Mixing, drying and conveying system and mixing, drying and conveying method for rare earth ore concentrate

Abstract

The invention discloses a mixing, drying and conveying system for rare earth ore concentrate. The mixing, drying and conveying system comprises an ore concentrate metering and premixing unit, a feeding belt conveyor, a steam rotary dryer and a mixed material conveying unit. The concentrate metering and premixing unit is used for weighing the rare earth wet concentrate and the iron concentrate, premixing the weighed rare earth wet concentrate and the weighed iron concentrate in proportion, and conveying the premixed rare earth wet concentrate and the premixed iron concentrate to the feeding belt conveyor; the feeding belt conveyor is used for receiving the premixed materials and conveying the premixed materials to the steam rotary dryer; the steam rotary dryer is used for drying, stirring and mixing the premixed materials, and the dried mixed materials are conveyed into the mixed material conveying unit; and the mixed material conveying unit is used for storing the dried mixed material or conveying the dried mixed material to a roasting kiln. The invention further discloses a mixing, drying and conveying method for the rare earth ore concentrate. Continuous conveying and accurate metering of rare earth ore concentrate and iron ore concentrate can be achieved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of rare earth concentrate wet smelting, and particularly relates to a rare earth concentrate mixing, drying and conveying system and a mixing, drying and conveying method. BACKGROUND

[0002] In the rare earth concentrate wet smelting process, wet concentrate (water content of about 15%) containing a certain amount of water, iron concentrate powder and concentrated sulfuric acid are used for high-temperature roasting to prepare rare earth sulfate. Due to the high water content of the rare earth concentrate, the viscosity of the concentrate is increased, the flowability is poor, and the concentrate is easy to cake. A large amount of concentrate is adhered to the pipe wall of the pipe chain machine and the pipe chain machine support sheet and cannot be removed, which reduces the pipe chain conveying efficiency and reduces the production efficiency.

[0003] In addition, due to the change of the water content of the concentrate within a certain range, the concentrate metering is not accurate, which affects the decomposition effect of the rare earth concentrate. If the water content of the concentrate is too high, the use amount of sulfuric acid and natural gas in the roasting process is increased, the amount of flue gas in the roasting process is increased, the material consumption and energy consumption in the roasting process are increased, the treatment capacity of the kiln tail flue gas treatment facility is increased, and thus the process operation cost is increased.

[0004] The rare earth concentrate smelting process usually uses iron concentrate powder and rare earth concentrate to mix, and then uses concentrated sulfuric acid to roast and remove phosphorus to improve the recovery rate of rare earth. However, since the rare earth concentrate and the iron concentrate are both solid particle powders, the mixing uniformity is poor, which causes the poor phosphorus removal effect of the rare earth concentrate and the low recovery rate of the rare earth.

[0005] Chinese Patent Publication No. CN105251405A discloses a dry powder mixing and conveying system, which belongs to the field of building materials. The system includes a spiral mixer and a plurality of storage bins. The storage bin includes a storage tank and a conveying pipe. The conveying pipe is inclined. The outlet of the storage tank is connected to the conveying pipe. The inlet of the spiral mixer is provided with a feeding device. The feeding device includes a shell, a stirring roller and a magnetic member. The upper and lower ends of the shell are respectively provided with a feeding port and a discharging port. The stirring roller is arranged in the middle of the shell. The upper end of the stirring roller is provided with a conical cap. The lower end of the stirring roller is connected to a motor. The magnetic member is arranged on the inner wall of the shell. The brim of the conical cap extends out of the outer wall of the stirring roller. The magnetic member and the stirring roller form a channel for the dry powder to pass through. The lower end of the conveying pipe is provided with a fan. The upper end of the conveying pipe is located at the feeding port. The discharging port is connected to the spiral mixer. Since the water content of the rare earth concentrate is large, the fan cannot blow away the caked rare earth concentrate. The spiral mixer will cause the rare earth concentrate to cake again. Although the addition amount of the dry powder is controlled, the material is not metered, which easily causes large fluctuations in the material ratio and makes it difficult to achieve accurate mixing.

