A lithium battery waste liquid resource environmental protection treatment system and process flow

Abstract

The invention discloses a lithium battery waste liquid resource environmental protection treatment system and process flow, which relates to the technical field of industrial waste environmental protection treatment and resource utilization, including an incinerator, a semi-dry deacidification reactor, a quenching tower, a primary deacidification tower, a secondary deacidification tower, a flue gas heat exchanger, a dust collector, a flue gas heater, a denitration device, a chimney, and a slag liquid collection tank, a waste liquid treatment tank, a waste solid salt solution adding hydrochloric acid treatment tank, a waste solid salt solution adding LiOH treatment tank, a rotary drum, an evaporator, a drying furnace and other main equipment, and Na in the lithium battery waste liquid is converted into Na by using combustion and chemical reaction technologies. + , Ca 2+ 、F ‑ , Cl ‑ , Li + The invention fully realizes the purpose of harmless, reduced and resourceful treatment of lithium battery waste liquid. It has outstanding environmental protection effect, full resource utilization and obvious energy saving and consumption reduction effect. The overall design of the system and equipment is reasonable, the structure is compact, the treatment method is flexible and adaptable, and it is suitable for promotion and use.

Description

Technical Field

[0001] The present invention relates to the technical field of industrial waste treatment and recycling, and in particular to a lithium battery waste liquid resource recovery and environmental protection treatment system and process flow. Background Art

[0002] Today's chemical industry is becoming more and more developed, the amount of waste liquid and waste gas generated is increasing, and the country's requirements for environmental protection are also getting higher and higher. With the development of production, chemical production equipment is being built rapidly on a large scale, and the output of hazardous waste is increasing.

[0003] For example, lithium batteries are one of the most popular batteries in the 21st century, and are widely used in cameras, mobile phones, laptops, portable measuring instruments, electric vehicles, etc. With the policy promotion of oil-free vehicles, the use of lithium batteries will increase, and there will be more and more lithium battery production plants. Similarly, the waste liquid generated by the production of lithium batteries is also increasing. During the production process of lithium batteries, a large amount of cleaning wastewater will be generated. The cleaning wastewater contains a large amount of organic pollutants and is highly toxic. It is a hazardous waste and cannot be discharged directly. It needs to be treated before it can be discharged. Therefore, the treatment process of lithium battery waste liquid has also come into being. The existing technology generally uses electrochemical flocculation precipitation for treatment.

[0004] For example, Patent No. CN201610057373.1 is a method for treating waste lithium battery electrolyte and electrolyte wastewater based on MBR and A2 / O, and Patent No. CN201710015803.8 is a process for treating lithium battery waste liquid and its treatment system. Both use electrochemical methods for treatment, which have high process requirements, long reaction time, low efficiency, and high requirements for operators. The final waste is not well utilized, which wastes precious Li resources and still requires special treatment later.

[0005] The country has higher and higher requirements for the treatment technology of hazardous waste. Incineration technology has become an important technology in the chemical industry with its advantages of thorough treatment, high efficiency, low investment and small land occupation. Incineration equipment has also become an important part of chemical equipment. Incineration method for treating organic waste is an effective means of treating organic matter in waste liquid by deep oxidation of air under high temperature conditions. Usually, organic compound waste is incinerated at high temperature, converted into CO2 and H2O, and then discharged into the atmosphere. As long as the temperature in the incinerator is greater than 1100℃ and the waste has a long enough residence time in the high temperature zone of the furnace, the waste can basically be completely decomposed. After dust removal, deacidification, denitrification and other flue gas purification treatment methods, environmental protection standards or ultra-clean emissions can be achieved. At the same time, the use of advanced technology to recycle useful components in the waste during the incineration process can realize the resource utilization of waste.

[0006] Therefore, how to achieve standard discharge of waste and use the waste reasonably to kill two birds with one stone is an important issue facing engineering designers and is also the main purpose of this patent. Summary of the invention

[0007] The purpose of the present invention is to provide a lithium battery waste liquid resource recovery and environmental protection treatment system to solve the problems raised in the above background technology.

[0008] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a lithium battery waste liquid resource environmental protection treatment system, including an incinerator, a semi-dry deacidification reactor, a primary deacidification tower, a secondary deacidification tower, a flue gas heat exchanger, a bag filter, a denitrification device, a chimney, a drying furnace and an evaporator, the waste liquid atomizing spray gun arranged on the wall of the incinerator is connected to a waste liquid storage tank and two screw delivery pumps, one for backup and the other for use, an auxiliary fuel burner is arranged on the wall of the incinerator, and the flue gas outlet of the incinerator is connected to the waste liquid storage tank and the two screw delivery pumps, one for backup and the other for use, through a pipeline, The flue is connected in sequence with a semi-dry deacidification reactor, a quenching water tower, a primary deacidification tower, a secondary deacidification tower, a flue gas heat exchanger, a bag filter, a denitration device and a chimney. The flue gas outlet of the denitration device is connected to the flue gas inlet of the flue gas heat exchanger. The flue gas outlet of the flue gas heat exchanger is provided with an induced draft fan connected to the lower end of the chimney. The lower side of the incinerator is connected in sequence with a slag liquid collection tank and a waste liquid treatment tank through a pipeline. The waste liquid treatment tank is connected in sequence with a waste liquid delivery pump, a rotary drum A, and a waste solid salt through a pipeline. The dissolving liquid is added with hydrochloric acid treatment tank, and the waste solid salt dissolving liquid is added with hydrochloric acid treatment tank, and then a standby waste solid salt dissolving liquid primary delivery pump is connected to the waste solid salt dissolving liquid adding LiOH treatment tank through a pipeline, and the waste solid salt dissolving liquid adding LiOH treatment tank is sequentially connected with the waste solid salt dissolving liquid secondary delivery pump, drum B, evaporator, and drying furnace through a pipeline, and the lower ends of the primary deacidification tower and the secondary deacidification tower are sequentially connected with the circulating alkali solution return tank through a pipeline, and the right side of the circulating alkali solution return tank is connected with a circulating alkali solution neutralization tank through a pipeline, and the circulating alkali solution neutralization tank is respectively connected with the semi-dry deacidification reactor, the quenching water tower, the primary deacidification tower and the secondary deacidification tower through a pipeline, and a semi-dry deacidification reactor alkali solution spray pump is provided on the pipeline between the circulating alkali solution neutralization tank and the semi-dry deacidification reactor, and a quenching pump is provided on the pipeline between the circulating alkali solution neutralization tank and the quenching water tower, and a primary deacidification spray pump and a secondary deacidification spray pump are respectively provided on the pipeline between the circulating alkali solution neutralization tank and the two deacidification towers.

