Vanadium ore roasting shaft kiln and roasting method

Abstract

The present application belongs to the technical field of vanadium ore smelting, and particularly relates to a vanadium ore roasting shaft kiln and a roasting method. The vanadium ore roasting shaft kiln comprises a vertical kiln body and a temperature control device for monitoring the temperature of a roasting chamber in the kiln body. The kiln body comprises multiple groups of kilns which are in communication with each other. Each group of kilns is provided with a flue gas passage at the top, and an induced draft fan is installed on the flue gas passage. The bottom of the kiln body is provided with a cooling chamber, and a discharge chain plate is installed on the cooling chamber. A furnace door which is in communication with a feeding passage is arranged on the wall near the top of the kiln body. The input end of the feeding passage is connected to a distributing machine. The interior of the kiln body between the furnace door and the cooling chamber is a roasting chamber. The outer side of the kiln body around the roasting chamber is wrapped with a heat preservation device. An air preheating cavity is arranged on the inner side of the heat preservation device and the outer side of the kiln body. The air preheating cavity is in communication with the roasting chamber through fire bricks. The present application realizes the combustion of internal and external heating sources in multiple groups of kilns through the shaft kiln, thereby saving a large amount of energy and achieving the standard emission of waste gas.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of vanadium ore smelting, and particularly relates to a vanadium ore roasting shaft kiln and a roasting method. BACKGROUND

[0002] Vanadium is an important strategic resource. Vanadium can be added to metals such as steel as a micro-alloying element to improve the strength, hardness and wear resistance of the steel. In the extraction process of vanadium, vanadium ore powder is usually granulated and high-temperature oxidized to destroy the mineral structure of the vanadium ore powder, so that V(IV) and V(V) in the vanadium ore are combined with potassium salt, sodium salt and calcium salt in the mineral to form vanadate and metavanadate that are soluble in sulfuric acid.

[0003] Because the primary vanadium ore contains a large amount of coal and part of organic matter, it has a certain heat value. Therefore, the traditional vanadium extraction process adopts a coal gasification-shaft kiln briquetting roasting process, that is, coal is added in the high-temperature roasting process to realize the roasting of vanadium ore briquettes and to produce coal gas by using the coal. However, this process has the following problems. On the one hand, coal is used as raw material, and the coal consumption is large. On the other hand, because the shaft kiln has a deep hearth and poor air permeability, and the vanadium ore briquettes have a large diameter and high density, air is difficult to penetrate into the shaft kiln, which not only easily causes half-burned material or sintering of the kiln, but also affects the roasting efficiency and conversion rate of the vanadium ore. SUMMARY

[0004] The present application aims to overcome the defects of the prior art and provide a vanadium ore roasting shaft kiln and a roasting method.

[0005] The present application provides a vanadium ore roasting shaft kiln,

[0006] which comprises a vertical kiln body and a temperature control device for monitoring the temperature of a roasting chamber in the kiln body.

[0007] The kiln body comprises a plurality of groups of kiln furnaces that are connected to each other,

[0008] each group of kiln furnaces is provided with a flue gas passage at the top, and an induced draft fan is installed on the flue gas passage, and the bottom of the kiln furnace is provided with a cooling chamber, and a discharge chain plate is installed in the cooling chamber, and a furnace door that is connected to a feeding passage is arranged on the wall near the top of the kiln body, and the input end of the feeding passage is connected to a distributing machine, and the interior of the kiln furnace between the furnace door and the cooling chamber is a roasting chamber.

[0009] The kiln body outside the roasting chamber is wrapped with a heat preservation device, and an air preheating cavity is arranged between the inner side of the heat preservation device and the outer side of the kiln body, and the air preheating cavity is connected to the roasting chamber through fire bricks.