[0006] Chinese Publication No. CN110736307A discloses a multi-stage drying method for water-selected concentrate, the steps of which are as follows: first, the separated concentrate is output to the hopper by the beneficiation equipment and falls into the transport belt through the output port of the hopper, and then falls into the funnel through the output end of the transport belt and is discharged into the dehydration disc through the output port of the funnel; second, the first-stage drying mechanism receives the wet concentrate delivered by the input device, performs centrifugal dehydration and preliminary drying treatment on the concentrate, and then discharges it into the air drying mechanism; then, the air drying mechanism performs air drying treatment on the preliminary drying treated concentrate, and then discharges it into the second-stage drying mechanism; then, the second-stage drying mechanism receives the air dried concentrate, performs secondary drying treatment on the concentrate, and then discharges it into the output device; finally, the discharge pipe discharges the dried concentrate to the input port of the discharge channel, and the concentrate slides down step by step along the jump plate until it is discharged from the output end of the discharge channel. Although a multi-stage drying process is provided to ensure the drying effect of the concentrate, the process design is relatively complex and the operation difficulty is relatively large, which has no practical value.

[0007] Chinese Publication No. CN213020863U discloses a concentrate drying and dust removal system, which comprises a pellet concentrate dryer, an input conveying device and an output conveying device arranged at the input end and the output end of the pellet concentrate dryer respectively, a hot blast furnace connected to the input end of the pellet concentrate dryer, and a dust removal device connected to the output end of the pellet concentrate dryer. The dust removal device comprises a flue gas pipe, an ash chute, a dust remover and a chimney assembly. The lower end of the flue gas pipe is connected to the output end of the pellet concentrate dryer, and the upper end is connected to the air inlet end of the dust remover. The upper end of the ash chute is connected to the dust outlet of the dust remover, and the lower end is connected to the output conveying device. The chimney assembly is connected to the exhaust port of the dust remover. This technology adopts an internal heating drying process. The cylinder dryer directly contacts the material with the hot carrier (hot air, flue gas) to dry the material. The waste air needs to be recovered by the cyclone dust collector before being vented, which increases the tail gas treatment process and the process operation cost. SUMMARY

[0008] The purpose of the present application is to provide a rare earth concentrate mixing, drying and conveying system and method, which can realize continuous conveying and accurate metering of rare earth concentrate and iron concentrate.

[0009] To achieve the above-mentioned purpose, the technical solution used by the present application is as follows:

[0010] The rare earth concentrate mixing, drying and conveying system comprises a concentrate metering and premixing unit, a feeding belt conveyor, a steam rotary dryer and a mixed material conveying unit.

[0011] The concentrate metering and premixing unit is used to weigh the rare earth wet concentrate and the iron concentrate powder, and premix the weighed rare earth wet concentrate and iron concentrate powder according to a certain proportion. The premixed rare earth wet concentrate and iron concentrate powder are conveyed to the feeding belt conveyor.

[0012] The upper feeding belt conveyor is used for receiving the premixed material and conveying the premixed material to the steam rotary dryer.

[0013] The steam rotary dryer is used for drying and mixing the premixed material, and the dried premixed material is sent to the mixed material conveying unit.

[0014] The mixed material conveying unit is used for storing the dried premixed material or conveying the dried premixed material to the calcination kiln.

