Device and method for combined treatment of waste hydrazine hydrate and waste raney nickel

Abstract

The present application relates to the technical field of hazardous waste treatment, and particularly relates to a device and method for treating waste Raney nickel by combining hydrazine hydrate and wastewater. The method for treating waste Raney nickel by combining hydrazine hydrate and wastewater comprises the following steps: reacting waste Raney nickel with dilute sulfuric acid to obtain a mixed solution one and hydrogen. Then, hydrogen peroxide and sodium hydroxide solution are sequentially added to the mixed solution one to adjust the pH value to 3-7, and a suspension one is obtained and filtered. Sodium hydroxide solution is added to the filtered filtrate one until the pH value is 8-9, and then the filtrate one is heated to 85 DEG C. Then, hydrazine hydrate is added, and after stirring for 3 h, a suspension two is obtained, and then the suspension two is filtered to obtain filtrate two and filter residue, and the filter residue is elemental nickel. Through the above treatment method, waste Raney nickel and hydrazine hydrate can be treated in combination, the two kinds of hazardous wastes with high activity can be safely and harmlessly treated, and after treatment, elemental nickel with a purity of more than 95% and hydrogen can be obtained, and comprehensive utilization of nickel and hydrogen resources is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of hazardous waste treatment, in particular to a device and method for treating waste Raney nickel by using waste hydrazine hydrate. BACKGROUND

[0002] Raney nickel is a solid heterogeneous catalyst composed of fine grains of nickel-aluminum alloy with a porous structure. It is a widely used industrial catalyst. Raney nickel can be used in catalytic hydrogenation processes of unsaturated alkenes, alkynes, nitro groups, cyano groups, or carbonyl groups, and can also be used in hydrogenation reactions of polymers with unsaturated bonds, as well as hydrogenolysis, isomerization, and cyclization of saturated hydrocarbons. As a hydrogenation catalyst in petroleum chemical production, Raney nickel will lose activity after a certain period of use and needs to be replaced regularly. The chemical composition of waste Raney nickel catalyst is complex, with nickel being the main component, followed by aluminum, and also containing a small amount of iron, chromium, or silicon dioxide, as well as organic impurities. Due to the high content of nickel in waste Raney nickel catalyst, it can be comprehensively recycled as a nickel resource, and waste Raney nickel contains a certain amount of hydrogen gas, which is highly active and flammable, making the treatment more difficult.

[0003] Hydrazine hydrate, also known as hydrazine hydrate, is an important chemical intermediate with a wide range of uses. One of its main uses is in the production of blowing agents. The main production processes of hydrazine hydrate include the urea method and the ketone hydrazine method. The energy consumption and waste of the ketone hydrazine method are much lower than those of the urea method, and it has become the mainstream process for producing hydrazine hydrate. Hydrazine hydrate decomposes into N2, NH3, and H2 at high temperatures. Hydrazine hydrate has very strong reducing properties and reacts violently with halogens, HNO3, KMnO4, etc. It can absorb CO2 in the air and produce smoke. In the production process of hydrazine hydrate and the chemical production process using hydrazine hydrate as raw material or solvent, hydrazine hydrate can easily enter the wastewater system due to incomplete reaction, leakage, cleaning, etc. These hydrazine hydrate wastewater has strong toxicity and activity, making it difficult to handle, and also poses potential hazards to the human body and the environment.

[0004] In the prior art, whether it is waste Raney nickel or waste hydrazine hydrate, both are hazardous waste and have strong activity, resulting in high safety risk in the entire treatment process. SUMMARY

[0005] In order to solve the problem that waste Raney nickel and waste hydrazine hydrate in the prior art are both hazardous waste and have strong activity, resulting in high safety risk in the entire treatment process, the present application provides a device and method for treating waste Raney nickel by using waste hydrazine hydrate.

[0006] To achieve the above object, the technical scheme adopted by the present application is as follows: a method for treating waste Raney nickel by using waste hydrazine hydrate, comprising the following steps:

[0007] (1) reacting the waste Raney nickel with dilute sulfuric acid to obtain a mixed solution I and hydrogen, and collecting and storing the hydrogen by using a collecting device, and the reaction equation is as follows:

[0008] Ni+2H2SO4=NiSO4+2H2↑

[0009] 2Al+3H2SO4=Al2(SO4)3+3H2↑

[0010] Fe+H2SO4=FeSO4+H2↑

[0011] The mixed solution I comprises a nickel sulfate solution, an aluminum sulfate solution and a ferrous sulfate solution;

[0012] (2) first adding hydrogen peroxide to the mixed solution I to oxidize all the ferrous ions in the mixed solution I into trivalent iron ions; then adding a sodium hydroxide solution to adjust the pH value to 3-7 to obtain a suspension I; then filtering the suspension I to obtain a filtrate I, and the reaction equation is as follows:

[0013] 2Fe 2+ +H2O2+2H + =2Fe 3+ +2H2O

[0014] Fe2(SO4)3+6NaOH=2Fe(OH)3↓+3Na2SO4

[0015] Al2(SO4)3+6NaOH=2Al(OH)3↓+3Na2SO4

[0016] (3) continuously adding the sodium hydroxide solution to the filtrate I until the pH value is 8-9, heating the filtrate I after adjusting the pH value to 85℃, adding waste hydrazine hydrate to the heated filtrate I, stirring for 3h to obtain a suspension II, filtering the suspension II to obtain a filtrate II and a filter residue, washing and drying the filter residue to obtain the filter residue as elemental nickel; and the reaction equation is as follows:

[0017] 2NiSO4+N2H4+4NaOH=2Ni↓+N2↑+4H2O+2Na2SO4

[0018] The filtrate I in the step (3) does not contain iron ions and aluminum ions.

[0019] As a further improvement of the above scheme, the mass fraction of the hydrogen peroxide is 25%-30%.

[0020] As a further improvement of the above-mentioned solution, the mass fraction of the sodium hydroxide solution added in the step (2) and the step (3) is 32%.

