Method for extracting titanium and removing chlorine through high-temperature carbonization-selective chlorination of vanadium-titanium slag and fly ash

Abstract

The invention provides a high-temperature carbonization-selective chlorination titanium extraction and dechlorination method for vanadium-titanium slag and fly ash, and relates to the technical field of solid waste treatment. The high-temperature carbonization-selective chlorination titanium extraction and dechlorination method for the vanadium-titanium slag and the fly ash comprises the following steps: uniformly mixing the activated vanadium-titanium slag with the fly ash, an auxiliary material and dry carbon powder to obtain a mixed material, carrying out high-temperature heat treatment, and recovering high-temperature heat treatment reaction flue gas to obtain titanium tetrachloride. The invention provides a method for extracting titanium and removing chlorine by high-temperature carbonization-selective chlorination of vanadium-titanium slag and fly ash, which comprises the following steps: by taking two waste residues of vanadium-titanium slag and fly ash as reaction raw materials, fully utilizing chlorine in the fly ash as a chlorine source for extracting titanium in the vanadium-titanium slag in a chlorination volatilization process through the synergistic effect of specific compatibility of the reaction materials and high-temperature heat treatment conditions; in the high-temperature chloridizing volatilization process, chloridizing volatilization of titanium, synergistic detoxification of dioxin, volatilization of volatile heavy metal and solidification and stabilization of residual heavy metal are achieved.

Description

Technical Field

[0001] This invention relates to the field of solid waste treatment technology, and in particular to a method for high-temperature carbonization-selective chlorination of vanadium-titanium slag and fly ash to extract titanium and remove chlorine. Background Technology

[0002] With the development of the steel industry, vanadium-titanium magnetite is used as raw material for blast furnace smelting and converter smelting, generating vanadium-titanium slag as a byproduct. The annual vanadium-titanium content of this slag is constantly increasing. Currently, the large accumulation of vanadium-titanium slag often involves vanadium extraction, but the recovery rate of titanium resources is insufficient. Open-air accumulation of vanadium-titanium slag easily leads to dust pollution and heavy metal leakage. Municipal solid waste incineration fly ash (hereinafter referred to as fly ash) is particulate matter captured by flue gas purification systems (such as bag filters and electrostatic precipitators) during the municipal solid waste incineration power generation process. It is a residue after incineration flue gas treatment. According to the "National Hazardous Waste List (2021 Edition)," fly ash is explicitly listed as hazardous waste due to its toxic substances (heavy metals, dioxins, etc.) and must be strictly disposed of according to hazardous waste standards. Chlorine in fly ash can affect its subsequent utilization. Taking building materials utilization as an example, the chlorine content in fly ash is generally as high as 15% to 20% (mainly soluble chloride salts), far exceeding the standard for chloride ion content in cement (≤0.06%). To broaden the utilization of fly ash, it is necessary to remove chlorine and detoxify it.

[0003] Currently, there are numerous methods for extracting titanium from vanadium-titanium slag and for dechlorinating and detoxifying fly ash. However, each method has its own problems and cannot achieve good synergistic treatment effects between vanadium-titanium slag and fly ash, especially in achieving good synergistic effects in titanium chlorination volatilization, dioxin synergistic detoxification, volatilization of volatile heavy metals, and solidification and stabilization of residual heavy metals. Existing technology CN 112275783A discloses a fly ash detoxification treatment method and equipment. The fly ash detoxification treatment method includes: mixing fly ash and biogas residue evenly and forcibly stirring to obtain a premixed slurry; heating and stirring the premixed slurry at 100-180℃ for 0.5-1h under closed conditions to obtain a heated slurry; separating the heated slurry into liquid and solid; treating the liquid as wastewater to meet standards before discharge; pyrolyzing the solid at 400-600℃ to obtain pyrolysis residue, which is either used as solid waste for landfill or as an inorganic material for preparing ceramics or sintered bricks. The existing technology can achieve fly ash detoxification, heavy metal stabilization and solidification and dioxin elimination, but it does not synergistically treat vanadium-titanium slag, and cannot achieve synergistic detoxification treatment of the two major solid wastes, vanadium-titanium slag and fly ash. Summary of the Invention

