A system and method for recycling spent zinc oxide desulfurizer

Abstract

A kind of regeneration and utilization system and regeneration and utilization method of waste zinc oxide desulfurizer belong to desulfurizer technical field.A kind of regeneration and utilization system of waste zinc oxide desulfurizer, including high-temperature oxidation calcination device, acid leaching device, synthesis reaction device, low-temperature calcining device, also including flue gas dust removal device, desulfurization device, high-temperature flue gas discharge line, calcination material side branch line, desulfurization material return line, calcining flue gas return line, dust removal flue gas return line and dust removal flue gas waste heat utilization line.By above-mentioned system, it is realized that waste desulfurizer regeneration process will not cause secondary pollution of sulfur emission, reduce zinc loss, make waste desulfurizer material complete recycling, improve regeneration rate, reduce energy consumption.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of desulfurizer, in particular to a regeneration and utilization system and method of waste zinc oxide desulfurizer. BACKGROUND

[0002] Zinc oxide desulfurizer occupies an important position in the field of industrial fine desulfurization due to its high desulfurization precision, simple use, stable and reliable performance, and is widely used in synthetic ammonia, hydrogen production, synthetic methanol, coal chemical industry, petroleum refining and other industries. In the desulfurization process, zinc oxide desulfurizer reacts with H2S in the material to be desulfurized to generate ZnS, which solidifies the gaseous sulfur in the material to be desulfurized, achieving the purpose of desulfurization, and most of the desulfurized zinc oxide is converted into ZnS and loses activity. The annual domestic emission of zinc oxide desulfurization waste is tens of thousands of tons, resulting in high operating cost of the desulfurization system, and the stacked desulfurization waste occupies a large amount of land and causes secondary pollution to the environment. Therefore, in order to reduce the cost of desulfurizer and reduce environmental pollution, it is necessary to regenerate the zinc oxide desulfurization waste.

[0003] In the prior art, the regeneration method of zinc oxide desulfurization waste often adopts fire oxidation regeneration + wet acid leaching process. For example, Chinese patent document CN 103626221A discloses a method for regenerating and utilizing zinc oxide desulfurization waste and producing ammonium sulfate in parallel, which comprises the following steps: (1) calcination: calcining zinc oxide desulfurization waste at 850-900℃ to obtain non-active zinc oxide material; (2) acid dissolution: obtaining filter residue and zinc sulfate filtrate; (3) neutralization: adding solid ammonium bicarbonate to the zinc sulfate filtrate in step (2) and reacting at 30-40℃, controlling the pH value of the solution to be 6.8-6.9 during the reaction process until the reaction is completed; (4) aging: keeping the pH value of the solution after the reaction in step (3) unchanged, raising the solution temperature to 60-70℃, and continuing to heat and age to obtain alkali zinc carbonate filter cake and ammonium sulfate solution; (5) ammonium sulfate recovery: recovering the ammonium sulfate solution in step (4) to obtain solid ammonium sulfate; (6) active zinc oxide regeneration: washing, drying and then calcining the alkali zinc carbonate filter cake in step (4) to obtain active zinc oxide.

[0004] The above-mentioned technology regenerates and utilizes waste zinc oxide desulfurizer by adopting fire + wet process, but part of elemental zinc is volatilized in the fire oxidation process, resulting in zinc loss, and finally resulting in low regeneration rate of zinc oxide desulfurization waste. The sulfur-containing oxidation flue gas emitted in the fire oxidation process causes secondary pollution, which is equivalent to secondary desulfurization when using desulfurization equipment for treatment, increasing the treatment cost and wasting resources. In addition, the technology does not carry out waste heat recovery and utilization, resulting in high energy consumption and high carbon emission.

[0005] Chinese patent CN201610946195.8 discloses a method for regenerating zinc oxide desulfurization waste agent, comprising the following steps: (1) oxygen roasting of zinc oxide desulfurization waste agent to obtain non-active zinc oxide material and waste gas; (2) washing the waste gas with sulfuric acid to collect the washing liquid, in step (2), the waste gas is in turn contacted with 25-35wt% sulfuric acid solution and 3-5wt% sulfuric acid solution countercurrently; (3) mixing the non-active zinc oxide material with the washing liquid to carry out metathesis reaction, and after the reaction is completed, first solid-liquid separation is carried out to obtain a first liquid phase; (4) reacting the first liquid phase with ammonium carbonate and / or ammonium bicarbonate, and controlling the pH value of the reaction system to be 7 during the reaction until the reaction is completed; (5) keeping the pH value of the solution after the reaction in step (4) unchanged, raising the temperature of the solution to 60-70 DEG C and aging, and after the aging is completed, second solid-liquid separation is carried out to obtain a second solid phase; (6) drying and roasting the second solid phase in turn to obtain active zinc oxide.

[0006] The above technology regenerates and utilizes waste zinc oxide desulfurizer by adopting fire method + wet process, the technology recovers the desulfurizer and zinc oxide in the waste gas by washing the waste gas with sulfuric acid, and reduces the loss of zinc, but the technology fails to recover sulfur dioxide in the flue gas, resulting in environmental pollution.

[0007] According to the above problems, the regeneration and utilization system of waste zinc oxide desulfurizer needs to be improved to realize that the waste desulfurizer regeneration process does not cause secondary pollution of sulfur emission, the loss of zinc is reduced, the waste desulfurizer material is completely recycled, the regeneration rate is improved, and the energy consumption is reduced. SUMMARY

[0008] The present application provides a regeneration and utilization system and method of waste zinc oxide desulfurizer, which can reduce the secondary pollution of sulfur emission in the waste desulfurizer regeneration process, reduce the loss of zinc, make the waste desulfurizer material realize complete recycling through internal closed loop circulation, the regeneration rate can reach more than 98%, and the waste heat can be fully utilized to reduce the process energy consumption, reduce carbon emission, and save energy and reduce consumption.

