A solid waste-based sintered brick and its preparation method

Abstract

The present invention relates to the technical field of solid waste recycling, and particularly relates to a solid waste-based sintered brick and a preparation method thereof. The raw materials of the solid waste-based sintered brick include 100 parts of solid waste, 0.5-1 part of sintering aid, 5-10 parts of nano microsilica powder, 10-20 parts of liquid water glass, and 10-20 parts of water; the solid waste includes 0-50 parts of red mud and 50-100 parts of ore powder; the preparation steps include mixing the solid waste and the sintering aid to obtain a premixed dry material; mixing the nano microsilica powder, the liquid water glass and the water to obtain an alkali-activated enhancer; adding the alkali-activated enhancer to the premixed dry material and stirring to obtain a gelling material; vibrating and molding the gelling material to obtain a green brick blank; drying the green brick blank to obtain a dried blank; and roasting the dried blank to obtain the solid waste-based sintered brick. The solid waste-based sintered brick prepared by the present invention has high strength and strong durability, does not produce obvious efflorescence phenomenon, and can realize the resource utilization of solid waste.

Description

Technical Field

[0001] The present invention relates to the technical field of solid waste recycling, and particularly relates to a solid waste-based sintered brick and a preparation method thereof. Background Art

[0002] In industrial production, a large amount of industrial solid waste is often generated, such as red mud discharged during the extraction of alumina in the aluminum industry, slag, ore powder, etc. produced by mineral mining and blast furnace ironmaking. If these solid wastes are directly landfilled, incinerated or discharged into the natural environment in other ways, it will not only cause waste of resources, but also pose a hidden danger to the natural environment. Therefore, how to consume these solid wastes in large quantities is an important research topic.

[0003] In the prior art, one of the main methods to consume solid waste is to use it in construction projects to replace or partially replace traditional building materials, which can reduce the environmental damage caused by the discharge of solid waste while saving the original building materials, thereby reducing the exploitation of natural resources and further reducing the environmental burden. Brick building materials are an ideal application direction for the resource utilization of existing solid waste. Among them, solid waste-based sintered bricks are a kind of brick materials produced with industrial wastes such as fly ash, red mud, and ore powder as the main raw materials, and cement, retarder, sintering aid and other auxiliary materials. Compared with traditional bricks, due to the high-temperature sintering process, the emission of carbon dioxide can be reduced, and the sintered bricks have a relatively compact structure, high strength and durability, and can meet various usage requirements.

[0004] However, in the existing sintered brick production process, in order to improve the strength, the dosage of alkali activator in the raw materials is generally large, and the main raw materials such as red mud are alkaline materials themselves. After adding a large amount of alkali activator, the content of alkaline substances in the obtained sintered bricks will be further increased. Therefore, the existing solid waste-based sintered bricks are extremely prone to alkali efflorescence during use, which affects the internal structure and appearance of the brick body. In severe cases, it may even cause the structure of the sintered brick to be loose, the surface to peel off, and the service life to be short. Summary of the Invention

[0005] Aiming at the technical problem that the use of solid waste to produce sintered bricks in the prior art is prone to alkali efflorescence during use due to the large dosage of alkali activator, the present invention provides a solid waste-based sintered brick and a preparation method thereof. The solid waste-based sintered brick is produced with solid waste as the main raw material, and the obtained solid waste-based sintered brick has high strength, strong durability, does not produce obvious alkali efflorescence, and can realize good resource utilization of solid waste.

[0006] In the first aspect, the present invention provides a solid waste-based sintered brick, comprising the following raw materials in parts by weight:

[0007] 100 parts of solid waste, 0.5 - 1 part of sintering aid, 5 - 10 parts of nano - microsilica powder, 10 - 20 parts of liquid water glass, 10 - 20 parts of water; the solid waste includes 0 - 50 parts of red mud and 50 - 100 parts of ore powder.

[0008] Among them, the nano - microsilica powder serves as a pre - dispersion carrier and can form a crystal nucleus structure in the solid - waste - based sintered brick, significantly improving the durability of the solid - waste - based sintered brick. The strength of the solid - waste - based sintered brick can be adjusted by controlling the addition amount of nano - microsilica powder to meet different construction requirements and effectively reduce the curing cost.

