Comprehensive utilization method of titanium-containing blast furnace slag

Abstract

The invention belongs to the field of resource utilization of metallurgical solid waste, and discloses a comprehensive utilization method of titanium-containing blast furnace slag, which comprises the following steps: uniformly mixing titanium-containing blast furnace slag, a carbonaceous reducing agent, a composite phase inversion agent and water according to a mass ratio of 100: (25-35): (40-50): (20-25), granulating, and drying to obtain pellets; wherein the composite phase inversion agent is composed of NaCl and CaCl2 according to the mass ratio of (4-8): 4; under the protective atmosphere, the pellets are subjected to microwave heating to 800-1000 DEG C, and after heat preservation is conducted for 1.5-2.5 h, mixed gas and chlorinated tailings are obtained; the mixed gas is subjected to first-stage condensation separation, second-stage condensation separation and third-stage condensation separation in sequence, and a SiCl4 product, a TiCl4 product and an iron-aluminum salt product containing FeCl3 and / or AlCl3 are obtained in sequence; wherein the condensation temperature of the first-stage condensation separation is 136-140 DEG C, the condensation temperature of the second-stage condensation separation is 102-105 DEG C, and the condensation temperature of the third-stage condensation separation is 12-15 DEG C. According to the method, energy consumption is reduced, the titanium recovery rate is high, and recovery of valuable elements such as silicon and titanium is achieved.

Description

Technical Field

[0001] This invention relates to a comprehensive utilization method for titanium-containing blast furnace slag, belonging to the field of resource utilization of non-ferrous smelting slag (metallurgical solid waste). Background Technology

[0002] Vanadium-titanium magnetite resources are abundant, but during the blast furnace ironmaking process, a large amount of titanium enters the slag phase to form titanium-containing blast furnace slag (the main phases include CaTiO3, Al2O3, SiO2, and FeO). Ironmaking enterprises have a large annual output of titanium-containing blast furnace slag, and the treatment method is often simple stockpiling, which wastes titanium resources and causes environmental pressure. The current mainstream treatment process for titanium-containing blast furnace slag is high-temperature carbonization followed by low-temperature chlorination. This method has three major drawbacks: First, the high-temperature carbonization temperature requires 1600~1800℃, resulting in extremely high energy consumption and high production costs. Second, the chlorination process easily generates pollutants, and the chlorinated tailings cannot be effectively utilized, leading to serious secondary pollution. Third, the chlorinating agents (such as Cl2, see CN108975393A, CN108677025A) are mostly used only once, resulting in resource waste and increased costs. At the same time, the titanium recovery rate can only reach 75~80%, which is difficult to meet the needs of large-scale production. Fourth, the high-temperature carbonization process and the chlorination process usually need to be carried out in separate steps, resulting in a long process flow and high energy consumption (see CN108975393A).

[0003] Microwave heating offers advantages such as selective heating, rapid heating rate, and low energy consumption. It can specifically heat the titanium-rich phase (perovskite phase, mainly composed of CaTiO3) in titanium-containing blast furnace slag. However, the current application of microwave technology in the comprehensive utilization of titanium-containing blast furnace slag still faces challenges, including unreasonable chlorinating agent ratios, incomplete impurity separation, lack of chlorinating agent regeneration, and low resource utilization of tailings, hindering industrial-scale breakthroughs. Therefore, developing a low-energy-consumption, environmentally friendly, and high-recovery-rate comprehensive utilization process for titanium-containing blast furnace slag is of great significance for promoting its resource utilization.

