阅读说明：本技术 一种钒渣提钒协同控制尾渣中钠含量的方法 (Method for cooperatively controlling sodium content in tailings by extracting vanadium from vanadium slag ) 是由 杜浩 王少娜 刘彪 王新东 李兰杰 赵备备 王海旭 于 2020-06-15 设计创作，主要内容包括：本发明提供一种钒渣提钒协同控制尾渣中钠含量的方法,所述方法将钒渣、钙源和碱浓度45～55wt％的NaOH溶液混合后进行氧化反应,经固液分离后得到的尾渣洗涤后即可得到低钠尾渣；所述方法通过严格控制氢氧化钠溶液的浓度并组合其他工艺条件能够在保持提钒率的同时实现尾渣中钠含量的有效控制,所得尾渣中Na<Sub>2</Sub>O含量在1％以下,尾渣易于实现资源化利用。(The invention provides a method for cooperatively controlling sodium content in tailings by extracting vanadium from vanadium slag, which comprises the steps of mixing vanadium slag, a calcium source and a NaOH solution with the alkali concentration of 45-55 wt%, carrying out oxidation reaction, and washing tailings obtained after solid-liquid separation to obtain low-sodium tailings; the method can realize effective control of sodium content in tailings while maintaining vanadium extraction rate by strictly controlling the concentration of sodium hydroxide solution and combining other process conditions, and Na in the obtained tailings 2 The content of O is below 1 percent, and the tailings are easy to realize resource utilization.)

1. A method for cooperatively controlling the sodium content in tailings by extracting vanadium from vanadium slag is characterized by comprising the following steps:

(1) mixing vanadium slag, a calcium source and a NaOH solution with the mass concentration of 45-55 wt% to obtain mixed slurry;

(2) carrying out oxidation reaction on the mixed slurry obtained in the step (1) and oxidizing gas to obtain reacted slurry;

(3) and (3) carrying out solid-liquid separation on the slurry after the reaction in the step (2) to obtain tailings and vanadium-containing leaching liquid, and washing the tailings to obtain low-sodium tailings.

2. The method according to claim 1, wherein the calcium source in step (1) comprises calcium oxide and/or calcium hydroxide;

preferably, the mass concentration of the alkali in the NaOH solution is 48-52 wt%.

3. The method according to claim 1 or 2, wherein the mass ratio of the vanadium slag to the calcium source in the step (1) is 10: 1-10: 3, preferably 10: 1.5-10: 2.5;

preferably, the liquid-solid ratio of the NaOH solution to the vanadium slag is 3: 1-10: 1, and preferably 5: 1-7: 1.

4. The method according to any one of claims 1 to 3, wherein the pressure of the oxidation reaction in the step (2) is 1MPa or less;

preferably, the temperature of the oxidation reaction is 130-200 ℃, and preferably 150-180 ℃;

preferably, the time of the oxidation reaction is more than or equal to 2 h.

5. The method according to any one of claims 1 to 4, wherein the oxidizing gas in step (2) comprises oxygen and/or air.

6. The method according to any one of claims 1 to 5, wherein the slurry after the reaction in the step (3) is diluted and then subjected to solid-liquid separation;

preferably, the diluent used for dilution comprises water and/or a vanadium slag vanadium extraction process circulating liquid.

7. The method according to any one of claims 1 to 6, wherein the mass concentration of NaOH in the diluted slurry in the step (3) is 18 to 45 wt%.

8. The method according to any one of claims 1 to 7, wherein Na in the low-sodium tailings in step (3) is₂The content of O is less than or equal to 1wt percent.

9. A method according to any one of claims 1 to 8, characterized in that the method comprises the steps of:

(1) mixing vanadium slag, a calcium source and a NaOH solution with the mass concentration of 45-55 wt% to obtain mixed slurry; the mass ratio of the vanadium slag to the calcium source is 10: 1-10: 3, and the liquid-solid ratio of the NaOH solution to the vanadium slag is 3: 1-10: 1;

(2) carrying out oxidation reaction on the mixed slurry obtained in the step (1) and oxidizing gas for at least 2h under the conditions that the pressure is less than or equal to 1MPa and the temperature is 130-200 ℃ to obtain reacted slurry;

(3) carrying out solid-liquid separation on the slurry after the reaction in the step (2) to obtain tailings and vanadium-containing leaching solution, and washing the tailings to obtain Na₂Low-sodium tailings with the content of O less than or equal to 1 wt%.

