CN111235382A - Environment-friendly and energy-saving rare earth concentrate sectional roasting system and roasting method - Google Patents
Environment-friendly and energy-saving rare earth concentrate sectional roasting system and roasting method Download PDFInfo
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- CN111235382A CN111235382A CN202010100173.6A CN202010100173A CN111235382A CN 111235382 A CN111235382 A CN 111235382A CN 202010100173 A CN202010100173 A CN 202010100173A CN 111235382 A CN111235382 A CN 111235382A
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- 229910052761 rare earth metal Inorganic materials 0.000 title claims abstract description 74
- 150000002910 rare earth metals Chemical class 0.000 title claims abstract description 74
- 239000012141 concentrate Substances 0.000 title claims abstract description 58
- 238000000034 method Methods 0.000 title claims abstract description 25
- QAOWNCQODCNURD-UHFFFAOYSA-N sulfuric acid Substances OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims abstract description 65
- 238000001035 drying Methods 0.000 claims abstract description 64
- 238000001816 cooling Methods 0.000 claims abstract description 46
- 238000002156 mixing Methods 0.000 claims abstract description 45
- 239000007789 gas Substances 0.000 claims description 54
- 239000000463 material Substances 0.000 claims description 26
- 238000010438 heat treatment Methods 0.000 claims description 25
- 238000002386 leaching Methods 0.000 claims description 22
- 238000007599 discharging Methods 0.000 claims description 19
- 238000005406 washing Methods 0.000 claims description 19
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 17
- 239000000376 reactant Substances 0.000 claims description 10
- 238000000746 purification Methods 0.000 claims description 7
- 238000010521 absorption reaction Methods 0.000 claims description 6
- 239000000428 dust Substances 0.000 claims description 6
- 239000007788 liquid Substances 0.000 claims description 6
- 238000011084 recovery Methods 0.000 claims description 6
- 239000007790 solid phase Substances 0.000 claims description 6
- 239000002918 waste heat Substances 0.000 claims description 6
- 238000006243 chemical reaction Methods 0.000 claims description 5
- 239000000498 cooling water Substances 0.000 claims description 5
- IKNAJTLCCWPIQD-UHFFFAOYSA-K cerium(3+);lanthanum(3+);neodymium(3+);oxygen(2-);phosphate Chemical compound [O-2].[La+3].[Ce+3].[Nd+3].[O-]P([O-])([O-])=O IKNAJTLCCWPIQD-UHFFFAOYSA-K 0.000 claims description 4
- 229910052590 monazite Inorganic materials 0.000 claims description 4
- 239000012071 phase Substances 0.000 claims description 3
- 238000007670 refining Methods 0.000 claims description 3
- 238000004519 manufacturing process Methods 0.000 abstract description 9
- 230000007797 corrosion Effects 0.000 abstract description 3
- 238000005260 corrosion Methods 0.000 abstract description 3
- 230000007547 defect Effects 0.000 abstract description 3
- 230000007613 environmental effect Effects 0.000 abstract description 3
- 238000005272 metallurgy Methods 0.000 abstract description 2
- 238000007363 ring formation reaction Methods 0.000 abstract description 2
- RAHZWNYVWXNFOC-UHFFFAOYSA-N Sulphur dioxide Chemical compound O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 description 7
- 239000002253 acid Substances 0.000 description 6
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 6
- 238000005265 energy consumption Methods 0.000 description 5
- 239000002912 waste gas Substances 0.000 description 5
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 4
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 3
- 238000003723 Smelting Methods 0.000 description 3
- 239000011737 fluorine Substances 0.000 description 3
- 229910052731 fluorine Inorganic materials 0.000 description 3
- 239000003345 natural gas Substances 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 229910052717 sulfur Inorganic materials 0.000 description 3
- 239000011593 sulfur Substances 0.000 description 3
- 239000003513 alkali Substances 0.000 description 2
- 239000006227 byproduct Substances 0.000 description 2
- 238000001354 calcination Methods 0.000 description 2
- 238000000354 decomposition reaction Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 239000000446 fuel Substances 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 230000011218 segmentation Effects 0.000 description 2
- 239000002351 wastewater Substances 0.000 description 2
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 1
- 229910004014 SiF4 Inorganic materials 0.000 description 1
- 239000005864 Sulphur Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 125000004122 cyclic group Chemical group 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000018109 developmental process Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000003546 flue gas Substances 0.000 description 1
