A system and method for efficient boiling chlorination of titanium-rich materials

Abstract

A system and method for efficient boiling chlorination of titanium-rich materials. The system includes a chlorination furnace, a quencher, a U-shaped valve, a conical fluidized bed, a cyclone dust collector, a dust collection silo, a leaching and dust removal tower, a heat exchanger, a slurry storage tank, a circulation pump, and a slurry delivery pump. The method comprises: delivering titanium-rich material, petroleum coke, and chlorine to the chlorination furnace for chlorination; spraying a leaching slurry at the top of the chlorination furnace and the quencher to cool the high-temperature chlorinated flue gas; the flue gas is then sent to a cyclone dust collector and leaching and dust removal; and a conical fluidized bed is used for selective discharge of fine powder. Selective discharge of chlorinated residual fine powder prevents excessive accumulation that affects the efficiency of the chlorination furnace, while also reducing the dust content of the chlorinated flue gas and effectively avoiding blockage during the quenching process. Spraying a leaching slurry at the top of the furnace simultaneously achieves cooling of the chlorinated flue gas and treatment of the leaching slurry. Alkaline solution is sprayed into the leaching and dust removal tower to selectively hydrolyze aluminum chloride in the flue gas, avoiding blockage caused by saturated aluminum chloride precipitation during cooling and leaching.

Description

Technical Field

[0001] The present invention relates to the fields of chemical industry and metallurgy, and in particular to a system and method for efficient boiling chlorination of titanium-rich materials. Background Art

[0002] Fluidized chlorination involves the carbonization of titanium-containing materials in a fluidized bed to produce titanium tetrachloride as an intermediate. Titanium tetrachloride can be oxidized to produce titanium dioxide or reduced with magnesium to produce titanium sponge. Fluidized chlorination is a leading advanced titanium resource utilization technology with a short process, low cost, minimal pollution, and high production capacity. However, during the boiling chlorination process, fines are generated due to collisions between particles and between particles and the vessel wall. Furthermore, the chlorination reaction itself causes particle refinement and fines, resulting in a high concentration of fines in the flue gas from the boiling chlorination furnace. Furthermore, the chlorination flue gas also contains high-boiling-point chlorides such as ferric chloride and aluminum chloride. To prevent dust and high-boiling-point chlorides from condensing and entering the subsequent titanium tetrachloride product, titanium dioxide chloride manufacturers have implemented dust collection measures. Currently, the treatment of high-temperature titanium tetrachloride dust-laden gas, both domestically and internationally, primarily involves spraying crude titanium tetrachloride from the condensation and collection process and vanadium slag slurry from the refining process. This quenches the high-temperature titanium tetrachloride dust-laden gas to a temperature of 200-300°C before entering a dust collection chamber for gas-solid separation. Because the flue gas carries a large amount of dust, the spray slurry rapid cooling area is prone to clogging, requiring frequent stops for cleaning. Therefore, the dust removal process needs to be optimized.

[0003] CN108793237B discloses a system and method for treating high-temperature titanium tetrachloride dust-laden gas. This method eliminates the existing chilling and gas-solid separation steps and incorporates a wet chlorinated slag baking step, a condensation and pulping step, and a solid-liquid separation step. Specifically, the high-temperature chlorinated flue gas is fed into a rotary kiln, into which wet solids separated by a centrifuge are fed. The high-temperature chlorinated flue gas and wet solids are subjected to countercurrent contact and cooled to 400-600°C. The titanium tetrachloride in the wet chlorinated slag is evaporated into the dust-laden gas, and the wet chlorinated slag is heated and fed into a cooling kiln for cooling and subsequent treatment. Although this method eliminates the chilling and gas-solid separation steps, the wet chlorinated slag obtained by centrifugation has poor fluidity and can agglomerate in the rotary kiln. Furthermore, this process primarily cools the high-temperature chlorinated flue gas using the wet solids, rather than removing dust from the hot flue gas. The wet chlorinated slag is dried by the hot flue gas, and some fine powder is carried into the next step along with the cooled flue gas, adversely affecting the subsequent titanium tetrachloride condensation and tail gas treatment steps. CN101423246B discloses a liquid-phase dust collection method for titanium tetrachloride solid dust collection residue. This method returns 2-30% by weight of the washed titanium tetrachloride slurry to the temperature control and dust removal process, controls the temperature of the chlorinated flue gas, controls the dust removal of the solid dust collector, and simultaneously removes dust particles in the returned titanium tetrachloride. However, this method still does not solve the problem of frequent blockage of the injected slurry in the pipeline or cyclone separator inlet. CN101462766B discloses a cooling process for titanium tetrachloride furnace gas. The method involves sending high-temperature dust-laden chlorinated flue gas into a cyclone dust collector, returning the collected dust to the chlorination furnace for further chlorination, and then cooling the high-temperature gas after exiting the cyclone dust collector into a cooler equipped with a water-cooling jacket. The cooled chlorinated flue gas then enters a spray condensation tower for further cooling to 171-180°C, condensing gaseous chloride impurities such as AlCl3 and FeCl3. A bag filter is then used to remove chloride residue, and the relatively clean chlorinated flue gas enters subsequent processes for condensation. However, this method easily causes dust to accumulate in the chlorination furnace, affecting production efficiency. CN218516289U discloses a system for efficient gas-solid separation and recovery of fine coke powder from a boiling chlorination furnace. The system operates by passing the high-temperature flue gas from the chlorination furnace through an α-cyclone separator and a circulating cyclone separator to remove dust particles larger than 10 μm and 3 μm, respectively. The collected dust enters a pulping tank for subsequent recycling. This method collects dust from the chlorinated flue gas without cooling it, placing high demands on the separation equipment. Furthermore, unreacted components in the dust need to be subsequently recycled, resulting in a complex process and high costs.

