Method for extraction and separation of vanadium and nickel from petroleum coke combustion products

Abstract

The application belongs to the field of solid waste application, and relates to the field of valuable resource recovery of petroleum coke combustion product solid waste. In view of the problem that nickel and vanadium are difficult to recover due to the special physicochemical characteristics of the petroleum coke combustion product, the application innovatively adopts solution a containing M2CO3 to perform the first-stage reaction, and then solution b is used to perform the second-stage reaction, so that the combination of the two-stage treatment ideas and process parameters can realize synergy, and the efficient recovery of vanadium and nickel can be realized based on a new action mechanism. It is found that the recovery rates of vanadium and nickel can both exceed 96 % by using the process of the application, which is significantly ahead of the existing level.

Description

Technical Field

[0001] This invention belongs to the field of solid waste utilization, specifically relating to the recovery of valuable resources from petroleum coke combustion products. Background Technology

[0002] Petroleum coke is a combustible black solid obtained from delayed coking of petroleum residue and petroleum asphalt in the petroleum industry. It is characterized by high calorific value and low ash content, and is commonly used as fuel. When petroleum coke is mixed with low-calorific-value materials such as coal, sludge, coal shale, and ash, and burned at 1000-1500℃ to generate electricity, a large amount of petroleum coke residue and petroleum coke ash are produced; both are combustion products of petroleum coke. The main components of petroleum coke residue and petroleum coke ash are similar, except that petroleum coke ash particles are finer. Both petroleum coke residue and petroleum coke ash are complex materials containing elements such as vanadium, nickel, silicon, aluminum, calcium, and iron. The vanadium content is generally 2-35% (based on V₂O₅), and the nickel content is 1-8% (based on Ni).

[0003] Although petroleum coke combustion products contain considerable valuable components such as vanadium and nickel, their unique origin makes efficient recovery difficult. The main challenges are: (a) Vanadium coexists in multiple valence states (V(III), V(IV), V(V)), and the properties of different valence states of V vary significantly, making it difficult to standardize recovery behavior and achieve efficient recovery; (b) Vanadium in petroleum coke combustion products often forms highly stable phases such as calcium vanadate and nickel vanadate with nickel and calcium, making their recovery under normal pressure extremely difficult; (c) The petroleum coke combustion products are produced at temperatures exceeding 1,000 degrees Celsius. Due to the high temperature, the phase components in the waste will be mutually dissolved and intercalated, further increasing the difficulty of recovery.

[0004] Due to the special properties of petroleum coke combustion products, the valuable components are difficult to recover, and there is no effective solution in the industry. The few recovery methods available have low recovery rates for nickel and vanadium, which are difficult to meet the requirements for industrial production. For example, patent CN112941330B discloses a method for treating petroleum coke ash, which utilizes the acidic properties of water leaching of flue dust to leach vanadium and nickel; however, research shows (Chemical Engineering, 2021, 49(12):7) that the leaching rates of vanadium and nickel in water leaching of petroleum coke ash are only 60.47% and 71.67%, respectively; and the nickel leaching rate in sulfuric acid solution leaching cannot exceed 75%.

[0005] In summary, there is currently no effective solution in the industry to address the difficulty in recovering vanadium and nickel due to the physicochemical characteristics of petroleum coke combustion products. Summary of the Invention

[0006] To address the problem of the difficulty in effectively recovering vanadium and nickel from petroleum coke combustion products, the primary objective of this invention is to provide a method for extracting vanadium and nickel from petroleum coke combustion products, aiming to improve the recovery rate of vanadium and nickel from petroleum coke combustion products.

[0007] The second objective of this invention is to provide a method for extracting and separating vanadium and nickel from petroleum coke combustion products, with the aim of extracting and separating vanadium and nickel from petroleum coke combustion products.

[0008] To address the problem of the difficulty in efficiently recovering vanadium and nickel due to the physicochemical and structural characteristics of petroleum coke combustion products, this invention provides the following technical solution:

[0009] A method for extracting vanadium and nickel from petroleum coke combustion products involves pre-processing the petroleum coke combustion products in solution a, followed by separation to obtain a first-stage slag and a first-stage solution enriched with vanadium; wherein solution a is a solution containing M2CO3; and M is Na and / or K.

[0010] The first stage of slag is then subjected to a second stage reaction in solution b, and subsequently separated to obtain a second stage of slag and a second stage solution enriched with nickel and the remainder vanadium; solution b is an aqueous solution containing dissolved acidic substances.

[0011] To address the challenges of simultaneous extraction of vanadium due to its multivalent nature and the difficulty in extraction due to the solidification of vanadium and nickel in petroleum coke combustion products, this invention innovatively employs an M2CO3 solution for the first stage reaction. This dissolves and transforms the high-valence vanadium, disrupting the solid solution structure and intercalation structure of the petroleum coke combustion products. Combined with the second stage reaction in solution b, this not only synergistically improves nickel extraction but also facilitates the redox reaction of low-valence vanadium and residual high-valence vanadium in the acidic system of the first-stage slag, further enhancing vanadium extraction. This invention achieves synergy through the combination of the first stage reaction in solution a and the second stage reaction in solution b, as well as the composition and sequence of solution a and solution b, thus solving the problem of difficult vanadium and nickel recovery caused by the physicochemical structural characteristics of petroleum coke combustion products.