[0009] Further: the semi-dry deacidification reactor and the quenching water tower are both quenching equipment, and the quenching equipment adopts one of two forms, one is a wet method and the other is a semi-dry method. The wet method includes a semi-dry deacidification reactor and a quenching water tower, which are connected in sequence through a flue; the semi-dry method includes a semi-dry deacidification reactor, a high-temperature ceramic membrane dust collector and a quenching water tower, which are connected in sequence through a flue; the semi-dry deacidification reactor is to pass the flue gas through the semi-dry deacidification reactor alkali liquid spray pump, extract the alkali liquid in the circulating alkali liquid return tank and send it to the alkali liquid spray atomizing spray gun A, and spray the alkali liquid into the alkali liquid spray atomizing spray gun A In the semi-dry deacidification reactor, the quenching water tower passes the flue gas through a quenching pump, extracts the alkali solution in the circulating alkali solution return tank and sends it to the alkali solution spray atomizing spray gun B, and the alkali solution is sprayed into the quenching water tower by the alkali solution spray atomizing spray gun B, and neutralizes with the acidic gas in the flue gas to achieve further deacidification. The flue outlet of the semi-dry deacidification reactor is connected to a slaked lime pipeline, and the lower end of the quenching water tower is connected to a slag liquid collection tank through a pipeline. The lower end of the high-temperature ceramic membrane dust collector is connected to a desalted water pipeline on one side of the ash hopper and the ash hopper outlet is connected to the slag liquid collection tank through a pipeline, and the left side of the slag liquid collection tank is connected to an external hydrochloric acid pipeline.

[0010] Furthermore: the first-level deacidification tower and the second-level deacidification tower are both provided with three layers of alkali solution atomizing spray guns, the second-level deacidification tower is provided with a demister at the top, and the upper and lower ends of the demister are respectively provided with desalted water cleaning atomizing spray guns, and the desalted water is used to spray and clean the demister.

[0011] Further: the denitrification equipment is provided with a flue gas heater, a flue gas heating burner, and a denitrification tower. The flue gas heater is provided with a flue gas heating burner on the upper part, the lower end of the flue gas heater is connected to the denitrification tower, the upper end of the denitrification tower is provided with a denitrification ammonia spray atomizing gun, the denitrification ammonia spray atomizing gun is connected to an ammonia water pipeline, and multiple layers of low-temperature denitrification catalyst are arranged in the denitrification tower.

[0012] Further: a desalted water pipe is connected to one side of the lower ash hopper of the bag filter, the lower end of the ash hopper is connected to a wastewater tank through a pipe, the wastewater tank is also connected to a wastewater delivery pump in turn, and the wastewater delivery pump is connected to a slag liquid collection tank through a pipe.

[0013] Furthermore: the right side of the waste liquid treatment tank is connected with a pipeline for adding calcium chloride and lime milk.

[0014] Furthermore: the drum A and the drum B are both solid-liquid separation devices. The wastewater separated by the drum A is sent to the sewage treatment plant through a pipeline for reprocessing, and the separated solid salts are sent to the waste solid salt solution plus hydrochloric acid treatment tank. The waste solid salt solution plus hydrochloric acid treatment tank is equipped with an external hydrochloric acid pipeline and an agitator. The solution prepared in the waste solid salt solution plus hydrochloric acid treatment tank is sent to the waste solid salt solution plus LiOH treatment tank through the waste solid salt solution primary delivery pump, and then transported to the drum B through the waste solid salt solution secondary delivery pump; the waste solid salt solution plus LiOH treatment tank is equipped with an external LiOH solution pipeline and an agitator, the solution separated by the drum B enters the evaporator, the separated solid salt is sent to the packaging workshop for recycling, and the solution separated by the drum B enters the evaporator and crystallizes to form solid crystals after evaporation, and is sent to the drying furnace for drying.

[0015] Furthermore: the temperature in the drying furnace is controlled at 260-300°C according to the properties of the solid crystals, and a partition heat exchange method is adopted to ensure the purity of the solid and the purity of the hot air after heat exchange. The pure hot air after heat exchange can be sent to the incinerator as primary air to save energy.

[0016] 1. Incinerator:

[0017] The incineration temperature of hazardous waste materials is ≥1100℃. The incineration temperature of the incinerator is controlled at around 1200℃, and the residence time is 2s.

[0018] The solid Li2O and molten NaF generated in the incinerator will be collected into the slag liquid collection tank through the slag discharge pipe at the bottom of the incinerator for centralized treatment.

[0019] The air required for incineration in the incinerator uses the cooled hot air after the CaCl2·2H2O is dried in the drying furnace, thus achieving energy saving.

[0020] Considering the strong corrosiveness of hydrogen fluoride gas, the selection of incinerator materials must fully consider the corrosiveness of hydrogen fluoride. Hydrogen fluoride is very active and reacts to Fe and Si at any temperature. Therefore, it is necessary to select high-purity white corundum brick refractory materials and Fe and Si-free insulation materials, and use special high-temperature resistant and hydrogen fluoride corrosion-resistant coatings on the fire surface.

[0021] Considering that the waste contains a large amount of fluorine, in order to ensure that the fluorine element is converted into hydrogen fluoride as much as possible during the incineration process and to prevent hydrogen deficiency in the process of generating hydrogen fluoride, water vapor is reserved to supplement hydrogen to the furnace.

[0022] 2. Two forms: wet method and semi-dry method:

[0023] The wet method is a semi-dry deacidification reactor (i.e., the first stage quenching tower) + a second stage quenching tower, and the semi-dry method is a semi-dry deacidification reactor (i.e., the first stage quenching tower) + a high-temperature ceramic dust collector.

