Method for synergistic smelting of red mud and plastic steel door and window grinding powder, product and application thereof

Abstract

The application discloses a kind of bauxite and plastic steel door and window grinding powder synergic smelting method and product and application, in which, a kind of bauxite and plastic steel door and window grinding powder synergic smelting method, comprising: raw material acquisition, respectively obtains plastic steel door and window grinding powder and bauxite;By adding or not adding flux control alkalinity R in raw material is 0.8-1.2, by adding or not adding reducing agent control C / Fe mass ratio is 0.3-0.5;Wherein, alkalinity R=ω (CaO) % / [ω (SiO2) %+ω (Al2O3) %];Smelting, after raw material is mixed uniformly, high-temperature reduction smelting 60-120min under the condition of 1400 DEG C-1600 DEG C, obtain metal iron phase and slag phase.The application uses C and CaO in plastic steel door and window grinding powder, which can replace the use of part of flux and reducing agent, greatly reduce the amount of flux and reducing agent, reduce cost;At the same time, the slag phase prepared by it is applied to PVC composite material, and the application performance of plastic product can also be improved, and the effect is excellent.

Description

Technical Field

[0001] This invention relates to the field of waste utilization such as red mud, specifically to a method, product, and application of co-smelting red mud and PVC window and door powder. Background Technology

[0002] Red mud is a major solid waste generated in the alumina industry. Depending on the production process, red mud is mainly classified into sintering red mud, Bayer process red mud, and sintering-Bayer combined red mud. my country is a major alumina producer, generating approximately 0.8-1.5 tons of red mud per ton of alumina. The annual increase in red mud is about 70 million tons, with a cumulative total exceeding one billion tons. However, the utilization rate of red mud is only 4%. Large quantities of red mud are stored in open-air dams and buried, which not only occupies significant land resources but also damages the ecological environment. Developing methods for reducing and recycling red mud is of great significance for environmental protection and the green and sustainable development of the alumina industry.

[0003] High-iron red mud contains approximately 60% iron oxide and can be used as a rich iron raw material for reduction smelting. The mass percentage composition of oxides in high-iron red mud is approximately: Fe₂O₃ 64.33%, Al₂O₃ 9.21%, SiO₂ 3.70%, CaO 1.36%, and TiO₂ 5.30%. However, the slag produced by direct reduction smelting of high-iron red mud is high-alumina slag, with a high melting point and high viscosity, leading to difficulties in slag-iron separation during the smelting process. Therefore, a certain amount of CaO and SiO₂ needs to be added during the reduction smelting process to adjust the slag type and form a low-melting-point and low-viscosity slag phase.

[0004] Currently, in the direct reduction smelting process of red mud, the melting point and viscosity of the slag are mainly reduced by adding alkaline fluxes such as limestone and quicklime, thereby achieving good slag-iron separation during the red mud reduction smelting process. However, this method requires the addition of a relatively large amount of flux and reducing agent to achieve good slag-iron separation, resulting in high production costs.

[0005] Meanwhile, the slag produced from red mud reduction smelting for ironmaking is mainly used to prepare cement active powder or directly to produce building materials. However, the slag from red mud reduction smelting contains approximately 70% sodium oxide, which is not completely removed. Therefore, when red mud reduction smelting slag is used directly to prepare cement active powder and building materials, it faces problems such as insufficient activity and high alkali blooming. Furthermore, when products using slag as raw material are applied in the construction industry, there is a soil pollution problem caused by the seepage of alkali from the red mud slag, making large-scale application difficult. Summary of the Invention

[0006] Therefore, the technical problem to be solved by the present invention is to overcome the defects of the existing red mud reduction smelting, which increases the cost by adding a large amount of molten material and the resulting slag cannot be well utilized, thereby providing a method, product and application for the co-smelting of red mud and plastic steel doors and windows by grinding.