- 229910000040 hydrogen fluoride Inorganic materials 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000011112 process operation Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- ABTOQLMXBSRXSM-UHFFFAOYSA-N silicon tetrafluoride Chemical compound F[Si](F)(F)F ABTOQLMXBSRXSM-UHFFFAOYSA-N 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B1/00—Preliminary treatment of ores or scrap
- C22B1/02—Roasting processes
- C22B1/06—Sulfating roasting
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
- C22B59/00—Obtaining rare earth metals
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- Mechanical Engineering (AREA)
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Abstract
The invention discloses an environment-friendly and energy-saving rare earth concentrate segmented roasting system and a roasting method, which belong to the technical field of traditional metallurgy and comprise a feeding device, a drying device, a mixing device, a first-stage roasting device, a second-stage roasting device and a cooling device which are sequentially connected; the mixing device is connected with a concentrated sulfuric acid adding pipeline. The invention adopts sectional type roasting, effectively solves the defects of the traditional sulfuric acid roasting treatment process, greatly reduces the consumption of sulfuric acid, solves the problems of equipment corrosion, ring formation and blockage in a furnace and difficult tail gas treatment in the production and operation process, and has continuous and smooth whole production process, environmental protection and energy saving.
Description
Technical Field
The invention belongs to the technical field of traditional metallurgy, and particularly relates to an environment-friendly and energy-saving rare earth concentrate sectional roasting system and a roasting method.
Background
Rare earth is an important strategic resource in China, and development, smelting and the like of the rare earth resource are always important research directions. Concentrated sulfuric acid roasting has become the main production technology for smelting and processing rare earth concentrates in 80 years in 20 world, and the technology is also optimized and improved all the time, but still has many defects. The method specifically comprises the following aspects: the consumption of sulfuric acid is high, and because of the problem of the process scheme, in order to ensure the fluidity of the mixed sulfuric acid and the rare earth ore in the process of process operation, the sulfuric acid is seriously excessive in the process of mixing, and the ratio of the sulfuric acid to the rare earth concentrate in some smelting plants can reach 1.8; in addition, in the production process, the roasting furnace is easy to corrode, the furnace is easy to form rings and block, the production operation is not smooth, the furnace is frequently stopped, the roasting is not uniform, the yield is low and the quality is poor; because the fluorine-containing sulfur-containing waste gas generated in the decomposition process of the concentrate, the sulfur-containing waste gas generated after the decomposition of the sulfuric acid, the internal heating type combustion waste gas and the air are all mixed and enter a tail gas washing system, the treatment capacity of the waste gas is large, the components are very complex, the washed waste water needs to be evaporated and separated, and the operation cost and the investment cost are very high; although the concentrated sulfuric acid roasting process is researched more and is promoted continuously in recent years, the problem of high energy consumption still cannot be solved by adopting an internal heating type roasting mode; due to a plurality of uncertain and uncontrollable factors, the production operation is unstable, the product quality fluctuation is very large, and the problems of serious environmental protection and large data waste and energy consumption exist.
Therefore, the environment-friendly and energy-saving rare earth concentrate roasting process is provided to realize high product quality, stable quality, low energy consumption, high energy utilization rate and no pollution to the environment, and is a technical problem which is urgently needed to be solved in the field at present.
Disclosure of Invention
The invention provides an environment-friendly and energy-saving rare earth concentrate sectional roasting system and a roasting method, and solves the problems of high sulfuric acid consumption, high energy consumption and nonuniform roasting in the conventional rare earth concentrated sulfuric acid roasting method.