[0004] Chinese invention patent application CN115784298A discloses a method for selectively enriching and extracting titanium from titanium-containing blast furnace slag using microwave. The technical solution is as follows: The titanium-containing blast furnace slag is crushed, ground, dehydrated, and dried; the dried titanium slag is placed in a tubular atmosphere furnace, first heated to 400-500℃ at a rate of 15-20℃ / min, then heated to 800-1000℃ at a rate of 10-15℃ / min, and then heated to 1200-1300℃ at a rate of 5-10℃ / min, held at this temperature for 1-2 hours, and then cooled in the furnace to obtain molten and cooled titanium slag; the molten and cooled titanium slag is placed in a microwave muffle furnace and heated to 1100-1200℃ at a rate of 100-120℃ / min, held at this temperature; then water-quenched, ground, and sorted to obtain calcium titanate product. This patent recovers titanium in the form of calcium titanate, but the titanium recovery rate is low, only reaching 82.32%, and the heating process is complicated and the temperature is high, requiring heating to above 1200°C in a tubular atmosphere furnace and above 1100°C in a microwave muffle furnace, which is not conducive to energy saving and consumption reduction. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a comprehensive utilization method for titanium-containing blast furnace slag that features low energy consumption and excellent recycling performance. To solve the above-mentioned technical problems, the technical solution of the present invention is as follows: A comprehensive utilization method for titanium-containing blast furnace slag includes the following steps: S1. Provide titanium-containing blast furnace slag with a particle size ≤100 mesh and a moisture content ≤0.5wt%; S2. Mix the titanium-containing blast furnace slag, carbonaceous reducing agent, composite phase inversion agent and water at a mass ratio of 100:25-35:40-50:20-25, granulate and dry to obtain pellets. The composite phase-transforming agent is composed of NaCl and CaCl2 in a mass ratio of 4-8:4; the carbonaceous reducing agent is composed of coke powder (i.e., coke powder) and activated carbon in a mass ratio of 5-9:3. S3. Under a protective atmosphere or vacuum, the pellets are microwave-heated to 800-1000℃ and held for 1.5-2.5 hours to obtain a mixed gas and chlorinated tailings. During microwave heating, the microwave power is controlled at 30-50kW. S4. The mixed gas is subjected to first-stage condensation separation, second-stage condensation separation, and third-stage condensation separation in sequence to obtain SiCl4 product, TiCl4 product, and iron-aluminum salt product containing FeCl3 and / or AlCl3 in sequence. The condensation temperature of the first-stage condensation separation is 136-140℃, the condensation temperature of the second-stage condensation separation is 102-105℃, and the condensation temperature of the third-stage condensation separation is 12-15℃.

[0006] In this invention, the pellets undergo drying treatment, resulting in a low moisture content. This avoids excessive water vapor generation during subsequent reactions that dilutes the mixed gas and reduces chlorination efficiency. A specific mass ratio of coke powder and activated carbon is used as a carbonaceous reducing agent, balancing reducing power and cost. Furthermore, the highly developed pore structure of activated carbon helps improve the permeability of the pellets, facilitating the rapid escape of the mixed gas generated by S3 from the pellet interior and promoting the forward chlorination reaction. The applicant's research has found that using a specific mass ratio of NaCl and CaCl2 as a composite phase-inverting agent can reduce C... The activation energy for the chlorination reaction of aTiO3 is determined by microwave assistance, which rapidly disrupts the perovskite (CaTiO3) crystal structure, allowing the reaction to proceed fully at temperatures as low as 800-1000℃ and achieving a high titanium recovery rate. Furthermore, the water-soluble composite chlorinating agent facilitates thorough and uniform mixing with titanium-containing blast furnace slag, carbonaceous reducing agents, and other raw materials during the S2 mixing process, laying the foundation for subsequent reactions. Substances containing impurities such as Fe, Al, and Si also undergo chlorination reactions with the composite phase-inversion agent to generate corresponding chlorides. Through staged condensation separation, SiCl4, TiCl4, FeCl3, and AlCl3 in the mixed gas can be separated and recovered in stages, achieving the separation and recovery of valuable elements such as silicon, titanium, iron, and aluminum.

[0007] The following chemical reactions may occur in S3: (1) Core titanium chlorination reaction (main reaction): CaTiO3+3C+2NaCl+CaCl2=TiCl4↑+ 2CaO·Na2O+3CO↑.

[0008] (2) Chlorination reaction of impurities (side reaction): 2FeO + C + 2Cl - = 2FeCl3↑ + CO↑; Al₂O₃ + 3C + 3Cl - = 2AlCl3↑ + 3CO↑; SiO2 + 2C + 2Cl - = SiCl4↑ + 2CO↑.

