Gangue sintered hollow wallboard and preparation method thereof

Abstract

The present invention belongs to the field of building materials technology, specifically relating to a sintered hollow gangue wallboard and its preparation method. To maximize the processing of gangue, improve its utilization and added value, address the land occupation and environmental pollution caused by its large accumulation, and provide a gangue wallboard that meets national performance standards, the present invention provides a sintered hollow gangue wallboard. The wallboard is prepared by uniformly mixing 40-50% gangue, 20-30% Huaping clay, 10-20% river sand powder, 5-8% calcium carbide waste slag powder from an acetylene plant, 2-5% calcium aluminate cement, and 0.5-1% titanium slag smelting dust powder to obtain a mixture. The mixture is then mixed with water, stirred, extruded, and then calcined at high temperature. The resulting sintered hollow wallboard has a room-temperature compressive strength of 19.5 MPa, significantly higher than other commercially available sintered hollow wallboards. This is of great significance for the resource and environmentally friendly utilization of gangue.

Description

Technical Field

[0001] The invention belongs to the technical field of building materials, and particularly relates to a gangue sintered hollow wallboard and a preparation method thereof. Background Art

[0002] Gangue is primarily composed of inorganic and organic matter. The inorganic components are primarily SiO₂ (30%-65%) and Al₂O₃ (15%-40%), followed by Fe₂O₃, CaO, MgO, Na₂O, K₂O, SO₃, and smaller amounts of elements such as Ti, Ga, Co, Cu, Zn, Mn, and Mo. The organic matter in gangue is primarily carbon, but also includes H, N, S, and O. Gangue also contains harmful elements such as Pb, Cd, F, and Hg. Disposal of large quantities of this solid waste requires significant land and poses numerous environmental risks, particularly air pollution from spontaneous combustion and water contamination from heavy metal ions. Therefore, comprehensive utilization of gangue is crucial to urgently reduce environmental pollution.

[0003] In recent years, my country has developed many means of utilizing coal gangue resources, such as: (1) Using coal gangue to generate electricity can not only convert coal gangue into valuable energy, but also save a lot of coal and solve the current problem of coal power resource shortage; (2) Using coal gangue to produce fertilizer: Since coal gangue is rich in boron, zinc, copper, cobalt, molybdenum, manganese and other elements, using coal gangue as the main raw material for fertilizer can improve soil quality; (3) Using coal gangue to build roads, fill pits, and reclaim land: Using coal gangue as filler to carry out mine collapse or roadbed and embankment filling can effectively restore the ecological environment of the mine; (4) Preparing composite wall panels based on coal gangue: Using coal gangue as the main raw material, adding other auxiliary ingredients, such as waste slag, fly ash, sludge, etc., to prepare lightweight and heat-insulating wall panels.

[0004] In the current method of preparing composite wall panels based on coal gangue, due to the single usage and limited amount of coal gangue, the prepared wall panels have low compressive strength at room temperature and their performance cannot meet national standards and market demand. Summary of the Invention

[0005] In order to maximize the processing of coal gangue, improve the utilization rate and added value of coal gangue, solve the problems of land occupation and environmental pollution caused by the large-scale accumulation of coal gangue every year, and at the same time provide coal gangue wall panels that can meet national performance standards, especially the compressive strength at room temperature, the present invention provides a coal gangue sintered hollow wall panel and a preparation method thereof.

[0006] The present invention first provides a gangue sintered hollow wallboard, the raw materials of which include the following components by weight percentage:

[0007] 40-50% coal gangue, 20-30% Huaping clay, 10-20% river sand powder, 5-8% calcium carbide waste slag powder from acetylene plant, 2-5% calcium aluminate cement and 0.5-1% titanium slag smelting dust powder.

[0008] Preferably, the following components are included: 45% coal gangue, 30% Huaping clay, 14% river sand powder, 5% acetylene plant carbide waste slag powder, 5% calcium aluminate cement and 1% titanium slag smelting dust powder.