In order to solve the technical problems, the technical scheme of the invention is as follows:
an environment-friendly and energy-saving rare earth concentrate sectional roasting system comprises a feeding device, a drying device, a mixing device, a first-stage roasting device, a second-stage roasting device and a cooling device which are sequentially connected; the mixing device is connected with a concentrated sulfuric acid adding pipeline; the first-stage roasting device comprises a first-stage feeding screw, a first-stage roasting furnace and a first-stage discharging screw, the first-stage feeding screw is connected with the mixing device, and the first-stage discharging screw is connected with the second-stage roasting device; the two-stage roasting device comprises a two-stage feeding screw, a two-stage roasting furnace and a two-stage discharging screw which are sequentially connected, the two-stage feeding screw is connected with the one-stage discharging screw, and the two-stage discharging screw is connected with the cooling device.
The first-stage roasting furnace is an external heating type rotary roasting furnace, and the second-stage roasting furnace is an external heating type rotary roasting furnace.
The drying device comprises a drying feeding screw and an external heating type drying rotary furnace, the drying feeding screw is connected with the feeding device, a gas phase outlet of the external heating type drying rotary furnace is connected with a drying and dust removing system, and a solid phase outlet of the external heating type drying rotary furnace is connected with the mixing device.
Wherein, the dry dust removal system comprises a multi-stage cyclone separator and a washing tower.
Wherein, the solid phase outlet at the bottom of the multi-stage cyclone separator is spirally connected with the drying feeding, and the washing tower is also connected with a drying air blower.
The rear end part of the first-stage roasting furnace is connected with a first-stage low-temperature tail gas system, and the first-stage low-temperature tail gas system comprises a washing tower, a first-stage treatment device, a fan and a chimney which are sequentially connected.
The first-stage treatment device is an absorption tower, a refining tower or an alkaline washing tower, and the bottom of the first-stage treatment device is connected with a first cooler for material circulation treatment.
The rear end part of the second-stage roasting furnace is connected with a second-stage high-temperature tail gas system, the second-stage high-temperature tail gas system comprises a waste heat recovery device, a cooling tower and a purification tower which are sequentially connected, the bottom of the cooling tower is connected with a second cooler for material circulation treatment, the bottom of the purification tower is connected with a third cooler for material circulation treatment, and a material outlet pipe of the cooling tower is connected with a feed inlet of the purification tower through the third cooler.
The roasting method of the environment-friendly and energy-saving rare earth concentrate sectional roasting system comprises the following steps:
(1) and (3) drying: taking rare earth concentrate, adding the rare earth concentrate into a drying device through a feeding device, wherein the internal drying temperature is 120-180 ℃, the external jacket temperature of the drying device is 180-290 ℃, the drying time is 0.5-1 h, and the water content of the dried rare earth concentrate is 0.5-1 wt%;
(2) mixing materials: mixing the rare earth concentrate and high-concentration sulfuric acid in a mixing system, wherein the mass ratio of the rare earth concentrate to the high-concentration sulfuric acid is 1: 0.88-1: 1.1, the mixing time is 10-25 min, and the mixing temperature is the material temperature;
(3) first-stage roasting: the temperature of reactants in the first-stage roasting furnace is 250-300 ℃, the temperature of an external jacket of the rotary furnace is 400-600 ℃, the operating pressure in the first-stage roasting furnace is 0-100 Pa, the outlet temperature of the first-stage low-temperature tail gas is 220-260 ℃, and the first-stage roasting time is 1-3 hours;
(7) and (3) second-stage roasting: the temperature of reactants in the second-stage roasting furnace is 500-600 ℃, the operating pressure in the second-stage roasting furnace is 0-minus 10Pa, the temperature of an external jacket of the rotary furnace is 600-870 ℃, the outlet temperature of second-stage high-temperature tail gas is 450-550 ℃, and the second-stage roasting time is 1-3 hours;
(8) and (3) cooling: cooling the inside of the external heating type rotary cooling furnace to 70-80 ℃, wherein circulating cooling water or air capable of preheating a hot air system is arranged outside the rotary furnace, and the cooling time is 1.5-3 h;
(9) water leaching: roasting of ore and H at high temperature2The solid-liquid ratio of O is 1: 4-1: 8, the leaching reaction temperature is 10-50 ℃, the water leaching time is 2-8 h, and the leaching rate of the rare earth ore is more than or equal to 96%.
Wherein the rare earth concentrate is bastnaesite, monazite or a combination of the bastnaesite and the monazite, and the rare earth grade REO is more than or equal to 50 percent; the concentration of the high-concentration sulfuric acid is more than or equal to 95 wt%.
