Apparatus and method for sulfatizing roasting of ores

Abstract

The application provides a sulfating roasting device and method of ore and relates to the technical field of hydrometallurgy. The sulfating roasting device is used for sulfating roasting of ore, the function structure of a pulp preparation tank 3 is designed, and material is added in batches in a segmented manner, so that the pulp preparation time is shortened, the pulp preparation efficiency is improved, and the risk of pulp tank overflow is reduced. The process and equipment structure design are comprehensively adopted, such as multi-point feeding, a large amount of high-temperature dry material and wet material mixing, and the like, so that the material is rapidly solidified in the slurry solidifier, and the technical problems of large material conveying, large power consumption and large heat consumption of the sulfating roasting external circulation return material are solved. The high-temperature tail gas generated by the rotary kiln is used for the rapid solidification process of the slurry, so that the energy cascade utilization is realized, the heat utilization efficiency is improved, the total energy consumption and production cost of the sulfating roasting of the ore are reduced, the amount of waste gas is reduced, and the industrial production is suitable.

Description

Technical Field

[0001] This invention relates to the field of hydrometallurgical technology, specifically to an apparatus and method for sulfation roasting of ores. Background Technology

[0002] Currently, the industrially applied mixed rare earth concentrate processing technologies are the sulfuric acid process and the caustic soda process. The caustic soda process, due to its high operating costs, difficulty in large-scale production, and high concentrate grade requirements, is only used in 10% of Baotou mines. The high-temperature sulfuric acid roasting method, also known as the third-generation acid process, is now widely used, employing an internally heated rotary kiln. This method has low production costs and has been widely adopted in recent years, achieving certain economic benefits. However, the use of an internally heated rotary kiln can cause scaling and ring formation at the feed end, making continuous production impossible.

[0003] To address the aforementioned issues, Chinese patent CN111411219A discloses a method and apparatus for low-temperature acid roasting of rare earth concentrates. This method employs an external constant-temperature mixer for material mixing, followed by adding the mixture to a rotary acidifier for acidification. A portion of the rare earth acidified clinker generated during the acidification reaction is returned to the feed end of the indirect-heated rotary acidifier via a reverse conveying structure to mix with the raw acid material, thus resolving the scaling and ring formation issues at the feed end of the cylinder. However, this existing technology still uses a rotary acidification device, which is limited by the equipment's loading capacity, resulting in low processing capacity. Furthermore, the external circulation return method involves a large material conveying volume, leading to high power and heat consumption. Summary of the Invention

[0004] In view of this, the purpose of this invention is to provide an apparatus and method for sulfation roasting of ores. The sulfation roasting apparatus provided by this invention for sulfation roasting of ores has low energy consumption, large processing capacity, and eliminates the "overflow" phenomenon during the ore slurry preparation process, thus solving the technical problem of large-scale external circulation return material transportation and high power and heat consumption in sulfation roasting.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0006] This invention provides a sulfation roasting apparatus for ores, comprising:

[0007] Metering screw conveyor 2;

[0008] A pulping tank 3 is connected to the outlet of the metering screw conveyor 2. The pulping tank 3 includes a stirring tank, in which a stirrer and an acid spraying system 3-3 are installed. The stirrer includes a stirring shaft, an I-shaped paddle 3-1 connected to the top of the stirring shaft, and a propeller 3-2 connected to the bottom of the stirring shaft. A mineral powder inlet and an acid feed pipe are provided at the top of the pulping tank 3. The acid feed pipe is connected to the acid spraying system 3-3. A pulp outlet is provided at the bottom of the pulping tank 3. A first valve 9 is provided on the acid feed pipe.

[0009] A slurry solidifier 5 is connected to the slurry outlet of the slurry preparation tank 3. The slurry solidifier 5 includes a cylinder 5-1 and a stirring device 5-2 disposed inside the cylinder 5-1. The stirring device includes two hollow shafts and two hollow blades rotating in opposite directions. The slurry solidifier 5 is also provided with a feed pipe 5-3, a discharge pipe 5-4, and an air inlet 5-5. The feed pipe 5-3 is provided with more than three discharge ports.

[0010] The rotary kiln 7 is connected to the discharge pipe 5-4. The rotary kiln 7 is provided with a feed inlet, a clinker outlet and a roasting exhaust gas outlet. The roasting exhaust gas outlet is connected to the air inlet 5-5.

[0011] Preferably, the height-to-diameter ratio of the pulping tank 3 is 2 to 3.5:1;

[0012] The diameter ratio of the propeller 3-2 to the mixing tank is 0.3 to 0.5:1;

[0013] The ratio of the height of the I-shaped paddle 3-1 to the height of the material in the mixing tank is 0.3 to 1:1, the ratio of the length of the I-shaped paddle 3-1 to the diameter of the mixing tank is 0.6 to 0.8:1, and the distance between the installation height of the I-shaped paddle 3-1 and the top of the mixing tank is 0.3 to 0.5m.

