A method for producing titanium tetrachloride by large-scale molten salt chlorination

Abstract

The present invention discloses a method for producing titanium tetrachloride by large-scale molten salt chlorination, 1) a mixture of high titanium slag, sodium chloride and petroleum coke is delivered to a chlorination furnace through a spiral feeder; 2) chlorine is delivered to the bottom of the molten salt in the chlorination furnace through a chlorine spray gun; 3) the chlorination furnace is sprayed with leaching mud for temperature control; 4) the gas pipe of the chlorination furnace is connected to a gas-solid separation device at 14 to 16 m; 5) the direct condensation stage is to spray the dust-collected furnace gas with the crude titanium tetrachloride slurry sprayed by the leaching device; 6) the indirect condensation stage is to condense the furnace gas that has completed direct condensation through a condensation device; 7) refined titanium tetrachloride is obtained; the present invention increases the molten salt chlorination capacity by expanding the chlorination furnace, improves the process control conditions, and reduces its control difficulty. A method for controlling production and improving the chlorination rate is proposed for large-scale chlorination furnaces to meet the needs of the production of later-stage products and avoid the shortcomings of molten salt chlorination.

Description

Technical Field

[0001] The invention relates to the technical field of inorganic chemical industry, and in particular to a method for producing titanium tetrachloride by chlorination of large-scale molten salt. Background Art

[0002] TiCl4 is the raw material for producing titanium sponge, titanium dioxide and nano-TiO2, and is also the most basic material in titanium-related industries. The main methods for industrial preparation of TiCl4 are boiling chlorination and molten salt chlorination. Molten salt chlorination is currently the most effective and mature method for refining high calcium and magnesium materials, because molten salt has many superior properties, such as stability at high temperatures, low-temperature vapor pressure in a wide range, low viscosity, good conductivity, high heat capacity, reasonable ion migration and diffusion rate, and the ability to dissolve different mineral materials.

[0003] Molten salt chlorination production is to use sodium chloride as a medium to make titanium ore and chlorine react at high temperature, so that the oxides in the ore are converted into chlorides. In the production process, sodium chloride, petroleum coke and titanium-rich materials are mixed in a certain proportion and then fed into the chlorination furnace through the feeding system. Chlorine enters the molten salt at a certain flow rate, causing the molten salt to tumble and stir, providing good heat and mass transfer conditions for the chlorination reaction. The molten salt chlorination reaction process is a complex reaction of gas, liquid and solid three-phase mixing. During the reaction process, low-volatile liquid products and high-volatile gaseous products will be generated. The liquid products will dissolve in the molten salt to form new complexes, and the gaseous products will enter the bubbles. As the bubbles rise and reach the molten salt interface, the bubbles will burst, and the gaseous products will enter the dust collector through the chlorination furnace outlet for solid-liquid separation, and then separate TiCl4 from the furnace gas through direct and indirect condensation. The condensed TiCl4 is then separated by sedimentation to separate most of the high-boiling impurities, and the supernatant is removed by a combination of distillation and rectification to remove low-boiling impurities, ultimately obtaining the product TiCl4.

[0004] Although molten salt chlorination can digest materials that boiling chlorination cannot, it also has its own shortcomings. Compared with boiling chlorination, molten salt chlorination is more difficult to control and its production capacity is far lower than boiling chlorination. Therefore, a large-scale molten salt chlorination method for producing titanium tetrachloride is needed. Summary of the invention

[0005] The invention provides a method for producing titanium tetrachloride by large-scale molten salt chlorination.

[0006] The scheme of the present invention is:

[0007] A method for producing titanium tetrachloride by large-scale molten salt chlorination comprises the following steps:

[0008] 1) delivering a mixture of high titanium slag, sodium chloride and petroleum coke to a chlorination furnace through a spiral feeder, and controlling the feeding speed; controlling the molten salt detection components in the chlorination furnace to include TiO2, C, NaCl, Fe, CaCl2 and MgCl2, detecting the molten salt components in the chlorination furnace in real time, and adjusting the composition ratio of the mixture to ensure that the molten salt detection components are within the control range;

[0009] 2) Chlorine is fed into the bottom of the molten salt in the chlorination furnace through a chlorine spray gun, the chlorine intake speed is 38-42 m / s, and the rising speed of the chlorine in the molten salt is 0.4-0.5 m / s;

[0010] 3) The chlorination furnace is sprayed with leaching mud for temperature control. The spraying position is located at the top and middle of the chlorination furnace. The temperature in the middle of the chlorination furnace is maintained at 750±5°C, and the top temperature of the chlorination furnace is ≤500°C. The spraying amount is adjusted in real time according to the top and middle temperatures of the chlorination furnace by the DCS system. The pressure at the top of the chlorination furnace is maintained at -3 to 0.2 kPa. The top temperature of the chlorination furnace is lower than 500°C to avoid affecting the subsequent gas-solid separation and gas-liquid separation effects.

