CN-122006621-A - Continuous coating device and continuous coating production method

CN122006621ACN 122006621 ACN122006621 ACN 122006621ACN-122006621-A

Abstract

The invention provides a continuous coating device and a continuous coating production method, wherein the device comprises a slurry mixing tank, a first composite premixing unit, a first-stage coating tank, a second composite premixing unit, a second-stage coating tank, a pH adjusting tank and a coating post tank which are sequentially communicated; the production method comprises six stages of pulp mixing pretreatment, first-stage composite premixing, first-stage coating reaction, second-stage composite premixing, second-stage coating reaction, pH final adjustment and post-treatment, wherein the first-stage composite premixing comprises first-stage static premixing and first-stage high-shear strengthening mixing, and the second-stage composite premixing comprises second-stage static premixing and second-stage high-shear strengthening mixing. According to the invention, through the two-stage composite premixing of static mixing preliminary dispersion and high shear strengthening dispersion, macroscopic uniformity and microscopic dispersion of the coating agent and the materials are realized, continuous productivity can be adapted, the coating effect is obviously improved, the occupied space of equipment is small, the transformation difficulty is low, and the method is suitable for continuous coating production scenes and has good practicability and industrialization value.

Inventors

SUN LIANG
WU YUYANG
LIU WENJING
CHEN XIAOLI
ZHANG XIANGYANG
CHEN YANQIANG
HAN TAO
WANG YANG
Duan Danhui
SONG JIA

Assignees

龙佰集团股份有限公司

Dates

Publication Date: 20260512
Application Date: 20260326

Claims (10)