[0014] Preferably, the number of discharge ports provided on the feed pipe 5-3 is 3 to 5, and the feed pipe 5-3 is horizontally arranged inside the slurry curing device 5.

[0015] Preferably, a second valve 10 and a feeding pump 4 are installed on the pipeline connecting the slurry outlet of the slurry tank 3 and the feed pipe 5-3.

[0016] Preferably, the discharge pipe 5-4 of the slurry solidifier 5 is connected to the feed inlet of the rotary kiln 7 via a screw conveyor 6.

[0017] Preferably, the roasting exhaust gas outlet of the rotary kiln 7 is connected to the air inlet 5-5 of the slurry solidifier 5 via a high-temperature fan 8.

[0018] This invention provides a sulfation roasting method for ores, using the sulfation roasting apparatus described in the above technical solution, comprising the following steps:

[0019] The first part of concentrated sulfuric acid is added to the pulping tank 3 through the acid feeding pipe and the acid spraying system 3-3. Under the first stirring condition, the mineral powder is added to the pulping tank 3 through the mineral powder inlet via the metering screw conveyor 2. At the same time, the second part of concentrated sulfuric acid is added through the acid spraying system 3-3. After the mineral powder is added, the remaining concentrated sulfuric acid is added through the acid spraying system 3-3 and stirred to obtain the slurry.

[0020] The slurry is fed into the slurry curing unit 5 and cured under stirring conditions to obtain a cured material.

[0021] The cured material is fed into the rotary kiln 7 through the discharge pipe 5-4 for sulfation roasting to obtain ore sulfation roasted material and roasting tail gas respectively; the roasting tail gas is sent to the slurry curing unit 5 for reuse in the curing step.

[0022] Preferably, the mass ratio of the mineral powder to the total amount of concentrated sulfuric acid is 1:0.8-2;

[0023] The first portion of concentrated sulfuric acid accounts for 50-80% of the total mass of concentrated sulfuric acid, the second portion of concentrated sulfuric acid accounts for 10-40% of the total mass of concentrated sulfuric acid, and the remaining concentrated sulfuric acid accounts for 10-25% of the total mass of concentrated sulfuric acid;

[0024] The concentrated sulfuric acid has a mass concentration of 90-98%.

[0025] The feeding time of the mineral powder is 10 to 40 minutes;

[0026] The remaining concentrated sulfuric acid is added over a period of 5 to 20 minutes.

[0027] The stirring speed under the first stirring condition is 350–600 rpm;

[0028] The mixing time is 5 to 20 minutes, and the mixing speed is 350 to 600 rpm.

[0029] Preferably, the temperature of the slurry curing device 5 is 180–260°C, and the curing time is 3–20 min;

[0030] The mass ratio of the slurry added to the slurry curing device 5 to the cured dry material present in the slurry curing device 5 is 0.1 to 0.4:1.

[0031] Preferably, the sulfation roasting temperature is 250–500°C and the time is 0.5–4 h.

[0032] The sulfation roasting apparatus for ore provided by this invention performs sulfation roasting of ore. Through the functional and structural design of the slurry preparation tank 3 and the control of processes such as segmented and batch-added material, the slurry preparation time is shortened, the slurry preparation efficiency is improved, and the risk of slurry overflow is reduced. By comprehensively adopting multi-point feeding (more than 3 discharge ports set on the feed pipe 5-3), large-scale mixing of high-temperature dry and wet materials, and other process and equipment structural designs, rapid solidification of materials in the slurry solidifier is achieved, solving the technical problems of large material transportation and high power and heat consumption in the external circulation return material transportation of sulfation roasting. The high-temperature tail gas generated by the rotary kiln is used in the rapid solidification process of the slurry, realizing the cascade utilization of energy, improving heat utilization efficiency, reducing the total energy consumption and production cost of ore sulfation roasting, reducing the amount of waste gas generated, and making it suitable for industrial production. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the sulfation roasting device for ore.

[0034] Figure 2 A detailed structural diagram of a slurry curing device;

[0035] Figures 1-2 In the diagram, 1 is the ore bin, 2 is the metering screw conveyor, 3 is the slurry tank, 3-1 is the I-shaped paddle, 3-2 is the propeller, 3-3 is the acid spraying system, 4 is the feeding pump, 5 is the slurry solidifier, 5-1 is the cylinder, 5-2 is the mixing device, 5-3 is the feed pipe, 5-4 is the discharge pipe, 5-5 is the air inlet, 6 is the screw conveyor, 7 is the rotary kiln, 8 is the high-temperature fan, 9 is the first valve, and 10 is the second valve. Detailed Implementation

[0036] This invention provides a sulfation roasting apparatus for ores, comprising:

[0037] Metering screw conveyor 2;

[0038] A pulping tank 3 is connected to the outlet of the metering screw conveyor 2. The pulping tank 3 includes a stirring tank, in which a stirrer and an acid spraying system 3-3 are installed. The stirrer includes a stirring shaft, an I-shaped paddle 3-1 connected to the top of the stirring shaft, and a propeller 3-2 connected to the bottom of the stirring shaft. A mineral powder inlet and an acid feed pipe are provided at the top of the pulping tank 3. The acid feed pipe is connected to the acid spraying system 3-3. A pulp outlet is provided at the bottom of the pulping tank 3. A first valve 9 is provided on the acid feed pipe.