10. The low-sodium tailings are characterized by being prepared by adopting the method for extracting vanadium from vanadium slag to cooperatively control the sodium content in the tailings as claimed in any one of claims 1 to 9.

Technical Field

The invention relates to the technical field of vanadium chemical metallurgy, in particular to a method for cooperatively controlling sodium content in tailings by extracting vanadium from vanadium slag.

Background

The vanadium extraction tailings are tailings generated after vanadium extraction by a vanadium slag high-temperature sodium salt roasting process in iron and steel enterprises, and the annual production amount is nearly millions of tons, wherein the tailings are rich in valuable components such as vanadium, chromium, silicon, iron, sodium and the like. The existing research at home and abroad aiming at the utilization of the vanadium extraction tailings mainly focuses on the aspects of sodium salt roasting, vanadium extraction, iron extraction by reduction, and development of added-value products such as cement base materials, ceramic materials and the like, but the sodium content in the sodium salt vanadium extraction tailings is too high, so that reinforcing steel bars in concrete are corroded, the service life of the reinforcing steel bars is shortened, the expansion application of the vanadium extraction tailings in the field of cement is limited, the consumption of the tailings in the ceramic industry is far less than the output of the tailings, and most of the vanadium extraction tailings cannot be effectively utilized. In addition, the vanadium extraction tailings have high contents of elements such as iron, vanadium, chromium, titanium, manganese and the like, and are ideal raw materials for manufacturing pellet ore by a cold consolidation method, so the vanadium extraction tailings can be added into sintered ore according to a certain proportion and return to the steel process, and large-scale consumption of the sintered ore is realized. However, in the process of sintering, if the sodium content in the vanadium extraction tailings is too high, the risk of further increasing the alkali load of the blast furnace exists, the blast furnace lining is greatly damaged, and the smooth operation of the blast furnace is influenced.

CN105671327B discloses a method for removing sodium from vanadium extraction tailings, which is characterized in that calcium additives are added into the vanadium extraction tailings generated in the traditional sodium salt roasting process under an alkaline condition, the reaction is carried out at the temperature of 80-200 ℃, and Na in the vanadium extraction tailings obtained in the traditional sodium salt roasting process can be used₂The O content is reduced to below 1 wt% from 4 wt%, the vanadium-containing tailings after sodium removal meet the requirement of being directly applied to blast furnace iron making, the problems of reduction pulverization of sintering ores, abnormal expansion of pellets and the like caused by the existence of sodium are effectively avoided, and the service life of a furnace lining of the blast furnace is effectively prolonged. The technical core of the patent lies in that sodium in the tailings in the form of sodium aluminosilicate is converted into calcium aluminosilicate through an alkaline hydrothermal reaction, so that dissociation and removal of the sodium are realized.

CN103952558A discloses a method for removing sodium from vanadium extraction tailings of vanadium titano-magnetite. The existing form of sodium in the vanadium extraction tailings of the vanadium titano-magnetite is also sodium aluminosilicate. The method comprises the following steps: adding vanadium extraction tailings of vanadium titano-magnetite into acid solution with set amount and concentration, and enabling the acid solution and the vanadium extraction tailings to react for set time at set temperature so as to remove vanadium in the vanadium extraction tailings; and separating the vanadium extraction tailings and the acid solution after the reaction is finished. The method needs to use a large amount of acid liquor, and the amount of the waste liquor after treatment is large and is difficult to treat, so that the process cost is high.

In recent years, the liquid-phase oxidation process for extracting vanadium gradually becomes a new technology of vanadium slag vanadium extraction industry, and CN102127655A discloses a method for decomposing vanadium slag by NaOH solution at normal pressure, wherein the reaction temperature is 180-260 ℃, and the concentration of the NaOH solution is 65-80%; CN102534232A discloses that adding activated carbon into alkali solution with the concentration less than or equal to 75% to strengthen the extraction of chromium in vanadium slag, and the co-extraction of vanadium and chromium in vanadium slag can be realized at 200-225 ℃. CN105400967B discloses a method for co-extracting vanadium and chromium from vanadium slag, which further realizes the co-extraction of vanadium and chromium from vanadium slag by a micropore gas distribution device under the conditions of NaOH concentration of 40-70% and reaction temperature of 100-.

In summary, in the prior art, generally, the sodium removal treatment is performed on the vanadium extraction tailings separately in the later stage, and a post-treatment process needs to be added separately, so that a method capable of controlling the sodium content in the tailings from the source needs to be provided.