[0009] Embodiments of the present application are implemented as follows:

[0010] In a first aspect, the present application provides a regeneration and utilization system of waste zinc oxide desulfurizer, comprising a high-temperature oxidation roasting device, an acid leaching device, a synthesis reaction device, a low-temperature calcination device, and further comprising a flue gas dust removal device, a desulfurization device, a high-temperature flue gas discharge line, a roasting material side branch line, a desulfurization material return line, a calcination flue gas return line, a dust removal flue gas return line and a dust removal flue gas waste heat utilization line;

[0011] One end of the high-temperature flue gas discharge line is connected to the high-temperature oxidation roasting device, and the other end is connected to the flue gas dust removal device;

[0012] The roasting material side branch line is connected to the material output line of the high-temperature oxidative roasting device at one end and to the desulfurization device at the other end;

[0013] The desulfurized material return line is connected to the acid leaching device at one end and to the desulfurization device at the other end;

[0014] The calcination flue gas return line is connected to the low-temperature calcination device at one end and to the desulfurization device at the other end;

[0015] The dedusted flue gas return line is connected to the low-temperature calcination device at one end and to the desulfurization device at the other end;

[0016] The dedusted flue gas waste heat utilization line is connected to the flue gas dedusting device at one end and to the low-temperature calcination device at the other end.

[0017] Further, a dedusting ash conveying line is further included, which is connected to the flue gas dedusting device at one end and to the desulfurization device at the other end; the low-temperature calcination device includes a radiation pipe, and the hot dedusted flue gas is introduced into the radiation pipe through the dedusted flue gas waste heat utilization line for low-temperature calcination.

[0018] Further, a carbonation reaction device and a bicarbonate ammonia input line are further included, the calcination flue gas return line is connected to the low-temperature calcination device at one end and to the carbonation reaction device at the other end; the bicarbonate ammonia input line is connected to the carbonation reaction device at one end and to the synthesis reaction device at the other end.

[0019] In a second aspect, the application provides a method for regenerating and utilizing waste zinc oxide desulfurizer, using the system for regenerating and utilizing waste zinc oxide desulfurizer according to any one of the preceding aspects, including a high-temperature oxidative roasting step, a desulfurized slurry returning step, an acid leaching step, a synthesis reaction step, a low-temperature calcination step,

[0020] The high-temperature oxidative roasting step: oxidatively roasting the waste zinc oxide desulfurizer to obtain zinc suboxide material and flue gas; the flue gas is introduced into the flue gas dedusting device through the high-temperature flue gas discharge line for dedusting; the hot dedusted flue gas is introduced into the low-temperature calcination device through the dedusted flue gas waste heat utilization line after dedusting;

[0021] The desulfurization slurry returning step: part of the secondary zinc oxide material is mixed with water through the calcined material bypass line to generate secondary zinc oxide slurry into the desulfurization device; the calcined flue gas generated after the low-temperature calcination device calcines the solid phase basic zinc carbonate enters the desulfurization device through the calcined flue gas return line, and the dedusted flue gas enters the low-temperature calcination device through the dedusted flue gas waste heat utilization line to generate cold dedusted flue gas which enters the desulfurization device through the dedusted flue gas return line; the calcined flue gas and the cold dedusted flue gas are mixed to form a sulfur-containing mixed flue gas, and the secondary zinc oxide slurry reacts with the sulfur-containing mixed flue gas and air to generate desulfurization slurry and desulfurization mixed flue gas; the desulfurization slurry enters the acid leaching device through the desulfurization material return line;

[0022] The acid leaching step: another part of the secondary zinc oxide material, the desulfurization slurry and sulfuric acid are mixed to perform acid leaching treatment to obtain a zinc-containing leaching solution;

[0023] The synthesis reaction step: pure alkali is added to the zinc-containing leaching solution to perform synthesis reaction, and solid phase basic zinc carbonate is obtained after the reaction is completed;

[0024] The low-temperature calcination step: the solid phase basic zinc carbonate is dried and calcined by taking the waste heat of the hot dedusted flue gas as the heat source to obtain active zinc oxide, cold dedusted flue gas and calcined flue gas.

[0025] Further, in the high-temperature oxidation calcination step, the waste zinc oxide desulfurizer is subjected to staged oxidation calcination; the first stage oxidation calcination temperature ranges from 515 to 585°C; the second stage oxidation calcination temperature ranges from 610 to 749°C; and the third stage oxidation calcination temperature ranges from 750 to 900°C.

[0026] Further, in the desulfurization slurry returning step, the dedusted ash after dedusting by the flue gas dedusting device enters the desulfurization device through the dedusted ash conveying line, and part of the secondary zinc oxide material is mixed with water through the calcined material bypass line, and then mixed with the dedusted ash and water again to generate secondary zinc oxide slurry.

[0027] Further, in the acid leaching step, the sulfuric acid concentration at the end of the leaching is 95-120 g / L, and the pH value at the end of the leaching is 5.2-5.3.

[0028] Further, in the synthesis reaction step, the weight ratio of pure alkali to zinc-containing leaching solution is 0.3-0.5:1, and the synthesis reaction temperature is 63-82°C; the particle size of the obtained solid phase basic zinc carbonate ranges from 23 to 38 μm, and is spherical.

[0029] Further, in the low-temperature calcination step, the calcination temperature is 360-500°C, and the specific surface area of the active zinc oxide after calcination is 73-85 m 3 ·g -1The mass ratio of the secondary zinc oxide in the secondary zinc oxide slurry to water in the step of returning the desulfurization slurry is 0.1-0.2:1.