[0009] The reaction yields a mixed gas containing TiCl4, FeCl3, AlCl3, SiCl4, and CO. The remaining chlorinated tailings are mainly composed of 2CaO·Na2O and silicates, and contain no toxic or harmful substances. They can be directly used for further resource recovery, for example, as raw materials for preparing aggregates for building materials.

[0010] In S4, through staged condensation separation, the components in the mixed gas are precisely separated according to their boiling point differences (SiCl4 boiling point < TiCl4 boiling point < FeCl3 and AlCl3 boiling points), utilizing temperature differences to separate substances such as TiCl4. The purity of the TiCl4 product can reach over 99.2 wt%, laying the foundation for its further use in the preparation of industrial-grade titanium dioxide and other products.

[0011] Optionally, the titanium-containing blast furnace slag can be crushed by a jaw crusher, ground by a ball mill, and then dried to obtain the titanium-containing blast furnace slag with the particle size and moisture content described in S1.

[0012] Optionally, in S1, the particle size of the titanium-containing blast furnace slag is 60-80 mesh.

[0013] Furthermore, the titanium-containing blast furnace slag is the Panzhihua-Xichang high-titanium type blast furnace slag.

[0014] Optionally, the TiO2 content in the titanium-containing blast furnace slag is 20~28wt%.

[0015] Furthermore, the content of CaTiO3 in the titanium-containing blast furnace slag is 30-45 wt%.

[0016] Furthermore, in S2, the moisture content of the pellets is ≤0.3wt%, and even further, ≤0.2wt%.

[0017] Optionally, in S2, the drying temperature is 100-120℃.

[0018] Optionally, the pellet size is 3-5 mm.

[0019] Further, in S2, the titanium-containing blast furnace slag, carbonaceous reducing agent, composite phase inversion agent, and water are mixed evenly at a mass ratio of 100:28-32:42-48:21-24.

[0020] Further, in S2, the composite phase-transforming agent is composed of NaCl and CaCl2 in a mass ratio of 5-7:4; and / or, the carbonaceous reducing agent is composed of coke powder and activated carbon in a mass ratio of 6-8:3.

[0021] Further, in step S3, the pellets are microwave-heated to 850-950℃ and held at that temperature for 1.8-2.2 hours to obtain a mixed gas and chlorinated tailings. During microwave heating, the microwave power is controlled at 35-45kW. Controlling the appropriate microwave power ensures the microwave heating rate is kept within a suitable range (e.g., 15-20℃ / min), preventing localized high-temperature coking of the material.

[0022] Furthermore, in step S3, the protective atmosphere is a nitrogen atmosphere, and the nitrogen gas introduction rate is 2-3 L / min. Conducting the reaction under a protective atmosphere prevents the oxidation of raw materials and products; simultaneously, controlling the nitrogen gas introduction rate allows the mixed gas produced by the reaction to be carried away in a timely manner, further promoting the forward progress of the relevant reactions.

[0023] Furthermore, in S4, water is used as the cooling medium for the first-stage condensation separation; an aqueous solution of ethanol is used as the cooling medium for the second-stage condensation separation; and liquid nitrogen is used as the cooling medium for the third-stage condensation separation. Optionally, the concentration of the aqueous ethanol solution is 15-50 vol%. These cooling media can be recycled, which helps to save costs.

[0024] Furthermore, after S4, the TiCl4 product is oxidized at 350-400℃ in the presence of oxygen, and then calcined at 750-850℃ for 1-1.5 hours to obtain TiO2 product. Thus, a TiO2 product with a purity ≥99.5% can be obtained, meeting the standards for industrial-grade titanium dioxide.