[0004] This invention addresses the shortcomings of existing solid waste treatment methods that lack synergistic detoxification approaches for vanadium-titanium slag and fly ash. It provides a high-temperature carbonization-selective chlorination method for titanium extraction and dechlorination of vanadium-titanium slag and fly ash. Through a "waste-to-waste" approach, the chlorine element in fly ash is transformed into a driving force for titanium extraction from vanadium-titanium slag, simultaneously solving the problems of fly ash dechlorination, heavy metal and dioxin detoxification, and titanium resource recovery. This method exhibits technological synergy. The residue from the synergistic treatment of vanadium-titanium slag and fly ash can be used for the preparation of solid waste cementitious materials and the development of functional materials, broadening the subsequent utilization pathways of vanadium-titanium slag and fly ash, and providing a new path for the high-value utilization of hazardous waste and metallurgical slag.

[0005] This invention provides a method for high-temperature carbonization and selective chlorination of vanadium-titanium slag and fly ash to extract titanium and remove chlorine, comprising the following steps: The activated vanadium-titanium slag is mixed with fly ash, auxiliary materials and dry carbon powder to obtain a mixture, which is then subjected to high-temperature heat treatment. The high-temperature heat treatment reaction flue gas is recovered to obtain titanium tetrachloride. The amount of auxiliary materials added in the mixture is 0.001~15wt%, the molar ratio of titanium to carbon in the activated vanadium-titanium slag is (0.15~2):1, and the molar ratio of titanium to chlorine in the activated vanadium-titanium slag is 1:(2.5~6.5). The high-temperature heat treatment temperature is 500~1300℃, and the high-temperature heat treatment time is 1~600min.

[0006] According to the present invention, a method for high-temperature carbonization-selective chlorination of vanadium-titanium slag and fly ash to extract titanium and remove chlorine is provided. Preferably, the molar ratio of titanium element in the activated vanadium-titanium slag to carbon element in the dry carbon powder is (0.2~1.5):1.

[0007] According to the present invention, a method for high-temperature carbonization-selective chlorination of vanadium-titanium slag and fly ash to extract titanium and remove chlorine is provided. Preferably, the molar ratio of titanium in the activated vanadium-titanium slag to chlorine in the fly ash is 1:(3~4.5).

[0008] According to the present invention, a method for high-temperature carbonization-selective chlorination of vanadium-titanium slag and fly ash to extract titanium and remove chlorine is provided. Preferably, the high-temperature heat treatment temperature is 800~1200℃ and the high-temperature heat treatment time is 1~100min, preferably 15~30min.

[0009] According to the present invention, a method for high-temperature carbonization-selective chlorination of vanadium-titanium slag and fly ash to extract titanium and remove chlorine is provided. Preferably, the amount of auxiliary material added in the mixture is 0.001~10wt%, more preferably 0.05~5wt%.

[0010] According to the present invention, a method for high-temperature carbonization-selective chlorination of vanadium-titanium slag and fly ash to extract titanium and remove chlorine is provided. Preferably, the auxiliary materials are selected from any one or more of calcium chloride, calcium hydroxide, calcium oxide, carbide slag, calcium fluoride, quartz sand, sandstone, fly ash, mineral powder, glass powder, chlorinated organic matter, chlorinated organic plastics, and chlorinated waste from chemical enterprises.

[0011] According to the present invention, a method for high-temperature carbonization-selective chlorination of vanadium-titanium slag and fly ash to extract titanium and remove chlorine is provided. Preferably, the auxiliary material is a mixture of calcium chloride and calcium fluoride, and the preferred mixing ratio is (1~2):(1~3).

[0012] According to the present invention, a method for high-temperature carbonization-selective chlorination of vanadium-titanium slag and fly ash to extract titanium and remove chlorine is provided. Preferably, the vanadium-titanium slag is activated by the following method: crushed vanadium-titanium slag, activating agent and remixed material are mixed, ground and sieved to obtain solid material, wherein the particle size of the solid material is ≤0.10 cm.

[0013] According to the present invention, a method for high-temperature carbonization-selective chlorination of vanadium-titanium slag and fly ash to extract titanium and remove chlorine is provided. Preferably, the activating agent is selected from one or more of organic chelating agents, inorganic chelating agents, organic acids and elemental metals.