[0030] In a third aspect, the examples of the present application provide a method for recycling waste zinc oxide desulfurizer, using the recycling system for waste zinc oxide desulfurizer as described above, comprising a high-temperature oxidative roasting step, a desulfurization slurry returning step, an acid leaching step, a carbonization reaction step, a synthesis reaction step, a low-temperature calcination step,

[0031] The high-temperature oxidative roasting step: oxidatively roasting the waste zinc oxide desulfurizer to obtain secondary zinc oxide material and flue gas; the flue gas enters the flue gas dust removal device for dust removal through the high-temperature flue gas discharge line; the hot dust removal flue gas enters the low-temperature calcination device through the dust removal flue gas waste heat utilization line after dust removal;

[0032] The desulfurization slurry returning step: part of the secondary zinc oxide material is mixed with water to generate secondary zinc oxide slurry which enters the desulfurization device through the roasting material side branch line; the cold dust removal flue gas generated after the hot dust removal flue gas enters the low-temperature calcination device through the dust removal flue gas waste heat utilization line enters the desulfurization device through the dust removal flue gas return line; the secondary zinc oxide slurry reacts with the cold dust removal flue gas and air to generate desulfurization slurry and desulfurization mixed flue gas; the desulfurization slurry enters the acid leaching device through the desulfurization material return line;

[0033] The acid leaching step: another part of the secondary zinc oxide material and the desulfurization slurry are mixed with sulfuric acid for acid leaching treatment to obtain a zinc-containing leaching solution;

[0034] The carbonization reaction step: waste ammonia water is added to the carbonization reaction device to react with CO2 in the calcination flue gas to generate an ammonium bicarbonate solution;

[0035] The synthesis reaction step: the ammonium bicarbonate solution is input into the synthesis reaction device through the ammonium bicarbonate input line and mixed with the zinc-containing leaching solution for synthesis reaction; after the reaction is completed, a solid phase basic zinc carbonate is obtained;

[0036] The low-temperature calcination step: the solid phase basic zinc carbonate is dried and calcined using the waste heat of the hot dust removal flue gas as a heat source to obtain active zinc oxide, cold dust removal flue gas and calcination flue gas; the calcination flue gas enters the carbonization reaction device through the calcination flue gas return line.

[0037] The beneficial effects include:

[0038] By setting high-temperature flue gas discharge line, calcined material side branch line, desulfurized material return line, calcination flue gas return line, dust removal flue gas return line, dust removal flue gas waste heat utilization line and the like, the internal closed loop circulation of the oxidized calcination flue gas, the secondary oxidized zinc and the like between the high-temperature oxidized calcination device, the acid leaching device, the synthesis reaction device, the low-temperature calcination device, the flue gas dust removal device, the desulfurization device and the like is realized, the waste desulfurizer material is recycled as much as possible through the internal closed loop circulation, the regeneration rate can reach more than 98%, at the same time, the waste heat can be fully utilized to reduce the process energy consumption, reduce carbon emissions, save energy and reduce consumption, the secondary pollution caused by sulfur emissions in the waste desulfurizer regeneration process can be reduced, the utilization of sulfur resources is realized, the acid consumption is reduced, and the zinc loss is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0039] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0040] Figure 1 The regeneration and utilization system structure schematic diagram of the waste oxidized zinc desulfurizer provided by the embodiments of the present application.

[0041] Figure 2 The regeneration and utilization system structure schematic diagram of the waste oxidized zinc desulfurizer provided by another embodiment of the present application.

[0042] Figure: 1-high-temperature oxidized calcination device; 2-acid leaching device; 3-synthesis reaction device; 4-low-temperature calcination device; 5-flue gas dust removal device; 6-desulfurization device; 7-high-temperature flue gas discharge line; 8-calcined material side branch line; 9-desulfurized material return line; 10-calcination flue gas return line; 11-dust removal flue gas return line; 12-dust removal flue gas waste heat utilization line; 13-dust removal ash conveying line; 14-carbonization reaction device; 15-bicarbonate ammonia input line. DETAILED DESCRIPTION

[0043] The embodiments of the present application will be described in detail below in combination with the embodiments, but those skilled in the art will understand that the following embodiments are only used to illustrate the present application, and should not be regarded as limiting the scope of the present application. The specific conditions are not specified in the embodiments, and are carried out according to the conventional conditions or the conditions recommended by the manufacturer. The reagents or instruments used are not specified by the manufacturer, and are conventional products that can be purchased on the market.

[0044] The zinc oxide desulfurizer is converted into ZnS after desulfurization, and loses activity to become waste zinc oxide desulfurizer. The waste zinc oxide desulfurizer is converted into active zinc oxide by the regeneration and utilization system and the regeneration and utilization method of the waste zinc oxide desulfurizer.

[0045] The regeneration and utilization system and the regeneration and utilization method of the waste zinc oxide desulfurizer of the embodiments of the present application are described below in combination with Figures 1-2 The embodiments are described in detail.

[0046] In the first aspect, the embodiments of the present application provide a regeneration and utilization system of waste zinc oxide desulfurizer (see Figure 1 ), comprising a high-temperature oxidation roasting device 1, an acid leaching device 2, a synthesis reaction device 3, a low-temperature calcination device 4, and further comprising a flue gas dust removal device 5, a desulfurization device 6, a high-temperature flue gas discharge line 7, a roasting material bypass line 8, a desulfurization material return line 9, a calcination flue gas return line 10, a dust removal flue gas return line 11, a dust removal flue gas waste heat utilization line 12, and a dust removal ash conveying line 13.

[0047] One end of the high-temperature flue gas discharge line 7 is connected to the high-temperature oxidation roasting device 1, and the other end is connected to the flue gas dust removal device 5.

[0048] One end of the roasting material bypass line 8 is connected to the material output line of the high-temperature oxidation roasting device 1, and the other end is connected to the desulfurization device 6.

[0049] One end of the desulfurization material return line 9 is connected to the acid leaching device 2, and the other end is connected to the desulfurization device 6.

[0050] One end of the calcination flue gas return line 10 is connected to the low-temperature calcination device 4, and the other end is connected to the desulfurization device 6.

[0051] One end of the dust removal flue gas return line 11 is connected to the low-temperature calcination device 4, and the other end is connected to the desulfurization device 6.

[0052] One end of the dust removal flue gas waste heat utilization line 12 is connected to the flue gas dust removal device 5, and the other end is connected to the low-temperature calcination device 4.