[0007] A method for co-smelting red mud and PVC window / door powder, comprising:

[0008] Raw material acquisition: plastic steel door and window powder and red mud were obtained separately; the basicity R in the raw materials was controlled to be 0.8-1.2 by adding or not adding flux, and the C / Fe mass ratio was controlled to be 0.3-0.5 by adding or not adding reducing agent; wherein, basicity R = ω(CaO)% / [ω(SiO2)%+ω(Al2O3)%];

[0009] Smelting involves mixing the raw materials evenly and then performing high-temperature reduction smelting at 1400℃-1600℃ for 60-120 minutes to obtain the metallic iron phase and slag phase.

[0010] The reducing agent is at least one of pulverized coal, coke, and semi-coke;

[0011] And / or, the flux is SiO2 or CaO, preferably quartz sand or limestone.

[0012] The calcium carbonate content in the PVC window and door powder is ≥25%;

[0013] And / or, the particle size of the PVC window and door grinding powder is less than 60 mesh, preferably less than 200 mesh.

[0014] A slag phase was prepared by the above-mentioned method of co-smelting red mud and plastic steel doors and windows through grinding.

[0015] The application of the slag phase prepared by the above-mentioned method of co-melting red mud and PVC doors and windows through grinding and smelting in PVC composite materials.

[0016] A PVC composite material, the raw material of which includes the slag phase prepared by the above-mentioned method of co-melting red mud and plastic steel door and window powder.

[0017] The raw materials of the PVC composite material also include PVC, toughening agent, plasticizer, stearate, polyethylene wax and stabilizer; by weight, the slag phase is 50-100 parts, PVC is 100 parts, toughening agent is 12-20 parts, plasticizer is 3-8 parts, stearate is 1-2 parts, polyethylene wax is 1-2 parts and stabilizer is 8-12 parts.

[0018] The plasticizer is epoxidized soybean oil or hexamethylene adipate;

[0019] And / or, the stabilizer is a calcium-zinc stabilizer or an organotin stabilizer;

[0020] And / or, the toughening agent is chlorinated polyethylene, methyl methacrylate-butadiene-styrene terpolymer, or nano-sized calcium carbonate.

[0021] A method for preparing a PVC composite material includes: mixing weighed raw materials at high speed to obtain a mixture, and then sequentially performing open milling, vulcanization, and compression molding.

[0022] The set temperature of the front and rear rollers during the open milling process is 175-182℃;

[0023] And / or, the temperature of the upper and lower plates during vulcanization is 180-190°C.

[0024] The technical solution of this invention has the following advantages:

[0025] 1. The present invention provides a method for co-smelting red mud and PVC window and door powder, which uses PVC window and door powder as raw material and combines it with red mud. The C and CaO in the PVC window and door powder can replace part of the flux and reducing agent, which greatly reduces the amount of flux and reducing agent used and reduces costs.

[0026] Specifically, PVC window and door powder is a powder material produced by crushing and grinding waste plastic windows and doors. It contains a certain amount of calcium carbonate (approximately 25%-60%), which decomposes at high temperatures to form calcium oxide and carbon dioxide. Therefore, it can replace part of the flux to adjust the slag profile during the reduction smelting of high-speed iron red mud. That is, by adding an appropriate amount of PVC window and door powder and red mud for synergistic reduction smelting, the calcium oxide component formed by the decomposition of calcium carbonate in the PVC window and door powder and the alumina and silicon oxide in the high-speed iron red mud form a low-melting-point and low-viscosity slag phase, achieving good separation of slag and iron during the reduction smelting of high-speed iron red mud. The main chemical reactions that occur during the melting and reduction process are:

[0027] CaCO3=CaO+CO2 (1)

[0028] Fe₂O₃ + 3C = 3CO + 2Fe (2)

[0029] CO2 + C = 2CO (3)

[0030] CO + Fe₂O₃ = Fe + CO₂ (4);

[0031] Meanwhile, by controlling the alkalinity R to 0.8-1.3 and the C / Fe mass ratio to 0.3-0.5, this invention not only effectively meets the purpose of achieving good slag-iron separation in the reduction smelting of high-iron red mud, but also effectively ensures that the separated slag phase can be effectively used in the preparation of PVC composite materials, realizing the full utilization of the slag phase. Furthermore, the slag phase can be used to improve the application performance of plastic products, resulting in excellent mechanical properties of PVC composite materials.