[0009] Furthermore, the sintering aid is nano - alumina, or a combination of nano - alumina with talc powder and / or mica powder. Using nano - alumina as one of the components of the sintering aid can significantly promote the sintering of the sintering system, accelerate the sintering process, and reduce the sintering temperature while ensuring the strength of the sintered brick.

[0010] Furthermore, the ore powder is S105 - grade ore powder, and its main components include silicon dioxide, aluminum oxide, iron oxide, calcium oxide, and magnesium oxide.

[0011] Furthermore, the particle size of the nano - microsilica powder is 20 - 200 nm.

[0012] Furthermore, the modulus of the liquid water glass is 1.0 - 2.5.

[0013] In the second aspect, the present invention provides a preparation method of the above - mentioned solid - waste - based sintered brick, including the following steps:

[0014] (1) Mix the solid waste and the sintering aid evenly to obtain a premixed dry material;

[0015] (2) Mix and stir the nano - microsilica powder, liquid water glass, and water to obtain an alkali - activated strengthening agent;

[0016] (3) Add the alkali - activated strengthening agent to the premixed dry material, stir and mix to obtain a gelling material;

[0017] (4) Put the gelling material into a mold and vibrate it to form a green brick;

[0018] (5) Dry the green brick to obtain a dried blank.

[0019] (6) Place the dried blanks evenly spaced in a high - temperature furnace for roasting. After roasting, cool them in the furnace or take them out directly to obtain the solid - waste - based sintered brick.

[0020] The reaction principle during the preparation process of the solid - waste - based sintered brick is:

[0021] After the alkali activation enhancer is mixed with the premixed dry materials, water glass dissolves Si and Al ions on the surface of red mud and / or mineral powder, and polymerizes, dehydrates, and hardens during the subsequent vibration molding, drying, and roasting processes to form a three-dimensional structure with short-range order and long-range disorder of "Si-O-Al", thereby constituting a three-dimensional network gel material containing [SiO4] (silicon oxygen tetrahedron) and [AlO4] (aluminum oxygen tetrahedron) structures and having the characteristics of a quasi-crystalline state, providing high strength and high durability for the solid waste-based sintered brick.

[0022] The reaction equations involved include:

[0023] SiO2 + OH - + H2O → [H3SiO4] - ;

[0024] AlO2 + OH - + H2O → [H3AlO4] 2- ;

[0025] AlO2 + OH - + H2O → [Al(OH)6] 3- ;

[0026] Ca 2+ + [H3SiO4] - + [H3AlO4] 2- → C(A)-S-H (calcium silicate hydrate gel and / or calcium silicoaluminate hydrate gel);

[0027] Na + + [H3SiO4] - + [H3AlO4] 2- → N-A-S-H (sodium silicoaluminate hydrate gel).

[0028] Furthermore, the specific operation of step (1) is to add red mud, mineral powder, and sintering aids to the mixing kettle and stir at 1800 - 2000 r / min for 2 - 10 min; the specific operation of step (3) is to add the alkali activation enhancer to the premixed dry materials and stir at 1200 - 1500 r / min for 2 - 10 min.

[0029] Furthermore, the drying temperature in step (5) is 80 - 120 °C, and the drying time is 12 - 24 h; the roasting temperature in step (6) is 1000 - 1100 °C, the heating rate during the roasting process is 5 - 20 °C / min, and the holding time is 2 - 6 h.

[0030] The beneficial effects of the present invention are as follows:

[0031] 1. The present invention uses solid wastes such as red mud and mineral powder as the main materials for solid waste-based sintered bricks. The proportion of solid wastes in the raw materials is large and the utilization rate is high, which can consume a large amount of solid wastes and make good resource utilization of solid wastes.

[0032] 2. In the present invention, the dosage of liquid sodium silicate is small. The solid waste-based sintered bricks prepared will not produce obvious efflorescence and delamination phenomena during use, will not damage the aesthetics of the solid waste-based sintered bricks, and have a long service life.