Disclosure of Invention

In order to solve the technical problems, the invention provides a method for cooperatively controlling the sodium content in tailings by extracting vanadium from vanadium slag, which can realize high-efficiency extraction of vanadium from vanadium slag and simultaneously can ensure that Na in tailings is extracted efficiently by strictly controlling the mass concentration of a sodium hydroxide solution and integrating other process conditions₂The content of O is controlled below 1 percent, and the tailings are easy to realize resource utilization.

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

in a first aspect, the invention provides a method for cooperatively controlling the sodium content in tailings by extracting vanadium from vanadium slag, which comprises the following steps:

(1) mixing vanadium slag, a calcium source and a NaOH solution with the mass concentration of 45-55 wt% to obtain mixed slurry;

(2) carrying out oxidation reaction on the mixed slurry obtained in the step (1) and oxidizing gas to obtain reacted slurry;

(3) and (3) carrying out solid-liquid separation on the slurry after the reaction in the step (2) to obtain tailings and vanadium-containing leaching liquid, and washing the tailings to obtain low-sodium tailings.

According to the invention, the concentration of the NaOH solution is strictly 45-55 wt%, so that the problem that sodium calcium silicate and sodium titanate which are generated and difficult to convert enter a slag phase and sodium is difficult to dissociate to cause overhigh sodium content in tailings can be effectively prevented, and the problem that the vanadium extraction rate is reduced due to overhigh system viscosity can be avoided; according to the method, 45-55% NaOH solution is used as a reaction medium, and a calcium source is used in combination, so that an aluminum-silicon-containing phase in the tailings can directly generate sodium-free calcium silicate and calcium aluminosilicate without influencing vanadium extraction efficiency, the sodium-containing phase in the tailings is prevented from being generated, and the low-sodium tailings are obtained by a one-step method.

Through the steps, the problem of efficient vanadium extraction in the vanadium slag vanadium extraction process and the control of the content of the sodium in the tailings are solved, and the obtained tailings can be recycled without secondary sodium removal treatment.

Preferably, the vanadium slag in step (1) is vanadium slag formed in the production processes of vanadium-containing pig iron (water) produced from vanadium titano-magnetite through a blast furnace or direct reduction process, and then vanadium extraction by using oxygen or air as an oxidation medium under high temperature conditions, such as ladle extraction, vanadium extraction by a top-blown converter or a top-bottom combined blown converter, and the like.

Preferably, the calcium source in step (1) comprises calcium oxide and/or calcium hydroxide.

When the mixture of calcium oxide and calcium hydroxide is used as the calcium source, the mixture of the calcium oxide and the calcium hydroxide in any proportion can be adopted.

Preferably, the mass concentration of the alkali in the NaOH solution is 48-52 wt%.

Preferably, the mass ratio of the vanadium slag to the calcium source in the step (1) is 10:1 to 10:3, for example, 10:1, 10:1.5, 10:2, 10:2.5 or 10:3, preferably 10:1.5 to 10: 2.5. And the specific values therebetween, are not exhaustive for the invention, but are limited to the space and for the sake of brevity.

Preferably, the liquid-solid ratio of the NaOH solution to the vanadium slag is 3:1 to 10:1, for example, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1 or 10:1, and preferably 5:1 to 7: 1. And the specific values therebetween, are not exhaustive for the invention, but are limited to the space and for the sake of brevity.

Preferably, the pressure of the oxidation reaction in the step (2) is less than or equal to 1 MPa.

The oxidation reaction in step (2) is carried out under normal pressure or low pressure, and when the reaction pressure is lower than 1MPa, for example, 0.1MPa, 0.2MPa, 0.3MPa, 0.4MPa, 0.5MPa, 0.6MPa, 0.7MPa, 0.8MPa, 0.9MPa or 1.0MPa, and the specific values between the above values are limited by space and simplicity, and the present invention is not exhaustive.

Preferably, the temperature of the oxidation reaction is 130 ℃ to 200 ℃, for example, 130 ℃, 140 ℃, 150 ℃, 160 ℃, 170 ℃, 180 ℃, 190 ℃ or 200 ℃, preferably 150 ℃ to 180 ℃. And the specific values therebetween, are not exhaustive for the invention, but are limited to the space and for the sake of brevity.

Preferably, the time of the oxidation reaction is more than or equal to 2 h.

The liquid phase oxidation reaction in the step (2) has a reaction time of more than 2h, preferably 2h to 6h, for example, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h, 5h, 5.5h or 6h, and the like, and the specific values between the above values are not exhaustive for the sake of brevity and simplicity.