[0011] 4) The gas pipe of the chlorination furnace is connected to a gas-solid separation device at 14 to 16 m. After the gas comes out from the top outlet of the chlorination furnace, it passes through the gas-solid separation device to collect dust. The temperature of the dust collector is between 300 and 500 ° C. When the gas passes through the gas-solid separation device, solid particles are enriched on the pipe wall and then fall into the slag box. Most of the high-boiling impurities, such as ferric chloride, will be separated from the gas as the temperature decreases;

[0012] 5) In the direct condensation stage, the crude titanium tetrachloride slurry sprayed from the leaching device is sprayed on the dust-collected furnace gas, and the temperature of the furnace gas after dust collection is controlled to be ≤110°C. The condensed slurry is sent to the leaching circulation tank, and the leaching circulation tank sends the slurry to the chlorination furnace for spraying by a pump. The slurry in the leaching circulation tank is also pumped into the leaching device for circulation and spraying by a pump;

[0013] 6) In the indirect condensation stage, the furnace gas that has completed direct condensation is condensed by a condensation device. The temperature of the indirect condensation stage is ≤ 0°C. Then the condensed furnace gas is sent to the tail gas treatment through a drip collector;

[0014] 7) The liquid separated by the droplet catcher and the condensed liquid are sent to the condensation circulation tank for sedimentation in the sedimentation tank, and the supernatant crude titanium tetrachloride is sent to the refining and elution device in step 5) to obtain refined titanium tetrachloride; part of the mud separated by sedimentation is sent to the elution circulation tank.

[0015] As a preferred technical solution, in the step 1), the liquid level of the molten salt in the chlorination furnace is between 5m and 5.5m, and the liquid level of the molten salt in the chlorination furnace is less than the bottom of the feeding port of the chlorination furnace; in the molten salt detection control range, TiO2 is 1-2%; C is 3-5%; NaCl is 30-40%; Fe is 5%-9%; CaCl2<8%; MgCl2<25%, and the real-time detection of the molten salt composition in the chlorination furnace is to detect the molten salt composition every half an hour, and the ingredients are adjusted in real time according to the detection results, and the detection and ingredient adjustment time are completed within 1 hour.

[0016] As a preferred technical solution, in the step 1), the TiO2 content in the high-titanium slag in the mixed material grade is greater than 75%, and the particle size is 40-200 mesh; the water content in the mixed material is less than 0.3%; the SiO2 content in the mixed material is less than 5%; the CaO2+MgO2 in the mixed material is less than 5%; the MnO in the mixed material is less than 3%; and the Fe in the mixed material is less than 5%.

[0017] As a preferred technical solution, the gas-solid separation device in step 4) is a dust collector.

[0018] As a preferred technical solution, in step 3) and step 5), leaching mud is used for temperature control, and the leaching mud temperature is lower than 110°C; in step 3), the temperature of the chlorination furnace top is maintained between 400 and 500°C.

[0019] As a preferred technical solution, the sedimentation time of the sedimentation tank in step 7) is greater than 6 hours.

