A method for dry forming of lightweight mullite bricks

Abstract

This invention relates to the field of mullite bricks, specifically to a method for dry molding lightweight mullite bricks. The steps involve first mixing expanded perlite, mullite clinker, and kyanite, then pressing the mixture under pressure according to a preset density. Finally, the mixture is fired. This method offers the following advantages over traditional methods in producing lightweight mullite bricks: First, no harmful gases are emitted during firing, meeting environmental protection requirements; second, traditional air-drying and baking processes are eliminated, significantly shortening the production cycle; third, the finished product has stable dimensions after firing, eliminating the need for cutting the fired brick blanks and saving production costs; fourth, the elimination of traditional air-drying and baking processes reduces the required floor space. Calculations show that, within the same production area, the production capacity of this method is approximately 10 times that of traditional mullite brick production.

Description

Technical Field

[0001] This invention relates to the field of mullite bricks, and more specifically to a method for dry molding of lightweight mullite bricks. Background Technology

[0002] The current method for producing mullite bricks is typically a wet process. The main raw materials are kaolin, polystyrene granules (such as foamed polystyrene granules), mullite clinker, and sawdust. The process involves mixing the raw materials with water, then extruding them using a mud extruder to produce brick blanks with a moisture content of approximately 36%. These blanks are then air-dried for 5-6 days until the moisture content reaches approximately 17%, followed by further drying to approximately 3%, and finally firing. This method results in an irregular 6% shrinkage in the overall volume after firing, necessitating the cutting of the bricks on all six sides to achieve the desired dimensions. The disadvantages of this method are as follows: First, it requires a large amount of water, has a long production cycle, and is highly susceptible to weather conditions during air-drying, leading to low efficiency. Second, the polystyrene granules release harmful volatiles during firing (similar to burning plastic). Third, the production cost is high; to obtain bricks of the appropriate size, the fired blanks need to be cut, often yielding only about 1 ton of finished product from approximately 1.6 tons of raw material, resulting in considerable waste. Summary of the Invention

[0003] This invention provides a method for dry molding of lightweight mullite bricks to solve the above-mentioned problems.

[0004] The present invention provides a method for dry molding of lightweight mullite bricks, comprising the following steps:

[0005] Step 1: Mixing raw materials: Add expanded perlite to a mixer, add the pre-set amount of water, and mix well to make the perlite semi-dry and semi-wet. The pre-set amount of water is 2%-3%. Then add mullite clinker powder and kyanite powder and mix thoroughly to ensure that the mullite clinker and kyanite are evenly coated on the expanded perlite. Select the raw materials according to the following weight ratio: expanded perlite content is 20%; mullite clinker content is 65%-70%, and the particle size is 325 mesh; kyanite content is 10%-15%, and the particle size is 150 mesh.

[0006] Step 2: Pressing and molding: Use a brick press to press the raw materials mixed in Step 1 into shape; and adjust the pressing pressure to adjust the molding density as needed;

[0007] Step 3: Firing and Shaping: The brick blanks pressed and shaped in Step 2 are sintered and shaped; the sintering temperature is 1400 degrees Celsius.

[0008] Furthermore, the density of expanded perlite is 70 kg / m³. 3 .

[0009] Furthermore, the mixer used in step one is a zero-gravity mixer.

[0010] Furthermore, the brick press adopts a double-sided pressure hydraulic brick press.

[0011] The beneficial effects of this invention are as follows: Compared with traditional methods, this solution has the following advantages in producing lightweight mullite bricks: First, no harmful gases are emitted during firing, meeting environmental protection requirements; Second, traditional air-drying and drying processes are eliminated, greatly shortening the production cycle; Third, after firing, the finished product dimensions are stable, eliminating the need for cutting and processing the fired brick blanks, saving production costs; Fourth, since traditional air-drying and drying processes are eliminated, the required floor space for production is reduced. According to calculations, within the same production area, the production capacity of this solution is approximately 10 times that of traditional mullite brick production. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is a schematic diagram illustrating the steps of an embodiment of a dry forming method for lightweight mullite bricks according to the present invention. Detailed Implementation

[0014] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0015] An embodiment of the dry forming method for lightweight mullite bricks according to the present invention: A method for dry forming of lightweight mullite bricks, the contents of which are as follows.