[0012] In this invention, the petroleum coke combustion products can be petroleum coke residue and / or petroleum coke ash;

[0013] In this invention, the vanadium in the petroleum coke combustion products includes trivalent vanadium, tetravalent vanadium, and / or pentavalent vanadium; and also contains at least one of nickel vanadate and calcium vanadate;

[0014] In this invention, the particle size of the petroleum coke combustion products is ≤100 mesh.

[0015] In this invention, there are no special requirements for the vanadium and nickel content of the petroleum coke combustion products. Considering the processing value, the vanadium content is preferably not less than 0.8 wt%, and can be more than 2 to 35 wt%, and the nickel content is preferably not less than 1%, and can be more than 1 to 8 wt%.

[0016] In this invention, the combination of the first reaction involving solution a and the second reaction involving solution b, as well as the combination of components and sequence, is the key to synergistically overcoming the limitations of the physicochemical structure of petroleum coke combustion products and improving the extraction efficiency of vanadium and nickel.

[0017] In this invention, an innovative method is to use M2CO3 solution to carry out the first stage reaction of the petroleum coke combustion products. M2CO3 solution has excellent compatibility with the characteristics of petroleum coke combustion products, and can selectively recover high-valence vanadium and destroy the sintering structure (such as solid solution coating and lattice interlocking). This can yield a first stage leachate enriched with vanadium and a first stage slag enriched with nickel and containing a small amount of residual vanadium.

[0018] Preferably, solution a further contains MOH. This invention unexpectedly discovered that using M2CO3 and MOH in the first stage reaction synergistically improves the efficient and selective extraction of vanadium and facilitates controllable modification of the microstructure. This helps improve the vanadium leaching effect during the first stage reaction. Better vanadium leaching in the first stage reaction facilitates further integration with subsequent processes, enabling better vanadium-nickel extraction and separation effects with lower reagent dosages and under less stringent conditions.

[0019] There are no special requirements for the molar ratio of M2CO3 and MOH. For example, it can be 1:0.5 to 5, or even 1:0.5 to 1.

[0020] In this invention, the concentration of the solute in solution a is not particularly required, for example, it can be 10 g / L to 400 g / L;

[0021] In this invention, the concentration of the solute in solution a is not less than the theoretical amount required to completely react vanadium, aluminum, and silicon in the petroleum coke combustion products. Considering cost considerations, it can be 1 to 10 times the theoretical amount, and more specifically, 1 to 2 times. That is, the ratio of the molar amount of Na in solution a to the total molar amount of vanadium, aluminum, and silicon in the petroleum coke combustion products is 1 to 10:1.

[0022] In this invention, during the first reaction stage, the solid-liquid ratio of the petroleum coke combustion products and solution a is 1:1.5 to 10 g / mL;

[0023] In this invention, the temperature of the first stage reaction is at or below the atmospheric boiling point of solution a. Considering the processing cost, it can be 20-105℃, and more specifically 70-105℃.

[0024] In this invention, the reaction time of the first stage is more than 0.5 hours, and considering the processing efficiency, it can be further extended to 1 to 5 hours;

[0025] In this invention, after the first stage of reaction, a first stage of residue and a first stage of solution are obtained by solid-liquid separation through filtration or centrifugation.

[0026] In this invention, by modifying and innovating the first stage reaction, and further cooperating with the second stage reaction of solution b, a synergistic effect can be achieved to improve the recovery rate of nickel. Moreover, it can also synergistically improve the recovery effect of residual vanadium.

[0027] In this invention, the acidic substance in solution b is at least one of hydrochloric acid and sulfuric acid;

[0028] In this invention, there are no special requirements for the concentration of the acidic substance in solution b, for example, it is 0.5 mol / L to 10 mol / L;

[0029] Preferably, the pH of the system at the endpoint of the second reaction stage is not higher than 2;

[0030] In this invention, the temperature of the second stage reaction is at or below the atmospheric boiling point of solution b. Considering the processing cost, it can be 20-105℃; further, it can be 20-80℃.

[0031] In this invention, the reaction time of the second stage is more than 0.5 hours, and considering the processing efficiency, it can be further extended to 1 to 5 hours;

[0032] In this invention, after the second stage reaction, the second stage residue and the second stage solution are obtained by solid-liquid separation through filtration or centrifugation.

[0033] In this invention, based on the existing forms of vanadium and nickel in solution, a primary solution and a secondary solution are processed to recover and separate vanadium and nickel. For example, this invention provides a method for extracting vanadium and nickel from petroleum coke combustion products, using the vanadium and nickel extraction method described in this invention to obtain a primary solution and a secondary solution.

[0034] The second-stage solution was subjected to vanadium extraction treatment to obtain a nickel-containing raffinate and a vanadium-supported organic phase.

[0035] The vanadium-supported organic phase is subjected to a first back-extraction and oxidation, and then mixed with a first-stage solution to obtain a vanadium extract; or the first back-extraction and first-stage solution are mixed and oxidized together to obtain a vanadium extract.

[0036] The nickel-containing raffinate is subjected to nickel extraction (nickel extraction treatment) and a second back-extraction treatment to obtain a nickel extract.

