CN1631797A - Method for extracting vanadium pentoxide from vanadium-containing spent catalyst and petroleum ash - Google Patents

Abstract

A method for abstracting vanadium pentoxide using waste catalyzer containing vanadium and ash of oil is disclosed: firstly, obtain the content of V2O5 in the waste catalyzer or ash of oil, then add superfluous Na2CO3 according to mol ratio, which are mixed and shattered to be 20-60 7 ; the mixture shattered are sent into rotary kiln to be roasting for 4-6 hours; the mixture then are agtatered and dissolved in hot water, meanwhile, add CaCl2 to clear phosphor, separate the solid and liquid by filter recover sodium vanadium and sodium molybdate; under the normal temperature, the PH value is equal to 8~9.5, add superfluous ammonium chloride into the sodium vanadium and sodium molybdate, generating 15 deposit, while sodium molybdateremains in the solution to separate vanadium and molybdenum ; the 15 is broken down to be molten V2O5, then after melt, acquiring the product. The invention has low cost of electric energy, easy melt of substance, low cost and stable quality, better than other technology, especially then V2O5 produced by vanadium.

Description

Method for extracting vanadium pentoxide by using vanadium-containing waste catalyst and petroleum ash

Technical Field

The invention belongs to the technical field of heavy metal recovery, and particularly relates to a method for extracting vanadium pentoxide by using a vanadium-containing waste catalyst and petroleum ash.

Background

Vanadium is one of the important strategic materials. The vanadium catalyst is mainly used in the departments of national defense, energy, metallurgical industry and the like, the most important application of vanadium in the chemical industry is used as a catalyst, such as heavy oil dehydrogenation, desulfurization, sulfuric acid production by a contact method, special rubber synthesis, synthesis of a plurality of organic compounds in the organic industry and the like, the vanadium catalyst is used for a period of time, and the vanadium catalyst gradually loses the catalytic action and is scrapped due to poisoning and the like to become vanadium-containing waste.

Due to the shortage of vanadium resources, the amount of spent catalyst produced worldwide is about 100 million tons per year. From the viewpoints of industrial development, metal resources, and environmental protection, it is essential to recover valuable metals and effectively utilize resources and protect the environment. In the United states and Europe, vanadium-containing waste materials are used as secondary vanadium resources for recycling. Currently, the largest recovery scale is the gulf chemical and metallurgical companies in the united states, with a processing capacity of 2 million tons per year. The annual throughput of Japan Sun mining Co., Ltd is also 1.5 ten thousand tons or more.

Seven large and medium-sized enterprises which produce vanadium products at homeneed about 18 million tons of vanadium raw materials every year, although abundant vanadium titano-magnetite exists in the Panzhihua area of China, vanadium slag recovered in the iron-making process is used as a main raw material for producing vanadium pentoxide, but the vanadium slag cannot meet the domestic requirements, and a large amount of vanadium slag is imported from south Africa every year.

The waste catalyst seriously pollutes the environment and must be recycled. At present, the amount of the waste catalyst generated in the oil refining industry in China each year is about 5-10% of the total amount of the whole world. These spent catalysts contain various metals such as platinum, palladium, ruthenium, nickel, cobalt, vanadium, molybdenum, copper, aluminum, zinc, etc. in various proportions. Although the waste catalyst contains so many metals that can be recycled, because it contains a large amount of oil, the developed countries classify the waste catalyst as a harmful solid waste and the developed countries classify it as a utilizable dangerous solid waste. In terms of treatment methods, the method is mainly to burn and bury the waste. The burning causes dioxin, and the burying occupies a large amount of land to form lasting and potential pollution. For the safe recycling of the waste catalyst, developed countries, such as gulf corporation of the united states and sun corporation of japan, started in the 70 s, and mainly recovered the metals from the waste catalysts containing vanadium, molybdenum, cobalt, nickel, etc. produced in the country by smelting, chemical engineering, etc. The starting point of developed countries is mainly to solve the problem of environmental protection, the whole process flow is huge in cost, the automation degree is higher, but the production capacity is smaller, the cost is high, the currently recycled waste catalyst accounts for about 5% of the whole waste catalyst, and the treatment of the waste catalyst in the world is mainly incineration and burial.