A low-temperature tail gas system is used for treating fluorine-containing tail gas, and according to different raw materials and process requirements, fluosilicic acid with the concentration of 20-40% or anhydrous hydrogen fluoride with the purity of more than or equal to 99.98% can be produced, and the waste gas can be discharged after reaching the standard through alkali washing.
The two-stage high-temperature tail gas system is used for treating sulfur-containing tail gas, the temperature of gas at the outlet of the waste heat recovery device is 180-300 ℃, the process configuration is different according to the different requirements of downstream devices, sulfuric acid with the concentration of 92-98 wt% can be adopted for washing and absorption, sulfur dioxide gas with the purity of more than or equal to 99.95 v% can be produced, or alkali washing is carried out by an electrostatic demister, and the sulfur dioxide gas reaches the standard and is discharged.
The heat energy system can be a hot air system or other heat energy systems, and the heat is recycled, for example, the hot air system is adopted, the hot air furnace enters the secondary roasting system at the temperature of about 870 ℃ at the outlet of the hot air furnace, and the hot air enters the secondary roasting system at the temperature of about 600 ℃ from the secondary roasting systemAnd (3) entering a first-stage roasting system, introducing hot air with the temperature of about 400 ℃ from the first-stage roasting system into a drying system, and discharging the hot air from the drying system after preheating the air of the hot air system. If natural gas is used as fuel of hot air system, the natural gas required by roasting treatment of each ton of rare earth is less than or equal to 83Nm3。
The invention has the beneficial effects that:
the invention adopts two-stage roasting, effectively solves the defects of the traditional sulfuric acid roasting treatment process, greatly reduces the consumption of sulfuric acid, solves the problems of corrosion of equipment and ring formation and blockage in a furnace in the production and operation process, has continuous and smooth whole production process, stable key equipment performance and long service life. Adopt external heating formula segmentation calcination, calcination tail gas unmixedly burns the gas, the tail gas volume is few composition single, and the segmentation (dry gas, fluorine-containing tail gas, sulphur-containing tail gas) produces, each section tail gas is easy to be handled and is retrieved, the by-product quality is high, the rare earth ore leaching rate is high and is more than or equal to 96%, system heat energy cyclic utilization, the efficiency utilization ratio is high, the energy consumption reduces by a wide margin, and no waste water produces, tail gas all can be up to standard discharges or send to low reaches device, and is pollution-free to the environment, belongs to novel environmental protection and energy.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.
FIG. 1 is a schematic flow diagram of an environment-friendly and energy-saving rare earth concentrate sectional roasting system in the invention.
In the figure, 1, a feeding device, 1-1, a rare earth concentrate bin, 1-2, a conveying device, 2, a drying device, 2-1, a drying feeding screw, 2-2, an external heating type drying rotary furnace, 3, a drying and dedusting system, 3-1, a multi-stage cyclone separator, 3-2, a washing tower, 3-3, a drying air fan, 4, a mixing device, 5, a first-stage roasting device, 5-1, a first-stage feeding screw, 5-2, a first-stage roasting furnace, 5-3, a first-stage discharging screw, 6, a first-stage low-temperature tail gas system, 6-1, a washing tower, 6-2, a first-stage processing device, 6-3, 6-4, a chimney, 6-5, a first-stage cooler, 7, a second-stage roasting device, 7-1, a second-stage feeding screw and 7-2, a roasting furnace, 7-3, a two-stage discharge screw, 8, a two-stage high-temperature tail gas system, 8-1, a waste heat recovery device, 8-2, a cooling tower, 8-3, a purification tower, 8-4, a second cooler, 8-5, a third cooler, 9, a cooling device, 9-1, a cooling feed screw, 9-2, an external heating type rotary cooler and 9-3, a cooling discharge screw.