[0053] One end of the dust removal ash conveying line 13 is connected to the flue gas dust removal device 5, and the other end is connected to the desulfurization device 6.

[0054] The high-temperature oxidative roasting device 1, the acid leaching device 2, the synthesis reaction device 3, the low-temperature calcining device 4, the flue gas dust removal device 5, the desulfurization device 6 and the like are not specifically limited, and the existing devices in the field that can realize high-temperature oxidative roasting, acid leaching device, synthesis reaction, low-temperature calcining, flue gas dust removal, desulfurization of slurry and gas mixing and the like can be used. For example, the high-temperature oxidative roasting device 1 can be a rotary kiln, a rotary hearth furnace, a tunnel kiln and the like; and the low-temperature calcining device 4 can be a rotary kiln, a rotary hearth furnace, a tunnel kiln and the like. After the material enters the high-temperature oxidative roasting device 1, it is sequentially conveyed into the acid leaching device 2, the synthesis reaction device 3 and the low-temperature calcining device 4 by a conventional conveying method, and the specific description is not given herein, and the material conveying can be realized.

[0055] By arranging the high-temperature flue gas discharge line 7, the roasting material bypass line 8, the desulfurized material return line 9, the calcining flue gas return line 10, the dust removal flue gas return line 11, the dust removal flue gas waste heat utilization line 12 and the dust removal dust conveying line 13, the internal closed loop circulation of the oxidative roasting flue gas, the secondary zinc oxide and the like between the high-temperature oxidative roasting device 1, the acid leaching device 2, the synthesis reaction device 3, the low-temperature calcining device 4, the flue gas dust removal device 5 and the desulfurization device 6 is realized, the waste desulfurizer material is recycled as much as possible through the internal closed loop circulation, the regeneration rate can reach more than 98%, the waste heat can be fully utilized to reduce the process energy consumption, reduce carbon emissions, save energy and reduce consumption, the secondary pollution caused by the waste desulfurizer regeneration process can be reduced, the sulfur resource utilization is realized, the acid consumption is reduced, and the zinc loss is reduced.

[0056] The low-temperature calcining device 4 comprises a radiation pipe, and the hot dust removal flue gas is introduced into the radiation pipe through the dust removal flue gas waste heat utilization line 12 for low-temperature calcining of the solid phase basic zinc carbonate. The calcined flue gas flows into the desulfurization device 6 through the calcining flue gas return line 10, the radiation pipe radiation heating method is used for calcining the basic zinc carbonate, the reaction of SO2 in the flue gas with the zinc oxide material can be avoided to affect the activity of the zinc oxide, and the process waste heat can be fully utilized to reduce the process energy consumption and reduce carbon dioxide emissions.

[0057] In the second aspect, the application provides a regeneration and utilization method of waste zinc oxide desulfurizer, using the regeneration and utilization system of waste zinc oxide desulfurizer as described above, comprising a high-temperature oxidative roasting step, a desulfurized slurry return step, an acid leaching step, a synthesis reaction step, a low-temperature calcining step,

[0058] The high-temperature oxidative roasting step: the waste zinc oxide desulfurizer is subjected to oxidative roasting through the high-temperature oxidative roasting device 1, the oxidative roasting temperature is 515-900°C, the secondary zinc oxide material (also known as crude zinc oxide, the main component is ZnO) and flue gas are obtained; the flue gas is introduced into the flue gas dust removal device 5 through the high-temperature flue gas discharge line 7 for dust removal; and the hot dust removal flue gas after dust removal is introduced into the low-temperature calcining device 4 through the dust removal flue gas waste heat utilization line 12.

[0059] Optionally, the waste zinc oxide desulfurizer is subjected to staged and sequential temperature rising in the high-temperature oxidation roasting step. The oxidation roasting time of the first stage, the second stage and the third stage can be distributed according to the total process time, which is not limited herein, and can be exemplarily as follows: the first stage time accounts for 30-40% of the total time, the second stage time accounts for 40-50% of the total time, and the third stage time accounts for 10-20% of the total time.

[0060] The first stage oxidation roasting temperature ranges from 515-585℃ (exemplarily as 515℃, 523℃, 531℃, 542℃, 556℃, 563℃, 576℃, 585℃, etc.); in this stage, ZnS is mainly oxidized to ZnSO4. Through the low-temperature oxidation roasting in this stage, Zn loss can be reduced, and the generation of SO2 in the subsequent oxidation process can be promoted.

[0061] The second stage oxidation roasting temperature ranges from 610-749℃ (exemplarily as 610℃, 621℃, 634℃, 645℃, 656℃, 663℃, 673℃, 685℃, 697℃, 706℃, 712℃, 723℃, 736℃, 749℃, etc.); in this stage, in addition to the oxidation of ZnS to ZnSO4, the reaction of ZnS and ZnSO4 to generate ZnO and SO2 also occurs. Through the control of this stage, part of the secondary zinc oxide material can be reacted with SO2 and oxygen to generate ZnSO4, thereby realizing the utilization value of the flue gas and accelerating the reaction process and improving the efficiency.

[0062] The third stage oxidation roasting temperature ranges from 750-900℃ (750℃, 765℃, 778℃, 786℃, 795℃, 802℃, 813℃, 834℃, 846℃, 857℃, 863℃, 879℃, 882℃, 896℃, 900℃, etc.). This stage can improve the production efficiency of generating ZnO, and at the same time, part of SO3 is generated, which can be used to generate sulfuric acid in the desulfurization device, thereby reducing the amount of acid used in acid leaching. The oxidation roasting temperature and time of the first stage, the second stage and the third stage can be adjusted according to the PH value in the acid leaching step to realize less acid amount used in acid leaching.