The oil refining industry of developed countries such as America, Japan, Europe and the like adopts an advanced 'Xueflun' oil refining technology, and an aluminum-based catalyst is used for adsorbing metals such as vanadium, molybdenum, cobalt, nickel and the like in crude oil. The vanadium-containing waste catalyst is changed into a waste catalyst after adsorption saturation and is discharged, so that the vanadium-containing waste catalyst occupies a great proportion in the oil refining industry all over the world. In addition, there is also a significant amount of metallic vanadium in the petroleum ash (since crude oil contains a significant amount of vanadium). With the gradual adoption of the snow Floren technology in the oil refining industry in China, the quality of the finished oil is in international connection, and a large amount of vanadium-containing waste catalysts are generated at the same time and need to be processed.

As is well known, the production cost of vanadium ore is between 4 ten thousand and 5 ten thousand yuan per ton, the production cost of waste catalyst is between 1.6 ten thousand and 2 ten thousand yuan per ton, the cost is reduced by more than 50 percent, and the product has good quality and no pollution.

One process for extracting vanadium is disclosed by U.S. gulf chemical company. Namely: spent catalyst and Na₂CO₃Roasting together in a multi-hearth furnace at 650-850 ℃ in an oxidizing atmosphere to ensure that vanadium and molybdenum in the waste catalyst are mixed with Na₂CO₃Reacting to form water-soluble sodium vanadate and sodium molybdate, and roasting clinkerQuenching in water, milling and leaching, separating the leaching solution containing vanadium and molybdenum from the leaching residue in a counter-current decantation circuit, adding NH₄CL makes vanadium produce ammonium metavanadate, and makes it precipitate, then make it undergo the processes of roasting, melting and tabletting so as to form V₂O₅And fusing the sheets. Adding acid into sodium molybdate left in the mother liquor to differentiate and heating to 80-85 ℃ to lead Mo to be in H form₂MoO₄·H₂Precipitating in the form of O, calcining H₂MoO₄·H₂O to MoO₃。

U.S. amax also discloses a production process: by using NaOH pressDigestion of spent catalyst to recover Mo and V from the first autoclave leach liquor and AL from the second high pressure leach of concentrated lye₂O₃And smelting the leached slag into Ni-Co matte, and recovering Ni and Co from the Ni-Co matte. The process includes adding waste catalyst into caustic alkali or sodium carbonate, extracting vanadium, molybdenum, alumina, etc. under certain pressure, treating the residue with acid, and extracting nickel, cobalt, etc. This process avoids the production of metal sulfides, but has the disadvantage that Al is responsible₂O₃The extraction rate of vanadium and molybdenum is greatly reduced, the process is long, and the operation is complex.

And the treatment process in japan in this field is: the general treatment process of vanadium-containing waste catalyst is divided into two kinds, one is to add Na into the material under a certain condition₂CO₃The sulfur substances such as V, Mo, Ni, Co and the like are converted into oxides by roasting, and the oxides are leached in an alkaline solution, and all sulfides contained in the method are decomposed at high temperature to generate metal sulfides, so that the atmosphere is polluted.

In addition, since the amount of metals to be removed in the desulfurization process is different depending on the type and composition of the spent catalyst and the type of oil to be treated, which are different from each other in manufacturers, and further, even the spent catalyst discharged from the same tower has a large difference in the amount depending on the discharge position, it is difficult to stably control the production even in consideration of recycling of such materials. The leaching rate of vanadium and molybdenum is greatly changed due to different types of waste catalysts during the roasting in a rotary kiln, and sometimes the leaching rate is reduced by 50 percent.