Detailed Description
The technical solutions of the present invention will be described clearly and completely with reference to specific embodiments of the present invention, and it should be understood that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example 1
As shown in fig. 1, the embodiment provides an environment-friendly and energy-saving rare earth concentrate sectional roasting system, which includes a feeding device 1, a drying device 2, a mixing device, a first-stage roasting device, a second-stage roasting device and a cooling device, which are connected in sequence; the mixing device is connected with a concentrated sulfuric acid adding pipeline;
the feeding device 1 comprises a rare earth concentrate bin 1-1 and a conveying device 1-2, and belongs to a conventional solid and liquid feeding device 1; the drying device 2 comprises a drying feeding screw and an external heating type drying rotary furnace 2-2, the drying feeding screw 2-1 is connected with the feeding device 1, a gas phase outlet of the external heating type drying rotary furnace 2-2 is connected with a drying and dust removing system 3, and a solid phase outlet of the external heating type drying rotary furnace 2-2 is connected with the mixing device.
The drying and dust removing system 3 comprises a multi-stage cyclone separator 3-1 and a washing tower. The solid phase outlet at the bottom of the multi-stage cyclone separator 3-1 is connected with a drying feeding screw 2-1, and the washing tower is also connected with a drying air blower.
The mixing device is used for mixing high-concentration sulfuric acid and rare earth concentrate in the device, the mixing of the device is uniform, the corrosion problem of a section of roasting system is solved in the system, and the fluidity of the mixed sulfuric acid and rare earth concentrate can be ensured.
The first-stage roasting device comprises a first-stage feeding screw, a first-stage roasting furnace and a first-stage discharging screw, the first-stage feeding screw is connected with the mixing device, and the first-stage discharging screw is connected with the second-stage roasting device; the rear end part of the first-stage roasting furnace is connected with a first-stage low-temperature tail gas system, and the first-stage low-temperature tail gas system comprises a washing tower, a first-stage treatment device, a fan and a chimney which are sequentially connected. The first-stage treatment device is an absorption tower, a refining tower or an alkaline washing tower, and the system is configured differently according to the difference of the concentration of sulfuric acid adopted by the first-stage roasting and the requirement of downstream products. The bottom of the first section of the treatment device is connected with a first cooler for material circulation treatment. And the byproduct fluosilicic acid is sent to a downstream device, and the tail gas is absorbed and then sent to the downstream device for acid preparation.
The two-stage roasting device comprises a two-stage feeding screw, a two-stage roasting furnace and a two-stage discharging screw which are sequentially connected, the two-stage feeding screw is connected with the one-stage discharging screw, and the two-stage discharging screw is connected with the cooling device.
The back end connection of two-stage roasting furnace has two-stage high temperature tail gas system, and two-stage high temperature tail gas system is including the waste heat recovery device, cooling tower and the purifying column that connect gradually, and the second cooler that is used for material circulation to handle is connected to the cooling tower bottom, and the purifying column bottom is connected with the third cooler that is used for material circulation to handle, and the material exit tube of cooling tower is connected with the feed inlet of purifying column through the third cooler. And (4) absorbing the tail gas and then sending the tail gas to a downstream device for acid preparation.
The cooling device comprises a cooling feeding screw, an external heating type rotary cooling furnace and a cooling material screw, and the cooling material screw is connected with the water immersion system.
Wherein, a section is baked burning furnace over a slow fire for the external heating formula gyration and is baked burning furnace over a slow fire, and a section is baked burning furnace over a slow fire and is included the furnace body, and the outside of furnace body is equipped with the cover that presss from both sides, and both ends are connected with feed arrangement and discharging device respectively around the furnace body, and feed arrangement and discharging device all are equipped with sealing device with the junction of furnace body, and the preceding tip of furnace body is equipped with preceding riding wheel mechanism, and the rear end.
The two-stage roasting furnace is an external heating type rotary roasting furnace and comprises a furnace body, a jacket and a main transmission mechanism are arranged outside the furnace body, the front end of the furnace body is connected with a feeding device, the rear end of the furnace body is connected with a discharge screw, a front riding wheel mechanism is arranged at the front end of the furnace body, and a rear riding wheel mechanism is arranged at the rear end of the furnace body.
In this embodiment, the heat energy system uses a hot air system, natural gas is used as fuel, and provides hot flue gas to an external heat drying rotary furnace, an external heat type rotary first-stage roasting furnace, and an external heat type rotary second-stage roasting furnace.