[0021] As a further improvement of the above-mentioned solution, the mass fraction of the dilute sulfuric acid is 10%-30%.

[0022] As a further improvement of the above-mentioned solution, the filtrate two is pumped into a sewage treatment system by a filtrate pump for biochemical treatment, so that the filtrate two can be directly discharged after reaching the discharge standard.

[0023] As a further improvement of the above-mentioned solution, the ratio of the amount of the dilute sulfuric acid to the amount of the waste Raney nickel is 2:1.

[0024] As a further improvement of the above-mentioned solution, the volume ratio of the filtrate one to the hydrazine hydrate is 20:1.

[0025] As a further improvement of the above-mentioned solution, the volume of the hydrogen peroxide added in the step (2) is 3%-5% of the volume of the mixed solution one.

[0026] As a further improvement of the above-mentioned solution, the content of iron ions and aluminum ions in the filtrate one needs to be detected before the step (3) is performed, and when the filtrate one still contains iron ions and aluminum ions, the step (2) needs to be repeated until the filtrate one of the step (2) does not contain iron ions and aluminum ions.

[0027] As a further improvement of the above-mentioned solution, the waste Raney nickel and the dilute sulfuric acid in the step (1) are added in a closed reaction container, and water needs to be added into the closed reaction container before the dilute sulfuric acid is added.

[0028] A device for treating waste hydrazine hydrate combined with waste Raney nickel, which adopts the method for treating waste hydrazine hydrate combined with waste Raney nickel as described above.

[0029] A device for treating waste hydrazine hydrate combined with waste Raney nickel, which comprises a reaction device one, a filtering device one, a reaction device two and a filtering device two, the reaction device one is used for treating the waste Raney nickel to obtain the suspension one; the waste Raney nickel to be treated is loaded into the reaction device one and the waste Raney nickel is treated by adding dilute sulfuric acid into the reaction device one; one end of the filtering device one is connected with the reaction device one, the other end of the filtering device one is connected with the reaction device two, the filtering device one is used for filtering the suspension one and conveying the filtrate one into the reaction device two; the reaction device two is used for treating the filtrate one and the hydrazine hydrate in combination to obtain the suspension two; the filtering device two is used for filtering the suspension two to obtain the filtrate two and the residue.

[0030] As a further improvement of the above-mentioned scheme, the reaction device one is a sealed tank structure.

[0031] As a further improvement of the above-mentioned scheme, the reaction device one is further connected with a feeding device, a liquid storage tank one, a liquid storage tank two and a gas collecting device, the feeding device is communicated with the reaction device one, and the feeding device is used for feeding the waste Raney nickel into the reaction device one; the liquid storage tank one is connected with the reaction device one, and the liquid storage tank one is used for storing the dilute sulfuric acid; the liquid storage tank two is provided with two outlets, and the two outlets are connected with the reaction device one and the reaction device two respectively, and the liquid storage tank two is used for storing a sodium hydroxide solution; and the gas collecting device is connected with a gas outlet of the reaction device one, and the gas collecting device is used for collecting hydrogen generated in the reaction device one.

[0032] Further, the reaction device two is further connected with a liquid storage tank three, and the liquid storage tank three is used for adding the waste hydrazine hydrate into the reaction device two.

[0033] Compared with the prior art, the present application has the beneficial effects that:

[0034] (1) The present application can realize the safe and harmless treatment of the waste Raney nickel and the waste hydrazine hydrate, and the comprehensive utilization of the nickel and hydrogen resources, by jointly treating the two kinds of solid hazardous waste and liquid hazardous waste with high activity, i.e. the waste Raney nickel and the waste hydrazine hydrate, and reducing the deactivated nickel ions to obtain the pure nickel by using the strong reducing property of the hydrazine hydrate, and oxidizing the hydrazine hydrate to obtain the non-toxic nitrogen gas. At the same time, the joint treatment can also recover the nickel in the waste Raney nickel to obtain the pure nickel with a purity of more than 95%. In addition, the clean and pollution-free energy hydrogen can also be obtained in the joint treatment process.

[0035] (2) In the present application, the waste Raney nickel is first reacted with dilute sulfuric acid to convert the waste Raney nickel with high activity into stable nickel ions, and the ferrous ions are first converted into ferric ions by adding hydrogen peroxide, and then the impurity iron and impurity aluminum in the waste Raney nickel are removed by adding a sodium hydroxide solution, so that the filtrate after filtration can be jointly treated with the waste hydrazine hydrate to obtain the pure nickel with a purity of more than 95%, and the nickel resources can be recycled and comprehensively utilized.

[0036] (3) Through a series of experimental data in Example 2 to Example 6, it can be proved that the method for treating waste Raney nickel combined with waste hydrazine hydrate can effectively and safely treat two kinds of hazardous waste with strong activity, and after treatment, elemental nickel and hydrogen can be obtained, and through the detection of the treated waste liquid by the instrument, the content of nickel ions in the waste liquid is less than 1 mg / L, which meets the water quality standard for sewage discharge into the urban sewer, thereby verifying from the side that the process of treating waste Raney nickel and waste hydrazine hydrate in the application is green and environmentally friendly, and meets the requirements of green chemistry. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 The device structure schematic diagram for treating waste Raney nickel combined with waste hydrazine hydrate in Example 5 and Example 6 provided by the application is shown.

[0038] In the figure: 1, reaction device one; 11, feeding device; 12, liquid storage tank one; 13, liquid storage tank two; 14, gas collection device; 141, induced draft fan; 142, pressurized collection device; 2, filtration device one; 3, reaction device two; 31, liquid storage tank three; 4, filtration device two. DETAILED DESCRIPTION

[0039] In the following, the application will be further described in conjunction with specific embodiments, and it should be noted that the following described embodiments or technical features can be combined in any manner to form new embodiments without conflict.