[0025] Further, after S4, the iron-aluminum salt product is mixed with an excess of lime milk (containing Ca(OH)2) and reacted, then filtered to obtain a CaCl2 solution; the CaCl2 solution is then concentrated, crystallized, filtered, and dried sequentially to obtain a CaCl2 product; then the CaCl2 product is mixed with NaCl in a certain proportion to obtain a composite phase inversion agent, and returned to S2; The lime slurry concentration is 10-15 wt%, the reaction temperature is controlled at 50-60℃, and the reaction time is 0.5-1 h. The following reactions may occur during this process: (1) 2FeCl3+3Ca(OH)2= 2Fe(OH)3↓+ 3CaCl2; (2) 2AlCl3+3Ca(OH)2= 2Al(OH)3↓+ 3CaCl2.

[0026] The reaction produces Fe(OH)3 and Al(OH)3 precipitates and a CaCl2 solution. After filtration, the CaCl2 solution is separated. This CaCl2 solution is then concentrated, crystallized, filtered, and dried to obtain the CaCl2 product. This product is then mixed with NaCl in a specific ratio to obtain the composite phase-inversion agent, which is returned to S2. This allows for the recycling of some chlorine elements and directly produces the calcium chloride needed for the composite phase-inversion agent, effectively reducing raw material costs. Furthermore, the Fe(OH)3 and Al(OH)3 precipitates obtained from filtration can be further separated and recovered as needed.

[0027] Furthermore, after S3, the chlorinated tailings are mixed with cement and fly ash at a mass ratio of 5-7:2-4:1 and used to prepare aggregates for building materials. This helps to achieve full-scale resource utilization of titanium-containing blast furnace slag and realize zero tailings emissions.

[0028] This invention provides a microwave-assisted low-temperature chlorination method for the comprehensive utilization of titanium-containing blast furnace slag, addressing the technical pain points of existing titanium extraction processes, such as high energy consumption, significant pollution, and low titanium recovery rates. This invention mixes and granulates titanium-containing blast furnace slag with a carbonaceous reducing agent and a composite phase-transforming agent, then uses microwave heating to achieve efficient titanium chlorination at a low temperature of 800-1000℃. The generated TiCl4 and impurity chlorides are separated by staged condensation, achieving the separation and recovery of elements such as Si, Ti, Fe, and Al. Subsequently, TiCl4 can be further oxidized to prepare TiO2, and the chlorinated tailings can be directly used to prepare aggregates for building materials. This invention reduces energy consumption by more than 40%, achieves a titanium recovery rate of ≥88%, and produces no secondary pollution. It is particularly suitable for large-scale processing of high-titanium-containing blast furnace slag from industries like Panzhihua and Xichang, combining economic efficiency with energy conservation and environmental protection.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The method of the present invention significantly reduces energy consumption: by using microwave heating treatment, the chlorination temperature is only 800~1000℃, which can reduce energy consumption by more than 40% compared with the traditional high temperature carbonization process (1600~1800℃), effectively reducing the time required for heating and shortening the reaction time by more than 30%.

[0030] 2. The present invention has a high titanium recovery rate: through the synergistic effect of composite phase inversion agent and microwave heating, the titanium recovery rate is ≥88%, which far exceeds the level of 75%~80% of the traditional process. The purity of TiCl4 product is ≥99.2%, and the purity of TiO2 product obtained by further processing is ≥99.5%.

[0031] 3. This invention is more environmentally friendly: the chlorination process does not involve high-temperature carbonization, thus avoiding the formation of dioxins; the three-stage condensation separation is thorough; and the chlorination tailings can be used to prepare aggregates for building materials, achieving zero discharge of solid waste and no secondary pollution from wastewater or waste residue.

[0032] 4. The present invention is highly economical: some of the chlorine in the composite phase inversion agent can be recycled, which helps to significantly reduce raw material costs; the entire process is adaptable to large-scale production, and a single production line can process more than 100,000 tons of titanium-containing blast furnace slag per year.

[0033] 5. The method of the present invention has wide applicability, especially suitable for high-titanium blast furnace slag with TiO2 content of 20~28wt% in the Panxi region, and can also be adapted to titanium-containing blast furnace slag in other regions. It provides a brand-new technical path for the comprehensive utilization of titanium-containing blast furnace slag and has good application prospects. Attached Figure Description

[0034] Figure 1 This is a physical image of the TiO2 product obtained in Example 1 of the present invention. Detailed Implementation

[0035] The present invention will be described in detail below with reference to embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the present invention can be combined with each other. Unless otherwise specified, the relevant percentages refer to mass percentages.