[0024] Semi-dry deacidification reactor

[0025] The flue gas temperature coming out of the incinerator is about 1200℃. In order to meet the use requirements of subsequent process equipment, the flue gas needs to be cooled. For hazardous waste incineration systems that process high fluorine or chlorine content greater than 5%, waste heat boilers must not be used for cooling. Here, by spraying alkali liquid into the reactor, the flue gas temperature is reduced from 1200℃ to about 550℃. At the same time, the alkali liquid can remove part of the HF gas in the flue gas.

[0026] Considering the corrosiveness of hydrogen fluoride gas and the high-temperature flue gas in the reactor, the material selection is the same as that of the incinerator, that is, high-purity white corundum brick refractory materials and Fe-free and Si-free insulation materials are selected, and special high-temperature resistant and hydrogen fluoride corrosion-resistant coatings are used on the flue gas side.

[0027] Introduction to the rapid cooling system of the semi-dry deacidification reactor: By spraying alkali liquid into the high-temperature flue gas of about 1200℃ coming out of the incinerator, the flue gas is quickly cooled down, so that the flue gas temperature drops from 1200℃ to about 550℃. At the same time, part of the HF gas in the flue gas can be removed by the alkali liquid.

[0028] The flue gas cooled from 1200℃ to about 550℃ can be treated by one of the following two methods:

[0029] Treatment method 1: Use the second stage quenching tower

[0030] In order to cool the flue gas and prevent the generation of dioxins during the cooling process, and to remove part of the HF, the system is equipped with a second-stage rapid cooling method, which sprays alkali solution to further reduce the flue gas at about 550°C coming out of the semi-dry deacidification reactor rapid cooling system to below 80°C within 1 second, and then sends it to the first-stage deacidification tower for further treatment.

[0031] High-temperature flue gas at 550°C is introduced from the upper part of the quenching tower, and the flue gas is rapidly cooled by spraying atomized quenching circulating alkali solution into the flue gas, so that the flue gas temperature is rapidly cooled to about 80°C within 1 second, and part of HF is neutralized with Ca(OH)2 to generate calcium fluoride.

[0032] The quenching spray alkali solution coming out from the bottom of the quenching water tower mainly contains Na2HPO4, NaF, LiF, CaF2 and other components, which are collected in the slag liquid collection tank for centralized treatment.

[0033] Treatment method 2: Use high temperature ceramic dust collector

[0034] After the incinerator flue gas is cooled by a semi-dry deacidification reactor, it enters a high-temperature ceramic membrane dust collector for dust removal and purification.

[0035] Since the flue gas from the incinerator contains components such as Na4P2O7, NaF, Li2O, especially the high content of Na4P2O7, when the flue gas temperature drops from 1200℃ to about 550℃, the Na4P2O7 in the flue gas will change from gaseous to solid particles. After passing through the high-temperature ceramic dust collector, the Na4P2O7, NaF, Li2O and other components in the flue gas will be filtered out, and the flue gas will be separated from the gas and solid, achieving preliminary purification treatment.

[0036] The high-temperature ceramic membrane dust collector is a high-temperature gas-solid separation device with high-performance high-temperature ceramic membrane elements as the core. It is mainly composed of high-temperature ceramic membrane elements, high-temperature dust collector shell, pulse backflush system and automatic control system.

[0037] A desalted water interface is provided on the ash hopper of the high-temperature ceramic membrane dust collector. By spraying desalted water into the ash hopper, the dust and particulate matter in the ash hopper are flushed and collected into the slag liquid collection tank for centralized treatment.

[0038] 3. Deacidification Tower

[0039] The temperature of the flue gas coming out of the quenching water tower is about 80°C, and a two-stage deacidification tower is set up to remove hydrogen fluoride gas from the flue gas.

[0040] If the incinerated lithium battery waste liquid contains a high amount of acid ions such as F- and Cl-, it is necessary to use two or more deacidification towers to achieve the neutralization reaction of F-, Cl- and other acid ions to remove them; if the incinerated lithium battery waste liquid contains a low amount of F-, Cl- and other acid ions, a single-stage deacidification tower can be used to achieve the neutralization reaction of F-, Cl- and other acid ions to remove them.

[0041] 4. Flue gas heat exchanger

[0042] The flue gas heat exchanger consists of a shell, a frame, heat exchange tubes, external insulation, flue gas measuring points, etc. The heating surface of the flue gas heat exchanger is arranged in the flue composed of the shell and the frame. The higher temperature clean flue gas after denitrification is heat exchanged with the lower temperature flue gas coming out of the secondary deacidification tower through the heat exchange tubes. The higher temperature clean flue gas after denitrification goes through the shell, and the lower temperature flue gas coming out of the secondary deacidification tower goes through the tube. The lower temperature flue gas coming out of the secondary deacidification tower enters the bag filter after heat exchange and temperature rises. After dust removal, it enters the flue gas reheating furnace for heating. After reaching the activation temperature of the denitrification catalyst, it enters the denitrification device for denitrification. The flue gas after denitrification is used as a heat source to heat the lower temperature flue gas coming out of the secondary deacidification tower in the flue gas heat exchanger. Flue gas temperature and pressure measuring points are set at reasonable positions of the flue gas heat exchanger module.

[0043] Material selection for flue gas heat exchanger: The shell and heat exchange tube carbon steel are coated with KN22 heat-resistant and corrosion-resistant paint. A frame for supporting and strengthening is welded on the outer layer of the shell. The frame adopts a composite beam made of Q235B. Insulation material is laid on the outer layer of the shell steel plate to ensure that the outer wall temperature of the flue gas heat exchanger is ≤60℃ during normal operation.

[0044] 5. Bag Dust Collector

[0045] Material selection for bag dust collector: filter bags are made of PTFE, and patterned plates, bag cages and the inner side of the box are made of carbon steel coated with KN22 heat-resistant and corrosion-resistant paint.

[0046] A desalted water interface is provided on the ash hopper of the bag filter. By spraying desalted water into the ash hopper, the dust and particulate matter in the ash hopper are flushed out and collected in a wastewater tank, which is then pumped into a slag liquid collection tank for centralized treatment.

[0047] 6. Denitrification equipment: Combination of heater and SCR denitrification tower

[0048] The flue gas discharged from the bag filter through gas-solid separation enters the flue gas heater, and after being reheated to the activation temperature of the denitrification catalyst of the denitrification device by burning natural gas, it enters the denitrification device to remove NOx in the flue gas.