[0016] The first step is to select raw materials and formulate them according to the following weight ratio:

[0017] The expanded perlite content is 20%; this raw material has a low density, 1m 3 It weighs approximately 70 kg.

[0018] The mullite clinker content is 65%-70%, and 325 mesh mullite clinker is selected to facilitate the binding of raw materials during mixing.

[0019] The kyanite content is 10%-15%, and a particle size of 150 mesh is selected.

[0020] The second step is to produce lightweight mullite bricks. The production process is as follows:

[0021] 1. Mixing and blending: Add expanded perlite to the mixer, add 2%-3% water, mix well to make the perlite semi-dry and semi-wet, then add mullite clinker powder and kyanite powder and mix thoroughly to make the mullite clinker and kyanite evenly coat the expanded perlite; use a gravity-free mixer.

[0022] 2. Pressing and Molding: The mixed raw materials are pressed into shape using a brick press machine; the pressing pressure is adjusted to regulate the molding density according to requirements; the brick press machine is a double-sided hydraulic brick press; after testing, the density during pressing is 0.8 g / cm³. 3 At that time, the compressive strength of mullite bricks tested was greater than 3 MPa.

[0023] 3. Firing and Shaping: The firing temperature is 1400℃. After practical firing, the volume of the mullite brick shrinks by 0.5% compared to the volume during pressing.

[0024] In the production of mullite bricks, expanded perlite plays three main roles: First, because expanded perlite melts during firing, it creates pores in the mullite bricks, replacing traditional polystyrene granules for pore creation. This process eliminates harmful gas emissions during firing, meeting environmental protection requirements. Second, expanded perlite has a lower density; adjusting its proportion can regulate the overall density. Third, the proportion of expanded perlite affects the firing temperature, thus regulating the overall firing temperature. Kyanite transforms into mullite after firing, exhibiting a 15% volume expansion compared to its pre-firing state. This expansion offsets the volume shrinkage of the mullite clinker during sintering, ensuring that the volume change of the product produced using this method remains within the required range, typically only 0.5%. Therefore, this method has the following advantages over traditional methods in producing lightweight mullite bricks: First, no harmful gases are emitted during firing, meeting environmental protection requirements; second, traditional air-drying and baking processes are eliminated, greatly shortening the production cycle; third, the finished product dimensions are stable after firing, eliminating the need for cutting and processing the fired brick blanks, saving production costs; fourth, the elimination of traditional air-drying and baking processes reduces the floor space required for production. According to calculations, within the same production area, the production capacity of this method is approximately 10 times that of traditional mullite brick production.

[0025] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for dry forming of lightweight mullite bricks, characterized in that... Includes the following steps: Step 1: Mixing raw materials: Add expanded perlite to the mixer, add the pre-set amount of water (2%-3%), and mix well. Then add mullite clinker powder and kyanite powder and mix thoroughly. Select the raw materials according to the following weight ratio: expanded perlite content 20%; mullite clinker content 65%-70% (325 mesh); kyanite content 10%-15% (150 mesh). Step 2: Pressing and molding: Use a brick press to press the raw materials mixed in Step 1 into shape; and adjust the pressing pressure to adjust the molding density as needed; Step 3: Firing and Shaping: The brick blanks pressed and shaped in Step 2 are sintered and shaped; the sintering temperature is 1400 degrees Celsius.

2. The method for dry molding of lightweight mullite bricks according to claim 1, characterized in that: Expanded perlite has a density of 70 kg / m³ 3 .

3. The method for dry molding of lightweight mullite bricks according to claim 1, characterized in that: The mixer used in step one is a zero-gravity mixer.

4. The method for dry molding of lightweight mullite bricks according to claim 1, characterized in that: The brick press is a double-sided hydraulic brick press.

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