[0039] A slurry solidifier 5 is connected to the slurry outlet of the slurry preparation tank 3. The slurry solidifier 5 includes a cylinder 5-1 and a stirring device 5-2 disposed inside the cylinder. The stirring device includes two hollow shafts and two hollow blades rotating in opposite directions. The slurry solidifier 5 is also provided with a feed pipe 5-3, a discharge pipe 5-4 and an air inlet 5-5. The feed pipe 5-3 is provided with more than three discharge ports.

[0040] A rotary kiln 7 is connected to the discharge pipe 5-4 of the slurry solidifier 5. The rotary kiln 7 is provided with a feed inlet, a clinker outlet and a roasting exhaust gas outlet.

[0041] Figure 1 This is a schematic diagram of a sulfation roasting apparatus for ore. Figure 2 The following is a detailed structural diagram of the slurry curing device, combined with... Figures 1-2 A detailed description of the sulfation roasting apparatus for ore is provided.

[0042] The sulfation roasting apparatus for ore provided by the present invention includes a metering screw conveyor 2, the function of which is to control the feeding speed and feeding amount of ore powder conveyed to the slurry tank 3.

[0043] The sulfation roasting apparatus for ore provided by the present invention preferably further includes a ore bin 1, the outlet of which is connected to a metering screw conveyor 2.

[0044] The sulfation roasting apparatus for ore provided by this invention includes a slurry tank 3, which includes a stirring tank containing a stirrer and an acid spraying system 3-3. The stirrer includes a stirring shaft, an I-shaped paddle 3-1 connected to the top of the stirring shaft, and a propeller 3-2 connected to the bottom of the stirring shaft. The top of the slurry tank 3 has a mineral powder inlet and an acid feed pipe, which is connected to the acid spraying system 3-3 and has a first valve 9. The bottom of the slurry tank 3 has a slurry outlet. The mineral powder inlet is connected to the outlet of a metering screw conveyor 2. Preferably, the bottom of the slurry tank 3 also has a valve, which allows the slurry to flow out through the slurry outlet when the valve is open. Preferably, the opening degree of the first valve 9 is 10-60%, more preferably 30-50%. This invention controls the rate of concentrated sulfuric acid addition by controlling the opening degree of the first valve 9. In this invention, the height-to-diameter ratio of the slurry tank 3 is preferably 2-3.5:1, more preferably 2.5-3:1; the diameter ratio of the propeller 3-2 to the mixing tank is preferably 0.3-0.5:1, more preferably 0.4-0.5:1; the height ratio of the I-shaped propeller 3-1 to the material height in the mixing tank is preferably 0.3-1:1, more preferably 0.5-0.8:1; the length ratio of the I-shaped propeller 3-1 to the diameter of the mixing tank is preferably 0.6-0.8:1, more preferably 0.7-0.8:1; the installation height of the I-shaped propeller 3-1 and the distance between the top of the mixing tank are preferably 0.3-0.5m, more preferably 0.3-0.4m, and even more preferably 0.3-0.35m; the installation height of the I-shaped propeller 3-1 is preferably above the material liquid surface in the mixing tank, and the I-shaped propeller 3-1 is used for defoaming.

[0045] The present invention uses the above-mentioned pulping tank 3 for pulping (mixing mineral powder and concentrated sulfuric acid), which can effectively eliminate the problem of foam overflow during the pulp preparation stage.

[0046] The sulfation roasting apparatus for ore provided by the present invention preferably further includes a feeding pump 4, which is installed on the pipeline connecting the second valve 10 and the feed pipe 5-3.

[0047] The sulfation roasting apparatus for ore provided by this invention includes a slurry solidifier 5. The slurry solidifier 5 includes a cylinder 5-1 and a stirring device 5-2 disposed within the cylinder 5-1. The stirring device includes two hollow shafts and two counter-rotating hollow blades. The slurry solidifier 5 is also provided with a feed pipe 5-3, a discharge pipe 5-4, and an air inlet 5-5. The feed pipe 5-3 has three or more discharge ports and is horizontally arranged within the slurry solidifier 5, serving as a horizontal feed pipe. The feed pipe 5-3 is connected to the slurry outlet of the slurry preparation tank 3. In this invention, the hollow blades are preferably wedge-shaped. In this invention, the hollow blades in the stirring device rotate to stir the slurry, enhance the heat transfer effect of the material, and simultaneously crush and grind the solidified material. The heating medium can enter the hollow blades through the hollow shaft to heat the slurry. The cylinder has a double-layer structure, and the heating medium can also be introduced into the inner sleeve to heat the slurry. The heating medium is the roasting exhaust gas generated by the rotary kiln 7. The device provided by this invention comprehensively adopts multi-point feeding, blade stirring, wedge blade coupling self-cleaning and other processes and equipment structures to achieve rapid solidification of the slurry and effectively solve the technical problems of large material transportation, high power and heat consumption in sulfation roasting external circulation return material transportation.

