阅读说明：本技术 一种高钙高磷钒渣低温氯化制备高纯五氧化二钒的方法 (Method for preparing high-purity vanadium pentoxide from high-calcium high-phosphorus vanadium slag through low-temperature chlorination ) 是由 杨海涛 朱庆山 范川林 于 2018-07-06 设计创作，主要内容包括：本发明公开了一种高钙高磷钒渣低温氯化制备高纯五氧化二钒的方法,所述方法包括氧化造粒工序(1)、低温氯化工序(2)、收尘淋洗工序(3)、精馏提纯工序(4)、氧化制粉工序(5)和尾渣氧化工序(6)六个工序。本方法在氧化造粒工序加入添加剂,使钒渣中的钙转化为硅酸盐相或铝硅酸盐相,避免因钙的大量氯化造成失流。在低温氯化工序采用一氧化碳作为碳源,降低氯化温度,防止因钙、镁氯化物熔融而引起失流。在氧化制粉和尾渣氧化工序通过鼓入富氧空气实现氯气的循环利用。本发明适用于高钙高磷钒渣,具有选择性好,反应温度低,不失流,环境友好,产品附加值高等优点。(The invention discloses a method for preparing high-purity vanadium pentoxide from high-calcium high-phosphorus vanadium slag through low-temperature chlorination, which comprises six procedures, namely an oxidation granulation procedure (1), a low-temperature chlorination procedure (2), a dust collection and leaching procedure (3), a rectification purification procedure (4), an oxidation powder preparation procedure (5) and a tailing oxidation procedure (6). The method adds the additive in the oxidation granulation process, so that calcium in the vanadium slag is converted into a silicate phase or an aluminosilicate phase, and the loss of current caused by the large-amount chlorination of calcium is avoided. In the low-temperature chlorination process, carbon monoxide is used as a carbon source, so that the chlorination temperature is reduced, and the loss caused by the melting of calcium and magnesium chlorides is prevented. In the oxidation powder preparation and tailing oxidation processes, the cyclic utilization of chlorine is realized by blowing oxygen-enriched air. The method is suitable for the high-calcium high-phosphorus vanadium slag, and has the advantages of good selectivity, low reaction temperature, no loss of flow, environmental friendliness, high product added value and the like.)

1. The method for preparing high-purity vanadium pentoxide from high-calcium high-phosphorus vanadium slag through low-temperature chlorination comprises six procedures, namely an oxidation granulation procedure (1), a low-temperature chlorination procedure (2), a dust collection and leaching procedure (3), a rectification purification procedure (4), an oxidation powder preparation procedure (5) and a tailing oxidation procedure (6), and specifically comprises the following steps:

1) adding the high-calcium high-phosphorus vanadium slag and the additive into the oxidation granulation process (1) in proportion, and introducing air for oxidation granulation;

2) the material after oxidation granulation enters a low-temperature chlorination procedure (2), and carbon monoxide, industrial nitrogen, industrial chlorine and circulating chlorine are introduced to perform chlorination reaction to generate chlorination flue gas and chlorination slag;

3) the chlorinated flue gas enters a dust collection and leaching process (3) to obtain dust collection slag, leaching slurry and crude vanadium oxychloride, and the leaching slurry returns to the low-temperature chlorination process (2) for adjusting the chlorination temperature;

4) the coarse vanadium oxychloride enters a rectification purification process (4) to obtain high-purity vanadium oxychloride;

5) the high-purity vanadium oxychloride enters an oxidation powder preparation process (5), and is subjected to catalytic oxidation under the action of oxygen-enriched air and a catalyst to generate high-purity vanadium pentoxide powder and chlorine, and the chlorine is used as circulating chlorine and returns to the low-temperature chlorination process (2) to be used as a chlorinating agent;

6) and (3) chlorination slag generated in the low-temperature chlorination process (2), dust collection slag generated in the dust collection and leaching process (3), and a tailing sending oxidation process (6) are used for generating regenerated chlorine and residues under the action of oxygen-enriched air, the regenerated chlorine is returned to the low-temperature chlorination process (2) to be used as a chlorinating agent, and the residues are sent for treatment.