See Table-1

Statistical Table of Components of spent catalysts-1

Producing area	Numbering	V2O5	Mo	Ni	S	CmHn	AL2O5
								Korea (Korean) State of China	A1	24.11	1.38	3.56	6.8	25～30	Balance of
A2	16.04	1.56	2.45	4.2	25～30	Balance of
							A3		9.46	3.5	2.10	3.7	25～30	Balance of
A4	3.4	4.97	2.0	2.4	25～30	Balance of
							Average		13.25	2.85	2.55	4.2	25～30	Balance of
Medicine for curing cancer Wei (medicine for curing cancer) Specially for treating diabetes	1.	14.19	3.12	2.36		25～30									Balance of
							2.	11.38	3.47	2.97		25～30	Balance of
	3.	9.68	3.51	3.04		25～30								Balance of
							4.	7.17	3.76	3.01		25～30	Balance of
	Average	10.61	3.47	2.85		25～30								Balance of

The method is characterized in that a milled waste catalyst is burnt for 18 hours at 630 ℃ to remove C and S, then NaCL is used for roasting for 2 hours at 850 ℃ in a wet nitrogen atmosphere, boiling water is used for leaching soluble vanadium of about 82 percent and molybdenum of 82 percent, and tri-n-octylamine is used for extracting and recovering molybdenum in a solution after vanadium precipitation.

Disclosure of Invention

The invention aims to provide a method for extracting vanadium pentoxide by using a vanadium-containing waste catalyst and petroleum ash.

The purpose of the invention is realized as follows: the production method comprises the following steps: first determining V in waste catalyst or petroleum ash₂O₅In the amount of Na₂CO₃∶V₂O₅Adding Na in a molar ratio of 2-4: 1₂CO₃Uniformly mixing the materials in a mixer, and crushing the materials to 20-60 meshes for later use by a crusher; continuously feeding the crushed materials into a rotary kiln through a bin for roasting, wherein the roasting temperature is 850-900 ℃, the roasting temperature is 400-500 ℃ at the tail of the kiln, and the retention time of the materials in the rotary kiln isAbout 4 to 6 hours; the roasted material is dissolved in hot water of 80-90 ℃ while being stirred, and the concentration of the roasted material is 5kg/m³Adding CaCL₂Removing impurity phosphorus, filtering by a filter to separate solid from liquid, and recovering sodium vanadate and sodium molybdate solutions; when the pH value is 8-9.5, adding excessive ammonium chloride into a sodium vanadate and sodium molybdate solution at normal temperature to enable sodium vanadate to generate ammonium metavanadate precipitate, and leaving sodium molybdate in the solutionSo as to separate vanadium and molybdenum; putting the separated ammonium metavanadate into a flaking furnace, and decomposing the ammonium metavanadate at 800-850 ℃ to prepare molten V₂O₅And making into tablet by a tablet making furnace to obtain the finished product.

The applicant develops the project from the nineties, and now expands the production scale of vanadium pentoxide to 3000 tons/year, the recovery rate reaches more than 80 percent, and the slag contains V₂O₅Less than or equal to 1.0 percent, the roasting conversion rate of vanadium and molybdenum is more than 97 percent, the production is stable, the product quality is good, and the method is deeply favored by users.

The process flow and process conditions determined by the applicant after laboratory research and pilot test are essentially different from the process for producing vanadium pentoxide by using vanadium slag. Thus, the determination of the production process conditions of the present invention is unique in the same industry. The method has the advantages of simple production process, high production capacity, easy operation, stable index, high product quality, high vanadium pentoxide content and the like, can be used for drying and squeezing out by-products in the aspect of by-product recovery, such as molybdenum, and can effectively recover available resources without secondary pollution, treat process water and return the process water to production for recycling, thereby achieving zero emission, greatly reducing the water consumption and saving energy.

The reaction principle is as follows: after the vanadium-containing waste catalyst is crushed, proper Na is added₂CO₃Oxidizing insoluble vanadium and molybdenum compounds into metal oxides by oxidation and sodium treatment roasting, reacting with sodium and the like to generate soluble sodium vanadate and sodium molybdate, soaking the vanadium and molybdenum compounds into water solution by water, purifying the solution, and adding a proper amount of NH₄Ammonium metavanadate generated by Cl, molybdic acid generated by separating molybdenum, and preparing V by decomposing ammonium metavanadate at proper temperature₂O₅Preparation of MoO by decomposition of molybdic acid₃。

The reaction mechanism is as follows:

roasting:

leaching:

removing P:

and (3) precipitation:

and (3) decomposition:

the invention utilizes the waste catalyst to produce V₂O₅The method is characterized in that:

because the rotary kiln is adopted for industrial production, the production efficiency is improved, the cost is reduced, and the annual output V of the invention₂O₅3000 tons, normal production, stable product quality and high recovery rate. The annual treatment catalyst can reach 40000 tons.

