Harmless treatment method for dangerous solid waste in firework and cracker production

Abstract

The invention discloses an innocent treatment method of dangerous solid waste in firework and cracker production, which comprises the following steps: adding acid into the precipitated dangerous solid waste in firework and cracker production to control the pH value to be less than or equal to 3, stirring to react, adding alkali to control the alkali mass fraction to be 1-20%, stirring to react, adding an oxidizing agent and a catalyst to react, and finally filtering to obtain filter residue and filtrate, filter residues are harmless residues, and filtrate is discharged after reaching the standard. According to the method, combustion treatment and toxic extraction agent treatment are not needed, multiple hazardous wastes can be subjected to innocent treatment at the same time, the treatment cost is low, and the safety is high.

Description

Technical Field

[0001] The invention belongs to the technical field of hazardous solid waste treatment, and relates to a harmless treatment method for hazardous solid waste in the production of fireworks and firecrackers. Background Art

[0002] In the production process of fireworks and firecrackers, some scattered or discarded gunpowder and other hazardous solid wastes are generated, mainly containing sulfur, various metal powders (aluminum powder, magnesium powder, silver powder, etc.), nitrates, chlorates, perchlorates, etc. This type of hazardous solid waste is flammable and explosive, and also contains various heavy metals and other pollutants.

[0003] The existing treatment method mainly uses water washing and then sedimentation in a three-stage sedimentation tank, but it still produces a large amount of insoluble slag (mainly sulfur, metal powder, insoluble salt, etc.). There is currently almost no good treatment solution for this type of hazardous solid waste.

[0004] Chinese patent document CN106269816A discloses a device for treating waste drugs produced by the production of fireworks and firecrackers, which is destroyed by incineration, but there are problems such as mechanical collision and crushing of gunpowder and improper control of gunpowder feed, and there may also be safety problems such as explosion. Chinese patent document CN115520837A discloses a sulfur recovery system and method from hazardous wastes of fireworks and firecrackers, which uses the characteristic that sulfur dissolves in carbon disulfide to develop a recovery system and method, and uses water to cover and maintain the whole process. Then, the process only processes sulfur and requires the use of a large amount of highly toxic carbon disulfide, which has extremely high requirements for equipment.

[0005] In summary, there is an urgent need to develop a safe and low-cost harmless treatment process for this type of hazardous solid waste. Summary of the invention

[0006] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a method for harmlessly treating hazardous solid waste in the production of fireworks and firecrackers that does not require combustion treatment, does not require toxic extractant treatment, can simultaneously treat multiple hazardous wastes harmlessly, has low treatment cost and high safety.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions.

[0008] A method for harmlessly treating hazardous solid waste in the production of fireworks and firecrackers comprises the following steps: (1) Acid dissolution: Add water to the hazardous solid waste generated by fireworks and firecrackers production and stir, then add acid to control the pH value to ≤3, and after stirring and reaction, obtain acid-dissolved slurry; (2) Alkali dissolution: adding alkali to the acid-dissolved slurry, controlling the mass fraction of alkali in the obtained slurry to be 1% to 20%, stirring and reacting at 40°C to 80°C to obtain an alkali-dissolved slurry; (3) Oxidation: adding an oxidant and a catalyst to the alkali-dissolved slurry to carry out a redox reaction under stirring; (4) Filtration: The material obtained by the above oxidation is filtered to obtain filter residue and filtrate. The filter residue is harmless and the filtrate meets the discharge standards.

[0009] In the above-mentioned method for harmlessly treating hazardous solid waste in the production of fireworks and firecrackers, preferably, in step (1), the acid is sulfuric acid or hydrochloric acid, and the stirring reaction time is 0.5h to 2h.

[0010] In the above-mentioned method for harmlessly treating hazardous solid waste in the production of fireworks and firecrackers, preferably, in step (2), the alkali is one or more of sodium hydroxide, potassium hydroxide and barium hydroxide, and the stirring reaction time is 0.5h to 4h.

[0011] In the above-mentioned method for harmlessly treating hazardous solid waste in the production of fireworks and firecrackers, preferably, in step (3), the oxidant is one or more of hydrogen peroxide, ozone, hypochlorite, chlorate, permanganate and persulfate, and the amount of the oxidant is 1 to 4 times the theoretical amount of the redox reaction; the catalyst is one or more of iron salt, ferrous salt and cupric salt, and the amount of the catalyst in the slurry after alkali dissolution is 0.1 g / L to 10 g / L.