Example 2
The method for roasting the rare earth concentrate by adopting the roasting system in the embodiment 1 comprises the following steps:
(1) the rare earth concentrate is prepared from the following raw materials in a weight ratio of 1:1, the rare earth grade REO is not less than 55 percent.
(2) Concentrated sulfuric acid with a concentration of 98 wt% is used.
(3) The mass ratio of the rare earth concentrate to the high-concentration sulfuric acid is 1: 0.88.
(4) A drying device: the internal drying temperature is 150 ℃, the hot air temperature of an external jacket of the converter is 180-290 ℃, the drying time is 1h, and the water content of the dried rare earth concentrate is 0.8 wt%.
(5) The material mixing device comprises: and mixing the rare earth concentrate and concentrated sulfuric acid in a mixing system, wherein the mass ratio of the rare earth concentrate to the high-concentration sulfuric acid is 1:0.88, the mixing time in a self-cleaning mixing device is 15min, and the mixing temperature is the material temperature.
(6) A first stage roasting device: the temperature of reactants in the externally heated rotary first-stage roasting furnace is 290 ℃, the temperature of an external jacket of the rotary furnace is 500 ℃, the operating pressure in the first-stage roasting furnace is-80 Pa, the outlet temperature of first-stage low-temperature tail gas is 250 ℃, and the first-stage roasting time is 2 hours.
(7) In the second-stage roasting device, the temperature of reactants in an externally heated rotary second-stage roasting furnace is 580 ℃, the operating pressure in the second-stage roasting furnace is-5 Pa, the temperature of an external jacket of the rotary furnace is 750 ℃, the outlet temperature of second-stage high-temperature tail gas is 530 ℃, and the second-stage roasting time is 1.5 h.
(8) And in the cooling device, the external heating type rotary cooling furnace is cooled to 75 ℃, circulating cooling water is introduced into a jacket of the rotary furnace to serve as a cold source, and the cooling time is 2 hours.
(9) A first-stage low-temperature tail gas absorption system: treating tail gas containing HF and SiF4, producing fluorosilicic acid solution with concentration of 35% according to the requirement of downstream equipment, and washing the tail gas before sending to downstream acid-making equipment.
(10) Two-stage high-temperature tail gas absorption system: treatment of gases containing SO2The temperature of the tail gas at the outlet of the waste heat recovery device is 300 ℃, the tail gas can be washed and absorbed by sulfuric acid with the concentration of 92 wt% according to the requirements of downstream devices, and the produced sulfur dioxide gas with the purity of 99.95 v% is sent to the downstream acid production devices.
(11) The roasted rare earth ore discharged from the rotary cooling furnace of the cooling system enters a water leaching system, and the roasted ore and H enter a water leaching system2The solid-liquid ratio of O is 1:6, the leaching reaction temperature is 40 ℃, the water leaching time is 6 hours, and the leaching rate of the rare earth ore is 96.5 percent.
Example 3
The method for roasting the rare earth concentrate by adopting the roasting system in the embodiment 1 comprises the following steps:
(1) the rare earth concentrate adopts bastnaesite, and the rare earth grade REO is not less than 55%.
(2) Concentrated sulfuric acid with a concentration of 98 wt% is used.
(3) The mass ratio of the rare earth concentrate to the high-concentration sulfuric acid is 1: 1.1.
(4) And (3) drying: taking rare earth concentrate, adding the rare earth concentrate into a drying device through a feeding device, wherein the internal drying temperature is 120 ℃, the external jacket temperature of the drying device is 180-290 ℃, the drying time is 0.5h, and the water content of the dried rare earth concentrate is 0.5 wt%;
(5) mixing materials: mixing the rare earth concentrate and high-concentration sulfuric acid in a mixing system, wherein the mixing time is 10min, and the mixing temperature is the material temperature;
(6) first-stage roasting: the temperature of reactants in the first-stage roasting furnace is 250 ℃, the temperature of an external jacket of the rotary furnace is 600 ℃, the operating pressure in the first-stage roasting furnace is 0Pa, the outlet temperature of the first-stage low-temperature tail gas is 260 ℃, and the first-stage roasting time is 1 h;
(7) and (3) second-stage roasting: the temperature of reactants in the second-stage roasting furnace is 500 ℃, the operating pressure in the second-stage roasting furnace is-10 Pa, the temperature of an external jacket of the rotary furnace is 600 ℃, the outlet temperature of the second-stage high-temperature tail gas is 550 ℃, and the second-stage roasting time is 1 h;
(8) and (3) cooling: cooling the inside of the external heating type rotary cooling furnace to 70 ℃, wherein circulating cooling water or air capable of preheating a hot air system is arranged outside the rotary furnace, and the cooling time is 1.5-3 h;
(9) water leaching: roasting of ore and H at high temperature2The solid-liquid ratio of O is 1:4, the leaching reaction temperature is 50 ℃, the water leaching time is 2h, and the leaching rate of the rare earth ore is 97%.