[0037] In this invention, nickel and vanadium (mainly low-valent vanadium) are separated from a two-stage solution by an extraction method. The nickel extract can be directly used to prepare nickel products. The separated vanadium is then oxidized and mixed with a first-stage solution to prepare the desired vanadium products.

[0038] In this invention, the pH of the aqueous phase in the vanadium extraction stage is 1.5-2.5. That is, the vanadium extraction process is carried out after adjusting the pH of the second-stage solution to 1.5-2.5.

[0039] Preferably, the oil phase in the vanadium extraction stage contains a cationic extractant, preferably P204; preferably, the volume percentage of the cationic extractant is 5%-50%.

[0040] Preferably, the oil phase in the vanadium extraction stage may also contain an extraction aid, such as TBP;

[0041] Preferably, the volume percentage concentration of the extraction aid in the oil phase during the vanadium extraction stage is less than or equal to 30%, and more preferably 0-20%.

[0042] Preferably, the O / A ratio during the vanadium extraction stage is 1:5 to 5:1.

[0043] In this invention, the stripping agent in the first stripping stage is a 1-6 mol / L sulfuric acid solution.

[0044] In this invention, the vanadium-supported organic phase undergoes a first back-extraction treatment to obtain a vanadium extraction residue. This residue is then oxidized by adding an oxidant and mixed with a first-stage solution (the oxidant in the vanadium extraction residue can be used to oxidize the low-valence vanadium in the first-stage solution simultaneously), yielding a vanadium extract. Alternatively, the vanadium extraction residue and the first-stage solution are mixed and then oxidized to obtain the vanadium extract. In this invention, the oxidation treatment is sufficient to ensure that the vanadium valence state in the vanadium extract is +5.

[0045] In this invention, the O / A ratio in the first back-extraction stage is 5:1 to 1:5;

[0046] Preferably, the oxidant is at least one of NaClO3 and KClO3.

[0047] Preferably, the amount of oxidant used is not less than the theoretical amount for oxidizing low-valence V to V(V), and is preferably 1 to 5 times the theoretical amount.

[0048] In this invention, the valence state of vanadium in the vanadium extract is oxidized to +5, which helps to weaken the adsorption effect of low-valence vanadium on impurities and further facilitates the subsequent preparation of high-purity vanadium pentoxide products.

[0049] In this invention, the desired vanadium product can be prepared from the vanadium leaching solution using known methods. For example, in this invention, the vanadium extract is pretreated, followed by the addition of ammonium salts for vanadium precipitation to obtain ammonium polyvanadate. The pretreatment process includes adjusting the solution pH to 5-8, aging, and subsequent solid-liquid separation steps. An unexpected discovery in this invention is that this preferred processing technology helps to improve the purity and yield of ammonium polyvanadate.

[0050] In this invention, the aging process is either a stirring process or a settling process;

[0051] Preferably, the aging time is not less than 10 minutes, and considering the efficiency of the processing technology, it can be further extended to 30 to 90 minutes.

[0052] Preferably, the ammonium salt is at least one of ammonium sulfate and ammonium chloride;

[0053] Preferably, the ammonium salt is not less than the theoretical molar amount required to completely convert vanadium in the vanadium extract into ammonium polyvanadate, and is preferably 1 to 2 times the theoretical molar amount;

[0054] Preferably, ammonium polyvanadate is subjected to pyrolysis to obtain vanadium pentoxide;

[0055] Preferably, the pyrolysis temperature is above 400℃, and more preferably 450~600℃.

[0056] In this invention, nickel products can be obtained from nickel-containing raffinate using known methods. For example, in this invention, nickel is extracted from the nickel-containing raffinate, followed by a second back-extraction to obtain a nickel extract. In this invention, the organic phase of the nickel-containing raffinate contains 5-50 vol% of HBL110 extractant, with the remainder being a hydrophobic diluent.

[0057] Preferably, the hydrophobic diluent is at least one of sulfonated kerosene, No. 200 solvent oil, and aviation kerosene;

[0058] Preferably, after nickel extraction, a nickel-enriched supported organic phase is obtained, which is then subjected to a second back-extraction with 1-6M sulfuric acid to obtain a nickel sulfate solution; the nickel sulfate is then evaporated to obtain the nickel sulfate product.

[0059] Beneficial effects

[0060] To address the challenge of recovering nickel and vanadium due to the unique physicochemical characteristics of petroleum coke combustion products, this invention innovatively employs a solution a containing M2CO3 for the first stage reaction, followed by a second stage reaction in solution b. This two-stage processing approach, combined with specific process parameters, achieves synergistic effects, enabling highly efficient recovery of vanadium and nickel through a novel mechanism. Studies have shown that the process of this invention achieves vanadium and nickel recovery rates exceeding 96%, significantly surpassing existing levels. Detailed Implementation

[0061] The following examples are intended to illustrate the present invention, and not to further limit the scope of protection of the present invention.

[0062] In this invention, the petroleum coke combustion products can be the slag and ash formed by the conventional combustion of petroleum coke at 1000–1500°C, containing combustion components such as calcium vanadate and nickel vanadate. There are no particular requirements for the vanadium and nickel content; in the following examples, as typical cases, the vanadium content is 2–35% by weight, and the nickel content is 1–8%. Furthermore, the petroleum coke combustion products are also permitted to contain 2–15% Ca, 2–5% Fe, 1–10% Al, 1–10% Si, and 1–5% Mg.