[0040] In the description of the application, it should be noted that for orientation words, such as terms "center", "transverse", "longitudinal", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate the orientation and positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the application and simplifying the description, and are not intended to indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and cannot be understood as limiting the specific protection scope of the application. The terms "first", "second", etc. in the specification and claims of the application are used to distinguish similar objects, and do not necessarily describe a specific order or sequence. The terms "include" and "have" in the specification and claims of the application and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not necessarily limit to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0041] Example 1

[0042] The embodiment provides a method for treating waste Raney nickel by combining waste hydrazine hydrate, which comprises the following steps.

[0043] (1) reacting the waste Raney nickel with dilute sulfuric acid to obtain a mixed solution I and hydrogen, and collecting and storing the hydrogen by using a collecting device. The reaction equation is as follows:

[0044] Ni+2H2SO4=NiSO4+2H2↑

[0045] 2Al+3H2SO4=Al2(SO4)3+3H2↑

[0046] Fe+H2SO4=FeSO4+H2↑

[0047] The mixed solution I comprises a nickel sulfate solution, an aluminum sulfate solution and a ferrous sulfate solution.

[0048] (2) adding hydrogen peroxide to the mixed solution I to oxidize all the ferrous ions in the mixed solution I into ferric ions; then adding a sodium hydroxide solution to the mixed solution I to adjust the pH value to 3-7, to obtain a suspension I; and then filtering the suspension I to obtain a filtrate I. The reaction equation is as follows:

[0049] 2Fe 2+ +H2O2+2H + =2Fe 3+ +2H2O

[0050] Fe2(SO4)3+6NaOH=2Fe(OH)3↓+3Na2SO4

[0051] Al2(SO4)3+6NaOH=2Al(OH)3↓+3Na2SO4

[0052] (3) continuously adding the sodium hydroxide solution to the filtrate I until the pH value is 8-9, heating the filtrate I after the pH value is adjusted to 85 DEG C, adding waste hydrazine hydrate to the heated filtrate I, stirring for 3h to obtain a suspension II, filtering the suspension II to obtain a filtrate II and a filter residue, and washing and drying the filter residue, and the filter residue is elemental nickel. The reaction equation is as follows:

[0053] 2NiSO4+N2H4+4NaOH=2Ni↓+N2↑+4H2O+2Na2SO4

[0054] The embodiment realizes the recovery of waste Raney nickel by the above operation, and the recovered nickel element has a purity of 95% or above. In addition, during the pretreatment of waste Raney nickel, i.e. the reaction of waste Raney nickel with dilute sulfuric acid, the activity of nickel in waste Raney nickel is reduced, and clean and pollution-free energy hydrogen is obtained. Therefore, the present application realizes the comprehensive utilization of nickel and hydrogen resources by the combined treatment of waste Raney nickel and waste hydrazine hydrate.

[0055] It can be understood that, in actual operation, the content of iron ions and aluminum ions in the filtrate I in step (2) needs to be detected before step (3) is performed. The concentration of iron ions and aluminum ions in the filtrate I can be detected by an ICP spectrometer. When the ICP spectrometer detects that there are no iron ions and aluminum ions in the filtrate I, the operation of step (3) can be performed. When the ICP spectrometer detects that there are still iron ions and aluminum ions in the filtrate I, the operation of step (2) needs to be repeated until all the iron ions in the filtrate I are converted into iron hydroxide precipitate and all the aluminum ions are converted into aluminum hydroxide precipitate, and then the suspension I in step (2) is filtered before the operation of step (3) is performed. The above purpose is to ensure that the iron ions and aluminum ions in step (2) are completely removed.

[0056] Preferably, the volume ratio of the filtrate I to the waste hydrazine hydrate can be 20:1. In actual experiments, different volume ratios of the filtrate I to the waste hydrazine hydrate are added for experiments, such as a volume ratio of 10:1, a volume ratio of 15:1, a volume ratio of 20:1, a volume ratio of 30:1, etc. It is found that when the volume ratio of the filtrate I to the waste hydrazine hydrate is 20:1, the purity of the obtained nickel element is the best, and the content of nickel in the filtrate II is the lowest.

[0057] In step (2) and step (3), the mass fraction of the added sodium hydroxide solution is 32%.

[0058] The ratio of the amount of dilute sulfuric acid to waste Raney nickel can be 2:1. By adding different proportions of dilute sulfuric acid and waste Raney nickel in the pre-experiment, it can be known that when the ratio of the amount of dilute sulfuric acid to waste Raney nickel is 2:1, the treatment effect is best. When the amount of dilute sulfuric acid is small, the dilute sulfuric acid at this time cannot completely dissolve the waste Raney nickel into nickel sulfate, resulting in that the inactivation treatment of the waste Raney nickel is not thorough enough. When the amount of dilute sulfuric acid is too much, it will cause waste of materials, and more alkali is needed to adjust the pH value in the later stage, resulting in an increase in the cost of the whole treatment process.

[0059] The dilute sulfuric acid can be selected from dilute sulfuric acid with a mass fraction of 10%-30%.

[0060] The hydrogen peroxide can be selected from hydrogen peroxide with a mass fraction of 25%-30%.

[0061] Step (1) needs to be carried out in an air-tight container, and before the reaction, an appropriate amount of ultrapure water is added to the reaction container. The purpose of adding ultrapure water is to cover the waste Raney nickel to prevent it from contacting with air. On the other hand, the ultrapure water can play a buffering role in the reaction between the waste Raney nickel and the dilute sulfuric acid, ensuring that the waste Raney nickel and the dilute sulfuric acid can react smoothly, and the hydrogen gas generated in the reaction can also be released stably.

[0062] In step (1), the waste Raney nickel and the dilute sulfuric acid need to be stirred when they react. When there is no more gas bubble generated in the reaction system, it can be considered that the reaction between the waste Raney nickel and the dilute sulfuric acid is complete.

[0063] Before treating the waste Raney nickel and the waste hydrazine hydrate, the waste Raney nickel is treated with dilute sulfuric acid. The purpose of this operation is that the waste Raney nickel has strong activity. After being dissolved by dilute sulfuric acid, a nickel sulfate solution is formed. The nickel ions in the nickel sulfate solution are much more stable than the elemental nickel in the waste Raney nickel, thereby improving the safety in the treatment process.

