阅读说明：本技术 稀土精矿浓硫酸法焙烧烟气的干湿法结合处理系统 (Dry-wet combined treatment system for roasting flue gas by rare earth concentrate concentrated sulfuric acid method ) 是由 李博 魏小林 于 2019-09-10 设计创作，主要内容包括：本发明实施例涉及一种稀土精矿浓硫酸法焙烧烟气的干湿法结合处理系统,包括：粗除尘设备、余热锅炉、酸回收设备和湿法除氟除尘设备；粗除尘设备的输入端与外部的烟气管道连接,粗除尘设备的第一输出端与余热锅炉的输入端连接；余热锅炉的第一输出端与湿法除氟除尘设备连接,余热锅炉的第二输出端与酸回收设备连接；采用干湿法相结合的烟气处理技术,在高温段利用烟气-水换热蒸发原理回收烟气余热,替换现有喷淋塔在高温段直接水洗技术,集烟气降温、除尘、脱酸,高浓度氟酸和硫酸回收为一体,相比原工艺设备,设备更加简单、工艺流程缩短降低了低浓度酸处理和污水处理等的固定投资成本、能耗相对降低、功能更加集中,同时减少了后期污水的处理量。(the embodiment of the invention relates to a dry-wet combined treatment system for rare earth concentrate concentrated sulfuric acid roasting flue gas, which comprises: the system comprises a coarse dust removal device, a waste heat boiler, an acid recovery device and a wet-method fluorine and dust removal device; the input end of the coarse dust removal equipment is connected with an external flue gas pipeline, and the first output end of the coarse dust removal equipment is connected with the input end of the waste heat boiler; the first output end of the waste heat boiler is connected with the wet-method fluorine and dust removal equipment, and the second output end of the waste heat boiler is connected with the acid recovery equipment; the flue gas treatment technology combining the dry method and the wet method is adopted, the flue gas waste heat is recovered by utilizing the flue gas-water heat exchange evaporation principle in a high-temperature section, the existing spray tower is replaced by the direct water washing technology in the high-temperature section, the flue gas cooling, dust removal and deacidification are integrated, and the high-concentration fluoric acid and the sulfuric acid are recovered into a whole.)

1. A dry-wet combined treatment system for rare earth concentrate concentrated sulfuric acid roasting flue gas is characterized by comprising the following steps:

The system comprises a coarse dust removal device, a waste heat boiler, an acid recovery device and a wet-method fluorine and dust removal device;

the input end of the coarse dust removal equipment is connected with an external flue gas pipeline, and the first output end of the coarse dust removal equipment is connected with the input end of the waste heat boiler; the first output end of the waste heat boiler is connected with the wet-method fluorine and dust removal equipment, and the second output end of the waste heat boiler is connected with the acid recovery equipment.

2. The processing system of claim 1, wherein the coarse dust removal device comprises: a coarse dust removal device and a slag recovery device;

the input end of the coarse dust removal device is connected with an external flue gas pipeline, the first output end of the coarse dust removal device is connected with the input end of the waste heat boiler, and the second output end of the coarse dust removal device is connected with the slag recovery device;

The coarse dust removal device removes dust through high-efficiency inertia, the rare earth concentrate concentrated sulfuric acid high-temperature roasting tail gas at the speed of 13-18 m/s is impacted on the baffle, the flow direction of flue gas is changed rapidly, and dust is separated from air flow by means of the action of inertia force of dust particles.

3. the treatment system of claim 1, wherein the acid recovery apparatus comprises: a sulfuric acid recovery device and a hydrofluoric acid recovery device;

the second output end of the waste heat boiler is respectively connected with the sulfuric acid recovery device and the hydrofluoric acid recovery device;

the method comprises the steps of regulating and controlling the outlet temperature of the multistage heat exchange equipment of the waste heat boiler, carrying out fractional recovery on fluoric acid by a sulfuric acid recovery device through dry condensation, and carrying out fractional recovery on the sulfuric acid by the fluoric acid recovery device.

4. The processing system of claim 1, wherein the wet defluorination dust removal device comprises:

A wet-method fluorine and dust removal device and a fine dust removal device which are connected in sequence;

The wet-method fluorine and dust removal device removes dust by spraying fluorine and sprays water by means of a spray tower to enable the flue gas to be in contact with the spray water so that fluoride in the flue gas is dissolved in the water.

5. the treatment system of claim 3, wherein the waste heat boiler is connected with the acid recovery device through a multistage heat exchange device through a high temperature resistant glass fiber reinforced plastic pipeline.

6. The treatment system of claim 4, wherein the conduit is an elbow.

7. The treatment system according to any one of claims 1 to 6, wherein the waste heat boiler comprises: flue gas-water heat transfer equipment.