[0063] In this invention, as a typical example, the method for separating and extracting vanadium and nickel from petroleum coke combustion products includes the following steps:

[0064] Step (1): The petroleum coke combustion products with an average particle size ≤100 mesh are mixed with solution a containing M2CO3 at a solid-liquid ratio of 1:1.5~10g / mL and stirred at 20-105℃ for 1-5 hours (first stage reaction). The solid and liquid are separated to obtain filtrate A (first stage solution) and filter residue A (first stage residue).

[0065] V₂O₅ + 6OH - =2VO4 3- +3H2O

[0066] 4VO2+2OH - =2HV2O5 -

[0067] Ni3V2O8+6OH - =2VO4 3- +3Ni(OH)2

[0068] Ca(VO3)2+CO3 2- =CaCO3 + 2VO3 -

[0069] 4VO2+12OH - +O2=4VO4 3- +6H2O

[0070] SiO2 + 2OH - =SiO3 2- +H2O

[0071] Al₂O₃ + 2OH⁻ = 2AlO₂ - +H2O

[0072] The solution a contains at least M2CO3, preferably a complex of M2CO3 and MOH. The amount of solute added is 1-10 times the amount of vanadium, aluminum, and silicon in the petroleum coke combustion products reacting with M in a molar ratio of 1:1.

[0073] Step (2): Mix filter residue A with acidic solution (solution b) at a solid-liquid ratio of 1:1.5-10 g / mL and stir at 20-105℃ for 1-5 hours (second stage reaction). After solid-liquid separation, filtrate B (second stage solution) is obtained.

[0074] 3Al2O3+18H + =6Al 3+ +9H2O

[0075] V2O3+6H + =2V 3+ +3H2O

[0076] V2O5+2H + =2VO2 + +H2O

[0077] VO2+2H + =VO 2+ +H2O

[0078] VO2 + +V 3+ =2VO 2+

[0079] Ni(OH)₂ + 2H₂ + =Ni 2+ +2H2O

[0080] NiO + 2H + =Ni 2+ +H2O

[0081] MgO + 2H + =Mg 2+ +H2O

[0082] Fe2O3+6H + =2Fe 3+ +3H2O

[0083] Fe 3+ +V 3+ +H2O=VO 2+ +Fe 2+ +2H +

[0084] In this invention, the acidic solution refers to an aqueous solution containing one or more of sulfuric acid and hydrochloric acid; the amount of acid added is 10-100% of the mass of filter residue A.

[0085] Step (3): Adjust the pH of filtrate B to 1.5-2.5 by adding alkali, and then mix it with organic phase O1 containing cationic extractant for vanadium extraction to obtain vanadium-loaded organic phase O1' and raffinate C (containing nickel raffinate); organic phase O1' is subjected to first back-extraction with 1-6 mol / L sulfuric acid solution to obtain vanadium-enriched solution D and regenerated organic phase; solution D is oxidized with oxidant to obtain solution E;

[0086] The aforementioned alkali adjustment refers to adding one or more of sodium hydroxide, sodium carbonate, sodium bicarbonate, calcium oxide, calcium hydroxide, and calcium carbonate, and stirring the reaction at 20-105℃ to adjust the final pH of the solution.

[0087] The cationic extractant comprises one or more of Cyanex272, P204, and P507, preferably P204;

[0088] Preferably, the organic phase O1 also contains a diluent;

[0089] Preferably, the diluent is at least one of sulfonated kerosene, No. 200 solvent oil, and aviation kerosene;

[0090] Preferably, the volume content of P2O4 in the organic phase O1 is 5-50%.

[0091] The organic phase O1 also contains the extractant TBP, which has a volume content of less than or equal to 30%.

[0092] Preferably, in the organic phase O1, the volume percentage concentration of P2O4 is 5%-50%; the volume percentage concentration of the extraction aid TBP is 0%-30%, and the remainder is a diluent.

[0093] Preferably, the oxidant is NaClO3.

[0094] Step (4): Add solution E to filtrate A and stir to adjust the pH of the solution to 5-8. Stir to react, let stand, filter, and obtain solution F. Then, use the acidic ammonium salt method to precipitate the ammonium polyvanadate product.

[0095] The stirring reaction and standing time mentioned above refer to stirring the reaction at 20-105℃ for 5-30 minutes and standing for no less than 30 minutes.

[0096] Step (5): The nickel in the raffinate C is directly extracted and separated by organic phase O2 containing extractant HBL110 to obtain nickel-loaded organic phase O2'; the loaded organic phase O2' is back-extracted by 1-6 mol / L sulfuric acid solution to obtain purified nickel sulfate solution, and then nickel sulfate product is precipitated by evaporation crystallization method.

[0097] In the organic phase O2, the volume content of HBL110 is 5-50%, and the balance is at least one of sulfonated kerosene, No. 200 solvent oil, and aviation kerosene as a diluent.