[0004] Spraying crude titanium slurry into the top of the chlorination furnace can effectively reduce the temperature of the chlorinated flue gas, which is beneficial to the subsequent cooling and dust removal operations of the chlorinated flue gas. It can also realize the treatment of part of the leaching slurry. However, because the chlorination residue is mainly silicon dioxide that is difficult to chlorinate, excessive petroleum coke powder and calcium and magnesium chlorides, a large amount of chlorination residue dust entrained by the crude titanium slurry sprayed on the top is recycled into the chlorination furnace. Excessive accumulation of chlorination residue will significantly reduce the titanium oxide content in the chlorination furnace, and bottom slag discharge operation is required. However, because the boiling chlorination furnace is in a fully mixed flow state and the powder materials are evenly mixed, slag discharge at the bottom of the bed will cause a large amount of unreacted titanium raw materials to be discharged, and the subsequent separation and recovery process is complicated and the operating cost is high. Summary of the Invention

[0005] In view of the problems existing in the prior art, the present invention provides a system and method for efficient boiling chlorination of titanium-rich materials.

[0006] The technical solution of the present invention is:

[0007] A system for efficient boiling chlorination of titanium-rich materials, the system mainly comprising a chlorination furnace, a quencher, a conical fluidized bed, a U-shaped valve, a cyclone dust collector, a dust collecting bin, a leaching dust removal tower, a slurry storage tank, a slurry delivery pump (9), a circulation pump and a heat exchanger;

[0008] It includes a chlorination furnace, which is characterized by:

[0009] The feed port of the chlorination furnace is connected to the titanium-rich material and petroleum coke feed pipeline, the air inlet of the chlorination furnace is connected to the chlorine pipeline, the discharge port A of the chlorination furnace is connected to the feed port of the quencher, and the discharge port B of the chlorination furnace is connected to a conical fluidized bed; the discharge port of the quencher is connected to a cyclone dust collector; the air inlet of the conical fluidized bed is connected to a nitrogen pipeline, the feed port of the conical fluidized bed is connected to the crude titanium tetrachloride pipeline, the air outlet of the conical fluidized bed is connected to the inlet of the cyclone dust collector, and the discharge port of the conical fluidized bed is connected to the feed port of the U-shaped valve; the discharge port of the U-shaped valve is connected to the feed port of the chlorination furnace, and the air inlet of the U-shaped valve is connected to the nitrogen pipeline;

[0010] The discharge port of the cyclone dust collector is connected to the feed port of the dust collecting silo, and the air outlet of the cyclone dust collector is connected to the air inlet of the leaching dust removal tower; the air inlet of the leaching dust removal tower is connected to the alkali solution pipeline, the air outlet of the cyclone dust collector is connected to the pipeline of the flue gas leaching process, and the discharge port of the cyclone dust collector is connected to the feed port of the slurry storage tank; the first discharge port of the slurry storage tank is connected to the feed port of the slurry delivery pump, and the second discharge port of the slurry storage tank is connected to the feed port of the circulation pump; the feed port of the circulation pump is connected to the feed port of the heat exchanger; the discharge port of the heat exchanger is connected to the spray liquid feed port of the leaching dust removal tower; the discharge port of the slurry delivery pump is respectively connected to the liquid spray port at the top of the chlorination furnace and the liquid spray port at the top of the quencher.

[0011] A method for efficiently boiling chlorinating titanium-rich materials using the above system comprises the following steps:

[0012] The titanium-rich material and petroleum coke are sent to the chlorination furnace, and chlorine is introduced to react to form chlorinated flue gas containing titanium tetrachloride. The slurry sent by the slurry delivery pump is sprayed on the top of the chlorination furnace to pre-cool the chlorinated flue gas. The solid in the slurry enters the chlorination furnace, and the pre-cooled flue gas and the vaporized titanium tetrachloride in the slurry are sent to the quencher together. The chlorinated flue gas is further cooled by the slurry sent by the slurry delivery pump. The dust-containing chlorinated flue gas after cooling is sent to the cyclone dust collector for dust collection, and the collected dust is sent to the dust collection silo. The chlorinated flue gas after dust removal is sent to the leaching dust removal tower, and alkali solution is introduced for selective hydrolysis to convert aluminum chloride into aluminum oxide. Under the action of spraying slurry, the dust in the chlorinated flue gas is leached and the formed slurry is sent to the slurry storage tank. Part of the slurry is sent to the heat exchanger through a circulation pump, and after heat exchange, it enters the leaching dust removal tower. Part of the slurry is sent to the chlorination furnace, quencher and conical fluidized bed through a slurry delivery pump to cool the high-temperature chlorinated flue gas. The chlorinated flue gas after wet dust removal is sent to the leaching process through the top pipeline of the leaching dust removal tower to obtain titanium tetrachloride;