[0009] Wherein, the water content of the raw materials is ≤2wt%.

[0010] The main chemical components of the coal gangue include Al2O3>16%, SiO2>52%, and Fe2O3>2.28%.

[0011] The main chemical components of the Huaping clay, calculated by mass percentage, include SiO2 45.3-51.6%, Al2O3 30-36.8%, Fe2O3 0.65-2.2%, and K2O+Na2O<1.5%.

[0012] Wherein, the SiO2 content of the river sand powder is greater than 85wt%.

[0013] Wherein, the CaO content of the acetylene plant carbide waste slag powder is greater than 75wt%.

[0014] The calcium aluminate cement contains 65-72% Al2O3 and 28-35% CaO.

[0015] Wherein, the TiO2 content of the titanium slag smelting dust powder is greater than 75wt%.

[0016] Among them, the particle size of the coal gangue is ≤3mm, and the particle sizes of the Huaping clay, river sand powder, acetylene plant calcium carbide waste slag powder, calcium aluminate cement, and titanium slag smelting dust powder are all ≤0.088mm.

[0017] The present invention also provides a method for preparing the above-mentioned gangue sintered hollow wallboard, comprising the following steps:

[0018] The coal gangue, Huaping clay, river sand powder, acetylene plant carbide waste slag powder, calcium aluminate cement and titanium slag smelting dust powder are mixed evenly according to weight ratio, water is added, stirred evenly, and the mixture is extruded and calcined at high temperature to obtain the coal gangue sintered hollow wall panel.

[0019] The amount of water added is 12-14 wt% of the mixed raw materials.

[0020] Among them, the extrusion molding pressure is 18 to 20 MPa.

[0021] The high temperature calcination temperature is 1200-1400° C. The high temperature holding time is 4-6 hours.

[0022] Beneficial effects: The present invention uses coal gangue as the main material, and adds a binder calcium aluminate cement alone or in combination to increase the extrusion molding strength, improve the semi-finished product rate of the coal gangue sintered hollow wall panels, and at the same time add Huaping clay to increase the sintering strength and finished product rate of the coal gangue sintered hollow wall panels; the present invention also selects river sand powder as a reinforcing agent, and the river sand powder reacts with the aluminum oxide in the coal gangue to form needle-shaped mullite, which increases the strength after sintering, and selects calcium carbide waste slag powder from an acetylene plant as a mineralizer to provide CaO to promote the sintering of coal gangue into porcelain; and selects titanium slag smelting dust powder containing a high content of TiO2 as a sintering agent to promote the sintering of coal gangue, which is beneficial to improving the sintering strength.

[0023] The performance of the sintered hollow wall panels prepared by the present invention meets the requirements of national standards. Its room-temperature compressive strength is 19.5 MPa, which is much higher than other sintered hollow wall panels on the market. It can also process coal gangue to a large extent, improve the utilization rate and added value of coal gangue, and solve the problems of land occupation and environmental pollution caused by the large-scale accumulation of coal gangue every year. It is of great significance for the resource and environmental protection utilization of coal gangue. DETAILED DESCRIPTION

[0024] To maximize the processing of coal gangue, the present invention uses coal gangue as the main ingredient and improves the performance of coal gangue sintered hollow wallboards by adding Huaping clay, river sand powder, acetylene plant calcium carbide waste slag powder, calcium aluminate cement, and titanium slag smelting dust powder, either alone or in combination. The prepared coal gangue sintered hollow wallboards meet national standards and can be widely used in the building wall industry, greatly improving the utilization rate and added value of coal gangue. At the same time, it can also solve the problems of land occupation and environmental pollution caused by the large-scale annual accumulation of coal gangue.

[0025] The present invention first provides a gangue sintered hollow wallboard, the raw materials of which include the following components by weight percentage:

[0026] 40-50% coal gangue, 20-30% Huaping clay, 10-20% river sand powder, 5-8% calcium carbide waste slag powder from acetylene plant, 2-5% calcium aluminate cement and 0.5-1% titanium slag smelting dust powder.