[0049] The SCR denitration device is mainly composed of an external steel frame, an external steel plate, an inner lining protection furnace wall, a catalyst bracket and an SCR denitration catalyst. The SCR denitration catalyst is a medium-low temperature catalyst with an operating temperature between 260 and 400°C and a service life of ≥5 years. Material selection for the SCR deacidification device: The material of the part of the denitration device that contacts the flue gas is carbon steel coated with KN22 heat-resistant and corrosion-resistant paint.

[0050] 7. Flue gas emissions

[0051] The purified flue gas after deacidification and denitration is cooled by the flue gas heat exchanger and then sent to the chimney by the induced draft fan for exhaust. The material of the induced draft fan and the parts in contact with the flue gas is carbon steel with KN22 heat-resistant and corrosion-resistant paint. The main material of the chimney is carbon steel with KN22 heat-resistant and corrosion-resistant paint.

[0052] 8. Salt recovery and treatment:

[0053] 1. The recyclables generated by the incinerator, quenching water tower, deacidification tower and bag filter are all collected in the slag liquid collection tank for centralized treatment. The main components are: Na2HPO4, NaF, LiF, CaF2, etc.

[0054] 2. First, add hydrochloric acid to the slag liquid collection tank to make the pH value of the solution in the tank less than 3, so that it is converted into NaCl, CaF2, LiF, Na2HPO4, etc.

[0055] 3. The adjusted solution flows from the slag liquid collection tank into the waste liquid treatment tank.

[0056] 4. Add calcium chloride aqueous solution and lime milk to the waste liquid treatment tank, where Ca2+ reacts with F- to form CaF2, which is insoluble in water. At the same time, Li+ reacts with F- to form LiF, which is also insoluble in water.

[0057] Ca2++2F-→CaF2↓

[0058] Li++F-→LiF↓

[0059] 5. The slurry at the bottom of the waste liquid treatment tank is led out by a slurry pump and dehydrated by a rotary drum to separate the waste solid salt (CaF2, LiF, etc.). Part of the wastewater separated by the rotary drum is returned to the circulating alkali liquid return tank, and part is discharged to the wastewater treatment plant.

[0060] 6. Send the separated waste solid salt (CaF2, LiF) to the waste solid salt treatment tank 1, add hydrochloric acid solution to the tank for mixing, and ensure that the temperature of the solution is below 10°C. Under this condition, CaF2 will dissolve in the hydrochloric acid solution and convert into CaCl2, while LiF is insoluble in the hydrochloric acid solution. Use a slurry pump to draw out the solution in the waste solid salt treatment tank 1 and send it to the waste solid salt treatment tank 2. Add LiOH to the waste solid salt treatment tank 2, and the Li+ in LiOH will react with the F- in the solution to generate LiF. The reaction process is as follows:

[0061] CaF2+2HCl→CaCl2+HF

[0062] LiOH+HF→LiF↓+H2O

[0063] The solution in the waste solid salt treatment tank 2 is led out by a slurry pump, and dehydrated by a rotary drum to separate the LiF solid, and the aqueous solution will only contain CaCl2. The CaCl2 aqueous solution separated by the rotary drum is evaporated to recover CaCl2·2H2O, and then dried to recover anhydrous calcium chloride.

[0064] The beneficial effects of the present invention are: further refinement and optimization of the combination of equipment through existing equipment, more reasonable treatment of waste liquid, and rational and maximum treatment and utilization of waste liquid. The specific effects are as follows:

[0065] 1. The incinerator burns fully and effectively, completely burning the organic matter in the lithium battery waste liquid, and converting the alkali metals contained therein into Na4P2O7, NaF, Li2O and other components;

[0066] 2. Double-stage cooling can instantly reduce the flue gas to 80℃ (<1s), and circulating alkali solution is used to cool it down, effectively preventing the formation of dioxins;

[0067] 3. Set up a flue gas heat exchanger to rationally utilize the flue gas temperature in the system to achieve energy saving and consumption reduction;

[0068] 4. Use scientific means to turn waste into treasure, recycle expensive LiF and anhydrous calcium chloride in the market, and realize the resource utilization of waste.

[0069] The invention has reasonable design and compact structure. The treated flue gas fully meets the national environmental protection requirements. The enterprise can choose the wet treatment method or the dry treatment method based on comprehensive consideration. The invention is flexible and suitable for popularization and use. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] Figure 1 It is a schematic diagram of the wet process of the present invention;

[0071] Figure 2 This is a schematic diagram of the semi-dry process of the present invention;

[0072] Figure 3 A partial enlarged view of the wet combination method;

[0073] Figure 4 Partially enlarged view of the semi-dry combination method.

[0074] In the figure: 1. Incinerator, 2. Semi-dry deacidification reactor, 3. Primary deacidification tower, 4. Secondary deacidification tower, 5. Flue gas heat exchanger, 6. Bag dust collector, 7. Denitrification equipment, 8. Chimney, 9. Drying furnace, 10. Drum A, 11. Waste liquid storage tank, 12. Slag liquid collection tank, 13. Waste liquid treatment tank, 14. Circulating alkali liquid return tank, 15. Circulating alkali liquid neutralization tank, 16. Wastewater tank, 17. Evaporator, 18. Waste solid salt solution plus LiOH treatment tank, 19. Quick cooling pump, 20. Primary deacidification spray pump, 21. Secondary deacidification spray pump, 22. Semi-dry deacidification reactor alkali liquid spray pump, 23. Circulating alkali liquid delivery pump, 24. Wastewater Delivery pump, 25. Waste liquid delivery pump, 26. Induced draft fan, 27. Screw delivery pump, 28. Waste liquid atomizing spray gun, 29. Auxiliary fuel burner, 30. Alkali solution spray atomizing spray gun A, 31. Alkali solution spray atomizing spray gun B, 32. Desalted water cleaning atomizing spray gun, 33. Defogger, 34. Flue gas heater, 35. Denitrification ammonia spray atomizing spray gun, 36. Denitrification tower, 37. Flue gas heating burner, 38. Drum B, 39. First-stage delivery pump for waste solid salt solution, 40. Second-stage delivery pump for waste solid salt solution, 41. Waste solid salt solution plus hydrochloric acid treatment tank, 42. High-temperature ceramic membrane dust collector, 43. Rapid cooling water tower, 44. Low-temperature denitrification catalyst. DETAILED DESCRIPTION