[0020] Due to the adoption of the above technical solution, a large-scale molten salt chlorination method for producing titanium tetrachloride is provided, 1) a mixture of high titanium slag, sodium chloride and petroleum coke is fed to a chlorination furnace through a spiral feeder, and the feeding speed is controlled; the molten salt detection components in the chlorination furnace are controlled to include TiO2, C, NaCl, Fe, CaCl2 and MgCl2, the molten salt components in the chlorination furnace are detected in real time, and the composition ratio of the mixture is adjusted to ensure that the molten salt detection components are within the control range; 2) the bottom of the molten salt in the chlorination furnace is cooled by chlorine gas Chlorine is fed into the spray gun, the intake speed of the chlorine is 38-42 m / s, and the rising speed of the chlorine in the molten salt is 0.4-0.5 m / s; 3) The chlorination furnace is sprayed with leaching mud for temperature control, and the spraying position is located at the top and middle of the chlorination furnace. The temperature in the middle of the chlorination furnace is maintained at 750±5°C, and the top temperature of the chlorination furnace is ≤500°C. The spraying amount adopts the DCS system, which is adjusted in real time according to the top and middle temperatures of the chlorination furnace, and the pressure on the top of the chlorination furnace is maintained at -3 to 0.2 kPa; 4) The gas pipe of the chlorination furnace is connected to the gas-solid separation device at 14 to 16 m, and the gas from the top outlet of the chlorination furnace is dusted by the gas-solid separation device, and the temperature of the dust collector is between 300 and 500 ° C; 5) The direct condensation stage is to spray the dust-collected gas with the crude titanium tetrachloride slurry sprayed by the leaching device, and the temperature of the gas after dust collection is controlled to be ≤110 ° C. The condensed slurry is sent to the leaching circulation tank, and the leaching circulation tank sends the slurry to the chlorination furnace for spraying by a pump. The mud is also pumped into the leaching device for circulating spraying; 6) the indirect condensation stage is to condense the furnace gas that has completed direct condensation through the condensing device, the temperature of the indirect condensation stage is ≤0°C, and then the condensed furnace gas is sent to the tail gas treatment through the droplet catcher; 7) the liquid separated by the droplet catcher and the condensed liquid are sent to the condensation circulation tank for sedimentation in the sedimentation tank, and the supernatant crude titanium tetrachloride is sent to the refining and leaching device in step 5) to obtain refined titanium tetrachloride; part of the mud separated by sedimentation is sent to the leaching circulation tank.

[0021] The invention has the advantages of increasing the molten salt chlorination capacity by expanding the chlorination furnace, improving the process control conditions, and reducing the control difficulty. A method for controlling production and increasing the chlorination rate of a large chlorination furnace is proposed to meet the production requirements of the subsequent products and avoid the shortcomings of molten salt chlorination.

[0022] Compared with the prior art, it has the following beneficial effects:

[0023] 1. The chlorination furnace is enlarged to improve the molten salt chlorination capacity. Through the improvement in the experiment, the diameter of the chlorination furnace is enlarged by 340mm, the height is enlarged by 180mm, and the capacity is increased to 75t / day;

[0024] 2. Improve the composition of molten salt and improve the chlorination efficiency of molten salt by finely controlling the composition of molten salt;

[0025] 3. Absorb high calcium magnesium titanium slag to further reduce the requirements for raw materials, improve raw material acceptance and reduce raw material costs;

[0026] 4. Fixed production temperature: the middle temperature of the chlorination furnace is 750±5℃, the top temperature is 450±10℃, the elution temperature is lower than 110℃, the condensation temperature is lower than 0℃, the production conditions are solidified, and the process control is simple; BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0028] In order to make up for the above shortcomings, the present invention provides a method for producing titanium tetrachloride by large-scale molten salt chlorination to solve the problems in the above background technology.

[0029] A method for producing titanium tetrachloride by large-scale molten salt chlorination comprises the following steps:

[0030] 1) delivering a mixture of high titanium slag, sodium chloride and petroleum coke to a chlorination furnace through a spiral feeder, and controlling the feeding speed; controlling the molten salt detection components in the chlorination furnace to include TiO2, C, NaCl, Fe, CaCl2 and MgCl2, detecting the molten salt components in the chlorination furnace in real time, and adjusting the composition ratio of the mixture to ensure that the molten salt detection components are within the control range;

[0031] 2) Chlorine is fed into the bottom of the molten salt in the chlorination furnace through a chlorine spray gun, the chlorine intake speed is 38-42 m / s, and the rising speed of the chlorine in the molten salt is 0.4-0.5 m / s;

[0032] 3) The chlorination furnace is sprayed with leaching mud for temperature control. The spraying position is located at the top and middle of the chlorination furnace. The temperature in the middle of the chlorination furnace is maintained at 750±5°C, and the top temperature of the chlorination furnace is ≤500°C. The spraying amount is adjusted in real time according to the top and middle temperatures of the chlorination furnace by the DCS system. The pressure at the top of the chlorination furnace is maintained at -3 to 0.2 kPa. The top temperature of the chlorination furnace is lower than 500°C to avoid affecting the subsequent gas-solid separation and gas-liquid separation effects.