[0015] Further, the concentrate metering premixing unit comprises a concentrate receiving hopper, an iron concentrate receiving hopper, a first fully-closed quantitative belt scale, and a second fully-closed quantitative belt scale. The feeding port at the top of the first fully-closed quantitative belt scale is located at the bottom of the concentrate receiving hopper, the feeding port at the top of the second fully-closed quantitative belt scale is located at the bottom of the iron concentrate receiving hopper, and the discharging ports at the top of the first and second fully-closed quantitative belt scales are located above the upper feeding belt conveyor. The concentrate receiving hopper is used for containing rare earth wet concentrate, the iron concentrate receiving hopper is used for containing iron concentrate, the first fully-closed quantitative belt scale is used for weighing the rare earth wet concentrate and discharging the rare earth wet concentrate of a set weight from the discharging port to the upper feeding belt conveyor, and the second fully-closed quantitative belt scale is used for weighing the iron concentrate and discharging the iron concentrate of a set weight from the discharging port to the upper feeding belt conveyor.

[0016] Further, the rare earth wet concentrate and the iron concentrate are weighed by the first and second fully-closed quantitative belt scales arranged at the lower parts of the concentrate receiving hopper and the iron concentrate receiving hopper, respectively, so as to realize proportional feeding of the rare earth wet concentrate and the iron concentrate to the upper feeding belt conveyor, realize metering and proportional premixing of the wet concentrate and the iron concentrate, and realize a conveying capacity of 15-25 t / h of the first and second fully-closed quantitative belt scales.

[0017] Further, the premixed material enters the steam rotary dryer from the feeding port at the kiln tail, the premixed material is discharged from the discharging port at the low part of the kiln head after drying, the generated moisture is discharged from the exhaust port, and the premixed material is mixed again during the drying process of the premixed material.

[0018] Further, the cylinder of the steam rotary dryer is arranged in an inclined manner, the kiln head on the right side is provided with a discharging port, the kiln tail on the left side is provided with a feeding port, the steam heating pipelines are arranged in a concentric manner in the cylinder, one end of the steam heating pipelines is installed on the distribution chamber at the discharging port, and the other end of the steam heating pipelines is installed on the bracket at the feeding port.

[0019] Further, the mixture conveying unit comprises a bucket elevator, a transfer bin, a pneumatic conveying device and a buffer bin, the bucket elevator is used to convey the mixture to the standby bin, the transfer bin is used to store the dried mixture, the pneumatic conveying device is used to convey the mixture to the buffer bin outside the roasting workshop, and the buffer bin is used to store the dried mixture.

[0020] Further, the bucket elevator is a Z-type bucket elevator, and the pneumatic conveying device adopts negative pressure conveying.

[0021] The method comprises the following steps:

[0022] The wet rare earth concentrate and the iron concentrate are weighed and premixed, and the premixed material is fed into a steam rotary dryer.

[0023] The steam rotary dryer dries and mixes the premixed material, and the dried mixture is discharged from a discharge port and fed into a mixture conveying unit.

[0024] The mixture is fed into a roasting kiln through the mixture conveying unit.

[0025] Preferably, the wet rare earth concentrate and the iron concentrate are fed into a concentrate receiving hopper and an iron concentrate receiving hopper respectively, weighed by a first fully-closed quantitative belt scale arranged at the lower part, fed into an upper feeding belt conveyor below at a set ratio, weighed by a second fully-closed quantitative belt scale, fed into the upper feeding belt conveyor below at a set ratio, and premixed in the upper feeding belt conveyor. The premixed material is fed into the steam rotary dryer from a feed port at the kiln tail of the steam rotary dryer, and the premixed material is mixed again with the rotation of the steam rotary dryer, dried by the internal steam heating pipeline, and moved to the discharge port at the low part of the kiln head under the action of gravity. After the dried mixture is discharged from the discharge port, the mixture falls into the bucket elevator, is lifted by the bucket elevator, and is conveyed to the transfer bin. The mixture is fed out from the discharge port at the lower part of the transfer bin according to the required amount, is aerated and fed to the buffer bin by the pneumatic conveying device, and the buffer bin opens the discharge port and inputs the mixture to the feeding device below according to the instruction. The feeding device conveys the mixture to the pipe chain machine of the roasting kiln.

[0026] Preferably, the saturated steam pressure during the drying process of the premixed material is 0.5-0.8 MPaG, and the saturated steam temperature is 140-180 DEG C. The drying time of the premixed material in the steam rotary dryer is 10-30 min, and the moisture content of the premixed material after drying is less than 5%.