[0075] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0076] See also Figure 1-Figure 4 The present invention provides a technical solution: comprising an incinerator 1, a semi-dry deacidification reactor 2, a primary deacidification tower 3, a secondary deacidification tower 4, a flue gas heat exchanger 5, a bag filter 6, a denitrification device 7, a chimney 8, a drying furnace 9 and an evaporator 17, wherein a waste liquid atomizing spray gun 28 arranged on the wall of the incinerator 1 is connected to a waste liquid storage tank 11 and two screw delivery pumps 27, one for backup and the other for use, through a pipeline, an auxiliary fuel burner 29 is arranged on the wall of the incinerator 1, and a flue gas outlet of the incinerator 1 is sequentially connected to the semi-dry deacidification reactor 2, a quenching device 7, a chimney 8, a drying furnace 9 and an evaporator 17. A water tower 43, a primary deacidification tower 3, a secondary deacidification tower 4, a flue gas heat exchanger 5, a bag filter 6, a denitration device 7 and a chimney 8. The flue gas outlet flue of the denitration device 7 is connected to the flue gas inlet of the flue gas heat exchanger 5. The flue gas outlet of the flue gas heat exchanger 5 is provided with an induced draft fan 26 connected to the lower end of the chimney 8. The lower side of the incinerator 1 is connected to a slag liquid collection tank 12 and a waste liquid treatment tank 13 in sequence through pipelines. The waste liquid treatment tank 13 is connected to a waste liquid delivery pump 25, a rotary drum A10, and a waste solid salt solution adding hydrochloric acid treatment tank 41 in sequence through pipelines. The waste solid salt solution adding hydrochloric acid treatment tank 41 is then connected to two waste solid salt solution primary delivery pumps 39 for standby use and the waste solid salt solution adding LiOH treatment tank 18 through a pipeline. The waste solid salt solution adding LiOH treatment tank 18 is sequentially connected to the waste solid salt solution secondary delivery pump 40, the drum B38, the evaporator 17, and the drying furnace 9 through a pipeline. The lower ends of the primary deacidification tower 3 and the secondary deacidification tower 4 are sequentially connected to the circulating alkali solution return tank 14 through a pipeline. The right side of the circulating alkali solution return tank 14 is connected to the circulating alkali solution through a pipeline. A neutralization tank 15, wherein the circulating alkali solution neutralization tank 15 is connected to the semi-dry deacidification reactor 2, the quenching water tower 43, the primary deacidification tower 3 and the secondary deacidification tower 4 through pipelines, respectively; a semi-dry deacidification reactor alkali solution spray pump 22 is provided on the pipeline between the circulating alkali solution neutralization tank 15 and the semi-dry deacidification reactor 2; a quenching pump 19 is provided on the pipeline between the circulating alkali solution neutralization tank 15 and the quenching water tower 43; a primary deacidification spray pump 20 and a secondary deacidification spray pump 21 are provided on the pipeline between the circulating alkali solution neutralization tank 15 and the two deacidification towers, respectively.

[0077] The semi-dry deacidification reactor 2 and the quenching water tower 43 are both quenching equipment, and the quenching equipment adopts one of two forms, one of which belongs to the wet method. One belongs to the semi-dry method, and the wet method includes the semi-dry deacidification reactor 2 and the quenching water tower 43, and they are connected in sequence through the flue; the semi-dry method includes the semi-dry deacidification reactor 2, the high-temperature ceramic membrane dust collector 42 and the quenching water tower 43, and they are connected in sequence through the flue; the semi-dry deacidification reactor 2 is to pass the high-temperature flue gas above 1100°C through the semi-dry deacidification reactor alkali liquid spray pump 22, extract the alkali liquid in the circulating alkali liquid return tank 14 and send it to the alkali liquid spray atomizing spray gun A30, and spray the alkali liquid into the semi-dry deacidification reactor 2 by the alkali liquid spray atomizing spray gun A30, and rapidly cool the flue gas to about 550°C, and neutralize it with the acidic gas in the flue gas to achieve deacidification. The quenching water tower 43 is to pass the high-temperature flue gas of 550°C through the quenching pump 19, extract the alkali solution in the circulating alkali solution return tank 14 and send it to the alkali solution spray atomizing spray gun B31, and spray the alkali solution into the quenching water tower 43 by the alkali solution spray atomizing spray gun B31, so as to rapidly cool the flue gas to less than about 200°C, and react with the acidic gas in the flue gas to achieve further deacidification. The flue outlet of the semi-dry deacidification reactor 2 is connected to a slaked lime pipeline, the lower end of the quenching water tower 43 is connected to the slag liquid collection tank 12 through a pipeline, the lower end of the high-temperature ceramic membrane dust collector 42 is connected to a desalted water pipeline on one side of the ash hopper and the ash hopper outlet is connected to the slag liquid collection tank 12 through a pipeline, and the left side of the slag liquid collection tank 12 is connected to an external hydrochloric acid pipeline.

[0078] The first-stage deacidification tower 3 and the second-stage deacidification tower 4 are both provided with three layers of alkali solution spray guns. The second-stage deacidification tower 4 is provided with a demister 33 at the top. The upper and lower ends of the demister 33 are respectively provided with desalted water cleaning atomizing spray guns 32. The demister 33 is sprayed and cleaned with desalted water.

[0079] The denitrification equipment 7 is provided with a flue gas heater 34, a flue gas heating burner 37, and a denitrification tower 36. The flue gas heating burner 37 is arranged on the upper part of the flue gas heater 34, and the lower end of the flue gas heater 34 is connected to the denitrification tower 36. The upper end of the denitrification tower 36 is provided with a denitrification ammonia spray atomizing gun 35, and the denitrification ammonia spray atomizing gun 35 is connected to an ammonia water pipeline. Multiple layers of low-temperature denitrification catalyst 44 are arranged in the denitrification tower 36.

[0080] A desalted water pipeline is connected to one side of the lower ash hopper of the bag filter 6, and the lower end of the ash hopper is connected to a wastewater tank 16 through a pipeline. The wastewater tank 16 is also connected to a wastewater delivery pump 24 in turn, and the wastewater delivery pump 24 is connected to the slag liquid collection tank 12 through a pipeline.