[0033] 4) The gas pipe of the chlorination furnace is connected to a gas-solid separation device at 14 to 16 m. After the gas comes out from the top outlet of the chlorination furnace, it passes through the gas-solid separation device to collect dust. The temperature of the dust collector is between 300 and 500 ° C. When the gas passes through the gas-solid separation device, solid particles are enriched on the pipe wall and then fall into the slag box. Most of the high-boiling impurities, such as ferric chloride, will be separated from the gas as the temperature decreases;

[0034] 5) In the direct condensation stage, the crude titanium tetrachloride slurry sprayed from the leaching device is sprayed on the dust-collected furnace gas, and the temperature of the furnace gas after dust collection is controlled to be ≤110°C. The condensed slurry is sent to the leaching circulation tank, and the leaching circulation tank sends the slurry to the chlorination furnace for spraying by a pump. The slurry in the leaching circulation tank is also pumped into the leaching device for circulation and spraying by a pump;

[0035] 6) In the indirect condensation stage, the furnace gas that has completed direct condensation is condensed by a condensation device. The temperature of the indirect condensation stage is ≤ 0°C. Then the condensed furnace gas is sent to the tail gas treatment through a drip collector;

[0036] 7) The liquid separated by the droplet catcher and the condensed liquid are sent to the condensation circulation tank for sedimentation in the sedimentation tank, and the supernatant crude titanium tetrachloride is sent to the refining and elution device in step 5) to obtain refined titanium tetrachloride; part of the mud separated by sedimentation is sent to the elution circulation tank.

[0037] In the step 1), the liquid level of the molten salt in the chlorination furnace is between 5m and 5.5m, and the liquid level of the molten salt in the chlorination furnace is less than the bottom of the feeding port of the chlorination furnace; in the molten salt detection control range, TiO2 is 1-2%; C is 3-5%; NaCl is 30-40%; Fe is 5%-9%; CaCl2<8%; MgCl2<25%, and the real-time detection of the molten salt composition in the chlorination furnace is to detect the molten salt composition every half an hour, and the ingredients are adjusted in real time according to the detection results, and the detection and ingredient adjustment time are completed within 1 hour.

[0038] In the step 1), the TiO2 content in the high-titanium slag in the mixed material is greater than 75%, and the particle size is 40-200 mesh; the water content in the mixed material is less than 0.3%; the SiO2 content in the mixed material is less than 5%; the CaO2+MgO2 in the mixed material is less than 5%; the MnO in the mixed material is less than 3%; and the Fe in the mixed material is less than 5%.

[0039] The gas-solid separation device in step 4) is a dust collector.

[0040] In step 3) and step 5), the temperature of the leaching mud is controlled, and the temperature of the leaching mud is lower than 110°C; in step 3), the temperature of the top of the chlorination furnace is maintained between 400 and 500°C.

[0041] The sedimentation time of the sedimentation tank in step 7) is greater than 6 hours.

[0042] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further described below in conjunction with specific embodiments.

[0043] Example 1

[0044] 1) delivering a mixture of high titanium slag, sodium chloride and petroleum coke to a chlorination furnace through a spiral feeder, and controlling the feeding speed; controlling the molten salt detection components in the chlorination furnace to include TiO2, C, NaCl, Fe, CaCl2 and MgCl2, detecting the molten salt components in the chlorination furnace in real time, and adjusting the composition ratio of the mixture to ensure that the molten salt detection components are within the control range;

[0045] 2) Chlorine is fed into the bottom of the molten salt in the chlorination furnace through a chlorine spray gun, the chlorine intake speed is 38-42 m / s, and the rising speed of the chlorine in the molten salt is 0.4-0.5 m / s;

[0046] 3) The chlorination furnace is sprayed with leaching mud for temperature control. The spraying position is located at the top and middle of the chlorination furnace. The temperature in the middle of the chlorination furnace is maintained at 750±5°C, and the top temperature of the chlorination furnace is ≤500°C. The spraying amount is adjusted in real time according to the top and middle temperatures of the chlorination furnace by the DCS system. The pressure at the top of the chlorination furnace is maintained at -3 to 0.2 kPa. The top temperature of the chlorination furnace is lower than 500°C to avoid affecting the subsequent gas-solid separation and gas-liquid separation effects.