[0027] Preferably, the following components are included: 45% coal gangue, 30% Huaping clay, 14% river sand powder, 5% acetylene plant carbide waste slag powder, 5% calcium aluminate cement and 1% titanium slag smelting dust powder.

[0028] The addition of Huaping clay into the gangue sintered hollow wallboard of the present invention can increase the sintering strength and the yield of the gangue sintered hollow wallboard.

[0029] In the hollow wallboard sintered with coal gangue of the present invention, river sand powder is selected as a reinforcing agent. The river sand powder reacts with aluminum oxide in the coal gangue to form needle-shaped mullite, thereby increasing the strength after sintering.

[0030] In the hollow wallboard sintered with coal gangue of the present invention, the mineralizer is selected from the calcium carbide waste slag powder of the acetylene plant. The calcium carbide waste slag powder of the acetylene plant contains a certain amount of CaO, which can promote the sintering of coal gangue into porcelain.

[0031] In the gangue sintered hollow wallboard of the present invention, the binder is calcium aluminate cement. The addition of calcium aluminate cement can increase the extrusion molding strength and improve the semi-finished product rate of the gangue sintered hollow wallboard.

[0032] In the hollow wallboard sintered with coal gangue of the present invention, the sintering agent is selected from dust collected from titanium slag smelting. The dust collected from titanium slag smelting contains a certain amount of TiO2, which can promote the sintering of coal gangue and is beneficial to improving the sintering strength.

[0033] In the present invention, the coal gangue particle size is ≤3mm, and the Huaping clay, river sand powder, acetylene plant carbide waste slag powder, calcium aluminate cement, and titanium slag smelting dust powder particle sizes are all ≤0.088mm. Small particle size is conducive to the sintering reaction.

[0034] Among the raw materials used in the present invention, the main chemical components of the coal gangue include Al2O3>16%, SiO2>52%, and Fe2O3>2.28%; the main chemical components of the Huaping clay, measured by mass percentage, include SiO2 45.3-51.6%, Al2O3 30-36.8%, Fe2O3 0.65-2.2%, and K2O+Na2O<1.5%; the SiO2 content of the river sand powder is>85wt%; the CaO content of the acetylene plant calcium carbide waste slag powder is>75wt%; the calcium aluminate cement contains Al2O3 65-72%, CaO 28-35%; and the TiO2 content of the titanium slag smelting dust collection powder is>75wt%. By adopting the above raw materials and preparing the hollow wall panels according to the design formula of the present invention, it is more conducive to improving the strength of the entire hollow wall panels. The raw materials can play a good reinforcing role within the formula range. Adding too much will increase the cost. Since the performance of the raw materials is synergistic, adding too much of certain raw materials will also affect the performance of the hollow wall panels. Adding too little is not conducive to the molding of the hollow wall panels, and the performance will be weakened.

[0035] The present invention also provides a preparation method of the above-mentioned gangue sintered hollow wall panel, comprising the following steps: mixing gangue, Huaping clay, river sand powder, acetylene plant carbide waste slag powder, calcium aluminate cement and titanium slag smelting dust powder according to weight ratio to obtain a mixture, adding water, stirring evenly, extruding and molding, and high-temperature calcining to obtain the gangue sintered hollow wall panel.

[0036] Below, the scheme of the present invention will be explained in conjunction with embodiment.It will be understood by those skilled in the art that the following examples are only used to illustrate the present invention and should not be regarded as limiting the scope of the present invention.In the embodiment, if specific technology or conditions are not indicated, the technology or conditions described in the literature in this area or the product instructions are used.The reagents or instruments used are not indicated by the manufacturer, and are all conventional products that can be obtained by commercial purchase.

[0037] Among the raw materials used in the embodiment of the present invention, the main chemical components of the coal gangue include Al2O3>16%, SiO2>52%, and Fe2O3>2.28%.