[0014] According to the present invention, a method for high-temperature carbonization-selective chlorination of vanadium-titanium slag and fly ash to extract titanium and remove chlorine is provided. Preferably, the amount of activating agent added during the grinding is 0.001~10wt% of the total mass of the crushed vanadium-titanium slag, activating agent and backmixed material.

[0015] According to the present invention, a method for high-temperature carbonization-selective chlorination of vanadium-titanium slag and fly ash to extract titanium and remove chlorine is provided. Preferably, the fly ash is municipal solid waste incineration fly ash with a chlorine content of 10-20 wt%. And / or, the titanium content in the vanadium-titanium slag is not less than 10% (calculated as TiO2).

[0016] Beneficial effects: This invention provides a method for high-temperature carbonization and selective chlorination of vanadium-titanium slag and fly ash to extract titanium and remove chlorine. Using vanadium-titanium slag and fly ash as two major waste residues as reaction raw materials, the method fully utilizes the chlorine in fly ash as the chlorine source for extracting titanium from vanadium-titanium slag through the synergistic effect of specific compatibility of reactants and high-temperature heat treatment conditions. During the high-temperature chlorination and volatilization process, the method achieves the volatilization of titanium chlorination, the synergistic detoxification of dioxins, the volatilization of volatile heavy metals, and the solidification and stabilization of residual heavy metals. Attached Figure Description

[0017] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0018] Figure 1 The process flow diagram of the high-temperature carbonization-selective chlorination method for titanium extraction and dechlorination of vanadium-titanium slag and fly ash provided by the present invention is shown. Detailed Implementation

[0019] The following examples are for illustrative purposes only and are not intended to limit the scope of the invention. Where specific techniques or conditions are not specified in the examples, they should be performed according to the techniques or conditions described in the literature in this field, or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased through legitimate channels.

[0020] In a specific embodiment, the present invention provides a method for high-temperature carbonization and selective chlorination of vanadium-titanium slag and fly ash to extract titanium and remove chlorine, comprising the following steps: The sieved solid material (vanadium-titanium slag solid after grinding and activation sieving) is mixed with fly ash, auxiliary materials and dry charcoal powder to obtain a mixture, which is then subjected to high-temperature heat treatment to recover the high-temperature heat treatment reaction flue gas to obtain titanium tetrachloride; the amount of auxiliary materials added in the mixture is 0.001~15wt%, the molar ratio of titanium element in the solid material to carbon element in the dry charcoal powder is (0.15~2):1, and the molar ratio of titanium element in the solid material to chlorine element in the fly ash is 1:(2.5~6.5); The high-temperature heat treatment temperature is 500~1300℃, and the high-temperature heat treatment time is 1~600min.

[0021] It should be noted that: The auxiliary materials mentioned in this invention serve to provide a chlorine source or to assist in the activation of vanadium-titanium slag. The dry carbon powder serves to carbonize and reduce the titanium-containing components in the vanadium-titanium slag under high-temperature conditions. The addition of both will promote the chemical transformation of titanium in the vanadium-titanium slag.

[0022] In the high-temperature carbonization-selective chlorination method for titanium extraction and dechlorination of vanadium-titanium slag and fly ash provided by this invention, by controlling the composition and material ratio of the mixture under high-temperature heat treatment, especially the synergistic control of the molar ratio of titanium in solid materials to carbon in dry carbon powder, and the specific high-temperature heat treatment temperature and time, the synthesis of titanium tetrachloride can be effectively promoted. This not only achieves efficient recovery of titanium from vanadium-titanium slag, but also makes full use of the chlorine resources in fly ash.

[0023] The present invention provides a method for high-temperature carbonization-selective chlorination of vanadium-titanium slag and fly ash to extract titanium and remove chlorine. This method is a synergistic coupling method for the chlorination extraction of titanium from vanadium-titanium slag and the dechlorination and detoxification of municipal solid waste incineration fly ash. Vanadium-titanium slag and fly ash are two types of large-scale solid waste. Co-processing these two types of waste can achieve the effect of "treating waste with waste". It makes full use of the chlorine in fly ash as the chlorine source for extracting titanium from vanadium-titanium slag during the chlorination volatilization process. During the high-temperature carbonization chlorination volatilization process, the chlorination volatilization of titanium in vanadium-titanium slag is achieved, along with the synergistic detoxification of dioxins in fly ash, the volatilization of volatile heavy metals, and the solidification and stabilization of residual heavy metals. The combined chlorination volatilization treatment of the two wastes can achieve dechlorination and detoxification of fly ash and extraction of valuable metals from vanadium-titanium slag. The utilization pathways of the residue after synergistic treatment are also broadened.