[0027] The technical effects of the present application include:

[0028] The rare earth concentrate and the iron concentrate can be continuously conveyed and accurately metered, the amount of flue gas is reduced, the operation cost is reduced, and the rare earth concentrate processing capacity is improved.

[0029] 1、The rare earth concentrate can be automatically and accurately metered, the continuous automation level of the equipment can be improved, and the labor intensity of workers is reduced.

[0030] The fully-closed quantitative belt scale and the belt machine are adopted, the metering and premixing system of the rare earth concentrate and the iron concentrate powder is optimized, accurate metering of raw materials is realized, material mixing efficiency is improved, dust emission in the metering and conveying process of fine particles is solved, and environmental pollution is eliminated.

[0031] 2、The external heating type indirect continuous drying process is used in the concentrate drying system, the material entering the dryer is heated, dried, stirred and mixed, the dried material is discharged from the low discharge port, and the generated moisture is discharged from the exhaust port. No secondary wind dust pollution, no flue gas is generated, the amount of evaporated moisture is small. Thus, the water content of the rare earth concentrate is reduced, the consumption of sulfuric acid and natural gas in the subsequent rotary kiln is reduced, the tail gas treatment amount of the rotary kiln is reduced, the energy consumption of the subsequent process is reduced, the production cost of the enterprise is reduced, and the comprehensive competitiveness of the enterprise is increased.

[0032] 3、The pneumatic conveying system adopts negative pressure conveying, has good sealing performance, and is safe and efficient in the production process. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 is a structural principle diagram of the rare earth concentrate mixing, drying and conveying system provided by the application. DETAILED DESCRIPTION

[0034] The following description fully illustrates specific embodiments of the application to enable one of ordinary skill in the art to practice and reproduce the application. In order to make the purpose, technical solutions and advantages of the embodiments of the application clearer, the technical solutions in the embodiments of the application will be described clearly and completely below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the application. Therefore, the following detailed description of the embodiments of the application provided in the drawings is not intended to limit the scope of the claimed application, but only represents selected embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the application.

[0035] In the description of the present application, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship when the product of the present application is usually placed, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", "third" and the like are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0036] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "arrangement", "installation", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0037] As Figure 1 shown is a structural principle diagram of the rare earth concentrate mixing, drying and conveying system provided by the present application.

[0038] The rare earth concentrate mixing, drying and conveying system comprises: a concentrate metering and premixing unit 1, a feeding belt conveyor 2, a steam rotary dryer 3, and a mixed material conveying unit 4.

[0039] The concentrate metering and premixing unit 1 is used for weighing rare earth wet concentrate and iron concentrate powder, pre-mixing the weighed rare earth wet concentrate and iron concentrate powder according to a proportion, and conveying the pre-mixed rare earth wet concentrate and iron concentrate powder to the feeding belt conveyor 2.

[0040] The concentrate metering and premixing unit 1 comprises: a concentrate receiving hopper 11, an iron concentrate powder receiving hopper 12, a first fully-closed quantitative belt scale 13, and a second fully-closed quantitative belt scale 14. The feeding port at the top of the first fully-closed quantitative belt scale 13 is located at the bottom of the concentrate receiving hopper 11, the feeding port at the top of the second fully-closed quantitative belt scale 14 is located at the bottom of the iron concentrate powder receiving hopper 12, and the discharging ports at the top of the first fully-closed quantitative belt scale 13 and the second fully-closed quantitative belt scale 14 are located above the feeding belt conveyor 2. The concentrate receiving hopper 11 is used for containing rare earth wet concentrate, the iron concentrate powder receiving hopper 12 is used for containing iron concentrate powder, the first fully-closed quantitative belt scale 13 is used for weighing rare earth wet concentrate and discharging the rare earth wet concentrate of a set weight from the discharging port to the feeding belt conveyor 2, and the second fully-closed quantitative belt scale 14 is used for weighing iron concentrate powder and discharging the iron concentrate powder of a set weight from the discharging port to the feeding belt conveyor 2.