[0013] Under the action of fluidizing gas and titanium tetrachloride gas produced by chlorination, part of the solid in the chlorination furnace is discharged into the conical fluidized bed, nitrogen is introduced into the conical fluidized bed, and crude titanium tetrachloride liquid is sprayed in. The coarse powder is discharged from the bottom through a U-shaped valve and circulated back to the chlorination furnace, while the fine powder is carried out by the gas and sent to the cyclone dust collector.

[0014] Preferably, the titanium-rich material has a TiO2 content of 70% wt to 99% wt, an average particle size of 150 to 1500 μm, a CaO content of 0% wt to 1.0% wt, and a MgO content of 0% wt to 1.5% wt.

[0015] The petroleum coke has an average particle size of 500 to 2500 μm, a fixed carbon content of 95 to 100% wt, and a sulfur content of 0 to 3% wt.

[0016] Preferably, the temperature in the chlorination furnace is 900-1200° C., the pressure in the bed is 100-300 kPaA, the gas superficial velocity is 0.3-2.0 m / s, and the mass ratio of the titanium-rich material to the petroleum coke is 1:(0.25-0.3).

[0017] Preferably, the slurry is sprayed on the top of the chlorination furnace to reduce the temperature of the chlorinated flue gas to 400-700°C; the slurry is sprayed on the top of the quench cooler to reduce the temperature of the chlorinated flue gas to 200-400°C.

[0018] Preferably, the cone angle entering the conical fluidized bed is 15-45°, the bottom wind speed is 0.5-5.0 m / s, and the average residence time of the particles is 5-60 min.

[0019] Preferably, the flue gas outlet temperature of the leaching dust removal tower is 80-125°C, and the liquid-gas ratio of the circulating leaching process is 10-30 kg / m 3 , the empty tower gas velocity is 1.5~3.0m / s, and the gas residence time is 2~6s.

[0020] Preferably, the amount of alkali solution added is 100% wt to 300% wt of the theoretical amount of aluminum chloride hydrolysis.

[0021] Compared with the prior art, the present invention has the following outstanding advantages:

[0022] (1) The problem of frequent blockage of the quench pipe was effectively solved. By spraying the collected slurry in the slurry storage tank into the top of the chlorination furnace, the titanium tetrachloride in the slurry was recovered and the temperature of the chlorinated flue gas was significantly reduced. On this basis, a quench cooler was installed on the outlet pipe of the chlorination furnace to further reduce the temperature of the chlorinated flue gas. This effectively solved the problem of frequent blockage of the flue gas pipeline in the existing production process.

[0023] (2) Improved the chlorination efficiency of titanium-rich materials. Through the selective slag discharge of the conical bed, the fine powder of the chlorination residue is discharged to avoid excessive accumulation and improve the efficiency of the chlorination furnace. The use of a conical fluidized bed can change the gas velocity. Under the action of the injected titanium tetrachloride crude liquid, the powder entering the conical fluidized bed can undergo self-agglomeration and granulation, and then return to the chlorination furnace, while the powder that has not undergone self-agglomeration and granulation enters the cyclone separator for separation. The unreacted particles are recycled back to the chlorination furnace, effectively ensuring the residence time of the titanium raw material in the chlorination furnace, thereby improving the chlorination rate of the titanium-rich material and helping to improve the yield of titanium tetrachloride.

[0024] (3) By spraying alkaline solution into the leaching and dust removal tower, the aluminum chloride in the chlorinated flue gas is selectively hydrolyzed to solve the problem of aluminum chloride oversaturation, precipitation, scaling and blockage in subsequent processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] FIG1 is a schematic diagram of a system and method for efficient boiling chlorination of titanium-rich materials according to the present invention;

[0026] In the figure: 1-chlorination furnace, 2-quench cooler, 3-conical fluidized bed, 4-U-type valve, 5-cyclone dust collector, 6-dust collection silo, 7-leaching dust removal tower, 8-slurry storage tank, 9-slurry delivery pump, 10-circulation pump, 11-heat exchanger. DETAILED DESCRIPTION