[0024] In some specific embodiments, in order to achieve a good carbonization effect of dry carbon powder on the titanium-containing components in vanadium-titanium slag under high temperature conditions, the present invention further preferably uses a molar ratio of titanium element in the solid material to carbon element in the dry carbon powder of (0.2~1.5):1. For example, the molar ratio of titanium element in the solid material to carbon element in the dry carbon powder can be a point value or any range of values ​​such as 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1.0:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1 or 1.5:1.

[0025] In some specific embodiments, in order to achieve the effect of chlorine in fly ash on the volatilization of titanium chlorination in vanadium-titanium after high-temperature carbonization, the present invention further preferably uses a molar ratio of titanium in the solid material to chlorine in the fly ash of 1:(3~4.5). For example, the molar ratio of titanium in the solid material to chlorine in the fly ash can be a point value or any range of values ​​such as 1:3.0, 1:3.1, 1:3.2, 1:3.3, 1:3.4, 1:3.5, 1:3.6, 1:3.7, 1:3.8, 1:3.9, 1:40, 1:4.1, 1:4.2, 1:4.3, 1:4.4, 1:4.5.

[0026] In some specific embodiments, to better achieve the effect of temperature on heat treatment, the present invention further preferably uses a high-temperature heat treatment temperature of 800~1200℃ and a high-temperature heat treatment time of 1~100min. For example, the high-temperature heat treatment temperature of the present invention can be a point value or any range of 800℃, 850℃, 900℃, 950℃, 1000℃, 1050℃, 1100℃, 1150℃ or 1200℃, and the high-temperature heat treatment time can be a point value or any range of 1min, 5min, 10min, 20min, 30min, 40min, 50min, 60min, 70min, 80min, 90min or 100min, preferably 15~30min.

[0027] In some specific embodiments, the present invention further controls the amount of auxiliary materials added in the mixture to be 0.001~10wt%, for example, it can be 0.001wt%, 0.005wt%, 0.008wt%, 0.012wt%, 0.015wt%, 0.020wt%, 0.030wt%, 0.050wt%, 0.080wt%, 0.1wt%, 0.3wt%, 0.5wt%, 0.8wt%, 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 0.8wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, etc., or any range of values, preferably 0.05~5wt%.

[0028] This invention does not specifically limit the auxiliary materials. Any type of auxiliary material that can be used to achieve high-temperature carbonization-selective chlorination treatment of vanadium-titanium slag and fly ash can be used. In some specific embodiments, the auxiliary materials include any one or more of calcium chloride, calcium hydroxide, calcium oxide, carbide slag, calcium fluoride, quartz sand, sandstone, fly ash, mineral powder, glass powder, chlorinated organic matter, chlorinated organic plastics, and chlorinated waste from chemical enterprises.

[0029] In some specific embodiments, the auxiliary material is a mixture of calcium chloride and calcium fluoride, preferably in a mixing ratio of (1~2):(1~3), such as 1:1, 2:1, 1:3, etc.

[0030] In the high-temperature carbonization-selective chlorination method for titanium extraction and dechlorination of vanadium-titanium slag and fly ash of the present invention, no specific activation method for the vanadium-titanium slag is limited. Any activation method known in the art that can promote the generation and separation of titanium-containing substances can be used for treatment. Preferably, the vanadium-titanium slag is activated by the following method: The crushed vanadium-titanium slag, activating agent and remixed material are mixed, ground and screened to obtain solid material. The particle size of the solid material is ≤0.10 cm. The amount of activating agent added is 0.001~10 wt% of the total mass of the crushed vanadium-titanium slag, activating agent and remixed material.

[0031] The remixed material described in this invention consists of coarse particles with a particle size greater than 0.10 cm after subsequent screening and some solid particles removed from the recovered titanium tetrachloride-containing flue gas.

[0032] The mixing and grinding process can activate vanadium-titanium slag under the action of activating agents, and can obtain fine vanadium-titanium slag particles that meet the particle size requirements to enter the material compatibility and mixing process, resulting in a mixture before high-temperature heat treatment.