Example 4
The method for roasting the rare earth concentrate by adopting the roasting system in the embodiment 1 comprises the following steps:
(1) the rare earth concentrate adopts bastnaesite, and the rare earth grade REO is not less than 55%.
(2) Concentrated sulfuric acid with a concentration of 95 wt% was used.
(3) The mass ratio of the rare earth concentrate to the high-concentration sulfuric acid is 1: 1.05.
(4) And (3) drying: taking rare earth concentrate, adding the rare earth concentrate into a drying device through a feeding device, wherein the internal drying temperature is 180 ℃, the external jacket temperature of the drying device is 180-290 ℃, the drying time is 1h, and the water content of the dried rare earth concentrate is 1 wt%;
(5) mixing materials: mixing the rare earth concentrate and high-concentration sulfuric acid in a mixing system, wherein the mixing time is 25min, and the mixing temperature is the material temperature;
(6) first-stage roasting: the temperature of reactants in the first-stage roasting furnace is 300 ℃, the temperature of an external jacket of the rotary furnace is 400 ℃, the operating pressure in the first-stage roasting furnace is-100 Pa, the outlet temperature of the first-stage low-temperature tail gas is 220-DEG C, and the first-stage roasting time is 3 hours;
(7) and (3) second-stage roasting: the temperature of reactants in the second-stage roasting furnace is 600 ℃, the operating pressure in the second-stage roasting furnace is 0Pa, the temperature of an external jacket of the rotary furnace is 870 ℃, the outlet temperature of second-stage high-temperature tail gas is 450 ℃, and the second-stage roasting time is 3 hours;
(8) and (3) cooling: cooling the inside of the external heating type rotary cooling furnace to 80 ℃, wherein circulating cooling water or air capable of preheating a hot air system is arranged outside the rotary furnace, and the cooling time is 1.5-3 h;
(9) water leaching: roasting of ore and H at high temperature2The solid-liquid ratio of O is 1:8, the leaching reaction temperature is 10 ℃, the water leaching time is 8 hours, and the leaching rate of the rare earth ore is 96%.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (9)
1. An environment-friendly and energy-saving rare earth concentrate sectional roasting system is characterized by comprising a feeding device, a drying device, a mixing device, a first-stage roasting device, a second-stage roasting device and a cooling device which are sequentially connected; the mixing device is connected with a concentrated sulfuric acid adding pipeline; the first-stage roasting device comprises a first-stage feeding screw, a first-stage roasting furnace and a first-stage discharging screw, the first-stage feeding screw is connected with the mixing device, and the first-stage discharging screw is connected with the second-stage roasting device; the two-stage roasting device comprises a two-stage feeding screw, a two-stage roasting furnace and a two-stage discharging screw which are sequentially connected, the two-stage feeding screw is connected with the one-stage discharging screw, and the two-stage discharging screw is connected with the cooling device.
2. The environment-friendly and energy-saving rare earth concentrate sectional roasting system of claim 1, characterized in that: the first-stage roasting furnace and the second-stage roasting furnace are external heating type rotary roasting furnaces.
3. The environment-friendly and energy-saving rare earth concentrate sectional roasting system of claim 1, characterized in that: the drying device comprises a drying feeding screw and an external heating type drying rotary furnace, the drying feeding screw is connected with the feeding device, a gas phase outlet of the external heating type drying rotary furnace is connected with a drying and dust removing system, and a solid phase outlet of the external heating type drying rotary furnace is connected with the material mixing device.