2. The method for preparing high-purity vanadium pentoxide from high-calcium high-phosphorus vanadium slag by low-temperature chlorination according to claim 1, wherein the high-calcium high-phosphorus vanadium slag comprises vanadium slag obtained by smelting vanadium titano-magnetite and phosphorus removal slag obtained in a wet vanadium extraction process, and the high-calcium high-phosphorus vanadium slag contains 5.0% -40% of calcium oxide, 0.1% -10% of phosphorus pentoxide and 5.0% -40% of vanadium pentoxide according to the calculated content of converted oxides.

3. The method for preparing high-purity vanadium pentoxide by low-temperature chlorination of the high-calcium high-phosphorus vanadium slag according to claim 1, wherein the additive in the oxidation granulation process (1) is a silicon-rich material containing more than 20% of silicon dioxide, the mass of the additive added is 10% -90% of that of the high-calcium high-phosphorus vanadium slag, the oxidation granulation temperature is 600-1000 ℃, and the reaction time is 60-300 min.

4. The method for preparing high-purity vanadium pentoxide by low-temperature chlorination of the high-calcium high-phosphorus vanadium slag as claimed in claim 3, wherein the silicon-rich material is one or more of quartz sand, fly ash and bauxite tailings.

5. The method for preparing high-purity vanadium pentoxide by low-temperature chlorination of the high-calcium high-phosphorus vanadium slag as claimed in claim 1, wherein in the low-temperature chlorination step (2), the chlorination reactor is a fluidized bed reactor, the chlorination temperature is 300-700 ℃, and the molar ratio of carbon monoxide to chlorine is 1.0-1.5.

6. The method for preparing high-purity vanadium pentoxide by low-temperature chlorination of the high-calcium high-phosphorus vanadium slag according to claim 1, wherein the oxidation powder preparation step (5) adopts a fluidized bed reactor, the oxidation temperature is 150-600 ℃, the catalyst is pure water, the molar ratio of the pure water to the vanadium oxytrichloride is 0.01-0.15, and the molar ratio of oxygen to the vanadium oxytrichloride in the oxygen-enriched air is 0.75-0.90.

7. The method for preparing high-purity vanadium pentoxide by low-temperature chlorination of the high-calcium high-phosphorus vanadium slag according to claim 1, wherein the tailing oxidation process (6) adopts a fluidized bed reactor, the reaction temperature is 300-1000 ℃, and the retention time is 30-180 min.

Technical Field

The invention belongs to the field of metallurgy and chemical industry, and particularly relates to a method for preparing high-purity vanadium pentoxide from high-calcium high-phosphorus vanadium slag through low-temperature chlorination.

Background

In recent years, with the rapid development of industrial technologies, the rapid development of vanadium-based energy storage materials (electrolyte of all-vanadium redox flow batteries, lithium vanadate anode materials) and high-performance vanadium-based aeroalloys (vanadium-aluminum alloys, vanadium-titanium alloys) industries has generated a huge demand for high-purity vanadium pentoxide.