[0033] By combining activating agents with grinding treatment, the crystal structure of ilmenite can be disrupted, enhancing its reactivity. Combined with the development of targeted activating agents, efficient dissociation and fine separation of micro-particle ilmenite can be achieved, which is more conducive to subsequent titanium resource extraction. Simultaneously, controlling the particle size of solid materials to ≤0.10 cm further ensures thorough mixing of activated vanadium-titanium slag with fly ash, auxiliary materials, and dry carbon powder, increasing the reaction contact area and improving the high-temperature heat treatment effect.

[0034] In some specific embodiments, the present invention further controls the amount of activating agent added to the solid material to be 0.001~10wt%, for example, it can be a point value or any range of values ​​such as 0.001wt%, 0.005wt%, 0.008wt%, 0.012wt%, 0.015wt%, 0.020wt%, 0.030wt%, 0.050wt%, 0.080wt%, 0.1wt%, 0.3wt%, 0.5wt%, 0.8wt%, 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 0.8wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%.

[0035] In some specific embodiments, the activating agents mentioned in this invention include one or more mixtures of organic chelating agents, inorganic chelating agents, organic acids, and elemental metals.

[0036] The organic chelating agent mentioned in this invention may include any one or more of ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, hydroxyethylethylenediaminetriacetic acid, and hydroxamic acid.

[0037] The inorganic chelating agent mentioned in this invention can be, for example, a polyphosphate.

[0038] The organic acids mentioned in this invention may include any one or more of carboxylic acids, sulfonic acids, sulfinic acids, salicylic acid, hydroxamic acid, etc.

[0039] The metallic element mentioned in this invention can be iron, aluminum, etc.

[0040] Organic chelating agents can activate titanium-containing components and allow them to fully contact the titanium components in vanadium-titanium slag, thus playing a role as dry carbon powder in the subsequent high-temperature carbonization process.

[0041] In some specific embodiments, the present invention can also perform high-temperature carbonization-selective chlorination treatment on fly ash and vanadium-titanium slag, which are difficult to process, to remove chlorine and extract titanium. The fly ash mentioned is municipal solid waste incineration fly ash with a chlorine content of 10-20 wt%. The titanium content in the vanadium-titanium slag mentioned in this invention is not less than 10% (calculated as TiO2).

[0042] The high-temperature carbonization-selective chlorination method for titanium extraction and dechlorination of vanadium-titanium slag and fly ash provided by this invention has a good synergistic effect on titanium extraction and dechlorination for both fly ash with a high chlorine content of 10-20 wt% and vanadium-titanium slag with a titanium content of not less than 10% (calculated as TiO2).

[0043] The vanadium-titanium slag provided in the embodiments and comparative examples of the present invention is vanadium-titanium slag produced by steel enterprises, and the titanium content in the vanadium-titanium slag is not less than 10% (calculated as TiO2).

[0044] The fly ash provided in the embodiments and comparative examples of the present invention is municipal solid waste incineration fly ash with a chlorine content of 11.71 wt%.

[0045] The fly ash used in Embodiments 1-4 of the present invention is described as follows: Fly ash sample composition analysis table sample LOSS <![CDATA[Si02]]> <![CDATA[A1203]]> <![CDATA[Fe203]]> Ca0 <![CDATA[K20]]> <![CDATA[Na20]]> <![CDATA[Cl - ]]> Original Gray 1 10.11 10.42 4.22 1.55 33.30 3.50 2.82 10.39 Original Gray 2 15.35 9.27 3.84 1.26 31.66 3.20 6.77 12.68 Original Gray 3 19.85 10.04 4.33 1.36 32.51 3.79 2.80 12.07 average 15.10 9.91 4.13 1.39 32.49 3.50 4.13 11.71 Example 1 A method for high-temperature carbonization and selective chlorination of vanadium-titanium slag and fly ash to extract titanium and remove chlorine, such as... Figure 1 The process shown includes the following steps: The vanadium-titanium slag produced by steel enterprises is dried, and then crushed and ground sequentially. The ground material (composed of vanadium-titanium slag, activating reagent, coarse particles with a particle size greater than 0.10 cm that are subsequently screened, and some solid particles removed from the recovered titanium tetrachloride-containing flue gas) is screened. Coarse particles with a particle size greater than 0.10 cm are transferred to the grinding process for further grinding, while fine particles with a particle size less than 0.10 cm are referred to as solid material and enter the subsequent mixing and homogenization process.