[0041] The rare earth wet concentrate and the iron concentrate are weighed by the first fully-closed quantitative belt scale 13 and the second fully-closed quantitative belt scale 14 arranged at the lower part of the concentrate receiving hopper 11 and the iron concentrate receiving hopper 12 respectively, the rare earth wet concentrate and the iron concentrate are independently weighed by the first fully-closed quantitative belt scale 13 and the second fully-closed quantitative belt scale 14 respectively, the rare earth wet concentrate and the iron concentrate are transported to the feeding belt conveyor 2 in proportion, and the wet concentrate and the iron concentrate are metered and pre-mixed in proportion.

[0042] The first fully-closed quantitative belt scale 13 and the second fully-closed quantitative belt scale 14 can not only uniformly and continuously transport the materials in the fully-closed state, but also can measure the materials in the furnace and effectively prevent the dust from overflowing, and the conveying capacity is 15-25t / h.

[0043] The feeding belt conveyor 2 is used for receiving the pre-mixed materials (the pre-mixed rare earth wet concentrate and the iron concentrate) and transporting the pre-mixed materials to the steam rotary dryer 3.

[0044] The steam rotary dryer 3 is used for drying and stirring the pre-mixed materials, and the mixed materials are sent to the mixed material conveying unit 4. The wet pre-mixed materials enter the steam rotary dryer 3 from the feeding port at the kiln tail, the pre-mixed materials are discharged from the discharging port at the low part of the kiln head after being dried, the evaporated moisture is discharged from the exhaust port, and the pre-mixed materials are mixed again during the drying process of the pre-mixed materials.

[0045] The steam rotary dryer 3 has no secondary dust pollution and no flue gas generation, the amount of evaporated moisture is small, and the steam rotary dryer 3 has the advantages of large treatment capacity, fast drying speed and low energy consumption. The steam rotary dryer 3 can reduce the production cost and is an environmentally-friendly drying equipment which can adapt to the large-flow drying of the ore powder and reduce the energy consumption.

[0046] The main body of the steam rotary dryer 3 is a slightly inclined and rotatable cylinder, the kiln head (right side) is provided with a discharging port, and the kiln tail (left side) is provided with a feeding port. The steam heating pipe is arranged in the cylinder in a concentric manner, one end of the steam heating pipe is installed on the distribution chamber at the discharging port, and the other end is installed on the bracket at the feeding port by a heat-expandable structure. The steam (hot water or heat-conducting oil) enters the steam heating pipe through the distribution chamber, the wet material is added into the cylinder through the feeding port, and the wet material moves from the high end to the low end under the action of gravity and exchanges heat with the steam heating pipe to complete the drying. The secondary steam generated by heating the wet material is discharged through the exhaust port, the dust collector and the induced draft fan, the dust carried by the secondary steam is captured and recovered in the dust collector, and the condensate water generated by the drying system is returned to the production system for standby.

[0047] The saturated steam pressure during the drying of the pre-mixed material is 0.5-0.8 MPaG (preferably 0.6 MPaG), and the saturated steam temperature is 140-180℃ (preferably 159℃); the drying time of the pre-mixed material in the steam rotary dryer 3 is 10-30 min; and the moisture content of the dried pre-mixed material is <5%.

[0048] The mixed material conveying unit 4 is used to store the dried mixed material or to convey the dried mixed material to the roasting kiln.

[0049] The mixed material conveying unit 4 comprises a bucket elevator 41, a transfer bin 42, a pneumatic conveying device 43, and a buffer bin 44. The bucket elevator (bucket elevator) 41 is used to convey the mixed material to the standby bin 42, the transfer bin 42 is used to store the dried mixed material, the pneumatic conveying device 43 is used to convey the mixed material to the buffer bin 44 outside the roasting workshop, and the buffer bin 44 is used to store the dried mixed material.