[0064] In step (2), hydrogen peroxide is first added to the mixed solution I to oxidize all the ferrous ions in the mixed solution I into ferric ions, and then sodium hydroxide solution is added to adjust the pH value to 3-7. The reason for this operation is that the mixed solution I contains ferrous ions and aluminum ions, and the solubility product ksp of ferrous hydroxide is relatively close to the solubility product ksp of nickel hydroxide. If sodium hydroxide is directly added for precipitation and impurity removal, the ferrous ions cannot be completely removed, so it is necessary to first use hydrogen peroxide to oxidize the ferrous ions into ferric ions. The solubility products ksp of aluminum hydroxide and iron hydroxide are both much smaller than the solubility product ksp of nickel hydroxide (the ksp of aluminum hydroxide is 1.3*10 -33 , the ksp of iron hydroxide is 3.2*10 -38 , and the ksp of nickel hydroxide is 2.0*10 -15), so when the precipitation reaction occurs, iron ions and aluminum ions will be precipitated preferentially. Therefore, in step (2), by adjusting the pH of the solution to be between 3 and 7, both iron ions and aluminum ions will form precipitates, and then the precipitates are removed by filtration, thereby achieving the purpose of removing the ferrous ions and aluminum ions in the mixed solution I.

[0065] It can be understood that the filter residue obtained in step (3) is elemental nickel, and the filtrate II obtained can be pumped into a sewage treatment system for biochemical treatment, so that the filtrate II after biochemical treatment can be directly discharged after meeting the discharge standard.

[0066] In step (3), the purity of elemental nickel in the filter residue can be detected by a handheld XRF detector. The content of nickel ions in the filtrate I of step (2) and the content of nickel ions in step (3) can be detected by an ICP spectrometer.

[0067] In step (3), the filtrate I can be heated by a constant temperature water bath.

[0068] Example 2

[0069] (1) Take 10.1g of Raney nickel and place it in a three-necked flask (one neck is a thermometer with a rubber stopper, one neck is a dosing port with a rubber stopper, and the other neck is connected to a hydrogen gas collection device), then add 200mL of ultrapure water to the three-necked flask, and then add 20.2mL of 10% mass fraction dilute sulfuric acid, and stir for 12h until no bubbles are generated in the system.

[0070] (2) First, add 10.1ml of 27.5% mass fraction hydrogen peroxide to the three-necked flask, and stir until the reaction is complete, then add 8.5mL of 32% mass fraction sodium hydroxide solution, adjust the pH of the solution in the three-necked flask to 3-7, and stir for 1h before filtering to obtain a filtrate I with a volume of 226mL. The content of nickel ions in the filtrate I is 34440mg / L, which is detected by an ICP spectrometer. At the same time, it is necessary to detect whether the filtrate I contains iron ions and aluminum ions by an ICP spectrometer. If the filtrate I contains iron ions and aluminum ions, step (2) needs to be repeated. If the filtrate I is detected by the ICP spectrometer to not contain iron ions and aluminum ions, step (3) can be directly performed.

[0071] (3) continue to add 3.7 mL of a 32% by mass sodium hydroxide solution to the filtrate one, and then adjust the pH to 8-9. Place it in a constant temperature water bath for heating, and then heat it to 85°C. Then add 11.3 mL of hydrazine hydrate to it, and then stir for 3 h, and then filter to obtain filtrate two and a filter residue. The content of nickel ions in the filtrate two is 0.98 mg / L by ICP spectrometer detection. The filter residue after filtration is placed in an oven and dried at 105°C for 12 h, and then weighed to obtain a filter residue weight of 7.78 g. The content of nickel in the filter residue is detected by a handheld XRF detector, and the content of nickel in the filter residue is about 99.9%.

[0072] From the above examples, it can be seen that the operations of steps (1) and (2) can effectively achieve the inactivation treatment of waste Raney nickel, i.e. all the nickel elements in the Raney nickel are converted into nickel ions. The content of nickel ions is 34440 mg / L, which is verified by detecting the content of nickel ions in the filtrate one in step (2), so that all the nickel elements in the waste Raney nickel are converted into stable nickel ions, thereby greatly reducing the activity of the waste Raney nickel, to ensure the safety of the subsequent combined treatment of the waste Raney nickel and hydrazine hydrate. In addition, under the action of step (1), the waste Raney nickel is also completely dissolved, so that the impurity iron becomes ferrous ions and the impurity aluminum becomes aluminum ions, and then step (2) is performed, i.e. by sequentially adding hydrogen peroxide and sodium hydroxide solution and adjusting the pH value to 3-7, the ferrous ions and aluminum ions dissolved in step (1) are precipitated, thereby removing the impurity iron and aluminum in the waste Raney nickel. The filtrate one in step (3) does not contain iron ions and aluminum ions, thereby improving the purity of the nickel element in the filter residue extracted, and the weight of the filter residue in step (3) of the present example is about 7.78 g, and the content of nickel in the filter residue is about 99.9%. From this experimental data, it can be seen that under the strong reducing property of hydrazine hydrate, most of the nickel elements in the waste Raney nickel are purified, and the purity of the extracted nickel element is very high. Therefore, by the above operation, the nickel element in the Raney nickel is recycled and utilized, and the hydrazine hydrate is also oxidized to non-toxic nitrogen gas. Therefore, it is proved that by the combined treatment of the two hazardous wastes in the present example, not only the nickel element with a purity of about 99.9% can be obtained, but also the hydrazine hydrate is converted into non-toxic nitrogen gas for emission. In addition, the content of nickel ions in the filtrate two in step (3) is 0.98 mg / L, which is less than 1 mg / L, and meets the water quality standard for wastewater discharge into urban sewers, thereby verifying from the side that the process of the combined treatment of the waste Raney nickel and hydrazine hydrate in the present example is green and environmentally friendly, and meets the requirements of green chemistry.