[0098] The following is a typical example:

[0099] Example 1

[0100] Leaching process:

[0101] Step (1): Take 1000g of petroleum coke containing 2% vanadium (V2O5), 1% nickel, 10% aluminum, 5% silicon, 3% magnesium, and 2% calcium, grind it to 100 mesh, mix it with sodium carbonate solution at a solid-liquid ratio of 1:1.5g / mL (the molar ratio of Na in sodium carbonate to the total molar ratio of vanadium, aluminum, and silicon in petroleum coke is 2:1), stir and react at 105℃ for 1 hour, separate the solid and liquid, and obtain filtrate A1 and filter residue A1;

[0102] The vanadium leaching rate in this step was 88.6%, and the nickel leaching rate was 0.01%.

[0103] Step (2): The filter residue A1 was mixed with a sulfuric acid solution (the amount of sulfuric acid added was 10% of the amount of filter residue A1) at a solid-liquid ratio of 1:1.5 g / mL and stirred at 60°C for 3 hours. The solid and liquid were separated to obtain filtrate B1. The vanadium leaching rate of this step was 10.8% and the nickel leaching rate was 99.2%. Combining steps 1 and 2, the total vanadium leaching rate reached 99.4% and the nickel leaching rate was 99.2%.

[0104] Extraction and separation process:

[0105] Step (3): Add sodium hydroxide to filtrate B1 to adjust the pH of the solution to 1.5, then mix it with organic phase O1 composed of 5% P2O4 + 10% TBP + 85% sulfonated kerosene for vanadium extraction; the O / A ratio of the extraction process is 1:5, and the number of extraction stages is 6. Obtain vanadium-loaded organic phase O1' and raffinate C1; organic phase O1' is back-extracted with 1 mol / L sulfuric acid solution, and the O / A ratio of the back-extraction process is 5:1 to obtain vanadium-enriched solution D1; solution D1 is oxidized with NaClO3 to obtain solution E1;

[0106] Step (4): Add solution E1 to filtrate A1 with stirring to adjust the pH of the solution to 5. Then, stir the reaction at 105℃ for 5 min, let it stand (age) for 90 min, and then filter to obtain solution F1. Then, precipitate the ammonium polyvanadate product using the acidic ammonium salt method. The ammonium polyvanadate is pyrolyzed at 500℃ for 6 hours to obtain vanadium pentoxide product with a purity of 99.4%.

[0107] Step (5): Extraction separation of raffinate C1 and organic phase O2 composed of 5v% HBL110 + 95v% sulfonated kerosene was carried out to obtain nickel-loaded organic phase O2'; the loaded organic phase O2' was back-extracted with 1mol / L sulfuric acid solution to obtain purified nickel sulfate solution, which was then evaporated and crystallized to obtain nickel sulfate product, the quality of which met the Class I standard of GB / T 26524-2011.

[0108] The vanadium recovery rate was 96.4% and the nickel recovery rate was 96.1% throughout the process.

[0109] Comparative Example 1

[0110] Compared with Example 1, the only difference is that step 1 is not performed. Specifically:

[0111] 1000g of petroleum coke residue (same as in Example 1) was ground to 100 mesh and mixed with a sulfuric acid solution (the amount of sulfuric acid added was 10% of the mass of the petroleum coke residue) at a solid-liquid ratio of 1:1.5g / mL. The mixture was stirred and reacted at 60°C for 3 hours. After solid-liquid separation, a filtrate containing vanadium and nickel was obtained. The vanadium leaching rate was 39.1%, and the nickel leaching rate was 38.6%. This is significantly better than the 99.4% total vanadium leaching rate and 99.2% nickel leaching rate in Example 1.

[0112] Comparative Example 2

[0113] Compared with Example 1, the difference is that step 1 is not performed, the acid leaching time is the sum of the alkali leaching and acid leaching times in Example 1, and the leaching temperature is 105°C, specifically:

[0114] Take 1000g of petroleum coke residue (same as in Example 1), grind it to 100 mesh, mix it with a sulfuric acid solution (the amount of sulfuric acid added is 10% of the mass of petroleum coke residue) at a solid-liquid ratio of 1:1.5g / mL, stir and react at 105℃ for 4 hours, separate the solid and liquid, and obtain a filtrate containing vanadium and nickel.

[0115] The vanadium leaching rate was 63.4% and the nickel leaching rate was 43.2% throughout the process. This is significantly better than the vanadium leaching rate of 99.4% and the nickel leaching rate of 99.2% in Example 1.

[0116] A comparison of Example 1 and Comparative Examples 1-2 shows that even with increased temperature and leaching time, the leaching rates of vanadium and nickel are not irrational when using a single step 2.

[0117] Comparative Example 3

[0118] Compared to Example 1, the only difference is that solution a contains only sodium hydroxide solution, specifically:

[0119] Step (1): Take 1000g of petroleum coke residue (same as in Example 1), grind it to 100 mesh, mix it with sodium hydroxide solution (sodium hydroxide and sodium carbonate in Example 1 have the same molar amount of sodium) at a solid-liquid ratio of 1:1.5g / mL, stir and react at 105℃ for 1 hour, separate the solid and liquid, and obtain filtrate A1 and filter residue A1; in this leaching process, the vanadium leaching rate is 73.2% and the nickel leaching rate is 1.6%; compared with the total vanadium leaching rate of 99.4% and the nickel leaching rate of 99.2% in Example 1, the difference is obvious.