[0036] Example 1 The comprehensive utilization method of titanium-containing blast furnace slag in this embodiment includes the following steps: S1. Pretreatment: Take Panzhihua high-titanium blast furnace slag with TiO2 content of 22wt% (CaTiO3 content of about 38%), crush and grind it to 80 mesh, and dry it at 130℃ to a moisture content of 0.4wt% to obtain titanium-containing blast furnace slag. S2. The titanium-containing blast furnace slag, carbonaceous reducing agent, composite phase inversion agent and water are mixed evenly in a mass ratio of 100:30:45:23, granulated by a granulator (granulation at a diameter of 3 mm), and dried at 110°C to a moisture content of 0.2 wt% to obtain pellets. The composite phase-transforming agent is composed of NaCl and CaCl2 in a mass ratio of 6:4; the carbonaceous reducing agent is composed of coke powder and activated carbon in a mass ratio of 7:3. S3. Under the condition of nitrogen gas (nitrogen gas introduction rate: 2.5L / min), the pellets are placed in an industrial microwave oven and microwave heated to 900°C. After holding at this temperature for 2 hours, a mixed gas and chlorinated tailings are obtained. During microwave heating, the microwave power is controlled at 40kW. S4. The mixed gas is subjected to first-stage condensation separation, second-stage condensation separation, and third-stage condensation separation in sequence to obtain SiCl4 product, TiCl4 product, and iron-aluminum salt product containing FeCl3 and AlCl3 in sequence. The condensation temperature for the first-stage condensation separation is 138℃, for the second-stage condensation separation it is 103℃, and for the third-stage condensation separation it is 13℃. Water is used as the cooling medium for the first-stage condensation separation; a 20 vol% aqueous solution of ethanol is used as the cooling medium for the second-stage condensation separation; and liquid nitrogen is used as the cooling medium for the third-stage condensation separation.

[0037] S5. After oxidizing the TiCl4 product at 380℃ in air, it is calcined at 800℃ for 1.2h to obtain the TiO2 product (see...). Figure 1 ); After mixing and reacting the iron-aluminum salt product with an excess of lime milk, the mixture was filtered to obtain a CaCl2 solution. The solution was then concentrated, crystallized, filtered, and dried to obtain the CaCl2 product. The CaCl2 product was then mixed with NaCl in a specific ratio to obtain a composite phase-inverting agent, which was returned to S2. The concentration of the lime milk was 13 wt%, the reaction temperature was controlled at 55℃, and the reaction time was 0.8 h. Chlorinated tailings are mixed with cement and fly ash at a mass ratio of 6:3:1 to prepare aggregates for building materials, aiming to achieve zero tailings discharge. The solid waste utilization rate of the entire process is calculated to be over 95% using the following formula: η(solid waste) = (mass of finished TiO2 product + mass of aggregate / initial mass of titanium-containing blast furnace slag) × 100%, indicating that the method of this invention has a high resource utilization rate.

[0038] The TiCl4 product was tested and found to have a purity of 99.8 wt% and a Ti recovery rate of 92.2%.

[0039] Comparative Example 1 Repeat Example 1, except that NaCl is used instead of the composite phase inversion agent.

[0040] Tests showed that the purity of the TiCl4 product was 95%, and the Ti recovery rate was 85%.

[0041] Comparative Example 2 Example 1 was repeated, except that CaCl2 was used instead of the composite phase-transfer agent.

[0042] The purity of the TiCl4 product was found to be 96.5%, and the Ti recovery rate was 86.5%.

[0043] It is evident that simply replacing the composite phase-transfer agent with sodium chloride or calcium chloride cannot achieve high TiCl4 product purity and high titanium recovery rates. This indicates that the chlorination reaction is difficult to complete under these relatively low temperature conditions.

[0044] Comparative Example 3 Repeat Example 1, except that MgCl2 is used instead of CaCl2 in the composite phase inversion agent.