[0073] Example 3

[0074] (1) Take 10 g of waste Raney nickel and place it in a three-necked flask (one neck is equipped with a thermometer with a rubber stopper, one neck is equipped with a rubber stopper for adding chemicals, and the other neck is connected to a hydrogen gas collection device), then add 200 mL of ultrapure water to the three-necked flask, then add 15.1 mL of 10% mass fraction dilute sulfuric acid, and stir for 12 h until no bubbles are generated in the system.

[0075] (2) First, add 10.5 ml of 27.5% mass fraction hydrogen peroxide to the three-necked flask, stir until the reaction is complete, then add 7.6 mL of 32% mass fraction sodium hydroxide solution, adjust the pH of the solution in the three-necked flask to 3-7, stir for 1 h, then filter to obtain a filtrate one with a volume of 213 mL, then detect the content of nickel ions in the filtrate one by ICP spectrometer to be 32600 mg / L; At the same time, it is necessary to detect whether the filtrate one contains iron ions and aluminum ions by ICP spectrometer, if the filtrate one contains iron ions and aluminum ions, then the step (2) needs to be repeated; If the filtrate one does not contain iron ions and aluminum ions by ICP spectrometer, then step (3) can be directly performed.

[0076] (3) Continue to add 2.3 mL of 32% mass fraction sodium hydroxide solution to the filtrate one, and adjust its pH to 8-9, then place it in a constant temperature water bath for heating, heat to 85℃, then add 10.7 mL of waste hydrazine hydrate, then stir for 3 h, then filter to obtain a filtrate two and a filter residue. The content of nickel ions in the filtrate two is 0.75 mg / L by ICP spectrometer. The filter residue after filtration is placed in an oven at 105℃ for 12 h, then weighed to obtain the weight of the filter residue as 6.94 g. The content of nickel in the filter residue is about 98.4% by handheld XRF detector.

[0077] It can be seen from the above examples that the operations of steps (1) and (2) can effectively achieve the inactivation treatment of waste Raney nickel, that is, the elemental nickel in the Raney nickel is completely converted into nickel ions. Specifically, the content of nickel ions is verified to be 32600 mg / L by detecting the content of nickel ions in the filtrate I in step (2), so that the elemental nickel in the waste Raney nickel is completely converted into stable nickel ions, thereby greatly reducing the activity of the waste Raney nickel to ensure the safety of the subsequent combined treatment of the waste Raney nickel and the hydrazine hydrate. In addition, under the action of step (1), the waste Raney nickel is completely dissolved, so that the impurity iron becomes ferrous ions and the impurity aluminum becomes aluminum ions, and then step (2) is performed to realize the precipitation of the ferrous ions and aluminum ions dissolved in step (1) by sequentially adding hydrogen peroxide and sodium hydroxide solution and adjusting the pH value to 3-7, thereby removing the impurity iron and aluminum in the waste Raney nickel. The filtrate I in step (3) does not contain iron ions and aluminum ions, thereby improving the purity of the elemental nickel in the filter residue extracted. The weight of the filter residue in step (3) of the present example is about 6.94 g, and the content of nickel in the filter residue is about 98.4%. From this experimental data, it can be seen that under the strong reducing property of the hydrazine hydrate, most of the elemental nickel in the waste Raney nickel is purified, and the purity of the extracted elemental nickel is very high. Therefore, by the above operation, the elemental nickel in the Raney nickel is recycled and utilized, and the hydrazine hydrate is also oxidized to non-toxic nitrogen gas. Therefore, it is proved that by the combined treatment of the two hazardous wastes in the present example, not only the elemental nickel with a purity of about 98.4% can be obtained, but also the hydrazine hydrate is converted into non-toxic nitrogen gas for discharge. In addition, the content of nickel ions in the filtrate II in step (3) is 0.75 mg / L, which is less than 1 mg / L, meeting the water quality standard for sewage discharge into urban sewers, thereby verifying from the side that the process of the combined treatment of the waste Raney nickel and the hydrazine hydrate in the present example is green and environmentally friendly, meeting the requirements of green chemistry.

[0078] Example 4

[0079] 10 g of waste Raney nickel was weighed and placed in a three-necked flask (one neck was equipped with a thermometer with a rubber stopper, one neck was equipped with a rubber stopper for adding chemicals, and the other neck was connected to a hydrogen gas collection device), 200 mL of ultrapure water was then added to the three-necked flask, followed by the addition of 20.3 mL of 10% mass fraction dilute sulfuric acid, and the reaction was stirred for 12 h until no bubbles were generated in the system.

[0080] (2) first add 10.3 ml of 27.5% mass fraction hydrogen peroxide to a three-necked flask, after stirring until the reaction is complete, add 8.1 mL of 32% mass fraction sodium hydroxide solution, adjust the pH of the solution in the three-necked flask to 3-7, stir for 1 h, then filter to obtain filtrate one with a volume of 209 mL, then detect the content of nickel ions in the filtrate one by ICP spectrometer to be 38440 mg / L; at the same time, detect whether the filtrate one contains iron ions and aluminum ions by ICP spectrometer, if the filtrate one contains iron ions and aluminum ions, repeat step (2); if the filtrate one does not contain iron ions and aluminum ions detected by ICP spectrometer, directly proceed to step (3).

[0081] (3) continue to add 3.1 mL of 32% mass fraction sodium hydroxide solution to the filtrate one, after adjusting its pH to 8-9, place it in a constant temperature water bath for heating, heat to 85℃, then add 10.5 mL of hydrazine hydrate to it, then stir for 3 h, then filter to obtain filtrate two and filter residue. Detect the content of nickel ions in the filtrate two by ICP spectrometer to be 0.99 mg / L. Place the filtered filter residue in an oven and dry at 105℃ for 12 h, then take it out and weigh to obtain the weight of the filter residue to be 8.03 g. Detect the content of nickel in the filter residue by handheld XRF detector to be about 99.1%.