[0063] The desulfurized slurry returning step: part of the secondary zinc oxide material is mixed with water through the roasting material side branch line 8 to generate secondary zinc oxide slurry into the desulfurization device 6; the calcined flue gas generated after the low-temperature calcination device 4 calcines the solid basic zinc carbonate enters the desulfurization device 6 through the calcined flue gas return line 10; the hot dedusting flue gas enters the low-temperature calcination device 4 through the dedusting flue gas waste heat utilization line 12 to generate cold dedusting flue gas which enters the desulfurization device 6 through the dedusting flue gas return line 11; the calcined flue gas and the cold dedusting flue gas are mixed to form a sulfur-containing mixed flue gas; the secondary zinc oxide slurry reacts with the sulfur-containing mixed flue gas and air to generate desulfurized slurry and desulfurized mixed flue gas; the desulfurized slurry enters the acid leaching device 2 through the desulfurized material return line 9.

[0064] In the desulfurization device, the sulfur-containing mixed flue gas is desulfurized by using the zinc oxide in the secondary zinc oxide slurry to react with sulfur dioxide in the flue gas to generate zinc sulfite, and the zinc sulfite reacts with oxygen in the air to generate zinc sulfate, so that the flue gas meets the emission standard, the desulfurization slurry is returned to the system, and no desulfurization waste residue is discharged.

[0065] Reaction formula: ZnO + SO2 = ZnSO3 2ZnSO3 + O2 = 2ZnSO4.

[0066] Optionally, in the desulfurization slurry returning step, the dust removal ash after the flue gas dust removal device 5 is removed is introduced into the desulfurization device 6 through the dust removal ash conveying line 13, and part of the secondary zinc oxide material is mixed with water through the calcined material side branch line 8, and then mixed with the dust removal ash and water again to generate the secondary zinc oxide slurry. The mass ratio of the secondary zinc oxide to water in the secondary zinc oxide slurry in the desulfurization slurry returning step is 0.1-0.2:1. The above-mentioned ratio can improve the acid leaching efficiency and reduce the amount of acid used.

[0067] Acid leaching step: another part of the secondary zinc oxide material, the desulfurization slurry and sulfuric acid are mixed, and acid leaching treatment is performed in the acid leaching device 2 to obtain a zinc-containing leaching solution. In the acid leaching step, the sulfuric acid concentration at the end of the acid leaching is 95-120 g / L (for example: 95 g / L, 97 g / L, 99 g / L, 103 g / L, 107 g / L, 113 g / L, 115 g / L, 117 g / L, 119 g / L, 120 g / L, etc.), the pH value at the end of the leaching is 5.2-5.3, a zinc-containing leaching solution (zinc sulfate purification solution) is obtained, and the acid leaching temperature is 91-98°C. By controlling the higher acid leaching temperature, the lower sulfuric acid concentration and the lower pH value at the end of the leaching, the acid leaching efficiency can be improved, and the amount of acid used can be reduced.

[0068] By using the above-mentioned desulfurization slurry returning, that is, by performing acid leaching through two routes of direct and indirect of the two parts of the secondary zinc oxide material, the system temperature can be improved, the synthesis efficiency can be improved, and the amount of acid used can be reduced.

[0069] Synthesis reaction step: in the synthesis reaction device 3, pure alkali is added to the zinc-containing leaching solution for synthesis reaction, and after the reaction is completed, a solid phase basic zinc carbonate is obtained.

[0070] The reaction principle is:

[0071] The reaction principle is:

[0072] Reaction formula: 3ZnSO4 + 3Na2CO3 + 3H2O = Zn2(OH)2CO3 + 3Na2SO4 + 2CO2

[0073] The weight ratio of soda ash to zinc-containing leaching solution in the synthesis reaction step is 0.3-0.5:1 (for example: 0.3:1, 0.4:1, 0.5:1, etc.), and the synthesis reaction temperature is 63-82°C (for example: 63°C, 64°C, 66°C, 68°C, 71°C, 74°C, 77°C, 79°C, 81°C, 82°C, etc.). If the synthesis reaction temperature is higher than the above range, the particle size of the solid basic zinc carbonate obtained is too large, and if it is lower than the above range, the particle size of the solid basic zinc carbonate obtained is too small. The particle size of the solid basic zinc carbonate obtained is in the range of 23-38 μm (for example: 23 μm, 26 μm, 29 μm, 31 μm, 33 μm, 34 μm, 36 μm, 37 μm, 38 μm, etc.), and it is spherical. If the particle size is larger than the above range, the specific surface area is small, and the specific surface area of the calcined zinc oxide is reduced. If the particle size is smaller than the above range, the calcination process is prone to agglomeration, and the specific surface area of the calcined zinc oxide is reduced.

[0074] Low-temperature calcination step: The solid basic zinc carbonate after rinsing is dried and calcined in a low-temperature calcination device using the waste heat of the hot dedusting flue gas as the heat source, to obtain active zinc oxide, cold dedusting flue gas, and calcination flue gas.

[0075] Reaction formula: Zn2(OH)2CO3 = 2ZnO + CO2 + H2O.

[0076] In the low-temperature calcination step, the calcination temperature is 360-500°C (for example: 360°C, 382°C, 393°C, 423°C, 446°C, 465°C, 478°C, 487°C, 493°C, 500°C, etc.). If the temperature is higher than the above range, the zinc oxide is prone to agglomeration, and the specific surface area is reduced. If the temperature is lower than the above range, the specific surface area is low, and the decomposition is not sufficient, and the proportion of zinc oxide is less than 90%. The specific surface area of the active zinc oxide after calcination is 73-85 m 3 ·g -1 (for example: 73 m 3 ·g -1 , 75 m 3 ·g -1 , 77 m 3 ·g -1 , 79 m 3 ·g -1 , 81 m 3 ·g -1 , 83 m 3 ·g -1 , 85 m 3 ·g -1 , etc.).

[0077] In some embodiments, the carbonization reaction device 14 and the ammonium bicarbonate input line 15 are further included, one end of the calcination flue gas return line 10 is connected to the low-temperature calcination device 4, and the other end is connected to the carbonization reaction device 14; one end of the ammonium bicarbonate input line 15 is connected to the carbonization reaction device 14, and the other end is connected to the synthesis reaction device 3 (see Figure 2 ).