[0120] Comparative Example 4

[0121] Compared to Example 1, the difference lies in that the petroleum coke residue is first treated with acidic solution b and then with solution a, specifically:

[0122] 1000g of petroleum coke residue (same as in Example 1) was ground to 100 mesh and mixed with a sulfuric acid solution (the amount of sulfuric acid added was 10% of the mass of the petroleum coke residue) at a solid-liquid ratio of 1:1.5g / mL. The mixture was stirred and reacted at 60°C for 3 hours. After solid-liquid separation, filtrate containing vanadium and nickel and filter residue A1 were obtained. (Vanadium leaching rate was 39.1%, and nickel leaching rate was 38.6%)

[0123] The filter residue A1 was mixed with sodium carbonate solution (same as in Example 1) at a solid-liquid ratio of 1:1.5 g / mL and stirred at 105°C for 1 hour. The solid and liquid were then separated to obtain filtrate and filter residue A2. (Vanadium leaching rate was 43.6%, and nickel leaching rate was 0.05%)

[0124] In steps (1) and (2), the total vanadium leaching rate was 82.7%, and the nickel leaching rate was 38.6%. This is significantly better than the total vanadium leaching rate of 99.4% and the nickel leaching rate of 99.2% in Example 1.

[0125] Example 2

[0126] Compared to Example 1, the only difference is that filtrate A was not mixed with solution E. Specifically:

[0127] Step (1): Take 1000g of petroleum coke residue (same as in Example 1), grind it to 100 mesh, mix it with sodium carbonate solution (the ratio of the molar amount of Na element to the total molar amount of vanadium, aluminum and silicon in petroleum coke residue is 2:1) at a solid-liquid ratio of 1:1.5g / mL, stir and react at 105℃ for 1 hour, separate the solid and liquid, and obtain filtrate A1 and filter residue A1;

[0128] Acid was added to filtrate A1 to adjust the pH to 5, and the solution was stirred at 105℃ for 5 min, allowed to stand (age) for 90 min, and then filtered. Ammonium polyvanadate was then precipitated using the acidic ammonium salt method. The polyvanadate was pyrolyzed at 500℃ for 6 hours to obtain vanadium pentoxide with a purity of 81.6%. Filtrate A1 contains tetravalent vanadium, which has a stronger impurity adsorption capacity than pentavalent vanadium. If it is not pre-mixed with solution E and the oxidizing components in solution E are not utilized to increase the valence state, the purity of the final vanadium will decrease.

[0129] Example 3

[0130] Step (1): Take 1000g of a mixture of petroleum coke residue and petroleum coke ash containing 15% vanadium (V2O5), 6% nickel, 5% aluminum, 7% silicon, 4% magnesium, and 9% calcium, grind it to 150 mesh, and mix it with a mixed solution of sodium hydroxide and sodium carbonate at a solid-liquid ratio of 1:5g / mL (the molar ratio of sodium hydroxide and sodium carbonate is 1:1, and the molar ratio of sodium element to vanadium, aluminum, and silicon in the petroleum coke residue in the mixed solution of sodium hydroxide and sodium carbonate is 6:1). Stir and react at 70℃ for 3 hours, and separate the solid and liquid to obtain filtrate A1 and filter residue A1; the vanadium leaching rate of this step is 92.2%, and the nickel leaching rate is 0.08%;

[0131] Step (2): Mix filter residue A1 with hydrochloric acid solution (the amount of hydrochloric acid added is 20% of the amount of filter residue A1) at a solid-liquid ratio of 1:6 g / mL and stir at 20°C for 5 hours. Separate the solid and liquid to obtain filtrate B1. The vanadium leaching rate of this step is 7.6% and the nickel leaching rate is 99.6%.

[0132] Combining steps 1 and 2, vanadium is mainly leached in the first step, with a total leaching rate of 99.8%, while nickel reaches 99.6%.

[0133] Step (3): Add sodium carbonate to filtrate B1 to adjust the pH of the solution to 2.0, then mix it with organic phase O1 composed of 15% P2O4 + 20% TBP + 65% sulfonated kerosene for vanadium extraction; the O / A ratio of the extraction process is 1:3, and the number of extraction stages is 6. Obtain vanadium-loaded organic phase O1' and raffinate C1; organic phase O1' is back-extracted with 3 mol / L sulfuric acid solution, and the O / A ratio of the back-extraction process is 1:5 to obtain vanadium-enriched solution D1; solution D1 is oxidized with NaClO3 to obtain solution E1;

[0134] Step (4): Add solution E1 to filtrate A1 with stirring to adjust the pH of the solution to 7. Then, stir the reaction at 60℃ for 10 min, let it stand (age) for 60 min, and then filter to obtain solution F1. Then, precipitate the ammonium polyvanadate product using the acidic ammonium salt method. The ammonium polyvanadate is pyrolyzed at 500℃ for 6 hours to obtain vanadium pentoxide product with a purity of 99.5%.

[0135] Step (5): Extraction separation of raffinate C1 and organic phase O2 composed of 25v% HBL110 + 75v% sulfonated kerosene was performed to obtain nickel-loaded organic phase O2'; the loaded organic phase O2' was back-extracted with 4mol / L sulfuric acid solution to obtain purified nickel sulfate solution, which was then evaporated and crystallized to obtain nickel sulfate product, the quality of which met the Class I standard of GB / T 26524-2011.