[0027] Example 1

[0028] As shown in Figure 1, the system for efficient boiling chlorination of titanium-rich materials includes a chlorination furnace 1, on which titanium-rich materials and petroleum coke feed pipelines and chlorine pipelines are installed. The discharge port A and the discharge port B of the chlorination furnace 1 are respectively connected to a quencher 2 and a conical fluidized bed 3 through pipelines; a nitrogen pipeline and a crude titanium tetrachloride tube are installed on the conical fluidized bed 3, and the air outlet of the conical fluidized bed 3 is connected to a cyclone dust collector 5 through a pipeline. The discharge port of the conical fluidized bed 3 is connected to the chlorination furnace 1 through a pipeline, and a U-shaped valve is provided on the pipeline between the conical fluidized bed 3 and the chlorination furnace 1, and the air inlet of the U-shaped valve is connected to the nitrogen pipeline. ; The discharge port and air outlet of the cyclone dust collector 5 are respectively connected to the dust collecting bin 6 and the leaching dust removal tower 7; the air inlet and air outlet of the leaching dust removal tower 7 are respectively installed with an alkali solution pipeline and a flue gas leaching process pipeline, and the discharge port of the leaching dust removal tower 7 is connected to a slurry storage tank 8; the first discharge port and the second discharge port of the slurry storage tank 8 are respectively connected to a slurry delivery pump 9 and a circulating pump 10; the feed port of the circulating pump 10 is connected to a heat exchanger 11; the discharge port of the heat exchanger 11 is connected to the spray liquid feed port of the leaching dust removal tower 7; the discharge port of the slurry delivery pump 9 is respectively connected to the liquid spray port at the top of the chlorination furnace 1 and the liquid spray port at the top of the quencher 2.

[0029] The titanium-rich material pretreatment chlorination method comprises the following steps:

[0030] A titanium-rich material with a TiO2 content of 96.5%wt, a particle size range of 150-500μm, a CaO content of 0.23%wt, and a MgO content of 1.05%wt, and a petroleum coke with a particle size range of 350-1000μm, a fixed carbon content of 97.6%wt, and a sulfur content of 1.8%wt are sent to a chlorination furnace 1, with a mass ratio of the titanium-rich material to the petroleum coke being 1:0.25. Chlorine is introduced into the bottom of the fluidized bed, and the reaction is carried out at 900°C, a bed pressure of 100kPaA, and a gas superficial velocity of 1.0m / s. The liquid sprayed from the top of the chlorination furnace 1 rinses the slurry, reducing the temperature of the chlorinated flue gas to 400°C. The cooled chlorinated flue gas is introduced into a rapid cooling system. The quencher 2 is a quencher 2, and the leaching slurry is sprayed into the liquid spray port of the quencher 2 to further reduce the temperature of the chlorinated flue gas in the quencher 2 to 200°C; the dust-containing flue gas after cooling is sent to the cyclone dust collector 5, and the dust collected in the cyclone dust collector 5 is sent to the dust collecting bin 6 for dust removal; the chlorinated flue gas after dust removal is sent to the leaching dust removal tower 7, the air velocity of the tower is 1.5m / s, the gas residence time is 6s, and the 10% mass concentration of sodium hydroxide solution is sprayed into the air inlet of the leaching dust removal tower 7. The amount of sodium hydroxide solution added is 150% of the amount of aluminum chloride hydrolyzed (aluminum chloride in the flue gas is hydrolyzed). At the same time, the leaching slurry is sprayed into the spray port of the leaching dust removal tower 7, and the ratio of the leaching slurry to the chlorinated flue gas is 30kg / m 3, further leaching the dust in the chlorinated flue gas, and further reducing its temperature to 80 ° C. At the same time, the obtained leaching slurry is sent to the slurry storage tank 8. The chlorinated flue gas after wet dust removal is sent to the leaching process through the top pipeline of the leaching dust removal tower 7 to obtain titanium tetrachloride; a part of the slurry in the slurry storage tank 8 is sent to the heat exchanger 11 through the circulation pump 10 as the leaching slurry, and is cooled to 40 ° C in the heat exchanger 11, and then sent to the spray port at the top of the leaching dust removal tower 7; a part of the slurry in the slurry storage tank 8 is sent to the discharge port of the slurry delivery pump 9 as the leaching slurry The materials are transported to the top liquid spray outlets of chlorination furnace 1 and quencher 2, respectively. A portion of the solids in chlorination furnace 1 are discharged into a conical fluidized bed 3. The cone angle of the conical fluidized bed is 15°, and nitrogen is introduced into the bottom of the cone at a velocity of 0.5 m / s. The average residence time of the particles in the conical fluidized bed is 60 minutes. Crude titanium tetrachloride liquid (crude titanium liquid) and nitrogen are sprayed into the cone. The sorted coarse powder (material that meets the particle size requirements of the chlorination furnace raw material) is discharged through a U-valve 4 and circulated back to the chlorination furnace 1, while the fine powder is carried away by the gas and sent to a cyclone dust collector 5. Under these operating conditions, the aluminum chloride content in the leaching slurry is 0.01%wt, and the titanium chlorination rate in the system is 98.3%.