[0033] 3. The present invention uses a sintering aid containing nano-aluminum oxide as an auxiliary material, which can significantly promote the sintering of the sintering system, accelerate the sintering process, reduce the sintering temperature, reduce the production energy consumption of the solid waste-based sintered bricks, and further improve the resource utilization rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required in the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0035] Figure 1 It is a physical picture of the solid waste-based sintered brick prepared in Example 1. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0036] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0037] The mineral powder used in the following Examples 1-8 is of S105 grade provided by Longze Water Purification Materials Co., Ltd., Gongyi City, Henan Province, and its main components are silicon dioxide, aluminum oxide, iron oxide, calcium oxide, magnesium oxide, etc.; the red mud is taken from Zouping, Shandong, and its main components are iron oxide, silicon dioxide, sodium oxide, calcium oxide, titanium dioxide, etc.

[0038] Example 1

[0039] A solid waste-based sintered brick, and the preparation method includes the following steps:

[0040] (1) Add 70 kg of mineral powder, 30 kg of red mud and 0.5 kg of nano-aluminum oxide into a mixing kettle, stir at 1800 r / min for 2 min to mix evenly, and obtain a premixed dry material;

[0041] (2) Mix 10 kg of nano-sized microsilica powder, 10 kg of liquid water glass and 15 kg of water, and stir to obtain an alkali-activated enhancer, wherein the particle size of the nano-sized microsilica powder is 100 - 200 nm, and the modulus of the water glass is 1.5 - 2.0;

[0042] (3) Add the alkali-activated enhancer to the premixed dry material, and stir at 1200 r / min for 2 min to obtain a gelling material;

[0043] (4) Put the gelling material into a mold and vibrate it to form a green brick blank;

[0044] (5) Dry the green brick blank at a drying temperature of 100 °C for 16 h to obtain a dried blank.

[0045] (6) Place the dried blanks evenly spaced in a high-temperature furnace for roasting. The roasting temperature is 1050 °C, the heating rate during roasting is 15 °C / min, the holding time is 4 h, and after roasting, cool with the furnace or take it out directly to obtain the solid waste-based sintered brick.

[0046] Example 2

[0047] A solid waste-based sintered brick, the preparation method comprising the following steps:

[0048] (1) Mix nano-sized alumina and mica powder in a ratio of 1:1 to obtain a sintering aid. Add 50 kg of ore powder, 50 kg of red mud and 0.5 kg of sintering aid to a mixing kettle, and stir at 2000 r / min for 10 min to mix evenly to obtain a premixed dry material;

[0049] (2) Mix 10 kg of nano-sized microsilica powder, 10 kg of liquid water glass and 15 kg of water, and stir to obtain an alkali-activated enhancer, wherein the particle size of the nano-sized microsilica powder is 100 - 200 nm, and the modulus of the water glass is 1.5 - 2.0;

[0050] (3) Add the alkali-activated enhancer to the premixed dry material, and stir at 1500 r / min for 10 min to obtain a gelling material;

[0051] (4) Put the gelling material into a mold and vibrate it to form a green brick blank;

[0052] (5) Dry the green brick blank at a drying temperature of 100 °C for 16 h to obtain a dried blank.

[0053] (6) Place the dried blanks evenly spaced in a high-temperature furnace for roasting. The roasting temperature is 1050 °C, the heating rate during roasting is 15 °C / min, the holding time is 4 h, and after roasting, cool with the furnace or take it out directly to obtain the solid waste-based sintered brick.

[0054] Example 3

[0055] A solid waste-based sintered brick, the preparation method is basically the same as that of Example 2, except that: the addition amount of nano-microsilica powder in step (2) is 5 kg.

[0056] Example 4

[0057] A solid waste-based sintered brick, the preparation method is basically the same as that of Example 2, except that: nano-microsilica powder is not added in step (2);

[0058] Example 5

[0059] A solid waste-based sintered brick, the preparation method is basically the same as that of Example 2, except that: the sintering temperature in step (6) is 1000 °C.

[0060] Example 6

[0061] A solid waste-based sintered brick, the preparation method is basically the same as that of Example 2, except that: the sintering temperature in step (6) is 1100 °C.

[0062] Example 7

[0063] A solid waste-based sintered brick, the preparation method is basically the same as that of Example 2, except that: the addition amount of sintering aid in step (1) is 1 kg, and the sintering temperature in step (6) is 1000 °C.