[0136] The vanadium recovery rate was 98.9% and the nickel recovery rate was 97.8% throughout the process.

[0137] Example 4

[0138] Compared to Example 3, the only difference is that solution a is a single sodium carbonate solution, specifically:

[0139] Step (1): Take 1000g of a mixture of petroleum coke residue and petroleum coke ash containing 15% vanadium (based on V2O5), 6% nickel, 5% aluminum, 7% silicon, 4% magnesium, and 9% calcium, grind it to 150 mesh, and mix it with a sodium carbonate mixed solution (the molar amount of sodium is the same as in Example 3) at a solid-liquid ratio of 1:5g / mL. Stir and react at 70°C for 3 hours, then separate the solid and liquid to obtain filtrate A1 and filter residue A1. The vanadium leaching rate in this step is 90.1%, and the nickel leaching rate is 0.01%, which is lower than the 92.2% leaching rate in Example 3. The better leaching of vanadium in the first step helps to further facilitate subsequent nickel extraction and nickel-vanadium separation.

[0140] Example 5

[0141] Step (1): Take 1000g of petroleum coke containing 35% vanadium (based on V2O5), 8% nickel, 10% aluminum, 10% silicon, 1% magnesium, and 2% calcium, grind it to 200 mesh, and mix it with a solution of sodium carbonate and sodium hydroxide (the molar ratio of sodium to vanadium, aluminum, and silicon in the petroleum coke is 10:1) at a solid-liquid ratio of 1:10 g / mL. Stir and react at 20℃ for 5 hours, then separate the solid and liquid to obtain filtrate A1 and filter residue A1; (vanadium leaching rate is 95.1%, nickel leaching rate is 0.09%).

[0142] Step (2): Mix filter residue A1 with a sulfuric acid solution (the amount of sulfuric acid added is 100% of the amount of filter residue A1) at a solid-liquid ratio of 1:10 g / mL and stir at 80°C for 2 hours. Separate the solid and liquid to obtain filtrate B1; (vanadium leaching rate is 4.7%, nickel leaching rate is 99.7%)

[0143] Step (3): Add calcium oxide to filtrate B1 to adjust the pH of the solution to 2.5, then mix it with organic phase O1 composed of 50% P2O4 + 50% sulfonated kerosene for vanadium extraction. The O / A ratio of the extraction process is 5:1, and the number of extraction stages is 6. This yields vanadium-loaded organic phase O1' and raffinate C1. Organic phase O1' is back-extracted using 6 mol / L sulfuric acid solution with an O / A ratio of 3:1 to obtain vanadium-enriched solution D1. Solution D1 is then oxidized with NaClO3 to obtain solution E1.

[0144] Step (4): Add solution E1 to filtrate A1 with stirring to adjust the pH of the solution to 8. Then, stir the reaction at 20℃ for 30 min, let it stand for 60 min, and then filter to obtain solution F1. Then, precipitate the ammonium polyvanadate product using the acidic ammonium salt method. The polyvanadate is pyrolyzed at 500℃ for 6 hours to obtain vanadium pentoxide product with a purity of 99.2%.

[0145] Step (5): Extraction separation of raffinate C1 and organic phase O2 composed of 50% HBL110 + 50% sulfonated kerosene is performed to obtain nickel-loaded organic phase O2'; the loaded organic phase O2' is back-extracted with 1 mol / L sulfuric acid solution to obtain purified nickel sulfate solution, which is then evaporated and crystallized to obtain nickel sulfate product, the quality of which meets GB / T 26524-2011 Class I standard.

[0146] The vanadium recovery rate was 99.0% and the nickel recovery rate was 98.5% throughout the process.

Claims

1. A method for extracting vanadium and nickel from petroleum coke combustion products, characterized in that, The petroleum coke combustion products are first reacted in solution a, and then separated to obtain a first-stage slag and a first-stage solution enriched with vanadium; wherein solution a is a solution containing M2CO3; wherein M is Na and / or K; The first stage of slag is then subjected to a second stage reaction in solution b, and subsequently separated to obtain a second stage of slag and a second stage solution enriched with nickel and the remainder vanadium; solution b is an aqueous solution containing dissolved acidic substances. The petroleum coke combustion products are formed by burning petroleum coke at 1000~1500℃, and include petroleum coke residue and / or petroleum coke ash. The petroleum coke combustion products contain vanadium in trivalent, tetravalent, and / or pentavalent states; and also contain at least one of nickel vanadate and calcium vanadate. The particle size of the petroleum coke combustion products is ≤100 mesh.

2. The method for extracting vanadium and nickel from petroleum coke combustion products as described in claim 1, characterized in that, The solution a also contains MOH.

3. The method for extracting vanadium and nickel from petroleum coke combustion products as described in claim 2, characterized in that, The molar ratio of M2CO3 to MOH is 1:0.5~5.

4. The method for extracting vanadium and nickel from petroleum coke combustion products as described in claim 1, characterized in that, In solution a, the concentration of the solute is 10~400 g / L; In solution a, the concentration of the solute is not less than the theoretical amount required to completely react vanadium, aluminum and silicon in the petroleum coke combustion products; In the first stage of the reaction, the solid-liquid ratio of the petroleum coke combustion products and solution a is 1:1.5~10 g / mL; The temperature of the first stage reaction is at or below the atmospheric boiling point of solution a; The first stage of the reaction takes more than 0.5 hours; After the first stage of reaction, solid-liquid separation by filtration or centrifugation is used to obtain a first stage of residue and a first stage of solution.