[0010] The temperature control device is arranged in the roasting chamber and the air preheating cavity,

[0011] The air preheating cavity is further connected with the gas output end of the gas generator through a gas pipeline;

[0012] The roasting chamber comprises a lower roasting chamber and an upper pre-roasting chamber arranged from bottom to top, and the lower roasting chamber is separated from the upper pre-roasting chamber by an upper furnace bridge, and the lower roasting chamber is separated from the cooling chamber by a lower furnace bridge;

[0013] Further, the fire-through bricks are red bricks or / and refractory bricks, and a plurality of air holes are arranged on the fire-through bricks for allowing the preheated gas to enter the roasting chamber, and the air holes are arranged at the upper part of the lower roasting chamber and the lower part of the upper pre-roasting chamber;

[0014] Further, a burner is arranged on the outer wall of the air preheating cavity, the gas pipeline is sleeved on the burner, and the air preheating cavity is connected with the gas output end of the gas generator through the gas pipeline on the burner;

[0015] Further, the kiln body comprises two groups of kiln bodies which are communicated through the fire-through bricks, and each group of kiln bodies is single-layer refractory brick and concrete masonry, and the outer side of the two groups of kiln bodies is wrapped with the heat preservation device, the heat preservation device comprises a metal shell and heat preservation cotton, and the heat preservation cotton is arranged between the inner side of the metal shell and the outer side of the air preheating cavity;

[0016] Further, the air preheating cavities are arranged between adjacent kilns;

[0017] Further, the temperature control device is a thermocouple,

[0018] The method for roasting vanadium ore by using the vanadium ore roasting shaft kiln comprises at least the following steps:

[0019] Step 1, sending the vanadium ore particles into the roasting chamber of the shaft kiln;

[0020] Step 2, starting the gas generator, sending the gas into the air preheating cavity, preheating the gas in the air preheating cavity to form preheated gas, and preheating the air or oxygen by the heat emitted by the gas to form preheated air, and then the preheated gas and the preheated air enter the roasting chamber through the air holes on the fire-through bricks;

[0021] Step 3, starting the induced draft fan, discharging the flue gas in the kiln body to the flue gas treatment system through the flue gas passage, and maintaining the temperature of the roasting chamber in the kiln body at 300-800℃ to roast the vanadium ore particles;

[0022] During the roasting process, the temperature in the kiln is monitored by the temperature control device, and the wind speed and wind pressure of the induced draft fan and the temperature of the gas generated by the gas generator entering the air preheating cavity are adjusted by the temperature control device to control the roasting temperature;

[0023] Step 4, after the roasting is completed, the discharge chain plate is opened to transport the vanadium ore particles in the cooling chamber out of the kiln body.

[0024] Furthermore, the particle size of the vanadium ore particles is 30-40 mm.

[0025] Furthermore, during the roasting process, the vanadium ore particles are first pre-roasted in the upper pre-roasting chamber and then roasted in the lower roasting chamber.

[0026] The pre-baking temperature in the upper pre-baking chamber is controlled at 300℃-400℃ for 3-5 hours.

[0027] The roasting temperature in the lower roasting chamber is controlled at 750℃-850℃, and the roasting time is 3-6 hours.

[0028] Furthermore, the carbon content in the vanadium ore particles is 4-9%;

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0030] (1) The vanadium ore roasting vertical kiln in this invention is a vertical kiln with an external heating source. Multiple sets of kiln internal combustion and external heating sources are set in the vertical kiln. The ratio of stone coal to stone coal vanadium ore in the kiln is about 20%. The heat of the stone coal vanadium ore itself is used for vanadium ore ball roasting (oxidative roasting), which saves a lot of energy and solves the problem of vertical kiln being environmentally unfriendly, and achieves the emission of waste gas in compliance with standards.

[0031] (2) The present invention is equipped with an air preheating chamber, which effectively utilizes the heat emitted by the gas generated by the gas generator to preheat the air (sometimes including oxygen) and send it into the roasting chamber, thereby accelerating the roasting speed and ensuring the uniformity of roasting. Attached Figure Description

[0032] The following figures are for illustrative purposes only and are not intended to limit the scope of the invention, wherein:

[0033] Fig. 1 : A schematic diagram of the kiln structure for vanadium ore roasting vertical kiln provided by the present invention;

[0034] Fig. 2 : A schematic diagram of the structure of the vertical kiln for vanadium ore roasting provided by the present invention;

[0035] In the diagram: 1-Flue gas passage, 2-Kiln body, 3-Furnace door, 4-Discharge chain plate, 5-Upper pre-calcining chamber, 6-Air preheating chamber, 7-Fire-permeable brick, 8-Lower calcining chamber, 9-Cooling chamber, 10-Temperature control device, 11-Induced draft fan, 12-Upper furnace bridge, 13-Lower furnace bridge, 14-Burner, 15-Insulation cotton. Detailed Implementation

[0036] To make the objectives, technical solutions, design methods, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention.