[0046] The activating agent added during the grinding process is citric acid, and the addition ratio is 0.05% of the total mass of the material during the grinding process (including vanadium-titanium slag, activating agent, coarse particles with a particle size greater than 0.10 cm after subsequent screening, and some solid particles removed from the recovered titanium tetrachloride flue gas).

[0047] The sieved solid materials, dry charcoal powder, municipal solid waste incineration fly ash and auxiliary materials are mixed to obtain a mixture, which is then subjected to high-temperature heat treatment. The dry charcoal powder is coal powder, and the auxiliary materials are a mixture of calcium chloride and calcium fluoride, with a mixing mass ratio of calcium chloride to calcium fluoride of 1:1.

[0048] The proportion of auxiliary materials added is 5% of the mass of the mixture. The molar ratio of titanium in the solid material to carbon in the dry charcoal powder is 0.3:1, and the molar ratio of titanium in the solid material to chlorine in the fly ash from municipal solid waste incineration is 1:3.5.

[0049] The high-temperature heat treatment temperature is 850℃, the heating time is 30 minutes, and the gas atmosphere is air. After dust collection from the mixed flue gas containing titanium tetrachloride, titanium tetrachloride is subsequently recovered.

[0050] The titanium volatilization rate in the vanadium-titanium slag is 60%, calculated using the following formula: Where a is the mass fraction (%) of titanium in the mixture before heat treatment, m1 is the total mass (g or kg) of the mixture before heat treatment; b is the mass fraction (%) of titanium in the material after heat treatment, and m2 is the total mass (g or kg) of the material after heat treatment.

[0051] After heat treatment, the soluble chlorine content in the material shall not exceed 2%, the total dioxin residue shall be ≤50 ng-TEQ / kg, and the heavy metal leaching concentration shall meet the limit requirements in the "Identification Standard for Hazardous Waste: Leaching Toxicity Identification" (GB 5085.3).

[0052] Example 2 A method for high-temperature carbonization and selective chlorination of vanadium-titanium slag and fly ash to extract titanium and remove chlorine, such as... Figure 1 The process shown includes the following steps: The vanadium-titanium slag produced by steel enterprises is dried, and then crushed and ground sequentially. The ground material (composed of vanadium-titanium slag, activating reagent, coarse particles with a particle size greater than 0.10 cm that are subsequently screened, and some solid particles removed from the recovered titanium tetrachloride-containing flue gas) is screened. Coarse particles with a particle size greater than 0.10 cm are transferred to the grinding process for further grinding, while fine particles with a particle size less than 0.10 cm are referred to as solid material and enter the subsequent mixing and homogenization process.

[0053] The activating agent added during the grinding process is ethylenediaminetetraacetic acid (EDTA), and the addition ratio is 0.1% of the total mass of the grinding process (including vanadium-titanium slag, activating agent, coarse particles with a particle size greater than 0.10 cm after subsequent screening, and some solid particles removed from the recovered titanium tetrachloride flue gas).

[0054] The sieved solid materials, dry charcoal powder, municipal solid waste incineration fly ash, and auxiliary materials are mixed to obtain a mixture, which is then subjected to high-temperature heat treatment. The dry charcoal powder is coal powder, and the auxiliary materials are a mixture of calcium chloride and calcium fluoride, with a mass ratio of calcium chloride to calcium fluoride of 2:1.

[0055] The proportion of auxiliary materials added is 0.05% of the mass of the mixture. The molar ratio of titanium in the solid material to carbon in the dry charcoal powder is 0.5:1, and the molar ratio of titanium in the solid material to chlorine in the fly ash from municipal solid waste incineration is 1:4.1.

[0056] The high-temperature heat treatment temperature is 950℃, the heating time is 25 minutes, and the gas atmosphere is air. After dust collection from the mixed flue gas containing titanium tetrachloride, titanium tetrachloride is subsequently recovered.

[0057] The titanium recovery rate in the vanadium-titanium slag was 68%. The soluble chlorine content in the solid material after heat treatment shall not exceed 2%, the total dioxin residue shall be ≤50 ng-TEQ / kg, and the heavy metal leaching concentration shall meet the limit requirements in the "Identification Standard for Hazardous Waste: Leaching Toxicity Identification" (GB 5085.3).