8. the treatment system of claim 7, wherein the flue gas-water heat exchange device is internally provided with a temperature-resistant and wear-resistant corrosion-resistant inner coating.

9. the processing system of claim 1, further comprising: a desulfurizing tower;

And the output end of the wet-method fluorine and dust removing equipment is connected with the input end of the desulfurizing tower.

10. The processing system of claim 9, further comprising: a chimney;

And the output end of the desulfurizing tower is connected with the chimney.

Technical Field

The embodiment of the invention relates to the field of flue gas treatment, in particular to a dry-wet combined treatment system for rare earth concentrate roasting flue gas by a concentrated sulfuric acid method.

Background

At present, the smelting of rare earth concentrate is mainly carried out in a single-stage rotary roasting kiln with the inner diameter of 1.5-2.2 m and the length of 25-35 m by adopting a three-acid-method high-temperature roasting production process, wherein natural gas is combusted at the head of the kiln to enable the temperature of the head of the kiln to reach 600-800 ℃, and the temperature of smoke gas at the tail of the kiln to reach 300 ℃. The process inevitably produces a large amount of high-temperature strong-acid tail gas containing hydrogen fluoride, sulfur dioxide and sulfuric acid, and the prior art generally adopts the processes of cooling, dedusting and recycling mixed acid by water spraying flue gas to treat the tail gas, and the technical key points of the process mainly comprise the following points: 1. a multi-stage circulating dedusting, cooling and deacidifying spray tower is adopted; 2. the acid water in the spray tower is cooled through multi-stage heat exchange, and a cold source is circulating cooling water; 3. the mixed acid is separated by adopting a steam heating mode, and then the hydrofluoric acid and the sulfuric acid are recycled by cooling circulating water condensation.

However, the spraying process of the process not only consumes a large amount of cooling water, but also the recovered waste acid solution is low-concentration mixed acid, and can be recovered and reused by adopting further concentration and separation process treatment through an evaporator and a condenser (triple effect evaporation), and a large amount of waste heat resources carried by high-temperature flue gas are wasted, so that the problems of high energy consumption, complex process, long treatment time, water resource waste and the like exist.

Disclosure of Invention

In view of this, in order to solve the above technical problems or some technical problems, embodiments of the present invention provide a dry-wet combined treatment system for rare earth concentrate roasting flue gas by concentrated sulfuric acid.

In a first aspect, an embodiment of the present invention provides a dry-wet method combined processing system for rare earth concentrate concentrated sulfuric acid roasting flue gas, including:

The system comprises a coarse dust removal device, a waste heat boiler, an acid recovery device and a wet-method fluorine and dust removal device;

the input end of the coarse dust removal equipment is connected with an external flue gas pipeline, and the first output end of the coarse dust removal equipment is connected with the input end of the waste heat boiler; the first output end of the waste heat boiler is connected with the wet-method fluorine and dust removal equipment, and the second output end of the waste heat boiler is connected with the acid recovery equipment.

In one possible embodiment, the coarse dust removal apparatus includes: a coarse dust removal device and a slag recovery device;

The input end of the coarse dust removal device is connected with an external flue gas pipeline, the first output end of the coarse dust removal device is connected with the input end of the waste heat boiler, and the second output end of the coarse dust removal device is connected with the slag recovery device;

The coarse dust removal device removes dust through high-efficiency inertia, the rare earth concentrate concentrated sulfuric acid high-temperature roasting tail gas at the speed of 13-18 m/s is impacted on the baffle, the flow direction of flue gas is changed rapidly, and dust is separated from air flow by means of the action of inertia force of dust particles.

In one possible embodiment, the acid recovery apparatus comprises: a sulfuric acid recovery device and a hydrofluoric acid recovery device;

The second output end of the waste heat boiler is respectively connected with the sulfuric acid recovery device and the hydrofluoric acid recovery device;

The method comprises the steps of regulating and controlling the outlet temperature of the multistage heat exchange equipment of the waste heat boiler, carrying out fractional recovery on fluoric acid by a sulfuric acid recovery device through dry condensation, and carrying out fractional recovery on the sulfuric acid by the fluoric acid recovery device.

in one possible embodiment, the wet-method fluorine and dust removing device comprises:

A wet-method fluorine and dust removal device and a fine dust removal device which are connected in sequence;

the wet-method fluorine and dust removal device removes dust by spraying fluorine and sprays water by means of a spray tower to enable the flue gas to be in contact with the spray water so that fluoride in the flue gas is dissolved in the water.

In one possible embodiment, the waste heat boiler is connected with the acid recovery device through a multistage heat exchange device and a high-temperature-resistant glass fiber reinforced plastic pipeline.

in one possible embodiment, the conduit is an elbow.