[0081] The right side of the waste liquid treatment tank 13 is connected with a pipeline for adding calcium chloride and lime milk.

[0082] The drum A10 and the drum B38 are both solid-liquid separation devices. The wastewater separated by the drum A10 is sent to the sewage treatment plant through a pipeline for reprocessing, and the separated solid salts are sent to the waste solid salt solution adding hydrochloric acid treatment tank 41. The waste solid salt solution adding hydrochloric acid treatment tank 41 is equipped with an external hydrochloric acid pipeline and a stirrer device. The amount of hydrochloric acid added is adjusted according to the pH value of the solution in the waste solid salt solution adding hydrochloric acid treatment tank 41. At the same time, the stirrer is used to stir to ensure that the solution in the waste solid salt solution adding hydrochloric acid treatment tank 41 is uniform. The solution prepared according to the pH value requirement in the waste solid salt solution adding hydrochloric acid treatment tank 41 is sent to the waste by the waste solid salt solution primary delivery pump 39. The solid salt solution is added to the LiOH treatment tank 18, and an aqueous solution of LiF and CaCl2 is formed by adding LiOH and stirring, and then transported to the drum B38 through the waste solid salt solution secondary delivery pump 40; the waste solid salt solution is added to the LiOH treatment tank 18 and is equipped with an external LiOH solution pipeline and a stirrer device. The solution separated by the drum B38 enters the evaporator 17, and the separated solid salt, i.e., LiF, is sent to the packaging workshop for recycling. The CaCl2 solution separated by the drum B38 enters the evaporator 17 and evaporates and then crystallizes to form solid CaCl2.2H2O crystals, which are sent to the drying furnace 9 for drying and then packaged for recovery of anhydrous CaCl2;

[0083] The drying furnace 9 controls the temperature inside the furnace to 260-300°C according to the requirements of the physical properties of solid CaCl2.2H2O crystals, and adopts a partition heat exchange method to ensure the purity of the anhydrous CaCl2 solid and the purity of the hot air after heat exchange. The pure hot air after heat exchange can be sent to the incinerator 1 as primary air to save energy.

[0084] When using the present invention, the components of the waste liquid are first analyzed. This patent is successfully developed based on the following components of lithium battery waste liquid. The main components of lithium battery waste liquid are: carbonate, PVDF, phosphate, fluoride salt, carbon, water, etc., and its related physical properties are as follows:

[0085] 1. Carbonates: Ethyl carbonate is used as a representative substance for related physical property analysis.

[0086] The molecular formula of ethyl carbonate is C5H10O3, the molecular weight is 118, it is a colorless liquid, the melting point is -43℃, the boiling point is 125.8℃, it is insoluble in water, but soluble in most organic solvents such as alcohols, ketones, and esters.

[0087] Ethyl carbonate is flammable, and its combustion (decomposition) products are carbon monoxide and carbon dioxide.

[0088] 2. PVDF: PVDF is the abbreviation of polyvinylidene fluoride, which mainly refers to vinylidene fluoride homopolymer or copolymer of vinylidene fluoride and other small amounts of fluorine-containing vinyl monomers, with the molecular formula -(CH2-CF2)n-.

[0089] According to relevant information, PVDF can be treated by incineration. However, since PVDF will produce HF gas after thermal decomposition, relevant equipment and measures are required to deal with the HF gas.

[0090] 3. Phosphate is mainly disodium hydrogen phosphate, with the molecular formula of Na2HPO4 and molecular weight of 142. It appears as white powder, flakes or granules, soluble in water, and decomposes into sodium pyrophosphate at 250°C.

[0091] The molecular formula of sodium pyrophosphate is Na4P2O7, the molecular weight is 266, and the appearance is white powder or crystal. The melting point is 880℃, the boiling point is 938℃, it is easily soluble in water, and the aqueous solution is stable below 70℃. It will hydrolyze into disodium hydrogen phosphate when boiled.

[0092] 4. Fluoride salts are mainly lithium salts and sodium salts

[0093] Sodium fluoride: Molecular formula is NaF, molecular weight is 42. Melting point is 993℃, boiling point is 1695℃, soluble in water. Sodium fluoride is toxic.

[0094] Lithium fluoride: Molecular formula is LiF, molecular weight is 26. It is white crystal at room temperature, slightly soluble in water, and easily soluble in acid at room temperature. Melting point is 848℃, boiling point is 1681℃. This product is toxic. It decomposes in high heat to produce hydrogen fluoride and lithium oxide.

[0095] The two processing methods are as follows:

[0096] 1. Semi-dry treatment process: incinerator 1 → semi-dry deacidification reactor 2 → high temperature ceramic dust collector 42 → quenching water tower 43 → primary deacidification tower 3 → secondary deacidification tower 4 → heat exchanger 5 → bag filter 6 → flue gas heater 34 → denitrification equipment 7 → flue gas heat exchanger 5 → induced draft fan 26 → chimney 8;

[0097] Liquid and solid salts generated by incineration in incinerator 1 + solid salts collected by high-temperature ceramic dust collector 42 → slag liquid collection tank (add hydrochloric acid with a PH ratio of <3 acidic solution) → waste liquid treatment tank (add calcium chloride aqueous solution and lime milk solution for neutralization) → rotary drum (solid-liquid separation, liquid sent to sewage treatment plant for treatment) → solid salt sent to waste solid salt treatment tank 1 (add hydrochloric acid, and stir and cool the solution to <10°C) → solid salt sent to waste solid salt treatment tank 2 (add LiOH, and stir and cool the solution to <10°C) → rotary drum (solid-liquid separation, recovery of solid LiF) → evaporator → drying furnace → recovery of anhydrous calcium chloride.