[0082] It can be seen from the above examples that the operations of steps (1) and (2) can effectively achieve the inactivation treatment of waste Raney nickel, that is, the elemental nickel in the Raney nickel is completely converted into nickel ions. Specifically, the content of nickel ions is verified to be 38440 mg / L by detecting the content of nickel ions in the filtrate I in step (2), so that the elemental nickel in the waste Raney nickel is completely converted into stable nickel ions, thereby greatly reducing the activity of the waste Raney nickel to ensure the safety of the subsequent combined treatment of the waste Raney nickel and the waste hydrazine hydrate. In addition, under the action of step (1), the waste Raney nickel is also completely dissolved, so that the impurity iron therein becomes ferrous ions and the impurity aluminum becomes aluminum ions. Then, by adding hydrogen peroxide and sodium hydroxide solution in sequence and adjusting the pH value to 3-7 in step (2), the ferrous ions and aluminum ions dissolved in step (1) are precipitated, thereby removing the impurity iron and aluminum in the waste Raney nickel. The filtrate I in step (3) does not contain iron ions and aluminum ions, thereby improving the purity of the elemental nickel in the filter residue extracted. The weight of the filter residue in step (3) of the present example is about 8.03 g, and the content of nickel in the filter residue is about 99.1%. It can be seen from this experimental data that most of the elemental nickel in the waste Raney nickel is purified under the strong reducing property of the waste hydrazine hydrate, and the purity of the extracted elemental nickel is very high. Therefore, by the above operation, the elemental nickel in the Raney nickel is recycled and utilized, and the waste hydrazine hydrate is also oxidized to non-toxic nitrogen gas. Therefore, it is proved that by the combined treatment of the two hazardous wastes in the present example, not only the elemental nickel with a purity of about 99.1% can be obtained, but also the waste hydrazine hydrate is converted into non-toxic nitrogen gas for discharge. In addition, the content of nickel ions in the filtrate II in step (3) is 0.99 mg / L, which is less than 1 mg / L, meeting the water quality standard for sewage discharge into urban sewers, thereby verifying from the side that the process of combined treatment of the waste Raney nickel and the waste hydrazine hydrate in the present example is green and environmentally friendly, meeting the requirements of green chemistry.

[0083] Examples 2 to 4 in the present application are experimental operation steps for combined treatment of waste Raney nickel and waste hydrazine hydrate under laboratory conditions. It can be proved by Examples 2 to 4 that the treatment method of the present application can effectively treat waste Raney nickel and waste hydrazine hydrate. It utilizes the strong reducing property of hydrazine hydrate to reduce the deactivated nickel ions to obtain elemental nickel, and itself is oxidized to non-toxic nitrogen gas. At the same time, the nickel in the waste Raney nickel is recycled, and elemental nickel with a purity of more than 95% can be obtained. Clean and pollution-free energy hydrogen gas can also be obtained in the process, realizing comprehensive utilization of nickel and hydrogen resource recycling.

[0084] Example 5

[0085] The present example lists the operation steps for combined treatment of waste Raney nickel and waste hydrazine hydrate in an actual factory.

[0086] (1) Take 10 kg of waste Raney nickel and place it in a sealed reaction vessel. Add 2 m 3 of tap water, then add 10% dilute sulfuric acid 19.8 L, stir for 12 h until no bubbles are generated in the system.

[0087] (2) First add 10.3 L of 27.5% hydrogen peroxide to the reaction vessel of step (1), stir until the reaction is complete, then add 9.7 L of 32% liquid alkali, adjust the pH to 3-7, stir for 1 h, then filter to obtain a filtrate with a volume of 2.13 m 3 . The content of nickel ions in the filtrate is 3280 mg / L, which is detected by ICP spectrometer. At the same time, ICP spectrometer can also detect whether the filtrate contains iron ions and aluminum ions. If the filtrate contains iron ions and aluminum ions, step (2) needs to be repeated; if the filtrate does not contain iron ions and aluminum ions, step (3) can be directly performed.

[0088] (3) Continue to add 2.8 L of 32% liquid alkali to the filtrate, adjust the pH of the system to 8-9, heat through the steam pipeline, heat to 85℃, then add 10.7 L of waste hydrazine hydrate, stir for 3 h, filter, and obtain filtrate two and filter residue. The content of nickel ions in the filtrate is about 0.97 mg / L, which is detected by ICP spectrometer.

[0089] (4) Place the filter residue in an oven at 105℃ for 12 h, then take it out and weigh it to obtain 6.97 kg of filter residue. The content of nickel in the filter residue is greater than 99.9%, which is detected by a handheld XRF detector.

[0090] Example 6

[0091] (1) Take 50 kg of waste Raney nickel and place it in a sealed reaction vessel. Add 5 m 3 of tap water, then add 10% dilute sulfuric acid 100.3 L, stir for 12 h until no bubbles are generated in the system.

[0092] (2) First add 49.8 L of 27.5% hydrogen peroxide to the reaction vessel of step (1), stir until the reaction is complete, then add 99.6 L of 32% liquid alkali, adjust the pH to 3-7, stir for 1 h, then filter to obtain a filtrate with a volume of 5.17 m 3The content of nickel ions in the filtrate one is 5780 mg / L by ICP spectrometer. At the same time, whether the filtrate one contains iron ions and aluminum ions can also be detected by ICP spectrometer. If the filtrate one contains iron ions and aluminum ions, step (2) needs to be repeated. If the filtrate one does not contain iron ions and aluminum ions by ICP spectrometer, step (3) can be directly performed.

[0093] (3) Continue to add 32% liquid caustic 10.6 L to the filtrate one, adjust the pH of the system to 8-9, heat by steam pipeline to 85℃, then add hydrazine hydrate 51.1 L, stir for 3 h, filter, and obtain filtrate two and filter residue. The content of nickel ions in the filtrate one is about 0.67 mg / L by ICP spectrometer.