[0078] The carbonization reaction device 14 and the ammonium bicarbonate input line 15 are added, the calcination flue gas enters the carbonization reaction device 14 through the calcination flue gas return line 10, waste ammonia water is added to the carbonization reaction device 14 to react with CO2 in the calcination flue gas to generate ammonium bicarbonate solution; the ammonium bicarbonate solution is input through the ammonium bicarbonate input line 15 to mix with the zinc-containing leaching solution for a synthesis reaction, and solid basic zinc carbonate is obtained after the reaction is completed. This method can more fully utilize CO2 and other substances in the calcination flue gas, make it react with waste ammonia water to generate ammonium bicarbonate solution, so as to obtain lye for a synthesis reaction with the zinc-containing leaching solution, further reduce external substances, reduce carbon emissions, and further reduce costs.

[0079] The features and performance of the present application are further described in detail below in conjunction with embodiments:

[0080] Example 1

[0081] A regeneration and utilization method of waste zinc oxide desulfurizer,

[0082] High-temperature oxidation roasting step: the first-stage oxidation roasting temperature is 576℃; the second-stage oxidation roasting temperature is 723℃; and the third-stage oxidation roasting temperature ranges from 863℃.

[0083] Desulfurization slurry return step: the mass ratio of parazinc to water in the parazinc slurry is 0.1-0.2:1.

[0084] Acid leaching step: the acid leaching end-point sulfuric acid concentration in the acid leaching step is 107g / L, the leaching end-point pH value is 5.2, and the acid leaching temperature is 97℃.

[0085] Synthesis reaction step: the weight ratio of soda ash to zinc-containing leaching solution is 0.4:1, the synthesis reaction temperature is 72℃; and the particle size range of the obtained solid basic zinc carbonate is 24-30μm.

[0086] Low-temperature calcination step: the calcination temperature is 465℃, and the specific surface area of the active zinc oxide after calcination is 82m 3 ·g -1 .

[0087] Example 2

[0088] The process parameters are substantially the same as those of Example 1, except that the synthesis reaction temperature is 81℃; the particle size range of the solid-phase basic zinc carbonate obtained is 31-38μm; and the specific surface area of the active zinc oxide after calcination is 74m 3 ·g -1 .

[0089] Example 3

[0090] The process parameters are substantially the same as those of Example 1, except that the synthesis reaction temperature is 65℃; the particle size range of the solid-phase basic zinc carbonate obtained is 23-25μm; and the specific surface area of the active zinc oxide after calcination is 76m 3 ·g -1 .

[0091] Example 4

[0092] The process parameters are substantially the same as those of Example 1, except that the low-temperature calcination step: the calcination temperature is 376℃, and the specific surface area of the active zinc oxide after calcination is 75m 3 ·g -1 .

[0093] Example 5

[0094] The process parameters are substantially the same as those of Example 1, except that the low-temperature calcination step: the calcination temperature is 491℃, and the specific surface area of the active zinc oxide after calcination is 79m 3 ·g -1 .

[0095] Example 6

[0096] A method for regenerating and utilizing a waste zinc oxide desulfurizer,

[0097] The high-temperature oxidation calcination step:

[0098] The first-stage oxidation calcination temperature ranges from 545℃; the second-stage oxidation calcination temperature ranges from 689℃; and the third-stage oxidation calcination temperature ranges from 832℃.

[0099] The desulfurization slurry returning step: the mass ratio of the secondary zinc oxide to water in the secondary zinc oxide slurry is 0.2:1.

[0100] The acid leaching step: the sulfuric acid concentration at the leaching end point is 110g / L, and the pH value at the leaching end point is 5.3.

[0101] The synthesis reaction step: the weight ratio of the pure alkali to the zinc-containing leaching solution is 0.3:1, and the synthesis reaction temperature is 72℃; the particle size range of the solid-phase basic zinc carbonate obtained is 25-34μm, and the shape is spherical.

[0102] The low-temperature calcination step: the calcination temperature is 421℃, and the specific surface area of the active zinc oxide after calcination is 75m 3·g -1 .

[0103] Example 7

[0104] A method for regeneration and utilization of waste zinc oxide desulfurizer,

[0105] High-temperature oxidative roasting step:

[0106] The first-stage oxidative roasting temperature range is 553°C; the second-stage oxidative roasting temperature range is 649°C; and the third-stage oxidative roasting temperature range is 813°C.

[0107] Desulfurized slurry returning step: the mass ratio of zinc suboxide to water in the zinc suboxide slurry is 0.1:1.

[0108] Acid leaching step: the sulfuric acid concentration at the leaching end point is 98 g / L, and the pH value at the leaching end point is 5.3.

[0109] Synthesis reaction step: the weight ratio of soda ash to the zinc-containing leaching solution is 0.5:1, and the synthesis reaction temperature is 88°C; the particle size range of the solid-phase basic zinc carbonate obtained is 39-43 μm.

[0110] Low-temperature calcination step: the calcination temperature is 431°C, and the specific surface area of the active zinc oxide after calcination is 61 m 3 ·g -1 .

[0111] Example 8

[0112] A method for regeneration and utilization of waste zinc oxide desulfurizer,

[0113] High-temperature oxidative roasting step:

[0114] The first-stage oxidative roasting temperature range is 543°C; the second-stage oxidative roasting temperature range is 661°C; and the third-stage oxidative roasting temperature range is 823°C.

[0115] Desulfurized slurry returning step: the mass ratio of zinc suboxide to water in the zinc suboxide slurry is 0.1:1.

[0116] Acid leaching step: the sulfuric acid concentration at the leaching end point is 103 g / L, and the pH value at the leaching end point is 5.3.

[0117] Synthesis reaction step: the weight ratio of soda ash to the zinc-containing leaching solution is 0.4:1, and the synthesis reaction temperature is 45°C; the particle size range of the solid-phase basic zinc carbonate obtained is 11-21 μm.