1. The continuous coating device is characterized by comprising a slurry mixing tank, a first composite premixing unit, a first-stage coating tank, a second composite premixing unit, a second-stage coating tank, a pH adjusting tank and a coating post tank which are sequentially communicated; the first composite premixing unit comprises a first static mixer and a first high-shear stirring tank which are sequentially communicated, and a discharge port of the first static mixer is communicated with a feed inlet of the first high-shear stirring tank; the second composite premixing unit comprises a second static mixer and a second high-shear stirring tank which are sequentially communicated, and a discharge port of the second static mixer is communicated with a feed port of the second high-shear stirring tank; The feed end of the first static mixer is connected with a first coating agent branched pipe in a bypass mode, and the feed end of the second static mixer is connected with a second coating agent branched pipe in a bypass mode.
2. The continuous coating device according to claim 1, wherein the discharge port of the slurry mixing tank is communicated with the feed port of the first static mixer through a first main pipeline, the discharge port of the first high-shear mixing tank is communicated with the feed port of the first-stage coating tank, the discharge port of the first-stage coating tank is communicated with the feed port of the second static mixer through a second main pipeline, and the discharge port of the second high-shear mixing tank is communicated with the feed port of the second-stage coating tank.
3. The continuous encapsulation apparatus of claim 2, comprising at least one of the following features: (1) The first coating agent branch pipe and the second coating agent branch pipe are respectively provided with a metering pump and a flow control valve; (2) The first high-shear stirring tank and the second high-shear stirring tank are small-sized high-shear stirring tanks, the volume of each small-sized high-shear stirring tank is 3-5 m 3 , and the effective volume is more than or equal to 2.5m 3 ; (3) The first static mixer and the second static mixer are of pipeline structures, the pipe diameter DN is 100-150, and the length is 1.2-1.5 m; (4) The upstream 300-500 mm of the feeding end of the first static mixer is in bypass connection with the first coating agent branched pipe, and the upstream 300-500 mm of the feeding end of the second static mixer is in bypass connection with the second coating agent branched pipe.
4. A continuous encapsulation tool according to claim 3, comprising at least one of the following features: (1) The small high-shear stirring tank is internally provided with a high-shear stirrer with a rotor-stator structure, and the gap between the rotor and the stator is 0.5-1.5 mm; (2) The tank wall of the small high-shear stirring tank is provided with a liquid level meter and a temperature sensor, and the small high-shear stirring tank is externally wrapped with an insulating layer; (3) The internal mixing elements of the first static mixer and the second static mixer are spiral or inclined plates.
5. The continuous encapsulation apparatus of claim 4, comprising at least one of the following features: (1) The stator is provided with a fine shearing hole with the aperture of 1-2 mm; (2) The rotor and the stator are made of acid and alkali corrosion resistant materials; (3) The first static mixer and the second static mixer are made of stainless steel.
6. The continuous coating production method is characterized by adopting the continuous coating device according to any one of claims 1-5 based on a static mixing-high shearing composite premixing continuous coating process, and comprises six stages of slurry mixing pretreatment, first-stage composite premixing, first-stage coating reaction, second-stage composite premixing, second-stage coating reaction, pH final adjustment and post-treatment; The first-stage composite premixing comprises a first-stage static premixing and a first-stage high-shear strengthening mixing, and the second-stage composite premixing comprises a second-stage static premixing and a second-stage high-shear strengthening mixing.
7. The continuous coating process of claim 6, wherein the continuous coating process comprises the steps of: Step (1) pulp mixing pretreatment, namely feeding the materials into a pulp mixing tank to obtain pretreated materials; Step (2) primary static premixing, namely conveying the pretreated material through a first main pipeline, and simultaneously injecting a first coating agent into the first main pipeline; step (3) primary high-shear reinforced mixing, namely continuously feeding the mixed material A into a first high-shear stirring tank to obtain a material system B with even micro-dispersion; Step (4) a first-stage coating reaction, namely feeding a material system B into a first-stage coating tank to finish the preliminary coating reaction, so as to obtain a first-stage coating material C; Step (5) secondary static premixing, namely conveying the primary coating material C through a second main pipeline, and simultaneously injecting a second coating agent into the second main pipeline; Step (6) secondary high-shear strengthening mixing, namely continuously feeding the mixed material D into a second high-shear stirring tank to obtain a material system E with even microscopic dispersion; Step (7) a second-stage coating reaction, namely feeding a material system E into a second-stage coating tank to finish secondary coating to obtain a second-stage coating material F; and (8) pH final adjustment and post-treatment, namely conveying the secondary coating material F into a pH adjustment tank, conveying the material subjected to pH final adjustment into a coating post-tank, and finishing coating treatment to obtain a coating product.
8. The continuous coating process of claim 7, comprising at least one of the following features: A. The outflow flow of the pretreated material in the step (1) is controlled to be 14-22 m 3 /h; B. In the step (2), the flow speed of the material in the first static mixer is controlled to be more than or equal to 1.5m/s, and the inlet and outlet pressure is controlled to be 0.1-0.3 MPa; C. In the step (3), the rotating speed of a high-shear stirrer of a rotor-stator structure is controlled to be 1500-2000 r/min, and the shear rate is more than or equal to 1 multiplied by 10 4 s -1 ; D. in the step (5), the flow speed of the material in the second static mixer is controlled to be more than or equal to 1.5m/s, and the inlet and outlet pressure is controlled to be 0.1-0.3 MPa; E. in the step (6), the rotating speed of a high-shear stirrer of a rotor-stator structure is controlled to be 1500-2000 r/min, and the shear rate is more than or equal to 1 multiplied by 10 4 s -1 .
9. The continuous envelope production method of claim 7 or 8, comprising at least one of the following technical features: A. in the step (1), the concentration of the materials is regulated to 290-310 g/L, and the temperature is controlled to be 50-60 ℃; B. In the step (2), the first coating agent is injected into a first main pipeline through a metering pump according to the flow of 0.5-0.6 m 3 /h; C. in the step (3), the residence time of the materials in the tank is controlled to be 10-15 min, the temperature of the materials in the tank is maintained to be 50-60 ℃, and the liquid level in the tank is maintained to be 60-80% of the volume; D. in the step (4), the residence time in the tank is controlled to be 50-70 min, and the pH value of the outlet is regulated to be 3.2-3.8; E. In the step (5), the second coating agent is injected into a second main pipeline through a metering pump according to the flow of 0.53-0.63 m 3 /h; F. in the step (6), the residence time of the materials in the tank is controlled to be 10-15 min, the temperature of the materials in the tank is maintained to be 50-60 ℃, and the liquid level in the tank is maintained to be 60-80% of the volume; G. In the step (7), the residence time in the tank is controlled to be 160-200 min, and the pH value of the outlet is regulated to be 11.0-11.8; H. In the step (8), sulfuric acid is added into the pH adjusting tank according to the flow of 0.32-0.40 m 3 /h, the pH value of the outlet is adjusted to 6.5-7.1, the residence time is controlled to be 50-70 min for final pH adjustment, and the material after final pH adjustment is sent into the coating post-tank for residence for 3-8 h.
10. The continuous coating production method according to claim 9, wherein the first coating agent is at least one of aluminum sulfate, aluminum ammonium sulfate, polyaluminum chloride and aluminum chloride, and the second coating agent is at least one of sodium metaaluminate, potassium metaaluminate, calcium aluminate and polyaluminum ferric chloride.