4. The environment-friendly and energy-saving rare earth concentrate sectional roasting system of claim 3, wherein the roasting system comprises: the drying and dust removing system comprises a multi-stage cyclone separator and a washing tower; and a solid phase outlet at the bottom of the multi-stage cyclone separator is spirally connected with the drying feeding material, and the washing tower is also connected with a drying air blower.
5. The environment-friendly and energy-saving rare earth concentrate sectional roasting system of claim 1, characterized in that: the rear end part of the first-stage roasting furnace is connected with a first-stage low-temperature tail gas system, and the first-stage low-temperature tail gas system comprises a washing tower, a first-stage treatment device, a fan and a chimney which are sequentially connected.
6. The environment-friendly and energy-saving rare earth concentrate sectional roasting system of claim 5, wherein: the first-stage treatment device is an absorption tower, a refining tower or an alkaline washing tower, and the bottom of the first-stage treatment device is connected with a first cooler for material circulating treatment.
7. The environment-friendly and energy-saving rare earth concentrate sectional roasting system of claim 1, characterized in that: the rear end part of the second-stage roasting furnace is connected with a second-stage high-temperature tail gas system, the second-stage high-temperature tail gas system comprises a waste heat recovery device, a cooling tower and a purification tower which are sequentially connected, the bottom of the cooling tower is connected with a second cooler for material circulation treatment, the bottom of the purification tower is connected with a third cooler for material circulation treatment, and a material outlet pipe of the cooling tower is connected with a feed inlet of the purification tower through the third cooler.
8. The roasting method of the environment-friendly and energy-saving rare earth concentrate sectional roasting system is characterized by comprising the following steps of:
(1) and (3) drying: taking rare earth concentrate, adding the rare earth concentrate into a drying device through a feeding device, wherein the internal drying temperature is 120-180 ℃, the external jacket temperature of the drying device is 180-290 ℃, the drying time is 0.5-1 h, and the water content of the dried rare earth concentrate is 0.5-1 wt%;
(2) mixing materials: mixing the rare earth concentrate and high-concentration sulfuric acid in a mixing system, wherein the mass ratio of the rare earth concentrate to the high-concentration sulfuric acid is 1: 0.88-1: 1.1, the mixing time is 10-25 min, and the mixing temperature is the material temperature;
(3) first-stage roasting: the temperature of reactants in the first-stage roasting furnace is 250-300 ℃, the temperature of an external jacket of the rotary furnace is 400-600 ℃, the operating pressure in the first-stage roasting furnace is 0-100 Pa, the outlet temperature of the first-stage low-temperature tail gas is 220-260 ℃, and the first-stage roasting time is 1-3 hours;
(7) and (3) second-stage roasting: the temperature of reactants in the second-stage roasting furnace is 500-600 ℃, the operating pressure in the second-stage roasting furnace is 0-minus 10Pa, the temperature of an external jacket of the rotary furnace is 600-870 ℃, the outlet temperature of second-stage high-temperature tail gas is 450-550 ℃, and the second-stage roasting time is 1-3 hours;
(8) and (3) cooling: cooling the inside of the external heating type rotary cooling furnace to 70-80 ℃, wherein circulating cooling water or air capable of preheating a hot air system is arranged outside the rotary furnace, and the cooling time is 1.5-3 h;
(9) water leaching: roasting of ore and H at high temperature2The solid-liquid ratio of O is 1: 4-1: 8, the leaching reaction temperature is 10-50 ℃, the water leaching time is 2-8 h, and the leaching rate of the rare earth ore is more than or equal to 96%.
9. The roasting method of the environment-friendly and energy-saving rare earth concentrate sectional roasting system of claim 8, characterized in that: the rare earth concentrate is bastnaesite, monazite or a combination of the bastnaesite and the monazite, and the rare earth grade REO is more than or equal to 50 percent; the concentration of the high-concentration sulfuric acid is more than or equal to 95 wt%.
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| CN115449624A (en) * | 2022-08-11 | 2022-12-09 | 甘肃稀土新材料股份有限公司 | Method for treating high-iron low-phosphorus rare earth ore |
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