[0058] Example 3 A method for high-temperature carbonization and selective chlorination of vanadium-titanium slag and fly ash to extract titanium and remove chlorine, such as... Figure 1 The process shown includes the following steps: The vanadium-titanium slag produced by steel enterprises is dried, and then crushed and ground sequentially. The ground material (composed of vanadium-titanium slag, activating reagent, coarse particles with a particle size greater than 0.10 cm that are subsequently screened, and some solid particles removed from the recovered titanium tetrachloride-containing flue gas) is screened. Coarse particles with a particle size greater than 0.10 cm are transferred to the grinding process for further grinding, while fine particles with a particle size less than 0.10 cm are referred to as solid material and enter the subsequent mixing and homogenization process.

[0059] The activating agent added during the grinding process is elemental aluminum, and the addition ratio is 0.1% of the total mass of the material during the grinding process (including vanadium-titanium slag, activating agent, coarse particles with a particle size greater than 0.10 cm after subsequent screening, and some solid particles removed from the recovered titanium tetrachloride flue gas).

[0060] The sieved solid materials, dry charcoal powder, municipal solid waste incineration fly ash, and auxiliary materials are mixed to obtain a mixture, which is then subjected to high-temperature heat treatment. The dry charcoal powder is coal powder, and the auxiliary materials are a mixture of calcium chloride and calcium fluoride, with a mixing mass ratio of calcium chloride to calcium fluoride of 1:3.

[0061] The proportion of auxiliary materials added is 0.05% of the mass of the mixture. The molar ratio of titanium in the solid material to carbon in the dry charcoal powder is 0.8:1, and the molar ratio of titanium in the solid material to chlorine in the fly ash from municipal solid waste incineration is 1:4.5.

[0062] The high-temperature heat treatment temperature is 1100℃, the heating time is 15 minutes, and the gas atmosphere is air. After the mixed flue gas containing titanium tetrachloride is treated with a dust collection process, titanium tetrachloride is then recovered.

[0063] The titanium recovery rate in vanadium-titanium slag is 72%.

[0064] The soluble chlorine content in the solid material after heat treatment shall not exceed 2%, the total dioxin residue shall be ≤50 ng-TEQ / kg, and the heavy metal leaching concentration shall meet the limit requirements in the "Identification Standard for Hazardous Waste: Leaching Toxicity Identification" (GB 5085.3).

[0065] Example 4 A method for high-temperature carbonization and selective chlorination of vanadium-titanium slag and fly ash to extract titanium and remove chlorine, such as... Figure 1 The process shown includes the following steps: The vanadium-titanium slag produced by steel enterprises is dried, and then crushed and ground sequentially. The ground material (composed of vanadium-titanium slag, activating reagent, coarse particles larger than 0.10 cm that are subsequently screened, and some solid particles removed from the recovered titanium tetrachloride-containing flue gas) is screened. Coarse particles larger than 0.10 cm are transferred to the grinding process for further grinding, while fine particles smaller than 0.10 cm are referred to as solid material and enter the subsequent mixing and homogenization process.

[0066] The activating agent added during the grinding process is elemental iron, and the addition ratio is 0.1% of the total mass of the material during the grinding process (including vanadium-titanium slag, activating agent, coarse particles with a particle size greater than 0.10 cm after subsequent screening, and some solid particles removed from the recovered titanium tetrachloride flue gas).

[0067] The sieved solid materials, dry charcoal powder, municipal solid waste incineration fly ash and auxiliary materials are mixed to obtain a mixture, which is then subjected to high-temperature heat treatment. The dry charcoal powder is coal powder, and the auxiliary materials are a mixture of calcium chloride and calcium fluoride, with a mass ratio of calcium chloride to calcium fluoride of 2:1.

[0068] The proportion of auxiliary materials added is 2% of the mass of the mixture. The molar ratio of titanium in the solid material to carbon in the dry charcoal powder is 1:1, and the molar ratio of titanium in the solid material to chlorine in the fly ash from municipal solid waste incineration is 1:3.8.

[0069] The high-temperature heat treatment temperature is 1200℃, the heating time is 20 minutes, and the gas atmosphere is air. After the mixed flue gas containing titanium tetrachloride is treated with a dust collection process, titanium tetrachloride is then recovered.