[0048] The sulfation roasting apparatus for ore provided by the present invention preferably further includes a screw conveyor 6, which is connected to the discharge pipe 5-4 of the slurry solidifier 5 and the feed inlet of the rotary kiln 7.

[0049] The sulfation roasting apparatus for ore provided by the present invention includes a rotary kiln 7, which is provided with a feed inlet, a clinker outlet, and a roasting tail gas outlet. The roasting tail gas outlet is connected to an air inlet 5-5, and preferably, the roasting tail gas outlet is connected to the air inlet 5-5 via a high-temperature fan 8. In the present invention, the rotary kiln is preferably heated by natural gas.

[0050] The sulfation roasting apparatus for ore provided by the present invention preferably further includes a tail gas treatment device connected to the slurry solidifier 5. In this invention, according to the tail gas flow direction, the tail gas treatment device preferably includes a top bag filter, a tail gas absorption tower, an induced draft fan, and a chimney connected in sequence. In this invention, the purpose of the tail gas treatment device is to purify the tail gas generated during slurry solidification and roasting.

[0051] The sulfation roasting apparatus for ore provided by the present invention further includes a clinker bin connected to the clinker outlet of the rotary kiln 7.

[0052] This invention provides a sulfation roasting method for ores, using the sulfation roasting apparatus described in the above technical solution, comprising the following steps:

[0053] The first part of concentrated sulfuric acid is added to the pulping tank 3 through the acid feeding pipe and the acid spraying system 3-3. Under the first stirring condition, the mineral powder is added to the pulping tank 3 through the mineral powder inlet via the metering screw conveyor 2. At the same time, the second part of concentrated sulfuric acid is added through the acid spraying system 3-3. After the mineral powder is added, the remaining concentrated sulfuric acid is added through the acid spraying system 3-3 and stirred to obtain the slurry.

[0054] The slurry is fed into the slurry curing unit 5 and cured under the second stirring condition to obtain a cured material.

[0055] The cured material is fed into the rotary kiln 7 through the discharge pipe 5-4 for sulfation roasting to obtain ore sulfation roasted material and roasting tail gas respectively; the roasting tail gas is sent to the slurry curing unit 5 for reuse in the curing step.

[0056] Unless otherwise specified, the materials and equipment used in this invention are all commercially available products in the field.

[0057] Preferably, the temperature of the slurry curing device 5 is 180-260°C, and the curing time is 3-20 min.

[0058] Preferably, the sulfation roasting temperature is 250–500°C and the time is 0.5–4 h.

[0059] In this invention, a first portion of concentrated sulfuric acid is added to a pulping tank 3 via an acid feeding pipe and an acid spraying system 3-3. Under a first stirring condition, mineral powder is added to the pulping tank 3 via a metering screw conveyor 2 and a mineral powder inlet. At the same time, a second portion of concentrated sulfuric acid is added via the acid spraying system 3-3. After the mineral powder is added, the remaining concentrated sulfuric acid is added via the acid spraying system 3-3 and stirred to obtain a slurry.

[0060] This invention does not specifically limit the mineral powder used; any mineral powder well-known to those skilled in the art can be used, such as a mixed rare earth concentrate powder composed of monazite and bastnaesite and / or a uranium-containing rare earth polymetallic concentrate powder. In specific embodiments of this invention, the mineral powder includes a rare earth concentrate powder containing hydroxysilicon-beryllium yttrium ore, bastnaesite, and monazite (preferably with a rare earth oxide content of 45 wt%), or a uranium-containing rare earth polymetallic concentrate powder (preferably with a uranium content of 0.156 wt%, a rare earth oxide content of 8 wt%, and a beryllium oxide content of 9.8 wt%), or a uranium-containing beryllium polymetallic concentrate powder (preferably with a uranium content of 0.13 wt% and a beryllium oxide content of 11.2 wt%). In this invention, the particle size of the mineral powder is preferably 0.04–0.2 mm, more preferably 0.074–0.1 mm.

[0061] In this invention, the mass ratio of the mineral powder to the total amount of concentrated sulfuric acid is preferably 1:0.8 to 2, more preferably 1:0.8 to 1.6, and specifically preferably 1:0.8, 1:1.0 or 1:1.6.

[0062] In this invention, the first portion of concentrated sulfuric acid preferably accounts for 50-80% of the total mass of concentrated sulfuric acid, more preferably 50%, 60%, or 70%; the second portion of concentrated sulfuric acid accounts for 10-40% of the total mass of concentrated sulfuric acid, more preferably 15% or 25%; and the remaining concentrated sulfuric acid accounts for 10-25% of the total mass of concentrated sulfuric acid, more preferably 15-25%, more preferably 15% or 25%. In this invention, the mass concentration of the concentrated sulfuric acid is preferably 90-98%, more preferably 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, or 98%.