[0094] (4) Place the filter residue in an oven at 105℃ for 12 h, take it out and weigh, and obtain filter residue 29.8 kg. The content of nickel in the filter residue is greater than 99.9% by handheld XRF detector.

[0095] From example 5 and example 6, it can be known that the method for treating waste Raney nickel by hydrazine hydrate in the application can be applied to actual production application. From the data of example 5 and example 6, it can be known that the treatment method provided in the application can effectively treat waste hydrazine hydrate and waste Raney nickel, and the product after treatment is nickel single element and hydrogen, and the waste liquid after treatment will not cause harm to the environment, which meets the water quality standard for sewage discharge into the urban sewer. Therefore, this combined treatment can effectively treat two kinds of hazardous waste at the same time, and the whole treatment stage and after treatment will not cause harm to the environment, which meets the requirements of green chemistry. In addition, the product of nickel single element after the combined treatment of waste hydrazine hydrate and waste Raney nickel has very high purity, which can be recycled and utilized, thereby reducing the waste of chemical resources.

[0096] From example 5 and example 6, it can be known that, in the treatment process, the amount of tap water added in step (1) is 10 times larger than the ratio of example 2 to example 4. The purpose of this operation is that the reaction container is relatively large in the actual treatment process, and the water amount is a little small according to the laboratory ratio, which cannot completely immerse the waste Raney nickel, so that the Raney nickel will be in contact with the air. In addition, because the amount of waste Raney nickel is large in the actual treatment process in the factory, more water is added to dilute the whole solution in order to further ensure the safety of the experiment, so that the whole treatment process can be carried out stably and gently, and the safety in the treatment process is improved.

[0097] Example 7

[0098] A device for treating waste hydrazine hydrate combined with waste Raney nickel, which can be applied to the method for treating waste hydrazine hydrate combined with waste Raney nickel in Embodiment 5 or Embodiment 6.

[0099] Please refer to Figure 1 A device for treating waste hydrazine hydrate combined with waste Raney nickel, which includes reaction device one 1, filtering device one 2, reaction device two 3, and filtering device two 4.

[0100] The reaction device one 1 is a sealed tank structure. The reaction device one 1 is used for treating waste Raney nickel to obtain a suspension one. First, the waste Raney nickel to be treated is placed in the reaction device one 1, and then a certain amount of tap water is added so that the tap water can completely cover the waste Raney nickel. Then, the waste Raney nickel is treated by adding dilute sulfuric acid to the reaction device one 1, so that the waste Raney nickel with high activity becomes stable nickel ions. During the addition of tap water, the amount of tap water needs to be large enough to completely cover the waste Raney nickel placed in the reaction device one 1, and after the addition of dilute sulfuric acid, the concentration of nickel ions in the solution of the entire reaction device one 1 is small, which improves the safety of the entire reaction. The liquid inlet two of the filtering device one 2 is connected to the liquid outlet one of the reaction device one 1 by a pipeline, and the liquid outlet two of the filtering device one 2 is connected to the reaction device two 3 by a pipeline. The filtering device one 2 is used for filtering the suspension one and conveying the filtrate one to the reaction device two 3. Specifically, a conveying pump is arranged between the filtering device one 2 and the reaction device two 3, which can convey the filtered filtrate one to the reaction device two 3.

[0101] In this embodiment, the filtering device one 2 can be a plate and frame filter press. The filter residue after pressure filtration by the plate and frame filter press can be conveyed to a solidification workshop for solidification treatment, and the filter residue after solidification treatment can be sent to a landfill pool for safe landfill.

[0102] The reaction device one 1 is also connected to a feeding device 11, a liquid storage tank one 12, a liquid storage tank two 13, and a gas collection device 14. The feeding device 11 can be a closed structure, which is arranged above the reaction device one 1 and communicates with the reaction device one 1. The feeding device 11 is used for feeding waste Raney nickel into the reaction device one 1. The liquid storage tank one 12 is connected to the reaction device one 1, and the liquid storage tank one 12 is used for storing dilute sulfuric acid. Dilute sulfuric acid can be added to the reaction device one 1 through the liquid storage tank one 12. The liquid storage tank two 13 is provided with two outlets, which are respectively connected to the reaction device one 1 and the reaction device two 3. The liquid storage tank two 13 is used for storing sodium hydroxide solution. The liquid storage tank two 13 can add sodium hydroxide solution to the reaction device one 1 and the reaction device two 3, respectively. The gas collection device 14 is connected to the gas outlet of the reaction device one 1, and the gas collection device 14 is used for collecting hydrogen gas generated in the reaction device one 1.

[0103] The gas collecting device 14 comprises a connecting pipe and a pressurized collecting device 142, one end of the connecting pipe is connected with the outlet of the reaction device, the other end of the connecting pipe is connected with the pressurized collecting device 142, and an air blower 141 is installed on the connecting pipe, under the action of the air blower 141, the hydrogen generated in the reaction device 1 can quickly enter the pressurized collecting device 142, and the pressurized collecting device 142 can pressurize the entering hydrogen.

[0104] It can be understood that the reaction device 1 is also provided with a water inlet, and the water inlet is used for adding tap water into the reaction device.

[0105] It can be understood that the other end of the feeding device 11 can also be provided with a belt conveyor, and the tail end of the belt conveyor is connected with the inlet of the feeding device 11, so that in actual operation, the waste Raney nickel can be transported into the feeding device 11 through the belt conveyor, and then transported into the reaction device 1 through the feeding device 11.

[0106] The reaction device 2 3 can be a sealed tank structure, and the reaction device 2 3 is used for jointly processing the filtrate 1 and the waste hydrazine to obtain a suspension 2, and a filtering device 2 4 is used for filtering the suspension 2 to obtain a filtrate 2 and a filter residue.

[0107] The reaction device 2 3 is also connected with a liquid storage tank 3 1, and the liquid storage tank 3 1 is used for adding waste hydrazine into the reaction device 2 3.

[0108] The reaction device 2 3 is also provided with an exhaust port, and the exhaust port is used for exhausting the nitrogen generated in the reaction device 2 3.