Description

Continuous coating device and continuous coating production method Technical Field The invention relates to the technical field of material coating treatment, in particular to a continuous coating device and a continuous coating production method, which are particularly suitable for large-scale continuous coating production. Background In the production fields of powder materials, chemical products and the like, the coating treatment is a key process for improving the stability and the functionality of the products, and the properties of the materials such as moisture resistance, fluidity, chemical stability and the like can be improved by coating a uniform coating layer on the surfaces of the materials. For a large-scale continuous production scene, the existing coating process generally adopts a flow of 'pulp mixing-direct coating-pH adjustment-post treatment', namely, the materials after pulp mixing directly enter a coating tank, and meanwhile, coating agents (such as aluminum sulfate and sodium metaaluminate) are injected into the coating tank according to a set proportion, and are stirred in the tank to realize mixing and coating reaction. However, the existing coating process has the obvious technical defects that on one hand, the volume of a coating tank is larger, the flow rate of a coating agent is relatively smaller, after the coating agent is directly injected into a large-volume coating tank, the phenomenon of uneven mixing of materials and the coating agent is easily caused due to the fact that local concentration is too high or too low, on the other hand, the coating agent such as sodium metaaluminate and the like is easy to form aggregates in an aqueous solution, the aggregates are difficult to thoroughly break up by simply relying on conventional stirring in the coating tank, and the aggregated coating agent can cause uneven thickness and poor compactness of a coating layer on the surface of the materials and seriously affect the coating effect. In addition, uneven mixing can also cause local pH value in the coating tank to deviate from a set range, and further influence the stability and consistency of the coating reaction. In order to solve the problem of uneven mixing, a scheme of adding a single premixing tank is often adopted in the prior art, but the premixing tank with single mechanical stirring has the problems of low mixing efficiency and large occupied space of equipment, microscopic agglomeration of the coating agent is difficult to crack, and the mixing uniformity cannot be fundamentally improved. Therefore, there is a need to develop a coating device and process that is suitable for continuous production, has good mixing effect, and occupies little space, so as to solve the pain in the prior art. In view of this, the present invention has been made. Disclosure of Invention The invention aims at solving the technical problems of uneven thickness and poor compactness of a coating layer caused by uneven mixing and easy agglomeration of a coating agent and materials in the existing coating process, and provides a continuous coating device and a continuous coating production method, wherein a set of composite premixing units are respectively additionally arranged between a slurry mixing tank and a first-stage coating tank and between the first-stage coating tank and a second-stage coating tank, through a two-stage composite premixing mode of static mixing preliminary dispersion and high shear strengthening dispersion, macroscopic uniformity and microscopic dispersion of a coating agent and materials are realized, continuous productivity which is more than or equal to 100t/d (preferably 100-150 t/d) can be adapted, uniformity and stability of a coating layer are obviously improved, coating effect is improved, the occupied space of equipment is small, the transformation difficulty is low, the method is suitable for continuous coating production scenes, and good practicability and industrialization value are realized. In order to achieve the above object of the present invention, the following technical solutions are specifically adopted: a continuous coating device comprises a slurry mixing tank, a first composite premixing unit, a first-stage coating tank, a second composite premixing unit, a second-stage coating tank, a pH adjusting tank and a coating post tank which are communicated in sequence; the first composite premixing unit comprises a first static mixer and a first high-shear stirring tank which are sequentially communicated, and a discharge port of the first static mixer is communicated with a feed inlet of the first high-shear stirring tank; the second composite premixing unit comprises a second static mixer and a second high-shear stirring tank which are sequentially communicated, and a discharge port of the second static mixer is communicated with a feed port of the second high-shear stirring tank; The feed end of the first static mixer is connected with a first coating a