[0050] The bucket elevator (bucket elevator) 41 comprises a hopper, a bucket elevator composed of a hopper, a driving device, top and bottom rollers (or chain wheels), a belt (or traction chain), a tensioning device, and a machine shell, etc. The bucket elevator 41 is a vertical lifting material conveying device, which is suitable for lifting from low to high, and can adjust the conveying speed according to the conveying amount and select the lifting height as needed.

[0051] The bucket elevator 41 is a Z-type bucket elevator, and the pneumatic conveying device 43 adopts negative pressure conveying, which has good sealing performance, safe and efficient production process, and can further loosen the particles of the mixed material, facilitating subsequent feeding.

[0052] After the dried mixed material is discharged from the discharge port of the steam rotary dryer 3, it is conveyed to the dry concentrate transfer bin 42 by the Z-type bucket elevator 41, and then conveyed to the buffer bin 44 outside the roasting workshop by the pneumatic conveying device 43 arranged below the transfer bin 42. The dried concentrate is then fed into the feeding facility pipe chain machine of the roasting kiln through the feeding equipment 45 arranged below the buffer bin 44.

[0053] The feeding equipment 45 is used to convey the mixed material to the roasting kiln, and the feeding equipment 45 is a pipe chain machine.

[0054] Pipe chain conveyor (pipe chain machine) is used for the continuous conveying equipment of the powder, small granular and small block bulk materials, can carry on the horizontal, inclined and vertical combination three-dimensional conveying. In the closed pipeline, the chain piece is the transmission member to drive the material to move along the pipeline. When horizontal conveying, the mixture material particles are pushed by the chain piece in the moving direction. When the internal friction between the material layers is greater than the external friction of the material and the pipe wall, the material moves forward with the chain piece to form a stable material flow; when vertical conveying, the material particles in the pipe are pushed upward by the chain piece. Because the lower feeding prevents the upper material from sliding downward, the lateral side pressure is generated, so the internal friction of the material is enhanced. When the internal friction between the materials is greater than the external friction of the material and the pipe wall and the weight of the material, the material is conveyed upward with the chain piece to form a continuous material flow.

[0055] The selected rare earth wet concentrate and iron concentrate powder (water content of about 15%) are respectively sent into the concentrate receiving hopper 11 and the iron concentrate powder receiving hopper 12. The first fully-closed quantitative belt scale 13 weighs the rare earth wet concentrate and sends the rare earth wet concentrate into the lower feeding belt conveyor 2 according to the set proportion. The second fully-closed quantitative belt scale 14 weighs the iron concentrate powder and sends the iron concentrate powder into the lower feeding belt conveyor 2 according to the set proportion. The wet concentrate and the iron concentrate powder are pre-mixed in the feeding belt conveyor 2 according to the proportion, and then are sent into the steam rotary dryer 3. The steam rotary dryer 3 rotates, and the wet concentrate and the iron concentrate powder are mixed and dried in the steam rotary dryer 3. The mixed material moves to the discharge port at the low end of the steam rotary dryer 3 (the steam rotary dryer 3 is arranged obliquely) under the gravity, and the dried mixed material is discharged from the discharge port and falls into the hopper of the bucket elevator 41. The bucket elevator 41 sends the mixed material to the transfer bin 42. The mixed material is sent to the buffer bin 44 through the pneumatic conveying device 43. When feeding is needed, the mixed material is sent to the roasting kiln through the feeding equipment 45 of the roasting kiln for roasting.

[0056] The rare earth concentrate mixing, drying and conveying method specifically includes the following steps.

[0057] Step 1: The rare earth wet concentrate and the iron concentrate powder are weighed and pre-mixed. The pre-mixed material is sent into the steam rotary dryer 3.