The invention adds two procedures of premixing and crushing

According to the characteristic of large fluctuation of the content of the waste catalyst, as shown in the table-1, firstly, the pre-mixing is adopted, then the pre-mixing is smashed to achieve full mixing, the mixture enters a rotary kiln (phi 4.0 multiplied by 80M) to be roasted at the temperature of 850-900 ℃, and Na is added₂CO₃The addition amount of Na₂CO₃∶V₂O₅＝2～4∶1

The conversion rates of vanadium were all over 97%, as shown in Table-3. The particle size of the crushed material is shown in the table-2

The process is characterized in that:

after pre-mixing: the grade of V is uniform, the V content is crushed into 20-60 meshes, the oxidation speed is increased, the roasting temperature is reduced, the sulfur component in the raw material can be decomposed as low as possible in the roasting process, and the sulfur component is transferred into the solution to form Na₂SO₄The pollution to air is reduced, the production is continuous and large-scale, the daily feeding amount is 120-150T, if the materials are not crushed, the conversion rate is low, and if the combustion temperature is correspondingly increased, a large amount of SO is generated₂The pollution is caused by the emission of the waste gas into the atmosphere, and the treatment is difficult as shown in the table-5

Crushing size analysis Table-2

	+20 mesh	+40 mesh	+60 mesh	+80 mesh	+100 mesh	100 mesh to 100 mesh
							Pulverizing the raw materials	4-3	18.7	21.0	17.2	25.5	8.7
Calcine material	25.17	18.5	25	30.5

Conversion rate of roasted material and V in slag₂O₅Content statistical table

TABLE-3

Weaving machine Number (C)	Weight of the material (g)	Leaching g/l					Leaching slag (％)	Conversion rate ％
									℃	VML	PH	V2O5	AL	V2O5
		1	50	80～90℃	250	8-9	32.58								1.30	1.09	97.16
2	50							80～90℃	250	7.5-8.0	33.15	1.41	0.98	97.31
		3	50	80～90℃	250	8-9	30.21								1.01	0.87	97.05
4	50							80～90℃	250	8-9	24.39	0.73	1.21	97.86
		5	50	80～90℃	250	8.5-9	29.32								1.02	0.76	97.81
6	50							80～90℃	250	8.5-9	34.61	1.24	0.75	97.61
		7	50	80～90℃	250	8-9.5	30.55								1.46	0.85	97.56
8	50							80～90℃	250	9-9.5	34.11	0.95	0.82	97.81
		9	50	80～90℃	250	9-9.5	37.27								1.86	0.84	97.54
10	50							80～90℃	250	8.5-9	35.69	1.49	0.86	97.68

In the table, the materials are analyzed to obtain the results of the production line in different grades

TABLE-4

Number of batches	Number of	Roasting at DEG C	pH value	Conversion (V)	Remarks for note
						A	10T	850～900	8～9.5	97.08
II	8T		8～9.5	97.1
						III	11T		8～9.5	97.5
Fourthly	9T		8～9.5	97.1
						Five of them	10T		8～9.5	97.48

Relationship between raw material particle size and roasting temperature

TABLE-5

Particle size of material	Calcination (. degree.C.)	Time of calcination	V conversion (%)	S(％)
					Primary particle size Φ2-3×5-6m/m	850-900	4h	85	2.0
850-1000	4h	93	0.7
				Pulverizing into 20-60 mesh powder		850-900	4h	97.7	2.0

The leached slag of the material crushed to 20 meshes before roasting is easy to wash, and the slag contains V₂O₅Less than or equal to 0.96 percent; the roasted and crushed material is about-100 meshes and is not easy to wash, and V in the slag₂O₅The recovery rate is influenced by more than or equal to 1.5 percent.

Primary phosphorus removal in the leaching process: the pH value of roasting is controlled, so that the aluminum/vanadium content of the material is controlled to be less than or equal to 0.05 during leaching, a production process is simplified, the production period is greatly shortened, the equipment setting is reduced, the investment is saved, and the recovery rate of vanadium and molybdenum can be stably improved.