5. The method for extracting vanadium and nickel from petroleum coke combustion products as described in claim 1, characterized in that, The acidic substance in solution b is at least one of hydrochloric acid and sulfuric acid; The concentration of the acidic substance in solution b is 0.5 mol / L to 10 mol / L; The pH of the system at the endpoint of the second stage reaction is no higher than 2; The temperature of the second stage reaction is at or below the atmospheric boiling point of solution b; The second stage reaction takes more than 0.5 hours; After the second stage reaction, the solid-liquid separation method, such as filtration or centrifugation, is used to obtain the second stage residue and the second stage solution.

6. A method for extracting and separating vanadium and nickel from petroleum coke combustion products, characterized in that, A first-stage solution and a second-stage solution are obtained by using the vanadium-nickel extraction method according to any one of claims 1 to 5; The two-stage solution was subjected to vanadium extraction treatment to obtain nickel raffinate and vanadium-supported organic phase; The vanadium-supported organic phase is subjected to a first back-extraction and oxidation, and then mixed with a first-stage solution to obtain a vanadium extract; or the first back-extraction and first-stage solution are mixed and oxidized together to obtain a vanadium extract. The nickel raffinate was subjected to nickel extraction and a second back-extraction process to obtain a nickel extract.

7. The method for extracting and separating vanadium and nickel from petroleum coke combustion products as described in claim 6, characterized in that, The pH of the aqueous phase during the vanadium extraction stage is 1.5-2.5; The oil phase in the vanadium extraction stage contains a cationic extractant.

8. The method for extracting and separating vanadium and nickel from petroleum coke combustion products as described in claim 7, characterized in that, The cationic extractant is P2O4.

9. The method for extracting and separating vanadium and nickel from petroleum coke combustion products as described in claim 7, characterized in that, The volume percentage of the cationic extractant is 5%-50%.

10. The method for extracting and separating vanadium and nickel from petroleum coke combustion products as described in claim 7, characterized in that, The oil phase in the vanadium extraction stage also contains extraction aids.

11. The method for extracting and separating vanadium and nickel from petroleum coke combustion products as described in claim 10, characterized in that, The extraction aid is TBP.

12. The method for extracting and separating vanadium and nickel from petroleum coke combustion products as described in claim 10, characterized in that, The volume percentage concentration of the extraction aid in the oil phase during the vanadium extraction stage is less than or equal to 30%.

13. The method for extracting and separating vanadium and nickel from petroleum coke combustion products as described in claim 6, characterized in that, The O / A ratio during the vanadium extraction stage is 1:5 to 5:

1.

14. The method for extracting and separating vanadium and nickel from petroleum coke combustion products as described in claim 6, characterized in that, The stripping agent in the first stripping stage is a 1-6 mol / L sulfuric acid solution; The O / A ratio in the first back-extraction stage is 5:1 to 1:

5.

15. The method for extracting and separating vanadium and nickel from petroleum coke combustion products as described in claim 14, characterized in that, An oxidant is added to the vanadium back-extraction solution from the first back-extraction process to carry out oxidation treatment; The oxidant is at least one of NaClO3 and KClO3; The amount of oxidant used shall not be less than the theoretical amount required to oxidize low-valence V to V(V).

16. The method for extracting and separating vanadium and nickel from petroleum coke combustion products as described in claim 6, characterized in that, The vanadium extract was pretreated, followed by the addition of ammonium salt for vanadium precipitation to obtain ammonium polyvanadate. The pretreatment process included adjusting the solution pH to 5-8, aging, and subsequent solid-liquid separation steps.

17. The method for extracting and separating vanadium and nickel from petroleum coke combustion products as described in claim 16, characterized in that, The aging process can be either a stirring or a settling process; The aging time should be no less than 10 minutes.

18. The method for extracting and separating vanadium and nickel from petroleum coke combustion products as described in claim 16, characterized in that, The ammonium salt is at least one of ammonium sulfate and ammonium chloride; The ammonium salt is not less than the theoretical molar amount required to completely convert vanadium in the vanadium extract into ammonium polyvanadate.

19. The method for extracting and separating vanadium and nickel from petroleum coke combustion products as described in claim 16, characterized in that, Ammonium polyvanadate was pyrolyzed to obtain vanadium pentoxide; The pyrolysis temperature is above 400℃.

20. The method for extracting and separating vanadium and nickel from petroleum coke combustion products as described in any one of claims 6 to 19, characterized in that, The organic phase of the nickel extraction residual liquid stage contains 5-50 v% of HBL110 extractant, with the remainder being a hydrophobic diluent.

21. The method for extracting and separating vanadium and nickel from petroleum coke combustion products as described in claim 20, characterized in that, The hydrophobic diluent is at least one of sulfonated kerosene, No. 200 solvent oil, and aviation kerosene; After nickel extraction, a nickel-enriched supported organic phase is obtained. Then, a second back-extraction is performed using 1-6M sulfuric acid to obtain a nickel sulfate solution. The nickel sulfate is then evaporated to obtain the nickel sulfate product.