[0032] Furthermore, as can be seen from the reaction formula of the main chemical reaction (4) above, the CO produced by the combustion of plastic in the PVC window and door grinding process can accelerate the reduction efficiency to a certain extent.

[0033] 2. The present invention provides a method for the co-smelting of red mud and PVC-U doors and windows through grinding, which simultaneously reduces the amount of red mud and PVC-U doors and windows and enables resource utilization, while reducing the amount of flux and reducing agent used, thereby improving economic efficiency.

[0034] 3. The PVC composite material provided by this invention utilizes the slag phase, which not only realizes the application of red mud throughout the entire process, but also effectively utilizes the slag phase to improve the application performance of plastic products, resulting in excellent mechanical properties of the PVC composite material with remarkable effects. Attached Figure Description

[0035] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0036] Figure 1 This is a process flow diagram of an embodiment of the present invention. Detailed Implementation

[0037] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0038] For experiments not specifically described in the examples, the procedures or conditions should be followed according to the conventional experimental procedures described in the literature in this field. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products.

[0039] Example 1

[0040] The preparation process of a PVC composite material, such as Figure 1 As shown, it includes:

[0041] (1) Red mud reduction smelting: 50 wt% calcium carbonate plastic steel door and window powder (of which C content is 15%) is used and passed through a 200 mesh sieve for later use; in this embodiment, 500 g of red mud and 206.26 g of plastic steel door and window powder are used.

[0042] The composition of the red mud is as follows: Fe2O3 64.33%, Al2O3 9.21%, SiO2 3.70%, CaO 1.36%, TiO2 5.30%; after conversion to the mass percentage of metal elements, the proportions are as follows: Fe 45.03%, Al 4.88%, Ca 0.97%, Si 1.73%.

[0043] That is, in the red mud, the ω(Al2O3)% content is 9.21%, the ω(SiO2)% content is 3.70%, and the ω(CaO)% content is 1.36%;

[0044] The calculated ω(CaO)% content in the PVC window and door powder is (50%*56) / 100=28%;

[0045] Based on the combined results, the content of ω(Al2O3) in the raw materials is approximately 9.21%*500 / (500+206.26)=6.5%, the content of ω(SiO2) is approximately 3.70%*500 / (500+206.26)=2.6%, and the content of ω(CaO) is approximately (1.36%*500+28%*206.26) / (500+206.26)=9.1%.

[0046] In this embodiment, the basicity R can be controlled to 1 without adding SiO2 powder, meaning no flux is added. The C / Fe mass ratio is controlled to 0.3 in this embodiment; calculation shows that only 67.5g of reducing coal powder with 90% carbon is needed.

[0047] Plastic steel doors and windows are ground into powder and mixed with red mud and coal powder to form pellets. The pellets are then reduced and smelted in a high-temperature reduction furnace at 1450℃ for 60 minutes to obtain metallic iron phase and slag phase with iron content of less than 1.28%.

[0048] (2) Molding of PVC composite material: Grind the slag phase to a particle size of 800 mesh for later use. Weigh 100 parts of type 8 PVC resin powder, 50 parts of the above-mentioned ground slag phase, 3 parts of epoxidized soybean oil, 2 parts of polyethylene wax, 2 parts of stearate, 10 parts of calcium zinc stabilizer, and 15 parts of chlorinated polyethylene (CPE-135A). Mix at high speed with the front and rear rollers set at a temperature of 175-182℃. Process the mixture into shape and place the plastic sheet after processing into shape in a flat vulcanizing machine with an upper and lower plate temperature of 180-190℃ for high-temperature molding.

[0049] Example 2

[0050] A process for preparing a PVC composite material includes:

[0051] (1) Red mud reduction smelting: Plastic steel door and window powder containing 60wt% calcium carbonate (of which, C content is 11.4%) is passed through a 200-mesh sieve for later use; in this embodiment, 500g of red mud and 210.12g of plastic steel door and window powder are used; wherein, the composition of the red mud is the same as in Example 1.