[0037] like Figs. 1-2 As shown, the present invention provides a vertical kiln for roasting vanadium ore.

[0038] Includes a vertical kiln body 2 and a temperature control device 10 for monitoring the temperature of the firing chamber inside the kiln body 2;

[0039] The kiln body 2 includes multiple interconnected kilns.

[0040] The top of the kiln body 2 is provided with a flue gas channel 1, and each group of kilns is provided with a flue gas channel 1 at the top, and an induced draft fan 11 is installed on the flue gas channel 1. The bottom of the kiln is provided with a cooling chamber 9, and a discharge chain plate 4 is installed in the cooling chamber 9. The kiln body 2 is provided with a furnace door 3 near the top wall that communicates with the feeding channel. The input end of the feeding channel is connected to a material distributor. The interior of the kiln between the furnace door 3 and the cooling chamber 9 is a firing chamber.

[0041] The discharge chain plate 4 is a rectangular connecting plate that covers the opening on the cooling chamber 9 and is connected to the cooling chamber 9 by a hinge. The outer side of the kiln body 2 surrounding the firing chamber is wrapped with a heat preservation device. An air preheating chamber 6 is provided on the inner side of the heat preservation device and the outer side of the kiln body 2. The air preheating chamber 6 is connected to the firing chamber through a fire-permeable brick 7.

[0042] The temperature control device 10 is installed inside the roasting chamber and the air preheating chamber 6.

[0043] The air preheating chamber 6 is also connected to the gas output end of the gas generator through a gas pipeline.

[0044] The roasting chamber includes a lower roasting chamber 8 and an upper pre-roasting chamber 5 arranged from bottom to top, and the lower roasting chamber 8 and the upper pre-roasting chamber 5 are separated by an upper furnace bridge 12. The lower roasting chamber 8 and the cooling chamber 9 are separated by a lower furnace bridge 13.

[0045] Furthermore, the fire-permeable brick 7 is a red brick and / or a refractory brick, and the fire-permeable brick 7 is provided with a number of ventilation holes for allowing preheated coal gas to enter the roasting chamber. The ventilation holes are located in the upper part of the lower roasting chamber 8 and the lower part of the upper pre-roasting chamber 5.

[0046] Furthermore, a burner 14 is provided on the outer wall of the air preheating chamber 6, and the gas supply pipe is sleeved on the burner 14. The air preheating chamber 6 is connected to the gas output end of the gas generator through the gas supply pipe on the burner 14.

[0047] The temperature control device 10 is a thermocouple, used to control the temperature of the firing chamber inside the kiln 2;

[0048] Furthermore, the kiln body 2 includes two sets of kilns connected by fire-permeable bricks 7. Both sets of kilns are constructed with a single layer of refractory bricks and concrete. The insulation device is wrapped around the outside of the two sets of kilns. The insulation device includes a metal shell and insulation cotton 15. The insulation cotton 15 is placed between the inner side of the metal shell and the outer side of the air preheating chamber 6.

[0049] Furthermore, adjacent kilns are equipped with air preheating chambers 6.

[0050] A method for roasting vanadium ore using a vertical kiln, the method comprising at least the following steps:

[0051] Step 1: The vanadium ore roasting material is pressed into vanadium ore particles with a moisture content of about 15% and a diameter of 30-40mm by the pelletizing machine and fed into the hopper of the cloth feeder.

[0052] Open furnace door 3, and the feeding conveyor, filled with vanadium ore particles, delivers the vanadium ore particles into the feed channel inside kiln body 2 via a belt conveyor, evenly distributing the vanadium ore particles in the hopper into the roasting chamber; close furnace door 3.