[0047] 4) The gas pipe of the chlorination furnace is connected to a gas-solid separation device at 14 to 16 m. After the gas comes out from the top outlet of the chlorination furnace, it passes through the gas-solid separation device to collect dust. The temperature of the dust collector is between 300 and 500 ° C. When the gas passes through the gas-solid separation device, solid particles are enriched on the pipe wall and then fall into the slag box. Most of the high-boiling impurities, such as ferric chloride, will be separated from the gas as the temperature decreases;

[0048] 5) In the direct condensation stage, the crude titanium tetrachloride slurry sprayed from the leaching device is sprayed on the dust-collected furnace gas, and the temperature of the furnace gas after dust collection is controlled to be ≤110°C. The condensed slurry is sent to the leaching circulation tank, and the leaching circulation tank sends the slurry to the chlorination furnace for spraying by a pump. The slurry in the leaching circulation tank is also pumped into the leaching device for circulation and spraying by a pump;

[0049] 6) In the indirect condensation stage, the furnace gas that has completed direct condensation is condensed by a condensation device. The temperature of the indirect condensation stage is ≤ 0°C. Then the condensed furnace gas is sent to the tail gas treatment through a drip collector;

[0050] 7) The liquid separated by the droplet catcher and the condensed liquid are sent to the condensation circulation tank for sedimentation in the sedimentation tank, and the supernatant crude titanium tetrachloride is sent to the refining and elution device in step 5) to obtain refined titanium tetrachloride; part of the mud separated by sedimentation is sent to the elution circulation tank.

[0051] In the step 1), the liquid level of the molten salt in the chlorination furnace is between 5m and 5.5m, and the liquid level of the molten salt in the chlorination furnace is less than the bottom of the feeding port of the chlorination furnace; in the molten salt detection control range, TiO2 is 1-2%; C is 3-5%; NaCl is 30-40%; Fe is 5%-9%; CaCl2<8%; MgCl2<25%, and the real-time detection of the molten salt composition in the chlorination furnace is to detect the molten salt composition every half an hour, and the ingredients are adjusted in real time according to the detection results, and the detection and ingredient adjustment time are completed within 1 hour.

[0052] In the step 1), the TiO2 content in the high-titanium slag in the mixed material is greater than 75%, and the particle size is 40-200 mesh; the water content in the mixed material is less than 0.3%; the SiO2 content in the mixed material is less than 5%; the CaO2+MgO2 in the mixed material is less than 5%; the MnO in the mixed material is less than 3%; and the Fe in the mixed material is less than 5%.

[0053] The gas-solid separation device in step 4) is a dust collector.

[0054] In step 3) and step 5), the temperature of the leaching mud is controlled, and the temperature of the leaching mud is lower than 110°C; in step 3), the temperature of the top of the chlorination furnace is maintained between 400 and 500°C.

[0055] The sedimentation time of the sedimentation tank in step 7) is greater than 6 hours.

[0056] 1. Mixture control:

[0057] The raw material control index can be greatly reduced, and the main mixed material index control is as follows:

[0058]

[0059] 2. Chlorination furnace

[0060] Size: Ф3640×15000; Capacity: 220~260t / d; The capacity of a large molten salt furnace can reach twice that of a small molten salt furnace. The internal structure of the chlorination furnace is elliptical and can be roughly divided into two sections, one is a cone section also called a reaction section, and the other is a straight section also called a solid-liquid separation section. The melt distribution is mainly between 5m and 5.5m, and the chlorine gas rising speed is between 0.4m / s-0.5m / s. The chlorination temperature is controlled between 730-760℃, and is stable at 750±5℃. The molten salt composition TiO2: 1-2%; C: 3-5%; NaCl: 30-40%; Fe: 5%-9%; CaCl2<8%; MgCl2<25% ensures that the molten salt composition is stable within the above range.

[0061] 3. Gas-solid separation device

[0062] A gravity dust collector with a double-cylinder cone bottom structure is used as a gas-solid separation device. The interception and condensation effects of the dust collector are used to separate solid particles and high-boiling impurities in the furnace gas, mainly separating unreacted high-titanium slag, petroleum coke and ferric chloride. The dust collector temperature needs to be controlled within 300-500℃, at which temperature ferric chloride can be collected to the maximum extent. Under normal production conditions, the furnace top temperature is controlled at 500℃, and the furnace gas temperature is about 450℃ after passing through the gravity dust collector.