[0052] That is, in the red mud, the ω(Al2O3)% content is 9.21%, the ω(SiO2)% content is 3.70%, and the ω(CaO)% content is 1.36%;

[0053] The calculated ω(CaO)% content in the PVC window and door powder is (60%*56) / 100 = 33.6%;

[0054] Based on the combined results, the content of ω(Al2O3) in the raw materials is approximately 9.21%*500 / (500+210.12)=6.48%, the content of ω(SiO2) is approximately 3.70%*500 / (500+210.12)=2.61%, and the content of ω(CaO) is approximately (1.36%*500+33.6%*210.12) / (500+210.12)=10.90%.

[0055] In this embodiment, the basicity R can be controlled to 1.2 without adding SiO2 powder, meaning that no flux is needed. Simultaneously, the C / Fe mass ratio is controlled to 0.5 in this embodiment. Calculations show that only 112.5g of reducing coal powder containing 90% carbon is required.

[0056] Plastic steel doors and windows are ground into powder and mixed with red mud and coal powder to form pellets. The pellets are then reduced and smelted in a high-temperature reduction furnace at 1450℃. After smelting for 45 minutes, metallic iron phase and slag phase with iron content of less than 0.89% can be obtained respectively.

[0057] (2) Molding of PVC composite material: Grind the slag phase to a particle size of 700 mesh for later use. Weigh 100 parts of type 8 PVC resin powder, 100 parts of the above-mentioned ground slag phase, 5 parts of epoxidized soybean oil, 2 parts of polyethylene wax, 2 parts of stearate, 12 parts of calcium zinc stabilizer, and 20 parts of chlorinated polyethylene (CPE-135A). Mix at high speed with the front and rear rollers set at a temperature of 175-182℃. Process the mixture into shape and place the plastic sheet after processing into shape in a flat vulcanizing machine with an upper and lower plate temperature of 180-190℃ for high-temperature molding.

[0058] Example 3

[0059] A process for preparing a PVC composite material includes:

[0060] (1) Red mud reduction smelting: PVC window and door powder containing 25wt% calcium carbonate (of which C content is 19.5%) is passed through a 200-mesh sieve for later use; in this embodiment, 500g of red mud and 250g of PVC window and door powder are used. The composition of the red mud is the same as in Example 1.

[0061] That is, in the red mud, the ω(Al2O3)% content is 9.21%, the ω(SiO2)% content is 3.70%, and the ω(CaO)% content is 1.36%;

[0062] The calculated ω(CaO)% content in the PVC window and door powder is (25%*56) / 100=14%;

[0063] Based on the combined results, the content of ω(Al2O3) in the raw materials is approximately 9.21%*500 / (500+250)=6.14%, the content of ω(SiO2) is approximately 3.70%*500 / (500+250)=2.47%, and the content of ω(CaO) is approximately (1.36%*500+14%*250) / (500+250)=5.57%.

[0064] In this embodiment, adding 9.84g of CaO powder can control the alkalinity R to 0.8. Simultaneously, the C / Fe mass ratio is controlled at 0.4 in this embodiment. Calculations show that 90g of reducing coal powder containing 90% carbon is required.

[0065] Plastic steel window and door powder is mixed with red mud, reduced coal powder and CaO powder to form pellets. The pellets are then reduced and smelted in a high-temperature reduction furnace at 1600℃ for 30 minutes to obtain metallic iron phase and slag phase with iron content of less than 1.39%.

[0066] (2) Molding of PVC composite material: Grind the slag phase to a particle size of 700 mesh for later use. Weigh 100 parts of type 8 PVC resin powder, 70 parts of the above-mentioned ground slag phase, 8 parts of hexamethylene adipate, 1 part of polyethylene wax, 1 part of stearate, 8 parts of organotin stabilizer, and 12 parts of nano-grade calcium carbonate. Mix at high speed. Set the front and rear rollers to a temperature range of 175-182℃. Process the mixture into shape. Then, put the plastic sheet after processing into a flat vulcanizing machine with an upper and lower plate temperature of 180-190℃ for high-temperature molding.