[0063] In this invention, the stirring speed of the first stirring condition is preferably 350-600 rpm, more preferably 400-550 rpm, and even more preferably 450-500 rpm.

[0064] In this invention, the feeding time of the mineral powder and the second part of concentrated sulfuric acid is the same, preferably 10-40 min, more preferably 25-40 min, and specifically preferably 15 min, 20 min or 40 min.

[0065] In this invention, the addition time of the remaining concentrated sulfuric acid is preferably 5 to 20 minutes, more preferably 10 to 20 minutes, and even more preferably 10 minutes.

[0066] In this invention, the mixing time is preferably 5 to 20 minutes, more preferably 10 to 20 minutes, and even more preferably 5 minutes, 10 minutes or 20 minutes.

[0067] In this invention, the stirring and mixing time is preferably 5 to 20 minutes, more preferably 5 minutes, 10 minutes or 20 minutes; the stirring and mixing speed is preferably 350 to 600 rpm, more preferably 400 to 550 rpm, and even more preferably 450 to 500 rpm.

[0068] After obtaining the slurry, the present invention conveys the slurry to the slurry curing unit 5 and cures it under the second stirring condition to obtain a cured material. The heat of the curing is provided by the calcination exhaust gas generated by the rotary kiln 7.

[0069] In this invention, the mass ratio of the slurry added to the slurry curing unit 5 to the cured material inside the slurry curing unit 5 is preferably 0.1 to 0.4:1, more preferably 0.2 to 0.3:1. This invention controls the height of the cured dry material inside the slurry curing unit 5 by controlling the discharge pipe 5-4 (thus controlling the amount of cured dry material stored in the slurry curing unit 5), and simultaneously controls the slurry addition flow rate by the feeding pump 4, thereby achieving the correct mass ratio of slurry to cured material. This ensures that the amount of wet slurry added matches the amount of cured dry material present in the slurry curing unit 5, guaranteeing that the slurry and cured dry material mix and cure rapidly. Furthermore, this invention uses three or more discharge ports on the feed pipe 5-3 to disperse the feeding, and enhances the heat transfer process through stirring, achieving rapid mixing and curing of the material.

[0070] In this invention, the temperature of the slurry curing device 5 is preferably 180–260°C, specifically 180°C, 240°C, or 260°C; the curing time is preferably 3–20 min, specifically 3 min or 10 min; the rotation speed of the second stirring condition is preferably 30–200 rpm, more preferably 60–120 rpm. In this invention, the temperature of the heating medium in the slurry curing device 5 is preferably 200–300°C, specifically 200°C, 260°C, or 280°C. Controlling the heating medium temperature at 200–300°C in this invention helps control the feeding rate and ensures that the rapid curing temperature is 180–260°C.

[0071] After curing, the present invention preferably further includes treating the cured exhaust gas obtained by curing. The exhaust gas treatment is preferably performed by removing dust from a top bag filter, absorbing it through an exhaust gas absorption tower, and then discharging it from a chimney by an induced draft fan after meeting the standards.

[0072] After obtaining the solidified material, the present invention feeds the solidified material into the rotary kiln 7 through the discharge pipe 5-4 for sulfation roasting, to obtain ore sulfation roasting material and roasting tail gas respectively; the roasting tail gas is transported to the slurry solidifier 5 for reuse in the solidification step.

[0073] In this invention, the sulfation roasting temperature is preferably 250–500°C, more preferably 200–250°C, and specifically preferably 300°C, 320°C, or 500°C; the sulfation roasting time is preferably 0.5–4 hours, more preferably 1–3 hours, and even more preferably 2 hours. In this invention, the heat source of the rotary kiln 7 is preferably gas-fired heating, and the roasting exhaust gas is preferably transported to the slurry curing unit 5 via a high-temperature fan 8 for reuse in the curing step.

[0074] Compared with existing technologies, the device provided by this invention for sulfation roasting of ore improves the utilization efficiency of the pulping tank, avoids the large amount of material transported back from the external circulation of sulfation roasting, and reduces power and heat consumption.

[0075] To further illustrate the present invention, the apparatus and method for sulfation roasting of ore are described in detail below with reference to the accompanying drawings and embodiments, but these should not be construed as limiting the scope of protection of the present invention.

[0076] Example 1

[0077] A mixed rare earth concentrate consisting of monazite and bastnaesite, with a rare earth oxide content of 45 wt%.

[0078] The height-to-diameter ratio of the slurry tank 3 is 3.5:1. The lower part of the stirring shaft of the agitator is connected to the propeller 3-2, the diameter of which is 0.3 times the diameter of the mixing tank. The upper part of the stirring shaft is connected to the I-shaped paddle 3-1, the height of which is 1 times the height of the material layer in the mixing tank, the length of which is 0.8 times the diameter of the mixing tank, and the installation height is above the final liquid surface, 0.5m away from the top of the tank.