[0031] Example 2

[0032] The system for efficient boiling chlorination of titanium-rich materials of Example 1 is used. Titanium-rich materials with a TiO2 content of 70% wt, a particle size range of 1000-1500 μm, a CaO content of 1.0% wt, and a MgO content of 1.5% wt, and petroleum coke with a particle size range of 1500-2500 μm, a fixed carbon content of 95% wt, and a sulfur content of 3% wt are fed to a chlorination furnace 1. The mass ratio of the titanium-rich material to the petroleum coke is 1:0.3. Chlorine is introduced into the bottom of the fluidized bed and reacted at 1200° C., a bed pressure of 300 kPaA, and a gas superficial velocity of 2.0 m / s. The slurry is washed by a liquid spray port at the top of the chlorination furnace 1 to reduce the chlorinated flue gas to 700° C. After cooling, the chlorinated flue gas is cooled to 400° C. The chlorinated flue gas is passed into the quencher 2, and the leaching slurry is sprayed into the liquid spray port of the quencher 2 to further reduce the temperature of the chlorinated flue gas in the quencher 2 to 400°C; the dust-laden flue gas after cooling is sent to the cyclone dust collector 5, and the dust collected in the cyclone dust collector 5 is sent to the dust collecting bin 6; the chlorinated flue gas after dust removal is sent to the leaching dust removal tower 7, the air velocity of the tower is 3m / s, the gas residence time is 2s, and the sodium hydroxide solution with a mass concentration of 10% is sprayed into the air inlet of the leaching dust removal tower 7, and the amount added is 300% of the amount of aluminum chloride hydrolyzed (aluminum chloride in the flue gas is hydrolyzed). At the same time, the leaching slurry is sprayed into the spray port of the leaching dust removal tower 7, and the ratio of the leaching slurry to the chlorinated flue gas is 10kg / m 3, further leaching the dust in the chlorinated flue gas, and further reducing its temperature to 125 ° C. At the same time, the obtained leached slurry is sent to the slurry storage tank 8. The chlorinated flue gas after wet dust removal is sent to the leaching process through the top pipeline of the leaching dust removal tower 7 to obtain titanium tetrachloride; a part of the slurry in the slurry storage tank 8 is sent to the heat exchanger 11 through the circulation pump 10 as the leaching slurry, and is cooled to 60 ° C in the heat exchanger 11, and then sent to the spray port at the top of the leaching dust removal tower 7; a part of the slurry in the slurry storage tank 8 is sent to the slurry storage tank 8 through the slurry storage tank 8. The discharge port of delivery pump 9 is used as leaching slurry and is transported to the top liquid spray port of chlorination furnace 1 and the top liquid spray port of quencher 2 respectively. Some solids in chlorination furnace 1 are discharged into conical fluidized bed 3. The cone angle of the conical fluidized bed is 30 degrees. Nitrogen is introduced into the bottom of the cone at a wind speed of 5.0m / s. The average residence time of particles in the conical fluidized bed is 5 minutes. Crude titanium tetrachloride liquid and nitrogen are sprayed into the cone. The coarse powder that is sorted is discharged and circulated back to chlorination furnace 1 through U-valve 4, while the fine powder is carried out by the gas and sent to cyclone dust collector 5. Under these operating conditions, the aluminum chloride content in the leaching slurry is 0.001%wt, and the titanium chlorination rate of the system is 98.6%.

[0033] Example 3

[0034] The system for efficient boiling chlorination of titanium-rich material of Example 1 is adopted, and titanium-rich material with TiO2 content of 99%wt, particle size range of 150-500μm, CaO content of 0%wt, MgO content of 0%wt, and petroleum coke with particle size range of 500-1000μm, fixed carbon content of 100%wt, and sulfur content of 0%wt is delivered to chlorination furnace 1, and the mass ratio of titanium-rich material to petroleum coke is 1:0.25. Chlorine is introduced into the bottom of the fluidized bed, and the reaction is carried out at 1100°C, a bed pressure of 200kPaA, and a gas superficial velocity of 0.3m / s; the liquid spray port sprayed into the top of the chlorination furnace 1 washes the slurry, and the chlorinated flue gas is reduced to 480°C. After cooling, the chlorinated flue gas is cooled to 480°C. The chlorinated flue gas is passed into the quencher 2, and the leaching slurry is sprayed into the liquid spray port of the quencher 2 to further reduce the temperature of the chlorinated flue gas in the quencher 2 to 350°C; the dust-laden flue gas after cooling is sent to the cyclone dust collector 5, and the dust collected in the cyclone dust collector 5 is sent to the dust collecting bin 6; the chlorinated flue gas after dust removal is sent to the leaching dust removal tower 7, the superficial gas velocity is 2.0m / s, the gas residence time is 4s, and a sodium hydroxide solution with a mass concentration of 10% is sprayed into the air inlet of the leaching dust removal tower 7, the amount of which is 100% of the amount of aluminum chloride hydrolyzed (aluminum chloride in the hydrolyzed flue gas), and the leaching slurry is sprayed into the leaching dust removal tower 7 at the same time, and the ratio of the leaching slurry to the chlorinated flue gas is 20kg / m 3, further leaching the dust in the chlorinated flue gas, and further reducing its temperature to 120 ° C. At the same time, the obtained leached slurry is sent to the slurry storage tank 8. The chlorinated flue gas after wet dust removal is sent to the leaching process through the top pipeline of the leaching dust removal tower 7 to obtain titanium tetrachloride; part of the slurry in the slurry storage tank 8 is sent to the heat exchanger 11 through the circulation pump 10, and is cooled to 60 ° C in the heat exchanger 11, and then sent to the spray port at the top of the leaching dust removal tower 7; part of the slurry in the slurry storage tank 8 is discharged through the discharge port of the slurry delivery pump 9 The leaching slurry is transported to the top liquid spray outlet of chlorination furnace 1 and the top liquid spray outlet of quencher 2 respectively. Part of the solids in chlorination furnace 1 are discharged into conical fluidized bed 3. The cone angle of the conical fluidized bed is 20 degrees. Nitrogen is introduced into the bottom of the cone at a wind speed of 3.0m / s. The average residence time of the particles in the conical fluidized bed is 30 minutes. Crude titanium tetrachloride liquid is sprayed into the cone, and the crude titanium tetrachloride is converted into gas and nitrogen. The coarse powder is discharged from the bottom through U-valve 4 and circulated back to chlorination furnace 1, while the fine powder is carried out by the gas and sent to cyclone dust collector 5. Under these operating conditions, the aluminum chloride content in the leaching slurry is 0.05%wt, and the titanium chlorination rate of the system is 98.1%.

