Red mud-based geopolymer inorganic reflective coating and preparation method thereof

Abstract

The invention discloses a red mud-based geopolymer inorganic reflective coating and a preparation method thereof. The coating is prepared from Bayer process red mud, a sodium silicate solution, solid sodium hydroxide, styrene-acrylic emulsion, titanium dioxide, talcum powder, a defoaming agent, a flatting agent, a dispersing agent, an anti-settling agent, color paste, 240-mesh glass beads and 300-mesh glass beads. The red mud-based geopolymer inorganic reflective coating prepared by the invention has good adhesive force with a base layer, good mechanical property of a paint film, high pencil hardness and high reflection coefficient. The coating is used for tunnel hole interior decoration and mine hole brightening coating, the reflectivity of the tunnel coating can be effectively enhanced, the tunnel lighting effect is improved, and driving safety is guaranteed. The red mud and the alkali activator are used as geopolymer materials, so that the recycling of solid waste resources is realized, organic substance components in the coating are effectively reduced, and the fireproof performance is excellent.

Description

Technical Field

[0001] The present invention belongs to the technical field of coatings, and particularly relates to a red mud-based geopolymer inorganic reflective coating and a preparation method thereof. Background Art

[0002] The highway construction in China has developed rapidly, and the number and scale of tunnels have also increased significantly. Highway tunnels have the characteristics of strong closure, large changes between light and dark, and strict vehicle speed control, and there are great limitations in aspects such as ventilation, lighting, sight distance, and disaster relief. At present, most of the coatings used for the inner wall coating of tunnels are gray and blue inorganic coatings, with weak diffuse reflection ability. The light and dark changes are large before and after the vehicle enters the tunnel, and the lighting effect in the tunnel is weak, which is not conducive to driving safety. If a traffic accident occurs in the tunnel, it is extremely easy to cause secondary accidents, bringing great difficulties to emergency management and rescue work. To ensure the driving safety of highway tunnels and improve driving comfort, it is the current development focus to take reasonable measures to brighten the tunnels. Summary of the Invention

[0003] Aiming at the defects of the current inorganic coatings for tunnels, under the concept of environmental protection, the present invention enhances the reflective effect and service effect of the coatings, and provides a red mud-based geopolymer inorganic reflective coating and a preparation method thereof.

[0004] The raw materials of the red mud-based geopolymer inorganic reflective coating include, by mass, 40-50 parts of Bayer red mud, 30-40 parts of sodium silicate solution, 3-6 parts of solid sodium hydroxide, 10-20 parts of styrene-acrylic emulsion, 10-20 parts of titanium dioxide, 5-10 parts of talc powder, 0-0.5 parts of defoamer, 0-0.5 parts of leveling agent, 0-0.5 parts of dispersant, 1-3 parts of anti-settling agent, 5-10 parts of color paste, 30-50 parts of 240-mesh glass microspheres, and 10-15 parts of 300-mesh glass microspheres.

[0005] The Bayer red mud is a waste generated during the production of electrolytic aluminum, and its main components are SiO2, Fe2O3, Al2O3, Na2O, and CaO.

[0006] The mass fraction of Na2O in the sodium silicate solution is 11%, and the mass fraction of SiO2 is 33%.

[0007] In the red mud-based geopolymer inorganic reflective coating, the sum of the masses of the sodium silicate solution and the Bayer red mud accounts for 60-80% of the total mass of the coating.

[0008] The defoamer is an organosilicon defoamer, and the dispersant is a silicate dispersant LBCB-1.

[0009] The preparation method of the red mud-based geopolymer inorganic reflective coating is as follows: Step 1: Mix solid sodium hydroxide, styrene acrylic emulsion and sodium silicate solution to prepare an alkali activator; Step 2: After the alkaline activator prepared in step 1 cools down to room temperature, Bayer red mud is added to obtain a base material; Step 3: Stir the base material of step 2 at 20-35°C for 10 minutes, then add titanium dioxide, talcum powder, defoamer, dispersant, and leveling agent, stir evenly, and grind to a particle size of 300-800 mesh; Step 4: Finally, add 240-mesh and 300-mesh glass beads, anti-settling agent, and color paste, and stir thoroughly to obtain the red mud-based polymer inorganic reflective coating.