[0064] The solid waste-based sintered bricks prepared in Examples 1-7 were used to measure the strength of the specimens in accordance with the "Standard for Test Methods of Basic Properties of Building Mortar" (JGJ / T 70-2009). The compressive test was carried out using a DYE-300N pressure testing machine and loaded at a uniform speed at a rate of 2400 N / s ± 200 N / s; and the solid waste-based silicon-aluminate landscape sintered bricks prepared in Examples 1-7 were placed in a dark place for 28 days to observe the efflorescence phenomenon. The test results are shown in Table 1.

[0065] Table 1 Test results of compressive strength and efflorescence

[0066]

[0067] It can be seen that no efflorescence phenomenon occurred in the solid waste-based sintered bricks of Examples 1-7.

[0068] Among them, through the comparison of Examples 2-4, it can be seen that adding nano-microsilica powder to the raw materials of solid waste-based sintered bricks has an excellent effect on improving the strength of the bricks, and the corresponding addition amount of nano-microsilica powder can be selected according to the requirements for the strength of the bricks during construction;

[0069] It can be seen from the comparison between Example 2 and Examples 5-7 that in the temperature range of 1000-1100 °C, the compressive strength of the solid waste-based sintered brick is positively correlated with the sintering temperature. However, increasing the addition amount of the sintering aid can, to a certain extent, compensate for the loss of compressive strength caused by the temperature drop. Therefore, adding an appropriate amount of the sintering aid can reduce the sintering temperature required while maintaining the strength of the brick body.

[0070] Although the present invention has been described in detail by referring to the accompanying drawings and in combination with the preferred embodiments, the present invention is not limited thereto. Without departing from the spirit and essence of the present invention, those of ordinary skill in the art can make various equivalent modifications or substitutions to the embodiments of the present invention, and these modifications or substitutions should all be within the scope of the present invention. / Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered by the protection scope of the present invention.

Claims

1. A solid waste-based sintered brick, characterized in that, It comprises raw materials in the following parts by weight: 100 parts of solid waste, 0.5 - 1 part of sintering aid, 5 - 10 parts of nano micro - silica powder, 10 - 20 parts of liquid water glass, 10 - 20 parts of water; the solid waste includes 0 - 50 parts of red mud and 50 - 100 parts of ore powder; Among them, the sintering aid is nano - alumina, or a combination of nano - alumina with talc powder and / or mica powder.

2. The solid waste-based sintered brick according to claim 1, characterized in that, The particle size of the nano micro - silica powder is 20 - 200 nm.

3. The solid waste-based sintered brick according to claim 1, wherein The ore powder is S105 - grade ore powder, and its main components include silicon dioxide, aluminum oxide, iron oxide, calcium oxide, and magnesium oxide.

4. The solid waste-based sintered brick according to claim 1, wherein The modulus of the liquid water glass is 1.0 - 2.

5.

5. A preparation method of the solid waste-based sintered brick as described in claim 1, characterized in that, It includes the following steps: (1) Mix the solid waste and the sintering aid evenly to obtain a premixed dry material; (2) Mix and stir the nano micro - silica powder, liquid water glass and water to obtain an alkali - activated enhancer; (3) Add the alkali - activated enhancer to the premixed dry material and stir - mix to obtain a gelling material; (4) Put the gelling material into a mold and vibrate it to form a green brick blank; (5) Dry the green brick blank to obtain a dried blank; (6) Place the dried blanks evenly spaced in a high - temperature furnace for roasting, and after the roasting is completed, cool them in the furnace or take them out directly to obtain solid - waste - based sintered bricks.

6. The preparation method according to claim 5, characterized in that, The specific operation of step (1) is to add the solid waste, nano micro - silica powder and sintering aid into a mixing kettle and stir at 1800 - 2000 r / min for 2 - 10 min; the specific operation of step (3) is to add the alkali - activated enhancer to the premixed dry material and stir at 1200 - 1500 r / min for 2 - 10 min.

7. The preparation method according to claim 5, characterized in that, The drying temperature in step (5) is 80 - 120 °C, and the drying time is 12 - 24 h; the roasting temperature in step (6) is 1000 - 1100 °C, the heating rate during roasting is 5 - 20 °C / min, and the holding time is 2 - 6 h.

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