[0035] Example 4

[0036] The system for efficient boiling chlorination of titanium-rich material of Example 1 is adopted, and titanium-rich material with a TiO2 content of 92.1%wt, a particle size range of 150-500 μm, a CaO content of 0.12%wt, and a MgO content of 0.95%wt, and petroleum coke with a particle size range of 500-1000 μm, a fixed carbon content of 98.1%wt, and a sulfur content of 1.2%wt is delivered to a chlorination furnace 1, and the mass ratio of titanium-rich material to petroleum coke is 1:0.28. Chlorine is introduced into the bottom of the fluidized bed and reacted at 1000°C, a bed pressure of 150 kPaA, and a gas superficial velocity of 2.0 m / s; the liquid spray port sprayed into the top of the chlorination furnace 1 washes the slurry, and the chlorinated flue gas is reduced to 500°C. After The cooled chlorinated flue gas is passed into the quencher 2, and the leaching slurry is sprayed into the liquid spray port of the quencher 2 to further reduce the temperature of the chlorinated flue gas in the quencher 2 to 400°C; the dust-laden flue gas after cooling is sent to the cyclone dust collector 5, and the dust collected in the cyclone dust collector 5 is sent to the dust collecting bin 6; the chlorinated flue gas after dust removal is sent to the leaching dust removal tower 7, the air velocity of the tower is 2.5m / s, the gas residence time is 3s, and a sodium hydroxide solution with a mass concentration of 10% is sprayed into the air inlet of the leaching dust removal tower 7, the amount of which is 150% of the amount of aluminum chloride hydrolyzed (aluminum chloride in the flue gas is hydrolyzed), and the leaching slurry is sprayed into the spray port of the leaching dust removal tower 7 at the same time. The ratio of the leaching slurry to the chlorinated flue gas is 15kg / m 3, further leaching the dust in the chlorinated flue gas, and further reducing its temperature to 100 ° C. At the same time, the obtained leached slurry is sent to the slurry storage tank 8. The chlorinated flue gas after wet dust removal is sent to the leaching process through the top pipeline of the leaching dust removal tower 7 to obtain titanium tetrachloride; a part of the slurry in the slurry storage tank 8 is sent to the heat exchanger 11 through the circulation pump 10 as the leaching slurry, and is cooled to 50 ° C in the heat exchanger 11, and then sent to the spray port on the top of the leaching dust removal tower 7; a part of the slurry in the slurry storage tank 8 is sent to the slurry delivery port 11 through the slurry delivery port 11 as the leaching slurry The discharge port of pump 9 is used as the leaching slurry and is transported to the top liquid spray port of chlorination furnace 1 and the top liquid spray port of quencher 2 respectively. Part of the solids in chlorination furnace 1 are discharged into conical fluidized bed 3. The cone angle of the conical fluidized bed is 20 degrees. Nitrogen is introduced into the bottom of the cone at a wind speed of 1.5m / s. The average residence time of the particles in the conical fluidized bed is 45 minutes. Crude titanium tetrachloride liquid and nitrogen are sprayed into the cone. The coarse powder that is sorted is discharged and circulated back to chlorination furnace 1 through U-valve 4, while the fine powder is carried out by the gas and sent to cyclone dust collector 5. Under these operating conditions, the aluminum chloride content in the leaching slurry is 0.01%wt, and the titanium chlorination rate of the system is 98.4%.