[0118] Low-temperature calcination step: the calcination temperature is 429°C, and the specific surface area of the active zinc oxide after calcination is 59 m 3 ·g -1 .

[0119] Example 9

[0120] A method for regeneration and utilization of waste zinc oxide desulfurizer,

[0121] High-temperature oxidative roasting step:

[0122] The first-stage oxidative roasting temperature range is 566℃; the second-stage oxidative roasting temperature range is 628℃; and the third-stage oxidative roasting temperature range is 795℃.

[0123] Desulfurization slurry returning step: the mass ratio of zinc suboxide to water in the zinc suboxide slurry is 0.1:1.

[0124] Acid leaching step: the sulfuric acid concentration at the leaching end point is 114g / L, and the pH value at the leaching end point is 5.3.

[0125] Synthesis reaction step: the weight ratio of soda ash to the zinc-containing leaching solution is 0.5:1, and the synthesis reaction temperature is 77℃; the particle size range of the solid-phase basic zinc carbonate obtained is 22-26μm, and the shape is spherical.

[0126] Low-temperature calcination step: the calcination temperature is 340℃, and the specific surface area of the active zinc oxide after calcination is 62m 3 ·g -1 .

[0127] Example 10

[0128] A method for regeneration and utilization of waste zinc oxide desulfurizer,

[0129] High-temperature oxidative roasting step:

[0130] The first-stage oxidative roasting temperature range is 573℃; the second-stage oxidative roasting temperature range is 633℃; and the third-stage oxidative roasting temperature range is 786℃.

[0131] Desulfurization slurry returning step: the mass ratio of zinc suboxide to water in the zinc suboxide slurry is 0.1:1.

[0132] Acid leaching step: the sulfuric acid concentration at the leaching end point is 116g / L, and the pH value at the leaching end point is 5.2.

[0133] Synthesis reaction step: the weight ratio of soda ash to the zinc-containing leaching solution is 0.4:1, and the synthesis reaction temperature is 75℃; the particle size range of the solid-phase basic zinc carbonate obtained is 22-26μm, and the shape is spherical.

[0134] Low-temperature calcination step: the calcination temperature is 514℃, and the specific surface area of the active zinc oxide after calcination is 46m 3 ·g -1 .

[0135] The above descriptions are only specific embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for regenerating waste zinc oxide desulfurizing agent, comprising a waste zinc oxide desulfurizing agent regeneration system, characterized in that, The waste zinc oxide desulfurizing agent recycling system includes a high-temperature oxidation roasting device, an acid leaching device, a synthesis reaction device, a low-temperature calcination device, and also includes a flue gas dust removal device, a desulfurization device, a high-temperature flue gas discharge line, a roasting material side branch line, a desulfurization material return line, a calcination flue gas return line, a dust removal flue gas return line, and a dust removal flue gas waste heat utilization line. One end of the high-temperature flue gas discharge line is connected to the high-temperature oxidation roasting device, and the other end is connected to the flue gas dust removal device. One end of the side branch line of the roasting material is connected to the material output line of the high-temperature oxidation roasting device, and the other end is connected to the desulfurization device. One end of the desulfurized material return line is connected to the acid leaching device, and the other end is connected to the desulfurization device; One end of the calcination flue gas return line is connected to the low-temperature calcination device, and the other end is connected to the desulfurization device; One end of the dust removal flue gas return line is connected to the low-temperature calcination device, and the other end is connected to the desulfurization device; One end of the waste heat utilization line for dust removal flue gas is connected to the flue gas dust removal device, and the other end is connected to the low-temperature calcination device. The recycling method includes a high-temperature oxidation roasting step, a desulfurization slurry return step, an acid leaching step, a synthesis reaction step, and a low-temperature calcination step. The high-temperature oxidation roasting step involves oxidizing and roasting the waste zinc oxide desulfurizer to obtain secondary zinc oxide material and flue gas; the flue gas enters the flue gas dust removal device through the high-temperature flue gas discharge line for dust removal; the hot dust removal flue gas after dust removal is introduced into the low-temperature calcination device through the dust removal flue gas waste heat utilization line. The desulfurization slurry return step involves the following steps: A portion of the secondary zinc oxide material is mixed with water via the calcination material bypass line to generate a secondary zinc oxide slurry, which then enters the desulfurization unit. The calcination flue gas generated after calcining solid-phase basic zinc carbonate in the low-temperature calcination unit enters the desulfurization unit via the calcination flue gas return line. The hot dust removal flue gas is passed through the dust removal flue gas waste heat utilization line into the low-temperature calcination unit, generating cold dust removal flue gas, which then enters the desulfurization unit via the dust removal flue gas return line. The calcination flue gas and cold dust removal flue gas mix to form a sulfur-containing mixed flue gas. The secondary zinc oxide slurry reacts with the sulfur-containing mixed flue gas and air to generate a desulfurization slurry and a desulfurization mixed flue gas. The desulfurization slurry then enters the acid leaching unit via the desulfurization material return line. The acid leaching step involves mixing another portion of zinc oxide material and desulfurization slurry with sulfuric acid to obtain a zinc-containing leachate. The synthesis reaction step is as follows: soda ash is added to the zinc-containing leaching solution to carry out the synthesis reaction, and solid-phase basic zinc carbonate is obtained after the reaction is completed. The low-temperature calcination step involves drying and calcining the solid-phase basic zinc carbonate using the residual heat of the hot dust removal flue gas as a heat source to obtain active zinc oxide, cold dust removal flue gas, and calcination flue gas. The high-temperature oxidation roasting step involves staged oxidation roasting of the waste zinc oxide desulfurizer; the first stage oxidation roasting temperature ranges from 515 to 585℃; the second stage oxidation roasting temperature ranges from 610 to 749℃; and the third stage oxidation roasting temperature ranges from 750 to 900℃; the first stage accounts for 30-40% of the total time, the second stage accounts for 40-50% of the total time, and the third stage accounts for 10-20% of the total time.