[0063] 4. Direct condensation device

[0064] By directly spraying the crude titanium tetrachloride product and the eluted mud, the titanium tetrachloride furnace gas is condensed and most of the titanium tetrachloride is collected. At this time, the main components of titanium tetrachloride are titanium tetrachloride, aluminum chloride, ferric chloride, etc. The mud is returned to the chlorination furnace by a pump for cooling. Part of the ferric chloride and aluminum chloride can be used as reaction catalysts. The direct condensation temperature is controlled within 110°C.

[0065] 5. Indirect condensation

[0066] Through heat exchange between frozen brine and titanium tetrachloride, titanium tetrachloride in the furnace gas is further collected to improve the titanium yield. Indirect condensation adopts a two-stage method, with cooling water used for heat exchange in the first stage and frozen brine used for heat exchange in the second stage. The final outlet temperature is kept below 0°C. The titanium tetrachloride that has not been collected in the furnace gas will continue to be collected using a droplet catcher, mainly to collect the small droplets of titanium tetrachloride taken away from the furnace gas to achieve gas-liquid separation. After direct and indirect condensation, the titanium tetrachloride yield can basically reach more than 98%.

[0067] Embodiment 2:

[0068] The production conditions are solidified during production. The size of the chlorination furnace is Ф3640×15000, the temperature in the middle of the chlorination furnace is 750±5℃, and the temperature at the top of the furnace is 450±10℃. (1) The liquid level of the chlorination furnace is maintained between 5m-5.5m; the molten salt composition is controlled to be TiO2: 1-2%; C: 3-5%; NaCl: 30-40%; Fe: 5%-9%; CaCl2<8%; MgCl2<25%. The molten salt composition is detected in real time, and the raw material ratio is adjusted to ensure that the molten salt composition is stable within the above range. The chlorine gas inlet speed is 40m / s, the elution temperature is controlled within 110℃, and the condensation temperature is controlled below 0℃. The raw material used is a high-titanium slag with a TiO2 content of 75%, a titanium tetrachloride yield of 98%, and a production capacity of 215t / day.

[0069] Embodiment 3:

[0070] The production conditions are solidified during production. The size of the chlorination furnace is Ф3640×15000, the temperature in the middle of the chlorination furnace is 750±5℃, and the temperature at the top of the furnace is 450±10℃. (1) The liquid level of the chlorination furnace is maintained between 5m-5.5m; the molten salt composition is controlled to be TiO2: 1-2%; C: 3-5%; NaCl: 30-40%; Fe: 5%-9%; CaCl2<8%; MgCl2<25%. The molten salt composition is detected in real time, and the raw material ratio is adjusted to ensure that the molten salt composition is stable within the above range. The chlorine gas inlet speed is 40m / s, the elution temperature is controlled within 110℃, and the condensation temperature is controlled below 0℃. The raw material used is high-titanium slag with a TiO2 content of 85%, a titanium tetrachloride yield of 98%, and a production capacity of 235t / day.

[0071] Embodiment 4:

[0072] Solidification production conditions during production, chlorination furnace size Ф3640×15000, chlorination furnace middle temperature 750±5℃, furnace top temperature 450±10℃, (1) maintain chlorination furnace liquid level between 5m-5.5m; control molten salt composition at TiO2: 1-2%; C: 3-5%; NaCl: 30-40%; Fe: 5%-9%; CaCl2<8%; MgCl2<25%, real-time detection of molten salt composition, adjustment of raw material ratio to ensure that molten salt composition is stable within the above range. Chlorine gas inlet speed is 40m / s, elution temperature is controlled within 110℃, and condensation temperature is controlled below 0℃. The raw material uses high titanium slag with TiO2 content of 90%, titanium tetrachloride yield of 98%, and production capacity of 270t / day.

[0073] Under this control method, the influence of different chlorination furnaces on molten salt chlorination:

[0074] Example 5

[0075] Solidification production conditions during production, chlorination furnace size Ф3300×14020, chlorination furnace middle temperature 750±5℃, furnace top temperature 450±10℃, (1) maintain chlorination furnace liquid level between 5m-5.5m; control molten salt composition at TiO2: 1-2%; C: 3-5%; NaCl: 30-40%; Fe: 5%-9%; CaCl2<8%; MgCl2<25%, real-time detection of molten salt composition, adjustment of raw material ratio to ensure that molten salt composition is stable within the above range. Chlorine gas inlet speed is 40m / s, elution temperature is controlled within 110℃, and condensation temperature is controlled below 0℃. The raw material uses high titanium slag with a TiO2 content of 85%, a titanium tetrachloride yield of 98%, and a production capacity of 160t / day.