[0079] A slurry was prepared by mixing mineral powder (particle size 0.04–0.2 mm) and concentrated sulfuric acid (92 wt% concentration) at a mineral-to-acid mass ratio of 1:1.6. First, concentrated sulfuric acid was added to the slurry tank 3 via an acid feed pipe, amounting to 50 wt% of the total concentrated sulfuric acid. After the sulfuric acid was added, stirring was started. Mineral powder in the ore bin 1 was added to the slurry tank 3 via a metering screw conveyor 2, while simultaneously, 25 wt% of the total concentrated sulfuric acid was added via an acid spray system 3-3. The speed of the metering screw conveyor 2 (80 rpm) and the opening of the concentrated sulfuric acid valve 9 (50%) were controlled by coupling the screw conveyor to ensure the mineral powder addition and concentrated sulfuric acid spraying time was controlled to 40 minutes. During the addition process, the stirring speed of the slurry tank 3 was 450 rpm. After the mineral powder addition was complete, stirring was maintained, and the remaining concentrated sulfuric acid (25 wt%) was added via spraying over 10 minutes. After all the concentrated sulfuric acid was added, the stirrer continued stirring for another 10 minutes to obtain the slurry.

[0080] Open the bottom valve 10 of the pulping tank 3 and start the feeding pump 4. Spray the material onto the surface of the material through the feed pipe 5-3 located inside the slurry curing unit 5. The feed pipe 5-3 is placed horizontally inside the slurry curing unit 2, and three discharge ports are opened for material distribution. The speed of the feeding pump 4 is controlled by a frequency converter to ensure that the mass ratio of the wet slurry added to the cured hot dry material in the slurry curing unit 5 is 0.4. The double-blade spiral in the slurry curing unit 5 rotates at 60 rpm, allowing the slurry to contact and mix with the cured hot dry material, thereby achieving rapid curing. The heating medium temperature is 200℃, and the feeding speed is controlled to ensure that the temperature of the rapid curing unit is 180℃. The material curing time is approximately 3 minutes.

[0081] After solidification, the material is discharged from the outlet pipe of the slurry solidifier 5 and conveyed to the rotary kiln 7 via the screw conveyor 6 for sulfation roasting. The roasting temperature is 500℃ and the roasting time is 2 hours. After roasting, the clinker is directly fed into the clinker bin. The rotary kiln 7 is heated by gas, and the roasting exhaust gas is sent to the slurry solidifier 5 via a high-temperature fan for slurry solidification.

[0082] The exhaust gas from slurry solidification and high-temperature acid hydrolysis is treated by a bag filter, exhaust gas absorption tower, induced draft fan, and chimney before being discharged in compliance with standards.

[0083] Compared with existing technologies, this technology improves the utilization efficiency of the pulping tank, avoids the large amount of material transported from the external circulation return material during sulfation roasting, and reduces power and heat consumption.

[0084] Example 2

[0085] The concentrate contains uranium-bearing rare earth polymetallic minerals, with uranium content of 0.156 wt%, rare earth oxide content of 8 wt%, and beryllium oxide content of 9.8 wt%.

[0086] The height-to-diameter ratio of the slurry tank 3 is 2:1. The lower part of the stirring shaft of the agitator is connected to the propeller 3-2, the diameter of which is 0.4 times the diameter of the mixing tank. The upper part of the stirring shaft is connected to the I-shaped paddle 3-1, the height of which is 0.5 times the height of the material layer in the mixing tank, the length of which is 0.8 times the diameter of the mixing tank, and the installation height is above the final liquid surface, 0.3m away from the top of the tank.

[0087] A slurry was prepared by mixing mineral powder (particle size 0.04–0.2 mm) and concentrated sulfuric acid (95 wt% concentration) at a mineral-to-acid mass ratio of 1:1.0. First, concentrated sulfuric acid was added to the slurry tank via an acid feed pipe, amounting to 70 wt% of the total concentrated sulfuric acid. After the concentrated sulfuric acid was added, stirring was started. Mineral powder in ore bin 1 was added to the slurry tank via a metering screw conveyor 2, while simultaneously, 15 wt% of the total concentrated sulfuric acid was added via an acid spray system 3-3. The speed of the metering screw conveyor 2 was controlled at 60 rpm and the opening of the concentrated sulfuric acid valve 9 was set to 30%, ensuring the mineral powder addition and concentrated sulfuric acid spraying time was controlled to 20 minutes. During the addition process, the stirring speed of the slurry tank 3 was 500 rpm. After the mineral powder addition was complete, stirring was maintained, and the remaining concentrated sulfuric acid (15 wt%) was added via spraying over 10 minutes. After all the concentrated sulfuric acid was added, the stirrer continued stirring for another 10 minutes.