[0058] The water content of the selected rare earth wet concentrate and the iron concentrate powder is about 15%. The rare earth wet concentrate and the iron concentrate powder are respectively sent into the concentrate receiving hopper 11 and the iron concentrate powder receiving hopper 12. The first fully-closed quantitative belt scale 13 arranged below weighs the rare earth wet concentrate and sends the rare earth wet concentrate into the lower feeding belt conveyor 2 according to the set proportion. The second fully-closed quantitative belt scale 14 weighs the iron concentrate powder and sends the iron concentrate powder into the lower feeding belt conveyor 2 according to the set proportion. The rare earth wet concentrate and the iron concentrate powder are pre-mixed in the feeding belt conveyor 2.

[0059] Step 2: The steam rotary dryer 3 dries and mixes the premixed materials. The dried mixture is discharged from the outlet and enters the mixture conveying unit 4.

[0060] The premixed materials enter the rotary steam dryer 3 through the feed inlet at the kiln tail. As the rotary steam dryer 3 rotates, the premixed materials are mixed again. The internal steam heating pipes dry the premixed materials. The dried mixture moves to the discharge port at the bottom of the kiln head under its own weight and is discharged. The moisture content of the dried mixture is about 4.50%. The condensate generated by the rotary steam dryer 3 is returned to the production system for later use.

[0061] Step 3: The mixture is fed into the firing kiln through the mixture conveying unit 4.

[0062] After drying, the mixture is discharged from the outlet and falls into the bucket elevator 41. After being lifted by the bucket elevator 41, it is transported to the transfer bin 42. The discharge port at the bottom of the transfer bin 42 discharges the mixture according to the required amount. The mixture is aerated and loosened by the pneumatic conveying device 43 and sent to the buffer bin 44 to improve the fluidity of the mixture. After receiving the instruction, the discharge port of the buffer bin 44 opens and inputs the mixture into the feeding device 45 below. The feeding device 45 conveys the mixture to the feeding facility of the calcining kiln, the tubular chain conveyor.

[0063] The terminology used in this invention is descriptive and exemplary, not restrictive. Since this invention can be embodied in many forms without departing from the spirit or essence of the technical solution, it should be understood that the above embodiments are not limited to any of the foregoing details, but should be interpreted broadly within the spirit and scope defined by the appended claims. Therefore, all variations and modifications falling within the scope of the claims or their equivalents should be covered by the appended claims.

Claims

1. A blended dry conveying system of rare earth concentrates, characterized by, The application relates to a rare earth concentrate metering and premixing unit and a method thereof. The application relates to a rare earth concentrate metering and premixing unit and a method thereof. The rare earth concentrate metering and premixing unit is used for weighing rare earth wet concentrates and iron concentrates, and the weighed rare earth wet concentrates and iron concentrates are premixed in proportion and then delivered to the feeding belt conveyor. The feeding belt conveyor is used for receiving the premixed materials and delivering the premixed materials to the steam rotary dryer. The steam rotary dryer is used for drying and stirring the premixed materials, and the dried mixed materials are delivered to the mixed material conveying unit. The mixed material conveying unit is used for storing the dried mixed materials or delivering the dried mixed materials to the roasting kiln. The rare earth concentrate metering and premixing unit comprises a concentrate receiving hopper, an iron concentrate receiving hopper, a first fully-closed quantitative belt scale and a second fully-closed quantitative belt scale.

2. The system for dry conveying of mixtures of rare earth concentrates according to claim 1, characterized in that, The first fully-closed quantitative belt scale is used for weighing the rare earth wet concentrates and discharging the rare earth wet concentrates with a set weight from a discharge port to the feeding belt conveyor.

3. The system for dry conveying of a mixture of rare earth concentrates of claim 2, wherein, The second fully-closed quantitative belt scale is used for weighing the iron concentrates and discharging the iron concentrates with a set weight from a discharge port to the feeding belt conveyor.