[0070] The titanium recovery rate in vanadium-titanium slag is 75%.

[0071] The soluble chlorine content in the solid material after heat treatment shall not exceed 2%, the total dioxin residue shall be ≤50 ng-TEQ / kg, and the heavy metal leaching concentration shall meet the limit requirements in the "Identification Standard for Hazardous Waste: Leaching Toxicity Identification" (GB 5085.3).

[0072] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for high-temperature carbonization-selective chlorination of vanadium-titanium slag and fly ash to extract titanium and remove chlorine, characterized in that, Includes the following steps: The activated vanadium-titanium slag is mixed with fly ash, auxiliary materials and dry carbon powder to obtain a mixture, which is then subjected to high-temperature heat treatment. The high-temperature heat treatment reaction flue gas is recovered to obtain titanium tetrachloride. The amount of auxiliary materials added in the mixture is 0.001~15wt%, the molar ratio of titanium to carbon in the activated vanadium-titanium slag is (0.15~2):1, and the molar ratio of titanium to chlorine in the activated vanadium-titanium slag is 1:(2.5~6.5). The high-temperature heat treatment temperature is 500~1300℃, and the high-temperature heat treatment time is 1~600min.

2. The method for high-temperature carbonization-selective chlorination of vanadium-titanium slag and fly ash to extract titanium and remove chlorine according to claim 1, characterized in that, The molar ratio of titanium to carbon in the activated vanadium-titanium slag is (0.2~1.5):

1.

3. The method for high-temperature carbonization-selective chlorination of vanadium-titanium slag and fly ash to extract titanium and remove chlorine according to claim 1 or 2, characterized in that, The molar ratio of titanium to chlorine in the activated vanadium-titanium slag is 1:(3~4.5).

4. The method for high-temperature carbonization-selective chlorination of vanadium-titanium slag and fly ash to extract titanium and remove chlorine according to any one of claims 1 to 3, characterized in that, The high-temperature heat treatment temperature is 800~1200℃, and the high-temperature heat treatment time is 1~100min, preferably 15~30min.

5. The method for high-temperature carbonization-selective chlorination of vanadium-titanium slag and fly ash to extract titanium and remove chlorine according to any one of claims 1 to 4, characterized in that, The amount of auxiliary materials added in the mixture is 0.001~10wt%, preferably 0.05~5wt%.

6. The method for high-temperature carbonization-selective chlorination of vanadium-titanium slag and fly ash to extract titanium and remove chlorine according to any one of claims 1 to 5, characterized in that, The auxiliary materials are selected from any one or more of the following: calcium chloride, calcium hydroxide, calcium oxide, carbide slag, calcium fluoride, quartz sand, sandstone, fly ash, mineral powder, glass powder, chlorinated organic matter, chlorinated organic plastics, and chlorinated waste from chemical enterprises.

7. The method for high-temperature carbonization-selective chlorination of vanadium-titanium slag and fly ash to extract titanium and remove chlorine according to claim 6, characterized in that, The auxiliary material is a mixture of calcium chloride and calcium fluoride, preferably in a mixing ratio of (1~2):(1~3).

8. The method for high-temperature carbonization-selective chlorination of vanadium-titanium slag and fly ash to extract titanium and remove chlorine according to any one of claims 1 to 6, characterized in that, The vanadium-titanium slag is activated by the following method: the crushed vanadium-titanium slag, activating agent and remixed material are mixed, ground and sieved to obtain solid material, which is the activated vanadium-titanium slag. The particle size of the solid material is ≤0.10 cm.

9. The method for high-temperature carbonization-selective chlorination of vanadium-titanium slag and fly ash to extract titanium and remove chlorine according to claim 8, characterized in that, The amount of activating agent added during the grinding process is 0.001~10wt% of the total mass of the crushed vanadium-titanium slag, activating agent, and remixed material.

10. The method for high-temperature carbonization-selective chlorination of vanadium-titanium slag and fly ash for titanium extraction and dechlorination according to any one of claims 1 to 9, characterized in that, The fly ash is from municipal solid waste incineration, with a chlorine content of 10-20 wt%. And / or, the titanium content of the vanadium-titanium slag is not less than 10% (calculated as TiO2).

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