[0067] Example 4

[0068] A process for preparing a PVC composite material includes:

[0069] (1) Red mud reduction smelting: Use plastic steel door and window powder containing 60wt% calcium carbonate (of which, C content is 11.4%), and pass it through a 200-mesh sieve for later use; in this embodiment, 500g of red mud and 340.45g of plastic steel door and window powder are used.

[0070] The composition of the red mud is as follows: Fe2O3 11.77%, Al2O3 25.48%, SiO2 20.58%, CaO 13.97%, TiO2 4.14%; after conversion to the mass percentage of metal elements, the proportions are as follows: Fe 8.24%, Al 13.49%, Ca 9.98%, Si 9.60%.

[0071] That is, in the red mud, the ω(Al2O3)% content is 25.48%, the ω(SiO2)% content is 20.58%, and the ω(CaO)% content is 13.97%;

[0072] The calculated ω(CaO)% content in the PVC window and door powder is (60%*56) / 100 = 33.6%;

[0073] Based on the combined results, the content of ω(Al2O3) in the raw materials is approximately 25.48%*500 / (500+340.45)=15.16%, the content of ω(SiO2) is approximately 20.58%*500 / (500+340.45)=12.11%, and the content of ω(CaO) is approximately (13.97%*500+33.6%*340.45) / (500+340.45)=21.92%.

[0074] In this embodiment, the basicity R can be controlled to 0.8 without adding flux, meaning no flux is added in this embodiment. In this embodiment, the C / Fe mass ratio is controlled to be 0.3. Through conversion, it can be seen that the amount of reducing coal powder with 90% carbon content added is 17.66g.

[0075] Plastic steel doors and windows are ground into powder and mixed with red mud and coal powder to form pellets. The pellets are then reduced and smelted in a high-temperature reduction furnace at 1450℃ for 60 minutes to obtain the metallic iron phase and the slag phase with an iron content of less than 1.51%.

[0076] (2) Molding of PVC composite material: Grind the slag phase to a particle size of 800 mesh for later use. Weigh 100 parts of type 8 PVC resin powder, 50 parts of the above-mentioned ground slag phase, 3 parts of epoxidized soybean oil, 2 parts of polyethylene wax, 2 parts of stearate, 10 parts of calcium zinc stabilizer, and 15 parts of chlorinated polyethylene (CPE-135A). Mix at high speed with the front and rear rollers set at a temperature of 175-182℃. Process the mixture into shape and place the plastic sheet after processing into shape in a flat vulcanizing machine with an upper and lower plate temperature of 180-190℃ for high-temperature molding.

[0077] Example 5

[0078] A process for preparing a PVC composite material includes:

[0079] (1) Red mud reduction smelting: Use plastic steel door and window powder containing 60wt% calcium carbonate (of which, C content is 11.4%), and pass it through a 200-mesh sieve for later use; in this embodiment, 500g of red mud and 340.45g of plastic steel door and window powder are used.

[0080] The composition of the red mud is as follows: Fe2O3 11.77%, Al2O3 25.48%, SiO2 20.58%, CaO 13.97%, TiO2 4.14%; after conversion to the mass percentage of metal elements, the proportions are as follows: Fe 8.24%, Al 13.49%, Ca 9.98%, Si 9.60%.

[0081] That is, in the red mud, the ω(Al2O3)% content is 25.48%, the ω(SiO2)% content is 20.58%, and the ω(CaO)% content is 13.97%;

[0082] The calculated ω(CaO)% content in the PVC window and door powder is (60%*56) / 100 = 33.6%;

[0083] Based on the combined results, the content of ω(Al2O3) in the raw materials is approximately 25.48%*500 / (500+340.45)=15.16%, the content of ω(SiO2) is approximately 20.58%*500 / (500+340.45)=12.11%, and the content of ω(CaO) is approximately (13.97%*500+33.6%*340.45) / (500+340.45)=21.92%.

[0084] In this embodiment, the basicity R can be controlled to 0.8 without adding flux, meaning no flux is added in this embodiment. The C / Fe mass ratio in this embodiment is 0.3. Calculations show that only 17.66g of reducing coal powder containing 90% carbon is needed.