The vanadium titano-magnetite is the main raw material for producing vanadium pentoxide. At present, vanadium-containing molten iron is obtained mainly through reduction smelting in industry, and vanadium slag is obtained through further blowing; then preparing industrial-grade vanadium pentoxide from the vanadium slag through the processes of sodium roasting, leaching, vanadium precipitation and calcining decomposition; the industrial grade vanadium pentoxide further removes impurities by repeated dissolution and precipitation to improve the purity. Generally, industrial vanadium-containing molten iron is blown by a converter to obtain vanadium slag and semisteel, but in order to reduce the dephosphorization burden of semisteel or to produce low-phosphorus steel and ultra-low phosphorus steel, alkaline slag formers such as lime and the like are required to be added for pre-dephosphorization while the vanadium slag is blown by the vanadium-containing molten iron, so that the low-phosphorus semisteel and the high-calcium high-phosphorus vanadium slag are obtained, wherein the mass fraction of calcium oxide is 5.0-40%, and the mass fraction of phosphorus oxide is 0.1-10%. If the process of sodium roasting-water vanadium leaching is adopted, calcium and vanadium in the vanadium slag can form water-insoluble calcium vanadate or calcium-containing vanadium bronze, so that the leaching rate of the vanadium is greatly reduced. A calcification roasting-acid leaching process is proposed for some scientific researchers of the high-calcium vanadium slag, namely limestone is used as an additive to carry out oxidation roasting, dilute sulfuric acid is used for leaching, and vanadium is directly precipitated from a leaching solution. Due to the poor acid leaching selectivity, impurities such as iron, aluminum, phosphorus, manganese, etc. enter the solution along with the vanadium during leaching. Phosphorus is a harmful element in the precipitate of vanadic leachate, and in an acidic system phosphorus and vanadium form stable and complex phospho-vanadium heteropolyacids and their salts. But also can form aluminum phosphate and iron phosphate precipitates with aluminum ions and iron ions in the solution, which can pollute the ammonium vanadate precipitate and seriously affect the proceeding of vanadium precipitation of acidic ammonium salts. In the traditional 'sodium roasting-water vanadium leaching' process, the vanadium leaching solution also needs to remove phosphorus, calcium chloride is generally adopted as a phosphorus removing agent, and a large amount of vanadium and calcium are generated into calcium vanadate in the process. The phosphorus-removing slag is also a high-calcium high-phosphorus vanadium slag and lacks an effective treatment process.

Therefore, the development of the technology for preparing high-purity vanadium pentoxide by using the high-calcium high-phosphorus vanadium slag is of great significance.

The process for extracting vanadium by chlorination draws people's attention due to the characteristics of strong chlorination selectivity and easy rectification and purification. Some technicians treat vanadium slag by adopting a chlorination process and apply for technical patents. For example, chinese patent CN101709388B discloses a process for separating vanadium by chloridizing and roasting vanadium slag, which comprises mixing vanadium slag oxidizing and roasting material, solid chlorinating agent and carbonaceous reducing agent in a certain proportion, pelletizing, and roasting in a rotary kiln to volatilize vanadium in the form of chloride, thereby achieving the purpose of separating and extracting vanadium. The process of adopting the solid chlorinating agent and combining the rotary kiln for roasting has the problems of low efficiency and being not beneficial to large-scale operation. The process does not relate to a method for preparing vanadium pentoxide by vanadium oxychloride, and is not a complete technology for preparing vanadium pentoxide. Chinese patent CN101845552B discloses a method for recovering valuable elements from vanadium slag through gradient chlorination, wherein vanadium slag, solid salt and simple substance carbon are uniformly mixed, and chlorine gas is introduced at different temperatures to perform chlorination of vanadium, iron, chromium and silicon in sequence so as to achieve the purpose of separating and enriching the elements. The process simultaneously adopts a solid chlorinating agent and a gas chlorinating agent, and has a complex flow. The process does not relate to a method for preparing vanadium pentoxide by vanadium oxychloride or vanadium tetrachloride, and is not a complete technology for preparing vanadium pentoxide. Chinese patent CN103130279B discloses a method for preparing vanadium pentoxide by using vanadium-containing substances such as vanadium slag and the like as raw materials and adopting a chlorination method, wherein vanadium pentoxide is prepared by carbon chlorination (adopting a solid chlorinating agent or a gas chlorinating agent) of the vanadium-containing substances, rectification purification, liquid phase hydrolysis or ammonium salt precipitation, drying or calcination. However, the process does not provide a technical scheme for efficiently preparing vanadium pentoxide and the like from chlorides. Moreover, the technological process of preparing vanadium pentoxide by "carbo-chlorination-purification-liquid phase hydrolysis or ammonium salt precipitation-calcination" was proposed by researchers at the state university of Iowa in the United states as early as 60 s in the 20 th century (Journal of the Less-Common Metals,1960,2: 29-35). Chinese patent CN105986126B discloses a system and a method for efficiently chloridizing and extracting vanadium from vanadium slag, and vanadium pentoxide is prepared by the technological process of carbon-matching chlorination of vanadium slag, distillation purification and gas phase hydrolysis. The process adopts a boiling chlorination technology, and has great technical advantages compared with chlorination by a solid chlorinating agent. And the vanadium pentoxide is prepared from the vanadium oxychloride by adopting a gas-phase hydrolysis process, compared with liquid-phase hydrolysis or ammonium salt precipitation, the wastewater amount is greatly reduced, and the obvious technical advantage is presented. But the vanadium slag in the process directly enters a chlorination furnace without pretreatment, so that the chlorination selectivity is reduced; in addition, in the carbon-blending chlorination process, solid carbon is used as a raw material, the reaction temperature is generally high, a large amount of harmful elements are converted into chlorides, the generated calcium chloride and the like can cause melting and flow loss to influence the operation of a fluidized bed, and meanwhile, the cost of subsequent distillation purification and chlorination residue treatment is greatly increased. The gas phase hydrolysis process can generate a large amount of vanadium-containing hydrochloric acid, and the environmental protection cost is increased.