[0045] Testing revealed that the purity of the TiCl4 product was 88%, and the titanium recovery rate was 80.1%.

[0046] It is evident that replacing CaCl2 in the composite phase transition agent with magnesium chloride cannot achieve high TiCl4 product purity and high titanium recovery rate. The instructions also state that using a mixture of sodium chloride and magnesium chloride as the composite phase transition agent cannot achieve complete chlorination of CaTiO3 at relatively low temperatures.

[0047] Comparative Example 4 Example 1 is repeated, except that the composite phase-transforming agent is composed of NaCl and CaCl2 in a mass ratio of 2:4.

[0048] Tests showed that the purity of the TiCl4 product was 97.2%, and the titanium recovery rate was 88.1%.

[0049] Example 2 Example 1 is repeated, except that the composite phase-transfer agent is composed of NaCl and CaCl2 in a mass ratio of 4:4.

[0050] Tests showed that the purity of the TiCl4 product was 98.1%, and the titanium recovery rate was 89.2%.

[0051] Example 3 Example 1 is repeated, except that the composite phase-transfer agent is composed of NaCl and CaCl2 in a mass ratio of 8:4.

[0052] Tests showed that the purity of the TiCl4 product was 98.8%, and the titanium recovery rate was 90.5%.

[0053] Comparative Example 5 Example 1 is repeated, except that the composite phase-transfer agent is composed of NaCl and CaCl2 in a mass ratio of 10:4.

[0054] Tests showed that the purity of the TiCl4 product was 98.2%, and the titanium recovery rate was 88.8%.

[0055] It is evident that using a composite phase-transfer agent composed of sodium chloride and calcium chloride in a specific ratio helps to obtain high purity TiCl4 products and high titanium recovery rates. This is likely because, when using the aforementioned composite phase-transfer agent, the main reaction proceeds fully, resulting in complete chlorination and phase inversion.

[0056] Example 4 Repeat Example 1, except that in step 3, the reaction is carried out at 850°C for 2 hours.

[0057] Testing revealed that the purity of the TiCl4 product was 98.5%, and the titanium recovery rate was 89.3%.

[0058] Comparative Example 6 Repeat Example 1, except that the carbonaceous reducing agent is coke powder.

[0059] Testing revealed that the purity of the TiCl4 product was 98.1%, and the titanium recovery rate was 86.1%. A possible reason is that when only coke powder is used as a carbonaceous reducing agent, the permeability of the pellets decreases, making it difficult to quickly expel the gases generated during the chlorination reaction, thus reducing the degree of completion of the related reactions.

[0060] Comparative Example 7 Example 1 is repeated, except that the carbonaceous reducing agent is activated carbon.

[0061] Testing revealed that the purity of the TiCl4 product was 98.8%, and the titanium recovery rate was 85%. A possible reason is that when activated carbon was used alone as the carbonaceous reducing agent, its reducing power was reduced, leading to a decrease in the aforementioned indicators.

[0062] Comparative Example 8 Example 1 is repeated, except that the carbonaceous reducing agent is composed of coke powder and activated carbon in a 3:3 mass ratio.

[0063] Tests showed that the purity of the TiCl4 product was 98.9%, and the titanium recovery rate was 87.6%.

[0064] Example 5 Example 1 is repeated, except that the carbonaceous reducing agent is composed of coke powder and activated carbon in a mass ratio of 5:3.

[0065] Tests showed that the purity of the TiCl4 product was 99.1%, and the titanium recovery rate was 88.7%.

[0066] Example 6 Example 1 is repeated, except that the carbonaceous reducing agent is composed of coke powder and activated carbon in a mass ratio of 9:3.

[0067] Tests showed that the purity of the TiCl4 product was 99.0%, and the titanium recovery rate was 89.9%.

[0068] Comparative Example 9 Example 1 is repeated, except that the carbonaceous reducing agent is composed of coke powder and activated carbon in a mass ratio of 11:3.

[0069] Tests showed that the purity of the TiCl4 product was 98.1%, and the titanium recovery rate was 87.1%.