[0038] The main chemical components of the Huaping clay, calculated by mass percentage, include SiO2 45.3-51.6%, Al2O3 30-36.8%, Fe2O3 0.65-2.2%, and K2O+Na2O<1.5%.

[0039] The SiO2 content of the river sand powder is greater than 85wt%.

[0040] The CaO content of the acetylene plant carbide waste slag powder is greater than 75wt%.

[0041] The calcium aluminate cement contains 65-72% Al2O3 and 28-35% CaO.

[0042] The titanium slag smelting dust powder has a TiO2 content greater than 75wt%.

[0043] The particle size of the coal gangue is ≤3mm, and the particle sizes of the Huaping clay, river sand powder, acetylene plant calcium carbide waste slag powder, calcium aluminate cement, and titanium slag smelting dust powder are all ≤0.088mm.

[0044] Example 1:

[0045] The raw materials were dried to a moisture content of less than 2wt%. The materials were weighed according to the formula in Table 1. The powders were first mixed, and then water was added to produce an extrusion molding mixture. Mixing was performed using a forced mixer to ensure uniform mixing. An extrusion molding die was designed according to the product shape requirements. The mixture was passed into an extrusion molding machine and extruded at 20MPa at room temperature to produce a semi-finished sintered gangue hollow wallboard. The mixture was then calcined at 1300°C and held at high temperature for 4 hours to produce the finished sintered gangue hollow wallboard. Testing showed that the room-temperature compressive strength of the sintered gangue hollow wallboard was 19.5MPa.

[0046] Table 1 Production ratio of coal gangue sintered hollow wallboard

[0047] Raw material name Particle size / mm Ratio / wt% coal gangue ≤3 45 Huaping clay ≤0.088 30 river sand powder ≤0.088 14 Calcium carbide waste powder from acetylene plant ≤0.088 5 calcium aluminate cement ≤0.088 5 Titanium slag smelting dust powder ≤0.088 1 Water (added) 14

[0048] Comparative Example 1:

[0049] The raw materials were dried to a moisture content of less than 2wt%. The materials were weighed according to the formula in Table 2. The powders were first mixed, and then water was added to produce an extrusion molding mixture. Mixing was performed using a forced mixer to ensure uniform mixing. An extrusion molding die was designed according to the product shape requirements. The mixture was passed into an extrusion molding machine and extruded at 20MPa at room temperature to produce a semi-finished sintered gangue hollow wallboard. The mixture was then calcined at 1300°C and held at high temperature for 4 hours to produce the finished sintered gangue hollow wallboard. Testing showed that the room-temperature compressive strength of the sintered gangue hollow wallboard was 15MPa.

[0050] Table 2 Production ratio of coal gangue sintered hollow wallboard

[0051] Raw material name Particle size / mm Ratio / % coal gangue ≤3 45 Huaping clay ≤0.088 30 river sand powder ≤0.088 20 Calcium carbide waste powder from acetylene plant ≤0.088 0 calcium aluminate cement ≤0.088 5 Titanium slag smelting dust powder ≤0.088 0 Water (added) 14

[0052] Comparative Example 2:

[0053] The raw materials were dried to a moisture content of less than 2wt%. The materials were weighed according to the formula in Table 3. The powders were first mixed, and then water was added to produce an extrusion molding mixture. Mixing was performed using a forced mixer to ensure uniform mixing. An extrusion molding die was designed according to the product shape requirements. The mixture was passed into an extrusion molding machine and extruded at 20MPa at room temperature to produce a semi-finished sintered gangue hollow wallboard. The mixture was then calcined at 1300°C and held at high temperature for 4 hours to produce the finished sintered gangue hollow wallboard. Testing showed that the room-temperature compressive strength of the sintered gangue hollow wallboard was 17.8MPa.