[0053] Step 2: Turn on the gas generator and send gas into the air preheating chamber 6. The gas is preheated in the air preheating chamber 6 to form preheated gas. At the same time, the heat emitted by the gas preheats the air (or oxygen) to form preheated air. The preheated gas and preheated air then enter the roasting chamber through the vent holes on the firebrick 7.

[0054] Step 3: Turn on the induced draft fan 11 to discharge the flue gas in the kiln body 2 to the flue gas treatment system (desulfurization tower spray) through the flue gas passage 1, and maintain the temperature of the firing chamber in the kiln body 2 at 300℃~800℃.

[0055] During the roasting process, the temperature inside the kiln is monitored by the temperature control device 10, and the wind speed and wind pressure of the induced draft fan 11 and the temperature of the gas generated by the gasifier entering the air preheating chamber 6 are adjusted by the temperature control device 10 to control the roasting temperature.

[0056] Vanadium ore particles are roasted in the upper pre-roasting chamber 5 and the lower roasting chamber 8. The temperature in the upper pre-roasting chamber 5 is controlled at 300℃-400℃ for 3-5 hours. The temperature in the lower roasting chamber 8 is controlled at 750℃-850℃ for 3-6 hours. After roasting, the vanadium ore particles in the roasting chamber are unloaded into the cooling chamber 9.

[0057] Step 4: After roasting, open the discharge chain plate 4 to transport the vanadium ore particles in the cooling chamber 9 out of the kiln body 2.

[0058] To maintain the normal operation of the gasifier and induced draft fan 11, start the temperature control device 10. The temperature control device 10 uses thermocouple detection to control the internal combustion of heat.

[0059] The temperature inside the kiln is monitored by the temperature control device 10, and the wind speed and wind pressure of the induced draft fan 11 and the temperature of the gas generated by the gas generator entering the air preheating chamber 6 are adjusted by the temperature control device 10 to ensure that the temperature in the roasting chamber is between 300℃ and 800℃. Steps one, two, five and six are repeated, and so on, until the vanadium ore roasting vertical kiln enters the normal continuous working state.

[0060] It is worth noting that the kiln body 2 utilizes external auxiliary heating from multiple sets of internal combustion furnaces and gas generators to burn vanadium shale oil with a carbon content of 4-9% within the kiln body 2. Since the vanadium ore particles entering the kiln body 2 are 30-40mm in size, particle size segregation occurs due to particle accumulation, forming airflow channels with a certain amount of moisture. This moisture is then introduced into the air preheating chamber 6 via the gas and then into the roasting chamber within the kiln body 2 through the permeable bricks 7. This causes heat to continuously accumulate inside the kiln body 2, generating a significant amount of heat (300-1000 Kcal / Kg). When the temperature reaches above 350 degrees Celsius, self-roasting of the vanadium shale oil is achieved. This prevents sintering within the kiln body 2, resulting in a high conversion rate of the vanadium shale oil. The multiple sets of internal combustion furnaces in the kiln body 2 are used for decarburization, and the heat generated from decarburization combustion further facilitates self-roasting and oxidation. The use of internal combustion significantly reduces the amount of waste gas produced after kiln roasting, with particulate matter emissions ≤50mg / m³. 3 Sulfur dioxide emissions ≤400mg / m³ 3， Nitrogen oxide emissions ≤240mg / m³ 3 This technology achieves compliant emissions of exhaust gas. In existing technologies, the two 3.4-meter gasifiers consume more than 60 tons of coal per day, resulting in an annual coal consumption of more than 18,000 tons. The two 3.4-meter gasifiers in this application consume only 40 tons of coal per day, saving more than 8,000 tons of standard coal per year. This demonstrates good energy conservation and consumption reduction. Furthermore, the SO2 and particulate matter in the exhaust gas from the combustion of hot coal gas meet the "Emission Standard of Pollutants for Vanadium Industry" (GB26452-2011), thus achieving compliant emissions.