2. The method for regenerating waste zinc oxide desulfurizing agent according to claim 1, characterized in that, It also includes a dust removal ash conveying line, one end of which is connected to the flue gas dust removal device and the other end of which is connected to the desulfurization device; the low-temperature calcination device includes a radiant tube, and the hot dust removal flue gas is introduced into the radiant tube through the dust removal flue gas waste heat utilization line for low-temperature calcination.

3. The method for regenerating waste zinc oxide desulfurizing agent according to claim 2, characterized in that, The desulfurization slurry return step also includes the dust removed by the flue gas dust removal device entering the desulfurization device through the dust removal ash conveyor line, and some secondary zinc oxide material being mixed with water through the roasting material side branch line, and then further mixed with dust removal ash and water to generate secondary zinc oxide slurry.

4. The method for regenerating and utilizing waste zinc oxide desulfurizing agent according to claim 1, characterized in that, The acid leaching step has a sulfuric acid concentration of 95–120 g / L at the leaching endpoint and a pH value of 5.2–5.3 at the leaching endpoint.

5. The method for regenerating waste zinc oxide desulfurizing agent according to claim 1, characterized in that, In the synthesis reaction step, the weight ratio of soda ash to zinc-containing leaching solution is 0.3 to 0.5:1, and the synthesis reaction temperature is 63-82℃; the particle size range of the obtained solid-phase basic zinc carbonate is 23-38μm, and it is spherical.

6. The method for regenerating waste zinc oxide desulfurizing agent according to claim 1, characterized in that, In the low-temperature calcination step, the calcination temperature is 360-500℃, and the specific surface area of ​​the active zinc oxide after calcination is 73-85 m². 3 ·g -1 In the desulfurization slurry return step, the mass ratio of zinc oxide to water in the zinc oxide slurry is 0.1 to 0.2:

1.

7. A method for regenerating waste zinc oxide desulfurizing agent, comprising a waste zinc oxide desulfurizing agent regeneration system, characterized in that, The waste zinc oxide desulfurizing agent recycling system includes a high-temperature oxidation roasting device, an acid leaching device, a synthesis reaction device, a low-temperature calcination device, and also includes a flue gas dust removal device, a desulfurization device, a high-temperature flue gas discharge line, a roasting material side branch line, a desulfurization material return line, a calcination flue gas return line, a dust removal flue gas return line, and a dust removal flue gas waste heat utilization line. One end of the high-temperature flue gas discharge line is connected to the high-temperature oxidation roasting device, and the other end is connected to the flue gas dust removal device. One end of the side branch line of the roasting material is connected to the material output line of the high-temperature oxidation roasting device, and the other end is connected to the desulfurization device. One end of the desulfurized material return line is connected to the acid leaching device, and the other end is connected to the desulfurization device; One end of the calcination flue gas return line is connected to the low-temperature calcination device, and the other end is connected to the desulfurization device; One end of the dust removal flue gas return line is connected to the low-temperature calcination device, and the other end is connected to the desulfurization device; The waste heat utilization line for dust removal flue gas is connected at one end to the flue gas dust removal device and at the other end to the low-temperature calcination device; it also includes a carbonization reaction device and an ammonium bicarbonate input line, the calcination flue gas return line is connected at one end to the low-temperature calcination device and at the other end to the carbonization reaction device; the ammonium bicarbonate input line is connected at one end to the carbonization reaction device and at the other end to the synthesis reaction device. The recycling method includes a high-temperature oxidation roasting step, a desulfurization slurry return step, an acid leaching step, a carbonization reaction step, a synthesis reaction step, and a low-temperature calcination step. The high-temperature oxidation roasting step involves oxidizing and roasting the waste zinc oxide desulfurizer to obtain secondary zinc oxide material and flue gas; the flue gas enters the flue gas dust removal device through the high-temperature flue gas discharge line for dust removal; the hot dust removal flue gas after dust removal is introduced into the low-temperature calcination device through the dust removal flue gas waste heat utilization line. The desulfurization slurry return step is as follows: a portion of the secondary zinc oxide material is mixed with water through the calcination material bypass line to generate secondary zinc oxide slurry, which then enters the desulfurization unit; hot dust removal flue gas is passed through the dust removal flue gas waste heat utilization line into the low-temperature calcination unit to generate cold dust removal flue gas, which then enters the desulfurization unit through the dust removal flue gas return line; the secondary zinc oxide slurry reacts with the cold dust removal flue gas and air to generate desulfurization slurry and desulfurization mixed flue gas; the desulfurization slurry enters the acid leaching unit through the desulfurization material return line. The acid leaching step involves mixing another portion of zinc oxide material and desulfurization slurry with sulfuric acid to obtain a zinc-containing leachate. The carbonization reaction step involves adding waste ammonia water to the carbonization reaction device to react with CO2 in the calcination flue gas to generate ammonium bicarbonate solution. The synthesis reaction step is as follows: the ammonium bicarbonate solution is fed into the zinc-containing leaching solution through the ammonium bicarbonate input line to carry out the synthesis reaction, and solid-phase basic zinc carbonate is obtained after the reaction is completed. The low-temperature calcination step involves drying and calcining the solid-phase basic zinc carbonate using the waste heat from the thermal dust removal flue gas as a heat source to obtain active zinc oxide, cold dust removal flue gas, and calcination flue gas. The calcination flue gas then enters the carbonization reaction device through the calcination flue gas return line. The high-temperature oxidation roasting step involves staged oxidation roasting of the waste zinc oxide desulfurizer. The first stage oxidation roasting temperature range is 515-585℃; the second stage oxidation roasting temperature range is 610-749℃; and the third stage oxidation roasting temperature range is 750-900℃. The first stage accounts for 30-40% of the total time, the second stage accounts for 40-50% of the total time, and the third stage accounts for 10-20% of the total time.

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