[0012] In the above-mentioned method for harmlessly treating hazardous solid waste in the production of fireworks and firecrackers, preferably, in step (3), the time of the redox reaction is 0.5h to 4h.

[0013] In the above-mentioned method for harmlessly treating hazardous solid wastes in the production of fireworks and firecrackers, preferably, in step (4), the filtrate is discharged after adjusting the pH value to 6 to 9 and meeting the discharge standards.

[0014] The main innovative features of the present invention are: The present invention uses acid dissolution, alkali dissolution and oxidation to treat hazardous solid wastes in the production of fireworks and firecrackers. The selection of reaction process, the design of reaction sequence and the limitation of relevant conditions in the reaction have an important influence on the treatment effect, the simplicity of the scheme and the cost control. The present invention designs acid dissolution, alkali dissolution and oxidation processes. Acid dissolution is first used to dissolve metal powders such as magnesium powder to make the metal powder in the slag react, which can avoid the violent reaction of metal powder and oxidant when oxidation is used later. Then, sulfur is dissolved by alkali dissolution, and the precipitated metal ions are neutralized at the same time. Then, oxidation treatment is used to oxidize the S generated in the alkali dissolution process. 2- and SO3 2- , making the sulfur harmless. If the order of alkali dissolution and oxidation is reversed, it will be difficult to handle the sulfur, because it was found during the research process that sulfur is difficult to oxidize directly, but is easier to dissolve in alkali.

[0015] Compared with the prior art, the advantages of the present invention are: 1) The method of the present invention does not require combustion treatment, does not require the addition of highly toxic extractants, etc., and the process is simple and safe; 2) Various pollutants and dangerous chemicals such as metal powder and sulfur in hazardous waste residues can be rendered harmless; 3) The equipment and auxiliary materials are common equipment and medicines, and the processing cost is low; 4) After treatment, the obtained filter residue is ordinary solid waste, which is not flammable and explosive, and the obtained filtrate can meet the emission standards. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic flow chart of the method for harmlessly treating hazardous solid waste in the production of fireworks and firecrackers in Example 1 of the present invention. DETAILED DESCRIPTION

[0017] The present invention is further described below in conjunction with the accompanying drawings and specific preferred embodiments, but the protection scope of the present invention is not limited thereby. The materials and instruments used in the following embodiments are all commercially available.

[0018] Example 1 A harmless treatment method for hazardous solid waste in the production of fireworks and firecrackers of the present invention, the hazardous solid waste raw material is the waste residue of the tertiary sedimentation tank of a certain fireworks enterprise, containing sulfur, metal powders such as magnesium powder, salts such as barium salts, perlite powder and other components, by mass fraction, the dry basis mainly contains S 32.2%, Al 6.2%, Mg 5.4%, Ba 1.1%, Pb 0.21%, Zn 0.25%, Ni 0.04%, Cu 0.03%, Cr 0.11%, Cd 0.02%, with self-ignition, a small amount of which is placed on an electric furnace for heating, and it will burn violently. Figure 1 As shown, the method of the present invention comprises the following steps: (1) Acid dissolution: Take 20g of hazardous solid waste raw material (wet), with a water content of 88%, add 200mL of water and stir, use 20wt% sulfuric acid to control the pH value to 1.5, stir and react for 1h to obtain a slurry after acid dissolution, which includes an acid solution and slag. This process mainly dissolves metal powder and oxides.

[0019] Mg + H2SO4 = MgSO4 + H2 Zn + H2SO4 = ZnSO4 + H2 2Al + 3H2SO4 = Al2(SO4)3 + 3H2 FeO + H2SO4 = FeSO4 + H2O CaO + H2SO4 = CaSO4 + H2O MgO + H2SO4 = MgSO4 + H2O ZnO + H2SO4 = ZnSO4 + H2O Fe2O3+ 3H2SO4= Fe2(SO4)3+ 3H2O Al2O3+ 3H2SO4= Al2(SO4)3+ 3H2O The components of the acid solution obtained after acid dissolution are shown in the following table.