In one possible embodiment, the waste heat boiler comprises: flue gas-water heat transfer equipment.

in one possible embodiment, the flue gas-water heat exchange equipment is internally provided with a temperature-resistant and wear-resistant corrosion-resistant inner coating.

In one possible embodiment, the processing system further comprises: a desulfurizing tower;

and the output end of the wet-method fluorine and dust removing equipment is connected with the input end of the desulfurizing tower.

In one possible embodiment, the processing system further comprises: a chimney;

and the output end of the desulfurizing tower is connected with the chimney.

the dry-wet combined treatment system for roasting flue gas by the rare earth concentrate concentrated sulfuric acid method provided by the embodiment of the invention adopts a dry-wet combined flue gas treatment technology, recovers flue gas waste heat by utilizing a flue gas-water heat exchange evaporation principle in a high-temperature section, replaces the existing spray tower to directly wash water in the high-temperature section, integrates flue gas cooling, dust removal and deacidification, and recovers high-concentration fluoric acid and sulfuric acid into a whole; a large amount of waste heat of high-temperature flue gas is effectively utilized to realize the byproduct steam of the high-temperature roasting process of rare earth concentrate concentrated sulfuric acid; the two-stage dust removal technology is adopted to carry out coarse dust removal and fine dust removal on the flue gas in sequence, so that the dust removal efficiency is high; high-concentration acid recovery is realized by cooling and condensing, the recovery concentration of sulfuric acid can reach 65%, and the recovery concentration of fluoric acid can reach 14%. Compared with the original process, the smelting production line capable of processing the concentrate in 10800 tons per year can save 0.64 ton of steam for acid distillation per hour; the wet defluorination and dust removal technology is adopted, the defluorination and dust removal efficiency is high, and the equipment is simple.

Drawings

FIG. 1 is a schematic structural diagram of a dry-wet combined treatment system for rare earth concentrate concentrated sulfuric acid roasting flue gas provided by an embodiment of the invention;

Fig. 2 is a schematic structural diagram of another dry-wet combined treatment system for roasting flue gas by a rare earth concentrate concentrated sulfuric acid method according to an embodiment of the invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. 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.

For the convenience of understanding of the embodiments of the present invention, the following description will be further explained with reference to specific embodiments, which are not to be construed as limiting the embodiments of the present invention.

FIG. 1 is a schematic structural diagram of a dry-wet combined treatment system for rare earth concentrate concentrated sulfuric acid roasting flue gas provided by an embodiment of the invention;

the system comprises a coarse dust removal device, a waste heat boiler, an acid recovery device and a wet-method fluorine and dust removal device;

the input end of the coarse dust removal equipment is connected with an external flue gas pipeline, and the first output end of the coarse dust removal equipment is connected with the input end of the waste heat boiler; the first output end of the waste heat boiler is connected with the wet-method fluorine and dust removal equipment, and the second output end of the waste heat boiler is connected with the acid recovery equipment.

Further, the coarse dust removing apparatus includes: a coarse dust removal device and a slag recovery device;

The input end of the coarse dust removal device is connected with an external flue gas pipeline, the first output end of the coarse dust removal device is connected with the input end of the waste heat boiler, and the second output end of the coarse dust removal device is connected with the slag recovery device;

the coarse dust removal device removes dust through high-efficiency inertia, the rare earth concentrate concentrated sulfuric acid high-temperature roasting tail gas at the speed of 13-18 m/s is impacted on the baffle, the flow direction of flue gas is changed rapidly, and dust is separated from air flow by means of the action of inertia force of dust particles.

Specifically, referring to fig. 2, the coarse dust removal device 1 is a first process after the high-temperature flue gas at the kiln tail is led out, and performs coarse dust removal on the high-temperature flue gas to primarily remove a large amount of dust in the high-temperature flue gas, so as to reduce damage of the large amount of dust in the flue gas to subsequent equipment. The device adopts high-efficient inertial dust removal technology, and the velocity of flow is in the impact of the rare earth concentrate concentrated sulfuric acid high temperature calcination tail gas of 13 ~ 18 ms on the baffle, and the flue gas flow direction takes place sharp transition, makes its and air current separation with the help of the inertial force effect of dust particle itself, can realize the dust collection efficiency more than 95%, and the dust particle enters into sediment recovery unit 4 along the cone under coarse dust collector 1.

further, the waste heat boiler is connected with the acid recovery device through a multistage heat exchange device through a high-temperature-resistant glass fiber reinforced plastic pipeline.

Further, the pipeline is an elbow.

Further, the waste heat boiler comprises: flue gas-water heat transfer equipment.

Furthermore, a temperature-resistant and wear-resistant corrosion-resistant inner coating is arranged inside the flue gas-water heat exchange equipment.