In summary, the existing vanadium chloride extraction process presents significant technical advantages, but has some outstanding problems: (1) the chlorination selectivity is poor, when vanadium element in vanadium resource is chlorinated, other calcium, magnesium, iron, titanium, silicon and chromium can be chlorinated, the generated calcium chloride and the like can cause melting loss, the fluidized bed operation is influenced, and the difficulties of rectification purification and chlorination residue treatment are increased; (2) the existing chlorine vanadium extraction process mainly aims at common vanadium slag, and has no efficient chlorination extraction technology for high-calcium high-phosphorus vanadium slag.

Therefore, through technological innovation, the high-calcium high-phosphorus vanadium slag phase reforming is realized, the chlorination temperature is reduced, the loss of current caused by the massive chlorination of calcium is avoided, the chlorination selectivity is improved, a novel process for preparing high-purity vanadium pentoxide by a high-calcium high-phosphorus vanadium slag chlorination method is developed, and the method has important significance for realizing the clean industrial utilization of the high-calcium high-phosphorus vanadium slag.

Disclosure of Invention

Aiming at the problems, the invention aims to provide a method for preparing high-purity vanadium pentoxide by low-temperature chlorination of high-calcium high-phosphorus vanadium slag, so as to reduce the chlorination temperature and improve the chlorination selectivity. The high-purity vanadium pentoxide with the purity of more than 99 percent is called as high-purity vanadium pentoxide in the invention. The method is also suitable for producing common industrial grade vanadium pentoxide. The method is suitable for the high-calcium high-phosphorus vanadium slag, and has the advantages of good selectivity, low reaction temperature, no loss of flow, environmental friendliness, high product added value and the like.

In order to achieve the purpose, the invention adopts the following technical scheme:

the method for preparing high-purity vanadium pentoxide from high-calcium high-phosphorus vanadium slag through low-temperature chlorination comprises six procedures, namely an oxidation granulation procedure 1, a low-temperature chlorination procedure 2, a dust collection and leaching procedure 3, a rectification and purification procedure 4, an oxidation powder preparation procedure 5 and a tailing oxidation procedure 6, and specifically comprises the following steps:

1) adding the high-calcium high-phosphorus vanadium slag and the additive into the oxidation granulation process 1 in proportion, and introducing air for oxidation granulation;

2) the material after oxidation granulation enters a low-temperature chlorination process 2, and carbon monoxide, industrial nitrogen, industrial chlorine and circulating chlorine are introduced to perform chlorination reaction to generate chlorination flue gas and chlorination slag;

3) the chlorinated flue gas enters a dust collection and leaching process 3 to obtain dust collection slag, leaching slurry and crude vanadium oxychloride, and the leaching slurry returns to a low-temperature chlorination process 2 for adjusting the chlorination temperature;

4) the coarse vanadium oxychloride enters a rectification purification process 4 to obtain high-purity vanadium oxychloride;

5) the high-purity vanadium oxychloride enters an oxidation powder preparation process 5, and is subjected to catalytic oxidation under the action of oxygen-enriched air and a catalyst to generate high-purity vanadium pentoxide powder and chlorine, and the chlorine is used as circulating chlorine and returns to the low-temperature chlorination process 2 to be used as a chlorinating agent;

6) the chlorination slag generated in the low-temperature chlorination process 2, the dust collecting slag generated in the dust collecting and leaching process 3 and the tailing-sending oxidation process 6 generate regenerated chlorine and residues under the action of oxygen-enriched air, and the regenerated chlorine returns to the low-temperature chlorination process 2 to be used as a chlorinating agent and the residues are sent for treatment.