[0076] Study the effect of different control methods on molten salt chlorination under the same raw material conditions

[0077] Embodiment 6:

[0078] Solidification production conditions during production, chlorination furnace size Ф3640×15000, chlorination furnace middle temperature 750±5℃, furnace top temperature 400±10℃, (1) maintain chlorination furnace liquid level between 5m-5.5m; control molten salt composition at TiO2: 1-2%; C: 3-5%; NaCl: 30-40%; Fe: 5%-9%; CaCl2<8%; MgCl2<25%, real-time detection of molten salt composition, adjustment of raw material ratio to ensure that molten salt composition is stable within the above range. Chlorine gas inlet speed is 40m / s, elution temperature is controlled within 110℃, and condensation temperature is controlled below 0℃. The raw material uses high titanium slag with TiO2 content of 85%, titanium tetrachloride yield of 99%, and production capacity of 245t / day.

[0079] Embodiment 7:

[0080] During production, the solidification production conditions are as follows: the size of the chlorination furnace is Ф3640×15000, the temperature in the middle of the chlorination furnace is 750±5℃, the temperature at the top of the furnace is 500±10℃, (1) the liquid level of the chlorination furnace is maintained between 5m-5.5m; the composition of the molten salt is controlled to be TiO2: 1-2%; C: 3-5%; NaCl: 30-40%; Fe: 5%-9%; CaCl2<8%; MgCl2<25%, the composition of the molten salt is detected in real time, and the raw material ratio is adjusted to ensure that the composition of the molten salt is stable within the above range. The chlorine gas inlet speed is 40m / s, the elution temperature is controlled within 110℃, and the condensation temperature is controlled below 0℃. The raw material used is a high-titanium slag with a TiO2 content of 85%, a titanium tetrachloride yield of 96%, and a production capacity of 215t / day.

[0081] Embodiment 8:

[0082] Solidification production conditions during production, chlorination furnace size Ф3640×15000, chlorination furnace middle temperature 750±5℃, furnace top temperature 450±10℃, (1) maintain chlorination furnace liquid level between 5m-5.5m; control molten salt composition at TiO2: 1-2%; C: 3-5%; NaCl: 30-40%; Fe: 5%-9%; CaCl2<8%; MgCl2<25%, real-time detection of molten salt composition, adjustment of raw material ratio to ensure that molten salt composition is stable within the above range. Chlorine gas inlet speed is 35m / s, elution temperature is controlled within 110℃, and condensation temperature is controlled below 0℃. The raw material uses high titanium slag with TiO2 content of 85%, titanium tetrachloride yield of 98%, and production capacity of 200t / day.

[0083] Embodiment 9:

[0084] During production, the solidification production conditions are as follows: the size of the chlorination furnace is Ф3640×15000, the temperature in the middle of the chlorination furnace is 750±5℃, the temperature at the top of the furnace is 450±10℃, (1) the liquid level of the chlorination furnace is maintained between 5m-5.5m; the composition of the molten salt is controlled to be TiO2: 1-2%; C: 3-5%; NaCl: 30-40%; Fe: 5%-9%; CaCl2<8%; MgCl2<25%, the composition of the molten salt is detected in real time, and the raw material ratio is adjusted to ensure that the composition of the molten salt is stable within the above range. The chlorine gas inlet speed is 50m / s, the elution temperature is controlled within 110℃, and the condensation temperature is controlled below 0℃. The raw material used is a high-titanium slag with a TiO2 content of 85%, a titanium tetrachloride yield of 98%, and a production capacity of 215t / day.

[0085]

[0086] By comparing examples 2, 3, and 4, it is found that the grade of high-titanium slag has a greater influence on the chlorination of molten salt. However, under this control method, there is no obvious difference in low-grade high-titanium slag except for the low production capacity; comparing examples 3 and 5, the large-scale molten salt furnace has a positive effect on improving the production capacity of the chlorination furnace; comparing examples 3, 6, and 7, the lower the control temperature of the top of the molten salt chlorination furnace, the higher the yield, but it cannot be controlled too low, which will cause excessive slurry return; comparing examples 3, 8, and 9, both too low and too high chlorine feed rates are not conducive to the chlorination reaction. If it is too low, the stirring state of the molten salt is poor, and there is a risk of blocking the spray gun. If it is too high, the stirring is too violent and the chlorination reaction is insufficient.

