymer compound and the surfactant is (1-3): 1-5): 0.01-0.10; Preferably, the addition amount of the composite additive is 0.5% -4% of the solid content in the calcium-containing mineral solution.
3. The method for preparing nano calcium carbonate based on the ceramic microchannel membrane reactor according to claim 2, wherein the polyphosphate compound comprises any one or more of sodium pyrophosphate, sodium polyphosphate and sodium hexametaphosphate; The organic high molecular compound comprises any one or more of polyacrylic acid, polyethylene oxide, polyglutamic acid and chitosan; the surfactant comprises any one or two of sodium dodecyl sulfate and polyoxyethylene sorbitan fatty acid ester.
4. The method for preparing nano calcium carbonate based on ceramic micro-channel membrane reactor according to claim 1, wherein in step S3, the carbonization reaction is performed in a two-stage series ceramic micro-channel membrane reactor system; Preferably, the mixed solution firstly enters a channel in a membrane of the primary membrane reactor, and gas containing CO 2 is simultaneously introduced into the outer side of the membrane of the primary membrane reactor to carry out primary carbonization reaction; And (3) aging the slurry after the primary carbonization reaction in a gas-liquid separation tank, and then entering a channel in the membrane of the secondary membrane reactor, and simultaneously introducing gas containing CO 2 into the outer side of the membrane of the secondary membrane reactor to perform the primary carbonization reaction.
5. The method for preparing nano calcium carbonate based on the ceramic micro-channel membrane reactor according to claim 4, wherein the reaction progress is controlled by on-line monitoring of pH value; Preferably, the pH value of the slurry at the outlet of the primary membrane reactor is controlled to be 9.2-9.8, and the pH value of the slurry at the outlet of the secondary membrane reactor is controlled to be below 8.5.
6. The method for preparing nano calcium carbonate based on the ceramic micro-channel membrane reactor according to claim 4 or 5, wherein in the primary membrane reactor, the linear velocity of the mixed liquor in the channels in the membrane is 2.0×10 -5 ～3.0×10 -5 m/s, and the linear velocity of the gas in the channels in the membrane is 3.2×10 -4 ～3.7×10 -4 m/s; In the two-stage membrane reactor, the linear velocity of the slurry in the channels in the membrane was 1.0X10 -5 ～1.5×10 -5 m/s, and the linear velocity of the gas in the channels in the membrane was 6.5X10 -4 ～7.0×10 -4 m/s.
7. The method for preparing nano calcium carbonate based on the ceramic microchannel membrane reactor according to claim 1, wherein in the step S3, the introducing pressure of the gas containing CO 2 is 0.2-0.3 mpa; Preferably, the diameter of the micro-nano bubbles is 0.1-100 μm.
8. The method for preparing nano calcium carbonate based on the ceramic micro-channel membrane reactor according to claim 1, wherein in the step S3, the preparation method of the hydrophobic and corrosion resistant modified functional layer comprises: T1, soaking a membrane module matrix in an alkaline solution, and carrying out hydroxyl load pretreatment; T2, carrying out contact reaction on the membrane substrate treated in the step T1 and long-chain fatty acid of C12-C18 to construct an organic molecular layer; t3, immersing the membrane substrate treated in the step T2 in a silane coupling agent solution for grafting reaction; And T4, sequentially drying and heating the film substrate treated in the step T3 to fix, and forming a hydrophobic and corrosion-resistant modified functional layer on the surface of the film.
9. The method for preparing nano calcium carbonate based on the ceramic microchannel membrane reactor according to claim 1, wherein the membrane module substrate is made of aluminum oxide composite silicon carbide material, and the average pore diameter is 0.1-1.0 μm.
10. The method for preparing nano calcium carbonate based on the ceramic microchannel membrane reactor according to claim 1, wherein in the step S1, the concentration of the ammonium chloride solution is 0.1-1.0 mol/L, the leaching reaction temperature is 40-60 ℃, and the reaction time is 1-3 h.

Description

Method for preparing nano calcium carbonate based on ceramic microchannel membrane reactor Technical Field The invention relates to the technical field of nano material preparation and resource recycling, in particular to a method for preparing nano calcium carbonate based on a ceramic microchannel membrane reactor. Background The nano calcium carbonate is used as an important inorganic chemical raw material, has the advantages of wide sources, low cost, stable chemical properties and the like, and is widely applied to a plurality of industrial fields such as plastics, rubber, paint, papermaking, medicines, foods and the like. After surface modification, the nano calcium carbonate can be well compatible with a high polymer matrix, can be used as a reinforcing framework in plastics to improve the mechanical property and dimensional stability of products, can play roles in reinforcing and improving the processability in rubber, can improve the hiding power, glossiness and durability in paint and printing ink, can be used as a high-grade filler in papermaking to improve the paper quality, and can also be used in a drug delivery system in the field of biological medicine. Along with the upgrading and development of related industries, the requirements for nano calcium carbonate are increasing, and particularly, higher requirements are put on nano-scale products with uniform particle size distribution and good dispersibility. Currently, the main methods for industrially preparing nano calcium carbonate include a bubbling carbonization method, a spray carbonization method, a super gravity method and the like, and all the methods are based on gas-liquid reaction of calcium hydroxide suspension and carbon dioxide gas. The bubbling carbonization method is generally adopted because of simple process and convenient operation, but has the defects of limited gas-liquid contact area, low mass transfer efficiency, difficulty in accurately controlling the nucleation and growth of nano particles, easiness in causing product agglomeration, unstable batch quality and difficulty in realizing continuous production in the reaction process. The spray carbonization method increases the gas-liquid interface through atomization, improves the reaction efficiency to a certain extent, but has the problems of complex equipment structure, high energy consumption, easy blockage of nozzles and the like. The supergravity method utilizes the rotating packed bed to strengthen the mass transfer process, which is favorable for the formation of nano particles, but has large equipment investment and high operation and maintenance cost, and limits the application of the method in small and medium-scale production. In recent years, in order to improve the controllable preparation level of nano calcium carbonate, researchers try to optimize the gas-liquid dispersion state and mass transfer behavior by improving the reactor structure or the mixing mode. For example, a stirring device with a specific structure is used for regulating and controlling the size and distribution of bubbles, and enhancing a gas-liquid contact interface so as to provide a more uniform reaction environment. There is also a study on constructing a bubble liquid film reactor based on a bubble disk stirrer, dividing a reaction liquid into thin liquid films and uniformly dispersing bubbles to form a gas-liquid system with a high specific surface area, thereby accelerating the carbonization reaction rate. These searches provide a beneficial direction for the improvement of the preparation process of nano calcium carbonate. Meanwhile, under the background of resource circulation and low carbon development, the preparation of high added value calcium carbonate products by using industrial solid waste as a calcium source has become an important research direction. The carbide slag is a large amount of alkaline solid waste generated in the acetylene production process, and the main component of the carbide slag is calcium oxide, so that the carbide slag has the potential of being used as a raw material for synthesizing calcium carbonate. The industrial flue gas contains a large amount of carbon dioxide, and the carbon dioxide can be fixed in carbonate products through mineralization reaction, so that the recycling of greenhouse gases is realized. Therefore, developing the nano calcium carbonate synthesis technology with carbide slag as a calcium source and flue gas carbon dioxide as a carbon source has important significance for promoting the development of the high-value conversion and carbon emission reduction co-operation of industrial solid waste. However, most of the existing reaction systems lack effective regulation and control capability on the bubble scale, the carbon dioxide dispersing and dissolving efficiency is low, a large amount of unreacted CO 2 is directly discharged, the carbon fixing efficiency is reduced, and the carbon emission reduction potential of the process i