Preferably, the high-calcium high-phosphorus vanadium slag comprises vanadium slag obtained by smelting vanadium titano-magnetite and phosphorus removal slag in a wet vanadium extraction process, and the content of calcium oxide, phosphorus pentoxide and vanadium pentoxide in the high-calcium high-phosphorus vanadium slag is 5.0-40%, 0.1-10% and 5.0-40% in terms of the content of oxide.

Preferably, the additive in the oxidation granulation process 1 is a silicon dioxide-rich material containing more than 20% of silicon dioxide, the silicon dioxide-rich material can be one or more of quartz sand, fly ash and bauxite tailings, the mass of the additive added is 10% -90% of that of the high-calcium high-phosphorus vanadium slag, the oxidation granulation operation temperature is 600-1000 ℃, and the reaction time is 60-300 min.

Preferably, in the low-temperature chlorination step 2, the chlorination reactor is a fluidized bed reactor, the chlorination temperature is 300-700 ℃, and the molar ratio of carbon monoxide to chlorine is 1.0-1.5.

Preferably, the oxidation powder preparation process 5 adopts a fluidized bed reactor, the oxidation temperature is 150-600 ℃, the catalyst is pure water, the molar ratio of the pure water to the vanadium oxytrichloride is 0.01-0.15, and the molar ratio of oxygen to the vanadium oxytrichloride in the oxygen-enriched air is 0.75-0.90.

Preferably, the tailing oxidation process 6 adopts a fluidized bed reactor, the reaction temperature is 300-1000 ℃, and the retention time is 30-180 min.

Compared with the prior art, the invention has the following outstanding advantages:

(1) in the oxidation granulation process, an additive is added in proportion to carry out oxidation granulation treatment, so that the reformation of an ore phase is realized, calcium in the vanadium slag is converted into a silicate phase or an aluminosilicate phase, the loss of flow caused by the massive chlorination of the calcium is prevented, and the chlorination selectivity is improved;

(2) in the low-temperature chlorination process, carbon monoxide is used as a carbon source, the chlorination temperature is reduced, the loss of flow caused by the melting of compounds such as calcium chloride and magnesium chloride is prevented, the energy consumption is reduced, and the efficient chlorination is realized;

(3) the chlorination slag and the dust collection slag in the invention adopt an oxidation treatment process to convert most of chlorine in the slag into chlorine, thereby realizing the cyclic utilization of the chlorine and reducing the cost of raw materials and environmental protection;

(4) according to the invention, the oxidation of vanadium oxychloride is realized through oxygen-enriched air, so that high-purity vanadium pentoxide and circulating chlorine are obtained, the chlorine is recycled, and the production and environmental protection costs are greatly reduced.

The technology for preparing high-purity vanadium pentoxide by using the low-temperature chlorination method of the high-calcium high-phosphorus vanadium slag can effectively improve the chlorination selectivity, reduce the reaction temperature, realize the efficient separation from other impurities, realize the effective circulation of chlorine gas, have the advantages of high efficiency, low energy consumption, good product quality and the like, and can effectively improve the economic benefit and the social benefit of the technology for preparing the vanadium pentoxide by using the chlorination method of the vanadium slag.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention.

FIG. 1 is a schematic flow diagram of a method for preparing high-purity vanadium pentoxide by low-temperature chlorination of high-calcium high-phosphorus vanadium slag.

Reference numerals: 1. the method comprises the following steps of (1) oxidizing and granulating, 2, low-temperature chlorination, 3, dust collecting and leaching, 4, rectifying and purifying, 5, oxidizing and pulverizing, and 6, oxidizing tailings.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. It should be noted that the examples are only for illustrating the technical solutions of the present invention, and not for limiting the same.