[0037] Example 5

[0038] The system of efficient boiling chlorination of titanium-rich material of Example 1 is adopted, and titanium-rich material with TiO2 content of 90.8%wt, particle size range of 500-1000μm, CaO content of 0.22%wt, MgO content of 1.12%wt, and petroleum coke with particle size range of 500-1000μm, carbon content of 97.6%wt, sulfur content of 1.8%wt is delivered to chlorination furnace 1, and the mass ratio of titanium-rich material to petroleum coke is 1:0.3. Chlorine is introduced into the bottom of the fluidized bed, and the reaction is carried out at 950°C, bed pressure of 280kPaA, and gas superficial velocity of 2.5m / s; the liquid spray port sprayed into the top of the chlorination furnace 1 washes the slurry, and the chlorinated flue gas is reduced to 420°C. After cooling The cooled chlorinated flue gas is passed into the quencher 2, and the leaching slurry is sprayed into the liquid spray port of the quencher 2 to further reduce the temperature of the chlorinated flue gas in the quencher 2 to 280°C; the dust-laden flue gas after cooling is sent to the cyclone dust collector 5, and the dust collected in the cyclone dust collector 5 is sent to the dust collecting bin 6; the chlorinated flue gas after dust removal is sent to the leaching dust removal tower 7, the air velocity of the tower is 1.8m / s, the gas residence time is 3s, and a sodium hydroxide solution with a mass concentration of 10% is sprayed into the air inlet of the leaching dust removal tower 7. The amount of sodium hydroxide solution added is 200% of the amount of aluminum chloride hydrolyzed (aluminum chloride in the flue gas is hydrolyzed). At the same time, the leaching slurry is sprayed into the spray port of the leaching dust removal tower 7, and the ratio of the leaching slurry to the chlorinated flue gas is 24kg / m 3, further leaching the dust in the chlorinated flue gas, and further reducing its temperature to 85 ° C. At the same time, the obtained leached slurry is sent to the slurry storage tank 8. The chlorinated flue gas after wet dust removal is sent to the leaching process through the top pipeline of the leaching dust removal tower 7 to obtain titanium tetrachloride; a part of the slurry in the slurry storage tank 8 is sent to the heat exchanger 11 through the circulation pump 10 as the leaching slurry, and is cooled to 40 ° C in the heat exchanger 11, and then sent to the spray port on the top of the leaching dust removal tower 7; a part of the slurry in the slurry storage tank 8 is sent to the slurry delivery port 11 through the slurry delivery port 11 as the leaching slurry The discharge port of pump 9 is used as a leaching slurry and is transported to the top liquid spray port of chlorination furnace 1 and the top liquid spray port of quencher 2 respectively. Some solids in chlorination furnace 1 are discharged into conical fluidized bed 3. The cone angle of the conical fluidized bed is 15 degrees, and nitrogen is introduced into the bottom of the cone at a wind speed of 3.5m / s. The average residence time of particles in the conical fluidized bed is 25 minutes. Crude titanium tetrachloride liquid and nitrogen are sprayed into the cone. The coarse powder that is sorted is discharged and circulated back to chlorination furnace 1 through U-valve 4, while the fine powder is carried out by the gas and sent to cyclone dust collector 5. Under these operating conditions, the aluminum chloride content in the leaching slurry is 0.005%wt, and the titanium chlorination rate of the system is 99.1%.

[0039] Comparative Example 1

[0040] In this comparative example, no alkali solution is sprayed into the air inlet of the leaching and dust removal tower 7, and the rest is the same as in Example 5. Since aluminum chloride is selectively hydrolyzed, aluminum chloride precipitates and adheres to the heat exchanger tube wall due to leaching cooling in the subsequent leaching process, blocking the heat exchange tube and causing frequent shutdown and cleaning of the heat exchanger.

[0041] In summary, the present invention forcibly discharges nearly completely converted fine powder by sorting, while returning under-reacted coarse powder to continue reaction, enabling the selective discharge of residual gangue fine powder, preventing excessive accumulation and improving the efficiency of the chlorination furnace. Furthermore, spraying titanium tetrachloride on the top of the chlorination furnace lowers the flue gas temperature and recovers titanium tetrachloride from the slurry, thereby helping to increase titanium tetrachloride yield. By injecting alkaline solution into the leaching and dust removal tower to hydrolyze aluminum chloride in the flue gas, the problem of aluminum chloride oversaturation, precipitation, scaling, and blockage in subsequent processes is resolved.

[0042] The above embodiments are intended to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions to the technical solutions of the present invention do not depart from the spirit and scope of the technical solutions of the present invention and should be encompassed within the scope of the claims of the present invention.

Claims

1. A high-efficiency boiling chlorination system for titanium-rich materials, comprising a chlorination furnace (1), characterized in that: The feed port of the chlorination furnace (1) is connected to the titanium-rich material and petroleum coke feed pipeline, the air inlet of the chlorination furnace (1) is connected to the chlorine pipeline, the discharge port A of the chlorination furnace (1) is connected to the feed port of the quencher (2), and the discharge port B of the chlorination furnace (1) is connected to a conical fluidized bed (3); the discharge port of the quencher (2) is connected to a cyclone dust collector (5); the air inlet of the conical fluidized bed (3) is connected to a nitrogen pipeline, the feed port of the conical fluidized bed (3) is connected to a crude titanium tetrachloride pipeline, the air outlet of the conical fluidized bed (3) is connected to an inlet of the cyclone dust collector (5), and the discharge port of the conical fluidized bed (3) is connected to the feed port of the U-shaped valve (4); the discharge port of the U-shaped valve (4) is connected to the feed port of the chlorination furnace (1), and the air inlet of the U-shaped valve (4) is connected to the nitrogen pipeline; The discharge port of the cyclone dust collector (5) is connected to the feed port of the dust collecting bin (6), and the air outlet of the cyclone dust collector (5) is connected to the air inlet of the leaching dust removal tower (7); the air inlet of the leaching dust removal tower (7) is connected to the alkali solution pipeline, the air outlet of the cyclone dust collector (5) is connected to the pipeline of the flue gas leaching process, and the discharge port of the cyclone dust collector (5) is connected to the feed port of the slurry storage tank (8); the first discharge port of the slurry storage tank (8) The slurry delivery pump (9) is connected to the feed port, and the second discharge port of the slurry storage tank (8) is connected to the feed port of the circulation pump (10); the feed port of the circulation pump (10) is connected to the feed port of the heat exchanger (11); the discharge port of the heat exchanger (11) is connected to the spray liquid feed port of the leaching and dust removal tower (7); and the discharge port of the slurry delivery pump (9) is respectively connected to the top liquid spray port of the chlorination furnace (1) and the top liquid spray port of the quencher (2).