[0085] After grinding PVC windows and doors into powder, mixing them with red mud and coal powder, the mixture is reduced and smelted in a high-temperature reduction furnace at 1450℃. After smelting for 60 minutes, metallic iron phase and slag phase with iron content of less than 1.6% can be obtained respectively.

[0086] (3) Molding of PVC composite material: Grind the slag phase to a particle size of 800 mesh for later use. Weigh 100 parts of type 8 PVC resin powder, 50 parts of the above-mentioned ground slag phase, 3 parts of epoxidized soybean oil, 2 parts of polyethylene wax, 2 parts of stearate, 10 parts of calcium zinc stabilizer, and 15 parts of chlorinated polyethylene (CPE-135A) and mix at high speed. Set the front and rear rollers to a temperature range of 175-182℃, process the mixture into shape, and put the plastic sheet after processing into a flat vulcanizing machine with an upper and lower plate temperature of 180-190℃ for high-temperature molding.

[0087] Comparative Example 1

[0088] The difference between this comparative example and Example 1 is that the plastic steel door and window grinding process is not used. Instead, flux limestone is used to replace the plastic steel door and window grinding process. The basicity R is controlled to be 1 and the C / Fe mass ratio is 0.3. The limestone, red mud and coal powder are mixed to form pellets. The pellets are then reduced and smelted in a high-temperature reduction furnace at 1450°C. After smelting for 80 minutes, the metallic iron phase and the slag phase with an iron content of less than 1.17% can be obtained respectively.

[0089] This comparative example requires the addition of 103.13g of limestone, which is significantly more expensive than Example 1. Limestone has a purchase cost, and when the iron content is basically the same, the smelting time needs to be extended accordingly, resulting in higher manufacturing costs.

[0090] Comparative Example 2

[0091] The difference between this comparative example and Example 1 is that after the addition of the PVC window and door grinding powder during the smelting process, its basicity R is 0.7 and the C / Fe mass ratio is 0.3. Specifically, this comparative example uses 500g of red mud, 137.08g of PVC window and door grinding powder, and 67.5g of coal powder.

[0092] PVC composite materials were prepared using the same proportions and preparation methods as in Example 1.

[0093] Comparative Example 3

[0094] The difference between this comparative example and Example 1 is that after the addition of the PVC window and door grinding powder during the smelting process, its basicity R is 1.3 and the C / Fe mass ratio is 0.3. Specifically, this comparative example uses 500g of red mud, 275.4g of PVC window and door grinding powder, and 67.5g of coal powder.

[0095] PVC composite materials were prepared using the same proportions and preparation methods as in Example 1.

[0096] Comparative Example 4

[0097] The difference between this comparative example and Example 1 is that the PVC composite material prepared in this comparative example does not contain the slag phase. The slag phase is replaced by calcium carbonate powder. Specifically, the composition of the PVC composite material in this comparative example is as follows: 100 parts of type 8 PVC resin powder, 50 parts of 800-mesh calcium carbonate powder, 3 parts of epoxidized soybean oil, 2 parts of polyethylene wax, 2 parts of stearate, 10 parts of calcium-zinc stabilizer, and 15 parts of chlorinated polyethylene (CPE-135A) are weighed and mixed at high speed. The PVC composite material is prepared using the same method as in Example 1.

[0098] Experimental Example

[0099] The PVC composite materials prepared using the melting results of the examples and comparative examples were cut into standard test specimens and tested according to GB / T1040.2-2006 (Determination of tensile properties of plastics), GB / T9341-2008 (Test of flexural properties of plastics), and GB / T1043.2 (Determination of impact properties of simply supported beams of plastics). The mechanical properties of different specimens were obtained, and the experimental results are shown in Table 1 below.