[0054] Table 3 Production ratio of coal gangue sintered hollow wallboard

[0055] Raw material name Particle size / mm Ratio / % coal gangue ≤3 45 Huaping clay ≤0.088 30 river sand powder ≤0.088 19 Calcium carbide waste powder from acetylene plant ≤0.088 0 calcium aluminate cement ≤0.088 5 Titanium slag smelting dust powder ≤0.088 1 Water (added) 14

[0056] Comparative Example 3:

[0057] The raw materials were dried to a moisture content of less than 2wt%. The materials were weighed according to the formula in Table 4. The powders were first mixed, and then water was added to produce an extrusion molding mixture. Mixing was performed using a forced mixer to ensure uniform mixing. An extrusion molding die was designed according to the product shape requirements. The mixture was passed into an extrusion molding machine and extruded at 20MPa at room temperature to produce a semi-finished sintered gangue hollow wallboard. The mixture was then calcined at 1300°C and held at high temperature for 4 hours to produce the finished sintered gangue hollow wallboard. Testing showed that the room-temperature compressive strength of the sintered gangue hollow wallboard was 13.5MPa.

[0058] Table 4 Production ratio of coal gangue sintered hollow wallboard

[0059] Raw material name Particle size / mm Ratio / wt% coal gangue ≤3 40 Huaping clay ≤0.088 23 river sand powder ≤0.088 14 Calcium carbide waste powder from acetylene plant ≤0.088 13 calcium aluminate cement ≤0.088 7 Titanium slag smelting dust powder ≤0.088 3 Water (added) 14

[0060] It should be noted that the specific features, structures, materials, or characteristics described in this specification may be combined in any suitable manner in any one or more embodiments. In addition, those skilled in the art may combine and combine the different embodiments and features of the different embodiments described in this specification without any contradiction.

Claims

1. Coal gangue sintered hollow wallboard, characterized by: The raw materials, measured by weight percentage, are composed of 45% coal gangue, 30% Huaping clay, 14% river sand powder, 5% calcium aluminate cement, and 1% titanium slag smelting dust powder. The preparation method of the coal gangue sintered hollow wallboard comprises the following steps: uniformly mixing the coal gangue, Huaping clay, river sand powder, calcium aluminate cement, and titanium slag smelting dust powder according to weight ratio to obtain a mixture, adding water, stirring, extruding and molding at 18-20 MPa, and calcining at a high temperature of 1200-1400°C to obtain the coal gangue sintered hollow wallboard. The main chemical components of the coal gangue include Al2O3>16%, SiO2>52%, and Fe2O3>2.28%; The main chemical components of the Huaping clay, calculated by mass percentage, include SiO2 45.3-51.6%, Al2O3 30-36.8%, Fe2O3 0.65-2.2%, and K2O+Na2O<1.5%; The SiO2 content of the river sand powder is greater than 85wt%; The CaO content of the acetylene plant carbide waste slag powder is greater than 75wt%; The calcium aluminate cement contains 65-72% Al2O3 and 28-35% CaO; The TiO2 content of the titanium slag smelting dust powder is greater than 75wt%; The coal gangue particle size is ≤3mm, and the Huaping clay, river sand powder, acetylene plant calcium carbide waste slag powder, calcium aluminate cement, and titanium slag smelting dust powder particle sizes are all ≤0.088mm.

2. The gangue sintered hollow wallboard according to claim 1, characterized in that: The water content of the raw materials is ≤2wt%.

3. The method for preparing the hollow wallboard sintered from coal gangue according to claim 1 or 2, characterized in that: The following steps are involved: The coal gangue, Huaping clay, river sand powder, acetylene plant carbide waste slag powder, calcium aluminate cement and titanium slag smelting dust powder are mixed according to weight ratio to obtain a mixture, water is added, and the mixture is stirred evenly. After extrusion molding at 18-20MPa and high-temperature calcination at 1200-1400℃, the coal gangue sintered hollow wall panel is obtained.

4. The preparation method according to claim 3, wherein: The amount of water added is 12-14 wt% of the mixed raw materials.

5. The preparation method according to claim 3, wherein: The high temperature section insulation time is 4 to 6 hours.