2. A method for efficiently boiling chlorinating titanium-rich materials using the system of claim 1, characterized in that: The following steps are involved: The titanium-rich material and petroleum coke are sent to the chlorination furnace (1), and chlorine is introduced to react to form chlorinated flue gas containing titanium tetrachloride. The slurry sent by the slurry delivery pump (9) is sprayed on the top of the chlorination furnace (1) to pre-cool the chlorinated flue gas. The solid in the slurry enters the chlorination furnace (1), and the pre-cooled flue gas and the vaporized titanium tetrachloride in the slurry are sent to the quencher (2). The chlorinated flue gas is further cooled by the slurry sent by the slurry delivery pump (9). The dust-containing chlorinated flue gas after cooling is sent to the cyclone dust collector (5) for dust collection, and the dust collected is sent to the dust collection bin (6). The chlorinated flue gas is sent to the leaching dust removal tower (7), and alkali solution is introduced for selective hydrolysis to convert aluminum chloride in the chlorinated flue gas into aluminum oxide. Under the action of the spray slurry, the dust in the chlorinated flue gas is leached, and the formed slurry is sent to the slurry storage tank (8). Part of the slurry is sent to the heat exchanger (11) through the circulation pump (10), and then enters the leaching dust removal tower (7) after heat exchange. Part of the slurry is sent to the chlorination furnace (1), the quencher (2) and the conical fluidized bed (3) through the slurry delivery pump (9) to cool the high-temperature chlorinated flue gas. The chlorinated flue gas after wet dust removal is sent to the leaching process through the top pipeline of the leaching dust removal tower (7) to obtain titanium tetrachloride; Under the action of fluidizing gas and titanium tetrachloride gas generated by chlorination, part of the solid in the chlorination furnace (1) is discharged into the conical fluidized bed (3). Nitrogen is introduced into the conical fluidized bed (3), and crude titanium tetrachloride liquid is sprayed into the conical fluidized bed (3). The coarse powder is discharged from the bottom through the U-shaped valve (4) and circulated back to the chlorination furnace (1), while the fine powder is carried out by the gas and sent to the cyclone dust collector (5).

3. The method for efficient boiling chlorination of titanium-rich material according to claim 2, characterized in that: The titanium-rich material has a TiO2 content of 70%wt to 99%wt, an average particle size of 150 to 1500 μm, a CaO content of 0%wt to 1.0%wt, and a MgO content of 0%wt to 1.5%wt.

4. The method for efficient boiling chlorination of titanium-rich material according to claim 2, characterized in that: The petroleum coke has an average particle size of 500 to 2500 μm, a fixed carbon content of 95 to 100% wt, and a sulfur content of 0 to 3% wt.

5. The method for efficient boiling chlorination of titanium-rich material according to claim 2, characterized in that: The temperature in the chlorination furnace (1) is 900-1200°C, the pressure in the bed is 100-300 kPaA, and the gas superficial velocity is 0.3-2.0 m / s.

6. The method for efficient boiling chlorination of titanium-rich materials according to claim 2, characterized in that: The mass ratio of titanium-rich material to petroleum coke is 1: (0.25~0.3).

7. The method for efficient boiling chlorination of titanium-rich materials according to claim 2, characterized in that: The chlorination furnace (1) sprays a slurry on the top to reduce the temperature of the chlorinated flue gas to 400-700°C; the quencher (2) sprays a slurry on the top to reduce the temperature of the chlorinated flue gas to 200-400°C.

8. The method for efficient boiling chlorination of titanium-rich materials according to claim 2, characterized in that: The conical fluidized bed (3) has a conical angle of 15 to 45 degrees, a bottom wind speed of 0.5 to 5.0 m / s, and an average particle residence time of 5 to 60 minutes.

9. The method for efficient boiling chlorination of titanium-rich materials according to claim 2, characterized in that: The flue gas outlet temperature of the leaching dust removal tower (7) is 80-125°C, and the liquid-gas ratio of the circulating leaching process is 10-30 kg / m 3 , the empty tower gas velocity is 1.5~3.0m / s, and the gas residence time is 2~6s.

10. The method for efficient boiling chlorination of titanium-rich materials according to claim 9, characterized in that: The amount of alkali solution added is 100%wt to 300%wt of the theoretical amount of aluminum chloride hydrolyzed in the flue gas.

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