[0088] Open the bottom valve 10 of the pulping tank 3 and start the feeding pump 4. Spray the material onto the surface of the material through the feed pipe 5-3 located inside the slurry curing unit 5. The feed pipe 5-3 is placed horizontally inside the slurry curing unit, and three discharge ports are opened for material distribution. The speed of the feeding pump 4 is controlled by a frequency converter to ensure that the mass ratio of the wet slurry added to the cured hot dry material in the slurry curing unit is 0.2. The double-blade spiral in the slurry curing unit 5 rotates at 80 rpm, allowing it to contact and mix with the cured hot dry material, thereby achieving rapid curing. The heating medium temperature is 280℃, and the feeding speed is controlled to ensure that the temperature of the rapid curing unit is 260℃. The material curing time is approximately 3 minutes.

[0089] After solidification, the material is discharged from the outlet pipe of the slurry solidifier 5 and conveyed to the rotary kiln 7 via the screw conveyor 6 for sulfation roasting. The roasting temperature is 320℃ and the roasting time is 2 hours. After roasting, the clinker is directly fed into the clinker bin. The rotary kiln 7 is heated by gas, and the roasting exhaust gas is sent to the slurry solidifier 5 via a high-temperature fan for slurry solidification.

[0090] The exhaust gas from slurry solidification and high-temperature acid hydrolysis is treated by a bag filter, exhaust gas absorption tower, induced draft fan, and chimney before being discharged in compliance with standards.

[0091] Compared with existing technologies, this technology improves the utilization efficiency of the pulping tank, avoids the large amount of material transported from the external circulation return material during sulfation roasting, and reduces power and heat consumption.

[0092] Example 3

[0093] A certain uranium-beryllium polymetallic concentrate contains 0.13 wt% uranium and 11.2 wt% beryllium oxide.

[0094] The height-to-diameter ratio of the slurry tank 3 is 2.5:1. The lower part of the stirring shaft of the agitator is connected to the propeller 3-2, the diameter of which is 0.5 times the diameter of the mixing tank. The upper part of the stirring shaft is connected to the I-shaped paddle 3-1, the height of which is 0.4 times the height of the material layer in the mixing tank, the length of which is 0.7 times the diameter of the mixing tank, and the installation height is above the final liquid surface, 0.4m away from the top of the tank.

[0095] A slurry was prepared by mixing mineral powder (particle size 0.04–0.2 mm) and concentrated sulfuric acid (90 wt% concentration) at a mineral-to-acid mass ratio of 1:0.8. First, concentrated sulfuric acid was added to the slurry tank 3 via an acid feed pipe, amounting to 60 wt% of the total concentrated sulfuric acid. After the addition of concentrated sulfuric acid, stirring was started. Mineral powder in the ore bin 1 was added to the slurry tank 3 via a metering screw conveyor 2, while simultaneously, 25 wt% of the total concentrated sulfuric acid was added via an acid spray system 3-3. The speed of the metering screw conveyor 2 was controlled at 30 rpm and the opening of the concentrated sulfuric acid valve 9 was set to 40% to ensure the mineral powder addition and concentrated sulfuric acid spraying time was controlled to 15 minutes. During the addition process, the stirring speed of the slurry tank was 550 rpm. After the mineral powder addition was complete, stirring was maintained, and the remaining concentrated sulfuric acid (15 wt%) was added via spraying over a period of 10 minutes. After all the concentrated sulfuric acid was added, the stirrer continued stirring for another 5 minutes.

[0096] Open the bottom valve 10 of the pulping tank 3 and start the feeding pump 4. Spray the material onto the surface of the material through the feed pipe 5-3 located inside the slurry curing unit 5. The feed pipe 5-3 is placed horizontally inside the slurry curing unit 5, and five discharge ports are opened for material distribution. The speed of the feeding pump 4 is controlled by a frequency converter to ensure that the mass ratio of the wet slurry added to the curing hot dry material in the slurry curing unit is 0.3. The double-blade spiral in the slurry curing unit 5 rotates at 60 rpm to ensure contact and mixing with the curing hot dry material, thereby achieving rapid curing. The heating medium temperature is 260℃, and the feeding speed is controlled to ensure that the temperature of the rapid curing unit is 240℃. The material curing time is approximately 10 minutes.

[0097] After solidification, the material is discharged from the outlet pipe of the slurry solidifier 5 and conveyed to the rotary kiln 7 via the screw conveyor 6 for sulfation roasting. The roasting temperature is 300℃ and the roasting time is 2 hours. After roasting, the clinker is directly fed into the clinker bin. The rotary kiln 7 is heated by gas, and the roasting exhaust gas is sent to the slurry solidifier 5 via a high-temperature fan for slurry solidification.

[0098] The exhaust gas from slurry solidification and high-temperature acid hydrolysis is treated by a bag filter, exhaust gas absorption tower, induced draft fan, and chimney before being discharged in compliance with standards.

[0099] Compared with existing technologies, this technology improves the utilization efficiency of the pulping tank, avoids the large amount of material transported from the external circulation return material during sulfation roasting, and reduces power and heat consumption.