[0098] 2. Wet treatment process: incinerator 1 → semi-dry deacidification reactor 2 → quenching tower 43 → primary deacidification tower 3 → secondary deacidification tower 4 → heat exchanger 5 → bag filter 6 → flue gas heater 34 → denitrification equipment 7 → flue gas heat exchanger 5 → induced draft fan 26 → chimney 8;

[0099] Liquid and solid salts generated by incineration in incinerator 1 + liquid and solid salts collected by quenching water tower 43 → slag liquid collection tank (external addition of hydrochloric acid with a pH ratio of <3 acidic solution) → waste liquid treatment tank (external addition of calcium chloride aqueous solution and lime milk solution for neutralization treatment) → rotary drum (solid-liquid separation, liquid sent to sewage treatment plant for treatment) → solid salt sent to waste solid salt treatment tank 1 (external addition of hydrochloric acid, and the solution is stirred and cooled to <10°C) → solid salt sent to waste solid salt treatment tank 2 (external addition of LiOH, and the solution is stirred and cooled to <10°C) → rotary drum (solid-liquid separation, recovery of solid LiF) → evaporator → drying furnace → recovery of anhydrous calcium chloride.

[0100] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A lithium battery waste liquid resource recovery and environmental protection treatment system, comprising an incinerator (1), a semi-dry deacidification reactor (2), a primary deacidification tower (3), a secondary deacidification tower (4), a flue gas heat exchanger (5), a bag filter (6), a denitrification device (7), a chimney (8), a drying furnace (9) and an evaporator (17), characterized in that: The waste liquid atomizing spray gun (28) arranged on the furnace wall of the incinerator (1) is connected to a waste liquid storage tank (11) and two screw conveying pumps (27) for backup and use through pipelines. An auxiliary fuel burner (29) is arranged on the furnace wall of the incinerator (1). The flue gas outlet of the incinerator (1) is connected to a semi-dry deacidification reactor (2), a quenching water tower (43), a primary deacidification tower (3), a secondary deacidification tower (4), a flue gas heat exchanger (5), a bag filter (6), a denitration device (7) and a chimney (8) in sequence through a flue. The flue gas outlet flue of the denitration device (7) is connected to the flue gas inlet of the flue gas heat exchanger (5). The flue gas outlet of the flue gas heat exchanger (5) is provided with an induced draft fan. The incinerator (26) is connected to the lower end of the chimney (8); the lower side of the incinerator (1) is connected to a slag liquid collection tank (12) and a waste liquid treatment tank (13) in sequence through pipelines; the waste liquid treatment tank (13) is connected to a waste liquid delivery pump (25), a rotary drum A (10), and a waste solid salt solution adding hydrochloric acid treatment tank (41) in sequence through pipelines; the waste solid salt solution adding hydrochloric acid treatment tank (41) is further connected to two waste solid salt solution primary delivery pumps (39) for one standby and one for the other with a waste solid salt solution adding LiOH treatment tank (18) through pipelines; the waste solid salt solution adding LiOH treatment tank (18) is connected to a waste solid salt solution secondary delivery pump (40), a rotary drum A (10), and a waste solid salt solution adding hydrochloric acid treatment tank (41) in sequence through pipelines. B (38), an evaporator (17), and a drying furnace (9); the lower ends of the primary deacidification tower (3) and the secondary deacidification tower (4) are connected in sequence to a circulating alkali solution return tank (14) through pipelines; the right side of the circulating alkali solution return tank (14) is connected to a circulating alkali solution neutralization tank (15) through a pipeline; the circulating alkali solution neutralization tank (15) is connected to a semi-dry deacidification reactor (2), a quenching water tower (43), the primary deacidification tower (3), and the secondary deacidification tower (4) through pipelines; a semi-dry deacidification reactor alkali solution spray pump (22) is provided on the pipeline between the circulating alkali solution neutralization tank (15) and the semi-dry deacidification reactor (2); and the circulating alkali solution neutralization tank (15) is connected to the quenching water tower (43). A quenching pump (19) is provided on the pipeline between the water towers (43); a primary deacidification spray pump (20) and a secondary deacidification spray pump (21) are respectively provided on the pipeline between the circulating alkali solution neutralization tank (15) and the two deacidification towers; the semi-dry deacidification reactor (2) and the quenching water tower (43) are both quenching equipment, and the quenching equipment adopts one of two forms, one is a wet method and the other is a semi-dry method, the wet method comprises a semi-dry deacidification reactor (2) and a quenching water tower (43), and they are connected in sequence through a flue; the semi-dry method comprises a semi-dry deacidification reactor (2), a high-temperature ceramic membrane dust collector (42) and a quenching water tower (43), and they are connected in sequence through a flue;The semi-dry deacidification reactor (2) passes the flue gas through the semi-dry deacidification reactor alkali liquid spray pump (22), extracts the alkali liquid in the circulating alkali liquid return tank (14) and sends it to the alkali liquid spray atomizing spray gun A (30), and sprays the alkali liquid into the semi-dry deacidification reactor (2) in an atomized form through the alkali liquid spray atomizing spray gun A (30), and the quenching water tower (43) passes the flue gas through the quenching pump (19), extracts the alkali liquid in the circulating alkali liquid return tank (14) and sends it to the alkali liquid spray atomizing spray gun B (31), and sprays the alkali liquid into the quenching water tower (43) in an atomized form through the alkali liquid spray atomizing spray gun B (31). , and further deacidification is achieved by neutralizing the acidic gas in the flue gas. The flue outlet of the semi-dry deacidification reactor (2) is connected to a slaked lime pipeline. The lower end of the quenching water tower (43) is connected to the slag liquid collection tank (12) through a pipeline. The lower end of the high-temperature ceramic membrane dust collector (42) is connected to a desalted water pipeline on one side of the ash hopper and the ash hopper outlet is connected to the slag liquid collection tank (12) through a pipeline. The left side of the slag liquid collection tank (12) is connected to an external hydrochloric acid pipeline. The first deacidification tower (3) and the second deacidification tower (4) are both provided with three-layer alkali liquid atomizing spray guns. The second deacidification tower (4) A demister (33) is provided at the top of the interior, and desalted water cleaning atomizing spray guns (32) are respectively provided at the upper and lower ends of the demister (33), and the desalted water is used to spray and clean the demister (33); the drum A (10) and the drum B (38) are both solid-liquid separation devices, and the waste water separated by the drum A (10) is sent to a sewage treatment plant through a pipeline for reprocessing, and the separated solid salts are sent to a waste solid salt solution adding hydrochloric acid treatment tank (41), and the waste solid salt solution adding hydrochloric acid treatment tank (41) is equipped with an external hydrochloric acid pipeline and a stirrer. The prepared solution is sent to the waste solid salt solution adding LiOH treatment tank (18) through the waste solid salt solution primary delivery pump (39), and then sent to the drum B (38) through the waste solid salt solution secondary delivery pump (40); the waste solid salt solution adding LiOH treatment tank (18) is equipped with an external LiOH solution pipeline and a stirrer, the solution separated by the drum B (38) enters the evaporator (17), the separated solid salt is sent to the packaging workshop for recycling, the solution separated by the drum B (38) enters the evaporator (17) and evaporates and crystallizes to form solid crystals, which are sent to the drying furnace (9) for drying.