[0010] The present invention uses red mud and alkali activator as main film-forming substances, adjusts the ratio of red mud and alkali activator by compounding sodium silicate solution and solid sodium hydroxide, and utilizes the reaction between the two to produce a three-dimensional meshed gelling material to improve the mechanical properties of the coating. Adding styrene acrylic emulsion into the coating can improve the film-forming state of the coating, effectively reduce the cracking phenomenon of the paint film, and improve the appearance of the paint film. Adding glass microbeads with mesh sizes that can be filled with each other into the coating, supplemented with titanium dioxide and color paste, improves the reflective performance of the coating. The red mud-based polymer inorganic reflective coating prepared by the present invention has good adhesion to the base layer, good mechanical properties of the paint film, high pencil hardness, and high reflection coefficient. It is used for tunnel decoration and mine cave lighting coating, which can effectively enhance the reflectivity of the tunnel coating, improve the tunnel lighting effect, and ensure driving safety. Using red mud and alkali activator as geopolymer materials effectively realizes the recycling of solid waste resources, and effectively reduces the organic matter components in the coating, and has excellent fireproof performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 Schematic diagram of the reflective principle of red mud-based polymer inorganic reflective coating.

[0012] Figure 2 This is a schematic diagram of the structure of red mud-based polymer inorganic reflective coating.

[0013] In the figure: 1-reflected light, 2-incident light, 3-titanium dioxide / emulsion red mud-based polymer, 4-glass microspheres, 5-microsphere reflective surface, 6-240 mesh glass microspheres, 7-300 mesh glass microspheres, 8-resin, 9-red mud-based polymer coating substrate, 10-cement base. DETAILED DESCRIPTION

[0014] Example 1 Prepare the red mud-based polymer inorganic reflective coating according to mass proportion: (1) 5 parts of solid sodium hydroxide, 15 parts of styrene acrylic emulsion and 40 parts of sodium silicate solution are mixed to prepare an alkali activator; (2) After the alkali activator cools to room temperature, 50 parts of Bayer red mud are added to obtain a base material; (3) After stirring the base material for 10 minutes, add 15 parts of titanium dioxide, 10 parts of talc, 0.1 parts of silicone defoamer, 0.1 parts of silicate dispersant LBCB-1, and 0.1 parts of propylene glycol leveling agent, stir evenly, and grind to a particle size of 600 mesh; Step 4: Finally, add 40 parts of 240-mesh glass microspheres and 15 parts of 300-mesh glass microspheres, 2 parts of polyacrylate anti-settling agent, and 10 parts of water-based color paste, and stir thoroughly to obtain a red mud-based polymer inorganic reflective coating.

[0015] The sodium silicate solution has a mass fraction of Na2O of 11%, a mass fraction of SiO2 of 33%, and a modulus of 1.4. The water-binder ratio of the slurry is 0.52, wherein when calculating the water-binder ratio, the water content in the commercially available water glass solution is used as the water in the water-binder ratio.

[0016] Table 1 Performance test of red mud-based polymer inorganic reflective coating

Claims

1. An inorganic reflective coating based on red mud geopolymers, characterized in that, The raw materials of the coating include, by weight, 40-50 parts of Bayer red mud, 30-40 parts of sodium silicate solution, 3-6 parts of solid sodium hydroxide, 10-20 parts of styrene-acrylic emulsion, 10-20 parts of titanium dioxide, 5-10 parts of talc, 0-0.5 parts of defoaming agent, 0-0.5 parts of leveling agent, 0-0.5 parts of dispersant, 1-3 parts of anti-settling agent, 5-10 parts of color paste, 30-50 parts of 240-mesh glass microspheres, and 10-15 parts of 300-mesh glass microspheres.

2. The inorganic reflective coating of geopolymer based on red mud according to claim 1, characterized in that, The Bayer process red mud is a waste material generated in the production process of electrolytic aluminum, and its main components are SiO2, Fe2O3, Al2O3, Na2O, and CaO.

3. The inorganic reflective coating based on red mud geopolymers according to claim 1, characterized in that, The mass fraction of Na2O in the sodium silicate solution is 11%, and the mass fraction of SiO2 is 33%.

4. The inorganic reflective coating based on red mud geopolymers according to claim 1, characterized in that, The defoamer is an organosilicon defoamer, and the dispersant is a silicate dispersant LBCB-1.

5. The preparation method of the red mud-based geopolymer inorganic reflective coating according to any one of claims 1-4, characterized in that, The method comprises the following preparation steps: Step 1: Mix solid sodium hydroxide, styrene acrylic emulsion and sodium silicate solution to prepare an alkali activator; Step 2: After the alkaline activator prepared in step 1 cools down to room temperature, Bayer red mud is added to obtain a base material; Step 3: Stir the base material of step 2 at 20-35°C for 10 minutes, then add titanium dioxide, talcum powder, defoamer, dispersant, and leveling agent, stir evenly, and grind to a particle size of 300-800 mesh; Step 4: Finally, add 240-mesh and 300-mesh glass beads, anti-settling agent, and color paste, and stir thoroughly to obtain the red mud-based polymer inorganic reflective coating.

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