The device and the occupied area are saved, the production process is simplified, the operation is convenient, the energy is saved, and the secondary heating is avoided. The P in the leaching solution is generally 1-2g/L, the temperature of the leaching solution is 80-90 ℃, and after 30 minutes, the CaCL is added₂Adding into a reaction tank, reacting with P to generate Ca₃(PO₄)₂Precipitation, separation with the leached residue, operation processThe sequence is simplified, secondary heating is prevented, steam is saved, equipment investment and occupied area are reduced, and the problem that fine mud is difficult to filter is solved.

The product quality is as follows:

v produced with spent catalyst₂O₅The stable quality of the product is well received by domestic and external users. The product analysis results are shown in Table-6

Product quality statistics Table-6

		V2O5	Si	Fe	P	As	S	Na2o+K2O	Appearance of the product
										GB 3285-87	Metallurgy of	99.0	0.15	0.20	0.03	0.01	0.01	1.0	Sheet-like shape
Chemical engineering	98.0	0.25	0.30	0.05	0.03	0.03	1.5	Sheet-like shape
									Book (I) Hair-like device Ming dynasty Raw material Product produced by birth		99.37	0.13	0.084	0.022	≤0.01	0.01	＜0.3	Sheet-like shape Metal High gloss
99.24	0.13	0.074	0.009	≤0.01	0.0071	＜0.3
							98.69	0.13			0.068	0.012	≤0.01	0.0053	＜0.3
99.00	0.12	0.074	0.009	≤0.01	0.008	＜0.3
							99.47	0.09			0.074	0.014	≤0.01	0.0088	＜0.3
99.59	0.11	0.065	0.12	≤0.01	0.0071	＜0.3
							98.90	0.12			0.055	0.023	≤0.01	0.0053	＜0.3
99.08	0.16	0.096	0.0	≤0.01	0.0040	＜0.3

The method has the advantages of low power consumption, easy melting, low consumption and stable product quality in the ferrovanadium refining process, and is superior to vanadium pentoxide produced by vanadium slag. The market prospect is good, and especially the competitive advantage on the price is that the vanadium pentoxide produced by adopting other raw materials (vanadium slag) is hopeful to be inaccessible.

Main technical and economic indicators

(1) Annual yield of 3,000 tons of vanadium pentoxide and 1,500 tons of molybdenum trioxide

(2) The product percent of pass is more than or equal to 99 percent

(3) The recovery rate can reach 80 percent

(4) The consumption of raw materials and auxiliary materials and unit consumption (see table 7).

Raw and auxiliary material dosage and unit consumption table-7

Raw materials	Specific consumption (T) V2O5(12.5％)	Total volume (year)
			Raw materials	9.86	49,300T
Soda ash	3.55	10650T
			Ammonium chloride	2.62	7860T
Coal (coal)	4.0	12000T
			Electric power	1,000	300 ten thousand DEG C
Water (W)	20.0	6.0 ten thousand meters3

As the cost is 20,000 yuan/ton lower than that of similar enterprises (using vanadium ore for production), the economic benefit is brought to the enterprises no matter the international and domestic market price changes.

The waste catalyst is utilized for production, the waste is changed into valuable, and the social benefit is remarkable.

Solving the problem of vanadium resource shortage in domestic market.

Process features of the invention

The raw materials are premixed and crushed to about 20-60 meshes before roasting, the method is suitable for large-scale production, and the conversion rate can reach 97% at the roasting temperature of 850-900 ℃.

The pH value of the roasting material is controlled, so that the chemical treatment process is simplified, the investment is saved, the cost is reduced, and the recovery rate can be improved by 2-3%.

The influence of harmful impurities P in the materials separates the materials in leaching, simplifies the operation, avoids the trouble of secondary heating, saves energy and improves the filtering speed.