[0061] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A vanadium ore roasting shaft kiln characterized in that, The vertical kiln body (2) and the temperature control device (10) for monitoring the temperature of the roasting chamber in the kiln body (2); The kiln body (2) comprises a plurality of groups of kilns which are connected to each other; The top of each group of kilns is provided with a flue gas passage (1), and an induced draft fan (11) is installed on the flue gas passage (1); the bottom of the kiln is provided with a cooling chamber (9), and a discharge chain plate (4) is installed in the cooling chamber (9); the kiln body (2) is provided with a furnace door (3) which is connected to a feeding passage on the wall near the top, and the input end of the feeding passage is connected to a cloth feeding machine; the inside of the kiln between the furnace door (3) and the cooling chamber (9) is a roasting chamber; The kiln body (2) around the roasting chamber is wrapped with a heat preservation device, and an air preheating cavity (6) is arranged between the inside of the heat preservation device and the outside of the kiln; the air preheating cavity (6) is connected to the roasting chamber through fire bricks (7); The temperature control device (10) is arranged in the roasting chamber and the air preheating cavity (6), The air preheating cavity (6) is also connected to the gas output end of a gas generator through a gas pipeline; The roasting chamber comprises a lower roasting chamber (8) and an upper pre-roasting chamber (5) which are arranged from bottom to top, and the lower roasting chamber (8) is separated from the upper pre-roasting chamber (5) by an upper furnace bridge (12); the lower roasting chamber (8) is separated from the cooling chamber (9) by a lower furnace bridge (13); A burner (14) is arranged on the outer wall of the air preheating cavity (6), the gas pipeline is sleeved on the burner (14), and the air preheating cavity (6) is connected to the gas output end of the gas generator through the gas pipeline on the burner (14); The kiln body (2) comprises at least two groups of kilns which are connected through the fire bricks (7), and each kiln is built by single-layer refractory bricks and concrete; a through hole is formed in the side wall of the kiln below the upper furnace bridge (12), the fire bricks (7) are installed in the through hole, the heat preservation device comprises a metal shell on the outside and heat preservation cotton (15) on the inside of the metal shell, and the heat preservation cotton (15) is arranged between the inside of the metal shell and the outside of the air preheating cavity (6); Adjacent kilns are provided with air preheating cavities (6).

2. The vertical roasting kiln for vanadium ore according to claim 1, characterized in that The fire bricks (7) are red bricks or / and refractory bricks, and a plurality of air holes are arranged on the fire bricks (7) to make preheated gas enter the roasting chamber; the air holes are arranged on the upper part of the lower roasting chamber (8) and the lower part of the upper pre-roasting chamber (5).

3. A vanadium ore roasting shaft kiln according to claim 1, characterized in that, The temperature control device (10) is a thermocouple.

4. A method for roasting vanadium ore in a vanadium ore roasting shaft kiln according to any one of claims 1 to 3, characterized in that, The method comprises at least the following steps: Step 1: vanadium ore particles are sent into the roasting chamber of the vertical kiln; the carbon content in the vanadium ore particles is 4-9%; Step 2: the gas generator is started, and gas is sent into the air preheating cavity (6); the gas is preheated in the air preheating cavity (6) to form preheated gas, and the heat emitted by the gas preheats air or oxygen to form preheated air; the preheated gas and the preheated air enter the roasting chamber through the air holes on the fire bricks (7) together; Step 3, start the air blower (11), through the flue gas passage (1) to discharge the flue gas in the kiln body (2) to the flue gas treatment system, and keep the temperature of the roasting chamber in the kiln body (2) at 300-800℃ to roast the vanadium ore particles; During the roasting process, the temperature in the kiln is monitored by the temperature control device (10), and the air speed and air pressure of the air blower (11) and the temperature of the coal gas entering the air preheating chamber (6) generated by the coal gas generator are adjusted by the temperature control device (10) to control the roasting temperature; During the roasting process, the vanadium ore particles are first pre-roasted in the upper pre-roasting chamber (5) and then roasted in the lower roasting chamber (8); The pre-roasting temperature in the upper pre-roasting chamber (5) is controlled at 300-400℃, and the time is 3-5 hours; The roasting temperature in the lower roasting chamber (8) is controlled at 750-850℃, and the roasting time is 3-6 hours; Step 4, after the roasting is completed, open the discharge chain plate (4) to transport the vanadium ore particles in the cooling chamber (9) out of the kiln body (2).

5. The method of claim 4, wherein, The particle size of the vanadium ore particles is 30-40mm.

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