[0109] The tank body of the reaction device 2 3 can be a double-layer structure, a cavity is arranged between the two tank bodies, and a constant-temperature water inlet and a constant-temperature water outlet are arranged on the outer tank body.

[0110] The above describes the basic principles, main features and advantages of the present application. It should be understood by those skilled in the art that the present application is not limited to the above embodiments, and the above embodiments and descriptions in the specification are only the principles of the present application, and various changes and improvements can be made without departing from the spirit and scope of the present application, and these changes and improvements all fall within the scope of the claimed present application. The protection scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A method for treating waste Raney nickel in combination with hydrazine hydrate waste water, characterized in that, It comprises the following steps: (1) the waste Raney nickel is reacted with dilute sulfuric acid to obtain a mixed solution one and hydrogen, the hydrogen is collected and stored by a collecting device, and the reaction equation is as follows: Ni+2H2SO4=NiSO4+2H2↑ 2Al+3H2SO4=Al2(SO4)3+3H2↑ Fe+H2SO4=FeSO4+H2↑ The mixed solution one comprises a nickel sulfate solution, an aluminum sulfate solution and a ferrous sulfate solution; (2) hydrogen peroxide is first added to the mixed solution one to oxidize all the ferrous ions in the mixed solution one into ferric ions; then sodium hydroxide solution is added to adjust the pH value to 3-7 to obtain a suspension one; then the suspension one is filtered to obtain a filtrate one, and the reaction equation is as follows: 2Fe 2+ + H2O2 + 2H + = 2Fe 3+ + 2H2O Fe2(SO4)3+6NaOH=2Fe(OH)3↓+3Na2SO4 Al2(SO4)3+6NaOH=2Al(OH)3↓+3Na2SO4 (3) sodium hydroxide solution is further added to the filtrate one until the pH value is 8-9, and the filtrate one after pH value adjustment is heated to 85 DEG C; hydrazine hydrate is added to the heated filtrate one, and stirring is performed for 3h to obtain a suspension two; the suspension two is filtered to obtain a filtrate two and a filter residue, the content of nickel ions in the filtrate two is less than 1mg / L; the filter residue is washed and dried to obtain the filter residue whose purity is greater than 95%; and the reaction equation is as follows: 2NiSO4+N2H4+4NaOH=2Ni↓+N2↑+4H2O+2Na2SO4 The volume ratio of the filtrate to the hydrazine hydrate is 20:1; Before step (3) is performed, the content of iron ions and aluminum ions in the filtrate one needs to be detected; when the filtrate one still contains iron ions and aluminum ions, step (2) needs to be repeated until the filtrate one of step (2) does not contain iron ions and aluminum ions.

2. The method for treating waste Raney nickel with hydrazine in wastewater as described in claim 1, characterized in that, The mass fraction of the sodium hydroxide solution added in steps (2) and (3) is 32%; And / or, the mass fraction of the hydrogen peroxide is 25%-30%; And / or, the mass fraction of the dilute sulfuric acid is 10%-30%.

3. The method for treating waste Raney nickel with hydrazine in wastewater as described in claim 1, characterized in that, The filtrate two is pumped into a sewage treatment system by a filtrate pump for biochemical treatment, so that the filtrate two can be directly discharged after reaching the discharge standard.

4. The method of claim 1, wherein the hydrazine hydrate is combined with the spent Raney nickel. The volume of the added hydrogen peroxide is 3%-5% of the volume of the mixed solution one.

5. The method of claim 1, wherein the hydrazine hydrate is combined with the spent Raney nickel. The waste Raney nickel and the dilute sulfuric acid in step (1) are reacted in a closed reaction container; before the dilute sulfuric acid is added, water needs to be added to the closed reaction container.

6. A device for combined treatment of waste Raney nickel and hydrazine hydrate waste water, characterized in that, The device is used in the method for treating waste Raney nickel by using hydrazine hydrate combination; The device is used in the method for treating waste Raney nickel by using hydrazine hydrate combination; The device comprises a reaction device one (1), a filtering device one (2), a reaction device two (3) and a filtering device two (4), the reaction device one (1) is used for treating the waste Raney nickel to obtain the suspension one; one end of the filtering device one (2) is connected with the reaction device one (1), the other end of the filtering device one (2) is connected with the reaction device two (3), the filtering device one (2) is used for filtering the suspension one and conveying the filtrate one into the reaction device two (3), the reaction device two (3) is used for jointly treating the filtrate one and the waste hydrazine hydrate to obtain the suspension two, the filtering device two (4) is connected with the liquid outlet of the reaction device two (3); the filtering device two (4) is used for filtering the suspension two to obtain the filtrate two and the residue.

7. The apparatus for combined treatment of waste hydrazine hydrate and waste Raney nickel according to claim 6, characterized in that, The reaction device one (1) is a sealed tank structure.

8. The apparatus for combined treatment of waste hydrazine hydrate and waste Raney nickel according to claim 6, characterized in that, The reaction device one (1) is further connected with a feeding device (11), a liquid storage tank one (12), a liquid storage tank two (13) and a gas collecting device (14), the feeding device (11) is communicated with the reaction device one (1), the feeding device (11) is used for feeding the waste Raney nickel into the reaction device one (1); the liquid storage tank one (12) is connected with the reaction device one (1), the liquid storage tank one (12) is used for conveying the dilute sulfuric acid into the reaction device one (1); the liquid storage tank two (13) is provided with two outlets, the two outlets are respectively connected with the reaction device one (1) and the reaction device two (3) through pipelines, the liquid storage tank two (13) is used for storing sodium hydroxide solution; the gas collecting device (14) is connected with the gas outlet of the reaction device one (1), the gas collecting device (14) is used for collecting hydrogen generated in the reaction device one (1); And / or, the reaction device two (3) is further connected with a liquid storage tank three (31), the liquid storage tank three (31) is used for adding the waste hydrazine hydrate into the reaction device two (3).

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