Compared with the production process flows of the United states and Japan. See Table 8 for details

TABLE 9

Process conditions	Japanese	United states of America	The invention
				Pulverizing before roasting	Is free of	Is free of	Powder
Roasting equipment	Self-made furnace	Multi-chamber	Rotary kiln
				Treatment method	Is interrupted by	Is interrupted by	Continuous
Throughput of treatment	1.5T/6h		100T/day
				Conversion rate of vanadium and molybdenum	≥95％		≥97％

Drawings

FIG. 1 is a schematic view of a production process of the present invention

Detailed Description

The present invention will be further described by way of examples with reference to the accompanying drawings, but the following examples are only illustrative of the present invention and do not represent the scope of the present invention defined by the claims.

Example (b):

1. pre-mixing materials: firstly, determining V in the waste catalyst or petroleum ash₂O₅The molar ratio of the raw materials in the formula of the production process is Na₂CO₃∶V₂O₅2-4: 1, and adding Na₂CO₃Simultaneously adding a proper amount of NaCl (auxiliary material) and Na₂CO₃The weight portion ratio of the NaCl and the NaCl is 1: 0.1-0.2, so as to reduce the temperature of sodium treatment roasting, and the materials are discharged after being mixed in a mixer; the materials are conveyed into a storage bin by a belt conveyor for crushing;

2. crushing: crushing the vanadium-containing waste material to 20-40 meshes by using a hammer crusher, and putting the powder into a storage bin for later use;

3. sodium treatment roasting: the purpose of sodium roasting is to sodium-convert insoluble vanadium compounds into soluble sodium vanadate for leaching and extracting vanadium pentoxide. The crushed materials continuously enter the rotary kiln for roasting through a lifter and a feeding bin. The roasting temperature is 850-900 ℃, the kiln tail is 400-500 ℃, the retention time of the materials in the rotary kiln is about 4-6 hours, the heat source is coal gas, and the pH value of the roasted materials is 8-9.5;

4. leaching: the leaching is to dissolve sodium vanadate and sodium molybdate in the roasting clinker in hot water at 80-90 ℃ by utilizing the chemical property that the sodium vanadate and the sodium molybdate are dissolved in the water, so that the sodium vanadate and the sodium molybdate are fully dissolved in the solution, and meanwhile, the concentration is 5kg/m³Adding CaCL₂Removing impurity phosphorus, filtering by a drum filter to carry out solid-liquid separation, and recovering sodium vanadate and sodium molybdate solution for the precipitation process. The procedure filters the waste residue for additional treatment;

5. purifying: carrying out solid-liquid separation on the slurry containing suspended matters by using a plate-and-frame filter press to ensure that the clarity reaches the first level;

6. and (3) precipitation: the precipitation is to add ammonium chloride into the qualified sodium vanadate and sodium molybdate solution obtained in the purification process at normal temperature when the pH value is 8-9.0, wherein the addition amount of the ammonium chloride is 2-3 times of the molar amount of vanadium pentoxide, so that the sodium vanadate is generated into ammonium metavanadate precipitate, and the sodium molybdate is left in the solution to achieve vanadium-molybdenum separation;

7. fusing sheet: putting ammonium vanadate into a tabletting furnace, and decomposing the ammonium vanadate at 800-850 DEG CTo obtain molten V₂O₅And making into tablet by a tablet making furnace to obtain the finished product.

Example 1 Charge 8.2T (spent catalyst) containing V₂O₅: the 13% conversion was 97.6%

Production process	Premixing	Pulverizing	Roasting	Leaching out	Purification	Precipitation of	Fuse piece	Total of
									Is thrown in V2O5(T)	1.06	1.05	1.04	1.023	0.96	0.903	0.885	1.06
Output of V2O5(T)	1.05	1.04	1.023	0.96	0.903	0.885	0.849	0.849
									The recovery rate is high	99.0	99.0	98	94.1	94.1	98	96	80.1

Example 2 Charge 8.7T (spent catalyst) containing V₂O₅13.2% conversion 97.2%

Production process	Premixing	Pulverizing	Roasting	Leaching out	Purification	Precipitation of	Fuse piece	Total of
									Is thrown in V2O5(T)	1.148	1.137	1.126× 97.2％ ＝1.064	1.077	1.023	0.960	0.950	1.148
Output of V2O5(T)	1.137	1.126	1.077	1.023	0.960	0.950	0.920	0.920
									The recovery rate is high	99.0	99.0	98.5	94.9	93.8	99.0	96.8	80.1

In addition, recovery of molybdenum:

1. separation of NH₄VO₃The subsequent mother liquor is treated with H at normal temperature₂SO₄When the pH is adjusted to 1.5 to 2.5, a small amount of molybdic acid is precipitated and separated by a filter. The acid solution enters into ion exchange, molybdenum ions are absorbed, the discharged mother solution contains less than 50mg/l of Mo, and the mother solution is transferred into a process water treatment device. If the Mo content of the discharged liquid is more than 50mg/l, ions are generatedThe exchange is saturated and stopped for further processing.