[0020] Table 1 Element concentration in acid solution (unit: mg / L)

[0021] (2) Alkali dissolution: Add sodium hydroxide to the acid-dissolved slurry (containing acid solution and slag), adjust the mass fraction of sodium hydroxide in the obtained slurry to 3%, control the temperature to 60°C, stir and react for 1 hour to obtain the slurry after alkaline dissolution. This process mainly dissolves sulfur and neutralizes and precipitates metal ions. At the same time, the generated hydroxide colloids such as iron and aluminum can flocculate and precipitate with other heavy metals.

[0022] 3S + 6NaOH = 2Na2S + Na2SO3+ 3H2O 2Fe 3+ + 3S 2- = 2FeS + S Al 3+ + 3OH - = Al(OH)3 Fe 3+ + 3OH - = Fe(OH)3 Fe 2+ + 2OH - = Fe(OH)2 Mg 2+ + 2OH - = Mg(OH)2 Ca 2+ + 2OH - = Ca(OH)2 Zn 2+ + 2OH - = Zn(OH)2 Oxidation: Add 2.5g / L ferrous sulfate (catalyst) to the alkali-dissolved slurry, and use an ozone generator to pass a mixture of ozone and air. The mass concentration of ozone in the mixed gas is 3wt%. Stir and continue to pass the mixed gas for 2h. The amount of ozone used is twice the theoretical amount of redox reaction. This process mainly uses redox reaction to convert S 2- and SO3 2- Oxidized to SO4 2- .

[0023] 3S + 6NaOH = 2Na2S + Na2SO3+ 3H2O Fe 2+ + O3 + H2O = Fe 3+ + O2+ OH - + OH 2Fe 3+ + 3S 2- = 2FeS + S FeS + O3 + H2O = Fe 2+ + S + O2 + 2OH - S 2- + O3+ H2O = S + O2+ 2OH - SO3 2- + O3= SO4 2- + O2 (4) Filtration: The material after oxidation treatment is filtered to obtain filter residue and filtrate. The filter residue is harmless slag, and the filtrate is discharged after adjusting the pH value to 8 and meeting the discharge standards.

[0024] Take the filter residue and heat it on an electric furnace. There should be no redness or burning.

[0025] The composition of the filtrate is shown in the following table.

[0026] Table 2 Filtrate composition (unit: mg / L)

[0027] Comparative Example 1 A method for treating hazardous solid waste in the production of fireworks and firecrackers. The waste residue to be treated is the same as that in Example 1. Take 20g of hazardous solid waste raw material (wet), add 200mL of water and stir, use sulfuric acid to control the pH value to 1.5, and stir to react for 2h.

[0028] After the reaction is completed, filter and take a small amount of filter residue to be calcined in a crucible on an electric discharge furnace. The material will smoke quickly and then burn with crackling and explosion sounds.

[0029] Comparative Example 2 A method for treating hazardous solid waste in the production of fireworks and firecrackers. The waste residue to be treated is the same as that in Example 1. 20 g of hazardous solid waste raw material (wet) is taken, 200 mL of water is added for stirring, and the pH value is controlled to be 1.5 with sulfuric acid. After stirring and reacting for 1 hour, 2.5 g / L of ferrous sulfate is added, and a mixed gas of ozone and air is introduced through an ozone generator, the mass concentration of ozone in the mixed gas is 3 wt%, and the mixed gas is stirred and continuously introduced for reaction for 2 hours.

[0030] After the reaction is completed, filter and take a small amount of filter residue to be calcined in a crucible on an electric discharge furnace. The material will smoke quickly and then burn.

[0031] Comparative Example 3 A method for treating hazardous solid waste in the production of fireworks and firecrackers. The waste residue to be treated is the same as that in Example 1. 20 g of hazardous solid waste raw material (wet) is taken, 200 mL of water is added for stirring, and the pH value is controlled to 1.5 with sulfuric acid. After stirring for 1 hour, 2.5 g / L of ferrous sulfate is added, the material temperature is controlled to 80°C, and the reaction is stirred. A mixed gas of ozone and air is introduced through an ozone generator, the mass concentration of ozone in the mixed gas is 3wt%, and the mixed gas is stirred and continuously introduced for reaction for 2 hours, wherein the amount of ozone used is twice the theoretical amount of redox reaction.

[0032] After the reaction is completed, filter and take a small amount of filter residue to calcine in a crucible on an electric discharge furnace. The material turns black and then burns with smoke.