[0070] The above embodiments should be understood as being used only to illustrate the present invention more clearly, and not to limit the scope of the present invention. After reading the present invention, any modifications of the present invention in various equivalent forms by those skilled in the art fall within the scope defined by the appended claims.

Claims

1. A method for the comprehensive utilization of titanium-containing blast furnace slag, characterized in that, Includes the following steps: S1. Provide titanium-containing blast furnace slag with a particle size ≤100 mesh and a moisture content ≤0.5wt%; S2. Mix the titanium-containing blast furnace slag, carbonaceous reducing agent, composite phase inversion agent and water at a mass ratio of 100:25-35:40-50:20-25, granulate and dry to obtain pellets. The composite phase-transforming agent is composed of NaCl and CaCl2 in a mass ratio of 4-8:4; the carbonaceous reducing agent is composed of coke powder and activated carbon in a mass ratio of 5-9:

3. S3. Under a protective atmosphere or vacuum, the pellets are microwave-heated to 800-1000℃ and held for 1.5-2.5 hours to obtain a mixed gas and chlorinated tailings. During microwave heating, the microwave power is controlled at 30-50kW. S4. The mixed gas is subjected to first-stage condensation separation, second-stage condensation separation, and third-stage condensation separation in sequence to obtain SiCl4 product, TiCl4 product, and iron-aluminum salt product containing FeCl3 and / or AlCl3 in sequence. The condensation temperature of the first-stage condensation separation is 136-140℃, the condensation temperature of the second-stage condensation separation is 102-105℃, and the condensation temperature of the third-stage condensation separation is 12-15℃.

2. The comprehensive utilization method according to claim 1, characterized in that, The content of CaTiO3 in the titanium-containing blast furnace slag is 30-45 wt%.

3. The comprehensive utilization method according to claim 1, characterized in that, In S2, the titanium-containing blast furnace slag, carbonaceous reducing agent, composite phase inversion agent, and water are mixed evenly at a mass ratio of 100:28-32:42-48:21-24.

4. The comprehensive utilization method according to claim 1, characterized in that, In S2, the composite phase-transforming agent is composed of NaCl and CaCl2 in a mass ratio of 5-7:4; and / or, the carbonaceous reducing agent is composed of coke powder and activated carbon in a mass ratio of 6-8:

3.

5. The comprehensive utilization method according to claim 1, characterized in that, In step S3, the pellets are microwave-heated to 850-950℃ and held at that temperature for 1.8-2.2 hours to obtain a mixed gas and chlorinated tailings; wherein, during microwave heating, the microwave power is controlled to be 35-45kW.

6. The comprehensive utilization method according to any one of claims 1-5, characterized in that, In S3, the protective atmosphere is a nitrogen atmosphere, and the nitrogen introduction rate is 2~3 L / min.

7. The comprehensive utilization method according to any one of claims 1-5, characterized in that, In S4, water is used as the cooling medium for the first-stage condensation separation; an aqueous solution of ethanol is used as the cooling medium for the second-stage condensation separation; and liquid nitrogen is used as the cooling medium for the third-stage condensation separation.

8. The comprehensive utilization method according to any one of claims 1-5, characterized in that, After S4, the TiCl4 product is oxidized at 350-400℃ in the presence of oxygen, and then calcined at 750-850℃ for 1-1.5h to obtain the TiO2 product.

9. The comprehensive utilization method according to any one of claims 1-5, characterized in that, After S4, the iron-aluminum salt product is mixed with an excess of lime milk and reacted, then filtered to obtain a CaCl2 solution; the CaCl2 solution is then concentrated, crystallized, filtered, and dried to obtain a CaCl2 product; the CaCl2 product is then mixed with NaCl in a certain proportion to obtain a composite phase inversion agent, which is returned to S2. The concentration of lime slurry is 10-15 wt%, the reaction temperature is controlled at 50-60℃, and the reaction time is 0.5-1h.

10. The comprehensive utilization method according to any one of claims 1-5, characterized in that, After S3, the chlorinated tailings are mixed with cement and fly ash at a mass ratio of 5-7:2-4:1 and used to prepare aggregates for building materials.

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