2. Saturated with NH after ion exchange₄OH eluting Mo, then H₂SO₄Acidifying, circulating to the aboveAnd (5) operating.

3. Eluted NH containing molybdenum₄And (3) adding acid into the OH solution with the Mo concentration of 80-120 g/l for precipitation separation to generate ammonium molybdate, and filtering and dehydrating to obtain the product. The filtrate is returned to ion exchange for reprocessing.

4. And heating ammonium molybdate in a reflecting furnace to 400-500 ℃ for deamination, dehydration andoxidation to generate molybdenum trioxide.

Example 3 Charge 100 grams (Ash) V₂O₅20.1% conversion 97.8%

Production process	Mixing material	Roasting	Leaching out	Purification	Precipitation of	Tabletting	Total of
								Is thrown in V2O5(gram)	21	20.97× 97.8％ ＝20.12	20.12	19.12	18.28	18.1	21
Output of V2O5(gram)	20.79	20.12	19.12	18.28	18.1	17.7	17.7
								The recovery rate is high	99	99	95	95.6	99	98	84.2

Claims (5)

1. A method for extracting vanadium pentoxide by using vanadium-containing waste catalyst and petroleum ash comprises the following steps: first determining V in waste catalyst or petroleum ash₂O₅In the amount of Na₂CO₃∶V₂O₅Adding Na in a molar ratio of 2-4: 1₂CO₃Uniformly mixing the materials in a mixer, and crushing the materials to 20-60 meshes for later use by a crusher; continuously feeding the crushed materials into a rotary kiln through a bin for roasting, wherein the roasting temperature is 850-900 ℃, the roasting temperature is 400-500 ℃, and the retention time of the materials in the rotary kiln is about 4-6 hours; the roasted material is dissolved in hot water of 80-90 ℃ while being stirred, and the concentration of the roasted material is 5kg/m³Adding CaCL₂Removing impurity phosphorus, filtering by a filter to separate solid from liquid, and recovering sodium vanadate and sodium molybdate solutions; when the pH value is 8-9.5, adding excessive ammonium chloride into a sodium vanadate and sodium molybdate solution at normal temperature to enable sodium vanadate to generate ammonium metavanadate precipitate, and leaving sodium molybdate in the solution to achieve vanadium-molybdenum separation; putting the separated ammonium metavanadate into a flaking furnace, and decomposing the ammonium metavanadate at 800-850 ℃ to prepare molten V₂O₅And making into tablet by a tablet making furnace to obtain the finished product.

2. The method for extracting vanadium pentoxide according to claim 1, characterized in that: after adding Na₂CO₃Simultaneously adding a proper amount of NaCl and Na₂CO₃The weight portion ratio of the NaCl and the NaCl is 1: 0.1-0.2.

3. The method for extracting vanadium pentoxide according to claim 1, characterized in that: the mesh number of the crushed material of the hammer crusher is preferably 20-40 meshes.

4. The method for extracting vanadium pentoxide according to claim 1, characterized in that: and adding ammonium chloride into the sodium vanadate and sodium molybdate solution in an amount which is 2-3 times of the molar amount of vanadium pentoxide.

5. The method for extracting vanadium pentoxide according to claim 1, characterized in that: after removing impurity phosphorus, filtering by a rotary drum filter to carry out solid-liquid separation, and recovering sodium vanadate and sodium molybdate solution; and then carrying out solid-liquid separation on the slurry containing the suspended matters by using a plate-and-frame filter press, and combining the filtrate to obtain a mixed solution of the recovered sodium vanadate and the recovered sodium molybdate.

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