Specifically, referring to fig. 2, the exhaust-heat boiler 2 serves as a core device of the system and performs a function of recycling the exhaust heat of the high-temperature flue gas. The waste heat boiler 2 adopts a flue gas-water heat exchange technology and consists of a plurality of stages of flue gas-water heat exchange equipment. The interior of the inner layer adopts a temperature-resistant, wear-resistant and corrosion-resistant inner coating.

The high-temperature flue gas passing through the coarse dust removal device 1 is introduced into the waste heat boiler 2, the high-temperature flue gas is cooled through a waste heat recovery device in the waste heat boiler, and meanwhile, the recovered waste heat is used for carrying out flash evaporation on water to generate steam, so that the waste heat can be utilized to the maximum benefit. After the high-temperature flue gas passes through the waste heat boiler, the temperature is reduced from 300 ℃ to about 60 ℃, a large amount of waste heat is recovered to generate steam, and the steam is recovered through a steam pipeline.

further, the acid recovery apparatus includes: a sulfuric acid recovery device 5 and a hydrofluoric acid recovery device 6;

The second output end of the waste heat boiler 2 is respectively connected with the sulfuric acid recovery device 5 and the hydrofluoric acid recovery device 6;

The method comprises the steps of regulating and controlling the outlet temperature of the multistage heat exchange equipment of the waste heat boiler, carrying out fractional recovery on fluoric acid by a sulfuric acid recovery device through dry condensation, and carrying out fractional recovery on the sulfuric acid by the fluoric acid recovery device.

specifically, the flue gas is cooled by the waste heat boiler, simultaneously the latent heat released by the acid gas is condensed into a liquid state to form mixed acid, and the mixed acid is collected and processed by the acid recovery system and then is sent to the feed opening for cyclic utilization. The process adopts a dry acid recovery technology, regulates and controls the temperature through a waste heat boiler according to different acid condensation modes and different condensation temperatures, condenses and recovers sulfuric acid and fluoric acid in stages, and the recovery rate reaches 90%. Due to the adoption of dry condensation, the recovery concentration of the fluoric acid is as high as 14 percent, and the recovery concentration of the sulfuric acid is as high as 65 percent.

further, the wet-method fluorine and dust removing device 3 comprises:

A wet-method fluorine and dust removal device (not shown in FIG. 2) and a fine dust removal device (not shown in FIG. 2) which are connected in sequence;

the wet-method fluorine and dust removal device removes dust by spraying fluorine and sprays water by means of a spray tower to enable the flue gas to be in contact with the spray water so that fluoride in the flue gas is dissolved in the water.

specifically, the main equipment of the wet-method defluorination and dust removal equipment adopts a spraying defluorination and dust removal technology, spray water is sprayed into the tower from the top of a spray tower, flue gas is in reverse contact with the spray water from bottom to top, the contact area is increased, and residual fluoride and dust particles in the flue gas can be removed. Fluoride in the smoke can be reduced to 20mg/Nm³The dust content is less than 10mg/Nm³。

Further, the processing system further comprises: a desulfurizing tower 7;

And the output end of the wet-method fluorine and dust removing equipment is connected with the input end of the desulfurizing tower.

further, the processing system further comprises: a chimney 8;

And the output end of the desulfurizing tower is connected with the chimney.

The dry-wet combined treatment system for roasting flue gas by the rare earth concentrate concentrated sulfuric acid method provided by the embodiment of the invention adopts a dry-wet combined flue gas treatment technology, recovers flue gas waste heat by utilizing a flue gas-water heat exchange evaporation principle in a high-temperature section, replaces the existing spray tower to directly wash water in the high-temperature section, integrates flue gas cooling, dust removal and deacidification, and recovers high-concentration fluoric acid and sulfuric acid into a whole; a large amount of waste heat of high-temperature flue gas is effectively utilized to realize the byproduct steam of the high-temperature roasting process of rare earth concentrate concentrated sulfuric acid; the two-stage dust removal technology is adopted to carry out coarse dust removal and fine dust removal on the flue gas in sequence, so that the dust removal efficiency is high; high-concentration acid recovery is realized by cooling and condensing, the recovery concentration of sulfuric acid can reach 65%, and the recovery concentration of fluoric acid can reach 14%. Compared with the original process, the smelting production line capable of processing the concentrate in 10800 tons per year can save 0.64 ton of steam for acid distillation per hour; the wet defluorination and dust removal technology is adopted, the defluorination and dust removal efficiency is high, and the equipment is simple.

Those of skill would further appreciate that the various illustrative components and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both, and that the various illustrative components and steps have been described above generally in terms of their functionality in order to clearly illustrate this interchangeability of hardware and software. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

the above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are merely exemplary embodiments of the present invention, and are not intended to limit the scope of the present invention, and any modifications, equivalent substitutions, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.