Preferably, the oxidizing gas in step (2) comprises oxygen and/or air.

In the present invention, when a mixed gas of oxygen and air is used as the oxidizing gas, a mixed gas in which the oxygen and the air are mixed in an arbitrary ratio may be used.

Preferably, the slurry after the reaction in the step (3) is diluted and then subjected to solid-liquid separation.

Preferably, the diluent used for dilution comprises water and/or a vanadium slag vanadium extraction process circulating liquid.

Preferably, the mass concentration of NaOH in the diluted slurry in the step (3) is 18-45 wt%.

In the invention, the alkali concentration of the slurry after the liquid-phase oxidation reaction is higher, and the slurry can be directly subjected to liquid-solid separation, but the cost is higher; preferably, the reacted slurry is diluted by low-concentration liquid in a circulating process of a water and/or vanadium slag vanadium extraction process, and the concentration of NaOH in the diluted slurry is controlled to be 18-45 wt%, so that the liquid-solid separation of the reacted slurry is easier to operate.

Preferably, Na in the low-sodium tailings in the step (3)₂The content of O is less than or equal to 1wt percent.

As a preferred technical scheme of the invention, the method comprises the following steps:

(1) mixing vanadium slag, a calcium source and a NaOH solution with the mass concentration of 45-55 wt% to obtain mixed slurry; the mass ratio of the vanadium slag to the calcium source is 10: 1-10: 3, and the liquid-solid ratio of the NaOH solution to the vanadium slag is 3: 1-10: 1;

(2) carrying out oxidation reaction on the mixed slurry obtained in the step (1) and oxidizing gas for at least 2h under the conditions that the pressure is less than or equal to 1MPa and the temperature is 130-200 ℃ to obtain reacted slurry;

(3) carrying out solid-liquid separation on the slurry after the reaction in the step (2) to obtain tailings and vanadium-containing leaching solution, and washing the tailings to obtain Na₂Low-sodium tailings with the content of O less than or equal to 1 wt%.

According to the method, the process conditions such as the solution concentration, the addition amount, the calcium source addition amount, the reaction temperature and the like of the sodium hydroxide are comprehensively controlled, so that the phase structure of the tailings is adjusted, the sodium content in the tailings can be reduced while the vanadium extraction rate is high, the efficient extraction of vanadium in the vanadium slag and the source control of the sodium content in the tailings can be realized in one step, and the problems of long process and high cost in the existing process of carrying out independent sodium removal treatment on the tailings for resource utilization are solved.

The liquid-solid separation is not particularly limited in the present invention, and may be performed by any means in the art, such as any one or a combination of at least two of filtration, suction filtration, centrifugation, or sedimentation, but is not limited thereto, and the actual conditions should be combined in the production process for convenient operation.

The washing step is not particularly limited, and may be performed by any means conventional in the art, such as any one or a combination of at least two of the steps of washing, rinsing, and the like, but is not limited thereto, and the actual conditions should be combined in the production process to facilitate the operation.

In a second aspect, the invention provides a low-sodium tailings, which is prepared by the method for extracting vanadium from vanadium slag to cooperatively control the sodium content in the tailings.

Na in the low-sodium tailings provided by the invention₂The O content is within 1 wt%, and subsequent resource utilization can be realized without sodium removal treatment, so that the alkali load of the blast furnace lining is effectively reduced.

Compared with the prior art, the invention has at least the following beneficial effects:

(1) the method for cooperatively controlling the sodium content in the tailings by extracting vanadium from the vanadium slag does not generate dust and waste gas harmful to human and environment in the liquid-phase oxidation process, and is environment-friendly and safe;

(2) the method for cooperatively controlling the sodium content in the tailings by extracting vanadium from the vanadium slag synchronously realizes the control of the sodium content in the tailings in the vanadium extraction process, solves the problems of long process flow and high cost in the process of carrying out independent sodium removal treatment on the tailings after the tailings obtained by stacking and extracting vanadium in the traditional process are utilized as resources, and can obtain Na in one step when the vanadium extraction rate is more than or equal to 82 percent₂Vanadium extraction tailings with the O content of below 1 percent;

(3) the method for cooperatively controlling the sodium content in the tailings by extracting vanadium from the vanadium slag has the advantages of simple operation of the whole process, short flow and good economic benefit and application prospect.

Detailed Description

For the purpose of facilitating an understanding of the present invention, the present invention will now be described by way of examples. It should be understood by those skilled in the art that the examples are only for the understanding of the present invention and should not be construed as the specific limitations of the present invention.