[0100] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, not all embodiments. People can obtain other embodiments based on the present invention without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A sulfation roasting apparatus for an ore, comprising: Metering screw conveyor (2); A slurry tank (3) is connected to the outlet of the metering screw conveyor (2). The slurry tank (3) includes a stirring tank, in which an agitator and an acid spraying system (3-3) are installed. The agitator includes an agitator shaft, an I-shaped paddle (3-1) connected to the top of the agitator shaft, and a propeller (3-2) connected to the bottom of the agitator shaft. The top of the slurry tank (3) is provided with a mineral powder inlet and an acid feed pipe, which is connected to the acid spraying system (3-3). The bottom of the slurry tank (3) is provided with a slurry outlet. A first valve (9) is provided on the acid feed pipe. A slurry solidifier (5) is connected to the slurry outlet of the slurry preparation tank (3). The slurry solidifier (5) includes a cylinder (5-1) and a stirring device (5-2) disposed inside the cylinder (5-1). The stirring device includes two hollow shafts and two hollow blades rotating in opposite directions. The slurry solidifier (5) is also provided with a feed pipe (5-3), a discharge pipe (5-4), and an air inlet (5-5). The feed pipe (5-3) is provided with more than three discharge ports. The number of discharge ports provided on the feed pipe (5-3) is 3 to 5. The feed pipe (5-3) is horizontally disposed inside the slurry solidifier (5). The discharge pipe (5-4) of the slurry solidifier (5) is connected to the feed inlet of the rotary kiln (7) through a screw conveyor (6). A rotary kiln (7) is connected to the discharge pipe (5-4). The rotary kiln (7) is provided with a feed inlet, a clinker outlet and a roasting tail gas outlet. The roasting tail gas outlet is connected to the air inlet (5-5).

2. The sulfation roasting apparatus according to claim 1, characterized in that, The height-to-diameter ratio of the pulping tank (3) is 2~3.5:1; The diameter ratio of the propeller (3-2) to the stirring tank is 0.3~0.5:1; The ratio of the height of the I-shaped paddle (3-1) to the height of the material in the mixing tank is 0.3~1:1, the ratio of the length of the I-shaped paddle (3-1) to the diameter of the mixing tank is 0.6~0.8:1, and the distance between the installation height of the I-shaped paddle (3-1) and the top of the mixing tank is 0.3~0.5m.

3. The sulfation roasting apparatus according to any one of claims 1 to 2, characterized in that, A second valve (10) and a feeding pump (4) are installed on the pipeline connecting the slurry outlet of the slurry tank (3) and the feed pipe (5-3).

4. The sulfation roasting apparatus according to claim 1, characterized in that, The roasting exhaust gas outlet of the rotary kiln (7) is connected to the air inlet (5-5) of the slurry solidifier (5) via a high-temperature fan (8).

5. A method for sulfation roasting of an ore, characterized in that, The sulfation roasting apparatus according to any one of claims 1 to 4 is used, comprising the following steps: The first part of concentrated sulfuric acid is added to the pulping tank (3) through the acid feeding pipe and the acid spraying system (3-3). Under the first stirring condition, the mineral powder is added to the pulping tank (3) through the mineral powder inlet via the metering screw conveyor (2). At the same time, the second part of concentrated sulfuric acid is added through the acid spraying system (3-3). After the mineral powder is added, the remaining concentrated sulfuric acid is added through the acid spraying system (3-3) and stirred to obtain the slurry. The slurry is fed into a slurry curing device (5) and cured under a second stirring condition to obtain a cured material; The cured material is fed into a rotary kiln (7) through a discharge pipe (5-4) for sulfation roasting to obtain ore sulfation roasted material and roasting tail gas respectively; the roasting tail gas is transported to a slurry curing unit (5) for reuse in the curing step.

6. The method according to claim 5, characterized in that, The mass ratio of the mineral powder to the total amount of concentrated sulfuric acid is 1:0.8~2; The first portion of concentrated sulfuric acid accounts for 50-80% of the total mass of concentrated sulfuric acid, the second portion of concentrated sulfuric acid accounts for 10-40% of the total mass of concentrated sulfuric acid, and the remaining concentrated sulfuric acid accounts for 10-25% of the total mass of concentrated sulfuric acid. The concentrated sulfuric acid has a mass concentration of 90-98%; The feeding time of the mineral powder is 10~40min; The remaining concentrated sulfuric acid is added over a period of 5 to 20 minutes. The stirring speed under the first stirring condition is 350~600 rpm; The mixing time is 5-20 minutes, and the mixing speed is 350-600 rpm.

7. The method according to claim 5, characterized in that, The temperature of the slurry curing device (5) is 180~260℃, and the curing time is 3~20min; The mass ratio of the slurry added to the slurry curing device (5) to the cured dry material present in the slurry curing device (5) is 0.1~0.4:

1.

8. The method according to claim 5, characterized in that, The sulfation roasting temperature is 250~500℃, and the time is 0.5~4h.

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