[0033] Comparative Example 4 A method for treating hazardous solid waste in the production of fireworks and firecrackers, the waste residue to be treated is the same as in Example 1, 20g of hazardous solid waste raw material (wet) is taken, 200mL of water is added for stirring, and the pH value is controlled to 1.5 with sulfuric acid, and stirred for 1 hour. At room temperature, sodium hydroxide is added to adjust the mass fraction of sodium hydroxide in the obtained slurry to 3%, and stirred for 2 hours.

[0034] After the reaction is completed, filter and take a small amount of filter residue to be calcined in a crucible on an electric discharge furnace. The material will smoke quickly with flames of different colors.

[0035] Comparative Example 5 A method for treating hazardous solid waste in the production of fireworks and firecrackers is basically the same as Example 1, with the only difference being that the order of the steps is swapped, i.e., acidification is performed first, followed by oxidation, and then alkalization.

[0036] After the reaction is completed, filter and take a small amount of filter residue and calcine it in a crucible on an electric discharge furnace. The material will turn black and smoke when burning. This is mainly because sulfur is difficult to oxidize directly and will burn during calcination.

[0037] Comparative Example 6 A method for treating hazardous solid waste in the production of fireworks and firecrackers is basically the same as Example 1, except that alkalization is first performed and then acidification is performed. During the acidification process, sulfur decomposes to obtain S 2- and SO3 2- , will react with acids to release highly toxic H2S and SO2 gases.

[0038] Comparative Example 7 A method for treating hazardous solid waste in the production of fireworks and firecrackers is basically the same as Example 1, except that: alkalization is first performed, and then oxidation is performed. During the oxidation process, metal powders such as magnesium powder will react violently with the oxidant, while sulfur and its decomposition S 2- and SO3 2- It is difficult to oxidize completely, and if it is acidified, it will release highly toxic H2S and SO2 gases.

[0039] The above is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as above in the preferred embodiment, it is not used to limit the present invention. Any technician familiar with the art can make many possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent replacement, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention, still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A method for harmlessly treating hazardous solid waste in the production of fireworks and firecrackers, characterized in that: The following steps are involved: (1) Acid dissolution: Add water to the hazardous solid waste generated by fireworks and firecrackers production and stir, then add acid to control the pH value to ≤3, and after stirring and reaction, obtain acid-dissolved slurry; (2) Alkali dissolution: adding alkali to the acid-dissolved slurry, controlling the mass fraction of alkali in the obtained slurry to be 1% to 20%, stirring and reacting at 40°C to 80°C to obtain an alkali-dissolved slurry; (3) Oxidation: adding an oxidant and a catalyst to the alkali-dissolved slurry to carry out a redox reaction under stirring; (4) Filtration: The material obtained by the above oxidation is filtered to obtain filter residue and filtrate. The filter residue is harmless and the filtrate meets the discharge standards.

2. The harmless treatment method for hazardous solid waste in fireworks and firecrackers production according to claim 1 is characterized in that: In step (1), the acid is sulfuric acid or hydrochloric acid, and the stirring reaction time is 0.5h to 2h.

3. The harmless treatment method for hazardous solid waste in fireworks and firecrackers production according to claim 1 is characterized in that: In step (2), the base is one or more of sodium hydroxide, potassium hydroxide and barium hydroxide, and the stirring reaction time is 0.5h to 4h.

4. The harmless treatment method for hazardous solid waste in fireworks and firecrackers production according to claim 1 is characterized in that: In step (3), the oxidant is one or more of hydrogen peroxide, ozone, hypochlorite, chlorate, permanganate and persulfate, and the amount of the oxidant is 1 to 4 times the theoretical amount of the redox reaction; the catalyst is one or more of iron salt, ferrous salt and cupric salt, and the amount of the catalyst in the slurry after alkali dissolution is 0.1 g / L to 10 g / L.

5. The method for harmlessly treating hazardous solid wastes in the production of fireworks and firecrackers according to any one of claims 1 to 4, characterized in that: In step (3), the redox reaction time is 0.5h to 4h.

6. The method for harmlessly treating hazardous solid wastes in the production of fireworks and firecrackers according to any one of claims 1 to 4, characterized in that: In step (4), the filtrate is discharged after adjusting the pH value to 6 to 9 and meeting the discharge standards.

Images