[0100] Table 1

[0101]

[0102] As shown in Table 1 above, a comparison between Comparative Example 1 and Examples 1-5 reveals that plastic powder with varying calcium carbonate content can be used as a flux in red mud reduction smelting for iron extraction in different processes. Furthermore, utilizing the calcium carbonate in the plastic powder to adjust the slag pattern achieves the same smelting effect as limestone-based slag, with shorter smelting time and lower cost. Moreover, a comparison of the mechanical properties of the PVC composite materials in Comparative Example 1 and Example 1 shows that using limestone-based slag actually results in a slight decrease in mechanical properties compared to using plastic powder. This demonstrates that using plastic powder as a flux in red mud reduction smelting for iron extraction not only shortens smelting time and significantly reduces costs but also effectively improves the mechanical properties of the prepared PVC composite material.

[0103] By comparing Comparative Examples 2-3 with Example 1, it can be seen that under the same process and PVC composite material composition, in Comparative Examples 2-3, when the basicity R of the smelting process is controlled at 0.7 and 1.3 respectively using plastic grinding, the iron content of the smelting slag increases significantly. This proves that too low or too high basicity affects the effective separation of slag and iron. The present invention can effectively reduce the iron content of the smelting slag by controlling the basicity R in the raw materials to 0.8-1.2, and the effect is obvious.

[0104] By comparing Comparative Example 4 and Example 1, it can be seen that, under the same PVC composite material ratio, the PVC composite material prepared by grinding red mud smelting slag and the PVC composite material prepared by calcium carbonate powder of the same particle size have similar mechanical properties, which is sufficient to prove that the slag phase prepared by the method of the present invention can be effectively and fully utilized, and the effect is significant.

[0105] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for the co-smelting of red mud and PVC-U door and window powder, characterized in that, include: Raw material acquisition: plastic steel door and window powder and red mud were obtained separately; the basicity R in the raw materials was controlled to be 0.8-1.2 by adding or not adding flux, and the C / Fe mass ratio was controlled to be 0.3-0.5 by adding or not adding reducing agent; wherein, basicity R=ω(CaO)% / [ω(SiO2)%+ω(Al2O3)%]; Smelting: After the raw materials are mixed evenly, they are smelted at high temperature of 1400℃-1600℃ for 60-120 minutes to obtain metallic iron phase and slag phase; The calcium carbonate content in the PVC window and door powder is ≥25%.

2. The method according to claim 1, characterized in that, The reducing agent is at least one of pulverized coal, coke, and semi-coke; And / or, the flux is SiO2 or CaO.

3. The method according to claim 1, characterized in that, The flux is quartz sand or limestone.

4. The method according to claim 1 or 2, characterized in that, The particle size of the PVC window and door grinding powder is less than 60 mesh.

5. A slag phase, characterized in that, It is prepared by the method of co-smelting red mud and plastic steel doors and windows by grinding and smelting as described in any one of claims 1-4.

6. The application of the slag phase prepared by the method of co-melting red mud and plastic steel doors and windows according to any one of claims 1-4 in PVC composite materials.

7. A PVC composite material, characterized in that, The raw materials include the slag phase prepared by the method of co-smelting red mud and plastic steel doors and windows as described in any one of claims 1-4.

8. The PVC composite material according to claim 7, characterized in that, The raw materials also include PVC, toughening agent, plasticizer, stearate, polyethylene wax and stabilizer; by weight, the slag phase is 50-100 parts, PVC is 100 parts, toughening agent is 12-20 parts, plasticizer is 3-8 parts, stearate is 1-2 parts, polyethylene wax is 1-2 parts and stabilizer is 8-12 parts.

9. The PVC composite material according to claim 8, characterized in that, The plasticizer is epoxidized soybean oil or hexamethylene adipate; And / or, the stabilizer is a calcium-zinc stabilizer or an organotin stabilizer; And / or, the toughening agent is chlorinated polyethylene, methyl methacrylate-butadiene-styrene terpolymer, or nano-sized calcium carbonate.

10. A method for preparing a PVC composite material according to any one of claims 7-9, characterized in that, include: The weighed raw materials are mixed at high speed to obtain a mixture, which is then subjected to open milling, vulcanization, and molding in sequence.

11. The preparation method according to claim 10, characterized in that, The set temperature of the front and rear rollers during the open milling process is 175-182℃; And / or, the temperature of the upper and lower plates during vulcanization is 180-190°C.

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