2. A lithium battery waste liquid resource recovery and environmental protection treatment system according to claim 1, characterized in that: The denitration equipment (7) is provided with a flue gas heater (34), a flue gas heating burner (37), and a denitration tower (36). The flue gas heater (34) is provided with a flue gas heating burner (37) at the top, the flue gas heater (34) is connected to the denitration tower (36) at the bottom, a denitration ammonia spraying atomizing gun (35) is provided at the top of the denitration tower (36), the denitration ammonia spraying atomizing gun (35) is connected to an ammonia water pipeline, and multiple layers of low-temperature denitration catalyst (44) are arranged in the denitration tower (36).

3. A lithium battery waste liquid resource recovery and environmental protection treatment system according to claim 1, characterized in that: A desalted water pipeline is connected to one side of the lower ash hopper of the bag filter (6); the lower end of the ash hopper is connected to a wastewater tank (16) via a pipeline; the wastewater tank (16) is also connected in turn to a wastewater delivery pump (24); and the wastewater delivery pump (24) is connected to a slag liquid collection tank (12) via a pipeline.

4. A lithium battery waste liquid resource recovery and environmental protection treatment system according to claim 1, characterized in that: The right side of the waste liquid treatment tank (13) is connected with a pipeline for adding calcium chloride and lime milk.

5. A lithium battery waste liquid resource recovery and environmental protection treatment system according to claim 1, characterized in that: The drying furnace (9) controls the temperature inside the furnace to 260-300°C according to the properties of the solid crystals, and adopts a partition heat exchange method to ensure the purity of the solid and the purity of the hot air after heat exchange. The hot air after heat exchange is sent to the incinerator (1) as primary air to save energy.

6. A process using a lithium battery waste liquid resource recovery and environmental protection treatment system as claimed in any one of claims 1 to 5, wherein the process flow is as follows: 1) The incinerator (1) incinerates waste liquid, waste gas and waste solid, and the incineration temperature is controlled at about 1200° C. The residence time is 2 seconds. The solid Li2O and molten NaF generated in the incinerator (1) are collected into a slag liquid collection tank (12) through a slag discharge pipe at the bottom of the incinerator for centralized treatment; 2) A wet method is used for cooling. The semi-dry deacidification reactor (2) cools the flue gas from 1200°C to 550°C, and then cools the flue gas from 550°C to 80°C through a secondary cooling process in a quenching water tower (43). The flue gas residence time is less than 1 second. The quenching spray alkali solution from the bottom of the quenching water tower (43), which mainly contains Na2HPO4, NaF, LiF, CaF2 and other components, is collected in a slag liquid collection tank for centralized treatment. 3) HF gas needs to be removed from the cooled flue gas, and two deacidification towers are used for removal; 4) The flue gas from which the HF gas has been removed is treated by a flue gas heat exchanger (5) and a bag filter (6); 5) The flue gas is reheated by the flue gas heater (34) and enters the denitrification device (7) for denitrification to remove NOx in the flue gas. The denitrification operation temperature is between 260 and 400° C.; 6) The flue gas that has met the deacidification and denitration standards is discharged into the chimney (8) through the induced draft fan (26); 7) The recyclables produced by the incinerator (1), the quenching water tower (43), the deacidification tower and the bag filter (6) are all collected in a slag liquid collection tank for centralized treatment. The main components are: Na2HPO4, NaF, LiF, CaF2, etc. First, hydrochloric acid is added to the slag liquid collection tank (12) to make the pH value of the solution in the tank less than 3, so that it is converted into NaCl, CaF2, LiF, Na2HPO4, etc. The adjusted solution flows from the slag liquid collection tank into the waste liquid treatment tank (13); 8) adding a calcium chloride aqueous solution and lime milk to the waste liquid treatment tank (13), wherein Ca2+ reacts with F- to form CaF2, which is insoluble in water; At the same time, Li+ reacts with F- to form LiF, which is also a substance insoluble in water. Ca2++2F-→CaF2↓ Li++F-→LiF↓ 9) The slurry at the bottom of the waste liquid treatment tank (13) is drawn out by a waste liquid delivery pump (25), and dehydrated by a rotary drum A (10) to separate the waste solid salt. A portion of the separated waste water is returned to the circulating alkali liquid return tank (14), and a portion is discharged to a wastewater treatment plant; 10) The separated waste solid salt is sent to the waste solid salt solution adding hydrochloric acid treatment tank (41), and hydrochloric acid solution is added to the tank for mixing, and the temperature of the solution is ensured to be lower than 10° C. Under this condition, CaF2 will dissolve in the hydrochloric acid solution and be converted into CaCl2, while LiF is insoluble in the hydrochloric acid solution. The solution is introduced into the waste solid salt solution adding LiOH treatment tank (18) by a pump and LiOH is added. Li+ in LiOH will react with F- in the solution to generate LiF. The reaction process is as follows: CaF2+2HCl→CaCl2+HF LiOH+HF→LiF↓+H2O 11) The treated solution is dehydrated by a rotary drum B (38) to separate the LiF solid, and the aqueous solution contains only the CaCl2 component. The separated CaCl2 aqueous solution is passed through an evaporator (17) to recover CaCl2·2H2O, and then passed through a drying furnace (9) to recover anhydrous calcium chloride.

7. The process of a lithium battery waste liquid resource recovery and environmental protection treatment system according to claim 6, characterized in that: Another combination of the step 2) is a semi-dry method, in which a high-temperature ceramic membrane dust collector (42) is provided between the quenching water tower (43) and the semi-dry deacidification reactor (2) for gas-solid separation, thereby increasing the service life of the bag dust collector (6) at the rear.

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