4. The system for dry conveying of mixtures of rare earth concentrates of claim 1, wherein, The rare earth wet concentrates and the iron concentrates are weighed by the first fully-closed quantitative belt scale and the second fully-closed quantitative belt scale arranged at the lower parts of the concentrate receiving hopper and the iron concentrate receiving hopper respectively, and then the rare earth wet concentrates and the iron concentrates are delivered to the feeding belt conveyor in proportion, so that the weighing and proportional premixing of the wet concentrates and the iron concentrates are realized.

5. The system for dry conveying of mixtures of rare earth concentrates of claim 1, wherein, The delivery capacity of the first fully-closed quantitative belt scale and the second fully-closed quantitative belt scale is 15-25t / h.

6. The system for dry conveying of mixtures of rare earth concentrates of claim 1, wherein, The premixed materials enter the steam rotary dryer from a feeding port at the kiln tail, and the dried premixed materials are discharged from a discharge port at the kiln head, and the generated moisture is discharged from an exhaust port.

7. The system for dry conveying of mixtures of rare earth concentrates of claim 6, wherein, The barrel of the steam rotary dryer is arranged in an inclined mode, the kiln head at the right side is provided with the discharge port, the kiln tail at the left side is provided with the feeding port, steam heating pipelines are arranged in a concentric mode in the barrel, one end of the steam heating pipelines is installed on a distribution chamber at the discharge port, and the other end of the steam heating pipelines is installed on a support at the feeding port.

8. The method of claim 1-7, wherein the method is characterized by, The mixed material conveying unit comprises a bucket elevator, a transfer bin, a pneumatic conveying device and a buffer bin. The bucket elevator is used for delivering the mixed materials to a standby bin, the transfer bin is used for storing the dried mixed materials, the pneumatic conveying device is used for delivering the mixed materials to a buffer bin outside the roasting workshop, and the buffer bin is used for storing the dried mixed materials. The Z-type bucket elevator is selected, and the negative pressure conveying is adopted. The application relates to a rare earth concentrate metering and premixing unit and a method thereof. The application relates to a rare earth concentrate metering and premixing unit and a method thereof. The steam rotary dryer dries and mixes the premixed material, and the dried mixed material is discharged from a discharge port and enters the mixed material conveying unit; The mixed material is sent into the roasting kiln through the mixed material conveying unit.

9. The method for mixing, drying, and conveying rare earth concentrate as described in claim 8, characterized in that, The selected rare earth wet concentrate and the iron concentrate are respectively sent into a concentrate receiving hopper and an iron concentrate receiving hopper, weighed by a first fully-closed quantitative belt scale arranged at the lower part, and sent into the upper loading belt conveyor below at a set proportion, and the iron concentrate is weighed by a second fully-closed quantitative belt scale and sent into the upper loading belt conveyor below at a set proportion, so that the rare earth wet concentrate and the iron concentrate are premixed in the upper loading belt conveyor; the premixed material enters the steam rotary dryer from a feeding port at the kiln tail of the steam rotary dryer, and the premixed material is mixed again with the rotation of the steam rotary dryer, and the premixed material is dried by the internal steam heating pipeline, and the dried mixed material moves to the discharge port at the low part of the kiln head under the action of gravity and is discharged; the dried mixed material falls into the bucket elevator after being discharged from the discharge port, is lifted by the bucket elevator, and is conveyed to the transfer bin, and the mixed material is sent out from the discharge port at the lower part of the transfer bin according to the required amount, is aerated and loosened by the pneumatic conveying device, and is sent to the buffer bin, and the buffer bin opens the discharge port and inputs the mixed material to the feeding device below after receiving the instruction, and the feeding device conveys the mixed material to the pipe chain machine of the roasting kiln.

10. The method of claim 8, wherein the rare earth concentrate is mixed with a drying agent. The saturated steam pressure in the drying process of the premixed material is 0.5-0.8 MPaG, and the saturated steam temperature is 140-180 DEG C; the drying time of the premixed material in the steam rotary dryer is 10-30 min, and the water content of the premixed material after drying is less than 5%. ​

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