[0087] In summary, the production conditions provided by the present invention are optimal process conditions for molten salt chlorination. The main influencing conditions for the molten salt chlorination yield are the control of furnace top temperature, elution temperature and condensation temperature. Too high or too low chlorine gas inlet speed is not conducive to the chlorination reaction. The optimal residence time of chlorine in molten salt is 4-5s.

[0088] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for producing titanium tetrachloride by large-scale molten salt chlorination, characterized in that: The following steps are involved: 1) A mixture of high-titanium slag, sodium chloride and petroleum coke is delivered to a chlorination furnace through a spiral feeder, and a feeding speed is controlled; the molten salt detection components in the chlorination furnace include TiO2, C, NaCl, Fe, CaCl2 and MgCl2, the molten salt components in the chlorination furnace are detected in real time, and the component ratio of the mixture is adjusted to ensure that the molten salt detection components are within a control range; the liquid level of the molten salt in the chlorination furnace is between 5m and 5.5m, and the liquid level of the molten salt in the chlorination furnace is less than the bottom of the feeding port of the chlorination furnace; in the molten salt detection control range, TiO2 is 1-2%; C is 3-5%; NaCl is 30-40%; Fe is 5%-9%; CaCl2<8%; MgCl2<25%, and the real-time detection of the molten salt components in the chlorination furnace is to detect the molten salt components every half an hour, and adjust the batching in real time according to the detection results, and the detection and batching adjustment time are completed within 1 hour; 2) Chlorine is fed into the bottom of the molten salt in the chlorination furnace through a chlorine spray gun, the chlorine intake speed is 38-42 m / s, and the rising speed of the chlorine in the molten salt is 0.4-0.5 m / s; 3) The chlorination furnace is sprayed with leaching mud for temperature control. The spraying position is located at the top and middle of the chlorination furnace. The temperature in the middle of the chlorination furnace is maintained at 750±5°C, and the temperature at the top of the chlorination furnace is 400-500°C. The spraying amount is adjusted in real time according to the top and middle temperatures of the chlorination furnace by the DCS system. The pressure at the top of the chlorination furnace is maintained at -3-0.2kPa; the temperature of the leaching mud is lower than 110°C; 4) The gas pipe of the chlorination furnace is connected to a gas-solid separation device at 14 to 16 m. After the gas comes out from the top outlet of the chlorination furnace, it passes through the gas-solid separation device to collect dust. The temperature of the dust collector is between 300 and 500 ° C. 5) In the direct condensation stage, the crude titanium tetrachloride slurry sprayed from the leaching device is sprayed on the dust-collected furnace gas, and the temperature of the furnace gas after dust collection is controlled to be ≤110°C. The condensed slurry is sent to the leaching circulation tank, and the leaching circulation tank sends the slurry to the chlorination furnace for spraying through a pump. The slurry in the leaching circulation tank is also pumped into the leaching device for cyclic spraying; the leaching slurry temperature is lower than 110°C; 6) In the indirect condensation stage, the furnace gas that has completed direct condensation is condensed by a condensation device. The temperature of the indirect condensation stage is ≤ 0°C. Then the condensed furnace gas is sent to the tail gas treatment through a drip collector; 7) The liquid separated by the droplet catcher and the condensed liquid are sent to the condensation circulation tank for sedimentation in the sedimentation tank, and the supernatant crude titanium tetrachloride is sent to the refining and elution device in step 5) to obtain refined titanium tetrachloride; part of the mud separated by sedimentation is sent to the elution circulation tank; the production capacity of the chlorination furnace is 220-260t / d.

2. A method for producing titanium tetrachloride by large-scale molten salt chlorination as claimed in claim 1, characterized in that: In the step 1), the TiO2 content in the high-titanium slag in the mixed material is greater than 75%, and the particle size is 40-200 mesh; the water content in the mixed material is less than 0.3%; the SiO2 content in the mixed material is less than 5%; the CaO2+MgO2 in the mixed material is less than 5%; the MnO in the mixed material is less than 3%; and the Fe in the mixed material is less than 5%.

3. A method for producing titanium tetrachloride by large-scale molten salt chlorination as claimed in claim 1, characterized in that: The gas-solid separation device in step 4) is a dust collector.

4. A method for producing titanium tetrachloride by large-scale molten salt chlorination as claimed in claim 1, characterized in that: The sedimentation time of the sedimentation tank in step 7) is greater than 6 hours.

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